# endif
#endif
-/* Mapping between known hosts and to lists of their addresses. */
-
-static struct hash_table *host_name_addresses_map;
-\f
/* Lists of IP addresses that result from running DNS queries. See
lookup_host for details. */
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. */
+
+/* Mapping between known hosts and to lists of their addresses. */
+static struct hash_table *host_name_addresses_map;
+
-/* 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. */
+/* 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);
#endif
}
-/* Remove HOST from Wget's DNS cache. Does nothing is HOST is not in
+/* Remove HOST from the DNS cache. Does nothing is HOST is not in
the cache. */
-void
-forget_host_lookup (const char *host)
+static void
+cache_remove (const char *host)
{
- struct address_list *al = hash_table_get (host_name_addresses_map, host);
+ struct address_list *al;
+ if (!host_name_addresses_map)
+ return;
+ al = hash_table_get (host_name_addresses_map, host);
if (al)
{
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.
you want to force lookup, call forget_host_lookup() prior to this
function, or set opt.dns_cache to 0 to globally disable caching.
- If SILENT is non-zero, progress messages are not printed. */
+ 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. */
struct address_list *
-lookup_host (const char *host, int silent)
+lookup_host (const char *host, int flags)
{
struct address_list *al = NULL;
+ int silent = flags & LH_SILENT;
+ int use_cache;
#ifndef ENABLE_IPV6
/* If we're not using getaddrinfo, first check if HOST specifies a
}
#endif
- /* Try to find the host in the cache. */
+ /* 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
- if (host_name_addresses_map)
+ /* 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)
{
- al = hash_table_get (host_name_addresses_map, host);
- if (al)
+ if (!(flags & LH_REFRESH))
{
- DEBUGP (("Found %s in host_name_addresses_map (%p)\n", host, al));
- ++al->refcount;
- return al;
+ al = cache_query (host);
+ if (al)
+ return al;
}
+ else
+ cache_remove (host);
}
- /* No luck with the cache; resolve the host name. */
+ /* No luck with the cache; resolve HOST. */
if (!silent)
logprintf (LOG_VERBOSE, _("Resolving %s... "), host);
xzero (hints);
hints.ai_socktype = SOCK_STREAM;
- hints.ai_family = AF_UNSPEC; /* #### should look at opt.ipv4_only
- and opt.ipv6_only */
- hints.ai_flags = 0;
+ hints.ai_family = AF_UNSPEC;
+ if (opt.ipv4_only && !opt.ipv6_only)
+ hints.ai_family = AF_INET;
+ else if (opt.ipv6_only && !opt.ipv4_only)
+ hints.ai_family = AF_INET6;
+
+#ifdef HAVE_GETADDRINFO_AI_ADDRCONFIG
+ /* Use AI_ADDRCONFIG where available. See init.c:defaults(). */
+ hints.ai_flags |= AI_ADDRCONFIG;
+#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)
freeaddrinfo (res);
if (!al)
{
- logprintf (LOG_VERBOSE, _("failed: No IPv4/IPv6 addresses.\n"));
+ logprintf (LOG_VERBOSE,
+ _("failed: No IPv4/IPv6 addresses for host.\n"));
return NULL;
}
}
}
/* Cache the lookup information. */
- if (opt.dns_cache)
- cache_host_lookup (host, al);
+ if (use_cache)
+ cache_store (host, al);
return al;
}
-
-/* Resolve HOST to get an address for use with bind(2). Do *not* use
- this for sockets to be used with connect(2).
-
- This is a function separate from lookup_host because the results it
- returns are different -- it uses the AI_PASSIVE flag to
- getaddrinfo. Because of this distinction, it doesn't store the
- results in the cache. It prints nothing and implements no timeouts
- because it should normally only be used with local addresses
- (typically "localhost" or numeric addresses of different local
- interfaces.)
-
- Without IPv6, this function just calls lookup_host. */
-
-struct address_list *
-lookup_host_passive (const char *host)
-{
-#ifdef ENABLE_IPV6
- struct address_list *al = NULL;
- int err;
- struct addrinfo hints, *res;
-
- xzero (hints);
- hints.ai_socktype = SOCK_STREAM;
- hints.ai_family = AF_UNSPEC; /* #### should look at opt.ipv4_only
- and opt.ipv6_only */
- hints.ai_flags = AI_PASSIVE;
-
- err = getaddrinfo (host, NULL, &hints, &res);
- if (err != 0 || res == NULL)
- return NULL;
- al = address_list_from_addrinfo (res);
- freeaddrinfo (res);
- return al;
-#else
- return lookup_host (host, 1);
-#endif
-}
\f
/* Determine whether a URL is acceptable to be followed, according to
a list of domains to accept. */
projects / wget / commitdiff