Double path delete request in succession.

Problem:
In stale path cleanup, if no stale path was found function used to clean last
path seen. This resulted in not related path getting deleted. In case of OVS
delete the path to be deleted was already gone because of bug and table deleted,
resulting in ceash.

Solution:
Delete if relevant path is found.
Closes-bug: #1571598

Change-Id: I25bd7cec4c0774d0a041286c15af99bc5a2d1ada

src/vnsw/agent/oper/agent_route.cc

@@ -532,12 +532,11 @@ void AgentRouteTable::SquashStalePaths(AgentRoute *route,
         if (path->is_stale() && (path != exception_path)) {
             // Since we squash stales, at any point of time there should be only
             // one stale other than exception_path in list
-            break;
+            DeletePathFromPeer(route->get_table_partition(), route, path);
+            return;
         }
         it++;
     }
-    DeletePathFromPeer(route->get_table_partition(), route, path);
-    return;
 }
 
 uint32_t AgentRoute::GetActiveLabel() const {

src/vnsw/agent/test/test_l2route.cc

@@ -1585,6 +1585,62 @@ TEST_F(RouteTest, StalePathDeleteRouteDelete) {
     client->WaitForIdle();
 }
 
+class SetupTask : public Task {
+    public:
+        SetupTask(RouteTest *test, std::string name) :
+            Task((TaskScheduler::GetInstance()->
+                  GetTaskId("db::DBTable")), 0), test_(test),
+            test_name_(name) {
+        }
+
+        virtual bool Run() {
+            if (test_name_ == "SquashPathTest_1") {
+                char local_vm_mac_str_[100];
+                MacAddress  local_vm_mac_;
+                Ip4Address  local_vm_ip4_;
+                char local_vm_ip4_str_[100];
+                strcpy(local_vm_ip4_str_, "1.1.1.10");
+                local_vm_ip4_ = Ip4Address::from_string(local_vm_ip4_str_);
+                strcpy(local_vm_mac_str_, "00:00:01:01:01:10");
+                local_vm_mac_ = MacAddress::FromString(local_vm_mac_str_);
+                EvpnRouteEntry *rt = EvpnRouteGet("vrf1",
+                                                  local_vm_mac_,
+                                                  local_vm_ip4_,
+                                                  0);
+                const VrfEntry *vrf = VrfGet("vrf1");
+                vrf->GetEvpnRouteTable()->SquashStalePaths(rt, NULL);
+            }
+            return true;
+        }
+    std::string Description() const { return "SetupTask"; }
+    private:
+        RouteTest *test_;
+        std::string test_name_;
+};
+
+//Bug# 1571598 
+TEST_F(RouteTest, SquashPathTest_1) {
+    struct PortInfo input[] = {
+        {"vnet1", 1, "1.1.1.10", "00:00:01:01:01:10", 1, 1},
+    };
+
+    client->Reset();
+    CreateVmportEnv(input, 1);
+    client->WaitForIdle();
+
+    EvpnRouteEntry *rt = EvpnRouteGet("vrf1", local_vm_mac_, local_vm_ip4_, 0);
+    EXPECT_TRUE(rt != NULL);
+    EXPECT_TRUE(rt->GetActivePath() != NULL);
+    SetupTask * task = new SetupTask(this, "SquashPathTest_1");
+    TaskScheduler::GetInstance()->Enqueue(task);
+    client->WaitForIdle();
+    rt = EvpnRouteGet("vrf1", local_vm_mac_, local_vm_ip4_, 0);
+    EXPECT_TRUE(rt != NULL);
+
+    DeleteVmportEnv(input, 1, true);
+    client->WaitForIdle();
+}
+
 int main(int argc, char *argv[]) {
     ::testing::InitGoogleTest(&argc, argv);
     GETUSERARGS();