- completely rewrote the wins_srv.c code. It is now much simpler, and

gives us a good grounding to properly support multiple wins servers
for different interfaces (which will be coming soon ...)

- fixed our wins registration failover code to actually do failover!
We were not trying to register with a secondary wins server at all
when the primary was down. We now fallback correctly.

- fixed the multi-homed name registration packets so that they work
even in a non-connected network (ie. when one of our interfaces is not
routable from the wins server. Yes, this really happens in the real
world).
(This used to be commit a049360d5b0d95a935b06aad43efc17d34de46dc)

1 files changed, 90 insertions, 303 deletions

diff --git a/source3/lib/wins_srv.c b/source3/lib/wins_srv.c
index 0181ee0956..cad0d06e49 100644
--- a/source3/lib/wins_srv.c
+++ b/source3/lib/wins_srv.c
@@ -1,7 +1,7 @@
 /*
    Unix SMB/CIFS implementation.
    Samba utility functions
-   Copyright (C) Andrew Tridgell 1992-1998
+   Copyright (C) Andrew Tridgell 1992-2002
    Copyright (C) Christopher R. Hertel 2000
 
    This program is free software; you can redistribute it and/or modify
@@ -21,319 +21,106 @@
 
 #include "includes.h"
 
-/* -------------------------------------------------------------------------- **
- * Discussion...
- *
- * This module implements WINS failover.
- *
- * Microsoft's WINS servers provide a feature called WINS replication,
- * which synchronises the WINS name databases between two or more servers. 
- * This means that the two servers can be used interchangably (more or
- * less). WINS replication is particularly useful if you are trying to
- * synchronise the WINS namespace between servers in remote locations, or
- * if your WINS servers tend to crash a lot. 
- *
- * WINS failover allows the client to 'switch' to a different WINS server
- * if the current WINS server mysteriously disappears.  On Windows
- * systems, this is typically represented as 'primary' and 'secondary'
- * WINS servers. 
- *
- * Failover only works if the WINS servers are synced.  If they are not,
- * then
- *   a) if the primary WINS server never fails the client will never 'see'
- *      the secondary (or tertiary or...) WINS server name space.
- *   b) if the primary *does* fail, the client will be entering an
- *      unfamiliar namespace.  The client itself will not be registered in
- *      that namespace and any names which match names in the previous
- *      space will likely resolve to different host IP addresses.
- *
- * One key thing to remember regarding WINS failover is that Samba does
- * not (yet) implement WINS replication.  For those interested, sniff port
- * 42 (TCP? UDP? ...dunno off hand) and see what two MS WINS servers do. 
- *
- * At this stage, only failover is implemented.  The next thing is to add
- * support for multi-WINS server registration and query (multi-membership).
- *
- * Multi-membership is a little wierd.  The idea is that the client can
- * register itself with multiple non-replicated WINS servers, and query
- * all of those servers (in a prescribed sequence) to resolve a name. 
- *
- * The implications of multi-membership are not quite clear.  Worth
- * trying, I suppose.  Changes will be needed in the name query and
- * registration code to accomodate this feature.  Also, there will need to
- * be some sort of syntax extension for the 'wins server' parameter in
- * smb.conf.  I'm thinking that a colon could be used as a separator. 
- *
- * Of course, for each WINS namespace there might be multiple, synced WINS
- * servers.  The change to this module would likely be the addition of a
- * linked list of linked lists.
- *
- * crh@samba.org
- */
 
-/* -------------------------------------------------------------------------- **
- * Defines... 
- *
- *   NECROMANCYCLE - The dead server retry period, in seconds.  When a WINS
- *                   server is declared dead, wait this many seconds before
- *                   attempting to communicate with it.
- */
+/* how long a server is marked dead for */
+#define DEATH_TIME 600
 
-#define NECROMANCYCLE 600   /* 600 seconds == 10 minutes. */
+/* a list of wins server that are marked dead. */
+static struct wins_dead {
+	struct in_addr ip;
+	time_t revival; /* when it will be revived */
+	struct wins_dead *next, *prev;
+} *dead_servers;
 
-/* -------------------------------------------------------------------------- **
- * Typedefs...
- */
 
-typedef struct
-  {
-  ubi_slNode     node;      /* Linked list node structure.                  */
-  time_t         mourning;  /* If > current time then server is dead, Jim.  */
-  char          *server;    /* DNS name or IP of NBNS server to query.      */
-  struct in_addr ip_addr;   /* Cache translated IP.                         */
-  } list_entry;
-
-/* -------------------------------------------------------------------------- **
- * Private, static variables.
- */
-
-static ubi_slNewList( wins_srv_list );
-
-/* -------------------------------------------------------------------------- **
- * Functions...
- */
-
-
-BOOL wins_srv_load_list( char *src )
-  /* ------------------------------------------------------------------------ **
-   * Create or recreate the linked list of failover WINS servers.
-   *
-   *  Input:  src - String of DNS names and/or IP addresses delimited by the
-   *                characters listed in LIST_SEP (see include/local.h).
-   *
-   *  Output: True if at least one name or IP could be parsed out of the
-   *          list, else False.
-   *
-   *  Notes:  There is no syntax checking done on the names or IPs.  We do
-   *          check to see if the field is an IP, in which case we copy it
-   *          to the ip_addr field of the entry.  Don't bother to to a host
-   *          name lookup on all names now.  They're done as needed in
-   *          wins_srv_ip().
-   * ------------------------------------------------------------------------ **
-   */
-  {
-  list_entry   *entry;
-  char         *p = src;
-  pstring       wins_id_bufr;
-  unsigned long count;
-
-  /* Empty the list. */
-  while( NULL != (entry =(list_entry *)ubi_slRemHead( wins_srv_list )) )
-    {
-    SAFE_FREE( entry->server );
-    SAFE_FREE( entry );
-    }
-  (void)ubi_slInitList( wins_srv_list );  /* shouldn't be needed */
-
-  /* Parse out the DNS names or IP addresses of the WINS servers. */
-  DEBUG( 4, ("wins_srv_load_list(): Building WINS server list:\n") );
-  while( next_token( &p, wins_id_bufr, LIST_SEP, sizeof( wins_id_bufr ) ) )
-    {
-    entry = (list_entry *)malloc( sizeof( list_entry ) );
-    if( NULL == entry )
-      {
-      DEBUG( 0, ("wins_srv_load_list(): malloc(list_entry) failed.\n") );
-      }
-    else
-      {
-      entry->mourning = 0;
-      /* Create a copy of the server name and store it in the list. */
-      if( NULL == (entry->server = strdup( wins_id_bufr )) )
-        {
-        SAFE_FREE( entry );
-        DEBUG( 0,
-          ("wins_srv_load_list(): strdup(\"%s\") failed.\n", wins_id_bufr) );
-        }
-      else
-        {
-        /* Add server to list.
-         * If the server name was actually an IP address we will store that
-         * too.  It it was a DNS name, we will wait until we need to use
-         * the WINS server before doing the DNS lookup.  Since this may be
-         * a list, and since we will reload the list whenever smb.conf is
-         * reloaded, there's no point in trying to look up names until we
-         * need them.  ...of course, once we do the lookup we will cache
-         * the result.  See wins_srv_ip().
-         */
-        if( is_ipaddress( wins_id_bufr ) )
-          entry->ip_addr = *interpret_addr2( wins_id_bufr );
-        else
-          entry->ip_addr = *interpret_addr2( "0.0.0.0" );
-        (void)ubi_slAddTail( wins_srv_list, entry );
-        DEBUGADD( 4, ("%s,\n", wins_id_bufr) );
-        }
-      }
-    }
-
-  count = ubi_slCount( wins_srv_list );
-  DEBUGADD( 4,
-    ( "%d WINS server%s listed.\n", (int)count, (1==count)?"":"s" ) );
-
-  return( (count > 0) ? True : False );
-  } /* wins_srv_load_list */
-
-
-struct in_addr wins_srv_ip( void )
-  /* ------------------------------------------------------------------------ **
-   * Return the IP address of an NBNS (WINS) server thought to be active.
-   *
-   *  Input:  none.
-   *
-   *  Output: An IP address in struct in_addr form.
-   *
-   *  Notes:  This function will return the IP address of the first available
-   *          NBNS (WINS) server.  The order of the list is determined in
-   *          smb.conf.  If all of the WINS servers have been marked 'dead'
-   *          then the zero IP (0.0.0.0) is returned.  The zero IP is not a
-   *          valid Unicast address on any system.
-   *
-   * ------------------------------------------------------------------------ **
-   */
-  {
-  time_t      now     = time(NULL);
-  list_entry *entry   = (list_entry *)ubi_slFirst( wins_srv_list );
-
-  while( NULL != entry )
-    {
-    if( now >= entry->mourning )        /* Found a live one. */
-      {
-      /* If we don't have the IP, look it up. */
-      if( is_zero_ip( entry->ip_addr ) )
-        entry->ip_addr = *interpret_addr2( entry->server );
-
-      /* If we still don't have the IP then kill it, else return it. */
-      if( is_zero_ip( entry->ip_addr ) )
-        entry->mourning = now + NECROMANCYCLE;
-      else
-        return( entry->ip_addr );
-      }
-    entry = (list_entry *)ubi_slNext( entry );
-    }
-
-  /* If there are no live entries, return the zero IP. */
-  return( *interpret_addr2( "0.0.0.0" ) );
-  } /* wins_srv_ip */
-
-
-char *wins_srv_name( void )
-  /* ------------------------------------------------------------------------ **
-   * Return the name of first live WINS server in the list.
-   *
-   *  Input:  none.
-   *
-   *  Output: A pointer to a string containing either the DNS name or IP
-   *          address of the WINS server as given in the WINS SERVER
-   *          parameter in smb.conf, or NULL if no (live) WINS servers are
-   *          in the list.
-   *
-   *  Notes:  This function will return the name of the first available
-   *          NBNS (WINS) server.  The order of the list is determined in
-   *          smb.conf.  If all of the WINS servers have been marked 'dead'
-   *          then NULL is returned.
-   *
-   *        - This function does not verify that the name can be mapped to
-   *          an IP address, or that the WINS server is running.
-   *
-   * ------------------------------------------------------------------------ **
-   */
-  {
-  time_t      now     = time(NULL);
-  list_entry *entry   = (list_entry *)ubi_slFirst( wins_srv_list );
-   
-  while( NULL != entry )
-    {
-    if( now >= entry->mourning )
-      return( entry->server );          /* Found a live one. */
-    entry = (list_entry *)ubi_slNext( entry );
-    }
-   
-  /* If there are no live entries, return NULL. */
-  return( NULL );
-  } /* wins_srv_name */
-
-
-void wins_srv_died( struct in_addr boothill_ip )
-  /* ------------------------------------------------------------------------ **
-   * Called to indicate that a specific WINS server has died.
-   *
-   *  Input:  boothill_ip - IP address of an NBNS (WINS) server that has
-   *                        failed.
-   *
-   *  Notes:  This function marks the record 'dead' for NECROMANCYCLE
-   *          seconds.  
-   *
-   * ------------------------------------------------------------------------ **
-   */
-  {
-  list_entry *entry;
+/*
+  see if an ip is on the dead list
+*/
+static int wins_is_dead(struct in_addr ip)
+{
+	struct wins_dead *d;
+	for (d=dead_servers; d; d=d->next) {
+		if (ip_equal(ip, d->ip)) {
+			/* it might be due for revival */
+			if (d->revival <= time(NULL)) {
+				DEBUG(4,("Reviving wins server %s\n", inet_ntoa(ip)));
+				DLIST_REMOVE(dead_servers, d);
+				free(d);
+				return 0;
+			}
+			return 1;
+		}
+	}
+	return 0;
+}
 
-  if( is_zero_ip( boothill_ip ) )
-    {
-    DEBUG( 4, ("wins_srv_died(): Invalid request to mark zero IP down.\n") );
-    return;
-    }
+/*
+  mark a wins server as temporarily dead
+*/
+void wins_srv_died(struct in_addr ip)
+{
+	struct wins_dead *d;
 
-  entry = (list_entry *)ubi_slFirst( wins_srv_list );
-  while( NULL != entry )
-    {
-    /* Match based on IP. */
-    if( ip_equal( boothill_ip, entry->ip_addr ) )
-      {
-      entry->mourning = time(NULL) + NECROMANCYCLE;
-      entry->ip_addr.s_addr = 0;  /* Force a re-lookup at re-birth. */
-      DEBUG( 2, ( "wins_srv_died(): WINS server %s appears to be down.\n", 
-                  entry->server ) );
-      return;
-      }
-    entry = (list_entry *)ubi_slNext( entry );
-    }
+	if (is_zero_ip(ip) || wins_is_dead(ip)) {
+		return;
+	}
 
-  if( DEBUGLVL( 1 ) )
-    {
-    dbgtext( "wins_srv_died(): Could not mark WINS server %s down.\n",
-              inet_ntoa( boothill_ip ) );
-    dbgtext( "Address not found in server list.\n" );
-    }
-  } /* wins_srv_died */
+	d = (struct wins_dead *)malloc(sizeof(*d));
+	if (!d) return;
 
+	d->ip = ip;
+	d->revival = time(NULL) + DEATH_TIME;
 
-unsigned long wins_srv_count( void )
-  /* ------------------------------------------------------------------------ **
-   * Return the total number of entries in the list, dead or alive.
-   * ------------------------------------------------------------------------ **
-   */
-  {
-  unsigned long count = ubi_slCount( wins_srv_list );
+	DEBUG(4,("Marking wins server %s dead for %u seconds\n", inet_ntoa(ip), DEATH_TIME));
 
-  if( DEBUGLVL( 8 ) )
-    {
-    list_entry *entry = (list_entry *)ubi_slFirst( wins_srv_list );
-    time_t      now   = time(NULL);
+	DLIST_ADD(dead_servers, d);
+}
 
-    dbgtext( "wins_srv_count: WINS status: %ld servers.\n", count );
-    while( NULL != entry )
-      {
-      dbgtext( "  %s <%s>: ", entry->server, inet_ntoa( entry->ip_addr ) );
-      if( now >= entry->mourning )
-        dbgtext( "alive\n" );
-      else
-        dbgtext( "dead for %d more seconds\n", (int)(entry->mourning - now) );
+/*
+  return the total number of wins servers, dead or not
+*/
+unsigned long wins_srv_count(void)
+{
+	char **list;
+	int count = 0;
 
-      entry = (list_entry *)ubi_slNext( entry );
-      }
-    }
+	list = lp_wins_server_list();
+	while (list && *list) {
+		count++;
+		list++;
+	}
 
-  return( count );
-  } /* wins_srv_count */
+	DEBUG(6,("Found %u wins servers in list\n", count));
+	return count;
+}
 
-/* ========================================================================== */
+/*
+  return the IP of the currently active wins server, or the zero IP otherwise
+*/
+struct in_addr wins_srv_ip(void)
+{
+	char **list;
+	struct in_addr ip;
+
+	list = lp_wins_server_list();
+	if (!list || !*list) {
+		zero_ip(&ip);
+		return ip;
+	}
+
+	/* find the first live one */
+	while (list && *list) {
+		ip = *interpret_addr2(*list);
+		if (!wins_is_dead(ip)) {
+			DEBUG(6,("Current wins server is %s\n", inet_ntoa(ip)));
+			return ip;
+		}
+		list++;
+	}
+
+	/* damn, they are all dead. Keep trying the primary until they revive */
+	list = lp_wins_server_list();
+	ip = *interpret_addr2(list[0]);
+
+	return ip;
+}