diff -X exclude_files -Nabur ospfd2.13/ospf_sim/ospfd_sim.h ospfd2.14/ospf_sim/ospfd_sim.h
--- ospfd2.13/ospf_sim/ospfd_sim.h	Tue Nov 20 13:33:02 2001
+++ ospfd2.14/ospf_sim/ospfd_sim.h	Fri Feb 15 10:29:28 2002
@@ -95,8 +95,6 @@
     bool hitless_preparation;
     bool hitless_preparation_complete;
     SPFtime grace_period;
-    int n_md5;
-    MD5Seq *snarray;
   public:
     SimSys(int fd);
     ~SimSys();
diff -X exclude_files -Nabur ospfd2.13/ospf_sim/sim_system.C ospfd2.14/ospf_sim/sim_system.C
--- ospfd2.13/ospf_sim/sim_system.C	Tue Nov 20 13:33:02 2001
+++ ospfd2.14/ospf_sim/sim_system.C	Fri Feb 15 10:29:28 2002
@@ -327,10 +327,6 @@
 
 {
     time_add(sys_etime, period*Timer::SECOND, &grace_period);
-    delete snarray;
-    snarray = new MD5Seq[n];
-    n_md5 = n;
-    memcpy(snarray, sns, n*sizeof(MD5Seq));
     hitless_preparation = true;
 }
 
diff -X exclude_files -Nabur ospfd2.13/src/helper.C ospfd2.14/src/helper.C
--- ospfd2.13/src/helper.C	Tue Nov 20 13:32:59 2001
+++ ospfd2.14/src/helper.C	Fri Feb 15 10:29:23 2002
@@ -75,9 +75,7 @@
 
 {
     SpfNbr *np;
-    SPFtime grace_start;
     int grace_period;
-    SPFtime grace_end;
     char *refusal = 0;
 
     // Ignore our own
@@ -85,23 +83,28 @@
         return;
     if (!(np = lsap->grace_lsa_parse((byte *)(hdr+1),
 				     ntoh16(hdr->ls_length)-sizeof(LShdr),
-				     grace_start, grace_period)))
+				     grace_period)))
         return;
 
     // Have associated grace-LSA with a neighbor
     if (spflog(LOG_GRACERX, 5))
         log(np);
+    // If we are going to cancel some help sessions, do it now
+    if (topology_change)
+        htl_topology_change();
 
     // Now determine whether we should accept it
-    time_add(grace_start, grace_period*Timer::SECOND, &grace_end);
+    // Skip these checks if already helping
+    if (!np->we_are_helping()) {
     // Neighbor must be in Full state
     if (np->n_state != NBS_FULL)
         refusal = "Not full";
     // No topology changes since grace period start
-    else if (time_less(grace_start, last_topology_change))
+	else if (np->changes_pending())
         refusal = "Topology change";
+    }
     // Grace period already expired?
-    else if (time_less(grace_end, sys_etime))
+    if (refusal == 0 && grace_period <= 0)
         refusal = "Timeout";
 
     /* If we are refusing the grace request, either exit
@@ -124,10 +127,12 @@
         if (np->we_are_helping()) {
 	    np->n_helptim.stop();
 	    np->n_ifp->if_helping--;
+	    np->n_ifp->area()->a_helping--;
 	    n_helping--;
 	}
 	np->n_helptim.start(grace_period*Timer::SECOND, false);
 	np->n_ifp->if_helping++;
+	np->n_ifp->area()->a_helping++;
 	n_helping++;
     }
 }
@@ -141,7 +146,6 @@
 
 {
     SpfNbr *np;
-    SPFtime grace_start;
     int grace_period;
 
     // Ignore our own
@@ -149,20 +153,19 @@
         return;
     if (!(np = lsap->grace_lsa_parse(lsap->lsa_body,
 				     lsap->lsa_length - sizeof(LShdr),
-				     grace_start, grace_period)))
+				     grace_period)))
         return;
     // Exit helper mode
     if (np->we_are_helping())
         np->exit_helper_mode("Success");
 }
 
-/* Parse the body of a grace-LSA, determing a) the start of the
- * requested grace period, b) the end, and c) the neighbor requesting
+/* Parse the body of a grace-LSA, determing a) the length of the
+ * requested grace period (from now) and b) the neighbor requesting
  * grace.
  */
 
-SpfNbr *opqLSA::grace_lsa_parse(byte *body, int len, 
-				SPFtime &g_start, int &g_period)
+SpfNbr *opqLSA::grace_lsa_parse(byte *body, int len, int &g_period)
 
 {
     TLVbuf buf(body, len);
@@ -170,16 +173,6 @@
     InAddr nbr_addr = 0;
     int32 val;
 
-    // Start of grace period determined by LS age
-    if (sys_etime.sec < lsa_age()) {
-        g_start.sec = 0;
-	g_start.msec = 0;
-    }
-    else {
-        g_start.sec = sys_etime.sec - lsa_age();
-	g_start.msec = sys_etime.msec;
-    }
-
     // Parse body of grace-LSA
     g_period = 0;
     while (buf.next_tlv(type)) {
@@ -200,6 +193,7 @@
 	}
     };
 
+    g_period -= (int) lsa_age();
     return(lsa_ifp->find_nbr(nbr_addr, adv_rtr()));
 }
 
@@ -220,6 +214,7 @@
     }
     n_helptim.stop();
     n_ifp->if_helping--;
+    n_ifp->area()->a_helping--;
     ospf->n_helping--;
     /* If neighbor is not yet full again, do the
      * processing that should have been done when the
@@ -247,6 +242,42 @@
     }
 }
 
+/* Determine whether a changed LSA should terminate
+ * helping sessions in one or more areas. If so,
+ * set SpfArea::cancel_help_sessions, and the sessions
+ * will be cancelled at the next timer tick. We don't
+ * cancel the sessions in this routine to avoid recursive
+ * updates of the link-state database.
+ */
+
+void OSPF::cancel_help_sessions(LSA *lsap)
+
+{
+    SpfArea *ap;
+
+    if (n_helping == 0)
+        return;
+    // Only LS types 1-5 are significant for hitless restart
+    if (lsap->lsa_type > LST_ASL)
+        return;
+    // Area-scoped change
+    else if (lsap->lsa_type < LST_ASL) {
+	ap = lsap->lsa_ap;
+	if ((ap->cancel_help_sessions = (ap->a_helping != 0)))
+	    topology_change = true;;
+    }
+    // Global-scoped change
+    else {
+        AreaIterator iter(this);
+	while ((ap = iter.get_next())) {
+	    if (ap->is_stub())
+	        continue;
+	    if ((ap->cancel_help_sessions = (ap->a_helping != 0)))
+	        topology_change = true;;
+	}
+    }
+}
+
 /* A topology change has occurred. Cancel all helping modes,
  * and reoriginate router-LSAs, network-LSAs and rerun
  * Designated Router calculations, as necessary.
@@ -258,19 +289,21 @@
 void OSPF::htl_topology_change()
 
 {
-    // clear topolog change flag
+    AreaIterator a_iter(this);
+    SpfArea *ap;
+
     topology_change = false;
-    // Update time of last topology change
-    last_topology_change = sys_etime;
     // Cancel any helping sessions
-    if (n_helping != 0) {
-        IfcIterator iiter(this);
+    while ((ap = a_iter.get_next())) {
+        if (!ap->cancel_help_sessions)
+	    continue;
+	IfcIterator iiter(ap);
 	SpfIfc *ip;
 	while ((ip = iiter.get_next())) {
-	    NbrIterator niter(ip);
-	    SpfNbr *np;
 	    if (ip->if_helping == 0)
 	        continue;
+	    NbrIterator niter(ip);
+	    SpfNbr *np;
 	    while ((np = niter.get_next()))
 	        if (np->we_are_helping())
 		    np->exit_helper_mode("Topology change", false);
@@ -279,7 +312,8 @@
 	    // Reoriginate network-LSA
 	    ip->nl_orig(false);
 	}
+	ap->cancel_help_sessions = false;
+    }
 	// Re-originate all router-LSAs
 	rl_orig();
-    }
 }
diff -X exclude_files -Nabur ospfd2.13/src/lsdb.C ospfd2.14/src/lsdb.C
--- ospfd2.13/src/lsdb.C	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/lsdb.C	Fri Feb 15 10:29:22 2002
@@ -259,9 +259,7 @@
     // If changes, schedule new routing calculations
     if (changed) {
 	rtsched(lsap, old_rte);
-	// Only LS types 1-5 are significant for hitless restart
-	if (lsap->lsa_type <= LST_ASL)
-	    topology_change = true;
+	cancel_help_sessions(lsap);
 	if (in_hitless_restart())
 	    htl_check_consistency(ap, hdr);
     }
diff -X exclude_files -Nabur ospfd2.13/src/opqlsa.h ospfd2.14/src/opqlsa.h
--- ospfd2.13/src/opqlsa.h	Tue Nov 20 13:32:59 2001
+++ ospfd2.14/src/opqlsa.h	Fri Feb 15 10:29:23 2002
@@ -42,7 +42,7 @@
     virtual void unparse();
     virtual void build(LShdr *hdr);
     virtual void update_in_place(LSA *);
-    SpfNbr *grace_lsa_parse(byte *, int, SPFtime &, int &);
+    SpfNbr *grace_lsa_parse(byte *, int, int &);
     friend class OSPF;
 };
 
diff -X exclude_files -Nabur ospfd2.13/src/ospf.C ospfd2.14/src/ospf.C
--- ospfd2.13/src/ospf.C	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/ospf.C	Fri Feb 15 10:29:22 2002
@@ -119,7 +119,6 @@
     htl_exit_reason = 0;
     topology_change = false;
     start_time = sys_etime;
-    last_topology_change = sys_etime;
     n_helping = 0;
 
     n_dijkstras = 0;
diff -X exclude_files -Nabur ospfd2.13/src/ospf.h ospfd2.14/src/ospf.h
--- ospfd2.13/src/ospf.h	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/ospf.h	Fri Feb 15 10:29:22 2002
@@ -167,7 +167,6 @@
     // Helper variables
     bool topology_change;
     SPFtime start_time;
-    SPFtime last_topology_change;
     int n_helping;	// # neighbors being helped
 
     // Monitoring routines
@@ -303,6 +302,7 @@
     void grace_LSA_rx(class opqLSA *, LShdr *);
     void grace_LSA_flushed(class opqLSA *);
     void htl_topology_change();
+    void cancel_help_sessions(LSA *lsap);
     // While restarting hitlessly
     bool in_hitless_restart();
     void htl_exit_criteria();
@@ -329,7 +329,7 @@
     // Version numbers
     enum {
 	vmajor = 2,	// Major version number
-	vminor = 13,	// Minor version number
+	vminor = 14,	// Minor version number
     };
 
     // Entry points into the OSPF code
diff -X exclude_files -Nabur ospfd2.13/src/spfack.C ospfd2.14/src/spfack.C
--- ospfd2.13/src/spfack.C	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/spfack.C	Fri Feb 15 10:29:22 2002
@@ -343,3 +343,34 @@
 {
     ip->if_send_dack();
 }
+
+/* Look through retransmission list to see if any real
+ * changes are pending to the neighbor (periodic refreshes
+ * don't count). This is used to evaluate whether we should
+ * help a neighbor requesting a hitless restart.
+ */
+
+bool SpfNbr::changes_pending()
+
+{
+    LsaListIterator iter1(&n_pend_rxl);
+    LsaListIterator iter2(&n_rxlst);
+    LsaListIterator iter3(&n_failed_rxl);
+    LSA *lsap;
+
+    while ((lsap = iter1.get_next())) {
+        if (lsap->valid() && lsap->changed)
+	    return(true);
+    }
+    while ((lsap = iter2.get_next())) {
+        if (lsap->valid() && lsap->changed)
+	    return(true);
+    }
+    while ((lsap = iter3.get_next())) {
+        if (lsap->valid() && lsap->changed)
+	    return(true);
+    }
+
+    return(false);
+}
+
diff -X exclude_files -Nabur ospfd2.13/src/spfarea.C ospfd2.14/src/spfarea.C
--- ospfd2.13/src/spfarea.C	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/spfarea.C	Fri Feb 15 10:29:22 2002
@@ -59,6 +59,8 @@
     size_mospf_incoming = 0;
     mospf_in_phys = 0;
     mospf_in_count = 0;
+    a_helping = 0;
+    cancel_help_sessions = false;
 }
 
 /* Find an area data structure, given its Area ID.
diff -X exclude_files -Nabur ospfd2.13/src/spfarea.h ospfd2.14/src/spfarea.h
--- ospfd2.13/src/spfarea.h	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/spfarea.h	Fri Feb 15 10:29:22 2002
@@ -56,6 +56,9 @@
     int size_mospf_incoming; // Size of incoming interface array
     int *mospf_in_phys; // Incoming phyints
     int mospf_in_count; // Number of same;
+    // Hitless restart parameters
+    int a_helping;	// # neighbors being helped in area
+    bool cancel_help_sessions; // should we cancel helping sessions?
 
     AVLtree abr_tbl;	// RTRrte's for area border routers
     AVLtree AdjAggr;	// Aggregate adjacency information
diff -X exclude_files -Nabur ospfd2.13/src/spfnbr.h ospfd2.14/src/spfnbr.h
--- ospfd2.13/src/spfnbr.h	Tue Nov 20 13:32:58 2001
+++ ospfd2.14/src/spfnbr.h	Fri Feb 15 10:29:22 2002
@@ -211,6 +211,7 @@
     bool remove_from_pending_rxmt(LSA *lsap);
     LSA	*get_next_rxmt(LsaList * &list, uns32 &nexttime);
     void clear_rxmt_list();
+    bool changes_pending();
 
     // Packet reception functions
     void recv_dd(Pkt *pdesc);

.