1953 lines
62 KiB
C++
1953 lines
62 KiB
C++
/* $NetBSD: getaddrinfo.c,v 1.82 2006/03/25 12:09:40 rpaulo Exp $ */
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/* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */
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/*
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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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#define LOG_TAG "resolv"
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#include "getaddrinfo.h"
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#include <arpa/inet.h>
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#include <arpa/nameser.h>
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#include <assert.h>
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <net/if.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <stdbool.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/un.h>
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#include <unistd.h>
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#include <chrono>
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#include <future>
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#include <android-base/logging.h>
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#include "Experiments.h"
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#include "netd_resolv/resolv.h"
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#include "res_comp.h"
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#include "res_debug.h"
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#include "resolv_cache.h"
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#include "resolv_private.h"
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#include "util.h"
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#define ANY 0
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using android::net::NetworkDnsEventReported;
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const char in_addrany[] = {0, 0, 0, 0};
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const char in_loopback[] = {127, 0, 0, 1};
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const char in6_addrany[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
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const char in6_loopback[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1};
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const struct afd {
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int a_af;
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int a_addrlen;
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int a_socklen;
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int a_off;
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const char* a_addrany;
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const char* a_loopback;
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int a_scoped;
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} afdl[] = {
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{PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6),
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offsetof(struct sockaddr_in6, sin6_addr), in6_addrany, in6_loopback, 1},
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{PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in),
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offsetof(struct sockaddr_in, sin_addr), in_addrany, in_loopback, 0},
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{0, 0, 0, 0, NULL, NULL, 0},
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};
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struct Explore {
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int e_af;
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int e_socktype;
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int e_protocol;
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int e_wild;
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#define WILD_AF(ex) ((ex).e_wild & 0x01)
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#define WILD_SOCKTYPE(ex) ((ex).e_wild & 0x02)
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#define WILD_PROTOCOL(ex) ((ex).e_wild & 0x04)
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};
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const Explore explore_options[] = {
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{PF_INET6, SOCK_DGRAM, IPPROTO_UDP, 0x07},
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{PF_INET6, SOCK_STREAM, IPPROTO_TCP, 0x07},
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{PF_INET6, SOCK_RAW, ANY, 0x05},
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{PF_INET, SOCK_DGRAM, IPPROTO_UDP, 0x07},
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{PF_INET, SOCK_STREAM, IPPROTO_TCP, 0x07},
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{PF_INET, SOCK_RAW, ANY, 0x05},
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{PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, 0x07},
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{PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, 0x07},
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{PF_UNSPEC, SOCK_RAW, ANY, 0x05},
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};
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#define PTON_MAX 16
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struct res_target {
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struct res_target* next;
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const char* name; // domain name
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int qclass, qtype; // class and type of query
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std::vector<uint8_t> answer = std::vector<uint8_t>(MAXPACKET, 0); // buffer to put answer
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int n = 0; // result length
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};
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static int str2number(const char*);
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static int explore_fqdn(const struct addrinfo*, const char*, const char*, struct addrinfo**,
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const struct android_net_context*, NetworkDnsEventReported* event);
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static int explore_null(const struct addrinfo*, const char*, struct addrinfo**);
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static int explore_numeric(const struct addrinfo*, const char*, const char*, struct addrinfo**,
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const char*);
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static int explore_numeric_scope(const struct addrinfo*, const char*, const char*,
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struct addrinfo**);
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static int get_canonname(const struct addrinfo*, struct addrinfo*, const char*);
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static struct addrinfo* get_ai(const struct addrinfo*, const struct afd*, const char*);
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static int get_portmatch(const struct addrinfo*, const char*);
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static int get_port(const struct addrinfo*, const char*, int);
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static const struct afd* find_afd(int);
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static int ip6_str2scopeid(const char*, struct sockaddr_in6*, uint32_t*);
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static struct addrinfo* getanswer(const std::vector<uint8_t>&, int, const char*, int,
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const struct addrinfo*, int* herrno);
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static int dns_getaddrinfo(const char* name, const addrinfo* pai,
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const android_net_context* netcontext, addrinfo** rv,
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NetworkDnsEventReported* event);
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static void _sethtent(FILE**);
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static void _endhtent(FILE**);
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static struct addrinfo* _gethtent(FILE**, const char*, const struct addrinfo*);
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static struct addrinfo* getCustomHosts(const size_t netid, const char*, const struct addrinfo*);
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static bool files_getaddrinfo(const size_t netid, const char* name, const addrinfo* pai,
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addrinfo** res);
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static int _find_src_addr(const struct sockaddr*, struct sockaddr*, unsigned, uid_t);
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static int res_queryN(const char* name, res_target* target, ResState* res, int* herrno);
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static int res_searchN(const char* name, res_target* target, ResState* res, int* herrno);
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static int res_querydomainN(const char* name, const char* domain, res_target* target, ResState* res,
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int* herrno);
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const char* const ai_errlist[] = {
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"Success",
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"Address family for hostname not supported", /* EAI_ADDRFAMILY */
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"Temporary failure in name resolution", /* EAI_AGAIN */
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"Invalid value for ai_flags", /* EAI_BADFLAGS */
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"Non-recoverable failure in name resolution", /* EAI_FAIL */
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"ai_family not supported", /* EAI_FAMILY */
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"Memory allocation failure", /* EAI_MEMORY */
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"No address associated with hostname", /* EAI_NODATA */
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"hostname nor servname provided, or not known", /* EAI_NONAME */
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"servname not supported for ai_socktype", /* EAI_SERVICE */
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"ai_socktype not supported", /* EAI_SOCKTYPE */
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"System error returned in errno", /* EAI_SYSTEM */
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"Invalid value for hints", /* EAI_BADHINTS */
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"Resolved protocol is unknown", /* EAI_PROTOCOL */
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"Argument buffer overflow", /* EAI_OVERFLOW */
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"Unknown error", /* EAI_MAX */
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};
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/* XXX macros that make external reference is BAD. */
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#define GET_AI(ai, afd, addr) \
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do { \
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/* external reference: pai, error, and label free */ \
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(ai) = get_ai(pai, (afd), (addr)); \
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if ((ai) == NULL) { \
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error = EAI_MEMORY; \
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goto free; \
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} \
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} while (0)
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#define GET_PORT(ai, serv) \
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do { \
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/* external reference: error and label free */ \
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error = get_port((ai), (serv), 0); \
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if (error != 0) goto free; \
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} while (0)
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#define MATCH_FAMILY(x, y, w) \
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((x) == (y) || ((w) && ((x) == PF_UNSPEC || (y) == PF_UNSPEC)))
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#define MATCH(x, y, w) ((x) == (y) || ((w) && ((x) == ANY || (y) == ANY)))
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const char* gai_strerror(int ecode) {
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if (ecode < 0 || ecode > EAI_MAX) ecode = EAI_MAX;
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return ai_errlist[ecode];
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}
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void freeaddrinfo(struct addrinfo* ai) {
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while (ai) {
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struct addrinfo* next = ai->ai_next;
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if (ai->ai_canonname) free(ai->ai_canonname);
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// Also frees ai->ai_addr which points to extra space beyond addrinfo
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free(ai);
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ai = next;
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}
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}
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static int str2number(const char* p) {
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char* ep;
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unsigned long v;
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assert(p != NULL);
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if (*p == '\0') return -1;
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ep = NULL;
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errno = 0;
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v = strtoul(p, &ep, 10);
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if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX)
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return v;
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else
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return -1;
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}
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/*
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* The following functions determine whether IPv4 or IPv6 connectivity is
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* available in order to implement AI_ADDRCONFIG.
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*
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* Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is
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* available, but whether addresses of the specified family are "configured
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* on the local system". However, bionic doesn't currently support getifaddrs,
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* so checking for connectivity is the next best thing.
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*/
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static int have_ipv6(unsigned mark, uid_t uid) {
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static const struct sockaddr_in6 sin6_test = {
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.sin6_family = AF_INET6,
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.sin6_addr.s6_addr = {// 2000::
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0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};
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sockaddr_union addr = {.sin6 = sin6_test};
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return _find_src_addr(&addr.sa, NULL, mark, uid) == 1;
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}
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static int have_ipv4(unsigned mark, uid_t uid) {
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static const struct sockaddr_in sin_test = {
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.sin_family = AF_INET,
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.sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8
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};
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sockaddr_union addr = {.sin = sin_test};
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return _find_src_addr(&addr.sa, NULL, mark, uid) == 1;
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}
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// Internal version of getaddrinfo(), but limited to AI_NUMERICHOST.
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// NOTE: also called by resolv_set_nameservers().
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int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hints,
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addrinfo** result) {
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hints.ai_flags = AI_NUMERICHOST;
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const android_net_context netcontext = {
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.app_netid = NETID_UNSET,
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.app_mark = MARK_UNSET,
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.dns_netid = NETID_UNSET,
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.dns_mark = MARK_UNSET,
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.uid = NET_CONTEXT_INVALID_UID,
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.pid = NET_CONTEXT_INVALID_PID,
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};
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NetworkDnsEventReported event;
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return android_getaddrinfofornetcontext(hostname, servname, &hints, &netcontext, result,
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&event);
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}
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namespace {
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int validateHints(const addrinfo* _Nonnull hints) {
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if (!hints) return EAI_BADHINTS;
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// error check for hints
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if (hints->ai_addrlen || hints->ai_canonname || hints->ai_addr || hints->ai_next) {
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return EAI_BADHINTS;
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}
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if (hints->ai_flags & ~AI_MASK) {
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return EAI_BADFLAGS;
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}
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if (!(hints->ai_family == PF_UNSPEC || hints->ai_family == PF_INET ||
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hints->ai_family == PF_INET6)) {
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return EAI_FAMILY;
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}
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// Socket types which are not in explore_options.
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switch (hints->ai_socktype) {
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case SOCK_RAW:
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case SOCK_DGRAM:
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case SOCK_STREAM:
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case ANY:
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break;
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default:
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return EAI_SOCKTYPE;
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}
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if (hints->ai_socktype == ANY || hints->ai_protocol == ANY) return 0;
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// if both socktype/protocol are specified, check if they are meaningful combination.
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for (const Explore& ex : explore_options) {
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if (hints->ai_family != ex.e_af) continue;
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if (ex.e_socktype == ANY) continue;
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if (ex.e_protocol == ANY) continue;
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if (hints->ai_socktype == ex.e_socktype && hints->ai_protocol != ex.e_protocol) {
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return EAI_BADHINTS;
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}
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}
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return 0;
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}
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} // namespace
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int android_getaddrinfofornetcontext(const char* hostname, const char* servname,
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const addrinfo* hints, const android_net_context* netcontext,
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addrinfo** res, NetworkDnsEventReported* event) {
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// hostname is allowed to be nullptr
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// servname is allowed to be nullptr
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// hints is allowed to be nullptr
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assert(res != nullptr);
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assert(netcontext != nullptr);
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assert(event != nullptr);
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addrinfo sentinel = {};
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addrinfo* cur = &sentinel;
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int error = 0;
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do {
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if (hostname == nullptr && servname == nullptr) {
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error = EAI_NONAME;
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break;
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}
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if (hints && (error = validateHints(hints))) break;
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addrinfo ai = hints ? *hints : addrinfo{};
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// Check for special cases:
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// (1) numeric servname is disallowed if socktype/protocol are left unspecified.
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// (2) servname is disallowed for raw and other inet{,6} sockets.
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if (MATCH_FAMILY(ai.ai_family, PF_INET, 1) || MATCH_FAMILY(ai.ai_family, PF_INET6, 1)) {
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addrinfo tmp = ai;
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if (tmp.ai_family == PF_UNSPEC) {
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tmp.ai_family = PF_INET6;
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}
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error = get_portmatch(&tmp, servname);
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if (error) break;
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}
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// NULL hostname, or numeric hostname
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for (const Explore& ex : explore_options) {
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/* PF_UNSPEC entries are prepared for DNS queries only */
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if (ex.e_af == PF_UNSPEC) continue;
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if (!MATCH_FAMILY(ai.ai_family, ex.e_af, WILD_AF(ex))) continue;
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if (!MATCH(ai.ai_socktype, ex.e_socktype, WILD_SOCKTYPE(ex))) continue;
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if (!MATCH(ai.ai_protocol, ex.e_protocol, WILD_PROTOCOL(ex))) continue;
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addrinfo tmp = ai;
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if (tmp.ai_family == PF_UNSPEC) tmp.ai_family = ex.e_af;
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if (tmp.ai_socktype == ANY && ex.e_socktype != ANY) tmp.ai_socktype = ex.e_socktype;
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if (tmp.ai_protocol == ANY && ex.e_protocol != ANY) tmp.ai_protocol = ex.e_protocol;
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LOG(DEBUG) << __func__ << ": explore_numeric: ai_family=" << tmp.ai_family
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<< " ai_socktype=" << tmp.ai_socktype << " ai_protocol=" << tmp.ai_protocol;
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if (hostname == nullptr)
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error = explore_null(&tmp, servname, &cur->ai_next);
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else
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error = explore_numeric_scope(&tmp, hostname, servname, &cur->ai_next);
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if (error) break;
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while (cur->ai_next) cur = cur->ai_next;
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}
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if (error) break;
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// If numeric representation of AF1 can be interpreted as FQDN
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// representation of AF2, we need to think again about the code below.
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if (sentinel.ai_next) break;
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if (hostname == nullptr) {
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error = EAI_NODATA;
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break;
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}
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if (ai.ai_flags & AI_NUMERICHOST) {
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error = EAI_NONAME;
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break;
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}
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return resolv_getaddrinfo(hostname, servname, hints, netcontext, res, event);
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} while (0);
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if (error) {
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freeaddrinfo(sentinel.ai_next);
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*res = nullptr;
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} else {
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*res = sentinel.ai_next;
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}
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return error;
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}
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int resolv_getaddrinfo(const char* _Nonnull hostname, const char* servname, const addrinfo* hints,
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const android_net_context* _Nonnull netcontext, addrinfo** _Nonnull res,
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NetworkDnsEventReported* _Nonnull event) {
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if (hostname == nullptr && servname == nullptr) return EAI_NONAME;
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if (hostname == nullptr) return EAI_NODATA;
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// servname is allowed to be nullptr
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// hints is allowed to be nullptr
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assert(res != nullptr);
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assert(netcontext != nullptr);
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assert(event != nullptr);
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int error = EAI_FAIL;
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if (hints && (error = validateHints(hints))) {
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*res = nullptr;
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return error;
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}
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addrinfo ai = hints ? *hints : addrinfo{};
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addrinfo sentinel = {};
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addrinfo* cur = &sentinel;
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// hostname as alphanumeric name.
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// We would like to prefer AF_INET6 over AF_INET, so we'll make a outer loop by AFs.
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for (const Explore& ex : explore_options) {
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// Require exact match for family field
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if (ai.ai_family != ex.e_af) continue;
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if (!MATCH(ai.ai_socktype, ex.e_socktype, WILD_SOCKTYPE(ex))) continue;
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if (!MATCH(ai.ai_protocol, ex.e_protocol, WILD_PROTOCOL(ex))) continue;
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addrinfo tmp = ai;
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if (tmp.ai_socktype == ANY && ex.e_socktype != ANY) tmp.ai_socktype = ex.e_socktype;
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if (tmp.ai_protocol == ANY && ex.e_protocol != ANY) tmp.ai_protocol = ex.e_protocol;
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LOG(DEBUG) << __func__ << ": explore_fqdn(): ai_family=" << tmp.ai_family
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<< " ai_socktype=" << tmp.ai_socktype << " ai_protocol=" << tmp.ai_protocol;
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error = explore_fqdn(&tmp, hostname, servname, &cur->ai_next, netcontext, event);
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while (cur->ai_next) cur = cur->ai_next;
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}
|
|
|
|
// Propagate the last error from explore_fqdn(), but only when *all* attempts failed.
|
|
if ((*res = sentinel.ai_next)) return 0;
|
|
|
|
// TODO: consider removing freeaddrinfo.
|
|
freeaddrinfo(sentinel.ai_next);
|
|
*res = nullptr;
|
|
return (error == 0) ? EAI_FAIL : error;
|
|
}
|
|
|
|
// FQDN hostname, DNS lookup
|
|
static int explore_fqdn(const addrinfo* pai, const char* hostname, const char* servname,
|
|
addrinfo** res, const android_net_context* netcontext,
|
|
NetworkDnsEventReported* event) {
|
|
assert(pai != nullptr);
|
|
// hostname may be nullptr
|
|
// servname may be nullptr
|
|
assert(res != nullptr);
|
|
|
|
addrinfo* result = nullptr;
|
|
int error = 0;
|
|
|
|
// If the servname does not match socktype/protocol, return error code.
|
|
if ((error = get_portmatch(pai, servname))) return error;
|
|
|
|
if (!files_getaddrinfo(netcontext->dns_netid, hostname, pai, &result)) {
|
|
error = dns_getaddrinfo(hostname, pai, netcontext, &result, event);
|
|
}
|
|
if (error) {
|
|
freeaddrinfo(result);
|
|
return error;
|
|
}
|
|
|
|
for (addrinfo* cur = result; cur; cur = cur->ai_next) {
|
|
// canonname should be filled already
|
|
if ((error = get_port(cur, servname, 0))) {
|
|
freeaddrinfo(result);
|
|
return error;
|
|
}
|
|
}
|
|
*res = result;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* hostname == NULL.
|
|
* passive socket -> anyaddr (0.0.0.0 or ::)
|
|
* non-passive socket -> localhost (127.0.0.1 or ::1)
|
|
*/
|
|
static int explore_null(const struct addrinfo* pai, const char* servname, struct addrinfo** res) {
|
|
int s;
|
|
const struct afd* afd;
|
|
struct addrinfo* cur;
|
|
struct addrinfo sentinel;
|
|
int error;
|
|
|
|
LOG(DEBUG) << __func__;
|
|
|
|
assert(pai != NULL);
|
|
/* servname may be NULL */
|
|
assert(res != NULL);
|
|
|
|
*res = NULL;
|
|
sentinel.ai_next = NULL;
|
|
cur = &sentinel;
|
|
|
|
/*
|
|
* filter out AFs that are not supported by the kernel
|
|
* XXX errno?
|
|
*/
|
|
s = socket(pai->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, 0);
|
|
if (s < 0) {
|
|
if (errno != EMFILE) return 0;
|
|
} else
|
|
close(s);
|
|
|
|
/*
|
|
* if the servname does not match socktype/protocol, ignore it.
|
|
*/
|
|
if (get_portmatch(pai, servname) != 0) return 0;
|
|
|
|
afd = find_afd(pai->ai_family);
|
|
if (afd == NULL) return 0;
|
|
|
|
if (pai->ai_flags & AI_PASSIVE) {
|
|
GET_AI(cur->ai_next, afd, afd->a_addrany);
|
|
GET_PORT(cur->ai_next, servname);
|
|
} else {
|
|
GET_AI(cur->ai_next, afd, afd->a_loopback);
|
|
GET_PORT(cur->ai_next, servname);
|
|
}
|
|
cur = cur->ai_next;
|
|
|
|
*res = sentinel.ai_next;
|
|
return 0;
|
|
|
|
free:
|
|
freeaddrinfo(sentinel.ai_next);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* numeric hostname
|
|
*/
|
|
static int explore_numeric(const struct addrinfo* pai, const char* hostname, const char* servname,
|
|
struct addrinfo** res, const char* canonname) {
|
|
const struct afd* afd;
|
|
struct addrinfo* cur;
|
|
struct addrinfo sentinel;
|
|
int error;
|
|
char pton[PTON_MAX];
|
|
|
|
assert(pai != NULL);
|
|
/* hostname may be NULL */
|
|
/* servname may be NULL */
|
|
assert(res != NULL);
|
|
|
|
*res = NULL;
|
|
sentinel.ai_next = NULL;
|
|
cur = &sentinel;
|
|
|
|
/*
|
|
* if the servname does not match socktype/protocol, ignore it.
|
|
*/
|
|
if (get_portmatch(pai, servname) != 0) return 0;
|
|
|
|
afd = find_afd(pai->ai_family);
|
|
if (afd == NULL) return 0;
|
|
|
|
if (inet_pton(afd->a_af, hostname, pton) == 1) {
|
|
if (pai->ai_family == afd->a_af || pai->ai_family == PF_UNSPEC /*?*/) {
|
|
GET_AI(cur->ai_next, afd, pton);
|
|
GET_PORT(cur->ai_next, servname);
|
|
if ((pai->ai_flags & AI_CANONNAME)) {
|
|
/*
|
|
* Set the numeric address itself as
|
|
* the canonical name, based on a
|
|
* clarification in rfc2553bis-03.
|
|
*/
|
|
error = get_canonname(pai, cur->ai_next, canonname);
|
|
if (error != 0) {
|
|
freeaddrinfo(sentinel.ai_next);
|
|
return error;
|
|
}
|
|
}
|
|
while (cur->ai_next) cur = cur->ai_next;
|
|
} else
|
|
return EAI_FAMILY;
|
|
}
|
|
|
|
*res = sentinel.ai_next;
|
|
return 0;
|
|
|
|
free:
|
|
freeaddrinfo(sentinel.ai_next);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* numeric hostname with scope
|
|
*/
|
|
static int explore_numeric_scope(const struct addrinfo* pai, const char* hostname,
|
|
const char* servname, struct addrinfo** res) {
|
|
const struct afd* afd;
|
|
struct addrinfo* cur;
|
|
int error;
|
|
const char *cp, *scope, *addr;
|
|
struct sockaddr_in6* sin6;
|
|
|
|
LOG(DEBUG) << __func__;
|
|
|
|
assert(pai != NULL);
|
|
/* hostname may be NULL */
|
|
/* servname may be NULL */
|
|
assert(res != NULL);
|
|
|
|
/*
|
|
* if the servname does not match socktype/protocol, ignore it.
|
|
*/
|
|
if (get_portmatch(pai, servname) != 0) return 0;
|
|
|
|
afd = find_afd(pai->ai_family);
|
|
if (afd == NULL) return 0;
|
|
|
|
if (!afd->a_scoped) return explore_numeric(pai, hostname, servname, res, hostname);
|
|
|
|
cp = strchr(hostname, SCOPE_DELIMITER);
|
|
if (cp == NULL) return explore_numeric(pai, hostname, servname, res, hostname);
|
|
|
|
/*
|
|
* Handle special case of <scoped_address><delimiter><scope id>
|
|
*/
|
|
char* hostname2 = strdup(hostname);
|
|
if (hostname2 == NULL) return EAI_MEMORY;
|
|
/* terminate at the delimiter */
|
|
hostname2[cp - hostname] = '\0';
|
|
addr = hostname2;
|
|
scope = cp + 1;
|
|
|
|
error = explore_numeric(pai, addr, servname, res, hostname);
|
|
if (error == 0) {
|
|
uint32_t scopeid;
|
|
|
|
for (cur = *res; cur; cur = cur->ai_next) {
|
|
if (cur->ai_family != AF_INET6) continue;
|
|
sin6 = (struct sockaddr_in6*) (void*) cur->ai_addr;
|
|
if (ip6_str2scopeid(scope, sin6, &scopeid) == -1) {
|
|
free(hostname2);
|
|
return (EAI_NODATA); /* XXX: is return OK? */
|
|
}
|
|
sin6->sin6_scope_id = scopeid;
|
|
}
|
|
}
|
|
|
|
free(hostname2);
|
|
|
|
return error;
|
|
}
|
|
|
|
static int get_canonname(const struct addrinfo* pai, struct addrinfo* ai, const char* str) {
|
|
assert(pai != NULL);
|
|
assert(ai != NULL);
|
|
assert(str != NULL);
|
|
|
|
if ((pai->ai_flags & AI_CANONNAME) != 0) {
|
|
ai->ai_canonname = strdup(str);
|
|
if (ai->ai_canonname == NULL) return EAI_MEMORY;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static struct addrinfo* get_ai(const struct addrinfo* pai, const struct afd* afd,
|
|
const char* addr) {
|
|
char* p;
|
|
struct addrinfo* ai;
|
|
|
|
assert(pai != NULL);
|
|
assert(afd != NULL);
|
|
assert(addr != NULL);
|
|
|
|
ai = (struct addrinfo*) malloc(sizeof(struct addrinfo) + sizeof(sockaddr_union));
|
|
if (ai == NULL) return NULL;
|
|
|
|
memcpy(ai, pai, sizeof(struct addrinfo));
|
|
ai->ai_addr = (struct sockaddr*) (void*) (ai + 1);
|
|
memset(ai->ai_addr, 0, sizeof(sockaddr_union));
|
|
|
|
ai->ai_addrlen = afd->a_socklen;
|
|
ai->ai_addr->sa_family = ai->ai_family = afd->a_af;
|
|
p = (char*) (void*) (ai->ai_addr);
|
|
memcpy(p + afd->a_off, addr, (size_t) afd->a_addrlen);
|
|
return ai;
|
|
}
|
|
|
|
static int get_portmatch(const struct addrinfo* ai, const char* servname) {
|
|
assert(ai != NULL);
|
|
/* servname may be NULL */
|
|
|
|
return get_port(ai, servname, 1);
|
|
}
|
|
|
|
static int get_port(const struct addrinfo* ai, const char* servname, int matchonly) {
|
|
const char* proto;
|
|
struct servent* sp;
|
|
int port;
|
|
int allownumeric;
|
|
|
|
assert(ai != NULL);
|
|
/* servname may be NULL */
|
|
|
|
if (servname == NULL) return 0;
|
|
switch (ai->ai_family) {
|
|
case AF_INET:
|
|
case AF_INET6:
|
|
break;
|
|
default:
|
|
return 0;
|
|
}
|
|
|
|
switch (ai->ai_socktype) {
|
|
case SOCK_RAW:
|
|
return EAI_SERVICE;
|
|
case SOCK_DGRAM:
|
|
case SOCK_STREAM:
|
|
case ANY:
|
|
allownumeric = 1;
|
|
break;
|
|
default:
|
|
return EAI_SOCKTYPE;
|
|
}
|
|
|
|
port = str2number(servname);
|
|
if (port >= 0) {
|
|
if (!allownumeric) return EAI_SERVICE;
|
|
if (port < 0 || port > 65535) return EAI_SERVICE;
|
|
port = htons(port);
|
|
} else {
|
|
if (ai->ai_flags & AI_NUMERICSERV) return EAI_NONAME;
|
|
|
|
switch (ai->ai_socktype) {
|
|
case SOCK_DGRAM:
|
|
proto = "udp";
|
|
break;
|
|
case SOCK_STREAM:
|
|
proto = "tcp";
|
|
break;
|
|
default:
|
|
proto = NULL;
|
|
break;
|
|
}
|
|
|
|
if ((sp = getservbyname(servname, proto)) == NULL) return EAI_SERVICE;
|
|
port = sp->s_port;
|
|
}
|
|
|
|
if (!matchonly) {
|
|
switch (ai->ai_family) {
|
|
case AF_INET:
|
|
((struct sockaddr_in*) (void*) ai->ai_addr)->sin_port = port;
|
|
break;
|
|
case AF_INET6:
|
|
((struct sockaddr_in6*) (void*) ai->ai_addr)->sin6_port = port;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct afd* find_afd(int af) {
|
|
const struct afd* afd;
|
|
|
|
if (af == PF_UNSPEC) return NULL;
|
|
for (afd = afdl; afd->a_af; afd++) {
|
|
if (afd->a_af == af) return afd;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
// Convert a string to a scope identifier.
|
|
static int ip6_str2scopeid(const char* scope, struct sockaddr_in6* sin6, uint32_t* scopeid) {
|
|
uint64_t lscopeid;
|
|
struct in6_addr* a6;
|
|
char* ep;
|
|
|
|
assert(scope != NULL);
|
|
assert(sin6 != NULL);
|
|
assert(scopeid != NULL);
|
|
|
|
a6 = &sin6->sin6_addr;
|
|
|
|
/* empty scopeid portion is invalid */
|
|
if (*scope == '\0') return -1;
|
|
|
|
if (IN6_IS_ADDR_LINKLOCAL(a6) || IN6_IS_ADDR_MC_LINKLOCAL(a6)) {
|
|
/*
|
|
* We currently assume a one-to-one mapping between links
|
|
* and interfaces, so we simply use interface indices for
|
|
* like-local scopes.
|
|
*/
|
|
*scopeid = if_nametoindex(scope);
|
|
if (*scopeid != 0) return 0;
|
|
}
|
|
|
|
// try to convert to a numeric id as a last resort
|
|
errno = 0;
|
|
lscopeid = strtoul(scope, &ep, 10);
|
|
*scopeid = (uint32_t)(lscopeid & 0xffffffffUL);
|
|
if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid)
|
|
return 0;
|
|
else
|
|
return -1;
|
|
}
|
|
|
|
/* code duplicate with gethnamaddr.c */
|
|
|
|
#define BOUNDED_INCR(x) \
|
|
do { \
|
|
BOUNDS_CHECK(cp, x); \
|
|
cp += (x); \
|
|
} while (0)
|
|
|
|
#define BOUNDS_CHECK(ptr, count) \
|
|
do { \
|
|
if (eom - (ptr) < (count)) { \
|
|
*herrno = NO_RECOVERY; \
|
|
return NULL; \
|
|
} \
|
|
} while (0)
|
|
|
|
static struct addrinfo* getanswer(const std::vector<uint8_t>& answer, int anslen, const char* qname,
|
|
int qtype, const struct addrinfo* pai, int* herrno) {
|
|
struct addrinfo sentinel = {};
|
|
struct addrinfo *cur;
|
|
struct addrinfo ai;
|
|
const struct afd* afd;
|
|
char* canonname;
|
|
const HEADER* hp;
|
|
const uint8_t* cp;
|
|
int n;
|
|
const uint8_t* eom;
|
|
char *bp, *ep;
|
|
int type, ancount, qdcount;
|
|
int haveanswer, had_error;
|
|
char tbuf[MAXDNAME];
|
|
char hostbuf[8 * 1024];
|
|
|
|
assert(qname != NULL);
|
|
assert(pai != NULL);
|
|
|
|
cur = &sentinel;
|
|
|
|
canonname = NULL;
|
|
eom = answer.data() + anslen;
|
|
|
|
bool (*name_ok)(const char* dn);
|
|
switch (qtype) {
|
|
case T_A:
|
|
case T_AAAA:
|
|
case T_ANY: /*use T_ANY only for T_A/T_AAAA lookup*/
|
|
name_ok = res_hnok;
|
|
break;
|
|
default:
|
|
return NULL; /* XXX should be abort(); */
|
|
}
|
|
/*
|
|
* find first satisfactory answer
|
|
*/
|
|
hp = reinterpret_cast<const HEADER*>(answer.data());
|
|
ancount = ntohs(hp->ancount);
|
|
qdcount = ntohs(hp->qdcount);
|
|
bp = hostbuf;
|
|
ep = hostbuf + sizeof hostbuf;
|
|
cp = answer.data();
|
|
BOUNDED_INCR(HFIXEDSZ);
|
|
if (qdcount != 1) {
|
|
*herrno = NO_RECOVERY;
|
|
return (NULL);
|
|
}
|
|
n = dn_expand(answer.data(), eom, cp, bp, ep - bp);
|
|
if ((n < 0) || !(*name_ok)(bp)) {
|
|
*herrno = NO_RECOVERY;
|
|
return (NULL);
|
|
}
|
|
BOUNDED_INCR(n + QFIXEDSZ);
|
|
if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
|
|
/* res_send() has already verified that the query name is the
|
|
* same as the one we sent; this just gets the expanded name
|
|
* (i.e., with the succeeding search-domain tacked on).
|
|
*/
|
|
n = strlen(bp) + 1; /* for the \0 */
|
|
if (n >= MAXHOSTNAMELEN) {
|
|
*herrno = NO_RECOVERY;
|
|
return (NULL);
|
|
}
|
|
canonname = bp;
|
|
bp += n;
|
|
/* The qname can be abbreviated, but h_name is now absolute. */
|
|
qname = canonname;
|
|
}
|
|
haveanswer = 0;
|
|
had_error = 0;
|
|
while (ancount-- > 0 && cp < eom && !had_error) {
|
|
n = dn_expand(answer.data(), eom, cp, bp, ep - bp);
|
|
if ((n < 0) || !(*name_ok)(bp)) {
|
|
had_error++;
|
|
continue;
|
|
}
|
|
cp += n; /* name */
|
|
BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
|
|
type = ntohs(*reinterpret_cast<const uint16_t*>(cp));
|
|
cp += INT16SZ; /* type */
|
|
int cl = ntohs(*reinterpret_cast<const uint16_t*>(cp));
|
|
cp += INT16SZ + INT32SZ; /* class, TTL */
|
|
n = ntohs(*reinterpret_cast<const uint16_t*>(cp));
|
|
cp += INT16SZ; /* len */
|
|
BOUNDS_CHECK(cp, n);
|
|
if (cl != C_IN) {
|
|
/* XXX - debug? syslog? */
|
|
cp += n;
|
|
continue; /* XXX - had_error++ ? */
|
|
}
|
|
if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) && type == T_CNAME) {
|
|
n = dn_expand(answer.data(), eom, cp, tbuf, sizeof tbuf);
|
|
if ((n < 0) || !(*name_ok)(tbuf)) {
|
|
had_error++;
|
|
continue;
|
|
}
|
|
cp += n;
|
|
/* Get canonical name. */
|
|
n = strlen(tbuf) + 1; /* for the \0 */
|
|
if (n > ep - bp || n >= MAXHOSTNAMELEN) {
|
|
had_error++;
|
|
continue;
|
|
}
|
|
strlcpy(bp, tbuf, (size_t)(ep - bp));
|
|
canonname = bp;
|
|
bp += n;
|
|
continue;
|
|
}
|
|
if (qtype == T_ANY) {
|
|
if (!(type == T_A || type == T_AAAA)) {
|
|
cp += n;
|
|
continue;
|
|
}
|
|
} else if (type != qtype) {
|
|
if (type != T_KEY && type != T_SIG)
|
|
LOG(DEBUG) << __func__ << ": asked for \"" << qname << " " << p_class(C_IN) << " "
|
|
<< p_type(qtype) << "\", got type \"" << p_type(type) << "\"";
|
|
cp += n;
|
|
continue; /* XXX - had_error++ ? */
|
|
}
|
|
switch (type) {
|
|
case T_A:
|
|
case T_AAAA:
|
|
if (strcasecmp(canonname, bp) != 0) {
|
|
LOG(DEBUG) << __func__ << ": asked for \"" << canonname << "\", got \"" << bp
|
|
<< "\"";
|
|
cp += n;
|
|
continue; /* XXX - had_error++ ? */
|
|
}
|
|
if (type == T_A && n != INADDRSZ) {
|
|
cp += n;
|
|
continue;
|
|
}
|
|
if (type == T_AAAA && n != IN6ADDRSZ) {
|
|
cp += n;
|
|
continue;
|
|
}
|
|
if (type == T_AAAA) {
|
|
struct in6_addr in6;
|
|
memcpy(&in6, cp, IN6ADDRSZ);
|
|
if (IN6_IS_ADDR_V4MAPPED(&in6)) {
|
|
cp += n;
|
|
continue;
|
|
}
|
|
}
|
|
if (!haveanswer) {
|
|
int nn;
|
|
|
|
canonname = bp;
|
|
nn = strlen(bp) + 1; /* for the \0 */
|
|
bp += nn;
|
|
}
|
|
|
|
/* don't overwrite pai */
|
|
ai = *pai;
|
|
ai.ai_family = (type == T_A) ? AF_INET : AF_INET6;
|
|
afd = find_afd(ai.ai_family);
|
|
if (afd == NULL) {
|
|
cp += n;
|
|
continue;
|
|
}
|
|
cur->ai_next = get_ai(&ai, afd, (const char*) cp);
|
|
if (cur->ai_next == NULL) had_error++;
|
|
while (cur && cur->ai_next) cur = cur->ai_next;
|
|
cp += n;
|
|
break;
|
|
default:
|
|
abort();
|
|
}
|
|
if (!had_error) haveanswer++;
|
|
}
|
|
if (haveanswer) {
|
|
if (!canonname)
|
|
(void) get_canonname(pai, sentinel.ai_next, qname);
|
|
else
|
|
(void) get_canonname(pai, sentinel.ai_next, canonname);
|
|
*herrno = NETDB_SUCCESS;
|
|
return sentinel.ai_next;
|
|
}
|
|
|
|
*herrno = NO_RECOVERY;
|
|
return NULL;
|
|
}
|
|
|
|
struct addrinfo_sort_elem {
|
|
struct addrinfo* ai;
|
|
int has_src_addr;
|
|
sockaddr_union src_addr;
|
|
int original_order;
|
|
};
|
|
|
|
static int _get_scope(const struct sockaddr* addr) {
|
|
if (addr->sa_family == AF_INET6) {
|
|
const struct sockaddr_in6* addr6 = (const struct sockaddr_in6*) addr;
|
|
if (IN6_IS_ADDR_MULTICAST(&addr6->sin6_addr)) {
|
|
return IPV6_ADDR_MC_SCOPE(&addr6->sin6_addr);
|
|
} else if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr) ||
|
|
IN6_IS_ADDR_LINKLOCAL(&addr6->sin6_addr)) {
|
|
/*
|
|
* RFC 4291 section 2.5.3 says loopback is to be treated as having
|
|
* link-local scope.
|
|
*/
|
|
return IPV6_ADDR_SCOPE_LINKLOCAL;
|
|
} else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
|
|
return IPV6_ADDR_SCOPE_SITELOCAL;
|
|
} else {
|
|
return IPV6_ADDR_SCOPE_GLOBAL;
|
|
}
|
|
} else if (addr->sa_family == AF_INET) {
|
|
const struct sockaddr_in* addr4 = (const struct sockaddr_in*) addr;
|
|
unsigned long int na = ntohl(addr4->sin_addr.s_addr);
|
|
|
|
if (IN_LOOPBACK(na) || /* 127.0.0.0/8 */
|
|
(na & 0xffff0000) == 0xa9fe0000) { /* 169.254.0.0/16 */
|
|
return IPV6_ADDR_SCOPE_LINKLOCAL;
|
|
} else {
|
|
/*
|
|
* RFC 6724 section 3.2. Other IPv4 addresses, including private addresses
|
|
* and shared addresses (100.64.0.0/10), are assigned global scope.
|
|
*/
|
|
return IPV6_ADDR_SCOPE_GLOBAL;
|
|
}
|
|
} else {
|
|
/*
|
|
* This should never happen.
|
|
* Return a scope with low priority as a last resort.
|
|
*/
|
|
return IPV6_ADDR_SCOPE_NODELOCAL;
|
|
}
|
|
}
|
|
|
|
/* These macros are modelled after the ones in <netinet/in6.h>. */
|
|
|
|
/* RFC 4380, section 2.6 */
|
|
#define IN6_IS_ADDR_TEREDO(a) \
|
|
((*(const uint32_t*) (const void*) (&(a)->s6_addr[0]) == ntohl(0x20010000)))
|
|
|
|
/* RFC 3056, section 2. */
|
|
#define IN6_IS_ADDR_6TO4(a) (((a)->s6_addr[0] == 0x20) && ((a)->s6_addr[1] == 0x02))
|
|
|
|
/* 6bone testing address area (3ffe::/16), deprecated in RFC 3701. */
|
|
#define IN6_IS_ADDR_6BONE(a) (((a)->s6_addr[0] == 0x3f) && ((a)->s6_addr[1] == 0xfe))
|
|
|
|
/*
|
|
* Get the label for a given IPv4/IPv6 address.
|
|
* RFC 6724, section 2.1.
|
|
*/
|
|
|
|
static int _get_label(const struct sockaddr* addr) {
|
|
if (addr->sa_family == AF_INET) {
|
|
return 4;
|
|
} else if (addr->sa_family == AF_INET6) {
|
|
const struct sockaddr_in6* addr6 = (const struct sockaddr_in6*) addr;
|
|
if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
|
|
return 0;
|
|
} else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
|
|
return 4;
|
|
} else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
|
|
return 2;
|
|
} else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
|
|
return 5;
|
|
} else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
|
|
return 13;
|
|
} else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) {
|
|
return 3;
|
|
} else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) {
|
|
return 11;
|
|
} else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
|
|
return 12;
|
|
} else {
|
|
/* All other IPv6 addresses, including global unicast addresses. */
|
|
return 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* This should never happen.
|
|
* Return a semi-random label as a last resort.
|
|
*/
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the precedence for a given IPv4/IPv6 address.
|
|
* RFC 6724, section 2.1.
|
|
*/
|
|
|
|
static int _get_precedence(const struct sockaddr* addr) {
|
|
if (addr->sa_family == AF_INET) {
|
|
return 35;
|
|
} else if (addr->sa_family == AF_INET6) {
|
|
const struct sockaddr_in6* addr6 = (const struct sockaddr_in6*) addr;
|
|
if (IN6_IS_ADDR_LOOPBACK(&addr6->sin6_addr)) {
|
|
return 50;
|
|
} else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) {
|
|
return 35;
|
|
} else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) {
|
|
return 30;
|
|
} else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) {
|
|
return 5;
|
|
} else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) {
|
|
return 3;
|
|
} else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr) ||
|
|
IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr) ||
|
|
IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) {
|
|
return 1;
|
|
} else {
|
|
/* All other IPv6 addresses, including global unicast addresses. */
|
|
return 40;
|
|
}
|
|
} else {
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Find number of matching initial bits between the two addresses a1 and a2.
|
|
*/
|
|
|
|
static int _common_prefix_len(const struct in6_addr* a1, const struct in6_addr* a2) {
|
|
const char* p1 = (const char*) a1;
|
|
const char* p2 = (const char*) a2;
|
|
unsigned i;
|
|
|
|
for (i = 0; i < sizeof(*a1); ++i) {
|
|
int x, j;
|
|
|
|
if (p1[i] == p2[i]) {
|
|
continue;
|
|
}
|
|
x = p1[i] ^ p2[i];
|
|
for (j = 0; j < CHAR_BIT; ++j) {
|
|
if (x & (1 << (CHAR_BIT - 1))) {
|
|
return i * CHAR_BIT + j;
|
|
}
|
|
x <<= 1;
|
|
}
|
|
}
|
|
return sizeof(*a1) * CHAR_BIT;
|
|
}
|
|
|
|
/*
|
|
* Compare two source/destination address pairs.
|
|
* RFC 6724, section 6.
|
|
*/
|
|
|
|
static int _rfc6724_compare(const void* ptr1, const void* ptr2) {
|
|
const struct addrinfo_sort_elem* a1 = (const struct addrinfo_sort_elem*) ptr1;
|
|
const struct addrinfo_sort_elem* a2 = (const struct addrinfo_sort_elem*) ptr2;
|
|
int scope_src1, scope_dst1, scope_match1;
|
|
int scope_src2, scope_dst2, scope_match2;
|
|
int label_src1, label_dst1, label_match1;
|
|
int label_src2, label_dst2, label_match2;
|
|
int precedence1, precedence2;
|
|
int prefixlen1, prefixlen2;
|
|
|
|
/* Rule 1: Avoid unusable destinations. */
|
|
if (a1->has_src_addr != a2->has_src_addr) {
|
|
return a2->has_src_addr - a1->has_src_addr;
|
|
}
|
|
|
|
/* Rule 2: Prefer matching scope. */
|
|
scope_src1 = _get_scope(&a1->src_addr.sa);
|
|
scope_dst1 = _get_scope(a1->ai->ai_addr);
|
|
scope_match1 = (scope_src1 == scope_dst1);
|
|
|
|
scope_src2 = _get_scope(&a2->src_addr.sa);
|
|
scope_dst2 = _get_scope(a2->ai->ai_addr);
|
|
scope_match2 = (scope_src2 == scope_dst2);
|
|
|
|
if (scope_match1 != scope_match2) {
|
|
return scope_match2 - scope_match1;
|
|
}
|
|
|
|
/*
|
|
* Rule 3: Avoid deprecated addresses.
|
|
* TODO(sesse): We don't currently have a good way of finding this.
|
|
*/
|
|
|
|
/*
|
|
* Rule 4: Prefer home addresses.
|
|
* TODO(sesse): We don't currently have a good way of finding this.
|
|
*/
|
|
|
|
/* Rule 5: Prefer matching label. */
|
|
label_src1 = _get_label(&a1->src_addr.sa);
|
|
label_dst1 = _get_label(a1->ai->ai_addr);
|
|
label_match1 = (label_src1 == label_dst1);
|
|
|
|
label_src2 = _get_label(&a2->src_addr.sa);
|
|
label_dst2 = _get_label(a2->ai->ai_addr);
|
|
label_match2 = (label_src2 == label_dst2);
|
|
|
|
if (label_match1 != label_match2) {
|
|
return label_match2 - label_match1;
|
|
}
|
|
|
|
/* Rule 6: Prefer higher precedence. */
|
|
precedence1 = _get_precedence(a1->ai->ai_addr);
|
|
precedence2 = _get_precedence(a2->ai->ai_addr);
|
|
if (precedence1 != precedence2) {
|
|
return precedence2 - precedence1;
|
|
}
|
|
|
|
/*
|
|
* Rule 7: Prefer native transport.
|
|
* TODO(sesse): We don't currently have a good way of finding this.
|
|
*/
|
|
|
|
/* Rule 8: Prefer smaller scope. */
|
|
if (scope_dst1 != scope_dst2) {
|
|
return scope_dst1 - scope_dst2;
|
|
}
|
|
|
|
/*
|
|
* Rule 9: Use longest matching prefix.
|
|
* We implement this for IPv6 only, as the rules in RFC 6724 don't seem
|
|
* to work very well directly applied to IPv4. (glibc uses information from
|
|
* the routing table for a custom IPv4 implementation here.)
|
|
*/
|
|
if (a1->has_src_addr && a1->ai->ai_addr->sa_family == AF_INET6 && a2->has_src_addr &&
|
|
a2->ai->ai_addr->sa_family == AF_INET6) {
|
|
const struct sockaddr_in6* a1_src = &a1->src_addr.sin6;
|
|
const struct sockaddr_in6* a1_dst = (const struct sockaddr_in6*) a1->ai->ai_addr;
|
|
const struct sockaddr_in6* a2_src = &a2->src_addr.sin6;
|
|
const struct sockaddr_in6* a2_dst = (const struct sockaddr_in6*) a2->ai->ai_addr;
|
|
prefixlen1 = _common_prefix_len(&a1_src->sin6_addr, &a1_dst->sin6_addr);
|
|
prefixlen2 = _common_prefix_len(&a2_src->sin6_addr, &a2_dst->sin6_addr);
|
|
if (prefixlen1 != prefixlen2) {
|
|
return prefixlen2 - prefixlen1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Rule 10: Leave the order unchanged.
|
|
* We need this since qsort() is not necessarily stable.
|
|
*/
|
|
return a1->original_order - a2->original_order;
|
|
}
|
|
|
|
/*
|
|
* Find the source address that will be used if trying to connect to the given
|
|
* address. src_addr must be large enough to hold a struct sockaddr_in6.
|
|
*
|
|
* Returns 1 if a source address was found, 0 if the address is unreachable,
|
|
* and -1 if a fatal error occurred. If 0 or -1, the contents of src_addr are
|
|
* undefined.
|
|
*/
|
|
|
|
static int _find_src_addr(const struct sockaddr* addr, struct sockaddr* src_addr, unsigned mark,
|
|
uid_t uid) {
|
|
int sock;
|
|
int ret;
|
|
socklen_t len;
|
|
|
|
switch (addr->sa_family) {
|
|
case AF_INET:
|
|
len = sizeof(struct sockaddr_in);
|
|
break;
|
|
case AF_INET6:
|
|
len = sizeof(struct sockaddr_in6);
|
|
break;
|
|
default:
|
|
/* No known usable source address for non-INET families. */
|
|
return 0;
|
|
}
|
|
|
|
sock = socket(addr->sa_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
|
|
if (sock == -1) {
|
|
if (errno == EAFNOSUPPORT) {
|
|
return 0;
|
|
} else {
|
|
return -1;
|
|
}
|
|
}
|
|
if (mark != MARK_UNSET && setsockopt(sock, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0) {
|
|
close(sock);
|
|
return 0;
|
|
}
|
|
if (uid > 0 && uid != NET_CONTEXT_INVALID_UID && fchown(sock, uid, (gid_t) -1) < 0) {
|
|
close(sock);
|
|
return 0;
|
|
}
|
|
do {
|
|
ret = connect(sock, addr, len);
|
|
} while (ret == -1 && errno == EINTR);
|
|
|
|
if (ret == -1) {
|
|
close(sock);
|
|
return 0;
|
|
}
|
|
|
|
if (src_addr && getsockname(sock, src_addr, &len) == -1) {
|
|
close(sock);
|
|
return -1;
|
|
}
|
|
close(sock);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Sort the linked list starting at sentinel->ai_next in RFC6724 order.
|
|
* Will leave the list unchanged if an error occurs.
|
|
*/
|
|
|
|
static void _rfc6724_sort(struct addrinfo* list_sentinel, unsigned mark, uid_t uid) {
|
|
struct addrinfo* cur;
|
|
int nelem = 0, i;
|
|
struct addrinfo_sort_elem* elems;
|
|
|
|
cur = list_sentinel->ai_next;
|
|
while (cur) {
|
|
++nelem;
|
|
cur = cur->ai_next;
|
|
}
|
|
|
|
elems = (struct addrinfo_sort_elem*) malloc(nelem * sizeof(struct addrinfo_sort_elem));
|
|
if (elems == NULL) {
|
|
goto error;
|
|
}
|
|
|
|
/*
|
|
* Convert the linked list to an array that also contains the candidate
|
|
* source address for each destination address.
|
|
*/
|
|
for (i = 0, cur = list_sentinel->ai_next; i < nelem; ++i, cur = cur->ai_next) {
|
|
int has_src_addr;
|
|
assert(cur != NULL);
|
|
elems[i].ai = cur;
|
|
elems[i].original_order = i;
|
|
|
|
has_src_addr = _find_src_addr(cur->ai_addr, &elems[i].src_addr.sa, mark, uid);
|
|
if (has_src_addr == -1) {
|
|
goto error;
|
|
}
|
|
elems[i].has_src_addr = has_src_addr;
|
|
}
|
|
|
|
/* Sort the addresses, and rearrange the linked list so it matches the sorted order. */
|
|
qsort((void*) elems, nelem, sizeof(struct addrinfo_sort_elem), _rfc6724_compare);
|
|
|
|
list_sentinel->ai_next = elems[0].ai;
|
|
for (i = 0; i < nelem - 1; ++i) {
|
|
elems[i].ai->ai_next = elems[i + 1].ai;
|
|
}
|
|
elems[nelem - 1].ai->ai_next = NULL;
|
|
|
|
error:
|
|
free(elems);
|
|
}
|
|
|
|
static int dns_getaddrinfo(const char* name, const addrinfo* pai,
|
|
const android_net_context* netcontext, addrinfo** rv,
|
|
NetworkDnsEventReported* event) {
|
|
res_target q = {};
|
|
res_target q2 = {};
|
|
|
|
switch (pai->ai_family) {
|
|
case AF_UNSPEC: {
|
|
/* prefer IPv6 */
|
|
q.name = name;
|
|
q.qclass = C_IN;
|
|
int query_ipv6 = 1, query_ipv4 = 1;
|
|
if (pai->ai_flags & AI_ADDRCONFIG) {
|
|
query_ipv6 = have_ipv6(netcontext->app_mark, netcontext->uid);
|
|
query_ipv4 = have_ipv4(netcontext->app_mark, netcontext->uid);
|
|
}
|
|
if (query_ipv6) {
|
|
q.qtype = T_AAAA;
|
|
if (query_ipv4) {
|
|
q.next = &q2;
|
|
q2.name = name;
|
|
q2.qclass = C_IN;
|
|
q2.qtype = T_A;
|
|
}
|
|
} else if (query_ipv4) {
|
|
q.qtype = T_A;
|
|
} else {
|
|
return EAI_NODATA;
|
|
}
|
|
break;
|
|
}
|
|
case AF_INET:
|
|
q.name = name;
|
|
q.qclass = C_IN;
|
|
q.qtype = T_A;
|
|
break;
|
|
case AF_INET6:
|
|
q.name = name;
|
|
q.qclass = C_IN;
|
|
q.qtype = T_AAAA;
|
|
break;
|
|
default:
|
|
return EAI_FAMILY;
|
|
}
|
|
|
|
ResState res(netcontext, event);
|
|
|
|
setMdnsFlag(name, res.netid, &(res.flags));
|
|
|
|
int he;
|
|
if (res_searchN(name, &q, &res, &he) < 0) {
|
|
// Return h_errno (he) to catch more detailed errors rather than EAI_NODATA.
|
|
// Note that res_searchN() doesn't set the pair NETDB_INTERNAL and errno.
|
|
// See also herrnoToAiErrno().
|
|
return herrnoToAiErrno(he);
|
|
}
|
|
|
|
addrinfo sentinel = {};
|
|
addrinfo* cur = &sentinel;
|
|
addrinfo* ai = getanswer(q.answer, q.n, q.name, q.qtype, pai, &he);
|
|
if (ai) {
|
|
cur->ai_next = ai;
|
|
while (cur && cur->ai_next) cur = cur->ai_next;
|
|
}
|
|
if (q.next) {
|
|
ai = getanswer(q2.answer, q2.n, q2.name, q2.qtype, pai, &he);
|
|
if (ai) cur->ai_next = ai;
|
|
}
|
|
if (sentinel.ai_next == NULL) {
|
|
// Note that getanswer() doesn't set the pair NETDB_INTERNAL and errno.
|
|
// See also herrnoToAiErrno().
|
|
return herrnoToAiErrno(he);
|
|
}
|
|
|
|
_rfc6724_sort(&sentinel, netcontext->app_mark, netcontext->uid);
|
|
|
|
*rv = sentinel.ai_next;
|
|
return 0;
|
|
}
|
|
|
|
static void _sethtent(FILE** hostf) {
|
|
if (!*hostf)
|
|
*hostf = fopen(_PATH_HOSTS, "re");
|
|
else
|
|
rewind(*hostf);
|
|
}
|
|
|
|
static void _endhtent(FILE** hostf) {
|
|
if (*hostf) {
|
|
(void) fclose(*hostf);
|
|
*hostf = NULL;
|
|
}
|
|
}
|
|
|
|
static struct addrinfo* _gethtent(FILE** hostf, const char* name, const struct addrinfo* pai) {
|
|
char* p;
|
|
char *cp, *tname, *cname;
|
|
struct addrinfo *res0, *res;
|
|
int error;
|
|
const char* addr;
|
|
char hostbuf[8 * 1024];
|
|
|
|
assert(name != NULL);
|
|
assert(pai != NULL);
|
|
|
|
if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "re"))) return (NULL);
|
|
again:
|
|
if (!(p = fgets(hostbuf, sizeof hostbuf, *hostf))) return (NULL);
|
|
if (*p == '#') goto again;
|
|
if (!(cp = strpbrk(p, "#\n"))) goto again;
|
|
*cp = '\0';
|
|
if (!(cp = strpbrk(p, " \t"))) goto again;
|
|
*cp++ = '\0';
|
|
addr = p;
|
|
/* if this is not something we're looking for, skip it. */
|
|
cname = NULL;
|
|
while (cp && *cp) {
|
|
if (*cp == ' ' || *cp == '\t') {
|
|
cp++;
|
|
continue;
|
|
}
|
|
if (!cname) cname = cp;
|
|
tname = cp;
|
|
if ((cp = strpbrk(cp, " \t")) != NULL) *cp++ = '\0';
|
|
if (strcasecmp(name, tname) == 0) goto found;
|
|
}
|
|
goto again;
|
|
|
|
found:
|
|
error = getaddrinfo_numeric(addr, nullptr, *pai, &res0);
|
|
if (error) goto again;
|
|
for (res = res0; res; res = res->ai_next) {
|
|
/* cover it up */
|
|
res->ai_flags = pai->ai_flags;
|
|
|
|
if (pai->ai_flags & AI_CANONNAME) {
|
|
if (get_canonname(pai, res, cname) != 0) {
|
|
freeaddrinfo(res0);
|
|
goto again;
|
|
}
|
|
}
|
|
}
|
|
return res0;
|
|
}
|
|
|
|
static struct addrinfo* getCustomHosts(const size_t netid, const char* _Nonnull name,
|
|
const struct addrinfo* _Nonnull pai) {
|
|
struct addrinfo sentinel = {};
|
|
struct addrinfo *res0, *res;
|
|
res = &sentinel;
|
|
std::vector<std::string> hosts = getCustomizedTableByName(netid, name);
|
|
for (const std::string& host : hosts) {
|
|
int error = getaddrinfo_numeric(host.c_str(), nullptr, *pai, &res0);
|
|
if (!error && res0 != nullptr) {
|
|
res->ai_next = res0;
|
|
res = res0;
|
|
res0 = nullptr;
|
|
}
|
|
}
|
|
return sentinel.ai_next;
|
|
}
|
|
|
|
static bool files_getaddrinfo(const size_t netid, const char* name, const addrinfo* pai,
|
|
addrinfo** res) {
|
|
struct addrinfo sentinel = {};
|
|
struct addrinfo *p, *cur;
|
|
FILE* hostf = nullptr;
|
|
|
|
cur = &sentinel;
|
|
_sethtent(&hostf);
|
|
while ((p = _gethtent(&hostf, name, pai)) != nullptr) {
|
|
cur->ai_next = p;
|
|
while (cur && cur->ai_next) cur = cur->ai_next;
|
|
}
|
|
_endhtent(&hostf);
|
|
|
|
if ((p = getCustomHosts(netid, name, pai)) != nullptr) {
|
|
cur->ai_next = p;
|
|
}
|
|
|
|
*res = sentinel.ai_next;
|
|
return sentinel.ai_next != nullptr;
|
|
}
|
|
|
|
/* resolver logic */
|
|
|
|
namespace {
|
|
|
|
constexpr int SLEEP_TIME_MS = 2;
|
|
|
|
int getHerrnoFromRcode(int rcode) {
|
|
switch (rcode) {
|
|
// Not defined in RFC.
|
|
case RCODE_TIMEOUT:
|
|
// DNS metrics monitors DNS query timeout.
|
|
return NETD_RESOLV_H_ERRNO_EXT_TIMEOUT; // extended h_errno.
|
|
// Defined in RFC 1035 section 4.1.1.
|
|
case NXDOMAIN:
|
|
return HOST_NOT_FOUND;
|
|
case SERVFAIL:
|
|
return TRY_AGAIN;
|
|
case NOERROR:
|
|
return NO_DATA;
|
|
case FORMERR:
|
|
case NOTIMP:
|
|
case REFUSED:
|
|
default:
|
|
return NO_RECOVERY;
|
|
}
|
|
}
|
|
|
|
struct QueryResult {
|
|
int ancount;
|
|
int rcode;
|
|
int herrno;
|
|
int qerrno;
|
|
NetworkDnsEventReported event;
|
|
};
|
|
|
|
QueryResult doQuery(const char* name, res_target* t, ResState* res,
|
|
std::chrono::milliseconds sleepTimeMs) {
|
|
HEADER* hp = (HEADER*)(void*)t->answer.data();
|
|
|
|
hp->rcode = NOERROR; // default
|
|
|
|
const int cl = t->qclass;
|
|
const int type = t->qtype;
|
|
const int anslen = t->answer.size();
|
|
|
|
LOG(DEBUG) << __func__ << ": (" << cl << ", " << type << ")";
|
|
|
|
uint8_t buf[MAXPACKET];
|
|
int n = res_nmkquery(QUERY, name, cl, type, {}, buf, res->netcontext_flags);
|
|
|
|
if (n > 0 &&
|
|
(res->netcontext_flags & (NET_CONTEXT_FLAG_USE_DNS_OVER_TLS | NET_CONTEXT_FLAG_USE_EDNS))) {
|
|
n = res_nopt(res, n, buf, anslen);
|
|
}
|
|
|
|
NetworkDnsEventReported event;
|
|
if (n <= 0) {
|
|
LOG(ERROR) << __func__ << ": res_nmkquery failed";
|
|
return {
|
|
.ancount = 0,
|
|
.rcode = -1,
|
|
.herrno = NO_RECOVERY,
|
|
.qerrno = errno,
|
|
.event = event,
|
|
};
|
|
}
|
|
|
|
ResState res_temp = res->clone(&event);
|
|
|
|
int rcode = NOERROR;
|
|
n = res_nsend(&res_temp, {buf, n}, {t->answer.data(), anslen}, &rcode, 0, sleepTimeMs);
|
|
if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
|
|
// To ensure that the rcode handling is identical to res_queryN().
|
|
if (rcode != RCODE_TIMEOUT) rcode = hp->rcode;
|
|
// if the query choked with EDNS0, retry without EDNS0
|
|
if ((res_temp.netcontext_flags &
|
|
(NET_CONTEXT_FLAG_USE_DNS_OVER_TLS | NET_CONTEXT_FLAG_USE_EDNS)) &&
|
|
(res_temp.flags & RES_F_EDNS0ERR)) {
|
|
LOG(DEBUG) << __func__ << ": retry without EDNS0";
|
|
n = res_nmkquery(QUERY, name, cl, type, {}, buf, res_temp.netcontext_flags);
|
|
n = res_nsend(&res_temp, {buf, n}, {t->answer.data(), anslen}, &rcode, 0);
|
|
}
|
|
}
|
|
|
|
LOG(DEBUG) << __func__ << ": rcode=" << hp->rcode << ", ancount=" << ntohs(hp->ancount);
|
|
|
|
t->n = n;
|
|
return {
|
|
.ancount = ntohs(hp->ancount),
|
|
.rcode = rcode,
|
|
.qerrno = errno,
|
|
.event = event,
|
|
};
|
|
}
|
|
|
|
} // namespace
|
|
|
|
static int res_queryN_parallel(const char* name, res_target* target, ResState* res, int* herrno) {
|
|
std::vector<std::future<QueryResult>> results;
|
|
results.reserve(2);
|
|
std::chrono::milliseconds sleepTimeMs{};
|
|
for (res_target* t = target; t; t = t->next) {
|
|
results.emplace_back(std::async(std::launch::async, doQuery, name, t, res, sleepTimeMs));
|
|
// Avoiding gateways drop packets if queries are sent too close together
|
|
// Only needed if we have multiple queries in a row.
|
|
if (t->next) {
|
|
int sleepFlag = android::net::Experiments::getInstance()->getFlag(
|
|
"parallel_lookup_sleep_time", SLEEP_TIME_MS);
|
|
if (sleepFlag > 1000) sleepFlag = 1000;
|
|
sleepTimeMs = std::chrono::milliseconds(sleepFlag);
|
|
}
|
|
}
|
|
|
|
int ancount = 0;
|
|
int rcode = 0;
|
|
|
|
for (auto& f : results) {
|
|
const QueryResult& r = f.get();
|
|
if (r.herrno == NO_RECOVERY) {
|
|
*herrno = r.herrno;
|
|
return -1;
|
|
}
|
|
res->event->MergeFrom(r.event);
|
|
ancount += r.ancount;
|
|
rcode = r.rcode;
|
|
errno = r.qerrno;
|
|
}
|
|
|
|
if (ancount == 0) {
|
|
*herrno = getHerrnoFromRcode(rcode);
|
|
return -1;
|
|
}
|
|
|
|
return ancount;
|
|
}
|
|
|
|
static int res_queryN_wrapper(const char* name, res_target* target, ResState* res, int* herrno) {
|
|
const bool parallel_lookup =
|
|
android::net::Experiments::getInstance()->getFlag("parallel_lookup_release", 1);
|
|
if (parallel_lookup) return res_queryN_parallel(name, target, res, herrno);
|
|
|
|
return res_queryN(name, target, res, herrno);
|
|
}
|
|
|
|
/*
|
|
* Formulate a normal query, send, and await answer.
|
|
* Returned answer is placed in supplied buffer "answer".
|
|
* Perform preliminary check of answer, returning success only
|
|
* if no error is indicated and the answer count is nonzero.
|
|
* Return the size of the response on success, -1 on error.
|
|
* Error number is left in *herrno.
|
|
*
|
|
* Caller must parse answer and determine whether it answers the question.
|
|
*/
|
|
static int res_queryN(const char* name, res_target* target, ResState* res, int* herrno) {
|
|
uint8_t buf[MAXPACKET];
|
|
int n;
|
|
struct res_target* t;
|
|
int rcode;
|
|
int ancount;
|
|
|
|
assert(name != NULL);
|
|
/* XXX: target may be NULL??? */
|
|
|
|
rcode = NOERROR;
|
|
ancount = 0;
|
|
|
|
for (t = target; t; t = t->next) {
|
|
HEADER* hp = (HEADER*)(void*)t->answer.data();
|
|
bool retried = false;
|
|
again:
|
|
hp->rcode = NOERROR; /* default */
|
|
|
|
/* make it easier... */
|
|
int cl = t->qclass;
|
|
int type = t->qtype;
|
|
const int anslen = t->answer.size();
|
|
|
|
LOG(DEBUG) << __func__ << ": (" << cl << ", " << type << ")";
|
|
n = res_nmkquery(QUERY, name, cl, type, {}, buf, res->netcontext_flags);
|
|
if (n > 0 &&
|
|
(res->netcontext_flags &
|
|
(NET_CONTEXT_FLAG_USE_DNS_OVER_TLS | NET_CONTEXT_FLAG_USE_EDNS)) &&
|
|
!retried) // TODO: remove the retry flag and provide a sufficient test coverage.
|
|
n = res_nopt(res, n, buf, anslen);
|
|
if (n <= 0) {
|
|
LOG(ERROR) << __func__ << ": res_nmkquery failed";
|
|
*herrno = NO_RECOVERY;
|
|
return n;
|
|
}
|
|
|
|
n = res_nsend(res, {buf, n}, {t->answer.data(), anslen}, &rcode, 0);
|
|
if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) {
|
|
// Record rcode from DNS response header only if no timeout.
|
|
// Keep rcode timeout for reporting later if any.
|
|
if (rcode != RCODE_TIMEOUT) rcode = hp->rcode; // record most recent error
|
|
// if the query choked with EDNS0, retry without EDNS0 that when the server
|
|
// has no response, resovler won't retry and do nothing. Even fallback to UDP,
|
|
// we also has the same symptom if EDNS is enabled.
|
|
if ((res->netcontext_flags &
|
|
(NET_CONTEXT_FLAG_USE_DNS_OVER_TLS | NET_CONTEXT_FLAG_USE_EDNS)) &&
|
|
(res->flags & RES_F_EDNS0ERR) && !retried) {
|
|
LOG(DEBUG) << __func__ << ": retry without EDNS0";
|
|
retried = true;
|
|
goto again;
|
|
}
|
|
LOG(DEBUG) << __func__ << ": rcode=" << hp->rcode << ", ancount=" << ntohs(hp->ancount);
|
|
continue;
|
|
}
|
|
|
|
ancount += ntohs(hp->ancount);
|
|
|
|
t->n = n;
|
|
}
|
|
|
|
if (ancount == 0) {
|
|
*herrno = getHerrnoFromRcode(rcode);
|
|
return -1;
|
|
}
|
|
return ancount;
|
|
}
|
|
|
|
/*
|
|
* Formulate a normal query, send, and retrieve answer in supplied buffer.
|
|
* Return the size of the response on success, -1 on error.
|
|
* If enabled, implement search rules until answer or unrecoverable failure
|
|
* is detected. Error code, if any, is left in *herrno.
|
|
*/
|
|
static int res_searchN(const char* name, res_target* target, ResState* res, int* herrno) {
|
|
const char* cp;
|
|
HEADER* hp;
|
|
uint32_t dots;
|
|
int ret, saved_herrno;
|
|
int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
|
|
|
|
assert(name != NULL);
|
|
assert(target != NULL);
|
|
|
|
hp = (HEADER*)(void*)target->answer.data();
|
|
|
|
errno = 0;
|
|
*herrno = HOST_NOT_FOUND; /* default, if we never query */
|
|
dots = 0;
|
|
for (cp = name; *cp; cp++) dots += (*cp == '.');
|
|
const bool trailing_dot = (cp > name && *--cp == '.') ? true : false;
|
|
|
|
/*
|
|
* If there are dots in the name already, let's just give it a try
|
|
* 'as is'. The threshold can be set with the "ndots" option.
|
|
*/
|
|
saved_herrno = -1;
|
|
if (dots >= res->ndots) {
|
|
ret = res_querydomainN(name, NULL, target, res, herrno);
|
|
if (ret > 0) return (ret);
|
|
saved_herrno = *herrno;
|
|
tried_as_is++;
|
|
}
|
|
|
|
/*
|
|
* We do at least one level of search if
|
|
* - there is no dot, or
|
|
* - there is at least one dot and there is no trailing dot.
|
|
* - this is not a .local mDNS lookup.
|
|
*/
|
|
if ((!dots || (dots && !trailing_dot)) && !isMdnsResolution(res->flags)) {
|
|
int done = 0;
|
|
|
|
/* Unfortunately we need to set stuff up before
|
|
* the domain stuff is tried. Will have a better
|
|
* fix after thread pools are used.
|
|
*/
|
|
resolv_populate_res_for_net(res);
|
|
|
|
for (const auto& domain : res->search_domains) {
|
|
ret = res_querydomainN(name, domain.c_str(), target, res, herrno);
|
|
if (ret > 0) return ret;
|
|
|
|
/*
|
|
* If no server present, give up.
|
|
* If name isn't found in this domain,
|
|
* keep trying higher domains in the search list
|
|
* (if that's enabled).
|
|
* On a NO_DATA error, keep trying, otherwise
|
|
* a wildcard entry of another type could keep us
|
|
* from finding this entry higher in the domain.
|
|
* If we get some other error (negative answer or
|
|
* server failure), then stop searching up,
|
|
* but try the input name below in case it's
|
|
* fully-qualified.
|
|
*/
|
|
if (errno == ECONNREFUSED) {
|
|
*herrno = TRY_AGAIN;
|
|
return -1;
|
|
}
|
|
|
|
switch (*herrno) {
|
|
case NO_DATA:
|
|
got_nodata++;
|
|
[[fallthrough]];
|
|
case HOST_NOT_FOUND:
|
|
/* keep trying */
|
|
break;
|
|
case TRY_AGAIN:
|
|
if (hp->rcode == SERVFAIL) {
|
|
/* try next search element, if any */
|
|
got_servfail++;
|
|
break;
|
|
}
|
|
[[fallthrough]];
|
|
default:
|
|
/* anything else implies that we're done */
|
|
done++;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* if we have not already tried the name "as is", do that now.
|
|
* note that we do this regardless of how many dots were in the
|
|
* name or whether it ends with a dot.
|
|
*/
|
|
if (!tried_as_is) {
|
|
ret = res_querydomainN(name, NULL, target, res, herrno);
|
|
if (ret > 0) return ret;
|
|
}
|
|
|
|
/*
|
|
* if we got here, we didn't satisfy the search.
|
|
* if we did an initial full query, return that query's h_errno
|
|
* (note that we wouldn't be here if that query had succeeded).
|
|
* else if we ever got a nodata, send that back as the reason.
|
|
* else send back meaningless h_errno, that being the one from
|
|
* the last DNSRCH we did.
|
|
*/
|
|
if (saved_herrno != -1)
|
|
*herrno = saved_herrno;
|
|
else if (got_nodata)
|
|
*herrno = NO_DATA;
|
|
else if (got_servfail)
|
|
*herrno = TRY_AGAIN;
|
|
return -1;
|
|
}
|
|
|
|
// Perform a call on res_query on the concatenation of name and domain,
|
|
// removing a trailing dot from name if domain is NULL.
|
|
static int res_querydomainN(const char* name, const char* domain, res_target* target, ResState* res,
|
|
int* herrno) {
|
|
char nbuf[MAXDNAME];
|
|
const char* longname = nbuf;
|
|
size_t n, d;
|
|
|
|
assert(name != NULL);
|
|
|
|
if (domain == NULL) {
|
|
// Check for trailing '.'; copy without '.' if present.
|
|
n = strlen(name);
|
|
if (n + 1 > sizeof(nbuf)) {
|
|
*herrno = NO_RECOVERY;
|
|
return -1;
|
|
}
|
|
if (n > 0 && name[--n] == '.') {
|
|
strncpy(nbuf, name, n);
|
|
nbuf[n] = '\0';
|
|
} else
|
|
longname = name;
|
|
} else {
|
|
n = strlen(name);
|
|
d = strlen(domain);
|
|
if (n + 1 + d + 1 > sizeof(nbuf)) {
|
|
*herrno = NO_RECOVERY;
|
|
return -1;
|
|
}
|
|
snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain);
|
|
}
|
|
return res_queryN_wrapper(longname, target, res, herrno);
|
|
}
|