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glibc/resolv/res_send.c

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/*
* Copyright (c) 1985, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/*
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
static const char rcsid[] = "$BINDId: res_send.c,v 8.38 2000/03/30 20:16:51 vixie Exp $";
#endif /* LIBC_SCCS and not lint */
/*
* Send query to name server and wait for reply.
*/
#include <assert.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/poll.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <resolv.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if PACKETSZ > 65536
#define MAXPACKET PACKETSZ
#else
#define MAXPACKET 65536
#endif
/* From ev_streams.c. */
static inline void
__attribute ((always_inline))
evConsIovec(void *buf, size_t cnt, struct iovec *vec) {
memset(vec, 0xf5, sizeof (*vec));
vec->iov_base = buf;
vec->iov_len = cnt;
}
/* From ev_timers.c. */
#define BILLION 1000000000
static inline void
evConsTime(struct timespec *res, time_t sec, long nsec) {
res->tv_sec = sec;
res->tv_nsec = nsec;
}
static inline void
evAddTime(struct timespec *res, const struct timespec *addend1,
const struct timespec *addend2) {
res->tv_sec = addend1->tv_sec + addend2->tv_sec;
res->tv_nsec = addend1->tv_nsec + addend2->tv_nsec;
if (res->tv_nsec >= BILLION) {
res->tv_sec++;
res->tv_nsec -= BILLION;
}
}
static inline void
evSubTime(struct timespec *res, const struct timespec *minuend,
const struct timespec *subtrahend) {
res->tv_sec = minuend->tv_sec - subtrahend->tv_sec;
if (minuend->tv_nsec >= subtrahend->tv_nsec)
res->tv_nsec = minuend->tv_nsec - subtrahend->tv_nsec;
else {
res->tv_nsec = (BILLION
- subtrahend->tv_nsec + minuend->tv_nsec);
res->tv_sec--;
}
}
static inline int
evCmpTime(struct timespec a, struct timespec b) {
long x = a.tv_sec - b.tv_sec;
if (x == 0L)
x = a.tv_nsec - b.tv_nsec;
return (x < 0L ? (-1) : x > 0L ? (1) : (0));
}
static inline void
evNowTime(struct timespec *res) {
struct timeval now;
if (gettimeofday(&now, NULL) < 0)
evConsTime(res, 0, 0);
else
TIMEVAL_TO_TIMESPEC (&now, res);
}
/* Options. Leave them on. */
/* #undef DEBUG */
#include "res_debug.h"
#define EXT(res) ((res)->_u._ext)
/* Forward. */
static int send_vc(res_state, const u_char *, int,
u_char **, int *, int *, int, u_char **);
static int send_dg(res_state, const u_char *, int,
u_char **, int *, int *, int,
int *, int *, u_char **);
#ifdef DEBUG
static void Aerror(const res_state, FILE *, const char *, int,
const struct sockaddr *);
static void Perror(const res_state, FILE *, const char *, int);
#endif
static int sock_eq(struct sockaddr_in6 *, struct sockaddr_in6 *);
/* Reachover. */
static void convaddr4to6(struct sockaddr_in6 *sa);
void res_pquery(const res_state, const u_char *, int, FILE *);
/* Public. */
/* int
* res_isourserver(ina)
* looks up "ina" in _res.ns_addr_list[]
* returns:
* 0 : not found
* >0 : found
* author:
* paul vixie, 29may94
*/
int
res_ourserver_p(const res_state statp, const struct sockaddr_in6 *inp)
{
int ns;
if (inp->sin6_family == AF_INET) {
struct sockaddr_in *in4p = (struct sockaddr_in *) inp;
in_port_t port = in4p->sin_port;
in_addr_t addr = in4p->sin_addr.s_addr;
for (ns = 0; ns < MAXNS; ns++) {
const struct sockaddr_in *srv =
(struct sockaddr_in *)EXT(statp).nsaddrs[ns];
if ((srv != NULL) && (srv->sin_family == AF_INET) &&
(srv->sin_port == port) &&
(srv->sin_addr.s_addr == INADDR_ANY ||
srv->sin_addr.s_addr == addr))
return (1);
}
} else if (inp->sin6_family == AF_INET6) {
for (ns = 0; ns < MAXNS; ns++) {
const struct sockaddr_in6 *srv = EXT(statp).nsaddrs[ns];
if ((srv != NULL) && (srv->sin6_family == AF_INET6) &&
(srv->sin6_port == inp->sin6_port) &&
!(memcmp(&srv->sin6_addr, &in6addr_any,
sizeof (struct in6_addr)) &&
memcmp(&srv->sin6_addr, &inp->sin6_addr,
sizeof (struct in6_addr))))
return (1);
}
}
return (0);
}
/* int
* res_nameinquery(name, type, class, buf, eom)
* look for (name,type,class) in the query section of packet (buf,eom)
* requires:
* buf + HFIXEDSZ <= eom
* returns:
* -1 : format error
* 0 : not found
* >0 : found
* author:
* paul vixie, 29may94
*/
int
res_nameinquery(const char *name, int type, int class,
const u_char *buf, const u_char *eom)
{
const u_char *cp = buf + HFIXEDSZ;
int qdcount = ntohs(((HEADER*)buf)->qdcount);
while (qdcount-- > 0) {
char tname[MAXDNAME+1];
int n, ttype, tclass;
n = dn_expand(buf, eom, cp, tname, sizeof tname);
if (n < 0)
return (-1);
cp += n;
if (cp + 2 * INT16SZ > eom)
return (-1);
NS_GET16(ttype, cp);
NS_GET16(tclass, cp);
if (ttype == type && tclass == class &&
ns_samename(tname, name) == 1)
return (1);
}
return (0);
}
libresolv_hidden_def (res_nameinquery)
/* int
* res_queriesmatch(buf1, eom1, buf2, eom2)
* is there a 1:1 mapping of (name,type,class)
* in (buf1,eom1) and (buf2,eom2)?
* returns:
* -1 : format error
* 0 : not a 1:1 mapping
* >0 : is a 1:1 mapping
* author:
* paul vixie, 29may94
*/
int
res_queriesmatch(const u_char *buf1, const u_char *eom1,
const u_char *buf2, const u_char *eom2)
{
if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
return (-1);
/*
* Only header section present in replies to
* dynamic update packets.
*/
if ((((HEADER *)buf1)->opcode == ns_o_update) &&
(((HEADER *)buf2)->opcode == ns_o_update))
return (1);
/* Note that we initially do not convert QDCOUNT to the host byte
order. We can compare it with the second buffer's QDCOUNT
value without doing this. */
int qdcount = ((HEADER*)buf1)->qdcount;
if (qdcount != ((HEADER*)buf2)->qdcount)
return (0);
qdcount = htons (qdcount);
const u_char *cp = buf1 + HFIXEDSZ;
while (qdcount-- > 0) {
char tname[MAXDNAME+1];
int n, ttype, tclass;
n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
if (n < 0)
return (-1);
cp += n;
if (cp + 2 * INT16SZ > eom1)
return (-1);
NS_GET16(ttype, cp);
NS_GET16(tclass, cp);
if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
return (0);
}
return (1);
}
libresolv_hidden_def (res_queriesmatch)
int
__libc_res_nsend(res_state statp, const u_char *buf, int buflen,
u_char *ans, int anssiz, u_char **ansp)
{
int gotsomewhere, terrno, try, v_circuit, resplen, ns, n;
if (statp->nscount == 0) {
__set_errno (ESRCH);
return (-1);
}
if (anssiz < HFIXEDSZ) {
__set_errno (EINVAL);
return (-1);
}
if ((statp->qhook || statp->rhook) && anssiz < MAXPACKET && ansp) {
u_char *buf = malloc (MAXPACKET);
if (buf == NULL)
return (-1);
memcpy (buf, ans, HFIXEDSZ);
*ansp = buf;
ans = buf;
anssiz = MAXPACKET;
}
DprintQ((statp->options & RES_DEBUG) || (statp->pfcode & RES_PRF_QUERY),
(stdout, ";; res_send()\n"), buf, buflen);
v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
gotsomewhere = 0;
terrno = ETIMEDOUT;
/*
* If the ns_addr_list in the resolver context has changed, then
* invalidate our cached copy and the associated timing data.
*/
if (EXT(statp).nsinit) {
int needclose = 0;
if (EXT(statp).nscount != statp->nscount)
needclose++;
else
for (ns = 0; ns < MAXNS; ns++) {
unsigned int map = EXT(statp).nsmap[ns];
if (map < MAXNS
&& !sock_eq((struct sockaddr_in6 *)
&statp->nsaddr_list[map],
EXT(statp).nsaddrs[ns]))
{
needclose++;
break;
}
}
if (needclose)
__res_iclose(statp, false);
}
/*
* Maybe initialize our private copy of the ns_addr_list.
*/
if (EXT(statp).nsinit == 0) {
unsigned char map[MAXNS];
memset (map, MAXNS, sizeof (map));
for (n = 0; n < MAXNS; n++) {
ns = EXT(statp).nsmap[n];
if (ns < statp->nscount)
map[ns] = n;
else if (ns < MAXNS) {
free(EXT(statp).nsaddrs[n]);
EXT(statp).nsaddrs[n] = NULL;
EXT(statp).nsmap[n] = MAXNS;
}
}
n = statp->nscount;
if (statp->nscount > EXT(statp).nscount)
for (n = EXT(statp).nscount, ns = 0;
n < statp->nscount; n++) {
while (ns < MAXNS
&& EXT(statp).nsmap[ns] != MAXNS)
ns++;
if (ns == MAXNS)
break;
EXT(statp).nsmap[ns] = n;
map[n] = ns++;
}
EXT(statp).nscount = n;
for (ns = 0; ns < EXT(statp).nscount; ns++) {
n = map[ns];
if (EXT(statp).nsaddrs[n] == NULL)
EXT(statp).nsaddrs[n] =
malloc(sizeof (struct sockaddr_in6));
if (EXT(statp).nsaddrs[n] != NULL) {
memset (mempcpy(EXT(statp).nsaddrs[n],
&statp->nsaddr_list[ns],
sizeof (struct sockaddr_in)),
'\0',
sizeof (struct sockaddr_in6)
- sizeof (struct sockaddr_in));
EXT(statp).nssocks[n] = -1;
n++;
}
}
EXT(statp).nsinit = 1;
}
/*
* Some resolvers want to even out the load on their nameservers.
* Note that RES_BLAST overrides RES_ROTATE.
*/
if ((statp->options & RES_ROTATE) != 0 &&
(statp->options & RES_BLAST) == 0) {
struct sockaddr_in6 *ina;
unsigned int map;
n = 0;
while (n < MAXNS && EXT(statp).nsmap[n] == MAXNS)
n++;
if (n < MAXNS) {
ina = EXT(statp).nsaddrs[n];
map = EXT(statp).nsmap[n];
for (;;) {
ns = n + 1;
while (ns < MAXNS
&& EXT(statp).nsmap[ns] == MAXNS)
ns++;
if (ns == MAXNS)
break;
EXT(statp).nsaddrs[n] = EXT(statp).nsaddrs[ns];
EXT(statp).nsmap[n] = EXT(statp).nsmap[ns];
n = ns;
}
EXT(statp).nsaddrs[n] = ina;
EXT(statp).nsmap[n] = map;
}
}
/*
* Send request, RETRY times, or until successful.
*/
for (try = 0; try < statp->retry; try++) {
for (ns = 0; ns < MAXNS; ns++)
{
struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
if (nsap == NULL)
goto next_ns;
same_ns:
if (statp->qhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
struct sockaddr_in *nsap4;
nsap4 = (struct sockaddr_in *) nsap;
act = (*statp->qhook)(&nsap4, &buf, &buflen,
ans, anssiz, &resplen);
nsap = (struct sockaddr_in6 *) nsap4;
switch (act) {
case res_goahead:
done = 1;
break;
case res_nextns:
__res_iclose(statp, false);
goto next_ns;
case res_done:
return (resplen);
case res_modified:
/* give the hook another try */
if (++loops < 42) /*doug adams*/
break;
/*FALLTHROUGH*/
case res_error:
/*FALLTHROUGH*/
default:
return (-1);
}
} while (!done);
}
#ifdef DEBUG
char tmpbuf[40];
#endif
Dprint(statp->options & RES_DEBUG,
(stdout, ";; Querying server (# %d) address = %s\n",
ns + 1, inet_ntop(AF_INET6, &nsap->sin6_addr,
tmpbuf, sizeof (tmpbuf))));
if (v_circuit) {
/* Use VC; at most one attempt per server. */
try = statp->retry;
n = send_vc(statp, buf, buflen, &ans, &anssiz, &terrno,
ns, ansp);
if (n < 0)
return (-1);
if (n == 0)
goto next_ns;
resplen = n;
} else {
/* Use datagrams. */
n = send_dg(statp, buf, buflen, &ans, &anssiz, &terrno,
ns, &v_circuit, &gotsomewhere, ansp);
if (n < 0)
return (-1);
if (n == 0)
goto next_ns;
if (v_circuit)
goto same_ns;
resplen = n;
}
Dprint((statp->options & RES_DEBUG) ||
((statp->pfcode & RES_PRF_REPLY) &&
(statp->pfcode & RES_PRF_HEAD1)),
(stdout, ";; got answer:\n"));
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, "%s", ""),
ans, (resplen > anssiz) ? anssiz : resplen);
/*
* If we have temporarily opened a virtual circuit,
* or if we haven't been asked to keep a socket open,
* close the socket.
*/
if ((v_circuit && (statp->options & RES_USEVC) == 0) ||
(statp->options & RES_STAYOPEN) == 0) {
__res_iclose(statp, false);
}
if (statp->rhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*statp->rhook)((struct sockaddr_in *)
nsap, buf, buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
case res_done:
done = 1;
break;
case res_nextns:
__res_iclose(statp, false);
goto next_ns;
case res_modified:
/* give the hook another try */
if (++loops < 42) /*doug adams*/
break;
/*FALLTHROUGH*/
case res_error:
/*FALLTHROUGH*/
default:
return (-1);
}
} while (!done);
}
return (resplen);
next_ns: ;
} /*foreach ns*/
} /*foreach retry*/
__res_iclose(statp, false);
if (!v_circuit) {
if (!gotsomewhere)
__set_errno (ECONNREFUSED); /* no nameservers found */
else
__set_errno (ETIMEDOUT); /* no answer obtained */
} else
__set_errno (terrno);
return (-1);
}
int
res_nsend(res_state statp,
const u_char *buf, int buflen, u_char *ans, int anssiz)
{
return __libc_res_nsend(statp, buf, buflen, ans, anssiz, NULL);
}
libresolv_hidden_def (res_nsend)
/* Private */
static int
send_vc(res_state statp,
const u_char *buf, int buflen, u_char **ansp, int *anssizp,
int *terrno, int ns, u_char **anscp)
{
const HEADER *hp = (HEADER *) buf;
u_char *ans = *ansp;
int anssiz = *anssizp;
HEADER *anhp = (HEADER *) ans;
struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
int truncating, connreset, resplen, n;
struct iovec iov[2];
u_short len;
u_char *cp;
connreset = 0;
same_ns:
truncating = 0;
/* Are we still talking to whom we want to talk to? */
if (statp->_vcsock >= 0 && (statp->_flags & RES_F_VC) != 0) {
struct sockaddr_in6 peer;
socklen_t size = sizeof peer;
if (getpeername(statp->_vcsock,
(struct sockaddr *)&peer, &size) < 0 ||
!sock_eq(&peer, nsap)) {
__res_iclose(statp, false);
statp->_flags &= ~RES_F_VC;
}
}
if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
if (statp->_vcsock >= 0)
__res_iclose(statp, false);
statp->_vcsock = socket(nsap->sin6_family, SOCK_STREAM, 0);
if (statp->_vcsock < 0) {
*terrno = errno;
Perror(statp, stderr, "socket(vc)", errno);
return (-1);
}
__set_errno (0);
if (connect(statp->_vcsock, (struct sockaddr *)nsap,
nsap->sin6_family == AF_INET
? sizeof (struct sockaddr_in)
: sizeof (struct sockaddr_in6)) < 0) {
*terrno = errno;
Aerror(statp, stderr, "connect/vc", errno,
(struct sockaddr *) nsap);
__res_iclose(statp, false);
return (0);
}
statp->_flags |= RES_F_VC;
}
/*
* Send length & message
*/
ns_put16((u_short)buflen, (u_char*)&len);
evConsIovec(&len, INT16SZ, &iov[0]);
evConsIovec((void*)buf, buflen, &iov[1]);
if (TEMP_FAILURE_RETRY (writev(statp->_vcsock, iov, 2))
!= (INT16SZ + buflen)) {
*terrno = errno;
Perror(statp, stderr, "write failed", errno);
__res_iclose(statp, false);
return (0);
}
/*
* Receive length & response
*/
read_len:
cp = ans;
len = INT16SZ;
while ((n = TEMP_FAILURE_RETRY (read(statp->_vcsock, (char *)cp,
(int)len))) > 0) {
cp += n;
if ((len -= n) <= 0)
break;
}
if (n <= 0) {
*terrno = errno;
Perror(statp, stderr, "read failed", errno);
__res_iclose(statp, false);
/*
* A long running process might get its TCP
* connection reset if the remote server was
* restarted. Requery the server instead of
* trying a new one. When there is only one
* server, this means that a query might work
* instead of failing. We only allow one reset
* per query to prevent looping.
*/
if (*terrno == ECONNRESET && !connreset) {
connreset = 1;
goto same_ns;
}
return (0);
}
resplen = ns_get16(ans);
if (resplen > anssiz) {
if (anscp) {
ans = malloc (MAXPACKET);
if (ans == NULL) {
*terrno = ENOMEM;
__res_iclose(statp, false);
return (0);
}
anssiz = MAXPACKET;
*anssizp = MAXPACKET;
*ansp = ans;
*anscp = ans;
anhp = (HEADER *) ans;
len = resplen;
} else {
Dprint(statp->options & RES_DEBUG,
(stdout, ";; response truncated\n")
);
truncating = 1;
len = anssiz;
}
} else
len = resplen;
if (len < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; undersized: %d\n", len));
*terrno = EMSGSIZE;
__res_iclose(statp, false);
return (0);
}
cp = ans;
while (len != 0 && (n = read(statp->_vcsock, (char *)cp, (int)len)) > 0){
cp += n;
len -= n;
}
if (n <= 0) {
*terrno = errno;
Perror(statp, stderr, "read(vc)", errno);
__res_iclose(statp, false);
return (0);
}
if (truncating) {
/*
* Flush rest of answer so connection stays in synch.
*/
anhp->tc = 1;
len = resplen - anssiz;
while (len != 0) {
char junk[PACKETSZ];
n = read(statp->_vcsock, junk,
(len > sizeof junk) ? sizeof junk : len);
if (n > 0)
len -= n;
else
break;
}
}
/*
* If the calling applicating has bailed out of
* a previous call and failed to arrange to have
* the circuit closed or the server has got
* itself confused, then drop the packet and
* wait for the correct one.
*/
if (hp->id != anhp->id) {
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; old answer (unexpected):\n"),
ans, (resplen > anssiz) ? anssiz: resplen);
goto read_len;
}
/*
* All is well, or the error is fatal. Signal that the
* next nameserver ought not be tried.
*/
return (resplen);
}
static int
send_dg(res_state statp,
const u_char *buf, int buflen, u_char **ansp, int *anssizp,
int *terrno, int ns, int *v_circuit, int *gotsomewhere, u_char **anscp)
{
const HEADER *hp = (HEADER *) buf;
u_char *ans = *ansp;
int anssiz = *anssizp;
HEADER *anhp = (HEADER *) ans;
struct sockaddr_in6 *nsap = EXT(statp).nsaddrs[ns];
struct timespec now, timeout, finish;
struct pollfd pfd[1];
int ptimeout;
struct sockaddr_in6 from;
socklen_t fromlen;
int resplen, seconds, n;
if (EXT(statp).nssocks[ns] == -1) {
/* only try IPv6 if IPv6 NS and if not failed before */
if ((EXT(statp).nscount6 > 0) && !statp->ipv6_unavail) {
EXT(statp).nssocks[ns] =
socket(PF_INET6, SOCK_DGRAM, 0);
if (EXT(statp).nssocks[ns] < 0)
statp->ipv6_unavail = errno == EAFNOSUPPORT;
/* If IPv6 socket and nsap is IPv4, make it
IPv4-mapped */
else if (nsap->sin6_family == AF_INET)
convaddr4to6(nsap);
}
if (EXT(statp).nssocks[ns] < 0)
EXT(statp).nssocks[ns] = socket(PF_INET, SOCK_DGRAM, 0);
if (EXT(statp).nssocks[ns] < 0) {
*terrno = errno;
Perror(statp, stderr, "socket(dg)", errno);
return (-1);
}
/*
* On a 4.3BSD+ machine (client and server,
* actually), sending to a nameserver datagram
* port with no nameserver will cause an
* ICMP port unreachable message to be returned.
* If our datagram socket is "connected" to the
* server, we get an ECONNREFUSED error on the next
* socket operation, and select returns if the
* error message is received. We can thus detect
* the absence of a nameserver without timing out.
*/
if (connect(EXT(statp).nssocks[ns], (struct sockaddr *)nsap,
sizeof *nsap) < 0) {
Aerror(statp, stderr, "connect(dg)", errno,
(struct sockaddr *) nsap);
__res_iclose(statp, false);
return (0);
}
/* Make socket non-blocking. */
int fl = __fcntl (EXT(statp).nssocks[ns], F_GETFL);
if (fl != -1)
__fcntl (EXT(statp).nssocks[ns], F_SETFL,
fl | O_NONBLOCK);
Dprint(statp->options & RES_DEBUG,
(stdout, ";; new DG socket\n"))
}
/*
* Compute time for the total operation.
*/
seconds = (statp->retrans << ns);
if (ns > 0)
seconds /= statp->nscount;
if (seconds <= 0)
seconds = 1;
evNowTime(&now);
evConsTime(&timeout, seconds, 0);
evAddTime(&finish, &now, &timeout);
int need_recompute = 0;
int nwritten = 0;
pfd[0].fd = EXT(statp).nssocks[ns];
pfd[0].events = POLLOUT;
wait:
if (need_recompute) {
recompute_resend:
evNowTime(&now);
if (evCmpTime(finish, now) <= 0) {
poll_err_out:
Perror(statp, stderr, "poll", errno);
err_out:
__res_iclose(statp, false);
return (0);
}
evSubTime(&timeout, &finish, &now);
}
/* Convert struct timespec in milliseconds. */
ptimeout = timeout.tv_sec * 1000 + timeout.tv_nsec / 1000000;
n = 0;
if (nwritten == 0)
n = __poll (pfd, 1, 0);
if (__builtin_expect (n == 0, 0)) {
n = __poll (pfd, 1, ptimeout);
need_recompute = 1;
}
if (n == 0) {
Dprint(statp->options & RES_DEBUG, (stdout,
";; timeout sending\n"));
*gotsomewhere = 1;
return (0);
}
if (n < 0) {
if (errno == EINTR)
goto recompute_resend;
goto poll_err_out;
}
__set_errno (0);
if (pfd[0].revents & POLLOUT) {
if (send (pfd[0].fd, buf, buflen, MSG_NOSIGNAL) != buflen) {
if (errno == EINTR || errno == EAGAIN)
goto recompute_resend;
Perror(statp, stderr, "send", errno);
goto err_out;
}
pfd[0].events = POLLIN;
++nwritten;
goto wait;
} else if (pfd[0].revents & POLLIN) {
fromlen = sizeof(struct sockaddr_in6);
if (anssiz < MAXPACKET
&& anscp
&& (ioctl (pfd[0].fd, FIONREAD, &resplen) < 0
|| anssiz < resplen)) {
ans = malloc (MAXPACKET);
if (ans == NULL)
ans = *ansp;
else {
anssiz = MAXPACKET;
*anssizp = MAXPACKET;
*ansp = ans;
*anscp = ans;
anhp = (HEADER *) ans;
}
}
resplen = recvfrom(pfd[0].fd, (char*)ans, anssiz,0,
(struct sockaddr *)&from, &fromlen);
if (resplen <= 0) {
if (errno == EINTR || errno == EAGAIN) {
need_recompute = 1;
goto wait;
}
Perror(statp, stderr, "recvfrom", errno);
goto err_out;
}
*gotsomewhere = 1;
if (resplen < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; undersized: %d\n",
resplen));
*terrno = EMSGSIZE;
goto err_out;
}
if (hp->id != anhp->id) {
/*
* response from old query, ignore it.
* XXX - potential security hazard could
* be detected here.
*/
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; old answer:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto wait;
}
if (!(statp->options & RES_INSECURE1) &&
!res_ourserver_p(statp, &from)) {
/*
* response from wrong server? ignore it.
* XXX - potential security hazard could
* be detected here.
*/
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; not our server:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto wait;
}
#ifdef RES_USE_EDNS0
if (anhp->rcode == FORMERR
&& (statp->options & RES_USE_EDNS0) != 0U) {
/*
* Do not retry if the server do not understand
* EDNS0. The case has to be captured here, as
* FORMERR packet do not carry query section, hence
* res_queriesmatch() returns 0.
*/
DprintQ(statp->options & RES_DEBUG,
(stdout,
"server rejected query with EDNS0:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
/* record the error */
statp->_flags |= RES_F_EDNS0ERR;
goto err_out;
}
#endif
if (!(statp->options & RES_INSECURE2) &&
!res_queriesmatch(buf, buf + buflen,
ans, ans + anssiz)) {
/*
* response contains wrong query? ignore it.
* XXX - potential security hazard could
* be detected here.
*/
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; wrong query name:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto wait;
}
if (anhp->rcode == SERVFAIL ||
anhp->rcode == NOTIMP ||
anhp->rcode == REFUSED) {
DprintQ(statp->options & RES_DEBUG,
(stdout, "server rejected query:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
next_ns:
__res_iclose(statp, false);
/* don't retry if called from dig */
if (!statp->pfcode)
return (0);
}
if (anhp->rcode == NOERROR && anhp->ancount == 0
&& anhp->aa == 0 && anhp->ra == 0 && anhp->arcount == 0) {
DprintQ(statp->options & RES_DEBUG,
(stdout, "referred query:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto next_ns;
}
if (!(statp->options & RES_IGNTC) && anhp->tc) {
/*
* To get the rest of answer,
* use TCP with same server.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; truncated answer\n"));
*v_circuit = 1;
__res_iclose(statp, false);
return (1);
}
/*
* All is well, or the error is fatal. Signal that the
* next nameserver ought not be tried.
*/
return (resplen);
} else if (pfd[0].revents & (POLLERR | POLLHUP | POLLNVAL)) {
/* Something went wrong. We can stop trying. */
goto err_out;
}
else {
/* poll should not have returned > 0 in this case. */
abort ();
}
}
#ifdef DEBUG
static void
Aerror(const res_state statp, FILE *file, const char *string, int error,
const struct sockaddr *address)
{
int save = errno;
if ((statp->options & RES_DEBUG) != 0) {
char tmp[sizeof "xxxx.xxxx.xxxx.255.255.255.255"];
fprintf(file, "res_send: %s ([%s].%u): %s\n",
string,
(address->sa_family == AF_INET
? inet_ntop(address->sa_family,
&((const struct sockaddr_in *) address)->sin_addr,
tmp, sizeof tmp)
: inet_ntop(address->sa_family,
&((const struct sockaddr_in6 *) address)->sin6_addr,
tmp, sizeof tmp)),
(address->sa_family == AF_INET
? ntohs(((struct sockaddr_in *) address)->sin_port)
: address->sa_family == AF_INET6
? ntohs(((struct sockaddr_in6 *) address)->sin6_port)
: 0),
strerror(error));
}
__set_errno (save);
}
static void
Perror(const res_state statp, FILE *file, const char *string, int error) {
int save = errno;
if ((statp->options & RES_DEBUG) != 0)
fprintf(file, "res_send: %s: %s\n",
string, strerror(error));
__set_errno (save);
}
#endif
static int
sock_eq(struct sockaddr_in6 *a1, struct sockaddr_in6 *a2) {
if (a1->sin6_family == a2->sin6_family) {
if (a1->sin6_family == AF_INET)
return ((((struct sockaddr_in *)a1)->sin_port ==
((struct sockaddr_in *)a2)->sin_port) &&
(((struct sockaddr_in *)a1)->sin_addr.s_addr ==
((struct sockaddr_in *)a2)->sin_addr.s_addr));
else
return ((a1->sin6_port == a2->sin6_port) &&
!memcmp(&a1->sin6_addr, &a2->sin6_addr,
sizeof (struct in6_addr)));
}
if (a1->sin6_family == AF_INET) {
struct sockaddr_in6 *sap = a1;
a1 = a2;
a2 = sap;
} /* assumes that AF_INET and AF_INET6 are the only possibilities */
return ((a1->sin6_port == ((struct sockaddr_in *)a2)->sin_port) &&
IN6_IS_ADDR_V4MAPPED(&a1->sin6_addr) &&
(a1->sin6_addr.s6_addr32[3] ==
((struct sockaddr_in *)a2)->sin_addr.s_addr));
}
/*
* Converts IPv4 family, address and port to
* IPv6 family, IPv4-mapped IPv6 address and port.
*/
static void
convaddr4to6(struct sockaddr_in6 *sa)
{
struct sockaddr_in *sa4p = (struct sockaddr_in *) sa;
in_port_t port = sa4p->sin_port;
in_addr_t addr = sa4p->sin_addr.s_addr;
sa->sin6_family = AF_INET6;
sa->sin6_port = port;
sa->sin6_addr.s6_addr32[0] = 0;
sa->sin6_addr.s6_addr32[1] = 0;
sa->sin6_addr.s6_addr32[2] = htonl(0xFFFF);
sa->sin6_addr.s6_addr32[3] = addr;
}
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