ipsec: enable UDP encap for IPv6 ESP tun protect

Type: improvement

If an SA protecting an IPv6 tunnel interface has UDP encapsulation
enabled, the code in esp_encrypt_inline() inserts a UDP header but does
not set the next protocol or the UDP payload length, so the peer that
receives the packet drops it. Set the next protocol field and the UDP
payload length correctly.

The port(s) for UDP encapsulation of IPsec was not registered for IPv6.
Add this registration for IPv6 SAs when UDP encapsulation is enabled.

Add punt handling for IPv6 IKE on NAT-T port.
Add registration of linux-cp for the new punt reason.
Add unit tests of IPv6 ESP w/ UDP encapsulation on tun protect

Signed-off-by: Matthew Smith <mgsmith@netgate.com>
Change-Id: Ibb28e423ab8c7bcea2c1964782a788a0f4da5268

1 files changed, 11 insertions, 13 deletions

diff --git a/src/vnet/ipsec/esp_encrypt.c b/src/vnet/ipsec/esp_encrypt.c
index d28f4f5e425..4ed3bf72c3f 100644
--- a/src/vnet/ipsec/esp_encrypt.c
+++ b/src/vnet/ipsec/esp_encrypt.c
@@ -887,42 +887,40 @@ esp_encrypt_inline (vlib_main_t *vm, vlib_node_runtime_t *node,
 	  else
 	    l2_len = 0;
 
+	  u16 len;
+	  len = payload_len_total + hdr_len - l2_len;
+
 	  if (VNET_LINK_IP6 == lt)
 	    {
 	      ip6_header_t *ip6 = (ip6_header_t *) (old_ip_hdr);
 	      if (PREDICT_TRUE (NULL == ext_hdr))
 		{
 		  *next_hdr_ptr = ip6->protocol;
-		  ip6->protocol = IP_PROTOCOL_IPSEC_ESP;
+		  ip6->protocol =
+		    (udp) ? IP_PROTOCOL_UDP : IP_PROTOCOL_IPSEC_ESP;
 		}
 	      else
 		{
 		  *next_hdr_ptr = ext_hdr->next_hdr;
-		  ext_hdr->next_hdr = IP_PROTOCOL_IPSEC_ESP;
+		  ext_hdr->next_hdr =
+		    (udp) ? IP_PROTOCOL_UDP : IP_PROTOCOL_IPSEC_ESP;
 		}
 	      ip6->payload_length =
-		clib_host_to_net_u16 (payload_len_total + hdr_len - l2_len -
-				      sizeof (ip6_header_t));
+		clib_host_to_net_u16 (len - sizeof (ip6_header_t));
 	    }
 	  else if (VNET_LINK_IP4 == lt)
 	    {
-	      u16 len;
 	      ip4_header_t *ip4 = (ip4_header_t *) (old_ip_hdr);
 	      *next_hdr_ptr = ip4->protocol;
-	      len = payload_len_total + hdr_len - l2_len;
-	      if (udp)
-		{
-		  esp_update_ip4_hdr (ip4, len, /* is_transport */ 1, 1);
-		  udp_len = len - ip_len;
-		}
-	      else
-		esp_update_ip4_hdr (ip4, len, /* is_transport */ 1, 0);
+	      esp_update_ip4_hdr (ip4, len, /* is_transport */ 1,
+				  (udp != NULL));
 	    }
 
 	  clib_memcpy_le64 (ip_hdr, old_ip_hdr, ip_len);
 
 	  if (udp)
 	    {
+	      udp_len = len - ip_len;
 	      esp_fill_udp_hdr (sa0, udp, udp_len);
 	    }