/* $NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $ */
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/*
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* Copyright (c) 1985, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies, and that
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* the name of Digital Equipment Corporation not be used in advertising or
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* publicity pertaining to distribution of the document or software without
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* specific, written prior permission.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
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* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
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* CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Send query to name server and wait for reply.
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*/
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#define LOG_TAG "res_send"
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/uio.h>
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <netinet/in.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <netdb.h>
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#include <poll.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#include <android-base/logging.h>
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#include <android/multinetwork.h> // ResNsendFlags
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#include <netdutils/Slice.h>
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#include "DnsTlsDispatcher.h"
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#include "DnsTlsTransport.h"
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#include "PrivateDnsConfiguration.h"
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#include "netd_resolv/resolv.h"
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#include "netd_resolv/stats.h"
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#include "private/android_filesystem_config.h"
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#include "res_state_ext.h"
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#include "resolv_cache.h"
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#include "resolv_private.h"
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// TODO: use the namespace something like android::netd_resolv for libnetd_resolv
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using namespace android::net;
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using android::netdutils::Slice;
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static DnsTlsDispatcher sDnsTlsDispatcher;
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static int get_salen(const struct sockaddr*);
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static struct sockaddr* get_nsaddr(res_state, size_t);
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static int send_vc(res_state, res_params* params, const u_char*, int, u_char*, int, int*, int,
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time_t*, int*, int*);
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static int send_dg(res_state, res_params* params, const u_char*, int, u_char*, int, int*, int, int*,
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int*, time_t*, int*, int*);
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static void Aerror(const res_state, const char*, int, const struct sockaddr*, int);
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static void Perror(const res_state, const char*, int);
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static int sock_eq(struct sockaddr*, struct sockaddr*);
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static int connect_with_timeout(int sock, const struct sockaddr* nsap, socklen_t salen,
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const struct timespec timeout);
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static int retrying_poll(const int sock, short events, const struct timespec* finish);
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static int res_tls_send(res_state, const Slice query, const Slice answer, int* rcode,
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bool* fallback);
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/* BIONIC-BEGIN: implement source port randomization */
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// BEGIN: Code copied from ISC eventlib
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// TODO: move away from this code
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#define BILLION 1000000000
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static struct timespec evConsTime(time_t sec, long nsec) {
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struct timespec x;
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x.tv_sec = sec;
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x.tv_nsec = nsec;
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return (x);
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}
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static struct timespec evAddTime(struct timespec addend1, struct timespec addend2) {
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struct timespec x;
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x.tv_sec = addend1.tv_sec + addend2.tv_sec;
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x.tv_nsec = addend1.tv_nsec + addend2.tv_nsec;
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if (x.tv_nsec >= BILLION) {
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x.tv_sec++;
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x.tv_nsec -= BILLION;
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}
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return (x);
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}
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static struct timespec evSubTime(struct timespec minuend, struct timespec subtrahend) {
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struct timespec x;
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x.tv_sec = minuend.tv_sec - subtrahend.tv_sec;
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if (minuend.tv_nsec >= subtrahend.tv_nsec)
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x.tv_nsec = minuend.tv_nsec - subtrahend.tv_nsec;
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else {
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x.tv_nsec = BILLION - subtrahend.tv_nsec + minuend.tv_nsec;
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x.tv_sec--;
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}
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return (x);
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}
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static int evCmpTime(struct timespec a, struct timespec b) {
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#define SGN(x) ((x) < 0 ? (-1) : (x) > 0 ? (1) : (0));
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time_t s = a.tv_sec - b.tv_sec;
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long n;
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if (s != 0) return SGN(s);
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n = a.tv_nsec - b.tv_nsec;
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return SGN(n);
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}
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static struct timespec evNowTime(void) {
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struct timespec tsnow;
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clock_gettime(CLOCK_REALTIME, &tsnow);
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return tsnow;
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}
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static struct iovec evConsIovec(void* buf, size_t cnt) {
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struct iovec ret;
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memset(&ret, 0xf5, sizeof ret);
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ret.iov_base = buf;
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ret.iov_len = cnt;
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return ret;
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}
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// END: Code copied from ISC eventlib
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static int random_bind(int s, int family) {
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sockaddr_union u;
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int j;
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socklen_t slen;
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/* clear all, this also sets the IP4/6 address to 'any' */
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memset(&u, 0, sizeof u);
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switch (family) {
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case AF_INET:
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u.sin.sin_family = family;
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slen = sizeof u.sin;
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break;
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case AF_INET6:
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u.sin6.sin6_family = family;
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slen = sizeof u.sin6;
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break;
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default:
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errno = EPROTO;
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return -1;
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}
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/* first try to bind to a random source port a few times */
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for (j = 0; j < 10; j++) {
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/* find a random port between 1025 .. 65534 */
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int port = 1025 + (arc4random_uniform(65535 - 1025));
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if (family == AF_INET)
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u.sin.sin_port = htons(port);
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else
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u.sin6.sin6_port = htons(port);
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if (!bind(s, &u.sa, slen)) return 0;
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}
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// nothing after 10 attempts, our network table is probably busy
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// let the system decide which port is best
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if (family == AF_INET)
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u.sin.sin_port = 0;
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else
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u.sin6.sin6_port = 0;
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return bind(s, &u.sa, slen);
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}
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/* BIONIC-END */
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// Disables all nameservers other than selectedServer
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static void res_set_usable_server(int selectedServer, int nscount, bool usable_servers[]) {
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int usableIndex = 0;
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for (int ns = 0; ns < nscount; ns++) {
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if (usable_servers[ns]) ++usableIndex;
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if (usableIndex != selectedServer) usable_servers[ns] = false;
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}
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}
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/* int
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* res_isourserver(ina)
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* looks up "ina" in _res.ns_addr_list[]
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* returns:
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* 0 : not found
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* >0 : found
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* author:
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* paul vixie, 29may94
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*/
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static int res_ourserver_p(const res_state statp, const sockaddr* sa) {
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const sockaddr_in *inp, *srv;
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const sockaddr_in6 *in6p, *srv6;
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int ns;
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switch (sa->sa_family) {
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case AF_INET:
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inp = (const struct sockaddr_in*) (const void*) sa;
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for (ns = 0; ns < statp->nscount; ns++) {
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srv = (struct sockaddr_in*) (void*) get_nsaddr(statp, (size_t) ns);
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if (srv->sin_family == inp->sin_family && srv->sin_port == inp->sin_port &&
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(srv->sin_addr.s_addr == INADDR_ANY ||
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srv->sin_addr.s_addr == inp->sin_addr.s_addr))
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return 1;
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}
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break;
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case AF_INET6:
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if (statp->_u._ext.ext == NULL) break;
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in6p = (const struct sockaddr_in6*) (const void*) sa;
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for (ns = 0; ns < statp->nscount; ns++) {
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srv6 = (struct sockaddr_in6*) (void*) get_nsaddr(statp, (size_t) ns);
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if (srv6->sin6_family == in6p->sin6_family && srv6->sin6_port == in6p->sin6_port &&
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#ifdef HAVE_SIN6_SCOPE_ID
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(srv6->sin6_scope_id == 0 || srv6->sin6_scope_id == in6p->sin6_scope_id) &&
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#endif
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(IN6_IS_ADDR_UNSPECIFIED(&srv6->sin6_addr) ||
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IN6_ARE_ADDR_EQUAL(&srv6->sin6_addr, &in6p->sin6_addr)))
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return 1;
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}
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break;
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default:
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break;
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}
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return 0;
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}
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/* int
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* res_nameinquery(name, type, cl, buf, eom)
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* look for (name, type, cl) in the query section of packet (buf, eom)
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* requires:
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* buf + HFIXEDSZ <= eom
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* returns:
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* -1 : format error
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* 0 : not found
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* >0 : found
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* author:
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* paul vixie, 29may94
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*/
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int res_nameinquery(const char* name, int type, int cl, const u_char* buf, const u_char* eom) {
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const u_char* cp = buf + HFIXEDSZ;
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int qdcount = ntohs(((const HEADER*) (const void*) buf)->qdcount);
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while (qdcount-- > 0) {
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char tname[MAXDNAME + 1];
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int n = dn_expand(buf, eom, cp, tname, sizeof tname);
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if (n < 0) return (-1);
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cp += n;
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if (cp + 2 * INT16SZ > eom) return (-1);
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int ttype = ntohs(*reinterpret_cast<const uint16_t*>(cp));
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cp += INT16SZ;
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int tclass = ntohs(*reinterpret_cast<const uint16_t*>(cp));
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cp += INT16SZ;
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if (ttype == type && tclass == cl && ns_samename(tname, name) == 1) return (1);
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}
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return (0);
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}
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/* int
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* res_queriesmatch(buf1, eom1, buf2, eom2)
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* is there a 1:1 mapping of (name,type,class)
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* in (buf1,eom1) and (buf2,eom2)?
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* returns:
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* -1 : format error
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* 0 : not a 1:1 mapping
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* >0 : is a 1:1 mapping
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* author:
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* paul vixie, 29may94
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*/
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int res_queriesmatch(const u_char* buf1, const u_char* eom1, const u_char* buf2,
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const u_char* eom2) {
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const u_char* cp = buf1 + HFIXEDSZ;
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int qdcount = ntohs(((const HEADER*) (const void*) buf1)->qdcount);
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if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2) return (-1);
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/*
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* Only header section present in replies to
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* dynamic update packets.
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*/
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if ((((const HEADER*) (const void*) buf1)->opcode == ns_o_update) &&
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(((const HEADER*) (const void*) buf2)->opcode == ns_o_update))
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return (1);
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if (qdcount != ntohs(((const HEADER*) (const void*) buf2)->qdcount)) return (0);
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while (qdcount-- > 0) {
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char tname[MAXDNAME + 1];
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int n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
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if (n < 0) return (-1);
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cp += n;
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if (cp + 2 * INT16SZ > eom1) return (-1);
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int ttype = ntohs(*reinterpret_cast<const uint16_t*>(cp));
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cp += INT16SZ;
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int tclass = ntohs(*reinterpret_cast<const uint16_t*>(cp));
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cp += INT16SZ;
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if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0);
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}
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return (1);
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}
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int res_nsend(res_state statp, const u_char* buf, int buflen, u_char* ans, int anssiz, int* rcode,
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uint32_t flags) {
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int gotsomewhere, terrno, v_circuit, resplen, n;
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ResolvCacheStatus cache_status = RESOLV_CACHE_UNSUPPORTED;
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if (anssiz < HFIXEDSZ) {
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// TODO: Remove errno once callers stop using it
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errno = EINVAL;
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return -EINVAL;
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}
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LOG(DEBUG) << __func__;
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res_pquery(buf, buflen);
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v_circuit = (statp->options & RES_USEVC) || buflen > PACKETSZ;
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gotsomewhere = 0;
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terrno = ETIMEDOUT;
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int anslen = 0;
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cache_status = _resolv_cache_lookup(statp->netid, buf, buflen, ans, anssiz, &anslen, flags);
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if (cache_status == RESOLV_CACHE_FOUND) {
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HEADER* hp = (HEADER*)(void*)ans;
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*rcode = hp->rcode;
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return anslen;
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} else if (cache_status != RESOLV_CACHE_UNSUPPORTED) {
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// had a cache miss for a known network, so populate the thread private
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// data so the normal resolve path can do its thing
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_resolv_populate_res_for_net(statp);
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}
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if (statp->nscount == 0) {
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// We have no nameservers configured, so there's no point trying.
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// Tell the cache the query failed, or any retries and anyone else asking the same
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// question will block for PENDING_REQUEST_TIMEOUT seconds instead of failing fast.
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_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
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// TODO: Remove errno once callers stop using it
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errno = ESRCH;
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return -ESRCH;
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}
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/*
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* If the ns_addr_list in the resolver context has changed, then
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* invalidate our cached copy and the associated timing data.
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*/
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if (statp->_u._ext.nscount != 0) {
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int needclose = 0;
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struct sockaddr_storage peer;
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socklen_t peerlen;
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if (statp->_u._ext.nscount != statp->nscount) {
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needclose++;
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} else {
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for (int ns = 0; ns < statp->nscount; ns++) {
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if (statp->nsaddr_list[ns].sin_family &&
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!sock_eq((struct sockaddr*) (void*) &statp->nsaddr_list[ns],
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(struct sockaddr*) (void*) &statp->_u._ext.ext->nsaddrs[ns])) {
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needclose++;
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break;
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}
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if (statp->_u._ext.nssocks[ns] == -1) continue;
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peerlen = sizeof(peer);
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if (getpeername(statp->_u._ext.nssocks[ns], (struct sockaddr*) (void*) &peer,
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&peerlen) < 0) {
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needclose++;
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break;
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}
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if (!sock_eq((struct sockaddr*) (void*) &peer, get_nsaddr(statp, (size_t) ns))) {
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needclose++;
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break;
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}
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}
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}
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if (needclose) {
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res_nclose(statp);
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statp->_u._ext.nscount = 0;
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}
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}
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/*
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* Maybe initialize our private copy of the ns_addr_list.
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*/
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if (statp->_u._ext.nscount == 0) {
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for (int ns = 0; ns < statp->nscount; ns++) {
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statp->_u._ext.nstimes[ns] = RES_MAXTIME;
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statp->_u._ext.nssocks[ns] = -1;
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if (!statp->nsaddr_list[ns].sin_family) continue;
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statp->_u._ext.ext->nsaddrs[ns].sin = statp->nsaddr_list[ns];
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}
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statp->_u._ext.nscount = statp->nscount;
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}
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/*
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* Some resolvers want to even out the load on their nameservers.
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* Note that RES_BLAST overrides RES_ROTATE.
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*/
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if ((statp->options & RES_ROTATE) != 0U && (statp->options & RES_BLAST) == 0U) {
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sockaddr_union inu;
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struct sockaddr_in ina;
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int lastns = statp->nscount - 1;
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int fd;
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u_int16_t nstime;
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if (statp->_u._ext.ext != NULL) inu = statp->_u._ext.ext->nsaddrs[0];
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ina = statp->nsaddr_list[0];
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fd = statp->_u._ext.nssocks[0];
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nstime = statp->_u._ext.nstimes[0];
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for (int ns = 0; ns < lastns; ns++) {
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if (statp->_u._ext.ext != NULL)
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statp->_u._ext.ext->nsaddrs[ns] = statp->_u._ext.ext->nsaddrs[ns + 1];
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statp->nsaddr_list[ns] = statp->nsaddr_list[ns + 1];
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statp->_u._ext.nssocks[ns] = statp->_u._ext.nssocks[ns + 1];
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statp->_u._ext.nstimes[ns] = statp->_u._ext.nstimes[ns + 1];
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}
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if (statp->_u._ext.ext != NULL) statp->_u._ext.ext->nsaddrs[lastns] = inu;
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statp->nsaddr_list[lastns] = ina;
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statp->_u._ext.nssocks[lastns] = fd;
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statp->_u._ext.nstimes[lastns] = nstime;
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}
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|
res_stats stats[MAXNS];
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res_params params;
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int revision_id = resolv_cache_get_resolver_stats(statp->netid, ¶ms, stats);
|
if (revision_id < 0) {
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// TODO: Remove errno once callers stop using it
|
errno = ESRCH;
|
return -ESRCH;
|
}
|
bool usable_servers[MAXNS];
|
int usableServersCount = android_net_res_stats_get_usable_servers(
|
¶ms, stats, statp->nscount, usable_servers);
|
|
if ((flags & ANDROID_RESOLV_NO_RETRY) && usableServersCount > 1) {
|
auto hp = reinterpret_cast<const HEADER*>(buf);
|
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// Select a random server based on the query id
|
int selectedServer = (hp->id % usableServersCount) + 1;
|
res_set_usable_server(selectedServer, statp->nscount, usable_servers);
|
}
|
|
/*
|
* Send request, RETRY times, or until successful.
|
*/
|
int retryTimes = (flags & ANDROID_RESOLV_NO_RETRY) ? 1 : params.retry_count;
|
|
for (int attempt = 0; attempt < retryTimes; ++attempt) {
|
|
for (int ns = 0; ns < statp->nscount; ns++) {
|
if (!usable_servers[ns]) continue;
|
struct sockaddr* nsap;
|
int nsaplen;
|
time_t now = 0;
|
int delay = 0;
|
*rcode = RCODE_INTERNAL_ERROR;
|
nsap = get_nsaddr(statp, (size_t) ns);
|
nsaplen = get_salen(nsap);
|
|
same_ns:
|
// TODO: Since we expect there is only one DNS server being queried here while this
|
// function tries to query all of private DNS servers. Consider moving it to other
|
// reasonable place. In addition, maybe add stats for private DNS.
|
if (!statp->use_local_nameserver) {
|
bool fallback = false;
|
resplen = res_tls_send(statp, Slice(const_cast<u_char*>(buf), buflen),
|
Slice(ans, anssiz), rcode, &fallback);
|
if (resplen > 0) {
|
if (cache_status == RESOLV_CACHE_NOTFOUND) {
|
_resolv_cache_add(statp->netid, buf, buflen, ans, resplen);
|
}
|
return resplen;
|
}
|
if (!fallback) {
|
_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
|
res_nclose(statp);
|
return -terrno;
|
}
|
}
|
|
[[maybe_unused]] static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
|
[[maybe_unused]] char abuf[NI_MAXHOST];
|
|
if (getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), NULL, 0, niflags) == 0)
|
LOG(DEBUG) << __func__ << ": Querying server (# " << ns + 1
|
<< ") address = " << abuf;
|
|
if (v_circuit) {
|
/* Use VC; at most one attempt per server. */
|
bool shouldRecordStats = (attempt == 0);
|
attempt = retryTimes;
|
|
n = send_vc(statp, ¶ms, buf, buflen, ans, anssiz, &terrno, ns, &now, rcode,
|
&delay);
|
|
/*
|
* Only record stats the first time we try a query. This ensures that
|
* queries that deterministically fail (e.g., a name that always returns
|
* SERVFAIL or times out) do not unduly affect the stats.
|
*/
|
if (shouldRecordStats) {
|
res_sample sample;
|
_res_stats_set_sample(&sample, now, *rcode, delay);
|
_resolv_cache_add_resolver_stats_sample(statp->netid, revision_id, ns, &sample,
|
params.max_samples);
|
}
|
|
LOG(INFO) << __func__ << ": used send_vc " << n;
|
|
if (n < 0) {
|
_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
|
res_nclose(statp);
|
return -terrno;
|
};
|
if (n == 0) goto next_ns;
|
resplen = n;
|
} else {
|
/* Use datagrams. */
|
LOG(INFO) << __func__ << ": using send_dg";
|
|
n = send_dg(statp, ¶ms, buf, buflen, ans, anssiz, &terrno, ns, &v_circuit,
|
&gotsomewhere, &now, rcode, &delay);
|
|
/* Only record stats the first time we try a query. See above. */
|
if (attempt == 0) {
|
res_sample sample;
|
_res_stats_set_sample(&sample, now, *rcode, delay);
|
_resolv_cache_add_resolver_stats_sample(statp->netid, revision_id, ns, &sample,
|
params.max_samples);
|
}
|
|
LOG(INFO) << __func__ << ": used send_dg " << n;
|
|
if (n < 0) {
|
_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
|
res_nclose(statp);
|
return -terrno;
|
};
|
if (n == 0) goto next_ns;
|
if (v_circuit) goto same_ns;
|
resplen = n;
|
}
|
|
LOG(DEBUG) << __func__ << ": got answer:";
|
res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
|
|
if (cache_status == RESOLV_CACHE_NOTFOUND) {
|
_resolv_cache_add(statp->netid, buf, buflen, ans, 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);
|
}
|
return (resplen);
|
next_ns:;
|
} // for each ns
|
} // for each retry
|
res_nclose(statp);
|
if (!v_circuit) {
|
if (!gotsomewhere) {
|
// TODO: Remove errno once callers stop using it
|
errno = ECONNREFUSED; /* no nameservers found */
|
terrno = ECONNREFUSED;
|
} else {
|
// TODO: Remove errno once callers stop using it
|
errno = ETIMEDOUT; /* no answer obtained */
|
terrno = ETIMEDOUT;
|
}
|
} else {
|
errno = terrno;
|
}
|
_resolv_cache_query_failed(statp->netid, buf, buflen, flags);
|
return -terrno;
|
}
|
|
/* Private */
|
|
static int get_salen(const struct sockaddr* sa) {
|
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(res_state statp, size_t n) {
|
if (!statp->nsaddr_list[n].sin_family && statp->_u._ext.ext) {
|
/*
|
* - statp->_u._ext.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*) &statp->_u._ext.ext->nsaddrs[n];
|
} else {
|
/*
|
* - user code updated statp->nsaddr_list[n], or
|
* - statp->nsaddr_list[n] has the same content as
|
* statp->_u._ext.ext->nsaddrs[n].
|
*/
|
return (struct sockaddr*) (void*) &statp->nsaddr_list[n];
|
}
|
}
|
|
static struct timespec get_timeout(const res_state statp, const res_params* params, const int ns) {
|
int msec;
|
// Legacy algorithm which scales the timeout by nameserver number.
|
// For instance, with 4 nameservers: 5s, 2.5s, 5s, 10s
|
// This has no effect with 1 or 2 nameservers
|
msec = params->base_timeout_msec << ns;
|
if (ns > 0) {
|
msec /= statp->nscount;
|
}
|
// For safety, don't allow OEMs and experiments to configure a timeout shorter than 1s.
|
if (msec < 1000) {
|
msec = 1000; // Use at least 1000ms
|
}
|
LOG(INFO) << __func__ << ": using timeout of " << msec << " msec";
|
|
struct timespec result;
|
result.tv_sec = msec / 1000;
|
result.tv_nsec = (msec % 1000) * 1000000;
|
return result;
|
}
|
|
static int send_vc(res_state statp, res_params* params, const u_char* buf, int buflen, u_char* ans,
|
int anssiz, int* terrno, int ns, time_t* at, int* rcode, int* delay) {
|
*at = time(NULL);
|
*delay = 0;
|
const HEADER* hp = (const HEADER*) (const void*) buf;
|
HEADER* anhp = (HEADER*) (void*) ans;
|
struct sockaddr* nsap;
|
int nsaplen;
|
int truncating, connreset, n;
|
struct iovec iov[2];
|
u_char* cp;
|
|
LOG(INFO) << __func__ << ": using send_vc";
|
|
nsap = get_nsaddr(statp, (size_t) ns);
|
nsaplen = get_salen(nsap);
|
|
connreset = 0;
|
same_ns:
|
truncating = 0;
|
|
struct timespec now = evNowTime();
|
|
/* 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;
|
socklen_t 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 | SOCK_CLOEXEC, 0);
|
if (statp->_vcsock < 0) {
|
switch (errno) {
|
case EPROTONOSUPPORT:
|
case EPFNOSUPPORT:
|
case EAFNOSUPPORT:
|
Perror(statp, "socket(vc)", errno);
|
return 0;
|
default:
|
*terrno = errno;
|
Perror(statp, "socket(vc)", errno);
|
return -1;
|
}
|
}
|
fchown(statp->_vcsock, AID_DNS, -1);
|
if (statp->_mark != MARK_UNSET) {
|
if (setsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &statp->_mark,
|
sizeof(statp->_mark)) < 0) {
|
*terrno = errno;
|
Perror(statp, "setsockopt", errno);
|
return -1;
|
}
|
}
|
errno = 0;
|
if (random_bind(statp->_vcsock, nsap->sa_family) < 0) {
|
*terrno = errno;
|
Aerror(statp, "bind/vc", errno, nsap, nsaplen);
|
res_nclose(statp);
|
return (0);
|
}
|
if (connect_with_timeout(statp->_vcsock, nsap, (socklen_t) nsaplen,
|
get_timeout(statp, params, ns)) < 0) {
|
*terrno = errno;
|
Aerror(statp, "connect/vc", errno, nsap, nsaplen);
|
res_nclose(statp);
|
/*
|
* The way connect_with_timeout() is implemented prevents us from reliably
|
* determining whether this was really a timeout or e.g. ECONNREFUSED. Since
|
* currently both cases are handled in the same way, there is no need to
|
* change this (yet). If we ever need to reliably distinguish between these
|
* cases, both connect_with_timeout() and retrying_poll() need to be
|
* modified, though.
|
*/
|
*rcode = RCODE_TIMEOUT;
|
return (0);
|
}
|
statp->_flags |= RES_F_VC;
|
}
|
|
/*
|
* Send length & message
|
*/
|
uint16_t len = htons(static_cast<uint16_t>(buflen));
|
iov[0] = evConsIovec(&len, INT16SZ);
|
iov[1] = evConsIovec((void*) buf, (size_t) buflen);
|
if (writev(statp->_vcsock, iov, 2) != (INT16SZ + buflen)) {
|
*terrno = errno;
|
Perror(statp, "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, "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);
|
}
|
uint16_t resplen = ntohs(*reinterpret_cast<const uint16_t*>(ans));
|
if (resplen > anssiz) {
|
LOG(DEBUG) << __func__ << ": response truncated";
|
truncating = 1;
|
len = anssiz;
|
} else
|
len = resplen;
|
if (len < HFIXEDSZ) {
|
/*
|
* Undersized message.
|
*/
|
LOG(DEBUG) << __func__ << ": undersized: " << 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, "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;
|
}
|
LOG(WARNING) << __func__ << ": resplen " << resplen << " exceeds buf size " << anssiz;
|
// return size should never exceed container size
|
resplen = anssiz;
|
}
|
/*
|
* If the calling application 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) {
|
LOG(DEBUG) << __func__ << ": ld answer (unexpected):";
|
res_pquery(ans, resplen);
|
goto read_len;
|
}
|
|
/*
|
* All is well, or the error is fatal. Signal that the
|
* next nameserver ought not be tried.
|
*/
|
if (resplen > 0) {
|
struct timespec done = evNowTime();
|
*delay = _res_stats_calculate_rtt(&done, &now);
|
*rcode = anhp->rcode;
|
}
|
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,
|
const struct timespec timeout) {
|
int res, origflags;
|
|
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) {
|
struct timespec now = evNowTime();
|
struct timespec finish = evAddTime(now, timeout);
|
LOG(INFO) << __func__ << ": " << sock << " send_vc";
|
res = retrying_poll(sock, POLLIN | POLLOUT, &finish);
|
if (res <= 0) {
|
res = -1;
|
}
|
}
|
done:
|
fcntl(sock, F_SETFL, origflags);
|
LOG(INFO) << __func__ << ": " << sock << " connect_with_const timeout returning " << res;
|
return res;
|
}
|
|
static int retrying_poll(const int sock, const short events, const struct timespec* finish) {
|
struct timespec now, timeout;
|
|
retry:
|
LOG(INFO) << __func__ << ": " << sock << " retrying_poll";
|
|
now = evNowTime();
|
if (evCmpTime(*finish, now) > 0)
|
timeout = evSubTime(*finish, now);
|
else
|
timeout = evConsTime(0L, 0L);
|
struct pollfd fds = {.fd = sock, .events = events};
|
int n = ppoll(&fds, 1, &timeout, /*sigmask=*/NULL);
|
if (n == 0) {
|
LOG(INFO) << __func__ << ": " << sock << "retrying_poll timeout";
|
errno = ETIMEDOUT;
|
return 0;
|
}
|
if (n < 0) {
|
if (errno == EINTR) goto retry;
|
PLOG(INFO) << __func__ << ": " << sock << " retrying_poll failed";
|
return n;
|
}
|
if (fds.revents & (POLLIN | POLLOUT | POLLERR)) {
|
int error;
|
socklen_t len = sizeof(error);
|
if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &error, &len) < 0 || error) {
|
errno = error;
|
PLOG(INFO) << __func__ << ": " << sock << " retrying_poll getsockopt failed";
|
return -1;
|
}
|
}
|
LOG(INFO) << __func__ << ": " << sock << " retrying_poll returning " << n;
|
return n;
|
}
|
|
static int send_dg(res_state statp, res_params* params, const u_char* buf, int buflen, u_char* ans,
|
int anssiz, int* terrno, int ns, int* v_circuit, int* gotsomewhere, time_t* at,
|
int* rcode, int* delay) {
|
*at = time(NULL);
|
*delay = 0;
|
const HEADER* hp = (const HEADER*) (const void*) buf;
|
HEADER* anhp = (HEADER*) (void*) ans;
|
const struct sockaddr* nsap;
|
int nsaplen;
|
struct timespec now, timeout, finish, done;
|
struct sockaddr_storage from;
|
socklen_t fromlen;
|
int resplen, n, s;
|
|
nsap = get_nsaddr(statp, (size_t) ns);
|
nsaplen = get_salen(nsap);
|
if (statp->_u._ext.nssocks[ns] == -1) {
|
statp->_u._ext.nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
|
if (statp->_u._ext.nssocks[ns] < 0) {
|
switch (errno) {
|
case EPROTONOSUPPORT:
|
case EPFNOSUPPORT:
|
case EAFNOSUPPORT:
|
Perror(statp, "socket(dg)", errno);
|
return (0);
|
default:
|
*terrno = errno;
|
Perror(statp, "socket(dg)", errno);
|
return (-1);
|
}
|
}
|
|
fchown(statp->_u._ext.nssocks[ns], AID_DNS, -1);
|
if (statp->_mark != MARK_UNSET) {
|
if (setsockopt(statp->_u._ext.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(statp->_u._ext.nssocks[ns], nsap->sa_family) < 0) {
|
Aerror(statp, "bind(dg)", errno, nsap, nsaplen);
|
res_nclose(statp);
|
return (0);
|
}
|
if (connect(statp->_u._ext.nssocks[ns], nsap, (socklen_t) nsaplen) < 0) {
|
Aerror(statp, "connect(dg)", errno, nsap, nsaplen);
|
res_nclose(statp);
|
return (0);
|
}
|
#endif /* !CANNOT_CONNECT_DGRAM */
|
LOG(DEBUG) << __func__ << ": new DG socket";
|
}
|
s = statp->_u._ext.nssocks[ns];
|
#ifndef CANNOT_CONNECT_DGRAM
|
if (send(s, (const char*) buf, (size_t) buflen, 0) != buflen) {
|
Perror(statp, "send", errno);
|
res_nclose(statp);
|
return 0;
|
}
|
#else /* !CANNOT_CONNECT_DGRAM */
|
if (sendto(s, (const char*) buf, buflen, 0, nsap, nsaplen) != buflen) {
|
Aerror(statp, "sendto", errno, nsap, nsaplen);
|
res_nclose(statp);
|
return 0;
|
}
|
#endif /* !CANNOT_CONNECT_DGRAM */
|
|
// Wait for reply.
|
timeout = get_timeout(statp, params, ns);
|
now = evNowTime();
|
finish = evAddTime(now, timeout);
|
retry:
|
n = retrying_poll(s, POLLIN, &finish);
|
|
if (n == 0) {
|
*rcode = RCODE_TIMEOUT;
|
LOG(DEBUG) << __func__ << ": timeout";
|
*gotsomewhere = 1;
|
return 0;
|
}
|
if (n < 0) {
|
Perror(statp, "poll", 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, "recvfrom", errno);
|
res_nclose(statp);
|
return 0;
|
}
|
*gotsomewhere = 1;
|
if (resplen < HFIXEDSZ) {
|
/*
|
* Undersized message.
|
*/
|
LOG(DEBUG) << __func__ << ": undersized: " << 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.
|
*/
|
LOG(DEBUG) << __func__ << ": old answer:";
|
res_pquery(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.
|
*/
|
LOG(DEBUG) << __func__ << ": not our server:";
|
res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
|
goto retry;
|
}
|
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.
|
*/
|
LOG(DEBUG) << __func__ << ": server rejected query with EDNS0:";
|
res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
|
/* record the error */
|
statp->_flags |= RES_F_EDNS0ERR;
|
res_nclose(statp);
|
return 0;
|
}
|
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.
|
*/
|
LOG(DEBUG) << __func__ << ": wrong query name:";
|
res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
|
goto retry;
|
}
|
done = evNowTime();
|
*delay = _res_stats_calculate_rtt(&done, &now);
|
if (anhp->rcode == SERVFAIL || anhp->rcode == NOTIMP || anhp->rcode == REFUSED) {
|
LOG(DEBUG) << __func__ << ": server rejected query:";
|
res_pquery(ans, (resplen > anssiz) ? anssiz : resplen);
|
res_nclose(statp);
|
*rcode = anhp->rcode;
|
return 0;
|
}
|
if (!(statp->options & RES_IGNTC) && anhp->tc) {
|
/*
|
* To get the rest of answer,
|
* use TCP with same server.
|
*/
|
LOG(DEBUG) << __func__ << ": truncated answer";
|
*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.
|
*/
|
if (resplen > 0) {
|
*rcode = anhp->rcode;
|
}
|
return resplen;
|
}
|
|
static void Aerror(const res_state statp, const char* string, int error,
|
const struct sockaddr* address, int alen) {
|
const int save = errno;
|
char hbuf[NI_MAXHOST];
|
char sbuf[NI_MAXSERV];
|
constexpr int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
|
|
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';
|
}
|
LOG(DEBUG) << __func__ << ": " << string << " ([" << hbuf << "]." << sbuf
|
<< "): " << strerror(error);
|
}
|
errno = save;
|
}
|
|
static void Perror(const res_state statp, const char* string, int error) {
|
if ((statp->options & RES_DEBUG) != 0U) {
|
LOG(DEBUG) << __func__ << ": " << string << ": " << strerror(error);
|
}
|
}
|
|
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;
|
}
|
}
|
|
static int res_tls_send(res_state statp, const Slice query, const Slice answer, int* rcode,
|
bool* fallback) {
|
int resplen = 0;
|
const unsigned netId = statp->netid;
|
const unsigned mark = statp->_mark;
|
|
PrivateDnsStatus privateDnsStatus = gPrivateDnsConfiguration.getStatus(netId);
|
|
if (privateDnsStatus.mode == PrivateDnsMode::OFF) {
|
*fallback = true;
|
return -1;
|
}
|
|
if (privateDnsStatus.validatedServers.empty()) {
|
if (privateDnsStatus.mode == PrivateDnsMode::OPPORTUNISTIC) {
|
*fallback = true;
|
return -1;
|
} else {
|
// Sleep and iterate some small number of times checking for the
|
// arrival of resolved and validated server IP addresses, instead
|
// of returning an immediate error.
|
// This is needed because as soon as a network becomes the default network, apps will
|
// send DNS queries on that network. If no servers have yet validated, and we do not
|
// block those queries, they would immediately fail, causing application-visible errors.
|
// Note that this can happen even before the network validates, since an unvalidated
|
// network can become the default network if no validated networks are available.
|
//
|
// TODO: see if there is a better way to address this problem, such as buffering the
|
// queries in a queue or only blocking queries for the first few seconds after a default
|
// network change.
|
for (int i = 0; i < 42; i++) {
|
std::this_thread::sleep_for(std::chrono::milliseconds(100));
|
if (!gPrivateDnsConfiguration.getStatus(netId).validatedServers.empty()) {
|
privateDnsStatus = gPrivateDnsConfiguration.getStatus(netId);
|
break;
|
}
|
}
|
if (privateDnsStatus.validatedServers.empty()) {
|
return -1;
|
}
|
}
|
}
|
|
LOG(INFO) << __func__ << ": performing query over TLS";
|
|
const auto response = sDnsTlsDispatcher.query(privateDnsStatus.validatedServers, mark, query,
|
answer, &resplen);
|
|
LOG(INFO) << __func__ << ": TLS query result: " << static_cast<int>(response);
|
|
if (privateDnsStatus.mode == PrivateDnsMode::OPPORTUNISTIC) {
|
// In opportunistic mode, handle falling back to cleartext in some
|
// cases (DNS shouldn't fail if a validated opportunistic mode server
|
// becomes unreachable for some reason).
|
switch (response) {
|
case DnsTlsTransport::Response::success:
|
*rcode = reinterpret_cast<HEADER*>(answer.base())->rcode;
|
return resplen;
|
case DnsTlsTransport::Response::network_error:
|
// No need to set the error timeout here since it will fallback to UDP.
|
case DnsTlsTransport::Response::internal_error:
|
// Note: this will cause cleartext queries to be emitted, with
|
// all of the EDNS0 goodness enabled. Fingers crossed. :-/
|
*fallback = true;
|
[[fallthrough]];
|
default:
|
return -1;
|
}
|
} else {
|
// Strict mode
|
switch (response) {
|
case DnsTlsTransport::Response::success:
|
*rcode = reinterpret_cast<HEADER*>(answer.base())->rcode;
|
return resplen;
|
case DnsTlsTransport::Response::network_error:
|
// This case happens when the query stored in DnsTlsTransport is expired since
|
// either 1) the query has been tried for 3 times but no response or 2) fail to
|
// establish the connection with the server.
|
*rcode = RCODE_TIMEOUT;
|
[[fallthrough]];
|
default:
|
return -1;
|
}
|
}
|
}
|
|
int resolv_res_nsend(const android_net_context* netContext, const uint8_t* msg, int msgLen,
|
uint8_t* ans, int ansLen, int* rcode, uint32_t flags) {
|
res_state res = res_get_state();
|
res_setnetcontext(res, netContext);
|
_resolv_populate_res_for_net(res);
|
*rcode = NOERROR;
|
return res_nsend(res, msg, msgLen, ans, ansLen, rcode, flags);
|
}
|
