/* 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); if (!ret) { return NULL; } 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; }