efl/src/lib/ecore_con/dns.c

7879 lines
172 KiB
C
Raw Normal View History

/* ==========================================================================
* dns.c - Recursive, Reentrant DNS Resolver.
* --------------------------------------------------------------------------
* Copyright (c) 2008, 2009, 2010 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.
* ==========================================================================
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#if !defined(__FreeBSD__)
#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 600
#endif
#undef _BSD_SOURCE
#define _BSD_SOURCE
#undef _DARWIN_C_SOURCE
#define _DARWIN_C_SOURCE
#undef _NETBSD_SOURCE
#define _NETBSD_SOURCE
#endif
#include <stddef.h> /* offsetof() */
#include <stdint.h> /* uint32_t */
#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) */
#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) */
#include <signal.h> /* sig_atomic_t */
#include <errno.h> /* errno EINVAL ENOENT */
#undef NDEBUG
#include <assert.h> /* assert(3) */
#if _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#else
#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> /* 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"
/*
* S T A N D A R D M A C R O S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#ifndef MIN
#define MIN(a, b) (((a) < (b))? (a) : (b))
#endif
#ifndef MAX
#define MAX(a, b) (((a) > (b))? (a) : (b))
#endif
#ifndef lengthof
#define lengthof(a) (sizeof (a) / sizeof (a)[0])
#endif
#ifndef endof
#define endof(a) (&(a)[lengthof((a))])
#endif
/*
* D E B U G M A C R O S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
int dns_debug = 0;
#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 */
/*
* 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
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#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";
default:
return strerror(error);
} /* switch() */
} /* dns_strerror() */
/*
* A T O M I C R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
static unsigned dns_atomic_inc(dns_atomic_t *i) {
return (*i)++;
} /* dns_atomic_inc() */
static unsigned dns_atomic_dec(dns_atomic_t *i) {
return (*i)--;
} /* dns_atomic_dec() */
/*
* 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;
assert(1 == RAND_bytes((unsigned char *)&r, sizeof r));
return r;
#else
return DNS_RANDOM();
#endif
} /* dns_random_() */
unsigned (*dns_random)(void) __attribute__((weak)) = &dns_random_;
/*
* 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() */
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() */
/*
* U T I L I T Y R O U T I N E S
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/*
* Monotonic Time
*
*/
static time_t dns_now(void) {
/* XXX: Assumes sizeof (time_t) <= sizeof (sig_atomic_t) */
static volatile sig_atomic_t last, tick;
volatile sig_atomic_t tmp_last, tmp_tick;
time_t now;
time(&now);
tmp_last = last;
if (now > tmp_last) {
tmp_tick = tick;
tmp_tick += now - tmp_last;
tick = tmp_tick;
}
last = now;
return tick;
} /* dns_now() */
static time_t dns_elapsed(time_t from) {
time_t now = dns_now();
return (now > from)? now - from : 0;
} /* dns_elpased() */
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 defined(AF_UNIX) && !defined(_WIN32)
[AF_UNIX] = sizeof (struct sockaddr_un),
#endif
};
return table[af];
} /* dns_af_len() */
#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;
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() */
void *dns_sa_addr(int af, void *sa) {
switch (af) {
case AF_INET6:
return &((struct sockaddr_in6 *)sa)->sin6_addr;
case AF_INET:
return &((struct sockaddr_in *)sa)->sin_addr;
default:
return 0;
}
} /* dns_sa_addr() */
#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() */
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() */
#endif
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() */
#if defined(_WIN32) || defined(__SUNPRO_C)
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 int dns_poll(int fd, short events, int timeout) {
fd_set rset, wset;
if (!events)
return 0;
assert(fd >= 0 && fd < FD_SETSIZE);
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() */
/*
* 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 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 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() */
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 = 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 = 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:
free(M); M = 0;
if (error == DNS_ENOBUFS && bufsiz < 65535) {
bufsiz = 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() */
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;
P->data[P->end++] = 0x7f & (ttl >> 24);
P->data[P->end++] = 0xff & (ttl >> 16);
P->data[P->end++] = 0xff & (ttl >> 8);
P->data[P->end++] = 0xff & (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->qd.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->qdcount = htons(ntohs(dns_header(P)->qdcount) + 1);
P->qd.end = P->end;
P->an.base = P->end;
P->an.end = P->end;
P->ns.base = P->end;
P->ns.end = P->end;
P->ar.base = P->end;
P->ar.end = P->end;
break;
case DNS_S_AN:
if (dns_p_count(P, DNS_S_NS|DNS_S_AR))
goto order;
if (!P->an.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->ancount = htons(ntohs(dns_header(P)->ancount) + 1);
P->an.end = P->end;
P->ns.base = P->end;
P->ns.end = P->end;
P->ar.base = P->end;
P->ar.end = P->end;
break;
case DNS_S_NS:
if (dns_p_count(P, DNS_S_AR))
goto order;
if (!P->ns.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->nscount = htons(ntohs(dns_header(P)->nscount) + 1);
P->ns.end = P->end;
P->ar.base = P->end;
P->ar.end = P->end;
break;
case DNS_S_AR:
if (!P->ar.base && (error = dns_p_study(P)))
goto error;
dns_header(P)->arcount = htons(ntohs(dns_header(P)->arcount) + 1);
P->ar.end = P->end;
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() */
static void dns_p_dump3(struct dns_packet *P, struct dns_rr_i *I, FILE *fp) {
enum dns_section section;
struct dns_rr rr;
int error;
union dns_any any;
char pretty[sizeof any * 2];
size_t len;
fputs(";; [HEADER]\n", fp);
fprintf(fp, ";; qr : %s(%d)\n", (dns_header(P)->qr)? "RESPONSE" : "QUERY", dns_header(P)->qr);
fprintf(fp, ";; opcode : %s(%d)\n", dns_stropcode(dns_header(P)->opcode), dns_header(P)->opcode);
fprintf(fp, ";; aa : %s(%d)\n", (dns_header(P)->aa)? "AUTHORITATIVE" : "NON-AUTHORITATIVE", dns_header(P)->aa);
fprintf(fp, ";; tc : %s(%d)\n", (dns_header(P)->tc)? "TRUNCATED" : "NOT-TRUNCATED", dns_header(P)->tc);
fprintf(fp, ";; rd : %s(%d)\n", (dns_header(P)->rd)? "RECURSION-DESIRED" : "RECURSION-NOT-DESIRED", dns_header(P)->rd);
fprintf(fp, ";; ra : %s(%d)\n", (dns_header(P)->ra)? "RECURSION-ALLOWED" : "RECURSION-NOT-ALLOWED", dns_header(P)->ra);
fprintf(fp, ";; rcode : %s(%d)\n", dns_strrcode(dns_header(P)->rcode), dns_header(P)->rcode);
section = 0;
while (dns_rr_grep(&rr, 1, I, P, &error)) {
if (section != rr.section)
fprintf(fp, "\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(fp, "%s\n", pretty);
section = rr.section;
}
} /* 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_p_unstudy(struct dns_packet *P) {
dns_s_unstudy(&P->qd);
dns_s_unstudy(&P->an);
dns_s_unstudy(&P->ns);
dns_s_unstudy(&P->ar);
} /* dns_p_unstudy() */
static int dns_s_study(struct dns_s_memo *m, enum dns_section section, unsigned 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() */
int dns_p_study(struct dns_packet *P) {
int error;
if ((error = dns_s_study(&P->qd, DNS_S_QD, 12, P)))
goto error;
if ((error = dns_s_study(&P->an, DNS_S_AN, P->qd.end, P)))
goto error;
if ((error = dns_s_study(&P->ns, DNS_S_NS, P->an.end, P)))
goto error;
if ((error = dns_s_study(&P->ar, DNS_S_AR, P->ns.end, P)))
goto error;
return 0;
error:
dns_p_unstudy(P);
return error;
} /* dns_p_study() */
/*
* 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. */