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bionic/libc/dns/resolv/res_send.c
Paul Jensen 41d9a50371 Add support for deleting per-network DNS resolver caches. 
This is required when the possible range of NetIds is large to
prevent netd consuming excessive amounts of memory.
This required replacing the per-cache locks in favor of a single
global lock to prevent accesses to deleted caches.

Change-Id: I99d058bafea5de743e56075dbed74031da4df63f
2014-05-14 04:16:18 -07:00

1352 lines
35 KiB
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/* $NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $ */
/*
* Copyright 2008 Android Open Source Project (source port randomization)
* 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.
*/
/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* 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 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.
*/
#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#ifdef notdef
static const char sccsid[] = "@(#)res_send.c 8.1 (Berkeley) 6/4/93";
static const char rcsid[] = "Id: res_send.c,v 1.5.2.2.4.5 2004/08/10 02:19:56 marka Exp";
#else
__RCSID("$NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
/* set to 1 to use our small/simple/limited DNS cache */
#define USE_RESOLV_CACHE 1
/*
* 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 <fcntl.h>
#include <netdb.h>
#ifdef ANDROID_CHANGES
#include "resolv_netid.h"
#include "resolv_private.h"
#else
#include <resolv.h>
#endif
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <isc/eventlib.h>
#if USE_RESOLV_CACHE
# include <resolv_cache.h>
#endif
#include "private/libc_logging.h"
#ifndef DE_CONST
#define DE_CONST(c,v) v = ((c) ? \
strchr((const void *)(c), *(const char *)(const void *)(c)) : NULL)
#endif
/* Options. Leave them on. */
#ifndef DEBUG
#define DEBUG
#endif
#include "res_debug.h"
#include "res_private.h"
#define EXT(res) ((res)->_u._ext)
#define DBG 0
static const int highestFD = FD_SETSIZE - 1;
/* 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 *);
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 *);
#ifdef NEED_PSELECT
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 int connect_with_timeout(int sock, const struct sockaddr *nsap,
socklen_t salen, int sec);
static int retrying_select(const int sock, fd_set *readset, fd_set *writeset,
const struct timespec *finish);
/* BIONIC-BEGIN: implement source port randomization */
typedef union {
struct sockaddr sa;
struct sockaddr_in sin;
struct sockaddr_in6 sin6;
} _sockaddr_union;
static int
random_bind( int s, int family )
{
_sockaddr_union u;
int j;
socklen_t slen;
/* clear all, this also sets the IP4/6 address to 'any' */
memset( &u, 0, sizeof u );
switch (family) {
case AF_INET:
u.sin.sin_family = family;
slen = sizeof u.sin;
break;
case AF_INET6:
u.sin6.sin6_family = family;
slen = sizeof u.sin6;
break;
default:
errno = EPROTO;
return -1;
}
/* first try to bind to a random source port a few times */
for (j = 0; j < 10; j++) {
/* find a random port between 1025 .. 65534 */
int port = 1025 + (res_randomid() % (65535-1025));
if (family == AF_INET)
u.sin.sin_port = htons(port);
else
u.sin6.sin6_port = htons(port);
if ( !bind( s, &u.sa, slen ) )
return 0;
}
/* nothing after 10 tries, our network table is probably busy */
/* let the system decide which port is best */
if (family == AF_INET)
u.sin.sin_port = 0;
else
u.sin6.sin6_port = 0;
return bind( s, &u.sa, slen );
}
/* BIONIC-END */
static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
/* Public. */
/* int
* res_isourserver(ina)
* looks up "ina" in _res.ns_addr_list[]
* returns:
* 0 : not found
* >0 : found
* author:
* paul vixie, 29may94
*/
__LIBC_HIDDEN__ 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 *)(const void *)sa;
for (ns = 0; ns < statp->nscount; ns++) {
srv = (struct sockaddr_in *)(void *)get_nsaddr(statp, (size_t)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 *)(const void *)sa;
for (ns = 0; ns < statp->nscount; ns++) {
srv6 = (struct sockaddr_in6 *)(void *)get_nsaddr(statp, (size_t)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);
}
/* 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(((const HEADER*)(const void *)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(((const HEADER*)(const void *)buf1)->qdcount);
if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
return (-1);
/*
* Only header section present in replies to
* dynamic update packets.
*/
if ((((const HEADER *)(const void *)buf1)->opcode == ns_o_update) &&
(((const HEADER *)(const void *)buf2)->opcode == ns_o_update))
return (1);
if (qdcount != ntohs(((const HEADER*)(const void *)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, try, v_circuit, resplen, ns, n;
char abuf[NI_MAXHOST];
#if USE_RESOLV_CACHE
ResolvCacheStatus cache_status = RESOLV_CACHE_UNSUPPORTED;
#endif
#if !USE_RESOLV_CACHE
if (statp->nscount == 0) {
errno = ESRCH;
return (-1);
}
#endif
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 USE_RESOLV_CACHE
int anslen = 0;
cache_status = _resolv_cache_lookup(
statp->netid, buf, buflen,
ans, anssiz, &anslen);
if (cache_status == RESOLV_CACHE_FOUND) {
return anslen;
} else if (cache_status != RESOLV_CACHE_UNSUPPORTED) {
// had a cache miss for a known network, so populate the thread private
// data so the normal resolve path can do its thing
_resolv_populate_res_for_net(statp);
}
if (statp->nscount == 0) {
errno = ESRCH;
return (-1);
}
#endif
/*
* 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;
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 *)(void *)&statp->nsaddr_list[ns],
(struct sockaddr *)(void *)&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 *)(void *)&peer, &peerlen) < 0) {
needclose++;
break;
}
if (!sock_eq((struct sockaddr *)(void *)&peer,
get_nsaddr(statp, (size_t)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 (try = 0; try < statp->retry; try++) {
for (ns = 0; ns < statp->nscount; ns++) {
struct sockaddr *nsap;
int nsaplen;
nsap = get_nsaddr(statp, (size_t)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, (socklen_t)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. */
try = statp->retry;
n = send_vc(statp, buf, buflen, ans, anssiz, &terrno,
ns);
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc",
"used send_vc %d\n", n);
}
if (n < 0)
goto fail;
if (n == 0)
goto next_ns;
resplen = n;
} else {
/* Use datagrams. */
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_dg\n");
}
n = send_dg(statp, buf, buflen, ans, anssiz, &terrno,
ns, &v_circuit, &gotsomewhere);
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", "used send_dg %d\n",n);
}
if (n < 0)
goto fail;
if (n == 0)
goto next_ns;
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", "time=%ld\n",
time(NULL));
}
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 USE_RESOLV_CACHE
if (cache_status == RESOLV_CACHE_NOTFOUND) {
_resolv_cache_add(statp->netid, buf, buflen,
ans, resplen);
}
#endif
/*
* 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;
#if USE_RESOLV_CACHE
_resolv_cache_query_failed(statp->netid, buf, buflen);
#endif
return (-1);
fail:
#if USE_RESOLV_CACHE
_resolv_cache_query_failed(statp->netid, buf, buflen);
#endif
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 get_timeout(const res_state statp, const int ns)
{
int timeout = (statp->retrans << ns);
if (ns > 0) {
timeout /= statp->nscount;
}
if (timeout <= 0) {
timeout = 1;
}
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using timeout of %d sec\n", timeout);
}
return timeout;
}
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 *)(const void *)buf;
HEADER *anhp = (HEADER *)(void *)ans;
struct sockaddr *nsap;
int nsaplen;
int truncating, connreset, resplen, n;
struct iovec iov[2];
u_short len;
u_char *cp;
void *tmp;
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", "using send_vc\n");
}
nsap = get_nsaddr(statp, (size_t)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;
socklen_t size = sizeof peer;
unsigned old_mark;
int mark_size = sizeof(old_mark);
if (getpeername(statp->_vcsock,
(struct sockaddr *)(void *)&peer, &size) < 0 ||
!sock_eq((struct sockaddr *)(void *)&peer, nsap) ||
getsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &old_mark, &mark_size) < 0 ||
old_mark != statp->_mark) {
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);
}
}
if (statp->_mark != MARK_UNSET) {
if (setsockopt(statp->_vcsock, SOL_SOCKET,
SO_MARK, &statp->_mark, sizeof(statp->_mark)) < 0) {
*terrno = errno;
Perror(statp, stderr, "setsockopt", errno);
return -1;
}
}
errno = 0;
if (random_bind(statp->_vcsock,nsap->sa_family) < 0) {
*terrno = errno;
Aerror(statp, stderr, "bind/vc", errno, nsap,
nsaplen);
res_nclose(statp);
return (0);
}
if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t)nsaplen,
get_timeout(statp, ns)) < 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*)(void *)&len);
iov[0] = evConsIovec(&len, INT16SZ);
DE_CONST(buf, tmp);
iov[1] = evConsIovec(tmp, (size_t)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, (size_t)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, (size_t)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);
}
/* return -1 on error (errno set), 0 on success */
static int
connect_with_timeout(int sock, const struct sockaddr *nsap, socklen_t salen, int sec)
{
int res, origflags;
fd_set rset, wset;
struct timespec now, timeout, finish;
origflags = fcntl(sock, F_GETFL, 0);
fcntl(sock, F_SETFL, origflags | O_NONBLOCK);
res = connect(sock, nsap, salen);
if (res < 0 && errno != EINPROGRESS) {
res = -1;
goto done;
}
if (res != 0) {
now = evNowTime();
timeout = evConsTime((long)sec, 0L);
finish = evAddTime(now, timeout);
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", " %d send_vc\n", sock);
}
res = retrying_select(sock, &rset, &wset, &finish);
if (res <= 0) {
res = -1;
}
}
done:
fcntl(sock, F_SETFL, origflags);
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc",
" %d connect_with_timeout returning %d\n", sock, res);
}
return res;
}
static int
retrying_select(const int sock, fd_set *readset, fd_set *writeset, const struct timespec *finish)
{
struct timespec now, timeout;
int n, error;
socklen_t len;
retry:
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc", " %d retying_select\n", sock);
}
now = evNowTime();
if (readset) {
FD_ZERO(readset);
FD_SET(sock, readset);
}
if (writeset) {
FD_ZERO(writeset);
FD_SET(sock, writeset);
}
if (evCmpTime(*finish, now) > 0)
timeout = evSubTime(*finish, now);
else
timeout = evConsTime(0L, 0L);
n = pselect(sock + 1, readset, writeset, NULL, &timeout, NULL);
if (n == 0) {
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, " libc",
" %d retrying_select timeout\n", sock);
}
errno = ETIMEDOUT;
return 0;
}
if (n < 0) {
if (errno == EINTR)
goto retry;
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc",
" %d retrying_select got error %d\n",sock, n);
}
return n;
}
if ((readset && FD_ISSET(sock, readset)) || (writeset && FD_ISSET(sock, writeset))) {
len = sizeof(error);
if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) {
errno = error;
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc",
" %d retrying_select dot error2 %d\n", sock, errno);
}
return -1;
}
}
if (DBG) {
__libc_format_log(ANDROID_LOG_DEBUG, "libc",
" %d retrying_select returning %d\n",sock, n);
}
return n;
}
static int
send_dg(res_state statp,
const u_char *buf, int buflen, u_char *ans, int anssiz,
int *terrno, int ns, int *v_circuit, int *gotsomewhere)
{
const HEADER *hp = (const HEADER *)(const void *)buf;
HEADER *anhp = (HEADER *)(void *)ans;
const struct sockaddr *nsap;
int nsaplen;
struct timespec now, timeout, finish;
fd_set dsmask;
struct sockaddr_storage from;
socklen_t fromlen;
int resplen, seconds, n, s;
nsap = get_nsaddr(statp, (size_t)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);
}
}
if (statp->_mark != MARK_UNSET) {
if (setsockopt(EXT(statp).nssocks[ns], SOL_SOCKET,
SO_MARK, &(statp->_mark), sizeof(statp->_mark)) < 0) {
res_nclose(statp);
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 (random_bind(EXT(statp).nssocks[ns], nsap->sa_family) < 0) {
Aerror(statp, stderr, "bind(dg)", errno, nsap,
nsaplen);
res_nclose(statp);
return (0);
}
if (connect(EXT(statp).nssocks[ns], nsap, (socklen_t)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, (size_t)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 = get_timeout(statp, ns);
now = evNowTime();
timeout = evConsTime((long)seconds, 0L);
finish = evAddTime(now, timeout);
retry:
n = retrying_select(s, &dsmask, NULL, &finish);
if (n == 0) {
Dprint(statp->options & RES_DEBUG, (stdout, ";; timeout\n"));
*gotsomewhere = 1;
return (0);
}
if (n < 0) {
Perror(statp, stderr, "select", errno);
res_nclose(statp);
return (0);
}
errno = 0;
fromlen = sizeof(from);
resplen = recvfrom(s, (char*)ans, (size_t)anssiz,0,
(struct sockaddr *)(void *)&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.
*/
#ifdef ANDROID_CHANGES
__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_OLD_RESPONSE);
#endif
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; old answer:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto retry;
}
if (!(statp->options & RES_INSECURE1) &&
!res_ourserver_p(statp, (struct sockaddr *)(void *)&from)) {
/*
* response from wrong server? ignore it.
* XXX - potential security hazard could
* be detected here.
*/
#ifdef ANDROID_CHANGES
__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_SERVER);
#endif
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; not our server:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto retry;
}
#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.
*/
#ifdef ANDROID_CHANGES
__libc_android_log_event_uid(BIONIC_EVENT_RESOLVER_WRONG_QUERY);
#endif
DprintQ((statp->options & RES_DEBUG) ||
(statp->pfcode & RES_PRF_REPLY),
(stdout, ";; wrong query name:\n"),
ans, (resplen > anssiz) ? anssiz : resplen);
goto retry;;
}
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, (socklen_t)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 *)(void *)a;
b4 = (struct sockaddr_in *)(void *)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 *)(void *)a;
b6 = (struct sockaddr_in6 *)(void *)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;
}
}
#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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