From: Ondrej Zajicek (work) <santiago@crfreenet.org>
Date: Sun, 3 Feb 2019 16:31:27 +0000 (+0100)
Subject: OSPF: Reject duplicate DBDES packets after dead interval
X-Git-Tag: v2.0.4~13
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=16605f2fdad730b8bb570e17192dc5f45cf15d3f;p=thirdparty%2Fbird.git

OSPF: Reject duplicate DBDES packets after dead interval

Master may free last DBDES packet immediately. Slave must wait dead
interval before freeing last DBDES packet and then reject duplicate
DBDES packets with SeqNumberMismatch.
---

diff --git a/proto/ospf/dbdes.c b/proto/ospf/dbdes.c
index 4d3bbe8c2..a1559782a 100644
--- a/proto/ospf/dbdes.c
+++ b/proto/ospf/dbdes.c
@@ -238,6 +238,14 @@ ospf_rxmt_dbdes(struct ospf_proto *p, struct ospf_neighbor *n)
   ospf_do_send_dbdes(p, n);
 }
 
+void
+ospf_reset_ldd(struct ospf_proto *p UNUSED, struct ospf_neighbor *n)
+{
+  mb_free(n->ldd_buffer);
+  n->ldd_buffer = NULL;
+  n->ldd_bsize = 0;
+}
+
 static int
 ospf_process_dbdes(struct ospf_proto *p, struct ospf_packet *pkt, struct ospf_neighbor *n)
 {
@@ -434,6 +442,7 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
       if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))
       {
 	tm_stop(n->dbdes_timer);
+	ospf_reset_ldd(p, n);
 	ospf_neigh_sm(n, INM_EXDONE);
 	break;
       }
@@ -457,7 +466,11 @@ ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa,
       ospf_send_dbdes(p, n);
 
       if (!(n->myimms & DBDES_M) && !(n->imms & DBDES_M))
+      {
+	/* Use dbdes timer to postpone freeing of Last DBDES packet buffer */
+	tm_start(n->dbdes_timer, n->ifa->deadint S);
 	ospf_neigh_sm(n, INM_EXDONE);
+      }
     }
     break;
 
diff --git a/proto/ospf/neighbor.c b/proto/ospf/neighbor.c
index 54d643c65..c143b1306 100644
--- a/proto/ospf/neighbor.c
+++ b/proto/ospf/neighbor.c
@@ -608,6 +608,12 @@ dbdes_timer_hook(timer *t)
 
   if ((n->state == NEIGHBOR_EXCHANGE) && (n->myimms & DBDES_MS))
     ospf_rxmt_dbdes(p, n);
+
+  if ((n->state > NEIGHBOR_LOADING) && !(n->myimms & DBDES_MS))
+  {
+    ospf_reset_ldd(p, n);
+    tm_stop(n->dbdes_timer);
+  }
 }
 
 static void
diff --git a/proto/ospf/ospf.h b/proto/ospf/ospf.h
index 23289ccd5..d3f127389 100644
--- a/proto/ospf/ospf.h
+++ b/proto/ospf/ospf.h
@@ -1041,6 +1041,7 @@ uint ospf_hello3_options(struct ospf_packet *pkt);
 /* dbdes.c */
 void ospf_send_dbdes(struct ospf_proto *p, struct ospf_neighbor *n);
 void ospf_rxmt_dbdes(struct ospf_proto *p, struct ospf_neighbor *n);
+void ospf_reset_ldd(struct ospf_proto *p, struct ospf_neighbor *n);
 void ospf_receive_dbdes(struct ospf_packet *pkt, struct ospf_iface *ifa, struct ospf_neighbor *n);
 uint ospf_dbdes3_options(struct ospf_packet *pkt);