--- /dev/null
+/*
+ Unix SMB/CIFS implementation.
+ Samba wins server helper functions
+ Copyright (C) Andrew Tridgell 1992-2002
+ Copyright (C) Christopher R. Hertel 2000
+ Copyright (C) Tim Potter 2003
+
+ This program 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.
+
+ This program 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 this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "includes.h"
+
+extern struct in_addr loopback_ip;
+
+/*
+ This is pretty much a complete rewrite of the earlier code. The main
+ aim of the rewrite is to add support for having multiple wins server
+ lists, so Samba can register with multiple groups of wins servers
+ and each group has a failover list of wins servers.
+
+ Central to the way it all works is the idea of a wins server
+ 'tag'. A wins tag is a label for a group of wins servers. For
+ example if you use
+
+ wins server = fred:192.168.2.10 mary:192.168.3.199 fred:192.168.2.61
+
+ then you would have two groups of wins servers, one tagged with the
+ name 'fred' and the other with the name 'mary'. I would usually
+ recommend using interface names instead of 'fred' and 'mary' but
+ they can be any alpha string.
+
+ Now, how does it all work. Well, nmbd needs to register each of its
+ IPs with each of its names once with each group of wins servers. So
+ it tries registering with the first one mentioned in the list, then
+ if that fails it marks that WINS server dead and moves onto the next
+ one.
+
+ In the client code things are a bit different. As each of the groups
+ of wins servers is a separate name space we need to try each of the
+ groups until we either succeed or we run out of wins servers to
+ try. If we get a negative response from a wins server then that
+ means the name doesn't exist in that group, so we give up on that
+ group and move to the next group. If we don't get a response at all
+ then maybe the wins server is down, in which case we need to
+ failover to the next one for that group.
+
+ confused yet? (tridge)
+*/
+
+/* how long a server is marked dead for */
+#define DEATH_TIME 600
+
+/* The list of dead wins servers is stored in gencache.tdb. Each server is
+ marked dead from the point of view of a given source address. We keep a
+ separate dead list for each src address to cope with multiple interfaces
+ that are not routable to each other.
+ */
+
+#define WINS_SRV_FMT "WINS_SRV_DEAD/%s,%s" /* wins_ip,src_ip */
+
+static char *wins_srv_keystr(struct in_addr wins_ip, struct in_addr src_ip)
+{
+ char *keystr = NULL, *wins_ip_addr = NULL, *src_ip_addr = NULL;
+
+ wins_ip_addr = SMB_STRDUP(inet_ntoa(wins_ip));
+ src_ip_addr = SMB_STRDUP(inet_ntoa(src_ip));
+
+ if ( !wins_ip_addr || !src_ip_addr ) {
+ DEBUG(0,("wins_srv_keystr: malloc error\n"));
+ goto done;
+ }
+
+ if (asprintf(&keystr, WINS_SRV_FMT, wins_ip_addr, src_ip_addr) == -1) {
+ DEBUG(0, (": ns_srv_keystr: malloc error for key string\n"));
+ }
+
+done:
+ SAFE_FREE(wins_ip_addr);
+ SAFE_FREE(src_ip_addr);
+
+ return keystr;
+}
+
+/*
+ see if an ip is on the dead list
+*/
+
+BOOL wins_srv_is_dead(struct in_addr wins_ip, struct in_addr src_ip)
+{
+ char *keystr = wins_srv_keystr(wins_ip, src_ip);
+ BOOL result;
+
+ /* If the key exists then the WINS server has been marked as dead */
+
+ result = gencache_get(keystr, NULL, NULL);
+ SAFE_FREE(keystr);
+
+ DEBUG(4, ("wins_srv_is_dead: %s is %s\n", inet_ntoa(wins_ip),
+ result ? "dead" : "alive"));
+
+ return result;
+}
+
+
+/*
+ mark a wins server as being alive (for the moment)
+*/
+void wins_srv_alive(struct in_addr wins_ip, struct in_addr src_ip)
+{
+ char *keystr = wins_srv_keystr(wins_ip, src_ip);
+
+ gencache_del(keystr);
+ SAFE_FREE(keystr);
+
+ DEBUG(4, ("wins_srv_alive: marking wins server %s alive\n",
+ inet_ntoa(wins_ip)));
+}
+
+/*
+ mark a wins server as temporarily dead
+*/
+void wins_srv_died(struct in_addr wins_ip, struct in_addr src_ip)
+{
+ char *keystr;
+
+ if (is_zero_ip(wins_ip) || wins_srv_is_dead(wins_ip, src_ip))
+ return;
+
+ keystr = wins_srv_keystr(wins_ip, src_ip);
+
+ gencache_set(keystr, "DOWN", time(NULL) + DEATH_TIME);
+
+ SAFE_FREE(keystr);
+
+ DEBUG(4,("Marking wins server %s dead for %u seconds from source %s\n",
+ inet_ntoa(wins_ip), DEATH_TIME, inet_ntoa(src_ip)));
+}
+
+/*
+ return the total number of wins servers, dead or not
+*/
+unsigned wins_srv_count(void)
+{
+ const char **list;
+ int count = 0;
+
+ if (lp_wins_support()) {
+ /* simple - just talk to ourselves */
+ return 1;
+ }
+
+ list = lp_wins_server_list();
+ for (count=0; list && list[count]; count++)
+ /* nop */ ;
+
+ return count;
+}
+
+/* an internal convenience structure for an IP with a short string tag
+ attached */
+struct tagged_ip {
+ fstring tag;
+ struct in_addr ip;
+};
+
+/*
+ parse an IP string that might be in tagged format
+ the result is a tagged_ip structure containing the tag
+ and the ip in in_addr format. If there is no tag then
+ use the tag '*'
+*/
+static void parse_ip(struct tagged_ip *ip, const char *str)
+{
+ char *s = strchr(str, ':');
+ if (!s) {
+ fstrcpy(ip->tag, "*");
+ ip->ip = *interpret_addr2(str);
+ return;
+ }
+
+ ip->ip = *interpret_addr2(s+1);
+ fstrcpy(ip->tag, str);
+ s = strchr(ip->tag, ':');
+ if (s) *s = 0;
+}
+
+
+
+/*
+ return the list of wins server tags. A 'tag' is used to distinguish
+ wins server as either belonging to the same name space or a separate
+ name space. Usually you would setup your 'wins server' option to
+ list one or more wins server per interface and use the interface
+ name as your tag, but you are free to use any tag you like.
+*/
+char **wins_srv_tags(void)
+{
+ char **ret = NULL;
+ int count=0, i, j;
+ const char **list;
+
+ if (lp_wins_support()) {
+ /* give the caller something to chew on. This makes
+ the rest of the logic simpler (ie. less special cases) */
+ ret = SMB_MALLOC_ARRAY(char *, 2);
+ if (!ret) return NULL;
+ ret[0] = SMB_STRDUP("*");
+ ret[1] = NULL;
+ return ret;
+ }
+
+ list = lp_wins_server_list();
+ if (!list)
+ return NULL;
+
+ /* yes, this is O(n^2) but n is very small */
+ for (i=0;list[i];i++) {
+ struct tagged_ip t_ip;
+
+ parse_ip(&t_ip, list[i]);
+
+ /* see if we already have it */
+ for (j=0;j<count;j++) {
+ if (strcmp(ret[j], t_ip.tag) == 0) {
+ break;
+ }
+ }
+
+ if (j != count) {
+ /* we already have it. Move along */
+ continue;
+ }
+
+ /* add it to the list */
+ ret = SMB_REALLOC_ARRAY(ret, char *, count+2);
+ ret[count] = SMB_STRDUP(t_ip.tag);
+ if (!ret[count]) break;
+ count++;
+ }
+
+ if (count) {
+ /* make sure we null terminate */
+ ret[count] = NULL;
+ }
+
+ return ret;
+}
+
+/* free a list of wins server tags given by wins_srv_tags */
+void wins_srv_tags_free(char **list)
+{
+ int i;
+ if (!list) return;
+ for (i=0; list[i]; i++) {
+ free(list[i]);
+ }
+ free(list);
+}
+
+
+/*
+ return the IP of the currently active wins server for the given tag,
+ or the zero IP otherwise
+*/
+struct in_addr wins_srv_ip_tag(const char *tag, struct in_addr src_ip)
+{
+ const char **list;
+ int i;
+ struct tagged_ip t_ip;
+
+ /* if we are a wins server then we always just talk to ourselves */
+ if (lp_wins_support()) {
+ return loopback_ip;
+ }
+
+ list = lp_wins_server_list();
+ if (!list || !list[0]) {
+ struct in_addr ip;
+ zero_ip(&ip);
+ return ip;
+ }
+
+ /* find the first live one for this tag */
+ for (i=0; list[i]; i++) {
+ parse_ip(&t_ip, list[i]);
+ if (strcmp(tag, t_ip.tag) != 0) {
+ /* not for the right tag. Move along */
+ continue;
+ }
+ if (!wins_srv_is_dead(t_ip.ip, src_ip)) {
+ fstring src_name;
+ fstrcpy(src_name, inet_ntoa(src_ip));
+ DEBUG(6,("Current wins server for tag '%s' with source %s is %s\n",
+ tag,
+ src_name,
+ inet_ntoa(t_ip.ip)));
+ return t_ip.ip;
+ }
+ }
+
+ /* they're all dead - try the first one until they revive */
+ for (i=0; list[i]; i++) {
+ parse_ip(&t_ip, list[i]);
+ if (strcmp(tag, t_ip.tag) != 0) {
+ continue;
+ }
+ return t_ip.ip;
+ }
+
+ /* this can't happen?? */
+ zero_ip(&t_ip.ip);
+ return t_ip.ip;
+}
+
+
+/*
+ return a count of the number of IPs for a particular tag, including
+ dead ones
+*/
+unsigned wins_srv_count_tag(const char *tag)
+{
+ const char **list;
+ int i, count=0;
+
+ /* if we are a wins server then we always just talk to ourselves */
+ if (lp_wins_support()) {
+ return 1;
+ }
+
+ list = lp_wins_server_list();
+ if (!list || !list[0]) {
+ return 0;
+ }
+
+ /* find the first live one for this tag */
+ for (i=0; list[i]; i++) {
+ struct tagged_ip t_ip;
+ parse_ip(&t_ip, list[i]);
+ if (strcmp(tag, t_ip.tag) == 0) {
+ count++;
+ }
+ }
+
+ return count;
+}
projects / samba / blobdiff