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freebsd-skq/lib/libc/net/res_send.c
Hajimu UMEMOTO 676e98714d - Make it possible to turn on RES_INSECURE[12] with /etc/resolv.conf. 
- Don't connect datagram socket if RES_INSECURE1.
- Needed to implement IPv6 anycast UDP DNS queries as documented in
  <draft-ietf-ipngwg-dns-discovery-03.txt>.

Obtained from:	KAME
2001-12-26 21:21:10 +00:00

940 lines
24 KiB
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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.
* 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.
*/
/*
* Portions Copyright (c) 1996 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 char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
static char rcsid[] = "$FreeBSD$";
#endif /* LIBC_SCCS and not lint */
/*
* Send query to name server and wait for reply.
*/
#include "namespace.h"
#include <sys/types.h>
#include <sys/event.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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"
#include "res_config.h"
static int s = -1; /* socket used for communications */
static int connected = 0; /* is the socket connected */
static int vc = 0; /* is the socket a virtual circuit? */
static int af = 0; /* address family of socket */
static res_send_qhook Qhook = NULL;
static res_send_rhook Rhook = NULL;
#define CAN_RECONNECT 1
#ifndef DEBUG
# define Dprint(cond, args) /*empty*/
# define DprintQ(cond, args, query, size) /*empty*/
# define Aerror(file, string, error, address) /*empty*/
# define Perror(file, string, error) /*empty*/
#else
# define Dprint(cond, args) if (cond) {fprintf args;} else {}
# define DprintQ(cond, args, query, size) if (cond) {\
fprintf args;\
__fp_nquery(query, size, stdout);\
} else {}
static char abuf[NI_MAXHOST];
static char pbuf[NI_MAXSERV];
static void Aerror __P((FILE *, char *, int, struct sockaddr *));
static void Perror __P((FILE *, char *, int));
static void
Aerror(file, string, error, address)
FILE *file;
char *string;
int error;
struct sockaddr *address;
{
int save = errno;
if (_res.options & RES_DEBUG) {
if (getnameinfo(address, address->sa_len, abuf, sizeof(abuf),
pbuf, sizeof(pbuf),
NI_NUMERICHOST|NI_NUMERICSERV|NI_WITHSCOPEID) != 0) {
strncpy(abuf, "?", sizeof(abuf));
strncpy(pbuf, "?", sizeof(pbuf));
}
fprintf(file, "res_send: %s ([%s].%s): %s\n",
string, abuf, pbuf, strerror(error));
}
errno = save;
}
static void
Perror(file, string, error)
FILE *file;
char *string;
int error;
{
int save = errno;
if (_res.options & RES_DEBUG) {
fprintf(file, "res_send: %s: %s\n",
string, strerror(error));
}
errno = save;
}
#endif
void
res_send_setqhook(hook)
res_send_qhook hook;
{
Qhook = hook;
}
void
res_send_setrhook(hook)
res_send_rhook hook;
{
Rhook = hook;
}
static struct sockaddr * get_nsaddr __P((size_t));
/*
* pick appropriate nsaddr_list for use. see res_init() for initialization.
*/
static struct sockaddr *
get_nsaddr(n)
size_t n;
{
if (!_res.nsaddr_list[n].sin_family) {
/*
* - _res_ext.nsaddr_list[n] holds an address that is larger
* than struct sockaddr, and
* - user code did not update _res.nsaddr_list[n].
*/
return (struct sockaddr *)&_res_ext.nsaddr_list[n];
} else {
/*
* - user code updated _res.nsaddr_list[n], or
* - _res.nsaddr_list[n] has the same content as
* _res_ext.nsaddr_list[n].
*/
return (struct sockaddr *)&_res.nsaddr_list[n];
}
}
/* int
* res_isourserver(ina)
* looks up "ina" in _res.ns_addr_list[]
* returns:
* 0 : not found
* >0 : found
* author:
* paul vixie, 29may94
*/
int
res_isourserver(inp)
const struct sockaddr_in *inp;
{
const struct sockaddr_in6 *in6p = (const struct sockaddr_in6 *)inp;
const struct sockaddr_in6 *srv6;
const struct sockaddr_in *srv;
int ns, ret;
ret = 0;
switch (inp->sin_family) {
case AF_INET6:
for (ns = 0; ns < _res.nscount; ns++) {
srv6 = (struct sockaddr_in6 *)get_nsaddr(ns);
if (srv6->sin6_family == in6p->sin6_family &&
srv6->sin6_port == in6p->sin6_port &&
srv6->sin6_scope_id == in6p->sin6_scope_id &&
(IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr,
&in6p->sin6_addr))) {
ret++;
break;
}
}
break;
case AF_INET:
for (ns = 0; ns < _res.nscount; ns++) {
srv = (struct sockaddr_in *)get_nsaddr(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)) {
ret++;
break;
}
}
break;
}
return (ret);
}
/* 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(name, type, class, buf, eom)
const char *name;
int type, class;
const u_char *buf, *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 &&
strcasecmp(tname, name) == 0)
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(buf1, eom1, buf2, eom2)
const u_char *buf1, *eom1;
const u_char *buf2, *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_send(buf, buflen, ans, anssiz)
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;
int kq;
u_int badns; /* XXX NSMAX can't exceed #/bits in this variable */
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
/* errno should have been set by res_init() in this case. */
return (-1);
}
if (anssiz < HFIXEDSZ) {
errno = EINVAL;
return (-1);
}
DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
(stdout, ";; res_send()\n"), buf, buflen);
v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
gotsomewhere = 0;
connreset = 0;
terrno = ETIMEDOUT;
badns = 0;
if ((kq = kqueue()) < 0) {
Perror(stderr, "kqueue", errno);
return (-1);
}
/*
* Send request, RETRY times, or until successful
*/
for (try = 0; try < _res.retry; try++) {
for (ns = 0; ns < _res.nscount; ns++) {
struct sockaddr *nsap = get_nsaddr(ns);
socklen_t salen;
if (nsap->sa_len)
salen = nsap->sa_len;
else if (nsap->sa_family == AF_INET6)
salen = sizeof(struct sockaddr_in6);
else if (nsap->sa_family == AF_INET)
salen = sizeof(struct sockaddr_in);
else
salen = 0; /*unknown, die on connect*/
same_ns:
if (badns & (1 << ns)) {
res_close();
goto next_ns;
}
if (Qhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*Qhook)((struct sockaddr_in **)&nsap,
&buf, &buflen,
ans, anssiz, &resplen);
switch (act) {
case res_goahead:
done = 1;
break;
case res_nextns:
res_close();
goto next_ns;
case res_done:
_close(kq);
return (resplen);
case res_modified:
/* give the hook another try */
if (++loops < 42) /*doug adams*/
break;
/*FALLTHROUGH*/
case res_error:
/*FALLTHROUGH*/
default:
_close(kq);
return (-1);
}
} while (!done);
}
Dprint((_res.options & RES_DEBUG) &&
getnameinfo(nsap, salen, abuf, sizeof(abuf),
NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) == 0,
(stdout, ";; Querying server (# %d) address = %s\n",
ns + 1, abuf));
if (v_circuit) {
int truncated;
struct iovec iov[2];
u_short len;
u_char *cp;
/*
* Use virtual circuit;
* at most one attempt per server.
*/
try = _res.retry;
truncated = 0;
if (s < 0 || !vc || hp->opcode == ns_o_update ||
af != nsap->sa_family) {
if (s >= 0)
res_close();
af = nsap->sa_family;
s = _socket(af, SOCK_STREAM, 0);
if (s < 0) {
terrno = errno;
Perror(stderr, "socket(vc)", errno);
badns |= (1 << ns);
res_close();
goto next_ns;
}
errno = 0;
if (_connect(s, nsap, salen) < 0) {
terrno = errno;
Aerror(stderr, "connect/vc",
errno, nsap);
badns |= (1 << ns);
res_close();
goto next_ns;
}
vc = 1;
}
/*
* 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(s, iov, 2) != (INT16SZ + buflen)) {
terrno = errno;
Perror(stderr, "write failed", errno);
badns |= (1 << ns);
res_close();
goto next_ns;
}
/*
* Receive length & response
*/
read_len:
cp = ans;
len = INT16SZ;
while ((n = _read(s, (char *)cp, (int)len)) > 0) {
cp += n;
if ((len -= n) <= 0)
break;
}
if (n <= 0) {
terrno = errno;
Perror(stderr, "read failed", errno);
res_close();
/*
* 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_close();
goto same_ns;
}
res_close();
goto next_ns;
}
resplen = ns_get16(ans);
if (resplen > anssiz) {
Dprint(_res.options & RES_DEBUG,
(stdout, ";; response truncated\n")
);
truncated = 1;
len = anssiz;
} else
len = resplen;
if (len < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(_res.options & RES_DEBUG,
(stdout, ";; undersized: %d\n", len));
terrno = EMSGSIZE;
badns |= (1 << ns);
res_close();
goto next_ns;
}
cp = ans;
while (len != 0 &&
(n = _read(s, (char *)cp, (int)len)) > 0) {
cp += n;
len -= n;
}
if (n <= 0) {
terrno = errno;
Perror(stderr, "read(vc)", errno);
res_close();
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 = (len > sizeof(junk)
? sizeof(junk)
: len);
if ((n = _read(s, junk, 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((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; old answer (unexpected):\n"),
ans, (resplen>anssiz)?anssiz:resplen);
goto read_len;
}
} else {
/*
* Use datagrams.
*/
struct kevent kv;
struct timespec ts;
struct timeval timeout, ctv;
struct sockaddr_storage from;
int fromlen;
if (s < 0 || vc || af != nsap->sa_family) {
if (vc)
res_close();
af = nsap->sa_family;
s = _socket(af, SOCK_DGRAM, 0);
if (s < 0) {
#ifndef CAN_RECONNECT
bad_dg_sock:
#endif
terrno = errno;
Perror(stderr, "socket(dg)", errno);
badns |= (1 << ns);
res_close();
goto next_ns;
}
connected = 0;
}
#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.
*
* When the option "insecure1" is specified, we'd
* rather expect to see responses from an "unknown"
* address. In order to let the kernel accept such
* responses, do not connect the socket here.
* XXX: or do we need an explicit option to disable
* connecting?
*/
if (!(_res.options & RES_INSECURE1) &&
(_res.nscount == 1 || (try == 0 && ns == 0))) {
/*
* Connect only if we are sure we won't
* receive a response from another server.
*/
if (!connected) {
if (_connect(s, nsap, salen) < 0) {
Aerror(stderr,
"connect(dg)",
errno, nsap);
badns |= (1 << ns);
res_close();
goto next_ns;
}
connected = 1;
}
if (send(s, (char*)buf, buflen, 0) != buflen) {
Perror(stderr, "send", errno);
badns |= (1 << ns);
res_close();
goto next_ns;
}
} else {
/*
* Disconnect if we want to listen
* for responses from more than one server.
*/
if (connected) {
#ifdef CAN_RECONNECT
/* XXX: any errornous address */
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(s,
(struct sockaddr *)
&no_addr,
sizeof no_addr);
#else
int s1 = _socket(af, SOCK_DGRAM,0);
if (s1 < 0)
goto bad_dg_sock;
(void)_dup2(s1, s);
(void)_close(s1);
Dprint(_res.options & RES_DEBUG,
(stdout, ";; new DG socket\n"))
#endif /* CAN_RECONNECT */
connected = 0;
errno = 0;
}
#endif /* !CANNOT_CONNECT_DGRAM */
if (_sendto(s, (char*)buf, buflen, 0,
nsap, salen) != buflen) {
Aerror(stderr, "sendto", errno, nsap);
badns |= (1 << ns);
res_close();
goto next_ns;
}
#ifndef CANNOT_CONNECT_DGRAM
}
#endif /* !CANNOT_CONNECT_DGRAM */
/*
* Wait for reply
*/
timeout.tv_sec = (_res.retrans << try);
if (try > 0)
timeout.tv_sec /= _res.nscount;
if ((long) timeout.tv_sec <= 0)
timeout.tv_sec = 1;
timeout.tv_usec = 0;
TIMEVAL_TO_TIMESPEC(&timeout, &ts);
(void) gettimeofday(&ctv, NULL);
timeradd(&timeout, &ctv, &timeout);
wait:
if (s < 0) {
Perror(stderr, "s out-of-bounds", EMFILE);
res_close();
goto next_ns;
}
EV_SET(&kv, s, EVFILT_READ, EV_ADD | EV_ONESHOT, 0,0,0);
n = _kevent(kq, &kv, 1, &kv, 1, &ts);
if (n < 0) {
if (errno == EINTR) {
(void) gettimeofday(&ctv, NULL);
if (timercmp(&ctv, &timeout, <)) {
timersub(&timeout, &ctv, &ctv);
TIMEVAL_TO_TIMESPEC(&ctv, &ts);
goto wait;
}
} else {
Perror(stderr, "kevent", errno);
res_close();
goto next_ns;
}
}
if (n == 0) {
/*
* timeout
*/
Dprint(_res.options & RES_DEBUG,
(stdout, ";; timeout\n"));
gotsomewhere = 1;
res_close();
goto next_ns;
}
errno = 0;
fromlen = sizeof(from);
resplen = _recvfrom(s, (char*)ans, anssiz, 0,
(struct sockaddr *)&from, &fromlen);
if (resplen <= 0) {
Perror(stderr, "recvfrom", errno);
res_close();
goto next_ns;
}
gotsomewhere = 1;
if (resplen < HFIXEDSZ) {
/*
* Undersized message.
*/
Dprint(_res.options & RES_DEBUG,
(stdout, ";; undersized: %d\n",
resplen));
terrno = EMSGSIZE;
badns |= (1 << ns);
res_close();
goto next_ns;
}
if (hp->id != anhp->id) {
/*
* response from old query, ignore it.
* XXX - potential security hazard could
* be detected here.
*/
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; old answer:\n"),
ans, (resplen>anssiz)?anssiz:resplen);
goto wait;
}
#ifdef CHECK_SRVR_ADDR
if (!(_res.options & RES_INSECURE1) &&
!res_isourserver((struct sockaddr_in *)&from)) {
/*
* response from wrong server? ignore it.
* XXX - potential security hazard could
* be detected here.
*/
DprintQ((_res.options & RES_DEBUG) ||
(_res.pfcode & RES_PRF_REPLY),
(stdout, ";; not our server:\n"),
ans, (resplen>anssiz)?anssiz:resplen);
goto wait;
}
#endif
if (!(_res.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((_res.options & RES_DEBUG) ||
(_res.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(_res.options & RES_DEBUG,
(stdout, "server rejected query:\n"),
ans, (resplen>anssiz)?anssiz:resplen);
badns |= (1 << ns);
res_close();
/* don't retry if called from dig */
if (!_res.pfcode)
goto next_ns;
}
if (!(_res.options & RES_IGNTC) && anhp->tc) {
/*
* get rest of answer;
* use TCP with same server.
*/
Dprint(_res.options & RES_DEBUG,
(stdout, ";; truncated answer\n"));
v_circuit = 1;
res_close();
goto same_ns;
}
} /*if vc/dg*/
Dprint((_res.options & RES_DEBUG) ||
((_res.pfcode & RES_PRF_REPLY) &&
(_res.pfcode & RES_PRF_HEAD1)),
(stdout, ";; got answer:\n"));
DprintQ((_res.options & RES_DEBUG) ||
(_res.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 && (!(_res.options & RES_USEVC) || ns != 0)) ||
!(_res.options & RES_STAYOPEN)) {
res_close();
}
if (Rhook) {
int done = 0, loops = 0;
do {
res_sendhookact act;
act = (*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_close();
goto next_ns;
case res_modified:
/* give the hook another try */
if (++loops < 42) /*doug adams*/
break;
/*FALLTHROUGH*/
case res_error:
/*FALLTHROUGH*/
default:
_close(kq);
return (-1);
}
} while (!done);
}
_close(kq);
return (resplen);
next_ns: ;
} /*foreach ns*/
} /*foreach retry*/
res_close();
_close(kq);
if (!v_circuit) {
if (!gotsomewhere)
errno = ECONNREFUSED; /* no nameservers found */
else
errno = ETIMEDOUT; /* no answer obtained */
} else
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_close()
{
if (s >= 0) {
(void)_close(s);
s = -1;
connected = 0;
vc = 0;
af = 0;
}
}
/*
* Weak aliases for applications that use certain private entry points,
* and fail to include <resolv.h>.
*/
#undef res_close
__weak_reference(__res_close, _res_close);
#undef res_send
__weak_reference(__res_send, res_send);
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