Merge changes between 3.0rc7 and 3.0rc8pl2.

1 files changed, 257 insertions, 150 deletions

diff --git a/server/dhcp.c b/server/dhcp.c
index 1b4f7317..095d78a7 100644
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -43,7 +43,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: dhcp.c,v 1.193 2001/05/17 19:04:05 mellon Exp $ Copyright (c) 1995-2001 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: dhcp.c,v 1.194 2001/06/27 00:31:07 mellon Exp $ Copyright (c) 1995-2001 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -52,6 +52,18 @@ int outstanding_pings;
 
 static char dhcp_message [256];
 
+static const char *dhcp_type_names [] = { 
+	"DHCPDISCOVER",
+	"DHCPOFFER",
+	"DHCPREQUEST",
+	"DHCPDECLINE",
+	"DHCPACK",
+	"DHCPNAK",
+	"DHCPRELEASE",
+	"DHCPINFORM"
+};
+const int dhcp_type_name_max = ((sizeof dhcp_type_names) / sizeof (char *));
+
 #if defined (TRACING)
 # define send_packet trace_packet_send
 #endif
@@ -68,18 +80,6 @@ void dhcp (packet)
 	if (!locate_network (packet) &&
 	    packet -> packet_type != DHCPREQUEST &&
 	    packet -> packet_type != DHCPINFORM) {
-		static const char *dhcp_type_names [] = { 
-			"DHCPDISCOVER",
-			"DHCPOFFER",
-			"DHCPREQUEST",
-			"DHCPDECLINE",
-			"DHCPACK",
-			"DHCPNAK",
-			"DHCPRELEASE",
-			"DHCPINFORM"
-		};
-		const int dhcp_type_name_max = ((sizeof dhcp_type_names) / 
-						sizeof (char *));
 		const char *s;
 		char typebuf [32];
 		errmsg = "unknown network segment";
@@ -296,6 +296,36 @@ void dhcpdiscover (packet, ms_nulltp)
 		goto out;
 	}
 
+#if defined (FAILOVER_PROTOCOL)
+	if (lease && lease -> pool && lease -> pool -> failover_peer) {
+		peer = lease -> pool -> failover_peer;
+
+		/* If the lease is ours to allocate, then allocate it,
+		   but set the allocatedp flag. */
+		if (lease_mine_to_reallocate (lease))
+			allocatedp = 1;
+
+		/* If the lease is active, do load balancing to see who
+		   allocates the lease (if it's active, it already belongs
+		   to the client, or we wouldn't have gotten it from
+		   find_lease (). */
+		else if (lease -> binding_state == FTS_ACTIVE &&
+			 (peer -> service_state != cooperating ||
+			  load_balance_mine (packet, peer)))
+			;
+
+		/* Otherwise, we can't let the client have this lease. */
+		else {
+#if defined (DEBUG_FIND_LEASE)
+		    log_debug ("discarding %s - %s",
+			       piaddr (lease -> ip_addr),
+			       binding_state_print (lease -> binding_state));
+#endif
+		    lease_dereference (&lease, MDL);
+		}
+	}
+#endif
+
 	/* If we didn't find a lease, try to allocate one... */
 	if (!lease) {
 		if (!allocate_lease (&lease, packet,
@@ -467,9 +497,14 @@ void dhcprequest (packet, ms_nulltp, ip_lease)
 		   If it's RENEWING, we are the only server to hear it, so
 		   we have to serve it.   If it's REBINDING, it's out of
 		   communication with the other server, so there's no point
-		   in waiting to serve it. */
+		   in waiting to serve it.    However, if the lease we're
+		   offering is not a free lease, then we may be the only
+		   server that can offer it, so we can't load balance if
+		   the lease isn't in the free or backup state. */
 		if (peer -> service_state == cooperating &&
-		    !packet -> raw -> ciaddr.s_addr) {
+		    !packet -> raw -> ciaddr.s_addr &&
+		    (lease -> binding_state == FTS_FREE ||
+		     lease -> binding_state == FTS_BACKUP)) {
 			if (!load_balance_mine (packet, peer)) {
 				log_debug ("%s: load balance to peer %s",
 					   msgbuf, peer -> name);
@@ -479,13 +514,36 @@ void dhcprequest (packet, ms_nulltp, ip_lease)
 
 		/* Don't let a client allocate a lease using DHCPREQUEST
 		   if the lease isn't ours to allocate. */
-		if ((lease -> binding_state == FTS_FREE &&
-		     peer -> i_am == secondary) ||
-		    (lease -> binding_state == FTS_BACKUP &&
-		     peer -> i_am == primary)) {
-			log_debug ("%s: expired", msgbuf);
+		if ((lease -> binding_state == FTS_FREE ||
+		     lease -> binding_state == FTS_BACKUP) &&
+		    !lease_mine_to_reallocate (lease)) {
+			log_debug ("%s: lease owned by peer", msgbuf);
 			goto out;
 		}
+
+		/* At this point it's possible that we will get a broadcast
+		   DHCPREQUEST for a lease that we didn't offer, because
+		   both we and the peer are in a position to offer it.
+		   In that case, we probably shouldn't answer.   In order
+		   to not answer, we would have to compare the server
+		   identifier sent by the client with the list of possible
+		   server identifiers we can send, and if the client's
+		   identifier isn't on the list, drop the DHCPREQUEST.
+		   We aren't currently doing that for two reasons - first,
+		   it's not clear that all clients do the right thing
+		   with respect to sending the client identifier, which
+		   could mean that we might simply not respond to a client
+		   that is depending on us to respond.   Secondly, we allow
+		   the user to specify the server identifier to send, and
+		   we don't enforce that the server identifier should be
+		   one of our IP addresses.   This is probably not a big
+		   deal, but it's theoretically an issue.
+
+		   The reason we care about this is that if both servers
+		   send a DHCPACK to the DHCPREQUEST, they are then going
+		   to send dueling BNDUPD messages, which could cause
+		   trouble.   I think it causes no harm, but it seems
+		   wrong. */
 	} else
 		peer = (dhcp_failover_state_t *)0;
 #endif
@@ -978,7 +1036,8 @@ void dhcpinform (packet, ms_nulltp)
 	i = DHO_DHCP_MESSAGE_TYPE;
 	oc = (struct option_cache *)0;
 	if (option_cache_allocate (&oc, MDL)) {
-		if (make_const_data (&oc -> expression, &dhcpack, 1, 0, 0)) {
+		if (make_const_data (&oc -> expression,
+				     &dhcpack, 1, 0, 0, MDL)) {
 			oc -> option = dhcp_universe.options [i];
 			save_option (&dhcp_universe, options, oc);
 		}
@@ -995,7 +1054,7 @@ void dhcpinform (packet, ms_nulltp)
 			     ((unsigned char *)
 			      &packet -> interface -> primary_address),
 			     sizeof packet -> interface -> primary_address,
-			     0, 0)) {
+			     0, 0, MDL)) {
 				oc -> option =
 					dhcp_universe.options [i];
 				save_option (&dhcp_universe,
@@ -1027,7 +1086,8 @@ void dhcpinform (packet, ms_nulltp)
 		if (option_cache_allocate (&oc, MDL)) {
 			if (make_const_data (&oc -> expression,
 					     subnet -> netmask.iabuf,
-					     subnet -> netmask.len, 0, 0)) {
+					     subnet -> netmask.len,
+					     0, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe, options, oc);
 			}
@@ -1190,7 +1250,8 @@ void nak_lease (packet, cip)
 		option_state_dereference (&options, MDL);
 		return;
 	}
-	if (!make_const_data (&oc -> expression, &nak, sizeof nak, 0, 0)) {
+	if (!make_const_data (&oc -> expression, &nak, sizeof nak,
+			      0, 0, MDL)) {
 		log_error ("No memory for expr_const expression.");
 		option_cache_dereference (&oc, MDL);
 		option_state_dereference (&options, MDL);
@@ -1208,7 +1269,7 @@ void nak_lease (packet, cip)
 	}
 	if (!make_const_data (&oc -> expression,
 			      (unsigned char *)dhcp_message,
-			      strlen (dhcp_message), 1, 0)) {
+			      strlen (dhcp_message), 1, 0, MDL)) {
 		log_error ("No memory for expr_const expression.");
 		option_cache_dereference (&oc, MDL);
 		option_state_dereference (&options, MDL);
@@ -1228,7 +1289,7 @@ void nak_lease (packet, cip)
 			     ((unsigned char *)
 			      &packet -> interface -> primary_address),
 			     sizeof packet -> interface -> primary_address,
-			     0, 0)) {
+			     0, 0, MDL)) {
 				oc -> option =
 					dhcp_universe.options [i];
 				save_option (&dhcp_universe, options, oc);
@@ -1492,83 +1553,96 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 					   packet -> options,
 					   state -> options, &lease -> scope,
 					   oc, MDL)) {
-		struct lease *seek;
-		if (lease -> uid_len) {
-			do {
-				seek = (struct lease *)0;
-				find_lease_by_uid (&seek, lease -> uid,
-						   lease -> uid_len, MDL);
-				if (!seek || (seek == lease && !seek -> n_uid))
-					break;
-				next = (struct lease *)0;
-
-				/* Don't release expired leases, and don't
-				   release the lease we're going to assign. */
-				next = (struct lease *)0;
-				while (seek) {
-					if (seek -> n_uid)
-					    lease_reference (&next,
-							     seek -> n_uid,
-							     MDL);
-					if (seek != lease &&
-					    seek -> ends > cur_time)
-						break;
-					lease_dereference (&seek, MDL);
-					if (next) {
-					    lease_reference (&seek, next, MDL);
-					    lease_dereference (&next, MDL);
-					}
-				}
-				if (next)
-					lease_dereference (&next, MDL);
-				if (seek) {
-					release_lease (seek, packet);
-					lease_dereference (&seek, MDL);
-				} else
-					break;
-			} while (1);
-		}
-		if (!lease -> uid_len ||
-		    (lease -> host &&
-		     !lease -> host -> client_identifier.len &&
-		     (oc = lookup_option (&server_universe, state -> options,
-					  SV_DUPLICATES)) &&
-		     !evaluate_boolean_option_cache (&ignorep, packet, lease,
-						     (struct client_state *)0,
-						     packet -> options,
-						     state -> options,
-						     &lease -> scope,
-						     oc, MDL))) {
-			do {
-				seek = (struct lease *)0;
-				find_lease_by_hw_addr
-					(&seek, lease -> hardware_addr.hbuf,
-					 lease -> hardware_addr.hlen, MDL);
-				if (!seek || (seek == lease && !seek -> n_hw))
-					break;
-				next = (struct lease *)0;
-				while (seek) {
-				    if (seek -> n_hw)
-					lease_reference (&next,
-							 seek -> n_hw, MDL);
-					if (seek != lease &&
-					    seek -> ends > cur_time)
-						break;
-					lease_dereference (&seek, MDL);
-					if (next) {
-					    lease_reference (&seek, next, MDL);
-					    lease_dereference (&next, MDL);
-					}
-				}
-				if (next)
-					lease_dereference (&next, MDL);
-				if (seek) {
-					release_lease (seek, packet);
-					lease_dereference (&seek, MDL);
-				} else
-					break;
-			} while (1);
-		}
+	    struct lease *seek;
+	    if (lease -> uid_len) {
+		do {
+		    seek = (struct lease *)0;
+		    find_lease_by_uid (&seek, lease -> uid,
+				       lease -> uid_len, MDL);
+		    if (!seek)
+			break;
+		    if (seek == lease && !seek -> n_uid) {
+			lease_dereference (&seek, MDL);
+			break;
+		    }
+		    next = (struct lease *)0;
+
+		    /* Don't release expired leases, and don't
+		       release the lease we're going to assign. */
+		    next = (struct lease *)0;
+		    while (seek) {
+			if (seek -> n_uid)
+			    lease_reference (&next, seek -> n_uid, MDL);
+			if (seek != lease &&
+			    seek -> binding_state != FTS_RELEASED &&
+			    seek -> binding_state != FTS_EXPIRED &&
+			    seek -> binding_state != FTS_RESET &&
+			    seek -> binding_state != FTS_FREE &&
+			    seek -> binding_state != FTS_BACKUP)
+				break;
+			lease_dereference (&seek, MDL);
+			if (next) {
+			    lease_reference (&seek, next, MDL);
+			    lease_dereference (&next, MDL);
+			}
+		    }
+		    if (next)
+			lease_dereference (&next, MDL);
+		    if (seek) {
+			release_lease (seek, packet);
+			lease_dereference (&seek, MDL);
+		    } else
+			break;
+		} while (1);
+	    }
+	    if (!lease -> uid_len ||
+		(lease -> host &&
+		 !lease -> host -> client_identifier.len &&
+		 (oc = lookup_option (&server_universe, state -> options,
+				      SV_DUPLICATES)) &&
+		 !evaluate_boolean_option_cache (&ignorep, packet, lease,
+						 (struct client_state *)0,
+						 packet -> options,
+						 state -> options,
+						 &lease -> scope,
+						 oc, MDL))) {
+		do {
+		    seek = (struct lease *)0;
+		    find_lease_by_hw_addr
+			    (&seek, lease -> hardware_addr.hbuf,
+			     lease -> hardware_addr.hlen, MDL);
+		    if (!seek)
+			    break;
+		    if (seek == lease && !seek -> n_hw) {
+			    lease_dereference (&seek, MDL);
+			    break;
+		    }
+		    next = (struct lease *)0;
+		    while (seek) {
+			if (seek -> n_hw)
+			    lease_reference (&next, seek -> n_hw, MDL);
+			if (seek != lease &&
+			    seek -> binding_state != FTS_RELEASED &&
+			    seek -> binding_state != FTS_EXPIRED &&
+			    seek -> binding_state != FTS_RESET &&
+			    seek -> binding_state != FTS_FREE &&
+			    seek -> binding_state != FTS_BACKUP)
+				break;
+			lease_dereference (&seek, MDL);
+			if (next) {
+			    lease_reference (&seek, next, MDL);
+			    lease_dereference (&next, MDL);
+			}
+		    }
+		    if (next)
+			lease_dereference (&next, MDL);
+		    if (seek) {
+			release_lease (seek, packet);
+			lease_dereference (&seek, MDL);
+		    } else
+			break;
+		} while (1);
+	    }
 	}
 	
 
@@ -1859,7 +1933,8 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 				/* Here we're assuming that if we don't have
 				   to update tstp, there's already an update
 				   queued.   May want to revisit this.  */
-				if (cur_time + lease_time > lease -> tstp)
+				if (peer -> me.state != partner_down &&
+				    cur_time + lease_time > lease -> tstp)
 					lt -> tstp = (cur_time + lease_time +
 						      peer -> mclt / 2);
 
@@ -1902,7 +1977,13 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 			lt -> ends = when;
 		else
 			lt -> ends = state -> offered_expiry;
-		lt -> next_binding_state = FTS_ACTIVE;
+
+		/* Don't make lease active until we actually get a
+		   DHCPREQUEST. */
+		if (offer == DHCPACK)
+			lt -> next_binding_state = FTS_ACTIVE;
+		else
+			lt -> next_binding_state = lease -> binding_state;
 	} else {
 		lease_time = MAX_TIME - cur_time;
 
@@ -2162,7 +2243,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 		oc = (struct option_cache *)0;
 		if (option_cache_allocate (&oc, MDL)) {
 			if (make_const_data (&oc -> expression,
-					     &state -> offer, 1, 0, 0)) {
+					     &state -> offer, 1, 0, 0, MDL)) {
 				oc -> option =
 					dhcp_universe.options [i];
 				save_option (&dhcp_universe,
@@ -2181,7 +2262,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 				     ((unsigned char *)
 				      &state -> ip -> primary_address),
 				     sizeof state -> ip -> primary_address,
-				     0, 0)) {
+				     0, 0, MDL)) {
 					oc -> option =
 						dhcp_universe.options [i];
 					save_option (&dhcp_universe,
@@ -2225,7 +2306,8 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 		if (option_cache_allocate (&oc, MDL)) {
 			if (make_const_data (&oc -> expression,
 					     (unsigned char *)&state -> expiry,
-					     sizeof state -> expiry, 0, 0)) {
+					     sizeof state -> expiry,
+					     0, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe,
 					     state -> options, oc);
@@ -2246,7 +2328,8 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 			if (make_const_data (&oc -> expression,
 					     (unsigned char *)
 					     &state -> renewal,
-					     sizeof state -> renewal, 0, 0)) {
+					     sizeof state -> renewal,
+					     0, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe,
 					     state -> options, oc);
@@ -2267,7 +2350,8 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 		if (option_cache_allocate (&oc, MDL)) {
 			if (make_const_data (&oc -> expression,
 					     (unsigned char *)&state -> rebind,
-					     sizeof state -> rebind, 0, 0)) {
+					     sizeof state -> rebind,
+					     0, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe,
 					     state -> options, oc);
@@ -2308,7 +2392,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 			if (make_const_data (&oc -> expression,
 					     lease -> subnet -> netmask.iabuf,
 					     lease -> subnet -> netmask.len,
-					     0, 0)) {
+					     0, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe,
 					     state -> options, oc);
@@ -2334,7 +2418,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 					     ((unsigned char *)
 					      lease -> host -> name),
 					     strlen (lease -> host -> name),
-					     1, 0)) {
+					     1, 0, MDL)) {
 				oc -> option = dhcp_universe.options [i];
 				save_option (&dhcp_universe,
 					     state -> options, oc);
@@ -2366,7 +2450,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 						     ((unsigned char *)
 						      h -> h_name),
 						     strlen (h -> h_name) + 1,
-						     1, 1)) {
+						     1, 1, MDL)) {
 					oc -> option =
 						dhcp_universe.options [i];
 					save_option (&dhcp_universe,
@@ -2394,7 +2478,7 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp)
 				if (make_const_data (&oc -> expression,
 						     lease -> ip_addr.iabuf,
 						     lease -> ip_addr.len,
-						     0, 0)) {
+						     0, 0, MDL)) {
 					oc -> option =
 						dhcp_universe.options [i];
 					save_option (&dhcp_universe,
@@ -2829,21 +2913,29 @@ int find_lease (struct lease **lp,
 		log_info ("trying next lease matching client id: %s",
 			  piaddr (uid_lease -> ip_addr));
 #endif
+
+#if defined (FAILOVER_PROTOCOL)
+		/* When failover is active, it's possible that there could
+		   be two "free" leases for the same uid, but only one of
+		   them that's available for this failover peer to allocate. */
+		if (uid_lease -> binding_state != FTS_ACTIVE &&
+		    !lease_mine_to_reallocate (uid_lease)) {
+#if defined (DEBUG_FIND_LEASE)
+			log_info ("not mine to allocate: %s",
+				  piaddr (uid_lease -> ip_addr));
+#endif
+			goto n_uid;
+		}
+#endif
+
 		if (uid_lease -> subnet -> shared_network != share) {
 #if defined (DEBUG_FIND_LEASE)
 			log_info ("wrong network segment: %s",
 				  piaddr (uid_lease -> ip_addr));
 #endif
-			if (uid_lease -> n_uid)
-				lease_reference (&next,
-						 uid_lease -> n_uid, MDL);
-			lease_dereference (&uid_lease, MDL);
-			if (next) {
-				lease_reference (&uid_lease, next, MDL);
-				lease_dereference (&next, MDL);
-			}
-			continue;
+			goto n_uid;
 		}
+
 		if ((uid_lease -> pool -> prohibit_list &&
 		     permitted (packet, uid_lease -> pool -> prohibit_list)) ||
 		    (uid_lease -> pool -> permit_list &&
@@ -2852,6 +2944,7 @@ int find_lease (struct lease **lp,
 			log_info ("not permitted: %s",
 				  piaddr (uid_lease -> ip_addr));
 #endif
+		       n_uid:
 			if (uid_lease -> n_uid)
 				lease_reference (&next,
 						 uid_lease -> n_uid, MDL);
@@ -2884,7 +2977,22 @@ int find_lease (struct lease **lp,
 		log_info ("trying next lease matching hw addr: %s",
 			  piaddr (hw_lease -> ip_addr));
 #endif
-		if (hw_lease -> ends >= cur_time &&
+#if defined (FAILOVER_PROTOCOL)
+		/* When failover is active, it's possible that there could
+		   be two "free" leases for the same uid, but only one of
+		   them that's available for this failover peer to allocate. */
+		if (hw_lease -> binding_state != FTS_ACTIVE &&
+		    !lease_mine_to_reallocate (hw_lease)) {
+#if defined (DEBUG_FIND_LEASE)
+			log_info ("not mine to allocate: %s",
+				  piaddr (hw_lease -> ip_addr));
+#endif
+			goto n_hw;
+		}
+#endif
+
+		if (hw_lease -> binding_state != FTS_FREE &&
+		    hw_lease -> binding_state != FTS_BACKUP &&
 		    hw_lease -> uid &&
 		    (!have_client_identifier ||
 		     hw_lease -> uid_len != client_identifier.len ||
@@ -2894,13 +3002,7 @@ int find_lease (struct lease **lp,
 			log_info ("wrong client identifier: %s",
 				  piaddr (hw_lease -> ip_addr));
 #endif
-			if (hw_lease -> n_hw)
-				lease_reference (&next, hw_lease -> n_hw, MDL);
-			lease_dereference (&hw_lease, MDL);
-			if (next) {
-				lease_reference (&hw_lease, next, MDL);
-				lease_dereference (&next, MDL);
-			}
+			goto n_hw;
 			continue;
 		}
 		if (hw_lease -> subnet -> shared_network != share) {
@@ -2908,13 +3010,7 @@ int find_lease (struct lease **lp,
 			log_info ("wrong network segment: %s",
 				  piaddr (hw_lease -> ip_addr));
 #endif
-			if (hw_lease -> n_hw)
-				lease_reference (&next, hw_lease -> n_hw, MDL);
-			lease_dereference (&hw_lease, MDL);
-			if (next) {
-				lease_reference (&hw_lease, next, MDL);
-				lease_dereference (&next, MDL);
-			}
+			goto n_hw;
 			continue;
 		}
 		if ((hw_lease -> pool -> prohibit_list &&
@@ -2925,10 +3021,11 @@ int find_lease (struct lease **lp,
 			log_info ("not permitted: %s",
 				  piaddr (hw_lease -> ip_addr));
 #endif
-			if (hw_lease -> n_hw)
-				lease_reference (&next, hw_lease -> n_hw, MDL);
 			if (!packet -> raw -> ciaddr.s_addr)
 				release_lease (hw_lease, packet);
+		       n_hw:
+			if (hw_lease -> n_hw)
+				lease_reference (&next, hw_lease -> n_hw, MDL);
 			lease_dereference (&hw_lease, MDL);
 			if (next) {
 				lease_reference (&hw_lease, next, MDL);
@@ -2995,15 +3092,11 @@ int find_lease (struct lease **lp,
 		      (unsigned)(ip_lease -> hardware_addr.hlen - 1))))) {
 		/* If we're not doing failover, the only state in which
 		   we can allocate this lease to the client is FTS_FREE.
-		   If we are doing failover, things are more complicated. */
-		if (
-#if !defined (FAILOVER_PROTOCOL)
-			(ip_lease -> binding_state != FTS_FREE &&
-			 ip_lease -> binding_state != FTS_BACKUP)
-#else
-			!lease_mine_to_reallocate (ip_lease)
-#endif
-			) {
+		   If we are doing failover, things are more complicated.
+		   If the lease is free or backup, we let the caller decide
+		   whether or not to give it out. */
+		if (ip_lease -> binding_state != FTS_FREE &&
+		    ip_lease -> binding_state != FTS_BACKUP) {
 #if defined (DEBUG_FIND_LEASE)
 			log_info ("rejecting lease for requested address.");
 #endif
@@ -3017,6 +3110,18 @@ int find_lease (struct lease **lp,
 				*allocatedp = 1;
 	}
 
+	/* If we got an ip_lease and a uid_lease or hw_lease, and ip_lease
+	   is not active, and is not ours to reallocate, forget about it. */
+	if (ip_lease && (uid_lease || hw_lease) &&
+	    ip_lease -> binding_state != FTS_ACTIVE &&
+	    !lease_mine_to_reallocate (ip_lease) &&
+	    packet -> packet_type == DHCPDISCOVER) {
+#if defined (DEBUG_FIND_LEASE)
+		log_info ("ip lease not ours to offer.");
+#endif
+		lease_dereference (&ip_lease, MDL);
+	}
+
 	/* If for some reason the client has more than one lease
 	   on the subnet that matches its uid, pick the one that
 	   it asked for and (if we can) free the other. */
@@ -3042,6 +3147,7 @@ int find_lease (struct lease **lp,
 				   it shouldn't still be using the old
 				   one, so we can free it for allocation. */
 				if (uid_lease &&
+				    uid_lease -> binding_state == FTS_ACTIVE &&
 				    !packet -> raw -> ciaddr.s_addr &&
 				    (share ==
 				     uid_lease -> subnet -> shared_network) &&
@@ -3195,7 +3301,8 @@ int find_lease (struct lease **lp,
 	if (uid_lease) {
 		if (lease) {
 			if (!packet -> raw -> ciaddr.s_addr &&
-			    packet -> packet_type == DHCPREQUEST)
+			    packet -> packet_type == DHCPREQUEST &&
+			    uid_lease -> binding_state == FTS_ACTIVE)
 				dissociate_lease (uid_lease);
 #if defined (DEBUG_FIND_LEASE)
 			log_info ("not choosing uid lease.");