diff -Nabur --exclude-from=exclude_files ospfd1.16/linux/ospfd_linux.C ospfd1.17/linux/ospfd_linux.C
--- ospfd1.16/linux/ospfd_linux.C	Wed Oct 11 10:44:07 2000
+++ ospfd1.17/linux/ospfd_linux.C	Thu Oct 12 13:41:46 2000
@@ -275,6 +275,9 @@
 	rtattr *rta;
 	int rta_len;
 	BSDPhyInt *phyp;
+	rtmsg *rtm;
+	InAddr net;
+	InMask mask;
       case RTM_NEWLINK:	// Interface flags change
 	ifinfo = (ifinfomsg *)NLMSG_DATA(msg);
 	syslog(LOG_NOTICE, "Ifc change IfIndex %d flags 0x%x",
@@ -307,6 +310,30 @@
 	syslog(LOG_NOTICE, "Interface addr change %s", inet_ntoa(in));
 	read_config();
 	break;
+      case RTM_DELROUTE:
+	rtm = (rtmsg *)NLMSG_DATA(msg);
+	if (rtm->rtm_protocol != PROT_OSPF)
+	    break;
+	rta_len = RTM_PAYLOAD(msg);
+	net = in.s_addr = 0;
+	mask = 0;
+	if (rtm->rtm_dst_len != 0) {
+	    for (rta = RTM_RTA(rtm); RTA_OK(rta, rta_len); 
+		 rta = RTA_NEXT(rta, rta_len)) {
+	        switch(rta->rta_type) {
+		  case RTA_DST:
+		    memcpy(&in.s_addr, RTA_DATA(rta), 4);
+		    break;
+		  default:
+		    break;
+		}
+	    }
+	    mask = ~((1 << (32-rtm->rtm_dst_len)) - 1);
+	    net = ntoh32(in.s_addr) & mask;
+	}
+	syslog(LOG_NOTICE, "Krt Delete %s", inet_ntoa(in));
+	ospf->krt_delete_notification(net, mask);
+	break;
       default:
 	break;
     }
@@ -405,7 +432,7 @@
     addr.nl_family = AF_NETLINK;
     addr.nl_pad = 0;
     addr.nl_pid = 0;
-    addr.nl_groups = (RTMGRP_LINK | RTMGRP_IPV4_IFADDR);
+    addr.nl_groups = (RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE);
     if (bind(rtsock, (sockaddr *)&addr, sizeof(addr)) < 0) {
 	syslog(LOG_ERR, "Failed to bind to rtnetlink socket: %m");
 	exit(1);
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/dbage.C ospfd1.17/src/dbage.C
--- ospfd1.16/src/dbage.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/dbage.C	Thu Oct 12 13:41:46 2000
@@ -126,6 +126,8 @@
     if (ospf->clear_mospf == true)
         ospf->mospf_clear_cache();
     // Process any pending LSA activity (flooding, origination)
+    // Synchronize with kernel
+    ospf->krt_sync();
 }
 
 /* Main aging routine called once a second. Increment the current
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/ospf.C ospfd1.17/src/ospf.C
--- ospfd1.16/src/ospf.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/ospf.C	Thu Oct 12 13:41:46 2000
@@ -172,6 +172,7 @@
     multicast_cache.clear();
     ospf_freepkt(&o_update);
     ospf_freepkt(&o_demand_upd);
+    krtdeletes.clear();
 
     // Reinitialize statics
     for (int i= 0; i < MaxAge+1; i++)
@@ -558,6 +559,25 @@
         phyp->operational = false;
 	phyp->verify_igmp_capabilities();
     }
+
+    // Delete phyint from routing table entries' next hops
+    INrte *rte;
+    INiterator rtiter(inrttbl);
+    while ((rte = rtiter.nextrte())) {
+        MPath *old;
+        if (!rte->valid())
+	    continue;
+	if (!rte->r_mpath)
+	    continue;
+	old = rte->r_mpath;
+	rte->r_mpath = old->prune_phyint(phyint);
+	if (!rte->r_mpath)
+	    rte->declare_unreachable();
+	if (rte->r_mpath != old) {
+	    rte->changed = true;
+	    rte->sys_install();
+	}
+    }
 }
 
 /* An indication that the physical and data link layers
@@ -566,6 +586,11 @@
  * Redo the external routing calculation in case the
  * physical interface contains non-OSPF subnets which
  * are referenced in imported external routes.
+ *
+ * In additional, force a routing calculation because a
+ * previous phy_down() deleted routing table entries, and
+ * if LSAs have not changed (say because of a quick link
+ * flap) we need to put them back.
  */
 
 
@@ -577,8 +602,11 @@
 
     ase_sched = true;
     while ((ip = iter.get_next())) {
-	if (ip->if_phyint == phyint)
+        if (ip->if_phyint == phyint) {
 	    ip->run_fsm(IFE_UP);
+	    full_sched = true;
+	    ase_sched = true;
+	}
     }
 }
 
@@ -637,6 +665,25 @@
 	}
     }
     delete gentry;
+}
+
+/* Kernel has indicated that it has deleted one of the
+ * routes that we have added. This is probably due to
+ * a network interface going down. Store the information
+ * so that if we don't soon delete the entry also, we
+ * will re-add it to the kernel in OSPF::krt_sync().
+ */
+
+void OSPF::krt_delete_notification(InAddr net, InMask mask)
+
+{
+    INrte *rte;
+
+    if ((rte = inrttbl->find(net, mask)) && rte->valid()) {
+        KrtSync *item;
+	item = new KrtSync(net, mask);
+	krtdeletes.add(item);
+    }
 }
 
 /* Perform a lookup in OSPF's copy of the IP routing
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/ospf.h ospfd1.17/src/ospf.h
--- ospfd1.16/src/ospf.h	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/ospf.h	Thu Oct 12 13:41:46 2000
@@ -83,6 +83,7 @@
     int	countdown;	// Number of seconds before exit
     bool delete_neighbors; // Neighbors being deleted?
     AVLtree phyints;	// Physical interfaces
+    AVLtree krtdeletes;	// Deleted, unsynced kernel routing entries
     // Flooding queues
     int	n_local_flooded;// AS-external-LSAs originated this tick
     ExRtData *ases_pending; // Pending AS-external-LSA originations
@@ -230,6 +231,7 @@
     void update_area_ranges(INrte *rte);
     void advertise_ranges();
     void do_all_ases();
+    void krt_sync();
     
     // MOSPF routines
     INrte *mc_source(InAddr src);
@@ -258,7 +260,7 @@
     // Version numbers
     enum {
 	vmajor = 1,	// Major version number
-	vminor = 16,	// Minor version number
+	vminor = 17,	// Minor version number
     };
 
     // Entry points into the OSPF code
@@ -274,6 +276,7 @@
     void leave_indication(InAddr group, int phyint);
     void phy_up(int phyint);
     void phy_down(int phyint);
+    void krt_delete_notification(InAddr net, InMask mask);
     MPath *ip_lookup(InAddr dest);
     InAddr ip_source(InAddr dest);
     InAddr if_addr(int phyint);
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/rte.C ospfd1.17/src/rte.C
--- ospfd1.16/src/rte.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/rte.C	Thu Oct 12 13:41:46 2000
@@ -21,6 +21,7 @@
  */
 
 #include "ospfinc.h"
+#include "ifcfsm.h"
 
 /* Display strings for the various routing table types.
  * Must match the enum defining RT_SPF, etc.
@@ -52,7 +53,7 @@
 {
     NH paths[MAXPATH];
 
-    if (ip->is_virtual())
+    if (ip->is_virtual() || ip->state() == IFS_DOWN)
 	return(0);
     paths[0].if_addr = ip->if_addr;
     paths[0].phyint = ip->if_phyint;
@@ -143,6 +144,8 @@
     int i, j;
     int n_paths = mp->npaths;
 
+    if (!mp)
+        return(0);
     for (i = 0, j = 0; i < mp->npaths; i++, j++) {
 	SpfIfc *ip;
 	paths[j] = mp->NHs[i];
@@ -175,6 +178,43 @@
     return(modified ? create(n_paths, paths) : mp);
 }
 
+/* Prune all the next hops going over a particular phyint
+ * from a multipath entry. This is done when a physical
+ * interface becomes inoperational. If all next hops are
+ * pruned, 0 is returned.
+ */
+
+MPath *MPath::prune_phyint(int phyint)
+
+{
+    bool modified=false;
+    NH paths[MAXPATH];
+    int i, j;
+
+    // Previously cached result?
+    if (phyint == pruned_phyint)
+        return(pruned_mpath);
+
+    // Remove next hops referencing phyint
+    for (i = 0, j = 0; i < npaths; i++) {
+        if (NHs[i].phyint == phyint) {
+	    modified = true;
+	    continue;
+	}
+	paths[j++] = NHs[i];
+    }
+
+    pruned_phyint = phyint;
+    if (j == 0)
+        pruned_mpath = 0;
+    else if (!modified)
+        pruned_mpath = this;
+    else
+        pruned_mpath = create(j, paths);
+
+    return(pruned_mpath);
+}
+
 /* Look for an entry in the multipath database. If it's not
  * already there, create it and add to the database.
  * Argument assumed to be an array of size MAXPATH.
@@ -203,6 +243,8 @@
     entry->npaths = n_paths;
     for (i = 0; i < MAXPATH; i++)
 	entry->NHs[i] = paths[i];
+    entry->pruned_phyint = -1;
+    entry->pruned_mpath = 0;
     // Add to database
     entry->key = (byte *) entry->NHs;
     entry->keylen = len;
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/rte.h ospfd1.17/src/rte.h
--- ospfd1.16/src/rte.h	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/rte.h	Thu Oct 12 13:41:46 2000
@@ -36,12 +36,15 @@
   public:
     int	npaths;
     NH	NHs[MAXPATH];
+    int pruned_phyint;
+    MPath *pruned_mpath;
     static PatTree nhdb;
     static MPath *create(int, NH *);
     static MPath *create(SpfIfc *, InAddr);
     static MPath *create(int, InAddr);
     static MPath *merge(MPath *, MPath *);
     static MPath *addgw(MPath *, InAddr);
+    MPath *prune_phyint(int phyint);
     bool all_in_area(class SpfArea *);
 };	
 
@@ -421,3 +424,15 @@
 {
     return(index1());
 }
+
+/* Data structure used to store differences between the
+ * kernel routing table and OSPF's. Time is when the
+ * kernel has reported a deletion that we didn't know
+ * about.
+ */
+
+class KrtSync : public AVLitem {
+  public:
+    SPFtime tstamp;
+    KrtSync(InAddr net, InMask mask);
+};
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/spfcalc.C ospfd1.17/src/spfcalc.C
--- ospfd1.16/src/spfcalc.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/spfcalc.C	Thu Oct 12 13:41:46 2000
@@ -624,8 +624,15 @@
 void INrte::sys_install()
 
 {
+    AVLitem *item;
     int msgno;
 
+    // We're about to synchronize with the kernel
+    if ((item = ospf->krtdeletes.find(net(), mask()))) {
+        ospf->krtdeletes.remove(item);
+	delete item;
+    }
+
     switch(r_type) {
       case RT_NONE:
 	msgno = LOG_DELRT;
@@ -665,6 +672,52 @@
         ase_orig = false;
 	ospf->ase_orig(this, 0);
     }
+}
+
+/* Resynchronize the routing table by re-adding routes that
+ * the kernel deleted fror some unknown reason.
+ */
+
+void OSPF::krt_sync()
+
+{
+    AVLsearch iter(&krtdeletes);
+    KrtSync *item;
+
+    if (shutting_down())
+        return;
+
+    while ((item = (KrtSync *)iter.next())) {
+        InAddr net;
+	InMask mask;
+	INrte *rte;
+	if (time_diff(sys_etime, item->tstamp) < 5*Timer::SECOND)
+	    continue;
+	net = item->index1();
+	mask = item->index2();
+	krtdeletes.remove(item);
+	delete item;
+	rte = inrttbl->find(net, mask);
+	if (!rte || !rte->valid())
+	    continue;
+	if (ospf->spflog(LOG_KRTSYNC, 5))
+	    ospf->log(rte);
+	sys->rtadd(net, mask, rte->r_mpath, rte->last_mpath, 
+		   rte->r_type == RT_REJECT);
+    }
+}
+
+/* When we construct the entry indicating that the
+ * kernel deleted a route before we did, note the
+ * time so that we can wait long enough to know whether
+ * we should re-add it. Must wait until an updated LSA
+ * is reissued and the routing calculation is rerun.
+ */
+
+KrtSync::KrtSync(InAddr net, InMask mask) : AVLitem(net, mask)
+
+{
+    tstamp = sys_etime;
 }
 
 /* (Re)resolve the reachability and cost of all forwarding
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/spflog.h ospfd1.17/src/spflog.h
--- ospfd1.16/src/spflog.h	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/spflog.h	Thu Oct 12 13:41:46 2000
@@ -82,6 +82,7 @@
     LOG_GRPEXP,		// Group expired
     IGMP_RCV,		// Received IGMP packet
     LOG_SPFDEBUG,	// Debug statements
+    LOG_KRTSYNC,	// Synch kernel routing entry
     MAXLOG,		// KEEP THIS LAST!!!!
 };
 
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/spfutil.C ospfd1.17/src/spfutil.C
--- ospfd1.16/src/spfutil.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/spfutil.C	Thu Oct 12 13:41:46 2000
@@ -406,6 +406,8 @@
 	return("Received IGMP packet, type");
       case LOG_SPFDEBUG:
 	return("DEBUG");
+      case LOG_KRTSYNC:
+	return("Synching kernel routing entry");
       default:
 	break;
     }
diff -Nabur --exclude-from=exclude_files ospfd1.16/src/summlsa.C ospfd1.17/src/summlsa.C
--- ospfd1.16/src/summlsa.C	Wed Oct 11 10:44:06 2000
+++ ospfd1.17/src/summlsa.C	Thu Oct 12 13:41:46 2000
@@ -363,8 +363,6 @@
     if (new_type == RT_NONE &&
 	(r_type == RT_SPFIA || r_type == RT_REJECT)) {
 	declare_unreachable();
-	sys->rtdel(net(), mask(), last_mpath);
-	last_mpath = 0;
 	changed = true;
 	return;
     }

.