1 /* Host name resolution and matching.
2 Copyright (C) 1995, 1996, 1997, 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GNU Wget.
6 GNU Wget is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 GNU Wget is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with Wget; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 In addition, as a special exception, the Free Software Foundation
21 gives permission to link the code of its release of Wget with the
22 OpenSSL project's "OpenSSL" library (or with modified versions of it
23 that use the same license as the "OpenSSL" library), and distribute
24 the linked executables. You must obey the GNU General Public License
25 in all respects for all of the code used other than "OpenSSL". If you
26 modify this file, you may extend this exception to your version of the
27 file, but you are not obligated to do so. If you do not wish to do
28 so, delete this exception statement from your version. */
42 # include <sys/socket.h>
43 # include <netinet/in.h>
45 # include <arpa/inet.h>
48 # define SET_H_ERRNO(err) ((void)(h_errno = (err)))
50 # define SET_H_ERRNO(err) WSASetLastError (err)
60 #include "connect.h" /* for socket_has_inet6 */
63 # define NO_ADDRESS NO_DATA
66 /* Lists of IP addresses that result from running DNS queries. See
67 lookup_host for details. */
70 int count; /* number of adrresses */
71 ip_address *addresses; /* pointer to the string of addresses */
73 int faulty; /* number of addresses known not to work. */
74 int connected; /* whether we were able to connect to
75 one of the addresses in the list,
78 int refcount; /* reference count; when it drops to
79 0, the entry is freed. */
82 /* Get the bounds of the address list. */
85 address_list_get_bounds (const struct address_list *al, int *start, int *end)
91 /* Return a pointer to the address at position POS. */
94 address_list_address_at (const struct address_list *al, int pos)
96 assert (pos >= al->faulty && pos < al->count);
97 return al->addresses + pos;
100 /* Return non-zero if AL contains IP, zero otherwise. */
103 address_list_contains (const struct address_list *al, const ip_address *ip)
109 for (i = 0; i < al->count; i++)
111 ip_address *cur = al->addresses + i;
112 if (cur->type == IPV4_ADDRESS
113 && (ADDRESS_IPV4_IN_ADDR (cur).s_addr
115 ADDRESS_IPV4_IN_ADDR (ip).s_addr))
121 for (i = 0; i < al->count; i++)
123 ip_address *cur = al->addresses + i;
124 if (cur->type == IPV6_ADDRESS
125 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
126 && ADDRESS_IPV6_SCOPE (cur) == ADDRESS_IPV6_SCOPE (ip)
128 && IN6_ARE_ADDR_EQUAL (&ADDRESS_IPV6_IN6_ADDR (cur),
129 &ADDRESS_IPV6_IN6_ADDR (ip)))
133 #endif /* ENABLE_IPV6 */
139 /* Mark the INDEXth element of AL as faulty, so that the next time
140 this address list is used, the faulty element will be skipped. */
143 address_list_set_faulty (struct address_list *al, int index)
145 /* We assume that the address list is traversed in order, so that a
146 "faulty" attempt is always preceded with all-faulty addresses,
147 and this is how Wget uses it. */
148 assert (index == al->faulty);
151 if (al->faulty >= al->count)
152 /* All addresses have been proven faulty. Since there's not much
153 sense in returning the user an empty address list the next
154 time, we'll rather make them all clean, so that they can be
159 /* Set the "connected" flag to true. This flag used by connect.c to
160 see if the host perhaps needs to be resolved again. */
163 address_list_set_connected (struct address_list *al)
168 /* Return the value of the "connected" flag. */
171 address_list_connected_p (const struct address_list *al)
173 return al->connected;
178 /* Create an address_list from the addresses in the given struct
181 static struct address_list *
182 address_list_from_addrinfo (const struct addrinfo *ai)
184 struct address_list *al;
185 const struct addrinfo *ptr;
190 for (ptr = ai; ptr != NULL ; ptr = ptr->ai_next)
191 if (ptr->ai_family == AF_INET || ptr->ai_family == AF_INET6)
196 al = xnew0 (struct address_list);
197 al->addresses = xnew_array (ip_address, cnt);
202 for (ptr = ai; ptr != NULL; ptr = ptr->ai_next)
203 if (ptr->ai_family == AF_INET6)
205 const struct sockaddr_in6 *sin6 =
206 (const struct sockaddr_in6 *)ptr->ai_addr;
207 ip->type = IPV6_ADDRESS;
208 ADDRESS_IPV6_IN6_ADDR (ip) = sin6->sin6_addr;
209 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
210 ADDRESS_IPV6_SCOPE (ip) = sin6->sin6_scope_id;
214 else if (ptr->ai_family == AF_INET)
216 const struct sockaddr_in *sin =
217 (const struct sockaddr_in *)ptr->ai_addr;
218 ip->type = IPV4_ADDRESS;
219 ADDRESS_IPV4_IN_ADDR (ip) = sin->sin_addr;
222 assert (ip - al->addresses == cnt);
226 #define IS_IPV4(addr) (((const ip_address *) addr)->type == IPV4_ADDRESS)
228 /* Compare two IP addresses by type, giving preference to the IPv4
229 address (sorting it first). In other words, return -1 if ADDR1 is
230 IPv4 and ADDR2 is IPv6, +1 if ADDR1 is IPv6 and ADDR2 is IPv4, and
233 This is intended to be used as the comparator arg to a qsort-like
234 sorting function, which is why it accepts generic pointers. */
237 cmp_prefer_ipv4 (const void *addr1, const void *addr2)
239 return !IS_IPV4 (addr1) - !IS_IPV4 (addr2);
242 #define IS_IPV6(addr) (((const ip_address *) addr)->type == IPV6_ADDRESS)
244 /* Like the above, but give preference to the IPv6 address. */
247 cmp_prefer_ipv6 (const void *addr1, const void *addr2)
249 return !IS_IPV6 (addr1) - !IS_IPV6 (addr2);
252 #else /* not ENABLE_IPV6 */
254 /* Create an address_list from a NULL-terminated vector of IPv4
255 addresses. This kind of vector is returned by gethostbyname. */
257 static struct address_list *
258 address_list_from_ipv4_addresses (char **vec)
261 struct address_list *al = xnew0 (struct address_list);
268 al->addresses = xnew_array (ip_address, count);
272 for (i = 0; i < count; i++)
274 ip_address *ip = &al->addresses[i];
275 ip->type = IPV4_ADDRESS;
276 memcpy (ADDRESS_IPV4_DATA (ip), vec[i], 4);
282 #endif /* not ENABLE_IPV6 */
285 address_list_delete (struct address_list *al)
287 xfree (al->addresses);
291 /* Mark the address list as being no longer in use. This will reduce
292 its reference count which will cause the list to be freed when the
296 address_list_release (struct address_list *al)
299 DEBUGP (("Releasing 0x%0*lx (new refcount %d).\n", PTR_FORMAT (al),
301 if (al->refcount <= 0)
303 DEBUGP (("Deleting unused 0x%0*lx.\n", PTR_FORMAT (al)));
304 address_list_delete (al);
308 /* Versions of gethostbyname and getaddrinfo that support timeout. */
312 struct ghbnwt_context {
313 const char *host_name;
314 struct hostent *hptr;
318 gethostbyname_with_timeout_callback (void *arg)
320 struct ghbnwt_context *ctx = (struct ghbnwt_context *)arg;
321 ctx->hptr = gethostbyname (ctx->host_name);
324 /* Just like gethostbyname, except it times out after TIMEOUT seconds.
325 In case of timeout, NULL is returned and errno is set to ETIMEDOUT.
326 The function makes sure that when NULL is returned for reasons
327 other than timeout, errno is reset. */
329 static struct hostent *
330 gethostbyname_with_timeout (const char *host_name, double timeout)
332 struct ghbnwt_context ctx;
333 ctx.host_name = host_name;
334 if (run_with_timeout (timeout, gethostbyname_with_timeout_callback, &ctx))
336 SET_H_ERRNO (HOST_NOT_FOUND);
345 /* Print error messages for host errors. */
347 host_errstr (int error)
349 /* Can't use switch since some of these constants can be equal,
350 which makes the compiler complain about duplicate case
352 if (error == HOST_NOT_FOUND
353 || error == NO_RECOVERY
355 || error == NO_ADDRESS)
356 return _("Unknown host");
357 else if (error == TRY_AGAIN)
358 /* Message modeled after what gai_strerror returns in similar
360 return _("Temporary failure in name resolution");
362 return _("Unknown error");
365 #else /* ENABLE_IPV6 */
367 struct gaiwt_context {
370 const struct addrinfo *hints;
371 struct addrinfo **res;
376 getaddrinfo_with_timeout_callback (void *arg)
378 struct gaiwt_context *ctx = (struct gaiwt_context *)arg;
379 ctx->exit_code = getaddrinfo (ctx->node, ctx->service, ctx->hints, ctx->res);
382 /* Just like getaddrinfo, except it times out after TIMEOUT seconds.
383 In case of timeout, the EAI_SYSTEM error code is returned and errno
384 is set to ETIMEDOUT. */
387 getaddrinfo_with_timeout (const char *node, const char *service,
388 const struct addrinfo *hints, struct addrinfo **res,
391 struct gaiwt_context ctx;
393 ctx.service = service;
397 if (run_with_timeout (timeout, getaddrinfo_with_timeout_callback, &ctx))
402 return ctx.exit_code;
405 #endif /* ENABLE_IPV6 */
407 /* Pretty-print ADDR. When compiled without IPv6, this is the same as
408 inet_ntoa. With IPv6, it either prints an IPv6 address or an IPv4
412 pretty_print_address (const ip_address *addr)
417 return inet_ntoa (ADDRESS_IPV4_IN_ADDR (addr));
421 static char buf[128];
422 inet_ntop (AF_INET6, &ADDRESS_IPV6_IN6_ADDR (addr), buf, sizeof (buf));
424 #ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
426 /* append "%SCOPE_ID" for all ?non-global? addresses */
427 char *p = buf + strlen (buf);
429 number_to_string (p, ADDRESS_IPV6_SCOPE (addr));
433 buf[sizeof (buf) - 1] = '\0';
441 /* The following two functions were adapted from glibc. */
444 is_valid_ipv4_address (const char *str, const char *end)
454 if (ch >= '0' && ch <= '9')
456 val = val * 10 + (ch - '0');
467 else if (ch == '.' && saw_digit == 1)
484 is_valid_ipv6_address (const char *str, const char *end)
486 /* Use lower-case for these to avoid clash with system headers. */
505 /* Leading :: requires some special handling. */
509 if (str == end || *str != ':')
521 /* if ch is a number, add it to val. */
525 val |= XDIGIT_TO_NUM (ch);
532 /* if ch is a colon ... */
545 if (tp > ns_in6addrsz - ns_int16sz)
553 /* if ch is a dot ... */
554 if (ch == '.' && (tp <= ns_in6addrsz - ns_inaddrsz)
555 && is_valid_ipv4_address (curtok, end) == 1)
567 if (tp > ns_in6addrsz - ns_int16sz)
574 if (tp == ns_in6addrsz)
579 if (tp != ns_in6addrsz)
585 /* Simple host cache, used by lookup_host to speed up resolving. The
586 cache doesn't handle TTL because Wget is a fairly short-lived
587 application. Refreshing is attempted when connect fails, though --
588 see connect_to_host. */
590 /* Mapping between known hosts and to lists of their addresses. */
591 static struct hash_table *host_name_addresses_map;
594 /* Return the host's resolved addresses from the cache, if
597 static struct address_list *
598 cache_query (const char *host)
600 struct address_list *al;
601 if (!host_name_addresses_map)
603 al = hash_table_get (host_name_addresses_map, host);
606 DEBUGP (("Found %s in host_name_addresses_map (%p)\n", host, al));
613 /* Cache the DNS lookup of HOST. Subsequent invocations of
614 lookup_host will return the cached value. */
617 cache_store (const char *host, struct address_list *al)
619 if (!host_name_addresses_map)
620 host_name_addresses_map = make_nocase_string_hash_table (0);
623 hash_table_put (host_name_addresses_map, xstrdup_lower (host), al);
629 debug_logprintf ("Caching %s =>", host);
630 for (i = 0; i < al->count; i++)
631 debug_logprintf (" %s", pretty_print_address (al->addresses + i));
632 debug_logprintf ("\n");
637 /* Remove HOST from the DNS cache. Does nothing is HOST is not in
641 cache_remove (const char *host)
643 struct address_list *al;
644 if (!host_name_addresses_map)
646 al = hash_table_get (host_name_addresses_map, host);
649 address_list_release (al);
650 hash_table_remove (host_name_addresses_map, host);
654 /* Look up HOST in DNS and return a list of IP addresses.
656 This function caches its result so that, if the same host is passed
657 the second time, the addresses are returned without DNS lookup.
658 (Use LH_REFRESH to force lookup, or set opt.dns_cache to 0 to
659 globally disable caching.)
661 The order of the returned addresses is affected by the setting of
662 opt.prefer_family: if it is set to prefer_ipv4, IPv4 addresses are
663 placed at the beginning; if it is prefer_ipv6, IPv6 ones are placed
664 at the beginning; otherwise, the order is left intact. The
665 relative order of addresses with the same family is left
666 undisturbed in either case.
668 FLAGS can be a combination of:
669 LH_SILENT - don't print the "resolving ... done" messages.
670 LH_BIND - resolve addresses for use with bind, which under
671 IPv6 means to use AI_PASSIVE flag to getaddrinfo.
672 Passive lookups are not cached under IPv6.
673 LH_REFRESH - if HOST is cached, remove the entry from the cache
674 and resolve it anew. */
676 struct address_list *
677 lookup_host (const char *host, int flags)
679 struct address_list *al;
680 int silent = flags & LH_SILENT;
682 int numeric_address = 0;
683 double timeout = opt.dns_timeout;
686 /* If we're not using getaddrinfo, first check if HOST specifies a
687 numeric IPv4 address. Some implementations of gethostbyname
688 (e.g. the Ultrix one and possibly Winsock) don't accept
689 dotted-decimal IPv4 addresses. */
691 uint32_t addr_ipv4 = (uint32_t)inet_addr (host);
692 if (addr_ipv4 != (uint32_t) -1)
694 /* No need to cache host->addr relation, just return the
697 vec[0] = (char *)&addr_ipv4;
699 return address_list_from_ipv4_addresses (vec);
702 #else /* ENABLE_IPV6 */
703 /* If we're using getaddrinfo, at least check whether the address is
704 already numeric, in which case there is no need to print the
705 "Resolving..." output. (This comes at no additional cost since
706 the is_valid_ipv*_address are already required for
709 const char *end = host + strlen (host);
710 if (is_valid_ipv4_address (host, end) || is_valid_ipv6_address (host, end))
715 /* Cache is normally on, but can be turned off with --no-dns-cache.
716 Don't cache passive lookups under IPv6. */
717 use_cache = opt.dns_cache;
719 if ((flags & LH_BIND) || numeric_address)
723 /* Try to find the host in the cache so we don't need to talk to the
724 resolver. If LH_REFRESH is requested, remove HOST from the cache
728 if (!(flags & LH_REFRESH))
730 al = cache_query (host);
738 /* No luck with the cache; resolve HOST. */
740 if (!silent && !numeric_address)
741 logprintf (LOG_VERBOSE, _("Resolving %s... "), escnonprint (host));
746 struct addrinfo hints, *res;
749 hints.ai_socktype = SOCK_STREAM;
751 hints.ai_family = AF_INET;
752 else if (opt.ipv6_only)
753 hints.ai_family = AF_INET6;
755 /* We tried using AI_ADDRCONFIG, but removed it because: it
756 misinterprets IPv6 loopbacks, it is broken on AIX 5.1, and
757 it's unneeded since we sort the addresses anyway. */
758 hints.ai_family = AF_UNSPEC;
761 hints.ai_flags |= AI_PASSIVE;
763 #ifdef AI_NUMERICHOST
766 /* Where available, the AI_NUMERICHOST hint can prevent costly
767 access to DNS servers. */
768 hints.ai_flags |= AI_NUMERICHOST;
769 timeout = 0; /* no timeout needed when "resolving"
770 numeric hosts -- avoid setting up
771 signal handlers and such. */
775 err = getaddrinfo_with_timeout (host, NULL, &hints, &res, timeout);
776 if (err != 0 || res == NULL)
779 logprintf (LOG_VERBOSE, _("failed: %s.\n"),
780 err != EAI_SYSTEM ? gai_strerror (err) : strerror (errno));
783 al = address_list_from_addrinfo (res);
787 logprintf (LOG_VERBOSE,
788 _("failed: No IPv4/IPv6 addresses for host.\n"));
792 /* Reorder addresses so that IPv4 ones (or IPv6 ones, as per
793 --prefer-family) come first. Sorting is stable so the order of
794 the addresses with the same family is undisturbed. */
795 if (al->count > 1 && opt.prefer_family != prefer_none)
796 stable_sort (al->addresses, al->count, sizeof (ip_address),
797 opt.prefer_family == prefer_ipv4
798 ? cmp_prefer_ipv4 : cmp_prefer_ipv6);
800 #else /* not ENABLE_IPV6 */
802 struct hostent *hptr = gethostbyname_with_timeout (host, timeout);
807 if (errno != ETIMEDOUT)
808 logprintf (LOG_VERBOSE, _("failed: %s.\n"),
809 host_errstr (h_errno));
811 logputs (LOG_VERBOSE, _("failed: timed out.\n"));
815 /* Do older systems have h_addr_list? */
816 al = address_list_from_ipv4_addresses (hptr->h_addr_list);
818 #endif /* not ENABLE_IPV6 */
820 /* Print the addresses determined by DNS lookup, but no more than
822 if (!silent && !numeric_address)
825 int printmax = al->count <= 3 ? al->count : 3;
826 for (i = 0; i < printmax; i++)
828 logprintf (LOG_VERBOSE, "%s",
829 pretty_print_address (al->addresses + i));
830 if (i < printmax - 1)
831 logputs (LOG_VERBOSE, ", ");
833 if (printmax != al->count)
834 logputs (LOG_VERBOSE, ", ...");
835 logputs (LOG_VERBOSE, "\n");
838 /* Cache the lookup information. */
840 cache_store (host, al);
845 /* Determine whether a URL is acceptable to be followed, according to
846 a list of domains to accept. */
848 accept_domain (struct url *u)
850 assert (u->host != NULL);
853 if (!sufmatch ((const char **)opt.domains, u->host))
856 if (opt.exclude_domains)
858 if (sufmatch ((const char **)opt.exclude_domains, u->host))
864 /* Check whether WHAT is matched in LIST, each element of LIST being a
865 pattern to match WHAT against, using backward matching (see
866 match_backwards() in utils.c).
868 If an element of LIST matched, 1 is returned, 0 otherwise. */
870 sufmatch (const char **list, const char *what)
875 for (i = 0; list[i]; i++)
877 for (j = strlen (list[i]), k = lw; j >= 0 && k >= 0; j--, k--)
878 if (TOLOWER (list[i][j]) != TOLOWER (what[k]))
880 /* The domain must be first to reach to beginning. */
888 host_cleanup_mapper (void *key, void *value, void *arg_ignored)
890 struct address_list *al;
892 xfree (key); /* host */
894 al = (struct address_list *)value;
895 assert (al->refcount == 1);
896 address_list_delete (al);
904 if (host_name_addresses_map)
906 hash_table_map (host_name_addresses_map, host_cleanup_mapper, NULL);
907 hash_table_destroy (host_name_addresses_map);
908 host_name_addresses_map = NULL;