From: David Hankins <dhankins@isc.org>
Date: Tue, 19 Aug 2008 18:00:24 +0000 (+0000)
Subject: - A partner-down failover server no longer emits 'peer holds all free leases'
X-Git-Tag: v4_1_0a2~3
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8fbb55ff3f1b770adfa91681f49a652b2e5de45c;p=thirdparty%2Fdhcp.git

- A partner-down failover server no longer emits 'peer holds all free leases'
  if it is able to newly-allocate one of the peer's leases.  [ISC-Bugs #18437]
---

diff --git a/RELNOTES b/RELNOTES
index d9f71f7a9..6223570b0 100644
--- a/RELNOTES
+++ b/RELNOTES
@@ -60,6 +60,9 @@ work on other platforms. Please report any problems and suggested fixes to
 
 - The server wasn't always sending the FQDN option when it should.
 
+- A partner-down failover server no longer emits 'peer holds all free leases'
+  if it is able to newly-allocate one of the peer's leases.
+
 - Fixed a coredump when adding a class via OMAPI.
 
 - Check whether files are zero length before trying to parse them.
diff --git a/server/dhcp.c b/server/dhcp.c
index 30097f552..72e34382c 100644
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -3924,18 +3924,47 @@ int allocate_lease (struct lease **lp, struct packet *packet,
 		 * XXX result in its being allocated. */
 		/* Skip to the most expired lease in the pool that is not
 		 * owned by a failover peer. */
-		if (pool -> failover_peer) {
-			if (pool -> failover_peer -> i_am == primary) {
-				if (pool -> backup)
-					*peer_has_leases = 1;
-				candl = pool -> free;
-				if (!candl)
-					candl = pool -> abandoned;
+		if (pool->failover_peer != NULL) {
+			if (pool->failover_peer->i_am == primary) {
+				candl = pool->free;
+
+				/*
+				 * In normal operation, we never want to touch
+				 * the peer's leases.  In partner-down 
+				 * operation, we need to be able to pick up
+				 * the peer's leases after STOS+MCLT.
+				 */
+				if (pool->backup != NULL) {
+					if (((candl == NULL) ||
+					     (candl->ends >
+					      pool->backup->ends)) &&
+					    lease_mine_to_reallocate(
+							    pool->backup)) {
+						candl = pool->backup;
+					} else {
+						*peer_has_leases = 1;
+					}
+				}
 			} else {
-				if (pool -> free)
-					*peer_has_leases = 1;
-				candl = pool -> backup;
+				candl = pool->backup;
+
+				if (pool->free != NULL) {
+					if (((candl == NULL) ||
+					     (candl->ends >
+					      pool->free->ends)) &&
+					    lease_mine_to_reallocate(
+							    pool->free)) {
+						candl = pool->free;
+					} else {
+						*peer_has_leases = 1;
+					}
+				}
 			}
+
+			if ((candl == NULL) &&
+			    (pool->abandoned != NULL) &&
+			    lease_mine_to_reallocate(pool->abandoned))
+				candl = pool->abandoned;
 		} else
 #endif
 		{
@@ -3945,6 +3974,15 @@ int allocate_lease (struct lease **lp, struct packet *packet,
 				candl = pool -> abandoned;
 		}
 
+		/*
+		 * XXX: This may not match with documented expectation.
+		 * It's expected that when we OFFER a lease, we set its
+		 * ends time forward 2 minutes so that it gets sorted to
+		 * the end of its free list (avoiding a similar allocation
+		 * to another client).  It is not expected that we issue a
+		 * "no free leases" error when the last lease has been
+		 * offered, but it's not exactly broken either.
+		 */
 		if (!candl || (candl -> ends > cur_time))
 			continue;