| /* $NetBSD: res_send.c,v 1.9 2006/01/24 17:41:25 christos Exp $ */ |
| |
| /* |
| * 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. |
| */ |
| |
| /* |
| * Send query to name server and wait for reply. |
| */ |
| |
| #define LOG_TAG "resolv" |
| |
| #include <sys/param.h> |
| #include <sys/socket.h> |
| #include <sys/time.h> |
| #include <sys/uio.h> |
| |
| #include <arpa/inet.h> |
| #include <arpa/nameser.h> |
| #include <netinet/in.h> |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <netdb.h> |
| #include <poll.h> |
| #include <signal.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <time.h> |
| #include <unistd.h> |
| |
| #include <android-base/logging.h> |
| #include <android/multinetwork.h> // ResNsendFlags |
| |
| #include <netdutils/Slice.h> |
| #include <netdutils/Stopwatch.h> |
| #include "DnsTlsDispatcher.h" |
| #include "DnsTlsTransport.h" |
| #include "PrivateDnsConfiguration.h" |
| #include "netd_resolv/resolv.h" |
| #include "netd_resolv/stats.h" |
| #include "private/android_filesystem_config.h" |
| #include "res_debug.h" |
| #include "resolv_cache.h" |
| #include "stats.pb.h" |
| |
| // TODO: use the namespace something like android::netd_resolv for libnetd_resolv |
| using android::net::CacheStatus; |
| using android::net::DnsQueryEvent; |
| using android::net::DnsTlsDispatcher; |
| using android::net::DnsTlsTransport; |
| using android::net::gPrivateDnsConfiguration; |
| using android::net::IpVersion; |
| using android::net::IV_IPV4; |
| using android::net::IV_IPV6; |
| using android::net::IV_UNKNOWN; |
| using android::net::NetworkDnsEventReported; |
| using android::net::NS_T_INVALID; |
| using android::net::NsRcode; |
| using android::net::NsType; |
| using android::net::PrivateDnsMode; |
| using android::net::PrivateDnsModes; |
| using android::net::PrivateDnsStatus; |
| using android::net::PROTO_TCP; |
| using android::net::PROTO_UDP; |
| using android::netdutils::Slice; |
| using android::netdutils::Stopwatch; |
| |
| static DnsTlsDispatcher sDnsTlsDispatcher; |
| |
| static int get_salen(const struct sockaddr*); |
| static struct sockaddr* get_nsaddr(res_state, size_t); |
| static int send_vc(res_state, res_params* params, const uint8_t*, int, uint8_t*, int, int*, int, |
| time_t*, int*, int*); |
| static int send_dg(res_state, res_params* params, const uint8_t*, int, uint8_t*, int, int*, int, |
| int*, int*, time_t*, int*, int*); |
| static void dump_error(const char*, const struct sockaddr*, int); |
| |
| static int sock_eq(struct sockaddr*, struct sockaddr*); |
| static int connect_with_timeout(int sock, const struct sockaddr* nsap, socklen_t salen, |
| const struct timespec timeout); |
| static int retrying_poll(const int sock, short events, const struct timespec* finish); |
| static int res_tls_send(res_state, const Slice query, const Slice answer, int* rcode, |
| bool* fallback); |
| |
| NsType getQueryType(const uint8_t* msg, size_t msgLen) { |
| ns_msg handle; |
| ns_rr rr; |
| if (ns_initparse((const uint8_t*)msg, msgLen, &handle) < 0 || |
| ns_parserr(&handle, ns_s_qd, 0, &rr) < 0) { |
| return NS_T_INVALID; |
| } |
| return static_cast<NsType>(ns_rr_type(rr)); |
| } |
| |
| IpVersion ipFamilyToIPVersion(const int ipFamily) { |
| switch (ipFamily) { |
| case AF_INET: |
| return IV_IPV4; |
| case AF_INET6: |
| return IV_IPV6; |
| default: |
| return IV_UNKNOWN; |
| } |
| } |
| |
| // BEGIN: Code copied from ISC eventlib |
| // TODO: move away from this code |
| #define BILLION 1000000000 |
| |
| static struct timespec evConsTime(time_t sec, long nsec) { |
| struct timespec x; |
| |
| x.tv_sec = sec; |
| x.tv_nsec = nsec; |
| return (x); |
| } |
| |
| static struct timespec evAddTime(struct timespec addend1, struct timespec addend2) { |
| struct timespec x; |
| |
| x.tv_sec = addend1.tv_sec + addend2.tv_sec; |
| x.tv_nsec = addend1.tv_nsec + addend2.tv_nsec; |
| if (x.tv_nsec >= BILLION) { |
| x.tv_sec++; |
| x.tv_nsec -= BILLION; |
| } |
| return (x); |
| } |
| |
| static struct timespec evSubTime(struct timespec minuend, struct timespec subtrahend) { |
| struct timespec x; |
| |
| x.tv_sec = minuend.tv_sec - subtrahend.tv_sec; |
| if (minuend.tv_nsec >= subtrahend.tv_nsec) |
| x.tv_nsec = minuend.tv_nsec - subtrahend.tv_nsec; |
| else { |
| x.tv_nsec = BILLION - subtrahend.tv_nsec + minuend.tv_nsec; |
| x.tv_sec--; |
| } |
| return (x); |
| } |
| |
| static int evCmpTime(struct timespec a, struct timespec b) { |
| #define SGN(x) ((x) < 0 ? (-1) : (x) > 0 ? (1) : (0)); |
| time_t s = a.tv_sec - b.tv_sec; |
| long n; |
| |
| if (s != 0) return SGN(s); |
| |
| n = a.tv_nsec - b.tv_nsec; |
| return SGN(n); |
| } |
| |
| static struct timespec evNowTime(void) { |
| struct timespec tsnow; |
| clock_gettime(CLOCK_REALTIME, &tsnow); |
| return tsnow; |
| } |
| |
| static struct iovec evConsIovec(void* buf, size_t cnt) { |
| struct iovec ret; |
| |
| memset(&ret, 0xf5, sizeof ret); |
| ret.iov_base = buf; |
| ret.iov_len = cnt; |
| return ret; |
| } |
| |
| // END: Code copied from ISC eventlib |
| |
| /* BIONIC-BEGIN: implement source port randomization */ |
| 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 + (arc4random_uniform(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 attempts, 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 */ |
| |
| // Disables all nameservers other than selectedServer |
| static void res_set_usable_server(int selectedServer, int nscount, bool usable_servers[]) { |
| int usableIndex = 0; |
| for (int ns = 0; ns < nscount; ns++) { |
| if (usable_servers[ns]) ++usableIndex; |
| if (usableIndex != selectedServer) usable_servers[ns] = false; |
| } |
| } |
| |
| // Looks up the nameserver address in res.nsaddrs[], returns true if found, otherwise false. |
| static bool res_ourserver_p(res_state statp, const sockaddr* sa) { |
| const sockaddr_in *inp, *srv; |
| const 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 true; |
| } |
| break; |
| case AF_INET6: |
| 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 true; |
| } |
| break; |
| default: |
| break; |
| } |
| return false; |
| } |
| |
| /* int |
| * res_nameinquery(name, type, cl, buf, eom) |
| * look for (name, type, cl) 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 cl, const uint8_t* buf, const uint8_t* eom) { |
| const uint8_t* cp = buf + HFIXEDSZ; |
| int qdcount = ntohs(((const HEADER*) (const void*) buf)->qdcount); |
| |
| while (qdcount-- > 0) { |
| char tname[MAXDNAME + 1]; |
| int n = dn_expand(buf, eom, cp, tname, sizeof tname); |
| if (n < 0) return (-1); |
| cp += n; |
| if (cp + 2 * INT16SZ > eom) return (-1); |
| int ttype = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; |
| int tclass = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; |
| if (ttype == type && tclass == cl && 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 uint8_t* buf1, const uint8_t* eom1, const uint8_t* buf2, |
| const uint8_t* eom2) { |
| const uint8_t* 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 = dn_expand(buf1, eom1, cp, tname, sizeof tname); |
| if (n < 0) return (-1); |
| cp += n; |
| if (cp + 2 * INT16SZ > eom1) return (-1); |
| int ttype = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; |
| int tclass = ntohs(*reinterpret_cast<const uint16_t*>(cp)); |
| cp += INT16SZ; |
| if (!res_nameinquery(tname, ttype, tclass, buf2, eom2)) return (0); |
| } |
| return (1); |
| } |
| |
| static DnsQueryEvent* addDnsQueryEvent(NetworkDnsEventReported* event) { |
| return event->mutable_dns_query_events()->add_dns_query_event(); |
| } |
| |
| int res_nsend(res_state statp, const uint8_t* buf, int buflen, uint8_t* ans, int anssiz, int* rcode, |
| uint32_t flags) { |
| int gotsomewhere, terrno, v_circuit, resplen, n; |
| ResolvCacheStatus cache_status = RESOLV_CACHE_UNSUPPORTED; |
| |
| if (anssiz < HFIXEDSZ) { |
| // TODO: Remove errno once callers stop using it |
| errno = EINVAL; |
| return -EINVAL; |
| } |
| LOG(DEBUG) << __func__; |
| res_pquery(buf, buflen); |
| |
| v_circuit = buflen > PACKETSZ; |
| gotsomewhere = 0; |
| terrno = ETIMEDOUT; |
| |
| int anslen = 0; |
| Stopwatch cacheStopwatch; |
| cache_status = resolv_cache_lookup(statp->netid, buf, buflen, ans, anssiz, &anslen, flags); |
| const int32_t cacheLatencyUs = saturate_cast<int32_t>(cacheStopwatch.timeTakenUs()); |
| if (cache_status == RESOLV_CACHE_FOUND) { |
| HEADER* hp = (HEADER*)(void*)ans; |
| *rcode = hp->rcode; |
| DnsQueryEvent* dnsQueryEvent = addDnsQueryEvent(statp->event); |
| dnsQueryEvent->set_latency_micros(cacheLatencyUs); |
| dnsQueryEvent->set_cache_hit(static_cast<CacheStatus>(cache_status)); |
| 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) { |
| // We have no nameservers configured, so there's no point trying. |
| // Tell the cache the query failed, or any retries and anyone else asking the same |
| // question will block for PENDING_REQUEST_TIMEOUT seconds instead of failing fast. |
| _resolv_cache_query_failed(statp->netid, buf, buflen, flags); |
| |
| // TODO: Remove errno once callers stop using it |
| errno = ESRCH; |
| return -ESRCH; |
| } |
| |
| res_stats stats[MAXNS]; |
| res_params params; |
| int revision_id = resolv_cache_get_resolver_stats(statp->netid, ¶ms, stats); |
| if (revision_id < 0) { |
| // 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); |
| |
| // 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; |
| int nsaplen; |
| time_t now = 0; |
| int delay = 0; |
| *rcode = RCODE_INTERNAL_ERROR; |
| const sockaddr* nsap = get_nsaddr(statp, 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->netcontext_flags & NET_CONTEXT_FLAG_USE_LOCAL_NAMESERVERS)) { |
| bool fallback = false; |
| resplen = res_tls_send(statp, Slice(const_cast<uint8_t*>(buf), buflen), |
| Slice(ans, anssiz), rcode, &fallback); |
| if (resplen > 0) { |
| LOG(DEBUG) << __func__ << ": got answer from DoT"; |
| res_pquery(ans, resplen); |
| 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; |
| } |
| } |
| |
| static const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; |
| char abuf[NI_MAXHOST]; |
| DnsQueryEvent* dnsQueryEvent = addDnsQueryEvent(statp->event); |
| dnsQueryEvent->set_cache_hit(static_cast<CacheStatus>(cache_status)); |
| |
| if (getnameinfo(nsap, (socklen_t)nsaplen, abuf, sizeof(abuf), NULL, 0, niflags) == 0) |
| LOG(DEBUG) << __func__ << ": Querying server (# " << ns + 1 |
| << ") address = " << abuf; |
| |
| Stopwatch queryStopwatch; |
| 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); |
| |
| dnsQueryEvent->set_latency_micros( |
| saturate_cast<int32_t>(queryStopwatch.timeTakenUs())); |
| dnsQueryEvent->set_dns_server_index(ns); |
| dnsQueryEvent->set_ip_version(ipFamilyToIPVersion(nsap->sa_family)); |
| dnsQueryEvent->set_retry_times(attempt); |
| dnsQueryEvent->set_rcode(static_cast<NsRcode>(*rcode)); |
| dnsQueryEvent->set_protocol(PROTO_TCP); |
| dnsQueryEvent->set_type(getQueryType(buf, buflen)); |
| |
| /* |
| * 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); |
| |
| dnsQueryEvent->set_latency_micros( |
| saturate_cast<int32_t>(queryStopwatch.timeTakenUs())); |
| dnsQueryEvent->set_dns_server_index(ns); |
| dnsQueryEvent->set_ip_version(ipFamilyToIPVersion(nsap->sa_family)); |
| dnsQueryEvent->set_retry_times(attempt); |
| dnsQueryEvent->set_rcode(static_cast<NsRcode>(*rcode)); |
| dnsQueryEvent->set_protocol(PROTO_UDP); |
| dnsQueryEvent->set_type(getQueryType(buf, buflen)); |
| |
| /* 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); |
| } |
| 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 */ |
| } |
| |
| static struct sockaddr* get_nsaddr(res_state statp, size_t n) { |
| return (struct sockaddr*)(void*)&statp->nsaddrs[n]; |
| } |
| |
| static struct timespec get_timeout(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 uint8_t* buf, int buflen, |
| uint8_t* 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]; |
| uint8_t* 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: |
| PLOG(DEBUG) << __func__ << ": socket(vc): "; |
| return 0; |
| default: |
| *terrno = errno; |
| PLOG(DEBUG) << __func__ << ": socket(vc): "; |
| return -1; |
| } |
| } |
| resolv_tag_socket(statp->_vcsock, statp->uid); |
| if (statp->_mark != MARK_UNSET) { |
| if (setsockopt(statp->_vcsock, SOL_SOCKET, SO_MARK, &statp->_mark, |
| sizeof(statp->_mark)) < 0) { |
| *terrno = errno; |
| PLOG(DEBUG) << __func__ << ": setsockopt: "; |
| return -1; |
| } |
| } |
| errno = 0; |
| if (random_bind(statp->_vcsock, nsap->sa_family) < 0) { |
| *terrno = errno; |
| dump_error("bind/vc", 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; |
| dump_error("connect/vc", 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; |
| PLOG(DEBUG) << __func__ << ": write failed: "; |
| 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; |
| PLOG(DEBUG) << __func__ << ": read failed: "; |
| 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; |
| PLOG(DEBUG) << __func__ << ": read(vc): "; |
| 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 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 > anssiz) ? anssiz : 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 uint8_t* buf, int buflen, |
| uint8_t* 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->nssocks[ns] == -1) { |
| statp->nssocks[ns] = socket(nsap->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, 0); |
| if (statp->nssocks[ns] < 0) { |
| switch (errno) { |
| case EPROTONOSUPPORT: |
| case EPFNOSUPPORT: |
| case EAFNOSUPPORT: |
| PLOG(DEBUG) << __func__ << ": socket(dg): "; |
| return (0); |
| default: |
| *terrno = errno; |
| PLOG(DEBUG) << __func__ << ": socket(dg): "; |
| return (-1); |
| } |
| } |
| |
| resolv_tag_socket(statp->nssocks[ns], statp->uid); |
| if (statp->_mark != MARK_UNSET) { |
| if (setsockopt(statp->nssocks[ns], SOL_SOCKET, SO_MARK, &(statp->_mark), |
| sizeof(statp->_mark)) < 0) { |
| res_nclose(statp); |
| return -1; |
| } |
| } |
| // Use a "connected" datagram socket to receive an ECONNREFUSED error |
| // on the next socket operation when the server responds with an |
| // ICMP port-unreachable error. This way we can detect the absence of |
| // a nameserver without timing out. |
| if (random_bind(statp->nssocks[ns], nsap->sa_family) < 0) { |
| dump_error("bind(dg)", nsap, nsaplen); |
| res_nclose(statp); |
| return (0); |
| } |
| if (connect(statp->nssocks[ns], nsap, (socklen_t)nsaplen) < 0) { |
| dump_error("connect(dg)", nsap, nsaplen); |
| res_nclose(statp); |
| return (0); |
| } |
| LOG(DEBUG) << __func__ << ": new DG socket"; |
| } |
| s = statp->nssocks[ns]; |
| if (send(s, (const char*) buf, (size_t) buflen, 0) != buflen) { |
| PLOG(DEBUG) << __func__ << ": send: "; |
| res_nclose(statp); |
| return 0; |
| } |
| |
| // 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) { |
| PLOG(DEBUG) << __func__ << ": poll: "; |
| 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) { |
| PLOG(DEBUG) << __func__ << ": recvfrom: "; |
| 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 (!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->netcontext_flags & NET_CONTEXT_FLAG_USE_EDNS)) { |
| /* |
| * 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 (!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 (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 dump_error(const char* str, const struct sockaddr* address, int alen) { |
| char hbuf[NI_MAXHOST]; |
| char sbuf[NI_MAXSERV]; |
| constexpr int niflags = NI_NUMERICHOST | NI_NUMERICSERV; |
| |
| if (!WOULD_LOG(DEBUG)) return; |
| |
| 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'; |
| } |
| PLOG(DEBUG) << __func__ << ": " << str << " ([" << hbuf << "]." << sbuf << "): "; |
| } |
| |
| 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; |
| } |
| } |
| |
| PrivateDnsModes convertEnumType(PrivateDnsMode privateDnsmode) { |
| switch (privateDnsmode) { |
| case PrivateDnsMode::OFF: |
| return PrivateDnsModes::PDM_OFF; |
| case PrivateDnsMode::OPPORTUNISTIC: |
| return PrivateDnsModes::PDM_OPPORTUNISTIC; |
| case PrivateDnsMode::STRICT: |
| return PrivateDnsModes::PDM_STRICT; |
| } |
| return PrivateDnsModes::PDM_UNKNOWN; |
| } |
| |
| 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; |
| |
| PrivateDnsStatus privateDnsStatus = gPrivateDnsConfiguration.getStatus(netId); |
| statp->event->set_private_dns_modes(convertEnumType(privateDnsStatus.mode)); |
| |
| 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)); |
| // Calling getStatus() to merely check if there's any validated server seems |
| // wasteful. Consider adding a new method in PrivateDnsConfiguration for speed ups. |
| 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(), statp, 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, |
| NetworkDnsEventReported* event) { |
| assert(event != nullptr); |
| res_state res = res_get_state(); |
| res_setnetcontext(res, netContext, event); |
| _resolv_populate_res_for_net(res); |
| *rcode = NOERROR; |
| return res_nsend(res, msg, msgLen, ans, ansLen, rcode, flags); |
| } |