/* $NetBSD: getaddrinfo.c,v 1.82 2006/03/25 12:09:40 rpaulo Exp $ */ /* $KAME: getaddrinfo.c,v 1.29 2000/08/31 17:26:57 itojun Exp $ */ /* * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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. */ /* * Issues to be discussed: * - Thread safe-ness must be checked. * - Return values. There are nonstandard return values defined and used * in the source code. This is because RFC2553 is silent about which error * code must be returned for which situation. * - IPv4 classful (shortened) form. RFC2553 is silent about it. XNET 5.2 * says to use inet_aton() to convert IPv4 numeric to binary (alows * classful form as a result). * current code - disallow classful form for IPv4 (due to use of inet_pton). * - freeaddrinfo(NULL). RFC2553 is silent about it. XNET 5.2 says it is * invalid. * current code - SEGV on freeaddrinfo(NULL) * Note: * - We use getipnodebyname() just for thread-safeness. There's no intent * to let it do PF_UNSPEC (actually we never pass PF_UNSPEC to * getipnodebyname(). * - The code filters out AFs that are not supported by the kernel, * when globbing NULL hostname (to loopback, or wildcard). Is it the right * thing to do? What is the relationship with post-RFC2553 AI_ADDRCONFIG * in ai_flags? * - (post-2553) semantics of AI_ADDRCONFIG itself is too vague. * (1) what should we do against numeric hostname (2) what should we do * against NULL hostname (3) what is AI_ADDRCONFIG itself. AF not ready? * non-loopback address configured? global address configured? * - To avoid search order issue, we have a big amount of code duplicate * from gethnamaddr.c and some other places. The issues that there's no * lower layer function to lookup "IPv4 or IPv6" record. Calling * gethostbyname2 from getaddrinfo will end up in wrong search order, as * follows: * - The code makes use of following calls when asked to resolver with * ai_family = PF_UNSPEC: * getipnodebyname(host, AF_INET6); * getipnodebyname(host, AF_INET); * This will result in the following queries if the node is configure to * prefer /etc/hosts than DNS: * lookup /etc/hosts for IPv6 address * lookup DNS for IPv6 address * lookup /etc/hosts for IPv4 address * lookup DNS for IPv4 address * which may not meet people's requirement. * The right thing to happen is to have underlying layer which does * PF_UNSPEC lookup (lookup both) and return chain of addrinfos. * This would result in a bit of code duplicate with _dns_ghbyname() and * friends. */ #include #include #include #include #include #include #include #include #include #include #include "arpa_nameser.h" #include #include #include #include #include "resolv_private.h" #include #include #include #include #include #include #include #include #include "nsswitch.h" #ifdef ANDROID_CHANGES #include #endif /* ANDROID_CHANGES */ typedef union sockaddr_union { struct sockaddr generic; struct sockaddr_in in; struct sockaddr_in6 in6; } sockaddr_union; #define SUCCESS 0 #define ANY 0 #define YES 1 #define NO 0 static const char in_addrany[] = { 0, 0, 0, 0 }; static const char in_loopback[] = { 127, 0, 0, 1 }; #ifdef INET6 static const char in6_addrany[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; static const char in6_loopback[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 }; #endif // This should be synchronized to ResponseCode.h static const int DnsProxyQueryResult = 222; static const struct afd { int a_af; int a_addrlen; int a_socklen; int a_off; const char *a_addrany; const char *a_loopback; int a_scoped; } afdl [] = { #ifdef INET6 {PF_INET6, sizeof(struct in6_addr), sizeof(struct sockaddr_in6), offsetof(struct sockaddr_in6, sin6_addr), in6_addrany, in6_loopback, 1}, #endif {PF_INET, sizeof(struct in_addr), sizeof(struct sockaddr_in), offsetof(struct sockaddr_in, sin_addr), in_addrany, in_loopback, 0}, {0, 0, 0, 0, NULL, NULL, 0}, }; struct explore { int e_af; int e_socktype; int e_protocol; const char *e_protostr; int e_wild; #define WILD_AF(ex) ((ex)->e_wild & 0x01) #define WILD_SOCKTYPE(ex) ((ex)->e_wild & 0x02) #define WILD_PROTOCOL(ex) ((ex)->e_wild & 0x04) }; static const struct explore explore[] = { #if 0 { PF_LOCAL, 0, ANY, ANY, NULL, 0x01 }, #endif #ifdef INET6 { PF_INET6, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_INET6, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_INET6, SOCK_RAW, ANY, NULL, 0x05 }, #endif { PF_INET, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_INET, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_INET, SOCK_RAW, ANY, NULL, 0x05 }, { PF_UNSPEC, SOCK_DGRAM, IPPROTO_UDP, "udp", 0x07 }, { PF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, "tcp", 0x07 }, { PF_UNSPEC, SOCK_RAW, ANY, NULL, 0x05 }, { -1, 0, 0, NULL, 0 }, }; #ifdef INET6 #define PTON_MAX 16 #else #define PTON_MAX 4 #endif static const ns_src default_dns_files[] = { { NSSRC_FILES, NS_SUCCESS }, { NSSRC_DNS, NS_SUCCESS }, { 0, 0 } }; #define MAXPACKET (64*1024) typedef union { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; struct res_target { struct res_target *next; const char *name; /* domain name */ int qclass, qtype; /* class and type of query */ u_char *answer; /* buffer to put answer */ int anslen; /* size of answer buffer */ int n; /* result length */ }; static int str2number(const char *); static int explore_fqdn(const struct addrinfo *, const char *, const char *, struct addrinfo **); static int explore_null(const struct addrinfo *, const char *, struct addrinfo **); static int explore_numeric(const struct addrinfo *, const char *, const char *, struct addrinfo **, const char *); static int explore_numeric_scope(const struct addrinfo *, const char *, const char *, struct addrinfo **); static int get_canonname(const struct addrinfo *, struct addrinfo *, const char *); static struct addrinfo *get_ai(const struct addrinfo *, const struct afd *, const char *); static int get_portmatch(const struct addrinfo *, const char *); static int get_port(const struct addrinfo *, const char *, int); static const struct afd *find_afd(int); #ifdef INET6 static int ip6_str2scopeid(char *, struct sockaddr_in6 *, u_int32_t *); #endif static struct addrinfo *getanswer(const querybuf *, int, const char *, int, const struct addrinfo *); static int _dns_getaddrinfo(void *, void *, va_list); static void _sethtent(FILE **); static void _endhtent(FILE **); static struct addrinfo *_gethtent(FILE **, const char *, const struct addrinfo *); static int _files_getaddrinfo(void *, void *, va_list); static int res_queryN(const char *, struct res_target *, res_state); static int res_searchN(const char *, struct res_target *, res_state); static int res_querydomainN(const char *, const char *, struct res_target *, res_state); static const char * const ai_errlist[] = { "Success", "Address family for hostname not supported", /* EAI_ADDRFAMILY */ "Temporary failure in name resolution", /* EAI_AGAIN */ "Invalid value for ai_flags", /* EAI_BADFLAGS */ "Non-recoverable failure in name resolution", /* EAI_FAIL */ "ai_family not supported", /* EAI_FAMILY */ "Memory allocation failure", /* EAI_MEMORY */ "No address associated with hostname", /* EAI_NODATA */ "hostname nor servname provided, or not known", /* EAI_NONAME */ "servname not supported for ai_socktype", /* EAI_SERVICE */ "ai_socktype not supported", /* EAI_SOCKTYPE */ "System error returned in errno", /* EAI_SYSTEM */ "Invalid value for hints", /* EAI_BADHINTS */ "Resolved protocol is unknown", /* EAI_PROTOCOL */ "Argument buffer overflow", /* EAI_OVERFLOW */ "Unknown error", /* EAI_MAX */ }; /* XXX macros that make external reference is BAD. */ #define GET_AI(ai, afd, addr) \ do { \ /* external reference: pai, error, and label free */ \ (ai) = get_ai(pai, (afd), (addr)); \ if ((ai) == NULL) { \ error = EAI_MEMORY; \ goto free; \ } \ } while (/*CONSTCOND*/0) #define GET_PORT(ai, serv) \ do { \ /* external reference: error and label free */ \ error = get_port((ai), (serv), 0); \ if (error != 0) \ goto free; \ } while (/*CONSTCOND*/0) #define GET_CANONNAME(ai, str) \ do { \ /* external reference: pai, error and label free */ \ error = get_canonname(pai, (ai), (str)); \ if (error != 0) \ goto free; \ } while (/*CONSTCOND*/0) #define ERR(err) \ do { \ /* external reference: error, and label bad */ \ error = (err); \ goto bad; \ /*NOTREACHED*/ \ } while (/*CONSTCOND*/0) #define MATCH_FAMILY(x, y, w) \ ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == PF_UNSPEC || \ (y) == PF_UNSPEC))) #define MATCH(x, y, w) \ ((x) == (y) || (/*CONSTCOND*/(w) && ((x) == ANY || (y) == ANY))) const char * gai_strerror(int ecode) { if (ecode < 0 || ecode > EAI_MAX) ecode = EAI_MAX; return ai_errlist[ecode]; } void freeaddrinfo(struct addrinfo *ai) { struct addrinfo *next; assert(ai != NULL); do { next = ai->ai_next; if (ai->ai_canonname) free(ai->ai_canonname); /* no need to free(ai->ai_addr) */ free(ai); ai = next; } while (ai); } static int str2number(const char *p) { char *ep; unsigned long v; assert(p != NULL); if (*p == '\0') return -1; ep = NULL; errno = 0; v = strtoul(p, &ep, 10); if (errno == 0 && ep && *ep == '\0' && v <= UINT_MAX) return v; else return -1; } /* * Connect a UDP socket to a given unicast address. This will cause no network * traffic, but will fail fast if the system has no or limited reachability to * the destination (e.g., no IPv4 address, no IPv6 default route, ...). */ static int _test_connect(int pf, struct sockaddr *addr, size_t addrlen) { int s = socket(pf, SOCK_DGRAM, IPPROTO_UDP); if (s < 0) return 0; int ret; do { ret = connect(s, addr, addrlen); } while (ret < 0 && errno == EINTR); int success = (ret == 0); do { ret = close(s); } while (ret < 0 && errno == EINTR); return success; } /* * The following functions determine whether IPv4 or IPv6 connectivity is * available in order to implement AI_ADDRCONFIG. * * Strictly speaking, AI_ADDRCONFIG should not look at whether connectivity is * available, but whether addresses of the specified family are "configured * on the local system". However, bionic doesn't currently support getifaddrs, * so checking for connectivity is the next best thing. */ static int _have_ipv6() { static const struct sockaddr_in6 sin6_test = { .sin6_family = AF_INET6, .sin6_addr.s6_addr = { // 2000:: 0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} }; sockaddr_union addr = { .in6 = sin6_test }; return _test_connect(PF_INET6, &addr.generic, sizeof(addr.in6)); } static int _have_ipv4() { static const struct sockaddr_in sin_test = { .sin_family = AF_INET, .sin_addr.s_addr = __constant_htonl(0x08080808L) // 8.8.8.8 }; sockaddr_union addr = { .in = sin_test }; return _test_connect(PF_INET, &addr.generic, sizeof(addr.in)); } // Returns 0 on success, else returns non-zero on error (in which case // getaddrinfo should continue as normal) static int android_getaddrinfo_proxy( const char *hostname, const char *servname, const struct addrinfo *hints, struct addrinfo **res) { int sock; const int one = 1; struct sockaddr_un proxy_addr; const char* cache_mode = getenv("ANDROID_DNS_MODE"); FILE* proxy = NULL; int success = 0; // Clear this at start, as we use its non-NULLness later (in the // error path) to decide if we have to free up any memory we // allocated in the process (before failing). *res = NULL; if (cache_mode != NULL && strcmp(cache_mode, "local") == 0) { // Don't use the proxy in local mode. This is used by the // proxy itself. return -1; } // Temporary cautious hack to disable the DNS proxy for processes // requesting special treatment. Ideally the DNS proxy should // accomodate these apps, though. char propname[PROP_NAME_MAX]; char propvalue[PROP_VALUE_MAX]; snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); if (__system_property_get(propname, propvalue) > 0) { return -1; } // Bogus things we can't serialize. Don't use the proxy. if ((hostname != NULL && strcspn(hostname, " \n\r\t^'\"") != strlen(hostname)) || (servname != NULL && strcspn(servname, " \n\r\t^'\"") != strlen(servname))) { return -1; } sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) { return -1; } setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); memset(&proxy_addr, 0, sizeof(proxy_addr)); proxy_addr.sun_family = AF_UNIX; strlcpy(proxy_addr.sun_path, "/dev/socket/dnsproxyd", sizeof(proxy_addr.sun_path)); if (TEMP_FAILURE_RETRY(connect(sock, (const struct sockaddr*) &proxy_addr, sizeof(proxy_addr))) != 0) { close(sock); return -1; } // Send the request. proxy = fdopen(sock, "r+"); if (fprintf(proxy, "getaddrinfo %s %s %d %d %d %d", hostname == NULL ? "^" : hostname, servname == NULL ? "^" : servname, hints == NULL ? -1 : hints->ai_flags, hints == NULL ? -1 : hints->ai_family, hints == NULL ? -1 : hints->ai_socktype, hints == NULL ? -1 : hints->ai_protocol) < 0) { goto exit; } // literal NULL byte at end, required by FrameworkListener if (fputc(0, proxy) == EOF || fflush(proxy) != 0) { goto exit; } char buf[4]; // read result code for gethostbyaddr if (fread(buf, 1, sizeof(buf), proxy) != sizeof(buf)) { goto exit; } int result_code = (int)strtol(buf, NULL, 10); // verify the code itself if (result_code != DnsProxyQueryResult ) { goto exit; } struct addrinfo* ai = NULL; struct addrinfo** nextres = res; while (1) { uint32_t addrinfo_len; if (fread(&addrinfo_len, sizeof(addrinfo_len), 1, proxy) != 1) { break; } addrinfo_len = ntohl(addrinfo_len); if (addrinfo_len == 0) { success = 1; break; } if (addrinfo_len < sizeof(struct addrinfo)) { break; } struct addrinfo* ai = calloc(1, addrinfo_len + sizeof(struct sockaddr_storage)); if (ai == NULL) { break; } if (fread(ai, addrinfo_len, 1, proxy) != 1) { // Error; fall through. break; } // Zero out the pointer fields we copied which aren't // valid in this address space. ai->ai_addr = NULL; ai->ai_canonname = NULL; ai->ai_next = NULL; // struct sockaddr uint32_t addr_len; if (fread(&addr_len, sizeof(addr_len), 1, proxy) != 1) { break; } addr_len = ntohl(addr_len); if (addr_len != 0) { if (addr_len > sizeof(struct sockaddr_storage)) { // Bogus; too big. break; } struct sockaddr* addr = (struct sockaddr*)(ai + 1); if (fread(addr, addr_len, 1, proxy) != 1) { break; } ai->ai_addr = addr; } // cannonname uint32_t name_len; if (fread(&name_len, sizeof(name_len), 1, proxy) != 1) { break; } name_len = ntohl(name_len); if (name_len != 0) { ai->ai_canonname = (char*) malloc(name_len); if (fread(ai->ai_canonname, name_len, 1, proxy) != 1) { break; } if (ai->ai_canonname[name_len - 1] != '\0') { // The proxy should be returning this // NULL-terminated. break; } } *nextres = ai; nextres = &ai->ai_next; ai = NULL; } if (ai != NULL) { // Clean up partially-built addrinfo that we never ended up // attaching to the response. freeaddrinfo(ai); } exit: if (proxy != NULL) { fclose(proxy); } if (success) { return 0; } // Proxy failed; fall through to local // resolver case. But first clean up any // memory we might've allocated. if (*res) { freeaddrinfo(*res); *res = NULL; } return -1; } int getaddrinfo(const char *hostname, const char *servname, const struct addrinfo *hints, struct addrinfo **res) { struct addrinfo sentinel; struct addrinfo *cur; int error = 0; struct addrinfo ai; struct addrinfo ai0; struct addrinfo *pai; const struct explore *ex; /* hostname is allowed to be NULL */ /* servname is allowed to be NULL */ /* hints is allowed to be NULL */ assert(res != NULL); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; pai = &ai; pai->ai_flags = 0; pai->ai_family = PF_UNSPEC; pai->ai_socktype = ANY; pai->ai_protocol = ANY; pai->ai_addrlen = 0; pai->ai_canonname = NULL; pai->ai_addr = NULL; pai->ai_next = NULL; if (hostname == NULL && servname == NULL) return EAI_NONAME; if (hints) { /* error check for hints */ if (hints->ai_addrlen || hints->ai_canonname || hints->ai_addr || hints->ai_next) ERR(EAI_BADHINTS); /* xxx */ if (hints->ai_flags & ~AI_MASK) ERR(EAI_BADFLAGS); switch (hints->ai_family) { case PF_UNSPEC: case PF_INET: #ifdef INET6 case PF_INET6: #endif break; default: ERR(EAI_FAMILY); } memcpy(pai, hints, sizeof(*pai)); /* * if both socktype/protocol are specified, check if they * are meaningful combination. */ if (pai->ai_socktype != ANY && pai->ai_protocol != ANY) { for (ex = explore; ex->e_af >= 0; ex++) { if (pai->ai_family != ex->e_af) continue; if (ex->e_socktype == ANY) continue; if (ex->e_protocol == ANY) continue; if (pai->ai_socktype == ex->e_socktype && pai->ai_protocol != ex->e_protocol) { ERR(EAI_BADHINTS); } } } } /* * check for special cases. (1) numeric servname is disallowed if * socktype/protocol are left unspecified. (2) servname is disallowed * for raw and other inet{,6} sockets. */ if (MATCH_FAMILY(pai->ai_family, PF_INET, 1) #ifdef PF_INET6 || MATCH_FAMILY(pai->ai_family, PF_INET6, 1) #endif ) { ai0 = *pai; /* backup *pai */ if (pai->ai_family == PF_UNSPEC) { #ifdef PF_INET6 pai->ai_family = PF_INET6; #else pai->ai_family = PF_INET; #endif } error = get_portmatch(pai, servname); if (error) ERR(error); *pai = ai0; } ai0 = *pai; /* NULL hostname, or numeric hostname */ for (ex = explore; ex->e_af >= 0; ex++) { *pai = ai0; /* PF_UNSPEC entries are prepared for DNS queries only */ if (ex->e_af == PF_UNSPEC) continue; if (!MATCH_FAMILY(pai->ai_family, ex->e_af, WILD_AF(ex))) continue; if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) continue; if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) continue; if (pai->ai_family == PF_UNSPEC) pai->ai_family = ex->e_af; if (pai->ai_socktype == ANY && ex->e_socktype != ANY) pai->ai_socktype = ex->e_socktype; if (pai->ai_protocol == ANY && ex->e_protocol != ANY) pai->ai_protocol = ex->e_protocol; if (hostname == NULL) error = explore_null(pai, servname, &cur->ai_next); else error = explore_numeric_scope(pai, hostname, servname, &cur->ai_next); if (error) goto free; while (cur->ai_next) cur = cur->ai_next; } /* * XXX * If numeric representation of AF1 can be interpreted as FQDN * representation of AF2, we need to think again about the code below. */ if (sentinel.ai_next) goto good; if (hostname == NULL) ERR(EAI_NODATA); if (pai->ai_flags & AI_NUMERICHOST) ERR(EAI_NONAME); /* * BEGIN ANDROID CHANGES; proxying to the cache */ if (android_getaddrinfo_proxy(hostname, servname, hints, res) == 0) { return 0; } /* * hostname as alphabetical name. * we would like to prefer AF_INET6 than AF_INET, so we'll make a * outer loop by AFs. */ for (ex = explore; ex->e_af >= 0; ex++) { *pai = ai0; /* require exact match for family field */ if (pai->ai_family != ex->e_af) continue; if (!MATCH(pai->ai_socktype, ex->e_socktype, WILD_SOCKTYPE(ex))) { continue; } if (!MATCH(pai->ai_protocol, ex->e_protocol, WILD_PROTOCOL(ex))) { continue; } if (pai->ai_socktype == ANY && ex->e_socktype != ANY) pai->ai_socktype = ex->e_socktype; if (pai->ai_protocol == ANY && ex->e_protocol != ANY) pai->ai_protocol = ex->e_protocol; error = explore_fqdn(pai, hostname, servname, &cur->ai_next); while (cur && cur->ai_next) cur = cur->ai_next; } /* XXX */ if (sentinel.ai_next) error = 0; if (error) goto free; if (error == 0) { if (sentinel.ai_next) { good: *res = sentinel.ai_next; return SUCCESS; } else error = EAI_FAIL; } free: bad: if (sentinel.ai_next) freeaddrinfo(sentinel.ai_next); *res = NULL; return error; } /* * FQDN hostname, DNS lookup */ static int explore_fqdn(const struct addrinfo *pai, const char *hostname, const char *servname, struct addrinfo **res) { struct addrinfo *result; struct addrinfo *cur; int error = 0; static const ns_dtab dtab[] = { NS_FILES_CB(_files_getaddrinfo, NULL) { NSSRC_DNS, _dns_getaddrinfo, NULL }, /* force -DHESIOD */ NS_NIS_CB(_yp_getaddrinfo, NULL) { 0, 0, 0 } }; assert(pai != NULL); /* hostname may be NULL */ /* servname may be NULL */ assert(res != NULL); result = NULL; /* * if the servname does not match socktype/protocol, ignore it. */ if (get_portmatch(pai, servname) != 0) return 0; switch (nsdispatch(&result, dtab, NSDB_HOSTS, "getaddrinfo", default_dns_files, hostname, pai)) { case NS_TRYAGAIN: error = EAI_AGAIN; goto free; case NS_UNAVAIL: error = EAI_FAIL; goto free; case NS_NOTFOUND: error = EAI_NODATA; goto free; case NS_SUCCESS: error = 0; for (cur = result; cur; cur = cur->ai_next) { GET_PORT(cur, servname); /* canonname should be filled already */ } break; } *res = result; return 0; free: if (result) freeaddrinfo(result); return error; } /* * 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; 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, 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); /* xxx meaningless? * GET_CANONNAME(cur->ai_next, "anyaddr"); */ GET_PORT(cur->ai_next, servname); } else { GET_AI(cur->ai_next, afd, afd->a_loopback); /* xxx meaningless? * GET_CANONNAME(cur->ai_next, "localhost"); */ GET_PORT(cur->ai_next, servname); } cur = cur->ai_next; *res = sentinel.ai_next; return 0; free: if (sentinel.ai_next) 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; switch (afd->a_af) { #if 0 /*X/Open spec*/ case AF_INET: if (inet_aton(hostname, (struct in_addr *)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. */ GET_CANONNAME(cur->ai_next, canonname); } while (cur && cur->ai_next) cur = cur->ai_next; } else ERR(EAI_FAMILY); /*xxx*/ } break; #endif default: 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. */ GET_CANONNAME(cur->ai_next, canonname); } while (cur->ai_next) cur = cur->ai_next; } else ERR(EAI_FAMILY); /*xxx*/ } break; } *res = sentinel.ai_next; return 0; free: bad: if (sentinel.ai_next) 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) { #if !defined(SCOPE_DELIMITER) || !defined(INET6) return explore_numeric(pai, hostname, servname, res, hostname); #else const struct afd *afd; struct addrinfo *cur; int error; char *cp, *hostname2 = NULL, *scope, *addr; struct sockaddr_in6 *sin6; 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 */ 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) { u_int32_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; #endif } 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) + (afd->a_socklen)); if (ai == NULL) return NULL; memcpy(ai, pai, sizeof(struct addrinfo)); ai->ai_addr = (struct sockaddr *)(void *)(ai + 1); memset(ai->ai_addr, 0, (size_t)afd->a_socklen); #ifdef HAVE_SA_LEN ai->ai_addr->sa_len = afd->a_socklen; #endif ai->ai_addrlen = afd->a_socklen; #if defined (__alpha__) || (defined(__i386__) && defined(_LP64)) || defined(__sparc64__) ai->__ai_pad0 = 0; #endif 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: #ifdef AF_INET6 case AF_INET6: #endif break; default: return 0; } switch (ai->ai_socktype) { case SOCK_RAW: return EAI_SERVICE; case SOCK_DGRAM: case SOCK_STREAM: allownumeric = 1; break; case ANY: #if 1 /* ANDROID-SPECIFIC CHANGE TO MATCH GLIBC */ allownumeric = 1; #else allownumeric = 0; #endif 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; #ifdef INET6 case AF_INET6: ((struct sockaddr_in6 *)(void *) ai->ai_addr)->sin6_port = port; break; #endif } } 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; } #ifdef INET6 /* convert a string to a scope identifier. XXX: IPv6 specific */ static int ip6_str2scopeid(char *scope, struct sockaddr_in6 *sin6, u_int32_t *scopeid) { u_long 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) goto trynumeric; return 0; } /* still unclear about literal, allow numeric only - placeholder */ if (IN6_IS_ADDR_SITELOCAL(a6) || IN6_IS_ADDR_MC_SITELOCAL(a6)) goto trynumeric; if (IN6_IS_ADDR_MC_ORGLOCAL(a6)) goto trynumeric; else goto trynumeric; /* global */ /* try to convert to a numeric id as a last resort */ trynumeric: errno = 0; lscopeid = strtoul(scope, &ep, 10); *scopeid = (u_int32_t)(lscopeid & 0xffffffffUL); if (errno == 0 && ep && *ep == '\0' && *scopeid == lscopeid) return 0; else return -1; } #endif /* code duplicate with gethnamaddr.c */ static const char AskedForGot[] = "gethostby*.getanswer: asked for \"%s\", got \"%s\""; static struct addrinfo * getanswer(const querybuf *answer, int anslen, const char *qname, int qtype, const struct addrinfo *pai) { struct addrinfo sentinel, *cur; struct addrinfo ai; const struct afd *afd; char *canonname; const HEADER *hp; const u_char *cp; int n; const u_char *eom; char *bp, *ep; int type, class, ancount, qdcount; int haveanswer, had_error; char tbuf[MAXDNAME]; int (*name_ok) (const char *); char hostbuf[8*1024]; assert(answer != NULL); assert(qname != NULL); assert(pai != NULL); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; canonname = NULL; eom = answer->buf + anslen; 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 = &answer->hdr; ancount = ntohs(hp->ancount); qdcount = ntohs(hp->qdcount); bp = hostbuf; ep = hostbuf + sizeof hostbuf; cp = answer->buf + HFIXEDSZ; if (qdcount != 1) { h_errno = NO_RECOVERY; return (NULL); } n = dn_expand(answer->buf, eom, cp, bp, ep - bp); if ((n < 0) || !(*name_ok)(bp)) { h_errno = NO_RECOVERY; return (NULL); } cp += 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) { h_errno = 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->buf, eom, cp, bp, ep - bp); if ((n < 0) || !(*name_ok)(bp)) { had_error++; continue; } cp += n; /* name */ type = _getshort(cp); cp += INT16SZ; /* type */ class = _getshort(cp); cp += INT16SZ + INT32SZ; /* class, TTL */ n = _getshort(cp); cp += INT16SZ; /* len */ if (class != 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->buf, 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) syslog(LOG_NOTICE|LOG_AUTH, "gethostby*.getanswer: asked for \"%s %s %s\", got type \"%s\"", qname, p_class(C_IN), p_type(qtype), p_type(type)); cp += n; continue; /* XXX - had_error++ ? */ } switch (type) { case T_A: case T_AAAA: if (strcasecmp(canonname, bp) != 0) { syslog(LOG_NOTICE|LOG_AUTH, AskedForGot, canonname, 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); h_errno = NETDB_SUCCESS; return sentinel.ai_next; } h_errno = NO_RECOVERY; return NULL; } struct addrinfo_sort_elem { struct addrinfo *ai; int has_src_addr; sockaddr_union src_addr; int original_order; }; /*ARGSUSED*/ 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 { /* * According to draft-ietf-6man-rfc3484-revise-01 section 2.3, * it is best not to treat the private IPv4 ranges * (10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16) as being * in a special scope, so we don't. */ 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 . */ /* 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 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01. */ /*ARGSUSED*/ static int _get_label(const struct sockaddr *addr) { if (addr->sa_family == AF_INET) { return 3; } 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_ULA(&addr6->sin6_addr)) { return 1; } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { return 3; } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { return 4; } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { return 5; } else if (IN6_IS_ADDR_V4COMPAT(&addr6->sin6_addr)) { return 10; } else if (IN6_IS_ADDR_SITELOCAL(&addr6->sin6_addr)) { return 11; } else if (IN6_IS_ADDR_6BONE(&addr6->sin6_addr)) { return 12; } else { return 2; } } 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 3484, section 2.1, plus changes from draft-ietf-6man-rfc3484-revise-01. */ /*ARGSUSED*/ static int _get_precedence(const struct sockaddr *addr) { if (addr->sa_family == AF_INET) { return 30; } 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 60; } else if (IN6_IS_ADDR_ULA(&addr6->sin6_addr)) { return 50; } else if (IN6_IS_ADDR_V4MAPPED(&addr6->sin6_addr)) { return 30; } else if (IN6_IS_ADDR_6TO4(&addr6->sin6_addr)) { return 20; } else if (IN6_IS_ADDR_TEREDO(&addr6->sin6_addr)) { return 10; } 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 { return 40; } } else { return 1; } } /* * Find number of matching initial bits between the two addresses a1 and a2. */ /*ARGSUSED*/ 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 3484, section 6. */ /*ARGSUSED*/ static int _rfc3484_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.generic); scope_dst1 = _get_scope(a1->ai->ai_addr); scope_match1 = (scope_src1 == scope_dst1); scope_src2 = _get_scope(&a2->src_addr.generic); 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.generic); label_dst1 = _get_label(a1->ai->ai_addr); label_match1 = (label_src1 == label_dst1); label_src2 = _get_label(&a2->src_addr.generic); 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 3484 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.in6; const struct sockaddr_in6 *a1_dst = (const struct sockaddr_in6 *)a1->ai->ai_addr; const struct sockaddr_in6 *a2_src = &a2->src_addr.in6; 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. */ /*ARGSUSED*/ static int _find_src_addr(const struct sockaddr *addr, struct sockaddr *src_addr) { 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, IPPROTO_UDP); if (sock == -1) { if (errno == EAFNOSUPPORT) { return 0; } else { return -1; } } do { ret = connect(sock, addr, len); } while (ret == -1 && errno == EINTR); if (ret == -1) { close(sock); return 0; } if (getsockname(sock, src_addr, &len) == -1) { close(sock); return -1; } close(sock); return 1; } /* * Sort the linked list starting at sentinel->ai_next in RFC3484 order. * Will leave the list unchanged if an error occurs. */ /*ARGSUSED*/ static void _rfc3484_sort(struct addrinfo *list_sentinel) { 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.generic); 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), _rfc3484_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 _using_alt_dns() { char propname[PROP_NAME_MAX]; char propvalue[PROP_VALUE_MAX]; propvalue[0] = 0; snprintf(propname, sizeof(propname), "net.dns1.%d", getpid()); if (__system_property_get(propname, propvalue) > 0 ) { return 1; } return 0; } /*ARGSUSED*/ static int _dns_getaddrinfo(void *rv, void *cb_data, va_list ap) { struct addrinfo *ai; querybuf *buf, *buf2; const char *name; const struct addrinfo *pai; struct addrinfo sentinel, *cur; struct res_target q, q2; res_state res; name = va_arg(ap, char *); pai = va_arg(ap, const struct addrinfo *); //fprintf(stderr, "_dns_getaddrinfo() name = '%s'\n", name); memset(&q, 0, sizeof(q)); memset(&q2, 0, sizeof(q2)); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; buf = malloc(sizeof(*buf)); if (buf == NULL) { h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } buf2 = malloc(sizeof(*buf2)); if (buf2 == NULL) { free(buf); h_errno = NETDB_INTERNAL; return NS_NOTFOUND; } switch (pai->ai_family) { case AF_UNSPEC: /* prefer IPv6 */ q.name = name; q.qclass = C_IN; q.answer = buf->buf; q.anslen = sizeof(buf->buf); int query_ipv6 = 1, query_ipv4 = 1; if (pai->ai_flags & AI_ADDRCONFIG) { // Only implement AI_ADDRCONFIG if the application is not // using its own DNS servers, since our implementation // only works on the default connection. if (!_using_alt_dns()) { query_ipv6 = _have_ipv6(); query_ipv4 = _have_ipv4(); } } if (query_ipv6) { q.qtype = T_AAAA; if (query_ipv4) { q.next = &q2; q2.name = name; q2.qclass = C_IN; q2.qtype = T_A; q2.answer = buf2->buf; q2.anslen = sizeof(buf2->buf); } } else if (query_ipv4) { q.qtype = T_A; } else { free(buf); free(buf2); return NS_NOTFOUND; } break; case AF_INET: q.name = name; q.qclass = C_IN; q.qtype = T_A; q.answer = buf->buf; q.anslen = sizeof(buf->buf); break; case AF_INET6: q.name = name; q.qclass = C_IN; q.qtype = T_AAAA; q.answer = buf->buf; q.anslen = sizeof(buf->buf); break; default: free(buf); free(buf2); return NS_UNAVAIL; } res = __res_get_state(); if (res == NULL) { free(buf); free(buf2); return NS_NOTFOUND; } if (res_searchN(name, &q, res) < 0) { __res_put_state(res); free(buf); free(buf2); return NS_NOTFOUND; } ai = getanswer(buf, q.n, q.name, q.qtype, pai); if (ai) { cur->ai_next = ai; while (cur && cur->ai_next) cur = cur->ai_next; } if (q.next) { ai = getanswer(buf2, q2.n, q2.name, q2.qtype, pai); if (ai) cur->ai_next = ai; } free(buf); free(buf2); if (sentinel.ai_next == NULL) { __res_put_state(res); switch (h_errno) { case HOST_NOT_FOUND: return NS_NOTFOUND; case TRY_AGAIN: return NS_TRYAGAIN; default: return NS_UNAVAIL; } } _rfc3484_sort(&sentinel); __res_put_state(res); *((struct addrinfo **)rv) = sentinel.ai_next; return NS_SUCCESS; } static void _sethtent(FILE **hostf) { if (!*hostf) *hostf = fopen(_PATH_HOSTS, "r" ); 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 hints, *res0, *res; int error; const char *addr; char hostbuf[8*1024]; // fprintf(stderr, "_gethtent() name = '%s'\n", name); assert(name != NULL); assert(pai != NULL); if (!*hostf && !(*hostf = fopen(_PATH_HOSTS, "r" ))) 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'; // fprintf(stderr, "\ttname = '%s'", tname); if (strcasecmp(name, tname) == 0) goto found; } goto again; found: hints = *pai; hints.ai_flags = AI_NUMERICHOST; error = getaddrinfo(addr, NULL, &hints, &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; } /*ARGSUSED*/ static int _files_getaddrinfo(void *rv, void *cb_data, va_list ap) { const char *name; const struct addrinfo *pai; struct addrinfo sentinel, *cur; struct addrinfo *p; FILE *hostf = NULL; name = va_arg(ap, char *); pai = va_arg(ap, struct addrinfo *); // fprintf(stderr, "_files_getaddrinfo() name = '%s'\n", name); memset(&sentinel, 0, sizeof(sentinel)); cur = &sentinel; _sethtent(&hostf); while ((p = _gethtent(&hostf, name, pai)) != NULL) { cur->ai_next = p; while (cur && cur->ai_next) cur = cur->ai_next; } _endhtent(&hostf); *((struct addrinfo **)rv) = sentinel.ai_next; if (sentinel.ai_next == NULL) return NS_NOTFOUND; return NS_SUCCESS; } /* resolver logic */ /* * 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 h_errno. * * Caller must parse answer and determine whether it answers the question. */ static int res_queryN(const char *name, /* domain name */ struct res_target *target, res_state res) { u_char buf[MAXPACKET]; HEADER *hp; 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) { int class, type; u_char *answer; int anslen; hp = (HEADER *)(void *)t->answer; hp->rcode = NOERROR; /* default */ /* make it easier... */ class = t->qclass; type = t->qtype; answer = t->answer; anslen = t->anslen; #ifdef DEBUG if (res->options & RES_DEBUG) printf(";; res_nquery(%s, %d, %d)\n", name, class, type); #endif n = res_nmkquery(res, QUERY, name, class, type, NULL, 0, NULL, buf, sizeof(buf)); #ifdef RES_USE_EDNS0 if (n > 0 && (res->options & RES_USE_EDNS0) != 0) n = res_nopt(res, n, buf, sizeof(buf), anslen); #endif if (n <= 0) { #ifdef DEBUG if (res->options & RES_DEBUG) printf(";; res_nquery: mkquery failed\n"); #endif h_errno = NO_RECOVERY; return n; } n = res_nsend(res, buf, n, answer, anslen); #if 0 if (n < 0) { #ifdef DEBUG if (res->options & RES_DEBUG) printf(";; res_query: send error\n"); #endif h_errno = TRY_AGAIN; return n; } #endif if (n < 0 || hp->rcode != NOERROR || ntohs(hp->ancount) == 0) { rcode = hp->rcode; /* record most recent error */ #ifdef DEBUG if (res->options & RES_DEBUG) printf(";; rcode = %u, ancount=%u\n", hp->rcode, ntohs(hp->ancount)); #endif continue; } ancount += ntohs(hp->ancount); t->n = n; } if (ancount == 0) { switch (rcode) { case NXDOMAIN: h_errno = HOST_NOT_FOUND; break; case SERVFAIL: h_errno = TRY_AGAIN; break; case NOERROR: h_errno = NO_DATA; break; case FORMERR: case NOTIMP: case REFUSED: default: h_errno = NO_RECOVERY; break; } 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 h_errno. */ static int res_searchN(const char *name, struct res_target *target, res_state res) { const char *cp, * const *domain; HEADER *hp; u_int dots; int trailing_dot, 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; /*XXX*/ errno = 0; h_errno = HOST_NOT_FOUND; /* default, if we never query */ dots = 0; for (cp = name; *cp; cp++) dots += (*cp == '.'); trailing_dot = 0; if (cp > name && *--cp == '.') trailing_dot++; //fprintf(stderr, "res_searchN() name = '%s'\n", name); /* * if there aren't any dots, it could be a user-level alias */ if (!dots && (cp = __hostalias(name)) != NULL) { ret = res_queryN(cp, target, res); return ret; } /* * 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); if (ret > 0) return (ret); saved_herrno = h_errno; tried_as_is++; } /* * We do at least one level of search if * - there is no dot and RES_DEFNAME is set, or * - there is at least one dot, there is no trailing dot, * and RES_DNSRCH is set. */ if ((!dots && (res->options & RES_DEFNAMES)) || (dots && !trailing_dot && (res->options & RES_DNSRCH))) { int done = 0; for (domain = (const char * const *)res->dnsrch; *domain && !done; domain++) { ret = res_querydomainN(name, *domain, target, res); 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) { h_errno = TRY_AGAIN; return -1; } switch (h_errno) { 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 got here for some reason other than DNSRCH, * we only wanted one iteration of the loop, so stop. */ if (!(res->options & RES_DNSRCH)) 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); 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) h_errno = saved_herrno; else if (got_nodata) h_errno = NO_DATA; else if (got_servfail) h_errno = 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, struct res_target *target, res_state res) { char nbuf[MAXDNAME]; const char *longname = nbuf; size_t n, d; assert(name != NULL); /* XXX: target may be NULL??? */ #ifdef DEBUG if (res->options & RES_DEBUG) printf(";; res_querydomain(%s, %s)\n", name, domain?domain:""); #endif if (domain == NULL) { /* * Check for trailing '.'; * copy without '.' if present. */ n = strlen(name); if (n + 1 > sizeof(nbuf)) { h_errno = 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)) { h_errno = NO_RECOVERY; return -1; } snprintf(nbuf, sizeof(nbuf), "%s.%s", name, domain); } return res_queryN(longname, target, res); }