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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[] = "$Id$";
#endif /* LIBC_SCCS and not lint */
/*
* Send query to name server and wait for reply.
*/
#include <sys/types.h>
#include <sys/param.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <errno.h>
#include <netdb.h>
#include <resolv.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/poll.h>
/* Options. Leave them on. */
/* #undef DEBUG */
#include "res_debug.h"
#ifdef NEED_PSELECT
static int pselect(int, void *, void *, void *,
struct timespec *,
const sigset_t *);
#endif
#define CHECK_SRVR_ADDR
/* From bind lib/isc/ev_timers.c: */
#define BILLION 1000000000
static struct timespec
evTimeSpec(struct timeval tv) {
struct timespec ts;
ts.tv_sec = tv.tv_sec;
ts.tv_nsec = tv.tv_usec * 1000;
return (ts);
}
static struct timespec
evConsTime(time_t sec, long nsec) {
struct timespec x;
x.tv_sec = sec;
x.tv_nsec = nsec;
return (x);
}
static struct timespec
evAddTime(struct timespec addend1, struct timespec addend2) {
struct timespec x;
x.tv_sec = addend1.tv_sec + addend2.tv_sec;
x.tv_nsec = addend1.tv_nsec + addend2.tv_nsec;
if (x.tv_nsec >= BILLION) {
x.tv_sec++;
x.tv_nsec -= BILLION;
}
return (x);
}
static struct timespec
evSubTime(struct timespec minuend, struct timespec subtrahend) {
struct timespec x;
x.tv_sec = minuend.tv_sec - subtrahend.tv_sec;
if (minuend.tv_nsec >= subtrahend.tv_nsec)
x.tv_nsec = minuend.tv_nsec - subtrahend.tv_nsec;
else {
x.tv_nsec = BILLION - subtrahend.tv_nsec + minuend.tv_nsec;
x.tv_sec--;
}
return (x);
}
static 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 struct timespec
evNowTime() {
struct timeval now;
if (gettimeofday(&now, NULL) < 0)
return (evConsTime(0, 0));
return (evTimeSpec(now));
}
/* End of code from bind lib/isc/ev_timers.c. */
#ifdef DEBUG
static void
Aerror(const res_state statp, FILE *file, const char *string, int error,
struct sockaddr_in address)
{
int save = errno;
if ((statp->options & RES_DEBUG) != 0) {
char tmp[sizeof "255.255.255.255"];
fprintf(file, "res_send: %s ([%s].%u): %s\n",
string,
inet_ntop(address.sin_family, &address.sin_addr,
tmp, sizeof tmp),
ntohs(address.sin_port),
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 cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2);
void res_pquery(const res_state, const u_char *, int, FILE *);
/* 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_in *inp) {
struct sockaddr_in ina;
int ns;
ina = *inp;
for (ns = 0; ns < statp->nscount; ns++) {
const struct sockaddr_in *srv = &statp->nsaddr_list[ns];
if (srv->sin_family == ina.sin_family &&
srv->sin_port == ina.sin_port &&
(srv->sin_addr.s_addr == INADDR_ANY ||
srv->sin_addr.s_addr == ina.sin_addr.s_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);
ttype = ns_get16(cp); cp += INT16SZ;
tclass = ns_get16(cp); cp += INT16SZ;
if (ttype == type && tclass == class &&
ns_samename(tname, name) == 1)
return (1);
}
return (0);
}
/* 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)
{
const u_char *cp = buf1 + HFIXEDSZ;
int qdcount = ntohs(((HEADER*)buf1)->qdcount);
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);
if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
return (0);
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);
ttype = ns_get16(cp); cp += INT16SZ;
tclass = ns_get16(cp); cp += INT16SZ;
if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
return (0);
}
return (1);
}
int
res_nsend(res_state statp,
const u_char *buf, int buflen, u_char *ans, int anssiz)
{
HEADER *hp = (HEADER *) buf;
HEADER *anhp = (HEADER *) ans;
int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns, n;
u_int badns; /* XXX NSMAX can't exceed #/bits in this variable */
static int highestFD = FD_SETSIZE - 1;
if (anssiz < HFIXEDSZ) {
__set_errno (EINVAL);
return (-1);
}
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;
connreset = 0;
terrno = ETIMEDOUT;
badns = 0;
/*
* Some callers want to even out the load on their resolver list.
*/
if (statp->nscount > 0 && (statp->options & RES_ROTATE) != 0) {
struct sockaddr_in ina;
int lastns = statp->nscount - 1;
ina = statp->nsaddr_list[0];
for (ns = 0; ns < lastns; ns++)
statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
statp->nsaddr_list[lastns] = ina;
}
/*
* Send request, RETRY times, or until successful
*/
for (try = 0; try < statp->retry; try++) {
for (ns = 0; ns < statp->nscount; ns++) {
struct sockaddr_in *nsap = &statp->nsaddr_list[ns];
same_ns:
if (badns & (1 << ns)) {
res_nclose(statp);
goto next_ns;
}
if (statp->qhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*statp->qhook)(&nsap, &buf, &buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
done = 1;
break;
case res_nextns:
res_nclose(statp);
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);
}
Dprint(statp->options & RES_DEBUG,
(stdout, ";; Querying server (# %d) address = %s\n",
ns + 1, inet_ntoa(nsap->sin_addr)));
if (v_circuit) {
int truncated;
struct iovec iov[2];
u_short len;
u_char *cp;
/* Use VC; at most one attempt per server. */
try = statp->retry;
truncated = 0;
/* Are we still talking to whom we want to talk to? */
if (statp->_sock >= 0 &&
(statp->_flags & RES_F_VC) != 0) {
struct sockaddr_in peer;
int size = sizeof(peer);
if (getpeername(statp->_sock,
(struct sockaddr *)&peer,
&size) < 0) {
res_nclose(statp);
statp->_flags &= ~RES_F_VC;
} else if (!cmpsock(&peer, nsap)) {
res_nclose(statp);
statp->_flags &= ~RES_F_VC;
}
}
if (statp->_sock < 0 ||
(statp->_flags & RES_F_VC) == 0) {
if (statp->_sock >= 0)
res_nclose(statp);
statp->_sock = socket(PF_INET,
SOCK_STREAM, 0);
if (statp->_sock < 0 ||
statp->_sock > highestFD) {
terrno = errno;
Perror(statp, stderr,
"socket(vc)", errno);
return (-1);
}
__set_errno (0);
if (connect(statp->_sock,
(struct sockaddr *)nsap,
sizeof *nsap) < 0) {
terrno = errno;
Aerror(statp, stderr, "connect/vc",
errno, *nsap);
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
statp->_flags |= RES_F_VC;
}
/*
* Send length & message
*/
putshort((u_short)buflen, (u_char*)&len);
iov[0].iov_base = (caddr_t)&len;
iov[0].iov_len = INT16SZ;
iov[1].iov_base = (caddr_t)buf;
iov[1].iov_len = buflen;
if (writev(statp->_sock, iov, 2) !=
(INT16SZ + buflen)) {
terrno = errno;
Perror(statp, stderr, "write failed", errno);
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
/*
* Receive length & response
*/
read_len:
cp = ans;
len = INT16SZ;
while ((n = read(statp->_sock,
(char *)cp, (int)len)) > 0) {
cp += n;
if ((len -= n) <= 0)
break;
}
if (n <= 0) {
terrno = errno;
Perror(statp, stderr, "read failed", errno);
res_nclose(statp);
/*
* 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;
res_nclose(statp);
goto same_ns;
}
res_nclose(statp);
goto next_ns;
}
resplen = ns_get16(ans);
if (resplen > anssiz) {
Dprint(statp->options & RES_DEBUG,
(stdout, ";; response truncated\n")
);
truncated = 1;
len = anssiz;
} else
len = resplen;
if (len < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; undersized: %d\n", len));
terrno = EMSGSIZE;
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
cp = ans;
while (len != 0 &&
(n = read(statp->_sock, (char *)cp, (int)len))
> 0) {
cp += n;
len -= n;
}
if (n <= 0) {
terrno = errno;
Perror(statp, stderr, "read(vc)", errno);
res_nclose(statp);
goto next_ns;
}
if (truncated) {
/*
* Flush rest of answer
* so connection stays in synch.
*/
anhp->tc = 1;
len = resplen - anssiz;
while (len != 0) {
char junk[PACKETSZ];
n = ((size_t)len > sizeof(junk)
? sizeof(junk)
: len);
n = read(statp->_sock, junk, n);
if (n > 0)
len -= n;
else
break;
}
}
/*
* 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. Anyway 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;
}
} else {
/*
* Use datagrams.
*/
struct timespec start, timeout, finish;
#ifdef _LIBC
struct pollfd pfd[1];
int ptimeout;
#else
fd_set dsmask;
#endif
struct sockaddr_in from;
int fromlen, seconds;
if (statp->_sock < 0 ||
(statp->_flags & RES_F_VC) != 0) {
if ((statp->_flags & RES_F_VC) != 0)
res_nclose(statp);
statp->_sock = socket(PF_INET, SOCK_DGRAM, 0);
if (statp->_sock < 0 ||
statp->_sock > highestFD) {
#ifndef CAN_RECONNECT
bad_dg_sock:
#endif
terrno = errno;
Perror(statp, stderr,
"socket(dg)", errno);
return (-1);
}
statp->_flags &= ~RES_F_CONN;
}
#ifndef CANNOT_CONNECT_DGRAM
/*
* 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 we have sent queries to at least two servers,
* however, we don't want to remain connected,
* as we wish to receive answers from the first
* server to respond.
*/
if (statp->nscount == 1 || (try == 0 && ns == 0)) {
/*
* Connect only if we are sure we won't
* receive a response from another server.
*/
if ((statp->_flags & RES_F_CONN) == 0) {
if (connect(statp->_sock,
(struct sockaddr *)nsap,
sizeof *nsap) < 0) {
Aerror(statp, stderr,
"connect(dg)",
errno, *nsap);
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
statp->_flags |= RES_F_CONN;
}
if (send(statp->_sock, (char*)buf, buflen, 0)
!= buflen) {
Perror(statp, stderr, "send", errno);
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
} else {
/*
* Disconnect if we want to listen
* for responses from more than one server.
*/
if ((statp->_flags & RES_F_CONN) != 0) {
#ifdef CAN_RECONNECT
struct sockaddr_in no_addr;
no_addr.sin_family = AF_INET;
no_addr.sin_addr.s_addr = INADDR_ANY;
no_addr.sin_port = 0;
(void) connect(statp->_sock,
(struct sockaddr *)
&no_addr,
sizeof no_addr);
#else
struct sockaddr_in local_addr;
int len, result, s1;
len = sizeof(local_addr);
s1 = socket(PF_INET, SOCK_DGRAM, 0);
result = getsockname(statp->_sock,
(struct sockaddr *)&local_addr,
&len);
if (s1 < 0)
goto bad_dg_sock;
(void) dup2(s1, statp->_sock);
(void) close(s1);
if (result == 0) {
/*
* Attempt to rebind to old
* port. Note connected socket
* has an sin_addr set.
*/
local_addr.sin_addr.s_addr =
htonl(0);
(void)bind(statp->_sock,
(struct sockaddr *)
&local_addr, len);
}
Dprint(statp->options & RES_DEBUG,
(stdout, ";; new DG socket\n"))
#endif /* CAN_RECONNECT */
statp->_flags &= ~RES_F_CONN;
__set_errno (0);
}
#endif /* !CANNOT_CONNECT_DGRAM */
if (sendto(statp->_sock,
(char*)buf, buflen, 0,
(struct sockaddr *)nsap,
sizeof *nsap)
!= buflen) {
Aerror(statp, stderr, "sendto", errno, *nsap);
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
#ifndef CANNOT_CONNECT_DGRAM
}
#endif /* !CANNOT_CONNECT_DGRAM */
if (statp->_sock < 0 || statp->_sock > highestFD) {
Perror(statp, stderr,
"fd out-of-bounds", EMFILE);
res_nclose(statp);
goto next_ns;
}
/*
* Wait for reply
*/
seconds = (statp->retrans << try);
if (try > 0)
seconds /= statp->nscount;
if (seconds <= 0)
seconds = 1;
start = evNowTime();
timeout = evConsTime(seconds, 0);
finish = evAddTime(start, timeout);
wait:
#ifdef _LIBC
/* Convert struct timespec in milliseconds. */
ptimeout = timeout.tv_sec * 1000
+ timeout.tv_nsec / 1000000;
pfd[0].fd = statp->_sock;
pfd[0].events = POLLIN;
n = __poll (pfd, 1, ptimeout);
#else
FD_ZERO(&dsmask);
FD_SET(statp->_sock, &dsmask);
n = pselect(statp->_sock + 1,
&dsmask, NULL, NULL,
&timeout, NULL);
#endif
if (n == 0) {
Dprint(statp->options & RES_DEBUG,
(stdout, ";; timeout\n"));
gotsomewhere = 1;
goto next_ns;
}
if (n < 0) {
if (errno == EINTR) {
struct timespec now;
now = evNowTime();
if (evCmpTime(finish, now) >= 0) {
timeout = evSubTime(finish,
now);
goto wait;
}
}
#ifdef _LIBC
Perror(statp, stderr, "poll", errno);
#else
Perror(statp, stderr, "select", errno);
#endif
res_nclose(statp);
goto next_ns;
}
__set_errno (0);
fromlen = sizeof(struct sockaddr_in);
resplen = recvfrom(statp->_sock, (char*)ans, anssiz,0,
(struct sockaddr *)&from, &fromlen);
if (resplen <= 0) {
Perror(statp, stderr, "recvfrom", errno);
res_nclose(statp);
goto next_ns;
}
gotsomewhere = 1;
if (resplen < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; undersized: %d\n",
resplen));
terrno = EMSGSIZE;
badns |= (1 << ns);
res_nclose(statp);
goto next_ns;
}
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;
}
#ifdef CHECK_SRVR_ADDR
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;
}
#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);
badns |= (1 << ns);
res_nclose(statp);
/* don't retry if called from dig */
if (!statp->pfcode)
goto next_ns;
}
if (!(statp->options & RES_IGNTC) && anhp->tc) {
/*
* get rest of answer;
* use TCP with same server.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; truncated answer\n"));
v_circuit = 1;
res_nclose(statp);
goto same_ns;
}
} /*if vc/dg*/
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, ""),
ans, (resplen>anssiz)?anssiz:resplen);
/*
* If using virtual circuits, we assume that the first server
* is preferred over the rest (i.e. it is on the local
* machine) and only keep that one open.
* 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) || ns != 0)) ||
!(statp->options & RES_STAYOPEN)) {
res_nclose(statp);
}
if (statp->rhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*statp->rhook)(nsap, buf, buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
case res_done:
done = 1;
break;
case res_nextns:
res_nclose(statp);
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_nclose(statp);
if (!v_circuit) {
if (!gotsomewhere)
__set_errno (ECONNREFUSED); /* no nameservers found */
else
__set_errno (ETIMEDOUT); /* no answer obtained */
} else
__set_errno (terrno);
return (-1);
}
/*
* This routine is for closing the socket if a virtual circuit is used and
* the program wants to close it. This provides support for endhostent()
* which expects to close the socket.
*
* This routine is not expected to be user visible.
*/
void
res_nclose(res_state statp) {
if (statp->_sock >= 0) {
(void) close(statp->_sock);
statp->_sock = -1;
statp->_flags &= ~(RES_F_VC | RES_F_CONN);
}
}
/* Private */
static int
cmpsock(struct sockaddr_in *a1, struct sockaddr_in *a2) {
return ((a1->sin_family == a2->sin_family) &&
(a1->sin_port == a2->sin_port) &&
(a1->sin_addr.s_addr == a2->sin_addr.s_addr));
}
#ifdef NEED_PSELECT
/* XXX needs to move to the porting library. */
static int
pselect(int nfds, void *rfds, void *wfds, void *efds,
struct timespec *tsp,
const sigset_t *sigmask)
{
struct timeval tv, *tvp;
sigset_t sigs;
int n;
if (tsp) {
tvp = &tv;
tv = evTimeVal(*tsp);
} else
tvp = NULL;
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, &sigs);
n = select(nfds, rfds, wfds, efds, tvp);
if (sigmask)
sigprocmask(SIG_SETMASK, &sigs, NULL);
if (tsp)
*tsp = evTimeSpec(tv);
return (n);
}
#endif
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