/* $NetBSD: res_send.c,v 1.1.1.2 2012/09/09 16:08:10 christos Exp $ */
/*
* Portions Copyright (C) 2004-2009 Internet Systems Consortium, Inc. ("ISC")
* Portions Copyright (C) 1996-2003 Internet Software Consortium.
*
* Permission to use, copy, modify, and/or 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 ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC 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.
*/
/*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
static const char rcsid[] = "Id: res_send.c,v 1.22 2009/01/22 23:49:23 tbox Exp ";
#endif /* LIBC_SCCS and not lint */
/*! \file
* \brief
* Send query to name server and wait for reply.
*/
#include "port_before.h"
#include "fd_setsize.h"
#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 <isc/eventlib.h>
#include "port_after.h"
#ifdef USE_POLL
#ifdef HAVE_STROPTS_H
#include <stropts.h>
#endif
#include <poll.h>
#endif /* USE_POLL */
/* Options. Leave them on. */
#define DEBUG
#include "res_debug.h"
#include "res_private.h"
#define EXT(res) ((res)->_u._ext)
#ifndef USE_POLL
static const int highestFD = FD_SETSIZE - 1;
#else
static int highestFD = 0;
#endif
/* Forward. */
static int get_salen __P((const struct sockaddr *));
static struct sockaddr * get_nsaddr __P((res_state, size_t));
static int send_vc(res_state, const u_char *, int,
u_char *, int, int *, int);
static int send_dg(res_state, const u_char *, int,
u_char *, int, int *, int, int,
int *, int *);
static void Aerror(const res_state, FILE *, const char *, int,
const struct sockaddr *, int);
static void Perror(const res_state, FILE *, const char *, int);
static int sock_eq(struct sockaddr *, struct sockaddr *);
#if defined(NEED_PSELECT) && !defined(USE_POLL)
static int pselect(int, void *, void *, void *,
struct timespec *,
const sigset_t *);
#endif
void res_pquery(const res_state, const u_char *, int, FILE *);
static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
/* Public. */
/*%
* looks up "ina" in _res.ns_addr_list[]
*
* returns:
*\li 0 : not found
*\li >0 : found
*
* author:
*\li paul vixie, 29may94
*/
int
res_ourserver_p(const res_state statp, const struct sockaddr *sa) {
const struct sockaddr_in *inp, *srv;
const struct sockaddr_in6 *in6p, *srv6;
int ns;
switch (sa->sa_family) {
case AF_INET:
inp = (const struct sockaddr_in *)sa;
for (ns = 0; ns < statp->nscount; ns++) {
srv = (struct sockaddr_in *)get_nsaddr(statp, ns);
if (srv->sin_family == inp->sin_family &&
srv->sin_port == inp->sin_port &&
(srv->sin_addr.s_addr == INADDR_ANY ||
srv->sin_addr.s_addr == inp->sin_addr.s_addr))
return (1);
}
break;
case AF_INET6:
if (EXT(statp).ext == NULL)
break;
in6p = (const struct sockaddr_in6 *)sa;
for (ns = 0; ns < statp->nscount; ns++) {
srv6 = (struct sockaddr_in6 *)get_nsaddr(statp, ns);
if (srv6->sin6_family == in6p->sin6_family &&
srv6->sin6_port == in6p->sin6_port &&
#ifdef HAVE_SIN6_SCOPE_ID
(srv6->sin6_scope_id == 0 ||
srv6->sin6_scope_id == in6p->sin6_scope_id) &&
#endif
(IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
return (1);
}
break;
default:
break;
}
return (0);
}
/*%
* look for (name,type,class) in the query section of packet (buf,eom)
*
* requires:
*\li buf + HFIXEDSZ <= eom
*
* returns:
*\li -1 : format error
*\li 0 : not found
*\li >0 : found
*
* author:
*\li 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(((const 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);
}
/*%
* is there a 1:1 mapping of (name,type,class)
* in (buf1,eom1) and (buf2,eom2)?
*
* returns:
*\li -1 : format error
*\li 0 : not a 1:1 mapping
*\li >0 : is a 1:1 mapping
*
* author:
*\li 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(((const HEADER*)buf1)->qdcount);
if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
return (-1);
/*
* Only header section present in replies to
* dynamic update packets.
*/
if ((((const HEADER *)buf1)->opcode == ns_o_update) &&
(((const HEADER *)buf2)->opcode == ns_o_update))
return (1);
if (qdcount != ntohs(((const 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)
{
int gotsomewhere, terrno, tries, v_circuit, resplen, ns, n;
char abuf[NI_MAXHOST];
#ifdef USE_POLL
highestFD = sysconf(_SC_OPEN_MAX) - 1;
#endif
/* No name servers or res_init() failure */
if (statp->nscount == 0 || EXT(statp).ext == NULL) {
errno = ESRCH;
return (-1);
}
if (anssiz < HFIXEDSZ) {
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;
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).nscount != 0) {
int needclose = 0;
struct sockaddr_storage peer;
ISC_SOCKLEN_T peerlen;
if (EXT(statp).nscount != statp->nscount)
needclose++;
else
for (ns = 0; ns < statp->nscount; ns++) {
if (statp->nsaddr_list[ns].sin_family &&
!sock_eq((struct sockaddr *)&statp->nsaddr_list[ns],
(struct sockaddr *)&EXT(statp).ext->nsaddrs[ns])) {
needclose++;
break;
}
if (EXT(statp).nssocks[ns] == -1)
continue;
peerlen = sizeof(peer);
if (getpeername(EXT(statp).nssocks[ns],
(struct sockaddr *)&peer, &peerlen) < 0) {
needclose++;
break;
}
if (!sock_eq((struct sockaddr *)&peer,
get_nsaddr(statp, ns))) {
needclose++;
break;
}
}
if (needclose) {
res_nclose(statp);
EXT(statp).nscount = 0;
}
}
/*
* Maybe initialize our private copy of the ns_addr_list.
*/
if (EXT(statp).nscount == 0) {
for (ns = 0; ns < statp->nscount; ns++) {
EXT(statp).nstimes[ns] = RES_MAXTIME;
EXT(statp).nssocks[ns] = -1;
if (!statp->nsaddr_list[ns].sin_family)
continue;
EXT(statp).ext->nsaddrs[ns].sin =
statp->nsaddr_list[ns];
}
EXT(statp).nscount = statp->nscount;
}
/*
* Some resolvers want to even out the load on their nameservers.
* Note that RES_BLAST overrides RES_ROTATE.
*/
if ((statp->options & RES_ROTATE) != 0U &&
(statp->options & RES_BLAST) == 0U) {
union res_sockaddr_union inu;
struct sockaddr_in ina;
int lastns = statp->nscount - 1;
int fd;
u_int16_t nstime;
if (EXT(statp).ext != NULL)
inu = EXT(statp).ext->nsaddrs[0];
ina = statp->nsaddr_list[0];
fd = EXT(statp).nssocks[0];
nstime = EXT(statp).nstimes[0];
for (ns = 0; ns < lastns; ns++) {
if (EXT(statp).ext != NULL)
EXT(statp).ext->nsaddrs[ns] =
EXT(statp).ext->nsaddrs[ns + 1];
statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
EXT(statp).nssocks[ns] = EXT(statp).nssocks[ns + 1];
EXT(statp).nstimes[ns] = EXT(statp).nstimes[ns + 1];
}
if (EXT(statp).ext != NULL)
EXT(statp).ext->nsaddrs[lastns] = inu;
statp->nsaddr_list[lastns] = ina;
EXT(statp).nssocks[lastns] = fd;
EXT(statp).nstimes[lastns] = nstime;
}
/*
* Send request, RETRY times, or until successful.
*/
for (tries = 0; tries < statp->retry; tries++) {
for (ns = 0; ns < statp->nscount; ns++) {
struct sockaddr *nsap;
int nsaplen;
nsap = get_nsaddr(statp, ns);
nsaplen = get_salen(nsap);
statp->_flags &= ~RES_F_LASTMASK;
statp->_flags |= (ns << RES_F_LASTSHIFT);
same_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:
goto fail;
}
} while (!done);
}
Dprint(((statp->options & RES_DEBUG) &&
getnameinfo(nsap, nsaplen, abuf, sizeof(abuf),
NULL, 0, niflags) == 0),
(stdout, ";; Querying server (# %d) address = %s\n",
ns + 1, abuf));
if (v_circuit) {
/* Use VC; at most one attempt per server. */
tries = statp->retry;
n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
ns);
if (n < 0)
goto fail;
if (n == 0)
goto next_ns;
resplen = n;
} else {
/* Use datagrams. */
n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
ns, tries, &v_circuit, &gotsomewhere);
if (n < 0)
goto fail;
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) == 0U) ||
(statp->options & RES_STAYOPEN) == 0U) {
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:
goto fail;
}
} while (!done);
}
return (resplen);
next_ns: ;
} /*foreach ns*/
} /*foreach retry*/
res_nclose(statp);
if (!v_circuit) {
if (!gotsomewhere)
errno = ECONNREFUSED; /*%< no nameservers found */
else
errno = ETIMEDOUT; /*%< no answer obtained */
} else
errno = terrno;
return (-1);
fail:
res_nclose(statp);
return (-1);
}
/* Private */
static int
get_salen(sa)
const struct sockaddr *sa;
{
#ifdef HAVE_SA_LEN
/* There are people do not set sa_len. Be forgiving to them. */
if (sa->sa_len)
return (sa->sa_len);
#endif
if (sa->sa_family == AF_INET)
return (sizeof(struct sockaddr_in));
else if (sa->sa_family == AF_INET6)
return (sizeof(struct sockaddr_in6));
else
return (0); /*%< unknown, die on connect */
}
/*%
* pick appropriate nsaddr_list for use. see res_init() for initialization.
*/
static struct sockaddr *
get_nsaddr(statp, n)
res_state statp;
size_t n;
{
if (!statp->nsaddr_list[n].sin_family && EXT(statp).ext) {
/*
* - EXT(statp).ext->nsaddrs[n] holds an address that is larger
* than struct sockaddr, and
* - user code did not update statp->nsaddr_list[n].
*/
return (struct sockaddr *)(void *)&EXT(statp).ext->nsaddrs[n];
} else {
/*
* - user code updated statp->nsaddr_list[n], or
* - statp->nsaddr_list[n] has the same content as
* EXT(statp).ext->nsaddrs[n].
*/
return (struct sockaddr *)(void *)&statp->nsaddr_list[n];
}
}
static int
send_vc(res_state statp,
const u_char *buf, int buflen, u_char *ans, int anssiz,
int *terrno, int ns)
{
const HEADER *hp = (const HEADER *) buf;
HEADER *anhp = (HEADER *) ans;
struct sockaddr *nsap;
int nsaplen;
int truncating, connreset, resplen, n;
struct iovec iov[2];
u_short len;
u_char *cp;
void *tmp;
#ifdef SO_NOSIGPIPE
int on = 1;
#endif
nsap = get_nsaddr(statp, ns);
nsaplen = get_salen(nsap);
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_storage peer;
ISC_SOCKLEN_T size = sizeof peer;
if (getpeername(statp->_vcsock,
(struct sockaddr *)&peer, &size) < 0 ||
!sock_eq((struct sockaddr *)&peer, nsap)) {
res_nclose(statp);
statp->_flags &= ~RES_F_VC;
}
}
if (statp->_vcsock < 0 || (statp->_flags & RES_F_VC) == 0) {
if (statp->_vcsock >= 0)
res_nclose(statp);
statp->_vcsock = socket(nsap->sa_family, SOCK_STREAM, 0);
if (statp->_vcsock > highestFD) {
res_nclose(statp);
errno = ENOTSOCK;
}
if (statp->_vcsock < 0) {
switch (errno) {
case EPROTONOSUPPORT:
#ifdef EPFNOSUPPORT
case EPFNOSUPPORT:
#endif
case EAFNOSUPPORT:
Perror(statp, stderr, "socket(vc)", errno);
return (0);
default:
*terrno = errno;
Perror(statp, stderr, "socket(vc)", errno);
return (-1);
}
}
#ifdef SO_NOSIGPIPE
/*
* Disable generation of SIGPIPE when writing to a closed
* socket. Write should return -1 and set errno to EPIPE
* instead.
*
* Push on even if setsockopt(SO_NOSIGPIPE) fails.
*/
(void)setsockopt(statp->_vcsock, SOL_SOCKET, SO_NOSIGPIPE, &on,
sizeof(on));
#endif
errno = 0;
if (connect(statp->_vcsock, nsap, nsaplen) < 0) {
*terrno = errno;
Aerror(statp, stderr, "connect/vc", errno, nsap,
nsaplen);
res_nclose(statp);
return (0);
}
statp->_flags |= RES_F_VC;
}
/*
* Send length & message
*/
ns_put16((u_short)buflen, (u_char*)&len);
iov[0] = evConsIovec(&len, INT16SZ);
DE_CONST(buf, tmp);
iov[1] = evConsIovec(tmp, buflen);
if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
*terrno = errno;
Perror(statp, stderr, "write failed", errno);
res_nclose(statp);
return (0);
}
/*
* Receive length & response
*/
read_len:
cp = ans;
len = INT16SZ;
while ((n = 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_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);
return (0);
}
resplen = ns_get16(ans);
if (resplen > anssiz) {
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_nclose(statp);
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_nclose(statp);
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 *ans,
int anssiz, int *terrno, int ns, int tries, int *v_circuit,
int *gotsomewhere)
{
const HEADER *hp = (const HEADER *) buf;
HEADER *anhp = (HEADER *) ans;
const struct sockaddr *nsap;
int nsaplen;
struct timespec now, timeout, finish;
struct sockaddr_storage from;
ISC_SOCKLEN_T fromlen;
int resplen, seconds, n, s;
#ifdef USE_POLL
int polltimeout;
struct pollfd pollfd;
#else
fd_set dsmask;
#endif
nsap = get_nsaddr(statp, ns);
nsaplen = get_salen(nsap);
if (EXT(statp).nssocks[ns] == -1) {
EXT(statp).nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM, 0);
if (EXT(statp).nssocks[ns] > highestFD) {
res_nclose(statp);
errno = ENOTSOCK;
}
if (EXT(statp).nssocks[ns] < 0) {
switch (errno) {
case EPROTONOSUPPORT:
#ifdef EPFNOSUPPORT
case EPFNOSUPPORT:
#endif
case EAFNOSUPPORT:
Perror(statp, stderr, "socket(dg)", errno);
return (0);
default:
*terrno = errno;
Perror(statp, stderr, "socket(dg)", errno);
return (-1);
}
}
#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 (connect(EXT(statp).nssocks[ns], nsap, nsaplen) < 0) {
Aerror(statp, stderr, "connect(dg)", errno, nsap,
nsaplen);
res_nclose(statp);
return (0);
}
#endif /* !CANNOT_CONNECT_DGRAM */
Dprint(statp->options & RES_DEBUG,
(stdout, ";; new DG socket\n"))
}
s = EXT(statp).nssocks[ns];
#ifndef CANNOT_CONNECT_DGRAM
if (send(s, (const char*)buf, buflen, 0) != buflen) {
Perror(statp, stderr, "send", errno);
res_nclose(statp);
return (0);
}
#else /* !CANNOT_CONNECT_DGRAM */
if (sendto(s, (const char*)buf, buflen, 0, nsap, nsaplen) != buflen)
{
Aerror(statp, stderr, "sendto", errno, nsap, nsaplen);
res_nclose(statp);
return (0);
}
#endif /* !CANNOT_CONNECT_DGRAM */
/*
* Wait for reply.
*/
seconds = (statp->retrans << tries);
if (ns > 0)
seconds /= statp->nscount;
if (seconds <= 0)
seconds = 1;
now = evNowTime();
timeout = evConsTime(seconds, 0);
finish = evAddTime(now, timeout);
goto nonow;
wait:
now = evNowTime();
nonow:
#ifndef USE_POLL
FD_ZERO(&dsmask);
FD_SET(s, &dsmask);
if (evCmpTime(finish, now) > 0)
timeout = evSubTime(finish, now);
else
timeout = evConsTime(0, 0);
n = pselect(s + 1, &dsmask, NULL, NULL, &timeout, NULL);
#else
timeout = evSubTime(finish, now);
if (timeout.tv_sec < 0)
timeout = evConsTime(0, 0);
polltimeout = 1000*timeout.tv_sec +
timeout.tv_nsec/1000000;
pollfd.fd = s;
pollfd.events = POLLRDNORM;
n = poll(&pollfd, 1, polltimeout);
#endif /* USE_POLL */
if (n == 0) {
Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
*gotsomewhere = 1;
return (0);
}
if (n < 0) {
if (errno == EINTR)
goto wait;
#ifndef USE_POLL
Perror(statp, stderr, "select", errno);
#else
Perror(statp, stderr, "poll", errno);
#endif /* USE_POLL */
res_nclose(statp);
return (0);
}
errno = 0;
fromlen = sizeof(from);
resplen = recvfrom(s, (char*)ans, anssiz,0,
(struct sockaddr *)&from, &fromlen);
if (resplen <= 0) {
Perror(statp, stderr, "recvfrom", errno);
res_nclose(statp);
return (0);
}
*gotsomewhere = 1;
if (resplen < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(statp->options & RES_DEBUG,
(stdout, ";; undersized: %d\n",
resplen));
*terrno = EMSGSIZE;
res_nclose(statp);
return (0);
}
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, (struct sockaddr *)&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;
res_nclose(statp);
return (0);
}
#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);
res_nclose(statp);
/* don't retry if called from dig */
if (!statp->pfcode)
return (0);
}
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_nclose(statp);
return (1);
}
/*
* All is well, or the error is fatal. Signal that the
* next nameserver ought not be tried.
*/
return (resplen);
}
static void
Aerror(const res_state statp, FILE *file, const char *string, int error,
const struct sockaddr *address, int alen)
{
int save = errno;
char hbuf[NI_MAXHOST];
char sbuf[NI_MAXSERV];
alen = alen;
if ((statp->options & RES_DEBUG) != 0U) {
if (getnameinfo(address, alen, hbuf, sizeof(hbuf),
sbuf, sizeof(sbuf), niflags)) {
strncpy(hbuf, "?", sizeof(hbuf) - 1);
hbuf[sizeof(hbuf) - 1] = '\0';
strncpy(sbuf, "?", sizeof(sbuf) - 1);
sbuf[sizeof(sbuf) - 1] = '\0';
}
fprintf(file, "res_send: %s ([%s].%s): %s\n",
string, hbuf, sbuf, strerror(error));
}
errno = save;
}
static void
Perror(const res_state statp, FILE *file, const char *string, int error) {
int save = errno;
if ((statp->options & RES_DEBUG) != 0U)
fprintf(file, "res_send: %s: %s\n",
string, strerror(error));
errno = save;
}
static int
sock_eq(struct sockaddr *a, struct sockaddr *b) {
struct sockaddr_in *a4, *b4;
struct sockaddr_in6 *a6, *b6;
if (a->sa_family != b->sa_family)
return 0;
switch (a->sa_family) {
case AF_INET:
a4 = (struct sockaddr_in *)a;
b4 = (struct sockaddr_in *)b;
return a4->sin_port == b4->sin_port &&
a4->sin_addr.s_addr == b4->sin_addr.s_addr;
case AF_INET6:
a6 = (struct sockaddr_in6 *)a;
b6 = (struct sockaddr_in6 *)b;
return a6->sin6_port == b6->sin6_port &&
#ifdef HAVE_SIN6_SCOPE_ID
a6->sin6_scope_id == b6->sin6_scope_id &&
#endif
IN6_ARE_ADDR_EQUAL(&a6->sin6_addr, &b6->sin6_addr);
default:
return 0;
}
}
#if defined(NEED_PSELECT) && !defined(USE_POLL)
/* 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
