-/* Dealing with host names.
- Copyright (C) 1995, 1996, 1997, 2000 Free Software Foundation, Inc.
+/* 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.
+ (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
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. */
+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 <config.h>
+#ifndef WINDOWS
+#include <netdb.h>
+#endif
+
#include <stdio.h>
#include <stdlib.h>
#ifdef HAVE_STRING_H
#ifdef WINDOWS
# include <winsock.h>
+# define SET_H_ERRNO(err) WSASetLastError (err)
#else
# include <sys/socket.h>
# include <netinet/in.h>
-#ifndef __BEOS__
-# include <arpa/inet.h>
-#endif
+# ifndef __BEOS__
+# endif
# include <netdb.h>
+# define SET_H_ERRNO(err) ((void)(h_errno = (err)))
#endif /* WINDOWS */
#ifndef NO_ADDRESS
-#define NO_ADDRESS NO_DATA
+# define NO_ADDRESS NO_DATA
#endif
-#ifdef HAVE_SYS_UTSNAME_H
-# include <sys/utsname.h>
-#endif
#include <errno.h>
#include "wget.h"
#include "host.h"
#include "url.h"
#include "hash.h"
+#include "connect.h" /* for socket_has_inet6 */
#ifndef errno
extern int errno;
#endif
-#define IP4_ADDRESS_LENGTH 4
-
-/* Mapping between known hosts and to lists of their addresses. */
+#ifndef h_errno
+# ifndef __CYGWIN__
+extern int h_errno;
+# endif
+#endif
-struct hash_table *host_name_addresses_map;
-\f
-/* Lists of addresses. This should eventually be extended to handle
- IPv6. */
+/* Lists of IP addresses that result from running DNS queries. See
+ lookup_host for details. */
struct address_list {
int count; /* number of adrresses */
- unsigned char *buffer; /* buffer which holds all of them. */
+ ip_address *addresses; /* pointer to the string of addresses */
- int faulty; /* number of addresses known not to
- work. */
- int refcount; /* so we know whether to free it or
- not. */
-};
+ int faulty; /* number of addresses known not to work. */
+ int connected; /* whether we were able to connect to
+ one of the addresses in the list,
+ at least once. */
-#define ADDR_LOCATION(al, index) ((al)->buffer + index * IP4_ADDRESS_LENGTH)
+ 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 (struct address_list *al, int *start, int *end)
+address_list_get_bounds (const struct address_list *al, int *start, int *end)
{
*start = al->faulty;
*end = al->count;
}
-/* Copy address number INDEX to IP_STORE. */
+/* Return a pointer to the address at position POS. */
-void
-address_list_copy_one (struct address_list *al, int index,
- unsigned char *ip_store)
+const ip_address *
+address_list_address_at (const struct address_list *al, int pos)
{
- assert (index >= al->faulty && index < al->count);
- memcpy (ip_store, ADDR_LOCATION (al, index), IP4_ADDRESS_LENGTH);
+ assert (pos >= al->faulty && pos < al->count);
+ return al->addresses + pos;
}
-/* Check whether two address lists have all their IPs in common. */
+/* Return non-zero if AL contains IP, zero otherwise. */
int
-address_list_match_all (struct address_list *al1, struct address_list *al2)
+address_list_contains (const struct address_list *al, const ip_address *ip)
{
- if (al1 == al2)
- return 1;
- if (al1->count != al2->count)
- return 0;
- return 0 == memcmp (al1->buffer, al2->buffer,
- al1->count * IP4_ADDRESS_LENGTH);
+ int i;
+ switch (ip->type)
+ {
+ case IPV4_ADDRESS:
+ for (i = 0; i < al->count; i++)
+ {
+ ip_address *cur = al->addresses + i;
+ if (cur->type == IPV4_ADDRESS
+ && (ADDRESS_IPV4_IN_ADDR (cur).s_addr
+ ==
+ ADDRESS_IPV4_IN_ADDR (ip).s_addr))
+ return 1;
+ }
+ return 0;
+#ifdef ENABLE_IPV6
+ case IPV6_ADDRESS:
+ for (i = 0; i < al->count; i++)
+ {
+ ip_address *cur = al->addresses + i;
+ if (cur->type == IPV6_ADDRESS
+#ifdef HAVE_SOCKADDR_IN6_SCOPE_ID
+ && ADDRESS_IPV6_SCOPE (cur) == ADDRESS_IPV6_SCOPE (ip)
+#endif
+ && IN6_ARE_ADDR_EQUAL (&ADDRESS_IPV6_IN6_ADDR (cur),
+ &ADDRESS_IPV6_IN6_ADDR (ip)))
+ return 1;
+ }
+ return 0;
+#endif /* ENABLE_IPV6 */
+ default:
+ abort ();
+ return 0;
+ }
}
/* Mark the INDEXth element of AL as faulty, so that the next time
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
al->faulty = 0;
}
-/* Create an address_list out of a NULL-terminated list of addresses,
- as returned by gethostbyname. */
+/* Set the "connected" flag to true. This flag used by connect.c to
+ see if the host perhaps needs to be resolved again. */
+
+void
+address_list_set_connected (struct address_list *al)
+{
+ al->connected = 1;
+}
+
+/* Return the value of the "connected" flag. */
+
+int
+address_list_connected_p (const struct address_list *al)
+{
+ return al->connected;
+}
+
+#ifdef ENABLE_IPV6
+
+/* Create an address_list from the addresses in the given struct
+ addrinfo. */
static struct address_list *
-address_list_new (char **h_addr_list)
+address_list_from_addrinfo (const struct addrinfo *ai)
{
- int count = 0, i;
+ 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 = xnew0 (struct address_list);
+ al->addresses = xnew_array (ip_address, cnt);
+ al->count = cnt;
+ 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 /* not ENABLE_IPV6 */
- struct address_list *al = xmalloc (sizeof (struct address_list));
+/* Create an address_list from a NULL-terminated vector of IPv4
+ addresses. This kind of vector is returned by gethostbyname. */
- while (h_addr_list[count])
+static struct address_list *
+address_list_from_ipv4_addresses (char **vec)
+{
+ int count, i;
+ struct address_list *al = xnew0 (struct address_list);
+
+ count = 0;
+ while (vec[count])
++count;
assert (count > 0);
- al->count = count;
- al->faulty = 0;
- al->buffer = xmalloc (count * IP4_ADDRESS_LENGTH);
- al->refcount = 1;
+
+ al->addresses = xnew_array (ip_address, count);
+ al->count = count;
+ al->refcount = 1;
for (i = 0; i < count; i++)
- memcpy (ADDR_LOCATION (al, i), h_addr_list[i], IP4_ADDRESS_LENGTH);
+ {
+ ip_address *ip = &al->addresses[i];
+ ip->type = IPV4_ADDRESS;
+ memcpy (ADDRESS_IPV4_DATA (ip), vec[i], 4);
+ }
return al;
}
+#endif /* not ENABLE_IPV6 */
+
static void
address_list_delete (struct address_list *al)
{
- xfree (al->buffer);
+ xfree (al->addresses);
xfree (al);
}
+/* Mark the address list as being no longer in use. This will reduce
+ its reference count which will cause the list to be freed when the
+ count reaches 0. */
+
void
address_list_release (struct address_list *al)
{
}
}
\f
-/* The same as inet_ntoa, but without the need for a cast, or for
- #including the netinet stuff. */
+/* 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;
+}
+
+/* Print error messages for host errors. */
+static char *
+host_errstr (int error)
+{
+ /* Can't use switch since some of these constants can be equal,
+ which makes the compiler complain about duplicate case
+ values. */
+ if (error == HOST_NOT_FOUND
+ || error == NO_RECOVERY
+ || error == NO_DATA
+ || error == NO_ADDRESS)
+ return _("Unknown host");
+ else if (error == TRY_AGAIN)
+ /* Message modeled after what gai_strerror returns in similar
+ circumstances. */
+ return _("Temporary failure in name resolution");
+ else
+ return _("Unknown error");
+}
+
+#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 */
+\f
+/* 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. */
-char *
-pretty_print_address (const unsigned char *addr)
+const char *
+pretty_print_address (const ip_address *addr)
{
- return inet_ntoa (*(struct in_addr *)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;
}
+\f
+/* Simple host cache, used by lookup_host to speed up resolving. The
+ cache doesn't handle TTL because Wget is a fairly short-lived
+ application. Refreshing is attempted when connect fails, though --
+ see connect_to_host. */
-/* 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. */
+/* Mapping between known hosts and to lists of their addresses. */
+static struct hash_table *host_name_addresses_map;
+
+
+/* Return the host's resolved addresses from the cache, if
+ available. */
+
+static struct address_list *
+cache_query (const char *host)
+{
+ struct address_list *al;
+ if (!host_name_addresses_map)
+ return NULL;
+ 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;
+ return al;
+ }
+ return NULL;
+}
+
+/* Cache the DNS lookup of HOST. Subsequent invocations of
+ lookup_host will return the cached value. */
static void
-cache_host_lookup (const char *host, struct address_list *al)
+cache_store (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 DEBUG
+#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 (ADDR_LOCATION (al, i)));
+ debug_logprintf (" %s", pretty_print_address (al->addresses + i));
debug_logprintf ("\n");
}
#endif
}
-struct address_list *
-lookup_host (const char *host, int silent)
-{
- struct address_list *al = NULL;
- unsigned long addr;
- struct hostent *hptr;
+/* Remove HOST from the DNS cache. Does nothing is HOST is not in
+ the cache. */
- /* If the address is of the form d.d.d.d, no further lookup is
- needed. */
- addr = (unsigned long)inet_addr (host);
- if ((int)addr != -1)
+static void
+cache_remove (const char *host)
+{
+ struct address_list *al;
+ if (!host_name_addresses_map)
+ return;
+ al = hash_table_get (host_name_addresses_map, host);
+ if (al)
{
- unsigned char tmpstore[IP4_ADDRESS_LENGTH];
- char *lst[] = { tmpstore, NULL };
-
- /* ADDR is defined to be in network byte order, which is what
- this returns, so we can just copy it to STORE_IP. However,
- on big endian 64-bit architectures the value will be stored
- in the *last*, not first four bytes. OFFSET makes sure that
- we copy the correct four bytes. */
- int offset;
-#ifdef WORDS_BIGENDIAN
- offset = sizeof (unsigned long) - IP4_ADDRESS_LENGTH;
-#else
- offset = 0;
-#endif
- memcpy (tmpstore, (char *)&addr + offset, IP4_ADDRESS_LENGTH);
- return address_list_new (lst);
+ address_list_release (al);
+ hash_table_remove (host_name_addresses_map, host);
}
+}
+\f
+/* Look up HOST in DNS and return a list of IP addresses. The
+ addresses in the list are in the same order in which
+ gethostbyname/getaddrinfo returned them.
+
+ This function caches its result so that, if the same host is passed
+ the second time, the addresses are returned without DNS lookup.
+ (Use LH_REFRESH to force lookup, or set opt.dns_cache to 0 to
+ globally disable caching.)
+
+ FLAGS can be a combination of:
+ LH_SILENT - don't print the "resolving ... done" messages.
+ LH_BIND - resolve addresses for use with bind, which under
+ IPv6 means to use AI_PASSIVE flag to getaddrinfo.
+ Passive lookups are not cached under IPv6.
+ LH_REFRESH - if HOST is cached, remove the entry from the cache
+ and resolve it anew. */
- /* By now we know that the host name we got is not of the form
- d.d.d.d. Try to find it in our cache of host names. */
- if (host_name_addresses_map)
- al = hash_table_get (host_name_addresses_map, host);
+struct address_list *
+lookup_host (const char *host, int flags)
+{
+ struct address_list *al;
+ int silent = flags & LH_SILENT;
+ int use_cache;
+
+#ifndef ENABLE_IPV6
+ /* If we're not using getaddrinfo, first check if HOST specifies a
+ numeric IPv4 address. gethostbyname is not required to accept
+ dotted-decimal IPv4 addresses, and some implementations (e.g. the
+ Ultrix one and possibly Winsock) indeed don't. */
+ {
+ uint32_t addr_ipv4 = (uint32_t)inet_addr (host);
+ if (addr_ipv4 != (uint32_t) -1)
+ {
+ /* No need to cache host->addr relation, just return the
+ address. */
+ char *vec[2];
+ vec[0] = (char *)&addr_ipv4;
+ vec[1] = NULL;
+ return address_list_from_ipv4_addresses (vec);
+ }
+ }
+#endif
- if (al)
+ /* Cache is normally on, but can be turned off with --no-dns-cache.
+ Don't cache passive lookups under IPv6. */
+ use_cache = opt.dns_cache;
+#ifdef ENABLE_IPV6
+ if (flags & LH_BIND)
+ use_cache = 0;
+#endif
+
+ /* Try to find the host in the cache so we don't need to talk to the
+ resolver. If LH_REFRESH is requested, remove HOST from the cache
+ instead. */
+ if (use_cache)
{
- DEBUGP (("Found %s in host_name_addresses_map (%p)\n", host, al));
- ++al->refcount;
- return al;
+ if (!(flags & LH_REFRESH))
+ {
+ al = cache_query (host);
+ if (al)
+ return al;
+ }
+ else
+ cache_remove (host);
}
+ /* No luck with the cache; resolve HOST. */
+
if (!silent)
logprintf (LOG_VERBOSE, _("Resolving %s... "), host);
- /* Look up the host using gethostbyname(). Note that we use
- gethostbyname() rather than ngethostbyname(), because we already
- know that the address is not numerical. */
- hptr = gethostbyname (host);
- if (!hptr)
- {
- if (!silent)
- logprintf (LOG_VERBOSE, _("failed: %s.\n"), herrmsg (h_errno));
- return NULL;
- }
+#ifdef ENABLE_IPV6
+ {
+ int err;
+ struct addrinfo hints, *res;
+
+ xzero (hints);
+ hints.ai_socktype = SOCK_STREAM;
+ if (opt.ipv4_only)
+ hints.ai_family = AF_INET;
+ else if (opt.ipv6_only)
+ hints.ai_family = AF_INET6;
+ else
+ {
+ hints.ai_family = AF_UNSPEC;
+#ifdef HAVE_GETADDRINFO_AI_ADDRCONFIG
+ hints.ai_flags |= AI_ADDRCONFIG;
+#else
+ /* On systems without AI_ADDRCONFIG, emulate it by manually
+ checking whether the system supports IPv6 sockets. */
+ if (!socket_has_inet6 ())
+ hints.ai_family = AF_INET;
+#endif
+ }
+ if (flags & LH_BIND)
+ hints.ai_flags |= AI_PASSIVE;
+
+ err = getaddrinfo_with_timeout (host, NULL, &hints, &res, opt.dns_timeout);
+ if (err != 0 || res == NULL)
+ {
+ if (!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);
+ if (!al)
+ {
+ logprintf (LOG_VERBOSE,
+ _("failed: No IPv4/IPv6 addresses for host.\n"));
+ return NULL;
+ }
+ }
+#else
+ {
+ struct hostent *hptr = gethostbyname_with_timeout (host, opt.dns_timeout);
+ if (!hptr)
+ {
+ if (!silent)
+ {
+ if (errno != ETIMEDOUT)
+ logprintf (LOG_VERBOSE, _("failed: %s.\n"),
+ host_errstr (h_errno));
+ else
+ logputs (LOG_VERBOSE, _("failed: timed out.\n"));
+ }
+ return NULL;
+ }
+ /* Do older systems have h_addr_list? */
+ al = address_list_from_ipv4_addresses (hptr->h_addr_list);
+ }
+#endif
+ /* Print the addresses determined by DNS lookup, but no more than
+ three. */
if (!silent)
- logprintf (LOG_VERBOSE, _("done.\n"));
-
- al = address_list_new (hptr->h_addr_list);
+ {
+ 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. */
- cache_host_lookup (host, al);
+ if (use_cache)
+ cache_store (host, al);
return al;
}
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)
{
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