* Upon local mpls ecmp label deallocation, control-node would withdraw

  this mpls label in its path, if the label gets reused even before
  control-node retracts the label, due to quick activate and deactivate
  of the interface(oper state change), then mpls label in BGP path would
  point to internface NH, instead of composite NH as expected.
  Re-evaluation of BGP peer happens because it was one of the ecmp interface
  that got deactivated and added again.
  Add a check to verify that local ecmp mpls label is not deleted.
Unit test:
  Created ecmp with 2 instances, add the same route with aggregarte mpls
  label via bgp peer, deleted both interface so that route update is
  sent to BGP to withdraw this path, before BGP peer could withdraw
  same instance would be activated with aggregarate mpls label and
  route change would be triggered, verify that no crash is seen,
  and update of path happens fine
Closes-bug:#1381821

Change-Id: I27a0f8ca0f011cc4bab3de79787356d32563c4d6

src/vnsw/agent/oper/agent_path.cc

@@ -218,7 +218,8 @@ bool AgentPath::Sync(AgentRoute *sync_route) {
 
     //Check if there was a change in local ecmp composite nexthop
     if (nh_ && nh_->GetType() == NextHop::COMPOSITE &&
-        composite_nh_key_.get() != NULL) {
+        composite_nh_key_.get() != NULL &&
+        local_ecmp_mpls_label_.get() != NULL) {
         boost::scoped_ptr<CompositeNHKey> composite_nh_key(composite_nh_key_->Clone());
         if (ReorderCompositeNH(agent, composite_nh_key.get())) {
             if (ChangeCompositeNH(agent, composite_nh_key.get())) {

src/vnsw/agent/pkt/test/test_ecmp.cc

@@ -49,6 +49,7 @@ class EcmpTest : public ::testing::Test {
         boost::system::error_code ec;
         bgp_peer = CreateBgpPeer(Ip4Address::from_string("0.0.0.1", ec),
                                  "xmpp channel");
+        client->WaitForIdle();
 
         //Add floating IP for vrf2 interface to talk to
         //vrf3
@@ -1487,7 +1488,8 @@ TEST_F(EcmpTest, ServiceVlanTest_3) {
     DeleteVmportEnv(input1, 1, true);
     client->WaitForIdle();
 
-    EXPECT_TRUE(Agent::GetInstance()->pkt()->flow_table()->Size() == 0);
+    WAIT_FOR(1000, 1000,
+            (Agent::GetInstance()->pkt()->flow_table()->Size() == 0));
     EXPECT_FALSE(VrfFind("vrf11"));
     EXPECT_FALSE(VrfFind("vrf10"));
     EXPECT_FALSE(VrfFind("service-vrf1"));

src/vnsw/agent/test/test_nh.cc

@@ -2241,6 +2241,71 @@ TEST_F(CfgTest, Nexthop_invalid_vrf) {
     WAIT_FOR(1000, 1000, (VrfGet("vrf11") == NULL));
 }
 
+//Delete local ecmp mpls label by
+//deleting all local interfaces, add them
+//back with BGP path still retaining old local ecmp
+//mpls and ensure there is no crash
+TEST_F(CfgTest, EcmpNH_18) {
+    //Add interface
+    struct PortInfo input[] = {
+        {"vnet1", 1, "1.1.1.1", "00:00:00:01:01:01", 1, 1},
+        {"vnet2", 2, "1.1.1.1", "00:00:00:01:01:01", 1, 2},
+    };
+    CreateVmportWithEcmp(input, 2);
+    client->WaitForIdle();
+
+    Ip4Address ip = Ip4Address::from_string("1.1.1.1");
+    InetUnicastRouteEntry *rt = RouteGet("vrf1", ip, 32);
+    EXPECT_TRUE(rt != NULL);
+    const NextHop *nh = rt->GetActiveNextHop();
+
+    //Create component NH list
+    //Transition remote VM route to ECMP route
+    DBEntryBase::KeyPtr key = nh->GetDBRequestKey();
+    NextHopKey *nh_key = static_cast<NextHopKey *>(key.release());
+    std::auto_ptr<const NextHopKey> nh_akey(nh_key);
+    ComponentNHKeyPtr nh_data1(new ComponentNHKey(rt->GetActiveLabel(), nh_akey));
+
+    uint32_t label = rt->GetActiveLabel();
+    ComponentNHKeyList comp_nh_list;
+    //Insert new NH first and then existing route NH
+    comp_nh_list.push_back(nh_data1);
+
+    SecurityGroupList sg_list;
+    EcmpTunnelRouteAdd(bgp_peer, "vrf1", ip, 32,
+            comp_nh_list, false, "vn1", sg_list, PathPreference());
+    client->WaitForIdle();
+
+    DeleteVmportEnv(input, 2, false);
+    client->WaitForIdle();
+
+    struct PortInfo input1[] = {
+        {"vnet3", 3, "1.1.1.3", "00:00:00:01:01:01", 1, 3},
+        {"vnet4", 4, "1.1.1.4", "00:00:00:01:01:01", 1, 4},
+    };
+    CreateVmportWithEcmp(input1, 2, 1);
+    client->WaitForIdle();
+    //Add back the VM interface of ECMP
+    //This would result ing resync of route, due to policy change
+    CreateVmportWithEcmp(input, 1, 1);
+    client->WaitForIdle();
+    const VmInterface *vm_intf =
+        static_cast<const VmInterface *>(VmPortGet(1));
+
+    agent_->fabric_inet4_unicast_table()->
+        AddLocalVmRouteReq(bgp_peer, "vrf1", ip, 32,
+                MakeUuid(1), "vn1", vm_intf->label(),
+                SecurityGroupList(), false, PathPreference(), Ip4Address(0));
+    client->WaitForIdle();
+    EXPECT_TRUE(rt->GetActiveNextHop()->GetType() == NextHop::INTERFACE);
+
+    DeleteVmportEnv(input, 1, false);
+    DeleteVmportEnv(input1, 2, true);
+    WAIT_FOR(100, 1000, (VrfFind("vrf1") == false));
+    client->WaitForIdle();
+    EXPECT_FALSE(RouteFind("vrf1", ip, 32));
+}
+
 int main(int argc, char **argv) {
     GETUSERARGS();
     client = TestInit(init_file, ksync_init);