Page MenuHome GnuPG
Files F25781864

dns.c
No OneTemporary
Actions

dns.c
View Options

This file is larger than 256 KB, so syntax highlighting was skipped.
/* ==========================================================================
* dns.c - Recursive, Reentrant DNS Resolver.
* --------------------------------------------------------------------------
* Copyright (c) 2008, 2009, 2010, 2012-2016 William Ahern
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to permit
* persons to whom the Software is furnished to do so, subject to the
* following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
* NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
* USE OR OTHER DEALINGS IN THE SOFTWARE.
* ==========================================================================
*/
#if HAVE_CONFIG_H
#include "config.h"
#elif !defined _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include <limits.h> /* INT_MAX */
#include <stdarg.h> /* va_list va_start va_end */
#include <stddef.h> /* offsetof() */
#ifdef _WIN32
/* JW: This breaks our mingw build: #define uint32_t unsigned int */
#else
#include <stdint.h> /* uint32_t */
#endif
#include <stdlib.h> /* malloc(3) realloc(3) free(3) rand(3) random(3) arc4random(3) */
#include <stdio.h> /* FILE fopen(3) fclose(3) getc(3) rewind(3) vsnprintf(3) */
#include <string.h> /* memcpy(3) strlen(3) memmove(3) memchr(3) memcmp(3) strchr(3) strsep(3) strcspn(3) */
#include <strings.h> /* strcasecmp(3) strncasecmp(3) */
#include <ctype.h> /* isspace(3) isdigit(3) */
#include <time.h> /* time_t time(2) difftime(3) */
#include <signal.h> /* SIGPIPE sigemptyset(3) sigaddset(3) sigpending(2) sigprocmask(2) pthread_sigmask(3) sigtimedwait(2) */
#include <errno.h> /* errno EINVAL ENOENT */
#undef NDEBUG
#include <assert.h> /* assert(3) */
#if _WIN32
#ifndef FD_SETSIZE
#define FD_SETSIZE 1024
#endif
#include <winsock2.h>
#include <ws2tcpip.h>
typedef SOCKET socket_fd_t;
#define STDCALL __stdcall
#ifdef TIME_WITH_SYS_TIME
#include <sys/time.h> /* gettimeofday(2) */
#endif
#else
typedef int socket_fd_t;
#define STDCALL
#include <sys/time.h> /* gettimeofday(2) */
#include <sys/types.h> /* FD_SETSIZE socklen_t */
#include <sys/select.h> /* FD_ZERO FD_SET fd_set select(2) */
#include <sys/socket.h> /* AF_INET AF_INET6 AF_UNIX struct sockaddr struct sockaddr_in struct sockaddr_in6 socket(2) */
#if defined(AF_UNIX)
#include <sys/un.h> /* struct sockaddr_un */
#endif
#include <fcntl.h> /* F_SETFD F_GETFL F_SETFL O_NONBLOCK fcntl(2) */
#include <unistd.h> /* _POSIX_THREADS gethostname(3) close(2) */
#include <poll.h> /* POLLIN POLLOUT */
#include <netinet/in.h> /* struct sockaddr_in struct sockaddr_in6 */
#include <arpa/inet.h> /* inet_pton(3) inet_ntop(3) htons(3) ntohs(3) */
#include <netdb.h> /* struct addrinfo */
#endif
#include "dns.h"
/*
* C O M P I L E R V E R S I O N & F E A T U R E D E T E C T I O N
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_GNUC_2VER(M, m, p) (((M) * 10000) + ((m) * 100) + (p))
#define DNS_GNUC_PREREQ(M, m, p) (__GNUC__ > 0 && DNS_GNUC_2VER(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__) >= DNS_GNUC_2VER((M), (m), (p)))
#define DNS_MSC_2VER(M, m, p) ((((M) + 6) * 10000000) + ((m) * 1000000) + (p))
#define DNS_MSC_PREREQ(M, m, p) (_MSC_VER_FULL > 0 && _MSC_VER_FULL >= DNS_MSC_2VER((M), (m), (p)))
#define DNS_SUNPRO_PREREQ(M, m, p) (__SUNPRO_C > 0 && __SUNPRO_C >= 0x ## M ## m ## p)
#if defined __has_builtin
#define dns_has_builtin(x) __has_builtin(x)
#else
#define dns_has_builtin(x) 0
#endif
#if defined __has_extension
#define dns_has_extension(x) __has_extension(x)
#else
#define dns_has_extension(x) 0
#endif
#ifndef HAVE___ASSUME
#define HAVE___ASSUME DNS_MSC_PREREQ(8,0,0)
#endif
#ifndef HAVE___BUILTIN_TYPES_COMPATIBLE_P
#define HAVE___BUILTIN_TYPES_COMPATIBLE_P (DNS_GNUC_PREREQ(3,1,1) || __clang__)
#endif
#ifndef HAVE___BUILTIN_UNREACHABLE
#define HAVE___BUILTIN_UNREACHABLE (DNS_GNUC_PREREQ(4,5,0) || dns_has_builtin(__builtin_unreachable))
#endif
#ifndef HAVE_PRAGMA_MESSAGE
#define HAVE_PRAGMA_MESSAGE (DNS_GNUC_PREREQ(4,4,0) || __clang__ || _MSC_VER)
#endif
/*
* C O M P I L E R A N N O T A T I O N S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if __GNUC__
#define DNS_NOTUSED __attribute__((unused))
#define DNS_NORETURN __attribute__((noreturn))
#else
#define DNS_NOTUSED
#define DNS_NORETURN
#endif
#if __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-parameter"
#pragma clang diagnostic ignored "-Wmissing-field-initializers"
#elif DNS_GNUC_PREREQ(4,6,0)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#endif
/*
* S T A N D A R D M A C R O S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if HAVE___BUILTIN_TYPES_COMPATIBLE_P
#define dns_same_type(a, b, def) __builtin_types_compatible_p(__typeof__ (a), __typeof__ (b))
#else
#define dns_same_type(a, b, def) (def)
#endif
#define dns_isarray(a) (!dns_same_type((a), (&(a)[0]), 0))
/* NB: "_" field silences Sun Studio "zero-sized struct/union" error diagnostic */
#define dns_inline_assert(cond) ((void)(sizeof (struct { int:-!(cond); int _; })))
#if HAVE___ASSUME
#define dns_assume(cond) __assume(cond)
#elif HAVE___BUILTIN_UNREACHABLE
#define dns_assume(cond) do { if (!(cond)) __builtin_unreachable(); } while (0)
#else
#define dns_assume(cond) do { (void)(cond); } while (0)
#endif
#ifndef lengthof
#define lengthof(a) (dns_inline_assert(dns_isarray(a)), (sizeof (a) / sizeof (a)[0]))
#endif
#ifndef endof
#define endof(a) (dns_inline_assert(dns_isarray(a)), &(a)[lengthof((a))])
#endif
/*
* M I S C E L L A N E O U S C O M P A T
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if _WIN32 || _WIN64
#define PRIuZ "Iu"
#else
#define PRIuZ "zu"
#endif
#ifndef DNS_THREAD_SAFE
#if (defined _REENTRANT || defined _THREAD_SAFE) && _POSIX_THREADS > 0
#define DNS_THREAD_SAFE 1
#else
#define DNS_THREAD_SAFE 0
#endif
#endif
#ifndef HAVE__STATIC_ASSERT
#define HAVE__STATIC_ASSERT \
(dns_has_extension(c_static_assert) || DNS_GNUC_PREREQ(4,6,0) || \
__C11FEATURES__ || __STDC_VERSION__ >= 201112L)
#endif
#ifndef HAVE_STATIC_ASSERT
#if DNS_GNUC_PREREQ(0,0,0) && !DNS_GNUC_PREREQ(4,6,0)
#define HAVE_STATIC_ASSERT 0 /* glibc doesn't check GCC version */
#elif defined(static_assert)
#define HAVE_STATIC_ASSERT 1
#else
#define HAVE_STATIC_ASSERT 0
#endif
#endif
#if HAVE_STATIC_ASSERT
#define dns_static_assert(cond, msg) static_assert(cond, msg)
#elif HAVE__STATIC_ASSERT
#define dns_static_assert(cond, msg) _Static_assert(cond, msg)
#else
#define dns_static_assert(cond, msg) extern char DNS_PP_XPASTE(dns_assert_, __LINE__)[sizeof (int[1 - 2*!(cond)])]
#endif
/*
* D E B U G M A C R O S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
int *dns_debug_p(void) {
static int debug;
return &debug;
} /* dns_debug_p() */
#if DNS_DEBUG
#undef DNS_DEBUG
#define DNS_DEBUG dns_debug
#define DNS_SAY_(fmt, ...) \
do { if (DNS_DEBUG > 0) fprintf(stderr, fmt "%.1s", __func__, __LINE__, __VA_ARGS__); } while (0)
#define DNS_SAY(...) DNS_SAY_("@@ (%s:%d) " __VA_ARGS__, "\n")
#define DNS_HAI DNS_SAY("HAI")
#define DNS_SHOW_(P, fmt, ...) do { \
if (DNS_DEBUG > 1) { \
fprintf(stderr, "@@ BEGIN * * * * * * * * * * * *\n"); \
fprintf(stderr, "@@ " fmt "%.0s\n", __VA_ARGS__); \
dns_p_dump((P), stderr); \
fprintf(stderr, "@@ END * * * * * * * * * * * * *\n\n"); \
} \
} while (0)
#define DNS_SHOW(...) DNS_SHOW_(__VA_ARGS__, "")
#else /* !DNS_DEBUG */
#undef DNS_DEBUG
#define DNS_DEBUG 0
#define DNS_SAY(...)
#define DNS_HAI
#define DNS_SHOW(...)
#endif /* DNS_DEBUG */
#define DNS_CARP(...) DNS_SAY(__VA_ARGS__)
/*
* V E R S I O N R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
const char *dns_vendor(void) {
return DNS_VENDOR;
} /* dns_vendor() */
int dns_v_rel(void) {
return DNS_V_REL;
} /* dns_v_rel() */
int dns_v_abi(void) {
return DNS_V_ABI;
} /* dns_v_abi() */
int dns_v_api(void) {
return DNS_V_API;
} /* dns_v_api() */
/*
* E R R O R R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#ifndef EPROTO
# define EPROTO EPROTONOSUPPORT
#endif
#if _WIN32
#define DNS_EINTR WSAEINTR
#define DNS_EINPROGRESS WSAEINPROGRESS
#define DNS_EISCONN WSAEISCONN
#define DNS_EWOULDBLOCK WSAEWOULDBLOCK
#define DNS_EALREADY WSAEALREADY
#define DNS_EAGAIN EAGAIN
#define DNS_ETIMEDOUT WSAETIMEDOUT
#define dns_syerr() ((int)GetLastError())
#define dns_soerr() ((int)WSAGetLastError())
#else
#define DNS_EINTR EINTR
#define DNS_EINPROGRESS EINPROGRESS
#define DNS_EISCONN EISCONN
#define DNS_EWOULDBLOCK EWOULDBLOCK
#define DNS_EALREADY EALREADY
#define DNS_EAGAIN EAGAIN
#define DNS_ETIMEDOUT ETIMEDOUT
#define dns_syerr() errno
#define dns_soerr() errno
#endif
const char *dns_strerror(int error) {
switch (error) {
case DNS_ENOBUFS:
return "DNS packet buffer too small";
case DNS_EILLEGAL:
return "Illegal DNS RR name or data";
case DNS_EORDER:
return "Attempt to push RR out of section order";
case DNS_ESECTION:
return "Invalid section specified";
case DNS_EUNKNOWN:
return "Unknown DNS error";
case DNS_EADDRESS:
return "Invalid textual address form";
case DNS_ENOQUERY:
return "Bad execution state (missing query packet)";
case DNS_ENOANSWER:
return "Bad execution state (missing answer packet)";
case DNS_EFETCHED:
return "Answer already fetched";
case DNS_ESERVICE:
return "The service passed was not recognized for the specified socket type";
case DNS_ENONAME:
return "The name does not resolve for the supplied parameters";
case DNS_EFAIL:
return "A non-recoverable error occurred when attempting to resolve the name";
case DNS_ECONNFIN:
return "Connection closed";
case DNS_EVERIFY:
return "Reply failed verification";
default:
return strerror(error);
} /* switch() */
} /* dns_strerror() */
/*
* A T O M I C R O U T I N E S
*
* Use GCC's __atomic built-ins if possible. Unlike the __sync built-ins, we
* can use the preprocessor to detect API and, more importantly, ISA
* support. We want to avoid linking headaches where the API depends on an
* external library if the ISA (e.g. i386) doesn't support lockless
* operation.
*
* TODO: Support C11's atomic API. Although that may require some finesse
* with how we define some public types, such as dns_atomic_t and struct
* dns_resolv_conf.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#ifndef HAVE___ATOMIC_FETCH_ADD
#ifdef __ATOMIC_RELAXED
#define HAVE___ATOMIC_FETCH_ADD 1
#else
#define HAVE___ATOMIC_FETCH_ADD 0
#endif
#endif
#ifndef HAVE___ATOMIC_FETCH_SUB
#define HAVE___ATOMIC_FETCH_SUB HAVE___ATOMIC_FETCH_ADD
#endif
#ifndef DNS_ATOMIC_FETCH_ADD
#if HAVE___ATOMIC_FETCH_ADD && __GCC_ATOMIC_LONG_LOCK_FREE == 2
#define DNS_ATOMIC_FETCH_ADD(i) __atomic_fetch_add((i), 1, __ATOMIC_RELAXED)
#else
#pragma message("no atomic_fetch_add available")
#define DNS_ATOMIC_FETCH_ADD(i) ((*(i))++)
#endif
#endif
#ifndef DNS_ATOMIC_FETCH_SUB
#if HAVE___ATOMIC_FETCH_SUB && __GCC_ATOMIC_LONG_LOCK_FREE == 2
#define DNS_ATOMIC_FETCH_SUB(i) __atomic_fetch_sub((i), 1, __ATOMIC_RELAXED)
#else
#pragma message("no atomic_fetch_sub available")
#define DNS_ATOMIC_FETCH_SUB(i) ((*(i))--)
#endif
#endif
static inline unsigned dns_atomic_fetch_add(dns_atomic_t *i) {
return DNS_ATOMIC_FETCH_ADD(i);
} /* dns_atomic_fetch_add() */
static inline unsigned dns_atomic_fetch_sub(dns_atomic_t *i) {
return DNS_ATOMIC_FETCH_SUB(i);
} /* dns_atomic_fetch_sub() */
/*
* C R Y P T O R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* P R N G
*/
#ifndef DNS_RANDOM
#if defined(HAVE_ARC4RANDOM) \
|| defined(__OpenBSD__) \
|| defined(__FreeBSD__) \
|| defined(__NetBSD__) \
|| defined(__APPLE__)
#define DNS_RANDOM arc4random
#elif __linux
#define DNS_RANDOM random
#else
#define DNS_RANDOM rand
#endif
#endif
#define DNS_RANDOM_arc4random 1
#define DNS_RANDOM_random 2
#define DNS_RANDOM_rand 3
#define DNS_RANDOM_RAND_bytes 4
#define DNS_RANDOM_OPENSSL (DNS_RANDOM_RAND_bytes == DNS_PP_XPASTE(DNS_RANDOM_, DNS_RANDOM))
#if DNS_RANDOM_OPENSSL
#include <openssl/rand.h>
#endif
static unsigned dns_random_(void) {
#if DNS_RANDOM_OPENSSL
unsigned r;
_Bool ok;
ok = (1 == RAND_bytes((unsigned char *)&r, sizeof r));
assert(ok && "1 == RAND_bytes()");
return r;
#else
return DNS_RANDOM();
#endif
} /* dns_random_() */
dns_random_f **dns_random_p(void) {
static dns_random_f *random_f = &dns_random_;
return &random_f;
} /* dns_random_p() */
/*
* P E R M U T A T I O N G E N E R A T O R
*/
#define DNS_K_TEA_KEY_SIZE 16
#define DNS_K_TEA_BLOCK_SIZE 8
#define DNS_K_TEA_CYCLES 32
#define DNS_K_TEA_MAGIC 0x9E3779B9U
struct dns_k_tea {
uint32_t key[DNS_K_TEA_KEY_SIZE / sizeof (uint32_t)];
unsigned cycles;
}; /* struct dns_k_tea */
static void dns_k_tea_init(struct dns_k_tea *tea, uint32_t key[], unsigned cycles) {
memcpy(tea->key, key, sizeof tea->key);
tea->cycles = (cycles)? cycles : DNS_K_TEA_CYCLES;
} /* dns_k_tea_init() */
static void dns_k_tea_encrypt(struct dns_k_tea *tea, uint32_t v[], uint32_t *w) {
uint32_t y, z, sum, n;
y = v[0];
z = v[1];
sum = 0;
for (n = 0; n < tea->cycles; n++) {
sum += DNS_K_TEA_MAGIC;
y += ((z << 4) + tea->key[0]) ^ (z + sum) ^ ((z >> 5) + tea->key[1]);
z += ((y << 4) + tea->key[2]) ^ (y + sum) ^ ((y >> 5) + tea->key[3]);
}
w[0] = y;
w[1] = z;
return /* void */;
} /* dns_k_tea_encrypt() */
/*
* Permutation generator, based on a Luby-Rackoff Feistel construction.
*
* Specifically, this is a generic balanced Feistel block cipher using TEA
* (another block cipher) as the pseudo-random function, F. At best it's as
* strong as F (TEA), notwithstanding the seeding. F could be AES, SHA-1, or
* perhaps Bernstein's Salsa20 core; I am naively trying to keep things
* simple.
*
* The generator can create a permutation of any set of numbers, as long as
* the size of the set is an even power of 2. This limitation arises either
* out of an inherent property of balanced Feistel constructions, or by my
* own ignorance. I'll tackle an unbalanced construction after I wrap my
* head around Schneier and Kelsey's paper.
*
* CAVEAT EMPTOR. IANAC.
*/
#define DNS_K_PERMUTOR_ROUNDS 8
struct dns_k_permutor {
unsigned stepi, length, limit;
unsigned shift, mask, rounds;
struct dns_k_tea tea;
}; /* struct dns_k_permutor */
static inline unsigned dns_k_permutor_powof(unsigned n) {
unsigned m, i = 0;
for (m = 1; m < n; m <<= 1, i++)
;;
return i;
} /* dns_k_permutor_powof() */
static void dns_k_permutor_init(struct dns_k_permutor *p, unsigned low, unsigned high) {
uint32_t key[DNS_K_TEA_KEY_SIZE / sizeof (uint32_t)];
unsigned width, i;
p->stepi = 0;
p->length = (high - low) + 1;
p->limit = high;
width = dns_k_permutor_powof(p->length);
width += width % 2;
p->shift = width / 2;
p->mask = (1U << p->shift) - 1;
p->rounds = DNS_K_PERMUTOR_ROUNDS;
for (i = 0; i < lengthof(key); i++)
key[i] = dns_random();
dns_k_tea_init(&p->tea, key, 0);
return /* void */;
} /* dns_k_permutor_init() */
static unsigned dns_k_permutor_F(struct dns_k_permutor *p, unsigned k, unsigned x) {
uint32_t in[DNS_K_TEA_BLOCK_SIZE / sizeof (uint32_t)], out[DNS_K_TEA_BLOCK_SIZE / sizeof (uint32_t)];
memset(in, '\0', sizeof in);
in[0] = k;
in[1] = x;
dns_k_tea_encrypt(&p->tea, in, out);
return p->mask & out[0];
} /* dns_k_permutor_F() */
static unsigned dns_k_permutor_E(struct dns_k_permutor *p, unsigned n) {
unsigned l[2], r[2];
unsigned i;
i = 0;
l[i] = p->mask & (n >> p->shift);
r[i] = p->mask & (n >> 0);
do {
l[(i + 1) % 2] = r[i % 2];
r[(i + 1) % 2] = l[i % 2] ^ dns_k_permutor_F(p, i, r[i % 2]);
i++;
} while (i < p->rounds - 1);
return ((l[i % 2] & p->mask) << p->shift) | ((r[i % 2] & p->mask) << 0);
} /* dns_k_permutor_E() */
DNS_NOTUSED static unsigned dns_k_permutor_D(struct dns_k_permutor *p, unsigned n) {
unsigned l[2], r[2];
unsigned i;
i = p->rounds - 1;
l[i % 2] = p->mask & (n >> p->shift);
r[i % 2] = p->mask & (n >> 0);
do {
i--;
r[i % 2] = l[(i + 1) % 2];
l[i % 2] = r[(i + 1) % 2] ^ dns_k_permutor_F(p, i, l[(i + 1) % 2]);
} while (i > 0);
return ((l[i % 2] & p->mask) << p->shift) | ((r[i % 2] & p->mask) << 0);
} /* dns_k_permutor_D() */
static unsigned dns_k_permutor_step(struct dns_k_permutor *p) {
unsigned n;
do {
n = dns_k_permutor_E(p, p->stepi++);
} while (n >= p->length);
return n + (p->limit + 1 - p->length);
} /* dns_k_permutor_step() */
/*
* Simple permutation box. Useful for shuffling rrsets from an iterator.
* Uses AES s-box to provide good diffusion.
*
* Seems to pass muster under runs test.
*
* $ for i in 0 1 2 3 4 5 6 7 8 9; do ./dns shuffle-16 > /tmp/out; done
* $ R -q -f /dev/stdin 2>/dev/null <<-EOF | awk '/p-value/{ print $8 }'
* library(lawstat)
* runs.test(scan(file="/tmp/out"))
* EOF
*/
static unsigned short dns_k_shuffle16(unsigned short n, unsigned s) {
static const unsigned char sbox[256] =
{ 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
unsigned char a, b;
unsigned i;
a = 0xff & (n >> 0);
b = 0xff & (n >> 8);
for (i = 0; i < 4; i++) {
a ^= 0xff & s;
a = sbox[a] ^ b;
b = sbox[b] ^ a;
s >>= 8;
}
return ((0xff00 & (a << 8)) | (0x00ff & (b << 0)));
} /* dns_k_shuffle16() */
/*
* S T A T E M A C H I N E R O U T I N E S
*
* Application code should define DNS_SM_RESTORE and DNS_SM_SAVE, and the
* local variable pc.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_SM_ENTER \
do { \
static const int pc0 = __LINE__; \
DNS_SM_RESTORE; \
switch (pc0 + pc) { \
case __LINE__: (void)0
#define DNS_SM_SAVE_AND_DO(do_statement) \
do { \
pc = __LINE__ - pc0; \
DNS_SM_SAVE; \
do_statement; \
case __LINE__: (void)0; \
} while (0)
#define DNS_SM_YIELD(rv) \
DNS_SM_SAVE_AND_DO(return (rv))
#define DNS_SM_EXIT \
do { goto leave; } while (0)
#define DNS_SM_LEAVE \
leave: (void)0; \
DNS_SM_SAVE_AND_DO(break); \
} \
} while (0)
/*
* U T I L I T Y R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_MAXINTERVAL 300
struct dns_clock {
time_t sample, elapsed;
}; /* struct dns_clock */
static void dns_begin(struct dns_clock *clk) {
clk->sample = time(0);
clk->elapsed = 0;
} /* dns_begin() */
static time_t dns_elapsed(struct dns_clock *clk) {
time_t curtime;
if ((time_t)-1 == time(&curtime))
return clk->elapsed;
if (curtime > clk->sample)
clk->elapsed += (time_t)DNS_PP_MIN(difftime(curtime, clk->sample), DNS_MAXINTERVAL);
clk->sample = curtime;
return clk->elapsed;
} /* dns_elapsed() */
DNS_NOTUSED static size_t dns_strnlen(const char *src, size_t m) {
size_t n = 0;
while (*src++ && n < m)
++n;
return n;
} /* dns_strnlen() */
DNS_NOTUSED static size_t dns_strnlcpy(char *dst, size_t lim, const char *src, size_t max) {
size_t len = dns_strnlen(src, max), n;
if (lim > 0) {
n = DNS_PP_MIN(lim - 1, len);
memcpy(dst, src, n);
dst[n] = '\0';
}
return len;
} /* dns_strnlcpy() */
#if (defined AF_UNIX && !defined _WIN32)
#define DNS_HAVE_SOCKADDR_UN 1
#else
#define DNS_HAVE_SOCKADDR_UN 0
#endif
static size_t dns_af_len(int af) {
static const size_t table[AF_MAX] = {
[AF_INET6] = sizeof (struct sockaddr_in6),
[AF_INET] = sizeof (struct sockaddr_in),
#if DNS_HAVE_SOCKADDR_UN
[AF_UNIX] = sizeof (struct sockaddr_un),
#endif
};
return table[af];
} /* dns_af_len() */
#define dns_sa_family(sa) (((struct sockaddr *)(sa))->sa_family)
#define dns_sa_len(sa) dns_af_len(dns_sa_family(sa))
#define DNS_SA_NOPORT &dns_sa_noport
static unsigned short dns_sa_noport;
static unsigned short *dns_sa_port(int af, void *sa) {
switch (af) {
case AF_INET6:
return &((struct sockaddr_in6 *)sa)->sin6_port;
case AF_INET:
return &((struct sockaddr_in *)sa)->sin_port;
default:
return DNS_SA_NOPORT;
}
} /* dns_sa_port() */
static void *dns_sa_addr(int af, const void *sa, socklen_t *size) {
switch (af) {
case AF_INET6: {
struct in6_addr *in6 = &((struct sockaddr_in6 *)sa)->sin6_addr;
if (size)
*size = sizeof *in6;
return in6;
}
case AF_INET: {
struct in_addr *in = &((struct sockaddr_in *)sa)->sin_addr;
if (size)
*size = sizeof *in;
return in;
}
default:
if (size)
*size = 0;
return 0;
}
} /* dns_sa_addr() */
#if DNS_HAVE_SOCKADDR_UN
#define DNS_SUNPATHMAX (sizeof ((struct sockaddr_un *)0)->sun_path)
#endif
DNS_NOTUSED static void *dns_sa_path(void *sa, socklen_t *size) {
switch (dns_sa_family(sa)) {
#if DNS_HAVE_SOCKADDR_UN
case AF_UNIX: {
char *path = ((struct sockaddr_un *)sa)->sun_path;
if (size)
*size = dns_strnlen(path, DNS_SUNPATHMAX);
return path;
}
#endif
default:
if (size)
*size = 0;
return NULL;
}
} /* dns_sa_path() */
static int dns_sa_cmp(void *a, void *b) {
int cmp, af;
if ((cmp = dns_sa_family(a) - dns_sa_family(b)))
return cmp;
switch ((af = dns_sa_family(a))) {
case AF_INET: {
struct in_addr *a4, *b4;
if ((cmp = htons(*dns_sa_port(af, a)) - htons(*dns_sa_port(af, b))))
return cmp;
a4 = dns_sa_addr(af, a, NULL);
b4 = dns_sa_addr(af, b, NULL);
if (ntohl(a4->s_addr) < ntohl(b4->s_addr))
return -1;
if (ntohl(a4->s_addr) > ntohl(b4->s_addr))
return 1;
return 0;
}
case AF_INET6: {
struct in6_addr *a6, *b6;
size_t i;
if ((cmp = htons(*dns_sa_port(af, a)) - htons(*dns_sa_port(af, b))))
return cmp;
a6 = dns_sa_addr(af, a, NULL);
b6 = dns_sa_addr(af, b, NULL);
/* XXX: do we need to use in6_clearscope()? */
for (i = 0; i < sizeof a6->s6_addr; i++) {
if ((cmp = a6->s6_addr[i] - b6->s6_addr[i]))
return cmp;
}
return 0;
}
#if DNS_HAVE_SOCKADDR_UN
case AF_UNIX: {
char a_path[DNS_SUNPATHMAX + 1], b_path[sizeof a_path];
dns_strnlcpy(a_path, sizeof a_path, dns_sa_path(a, NULL), DNS_SUNPATHMAX);
dns_strnlcpy(b_path, sizeof b_path, dns_sa_path(b, NULL), DNS_SUNPATHMAX);
return strcmp(a_path, b_path);
}
#endif
default:
return -1;
}
} /* dns_sa_cmp() */
#if _WIN32
static int dns_inet_pton(int af, const void *src, void *dst) {
union { struct sockaddr_in sin; struct sockaddr_in6 sin6; } u;
u.sin.sin_family = af;
if (0 != WSAStringToAddressA((void *)src, af, (void *)0, (struct sockaddr *)&u, &(int){ sizeof u }))
return -1;
switch (af) {
case AF_INET6:
*(struct in6_addr *)dst = u.sin6.sin6_addr;
return 1;
case AF_INET:
*(struct in_addr *)dst = u.sin.sin_addr;
return 1;
default:
return 0;
}
} /* dns_inet_pton() */
static const char *dns_inet_ntop(int af, const void *src, void *dst, unsigned long lim) {
union { struct sockaddr_in sin; struct sockaddr_in6 sin6; } u;
/* NOTE: WSAAddressToString will print .sin_port unless zeroed. */
memset(&u, 0, sizeof u);
u.sin.sin_family = af;
switch (af) {
case AF_INET6:
u.sin6.sin6_addr = *(struct in6_addr *)src;
break;
case AF_INET:
u.sin.sin_addr = *(struct in_addr *)src;
break;
default:
return 0;
}
if (0 != WSAAddressToStringA((struct sockaddr *)&u, dns_sa_len(&u), (void *)0, dst, &lim))
return 0;
return dst;
} /* dns_inet_ntop() */
#else
#define dns_inet_pton(...) inet_pton(__VA_ARGS__)
#define dns_inet_ntop(...) inet_ntop(__VA_ARGS__)
#endif
static dns_error_t dns_pton(int af, const void *src, void *dst) {
switch (dns_inet_pton(af, src, dst)) {
case 1:
return 0;
case -1:
return dns_soerr();
default:
return DNS_EADDRESS;
}
} /* dns_pton() */
static dns_error_t dns_ntop(int af, const void *src, void *dst, unsigned long lim) {
return (dns_inet_ntop(af, src, dst, lim))? 0 : dns_soerr();
} /* dns_ntop() */
size_t dns_strlcpy(char *dst, const char *src, size_t lim) {
char *d = dst;
char *e = &dst[lim];
const char *s = src;
if (d < e) {
do {
if ('\0' == (*d++ = *s++))
return s - src - 1;
} while (d < e);
d[-1] = '\0';
}
while (*s++ != '\0')
;;
return s - src - 1;
} /* dns_strlcpy() */
size_t dns_strlcat(char *dst, const char *src, size_t lim) {
char *d = memchr(dst, '\0', lim);
char *e = &dst[lim];
const char *s = src;
const char *p;
if (d && d < e) {
do {
if ('\0' == (*d++ = *s++))
return d - dst - 1;
} while (d < e);
d[-1] = '\0';
}
p = s;
while (*s++ != '\0')
;;
return lim + (s - p - 1);
} /* dns_strlcat() */
static void *dns_reallocarray(void *p, size_t nmemb, size_t size, dns_error_t *error) {
void *rp;
if (nmemb > 0 && SIZE_MAX / nmemb < size) {
*error = EOVERFLOW;
return NULL;
}
if (!(rp = realloc(p, nmemb * size)))
*error = (errno)? errno : EINVAL;
return rp;
} /* dns_reallocarray() */
#if _WIN32
static char *dns_strsep(char **sp, const char *delim) {
char *p;
if (!(p = *sp))
return 0;
*sp += strcspn(p, delim);
if (**sp != '\0') {
**sp = '\0';
++*sp;
} else
*sp = NULL;
return p;
} /* dns_strsep() */
#else
#define dns_strsep(...) strsep(__VA_ARGS__)
#endif
#if _WIN32
#define strcasecmp(...) _stricmp(__VA_ARGS__)
#define strncasecmp(...) _strnicmp(__VA_ARGS__)
#endif
static inline _Bool dns_isalpha(unsigned char c) {
return isalpha(c);
} /* dns_isalpha() */
static inline _Bool dns_isdigit(unsigned char c) {
return isdigit(c);
} /* dns_isdigit() */
static inline _Bool dns_isalnum(unsigned char c) {
return isalnum(c);
} /* dns_isalnum() */
static inline _Bool dns_isspace(unsigned char c) {
return isspace(c);
} /* dns_isspace() */
static inline _Bool dns_isgraph(unsigned char c) {
return isgraph(c);
} /* dns_isgraph() */
static int dns_poll(int fd, short events, int timeout) {
fd_set rset, wset;
if (!events)
return 0;
if (fd < 0 || (unsigned)fd >= FD_SETSIZE)
return EINVAL;
FD_ZERO(&rset);
FD_ZERO(&wset);
if (events & DNS_POLLIN)
FD_SET(fd, &rset);
if (events & DNS_POLLOUT)
FD_SET(fd, &wset);
select(fd + 1, &rset, &wset, 0, (timeout >= 0)? &(struct timeval){ timeout, 0 } : NULL);
return 0;
} /* dns_poll() */
#if !_WIN32
DNS_NOTUSED static int dns_sigmask(int how, const sigset_t *set, sigset_t *oset) {
#if DNS_THREAD_SAFE
return pthread_sigmask(how, set, oset);
#else
return (0 == sigprocmask(how, set, oset))? 0 : errno;
#endif
} /* dns_sigmask() */
#endif
static size_t dns_send(int fd, const void *src, size_t len, int flags, dns_error_t *error) {
long n = send(fd, src, len, flags);
if (n < 0) {
*error = dns_soerr();
return 0;
} else {
*error = 0;
return n;
}
} /* dns_send() */
static size_t dns_recv(int fd, void *dst, size_t lim, int flags, dns_error_t *error) {
long n = recv(fd, dst, lim, flags);
if (n < 0) {
*error = dns_soerr();
return 0;
} else if (n == 0) {
*error = (lim > 0)? DNS_ECONNFIN : EINVAL;
return 0;
} else {
*error = 0;
return n;
}
} /* dns_recv() */
static size_t dns_send_nopipe(int fd, const void *src, size_t len, int flags, dns_error_t *_error) {
#if _WIN32 || !defined SIGPIPE || defined SO_NOSIGPIPE
return dns_send(fd, src, len, flags, _error);
#elif defined MSG_NOSIGNAL
return dns_send(fd, src, len, (flags|MSG_NOSIGNAL), _error);
#elif _POSIX_REALTIME_SIGNALS > 0 /* require sigtimedwait */
/*
* SIGPIPE handling similar to the approach described in
* http://krokisplace.blogspot.com/2010/02/suppressing-sigpipe-in-library.html
*/
sigset_t pending, blocked, piped;
size_t count;
int error;
sigemptyset(&pending);
sigpending(&pending);
if (!sigismember(&pending, SIGPIPE)) {
sigemptyset(&piped);
sigaddset(&piped, SIGPIPE);
sigemptyset(&blocked);
if ((error = dns_sigmask(SIG_BLOCK, &piped, &blocked)))
goto error;
}
count = dns_send(fd, src, len, flags, &error);
if (!sigismember(&pending, SIGPIPE)) {
int saved = error;
if (!count && error == EPIPE) {
while (-1 == sigtimedwait(&piped, NULL, &(struct timespec){ 0, 0 }) && errno == EINTR)
;;
}
if ((error = dns_sigmask(SIG_SETMASK, &blocked, NULL)))
goto error;
error = saved;
}
*_error = error;
return count;
error:
*_error = error;
return 0;
#else
#error "unable to suppress SIGPIPE"
return dns_send(fd, src, len, flags, _error);
#endif
} /* dns_send_nopipe() */
static dns_error_t dns_connect(int fd, const struct sockaddr *addr, socklen_t addrlen) {
if (0 != connect(fd, addr, addrlen))
return dns_soerr();
return 0;
} /* dns_connect() */
#define DNS_FOPEN_STDFLAGS "rwabt+"
static dns_error_t dns_fopen_addflag(char *dst, const char *src, size_t lim, int fc) {
char *p = dst, *pe = dst + lim;
/* copy standard flags */
while (*src && strchr(DNS_FOPEN_STDFLAGS, *src)) {
if (!(p < pe))
return ENOMEM;
*p++ = *src++;
}
/* append flag to standard flags */
if (!(p < pe))
return ENOMEM;
*p++ = fc;
/* copy remaining mode string, including '\0' */
do {
if (!(p < pe))
return ENOMEM;
} while ((*p++ = *src++));
return 0;
} /* dns_fopen_addflag() */
static FILE *dns_fopen(const char *path, const char *mode, dns_error_t *_error) {
FILE *fp;
char mode_cloexec[32];
int error;
assert(path && mode && *mode);
if (!*path) {
error = EINVAL;
goto error;
}
#if _WIN32 || _WIN64
if ((error = dns_fopen_addflag(mode_cloexec, mode, sizeof mode_cloexec, 'N')))
goto error;
if (!(fp = fopen(path, mode_cloexec)))
goto syerr;
#else
if ((error = dns_fopen_addflag(mode_cloexec, mode, sizeof mode_cloexec, 'e')))
goto error;
if (!(fp = fopen(path, mode_cloexec))) {
if (errno != EINVAL)
goto syerr;
if (!(fp = fopen(path, mode)))
goto syerr;
}
#endif
return fp;
syerr:
error = dns_syerr();
error:
*_error = error;
return NULL;
} /* dns_fopen() */
struct dns_hxd_lines_i {
int pc;
size_t p;
};
#define DNS_SM_RESTORE \
do { \
pc = state->pc; \
sp = src + state->p; \
se = src + len; \
} while (0)
#define DNS_SM_SAVE \
do { \
state->p = sp - src; \
state->pc = pc; \
} while (0)
static size_t dns_hxd_lines(void *dst, size_t lim, const unsigned char *src, size_t len, struct dns_hxd_lines_i *state) {
static const unsigned char hex[] = "0123456789abcdef";
static const unsigned char tmpl[] = " | |\n";
unsigned char ln[sizeof tmpl];
const unsigned char *sp, *se;
unsigned char *h, *g;
unsigned i, n;
int pc;
DNS_SM_ENTER;
while (sp < se) {
memcpy(ln, tmpl, sizeof ln);
h = &ln[2];
g = &ln[53];
for (n = 0; n < 2; n++) {
for (i = 0; i < 8 && se - sp > 0; i++, sp++) {
h[0] = hex[0x0f & (*sp >> 4)];
h[1] = hex[0x0f & (*sp >> 0)];
h += 3;
*g++ = (dns_isgraph(*sp))? *sp : '.';
}
h++;
}
n = dns_strlcpy(dst, (char *)ln, lim);
DNS_SM_YIELD(n);
}
DNS_SM_EXIT;
DNS_SM_LEAVE;
return 0;
}
#undef DNS_SM_SAVE
#undef DNS_SM_RESTORE
/*
* A R I T H M E T I C R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_CHECK_OVERFLOW(error, r, f, ...) \
do { \
uintmax_t _r; \
*(error) = f(&_r, __VA_ARGS__); \
*(r) = _r; \
} while (0)
static dns_error_t dns_clamp_overflow(uintmax_t *r, uintmax_t n, uintmax_t clamp) {
if (n > clamp) {
*r = clamp;
return ERANGE;
} else {
*r = n;
return 0;
}
} /* dns_clamp_overflow() */
static dns_error_t dns_add_overflow(uintmax_t *r, uintmax_t a, uintmax_t b, uintmax_t clamp) {
if (~a < b) {
*r = DNS_PP_MIN(clamp, ~UINTMAX_C(0));
return ERANGE;
} else {
return dns_clamp_overflow(r, a + b, clamp);
}
} /* dns_add_overflow() */
static dns_error_t dns_mul_overflow(uintmax_t *r, uintmax_t a, uintmax_t b, uintmax_t clamp) {
if (a > 0 && UINTMAX_MAX / a < b) {
*r = DNS_PP_MIN(clamp, ~UINTMAX_C(0));
return ERANGE;
} else {
return dns_clamp_overflow(r, a * b, clamp);
}
} /* dns_mul_overflow() */
/*
* F I X E D - S I Z E D B U F F E R R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_B_INIT(src, n) { \
(unsigned char *)(src), \
(unsigned char *)(src), \
(unsigned char *)(src) + (n), \
}
#define DNS_B_FROM(src, n) DNS_B_INIT((src), (n))
#define DNS_B_INTO(src, n) DNS_B_INIT((src), (n))
struct dns_buf {
const unsigned char *base;
unsigned char *p;
const unsigned char *pe;
dns_error_t error;
size_t overflow;
}; /* struct dns_buf */
static inline size_t
dns_b_tell(struct dns_buf *b)
{
return b->p - b->base;
}
static inline dns_error_t
dns_b_setoverflow(struct dns_buf *b, size_t n, dns_error_t error)
{
b->overflow += n;
return b->error = error;
}
DNS_NOTUSED static struct dns_buf *
dns_b_into(struct dns_buf *b, void *src, size_t n)
{
*b = (struct dns_buf)DNS_B_INTO(src, n);
return b;
}
static dns_error_t
dns_b_putc(struct dns_buf *b, unsigned char uc)
{
if (!(b->p < b->pe))
return dns_b_setoverflow(b, 1, DNS_ENOBUFS);
*b->p++ = uc;
return 0;
}
static dns_error_t
dns_b_pputc(struct dns_buf *b, unsigned char uc, size_t p)
{
size_t pe = b->pe - b->base;
if (pe <= p)
return dns_b_setoverflow(b, p - pe + 1, DNS_ENOBUFS);
*((unsigned char *)b->base + p) = uc;
return 0;
}
static inline dns_error_t
dns_b_put16(struct dns_buf *b, uint16_t u)
{
return dns_b_putc(b, u >> 8), dns_b_putc(b, u >> 0);
}
static inline dns_error_t
dns_b_pput16(struct dns_buf *b, uint16_t u, size_t p)
{
if (dns_b_pputc(b, u >> 8, p) || dns_b_pputc(b, u >> 0, p + 1))
return b->error;
return 0;
}
DNS_NOTUSED static inline dns_error_t
dns_b_put32(struct dns_buf *b, uint32_t u)
{
return dns_b_putc(b, u >> 24), dns_b_putc(b, u >> 16),
dns_b_putc(b, u >> 8), dns_b_putc(b, u >> 0);
}
static dns_error_t
dns_b_put(struct dns_buf *b, const void *src, size_t len)
{
size_t n = DNS_PP_MIN((size_t)(b->pe - b->p), len);
memcpy(b->p, src, n);
b->p += n;
if (n < len)
return dns_b_setoverflow(b, len - n, DNS_ENOBUFS);
return 0;
}
static dns_error_t
dns_b_puts(struct dns_buf *b, const void *src)
{
return dns_b_put(b, src, strlen(src));
}
DNS_NOTUSED static inline dns_error_t
dns_b_fmtju(struct dns_buf *b, const uintmax_t u, const unsigned width)
{
size_t digits, padding, overflow;
uintmax_t r;
unsigned char *tp, *te, tc;
digits = 0;
r = u;
do {
digits++;
r /= 10;
} while (r);
padding = width - DNS_PP_MIN(digits, width);
overflow = (digits + padding) - DNS_PP_MIN((size_t)(b->pe - b->p), (digits + padding));
while (padding--) {
dns_b_putc(b, '0');
}
digits = 0;
tp = b->p;
r = u;
do {
if (overflow < ++digits)
dns_b_putc(b, '0' + (r % 10));
r /= 10;
} while (r);
te = b->p;
while (tp < te) {
tc = *--te;
*te = *tp;
*tp++ = tc;
}
return b->error;
}
static void
dns_b_popc(struct dns_buf *b)
{
if (b->overflow && !--b->overflow)
b->error = 0;
if (b->p > b->base)
b->p--;
}
static inline const char *
dns_b_tolstring(struct dns_buf *b, size_t *n)
{
if (b->p < b->pe) {
*b->p = '\0';
*n = b->p - b->base;
return (const char *)b->base;
} else if (b->p > b->base) {
if (b->p[-1] != '\0') {
dns_b_setoverflow(b, 1, DNS_ENOBUFS);
b->p[-1] = '\0';
}
*n = &b->p[-1] - b->base;
return (const char *)b->base;
} else {
*n = 0;
return "";
}
}
static inline const char *
dns_b_tostring(struct dns_buf *b)
{
size_t n;
return dns_b_tolstring(b, &n);
}
static inline size_t
dns_b_strlen(struct dns_buf *b)
{
size_t n;
dns_b_tolstring(b, &n);
return n;
}
static inline size_t
dns_b_strllen(struct dns_buf *b)
{
size_t n = dns_b_strlen(b);
return n + b->overflow;
}
DNS_NOTUSED static const struct dns_buf *
dns_b_from(const struct dns_buf *b, const void *src, size_t n)
{
*(struct dns_buf *)b = (struct dns_buf)DNS_B_FROM(src, n);
return b;
}
static inline int
dns_b_getc(const struct dns_buf *_b, const int eof)
{
struct dns_buf *b = (struct dns_buf *)_b;
if (!(b->p < b->pe))
return dns_b_setoverflow(b, 1, DNS_EILLEGAL), eof;
return *b->p++;
}
static inline intmax_t
dns_b_get16(const struct dns_buf *b, const intmax_t eof)
{
intmax_t n;
n = (dns_b_getc(b, 0) << 8);
n |= (dns_b_getc(b, 0) << 0);
return (!b->overflow)? n : eof;
}
DNS_NOTUSED static inline intmax_t
dns_b_get32(const struct dns_buf *b, const intmax_t eof)
{
intmax_t n;
n = (dns_b_get16(b, 0) << 16);
n |= (dns_b_get16(b, 0) << 0);
return (!b->overflow)? n : eof;
}
static inline dns_error_t
dns_b_move(struct dns_buf *dst, const struct dns_buf *_src, size_t n)
{
struct dns_buf *src = (struct dns_buf *)_src;
size_t src_n = DNS_PP_MIN((size_t)(src->pe - src->p), n);
size_t src_r = n - src_n;
dns_b_put(dst, src->p, src_n);
src->p += src_n;
if (src_r)
return dns_b_setoverflow(src, src_r, DNS_EILLEGAL);
return dst->error;
}
/*
* T I M E R O U T I N E S
*
* Most functions still rely on the older time routines defined in the
* utility routines section, above.
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_TIME_C(n) UINT64_C(n)
#define DNS_TIME_INF (~DNS_TIME_C(0))
typedef uint64_t dns_time_t;
typedef dns_time_t dns_microseconds_t;
static dns_error_t dns_time_add(dns_time_t *r, dns_time_t a, dns_time_t b) {
int error;
DNS_CHECK_OVERFLOW(&error, r, dns_add_overflow, a, b, DNS_TIME_INF);
return error;
}
static dns_error_t dns_time_mul(dns_time_t *r, dns_time_t a, dns_time_t b) {
int error;
DNS_CHECK_OVERFLOW(&error, r, dns_mul_overflow, a, b, DNS_TIME_INF);
return error;
}
static dns_error_t dns_time_diff(dns_time_t *r, dns_time_t a, dns_time_t b) {
if (a < b) {
*r = DNS_TIME_C(0);
return ERANGE;
} else {
*r = a - b;
return 0;
}
}
static dns_microseconds_t dns_ts2us(const struct timespec *ts, _Bool rup) {
if (ts) {
dns_time_t sec = DNS_PP_MAX(0, ts->tv_sec);
dns_time_t nsec = DNS_PP_MAX(0, ts->tv_nsec);
dns_time_t usec = nsec / 1000;
dns_microseconds_t r;
if (rup && nsec % 1000 > 0)
usec++;
dns_time_mul(&r, sec, DNS_TIME_C(1000000));
dns_time_add(&r, r, usec);
return r;
} else {
return DNS_TIME_INF;
}
} /* dns_ts2us() */
static struct timespec *dns_tv2ts(struct timespec *ts, const struct timeval *tv) {
if (tv) {
ts->tv_sec = tv->tv_sec;
ts->tv_nsec = tv->tv_usec * 1000;
return ts;
} else {
return NULL;
}
} /* dns_tv2ts() */
static size_t dns_utime_print(void *_dst, size_t lim, dns_microseconds_t us) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
dns_b_fmtju(&dst, us / 1000000, 1);
dns_b_putc(&dst, '.');
dns_b_fmtju(&dst, us % 1000000, 6);
return dns_b_strllen(&dst);
} /* dns_utime_print() */
/*
* P A C K E T R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
unsigned dns_p_count(struct dns_packet *P, enum dns_section section) {
unsigned count;
switch (section) {
case DNS_S_QD:
return ntohs(dns_header(P)->qdcount);
case DNS_S_AN:
return ntohs(dns_header(P)->ancount);
case DNS_S_NS:
return ntohs(dns_header(P)->nscount);
case DNS_S_AR:
return ntohs(dns_header(P)->arcount);
default:
count = 0;
if (section & DNS_S_QD)
count += ntohs(dns_header(P)->qdcount);
if (section & DNS_S_AN)
count += ntohs(dns_header(P)->ancount);
if (section & DNS_S_NS)
count += ntohs(dns_header(P)->nscount);
if (section & DNS_S_AR)
count += ntohs(dns_header(P)->arcount);
return count;
}
} /* dns_p_count() */
struct dns_packet *dns_p_init(struct dns_packet *P, size_t size) {
if (!P)
return 0;
assert(size >= offsetof(struct dns_packet, data) + 12);
memset(P, 0, sizeof *P);
P->size = size - offsetof(struct dns_packet, data);
P->end = 12;
memset(P->data, '\0', 12);
return P;
} /* dns_p_init() */
static struct dns_packet *dns_p_reset(struct dns_packet *P) {
return dns_p_init(P, offsetof(struct dns_packet, data) + P->size);
} /* dns_p_reset() */
static unsigned short dns_p_qend(struct dns_packet *P) {
unsigned short qend = 12;
unsigned i, count = dns_p_count(P, DNS_S_QD);
for (i = 0; i < count && qend < P->end; i++) {
if (P->end == (qend = dns_d_skip(qend, P)))
goto invalid;
if (P->end - qend < 4)
goto invalid;
qend += 4;
}
return DNS_PP_MIN(qend, P->end);
invalid:
return P->end;
} /* dns_p_qend() */
struct dns_packet *dns_p_make(size_t len, int *error) {
struct dns_packet *P;
size_t size = dns_p_calcsize(len);
if (!(P = dns_p_init(malloc(size), size)))
*error = dns_syerr();
return P;
} /* dns_p_make() */
static void dns_p_free(struct dns_packet *P) {
free(P);
} /* dns_p_free() */
/* convience routine to free any existing packet before storing new packet */
static struct dns_packet *dns_p_setptr(struct dns_packet **dst, struct dns_packet *src) {
dns_p_free(*dst);
*dst = src;
return src;
} /* dns_p_setptr() */
static struct dns_packet *dns_p_movptr(struct dns_packet **dst, struct dns_packet **src) {
dns_p_setptr(dst, *src);
*src = NULL;
return *dst;
} /* dns_p_movptr() */
int dns_p_grow(struct dns_packet **P) {
struct dns_packet *tmp;
size_t size;
int error;
if (!*P) {
if (!(*P = dns_p_make(DNS_P_QBUFSIZ, &error)))
return error;
return 0;
}
size = dns_p_sizeof(*P);
size |= size >> 1;
size |= size >> 2;
size |= size >> 4;
size |= size >> 8;
size++;
if (size > 65536)
return DNS_ENOBUFS;
if (!(tmp = realloc(*P, dns_p_calcsize(size))))
return dns_syerr();
tmp->size = size;
*P = tmp;
return 0;
} /* dns_p_grow() */
struct dns_packet *dns_p_copy(struct dns_packet *P, const struct dns_packet *P0) {
if (!P)
return 0;
P->end = DNS_PP_MIN(P->size, P0->end);
memcpy(P->data, P0->data, P->end);
return P;
} /* dns_p_copy() */
struct dns_packet *dns_p_merge(struct dns_packet *A, enum dns_section Amask, struct dns_packet *B, enum dns_section Bmask, int *error_) {
size_t bufsiz = DNS_PP_MIN(65535, ((A)? A->end : 0) + ((B)? B->end : 0));
struct dns_packet *M;
enum dns_section section;
struct dns_rr rr, mr;
int error, copy;
if (!A && B) {
A = B;
Amask = Bmask;
B = 0;
}
merge:
if (!(M = dns_p_make(bufsiz, &error)))
goto error;
for (section = DNS_S_QD; (DNS_S_ALL & section); section <<= 1) {
if (A && (section & Amask)) {
dns_rr_foreach(&rr, A, .section = section) {
if ((error = dns_rr_copy(M, &rr, A)))
goto error;
}
}
if (B && (section & Bmask)) {
dns_rr_foreach(&rr, B, .section = section) {
copy = 1;
dns_rr_foreach(&mr, M, .type = rr.type, .section = DNS_S_ALL) {
if (!(copy = dns_rr_cmp(&rr, B, &mr, M)))
break;
}
if (copy && (error = dns_rr_copy(M, &rr, B)))
goto error;
}
}
}
return M;
error:
dns_p_setptr(&M, NULL);
if (error == DNS_ENOBUFS && bufsiz < 65535) {
bufsiz = DNS_PP_MIN(65535, bufsiz * 2);
goto merge;
}
*error_ = error;
return 0;
} /* dns_p_merge() */
static unsigned short dns_l_skip(unsigned short, const unsigned char *, size_t);
void dns_p_dictadd(struct dns_packet *P, unsigned short dn) {
unsigned short lp, lptr, i;
lp = dn;
while (lp < P->end) {
if (0xc0 == (0xc0 & P->data[lp]) && P->end - lp >= 2 && lp != dn) {
lptr = ((0x3f & P->data[lp + 0]) << 8)
| ((0xff & P->data[lp + 1]) << 0);
for (i = 0; i < lengthof(P->dict) && P->dict[i]; i++) {
if (P->dict[i] == lptr) {
P->dict[i] = dn;
return;
}
}
}
lp = dns_l_skip(lp, P->data, P->end);
}
for (i = 0; i < lengthof(P->dict); i++) {
if (!P->dict[i]) {
P->dict[i] = dn;
break;
}
}
} /* dns_p_dictadd() */
static inline uint16_t
plus1_ns (uint16_t count_net)
{
uint16_t count = ntohs (count_net);
count++;
return htons (count);
}
int dns_p_push(struct dns_packet *P, enum dns_section section, const void *dn, size_t dnlen, enum dns_type type, enum dns_class class, unsigned ttl, const void *any) {
size_t end = P->end;
int error;
if ((error = dns_d_push(P, dn, dnlen)))
goto error;
if (P->size - P->end < 4)
goto nobufs;
P->data[P->end++] = 0xff & (type >> 8);
P->data[P->end++] = 0xff & (type >> 0);
P->data[P->end++] = 0xff & (class >> 8);
P->data[P->end++] = 0xff & (class >> 0);
if (section == DNS_S_QD)
goto update;
if (P->size - P->end < 6)
goto nobufs;
if (type != DNS_T_OPT)
ttl = DNS_PP_MIN(ttl, 0x7fffffffU);
P->data[P->end++] = ttl >> 24;
P->data[P->end++] = ttl >> 16;
P->data[P->end++] = ttl >> 8;
P->data[P->end++] = ttl >> 0;
if ((error = dns_any_push(P, (union dns_any *)any, type)))
goto error;
update:
switch (section) {
case DNS_S_QD:
if (dns_p_count(P, DNS_S_AN|DNS_S_NS|DNS_S_AR))
goto order;
if (!P->memo.qd.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->qdcount = plus1_ns (dns_header(P)->qdcount);
P->memo.qd.end = P->end;
P->memo.an.base = P->end;
P->memo.an.end = P->end;
P->memo.ns.base = P->end;
P->memo.ns.end = P->end;
P->memo.ar.base = P->end;
P->memo.ar.end = P->end;
break;
case DNS_S_AN:
if (dns_p_count(P, DNS_S_NS|DNS_S_AR))
goto order;
if (!P->memo.an.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->ancount = plus1_ns (dns_header(P)->ancount);
P->memo.an.end = P->end;
P->memo.ns.base = P->end;
P->memo.ns.end = P->end;
P->memo.ar.base = P->end;
P->memo.ar.end = P->end;
break;
case DNS_S_NS:
if (dns_p_count(P, DNS_S_AR))
goto order;
if (!P->memo.ns.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->nscount = plus1_ns (dns_header(P)->nscount);
P->memo.ns.end = P->end;
P->memo.ar.base = P->end;
P->memo.ar.end = P->end;
break;
case DNS_S_AR:
if (!P->memo.ar.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->arcount = plus1_ns (dns_header(P)->arcount);
P->memo.ar.end = P->end;
if (type == DNS_T_OPT && !P->memo.opt.p) {
P->memo.opt.p = end;
P->memo.opt.maxudp = class;
P->memo.opt.ttl = ttl;
}
break;
default:
error = DNS_ESECTION;
goto error;
} /* switch() */
return 0;
nobufs:
error = DNS_ENOBUFS;
goto error;
order:
error = DNS_EORDER;
goto error;
error:
P->end = end;
return error;
} /* dns_p_push() */
#define DNS_SM_RESTORE do { pc = state->pc; error = state->error; } while (0)
#define DNS_SM_SAVE do { state->error = error; state->pc = pc; } while (0)
struct dns_p_lines_i {
int pc;
enum dns_section section;
struct dns_rr rr;
int error;
};
static size_t dns_p_lines_fmt(void *dst, size_t lim, dns_error_t *_error, const char *fmt, ...) {
va_list ap;
int error = 0, n;
va_start(ap, fmt);
if ((n = vsnprintf(dst, lim, fmt, ap)) < 0)
error = errno;
va_end(ap);
*_error = error;
return DNS_PP_MAX(n, 0);
} /* dns_p_lines_fmt() */
#define DNS_P_LINE(...) \
do { \
len = dns_p_lines_fmt(dst, lim, &error, __VA_ARGS__); \
if (len == 0 && error) \
goto error; \
DNS_SM_YIELD(len); \
} while (0)
static size_t dns_p_lines(void *dst, size_t lim, dns_error_t *_error, struct dns_packet *P, struct dns_rr_i *I, struct dns_p_lines_i *state) {
int error, pc;
size_t len;
*_error = 0;
DNS_SM_ENTER;
DNS_P_LINE(";; [HEADER]\n");
DNS_P_LINE(";; qid : %d\n", ntohs(dns_header(P)->qid));
DNS_P_LINE(";; qr : %s(%d)\n", (dns_header(P)->qr)? "RESPONSE" : "QUERY", dns_header(P)->qr);
DNS_P_LINE(";; opcode : %s(%d)\n", dns_stropcode(dns_header(P)->opcode), dns_header(P)->opcode);
DNS_P_LINE(";; aa : %s(%d)\n", (dns_header(P)->aa)? "AUTHORITATIVE" : "NON-AUTHORITATIVE", dns_header(P)->aa);
DNS_P_LINE(";; tc : %s(%d)\n", (dns_header(P)->tc)? "TRUNCATED" : "NOT-TRUNCATED", dns_header(P)->tc);
DNS_P_LINE(";; rd : %s(%d)\n", (dns_header(P)->rd)? "RECURSION-DESIRED" : "RECURSION-NOT-DESIRED", dns_header(P)->rd);
DNS_P_LINE(";; ra : %s(%d)\n", (dns_header(P)->ra)? "RECURSION-ALLOWED" : "RECURSION-NOT-ALLOWED", dns_header(P)->ra);
DNS_P_LINE(";; rcode : %s(%d)\n", dns_strrcode(dns_p_rcode(P)), dns_p_rcode(P));
while (dns_rr_grep(&state->rr, 1, I, P, &error)) {
if (state->section != state->rr.section) {
DNS_P_LINE("\n");
DNS_P_LINE(";; [%s:%d]\n", dns_strsection(state->rr.section), dns_p_count(P, state->rr.section));
}
if (!(len = dns_rr_print(dst, lim, &state->rr, P, &error)))
goto error;
dns_strlcat(dst, "\n", lim);
DNS_SM_YIELD(len + 1);
state->section = state->rr.section;
}
if (error)
goto error;
DNS_SM_EXIT;
error:
for (;;) {
*_error = error;
DNS_SM_YIELD(0);
}
DNS_SM_LEAVE;
*_error = 0;
return 0;
} /* dns_p_lines() */
#undef DNS_P_LINE
#undef DNS_SM_SAVE
#undef DNS_SM_RESTORE
static void dns_p_dump3(struct dns_packet *P, struct dns_rr_i *I, FILE *fp) {
struct dns_p_lines_i lines = { 0 };
char line[sizeof (union dns_any) * 2];
size_t len;
int error;
while ((len = dns_p_lines(line, sizeof line, &error, P, I, &lines))) {
if (len < sizeof line) {
fwrite(line, 1, len, fp);
} else {
fwrite(line, 1, sizeof line - 1, fp);
fputc('\n', fp);
}
}
} /* dns_p_dump3() */
void dns_p_dump(struct dns_packet *P, FILE *fp) {
dns_p_dump3(P, dns_rr_i_new(P, .section = 0), fp);
} /* dns_p_dump() */
static void dns_s_unstudy(struct dns_s_memo *m)
{ m->base = 0; m->end = 0; }
static void dns_m_unstudy(struct dns_p_memo *m) {
dns_s_unstudy(&m->qd);
dns_s_unstudy(&m->an);
dns_s_unstudy(&m->ns);
dns_s_unstudy(&m->ar);
m->opt.p = 0;
m->opt.maxudp = 0;
m->opt.ttl = 0;
} /* dns_m_unstudy() */
static int dns_s_study(struct dns_s_memo *m, enum dns_section section, unsigned short base, struct dns_packet *P) {
unsigned short count, rp;
count = dns_p_count(P, section);
for (rp = base; count && rp < P->end; count--)
rp = dns_rr_skip(rp, P);
m->base = base;
m->end = rp;
return 0;
} /* dns_s_study() */
static int dns_m_study(struct dns_p_memo *m, struct dns_packet *P) {
struct dns_rr rr;
int error;
if ((error = dns_s_study(&m->qd, DNS_S_QD, 12, P)))
goto error;
if ((error = dns_s_study(&m->an, DNS_S_AN, m->qd.end, P)))
goto error;
if ((error = dns_s_study(&m->ns, DNS_S_NS, m->an.end, P)))
goto error;
if ((error = dns_s_study(&m->ar, DNS_S_AR, m->ns.end, P)))
goto error;
m->opt.p = 0;
m->opt.maxudp = 0;
m->opt.ttl = 0;
dns_rr_foreach(&rr, P, .type = DNS_T_OPT, .section = DNS_S_AR) {
m->opt.p = rr.dn.p;
m->opt.maxudp = rr.class;
m->opt.ttl = rr.ttl;
break;
}
return 0;
error:
dns_m_unstudy(m);
return error;
} /* dns_m_study() */
int dns_p_study(struct dns_packet *P) {
return dns_m_study(&P->memo, P);
} /* dns_p_study() */
enum dns_rcode dns_p_rcode(struct dns_packet *P) {
return 0xfff & ((P->memo.opt.ttl >> 20) | dns_header(P)->rcode);
} /* dns_p_rcode() */
/*
* Q U E R Y P A C K E T R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#define DNS_Q_RD 0x1 /* recursion desired */
#define DNS_Q_EDNS0 0x2 /* include OPT RR */
static dns_error_t
dns_q_make2(struct dns_packet **_Q, const char *qname, size_t qlen, enum dns_type qtype, enum dns_class qclass, int qflags)
{
struct dns_packet *Q = NULL;
int error;
if (dns_p_movptr(&Q, _Q)) {
dns_p_reset(Q);
} else if (!(Q = dns_p_make(DNS_P_QBUFSIZ, &error))) {
goto error;
}
if ((error = dns_p_push(Q, DNS_S_QD, qname, qlen, qtype, qclass, 0, 0)))
goto error;
dns_header(Q)->rd = !!(qflags & DNS_Q_RD);
if (qflags & DNS_Q_EDNS0) {
struct dns_opt opt = DNS_OPT_INIT(&opt);
opt.version = 0; /* RFC 6891 version */
opt.maxudp = 4096;
if ((error = dns_p_push(Q, DNS_S_AR, ".", 1, DNS_T_OPT, dns_opt_class(&opt), dns_opt_ttl(&opt), &opt)))
goto error;
}
*_Q = Q;
return 0;
error:
dns_p_free(Q);
return error;
}
static dns_error_t
dns_q_make(struct dns_packet **Q, const char *qname, enum dns_type qtype, enum dns_class qclass, int qflags)
{
return dns_q_make2(Q, qname, strlen(qname), qtype, qclass, qflags);
}
static dns_error_t
dns_q_remake(struct dns_packet **Q, int qflags)
{
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
struct dns_rr rr;
int error;
assert(Q && *Q);
if ((error = dns_rr_parse(&rr, 12, *Q)))
return error;
if (!(qlen = dns_d_expand(qname, sizeof qname, rr.dn.p, *Q, &error)))
return error;
if (qlen >= sizeof qname)
return DNS_EILLEGAL;
return dns_q_make2(Q, qname, qlen, rr.type, rr.class, qflags);
}
/*
* D O M A I N N A M E R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#ifndef DNS_D_MAXPTRS
#define DNS_D_MAXPTRS 127 /* Arbitrary; possible, valid depth is something like packet size / 2 + fudge. */
#endif
static size_t dns_l_expand(unsigned char *dst, size_t lim, unsigned short src, unsigned short *nxt, const unsigned char *data, size_t end) {
unsigned short len;
unsigned nptrs = 0;
retry:
if (src >= end)
goto invalid;
switch (0x03 & (data[src] >> 6)) {
case 0x00:
len = (0x3f & (data[src++]));
if (end - src < len)
goto invalid;
if (lim > 0) {
memcpy(dst, &data[src], DNS_PP_MIN(lim, len));
dst[DNS_PP_MIN(lim - 1, len)] = '\0';
}
*nxt = src + len;
return len;
case 0x01:
goto invalid;
case 0x02:
goto invalid;
case 0x03:
if (++nptrs > DNS_D_MAXPTRS)
goto invalid;
if (end - src < 2)
goto invalid;
src = ((0x3f & data[src + 0]) << 8)
| ((0xff & data[src + 1]) << 0);
goto retry;
} /* switch() */
/* NOT REACHED */
invalid:
*nxt = end;
return 0;
} /* dns_l_expand() */
static unsigned short dns_l_skip(unsigned short src, const unsigned char *data, size_t end) {
unsigned short len;
if (src >= end)
goto invalid;
switch (0x03 & (data[src] >> 6)) {
case 0x00:
len = (0x3f & (data[src++]));
if (end - src < len)
goto invalid;
return (len)? src + len : end;
case 0x01:
goto invalid;
case 0x02:
goto invalid;
case 0x03:
return end;
} /* switch() */
/* NOT REACHED */
invalid:
return end;
} /* dns_l_skip() */
static _Bool dns_d_isanchored(const void *_src, size_t len) {
const unsigned char *src = _src;
return len > 0 && src[len - 1] == '.';
} /* dns_d_isanchored() */
static size_t dns_d_ndots(const void *_src, size_t len) {
const unsigned char *p = _src, *pe = p + len;
size_t ndots = 0;
while ((p = memchr(p, '.', pe - p))) {
ndots++;
p++;
}
return ndots;
} /* dns_d_ndots() */
static size_t dns_d_trim(void *dst_, size_t lim, const void *src_, size_t len, int flags) {
unsigned char *dst = dst_;
const unsigned char *src = src_;
size_t dp = 0, sp = 0;
int lc;
/* trim any leading dot(s) */
while (sp < len && src[sp] == '.')
sp++;
for (lc = 0; sp < len; lc = src[sp++]) {
/* trim extra dot(s) */
if (src[sp] == '.' && lc == '.')
continue;
if (dp < lim)
dst[dp] = src[sp];
dp++;
}
if ((flags & DNS_D_ANCHOR) && lc != '.') {
if (dp < lim)
dst[dp] = '.';
dp++;
}
if (lim > 0)
dst[DNS_PP_MIN(dp, lim - 1)] = '\0';
return dp;
} /* dns_d_trim() */
char *dns_d_init(void *dst, size_t lim, const void *src, size_t len, int flags) {
if (flags & DNS_D_TRIM) {
dns_d_trim(dst, lim, src, len, flags);
} if (flags & DNS_D_ANCHOR) {
dns_d_anchor(dst, lim, src, len);
} else {
memmove(dst, src, DNS_PP_MIN(lim, len));
if (lim > 0)
((char *)dst)[DNS_PP_MIN(len, lim - 1)] = '\0';
}
return dst;
} /* dns_d_init() */
size_t dns_d_anchor(void *dst, size_t lim, const void *src, size_t len) {
if (len == 0)
return 0;
memmove(dst, src, DNS_PP_MIN(lim, len));
if (((const char *)src)[len - 1] != '.') {
if (len < lim)
((char *)dst)[len] = '.';
len++;
}
if (lim > 0)
((char *)dst)[DNS_PP_MIN(lim - 1, len)] = '\0';
return len;
} /* dns_d_anchor() */
size_t dns_d_cleave(void *dst, size_t lim, const void *src, size_t len) {
const char *dot;
/* XXX: Skip any leading dot. Handles cleaving root ".". */
if (len == 0 || !(dot = memchr((const char *)src + 1, '.', len - 1)))
return 0;
len -= dot - (const char *)src;
/* XXX: Unless root, skip the label's trailing dot. */
if (len > 1) {
src = ++dot;
len--;
} else
src = dot;
memmove(dst, src, DNS_PP_MIN(lim, len));
if (lim > 0)
((char *)dst)[DNS_PP_MIN(lim - 1, len)] = '\0';
return len;
} /* dns_d_cleave() */
size_t dns_d_comp(void *dst_, size_t lim, const void *src_, size_t len, struct dns_packet *P, int *error) {
struct { unsigned char *b; size_t p, x; } dst, src;
unsigned char ch = '.';
dst.b = dst_;
dst.p = 0;
dst.x = 1;
src.b = (unsigned char *)src_;
src.p = 0;
src.x = 0;
while (src.x < len) {
ch = src.b[src.x];
if (ch == '.') {
if (dst.p < lim)
dst.b[dst.p] = (0x3f & (src.x - src.p));
dst.p = dst.x++;
src.p = ++src.x;
} else {
if (dst.x < lim)
dst.b[dst.x] = ch;
dst.x++;
src.x++;
}
} /* while() */
if (src.x > src.p) {
if (dst.p < lim)
dst.b[dst.p] = (0x3f & (src.x - src.p));
dst.p = dst.x;
}
if (dst.p > 1) {
if (dst.p < lim)
dst.b[dst.p] = 0x00;
dst.p++;
}
#if 1
if (dst.p < lim) {
struct { unsigned char label[DNS_D_MAXLABEL + 1]; size_t len; unsigned short p, x, y; } a, b;
unsigned i;
a.p = 0;
while ((a.len = dns_l_expand(a.label, sizeof a.label, a.p, &a.x, dst.b, lim))) {
for (i = 0; i < lengthof(P->dict) && P->dict[i]; i++) {
b.p = P->dict[i];
while ((b.len = dns_l_expand(b.label, sizeof b.label, b.p, &b.x, P->data, P->end))) {
a.y = a.x;
b.y = b.x;
while (a.len && b.len && 0 == strcasecmp((char *)a.label, (char *)b.label)) {
a.len = dns_l_expand(a.label, sizeof a.label, a.y, &a.y, dst.b, lim);
b.len = dns_l_expand(b.label, sizeof b.label, b.y, &b.y, P->data, P->end);
}
if (a.len == 0 && b.len == 0 && b.p <= 0x3fff) {
dst.b[a.p++] = 0xc0
| (0x3f & (b.p >> 8));
dst.b[a.p++] = (0xff & (b.p >> 0));
/* silence static analyzers */
dns_assume(a.p > 0);
return a.p;
}
b.p = b.x;
} /* while() */
} /* for() */
a.p = a.x;
} /* while() */
} /* if () */
#endif
if (!dst.p)
*error = DNS_EILLEGAL;
return dst.p;
} /* dns_d_comp() */
unsigned short dns_d_skip(unsigned short src, struct dns_packet *P) {
unsigned short len;
while (src < P->end) {
switch (0x03 & (P->data[src] >> 6)) {
case 0x00: /* FOLLOWS */
len = (0x3f & P->data[src++]);
if (0 == len) {
/* success ==> */ return src;
} else if (P->end - src > len) {
src += len;
break;
} else
goto invalid;
/* NOT REACHED */
case 0x01: /* RESERVED */
goto invalid;
case 0x02: /* RESERVED */
goto invalid;
case 0x03: /* POINTER */
if (P->end - src < 2)
goto invalid;
src += 2;
/* success ==> */ return src;
} /* switch() */
} /* while() */
invalid:
return P->end;
} /* dns_d_skip() */
#include <stdio.h>
size_t dns_d_expand(void *dst, size_t lim, unsigned short src, struct dns_packet *P, int *error) {
size_t dstp = 0;
unsigned nptrs = 0;
unsigned char len;
while (src < P->end) {
switch ((0x03 & (P->data[src] >> 6))) {
case 0x00: /* FOLLOWS */
len = (0x3f & P->data[src]);
if (0 == len) {
if (dstp == 0) {
if (dstp < lim)
((unsigned char *)dst)[dstp] = '.';
dstp++;
}
/* NUL terminate */
if (lim > 0)
((unsigned char *)dst)[DNS_PP_MIN(dstp, lim - 1)] = '\0';
/* success ==> */ return dstp;
}
src++;
if (P->end - src < len)
goto toolong;
if (dstp < lim)
memcpy(&((unsigned char *)dst)[dstp], &P->data[src], DNS_PP_MIN(len, lim - dstp));
src += len;
dstp += len;
if (dstp < lim)
((unsigned char *)dst)[dstp] = '.';
dstp++;
nptrs = 0;
continue;
case 0x01: /* RESERVED */
goto reserved;
case 0x02: /* RESERVED */
goto reserved;
case 0x03: /* POINTER */
if (++nptrs > DNS_D_MAXPTRS)
goto toolong;
if (P->end - src < 2)
goto toolong;
src = ((0x3f & P->data[src + 0]) << 8)
| ((0xff & P->data[src + 1]) << 0);
continue;
} /* switch() */
} /* while() */
toolong:
*error = DNS_EILLEGAL;
if (lim > 0)
((unsigned char *)dst)[DNS_PP_MIN(dstp, lim - 1)] = '\0';
return 0;
reserved:
*error = DNS_EILLEGAL;
if (lim > 0)
((unsigned char *)dst)[DNS_PP_MIN(dstp, lim - 1)] = '\0';
return 0;
} /* dns_d_expand() */
int dns_d_push(struct dns_packet *P, const void *dn, size_t len) {
size_t lim = P->size - P->end;
unsigned dp = P->end;
int error = DNS_EILLEGAL; /* silence compiler */
len = dns_d_comp(&P->data[dp], lim, dn, len, P, &error);
if (len == 0)
return error;
if (len > lim)
return DNS_ENOBUFS;
P->end += len;
dns_p_dictadd(P, dp);
return 0;
} /* dns_d_push() */
size_t dns_d_cname(void *dst, size_t lim, const void *dn, size_t len, struct dns_packet *P, int *error_) {
char host[DNS_D_MAXNAME + 1];
struct dns_rr_i i;
struct dns_rr rr;
unsigned depth;
int error;
if (sizeof host <= dns_d_anchor(host, sizeof host, dn, len))
{ error = ENAMETOOLONG; goto error; }
for (depth = 0; depth < 7; depth++) {
dns_rr_i_init(memset(&i, 0, sizeof i), P);
i.section = DNS_S_ALL & ~DNS_S_QD;
i.name = host;
i.type = DNS_T_CNAME;
if (!dns_rr_grep(&rr, 1, &i, P, &error))
break;
if ((error = dns_cname_parse((struct dns_cname *)host, &rr, P)))
goto error;
}
return dns_strlcpy(dst, host, lim);
error:
*error_ = error;
return 0;
} /* dns_d_cname() */
/*
* R E S O U R C E R E C O R D R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
int dns_rr_copy(struct dns_packet *P, struct dns_rr *rr, struct dns_packet *Q) {
unsigned char dn[DNS_D_MAXNAME + 1];
union dns_any any;
size_t len;
int error;
if (!(len = dns_d_expand(dn, sizeof dn, rr->dn.p, Q, &error)))
return error;
else if (len >= sizeof dn)
return DNS_EILLEGAL;
if (rr->section != DNS_S_QD && (error = dns_any_parse(dns_any_init(&any, sizeof any), rr, Q)))
return error;
return dns_p_push(P, rr->section, dn, len, rr->type, rr->class, rr->ttl, &any);
} /* dns_rr_copy() */
int dns_rr_parse(struct dns_rr *rr, unsigned short src, struct dns_packet *P) {
unsigned short p = src;
if (src >= P->end)
goto invalid;
rr->dn.p = p;
rr->dn.len = (p = dns_d_skip(p, P)) - rr->dn.p;
if (P->end - p < 4)
goto invalid;
rr->type = ((0xff & P->data[p + 0]) << 8)
| ((0xff & P->data[p + 1]) << 0);
rr->class = ((0xff & P->data[p + 2]) << 8)
| ((0xff & P->data[p + 3]) << 0);
p += 4;
if (src < dns_p_qend(P)) {
rr->section = DNS_S_QUESTION;
rr->ttl = 0;
rr->rd.p = 0;
rr->rd.len = 0;
return 0;
}
if (P->end - p < 4)
goto invalid;
rr->ttl = ((0xff & P->data[p + 0]) << 24)
| ((0xff & P->data[p + 1]) << 16)
| ((0xff & P->data[p + 2]) << 8)
| ((0xff & P->data[p + 3]) << 0);
if (rr->type != DNS_T_OPT)
rr->ttl = DNS_PP_MIN(rr->ttl, 0x7fffffffU);
p += 4;
if (P->end - p < 2)
goto invalid;
rr->rd.len = ((0xff & P->data[p + 0]) << 8)
| ((0xff & P->data[p + 1]) << 0);
rr->rd.p = p + 2;
p += 2;
if (P->end - p < rr->rd.len)
goto invalid;
return 0;
invalid:
return DNS_EILLEGAL;
} /* dns_rr_parse() */
static unsigned short dns_rr_len(const unsigned short src, struct dns_packet *P) {
unsigned short rp, rdlen;
rp = dns_d_skip(src, P);
if (P->end - rp < 4)
return P->end - src;
rp += 4; /* TYPE, CLASS */
if (rp <= dns_p_qend(P))
return rp - src;
if (P->end - rp < 6)
return P->end - src;
rp += 6; /* TTL, RDLEN */
rdlen = ((0xff & P->data[rp - 2]) << 8)
| ((0xff & P->data[rp - 1]) << 0);
if (P->end - rp < rdlen)
return P->end - src;
rp += rdlen;
return rp - src;
} /* dns_rr_len() */
unsigned short dns_rr_skip(unsigned short src, struct dns_packet *P) {
return src + dns_rr_len(src, P);
} /* dns_rr_skip() */
static enum dns_section dns_rr_section(unsigned short src, struct dns_packet *P) {
enum dns_section section;
unsigned count, index;
unsigned short rp;
if (src >= P->memo.qd.base && src < P->memo.qd.end)
return DNS_S_QD;
if (src >= P->memo.an.base && src < P->memo.an.end)
return DNS_S_AN;
if (src >= P->memo.ns.base && src < P->memo.ns.end)
return DNS_S_NS;
if (src >= P->memo.ar.base && src < P->memo.ar.end)
return DNS_S_AR;
/* NOTE: Possibly bad memoization. Try it the hard-way. */
for (rp = 12, index = 0; rp < src && rp < P->end; index++)
rp = dns_rr_skip(rp, P);
section = DNS_S_QD;
count = dns_p_count(P, section);
while (index >= count && section <= DNS_S_AR) {
section <<= 1;
count += dns_p_count(P, section);
}
return DNS_S_ALL & section;
} /* dns_rr_section() */
static enum dns_type dns_rr_type(unsigned short src, struct dns_packet *P) {
struct dns_rr rr;
int error;
if ((error = dns_rr_parse(&rr, src, P)))
return 0;
return rr.type;
} /* dns_rr_type() */
int dns_rr_cmp(struct dns_rr *r0, struct dns_packet *P0, struct dns_rr *r1, struct dns_packet *P1) {
char host0[DNS_D_MAXNAME + 1], host1[DNS_D_MAXNAME + 1];
union dns_any any0, any1;
int cmp, error;
size_t len;
if ((cmp = r0->type - r1->type))
return cmp;
if ((cmp = r0->class - r1->class))
return cmp;
/*
* FIXME: Do label-by-label comparison to handle illegally long names?
*/
if (!(len = dns_d_expand(host0, sizeof host0, r0->dn.p, P0, &error))
|| len >= sizeof host0)
return -1;
if (!(len = dns_d_expand(host1, sizeof host1, r1->dn.p, P1, &error))
|| len >= sizeof host1)
return 1;
if ((cmp = strcasecmp(host0, host1)))
return cmp;
if (DNS_S_QD & (r0->section | r1->section)) {
if (r0->section == r1->section)
return 0;
return (r0->section == DNS_S_QD)? -1 : 1;
}
if ((error = dns_any_parse(&any0, r0, P0)))
return -1;
if ((error = dns_any_parse(&any1, r1, P1)))
return 1;
return dns_any_cmp(&any0, r0->type, &any1, r1->type);
} /* dns_rr_cmp() */
static _Bool dns_rr_exists(struct dns_rr *rr0, struct dns_packet *P0, struct dns_packet *P1) {
struct dns_rr rr1;
dns_rr_foreach(&rr1, P1, .section = rr0->section, .type = rr0->type) {
if (0 == dns_rr_cmp(rr0, P0, &rr1, P1))
return 1;
}
return 0;
} /* dns_rr_exists() */
static unsigned short dns_rr_offset(struct dns_rr *rr) {
return rr->dn.p;
} /* dns_rr_offset() */
static _Bool dns_rr_i_match(struct dns_rr *rr, struct dns_rr_i *i, struct dns_packet *P) {
if (i->section && !(rr->section & i->section))
return 0;
if (i->type && rr->type != i->type && i->type != DNS_T_ALL)
return 0;
if (i->class && rr->class != i->class && i->class != DNS_C_ANY)
return 0;
if (i->name) {
char dn[DNS_D_MAXNAME + 1];
size_t len;
int error;
if (!(len = dns_d_expand(dn, sizeof dn, rr->dn.p, P, &error))
|| len >= sizeof dn)
return 0;
if (0 != strcasecmp(dn, i->name))
return 0;
}
if (i->data && i->type && rr->section > DNS_S_QD) {
union dns_any rd;
int error;
if ((error = dns_any_parse(&rd, rr, P)))
return 0;
if (0 != dns_any_cmp(&rd, rr->type, i->data, i->type))
return 0;
}
return 1;
} /* dns_rr_i_match() */
static unsigned short dns_rr_i_start(struct dns_rr_i *i, struct dns_packet *P) {
unsigned short rp;
struct dns_rr r0, rr;
int error;
if ((i->section & DNS_S_QD) && P->memo.qd.base)
rp = P->memo.qd.base;
else if ((i->section & DNS_S_AN) && P->memo.an.base)
rp = P->memo.an.base;
else if ((i->section & DNS_S_NS) && P->memo.ns.base)
rp = P->memo.ns.base;
else if ((i->section & DNS_S_AR) && P->memo.ar.base)
rp = P->memo.ar.base;
else
rp = 12;
for (; rp < P->end; rp = dns_rr_skip(rp, P)) {
if ((error = dns_rr_parse(&rr, rp, P)))
continue;
rr.section = dns_rr_section(rp, P);
if (!dns_rr_i_match(&rr, i, P))
continue;
r0 = rr;
goto lower;
}
return P->end;
lower:
if (i->sort == &dns_rr_i_packet)
return dns_rr_offset(&r0);
while ((rp = dns_rr_skip(rp, P)) < P->end) {
if ((error = dns_rr_parse(&rr, rp, P)))
continue;
rr.section = dns_rr_section(rp, P);
if (!dns_rr_i_match(&rr, i, P))
continue;
if (i->sort(&rr, &r0, i, P) < 0)
r0 = rr;
}
return dns_rr_offset(&r0);
} /* dns_rr_i_start() */
static unsigned short dns_rr_i_skip(unsigned short rp, struct dns_rr_i *i, struct dns_packet *P) {
struct dns_rr r0, r1, rr;
int error;
if ((error = dns_rr_parse(&r0, rp, P)))
return P->end;
r0.section = dns_rr_section(rp, P);
rp = (i->sort == &dns_rr_i_packet)? dns_rr_skip(rp, P) : 12;
for (; rp < P->end; rp = dns_rr_skip(rp, P)) {
if ((error = dns_rr_parse(&rr, rp, P)))
continue;
rr.section = dns_rr_section(rp, P);
if (!dns_rr_i_match(&rr, i, P))
continue;
if (i->sort(&rr, &r0, i, P) <= 0)
continue;
r1 = rr;
goto lower;
}
return P->end;
lower:
if (i->sort == &dns_rr_i_packet)
return dns_rr_offset(&r1);
while ((rp = dns_rr_skip(rp, P)) < P->end) {
if ((error = dns_rr_parse(&rr, rp, P)))
continue;
rr.section = dns_rr_section(rp, P);
if (!dns_rr_i_match(&rr, i, P))
continue;
if (i->sort(&rr, &r0, i, P) <= 0)
continue;
if (i->sort(&rr, &r1, i, P) >= 0)
continue;
r1 = rr;
}
return dns_rr_offset(&r1);
} /* dns_rr_i_skip() */
int dns_rr_i_packet(struct dns_rr *a, struct dns_rr *b, struct dns_rr_i *i, struct dns_packet *P) {
(void)i;
(void)P;
return (int)a->dn.p - (int)b->dn.p;
} /* dns_rr_i_packet() */
int dns_rr_i_order(struct dns_rr *a, struct dns_rr *b, struct dns_rr_i *i, struct dns_packet *P) {
int cmp;
(void)i;
if ((cmp = a->section - b->section))
return cmp;
if (a->type != b->type)
return (int)a->dn.p - (int)b->dn.p;
return dns_rr_cmp(a, P, b, P);
} /* dns_rr_i_order() */
int dns_rr_i_shuffle(struct dns_rr *a, struct dns_rr *b, struct dns_rr_i *i, struct dns_packet *P) {
int cmp;
(void)i;
(void)P;
while (!i->state.regs[0])
i->state.regs[0] = dns_random();
if ((cmp = a->section - b->section))
return cmp;
return dns_k_shuffle16(a->dn.p, i->state.regs[0]) - dns_k_shuffle16(b->dn.p, i->state.regs[0]);
} /* dns_rr_i_shuffle() */
struct dns_rr_i *dns_rr_i_init(struct dns_rr_i *i, struct dns_packet *P) {
static const struct dns_rr_i i_initializer;
(void)P;
i->state = i_initializer.state;
i->saved = i->state;
return i;
} /* dns_rr_i_init() */
unsigned dns_rr_grep(struct dns_rr *rr, unsigned lim, struct dns_rr_i *i, struct dns_packet *P, int *error_) {
unsigned count = 0;
int error;
switch (i->state.exec) {
case 0:
if (!i->sort)
i->sort = &dns_rr_i_packet;
i->state.next = dns_rr_i_start(i, P);
i->state.exec++;
/* FALL THROUGH */
case 1:
while (count < lim && i->state.next < P->end) {
if ((error = dns_rr_parse(rr, i->state.next, P)))
goto error;
rr->section = dns_rr_section(i->state.next, P);
rr++;
count++;
i->state.count++;
i->state.next = dns_rr_i_skip(i->state.next, i, P);
} /* while() */
break;
} /* switch() */
return count;
error:
*error_ = error;
return count;
} /* dns_rr_grep() */
size_t dns_rr_print(void *_dst, size_t lim, struct dns_rr *rr, struct dns_packet *P, int *_error) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
union dns_any any;
size_t n;
int error;
if (rr->section == DNS_S_QD)
dns_b_putc(&dst, ';');
if (!(n = dns_d_expand(any.ns.host, sizeof any.ns.host, rr->dn.p, P, &error)))
goto error;
dns_b_put(&dst, any.ns.host, DNS_PP_MIN(n, sizeof any.ns.host - 1));
if (rr->section != DNS_S_QD) {
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, rr->ttl, 0);
}
dns_b_putc(&dst, ' ');
dns_b_puts(&dst, dns_strclass(rr->class));
dns_b_putc(&dst, ' ');
dns_b_puts(&dst, dns_strtype(rr->type));
if (rr->section == DNS_S_QD)
goto epilog;
dns_b_putc(&dst, ' ');
if ((error = dns_any_parse(dns_any_init(&any, sizeof any), rr, P)))
goto error;
n = dns_any_print(dst.p, dst.pe - dst.p, &any, rr->type);
dst.p += DNS_PP_MIN(n, (size_t)(dst.pe - dst.p));
epilog:
return dns_b_strllen(&dst);
error:
*_error = error;
return 0;
} /* dns_rr_print() */
int dns_a_parse(struct dns_a *a, struct dns_rr *rr, struct dns_packet *P) {
unsigned long addr;
if (rr->rd.len != 4)
return DNS_EILLEGAL;
addr = ((0xffU & P->data[rr->rd.p + 0]) << 24)
| ((0xffU & P->data[rr->rd.p + 1]) << 16)
| ((0xffU & P->data[rr->rd.p + 2]) << 8)
| ((0xffU & P->data[rr->rd.p + 3]) << 0);
a->addr.s_addr = htonl(addr);
return 0;
} /* dns_a_parse() */
int dns_a_push(struct dns_packet *P, struct dns_a *a) {
unsigned long addr;
if (P->size - P->end < 6)
return DNS_ENOBUFS;
P->data[P->end++] = 0x00;
P->data[P->end++] = 0x04;
addr = ntohl(a->addr.s_addr);
P->data[P->end++] = 0xffU & (addr >> 24);
P->data[P->end++] = 0xffU & (addr >> 16);
P->data[P->end++] = 0xffU & (addr >> 8);
P->data[P->end++] = 0xffU & (addr >> 0);
return 0;
} /* dns_a_push() */
size_t dns_a_arpa(void *_dst, size_t lim, const struct dns_a *a) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned long octets = ntohl(a->addr.s_addr);
unsigned i;
for (i = 0; i < 4; i++) {
dns_b_fmtju(&dst, 0xff & octets, 0);
dns_b_putc(&dst, '.');
octets >>= 8;
}
dns_b_puts(&dst, "in-addr.arpa.");
return dns_b_strllen(&dst);
} /* dns_a_arpa() */
int dns_a_cmp(const struct dns_a *a, const struct dns_a *b) {
if (ntohl(a->addr.s_addr) < ntohl(b->addr.s_addr))
return -1;
if (ntohl(a->addr.s_addr) > ntohl(b->addr.s_addr))
return 1;
return 0;
} /* dns_a_cmp() */
size_t dns_a_print(void *dst, size_t lim, struct dns_a *a) {
char addr[INET_ADDRSTRLEN + 1] = "0.0.0.0";
dns_inet_ntop(AF_INET, &a->addr, addr, sizeof addr);
return dns_strlcpy(dst, addr, lim);
} /* dns_a_print() */
int dns_aaaa_parse(struct dns_aaaa *aaaa, struct dns_rr *rr, struct dns_packet *P) {
if (rr->rd.len != sizeof aaaa->addr.s6_addr)
return DNS_EILLEGAL;
memcpy(aaaa->addr.s6_addr, &P->data[rr->rd.p], sizeof aaaa->addr.s6_addr);
return 0;
} /* dns_aaaa_parse() */
int dns_aaaa_push(struct dns_packet *P, struct dns_aaaa *aaaa) {
if (P->size - P->end < 2 + sizeof aaaa->addr.s6_addr)
return DNS_ENOBUFS;
P->data[P->end++] = 0x00;
P->data[P->end++] = 0x10;
memcpy(&P->data[P->end], aaaa->addr.s6_addr, sizeof aaaa->addr.s6_addr);
P->end += sizeof aaaa->addr.s6_addr;
return 0;
} /* dns_aaaa_push() */
int dns_aaaa_cmp(const struct dns_aaaa *a, const struct dns_aaaa *b) {
unsigned i;
int cmp;
for (i = 0; i < lengthof(a->addr.s6_addr); i++) {
if ((cmp = (a->addr.s6_addr[i] - b->addr.s6_addr[i])))
return cmp;
}
return 0;
} /* dns_aaaa_cmp() */
size_t dns_aaaa_arpa(void *_dst, size_t lim, const struct dns_aaaa *aaaa) {
static const unsigned char hex[16] = "0123456789abcdef";
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned nyble;
int i, j;
for (i = sizeof aaaa->addr.s6_addr - 1; i >= 0; i--) {
nyble = aaaa->addr.s6_addr[i];
for (j = 0; j < 2; j++) {
dns_b_putc(&dst, hex[0x0f & nyble]);
dns_b_putc(&dst, '.');
nyble >>= 4;
}
}
dns_b_puts(&dst, "ip6.arpa.");
return dns_b_strllen(&dst);
} /* dns_aaaa_arpa() */
size_t dns_aaaa_print(void *dst, size_t lim, struct dns_aaaa *aaaa) {
char addr[INET6_ADDRSTRLEN + 1] = "::";
dns_inet_ntop(AF_INET6, &aaaa->addr, addr, sizeof addr);
return dns_strlcpy(dst, addr, lim);
} /* dns_aaaa_print() */
int dns_mx_parse(struct dns_mx *mx, struct dns_rr *rr, struct dns_packet *P) {
size_t len;
int error;
if (rr->rd.len < 3)
return DNS_EILLEGAL;
mx->preference = (0xff00 & (P->data[rr->rd.p + 0] << 8))
| (0x00ff & (P->data[rr->rd.p + 1] << 0));
if (!(len = dns_d_expand(mx->host, sizeof mx->host, rr->rd.p + 2, P, &error)))
return error;
else if (len >= sizeof mx->host)
return DNS_EILLEGAL;
return 0;
} /* dns_mx_parse() */
int dns_mx_push(struct dns_packet *P, struct dns_mx *mx) {
size_t end, len;
int error;
if (P->size - P->end < 5)
return DNS_ENOBUFS;
end = P->end;
P->end += 2;
P->data[P->end++] = 0xff & (mx->preference >> 8);
P->data[P->end++] = 0xff & (mx->preference >> 0);
if ((error = dns_d_push(P, mx->host, strlen(mx->host))))
goto error;
len = P->end - end - 2;
P->data[end + 0] = 0xff & (len >> 8);
P->data[end + 1] = 0xff & (len >> 0);
return 0;
error:
P->end = end;
return error;
} /* dns_mx_push() */
int dns_mx_cmp(const struct dns_mx *a, const struct dns_mx *b) {
int cmp;
if ((cmp = a->preference - b->preference))
return cmp;
return strcasecmp(a->host, b->host);
} /* dns_mx_cmp() */
size_t dns_mx_print(void *_dst, size_t lim, struct dns_mx *mx) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
dns_b_fmtju(&dst, mx->preference, 0);
dns_b_putc(&dst, ' ');
dns_b_puts(&dst, mx->host);
return dns_b_strllen(&dst);
} /* dns_mx_print() */
size_t dns_mx_cname(void *dst, size_t lim, struct dns_mx *mx) {
return dns_strlcpy(dst, mx->host, lim);
} /* dns_mx_cname() */
int dns_ns_parse(struct dns_ns *ns, struct dns_rr *rr, struct dns_packet *P) {
size_t len;
int error;
if (!(len = dns_d_expand(ns->host, sizeof ns->host, rr->rd.p, P, &error)))
return error;
else if (len >= sizeof ns->host)
return DNS_EILLEGAL;
return 0;
} /* dns_ns_parse() */
int dns_ns_push(struct dns_packet *P, struct dns_ns *ns) {
size_t end, len;
int error;
if (P->size - P->end < 3)
return DNS_ENOBUFS;
end = P->end;
P->end += 2;
if ((error = dns_d_push(P, ns->host, strlen(ns->host))))
goto error;
len = P->end - end - 2;
P->data[end + 0] = 0xff & (len >> 8);
P->data[end + 1] = 0xff & (len >> 0);
return 0;
error:
P->end = end;
return error;
} /* dns_ns_push() */
int dns_ns_cmp(const struct dns_ns *a, const struct dns_ns *b) {
return strcasecmp(a->host, b->host);
} /* dns_ns_cmp() */
size_t dns_ns_print(void *dst, size_t lim, struct dns_ns *ns) {
return dns_strlcpy(dst, ns->host, lim);
} /* dns_ns_print() */
size_t dns_ns_cname(void *dst, size_t lim, struct dns_ns *ns) {
return dns_strlcpy(dst, ns->host, lim);
} /* dns_ns_cname() */
int dns_cname_parse(struct dns_cname *cname, struct dns_rr *rr, struct dns_packet *P) {
return dns_ns_parse((struct dns_ns *)cname, rr, P);
} /* dns_cname_parse() */
int dns_cname_push(struct dns_packet *P, struct dns_cname *cname) {
return dns_ns_push(P, (struct dns_ns *)cname);
} /* dns_cname_push() */
int dns_cname_cmp(const struct dns_cname *a, const struct dns_cname *b) {
return strcasecmp(a->host, b->host);
} /* dns_cname_cmp() */
size_t dns_cname_print(void *dst, size_t lim, struct dns_cname *cname) {
return dns_ns_print(dst, lim, (struct dns_ns *)cname);
} /* dns_cname_print() */
size_t dns_cname_cname(void *dst, size_t lim, struct dns_cname *cname) {
return dns_strlcpy(dst, cname->host, lim);
} /* dns_cname_cname() */
int dns_soa_parse(struct dns_soa *soa, struct dns_rr *rr, struct dns_packet *P) {
struct { void *dst; size_t lim; } dn[] =
{ { soa->mname, sizeof soa->mname },
{ soa->rname, sizeof soa->rname } };
unsigned *ts[] =
{ &soa->serial, &soa->refresh, &soa->retry, &soa->expire, &soa->minimum };
unsigned short rp;
unsigned i, j, n;
int error;
/* MNAME / RNAME */
if ((rp = rr->rd.p) >= P->end)
return DNS_EILLEGAL;
for (i = 0; i < lengthof(dn); i++) {
if (!(n = dns_d_expand(dn[i].dst, dn[i].lim, rp, P, &error)))
return error;
else if (n >= dn[i].lim)
return DNS_EILLEGAL;
if ((rp = dns_d_skip(rp, P)) >= P->end)
return DNS_EILLEGAL;
}
/* SERIAL / REFRESH / RETRY / EXPIRE / MINIMUM */
for (i = 0; i < lengthof(ts); i++) {
for (j = 0; j < 4; j++, rp++) {
if (rp >= P->end)
return DNS_EILLEGAL;
*ts[i] <<= 8;
*ts[i] |= (0xff & P->data[rp]);
}
}
return 0;
} /* dns_soa_parse() */
int dns_soa_push(struct dns_packet *P, struct dns_soa *soa) {
void *dn[] = { soa->mname, soa->rname };
unsigned ts[] = { (0xffffffff & soa->serial),
(0x7fffffff & soa->refresh),
(0x7fffffff & soa->retry),
(0x7fffffff & soa->expire),
(0xffffffff & soa->minimum) };
unsigned i, j;
size_t end, len;
int error;
end = P->end;
if ((P->end += 2) >= P->size)
goto toolong;
/* MNAME / RNAME */
for (i = 0; i < lengthof(dn); i++) {
if ((error = dns_d_push(P, dn[i], strlen(dn[i]))))
goto error;
}
/* SERIAL / REFRESH / RETRY / EXPIRE / MINIMUM */
for (i = 0; i < lengthof(ts); i++) {
if ((P->end += 4) >= P->size)
goto toolong;
for (j = 1; j <= 4; j++) {
P->data[P->end - j] = (0xff & ts[i]);
ts[i] >>= 8;
}
}
len = P->end - end - 2;
P->data[end + 0] = (0xff & (len >> 8));
P->data[end + 1] = (0xff & (len >> 0));
return 0;
toolong:
error = DNS_ENOBUFS;
/* FALL THROUGH */
error:
P->end = end;
return error;
} /* dns_soa_push() */
int dns_soa_cmp(const struct dns_soa *a, const struct dns_soa *b) {
int cmp;
if ((cmp = strcasecmp(a->mname, b->mname)))
return cmp;
if ((cmp = strcasecmp(a->rname, b->rname)))
return cmp;
if (a->serial > b->serial)
return -1;
else if (a->serial < b->serial)
return 1;
if (a->refresh > b->refresh)
return -1;
else if (a->refresh < b->refresh)
return 1;
if (a->retry > b->retry)
return -1;
else if (a->retry < b->retry)
return 1;
if (a->expire > b->expire)
return -1;
else if (a->expire < b->expire)
return 1;
if (a->minimum > b->minimum)
return -1;
else if (a->minimum < b->minimum)
return 1;
return 0;
} /* dns_soa_cmp() */
size_t dns_soa_print(void *_dst, size_t lim, struct dns_soa *soa) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
dns_b_puts(&dst, soa->mname);
dns_b_putc(&dst, ' ');
dns_b_puts(&dst, soa->rname);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, soa->serial, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, soa->refresh, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, soa->retry, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, soa->expire, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, soa->minimum, 0);
return dns_b_strllen(&dst);
} /* dns_soa_print() */
int dns_srv_parse(struct dns_srv *srv, struct dns_rr *rr, struct dns_packet *P) {
unsigned short rp;
unsigned i;
size_t n;
int error;
memset(srv, '\0', sizeof *srv);
rp = rr->rd.p;
if (rr->rd.len < 7)
return DNS_EILLEGAL;
for (i = 0; i < 2; i++, rp++) {
srv->priority <<= 8;
srv->priority |= (0xff & P->data[rp]);
}
for (i = 0; i < 2; i++, rp++) {
srv->weight <<= 8;
srv->weight |= (0xff & P->data[rp]);
}
for (i = 0; i < 2; i++, rp++) {
srv->port <<= 8;
srv->port |= (0xff & P->data[rp]);
}
if (!(n = dns_d_expand(srv->target, sizeof srv->target, rp, P, &error)))
return error;
else if (n >= sizeof srv->target)
return DNS_EILLEGAL;
return 0;
} /* dns_srv_parse() */
int dns_srv_push(struct dns_packet *P, struct dns_srv *srv) {
size_t end, len;
int error;
end = P->end;
if (P->size - P->end < 2)
goto toolong;
P->end += 2;
if (P->size - P->end < 6)
goto toolong;
P->data[P->end++] = 0xff & (srv->priority >> 8);
P->data[P->end++] = 0xff & (srv->priority >> 0);
P->data[P->end++] = 0xff & (srv->weight >> 8);
P->data[P->end++] = 0xff & (srv->weight >> 0);
P->data[P->end++] = 0xff & (srv->port >> 8);
P->data[P->end++] = 0xff & (srv->port >> 0);
if (0 == (len = dns_d_comp(&P->data[P->end], P->size - P->end, srv->target, strlen(srv->target), P, &error)))
goto error;
else if (P->size - P->end < len)
goto toolong;
P->end += len;
if (P->end > 65535)
goto toolong;
len = P->end - end - 2;
P->data[end + 0] = 0xff & (len >> 8);
P->data[end + 1] = 0xff & (len >> 0);
return 0;
toolong:
error = DNS_ENOBUFS;
/* FALL THROUGH */
error:
P->end = end;
return error;
} /* dns_srv_push() */
int dns_srv_cmp(const struct dns_srv *a, const struct dns_srv *b) {
int cmp;
if ((cmp = a->priority - b->priority))
return cmp;
/*
* FIXME: We need some sort of random seed to implement the dynamic
* weighting required by RFC 2782.
*/
if ((cmp = a->weight - b->weight))
return cmp;
if ((cmp = a->port - b->port))
return cmp;
return strcasecmp(a->target, b->target);
} /* dns_srv_cmp() */
size_t dns_srv_print(void *_dst, size_t lim, struct dns_srv *srv) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
dns_b_fmtju(&dst, srv->priority, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, srv->weight, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, srv->port, 0);
dns_b_putc(&dst, ' ');
dns_b_puts(&dst, srv->target);
return dns_b_strllen(&dst);
} /* dns_srv_print() */
size_t dns_srv_cname(void *dst, size_t lim, struct dns_srv *srv) {
return dns_strlcpy(dst, srv->target, lim);
} /* dns_srv_cname() */
unsigned int dns_opt_ttl(const struct dns_opt *opt) {
unsigned int ttl = 0;
ttl |= (0xffU & opt->rcode) << 24;
ttl |= (0xffU & opt->version) << 16;
ttl |= (0xffffU & opt->flags) << 0;
return ttl;
} /* dns_opt_ttl() */
unsigned short dns_opt_class(const struct dns_opt *opt) {
return opt->maxudp;
} /* dns_opt_class() */
struct dns_opt *dns_opt_init(struct dns_opt *opt, size_t size) {
assert(size >= offsetof(struct dns_opt, data));
opt->size = size - offsetof(struct dns_opt, data);
opt->len = 0;
opt->rcode = 0;
opt->version = 0;
opt->maxudp = 0;
return opt;
} /* dns_opt_init() */
static union dns_any *dns_opt_initany(union dns_any *any, size_t size) {
return dns_opt_init(&any->opt, size), any;
} /* dns_opt_initany() */
int dns_opt_parse(struct dns_opt *opt, struct dns_rr *rr, struct dns_packet *P) {
const struct dns_buf src = DNS_B_FROM(&P->data[rr->rd.p], rr->rd.len);
struct dns_buf dst = DNS_B_INTO(opt->data, opt->size);
int error;
opt->rcode = 0xfff & ((rr->ttl >> 20) | dns_header(P)->rcode);
opt->version = 0xff & (rr->ttl >> 16);
opt->flags = 0xffff & rr->ttl;
opt->maxudp = 0xffff & rr->class;
while (src.p < src.pe) {
int code, len;
if (-1 == (code = dns_b_get16(&src, -1)))
return src.error;
if (-1 == (len = dns_b_get16(&src, -1)))
return src.error;
switch (code) {
default:
dns_b_put16(&dst, code);
dns_b_put16(&dst, len);
if ((error = dns_b_move(&dst, &src, len)))
return error;
break;
}
}
return 0;
} /* dns_opt_parse() */
int dns_opt_push(struct dns_packet *P, struct dns_opt *opt) {
const struct dns_buf src = DNS_B_FROM(opt->data, opt->len);
struct dns_buf dst = DNS_B_INTO(&P->data[P->end], (P->size - P->end));
int error;
/* rdata length (see below) */
if ((error = dns_b_put16(&dst, 0)))
goto error;
/* ... push known options here */
/* push opaque option data */
if ((error = dns_b_move(&dst, &src, (size_t)(src.pe - src.p))))
goto error;
/* rdata length */
if ((error = dns_b_pput16(&dst, dns_b_tell(&dst) - 2, 0)))
goto error;
#if !DNS_DEBUG_OPT_FORMERR
P->end += dns_b_tell(&dst);
#endif
return 0;
error:
return error;
} /* dns_opt_push() */
int dns_opt_cmp(const struct dns_opt *a, const struct dns_opt *b) {
(void)a;
(void)b;
return -1;
} /* dns_opt_cmp() */
size_t dns_opt_print(void *_dst, size_t lim, struct dns_opt *opt) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
size_t p;
dns_b_putc(&dst, '"');
for (p = 0; p < opt->len; p++) {
dns_b_putc(&dst, '\\');
dns_b_fmtju(&dst, opt->data[p], 3);
}
dns_b_putc(&dst, '"');
return dns_b_strllen(&dst);
} /* dns_opt_print() */
int dns_ptr_parse(struct dns_ptr *ptr, struct dns_rr *rr, struct dns_packet *P) {
return dns_ns_parse((struct dns_ns *)ptr, rr, P);
} /* dns_ptr_parse() */
int dns_ptr_push(struct dns_packet *P, struct dns_ptr *ptr) {
return dns_ns_push(P, (struct dns_ns *)ptr);
} /* dns_ptr_push() */
size_t dns_ptr_qname(void *dst, size_t lim, int af, void *addr) {
switch (af) {
case AF_INET6:
return dns_aaaa_arpa(dst, lim, addr);
case AF_INET:
return dns_a_arpa(dst, lim, addr);
default: {
struct dns_a a;
a.addr.s_addr = INADDR_NONE;
return dns_a_arpa(dst, lim, &a);
}
}
} /* dns_ptr_qname() */
int dns_ptr_cmp(const struct dns_ptr *a, const struct dns_ptr *b) {
return strcasecmp(a->host, b->host);
} /* dns_ptr_cmp() */
size_t dns_ptr_print(void *dst, size_t lim, struct dns_ptr *ptr) {
return dns_ns_print(dst, lim, (struct dns_ns *)ptr);
} /* dns_ptr_print() */
size_t dns_ptr_cname(void *dst, size_t lim, struct dns_ptr *ptr) {
return dns_strlcpy(dst, ptr->host, lim);
} /* dns_ptr_cname() */
int dns_sshfp_parse(struct dns_sshfp *fp, struct dns_rr *rr, struct dns_packet *P) {
unsigned p = rr->rd.p, pe = rr->rd.p + rr->rd.len;
if (pe - p < 2)
return DNS_EILLEGAL;
fp->algo = P->data[p++];
fp->type = P->data[p++];
switch (fp->type) {
case DNS_SSHFP_SHA1:
if (pe - p < sizeof fp->digest.sha1)
return DNS_EILLEGAL;
memcpy(fp->digest.sha1, &P->data[p], sizeof fp->digest.sha1);
break;
default:
break;
} /* switch() */
return 0;
} /* dns_sshfp_parse() */
int dns_sshfp_push(struct dns_packet *P, struct dns_sshfp *fp) {
unsigned p = P->end, pe = P->size, n;
if (pe - p < 4)
return DNS_ENOBUFS;
p += 2;
P->data[p++] = 0xff & fp->algo;
P->data[p++] = 0xff & fp->type;
switch (fp->type) {
case DNS_SSHFP_SHA1:
if (pe - p < sizeof fp->digest.sha1)
return DNS_ENOBUFS;
memcpy(&P->data[p], fp->digest.sha1, sizeof fp->digest.sha1);
p += sizeof fp->digest.sha1;
break;
default:
return DNS_EILLEGAL;
} /* switch() */
n = p - P->end - 2;
P->data[P->end++] = 0xff & (n >> 8);
P->data[P->end++] = 0xff & (n >> 0);
P->end = p;
return 0;
} /* dns_sshfp_push() */
int dns_sshfp_cmp(const struct dns_sshfp *a, const struct dns_sshfp *b) {
int cmp;
if ((cmp = a->algo - b->algo) || (cmp = a->type - b->type))
return cmp;
switch (a->type) {
case DNS_SSHFP_SHA1:
return memcmp(a->digest.sha1, b->digest.sha1, sizeof a->digest.sha1);
default:
return 0;
} /* switch() */
/* NOT REACHED */
} /* dns_sshfp_cmp() */
size_t dns_sshfp_print(void *_dst, size_t lim, struct dns_sshfp *fp) {
static const unsigned char hex[16] = "0123456789abcdef";
struct dns_buf dst = DNS_B_INTO(_dst, lim);
size_t i;
dns_b_fmtju(&dst, fp->algo, 0);
dns_b_putc(&dst, ' ');
dns_b_fmtju(&dst, fp->type, 0);
dns_b_putc(&dst, ' ');
switch (fp->type) {
case DNS_SSHFP_SHA1:
for (i = 0; i < sizeof fp->digest.sha1; i++) {
dns_b_putc(&dst, hex[0x0f & (fp->digest.sha1[i] >> 4)]);
dns_b_putc(&dst, hex[0x0f & (fp->digest.sha1[i] >> 0)]);
}
break;
default:
dns_b_putc(&dst, '0');
break;
} /* switch() */
return dns_b_strllen(&dst);
} /* dns_sshfp_print() */
struct dns_txt *dns_txt_init(struct dns_txt *txt, size_t size) {
assert(size > offsetof(struct dns_txt, data));
txt->size = size - offsetof(struct dns_txt, data);
txt->len = 0;
return txt;
} /* dns_txt_init() */
static union dns_any *dns_txt_initany(union dns_any *any, size_t size) {
/* NB: union dns_any is already initialized as struct dns_txt */
(void)size;
return any;
} /* dns_txt_initany() */
int dns_txt_parse(struct dns_txt *txt, struct dns_rr *rr, struct dns_packet *P) {
struct { unsigned char *b; size_t p, end; } dst, src;
unsigned n;
dst.b = txt->data;
dst.p = 0;
dst.end = txt->size;
src.b = P->data;
src.p = rr->rd.p;
src.end = src.p + rr->rd.len;
while (src.p < src.end) {
n = 0xff & P->data[src.p++];
if (src.end - src.p < n || dst.end - dst.p < n)
return DNS_EILLEGAL;
memcpy(&dst.b[dst.p], &src.b[src.p], n);
dst.p += n;
src.p += n;
}
txt->len = dst.p;
return 0;
} /* dns_txt_parse() */
int dns_txt_push(struct dns_packet *P, struct dns_txt *txt) {
struct { unsigned char *b; size_t p, end; } dst, src;
unsigned n;
dst.b = P->data;
dst.p = P->end;
dst.end = P->size;
src.b = txt->data;
src.p = 0;
src.end = txt->len;
if (dst.end - dst.p < 2)
return DNS_ENOBUFS;
n = txt->len + ((txt->len + 254) / 255);
dst.b[dst.p++] = 0xff & (n >> 8);
dst.b[dst.p++] = 0xff & (n >> 0);
while (src.p < src.end) {
n = DNS_PP_MIN(255, src.end - src.p);
if (dst.p >= dst.end)
return DNS_ENOBUFS;
dst.b[dst.p++] = n;
if (dst.end - dst.p < n)
return DNS_ENOBUFS;
memcpy(&dst.b[dst.p], &src.b[src.p], n);
dst.p += n;
src.p += n;
}
P->end = dst.p;
return 0;
} /* dns_txt_push() */
int dns_txt_cmp(const struct dns_txt *a, const struct dns_txt *b) {
(void)a;
(void)b;
return -1;
} /* dns_txt_cmp() */
size_t dns_txt_print(void *_dst, size_t lim, struct dns_txt *txt) {
struct dns_buf src = DNS_B_FROM(txt->data, txt->len);
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned i;
if (src.p < src.pe) {
do {
dns_b_putc(&dst, '"');
for (i = 0; i < 256 && src.p < src.pe; i++, src.p++) {
if (*src.p < 32 || *src.p > 126 || *src.p == '"' || *src.p == '\\') {
dns_b_putc(&dst, '\\');
dns_b_fmtju(&dst, *src.p, 3);
} else {
dns_b_putc(&dst, *src.p);
}
}
dns_b_putc(&dst, '"');
dns_b_putc(&dst, ' ');
} while (src.p < src.pe);
dns_b_popc(&dst);
} else {
dns_b_putc(&dst, '"');
dns_b_putc(&dst, '"');
}
return dns_b_strllen(&dst);
} /* dns_txt_print() */
/* Some of the function pointers of DNS_RRTYPES are initialized with
* slighlly different functions, thus we can't use prototypes. */
DNS_PRAGMA_PUSH
#if __clang__
#pragma clang diagnostic ignored "-Wstrict-prototypes"
#elif DNS_GNUC_PREREQ(4,6,0)
#pragma GCC diagnostic ignored "-Wstrict-prototypes"
#endif
static const struct dns_rrtype {
enum dns_type type;
const char *name;
union dns_any *(*init)(union dns_any *, size_t);
int (*parse)();
int (*push)();
int (*cmp)();
size_t (*print)();
size_t (*cname)();
} dns_rrtypes[] = {
{ DNS_T_A, "A", 0, &dns_a_parse, &dns_a_push, &dns_a_cmp, &dns_a_print, 0, },
{ DNS_T_AAAA, "AAAA", 0, &dns_aaaa_parse, &dns_aaaa_push, &dns_aaaa_cmp, &dns_aaaa_print, 0, },
{ DNS_T_MX, "MX", 0, &dns_mx_parse, &dns_mx_push, &dns_mx_cmp, &dns_mx_print, &dns_mx_cname, },
{ DNS_T_NS, "NS", 0, &dns_ns_parse, &dns_ns_push, &dns_ns_cmp, &dns_ns_print, &dns_ns_cname, },
{ DNS_T_CNAME, "CNAME", 0, &dns_cname_parse, &dns_cname_push, &dns_cname_cmp, &dns_cname_print, &dns_cname_cname, },
{ DNS_T_SOA, "SOA", 0, &dns_soa_parse, &dns_soa_push, &dns_soa_cmp, &dns_soa_print, 0, },
{ DNS_T_SRV, "SRV", 0, &dns_srv_parse, &dns_srv_push, &dns_srv_cmp, &dns_srv_print, &dns_srv_cname, },
{ DNS_T_OPT, "OPT", &dns_opt_initany, &dns_opt_parse, &dns_opt_push, &dns_opt_cmp, &dns_opt_print, 0, },
{ DNS_T_PTR, "PTR", 0, &dns_ptr_parse, &dns_ptr_push, &dns_ptr_cmp, &dns_ptr_print, &dns_ptr_cname, },
{ DNS_T_TXT, "TXT", &dns_txt_initany, &dns_txt_parse, &dns_txt_push, &dns_txt_cmp, &dns_txt_print, 0, },
{ DNS_T_SPF, "SPF", &dns_txt_initany, &dns_txt_parse, &dns_txt_push, &dns_txt_cmp, &dns_txt_print, 0, },
{ DNS_T_SSHFP, "SSHFP", 0, &dns_sshfp_parse, &dns_sshfp_push, &dns_sshfp_cmp, &dns_sshfp_print, 0, },
{ DNS_T_AXFR, "AXFR", 0, 0, 0, 0, 0, 0, },
}; /* dns_rrtypes[] */
DNS_PRAGMA_POP /*(-Wstrict-prototypes)*/
static const struct dns_rrtype *dns_rrtype(enum dns_type type) {
const struct dns_rrtype *t;
for (t = dns_rrtypes; t < endof(dns_rrtypes); t++) {
if (t->type == type && t->parse) {
return t;
}
}
return NULL;
} /* dns_rrtype() */
union dns_any *dns_any_init(union dns_any *any, size_t size) {
dns_static_assert(dns_same_type(any->txt, any->rdata, 1), "unexpected rdata type");
return (union dns_any *)dns_txt_init(&any->rdata, size);
} /* dns_any_init() */
static size_t dns_any_sizeof(union dns_any *any) {
dns_static_assert(dns_same_type(any->txt, any->rdata, 1), "unexpected rdata type");
return offsetof(struct dns_txt, data) + any->rdata.size;
} /* dns_any_sizeof() */
static union dns_any *dns_any_reinit(union dns_any *any, const struct dns_rrtype *t) {
return (t->init)? t->init(any, dns_any_sizeof(any)) : any;
} /* dns_any_reinit() */
int dns_any_parse(union dns_any *any, struct dns_rr *rr, struct dns_packet *P) {
const struct dns_rrtype *t;
if ((t = dns_rrtype(rr->type)))
return t->parse(dns_any_reinit(any, t), rr, P);
if (rr->rd.len > any->rdata.size)
return DNS_EILLEGAL;
memcpy(any->rdata.data, &P->data[rr->rd.p], rr->rd.len);
any->rdata.len = rr->rd.len;
return 0;
} /* dns_any_parse() */
int dns_any_push(struct dns_packet *P, union dns_any *any, enum dns_type type) {
const struct dns_rrtype *t;
if ((t = dns_rrtype(type)))
return t->push(P, any);
if (P->size - P->end < any->rdata.len + 2)
return DNS_ENOBUFS;
P->data[P->end++] = 0xff & (any->rdata.len >> 8);
P->data[P->end++] = 0xff & (any->rdata.len >> 0);
memcpy(&P->data[P->end], any->rdata.data, any->rdata.len);
P->end += any->rdata.len;
return 0;
} /* dns_any_push() */
int dns_any_cmp(const union dns_any *a, enum dns_type x, const union dns_any *b, enum dns_type y) {
const struct dns_rrtype *t;
int cmp;
if ((cmp = x - y))
return cmp;
if ((t = dns_rrtype(x)))
return t->cmp(a, b);
return -1;
} /* dns_any_cmp() */
size_t dns_any_print(void *_dst, size_t lim, union dns_any *any, enum dns_type type) {
const struct dns_rrtype *t;
struct dns_buf src, dst;
if ((t = dns_rrtype(type)))
return t->print(_dst, lim, any);
dns_b_from(&src, any->rdata.data, any->rdata.len);
dns_b_into(&dst, _dst, lim);
dns_b_putc(&dst, '"');
while (src.p < src.pe) {
dns_b_putc(&dst, '\\');
dns_b_fmtju(&dst, *src.p++, 3);
}
dns_b_putc(&dst, '"');
return dns_b_strllen(&dst);
} /* dns_any_print() */
size_t dns_any_cname(void *dst, size_t lim, union dns_any *any, enum dns_type type) {
const struct dns_rrtype *t;
if ((t = dns_rrtype(type)) && t->cname)
return t->cname(dst, lim, any);
return 0;
} /* dns_any_cname() */
/*
* E V E N T T R A C I N G R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include <float.h> /* DBL_MANT_DIG */
#include <inttypes.h> /* PRIu64 */
/* for default trace ID generation try to fit in lua_Number, usually double */
#define DNS_TRACE_ID_BITS DNS_PP_MIN(DBL_MANT_DIG, (sizeof (dns_trace_id_t) * CHAR_BIT)) /* assuming FLT_RADIX == 2 */
#define DNS_TRACE_ID_MASK (((DNS_TRACE_ID_C(1) << (DNS_TRACE_ID_BITS - 1)) - 1) | (DNS_TRACE_ID_C(1) << (DNS_TRACE_ID_BITS - 1)))
#define DNS_TRACE_ID_PRI PRIu64
static inline dns_trace_id_t dns_trace_mkid(void) {
dns_trace_id_t id = 0;
unsigned r; /* return type of dns_random() */
const size_t id_bit = sizeof id * CHAR_BIT;
const size_t r_bit = sizeof r * CHAR_BIT;
for (size_t n = 0; n < id_bit; n += r_bit) {
r = dns_random();
id <<= r_bit;
id |= r;
}
return DNS_TRACE_ID_MASK & id;
}
struct dns_trace {
dns_atomic_t refcount;
FILE *fp;
dns_trace_id_t id;
struct {
struct dns_trace_cname {
char host[DNS_D_MAXNAME + 1];
struct sockaddr_storage addr;
} base[4];
size_t p;
} cnames;
};
static void dns_te_initname(struct sockaddr_storage *ss, int fd, int (* STDCALL f)(socket_fd_t, struct sockaddr *, socklen_t *)) {
socklen_t n = sizeof *ss;
if (0 != f(fd, (struct sockaddr *)ss, &n))
goto unspec;
if (n > sizeof *ss)
goto unspec;
return;
unspec:
memset(ss, '\0', sizeof *ss);
ss->ss_family = AF_UNSPEC;
}
static void dns_te_initnames(struct sockaddr_storage *local, struct sockaddr_storage *remote, int fd) {
dns_te_initname(local, fd, &getsockname);
dns_te_initname(remote, fd, &getpeername);
}
static struct dns_trace_event *dns_te_init(struct dns_trace_event *te, int type) {
/* NB: silence valgrind */
memset(te, '\0', offsetof(struct dns_trace_event, data));
te->type = type;
return te;
}
int dns_trace_abi(void) {
return DNS_TRACE_ABI;
}
struct dns_trace *dns_trace_open(FILE *fp, dns_error_t *error) {
static const struct dns_trace trace_initializer = { .refcount = 1 };
struct dns_trace *trace;
if (!(trace = malloc(sizeof *trace)))
goto syerr;
*trace = trace_initializer;
if (fp) {
trace->fp = fp;
} else if (!(fp = tmpfile())) {
goto syerr;
}
trace->id = dns_trace_mkid();
return trace;
syerr:
*error = dns_syerr();
dns_trace_close(trace);
return NULL;
} /* dns_trace_open() */
void dns_trace_close(struct dns_trace *trace) {
if (!trace || 1 != dns_trace_release(trace))
return;
if (trace->fp)
fclose(trace->fp);
free(trace);
} /* dns_trace_close() */
dns_refcount_t dns_trace_acquire(struct dns_trace *trace) {
return dns_atomic_fetch_add(&trace->refcount);
} /* dns_trace_acquire() */
static struct dns_trace *dns_trace_acquire_p(struct dns_trace *trace) {
return (trace)? dns_trace_acquire(trace), trace : NULL;
} /* dns_trace_acquire_p() */
dns_refcount_t dns_trace_release(struct dns_trace *trace) {
return dns_atomic_fetch_sub(&trace->refcount);
} /* dns_trace_release() */
dns_trace_id_t dns_trace_id(struct dns_trace *trace) {
return trace->id;
} /* dns_trace_id() */
dns_trace_id_t dns_trace_setid(struct dns_trace *trace, dns_trace_id_t id) {
trace->id = (id)? id : dns_trace_mkid();
return trace->id;
} /* dns_trace_setid() */
struct dns_trace_event *dns_trace_get(struct dns_trace *trace, struct dns_trace_event **tp, dns_error_t *error) {
return dns_trace_fget(tp, trace->fp, error);
} /* dns_trace_get() */
dns_error_t dns_trace_put(struct dns_trace *trace, const struct dns_trace_event *te, const void *data, size_t datasize) {
return dns_trace_fput(te, data, datasize, trace->fp);
} /* dns_trace_put() */
struct dns_trace_event *dns_trace_tag(struct dns_trace *trace, struct dns_trace_event *te) {
struct timeval tv;
te->id = trace->id;
gettimeofday(&tv, NULL);
dns_tv2ts(&te->ts, &tv);
te->abi = DNS_TRACE_ABI;
return te;
} /* dns_trace_tag() */
static dns_error_t dns_trace_tag_and_put(struct dns_trace *trace, struct dns_trace_event *te, const void *data, size_t datasize) {
return dns_trace_put(trace, dns_trace_tag(trace, te), data, datasize);
} /* dns_trace_tag_and_put() */
struct dns_trace_event *dns_trace_fget(struct dns_trace_event **tp, FILE *fp, dns_error_t *error) {
const size_t headsize = offsetof(struct dns_trace_event, data);
struct dns_trace_event tmp, *te;
size_t n;
errno = 0;
if (!(n = fread(&tmp, 1, headsize, fp)))
goto none;
if (n < offsetof(struct dns_trace_event, data))
goto some;
if (!(te = realloc(*tp, DNS_PP_MAX(headsize, tmp.size)))) {
*error = errno;
return NULL;
}
*tp = te;
memcpy(te, &tmp, offsetof(struct dns_trace_event, data));
if (dns_te_datasize(te)) {
errno = 0;
if (!(n = fread(te->data, 1, dns_te_datasize(te), fp)))
goto none;
if (n < dns_te_datasize(te))
goto some;
}
return te;
none:
*error = (ferror(fp))? errno : 0;
return NULL;
some:
*error = 0;
return NULL;
}
dns_error_t dns_trace_fput(const struct dns_trace_event *te, const void *data, size_t datasize, FILE *fp) {
size_t headsize = offsetof(struct dns_trace_event, data);
struct dns_trace_event tmp;
memcpy(&tmp, te, headsize);
tmp.size = headsize + datasize;
/* NB: ignore seek error as fp might not point to a regular file */
(void)fseek(fp, 0, SEEK_END);
if (fwrite(&tmp, 1, headsize, fp) < headsize)
return errno;
if (data)
if (fwrite(data, 1, datasize, fp) < datasize)
return errno;
if (fflush(fp))
return errno;
return 0;
}
static void dns_trace_setcname(struct dns_trace *trace, const char *host, const struct sockaddr *addr) {
struct dns_trace_cname *cname;
if (!trace || !trace->fp)
return;
cname = &trace->cnames.base[trace->cnames.p];
dns_strlcpy(cname->host, host, sizeof cname->host);
memcpy(&cname->addr, addr, DNS_PP_MIN(dns_sa_len(addr), sizeof cname->addr));
trace->cnames.p = (trace->cnames.p + 1) % lengthof(trace->cnames.base);
}
static const char *dns_trace_cname(struct dns_trace *trace, const struct sockaddr *addr) {
if (!trace || !trace->fp)
return NULL;
/* NB: start search from the write cursor to */
for (const struct dns_trace_cname *cname = trace->cnames.base; cname < endof(trace->cnames.base); cname++) {
if (0 == dns_sa_cmp((struct sockaddr *)addr, (struct sockaddr *)&cname->addr))
return cname->host;
}
return NULL;
}
static void dns_trace_res_submit(struct dns_trace *trace, const char *qname, enum dns_type qtype, enum dns_class qclass, int error) {
struct dns_trace_event te;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_RES_SUBMIT);
dns_strlcpy(te.res_submit.qname, qname, sizeof te.res_submit.qname);
te.res_submit.qtype = qtype;
te.res_submit.qclass = qclass;
te.res_submit.error = error;
dns_trace_tag_and_put(trace, &te, NULL, 0);
}
static void dns_trace_res_fetch(struct dns_trace *trace, const struct dns_packet *packet, int error) {
struct dns_trace_event te;
const void *data;
size_t datasize;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_RES_FETCH);
data = (packet)? packet->data : NULL;
datasize = (packet)? packet->end : 0;
te.res_fetch.error = error;
dns_trace_tag_and_put(trace, &te, data, datasize);
}
static void dns_trace_so_submit(struct dns_trace *trace, const struct dns_packet *packet, const struct sockaddr *haddr, int error) {
struct dns_trace_event te;
const char *cname;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SO_SUBMIT);
memcpy(&te.so_submit.haddr, haddr, DNS_PP_MIN(dns_sa_len(haddr), sizeof te.so_submit.haddr));
if ((cname = dns_trace_cname(trace, haddr)))
dns_strlcpy(te.so_submit.hname, cname, sizeof te.so_submit.hname);
te.so_submit.error = error;
dns_trace_tag_and_put(trace, &te, packet->data, packet->end);
}
static void dns_trace_so_verify(struct dns_trace *trace, const struct dns_packet *packet, int error) {
struct dns_trace_event te;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SO_VERIFY);
te.so_verify.error = error;
dns_trace_tag_and_put(trace, &te, packet->data, packet->end);
}
static void dns_trace_so_fetch(struct dns_trace *trace, const struct dns_packet *packet, int error) {
struct dns_trace_event te;
const void *data;
size_t datasize;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SO_FETCH);
data = (packet)? packet->data : NULL;
datasize = (packet)? packet->end : 0;
te.so_fetch.error = error;
dns_trace_tag_and_put(trace, &te, data, datasize);
}
static void dns_trace_sys_connect(struct dns_trace *trace, int fd, int socktype, const struct sockaddr *dst, int error) {
struct dns_trace_event te;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SYS_CONNECT);
dns_te_initname(&te.sys_connect.src, fd, &getsockname);
memcpy(&te.sys_connect.dst, dst, DNS_PP_MIN(dns_sa_len(dst), sizeof te.sys_connect.dst));
te.sys_connect.socktype = socktype;
te.sys_connect.error = error;
dns_trace_tag_and_put(trace, &te, NULL, 0);
}
static void dns_trace_sys_send(struct dns_trace *trace, int fd, int socktype, const void *data, size_t datasize, int error) {
struct dns_trace_event te;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SYS_SEND);
dns_te_initnames(&te.sys_send.src, &te.sys_send.dst, fd);
te.sys_send.socktype = socktype;
te.sys_send.error = error;
dns_trace_tag_and_put(trace, &te, data, datasize);
}
static void dns_trace_sys_recv(struct dns_trace *trace, int fd, int socktype, const void *data, size_t datasize, int error) {
struct dns_trace_event te;
if (!trace || !trace->fp)
return;
dns_te_init(&te, DNS_TE_SYS_RECV);
dns_te_initnames(&te.sys_recv.dst, &te.sys_recv.src, fd);
te.sys_recv.socktype = socktype;
te.sys_recv.error = error;
dns_trace_tag_and_put(trace, &te, data, datasize);
}
static dns_error_t dns_trace_dump_packet(struct dns_trace *trace, const char *prefix, const unsigned char *data, size_t datasize, FILE *fp) {
struct dns_packet *packet = NULL;
char *line = NULL, *p;
size_t size = 1, skip = 0;
struct dns_rr_i records;
struct dns_p_lines_i lines;
size_t len, count;
int error;
if (!(packet = dns_p_make(datasize, &error)))
goto error;
memcpy(packet->data, data, datasize);
packet->end = datasize;
(void)dns_p_study(packet);
resize:
if (!(p = dns_reallocarray(line, size, 2, &error)))
goto error;
line = p;
size *= 2;
memset(&records, 0, sizeof records);
memset(&lines, 0, sizeof lines);
count = 0;
while ((len = dns_p_lines(line, size, &error, packet, &records, &lines))) {
if (!(len < size)) {
skip = count;
goto resize;
} else if (skip <= count) {
fputs(prefix, fp);
fwrite(line, 1, len, fp);
}
count++;
}
if (error)
goto error;
error = 0;
error:
free(line);
dns_p_free(packet);
return error;
}
static dns_error_t dns_trace_dump_data(struct dns_trace *trace, const char *prefix, const unsigned char *data, size_t datasize, FILE *fp) {
struct dns_hxd_lines_i lines = { 0 };
char line[128];
size_t len;
while ((len = dns_hxd_lines(line, sizeof line, data, datasize, &lines))) {
if (len >= sizeof line)
return EOVERFLOW; /* shouldn't be possible */
fputs(prefix, fp);
fwrite(line, 1, len, fp);
}
return 0;
}
static dns_error_t dns_trace_dump_addr(struct dns_trace *trace, const char *prefix, const struct sockaddr_storage *ss, FILE *fp) {
const void *addr;
const char *path;
socklen_t len;
int error;
if ((addr = dns_sa_addr(ss->ss_family, (struct sockaddr *)ss, NULL))) {
char ip[INET6_ADDRSTRLEN + 1];
if ((error = dns_ntop(ss->ss_family, addr, ip, sizeof ip)))
return error;
fprintf(fp, "%s%s\n", prefix, ip);
} else if ((path = dns_sa_path((struct sockaddr *)ss, &len))) {
fprintf(fp, "%sunix:%.*s", prefix, (int)len, path);
} else {
return EINVAL;
}
return 0;
}
static dns_error_t dns_trace_dump_meta(struct dns_trace *trace, const char *prefix, const struct dns_trace_event *te, dns_microseconds_t elapsed, FILE *fp) {
char time_s[48], elapsed_s[48];
dns_utime_print(time_s, sizeof time_s, dns_ts2us(&te->ts, 0));
dns_utime_print(elapsed_s, sizeof elapsed_s, elapsed);
fprintf(fp, "%sid: %"DNS_TRACE_ID_PRI"\n", prefix, te->id);
fprintf(fp, "%sts: %s (%s)\n", prefix, time_s, elapsed_s);
fprintf(fp, "%sabi: 0x%x (0x%x)\n", prefix, te->abi, DNS_TRACE_ABI);
return 0;
}
static dns_error_t dns_trace_dump_error(struct dns_trace *trace, const char *prefix, int error, FILE *fp) {
fprintf(fp, "%s%d (%s)\n", prefix, error, (error)? dns_strerror(error) : "none");
return 0;
}
dns_error_t dns_trace_dump(struct dns_trace *trace, FILE *fp) {
struct dns_trace_event *te = NULL;
struct {
dns_trace_id_t id;
dns_microseconds_t begin, elapsed;
} state = { 0 };
int error;
if (!trace || !trace->fp)
return EINVAL;
if (0 != fseek(trace->fp, 0, SEEK_SET))
goto syerr;
while (dns_trace_fget(&te, trace->fp, &error)) {
size_t datasize = dns_te_datasize(te);
const unsigned char *data = (datasize)? te->data : NULL;
if (state.id != te->id) {
state.id = te->id;
state.begin = dns_ts2us(&te->ts, 0);
}
dns_time_diff(&state.elapsed, dns_ts2us(&te->ts, 0), state.begin);
switch(te->type) {
case DNS_TE_RES_SUBMIT:
fprintf(fp, "dns_res_submit:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
fprintf(fp, " qname: %s\n", te->res_submit.qname);
fprintf(fp, " qtype: %s\n", dns_strtype(te->res_submit.qtype));
fprintf(fp, " qclass: %s\n", dns_strclass(te->res_submit.qclass));
dns_trace_dump_error(trace, " error: ", te->res_submit.error, fp);
break;
case DNS_TE_RES_FETCH:
fprintf(fp, "dns_res_fetch:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_error(trace, " error: ", te->res_fetch.error, fp);
if (data) {
fprintf(fp, " packet: |\n");
if ((error = dns_trace_dump_packet(trace, " ", data, datasize, fp)))
goto error;
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
case DNS_TE_SO_SUBMIT:
fprintf(fp, "dns_so_submit:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
fprintf(fp, " hname: %s\n", te->so_submit.hname);
dns_trace_dump_addr(trace, " haddr: ", &te->so_submit.haddr, fp);
dns_trace_dump_error(trace, " error: ", te->so_submit.error, fp);
if (data) {
fprintf(fp, " packet: |\n");
if ((error = dns_trace_dump_packet(trace, " ", data, datasize, fp)))
goto error;
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
case DNS_TE_SO_VERIFY:
fprintf(fp, "dns_so_verify:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_error(trace, " error: ", te->so_verify.error, fp);
if (data) {
fprintf(fp, " packet: |\n");
if ((error = dns_trace_dump_packet(trace, " ", data, datasize, fp)))
goto error;
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
case DNS_TE_SO_FETCH:
fprintf(fp, "dns_so_fetch:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_error(trace, " error: ", te->so_fetch.error, fp);
if (data) {
fprintf(fp, " packet: |\n");
if ((error = dns_trace_dump_packet(trace, " ", data, datasize, fp)))
goto error;
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
case DNS_TE_SYS_CONNECT: {
int socktype = te->sys_connect.socktype;
fprintf(fp, "dns_sys_connect:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_addr(trace, " src: ", &te->sys_connect.src, fp);
dns_trace_dump_addr(trace, " dst: ", &te->sys_connect.dst, fp);
fprintf(fp, " socktype: %d (%s)\n", socktype, ((socktype == SOCK_STREAM)? "SOCK_STREAM" : (socktype == SOCK_DGRAM)? "SOCK_DGRAM" : "?"));
dns_trace_dump_error(trace, " error: ", te->sys_connect.error, fp);
break;
}
case DNS_TE_SYS_SEND: {
int socktype = te->sys_send.socktype;
fprintf(fp, "dns_sys_send:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_addr(trace, " src: ", &te->sys_send.src, fp);
dns_trace_dump_addr(trace, " dst: ", &te->sys_send.dst, fp);
fprintf(fp, " socktype: %d (%s)\n", socktype, ((socktype == SOCK_STREAM)? "SOCK_STREAM" : (socktype == SOCK_DGRAM)? "SOCK_DGRAM" : "?"));
dns_trace_dump_error(trace, " error: ", te->sys_send.error, fp);
if (data) {
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
}
case DNS_TE_SYS_RECV: {
int socktype = te->sys_recv.socktype;
fprintf(fp, "dns_sys_recv:\n");
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
dns_trace_dump_addr(trace, " src: ", &te->sys_recv.src, fp);
dns_trace_dump_addr(trace, " dst: ", &te->sys_recv.dst, fp);
fprintf(fp, " socktype: %d (%s)\n", socktype, ((socktype == SOCK_STREAM)? "SOCK_STREAM" : (socktype == SOCK_DGRAM)? "SOCK_DGRAM" : "?"));
dns_trace_dump_error(trace, " error: ", te->sys_recv.error, fp);
if (data) {
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
}
default:
fprintf(fp, "unknown(0x%.2x):\n", te->type);
dns_trace_dump_meta(trace, " ", te, state.elapsed, fp);
if (data) {
fprintf(fp, " data: |\n");
if ((error = dns_trace_dump_data(trace, " ", data, datasize, fp)))
goto error;
}
break;
}
}
goto epilog;
syerr:
error = errno;
error:
(void)0;
epilog:
free(te);
return error;
}
/*
* H O S T S R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct dns_hosts {
struct dns_hosts_entry {
char host[DNS_D_MAXNAME + 1];
char arpa[73 + 1];
int af;
union {
struct in_addr a4;
struct in6_addr a6;
} addr;
_Bool alias;
struct dns_hosts_entry *next;
} *head, **tail;
dns_atomic_t refcount;
}; /* struct dns_hosts */
struct dns_hosts *dns_hosts_open(int *error) {
static const struct dns_hosts hosts_initializer = { .refcount = 1 };
struct dns_hosts *hosts;
if (!(hosts = malloc(sizeof *hosts)))
goto syerr;
*hosts = hosts_initializer;
hosts->tail = &hosts->head;
return hosts;
syerr:
*error = dns_syerr();
free(hosts);
return 0;
} /* dns_hosts_open() */
void dns_hosts_close(struct dns_hosts *hosts) {
struct dns_hosts_entry *ent, *xnt;
if (!hosts || 1 != dns_hosts_release(hosts))
return;
for (ent = hosts->head; ent; ent = xnt) {
xnt = ent->next;
free(ent);
}
free(hosts);
return;
} /* dns_hosts_close() */
dns_refcount_t dns_hosts_acquire(struct dns_hosts *hosts) {
return dns_atomic_fetch_add(&hosts->refcount);
} /* dns_hosts_acquire() */
dns_refcount_t dns_hosts_release(struct dns_hosts *hosts) {
return dns_atomic_fetch_sub(&hosts->refcount);
} /* dns_hosts_release() */
struct dns_hosts *dns_hosts_mortal(struct dns_hosts *hosts) {
if (hosts)
dns_hosts_release(hosts);
return hosts;
} /* dns_hosts_mortal() */
struct dns_hosts *dns_hosts_local(int *error_) {
struct dns_hosts *hosts;
int error;
if (!(hosts = dns_hosts_open(&error)))
goto error;
if ((error = dns_hosts_loadpath(hosts, "/etc/hosts")))
goto error;
return hosts;
error:
*error_ = error;
dns_hosts_close(hosts);
return 0;
} /* dns_hosts_local() */
#define dns_hosts_issep(ch) (dns_isspace(ch))
#define dns_hosts_iscom(ch) ((ch) == '#' || (ch) == ';')
int dns_hosts_loadfile(struct dns_hosts *hosts, FILE *fp) {
struct dns_hosts_entry ent;
char word[DNS_PP_MAX(INET6_ADDRSTRLEN, DNS_D_MAXNAME) + 1];
unsigned wp, wc, skip;
int ch, error;
rewind(fp);
do {
memset(&ent, '\0', sizeof ent);
wc = 0;
skip = 0;
do {
memset(word, '\0', sizeof word);
wp = 0;
while (EOF != (ch = fgetc(fp)) && ch != '\n') {
skip |= !!dns_hosts_iscom(ch);
if (skip)
continue;
if (dns_hosts_issep(ch))
break;
if (wp < sizeof word - 1)
word[wp] = ch;
wp++;
}
if (!wp)
continue;
wc++;
switch (wc) {
case 0:
break;
case 1:
ent.af = (strchr(word, ':'))? AF_INET6 : AF_INET;
skip = (1 != dns_inet_pton(ent.af, word, &ent.addr));
break;
default:
if (!wp)
break;
dns_d_anchor(ent.host, sizeof ent.host, word, wp);
if ((error = dns_hosts_insert(hosts, ent.af, &ent.addr, ent.host, (wc > 2))))
return error;
break;
} /* switch() */
} while (ch != EOF && ch != '\n');
} while (ch != EOF);
return 0;
} /* dns_hosts_loadfile() */
int dns_hosts_loadpath(struct dns_hosts *hosts, const char *path) {
FILE *fp;
int error;
if (!(fp = dns_fopen(path, "rt", &error)))
return error;
error = dns_hosts_loadfile(hosts, fp);
fclose(fp);
return error;
} /* dns_hosts_loadpath() */
int dns_hosts_dump(struct dns_hosts *hosts, FILE *fp) {
struct dns_hosts_entry *ent, *xnt;
char addr[INET6_ADDRSTRLEN + 1];
unsigned i;
for (ent = hosts->head; ent; ent = xnt) {
xnt = ent->next;
dns_inet_ntop(ent->af, &ent->addr, addr, sizeof addr);
fputs(addr, fp);
for (i = strlen(addr); i < INET_ADDRSTRLEN; i++)
fputc(' ', fp);
fputc(' ', fp);
fputs(ent->host, fp);
fputc('\n', fp);
}
return 0;
} /* dns_hosts_dump() */
int dns_hosts_insert(struct dns_hosts *hosts, int af, const void *addr, const void *host, _Bool alias) {
struct dns_hosts_entry *ent;
int error;
if (!(ent = malloc(sizeof *ent)))
goto syerr;
dns_d_anchor(ent->host, sizeof ent->host, host, strlen(host));
switch ((ent->af = af)) {
case AF_INET6:
memcpy(&ent->addr.a6, addr, sizeof ent->addr.a6);
dns_aaaa_arpa(ent->arpa, sizeof ent->arpa, addr);
break;
case AF_INET:
memcpy(&ent->addr.a4, addr, sizeof ent->addr.a4);
dns_a_arpa(ent->arpa, sizeof ent->arpa, addr);
break;
default:
error = EINVAL;
goto error;
} /* switch() */
ent->alias = alias;
ent->next = 0;
*hosts->tail = ent;
hosts->tail = &ent->next;
return 0;
syerr:
error = dns_syerr();
error:
free(ent);
return error;
} /* dns_hosts_insert() */
struct dns_packet *dns_hosts_query(struct dns_hosts *hosts, struct dns_packet *Q, int *error_) {
struct dns_packet *P = dns_p_new(512);
struct dns_packet *A = 0;
struct dns_rr rr;
struct dns_hosts_entry *ent;
int error, af;
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
if ((error = dns_rr_parse(&rr, 12, Q)))
goto error;
if (!(qlen = dns_d_expand(qname, sizeof qname, rr.dn.p, Q, &error)))
goto error;
else if (qlen >= sizeof qname)
goto toolong;
if ((error = dns_p_push(P, DNS_S_QD, qname, qlen, rr.type, rr.class, 0, 0)))
goto error;
switch (rr.type) {
case DNS_T_PTR:
for (ent = hosts->head; ent; ent = ent->next) {
if (ent->alias || 0 != strcasecmp(qname, ent->arpa))
continue;
if ((error = dns_p_push(P, DNS_S_AN, qname, qlen, rr.type, rr.class, 0, ent->host)))
goto error;
}
break;
case DNS_T_AAAA:
af = AF_INET6;
goto loop;
case DNS_T_A:
af = AF_INET;
loop: for (ent = hosts->head; ent; ent = ent->next) {
if (ent->af != af || 0 != strcasecmp(qname, ent->host))
continue;
if ((error = dns_p_push(P, DNS_S_AN, qname, qlen, rr.type, rr.class, 0, &ent->addr)))
goto error;
}
break;
default:
break;
} /* switch() */
if (!(A = dns_p_copy(dns_p_make(P->end, &error), P)))
goto error;
return A;
toolong:
error = DNS_EILLEGAL;
error:
*error_ = error;
dns_p_free(A);
return 0;
} /* dns_hosts_query() */
/*
* R E S O L V . C O N F R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct dns_resolv_conf *dns_resconf_open(int *error) {
static const struct dns_resolv_conf resconf_initializer = {
.lookup = "bf",
.family = { AF_INET, AF_INET6 },
.options = { .ndots = 1, .timeout = 5, .attempts = 2, .tcp = DNS_RESCONF_TCP_ENABLE, },
.iface = { .ss_family = AF_INET },
};
struct dns_resolv_conf *resconf;
struct sockaddr_in *sin;
if (!(resconf = malloc(sizeof *resconf)))
goto syerr;
*resconf = resconf_initializer;
sin = (struct sockaddr_in *)&resconf->nameserver[0];
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = INADDR_ANY;
sin->sin_port = htons(53);
#if defined(SA_LEN)
sin->sin_len = sizeof *sin;
#endif
if (0 != gethostname(resconf->search[0], sizeof resconf->search[0]))
goto syerr;
/*
* If gethostname() returned a string without any label
* separator, then search[0][0] should be NUL.
*/
if (strchr (resconf->search[0], '.')) {
dns_d_anchor(resconf->search[0], sizeof resconf->search[0], resconf->search[0], strlen(resconf->search[0]));
dns_d_cleave(resconf->search[0], sizeof resconf->search[0], resconf->search[0], strlen(resconf->search[0]));
} else {
memset (resconf->search[0], 0, sizeof resconf->search[0]);
}
dns_resconf_acquire(resconf);
return resconf;
syerr:
*error = dns_syerr();
free(resconf);
return 0;
} /* dns_resconf_open() */
void dns_resconf_close(struct dns_resolv_conf *resconf) {
if (!resconf || 1 != dns_resconf_release(resconf))
return /* void */;
free(resconf);
} /* dns_resconf_close() */
dns_refcount_t dns_resconf_acquire(struct dns_resolv_conf *resconf) {
return dns_atomic_fetch_add(&resconf->_.refcount);
} /* dns_resconf_acquire() */
dns_refcount_t dns_resconf_release(struct dns_resolv_conf *resconf) {
return dns_atomic_fetch_sub(&resconf->_.refcount);
} /* dns_resconf_release() */
struct dns_resolv_conf *dns_resconf_mortal(struct dns_resolv_conf *resconf) {
if (resconf)
dns_resconf_release(resconf);
return resconf;
} /* dns_resconf_mortal() */
struct dns_resolv_conf *dns_resconf_local(int *error_) {
struct dns_resolv_conf *resconf;
int error;
if (!(resconf = dns_resconf_open(&error)))
goto error;
if ((error = dns_resconf_loadpath(resconf, "/etc/resolv.conf"))) {
/*
* NOTE: Both the glibc and BIND9 resolvers ignore a missing
* /etc/resolv.conf, defaulting to a nameserver of
* 127.0.0.1. See also dns_hints_insert_resconf, and the
* default initialization of nameserver[0] in
* dns_resconf_open.
*/
if (error != ENOENT)
goto error;
}
if ((error = dns_nssconf_loadpath(resconf, "/etc/nsswitch.conf"))) {
if (error != ENOENT)
goto error;
}
return resconf;
error:
*error_ = error;
dns_resconf_close(resconf);
return 0;
} /* dns_resconf_local() */
struct dns_resolv_conf *dns_resconf_root(int *error) {
struct dns_resolv_conf *resconf;
if ((resconf = dns_resconf_local(error)))
resconf->options.recurse = 1;
return resconf;
} /* dns_resconf_root() */
static time_t dns_resconf_timeout(const struct dns_resolv_conf *resconf) {
return (time_t)DNS_PP_MIN(INT_MAX, resconf->options.timeout);
} /* dns_resconf_timeout() */
enum dns_resconf_keyword {
DNS_RESCONF_NAMESERVER,
DNS_RESCONF_DOMAIN,
DNS_RESCONF_SEARCH,
DNS_RESCONF_LOOKUP,
DNS_RESCONF_FILE,
DNS_RESCONF_BIND,
DNS_RESCONF_CACHE,
DNS_RESCONF_FAMILY,
DNS_RESCONF_INET4,
DNS_RESCONF_INET6,
DNS_RESCONF_OPTIONS,
DNS_RESCONF_EDNS0,
DNS_RESCONF_NDOTS,
DNS_RESCONF_TIMEOUT,
DNS_RESCONF_ATTEMPTS,
DNS_RESCONF_ROTATE,
DNS_RESCONF_RECURSE,
DNS_RESCONF_SMART,
DNS_RESCONF_TCP,
DNS_RESCONF_TCPx,
DNS_RESCONF_INTERFACE,
DNS_RESCONF_ZERO,
DNS_RESCONF_ONE,
DNS_RESCONF_ENABLE,
DNS_RESCONF_ONLY,
DNS_RESCONF_DISABLE,
}; /* enum dns_resconf_keyword */
static enum dns_resconf_keyword dns_resconf_keyword(const char *word) {
static const char *words[] = {
[DNS_RESCONF_NAMESERVER] = "nameserver",
[DNS_RESCONF_DOMAIN] = "domain",
[DNS_RESCONF_SEARCH] = "search",
[DNS_RESCONF_LOOKUP] = "lookup",
[DNS_RESCONF_FILE] = "file",
[DNS_RESCONF_BIND] = "bind",
[DNS_RESCONF_CACHE] = "cache",
[DNS_RESCONF_FAMILY] = "family",
[DNS_RESCONF_INET4] = "inet4",
[DNS_RESCONF_INET6] = "inet6",
[DNS_RESCONF_OPTIONS] = "options",
[DNS_RESCONF_EDNS0] = "edns0",
[DNS_RESCONF_ROTATE] = "rotate",
[DNS_RESCONF_RECURSE] = "recurse",
[DNS_RESCONF_SMART] = "smart",
[DNS_RESCONF_TCP] = "tcp",
[DNS_RESCONF_INTERFACE] = "interface",
[DNS_RESCONF_ZERO] = "0",
[DNS_RESCONF_ONE] = "1",
[DNS_RESCONF_ENABLE] = "enable",
[DNS_RESCONF_ONLY] = "only",
[DNS_RESCONF_DISABLE] = "disable",
};
unsigned i;
for (i = 0; i < lengthof(words); i++) {
if (words[i] && 0 == strcasecmp(words[i], word))
return i;
}
if (0 == strncasecmp(word, "ndots:", sizeof "ndots:" - 1))
return DNS_RESCONF_NDOTS;
if (0 == strncasecmp(word, "timeout:", sizeof "timeout:" - 1))
return DNS_RESCONF_TIMEOUT;
if (0 == strncasecmp(word, "attempts:", sizeof "attempts:" - 1))
return DNS_RESCONF_ATTEMPTS;
if (0 == strncasecmp(word, "tcp:", sizeof "tcp:" - 1))
return DNS_RESCONF_TCPx;
return -1;
} /* dns_resconf_keyword() */
/** OpenBSD-style "[1.2.3.4]:53" nameserver syntax */
int dns_resconf_pton(struct sockaddr_storage *ss, const char *src) {
struct { char buf[128], *p; } addr = { "", addr.buf };
unsigned short port = 0;
int ch, af = AF_INET, error;
memset(ss, 0, sizeof *ss);
while ((ch = *src++)) {
switch (ch) {
case ' ':
/* FALL THROUGH */
case '\t':
break;
case '[':
break;
case ']':
while ((ch = *src++)) {
if (dns_isdigit(ch)) {
port *= 10;
port += ch - '0';
}
}
goto inet;
case ':':
af = AF_INET6;
/* FALL THROUGH */
default:
if (addr.p < endof(addr.buf) - 1)
*addr.p++ = ch;
break;
} /* switch() */
} /* while() */
inet:
if ((error = dns_pton(af, addr.buf, dns_sa_addr(af, ss, NULL))))
return error;
port = (!port)? 53 : port;
*dns_sa_port(af, ss) = htons(port);
dns_sa_family(ss) = af;
return 0;
} /* dns_resconf_pton() */
#define dns_resconf_issep(ch) (dns_isspace(ch) || (ch) == ',')
#define dns_resconf_iscom(ch) ((ch) == '#' || (ch) == ';')
int dns_resconf_loadfile(struct dns_resolv_conf *resconf, FILE *fp) {
unsigned sa_count = 0;
char words[6][DNS_D_MAXNAME + 1];
unsigned wp, wc, i, j, n;
int ch, error;
rewind(fp);
do {
memset(words, '\0', sizeof words);
wp = 0;
wc = 0;
while (EOF != (ch = getc(fp)) && ch != '\n') {
if (dns_resconf_issep(ch)) {
if (wp > 0) {
wp = 0;
if (++wc >= lengthof(words))
goto skip;
}
} else if (dns_resconf_iscom(ch)) {
skip:
do {
ch = getc(fp);
} while (ch != EOF && ch != '\n');
break;
} else if (wp < sizeof words[wc] - 1) {
words[wc][wp++] = ch;
} else {
wp = 0; /* drop word */
goto skip;
}
}
if (wp > 0)
wc++;
if (wc < 2)
continue;
switch (dns_resconf_keyword(words[0])) {
case DNS_RESCONF_NAMESERVER:
if (sa_count >= lengthof(resconf->nameserver))
continue;
if ((error = dns_resconf_pton(&resconf->nameserver[sa_count], words[1])))
continue;
sa_count++;
break;
case DNS_RESCONF_DOMAIN:
case DNS_RESCONF_SEARCH:
memset(resconf->search, '\0', sizeof resconf->search);
for (i = 1, j = 0; i < wc && j < lengthof(resconf->search); i++, j++)
dns_d_anchor(resconf->search[j], sizeof resconf->search[j], words[i], strlen(words[i]));
break;
case DNS_RESCONF_LOOKUP:
for (i = 1, j = 0; i < wc && j < lengthof(resconf->lookup); i++) {
switch (dns_resconf_keyword(words[i])) {
case DNS_RESCONF_FILE:
resconf->lookup[j++] = 'f';
break;
case DNS_RESCONF_BIND:
resconf->lookup[j++] = 'b';
break;
case DNS_RESCONF_CACHE:
resconf->lookup[j++] = 'c';
break;
default:
break;
} /* switch() */
} /* for() */
break;
case DNS_RESCONF_FAMILY:
for (i = 1, j = 0; i < wc && j < lengthof(resconf->family); i++) {
switch (dns_resconf_keyword(words[i])) {
case DNS_RESCONF_INET4:
resconf->family[j++] = AF_INET;
break;
case DNS_RESCONF_INET6:
resconf->family[j++] = AF_INET6;
break;
default:
break;
}
}
break;
case DNS_RESCONF_OPTIONS:
for (i = 1; i < wc; i++) {
switch (dns_resconf_keyword(words[i])) {
case DNS_RESCONF_EDNS0:
resconf->options.edns0 = 1;
break;
case DNS_RESCONF_NDOTS:
for (j = sizeof "ndots:" - 1, n = 0; dns_isdigit(words[i][j]); j++) {
n *= 10;
n += words[i][j] - '0';
} /* for() */
resconf->options.ndots = n;
break;
case DNS_RESCONF_TIMEOUT:
for (j = sizeof "timeout:" - 1, n = 0; dns_isdigit(words[i][j]); j++) {
n *= 10;
n += words[i][j] - '0';
} /* for() */
resconf->options.timeout = n;
break;
case DNS_RESCONF_ATTEMPTS:
for (j = sizeof "attempts:" - 1, n = 0; dns_isdigit(words[i][j]); j++) {
n *= 10;
n += words[i][j] - '0';
} /* for() */
resconf->options.attempts = n;
break;
case DNS_RESCONF_ROTATE:
resconf->options.rotate = 1;
break;
case DNS_RESCONF_RECURSE:
resconf->options.recurse = 1;
break;
case DNS_RESCONF_SMART:
resconf->options.smart = 1;
break;
case DNS_RESCONF_TCP:
resconf->options.tcp = DNS_RESCONF_TCP_ONLY;
break;
case DNS_RESCONF_TCPx:
switch (dns_resconf_keyword(&words[i][sizeof "tcp:" - 1])) {
case DNS_RESCONF_ENABLE:
resconf->options.tcp = DNS_RESCONF_TCP_ENABLE;
break;
case DNS_RESCONF_ONE:
case DNS_RESCONF_ONLY:
resconf->options.tcp = DNS_RESCONF_TCP_ONLY;
break;
case DNS_RESCONF_ZERO:
case DNS_RESCONF_DISABLE:
resconf->options.tcp = DNS_RESCONF_TCP_DISABLE;
break;
default:
break;
} /* switch() */
break;
default:
break;
} /* switch() */
} /* for() */
break;
case DNS_RESCONF_INTERFACE:
for (i = 0, n = 0; dns_isdigit(words[2][i]); i++) {
n *= 10;
n += words[2][i] - '0';
}
dns_resconf_setiface(resconf, words[1], n);
break;
default:
break;
} /* switch() */
} while (ch != EOF);
return 0;
} /* dns_resconf_loadfile() */
int dns_resconf_loadpath(struct dns_resolv_conf *resconf, const char *path) {
FILE *fp;
int error;
if (!(fp = dns_fopen(path, "rt", &error)))
return error;
error = dns_resconf_loadfile(resconf, fp);
fclose(fp);
return error;
} /* dns_resconf_loadpath() */
struct dns_anyconf {
char *token[16];
unsigned count;
char buffer[1024], *tp, *cp;
}; /* struct dns_anyconf */
static void dns_anyconf_reset(struct dns_anyconf *cf) {
cf->count = 0;
cf->tp = cf->cp = cf->buffer;
} /* dns_anyconf_reset() */
static int dns_anyconf_push(struct dns_anyconf *cf) {
if (!(cf->cp < endof(cf->buffer) && cf->count < lengthof(cf->token)))
return ENOMEM;
*cf->cp++ = '\0';
cf->token[cf->count++] = cf->tp;
cf->tp = cf->cp;
return 0;
} /* dns_anyconf_push() */
static void dns_anyconf_pop(struct dns_anyconf *cf) {
if (cf->count > 0) {
--cf->count;
cf->tp = cf->cp = cf->token[cf->count];
cf->token[cf->count] = 0;
}
} /* dns_anyconf_pop() */
static int dns_anyconf_addc(struct dns_anyconf *cf, int ch) {
if (!(cf->cp < endof(cf->buffer)))
return ENOMEM;
*cf->cp++ = ch;
return 0;
} /* dns_anyconf_addc() */
static _Bool dns_anyconf_match(const char *pat, int mc) {
_Bool match;
int pc;
if (*pat == '^') {
match = 0;
++pat;
} else {
match = 1;
}
while ((pc = *(const unsigned char *)pat++)) {
switch (pc) {
case '%':
if (!(pc = *(const unsigned char *)pat++))
return !match;
switch (pc) {
case 'a':
if (dns_isalpha(mc))
return match;
break;
case 'd':
if (dns_isdigit(mc))
return match;
break;
case 'w':
if (dns_isalnum(mc))
return match;
break;
case 's':
if (dns_isspace(mc))
return match;
break;
default:
if (mc == pc)
return match;
break;
} /* switch() */
break;
default:
if (mc == pc)
return match;
break;
} /* switch() */
} /* while() */
return !match;
} /* dns_anyconf_match() */
static int dns_anyconf_peek(FILE *fp) {
int ch;
ch = getc(fp);
ungetc(ch, fp);
return ch;
} /* dns_anyconf_peek() */
static size_t dns_anyconf_skip(const char *pat, FILE *fp) {
size_t count = 0;
int ch;
while (EOF != (ch = getc(fp))) {
if (dns_anyconf_match(pat, ch)) {
count++;
continue;
}
ungetc(ch, fp);
break;
}
return count;
} /* dns_anyconf_skip() */
static size_t dns_anyconf_scan(struct dns_anyconf *cf, const char *pat, FILE *fp, int *error) {
size_t len;
int ch;
while (EOF != (ch = getc(fp))) {
if (dns_anyconf_match(pat, ch)) {
if ((*error = dns_anyconf_addc(cf, ch)))
return 0;
continue;
} else {
ungetc(ch, fp);
break;
}
}
if ((len = cf->cp - cf->tp)) {
if ((*error = dns_anyconf_push(cf)))
return 0;
return len;
} else {
*error = 0;
return 0;
}
} /* dns_anyconf_scan() */
DNS_NOTUSED static void dns_anyconf_dump(struct dns_anyconf *cf, FILE *fp) {
unsigned i;
fprintf(fp, "tokens:");
for (i = 0; i < cf->count; i++) {
fprintf(fp, " %s", cf->token[i]);
}
fputc('\n', fp);
} /* dns_anyconf_dump() */
enum dns_nssconf_keyword {
DNS_NSSCONF_INVALID = 0,
DNS_NSSCONF_HOSTS = 1,
DNS_NSSCONF_SUCCESS,
DNS_NSSCONF_NOTFOUND,
DNS_NSSCONF_UNAVAIL,
DNS_NSSCONF_TRYAGAIN,
DNS_NSSCONF_CONTINUE,
DNS_NSSCONF_RETURN,
DNS_NSSCONF_FILES,
DNS_NSSCONF_DNS,
DNS_NSSCONF_MDNS,
DNS_NSSCONF_LAST,
}; /* enum dns_nssconf_keyword */
static enum dns_nssconf_keyword dns_nssconf_keyword(const char *word) {
static const char *list[] = {
[DNS_NSSCONF_HOSTS] = "hosts",
[DNS_NSSCONF_SUCCESS] = "success",
[DNS_NSSCONF_NOTFOUND] = "notfound",
[DNS_NSSCONF_UNAVAIL] = "unavail",
[DNS_NSSCONF_TRYAGAIN] = "tryagain",
[DNS_NSSCONF_CONTINUE] = "continue",
[DNS_NSSCONF_RETURN] = "return",
[DNS_NSSCONF_FILES] = "files",
[DNS_NSSCONF_DNS] = "dns",
[DNS_NSSCONF_MDNS] = "mdns",
};
unsigned i;
for (i = 1; i < lengthof(list); i++) {
if (list[i] && 0 == strcasecmp(list[i], word))
return i;
}
return DNS_NSSCONF_INVALID;
} /* dns_nssconf_keyword() */
static enum dns_nssconf_keyword dns_nssconf_c2k(int ch) {
static const char map[] = {
['S'] = DNS_NSSCONF_SUCCESS,
['N'] = DNS_NSSCONF_NOTFOUND,
['U'] = DNS_NSSCONF_UNAVAIL,
['T'] = DNS_NSSCONF_TRYAGAIN,
['C'] = DNS_NSSCONF_CONTINUE,
['R'] = DNS_NSSCONF_RETURN,
['f'] = DNS_NSSCONF_FILES,
['F'] = DNS_NSSCONF_FILES,
['d'] = DNS_NSSCONF_DNS,
['D'] = DNS_NSSCONF_DNS,
['b'] = DNS_NSSCONF_DNS,
['B'] = DNS_NSSCONF_DNS,
['m'] = DNS_NSSCONF_MDNS,
['M'] = DNS_NSSCONF_MDNS,
};
return (ch >= 0 && ch < (int)lengthof(map))? map[ch] : DNS_NSSCONF_INVALID;
} /* dns_nssconf_c2k() */
DNS_PRAGMA_PUSH
DNS_PRAGMA_QUIET
static int dns_nssconf_k2c(int k) {
static const char map[DNS_NSSCONF_LAST] = {
[DNS_NSSCONF_SUCCESS] = 'S',
[DNS_NSSCONF_NOTFOUND] = 'N',
[DNS_NSSCONF_UNAVAIL] = 'U',
[DNS_NSSCONF_TRYAGAIN] = 'T',
[DNS_NSSCONF_CONTINUE] = 'C',
[DNS_NSSCONF_RETURN] = 'R',
[DNS_NSSCONF_FILES] = 'f',
[DNS_NSSCONF_DNS] = 'b',
[DNS_NSSCONF_MDNS] = 'm',
};
return (k >= 0 && k < (int)lengthof(map))? (map[k]? map[k] : '?') : '?';
} /* dns_nssconf_k2c() */
static const char *dns_nssconf_k2s(int k) {
static const char *const map[DNS_NSSCONF_LAST] = {
[DNS_NSSCONF_SUCCESS] = "SUCCESS",
[DNS_NSSCONF_NOTFOUND] = "NOTFOUND",
[DNS_NSSCONF_UNAVAIL] = "UNAVAIL",
[DNS_NSSCONF_TRYAGAIN] = "TRYAGAIN",
[DNS_NSSCONF_CONTINUE] = "continue",
[DNS_NSSCONF_RETURN] = "return",
[DNS_NSSCONF_FILES] = "files",
[DNS_NSSCONF_DNS] = "dns",
[DNS_NSSCONF_MDNS] = "mdns",
};
return (k >= 0 && k < (int)lengthof(map))? (map[k]? map[k] : "") : "";
} /* dns_nssconf_k2s() */
DNS_PRAGMA_POP
int dns_nssconf_loadfile(struct dns_resolv_conf *resconf, FILE *fp) {
enum dns_nssconf_keyword source, status, action;
char lookup[sizeof resconf->lookup] = "", *lp;
struct dns_anyconf cf;
size_t i;
int error;
while (!feof(fp) && !ferror(fp)) {
dns_anyconf_reset(&cf);
dns_anyconf_skip("%s", fp);
if (!dns_anyconf_scan(&cf, "%w_", fp, &error))
goto nextent;
if (DNS_NSSCONF_HOSTS != dns_nssconf_keyword(cf.token[0]))
goto nextent;
dns_anyconf_pop(&cf);
if (!dns_anyconf_skip(": \t", fp))
goto nextent;
*(lp = lookup) = '\0';
while (dns_anyconf_scan(&cf, "%w_", fp, &error)) {
dns_anyconf_skip(" \t", fp);
if ('[' == dns_anyconf_peek(fp)) {
dns_anyconf_skip("[! \t", fp);
while (dns_anyconf_scan(&cf, "%w_", fp, &error)) {
dns_anyconf_skip("= \t", fp);
if (!dns_anyconf_scan(&cf, "%w_", fp, &error)) {
dns_anyconf_pop(&cf); /* discard status */
dns_anyconf_skip("^#;]\n", fp); /* skip to end of criteria */
break;
}
dns_anyconf_skip(" \t", fp);
}
dns_anyconf_skip("] \t", fp);
}
if ((size_t)(endof(lookup) - lp) < cf.count + 1) /* +1 for '\0' */
goto nextsrc;
source = dns_nssconf_keyword(cf.token[0]);
switch (source) {
case DNS_NSSCONF_DNS:
case DNS_NSSCONF_MDNS:
case DNS_NSSCONF_FILES:
*lp++ = dns_nssconf_k2c(source);
break;
default:
goto nextsrc;
}
for (i = 1; i + 1 < cf.count; i += 2) {
status = dns_nssconf_keyword(cf.token[i]);
action = dns_nssconf_keyword(cf.token[i + 1]);
switch (status) {
case DNS_NSSCONF_SUCCESS:
case DNS_NSSCONF_NOTFOUND:
case DNS_NSSCONF_UNAVAIL:
case DNS_NSSCONF_TRYAGAIN:
*lp++ = dns_nssconf_k2c(status);
break;
default:
continue;
}
switch (action) {
case DNS_NSSCONF_CONTINUE:
case DNS_NSSCONF_RETURN:
break;
default:
action = (status == DNS_NSSCONF_SUCCESS)
? DNS_NSSCONF_RETURN
: DNS_NSSCONF_CONTINUE;
break;
}
*lp++ = dns_nssconf_k2c(action);
}
nextsrc:
*lp = '\0';
dns_anyconf_reset(&cf);
}
nextent:
dns_anyconf_skip("^\n", fp);
}
if (*lookup)
strncpy(resconf->lookup, lookup, sizeof resconf->lookup);
return 0;
} /* dns_nssconf_loadfile() */
int dns_nssconf_loadpath(struct dns_resolv_conf *resconf, const char *path) {
FILE *fp;
int error;
if (!(fp = dns_fopen(path, "rt", &error)))
return error;
error = dns_nssconf_loadfile(resconf, fp);
fclose(fp);
return error;
} /* dns_nssconf_loadpath() */
struct dns_nssconf_source {
enum dns_nssconf_keyword source, success, notfound, unavail, tryagain;
}; /* struct dns_nssconf_source */
typedef unsigned dns_nssconf_i;
static inline int dns_nssconf_peek(const struct dns_resolv_conf *resconf, dns_nssconf_i state) {
return (state < lengthof(resconf->lookup) && resconf->lookup[state])? resconf->lookup[state] : 0;
} /* dns_nssconf_peek() */
static _Bool dns_nssconf_next(struct dns_nssconf_source *src, const struct dns_resolv_conf *resconf, dns_nssconf_i *state) {
int source, status, action;
src->source = DNS_NSSCONF_INVALID;
src->success = DNS_NSSCONF_RETURN;
src->notfound = DNS_NSSCONF_CONTINUE;
src->unavail = DNS_NSSCONF_CONTINUE;
src->tryagain = DNS_NSSCONF_CONTINUE;
while ((source = dns_nssconf_peek(resconf, *state))) {
source = dns_nssconf_c2k(source);
++*state;
switch (source) {
case DNS_NSSCONF_FILES:
case DNS_NSSCONF_DNS:
case DNS_NSSCONF_MDNS:
src->source = source;
break;
default:
continue;
}
while ((status = dns_nssconf_peek(resconf, *state)) && (action = dns_nssconf_peek(resconf, *state + 1))) {
status = dns_nssconf_c2k(status);
action = dns_nssconf_c2k(action);
switch (action) {
case DNS_NSSCONF_RETURN:
case DNS_NSSCONF_CONTINUE:
break;
default:
goto done;
}
switch (status) {
case DNS_NSSCONF_SUCCESS:
src->success = action;
break;
case DNS_NSSCONF_NOTFOUND:
src->notfound = action;
break;
case DNS_NSSCONF_UNAVAIL:
src->unavail = action;
break;
case DNS_NSSCONF_TRYAGAIN:
src->tryagain = action;
break;
default:
goto done;
}
*state += 2;
}
break;
}
done:
return src->source != DNS_NSSCONF_INVALID;
} /* dns_nssconf_next() */
static int dns_nssconf_dump_status(int status, int action, unsigned *count, FILE *fp) {
switch (status) {
case DNS_NSSCONF_SUCCESS:
if (action == DNS_NSSCONF_RETURN)
return 0;
break;
default:
if (action == DNS_NSSCONF_CONTINUE)
return 0;
break;
}
fputc(' ', fp);
if (!*count)
fputc('[', fp);
fprintf(fp, "%s=%s", dns_nssconf_k2s(status), dns_nssconf_k2s(action));
++*count;
return 0;
} /* dns_nssconf_dump_status() */
int dns_nssconf_dump(struct dns_resolv_conf *resconf, FILE *fp) {
struct dns_nssconf_source src;
dns_nssconf_i i = 0;
fputs("hosts:", fp);
while (dns_nssconf_next(&src, resconf, &i)) {
unsigned n = 0;
fprintf(fp, " %s", dns_nssconf_k2s(src.source));
dns_nssconf_dump_status(DNS_NSSCONF_SUCCESS, src.success, &n, fp);
dns_nssconf_dump_status(DNS_NSSCONF_NOTFOUND, src.notfound, &n, fp);
dns_nssconf_dump_status(DNS_NSSCONF_UNAVAIL, src.unavail, &n, fp);
dns_nssconf_dump_status(DNS_NSSCONF_TRYAGAIN, src.tryagain, &n, fp);
if (n)
fputc(']', fp);
}
fputc('\n', fp);
return 0;
} /* dns_nssconf_dump() */
int dns_resconf_setiface(struct dns_resolv_conf *resconf, const char *addr, unsigned short port) {
int af = (strchr(addr, ':'))? AF_INET6 : AF_INET;
int error;
memset(&resconf->iface, 0, sizeof (struct sockaddr_storage));
if ((error = dns_pton(af, addr, dns_sa_addr(af, &resconf->iface, NULL))))
return error;
*dns_sa_port(af, &resconf->iface) = htons(port);
resconf->iface.ss_family = af;
return 0;
} /* dns_resconf_setiface() */
#define DNS_SM_RESTORE \
do { \
pc = 0xff & (*state >> 0); \
srchi = 0xff & (*state >> 8); \
ndots = 0xff & (*state >> 16); \
} while (0)
#define DNS_SM_SAVE \
do { \
*state = ((0xff & pc) << 0) \
| ((0xff & srchi) << 8) \
| ((0xff & ndots) << 16); \
} while (0)
size_t dns_resconf_search(void *dst, size_t lim, const void *qname, size_t qlen, struct dns_resolv_conf *resconf, dns_resconf_i_t *state) {
unsigned pc, srchi, ndots, len;
DNS_SM_ENTER;
/* if FQDN then return as-is and finish */
if (dns_d_isanchored(qname, qlen)) {
len = dns_d_anchor(dst, lim, qname, qlen);
DNS_SM_YIELD(len);
DNS_SM_EXIT;
}
ndots = dns_d_ndots(qname, qlen);
if (ndots >= resconf->options.ndots) {
len = dns_d_anchor(dst, lim, qname, qlen);
DNS_SM_YIELD(len);
}
while (srchi < lengthof(resconf->search) && resconf->search[srchi][0]) {
struct dns_buf buf = DNS_B_INTO(dst, lim);
const char *dn = resconf->search[srchi++];
dns_b_put(&buf, qname, qlen);
dns_b_putc(&buf, '.');
dns_b_puts(&buf, dn);
if (!dns_d_isanchored(dn, strlen(dn)))
dns_b_putc(&buf, '.');
len = dns_b_strllen(&buf);
DNS_SM_YIELD(len);
}
if (ndots < resconf->options.ndots) {
len = dns_d_anchor(dst, lim, qname, qlen);
DNS_SM_YIELD(len);
}
DNS_SM_LEAVE;
return dns_strlcpy(dst, "", lim);
} /* dns_resconf_search() */
#undef DNS_SM_SAVE
#undef DNS_SM_RESTORE
int dns_resconf_dump(struct dns_resolv_conf *resconf, FILE *fp) {
unsigned i;
int af;
for (i = 0; i < lengthof(resconf->nameserver) && (af = resconf->nameserver[i].ss_family) != AF_UNSPEC; i++) {
char addr[INET6_ADDRSTRLEN + 1] = "[INVALID]";
unsigned short port;
dns_inet_ntop(af, dns_sa_addr(af, &resconf->nameserver[i], NULL), addr, sizeof addr);
port = ntohs(*dns_sa_port(af, &resconf->nameserver[i]));
if (port == 53)
fprintf(fp, "nameserver %s\n", addr);
else
fprintf(fp, "nameserver [%s]:%hu\n", addr, port);
}
fprintf(fp, "search");
for (i = 0; i < lengthof(resconf->search) && resconf->search[i][0]; i++)
fprintf(fp, " %s", resconf->search[i]);
fputc('\n', fp);
fputs("; ", fp);
dns_nssconf_dump(resconf, fp);
fprintf(fp, "lookup");
for (i = 0; i < lengthof(resconf->lookup) && resconf->lookup[i]; i++) {
switch (resconf->lookup[i]) {
case 'b':
fprintf(fp, " bind"); break;
case 'f':
fprintf(fp, " file"); break;
case 'c':
fprintf(fp, " cache"); break;
}
}
fputc('\n', fp);
fprintf(fp, "options ndots:%u timeout:%u attempts:%u", resconf->options.ndots, resconf->options.timeout, resconf->options.attempts);
if (resconf->options.edns0)
fprintf(fp, " edns0");
if (resconf->options.rotate)
fprintf(fp, " rotate");
if (resconf->options.recurse)
fprintf(fp, " recurse");
if (resconf->options.smart)
fprintf(fp, " smart");
switch (resconf->options.tcp) {
case DNS_RESCONF_TCP_ENABLE:
break;
case DNS_RESCONF_TCP_ONLY:
fprintf(fp, " tcp");
break;
case DNS_RESCONF_TCP_SOCKS:
fprintf(fp, " tcp:socks");
break;
case DNS_RESCONF_TCP_DISABLE:
fprintf(fp, " tcp:disable");
break;
}
fputc('\n', fp);
if ((af = resconf->iface.ss_family) != AF_UNSPEC) {
char addr[INET6_ADDRSTRLEN + 1] = "[INVALID]";
dns_inet_ntop(af, dns_sa_addr(af, &resconf->iface, NULL), addr, sizeof addr);
fprintf(fp, "interface %s %hu\n", addr, ntohs(*dns_sa_port(af, &resconf->iface)));
}
return 0;
} /* dns_resconf_dump() */
/*
* H I N T S E R V E R R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct dns_hints_soa {
unsigned char zone[DNS_D_MAXNAME + 1];
struct {
struct sockaddr_storage ss;
unsigned priority;
} addrs[16];
unsigned count;
struct dns_hints_soa *next;
}; /* struct dns_hints_soa */
struct dns_hints {
dns_atomic_t refcount;
struct dns_hints_soa *head;
}; /* struct dns_hints */
struct dns_hints *dns_hints_open(struct dns_resolv_conf *resconf, int *error) {
static const struct dns_hints H_initializer;
struct dns_hints *H;
(void)resconf;
if (!(H = malloc(sizeof *H)))
goto syerr;
*H = H_initializer;
dns_hints_acquire(H);
return H;
syerr:
*error = dns_syerr();
free(H);
return 0;
} /* dns_hints_open() */
void dns_hints_close(struct dns_hints *H) {
struct dns_hints_soa *soa, *nxt;
if (!H || 1 != dns_hints_release(H))
return /* void */;
for (soa = H->head; soa; soa = nxt) {
nxt = soa->next;
free(soa);
}
free(H);
return /* void */;
} /* dns_hints_close() */
dns_refcount_t dns_hints_acquire(struct dns_hints *H) {
return dns_atomic_fetch_add(&H->refcount);
} /* dns_hints_acquire() */
dns_refcount_t dns_hints_release(struct dns_hints *H) {
return dns_atomic_fetch_sub(&H->refcount);
} /* dns_hints_release() */
struct dns_hints *dns_hints_mortal(struct dns_hints *hints) {
if (hints)
dns_hints_release(hints);
return hints;
} /* dns_hints_mortal() */
struct dns_hints *dns_hints_local(struct dns_resolv_conf *resconf, int *error_) {
struct dns_hints *hints = 0;
int error;
if (resconf)
dns_resconf_acquire(resconf);
else if (!(resconf = dns_resconf_local(&error)))
goto error;
if (!(hints = dns_hints_open(resconf, &error)))
goto error;
error = 0;
if (0 == dns_hints_insert_resconf(hints, ".", resconf, &error) && error)
goto error;
dns_resconf_close(resconf);
return hints;
error:
*error_ = error;
dns_resconf_close(resconf);
dns_hints_close(hints);
return 0;
} /* dns_hints_local() */
struct dns_hints *dns_hints_root(struct dns_resolv_conf *resconf, int *error_) {
static const struct {
int af;
char addr[INET6_ADDRSTRLEN];
} root_hints[] = {
{ AF_INET, "198.41.0.4" }, /* A.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:503:ba3e::2:30" }, /* A.ROOT-SERVERS.NET. */
{ AF_INET, "192.228.79.201" }, /* B.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:84::b" }, /* B.ROOT-SERVERS.NET. */
{ AF_INET, "192.33.4.12" }, /* C.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:2::c" }, /* C.ROOT-SERVERS.NET. */
{ AF_INET, "199.7.91.13" }, /* D.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:2d::d" }, /* D.ROOT-SERVERS.NET. */
{ AF_INET, "192.203.230.10" }, /* E.ROOT-SERVERS.NET. */
{ AF_INET, "192.5.5.241" }, /* F.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:2f::f" }, /* F.ROOT-SERVERS.NET. */
{ AF_INET, "192.112.36.4" }, /* G.ROOT-SERVERS.NET. */
{ AF_INET, "128.63.2.53" }, /* H.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:1::803f:235" }, /* H.ROOT-SERVERS.NET. */
{ AF_INET, "192.36.148.17" }, /* I.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:7FE::53" }, /* I.ROOT-SERVERS.NET. */
{ AF_INET, "192.58.128.30" }, /* J.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:503:c27::2:30" }, /* J.ROOT-SERVERS.NET. */
{ AF_INET, "193.0.14.129" }, /* K.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:7FD::1" }, /* K.ROOT-SERVERS.NET. */
{ AF_INET, "199.7.83.42" }, /* L.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:500:3::42" }, /* L.ROOT-SERVERS.NET. */
{ AF_INET, "202.12.27.33" }, /* M.ROOT-SERVERS.NET. */
{ AF_INET6, "2001:DC3::35" }, /* M.ROOT-SERVERS.NET. */
};
struct dns_hints *hints = 0;
struct sockaddr_storage ss;
unsigned i;
int error, af;
if (!(hints = dns_hints_open(resconf, &error)))
goto error;
for (i = 0; i < lengthof(root_hints); i++) {
af = root_hints[i].af;
memset(&ss, 0, sizeof ss);
if ((error = dns_pton(af, root_hints[i].addr, dns_sa_addr(af, &ss, NULL))))
goto error;
*dns_sa_port(af, &ss) = htons(53);
ss.ss_family = af;
if ((error = dns_hints_insert(hints, ".", (struct sockaddr *)&ss, 1)))
goto error;
}
return hints;
error:
*error_ = error;
dns_hints_close(hints);
return 0;
} /* dns_hints_root() */
static struct dns_hints_soa *dns_hints_fetch(struct dns_hints *H, const char *zone) {
struct dns_hints_soa *soa;
for (soa = H->head; soa; soa = soa->next) {
if (0 == strcasecmp(zone, (char *)soa->zone))
return soa;
}
return 0;
} /* dns_hints_fetch() */
int dns_hints_insert(struct dns_hints *H, const char *zone, const struct sockaddr *sa, unsigned priority) {
static const struct dns_hints_soa soa_initializer;
struct dns_hints_soa *soa;
unsigned i;
if (!(soa = dns_hints_fetch(H, zone))) {
if (!(soa = malloc(sizeof *soa)))
return dns_syerr();
*soa = soa_initializer;
dns_strlcpy((char *)soa->zone, zone, sizeof soa->zone);
soa->next = H->head;
H->head = soa;
}
i = soa->count % lengthof(soa->addrs);
memcpy(&soa->addrs[i].ss, sa, dns_sa_len(sa));
soa->addrs[i].priority = DNS_PP_MAX(1, priority);
if (soa->count < lengthof(soa->addrs))
soa->count++;
return 0;
} /* dns_hints_insert() */
static _Bool dns_hints_isinaddr_any(const void *sa) {
struct in_addr *addr;
if (dns_sa_family(sa) != AF_INET)
return 0;
addr = dns_sa_addr(AF_INET, sa, NULL);
return addr->s_addr == htonl(INADDR_ANY);
}
unsigned dns_hints_insert_resconf(struct dns_hints *H, const char *zone, const struct dns_resolv_conf *resconf, int *error_) {
unsigned i, n, p;
int error;
for (i = 0, n = 0, p = 1; i < lengthof(resconf->nameserver) && resconf->nameserver[i].ss_family != AF_UNSPEC; i++, n++) {
union { struct sockaddr_in sin; } tmp;
struct sockaddr *ns;
/*
* dns_resconf_open initializes nameserver[0] to INADDR_ANY.
*
* Traditionally the semantics of 0.0.0.0 meant the default
* interface, which evolved to mean the loopback interface.
* See comment block preceding resolv/res_init.c:res_init in
* glibc 2.23. As of 2.23, glibc no longer translates
* 0.0.0.0 despite the code comment, but it does default to
* 127.0.0.1 when no nameservers are present.
*
* BIND9 as of 9.10.3 still translates 0.0.0.0 to 127.0.0.1.
* See lib/lwres/lwconfig.c:lwres_create_addr and the
* convert_zero flag. 127.0.0.1 is also the default when no
* nameservers are present.
*/
if (dns_hints_isinaddr_any(&resconf->nameserver[i])) {
memcpy(&tmp.sin, &resconf->nameserver[i], sizeof tmp.sin);
tmp.sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
ns = (struct sockaddr *)&tmp.sin;
} else {
ns = (struct sockaddr *)&resconf->nameserver[i];
}
if ((error = dns_hints_insert(H, zone, ns, p)))
goto error;
p += !resconf->options.rotate;
}
return n;
error:
*error_ = error;
return n;
} /* dns_hints_insert_resconf() */
static int dns_hints_i_cmp(unsigned a, unsigned b, struct dns_hints_i *i, struct dns_hints_soa *soa) {
int cmp;
if ((cmp = soa->addrs[a].priority - soa->addrs[b].priority))
return cmp;
return dns_k_shuffle16(a, i->state.seed) - dns_k_shuffle16(b, i->state.seed);
} /* dns_hints_i_cmp() */
static unsigned dns_hints_i_start(struct dns_hints_i *i, struct dns_hints_soa *soa) {
unsigned p0, p;
p0 = 0;
for (p = 1; p < soa->count; p++) {
if (dns_hints_i_cmp(p, p0, i, soa) < 0)
p0 = p;
}
return p0;
} /* dns_hints_i_start() */
static unsigned dns_hints_i_skip(unsigned p0, struct dns_hints_i *i, struct dns_hints_soa *soa) {
unsigned pZ, p;
for (pZ = 0; pZ < soa->count; pZ++) {
if (dns_hints_i_cmp(pZ, p0, i, soa) > 0)
goto cont;
}
return soa->count;
cont:
for (p = pZ + 1; p < soa->count; p++) {
if (dns_hints_i_cmp(p, p0, i, soa) <= 0)
continue;
if (dns_hints_i_cmp(p, pZ, i, soa) >= 0)
continue;
pZ = p;
}
return pZ;
} /* dns_hints_i_skip() */
static struct dns_hints_i *dns_hints_i_init(struct dns_hints_i *i, struct dns_hints *hints) {
static const struct dns_hints_i i_initializer;
struct dns_hints_soa *soa;
i->state = i_initializer.state;
do {
i->state.seed = dns_random();
} while (0 == i->state.seed);
if ((soa = dns_hints_fetch(hints, i->zone))) {
i->state.next = dns_hints_i_start(i, soa);
}
return i;
} /* dns_hints_i_init() */
unsigned dns_hints_grep(struct sockaddr **sa, socklen_t *sa_len, unsigned lim, struct dns_hints_i *i, struct dns_hints *H) {
struct dns_hints_soa *soa;
unsigned n;
if (!(soa = dns_hints_fetch(H, i->zone)))
return 0;
n = 0;
while (i->state.next < soa->count && n < lim) {
*sa = (struct sockaddr *)&soa->addrs[i->state.next].ss;
*sa_len = dns_sa_len(*sa);
sa++;
sa_len++;
n++;
i->state.next = dns_hints_i_skip(i->state.next, i, soa);
}
return n;
} /* dns_hints_grep() */
struct dns_packet *dns_hints_query(struct dns_hints *hints, struct dns_packet *Q, int *error_) {
struct dns_packet *A, *P;
struct dns_rr rr;
char zone[DNS_D_MAXNAME + 1];
size_t zlen;
struct dns_hints_i i;
struct sockaddr *sa;
socklen_t slen;
int error;
if (!dns_rr_grep(&rr, 1, dns_rr_i_new(Q, .section = DNS_S_QUESTION), Q, &error))
goto error;
if (!(zlen = dns_d_expand(zone, sizeof zone, rr.dn.p, Q, &error)))
goto error;
else if (zlen >= sizeof zone)
goto toolong;
P = dns_p_new(512);
dns_header(P)->qr = 1;
if ((error = dns_rr_copy(P, &rr, Q)))
goto error;
if ((error = dns_p_push(P, DNS_S_AUTHORITY, ".", strlen("."), DNS_T_NS, DNS_C_IN, 0, "hints.local.")))
goto error;
do {
i.zone = zone;
dns_hints_i_init(&i, hints);
while (dns_hints_grep(&sa, &slen, 1, &i, hints)) {
int af = sa->sa_family;
int rtype = (af == AF_INET6)? DNS_T_AAAA : DNS_T_A;
if ((error = dns_p_push(P, DNS_S_ADDITIONAL, "hints.local.", strlen("hints.local."), rtype, DNS_C_IN, 0, dns_sa_addr(af, sa, NULL))))
goto error;
}
} while ((zlen = dns_d_cleave(zone, sizeof zone, zone, zlen)));
if (!(A = dns_p_copy(dns_p_make(P->end, &error), P)))
goto error;
return A;
toolong:
error = DNS_EILLEGAL;
error:
*error_ = error;
return 0;
} /* dns_hints_query() */
/** ugly hack to support specifying ports other than 53 in resolv.conf. */
static unsigned short dns_hints_port(struct dns_hints *hints, int af, void *addr) {
struct dns_hints_soa *soa;
void *addrsoa;
socklen_t addrlen;
unsigned short port;
unsigned i;
for (soa = hints->head; soa; soa = soa->next) {
for (i = 0; i < soa->count; i++) {
if (af != soa->addrs[i].ss.ss_family)
continue;
if (!(addrsoa = dns_sa_addr(af, &soa->addrs[i].ss, &addrlen)))
continue;
if (memcmp(addr, addrsoa, addrlen))
continue;
port = *dns_sa_port(af, &soa->addrs[i].ss);
return (port)? port : htons(53);
}
}
return htons(53);
} /* dns_hints_port() */
int dns_hints_dump(struct dns_hints *hints, FILE *fp) {
struct dns_hints_soa *soa;
char addr[INET6_ADDRSTRLEN];
unsigned i;
int af, error;
for (soa = hints->head; soa; soa = soa->next) {
fprintf(fp, "ZONE \"%s\"\n", soa->zone);
for (i = 0; i < soa->count; i++) {
af = soa->addrs[i].ss.ss_family;
if ((error = dns_ntop(af, dns_sa_addr(af, &soa->addrs[i].ss, NULL), addr, sizeof addr)))
return error;
fprintf(fp, "\t(%d) [%s]:%hu\n", (int)soa->addrs[i].priority, addr, ntohs(*dns_sa_port(af, &soa->addrs[i].ss)));
}
}
return 0;
} /* dns_hints_dump() */
/*
* C A C H E R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
static dns_refcount_t dns_cache_acquire(struct dns_cache *cache) {
return dns_atomic_fetch_add(&cache->_.refcount);
} /* dns_cache_acquire() */
static dns_refcount_t dns_cache_release(struct dns_cache *cache) {
return dns_atomic_fetch_sub(&cache->_.refcount);
} /* dns_cache_release() */
static struct dns_packet *dns_cache_query(struct dns_packet *query, struct dns_cache *cache, int *error) {
(void)query;
(void)cache;
(void)error;
return NULL;
} /* dns_cache_query() */
static int dns_cache_submit(struct dns_packet *query, struct dns_cache *cache) {
(void)query;
(void)cache;
return 0;
} /* dns_cache_submit() */
static int dns_cache_check(struct dns_cache *cache) {
(void)cache;
return 0;
} /* dns_cache_check() */
static struct dns_packet *dns_cache_fetch(struct dns_cache *cache, int *error) {
(void)cache;
(void)error;
return NULL;
} /* dns_cache_fetch() */
static int dns_cache_pollfd(struct dns_cache *cache) {
(void)cache;
return -1;
} /* dns_cache_pollfd() */
static short dns_cache_events(struct dns_cache *cache) {
(void)cache;
return 0;
} /* dns_cache_events() */
static void dns_cache_clear(struct dns_cache *cache) {
(void)cache;
return;
} /* dns_cache_clear() */
struct dns_cache *dns_cache_init(struct dns_cache *cache) {
static const struct dns_cache c_init = {
.acquire = &dns_cache_acquire,
.release = &dns_cache_release,
.query = &dns_cache_query,
.submit = &dns_cache_submit,
.check = &dns_cache_check,
.fetch = &dns_cache_fetch,
.pollfd = &dns_cache_pollfd,
.events = &dns_cache_events,
.clear = &dns_cache_clear,
._ = { .refcount = 1, },
};
*cache = c_init;
return cache;
} /* dns_cache_init() */
void dns_cache_close(struct dns_cache *cache) {
if (cache)
cache->release(cache);
} /* dns_cache_close() */
/*
* S O C K E T R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
static void dns_socketclose(int *fd, const struct dns_options *opts) {
if (opts && opts->closefd.cb)
opts->closefd.cb(fd, opts->closefd.arg);
if (*fd != -1) {
#if _WIN32
closesocket(*fd);
#else
close(*fd);
#endif
*fd = -1;
}
} /* dns_socketclose() */
#ifndef HAVE_IOCTLSOCKET
#define HAVE_IOCTLSOCKET (_WIN32 || _WIN64)
#endif
#ifndef HAVE_SOCK_CLOEXEC
#ifdef SOCK_CLOEXEC
#define HAVE_SOCK_CLOEXEC 1
#else
#define HAVE_SOCK_CLOEXEC 0
#endif
#endif
#ifndef HAVE_SOCK_NONBLOCK
#ifdef SOCK_NONBLOCK
#define HAVE_SOCK_NONBLOCK 1
#else
#define HAVE_SOCK_NONBLOCK 0
#endif
#endif
#define DNS_SO_MAXTRY 7
static int dns_socket(struct sockaddr *local, int type, int *error_) {
int fd = -1, flags, error;
#if defined FIONBIO
unsigned long opt;
#endif
flags = 0;
#if HAVE_SOCK_CLOEXEC
flags |= SOCK_CLOEXEC;
#endif
#if HAVE_SOCK_NONBLOCK
flags |= SOCK_NONBLOCK;
#endif
if (-1 == (fd = socket(local->sa_family, type|flags, 0)))
goto soerr;
#if defined F_SETFD && !HAVE_SOCK_CLOEXEC
if (-1 == fcntl(fd, F_SETFD, 1))
goto syerr;
#endif
#if defined O_NONBLOCK && !HAVE_SOCK_NONBLOCK
if (-1 == (flags = fcntl(fd, F_GETFL)))
goto syerr;
if (-1 == fcntl(fd, F_SETFL, flags | O_NONBLOCK))
goto syerr;
#elif defined FIONBIO && HAVE_IOCTLSOCKET
opt = 1;
if (0 != ioctlsocket(fd, FIONBIO, &opt))
goto soerr;
#endif
#if defined SO_NOSIGPIPE
if (type != SOCK_DGRAM) {
if (0 != setsockopt(fd, SOL_SOCKET, SO_NOSIGPIPE, &(int){ 1 }, sizeof (int)))
goto soerr;
}
#endif
if (local->sa_family != AF_INET && local->sa_family != AF_INET6)
return fd;
if (type != SOCK_DGRAM)
return fd;
#define LEAVE_SELECTION_OF_PORT_TO_KERNEL
#if !defined(LEAVE_SELECTION_OF_PORT_TO_KERNEL)
/*
* FreeBSD, Linux, OpenBSD, OS X, and Solaris use random ports by
* default. Though the ephemeral range is quite small on OS X
* (49152-65535 on 10.10) and Linux (32768-60999 on 4.4.0, Ubuntu
* Xenial). See also RFC 6056.
*
* TODO: Optionally rely on the kernel to select a random port.
*/
if (*dns_sa_port(local->sa_family, local) == 0) {
struct sockaddr_storage tmp;
unsigned i, port;
memcpy(&tmp, local, dns_sa_len(local));
for (i = 0; i < DNS_SO_MAXTRY; i++) {
port = 1025 + (dns_random() % 64510);
*dns_sa_port(tmp.ss_family, &tmp) = htons(port);
if (0 == bind(fd, (struct sockaddr *)&tmp, dns_sa_len(&tmp)))
return fd;
}
/* NB: continue to next bind statement */
}
#endif
if (0 == bind(fd, local, dns_sa_len(local)))
return fd;
/* FALL THROUGH */
soerr:
error = dns_soerr();
goto error;
#if (defined F_SETFD && !HAVE_SOCK_CLOEXEC) || (defined O_NONBLOCK && !HAVE_SOCK_NONBLOCK)
syerr:
error = dns_syerr();
goto error;
#endif
error:
*error_ = error;
dns_socketclose(&fd, NULL);
return -1;
} /* dns_socket() */
enum {
DNS_SO_UDP_INIT = 1,
DNS_SO_UDP_CONN,
DNS_SO_UDP_SEND,
DNS_SO_UDP_RECV,
DNS_SO_UDP_DONE,
DNS_SO_TCP_INIT,
DNS_SO_TCP_CONN,
DNS_SO_TCP_SEND,
DNS_SO_TCP_RECV,
DNS_SO_TCP_DONE,
DNS_SO_SOCKS_INIT,
DNS_SO_SOCKS_CONN,
DNS_SO_SOCKS_HELLO_SEND,
DNS_SO_SOCKS_HELLO_RECV,
DNS_SO_SOCKS_AUTH_SEND,
DNS_SO_SOCKS_AUTH_RECV,
DNS_SO_SOCKS_REQUEST_PREPARE,
DNS_SO_SOCKS_REQUEST_SEND,
DNS_SO_SOCKS_REQUEST_RECV,
DNS_SO_SOCKS_REQUEST_RECV_V6,
DNS_SO_SOCKS_HANDSHAKE_DONE,
};
struct dns_socket {
struct dns_options opts;
int udp;
int tcp;
int *old;
unsigned onum, olim;
int type;
struct sockaddr_storage local, remote;
struct dns_k_permutor qids;
struct dns_stat stat;
struct dns_trace *trace;
/*
* NOTE: dns_so_reset() zeroes everything from here down.
*/
int state;
unsigned short qid;
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
enum dns_type qtype;
enum dns_class qclass;
struct dns_packet *query;
size_t qout;
/* During a SOCKS handshake the query is temporarily stored
* here. */
struct dns_packet *query_backup;
struct dns_clock elapsed;
struct dns_packet *answer;
size_t alen, apos;
}; /* struct dns_socket */
/*
* NOTE: Actual closure delayed so that kqueue(2) and epoll(2) callers have
* a chance to recognize a state change after installing a persistent event
* and where sequential descriptors with the same integer value returned
* from _pollfd() would be ambiguous. See dns_so_closefds().
*/
static int dns_so_closefd(struct dns_socket *so, int *fd) {
int error;
if (*fd == -1)
return 0;
if (so->opts.closefd.cb) {
if ((error = so->opts.closefd.cb(fd, so->opts.closefd.arg))) {
return error;
} else if (*fd == -1)
return 0;
}
if (!(so->onum < so->olim)) {
unsigned olim = DNS_PP_MAX(4, so->olim * 2);
void *old;
if (!(old = realloc(so->old, sizeof so->old[0] * olim)))
return dns_syerr();
so->old = old;
so->olim = olim;
}
so->old[so->onum++] = *fd;
*fd = -1;
return 0;
} /* dns_so_closefd() */
#define DNS_SO_CLOSE_UDP 0x01
#define DNS_SO_CLOSE_TCP 0x02
#define DNS_SO_CLOSE_OLD 0x04
#define DNS_SO_CLOSE_ALL (DNS_SO_CLOSE_UDP|DNS_SO_CLOSE_TCP|DNS_SO_CLOSE_OLD)
static void dns_so_closefds(struct dns_socket *so, int which) {
if (DNS_SO_CLOSE_UDP & which)
dns_socketclose(&so->udp, &so->opts);
if (DNS_SO_CLOSE_TCP & which)
dns_socketclose(&so->tcp, &so->opts);
if (DNS_SO_CLOSE_OLD & which) {
unsigned i;
for (i = 0; i < so->onum; i++)
dns_socketclose(&so->old[i], &so->opts);
so->onum = 0;
free(so->old);
so->old = 0;
so->olim = 0;
}
} /* dns_so_closefds() */
static void dns_so_destroy(struct dns_socket *);
static struct dns_socket *dns_so_init(struct dns_socket *so, const struct sockaddr *local, int type, const struct dns_options *opts, int *error) {
static const struct dns_socket so_initializer = { .opts = DNS_OPTS_INITIALIZER, .udp = -1, .tcp = -1, };
*so = so_initializer;
so->type = type;
if (opts)
so->opts = *opts;
if (local)
memcpy(&so->local, local, dns_sa_len(local));
if (-1 == (so->udp = dns_socket((struct sockaddr *)&so->local, SOCK_DGRAM, error)))
goto error;
dns_k_permutor_init(&so->qids, 1, 65535);
return so;
error:
dns_so_destroy(so);
return 0;
} /* dns_so_init() */
struct dns_socket *dns_so_open(const struct sockaddr *local, int type, const struct dns_options *opts, int *error) {
struct dns_socket *so;
if (!(so = malloc(sizeof *so)))
goto syerr;
if (!dns_so_init(so, local, type, opts, error))
goto error;
return so;
syerr:
*error = dns_syerr();
error:
dns_so_close(so);
return 0;
} /* dns_so_open() */
static void dns_so_destroy(struct dns_socket *so) {
dns_so_reset(so);
dns_so_closefds(so, DNS_SO_CLOSE_ALL);
dns_trace_close(so->trace);
} /* dns_so_destroy() */
void dns_so_close(struct dns_socket *so) {
if (!so)
return;
dns_so_destroy(so);
free(so);
} /* dns_so_close() */
void dns_so_reset(struct dns_socket *so) {
dns_p_setptr(&so->answer, NULL);
memset(&so->state, '\0', sizeof *so - offsetof(struct dns_socket, state));
} /* dns_so_reset() */
unsigned short dns_so_mkqid(struct dns_socket *so) {
return dns_k_permutor_step(&so->qids);
} /* dns_so_mkqid() */
#define DNS_SO_MINBUF 768
static int dns_so_newanswer(struct dns_socket *so, size_t len) {
size_t size = offsetof(struct dns_packet, data) + DNS_PP_MAX(len, DNS_SO_MINBUF);
void *p;
if (!(p = realloc(so->answer, size)))
return dns_syerr();
so->answer = dns_p_init(p, size);
return 0;
} /* dns_so_newanswer() */
int dns_so_submit(struct dns_socket *so, struct dns_packet *Q, struct sockaddr *host) {
struct dns_rr rr;
int error = DNS_EUNKNOWN;
dns_so_reset(so);
if ((error = dns_rr_parse(&rr, 12, Q)))
goto error;
if (!(so->qlen = dns_d_expand(so->qname, sizeof so->qname, rr.dn.p, Q, &error)))
goto error;
/*
* NOTE: Don't bail if expansion is too long; caller may be
* intentionally sending long names. However, we won't be able to
* verify it on return.
*/
so->qtype = rr.type;
so->qclass = rr.class;
if ((error = dns_so_newanswer(so, (Q->memo.opt.maxudp)? Q->memo.opt.maxudp : DNS_SO_MINBUF)))
goto syerr;
memcpy(&so->remote, host, dns_sa_len(host));
so->query = Q;
so->qout = 0;
dns_begin(&so->elapsed);
if (dns_header(so->query)->qid == 0)
dns_header(so->query)->qid = dns_so_mkqid(so);
so->qid = dns_header(so->query)->qid;
so->state = (so->opts.socks_host && so->opts.socks_host->ss_family) ? DNS_SO_SOCKS_INIT :
(so->type == SOCK_STREAM)? DNS_SO_TCP_INIT : DNS_SO_UDP_INIT;
so->stat.queries++;
dns_trace_so_submit(so->trace, Q, host, 0);
return 0;
syerr:
error = dns_syerr();
error:
dns_so_reset(so);
dns_trace_so_submit(so->trace, Q, host, error);
return error;
} /* dns_so_submit() */
static int dns_so_verify(struct dns_socket *so, struct dns_packet *P) {
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
struct dns_rr rr;
int error = -1;
if (P->end < 12)
goto reject;
if (so->qid != dns_header(P)->qid)
goto reject;
if (!dns_p_count(P, DNS_S_QD))
goto reject;
if (0 != dns_rr_parse(&rr, 12, P))
goto reject;
if (rr.type != so->qtype || rr.class != so->qclass)
goto reject;
if (!(qlen = dns_d_expand(qname, sizeof qname, rr.dn.p, P, &error)))
goto error;
else if (qlen >= sizeof qname || qlen != so->qlen)
goto reject;
if (0 != strcasecmp(so->qname, qname))
goto reject;
dns_trace_so_verify(so->trace, P, 0);
return 0;
reject:
error = DNS_EVERIFY;
error:
DNS_SHOW(P, "rejecting packet (%s)", dns_strerror(error));
dns_trace_so_verify(so->trace, P, error);
return error;
} /* dns_so_verify() */
static _Bool dns_so_tcp_keep(struct dns_socket *so) {
struct sockaddr_storage remote;
if (so->tcp == -1)
return 0;
if (0 != getpeername(so->tcp, (struct sockaddr *)&remote, &(socklen_t){ sizeof remote }))
return 0;
return 0 == dns_sa_cmp(&remote, &so->remote);
} /* dns_so_tcp_keep() */
/* Convenience functions for sending non-DNS data. */
/* Set up everything for sending LENGTH octets. Returns the buffer
for the data. */
static unsigned char *dns_so_tcp_send_buffer(struct dns_socket *so, size_t length) {
/* Skip the length octets, we are not doing DNS. */
so->qout = 2;
so->query->end = length;
return so->query->data;
}
/* Set up everything for receiving LENGTH octets. */
static void dns_so_tcp_recv_expect(struct dns_socket *so, size_t length) {
/* Skip the length octets, we are not doing DNS. */
so->apos = 2;
so->alen = length;
}
/* Returns the buffer containing the received data. */
static unsigned char *dns_so_tcp_recv_buffer(struct dns_socket *so) {
return so->answer->data;
}
#if defined __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warray-bounds"
#endif
static int dns_so_tcp_send(struct dns_socket *so) {
unsigned char *qsrc;
size_t qend;
int error;
size_t n;
so->query->data[-2] = 0xff & (so->query->end >> 8);
so->query->data[-1] = 0xff & (so->query->end >> 0);
qend = so->query->end + 2;
while (so->qout < qend) {
qsrc = &so->query->data[-2] + so->qout;
n = dns_send_nopipe(so->tcp, (void *)qsrc, qend - so->qout, 0, &error);
dns_trace_sys_send(so->trace, so->tcp, SOCK_STREAM, qsrc, n, error);
if (error)
return error;
so->qout += n;
so->stat.tcp.sent.bytes += n;
}
so->stat.tcp.sent.count++;
return 0;
} /* dns_so_tcp_send() */
static int dns_so_tcp_recv(struct dns_socket *so) {
unsigned char *asrc;
size_t aend, alen, n;
int error;
aend = so->alen + 2;
while (so->apos < aend) {
asrc = &so->answer->data[-2];
n = dns_recv(so->tcp, (void *)&asrc[so->apos], aend - so->apos, 0, &error);
dns_trace_sys_recv(so->trace, so->tcp, SOCK_STREAM, &asrc[so->apos], n, error);
if (error)
return error;
so->apos += n;
so->stat.tcp.rcvd.bytes += n;
if (so->alen == 0 && so->apos >= 2) {
alen = ((0xff & so->answer->data[-2]) << 8)
| ((0xff & so->answer->data[-1]) << 0);
if ((error = dns_so_newanswer(so, alen)))
return error;
so->alen = alen;
aend = alen + 2;
}
}
so->answer->end = so->alen;
so->stat.tcp.rcvd.count++;
return 0;
} /* dns_so_tcp_recv() */
#if __clang__
#pragma clang diagnostic pop
#endif
int dns_so_check(struct dns_socket *so) {
int error;
size_t n;
unsigned char *buffer;
retry:
switch (so->state) {
case DNS_SO_UDP_INIT:
if (so->remote.ss_family != so->local.ss_family) {
/* Family mismatch. Reinitialize. */
if ((error = dns_so_closefd(so, &so->udp)))
goto error;
if ((error = dns_so_closefd(so, &so->tcp)))
goto error;
/* If the user supplied an interface
statement, that is gone now. Sorry. */
memset(&so->local, 0, sizeof so->local);
so->local.ss_family = so->remote.ss_family;
if (-1 == (so->udp = dns_socket((struct sockaddr *)&so->local, SOCK_DGRAM, &error)))
goto error;
}
so->state++; /* FALL THROUGH */
case DNS_SO_UDP_CONN:
udp_connect_retry:
error = dns_connect(so->udp, (struct sockaddr *)&so->remote, dns_sa_len(&so->remote));
dns_trace_sys_connect(so->trace, so->udp, SOCK_DGRAM, (struct sockaddr *)&so->remote, error);
/* Linux returns EINVAL when address was bound to
localhost and it's external IP address now. */
if (error == EINVAL) {
struct sockaddr unspec_addr;
memset (&unspec_addr, 0, sizeof unspec_addr);
unspec_addr.sa_family = AF_UNSPEC;
connect(so->udp, &unspec_addr, sizeof unspec_addr);
goto udp_connect_retry;
} else if (error == ECONNREFUSED)
/* Error for previous socket operation may
be reserverd asynchronously. */
goto udp_connect_retry;
if (error)
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_UDP_SEND:
n = dns_send(so->udp, (void *)so->query->data, so->query->end, 0, &error);
dns_trace_sys_send(so->trace, so->udp, SOCK_DGRAM, so->query->data, n, error);
if (error)
goto error;
so->stat.udp.sent.bytes += n;
so->stat.udp.sent.count++;
so->state++; /* FALL THROUGH */
case DNS_SO_UDP_RECV:
n = dns_recv(so->udp, (void *)so->answer->data, so->answer->size, 0, &error);
dns_trace_sys_recv(so->trace, so->udp, SOCK_DGRAM, so->answer->data, n, error);
if (error)
goto error;
so->answer->end = n;
so->stat.udp.rcvd.bytes += n;
so->stat.udp.rcvd.count++;
if ((error = dns_so_verify(so, so->answer)))
goto trash;
so->state++; /* FALL THROUGH */
case DNS_SO_UDP_DONE:
if (!dns_header(so->answer)->tc || so->type == SOCK_DGRAM)
return 0;
so->state++; /* FALL THROUGH */
case DNS_SO_TCP_INIT:
if (so->remote.ss_family != so->local.ss_family) {
/* Family mismatch. Reinitialize. */
if ((error = dns_so_closefd(so, &so->udp)))
goto error;
if ((error = dns_so_closefd(so, &so->tcp)))
goto error;
/* If the user supplied an interface
statement, that is gone now. Sorry. */
memset(&so->local, 0, sizeof so->local);
so->local.ss_family = so->remote.ss_family;
}
if (dns_so_tcp_keep(so)) {
so->state = DNS_SO_TCP_SEND;
goto retry;
}
if ((error = dns_so_closefd(so, &so->tcp)))
goto error;
if (-1 == (so->tcp = dns_socket((struct sockaddr *)&so->local, SOCK_STREAM, &error)))
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_TCP_CONN:
error = dns_connect(so->tcp, (struct sockaddr *)&so->remote, dns_sa_len(&so->remote));
dns_trace_sys_connect(so->trace, so->tcp, SOCK_STREAM, (struct sockaddr *)&so->remote, error);
if (error && error != DNS_EISCONN)
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_TCP_SEND:
if ((error = dns_so_tcp_send(so)))
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_TCP_RECV:
if ((error = dns_so_tcp_recv(so)))
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_TCP_DONE:
/* close unless DNS_RESCONF_TCP_ONLY (see dns_res_tcp2type) */
if (so->type != SOCK_STREAM) {
if ((error = dns_so_closefd(so, &so->tcp)))
goto error;
}
if ((error = dns_so_verify(so, so->answer)))
goto error;
return 0;
case DNS_SO_SOCKS_INIT:
if ((error = dns_so_closefd(so, &so->tcp)))
goto error;
if (-1 == (so->tcp = dns_socket((struct sockaddr *)&so->local, SOCK_STREAM, &error)))
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_CONN: {
unsigned char method;
error = dns_connect(so->tcp, (struct sockaddr *)so->opts.socks_host, dns_sa_len(so->opts.socks_host));
dns_trace_sys_connect(so->trace, so->tcp, SOCK_STREAM, (struct sockaddr *)so->opts.socks_host, error);
if (error && error != DNS_EISCONN)
goto error;
/* We need to do a handshake with the SOCKS server,
* but the query is already in the buffer. Move it
* out of the way. */
dns_p_movptr(&so->query_backup, &so->query);
/* Create a new buffer for the handshake. */
dns_p_grow(&so->query);
/* Negotiate method. */
buffer = dns_so_tcp_send_buffer(so, 3);
buffer[0] = 5; /* RFC-1928 VER field. */
buffer[1] = 1; /* NMETHODS */
if (so->opts.socks_user)
method = 2; /* Method: username/password authentication. */
else
method = 0; /* Method: No authentication required. */
buffer[2] = method;
so->state++;
} /* FALL THROUGH */
case DNS_SO_SOCKS_HELLO_SEND:
if ((error = dns_so_tcp_send(so)))
goto error;
dns_so_tcp_recv_expect(so, 2);
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_HELLO_RECV: {
unsigned char method;
if ((error = dns_so_tcp_recv(so)))
goto error;
buffer = dns_so_tcp_recv_buffer(so);
method = so->opts.socks_user ? 2 : 0;
if (buffer[0] != 5 || buffer[1] != method) {
/* Socks server returned wrong version or does
not support our requested method. */
error = ENOTSUP; /* Fixme: Is there a better errno? */
goto error;
}
if (method == 0) {
/* No authentication, go ahead and send the
request. */
so->state = DNS_SO_SOCKS_REQUEST_PREPARE;
goto retry;
}
/* Prepare username/password sub-negotiation. */
if (! so->opts.socks_password) {
error = EINVAL; /* No password given. */
goto error;
} else {
size_t buflen, ulen, plen;
ulen = strlen(so->opts.socks_user);
plen = strlen(so->opts.socks_password);
if (!ulen || ulen > 255 || !plen || plen > 255) {
error = EINVAL; /* Credentials too long or too short. */
goto error;
}
buffer = dns_so_tcp_send_buffer(so, 3 + ulen + plen);
buffer[0] = 1; /* VER of the sub-negotiation. */
buffer[1] = (unsigned char) ulen;
buflen = 2;
memcpy (buffer+buflen, so->opts.socks_user, ulen);
buflen += ulen;
buffer[buflen++] = (unsigned char) plen;
memcpy (buffer+buflen, so->opts.socks_password, plen);
}
so->state++;
} /* FALL THROUGH */
case DNS_SO_SOCKS_AUTH_SEND:
if ((error = dns_so_tcp_send(so)))
goto error;
/* Skip the two length octets, and receive two octets. */
dns_so_tcp_recv_expect(so, 2);
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_AUTH_RECV:
if ((error = dns_so_tcp_recv(so)))
goto error;
buffer = dns_so_tcp_recv_buffer(so);
if (buffer[0] != 1) {
/* SOCKS server returned wrong version. */
error = EPROTO;
goto error;
}
if (buffer[1]) {
/* SOCKS server denied access. */
error = EACCES;
goto error;
}
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_REQUEST_PREPARE:
/* Send request details (rfc-1928, 4). */
buffer = dns_so_tcp_send_buffer(so, so->remote.ss_family == AF_INET6 ? 22 : 10);
buffer[0] = 5; /* VER */
buffer[1] = 1; /* CMD = CONNECT */
buffer[2] = 0; /* RSV */
if (so->remote.ss_family == AF_INET6) {
struct sockaddr_in6 *addr_in6 = (struct sockaddr_in6 *)&so->remote;
buffer[3] = 4; /* ATYP = IPv6 */
memcpy (buffer+ 4, &addr_in6->sin6_addr.s6_addr, 16); /* DST.ADDR */
memcpy (buffer+20, &addr_in6->sin6_port, 2); /* DST.PORT */
} else {
struct sockaddr_in *addr_in = (struct sockaddr_in *)&so->remote;
buffer[3] = 1; /* ATYP = IPv4 */
memcpy (buffer+4, &addr_in->sin_addr.s_addr, 4); /* DST.ADDR */
memcpy (buffer+8, &addr_in->sin_port, 2); /* DST.PORT */
}
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_REQUEST_SEND:
if ((error = dns_so_tcp_send(so)))
goto error;
/* Expect ten octets. This is the length of the
* response assuming a IPv4 address is used. */
dns_so_tcp_recv_expect(so, 10);
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_REQUEST_RECV:
if ((error = dns_so_tcp_recv(so)))
goto error;
buffer = dns_so_tcp_recv_buffer(so);
if (buffer[0] != 5 || buffer[2] != 0) {
/* Socks server returned wrong version or the
reserved field is not zero. */
error = EPROTO;
goto error;
}
if (buffer[1]) {
switch (buffer[1]) {
case 0x01: /* general SOCKS server failure. */
error = ENETDOWN;
break;
case 0x02: /* connection not allowed by ruleset. */
error = EACCES;
break;
case 0x03: /* Network unreachable */
error = ENETUNREACH;
break;
case 0x04: /* Host unreachable */
error = EHOSTUNREACH;
break;
case 0x05: /* Connection refused */
error = ECONNREFUSED;
break;
case 0x06: /* TTL expired */
error = ETIMEDOUT;
break;
case 0x08: /* Address type not supported */
error = EPROTONOSUPPORT;
break;
case 0x07: /* Command not supported */
default:
error = ENOTSUP; /* Fixme: Is there a better error? */
break;
}
goto error;
}
if (buffer[3] == 1) {
/* This was indeed an IPv4 address. */
so->state = DNS_SO_SOCKS_HANDSHAKE_DONE;
goto retry;
}
if (buffer[3] != 4) {
error = ENOTSUP;
goto error;
}
/* Expect receive twelve octets. This accounts for
* the remaining bytes assuming an IPv6 address is
* used. */
dns_so_tcp_recv_expect(so, 12);
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_REQUEST_RECV_V6:
if ((error = dns_so_tcp_recv(so)))
goto error;
so->state++; /* FALL THROUGH */
case DNS_SO_SOCKS_HANDSHAKE_DONE:
/* We have not way to store the actual address used by
* the server. Then again, we don't really care. */
/* Restore the query. */
dns_p_movptr(&so->query, &so->query_backup);
/* Reset cursors. */
so->qout = 0;
so->apos = 0;
so->alen = 0;
/* SOCKS handshake is done. Proceed with the
* lookup. */
so->state = DNS_SO_TCP_SEND;
goto retry;
default:
error = DNS_EUNKNOWN;
goto error;
} /* switch() */
trash:
DNS_CARP("discarding packet");
goto retry;
error:
switch (error) {
case DNS_EINTR:
goto retry;
case DNS_EINPROGRESS:
/* FALL THROUGH */
case DNS_EALREADY:
/* FALL THROUGH */
#if DNS_EWOULDBLOCK != DNS_EAGAIN
case DNS_EWOULDBLOCK:
/* FALL THROUGH */
#endif
error = DNS_EAGAIN;
break;
} /* switch() */
return error;
} /* dns_so_check() */
struct dns_packet *dns_so_fetch(struct dns_socket *so, int *error) {
struct dns_packet *answer;
switch (so->state) {
case DNS_SO_UDP_DONE:
case DNS_SO_TCP_DONE:
answer = so->answer;
so->answer = 0;
dns_trace_so_fetch(so->trace, answer, 0);
return answer;
default:
*error = DNS_EUNKNOWN;
dns_trace_so_fetch(so->trace, NULL, *error);
return 0;
}
} /* dns_so_fetch() */
struct dns_packet *dns_so_query(struct dns_socket *so, struct dns_packet *Q, struct sockaddr *host, int *error_) {
struct dns_packet *A;
int error;
if (!so->state) {
if ((error = dns_so_submit(so, Q, host)))
goto error;
}
if ((error = dns_so_check(so)))
goto error;
if (!(A = dns_so_fetch(so, &error)))
goto error;
dns_so_reset(so);
return A;
error:
*error_ = error;
return 0;
} /* dns_so_query() */
time_t dns_so_elapsed(struct dns_socket *so) {
return dns_elapsed(&so->elapsed);
} /* dns_so_elapsed() */
void dns_so_clear(struct dns_socket *so) {
dns_so_closefds(so, DNS_SO_CLOSE_OLD);
} /* dns_so_clear() */
static int dns_so_events2(struct dns_socket *so, enum dns_events type) {
int events = 0;
switch (so->state) {
case DNS_SO_UDP_CONN:
case DNS_SO_UDP_SEND:
events |= DNS_POLLOUT;
break;
case DNS_SO_UDP_RECV:
events |= DNS_POLLIN;
break;
case DNS_SO_TCP_CONN:
case DNS_SO_TCP_SEND:
events |= DNS_POLLOUT;
break;
case DNS_SO_TCP_RECV:
events |= DNS_POLLIN;
break;
} /* switch() */
switch (type) {
case DNS_LIBEVENT:
return DNS_POLL2EV(events);
default:
return events;
} /* switch() */
} /* dns_so_events2() */
int dns_so_events(struct dns_socket *so) {
return dns_so_events2(so, so->opts.events);
} /* dns_so_events() */
int dns_so_pollfd(struct dns_socket *so) {
switch (so->state) {
case DNS_SO_UDP_CONN:
case DNS_SO_UDP_SEND:
case DNS_SO_UDP_RECV:
return so->udp;
case DNS_SO_TCP_CONN:
case DNS_SO_TCP_SEND:
case DNS_SO_TCP_RECV:
return so->tcp;
} /* switch() */
return -1;
} /* dns_so_pollfd() */
int dns_so_poll(struct dns_socket *so, int timeout) {
return dns_poll(dns_so_pollfd(so), dns_so_events2(so, DNS_SYSPOLL), timeout);
} /* dns_so_poll() */
const struct dns_stat *dns_so_stat(struct dns_socket *so) {
return &so->stat;
} /* dns_so_stat() */
struct dns_trace *dns_so_trace(struct dns_socket *so) {
return so->trace;
} /* dns_so_trace() */
void dns_so_settrace(struct dns_socket *so, struct dns_trace *trace) {
struct dns_trace *otrace = so->trace;
so->trace = dns_trace_acquire_p(trace);
dns_trace_close(otrace);
} /* dns_so_settrace() */
/*
* R E S O L V E R R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
enum dns_res_state {
DNS_R_INIT,
DNS_R_GLUE,
DNS_R_SWITCH, /* (B)IND, (F)ILE, (C)ACHE */
DNS_R_FILE, /* Lookup in local hosts database */
DNS_R_CACHE, /* Lookup in application cache */
DNS_R_SUBMIT,
DNS_R_CHECK,
DNS_R_FETCH,
DNS_R_BIND, /* Lookup in the network */
DNS_R_SEARCH,
DNS_R_HINTS,
DNS_R_ITERATE,
DNS_R_FOREACH_NS,
DNS_R_RESOLV0_NS, /* Prologue: Setup next frame and recurse */
DNS_R_RESOLV1_NS, /* Epilog: Inspect answer */
DNS_R_FOREACH_A,
DNS_R_QUERY_A,
DNS_R_FOREACH_AAAA,
DNS_R_QUERY_AAAA,
DNS_R_CNAME0_A,
DNS_R_CNAME1_A,
DNS_R_FINISH,
DNS_R_SMART0_A,
DNS_R_SMART1_A,
DNS_R_DONE,
DNS_R_SERVFAIL,
}; /* enum dns_res_state */
#define DNS_R_MAXDEPTH 8
#define DNS_R_ENDFRAME (DNS_R_MAXDEPTH - 1)
struct dns_resolver {
struct dns_socket so;
struct dns_resolv_conf *resconf;
struct dns_hosts *hosts;
struct dns_hints *hints;
struct dns_cache *cache;
struct dns_trace *trace;
dns_atomic_t refcount;
/* Reset zeroes everything below here. */
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
enum dns_type qtype;
enum dns_class qclass;
struct dns_clock elapsed;
dns_resconf_i_t search;
struct dns_rr_i smart;
struct dns_packet *nodata; /* answer if nothing better */
unsigned sp;
struct dns_res_frame {
enum dns_res_state state;
int error;
int which; /* (B)IND, (F)ILE; index into resconf->lookup */
int qflags;
unsigned attempts;
struct dns_packet *query, *answer, *hints;
struct dns_rr_i hints_i, hints_j;
struct dns_rr hints_ns, ans_cname;
} stack[DNS_R_MAXDEPTH];
}; /* struct dns_resolver */
static int dns_res_tcp2type(int tcp) {
switch (tcp) {
case DNS_RESCONF_TCP_ONLY:
case DNS_RESCONF_TCP_SOCKS:
return SOCK_STREAM;
case DNS_RESCONF_TCP_DISABLE:
return SOCK_DGRAM;
default:
return 0;
}
} /* dns_res_tcp2type() */
struct dns_resolver *dns_res_open(struct dns_resolv_conf *resconf, struct dns_hosts *hosts, struct dns_hints *hints, struct dns_cache *cache, const struct dns_options *opts, int *_error) {
static const struct dns_resolver R_initializer
= { .refcount = 1, };
struct dns_resolver *R = 0;
int type, error;
/*
* Grab ref count early because the caller may have passed us a mortal
* reference, and we want to do the right thing if we return early
* from an error.
*/
if (resconf)
dns_resconf_acquire(resconf);
if (hosts)
dns_hosts_acquire(hosts);
if (hints)
dns_hints_acquire(hints);
if (cache)
dns_cache_acquire(cache);
/*
* Don't try to load it ourselves because a NULL object might be an
* error from, say, dns_resconf_root(), and loading
* dns_resconf_local() by default would create undesirable surpises.
*/
if (!resconf || !hosts || !hints) {
if (!*_error)
*_error = EINVAL;
goto _error;
}
if (!(R = malloc(sizeof *R)))
goto syerr;
*R = R_initializer;
type = dns_res_tcp2type(resconf->options.tcp);
if (!dns_so_init(&R->so, (struct sockaddr *)&resconf->iface, type, opts, &error))
goto error;
R->resconf = resconf;
R->hosts = hosts;
R->hints = hints;
R->cache = cache;
return R;
syerr:
error = dns_syerr();
error:
*_error = error;
_error:
dns_res_close(R);
dns_resconf_close(resconf);
dns_hosts_close(hosts);
dns_hints_close(hints);
dns_cache_close(cache);
return 0;
} /* dns_res_open() */
struct dns_resolver *dns_res_stub(const struct dns_options *opts, int *error) {
struct dns_resolv_conf *resconf = 0;
struct dns_hosts *hosts = 0;
struct dns_hints *hints = 0;
struct dns_resolver *res = 0;
if (!(resconf = dns_resconf_local(error)))
goto epilog;
if (!(hosts = dns_hosts_local(error)))
goto epilog;
if (!(hints = dns_hints_local(resconf, error)))
goto epilog;
if (!(res = dns_res_open(resconf, hosts, hints, NULL, opts, error)))
goto epilog;
epilog:
dns_resconf_close(resconf);
dns_hosts_close(hosts);
dns_hints_close(hints);
return res;
} /* dns_res_stub() */
static void dns_res_frame_destroy(struct dns_resolver *R, struct dns_res_frame *frame) {
(void)R;
dns_p_setptr(&frame->query, NULL);
dns_p_setptr(&frame->answer, NULL);
dns_p_setptr(&frame->hints, NULL);
} /* dns_res_frame_destroy() */
static void dns_res_frame_init(struct dns_resolver *R, struct dns_res_frame *frame) {
memset(frame, '\0', sizeof *frame);
/*
* NB: Can be invoked from dns_res_open, before R->resconf has been
* initialized.
*/
if (R->resconf) {
if (!R->resconf->options.recurse)
frame->qflags |= DNS_Q_RD;
if (R->resconf->options.edns0)
frame->qflags |= DNS_Q_EDNS0;
}
} /* dns_res_frame_init() */
static void dns_res_frame_reset(struct dns_resolver *R, struct dns_res_frame *frame) {
dns_res_frame_destroy(R, frame);
dns_res_frame_init(R, frame);
} /* dns_res_frame_reset() */
static dns_error_t dns_res_frame_prepare(struct dns_resolver *R, struct dns_res_frame *F, const char *qname, enum dns_type qtype, enum dns_class qclass) {
struct dns_packet *P = NULL;
if (!(F < endof(R->stack)))
return DNS_EUNKNOWN;
dns_p_movptr(&P, &F->query);
dns_res_frame_reset(R, F);
dns_p_movptr(&F->query, &P);
return dns_q_make(&F->query, qname, qtype, qclass, F->qflags);
} /* dns_res_frame_prepare() */
void dns_res_reset(struct dns_resolver *R) {
unsigned i;
dns_so_reset(&R->so);
dns_p_setptr(&R->nodata, NULL);
for (i = 0; i < lengthof(R->stack); i++)
dns_res_frame_destroy(R, &R->stack[i]);
memset(&R->qname, '\0', sizeof *R - offsetof(struct dns_resolver, qname));
for (i = 0; i < lengthof(R->stack); i++)
dns_res_frame_init(R, &R->stack[i]);
} /* dns_res_reset() */
void dns_res_close(struct dns_resolver *R) {
if (!R || 1 < dns_res_release(R))
return;
dns_res_reset(R);
dns_so_destroy(&R->so);
dns_hints_close(R->hints);
dns_hosts_close(R->hosts);
dns_resconf_close(R->resconf);
dns_cache_close(R->cache);
dns_trace_close(R->trace);
free(R);
} /* dns_res_close() */
dns_refcount_t dns_res_acquire(struct dns_resolver *R) {
return dns_atomic_fetch_add(&R->refcount);
} /* dns_res_acquire() */
dns_refcount_t dns_res_release(struct dns_resolver *R) {
return dns_atomic_fetch_sub(&R->refcount);
} /* dns_res_release() */
struct dns_resolver *dns_res_mortal(struct dns_resolver *res) {
if (res)
dns_res_release(res);
return res;
} /* dns_res_mortal() */
static struct dns_packet *dns_res_merge(struct dns_packet *P0, struct dns_packet *P1, int *error_) {
size_t bufsiz = P0->end + P1->end;
struct dns_packet *P[3] = { P0, P1, 0 };
struct dns_rr rr[3];
int error, copy, i;
enum dns_section section;
retry:
if (!(P[2] = dns_p_make(bufsiz, &error)))
goto error;
dns_rr_foreach(&rr[0], P[0], .section = DNS_S_QD) {
if ((error = dns_rr_copy(P[2], &rr[0], P[0])))
goto error;
}
for (section = DNS_S_AN; (DNS_S_ALL & section); section <<= 1) {
for (i = 0; i < 2; i++) {
dns_rr_foreach(&rr[i], P[i], .section = section) {
copy = 1;
dns_rr_foreach(&rr[2], P[2], .type = rr[i].type, .section = (DNS_S_ALL & ~DNS_S_QD)) {
if (0 == dns_rr_cmp(&rr[i], P[i], &rr[2], P[2])) {
copy = 0;
break;
}
}
if (copy && (error = dns_rr_copy(P[2], &rr[i], P[i]))) {
if (error == DNS_ENOBUFS && bufsiz < 65535) {
dns_p_setptr(&P[2], NULL);
bufsiz = DNS_PP_MAX(65535, bufsiz * 2);
goto retry;
}
goto error;
}
} /* foreach(rr) */
} /* foreach(packet) */
} /* foreach(section) */
return P[2];
error:
*error_ = error;
dns_p_free(P[2]);
return 0;
} /* dns_res_merge() */
static struct dns_packet *dns_res_glue(struct dns_resolver *R, struct dns_packet *Q) {
struct dns_packet *P = dns_p_new(512);
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
enum dns_type qtype;
struct dns_rr rr;
unsigned sp;
int error;
if (!(qlen = dns_d_expand(qname, sizeof qname, 12, Q, &error))
|| qlen >= sizeof qname)
return 0;
if (!(qtype = dns_rr_type(12, Q)))
return 0;
if ((error = dns_p_push(P, DNS_S_QD, qname, strlen(qname), qtype, DNS_C_IN, 0, 0)))
return 0;
for (sp = 0; sp <= R->sp; sp++) {
if (!R->stack[sp].answer)
continue;
dns_rr_foreach(&rr, R->stack[sp].answer, .name = qname, .type = qtype, .section = (DNS_S_ALL & ~DNS_S_QD)) {
rr.section = DNS_S_AN;
if ((error = dns_rr_copy(P, &rr, R->stack[sp].answer)))
return 0;
}
}
if (dns_p_count(P, DNS_S_AN) > 0)
goto copy;
/* Otherwise, look for a CNAME */
for (sp = 0; sp <= R->sp; sp++) {
if (!R->stack[sp].answer)
continue;
dns_rr_foreach(&rr, R->stack[sp].answer, .name = qname, .type = DNS_T_CNAME, .section = (DNS_S_ALL & ~DNS_S_QD)) {
rr.section = DNS_S_AN;
if ((error = dns_rr_copy(P, &rr, R->stack[sp].answer)))
return 0;
}
}
if (!dns_p_count(P, DNS_S_AN))
return 0;
copy:
return dns_p_copy(dns_p_make(P->end, &error), P);
} /* dns_res_glue() */
/*
* Sort NS records by three criteria:
*
* 1) Whether glue is present.
* 2) Whether glue record is original or of recursive lookup.
* 3) Randomly shuffle records which share the above criteria.
*
* NOTE: Assumes only NS records passed, AND ASSUMES no new NS records will
* be added during an iteration.
*
* FIXME: Only groks A glue, not AAAA glue.
*/
static int dns_res_nameserv_cmp(struct dns_rr *a, struct dns_rr *b, struct dns_rr_i *i, struct dns_packet *P) {
_Bool glued[2] = { 0 };
struct dns_rr x = { 0 }, y = { 0 };
struct dns_ns ns;
int cmp, error;
if (!(error = dns_ns_parse(&ns, a, P)))
glued[0] = !!dns_rr_grep(&x, 1, dns_rr_i_new(P, .section = (DNS_S_ALL & ~DNS_S_QD), .name = ns.host, .type = DNS_T_A), P, &error);
if (!(error = dns_ns_parse(&ns, b, P)))
glued[1] = !!dns_rr_grep(&y, 1, dns_rr_i_new(P, .section = (DNS_S_ALL & ~DNS_S_QD), .name = ns.host, .type = DNS_T_A), P, &error);
if ((cmp = glued[1] - glued[0])) {
return cmp;
} else if ((cmp = (dns_rr_offset(&y) < i->args[0]) - (dns_rr_offset(&x) < i->args[0]))) {
return cmp;
} else {
return dns_rr_i_shuffle(a, b, i, P);
}
} /* dns_res_nameserv_cmp() */
#define dgoto(sp, i) \
do { R->stack[(sp)].state = (i); goto exec; } while (0)
static int dns_res_exec(struct dns_resolver *R) {
struct dns_res_frame *F;
struct dns_packet *P;
union {
char host[DNS_D_MAXNAME + 1];
char name[DNS_D_MAXNAME + 1];
struct dns_ns ns;
struct dns_cname cname;
} u;
size_t len;
struct dns_rr rr;
int error;
exec:
F = &R->stack[R->sp];
switch (F->state) {
case DNS_R_INIT:
F->state++; /* FALL THROUGH */
case DNS_R_GLUE:
if (R->sp == 0)
dgoto(R->sp, DNS_R_SWITCH);
if (!F->query)
goto noquery;
if (!(F->answer = dns_res_glue(R, F->query)))
dgoto(R->sp, DNS_R_SWITCH);
if (!(len = dns_d_expand(u.name, sizeof u.name, 12, F->query, &error)))
goto error;
else if (len >= sizeof u.name)
goto toolong;
dns_rr_foreach(&rr, F->answer, .name = u.name, .type = dns_rr_type(12, F->query), .section = DNS_S_AN) {
dgoto(R->sp, DNS_R_FINISH);
}
dns_rr_foreach(&rr, F->answer, .name = u.name, .type = DNS_T_CNAME, .section = DNS_S_AN) {
F->ans_cname = rr;
dgoto(R->sp, DNS_R_CNAME0_A);
}
F->state++;
case DNS_R_SWITCH:
while (F->which < (int)sizeof R->resconf->lookup && R->resconf->lookup[F->which]) {
switch (R->resconf->lookup[F->which++]) {
case 'b': case 'B':
dgoto(R->sp, DNS_R_BIND);
case 'f': case 'F':
dgoto(R->sp, DNS_R_FILE);
case 'c': case 'C':
if (R->cache)
dgoto(R->sp, DNS_R_CACHE);
break;
default:
break;
}
}
/*
* FIXME: Examine more closely whether our logic is correct
* and DNS_R_SERVFAIL is the correct default response.
*
* Case 1: We got here because we never got an answer on the
* wire. All queries timed-out and we reached maximum
* attempts count. See DNS_R_FOREACH_NS. In that case
* DNS_R_SERVFAIL is the correct state, unless we want to
* return DNS_ETIMEDOUT.
*
* Case 2: We were a stub resolver and got an unsatisfactory
* answer (empty ANSWER section) which caused us to jump
* back to DNS_R_SEARCH and ultimately to DNS_R_SWITCH. We
* return the answer returned from the wire, which we
* stashed in R->nodata.
*
* Case 3: We reached maximum attempts count as in case #1,
* but never got an authoritative response which caused us
* to short-circuit. See end of DNS_R_QUERY_A case. We
* should probably prepare R->nodata as in case #2.
*/
if (R->sp == 0 && R->nodata) { /* XXX: can we just return nodata regardless? */
dns_p_movptr(&F->answer, &R->nodata);
dgoto(R->sp, DNS_R_FINISH);
}
dgoto(R->sp, DNS_R_SERVFAIL);
case DNS_R_FILE:
if (R->sp > 0) {
if (!dns_p_setptr(&F->answer, dns_hosts_query(R->hosts, F->query, &error)))
goto error;
if (dns_p_count(F->answer, DNS_S_AN) > 0)
dgoto(R->sp, DNS_R_FINISH);
dns_p_setptr(&F->answer, NULL);
} else {
R->search = 0;
while ((len = dns_resconf_search(u.name, sizeof u.name, R->qname, R->qlen, R->resconf, &R->search))) {
if ((error = dns_q_make2(&F->query, u.name, len, R->qtype, R->qclass, F->qflags)))
goto error;
if (!dns_p_setptr(&F->answer, dns_hosts_query(R->hosts, F->query, &error)))
goto error;
if (dns_p_count(F->answer, DNS_S_AN) > 0)
dgoto(R->sp, DNS_R_FINISH);
dns_p_setptr(&F->answer, NULL);
}
}
dgoto(R->sp, DNS_R_SWITCH);
case DNS_R_CACHE:
error = 0;
if (!F->query && (error = dns_q_make(&F->query, R->qname, R->qtype, R->qclass, F->qflags)))
goto error;
if (dns_p_setptr(&F->answer, R->cache->query(F->query, R->cache, &error))) {
if (dns_p_count(F->answer, DNS_S_AN) > 0)
dgoto(R->sp, DNS_R_FINISH);
dns_p_setptr(&F->answer, NULL);
dgoto(R->sp, DNS_R_SWITCH);
} else if (error)
goto error;
F->state++; /* FALL THROUGH */
case DNS_R_SUBMIT:
if ((error = R->cache->submit(F->query, R->cache)))
goto error;
F->state++; /* FALL THROUGH */
case DNS_R_CHECK:
if ((error = R->cache->check(R->cache)))
goto error;
F->state++; /* FALL THROUGH */
case DNS_R_FETCH:
error = 0;
if (dns_p_setptr(&F->answer, R->cache->fetch(R->cache, &error))) {
if (dns_p_count(F->answer, DNS_S_AN) > 0)
dgoto(R->sp, DNS_R_FINISH);
dns_p_setptr(&F->answer, NULL);
dgoto(R->sp, DNS_R_SWITCH);
} else if (error)
goto error;
dgoto(R->sp, DNS_R_SWITCH);
case DNS_R_BIND:
if (R->sp > 0) {
if (!F->query)
goto noquery;
dgoto(R->sp, DNS_R_HINTS);
}
R->search = 0;
F->state++; /* FALL THROUGH */
case DNS_R_SEARCH:
/*
* XXX: We probably should only apply the domain search
* algorithm if R->sp == 0.
*/
if (!(len = dns_resconf_search(u.name, sizeof u.name, R->qname, R->qlen, R->resconf, &R->search)))
dgoto(R->sp, DNS_R_SWITCH);
if ((error = dns_q_make2(&F->query, u.name, len, R->qtype, R->qclass, F->qflags)))
goto error;
F->state++; /* FALL THROUGH */
case DNS_R_HINTS:
if (!dns_p_setptr(&F->hints, dns_hints_query(R->hints, F->query, &error)))
goto error;
F->state++; /* FALL THROUGH */
case DNS_R_ITERATE:
dns_rr_i_init(&F->hints_i, F->hints);
F->hints_i.section = DNS_S_AUTHORITY;
F->hints_i.type = DNS_T_NS;
F->hints_i.sort = &dns_res_nameserv_cmp;
F->hints_i.args[0] = F->hints->end;
F->state++; /* FALL THROUGH */
case DNS_R_FOREACH_NS:
dns_rr_i_save(&F->hints_i);
/* Load our next nameserver host. */
if (!dns_rr_grep(&F->hints_ns, 1, &F->hints_i, F->hints, &error)) {
if (++F->attempts < R->resconf->options.attempts)
dgoto(R->sp, DNS_R_ITERATE);
dgoto(R->sp, DNS_R_SWITCH);
}
dns_rr_i_init(&F->hints_j, F->hints);
/* Assume there are glue records */
dgoto(R->sp, DNS_R_FOREACH_A);
case DNS_R_RESOLV0_NS:
/* Have we reached our max depth? */
if (&F[1] >= endof(R->stack))
dgoto(R->sp, DNS_R_FOREACH_NS);
if ((error = dns_ns_parse(&u.ns, &F->hints_ns, F->hints)))
goto error;
if ((error = dns_res_frame_prepare(R, &F[1], u.ns.host, DNS_T_A, DNS_C_IN)))
goto error;
F->state++;
dgoto(++R->sp, DNS_R_INIT);
case DNS_R_RESOLV1_NS:
if (!(len = dns_d_expand(u.host, sizeof u.host, 12, F[1].query, &error)))
goto error;
else if (len >= sizeof u.host)
goto toolong;
dns_rr_foreach(&rr, F[1].answer, .name = u.host, .type = DNS_T_A, .section = (DNS_S_ALL & ~DNS_S_QD)) {
rr.section = DNS_S_AR;
if ((error = dns_rr_copy(F->hints, &rr, F[1].answer)))
goto error;
dns_rr_i_rewind(&F->hints_i); /* Now there's glue. */
}
dgoto(R->sp, DNS_R_FOREACH_NS);
case DNS_R_FOREACH_A: {
struct dns_a a;
struct sockaddr_in sin;
/*
* NOTE: Iterator initialized in DNS_R_FOREACH_NS because
* this state is re-entrant, but we need to reset
* .name to a valid pointer each time.
*/
if ((error = dns_ns_parse(&u.ns, &F->hints_ns, F->hints)))
goto error;
F->hints_j.name = u.ns.host;
F->hints_j.type = DNS_T_A;
F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
if (!dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
if (!dns_rr_i_count(&F->hints_j)) {
/* Check if we have in fact servers
with an IPv6 address. */
dns_rr_i_init(&F->hints_j, F->hints);
F->hints_j.name = u.ns.host;
F->hints_j.type = DNS_T_AAAA;
F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
if (dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
/* We do. Reinitialize
iterator and handle it. */
dns_rr_i_init(&F->hints_j, F->hints);
dgoto(R->sp, DNS_R_FOREACH_AAAA);
}
dgoto(R->sp, DNS_R_RESOLV0_NS);
}
dgoto(R->sp, DNS_R_FOREACH_NS);
}
if ((error = dns_a_parse(&a, &rr, F->hints)))
goto error;
memset(&sin, '\0', sizeof sin); /* NB: silence valgrind */
sin.sin_family = AF_INET;
sin.sin_addr = a.addr;
if (R->sp == 0)
sin.sin_port = dns_hints_port(R->hints, AF_INET, &sin.sin_addr);
else
sin.sin_port = htons(53);
if (DNS_DEBUG) {
char addr[INET_ADDRSTRLEN + 1];
dns_a_print(addr, sizeof addr, &a);
dns_header(F->query)->qid = dns_so_mkqid(&R->so);
DNS_SHOW(F->query, "ASKING: %s/%s @ DEPTH: %u)", u.ns.host, addr, R->sp);
}
dns_trace_setcname(R->trace, u.ns.host, (struct sockaddr *)&sin);
if ((error = dns_so_submit(&R->so, F->query, (struct sockaddr *)&sin)))
goto error;
F->state++;
} /* FALL THROUGH */
case DNS_R_QUERY_A:
if (dns_so_elapsed(&R->so) >= dns_resconf_timeout(R->resconf))
dgoto(R->sp, DNS_R_FOREACH_A);
error = dns_so_check(&R->so);
if (error == ECONNREFUSED)
dgoto(R->sp, DNS_R_FOREACH_A);
else if (error)
goto error;
if (!dns_p_setptr(&F->answer, dns_so_fetch(&R->so, &error)))
goto error;
if (DNS_DEBUG) {
DNS_SHOW(F->answer, "ANSWER @ DEPTH: %u)", R->sp);
}
if (dns_p_rcode(F->answer) == DNS_RC_FORMERR ||
dns_p_rcode(F->answer) == DNS_RC_NOTIMP ||
dns_p_rcode(F->answer) == DNS_RC_BADVERS) {
/* Temporarily disable EDNS0 and try again. */
if (F->qflags & DNS_Q_EDNS0) {
F->qflags &= ~DNS_Q_EDNS0;
if ((error = dns_q_remake(&F->query, F->qflags)))
goto error;
dgoto(R->sp, DNS_R_FOREACH_A);
}
}
if ((error = dns_rr_parse(&rr, 12, F->query)))
goto error;
if (!(len = dns_d_expand(u.name, sizeof u.name, rr.dn.p, F->query, &error)))
goto error;
else if (len >= sizeof u.name)
goto toolong;
dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = rr.type) {
dgoto(R->sp, DNS_R_FINISH); /* Found */
}
dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = DNS_T_CNAME) {
F->ans_cname = rr;
dgoto(R->sp, DNS_R_CNAME0_A);
}
/*
* XXX: The condition here should probably check whether
* R->sp == 0, because DNS_R_SEARCH runs regardless of
* options.recurse. See DNS_R_BIND.
*/
if (!R->resconf->options.recurse) {
/* Make first answer our tentative answer */
if (!R->nodata)
dns_p_movptr(&R->nodata, &F->answer);
dgoto(R->sp, DNS_R_SEARCH);
}
dns_rr_foreach(&rr, F->answer, .section = DNS_S_NS, .type = DNS_T_NS) {
dns_p_movptr(&F->hints, &F->answer);
dgoto(R->sp, DNS_R_ITERATE);
}
/* XXX: Should this go further up? */
if (dns_header(F->answer)->aa)
dgoto(R->sp, DNS_R_FINISH);
/* XXX: Should we copy F->answer to R->nodata? */
dgoto(R->sp, DNS_R_FOREACH_A);
case DNS_R_FOREACH_AAAA: {
struct dns_aaaa aaaa;
struct sockaddr_in6 sin6;
/*
* NOTE: Iterator initialized in DNS_R_FOREACH_NS because
* this state is re-entrant, but we need to reset
* .name to a valid pointer each time.
*/
if ((error = dns_ns_parse(&u.ns, &F->hints_ns, F->hints)))
goto error;
F->hints_j.name = u.ns.host;
F->hints_j.type = DNS_T_AAAA;
F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
if (!dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
if (!dns_rr_i_count(&F->hints_j)) {
/* Check if we have in fact servers
with an IPv4 address. */
dns_rr_i_init(&F->hints_j, F->hints);
F->hints_j.name = u.ns.host;
F->hints_j.type = DNS_T_A;
F->hints_j.section = DNS_S_ALL & ~DNS_S_QD;
if (dns_rr_grep(&rr, 1, &F->hints_j, F->hints, &error)) {
/* We do. Reinitialize
iterator and handle it. */
dns_rr_i_init(&F->hints_j, F->hints);
dgoto(R->sp, DNS_R_FOREACH_A);
}
dgoto(R->sp, DNS_R_RESOLV0_NS);
}
dgoto(R->sp, DNS_R_FOREACH_NS);
}
if ((error = dns_aaaa_parse(&aaaa, &rr, F->hints)))
goto error;
memset(&sin6, '\0', sizeof sin6); /* NB: silence valgrind */
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = aaaa.addr;
if (R->sp == 0)
sin6.sin6_port = dns_hints_port(R->hints, AF_INET, &sin6.sin6_addr);
else
sin6.sin6_port = htons(53);
if (DNS_DEBUG) {
char addr[INET6_ADDRSTRLEN + 1];
dns_aaaa_print(addr, sizeof addr, &aaaa);
dns_header(F->query)->qid = dns_so_mkqid(&R->so);
DNS_SHOW(F->query, "ASKING: %s/%s @ DEPTH: %u)", u.ns.host, addr, R->sp);
}
dns_trace_setcname(R->trace, u.ns.host, (struct sockaddr *)&sin6);
if ((error = dns_so_submit(&R->so, F->query, (struct sockaddr *)&sin6)))
goto error;
F->state++;
} /* FALL THROUGH */
case DNS_R_QUERY_AAAA:
if (dns_so_elapsed(&R->so) >= dns_resconf_timeout(R->resconf))
dgoto(R->sp, DNS_R_FOREACH_AAAA);
error = dns_so_check(&R->so);
if (error == ECONNREFUSED)
dgoto(R->sp, DNS_R_FOREACH_AAAA);
else if (error)
goto error;
if (!dns_p_setptr(&F->answer, dns_so_fetch(&R->so, &error)))
goto error;
if (DNS_DEBUG) {
DNS_SHOW(F->answer, "ANSWER @ DEPTH: %u)", R->sp);
}
if (dns_p_rcode(F->answer) == DNS_RC_FORMERR ||
dns_p_rcode(F->answer) == DNS_RC_NOTIMP ||
dns_p_rcode(F->answer) == DNS_RC_BADVERS) {
/* Temporarily disable EDNS0 and try again. */
if (F->qflags & DNS_Q_EDNS0) {
F->qflags &= ~DNS_Q_EDNS0;
if ((error = dns_q_remake(&F->query, F->qflags)))
goto error;
dgoto(R->sp, DNS_R_FOREACH_AAAA);
}
}
if ((error = dns_rr_parse(&rr, 12, F->query)))
goto error;
if (!(len = dns_d_expand(u.name, sizeof u.name, rr.dn.p, F->query, &error)))
goto error;
else if (len >= sizeof u.name)
goto toolong;
dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = rr.type) {
dgoto(R->sp, DNS_R_FINISH); /* Found */
}
dns_rr_foreach(&rr, F->answer, .section = DNS_S_AN, .name = u.name, .type = DNS_T_CNAME) {
F->ans_cname = rr;
dgoto(R->sp, DNS_R_CNAME0_A);
}
/*
* XXX: The condition here should probably check whether
* R->sp == 0, because DNS_R_SEARCH runs regardless of
* options.recurse. See DNS_R_BIND.
*/
if (!R->resconf->options.recurse) {
/* Make first answer our tentative answer */
if (!R->nodata)
dns_p_movptr(&R->nodata, &F->answer);
dgoto(R->sp, DNS_R_SEARCH);
}
dns_rr_foreach(&rr, F->answer, .section = DNS_S_NS, .type = DNS_T_NS) {
dns_p_movptr(&F->hints, &F->answer);
dgoto(R->sp, DNS_R_ITERATE);
}
/* XXX: Should this go further up? */
if (dns_header(F->answer)->aa)
dgoto(R->sp, DNS_R_FINISH);
/* XXX: Should we copy F->answer to R->nodata? */
dgoto(R->sp, DNS_R_FOREACH_AAAA);
case DNS_R_CNAME0_A:
if (&F[1] >= endof(R->stack))
dgoto(R->sp, DNS_R_FINISH);
if ((error = dns_cname_parse(&u.cname, &F->ans_cname, F->answer)))
goto error;
if ((error = dns_res_frame_prepare(R, &F[1], u.cname.host, dns_rr_type(12, F->query), DNS_C_IN)))
goto error;
F->state++;
dgoto(++R->sp, DNS_R_INIT);
case DNS_R_CNAME1_A:
if (!(P = dns_res_merge(F->answer, F[1].answer, &error)))
goto error;
dns_p_setptr(&F->answer, P);
dgoto(R->sp, DNS_R_FINISH);
case DNS_R_FINISH:
if (!F->answer)
goto noanswer;
if (!R->resconf->options.smart || R->sp > 0)
dgoto(R->sp, DNS_R_DONE);
R->smart.section = DNS_S_AN;
R->smart.type = R->qtype;
dns_rr_i_init(&R->smart, F->answer);
F->state++; /* FALL THROUGH */
case DNS_R_SMART0_A:
if (&F[1] >= endof(R->stack))
dgoto(R->sp, DNS_R_DONE);
while (dns_rr_grep(&rr, 1, &R->smart, F->answer, &error)) {
union {
struct dns_ns ns;
struct dns_mx mx;
struct dns_srv srv;
} rd;
const char *qname;
enum dns_type qtype;
enum dns_class qclass;
switch (rr.type) {
case DNS_T_NS:
if ((error = dns_ns_parse(&rd.ns, &rr, F->answer)))
goto error;
qname = rd.ns.host;
qtype = DNS_T_A;
qclass = DNS_C_IN;
break;
case DNS_T_MX:
if ((error = dns_mx_parse(&rd.mx, &rr, F->answer)))
goto error;
qname = rd.mx.host;
qtype = DNS_T_A;
qclass = DNS_C_IN;
break;
case DNS_T_SRV:
if ((error = dns_srv_parse(&rd.srv, &rr, F->answer)))
goto error;
qname = rd.srv.target;
qtype = DNS_T_A;
qclass = DNS_C_IN;
break;
default:
continue;
} /* switch() */
if ((error = dns_res_frame_prepare(R, &F[1], qname, qtype, qclass)))
goto error;
F->state++;
dgoto(++R->sp, DNS_R_INIT);
} /* while() */
/*
* NOTE: SMTP specification says to fallback to A record.
*
* XXX: Should we add a mock MX answer?
*/
if (R->qtype == DNS_T_MX && R->smart.state.count == 0) {
if ((error = dns_res_frame_prepare(R, &F[1], R->qname, DNS_T_A, DNS_C_IN)))
goto error;
R->smart.state.count++;
F->state++;
dgoto(++R->sp, DNS_R_INIT);
}
dgoto(R->sp, DNS_R_DONE);
case DNS_R_SMART1_A:
if (!F[1].answer)
goto noanswer;
/*
* FIXME: For CNAME chains (which are typically illegal in
* this context), we should rewrite the record host name
* to the original smart qname. All the user cares about
* is locating that A/AAAA record.
*/
dns_rr_foreach(&rr, F[1].answer, .section = DNS_S_AN, .type = DNS_T_A) {
rr.section = DNS_S_AR;
if (dns_rr_exists(&rr, F[1].answer, F->answer))
continue;
while ((error = dns_rr_copy(F->answer, &rr, F[1].answer))) {
if (error != DNS_ENOBUFS)
goto error;
if ((error = dns_p_grow(&F->answer)))
goto error;
}
}
dgoto(R->sp, DNS_R_SMART0_A);
case DNS_R_DONE:
if (!F->answer)
goto noanswer;
if (R->sp > 0)
dgoto(--R->sp, F[-1].state);
break;
case DNS_R_SERVFAIL:
if (!dns_p_setptr(&F->answer, dns_p_make(DNS_P_QBUFSIZ, &error)))
goto error;
dns_header(F->answer)->qr = 1;
dns_header(F->answer)->rcode = DNS_RC_SERVFAIL;
if ((error = dns_p_push(F->answer, DNS_S_QD, R->qname, strlen(R->qname), R->qtype, R->qclass, 0, 0)))
goto error;
dgoto(R->sp, DNS_R_DONE);
default:
error = EINVAL;
goto error;
} /* switch () */
return 0;
noquery:
error = DNS_ENOQUERY;
goto error;
noanswer:
error = DNS_ENOANSWER;
goto error;
toolong:
error = DNS_EILLEGAL;
/* FALL THROUGH */
error:
return error;
} /* dns_res_exec() */
#undef goto
void dns_res_clear(struct dns_resolver *R) {
switch (R->stack[R->sp].state) {
case DNS_R_CHECK:
R->cache->clear(R->cache);
break;
default:
dns_so_clear(&R->so);
break;
}
} /* dns_res_clear() */
static int dns_res_events2(struct dns_resolver *R, enum dns_events type) {
int events;
switch (R->stack[R->sp].state) {
case DNS_R_CHECK:
events = R->cache->events(R->cache);
return (type == DNS_LIBEVENT)? DNS_POLL2EV(events) : events;
default:
return dns_so_events2(&R->so, type);
}
} /* dns_res_events2() */
int dns_res_events(struct dns_resolver *R) {
return dns_res_events2(R, R->so.opts.events);
} /* dns_res_events() */
int dns_res_pollfd(struct dns_resolver *R) {
switch (R->stack[R->sp].state) {
case DNS_R_CHECK:
return R->cache->pollfd(R->cache);
default:
return dns_so_pollfd(&R->so);
}
} /* dns_res_pollfd() */
time_t dns_res_timeout(struct dns_resolver *R) {
time_t elapsed;
switch (R->stack[R->sp].state) {
#if 0
case DNS_R_QUERY_AAAA:
#endif
case DNS_R_QUERY_A:
elapsed = dns_so_elapsed(&R->so);
if (elapsed <= dns_resconf_timeout(R->resconf))
return R->resconf->options.timeout - elapsed;
break;
default:
break;
} /* switch() */
/*
* NOTE: We're not in a pollable state, or the user code hasn't
* called dns_res_check properly. The calling code is probably
* broken. Put them into a slow-burn pattern.
*/
return 1;
} /* dns_res_timeout() */
time_t dns_res_elapsed(struct dns_resolver *R) {
return dns_elapsed(&R->elapsed);
} /* dns_res_elapsed() */
int dns_res_poll(struct dns_resolver *R, int timeout) {
return dns_poll(dns_res_pollfd(R), dns_res_events2(R, DNS_SYSPOLL), timeout);
} /* dns_res_poll() */
int dns_res_submit2(struct dns_resolver *R, const char *qname, size_t qlen, enum dns_type qtype, enum dns_class qclass) {
dns_res_reset(R);
/* Don't anchor; that can conflict with searchlist generation. */
dns_d_init(R->qname, sizeof R->qname, qname, (R->qlen = qlen), 0);
R->qtype = qtype;
R->qclass = qclass;
dns_begin(&R->elapsed);
dns_trace_res_submit(R->trace, R->qname, R->qtype, R->qclass, 0);
return 0;
} /* dns_res_submit2() */
int dns_res_submit(struct dns_resolver *R, const char *qname, enum dns_type qtype, enum dns_class qclass) {
return dns_res_submit2(R, qname, strlen(qname), qtype, qclass);
} /* dns_res_submit() */
int dns_res_check(struct dns_resolver *R) {
int error;
if (R->stack[0].state != DNS_R_DONE) {
if ((error = dns_res_exec(R)))
return error;
}
return 0;
} /* dns_res_check() */
struct dns_packet *dns_res_fetch(struct dns_resolver *R, int *_error) {
struct dns_packet *P = NULL;
int error;
if (R->stack[0].state != DNS_R_DONE) {
error = DNS_EUNKNOWN;
goto error;
}
if (!dns_p_movptr(&P, &R->stack[0].answer)) {
error = DNS_EFETCHED;
goto error;
}
dns_trace_res_fetch(R->trace, P, 0);
return P;
error:
*_error = error;
dns_trace_res_fetch(R->trace, NULL, error);
return NULL;
} /* dns_res_fetch() */
static struct dns_packet *dns_res_fetch_and_study(struct dns_resolver *R, int *_error) {
struct dns_packet *P = NULL;
int error;
if (!(P = dns_res_fetch(R, &error)))
goto error;
if ((error = dns_p_study(P)))
goto error;
return P;
error:
*_error = error;
dns_p_free(P);
return NULL;
} /* dns_res_fetch_and_study() */
struct dns_packet *dns_res_query(struct dns_resolver *res, const char *qname, enum dns_type qtype, enum dns_class qclass, int timeout, int *error_) {
int error;
if ((error = dns_res_submit(res, qname, qtype, qclass)))
goto error;
while ((error = dns_res_check(res))) {
if (dns_res_elapsed(res) > timeout)
error = DNS_ETIMEDOUT;
if (error != DNS_EAGAIN)
goto error;
if ((error = dns_res_poll(res, 1)))
goto error;
}
return dns_res_fetch(res, error_);
error:
*error_ = error;
return 0;
} /* dns_res_query() */
const struct dns_stat *dns_res_stat(struct dns_resolver *res) {
return dns_so_stat(&res->so);
} /* dns_res_stat() */
void dns_res_sethints(struct dns_resolver *res, struct dns_hints *hints) {
dns_hints_acquire(hints); /* acquire first in case same hints object */
dns_hints_close(res->hints);
res->hints = hints;
} /* dns_res_sethints() */
struct dns_trace *dns_res_trace(struct dns_resolver *res) {
return res->trace;
} /* dns_res_trace() */
void dns_res_settrace(struct dns_resolver *res, struct dns_trace *trace) {
struct dns_trace *otrace = res->trace;
res->trace = dns_trace_acquire_p(trace);
dns_trace_close(otrace);
dns_so_settrace(&res->so, trace);
} /* dns_res_settrace() */
/*
* A D D R I N F O R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
struct dns_addrinfo {
struct addrinfo hints;
struct dns_resolver *res;
struct dns_trace *trace;
char qname[DNS_D_MAXNAME + 1];
enum dns_type qtype;
unsigned short qport, port;
struct {
unsigned long todo;
int state;
int atype;
enum dns_type qtype;
} af;
struct dns_packet *answer;
struct dns_packet *glue;
struct dns_rr_i i, g;
struct dns_rr rr;
char cname[DNS_D_MAXNAME + 1];
char i_cname[DNS_D_MAXNAME + 1], g_cname[DNS_D_MAXNAME + 1];
int g_depth;
int state;
int found;
struct dns_stat st;
}; /* struct dns_addrinfo */
#define DNS_AI_AFMAX 32
#define DNS_AI_AF2INDEX(af) (1UL << ((af) - 1))
static inline unsigned long dns_ai_af2index(int af) {
dns_static_assert(dns_same_type(unsigned long, DNS_AI_AF2INDEX(1), 1), "internal type mismatch");
dns_static_assert(dns_same_type(unsigned long, ((struct dns_addrinfo *)0)->af.todo, 1), "internal type mismatch");
return (af > 0 && af <= DNS_AI_AFMAX)? DNS_AI_AF2INDEX(af) : 0;
}
static int dns_ai_setaf(struct dns_addrinfo *ai, int af, int qtype) {
ai->af.atype = af;
ai->af.qtype = qtype;
ai->af.todo &= ~dns_ai_af2index(af);
return af;
} /* dns_ai_setaf() */
#define DNS_SM_RESTORE \
do { pc = 0xff & (ai->af.state >> 0); i = 0xff & (ai->af.state >> 8); } while (0)
#define DNS_SM_SAVE \
do { ai->af.state = ((0xff & pc) << 0) | ((0xff & i) << 8); } while (0)
static int dns_ai_nextaf(struct dns_addrinfo *ai) {
int i, pc;
dns_static_assert(AF_UNSPEC == 0, "AF_UNSPEC constant not 0");
dns_static_assert(AF_INET <= DNS_AI_AFMAX, "AF_INET constant too large");
dns_static_assert(AF_INET6 <= DNS_AI_AFMAX, "AF_INET6 constant too large");
DNS_SM_ENTER;
if (ai->res) {
/*
* NB: On OpenBSD, at least, the types of entries resolved
* is the intersection of the /etc/resolv.conf families and
* the families permitted by the .ai_type hint. So if
* /etc/resolv.conf has "family inet4" and .ai_type
* is AF_INET6, then the address ::1 will return 0 entries
* even if AI_NUMERICHOST is specified in .ai_flags.
*/
while (i < (int)lengthof(ai->res->resconf->family)) {
int af = ai->res->resconf->family[i++];
if (af == AF_UNSPEC) {
DNS_SM_EXIT;
} else if (af < 0 || af > DNS_AI_AFMAX) {
continue;
} else if (!(DNS_AI_AF2INDEX(af) & ai->af.todo)) {
continue;
} else if (af == AF_INET) {
DNS_SM_YIELD(dns_ai_setaf(ai, AF_INET, DNS_T_A));
} else if (af == AF_INET6) {
DNS_SM_YIELD(dns_ai_setaf(ai, AF_INET6, DNS_T_AAAA));
}
}
} else {
/*
* NB: If we get here than AI_NUMERICFLAGS should be set and
* order shouldn't matter.
*/
if (DNS_AI_AF2INDEX(AF_INET) & ai->af.todo)
DNS_SM_YIELD(dns_ai_setaf(ai, AF_INET, DNS_T_A));
if (DNS_AI_AF2INDEX(AF_INET6) & ai->af.todo)
DNS_SM_YIELD(dns_ai_setaf(ai, AF_INET6, DNS_T_AAAA));
}
DNS_SM_LEAVE;
return dns_ai_setaf(ai, AF_UNSPEC, 0);
} /* dns_ai_nextaf() */
#undef DNS_SM_RESTORE
#undef DNS_SM_SAVE
static enum dns_type dns_ai_qtype(struct dns_addrinfo *ai) {
return (ai->qtype)? ai->qtype : ai->af.qtype;
} /* dns_ai_qtype() */
/* JW: This is not defined on mingw. */
#ifndef AI_NUMERICSERV
#define AI_NUMERICSERV 0
#endif
static dns_error_t dns_ai_parseport(unsigned short *port, const char *serv, const struct addrinfo *hints) {
const char *cp = serv;
unsigned long n = 0;
while (*cp >= '0' && *cp <= '9' && n < 65536) {
n *= 10;
n += *cp++ - '0';
}
if (*cp == '\0') {
if (cp == serv || n >= 65536)
return DNS_ESERVICE;
*port = n;
return 0;
}
if (hints->ai_flags & AI_NUMERICSERV)
return DNS_ESERVICE;
/* TODO: try getaddrinfo(NULL, serv, { .ai_flags = AI_NUMERICSERV }) */
return DNS_ESERVICE;
} /* dns_ai_parseport() */
struct dns_addrinfo *dns_ai_open(const char *host, const char *serv, enum dns_type qtype, const struct addrinfo *hints, struct dns_resolver *res, int *_error) {
static const struct dns_addrinfo ai_initializer;
struct dns_addrinfo *ai;
int error;
if (res) {
dns_res_acquire(res);
} else if (!(hints->ai_flags & AI_NUMERICHOST)) {
/*
* NOTE: it's assumed that *_error is set from a previous
* API function call, such as dns_res_stub(). Should change
* this semantic, but it's applied elsewhere, too.
*/
if (!*_error)
*_error = EINVAL;
return NULL;
}
if (!(ai = malloc(sizeof *ai)))
goto syerr;
*ai = ai_initializer;
ai->hints = *hints;
ai->res = res;
res = NULL;
if (sizeof ai->qname <= dns_strlcpy(ai->qname, host, sizeof ai->qname))
{ error = ENAMETOOLONG; goto error; }
ai->qtype = qtype;
ai->qport = 0;
if (serv && (error = dns_ai_parseport(&ai->qport, serv, hints)))
goto error;
ai->port = ai->qport;
/*
* FIXME: If an explicit A or AAAA record type conflicts with
* .ai_family or with resconf.family (i.e. AAAA specified but
* AF_INET6 not in interection of .ai_family and resconf.family),
* then what?
*/
switch (ai->qtype) {
case DNS_T_A:
ai->af.todo = DNS_AI_AF2INDEX(AF_INET);
break;
case DNS_T_AAAA:
ai->af.todo = DNS_AI_AF2INDEX(AF_INET6);
break;
default: /* 0, MX, SRV, etc */
switch (ai->hints.ai_family) {
case AF_UNSPEC:
ai->af.todo = DNS_AI_AF2INDEX(AF_INET) | DNS_AI_AF2INDEX(AF_INET6);
break;
case AF_INET:
ai->af.todo = DNS_AI_AF2INDEX(AF_INET);
break;
case AF_INET6:
ai->af.todo = DNS_AI_AF2INDEX(AF_INET6);
break;
default:
break;
}
}
return ai;
syerr:
error = dns_syerr();
error:
*_error = error;
dns_ai_close(ai);
dns_res_close(res);
return NULL;
} /* dns_ai_open() */
void dns_ai_close(struct dns_addrinfo *ai) {
if (!ai)
return;
dns_res_close(ai->res);
dns_trace_close(ai->trace);
if (ai->answer != ai->glue)
dns_p_free(ai->glue);
dns_p_free(ai->answer);
free(ai);
} /* dns_ai_close() */
static int dns_ai_setent(struct addrinfo **ent, union dns_any *any, enum dns_type type, struct dns_addrinfo *ai) {
union u {
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
struct sockaddr_storage ss;
} addr;
const char *cname;
size_t clen;
switch (type) {
case DNS_T_A:
memset(&addr.sin, '\0', sizeof addr.sin);
addr.sin.sin_family = AF_INET;
addr.sin.sin_port = htons(ai->port);
memcpy(&addr.sin.sin_addr, any, sizeof addr.sin.sin_addr);
break;
case DNS_T_AAAA:
memset(&addr.sin6, '\0', sizeof addr.sin6);
addr.sin6.sin6_family = AF_INET6;
addr.sin6.sin6_port = htons(ai->port);
memcpy(&addr.sin6.sin6_addr, any, sizeof addr.sin6.sin6_addr);
break;
default:
return EINVAL;
} /* switch() */
if (ai->hints.ai_flags & AI_CANONNAME) {
cname = (*ai->cname)? ai->cname : ai->qname;
clen = strlen(cname);
} else {
cname = NULL;
clen = 0;
}
if (!(*ent = malloc(sizeof **ent + dns_sa_len(&addr) + ((ai->hints.ai_flags & AI_CANONNAME)? clen + 1 : 0))))
return dns_syerr();
memset(*ent, '\0', sizeof **ent);
(*ent)->ai_family = addr.ss.ss_family;
(*ent)->ai_socktype = ai->hints.ai_socktype;
(*ent)->ai_protocol = ai->hints.ai_protocol;
(*ent)->ai_addr = memcpy((unsigned char *)*ent + sizeof **ent, &addr, dns_sa_len(&addr));
(*ent)->ai_addrlen = dns_sa_len(&addr);
if (ai->hints.ai_flags & AI_CANONNAME)
(*ent)->ai_canonname = memcpy((unsigned char *)*ent + sizeof **ent + dns_sa_len(&addr), cname, clen + 1);
ai->found++;
return 0;
} /* dns_ai_setent() */
enum dns_ai_state {
DNS_AI_S_INIT,
DNS_AI_S_NEXTAF,
DNS_AI_S_NUMERIC,
DNS_AI_S_SUBMIT,
DNS_AI_S_CHECK,
DNS_AI_S_FETCH,
DNS_AI_S_FOREACH_I,
DNS_AI_S_INIT_G,
DNS_AI_S_ITERATE_G,
DNS_AI_S_FOREACH_G,
DNS_AI_S_SUBMIT_G,
DNS_AI_S_CHECK_G,
DNS_AI_S_FETCH_G,
DNS_AI_S_DONE,
}; /* enum dns_ai_state */
#define dns_ai_goto(which) do { ai->state = (which); goto exec; } while (0)
int dns_ai_nextent(struct addrinfo **ent, struct dns_addrinfo *ai) {
struct dns_packet *ans, *glue;
struct dns_rr rr;
char qname[DNS_D_MAXNAME + 1];
union dns_any any;
size_t qlen, clen;
int error;
*ent = 0;
exec:
switch (ai->state) {
case DNS_AI_S_INIT:
ai->state++; /* FALL THROUGH */
case DNS_AI_S_NEXTAF:
if (!dns_ai_nextaf(ai))
dns_ai_goto(DNS_AI_S_DONE);
ai->state++; /* FALL THROUGH */
case DNS_AI_S_NUMERIC:
if (1 == dns_inet_pton(AF_INET, ai->qname, &any.a)) {
if (ai->af.atype == AF_INET) {
ai->state = DNS_AI_S_NEXTAF;
return dns_ai_setent(ent, &any, DNS_T_A, ai);
} else {
dns_ai_goto(DNS_AI_S_NEXTAF);
}
}
if (1 == dns_inet_pton(AF_INET6, ai->qname, &any.aaaa)) {
if (ai->af.atype == AF_INET6) {
ai->state = DNS_AI_S_NEXTAF;
return dns_ai_setent(ent, &any, DNS_T_AAAA, ai);
} else {
dns_ai_goto(DNS_AI_S_NEXTAF);
}
}
if (ai->hints.ai_flags & AI_NUMERICHOST)
dns_ai_goto(DNS_AI_S_NEXTAF);
ai->state++; /* FALL THROUGH */
case DNS_AI_S_SUBMIT:
assert(ai->res);
if ((error = dns_res_submit(ai->res, ai->qname, dns_ai_qtype(ai), DNS_C_IN)))
return error;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_CHECK:
if ((error = dns_res_check(ai->res)))
return error;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_FETCH:
if (!(ans = dns_res_fetch_and_study(ai->res, &error)))
return error;
if (ai->glue != ai->answer)
dns_p_free(ai->glue);
ai->glue = dns_p_movptr(&ai->answer, &ans);
/* Search generator may have changed the qname. */
if (!(qlen = dns_d_expand(qname, sizeof qname, 12, ai->answer, &error)))
return error;
else if (qlen >= sizeof qname)
return DNS_EILLEGAL;
if (!dns_d_cname(ai->cname, sizeof ai->cname, qname, qlen, ai->answer, &error))
return error;
dns_strlcpy(ai->i_cname, ai->cname, sizeof ai->i_cname);
dns_rr_i_init(&ai->i, ai->answer);
ai->i.section = DNS_S_AN;
ai->i.name = ai->i_cname;
ai->i.type = dns_ai_qtype(ai);
ai->i.sort = &dns_rr_i_order;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_FOREACH_I:
if (!dns_rr_grep(&rr, 1, &ai->i, ai->answer, &error))
dns_ai_goto(DNS_AI_S_NEXTAF);
if ((error = dns_any_parse(&any, &rr, ai->answer)))
return error;
ai->port = ai->qport;
switch (rr.type) {
case DNS_T_A:
case DNS_T_AAAA:
return dns_ai_setent(ent, &any, rr.type, ai);
default:
if (!(clen = dns_any_cname(ai->cname, sizeof ai->cname, &any, rr.type)))
dns_ai_goto(DNS_AI_S_FOREACH_I);
/*
* Find the "real" canonical name. Some authorities
* publish aliases where an RFC defines a canonical
* name. We trust that the resolver followed any
* CNAME chains on it's own, regardless of whether
* the "smart" option is enabled.
*/
if (!dns_d_cname(ai->cname, sizeof ai->cname, ai->cname, clen, ai->answer, &error))
return error;
if (rr.type == DNS_T_SRV)
ai->port = any.srv.port;
break;
} /* switch() */
ai->state++; /* FALL THROUGH */
case DNS_AI_S_INIT_G:
ai->g_depth = 0;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_ITERATE_G:
dns_strlcpy(ai->g_cname, ai->cname, sizeof ai->g_cname);
dns_rr_i_init(&ai->g, ai->glue);
ai->g.section = DNS_S_ALL & ~DNS_S_QD;
ai->g.name = ai->g_cname;
ai->g.type = ai->af.qtype;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_FOREACH_G:
if (!dns_rr_grep(&rr, 1, &ai->g, ai->glue, &error)) {
if (dns_rr_i_count(&ai->g) > 0)
dns_ai_goto(DNS_AI_S_FOREACH_I);
else
dns_ai_goto(DNS_AI_S_SUBMIT_G);
}
if ((error = dns_any_parse(&any, &rr, ai->glue)))
return error;
return dns_ai_setent(ent, &any, rr.type, ai);
case DNS_AI_S_SUBMIT_G:
/* skip if already queried */
if (dns_rr_grep(&rr, 1, dns_rr_i_new(ai->glue, .section = DNS_S_QD, .name = ai->g.name, .type = ai->g.type), ai->glue, &error))
dns_ai_goto(DNS_AI_S_FOREACH_I);
/* skip if we recursed (CNAME chains should have been handled in the resolver) */
if (++ai->g_depth > 1)
dns_ai_goto(DNS_AI_S_FOREACH_I);
if ((error = dns_res_submit(ai->res, ai->g.name, ai->g.type, DNS_C_IN)))
return error;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_CHECK_G:
if ((error = dns_res_check(ai->res)))
return error;
ai->state++; /* FALL THROUGH */
case DNS_AI_S_FETCH_G:
if (!(ans = dns_res_fetch_and_study(ai->res, &error)))
return error;
glue = dns_p_merge(ai->glue, DNS_S_ALL, ans, DNS_S_ALL, &error);
dns_p_setptr(&ans, NULL);
if (!glue)
return error;
if (ai->glue != ai->answer)
dns_p_free(ai->glue);
ai->glue = glue;
if (!dns_d_cname(ai->cname, sizeof ai->cname, ai->g.name, strlen(ai->g.name), ai->glue, &error))
dns_ai_goto(DNS_AI_S_FOREACH_I);
dns_ai_goto(DNS_AI_S_ITERATE_G);
case DNS_AI_S_DONE:
if (ai->found) {
return ENOENT; /* TODO: Just return 0 */
} else if (ai->answer) {
switch (dns_p_rcode(ai->answer)) {
case DNS_RC_NOERROR:
/* FALL THROUGH */
case DNS_RC_NXDOMAIN:
return DNS_ENONAME;
default:
return DNS_EFAIL;
}
} else {
return DNS_EFAIL;
}
default:
return EINVAL;
} /* switch() */
} /* dns_ai_nextent() */
time_t dns_ai_elapsed(struct dns_addrinfo *ai) {
return (ai->res)? dns_res_elapsed(ai->res) : 0;
} /* dns_ai_elapsed() */
void dns_ai_clear(struct dns_addrinfo *ai) {
if (ai->res)
dns_res_clear(ai->res);
} /* dns_ai_clear() */
int dns_ai_events(struct dns_addrinfo *ai) {
return (ai->res)? dns_res_events(ai->res) : 0;
} /* dns_ai_events() */
int dns_ai_pollfd(struct dns_addrinfo *ai) {
return (ai->res)? dns_res_pollfd(ai->res) : -1;
} /* dns_ai_pollfd() */
time_t dns_ai_timeout(struct dns_addrinfo *ai) {
return (ai->res)? dns_res_timeout(ai->res) : 0;
} /* dns_ai_timeout() */
int dns_ai_poll(struct dns_addrinfo *ai, int timeout) {
return (ai->res)? dns_res_poll(ai->res, timeout) : 0;
} /* dns_ai_poll() */
size_t dns_ai_print(void *_dst, size_t lim, struct addrinfo *ent, struct dns_addrinfo *ai) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
char addr[DNS_PP_MAX(INET_ADDRSTRLEN, INET6_ADDRSTRLEN) + 1];
dns_b_puts(&dst, "[ ");
dns_b_puts(&dst, ai->qname);
dns_b_puts(&dst, " IN ");
if (ai->qtype) {
dns_b_puts(&dst, dns_strtype(ai->qtype));
} else if (ent->ai_family == AF_INET) {
dns_b_puts(&dst, dns_strtype(DNS_T_A));
} else if (ent->ai_family == AF_INET6) {
dns_b_puts(&dst, dns_strtype(DNS_T_AAAA));
} else {
dns_b_puts(&dst, "0");
}
dns_b_puts(&dst, " ]\n");
dns_b_puts(&dst, ".ai_family = ");
switch (ent->ai_family) {
case AF_INET:
dns_b_puts(&dst, "AF_INET");
break;
case AF_INET6:
dns_b_puts(&dst, "AF_INET6");
break;
default:
dns_b_fmtju(&dst, ent->ai_family, 0);
break;
}
dns_b_putc(&dst, '\n');
dns_b_puts(&dst, ".ai_socktype = ");
switch (ent->ai_socktype) {
case SOCK_STREAM:
dns_b_puts(&dst, "SOCK_STREAM");
break;
case SOCK_DGRAM:
dns_b_puts(&dst, "SOCK_DGRAM");
break;
default:
dns_b_fmtju(&dst, ent->ai_socktype, 0);
break;
}
dns_b_putc(&dst, '\n');
dns_inet_ntop(dns_sa_family(ent->ai_addr), dns_sa_addr(dns_sa_family(ent->ai_addr), ent->ai_addr, NULL), addr, sizeof addr);
dns_b_puts(&dst, ".ai_addr = [");
dns_b_puts(&dst, addr);
dns_b_puts(&dst, "]:");
dns_b_fmtju(&dst, ntohs(*dns_sa_port(dns_sa_family(ent->ai_addr), ent->ai_addr)), 0);
dns_b_putc(&dst, '\n');
dns_b_puts(&dst, ".ai_canonname = ");
dns_b_puts(&dst, (ent->ai_canonname)? ent->ai_canonname : "[NULL]");
dns_b_putc(&dst, '\n');
return dns_b_strllen(&dst);
} /* dns_ai_print() */
const struct dns_stat *dns_ai_stat(struct dns_addrinfo *ai) {
return (ai->res)? dns_res_stat(ai->res) : &ai->st;
} /* dns_ai_stat() */
struct dns_trace *dns_ai_trace(struct dns_addrinfo *ai) {
return ai->trace;
} /* dns_ai_trace() */
void dns_ai_settrace(struct dns_addrinfo *ai, struct dns_trace *trace) {
struct dns_trace *otrace = ai->trace;
ai->trace = dns_trace_acquire_p(trace);
dns_trace_close(otrace);
if (ai->res)
dns_res_settrace(ai->res, trace);
} /* dns_ai_settrace() */
/*
* M I S C E L L A N E O U S R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
static const struct {
char name[16];
enum dns_section type;
} dns_sections[] = {
{ "QUESTION", DNS_S_QUESTION },
{ "QD", DNS_S_QUESTION },
{ "ANSWER", DNS_S_ANSWER },
{ "AN", DNS_S_ANSWER },
{ "AUTHORITY", DNS_S_AUTHORITY },
{ "NS", DNS_S_AUTHORITY },
{ "ADDITIONAL", DNS_S_ADDITIONAL },
{ "AR", DNS_S_ADDITIONAL },
};
const char *(dns_strsection)(enum dns_section section, void *_dst, size_t lim) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned i;
for (i = 0; i < lengthof(dns_sections); i++) {
if (dns_sections[i].type & section) {
dns_b_puts(&dst, dns_sections[i].name);
section &= ~dns_sections[i].type;
if (section)
dns_b_putc(&dst, '|');
}
}
if (section || dst.p == dst.base)
dns_b_fmtju(&dst, (0xffff & section), 0);
return dns_b_tostring(&dst);
} /* dns_strsection() */
enum dns_section dns_isection(const char *src) {
enum dns_section section = 0;
char sbuf[128];
char *name, *next;
unsigned i;
dns_strlcpy(sbuf, src, sizeof sbuf);
next = sbuf;
while ((name = dns_strsep(&next, "|+, \t"))) {
for (i = 0; i < lengthof(dns_sections); i++) {
if (!strcasecmp(dns_sections[i].name, name)) {
section |= dns_sections[i].type;
break;
}
}
}
return section;
} /* dns_isection() */
static const struct {
char name[8];
enum dns_class type;
} dns_classes[] = {
{ "IN", DNS_C_IN },
};
const char *(dns_strclass)(enum dns_class type, void *_dst, size_t lim) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned i;
for (i = 0; i < lengthof(dns_classes); i++) {
if (dns_classes[i].type == type) {
dns_b_puts(&dst, dns_classes[i].name);
break;
}
}
if (dst.p == dst.base)
dns_b_fmtju(&dst, (0xffff & type), 0);
return dns_b_tostring(&dst);
} /* dns_strclass() */
enum dns_class dns_iclass(const char *name) {
unsigned i, class;
for (i = 0; i < lengthof(dns_classes); i++) {
if (!strcasecmp(dns_classes[i].name, name))
return dns_classes[i].type;
}
class = 0;
while (dns_isdigit(*name)) {
class *= 10;
class += *name++ - '0';
}
return DNS_PP_MIN(class, 0xffff);
} /* dns_iclass() */
const char *(dns_strtype)(enum dns_type type, void *_dst, size_t lim) {
struct dns_buf dst = DNS_B_INTO(_dst, lim);
unsigned i;
for (i = 0; i < lengthof(dns_rrtypes); i++) {
if (dns_rrtypes[i].type == type) {
dns_b_puts(&dst, dns_rrtypes[i].name);
break;
}
}
if (dst.p == dst.base)
dns_b_fmtju(&dst, (0xffff & type), 0);
return dns_b_tostring(&dst);
} /* dns_strtype() */
enum dns_type dns_itype(const char *name) {
unsigned i, type;
for (i = 0; i < lengthof(dns_rrtypes); i++) {
if (!strcasecmp(dns_rrtypes[i].name, name))
return dns_rrtypes[i].type;
}
type = 0;
while (dns_isdigit(*name)) {
type *= 10;
type += *name++ - '0';
}
return DNS_PP_MIN(type, 0xffff);
} /* dns_itype() */
static char dns_opcodes[16][16] = {
[DNS_OP_QUERY] = "QUERY",
[DNS_OP_IQUERY] = "IQUERY",
[DNS_OP_STATUS] = "STATUS",
[DNS_OP_NOTIFY] = "NOTIFY",
[DNS_OP_UPDATE] = "UPDATE",
};
static const char *dns__strcode(int code, volatile char *dst, size_t lim) {
char _tmp[48] = "";
struct dns_buf tmp;
size_t p;
assert(lim > 0);
dns_b_fmtju(dns_b_into(&tmp, _tmp, DNS_PP_MIN(sizeof _tmp, lim - 1)), code, 0);
/* copy downwards so first byte is copied last (see below) */
p = (size_t)(tmp.p - tmp.base);
dst[p] = '\0';
while (p--)
dst[p] = _tmp[p];
return (const char *)dst;
}
const char *dns_stropcode(enum dns_opcode opcode) {
opcode = (unsigned)opcode % lengthof(dns_opcodes);
if ('\0' == dns_opcodes[opcode][0])
return dns__strcode(opcode, dns_opcodes[opcode], sizeof dns_opcodes[opcode]);
return dns_opcodes[opcode];
} /* dns_stropcode() */
enum dns_opcode dns_iopcode(const char *name) {
unsigned opcode;
for (opcode = 0; opcode < lengthof(dns_opcodes); opcode++) {
if (!strcasecmp(name, dns_opcodes[opcode]))
return opcode;
}
opcode = 0;
while (dns_isdigit(*name)) {
opcode *= 10;
opcode += *name++ - '0';
}
return DNS_PP_MIN(opcode, 0x0f);
} /* dns_iopcode() */
static char dns_rcodes[32][16] = {
[DNS_RC_NOERROR] = "NOERROR",
[DNS_RC_FORMERR] = "FORMERR",
[DNS_RC_SERVFAIL] = "SERVFAIL",
[DNS_RC_NXDOMAIN] = "NXDOMAIN",
[DNS_RC_NOTIMP] = "NOTIMP",
[DNS_RC_REFUSED] = "REFUSED",
[DNS_RC_YXDOMAIN] = "YXDOMAIN",
[DNS_RC_YXRRSET] = "YXRRSET",
[DNS_RC_NXRRSET] = "NXRRSET",
[DNS_RC_NOTAUTH] = "NOTAUTH",
[DNS_RC_NOTZONE] = "NOTZONE",
/* EDNS(0) extended RCODEs ... */
[DNS_RC_BADVERS] = "BADVERS",
};
const char *dns_strrcode(enum dns_rcode rcode) {
rcode = (unsigned)rcode % lengthof(dns_rcodes);
if ('\0' == dns_rcodes[rcode][0])
return dns__strcode(rcode, dns_rcodes[rcode], sizeof dns_rcodes[rcode]);
return dns_rcodes[rcode];
} /* dns_strrcode() */
enum dns_rcode dns_ircode(const char *name) {
unsigned rcode;
for (rcode = 0; rcode < lengthof(dns_rcodes); rcode++) {
if (!strcasecmp(name, dns_rcodes[rcode]))
return rcode;
}
rcode = 0;
while (dns_isdigit(*name)) {
rcode *= 10;
rcode += *name++ - '0';
}
return DNS_PP_MIN(rcode, 0xfff);
} /* dns_ircode() */
/*
* C O M M A N D - L I N E / R E G R E S S I O N R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#if DNS_MAIN
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#if _WIN32
#include <getopt.h>
#endif
#if !_WIN32
#include <err.h>
#endif
struct {
struct {
const char *path[8];
unsigned count;
} resconf, nssconf, hosts, cache;
const char *qname;
enum dns_type qtype;
int (*sort)();
const char *trace;
int verbose;
struct {
struct dns_resolv_conf *resconf;
struct dns_hosts *hosts;
struct dns_trace *trace;
} memo;
struct sockaddr_storage socks_host;
const char *socks_user;
const char *socks_password;
} MAIN = {
.sort = &dns_rr_i_packet,
};
static void hexdump(const unsigned char *src, size_t len, FILE *fp) {
struct dns_hxd_lines_i lines = { 0 };
char line[128];
while (dns_hxd_lines(line, sizeof line, src, len, &lines)) {
fputs(line, fp);
}
} /* hexdump() */
DNS_NORETURN static void panic(const char *fmt, ...) {
va_list ap;
va_start(ap, fmt);
#if _WIN32
vfprintf(stderr, fmt, ap);
exit(EXIT_FAILURE);
#else
verrx(EXIT_FAILURE, fmt, ap);
#endif
} /* panic() */
#define panic_(fn, ln, fmt, ...) \
panic(fmt "%0s", (fn), (ln), __VA_ARGS__)
#define panic(...) \
panic_(__func__, __LINE__, "(%s:%d) " __VA_ARGS__, "")
static void *grow(unsigned char *p, size_t size) {
void *tmp;
if (!(tmp = realloc(p, size)))
panic("realloc(%"PRIuZ"): %s", size, dns_strerror(errno));
return tmp;
} /* grow() */
static size_t add(size_t a, size_t b) {
if (~a < b)
panic("%"PRIuZ" + %"PRIuZ": integer overflow", a, b);
return a + b;
} /* add() */
static size_t append(unsigned char **dst, size_t osize, const void *src, size_t len) {
size_t size = add(osize, len);
*dst = grow(*dst, size);
memcpy(*dst + osize, src, len);
return size;
} /* append() */
static size_t slurp(unsigned char **dst, size_t osize, FILE *fp, const char *path) {
size_t size = osize;
unsigned char buf[1024];
size_t count;
while ((count = fread(buf, 1, sizeof buf, fp)))
size = append(dst, size, buf, count);
if (ferror(fp))
panic("%s: %s", path, dns_strerror(errno));
return size;
} /* slurp() */
static struct dns_resolv_conf *resconf(void) {
struct dns_resolv_conf **resconf = &MAIN.memo.resconf;
const char *path;
unsigned i;
int error;
if (*resconf)
return *resconf;
if (!(*resconf = dns_resconf_open(&error)))
panic("dns_resconf_open: %s", dns_strerror(error));
if (!MAIN.resconf.count)
MAIN.resconf.path[MAIN.resconf.count++] = "/etc/resolv.conf";
for (i = 0; i < MAIN.resconf.count; i++) {
path = MAIN.resconf.path[i];
if (0 == strcmp(path, "-"))
error = dns_resconf_loadfile(*resconf, stdin);
else
error = dns_resconf_loadpath(*resconf, path);
if (error)
panic("%s: %s", path, dns_strerror(error));
}
for (i = 0; i < MAIN.nssconf.count; i++) {
path = MAIN.nssconf.path[i];
if (0 == strcmp(path, "-"))
error = dns_nssconf_loadfile(*resconf, stdin);
else
error = dns_nssconf_loadpath(*resconf, path);
if (error)
panic("%s: %s", path, dns_strerror(error));
}
if (!MAIN.nssconf.count) {
path = "/etc/nsswitch.conf";
if (!(error = dns_nssconf_loadpath(*resconf, path)))
MAIN.nssconf.path[MAIN.nssconf.count++] = path;
else if (error != ENOENT)
panic("%s: %s", path, dns_strerror(error));
}
return *resconf;
} /* resconf() */
static struct dns_hosts *hosts(void) {
struct dns_hosts **hosts = &MAIN.memo.hosts;
const char *path;
unsigned i;
int error;
if (*hosts)
return *hosts;
if (!MAIN.hosts.count) {
MAIN.hosts.path[MAIN.hosts.count++] = "/etc/hosts";
/* Explicitly test dns_hosts_local() */
if (!(*hosts = dns_hosts_local(&error)))
panic("%s: %s", "/etc/hosts", dns_strerror(error));
return *hosts;
}
if (!(*hosts = dns_hosts_open(&error)))
panic("dns_hosts_open: %s", dns_strerror(error));
for (i = 0; i < MAIN.hosts.count; i++) {
path = MAIN.hosts.path[i];
if (0 == strcmp(path, "-"))
error = dns_hosts_loadfile(*hosts, stdin);
else
error = dns_hosts_loadpath(*hosts, path);
if (error)
panic("%s: %s", path, dns_strerror(error));
}
return *hosts;
} /* hosts() */
#if DNS_CACHE
#include "cache.h"
static struct dns_cache *cache(void) {
static struct cache *cache;
const char *path;
unsigned i;
int error;
if (cache)
return cache_resi(cache);
if (!MAIN.cache.count)
return NULL;
if (!(cache = cache_open(&error)))
panic("%s: %s", MAIN.cache.path[0], dns_strerror(error));
for (i = 0; i < MAIN.cache.count; i++) {
path = MAIN.cache.path[i];
if (!strcmp(path, "-")) {
if ((error = cache_loadfile(cache, stdin, NULL, 0)))
panic("%s: %s", path, dns_strerror(error));
} else if ((error = cache_loadpath(cache, path, NULL, 0)))
panic("%s: %s", path, dns_strerror(error));
}
return cache_resi(cache);
} /* cache() */
#else
static struct dns_cache *cache(void) { return NULL; }
#endif
static struct dns_trace *trace(const char *mode) {
static char omode[64] = "";
struct dns_trace **trace = &MAIN.memo.trace;
FILE *fp;
int error;
if (*trace && 0 == strcmp(omode, mode))
return *trace;
if (!MAIN.trace)
return NULL;
if (!(fp = fopen(MAIN.trace, mode)))
panic("%s: %s", MAIN.trace, strerror(errno));
dns_trace_close(*trace);
if (!(*trace = dns_trace_open(fp, &error)))
panic("%s: %s", MAIN.trace, dns_strerror(error));
dns_strlcpy(omode, mode, sizeof omode);
return *trace;
}
static void print_packet(struct dns_packet *P, FILE *fp) {
dns_p_dump3(P, dns_rr_i_new(P, .sort = MAIN.sort), fp);
if (MAIN.verbose > 2)
hexdump(P->data, P->end, fp);
} /* print_packet() */
static int parse_packet(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
struct dns_packet *P = dns_p_new(512);
struct dns_packet *Q = dns_p_new(512);
enum dns_section section;
struct dns_rr rr;
int error;
union dns_any any;
char pretty[sizeof any * 2];
size_t len;
P->end = fread(P->data, 1, P->size, stdin);
fputs(";; [HEADER]\n", stdout);
fprintf(stdout, ";; qr : %s(%d)\n", (dns_header(P)->qr)? "RESPONSE" : "QUERY", dns_header(P)->qr);
fprintf(stdout, ";; opcode : %s(%d)\n", dns_stropcode(dns_header(P)->opcode), dns_header(P)->opcode);
fprintf(stdout, ";; aa : %s(%d)\n", (dns_header(P)->aa)? "AUTHORITATIVE" : "NON-AUTHORITATIVE", dns_header(P)->aa);
fprintf(stdout, ";; tc : %s(%d)\n", (dns_header(P)->tc)? "TRUNCATED" : "NOT-TRUNCATED", dns_header(P)->tc);
fprintf(stdout, ";; rd : %s(%d)\n", (dns_header(P)->rd)? "RECURSION-DESIRED" : "RECURSION-NOT-DESIRED", dns_header(P)->rd);
fprintf(stdout, ";; ra : %s(%d)\n", (dns_header(P)->ra)? "RECURSION-ALLOWED" : "RECURSION-NOT-ALLOWED", dns_header(P)->ra);
fprintf(stdout, ";; rcode : %s(%d)\n", dns_strrcode(dns_p_rcode(P)), dns_p_rcode(P));
section = 0;
dns_rr_foreach(&rr, P, .sort = MAIN.sort) {
if (section != rr.section)
fprintf(stdout, "\n;; [%s:%d]\n", dns_strsection(rr.section), dns_p_count(P, rr.section));
if ((len = dns_rr_print(pretty, sizeof pretty, &rr, P, &error)))
fprintf(stdout, "%s\n", pretty);
dns_rr_copy(Q, &rr, P);
section = rr.section;
}
fputs("; ; ; ; ; ; ; ;\n\n", stdout);
section = 0;
#if 0
dns_rr_foreach(&rr, Q, .name = "ns8.yahoo.com.") {
#else
struct dns_rr rrset[32];
struct dns_rr_i *rri = dns_rr_i_new(Q, .name = dns_d_new("ns8.yahoo.com", DNS_D_ANCHOR), .sort = MAIN.sort);
unsigned rrcount = dns_rr_grep(rrset, lengthof(rrset), rri, Q, &error);
for (unsigned i = 0; i < rrcount; i++) {
rr = rrset[i];
#endif
if (section != rr.section)
fprintf(stdout, "\n;; [%s:%d]\n", dns_strsection(rr.section), dns_p_count(Q, rr.section));
if ((len = dns_rr_print(pretty, sizeof pretty, &rr, Q, &error)))
fprintf(stdout, "%s\n", pretty);
section = rr.section;
}
if (MAIN.verbose > 1) {
fprintf(stderr, "orig:%"PRIuZ"\n", P->end);
hexdump(P->data, P->end, stdout);
fprintf(stderr, "copy:%"PRIuZ"\n", Q->end);
hexdump(Q->data, Q->end, stdout);
}
return 0;
} /* parse_packet() */
static int parse_domain(int argc, char *argv[]) {
char *dn;
dn = (argc > 1)? argv[1] : "f.l.google.com";
printf("[%s]\n", dn);
dn = dns_d_new(dn);
do {
puts(dn);
} while (dns_d_cleave(dn, strlen(dn) + 1, dn, strlen(dn)));
return 0;
} /* parse_domain() */
static int trim_domain(int argc, char **argv) {
for (argc--, argv++; argc > 0; argc--, argv++) {
char name[DNS_D_MAXNAME + 1];
dns_d_trim(name, sizeof name, *argv, strlen(*argv), DNS_D_ANCHOR);
puts(name);
}
return 0;
} /* trim_domain() */
static int expand_domain(int argc, char *argv[]) {
unsigned short rp = 0;
unsigned char *src = NULL;
unsigned char *dst;
struct dns_packet *pkt;
size_t lim = 0, len;
int error;
if (argc > 1)
rp = atoi(argv[1]);
len = slurp(&src, 0, stdin, "-");
if (!(pkt = dns_p_make(len, &error)))
panic("malloc(%"PRIuZ"): %s", len, dns_strerror(error));
memcpy(pkt->data, src, len);
pkt->end = len;
lim = 1;
dst = grow(NULL, lim);
while (lim <= (len = dns_d_expand(dst, lim, rp, pkt, &error))) {
lim = add(len, 1);
dst = grow(dst, lim);
}
if (!len)
panic("expand: %s", dns_strerror(error));
fwrite(dst, 1, len, stdout);
fflush(stdout);
free(src);
free(dst);
free(pkt);
return 0;
} /* expand_domain() */
static int show_resconf(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
unsigned i;
resconf(); /* load it */
fputs("; SOURCES\n", stdout);
for (i = 0; i < MAIN.resconf.count; i++)
fprintf(stdout, "; %s\n", MAIN.resconf.path[i]);
for (i = 0; i < MAIN.nssconf.count; i++)
fprintf(stdout, "; %s\n", MAIN.nssconf.path[i]);
fputs(";\n", stdout);
dns_resconf_dump(resconf(), stdout);
return 0;
} /* show_resconf() */
static int show_nssconf(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
unsigned i;
resconf();
fputs("# SOURCES\n", stdout);
for (i = 0; i < MAIN.resconf.count; i++)
fprintf(stdout, "# %s\n", MAIN.resconf.path[i]);
for (i = 0; i < MAIN.nssconf.count; i++)
fprintf(stdout, "# %s\n", MAIN.nssconf.path[i]);
fputs("#\n", stdout);
dns_nssconf_dump(resconf(), stdout);
return 0;
} /* show_nssconf() */
static int show_hosts(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
unsigned i;
hosts();
fputs("# SOURCES\n", stdout);
for (i = 0; i < MAIN.hosts.count; i++)
fprintf(stdout, "# %s\n", MAIN.hosts.path[i]);
fputs("#\n", stdout);
dns_hosts_dump(hosts(), stdout);
return 0;
} /* show_hosts() */
static int query_hosts(int argc, char *argv[]) {
struct dns_packet *Q = dns_p_new(512);
struct dns_packet *A;
char qname[DNS_D_MAXNAME + 1];
size_t qlen;
int error;
if (!MAIN.qname)
MAIN.qname = (argc > 1)? argv[1] : "localhost";
if (!MAIN.qtype)
MAIN.qtype = DNS_T_A;
hosts();
if (MAIN.qtype == DNS_T_PTR && !strstr(MAIN.qname, "arpa")) {
union { struct in_addr a; struct in6_addr a6; } addr;
int af = (strchr(MAIN.qname, ':'))? AF_INET6 : AF_INET;
if ((error = dns_pton(af, MAIN.qname, &addr)))
panic("%s: %s", MAIN.qname, dns_strerror(error));
qlen = dns_ptr_qname(qname, sizeof qname, af, &addr);
} else
qlen = dns_strlcpy(qname, MAIN.qname, sizeof qname);
if ((error = dns_p_push(Q, DNS_S_QD, qname, qlen, MAIN.qtype, DNS_C_IN, 0, 0)))
panic("%s: %s", qname, dns_strerror(error));
if (!(A = dns_hosts_query(hosts(), Q, &error)))
panic("%s: %s", qname, dns_strerror(error));
print_packet(A, stdout);
free(A);
return 0;
} /* query_hosts() */
static int search_list(int argc, char *argv[]) {
const char *qname = (argc > 1)? argv[1] : "f.l.google.com";
unsigned long i = 0;
char name[DNS_D_MAXNAME + 1];
printf("[%s]\n", qname);
while (dns_resconf_search(name, sizeof name, qname, strlen(qname), resconf(), &i))
puts(name);
return 0;
} /* search_list() */
static int permute_set(int argc, char *argv[]) {
unsigned lo, hi, i;
struct dns_k_permutor p;
hi = (--argc > 0)? atoi(argv[argc]) : 8;
lo = (--argc > 0)? atoi(argv[argc]) : 0;
fprintf(stderr, "[%u .. %u]\n", lo, hi);
dns_k_permutor_init(&p, lo, hi);
for (i = lo; i <= hi; i++)
fprintf(stdout, "%u\n", dns_k_permutor_step(&p));
// printf("%u -> %u -> %u\n", i, dns_k_permutor_E(&p, i), dns_k_permutor_D(&p, dns_k_permutor_E(&p, i)));
return 0;
} /* permute_set() */
static int shuffle_16(int argc, char *argv[]) {
unsigned n, r;
if (--argc > 0) {
n = 0xffff & atoi(argv[argc]);
r = (--argc > 0)? (unsigned)atoi(argv[argc]) : dns_random();
fprintf(stdout, "%hu\n", dns_k_shuffle16(n, r));
} else {
r = dns_random();
for (n = 0; n < 65536; n++)
fprintf(stdout, "%hu\n", dns_k_shuffle16(n, r));
}
return 0;
} /* shuffle_16() */
static int dump_random(int argc, char *argv[]) {
unsigned char b[32];
unsigned i, j, n, r;
n = (argc > 1)? atoi(argv[1]) : 32;
while (n) {
i = 0;
do {
r = dns_random();
for (j = 0; j < sizeof r && i < n && i < sizeof b; i++, j++) {
b[i] = 0xff & r;
r >>= 8;
}
} while (i < n && i < sizeof b);
hexdump(b, i, stdout);
n -= i;
}
return 0;
} /* dump_random() */
static int send_query(int argc, char *argv[]) {
struct dns_packet *A, *Q = dns_p_new(512);
char host[INET6_ADDRSTRLEN + 1];
struct sockaddr_storage ss;
struct dns_socket *so;
int error, type;
memset(&ss, 0, sizeof ss);
if (argc > 1) {
ss.ss_family = (strchr(argv[1], ':'))? AF_INET6 : AF_INET;
if ((error = dns_pton(ss.ss_family, argv[1], dns_sa_addr(ss.ss_family, &ss, NULL))))
panic("%s: %s", argv[1], dns_strerror(error));
*dns_sa_port(ss.ss_family, &ss) = htons(53);
} else
memcpy(&ss, &resconf()->nameserver[0], dns_sa_len(&resconf()->nameserver[0]));
if (!dns_inet_ntop(ss.ss_family, dns_sa_addr(ss.ss_family, &ss, NULL), host, sizeof host))
panic("bad host address, or none provided");
if (!MAIN.qname)
MAIN.qname = "ipv6.google.com";
if (!MAIN.qtype)
MAIN.qtype = DNS_T_AAAA;
if ((error = dns_p_push(Q, DNS_S_QD, MAIN.qname, strlen(MAIN.qname), MAIN.qtype, DNS_C_IN, 0, 0)))
panic("dns_p_push: %s", dns_strerror(error));
dns_header(Q)->rd = 1;
if (strstr(argv[0], "udp"))
type = SOCK_DGRAM;
else if (strstr(argv[0], "tcp"))
type = SOCK_STREAM;
else
type = dns_res_tcp2type(resconf()->options.tcp);
fprintf(stderr, "querying %s for %s IN %s\n", host, MAIN.qname, dns_strtype(MAIN.qtype));
if (!(so = dns_so_open((struct sockaddr *)&resconf()->iface, type, dns_opts(), &error)))
panic("dns_so_open: %s", dns_strerror(error));
while (!(A = dns_so_query(so, Q, (struct sockaddr *)&ss, &error))) {
if (error != DNS_EAGAIN)
panic("dns_so_query: %s (%d)", dns_strerror(error), error);
if (dns_so_elapsed(so) > 10)
panic("query timed-out");
dns_so_poll(so, 1);
}
print_packet(A, stdout);
dns_so_close(so);
return 0;
} /* send_query() */
static int print_arpa(int argc, char *argv[]) {
const char *ip = (argc > 1)? argv[1] : "::1";
int af = (strchr(ip, ':'))? AF_INET6 : AF_INET;
union { struct in_addr a4; struct in6_addr a6; } addr;
char host[DNS_D_MAXNAME + 1];
if (1 != dns_inet_pton(af, ip, &addr) || 0 == dns_ptr_qname(host, sizeof host, af, &addr))
panic("%s: invalid address", ip);
fprintf(stdout, "%s\n", host);
return 0;
} /* print_arpa() */
static int show_hints(int argc, char *argv[]) {
struct dns_hints *(*load)(struct dns_resolv_conf *, int *);
const char *which, *how, *who;
struct dns_hints *hints;
int error;
which = (argc > 1)? argv[1] : "local";
how = (argc > 2)? argv[2] : "plain";
who = (argc > 3)? argv[3] : "google.com";
load = (0 == strcmp(which, "local"))
? &dns_hints_local
: &dns_hints_root;
if (!(hints = load(resconf(), &error)))
panic("%s: %s", argv[0], dns_strerror(error));
if (0 == strcmp(how, "plain")) {
dns_hints_dump(hints, stdout);
} else {
struct dns_packet *query, *answer;
query = dns_p_new(512);
if ((error = dns_p_push(query, DNS_S_QUESTION, who, strlen(who), DNS_T_A, DNS_C_IN, 0, 0)))
panic("%s: %s", who, dns_strerror(error));
if (!(answer = dns_hints_query(hints, query, &error)))
panic("%s: %s", who, dns_strerror(error));
print_packet(answer, stdout);
free(answer);
}
dns_hints_close(hints);
return 0;
} /* show_hints() */
static int resolve_query(int argc DNS_NOTUSED, char *argv[]) {
_Bool recurse = !!strstr(argv[0], "recurse");
struct dns_hints *(*hints)() = (recurse)? &dns_hints_root : &dns_hints_local;
struct dns_resolver *R;
struct dns_packet *ans;
const struct dns_stat *st;
int error;
if (!MAIN.qname)
MAIN.qname = "www.google.com";
if (!MAIN.qtype)
MAIN.qtype = DNS_T_A;
resconf()->options.recurse = recurse;
if (!(R = dns_res_open(resconf(), hosts(), dns_hints_mortal(hints(resconf(), &error)), cache(),
dns_opts(.socks_host=&MAIN.socks_host,
.socks_user=MAIN.socks_user,
.socks_password=MAIN.socks_password), &error)))
panic("%s: %s", MAIN.qname, dns_strerror(error));
dns_res_settrace(R, trace("w+b"));
if ((error = dns_res_submit(R, MAIN.qname, MAIN.qtype, DNS_C_IN)))
panic("%s: %s", MAIN.qname, dns_strerror(error));
while ((error = dns_res_check(R))) {
if (error != DNS_EAGAIN)
panic("dns_res_check: %s (%d)", dns_strerror(error), error);
if (dns_res_elapsed(R) > 30)
panic("query timed-out");
dns_res_poll(R, 1);
}
ans = dns_res_fetch(R, &error);
print_packet(ans, stdout);
free(ans);
st = dns_res_stat(R);
putchar('\n');
printf(";; queries: %"PRIuZ"\n", st->queries);
printf(";; udp sent: %"PRIuZ" in %"PRIuZ" bytes\n", st->udp.sent.count, st->udp.sent.bytes);
printf(";; udp rcvd: %"PRIuZ" in %"PRIuZ" bytes\n", st->udp.rcvd.count, st->udp.rcvd.bytes);
printf(";; tcp sent: %"PRIuZ" in %"PRIuZ" bytes\n", st->tcp.sent.count, st->tcp.sent.bytes);
printf(";; tcp rcvd: %"PRIuZ" in %"PRIuZ" bytes\n", st->tcp.rcvd.count, st->tcp.rcvd.bytes);
dns_res_close(R);
return 0;
} /* resolve_query() */
static int resolve_addrinfo(int argc DNS_NOTUSED, char *argv[]) {
_Bool recurse = !!strstr(argv[0], "recurse");
struct dns_hints *(*hints)() = (recurse)? &dns_hints_root : &dns_hints_local;
struct dns_resolver *res = NULL;
struct dns_addrinfo *ai = NULL;
struct addrinfo ai_hints = { .ai_family = PF_UNSPEC, .ai_socktype = SOCK_STREAM, .ai_flags = AI_CANONNAME };
struct addrinfo *ent;
char pretty[512];
int error;
if (!MAIN.qname)
MAIN.qname = "www.google.com";
/* NB: MAIN.qtype of 0 means obey hints.ai_family */
resconf()->options.recurse = recurse;
if (!(res = dns_res_open(resconf(), hosts(), dns_hints_mortal(hints(resconf(), &error)), cache(), dns_opts(), &error)))
panic("%s: %s", MAIN.qname, dns_strerror(error));
if (!(ai = dns_ai_open(MAIN.qname, "80", MAIN.qtype, &ai_hints, res, &error)))
panic("%s: %s", MAIN.qname, dns_strerror(error));
dns_ai_settrace(ai, trace("w+b"));
do {
switch (error = dns_ai_nextent(&ent, ai)) {
case 0:
dns_ai_print(pretty, sizeof pretty, ent, ai);
fputs(pretty, stdout);
free(ent);
break;
case ENOENT:
break;
case DNS_EAGAIN:
if (dns_ai_elapsed(ai) > 30)
panic("query timed-out");
dns_ai_poll(ai, 1);
break;
default:
panic("dns_ai_nextent: %s (%d)", dns_strerror(error), error);
}
} while (error != ENOENT);
dns_res_close(res);
dns_ai_close(ai);
return 0;
} /* resolve_addrinfo() */
static int dump_trace(int argc DNS_NOTUSED, char *argv[]) {
int error;
if (!MAIN.trace)
panic("no trace file specified");
if ((error = dns_trace_dump(trace("r"), stdout)))
panic("dump_trace: %s", dns_strerror(error));
return 0;
} /* dump_trace() */
static int echo_port(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
union {
struct sockaddr sa;
struct sockaddr_in sin;
} port;
int fd;
memset(&port, 0, sizeof port);
port.sin.sin_family = AF_INET;
port.sin.sin_port = htons(5354);
port.sin.sin_addr.s_addr = inet_addr("127.0.0.1");
if (-1 == (fd = socket(PF_INET, SOCK_DGRAM, 0)))
panic("socket: %s", strerror(errno));
if (0 != bind(fd, &port.sa, sizeof port.sa))
panic("127.0.0.1:5353: %s", dns_strerror(errno));
for (;;) {
struct dns_packet *pkt = dns_p_new(512);
struct sockaddr_storage ss;
socklen_t slen = sizeof ss;
ssize_t count;
#if defined(MSG_WAITALL) /* MinGW issue */
int rflags = MSG_WAITALL;
#else
int rflags = 0;
#endif
count = recvfrom(fd, (char *)pkt->data, pkt->size, rflags, (struct sockaddr *)&ss, &slen);
if (!count || count < 0)
panic("recvfrom: %s", strerror(errno));
pkt->end = count;
dns_p_dump(pkt, stdout);
(void)sendto(fd, (char *)pkt->data, pkt->end, 0, (struct sockaddr *)&ss, slen);
}
return 0;
} /* echo_port() */
static int isection(int argc, char *argv[]) {
const char *name = (argc > 1)? argv[1] : "";
int type;
type = dns_isection(name);
name = dns_strsection(type);
printf("%s (%d)\n", name, type);
return 0;
} /* isection() */
static int iclass(int argc, char *argv[]) {
const char *name = (argc > 1)? argv[1] : "";
int type;
type = dns_iclass(name);
name = dns_strclass(type);
printf("%s (%d)\n", name, type);
return 0;
} /* iclass() */
static int itype(int argc, char *argv[]) {
const char *name = (argc > 1)? argv[1] : "";
int type;
type = dns_itype(name);
name = dns_strtype(type);
printf("%s (%d)\n", name, type);
return 0;
} /* itype() */
static int iopcode(int argc, char *argv[]) {
const char *name = (argc > 1)? argv[1] : "";
int type;
type = dns_iopcode(name);
name = dns_stropcode(type);
printf("%s (%d)\n", name, type);
return 0;
} /* iopcode() */
static int ircode(int argc, char *argv[]) {
const char *name = (argc > 1)? argv[1] : "";
int type;
type = dns_ircode(name);
name = dns_strrcode(type);
printf("%s (%d)\n", name, type);
return 0;
} /* ircode() */
#define SIZE1(x) { DNS_PP_STRINGIFY(x), sizeof (x) }
#define SIZE2(x, ...) SIZE1(x), SIZE1(__VA_ARGS__)
#define SIZE3(x, ...) SIZE1(x), SIZE2(__VA_ARGS__)
#define SIZE4(x, ...) SIZE1(x), SIZE3(__VA_ARGS__)
#define SIZE(...) DNS_PP_CALL(DNS_PP_XPASTE(SIZE, DNS_PP_NARG(__VA_ARGS__)), __VA_ARGS__)
static int sizes(int argc DNS_NOTUSED, char *argv[] DNS_NOTUSED) {
static const struct { const char *name; size_t size; } type[] = {
SIZE(struct dns_header, struct dns_packet, struct dns_rr, struct dns_rr_i),
SIZE(struct dns_a, struct dns_aaaa, struct dns_mx, struct dns_ns),
SIZE(struct dns_cname, struct dns_soa, struct dns_ptr, struct dns_srv),
SIZE(struct dns_sshfp, struct dns_txt, union dns_any),
SIZE(struct dns_resolv_conf, struct dns_hosts, struct dns_hints, struct dns_hints_i),
SIZE(struct dns_options, struct dns_socket, struct dns_resolver, struct dns_addrinfo),
SIZE(struct dns_cache), SIZE(size_t), SIZE(void *), SIZE(long)
};
unsigned i, max;
for (i = 0, max = 0; i < lengthof(type); i++)
max = DNS_PP_MAX(max, strlen(type[i].name));
for (i = 0; i < lengthof(type); i++)
printf("%*s : %"PRIuZ"\n", max, type[i].name, type[i].size);
return 0;
} /* sizes() */
static const struct { const char *cmd; int (*run)(); const char *help; } cmds[] = {
{ "parse-packet", &parse_packet, "parse binary packet from stdin" },
{ "parse-domain", &parse_domain, "anchor and iteratively cleave domain" },
{ "trim-domain", &trim_domain, "trim and anchor domain name" },
{ "expand-domain", &expand_domain, "expand domain at offset NN in packet from stdin" },
{ "show-resconf", &show_resconf, "show resolv.conf data" },
{ "show-hosts", &show_hosts, "show hosts data" },
{ "show-nssconf", &show_nssconf, "show nsswitch.conf data" },
{ "query-hosts", &query_hosts, "query A, AAAA or PTR in hosts data" },
{ "search-list", &search_list, "generate query search list from domain" },
{ "permute-set", &permute_set, "generate random permutation -> (0 .. N or N .. M)" },
{ "shuffle-16", &shuffle_16, "simple 16-bit permutation" },
{ "dump-random", &dump_random, "generate random bytes" },
{ "send-query", &send_query, "send query to host" },
{ "send-query-udp", &send_query, "send udp query to host" },
{ "send-query-tcp", &send_query, "send tcp query to host" },
{ "print-arpa", &print_arpa, "print arpa. zone name of address" },
{ "show-hints", &show_hints, "print hints: show-hints [local|root] [plain|packet]" },
{ "resolve-stub", &resolve_query, "resolve as stub resolver" },
{ "resolve-recurse", &resolve_query, "resolve as recursive resolver" },
{ "addrinfo-stub", &resolve_addrinfo, "resolve through getaddrinfo clone" },
{ "addrinfo-recurse", &resolve_addrinfo, "resolve through getaddrinfo clone" },
/* { "resolve-nameinfo", &resolve_query, "resolve as recursive resolver" }, */
{ "dump-trace", &dump_trace, "dump the contents of a trace file" },
{ "echo", &echo_port, "server echo mode, for nmap fuzzing" },
{ "isection", &isection, "parse section string" },
{ "iclass", &iclass, "parse class string" },
{ "itype", &itype, "parse type string" },
{ "iopcode", &iopcode, "parse opcode string" },
{ "ircode", &ircode, "parse rcode string" },
{ "sizes", &sizes, "print data structure sizes" },
};
static void print_usage(const char *progname, FILE *fp) {
static const char *usage =
" [OPTIONS] COMMAND [ARGS]\n"
" -c PATH Path to resolv.conf\n"
" -n PATH Path to nsswitch.conf\n"
" -l PATH Path to local hosts\n"
" -z PATH Path to zone cache\n"
" -q QNAME Query name\n"
" -t QTYPE Query type\n"
" -s HOW Sort records\n"
" -S ADDR Address of SOCKS server to use\n"
" -P PORT Port of SOCKS server to use\n"
" -A USER:PASSWORD Credentials for the SOCKS server\n"
" -f PATH Path to trace file\n"
" -v Be more verbose (-vv show packets; -vvv hexdump packets)\n"
" -V Print version info\n"
" -h Print this usage message\n"
"\n";
unsigned i, n, m;
fputs(progname, fp);
fputs(usage, fp);
for (i = 0, m = 0; i < lengthof(cmds); i++) {
if (strlen(cmds[i].cmd) > m)
m = strlen(cmds[i].cmd);
}
for (i = 0; i < lengthof(cmds); i++) {
fprintf(fp, " %s ", cmds[i].cmd);
for (n = strlen(cmds[i].cmd); n < m; n++)
putc(' ', fp);
fputs(cmds[i].help, fp);
putc('\n', fp);
}
fputs("\nReport bugs to William Ahern <william@25thandClement.com>\n", fp);
} /* print_usage() */
static void print_version(const char *progname, FILE *fp) {
fprintf(fp, "%s (dns.c) %.8X\n", progname, dns_v_rel());
fprintf(fp, "vendor %s\n", dns_vendor());
fprintf(fp, "release %.8X\n", dns_v_rel());
fprintf(fp, "abi %.8X\n", dns_v_abi());
fprintf(fp, "api %.8X\n", dns_v_api());
} /* print_version() */
static void main_exit(void) {
dns_trace_close(MAIN.memo.trace);
MAIN.memo.trace = NULL;
dns_hosts_close(MAIN.memo.hosts);
MAIN.memo.hosts = NULL;
dns_resconf_close(MAIN.memo.resconf);
MAIN.memo.resconf = NULL;
} /* main_exit() */
int main(int argc, char **argv) {
extern int optind;
extern char *optarg;
const char *progname = argv[0];
unsigned i;
int ch;
atexit(&main_exit);
while (-1 != (ch = getopt(argc, argv, "q:t:c:n:l:z:s:S:P:A:f:vVh"))) {
switch (ch) {
case 'c':
assert(MAIN.resconf.count < lengthof(MAIN.resconf.path));
MAIN.resconf.path[MAIN.resconf.count++] = optarg;
break;
case 'n':
assert(MAIN.nssconf.count < lengthof(MAIN.nssconf.path));
MAIN.nssconf.path[MAIN.nssconf.count++] = optarg;
break;
case 'l':
assert(MAIN.hosts.count < lengthof(MAIN.hosts.path));
MAIN.hosts.path[MAIN.hosts.count++] = optarg;
break;
case 'z':
assert(MAIN.cache.count < lengthof(MAIN.cache.path));
MAIN.cache.path[MAIN.cache.count++] = optarg;
break;
case 'q':
MAIN.qname = optarg;
break;
case 't':
for (i = 0; i < lengthof(dns_rrtypes); i++) {
if (0 == strcasecmp(dns_rrtypes[i].name, optarg))
{ MAIN.qtype = dns_rrtypes[i].type; break; }
}
if (MAIN.qtype)
break;
for (i = 0; dns_isdigit(optarg[i]); i++) {
MAIN.qtype *= 10;
MAIN.qtype += optarg[i] - '0';
}
if (!MAIN.qtype)
panic("%s: invalid query type", optarg);
break;
case 's':
if (0 == strcasecmp(optarg, "packet"))
MAIN.sort = &dns_rr_i_packet;
else if (0 == strcasecmp(optarg, "shuffle"))
MAIN.sort = &dns_rr_i_shuffle;
else if (0 == strcasecmp(optarg, "order"))
MAIN.sort = &dns_rr_i_order;
else
panic("%s: invalid sort method", optarg);
break;
case 'S': {
dns_error_t error;
struct dns_resolv_conf *conf = resconf();
conf->options.tcp = DNS_RESCONF_TCP_SOCKS;
MAIN.socks_host.ss_family = (strchr(optarg, ':')) ? AF_INET6 : AF_INET;
if ((error = dns_pton(MAIN.socks_host.ss_family, optarg,
dns_sa_addr(MAIN.socks_host.ss_family,
&MAIN.socks_host, NULL))))
panic("%s: %s", optarg, dns_strerror(error));
*dns_sa_port(MAIN.socks_host.ss_family, &MAIN.socks_host) = htons(1080);
break;
}
case 'P':
if (! MAIN.socks_host.ss_family)
panic("-P without prior -S");
*dns_sa_port(MAIN.socks_host.ss_family, &MAIN.socks_host) = htons(atoi(optarg));
break;
case 'A': {
char *password;
if (! MAIN.socks_host.ss_family)
panic("-A without prior -S");
if (! (password = strchr(optarg, ':')))
panic("Usage: -A USER:PASSWORD");
*password = 0;
password += 1;
MAIN.socks_user = optarg;
MAIN.socks_password = password;
break;
}
case 'f':
MAIN.trace = optarg;
break;
case 'v':
dns_debug = ++MAIN.verbose;
break;
case 'V':
print_version(progname, stdout);
return 0;
case 'h':
print_usage(progname, stdout);
return 0;
default:
print_usage(progname, stderr);
return EXIT_FAILURE;
} /* switch() */
} /* while() */
argc -= optind;
argv += optind;
for (i = 0; i < lengthof(cmds) && argv[0]; i++) {
if (0 == strcmp(cmds[i].cmd, argv[0]))
return cmds[i].run(argc, argv);
}
print_usage(progname, stderr);
return EXIT_FAILURE;
} /* main() */
#endif /* DNS_MAIN */
/*
* pop file-scoped compiler annotations
*/
#if __clang__
#pragma clang diagnostic pop
#elif DNS_GNUC_PREREQ(4,6,0)
#pragma GCC diagnostic pop
#endif

File Metadata

Mime Type
text/x-c
Expires
Sat, Jul 12, 10:28 AM (1 d, 16 h)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
bd/a2/1b2db726381338e64da59ea4f8c3

Event Timeline