Generalize fallback interface code so it can work on Linux.

Don't reclaim an abandoned lease if there's an available lease
that expired more recently but was not abandoned.

diff --git a/server/dhcp.c b/server/dhcp.c
index 48fc56e62ff4fe549d1e68969fb861a57994c8ac..d1d4e465e70c211c10e328b6c6fca533e23eb784 100644 (file)
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -42,7 +42,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: dhcp.c,v 1.57.2.11 1998/11/24 23:12:39 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: dhcp.c,v 1.57.2.12 1998/12/20 17:53:02 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -120,9 +120,25 @@ void dhcpdiscover (packet)
                   warning message, so that if it continues to lose,
                   the administrator will eventually investigate. */
                if (lease -> flags & ABANDONED_LEASE) {
-                       warn ("Reclaiming abandoned IP address %s.",
-                             piaddr (lease -> ip_addr));
-                       lease -> flags &= ~ABANDONED_LEASE;
+                       struct lease *lp;
+
+                       /* See if we can find an unabandoned lease first. */
+                       for (lp = lease; lp; lp = lp -> prev) {
+                               if (lp -> ends > cur_time)
+                                       break;
+                               if (!lp -> flags & ABANDONED_LEASE) {
+                                       lease = lp;
+                                       break;
+                               }
+                       }
+
+                       /* If we can't find an unabandoned lease, reclaim the
+                          abandoned lease. */
+                       if (lease -> flags & ABANDONED_LEASE) {
+                               warn ("Reclaiming abandoned IP address %s.",
+                                     piaddr (lease -> ip_addr));
+                               lease -> flags &= ~ABANDONED_LEASE;
+                       }
                }
 
                /* Try to find a host_decl that matches the client
@@ -501,14 +517,15 @@ void nak_lease (packet, cip)
                to.sin_addr = raw.giaddr;
                to.sin_port = local_port;
 
-#ifdef USE_FALLBACK
-               result = send_fallback (&fallback_interface,
-                                       packet, &raw, outgoing.packet_length,
-                                       from, &to, &hto);
-               if (result < 0)
-                       warn ("send_fallback: %m");
-               return;
-#endif
+               if (fallback_interface) {
+                       result = send_packet (fallback_interface,
+                                             packet, &raw,
+                                             outgoing.packet_length,
+                                             from, &to, &hto);
+                       if (result < 0)
+                               warn ("send_fallback: %m");
+                       return;
+               }
        } else {
                to.sin_addr.s_addr = htonl (INADDR_BROADCAST);
                to.sin_port = remote_port;
@@ -1131,41 +1148,41 @@ void dhcp_reply (lease)
                to.sin_addr = raw.giaddr;
                to.sin_port = local_port;
 
-#ifdef USE_FALLBACK
-               result = send_fallback (&fallback_interface,
-                                       (struct packet *)0,
-                                       &raw, packet_length,
-                                       raw.siaddr, &to, &hto);
-               if (result < 0)
-                       warn ("send_fallback: %m");
+               if (fallback_interface) {
+                       result = send_packet (fallback_interface,
+                                             (struct packet *)0,
+                                             &raw, packet_length,
+                                             raw.siaddr, &to, &hto);
+                       if (result < 0)
+                               warn ("send_fallback: %m");
 
-               free_lease_state (state, "dhcp_reply fallback 1");
-               lease -> state = (struct lease_state *)0;
-               return;
-#endif
+                       free_lease_state (state, "dhcp_reply fallback 1");
+                       lease -> state = (struct lease_state *)0;
+                       return;
+               }
 
-       /* If it comes from a client who already knows its address and
+       /* If it comes from a client that already knows its address and
           is not requesting a broadcast response, sent it directly to
           that client. */
        } else if (raw.ciaddr.s_addr && state -> offer == DHCPACK &&
-                  !(raw.flags & htons (BOOTP_BROADCAST))) {
+                  !(raw.flags & htons (BOOTP_BROADCAST)) &&
+                  can_unicast_without_arp ()) {
                to.sin_addr = state -> ciaddr;
                to.sin_port = remote_port; /* XXX */
 
-#ifdef USE_FALLBACK
-               result = send_fallback (&fallback_interface,
-                                       (struct packet *)0,
-                                       &raw, packet_length,
-                                       raw.siaddr, &to, &hto);
-               if (result < 0)
-                       warn ("send_fallback: %m");
-               free_lease_state (state, "dhcp_reply fallback 1");
-               lease -> state = (struct lease_state *)0;
-               return;
-#endif
-
-       /* Otherwise, broadcast it on the local network. */
+               if (fallback_interface) {
+                       result = send_packet (fallback_interface,
+                                             (struct packet *)0,
+                                             &raw, packet_length,
+                                             raw.siaddr, &to, &hto);
+                       if (result < 0)
+                               warn ("send_fallback: %m");
+                       free_lease_state (state, "dhcp_reply fallback 1");
+                       lease -> state = (struct lease_state *)0;
+                       return;
+               }
        } else {
+               /* Otherwise, broadcast it on the local network. */
                to.sin_addr.s_addr = htonl (INADDR_BROADCAST);
                to.sin_port = remote_port; /* XXX */
        }