ikev2: fix lookup in wrong ip table

In responder mode we need to remember interface index from which IKE
session was initiated. Otherwise when sending keep alive packets to the
initiator, the default ip table is always used for lookup instead of the
one associated with the interface.

Type: fix

Change-Id: Iade3fc3a490b7ae83c3f6e9014d1f4204e476ac1
Signed-off-by: Filip Tehlar <ftehlar@cisco.com>

src/plugins/ikev2/ikev2.c

@@ -716,9 +716,8 @@ ikev2_check_payload_length (const ike_payload_header_t * ikep, int rlen,
 }
 
 static int
-ikev2_process_sa_init_req (vlib_main_t * vm,
-			   ikev2_sa_t * sa, ike_header_t * ike,
-			   udp_header_t * udp, u32 len)
+ikev2_process_sa_init_req (vlib_main_t *vm, ikev2_sa_t *sa, ike_header_t *ike,
+			   udp_header_t *udp, u32 len, u32 sw_if_index)
 {
   u8 nonce[IKEV2_NONCE_SIZE];
   int p = 0;
@@ -733,6 +732,7 @@ ikev2_process_sa_init_req (vlib_main_t * vm,
 		       ip_addr_version (&sa->iaddr) == AF_IP4);
 
   sa->ispi = clib_net_to_host_u64 (ike->ispi);
+  sa->sw_if_index = sw_if_index;
 
   /* store whole IKE payload - needed for PSK auth */
   vec_reset_length (sa->last_sa_init_req_packet_data);
@@ -2958,7 +2958,9 @@ ikev2_node_internal (vlib_main_t * vm,
 		      goto dispatch0;
 		    }
 
-		  res = ikev2_process_sa_init_req (vm, sa0, ike0, udp0, rlen);
+		  res = ikev2_process_sa_init_req (
+		    vm, sa0, ike0, udp0, rlen,
+		    vnet_buffer (b0)->sw_if_index[VLIB_RX]);
 		  if (!res)
 		    vlib_node_increment_counter (vm, node->node_index,
 						 IKEV2_ERROR_MALFORMED_PACKET,