l2tp: l2tp-decap-local don't accept packets unless configured

Change-Id: I2e48eb772dc44912192d0684b8ee631d8d975e9e
Signed-off-by: Jakub Grajciar <jgrajcia@cisco.com>

src/vnet/l2tp/decap.c

@@ -292,14 +292,6 @@ VLIB_REGISTER_NODE (l2t_decap_local_node) = {
 };
 /* *INDENT-ON* */
 
-#ifndef CLIB_MARCH_VARIANT
-void
-l2tp_decap_init (void)
-{
-  ip6_register_protocol (IP_PROTOCOL_L2TP, l2t_decap_local_node.index);
-}
-#endif /* CLIB_MARCH_VARIANT */
-
 /*
  * fd.io coding-style-patch-verification: ON
  *

src/vnet/l2tp/l2tp.c

@@ -399,6 +399,12 @@ create_l2tpv3_ipv6_tunnel (l2t_main_t * lm,
   if (sw_if_index)
     *sw_if_index = hi->sw_if_index;
 
+  if (!lm->proto_registered)
+    {
+      ip6_register_protocol (IP_PROTOCOL_L2TP, l2t_decap_local_node.index);
+      lm->proto_registered = true;
+    }
+
   return 0;
 }
 
@@ -729,9 +735,10 @@ l2tp_init (vlib_main_t * vm)
   pi = ip_get_protocol_info (im, IP_PROTOCOL_L2TP);
   pi->unformat_pg_edit = unformat_pg_l2tp_header;
 
+  lm->proto_registered = false;
+
   /* insure these nodes are included in build */
   l2tp_encap_init (vm);
-  l2tp_decap_init ();
 
   return 0;
 }

src/vnet/l2tp/l2tp.h

@@ -80,6 +80,8 @@ typedef struct
   vlib_main_t *vlib_main;
   vnet_main_t *vnet_main;
 
+  bool proto_registered;
+
 } l2t_main_t;
 
 /* Packet trace structure */
@@ -118,7 +120,6 @@ typedef struct
 uword unformat_pg_l2tp_header (unformat_input_t * input, va_list * args);
 
 void l2tp_encap_init (vlib_main_t * vm);
-void l2tp_decap_init (void);
 int create_l2tpv3_ipv6_tunnel (l2t_main_t * lm,
 			       ip6_address_t * client_address,
 			       ip6_address_t * our_address,

test/test_l2tp.py

@@ -0,0 +1,48 @@
+#!/usr/bin/env python
+
+import unittest
+
+from scapy.layers.l2 import Ether
+from scapy.layers.inet6 import IPv6
+
+from framework import VppTestCase
+
+
+class TestL2tp(VppTestCase):
+    """ L2TP Test Case """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestL2tp, cls).setUpClass()
+
+        cls.create_pg_interfaces(range(1))
+        cls.pg0.admin_up()
+        cls.pg0.config_ip6()
+
+    def test_l2tp_decap_local(self):
+        """ L2TP don't accept packets unless configured """
+
+        pkt = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+               IPv6(src=self.pg0.remote_ip6, dst=self.pg0.local_ip6, nh=115))
+
+        self.pg0.add_stream(pkt)
+        self.pg_start()
+
+        # l2tp should not accept packets
+        err = self.statistics.get_counter(
+            '/err/l2tp-decap-local/l2tpv3 session not found')[0]
+        self.assertEqual(err, 0)
+        err_count = err
+
+        self.vapi.l2tpv3_create_tunnel(client_address=self.pg0.local_ip6n,
+                                       our_address=self.pg0.remote_ip6n,
+                                       is_ipv6=1)
+
+        self.pg0.add_stream(pkt)
+        self.pg_start()
+
+        # l2tp accepts packets
+        err = self.statistics.get_counter(
+            '/err/l2tp-decap-local/l2tpv3 session not found')[0]
+        self.assertEqual(err, 1)
+        err_count = err