From 292a51eda152f5e1885f38f3a811e956560f33f0 Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Fri, 13 Jun 2003 21:03:15 +0000
Subject: Forward port the app-head changes for dc name cache into 3.0. Jeremy.
 (This used to be commit 8bcc3116a22ce11b55a35f3363230f54bc5735fc)

---
 source3/libsmb/namequery_dc.c | 95 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 78 insertions(+), 17 deletions(-)

(limited to 'source3/libsmb/namequery_dc.c')

diff --git a/source3/libsmb/namequery_dc.c b/source3/libsmb/namequery_dc.c
index e98b728963..c162e34027 100644
--- a/source3/libsmb/namequery_dc.c
+++ b/source3/libsmb/namequery_dc.c
@@ -156,12 +156,11 @@ void flush_negative_conn_cache( void )
 }
 
 /****************************************************************************
- Utility function to return the name of a DC using RPC. The name is 
- guaranteed to be valid since we have already done a name_status_find on it 
- and we have checked our negative connection cache
+ Utility function to return the name of a DC. The name is guaranteed to be 
+ valid since we have already done a name_status_find on it 
  ***************************************************************************/
- 
-BOOL rpc_find_dc(const char *domain, fstring srv_name, struct in_addr *ip_out)
+
+BOOL get_dc_name(const char *domain, fstring srv_name, struct in_addr *ip_out)
 {
 	struct in_addr *ip_list = NULL, dc_ip, exclude_ip;
 	int count, i;
@@ -177,10 +176,12 @@ BOOL rpc_find_dc(const char *domain, fstring srv_name, struct in_addr *ip_out)
 	   
 	if ( use_pdc_only && get_pdc_ip(domain, &dc_ip) ) 
 	{
-		DEBUG(10,("rpc_find_dc: Atempting to lookup PDC to avoid sam sync delays\n"));
+		DEBUG(10,("get_dc_name: Atempting to lookup PDC to avoid sam sync delays\n"));
 		
-		if (name_status_find(domain, 0x1c, 0x20, dc_ip, srv_name)) {
-			/* makre we we haven't tried this on previously and failed */
+		/* check the connection cache and perform the node status 
+		   lookup only if the IP is not found to be bad */
+
+		if (name_status_find(domain, 0x1c, 0x20, dc_ip, srv_name) ) {
 			result = check_negative_conn_cache( domain, srv_name );
 			if ( NT_STATUS_IS_OK(result) )
 				goto done;
@@ -205,11 +206,71 @@ BOOL rpc_find_dc(const char *domain, fstring srv_name, struct in_addr *ip_out)
 		}
 	}
 
-	/* Pick a nice close server, but only if the list was not ordered */
-	if (!list_ordered && (count > 1) ) {
-		qsort(ip_list, count, sizeof(struct in_addr), QSORT_CAST ip_compare);
+	if ( !list_ordered ) 
+	{
+		/* 
+		 * Pick a nice close server. Look for DC on local net 
+		 * (assuming we don't have a list of preferred DC's)
+		 */
+		 
+		for (i = 0; i < count; i++) {
+			if (is_zero_ip(ip_list[i]))
+				continue;
+
+			if ( !is_local_net(ip_list[i]) )
+				continue;
+		
+			if (name_status_find(domain, 0x1c, 0x20, ip_list[i], srv_name)) {
+				result = check_negative_conn_cache( domain, srv_name );
+				if ( NT_STATUS_IS_OK(result) ) {
+					dc_ip = ip_list[i];
+					goto done;
+				}
+			}
+		
+			zero_ip(&ip_list[i]);
+		}
+
+		/*
+		 * Try looking in the name status cache for an
+		 * entry we already have. We know that already
+		 * resolved ok.
+		 */
+
+		for (i = 0; i < count; i++) {
+			if (is_zero_ip(ip_list[i]))
+				continue;
+
+			if (namecache_status_fetch(domain, 0x1c, 0x20,
+						ip_list[i], srv_name)) {
+				result = check_negative_conn_cache( domain, srv_name );
+				if ( NT_STATUS_IS_OK(result) ) {
+					dc_ip = ip_list[i];
+					goto done;
+				}
+			}
+		}
+		
+		/*
+		 * Secondly try and contact a random PDC/BDC.
+		 */
+
+		i = (sys_random() % count);
+
+		if ( !is_zero_ip(ip_list[i]) ) {
+			if ( name_status_find(domain, 0x1c, 0x20, ip_list[i], srv_name)) {
+				result = check_negative_conn_cache( domain, srv_name );
+				if ( NT_STATUS_IS_OK(result) ) {
+					dc_ip = ip_list[i];
+					goto done;
+				}
+			}
+			zero_ip(&ip_list[i]); /* Tried and failed. */
+		}
 	}
 
+	/* Finally return first DC that we can contact */
+
 	for (i = 0; i < count; i++) {
 		if (is_zero_ip(ip_list[i]))
 			continue;
@@ -220,20 +281,21 @@ BOOL rpc_find_dc(const char *domain, fstring srv_name, struct in_addr *ip_out)
 				dc_ip = ip_list[i];
 				goto done;
 			}
-		}
+		}		
 	}
 
-
 	SAFE_FREE(ip_list);
 
-	return False;
-done:
+	/* No-one to talk to )-: */
+	return False;		/* Boo-hoo */
+	
+ done:
 	/* We have the netbios name and IP address of a domain controller.
 	   Ideally we should sent a SAMLOGON request to determine whether
 	   the DC is alive and kicking.  If we can catch a dead DC before
 	   performing a cli_connect() we can avoid a 30-second timeout. */
 
-	DEBUG(3, ("rpc_find_dc: Returning DC %s (%s) for domain %s\n", srv_name,
+	DEBUG(3, ("get_dc_name: Returning DC %s (%s) for domain %s\n", srv_name,
 		  inet_ntoa(dc_ip), domain));
 
 	*ip_out = dc_ip;
@@ -242,4 +304,3 @@ done:
 
 	return True;
 }
-
-- 
cgit