2 Unix SMB/CIFS implementation.
3 Samba wins server helper functions
4 Copyright (C) Andrew Tridgell 1992-2002
5 Copyright (C) Christopher R. Hertel 2000
6 Copyright (C) Tim Potter 2003
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
25 This is pretty much a complete rewrite of the earlier code. The main
26 aim of the rewrite is to add support for having multiple wins server
27 lists, so Samba can register with multiple groups of wins servers
28 and each group has a failover list of wins servers.
30 Central to the way it all works is the idea of a wins server
31 'tag'. A wins tag is a label for a group of wins servers. For
34 wins server = fred:192.168.2.10 mary:192.168.3.199 fred:192.168.2.61
36 then you would have two groups of wins servers, one tagged with the
37 name 'fred' and the other with the name 'mary'. I would usually
38 recommend using interface names instead of 'fred' and 'mary' but
39 they can be any alpha string.
41 Now, how does it all work. Well, nmbd needs to register each of its
42 IPs with each of its names once with each group of wins servers. So
43 it tries registering with the first one mentioned in the list, then
44 if that fails it marks that WINS server dead and moves onto the next
47 In the client code things are a bit different. As each of the groups
48 of wins servers is a separate name space we need to try each of the
49 groups until we either succeed or we run out of wins servers to
50 try. If we get a negative response from a wins server then that
51 means the name doesn't exist in that group, so we give up on that
52 group and move to the next group. If we don't get a response at all
53 then maybe the wins server is down, in which case we need to
54 failover to the next one for that group.
56 confused yet? (tridge)
59 /* how long a server is marked dead for */
60 #define DEATH_TIME 600
62 /* The list of dead wins servers is stored in gencache.tdb. Each server is
63 marked dead from the point of view of a given source address. We keep a
64 separate dead list for each src address to cope with multiple interfaces
65 that are not routable to each other.
68 #define WINS_SRV_FMT "WINS_SRV_DEAD/%s,%s" /* wins_ip,src_ip */
70 static char *wins_srv_keystr(struct in_addr wins_ip, struct in_addr src_ip)
72 char *keystr = NULL, *wins_ip_addr = NULL, *src_ip_addr = NULL;
74 wins_ip_addr = SMB_STRDUP(inet_ntoa(wins_ip));
75 src_ip_addr = SMB_STRDUP(inet_ntoa(src_ip));
77 if ( !wins_ip_addr || !src_ip_addr ) {
78 DEBUG(0,("wins_srv_keystr: malloc error\n"));
82 if (asprintf(&keystr, WINS_SRV_FMT, wins_ip_addr, src_ip_addr) == -1) {
83 DEBUG(0, (": ns_srv_keystr: malloc error for key string\n"));
87 SAFE_FREE(wins_ip_addr);
88 SAFE_FREE(src_ip_addr);
94 see if an ip is on the dead list
97 BOOL wins_srv_is_dead(struct in_addr wins_ip, struct in_addr src_ip)
99 char *keystr = wins_srv_keystr(wins_ip, src_ip);
102 /* If the key exists then the WINS server has been marked as dead */
104 result = gencache_get(keystr, NULL, NULL);
107 DEBUG(4, ("wins_srv_is_dead: %s is %s\n", inet_ntoa(wins_ip),
108 result ? "dead" : "alive"));
115 mark a wins server as being alive (for the moment)
117 void wins_srv_alive(struct in_addr wins_ip, struct in_addr src_ip)
119 char *keystr = wins_srv_keystr(wins_ip, src_ip);
121 gencache_del(keystr);
124 DEBUG(4, ("wins_srv_alive: marking wins server %s alive\n",
125 inet_ntoa(wins_ip)));
129 mark a wins server as temporarily dead
131 void wins_srv_died(struct in_addr wins_ip, struct in_addr src_ip)
135 if (is_zero_ip_v4(wins_ip) || wins_srv_is_dead(wins_ip, src_ip))
138 keystr = wins_srv_keystr(wins_ip, src_ip);
140 gencache_set(keystr, "DOWN", time(NULL) + DEATH_TIME);
144 DEBUG(4,("Marking wins server %s dead for %u seconds from source %s\n",
145 inet_ntoa(wins_ip), DEATH_TIME, inet_ntoa(src_ip)));
149 return the total number of wins servers, dead or not
151 unsigned wins_srv_count(void)
156 if (lp_wins_support()) {
157 /* simple - just talk to ourselves */
161 list = lp_wins_server_list();
162 for (count=0; list && list[count]; count++)
168 /* an internal convenience structure for an IP with a short string tag
176 parse an IP string that might be in tagged format
177 the result is a tagged_ip structure containing the tag
178 and the ip in in_addr format. If there is no tag then
181 static void parse_ip(struct tagged_ip *ip, const char *str)
183 char *s = strchr(str, ':');
185 fstrcpy(ip->tag, "*");
186 ip->ip = *interpret_addr2(str);
190 ip->ip = *interpret_addr2(s+1);
191 fstrcpy(ip->tag, str);
192 s = strchr(ip->tag, ':');
199 return the list of wins server tags. A 'tag' is used to distinguish
200 wins server as either belonging to the same name space or a separate
201 name space. Usually you would setup your 'wins server' option to
202 list one or more wins server per interface and use the interface
203 name as your tag, but you are free to use any tag you like.
205 char **wins_srv_tags(void)
211 if (lp_wins_support()) {
212 /* give the caller something to chew on. This makes
213 the rest of the logic simpler (ie. less special cases) */
214 ret = SMB_MALLOC_ARRAY(char *, 2);
215 if (!ret) return NULL;
216 ret[0] = SMB_STRDUP("*");
221 list = lp_wins_server_list();
225 /* yes, this is O(n^2) but n is very small */
226 for (i=0;list[i];i++) {
227 struct tagged_ip t_ip;
229 parse_ip(&t_ip, list[i]);
231 /* see if we already have it */
232 for (j=0;j<count;j++) {
233 if (strcmp(ret[j], t_ip.tag) == 0) {
239 /* we already have it. Move along */
243 /* add it to the list */
244 ret = SMB_REALLOC_ARRAY(ret, char *, count+2);
248 ret[count] = SMB_STRDUP(t_ip.tag);
249 if (!ret[count]) break;
254 /* make sure we null terminate */
261 /* free a list of wins server tags given by wins_srv_tags */
262 void wins_srv_tags_free(char **list)
266 for (i=0; list[i]; i++) {
274 return the IP of the currently active wins server for the given tag,
275 or the zero IP otherwise
277 struct in_addr wins_srv_ip_tag(const char *tag, struct in_addr src_ip)
281 struct tagged_ip t_ip;
283 /* if we are a wins server then we always just talk to ourselves */
284 if (lp_wins_support()) {
285 struct in_addr loopback_ip;
286 loopback_ip.s_addr = htonl(INADDR_LOOPBACK);
290 list = lp_wins_server_list();
291 if (!list || !list[0]) {
297 /* find the first live one for this tag */
298 for (i=0; list[i]; i++) {
299 parse_ip(&t_ip, list[i]);
300 if (strcmp(tag, t_ip.tag) != 0) {
301 /* not for the right tag. Move along */
304 if (!wins_srv_is_dead(t_ip.ip, src_ip)) {
306 fstrcpy(src_name, inet_ntoa(src_ip));
307 DEBUG(6,("Current wins server for tag '%s' with source %s is %s\n",
310 inet_ntoa(t_ip.ip)));
315 /* they're all dead - try the first one until they revive */
316 for (i=0; list[i]; i++) {
317 parse_ip(&t_ip, list[i]);
318 if (strcmp(tag, t_ip.tag) != 0) {
324 /* this can't happen?? */
325 zero_ip_v4(&t_ip.ip);
331 return a count of the number of IPs for a particular tag, including
334 unsigned wins_srv_count_tag(const char *tag)
339 /* if we are a wins server then we always just talk to ourselves */
340 if (lp_wins_support()) {
344 list = lp_wins_server_list();
345 if (!list || !list[0]) {
349 /* find the first live one for this tag */
350 for (i=0; list[i]; i++) {
351 struct tagged_ip t_ip;
352 parse_ip(&t_ip, list[i]);
353 if (strcmp(tag, t_ip.tag) == 0) {