/* Host name resolution and matching. Copyright (C) 1995, 1996, 1997, 2000, 2001 Free Software Foundation, Inc. This file is part of GNU Wget. GNU Wget is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. GNU Wget is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Wget; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. In addition, as a special exception, the Free Software Foundation gives permission to link the code of its release of Wget with the OpenSSL project's "OpenSSL" library (or with modified versions of it that use the same license as the "OpenSSL" library), and distribute the linked executables. You must obey the GNU General Public License in all respects for all of the code used other than "OpenSSL". If you modify this file, you may extend this exception to your version of the file, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ #include #ifndef WINDOWS #include #endif #include #include #ifdef HAVE_STRING_H # include #else # include #endif #include #include #ifdef WINDOWS # include # define SET_H_ERRNO(err) WSASetLastError (err) #else # include # include # ifndef __BEOS__ # include # endif # include # define SET_H_ERRNO(err) ((void)(h_errno = (err))) #endif /* WINDOWS */ #ifndef NO_ADDRESS #define NO_ADDRESS NO_DATA #endif #ifdef HAVE_SYS_UTSNAME_H # include #endif #include #include "wget.h" #include "utils.h" #include "host.h" #include "url.h" #include "hash.h" #ifndef errno extern int errno; #endif #ifndef h_errno # ifndef __CYGWIN__ extern int h_errno; # endif #endif #ifdef ENABLE_IPV6 int ip_default_family = AF_UNSPEC; #else int ip_default_family = AF_INET; #endif /* Mapping between known hosts and to lists of their addresses. */ static struct hash_table *host_name_addresses_map; /* Lists of addresses. This should eventually be extended to handle IPv6. */ struct address_list { int count; /* number of adrresses */ ip_address *addresses; /* pointer to the string of addresses */ int faulty; /* number of addresses known not to work. */ int from_cache; /* whether this entry was pulled from cache or freshly looked up. */ int refcount; /* reference count; when it drops to 0, the entry is freed. */ }; /* Get the bounds of the address list. */ void address_list_get_bounds (const struct address_list *al, int *start, int *end) { *start = al->faulty; *end = al->count; } /* Return whether this address list entry has been obtained from the cache. */ int address_list_cached_p (const struct address_list *al) { return al->from_cache; } /* Return a pointer to the address at position POS. */ const ip_address * address_list_address_at (const struct address_list *al, int pos) { assert (pos >= al->faulty && pos < al->count); return al->addresses + pos; } /* Check whether two address lists have all their IPs in common. */ int address_list_match_all (const struct address_list *al1, const struct address_list *al2) { #ifdef ENABLE_IPV6 int i; #endif if (al1 == al2) return 1; if (al1->count != al2->count) return 0; /* For the comparison to be complete, we'd need to sort the IP addresses first. But that's not necessary because this is only used as an optimization. */ #ifndef ENABLE_IPV6 /* In the non-IPv6 case, there is only one address type, so we can compare the whole array with memcmp. */ return 0 == memcmp (al1->addresses, al2->addresses, al1->count * sizeof (ip_address)); #else /* ENABLE_IPV6 */ for (i = 0; i < al1->count; ++i) { const ip_address *ip1 = &al1->addresses[i]; const ip_address *ip2 = &al2->addresses[i]; if (ip1->type != ip2->type) return 0; switch (ip1->type) { case IPV4_ADDRESS: if (ADDRESS_IPV4_IN_ADDR (ip1).s_addr != ADDRESS_IPV4_IN_ADDR (ip2).s_addr) return 0; break; case IPV6_ADDRESS: #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID if (ADDRESS_IPV6_SCOPE (ip1) != ADDRESS_IPV6_SCOPE (ip2)) return 0; #endif /* HAVE_SOCKADDR_IN6_SCOPE_ID */ if (!IN6_ARE_ADDR_EQUAL (&ADDRESS_IPV6_IN6_ADDR (ip1), &ADDRESS_IPV6_IN6_ADDR (ip2))) return 0; break; default: abort (); } } return 1; #endif /* ENABLE_IPV6 */ } /* Mark the INDEXth element of AL as faulty, so that the next time this address list is used, the faulty element will be skipped. */ void address_list_set_faulty (struct address_list *al, int index) { /* We assume that the address list is traversed in order, so that a "faulty" attempt is always preceded with all-faulty addresses, and this is how Wget uses it. */ assert (index == al->faulty); ++al->faulty; if (al->faulty >= al->count) /* All addresses have been proven faulty. Since there's not much sense in returning the user an empty address list the next time, we'll rather make them all clean, so that they can be retried anew. */ al->faulty = 0; } #ifdef ENABLE_IPV6 /** * address_list_from_addrinfo * * This function transform an addrinfo links list in and address_list. * * Input: * addrinfo* Linked list of addrinfo * * Output: * address_list* New allocated address_list */ static struct address_list * address_list_from_addrinfo (const struct addrinfo *ai) { struct address_list *al; const struct addrinfo *ptr; int cnt; ip_address *ip; cnt = 0; for (ptr = ai; ptr != NULL ; ptr = ptr->ai_next) if (ptr->ai_family == AF_INET || ptr->ai_family == AF_INET6) ++cnt; if (cnt == 0) return NULL; al = xmalloc (sizeof (struct address_list)); al->addresses = xmalloc (cnt * sizeof (ip_address)); al->count = cnt; al->faulty = 0; al->from_cache = 0; al->refcount = 1; ip = al->addresses; for (ptr = ai; ptr != NULL; ptr = ptr->ai_next) if (ptr->ai_family == AF_INET6) { const struct sockaddr_in6 *sin6 = (const struct sockaddr_in6 *)ptr->ai_addr; ip->type = IPV6_ADDRESS; ADDRESS_IPV6_IN6_ADDR (ip) = sin6->sin6_addr; #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID ADDRESS_IPV6_SCOPE (ip) = sin6->sin6_scope_id; #endif ++ip; } else if (ptr->ai_family == AF_INET) { const struct sockaddr_in *sin = (const struct sockaddr_in *)ptr->ai_addr; ip->type = IPV4_ADDRESS; ADDRESS_IPV4_IN_ADDR (ip) = sin->sin_addr; ++ip; } assert (ip - al->addresses == cnt); return al; } #else /* Create an address_list out of a NULL-terminated vector of addresses, as returned by gethostbyname. */ static struct address_list * address_list_from_vector (char **h_addr_list) { int count, i; struct address_list *al = xmalloc (sizeof (struct address_list)); count = 0; while (h_addr_list[count]) ++count; assert (count > 0); al->count = count; al->faulty = 0; al->addresses = xmalloc (count * sizeof (ip_address)); al->from_cache = 0; al->refcount = 1; for (i = 0; i < count; i++) { ip_address *ip = &al->addresses[i]; ip->type = IPV4_ADDRESS; memcpy (ADDRESS_IPV4_DATA (ip), h_addr_list[i], 4); } return al; } /* Like address_list_from_vector, but initialized with a single address. */ static struct address_list * address_list_from_single (const ip_address *addr) { struct address_list *al = xmalloc (sizeof (struct address_list)); al->count = 1; al->faulty = 0; al->addresses = xmalloc (sizeof (ip_address)); al->from_cache = 0; al->refcount = 1; memcpy (al->addresses, addr, sizeof (ip_address)); return al; } #endif static void address_list_delete (struct address_list *al) { xfree (al->addresses); xfree (al); } void address_list_release (struct address_list *al) { --al->refcount; DEBUGP (("Releasing %p (new refcount %d).\n", al, al->refcount)); if (al->refcount <= 0) { DEBUGP (("Deleting unused %p.\n", al)); address_list_delete (al); } } /* Versions of gethostbyname and getaddrinfo that support timeout. */ #ifndef ENABLE_IPV6 struct ghbnwt_context { const char *host_name; struct hostent *hptr; }; static void gethostbyname_with_timeout_callback (void *arg) { struct ghbnwt_context *ctx = (struct ghbnwt_context *)arg; ctx->hptr = gethostbyname (ctx->host_name); } /* Just like gethostbyname, except it times out after TIMEOUT seconds. In case of timeout, NULL is returned and errno is set to ETIMEDOUT. The function makes sure that when NULL is returned for reasons other than timeout, errno is reset. */ static struct hostent * gethostbyname_with_timeout (const char *host_name, double timeout) { struct ghbnwt_context ctx; ctx.host_name = host_name; if (run_with_timeout (timeout, gethostbyname_with_timeout_callback, &ctx)) { SET_H_ERRNO (HOST_NOT_FOUND); errno = ETIMEDOUT; return NULL; } if (!ctx.hptr) errno = 0; return ctx.hptr; } #else /* ENABLE_IPV6 */ struct gaiwt_context { const char *node; const char *service; const struct addrinfo *hints; struct addrinfo **res; int exit_code; }; static void getaddrinfo_with_timeout_callback (void *arg) { struct gaiwt_context *ctx = (struct gaiwt_context *)arg; ctx->exit_code = getaddrinfo (ctx->node, ctx->service, ctx->hints, ctx->res); } /* Just like getaddrinfo, except it times out after TIMEOUT seconds. In case of timeout, the EAI_SYSTEM error code is returned and errno is set to ETIMEDOUT. */ static int getaddrinfo_with_timeout (const char *node, const char *service, const struct addrinfo *hints, struct addrinfo **res, double timeout) { struct gaiwt_context ctx; ctx.node = node; ctx.service = service; ctx.hints = hints; ctx.res = res; if (run_with_timeout (timeout, getaddrinfo_with_timeout_callback, &ctx)) { errno = ETIMEDOUT; return EAI_SYSTEM; } return ctx.exit_code; } #endif /* ENABLE_IPV6 */ /* Pretty-print ADDR. When compiled without IPv6, this is the same as inet_ntoa. With IPv6, it either prints an IPv6 address or an IPv4 address. */ const char * pretty_print_address (const ip_address *addr) { switch (addr->type) { case IPV4_ADDRESS: return inet_ntoa (ADDRESS_IPV4_IN_ADDR (addr)); #ifdef ENABLE_IPV6 case IPV6_ADDRESS: { static char buf[128]; inet_ntop (AF_INET6, &ADDRESS_IPV6_IN6_ADDR (addr), buf, sizeof (buf)); #if 0 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID { /* append "%SCOPE_ID" for all ?non-global? addresses */ char *p = buf + strlen (buf); *p++ = '%'; number_to_string (p, ADDRESS_IPV6_SCOPE (addr)); } #endif #endif buf[sizeof (buf) - 1] = '\0'; return buf; } #endif } abort (); return NULL; } /* Add host name HOST with the address ADDR_TEXT to the cache. ADDR_LIST is a NULL-terminated list of addresses, as in struct hostent. */ static void cache_host_lookup (const char *host, struct address_list *al) { if (!host_name_addresses_map) host_name_addresses_map = make_nocase_string_hash_table (0); ++al->refcount; hash_table_put (host_name_addresses_map, xstrdup_lower (host), al); #ifdef ENABLE_DEBUG if (opt.debug) { int i; debug_logprintf ("Caching %s =>", host); for (i = 0; i < al->count; i++) debug_logprintf (" %s", pretty_print_address (al->addresses + i)); debug_logprintf ("\n"); } #endif } void forget_host_lookup (const char *host) { struct address_list *al = hash_table_get (host_name_addresses_map, host); if (al) { address_list_release (al); hash_table_remove (host_name_addresses_map, host); } } struct address_list * lookup_host (const char *host, int flags) { struct address_list *al = NULL; #ifdef ENABLE_IPV6 int err, family; struct addrinfo hints, *res; /* Is this necessary? Should this function be changed to accept a FAMILY argument? */ if (flags & LH_IPV4_ONLY) family = AF_INET; else if (flags & LH_IPV6_ONLY) family = AF_INET6; else family = ip_default_family; #endif /* First, try to check whether the address is already a numeric address, in which case we don't need to cache it or bother with setting up timeouts. Plus, if memory serves me right, Ultrix's gethostbyname can't handle numeric addresses (!). Where getaddrinfo is available, we do it using the AI_NUMERICHOST flag. Without IPv6, we use inet_addr succeeds. */ #ifdef ENABLE_IPV6 memset (&hints, 0, sizeof (hints)); hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_NUMERICHOST; if (flags & LH_PASSIVE) hints.ai_flags = AI_PASSIVE; /* no need to call getaddrinfo_with_timeout here, as we're not * relying on the DNS, but we're only doing an address translation * from presentation (ASCII) to network format */ err = getaddrinfo (host, NULL, &hints, &res); if (err == 0 && res != NULL) { al = address_list_from_addrinfo (res); freeaddrinfo (res); return al; } #else { uint32_t addr_ipv4 = (uint32_t)inet_addr (host); if (addr_ipv4 != (uint32_t) -1) { /* The return value of inet_addr is in network byte order, so we can just copy it to IP. */ ip_address ip; ip.type = IPV4_ADDRESS; memcpy (ADDRESS_IPV4_DATA (&ip), &addr_ipv4, 4); return address_list_from_single (&ip); } } #endif /* Then, try to find the host in the cache. */ if (host_name_addresses_map) { al = hash_table_get (host_name_addresses_map, host); if (al) { DEBUGP (("Found %s in host_name_addresses_map (%p)\n", host, al)); ++al->refcount; al->from_cache = 1; return al; } } if (!(flags & LH_SILENT)) logprintf (LOG_VERBOSE, _("Resolving %s... "), host); /* Host name lookup goes on below. */ #ifdef ENABLE_IPV6 { memset (&hints, 0, sizeof (hints)); hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; if (flags & LH_PASSIVE) hints.ai_flags = AI_PASSIVE; err = getaddrinfo_with_timeout (host, NULL, &hints, &res, opt.dns_timeout); if (err != 0 || res == NULL) { if (!(flags & LH_SILENT)) logprintf (LOG_VERBOSE, _("failed: %s.\n"), err != EAI_SYSTEM ? gai_strerror (err) : strerror (errno)); return NULL; } al = address_list_from_addrinfo (res); freeaddrinfo (res); } #else { struct hostent *hptr = gethostbyname_with_timeout (host, opt.dns_timeout); if (!hptr) { if (!(flags & LH_SILENT)) { if (errno != ETIMEDOUT) logprintf (LOG_VERBOSE, _("failed: %s.\n"), herrmsg (h_errno)); else logputs (LOG_VERBOSE, _("failed: timed out.\n")); } return NULL; } assert (hptr->h_length == 4); /* Do all systems have h_addr_list, or is it a newer thing? If the latter, use address_list_from_single. */ al = address_list_from_vector (hptr->h_addr_list); } #endif /* Print the addresses determined by DNS lookup, but no more than three. */ if (!(flags & LH_SILENT)) { int i; int printmax = al->count <= 3 ? al->count : 3; for (i = 0; i < printmax; i++) { logprintf (LOG_VERBOSE, "%s", pretty_print_address (al->addresses + i)); if (i < printmax - 1) logputs (LOG_VERBOSE, ", "); } if (printmax != al->count) logputs (LOG_VERBOSE, ", ..."); logputs (LOG_VERBOSE, "\n"); } /* Cache the lookup information. */ if (opt.dns_cache) cache_host_lookup (host, al); return al; } /* Determine whether a URL is acceptable to be followed, according to a list of domains to accept. */ int accept_domain (struct url *u) { assert (u->host != NULL); if (opt.domains) { if (!sufmatch ((const char **)opt.domains, u->host)) return 0; } if (opt.exclude_domains) { if (sufmatch ((const char **)opt.exclude_domains, u->host)) return 0; } return 1; } /* Check whether WHAT is matched in LIST, each element of LIST being a pattern to match WHAT against, using backward matching (see match_backwards() in utils.c). If an element of LIST matched, 1 is returned, 0 otherwise. */ int sufmatch (const char **list, const char *what) { int i, j, k, lw; lw = strlen (what); for (i = 0; list[i]; i++) { for (j = strlen (list[i]), k = lw; j >= 0 && k >= 0; j--, k--) if (TOLOWER (list[i][j]) != TOLOWER (what[k])) break; /* The domain must be first to reach to beginning. */ if (j == -1) return 1; } return 0; } /* Print error messages for host errors. */ char * herrmsg (int error) { /* Can't use switch since some constants are equal (at least on my system), and the compiler signals "duplicate case value". */ if (error == HOST_NOT_FOUND || error == NO_RECOVERY || error == NO_DATA || error == NO_ADDRESS || error == TRY_AGAIN) return _("Host not found"); else return _("Unknown error"); } static int host_cleanup_mapper (void *key, void *value, void *arg_ignored) { struct address_list *al; xfree (key); /* host */ al = (struct address_list *)value; assert (al->refcount == 1); address_list_delete (al); return 0; } void host_cleanup (void) { if (host_name_addresses_map) { hash_table_map (host_name_addresses_map, host_cleanup_mapper, NULL); hash_table_destroy (host_name_addresses_map); host_name_addresses_map = NULL; } }