/* $OpenBSD: getaddrinfo_async.c,v 1.63 2024/08/21 05:53:10 florian Exp $ */ /* * Copyright (c) 2012 Eric Faurot * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "asr_private.h" struct match { int family; int socktype; int protocol; }; static int getaddrinfo_async_run(struct asr_query *, struct asr_result *); static int get_port(const char *, const char *, int); static int iter_family(struct asr_query *, int); static int addrinfo_add(struct asr_query *, const struct sockaddr *, const char *); static int addrinfo_from_file(struct asr_query *, int, FILE *); static int addrinfo_from_pkt(struct asr_query *, char *, size_t); static int addrconfig_setup(struct asr_query *); static const struct match matches[] = { { PF_INET, SOCK_DGRAM, IPPROTO_UDP }, { PF_INET, SOCK_STREAM, IPPROTO_TCP }, { PF_INET, SOCK_RAW, 0 }, { PF_INET6, SOCK_DGRAM, IPPROTO_UDP }, { PF_INET6, SOCK_STREAM, IPPROTO_TCP }, { PF_INET6, SOCK_RAW, 0 }, { -1, 0, 0, }, }; #define MATCH_FAMILY(a, b) ((a) == matches[(b)].family || (a) == PF_UNSPEC) #define MATCH_PROTO(a, b) ((a) == matches[(b)].protocol || (a) == 0 || matches[(b)].protocol == 0) /* Do not match SOCK_RAW unless explicitly specified */ #define MATCH_SOCKTYPE(a, b) ((a) == matches[(b)].socktype || ((a) == 0 && \ matches[(b)].socktype != SOCK_RAW)) enum { DOM_INIT, DOM_DOMAIN, DOM_DONE }; struct asr_query * getaddrinfo_async(const char *hostname, const char *servname, const struct addrinfo *hints, void *asr) { struct asr_ctx *ac; struct asr_query *as; if (hints == NULL || (hints->ai_flags & AI_NUMERICHOST) == 0) ac = _asr_use_resolver(asr); else ac = _asr_no_resolver(); if ((as = _asr_async_new(ac, ASR_GETADDRINFO)) == NULL) goto abort; /* errno set */ as->as_run = getaddrinfo_async_run; if (hostname) { if ((as->as.ai.hostname = strdup(hostname)) == NULL) goto abort; /* errno set */ } if (servname && (as->as.ai.servname = strdup(servname)) == NULL) goto abort; /* errno set */ if (hints) memmove(&as->as.ai.hints, hints, sizeof *hints); else { memset(&as->as.ai.hints, 0, sizeof as->as.ai.hints); as->as.ai.hints.ai_family = PF_UNSPEC; as->as.ai.hints.ai_flags = AI_ADDRCONFIG; } _asr_ctx_unref(ac); return (as); abort: if (as) _asr_async_free(as); _asr_ctx_unref(ac); return (NULL); } DEF_WEAK(getaddrinfo_async); static int getaddrinfo_async_run(struct asr_query *as, struct asr_result *ar) { char fqdn[MAXDNAME]; const char *str; struct addrinfo *ai; int i, family, r, is_localhost = 0; FILE *f; union { struct sockaddr sa; struct sockaddr_in sain; struct sockaddr_in6 sain6; } sa; next: switch (as->as_state) { case ASR_STATE_INIT: /* * First, make sure the parameters are valid. */ as->as_count = 0; if (as->as.ai.hostname == NULL && as->as.ai.servname == NULL) { ar->ar_gai_errno = EAI_NONAME; async_set_state(as, ASR_STATE_HALT); break; } if (as->as.ai.hostname && as->as.ai.hostname[0] == '\0') { ar->ar_gai_errno = EAI_NODATA; async_set_state(as, ASR_STATE_HALT); break; } ai = &as->as.ai.hints; if (ai->ai_addrlen || ai->ai_canonname || ai->ai_addr || ai->ai_next) { ar->ar_gai_errno = EAI_BADHINTS; async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_flags & ~AI_MASK || (ai->ai_flags & AI_CANONNAME && ai->ai_flags & AI_FQDN)) { ar->ar_gai_errno = EAI_BADFLAGS; async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_family != PF_UNSPEC && ai->ai_family != PF_INET && ai->ai_family != PF_INET6) { ar->ar_gai_errno = EAI_FAMILY; async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_socktype && ai->ai_socktype != SOCK_DGRAM && ai->ai_socktype != SOCK_STREAM && ai->ai_socktype != SOCK_RAW) { ar->ar_gai_errno = EAI_SOCKTYPE; async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_socktype == SOCK_RAW && get_port(as->as.ai.servname, NULL, 1) != 0) { ar->ar_gai_errno = EAI_SERVICE; async_set_state(as, ASR_STATE_HALT); break; } /* Restrict result set to configured address families */ if (ai->ai_flags & AI_ADDRCONFIG) { if (addrconfig_setup(as) == -1) { ar->ar_errno = errno; ar->ar_gai_errno = EAI_SYSTEM; async_set_state(as, ASR_STATE_HALT); break; } } /* Make sure there is at least a valid combination */ for (i = 0; matches[i].family != -1; i++) if (MATCH_FAMILY(ai->ai_family, i) && MATCH_SOCKTYPE(ai->ai_socktype, i) && MATCH_PROTO(ai->ai_protocol, i)) break; if (matches[i].family == -1) { ar->ar_gai_errno = EAI_BADHINTS; async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_protocol == 0 || ai->ai_protocol == IPPROTO_UDP) as->as.ai.port_udp = get_port(as->as.ai.servname, "udp", as->as.ai.hints.ai_flags & AI_NUMERICSERV); if (ai->ai_protocol == 0 || ai->ai_protocol == IPPROTO_TCP) as->as.ai.port_tcp = get_port(as->as.ai.servname, "tcp", as->as.ai.hints.ai_flags & AI_NUMERICSERV); if (as->as.ai.port_tcp == -2 || as->as.ai.port_udp == -2 || (as->as.ai.port_tcp == -1 && as->as.ai.port_udp == -1) || (ai->ai_protocol && (as->as.ai.port_udp == -1 || as->as.ai.port_tcp == -1))) { ar->ar_gai_errno = EAI_SERVICE; async_set_state(as, ASR_STATE_HALT); break; } ar->ar_gai_errno = 0; if (!(ai->ai_flags & AI_NUMERICHOST)) is_localhost = _asr_is_localhost(as->as.ai.hostname); /* * If hostname is NULL, "localhost" or falls within the * ".localhost." domain, use local address. * RFC 6761, 6.3: * 3. Name resolution APIs and libraries SHOULD recognize * localhost names as special and SHOULD always return the IP * loopback address for address queries and negative responses * for all other query types. Name resolution APIs SHOULD NOT * send queries for localhost names to their configured caching * DNS server(s). */ if (as->as.ai.hostname == NULL || is_localhost) { for (family = iter_family(as, 1); family != -1; family = iter_family(as, 0)) { /* * We could use statically built sockaddrs for * those, rather than parsing over and over. */ if (family == PF_INET) str = (ai->ai_flags & AI_PASSIVE && !is_localhost) ? "0.0.0.0" : "127.0.0.1"; else /* PF_INET6 */ str = (ai->ai_flags & AI_PASSIVE && !is_localhost) ? "::" : "::1"; /* This can't fail */ _asr_sockaddr_from_str(&sa.sa, family, str); if ((r = addrinfo_add(as, &sa.sa, "localhost."))) { ar->ar_gai_errno = r; break; } } if (ar->ar_gai_errno == 0 && as->as_count == 0) { ar->ar_gai_errno = EAI_NODATA; } async_set_state(as, ASR_STATE_HALT); break; } /* Try numeric addresses first */ for (family = iter_family(as, 1); family != -1; family = iter_family(as, 0)) { if (_asr_sockaddr_from_str(&sa.sa, family, as->as.ai.hostname) == -1) continue; if ((r = addrinfo_add(as, &sa.sa, as->as.ai.hostname))) ar->ar_gai_errno = r; break; } if (ar->ar_gai_errno || as->as_count) { async_set_state(as, ASR_STATE_HALT); break; } if (ai->ai_flags & AI_NUMERICHOST) { ar->ar_gai_errno = EAI_NONAME; async_set_state(as, ASR_STATE_HALT); break; } /* make sure there are no funny characters in hostname */ if (!hnok_lenient(as->as.ai.hostname)) { ar->ar_gai_errno = EAI_FAIL; async_set_state(as, ASR_STATE_HALT); break; } async_set_state(as, ASR_STATE_NEXT_DB); break; case ASR_STATE_NEXT_DB: if (_asr_iter_db(as) == -1) { async_set_state(as, ASR_STATE_NOT_FOUND); break; } as->as_family_idx = 0; async_set_state(as, ASR_STATE_SAME_DB); break; case ASR_STATE_NEXT_FAMILY: as->as_family_idx += 1; if (as->as.ai.hints.ai_family != AF_UNSPEC || AS_FAMILY(as) == -1) { /* The family was specified, or we have tried all * families with this DB. */ if (as->as_count) { ar->ar_gai_errno = 0; async_set_state(as, ASR_STATE_HALT); } else async_set_state(as, ASR_STATE_NEXT_DOMAIN); break; } async_set_state(as, ASR_STATE_SAME_DB); break; case ASR_STATE_NEXT_DOMAIN: /* domain search is only for dns */ if (AS_DB(as) != ASR_DB_DNS) { async_set_state(as, ASR_STATE_NEXT_DB); break; } as->as_family_idx = 0; free(as->as.ai.fqdn); as->as.ai.fqdn = NULL; r = _asr_iter_domain(as, as->as.ai.hostname, fqdn, sizeof(fqdn)); if (r == -1) { async_set_state(as, ASR_STATE_NEXT_DB); break; } if (r == 0) { ar->ar_gai_errno = EAI_FAIL; async_set_state(as, ASR_STATE_HALT); break; } as->as.ai.fqdn = strdup(fqdn); if (as->as.ai.fqdn == NULL) { ar->ar_gai_errno = EAI_MEMORY; async_set_state(as, ASR_STATE_HALT); break; } async_set_state(as, ASR_STATE_SAME_DB); break; case ASR_STATE_SAME_DB: /* query the current DB again */ switch (AS_DB(as)) { case ASR_DB_DNS: if (as->as.ai.fqdn == NULL) { /* First try, initialize domain iteration */ as->as_dom_flags = 0; as->as_dom_step = DOM_INIT; async_set_state(as, ASR_STATE_NEXT_DOMAIN); break; } family = (as->as.ai.hints.ai_family == AF_UNSPEC) ? AS_FAMILY(as) : as->as.ai.hints.ai_family; if (family == AF_INET && as->as_flags & ASYNC_NO_INET) { async_set_state(as, ASR_STATE_NEXT_FAMILY); break; } else if (family == AF_INET6 && as->as_flags & ASYNC_NO_INET6) { async_set_state(as, ASR_STATE_NEXT_FAMILY); break; } as->as_subq = _res_query_async_ctx(as->as.ai.fqdn, C_IN, (family == AF_INET6) ? T_AAAA : T_A, as->as_ctx); if (as->as_subq == NULL) { if (errno == ENOMEM) ar->ar_gai_errno = EAI_MEMORY; else ar->ar_gai_errno = EAI_FAIL; async_set_state(as, ASR_STATE_HALT); break; } async_set_state(as, ASR_STATE_SUBQUERY); break; case ASR_DB_FILE: f = fopen(_PATH_HOSTS, "re"); if (f == NULL) { async_set_state(as, ASR_STATE_NEXT_DB); break; } family = (as->as.ai.hints.ai_family == AF_UNSPEC) ? AS_FAMILY(as) : as->as.ai.hints.ai_family; r = addrinfo_from_file(as, family, f); if (r == -1) { if (errno == ENOMEM) ar->ar_gai_errno = EAI_MEMORY; else ar->ar_gai_errno = EAI_FAIL; async_set_state(as, ASR_STATE_HALT); } else async_set_state(as, ASR_STATE_NEXT_FAMILY); fclose(f); break; default: async_set_state(as, ASR_STATE_NEXT_DB); } break; case ASR_STATE_SUBQUERY: if ((r = asr_run(as->as_subq, ar)) == ASYNC_COND) return (ASYNC_COND); as->as_subq = NULL; if (ar->ar_datalen == -1) { async_set_state(as, ASR_STATE_NEXT_FAMILY); break; } r = addrinfo_from_pkt(as, ar->ar_data, ar->ar_datalen); if (r == -1) { if (errno == ENOMEM) ar->ar_gai_errno = EAI_MEMORY; else ar->ar_gai_errno = EAI_FAIL; async_set_state(as, ASR_STATE_HALT); } else async_set_state(as, ASR_STATE_NEXT_FAMILY); free(ar->ar_data); break; case ASR_STATE_NOT_FOUND: /* No result found. Maybe we can try again. */ if (as->as_flags & ASYNC_AGAIN) ar->ar_gai_errno = EAI_AGAIN; else ar->ar_gai_errno = EAI_NODATA; async_set_state(as, ASR_STATE_HALT); break; case ASR_STATE_HALT: if (ar->ar_gai_errno == 0) { ar->ar_count = as->as_count; ar->ar_addrinfo = as->as.ai.aifirst; as->as.ai.aifirst = NULL; } else { ar->ar_count = 0; ar->ar_addrinfo = NULL; } return (ASYNC_DONE); default: ar->ar_errno = EOPNOTSUPP; ar->ar_gai_errno = EAI_SYSTEM; async_set_state(as, ASR_STATE_HALT); break; } goto next; } /* * Retrieve the port number for the service name "servname" and * the protocol "proto". */ static int get_port(const char *servname, const char *proto, int numonly) { struct servent se; struct servent_data sed; int port; const char *e; if (servname == NULL) return (0); e = NULL; port = strtonum(servname, 0, USHRT_MAX, &e); if (e == NULL) return (port); if (errno == ERANGE) return (-2); /* invalid */ if (numonly) return (-2); port = -1; memset(&sed, 0, sizeof(sed)); if (getservbyname_r(servname, proto, &se, &sed) != -1) port = ntohs(se.s_port); endservent_r(&sed); return (port); } /* * Iterate over the address families that are to be queried. Use the * list on the async context, unless a specific family was given in hints. */ static int iter_family(struct asr_query *as, int first) { if (first) { as->as_family_idx = 0; if (as->as.ai.hints.ai_family != PF_UNSPEC) return as->as.ai.hints.ai_family; return AS_FAMILY(as); } if (as->as.ai.hints.ai_family != PF_UNSPEC) return (-1); as->as_family_idx++; return AS_FAMILY(as); } /* * Use the sockaddr at "sa" to extend the result list on the "as" context, * with the specified canonical name "cname". This function adds one * entry per protocol/socktype match. */ static int addrinfo_add(struct asr_query *as, const struct sockaddr *sa, const char *cname) { struct addrinfo *ai; int i, port, proto; for (i = 0; matches[i].family != -1; i++) { if (matches[i].family != sa->sa_family || !MATCH_SOCKTYPE(as->as.ai.hints.ai_socktype, i) || !MATCH_PROTO(as->as.ai.hints.ai_protocol, i)) continue; proto = as->as.ai.hints.ai_protocol; if (!proto) proto = matches[i].protocol; if (proto == IPPROTO_TCP) port = as->as.ai.port_tcp; else if (proto == IPPROTO_UDP) port = as->as.ai.port_udp; else port = 0; /* servname specified, but not defined for this protocol */ if (port == -1) continue; ai = calloc(1, sizeof(*ai) + sa->sa_len); if (ai == NULL) return (EAI_MEMORY); ai->ai_family = sa->sa_family; ai->ai_socktype = matches[i].socktype; ai->ai_protocol = proto; ai->ai_flags = as->as.ai.hints.ai_flags; ai->ai_addrlen = sa->sa_len; ai->ai_addr = (void *)(ai + 1); if (cname && as->as.ai.hints.ai_flags & (AI_CANONNAME | AI_FQDN)) { if ((ai->ai_canonname = strdup(cname)) == NULL) { free(ai); return (EAI_MEMORY); } } memmove(ai->ai_addr, sa, sa->sa_len); if (sa->sa_family == PF_INET) ((struct sockaddr_in *)ai->ai_addr)->sin_port = htons(port); else if (sa->sa_family == PF_INET6) ((struct sockaddr_in6 *)ai->ai_addr)->sin6_port = htons(port); if (as->as.ai.aifirst == NULL) as->as.ai.aifirst = ai; if (as->as.ai.ailast) as->as.ai.ailast->ai_next = ai; as->as.ai.ailast = ai; as->as_count += 1; } return (0); } static int addrinfo_from_file(struct asr_query *as, int family, FILE *f) { char *tokens[MAXTOKEN], *c, buf[BUFSIZ + 1]; int n, i; union { struct sockaddr sa; struct sockaddr_in sain; struct sockaddr_in6 sain6; } u; for (;;) { n = _asr_parse_namedb_line(f, tokens, MAXTOKEN, buf, sizeof(buf)); if (n == -1) break; /* ignore errors reading the file */ for (i = 1; i < n; i++) { if (strcasecmp(as->as.ai.hostname, tokens[i])) continue; if (_asr_sockaddr_from_str(&u.sa, family, tokens[0]) == -1) continue; break; } if (i == n) continue; if (as->as.ai.hints.ai_flags & (AI_CANONNAME | AI_FQDN)) c = tokens[1]; else c = NULL; if (addrinfo_add(as, &u.sa, c)) return (-1); /* errno set */ } return (0); } static int addrinfo_from_pkt(struct asr_query *as, char *pkt, size_t pktlen) { struct asr_unpack p; struct asr_dns_header h; struct asr_dns_query q; struct asr_dns_rr rr; int i; union { struct sockaddr sa; struct sockaddr_in sain; struct sockaddr_in6 sain6; } u; char buf[MAXDNAME], *c; _asr_unpack_init(&p, pkt, pktlen); _asr_unpack_header(&p, &h); for (; h.qdcount; h.qdcount--) _asr_unpack_query(&p, &q); for (i = 0; i < h.ancount; i++) { _asr_unpack_rr(&p, &rr); if (rr.rr_type != q.q_type || rr.rr_class != q.q_class) continue; memset(&u, 0, sizeof u); if (rr.rr_type == T_A) { u.sain.sin_len = sizeof u.sain; u.sain.sin_family = AF_INET; u.sain.sin_addr = rr.rr.in_a.addr; u.sain.sin_port = 0; } else if (rr.rr_type == T_AAAA) { u.sain6.sin6_len = sizeof u.sain6; u.sain6.sin6_family = AF_INET6; u.sain6.sin6_addr = rr.rr.in_aaaa.addr6; u.sain6.sin6_port = 0; } else continue; if (as->as.ai.hints.ai_flags & AI_CANONNAME) { _asr_strdname(rr.rr_dname, buf, sizeof buf); buf[strlen(buf) - 1] = '\0'; c = res_hnok(buf) ? buf : as->as.ai.hostname; } else if (as->as.ai.hints.ai_flags & AI_FQDN) c = as->as.ai.fqdn; else c = NULL; if (addrinfo_add(as, &u.sa, c)) return (-1); /* errno set */ } return (0); } static int addrconfig_setup(struct asr_query *as) { struct ifaddrs *ifa, *ifa0; struct if_data *ifa_data; struct sockaddr_in *sinp; struct sockaddr_in6 *sin6p; int rtable, ifa_rtable = -1; if (getifaddrs(&ifa0) == -1) return (-1); rtable = getrtable(); as->as_flags |= ASYNC_NO_INET | ASYNC_NO_INET6; for (ifa = ifa0; ifa != NULL; ifa = ifa->ifa_next) { if (ifa->ifa_addr == NULL) continue; switch (ifa->ifa_addr->sa_family) { case PF_LINK: /* AF_LINK comes before inet / inet6 on an interface */ ifa_data = (struct if_data *)ifa->ifa_data; ifa_rtable = ifa_data->ifi_rdomain; break; case PF_INET: if (ifa_rtable != rtable) continue; sinp = (struct sockaddr_in *)ifa->ifa_addr; if (sinp->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) continue; as->as_flags &= ~ASYNC_NO_INET; break; case PF_INET6: if (ifa_rtable != rtable) continue; sin6p = (struct sockaddr_in6 *)ifa->ifa_addr; if (IN6_IS_ADDR_LOOPBACK(&sin6p->sin6_addr)) continue; if (IN6_IS_ADDR_LINKLOCAL(&sin6p->sin6_addr)) continue; as->as_flags &= ~ASYNC_NO_INET6; break; } } freeifaddrs(ifa0); return (0); }