Encap & Decap actions for MPLS packet type.

The encap & decap actions are extended to support MPLS packet type.
Encap & decap actions adds and removes MPLS header at start of the
packet.

The existing PUSH MPLS & POP MPLS actions inserts & removes MPLS
header between ethernet header and the IP header. Though this behaviour
is fine for L3 VPN where an IP packet is encapsulated inside a MPLS
tunnel, it does not suffice the L2 VPN requirements. In L2 VPN the
ethernet packets must be encapsulated inside MPLS tunnel.

In this change the encap & decap actions are extended to support MPLS
packet type. The encap & decap adds and removes MPLS header at the
start of packet as depicted below.

Encapsulation:

Actions - encap(mpls),encap(ethernet)

Incoming packet -> | ETH | IP | Payload |

1 Actions -  encap(mpls) [Datapath action - ADD_MPLS:0x8847]

        Outgoing packet -> | MPLS | ETH | Payload|

2 Actions - encap(ethernet) [ Datapath action - push_eth ]

        Outgoing packet -> | ETH | MPLS | ETH | Payload|

Decapsulation:

Incoming packet -> | ETH | MPLS | ETH | IP | Payload |

Actions - decap(),decap(packet_type(ns=0,type=0))

1 Actions -  decap() [Datapath action - pop_eth)

        Outgoing packet -> | MPLS | ETH | IP | Payload|

2 Actions - decap(packet_type(ns=0,type=0)) [Datapath action - POP_MPLS:0x6558]

        Outgoing packet -> | ETH  | IP | Payload|

Signed-off-by: Martin Varghese <martin.varghese@nokia.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/lib/packets.c b/lib/packets.c
index 4a7643c5d..d0fba8176 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -418,6 +418,40 @@ push_mpls(struct dp_packet *packet, ovs_be16 ethtype, ovs_be32 lse)
     pkt_metadata_init_conn(&packet->md);
 }
 
+void
+add_mpls(struct dp_packet *packet, ovs_be16 ethtype, ovs_be32 lse,
+         bool l3_encap)
+{
+    if (!eth_type_mpls(ethtype)) {
+        return;
+    }
+
+    if (!l3_encap) {
+        ovs_be32 *header = dp_packet_push_uninit(packet, MPLS_HLEN);
+
+        *header = lse;
+        packet->l2_5_ofs = 0;
+        packet->packet_type = PACKET_TYPE_BE(OFPHTN_ETHERTYPE,
+                                             ntohs(ethtype));
+    } else {
+        size_t len;
+        char *header;
+
+        if (!is_mpls(packet)) {
+            /* Set MPLS label stack offset. */
+            packet->l2_5_ofs = packet->l3_ofs;
+        }
+        set_ethertype(packet, ethtype);
+
+        /* Push new MPLS shim header onto packet. */
+        len = packet->l2_5_ofs;
+        header = dp_packet_resize_l2_5(packet, MPLS_HLEN);
+        memmove(header, header + MPLS_HLEN, len);
+        memcpy(header + len, &lse, sizeof lse);
+    }
+    pkt_metadata_init_conn(&packet->md);
+}
+
 /* If 'packet' is an MPLS packet, removes its outermost MPLS label stack entry.
  * If the label that was removed was the only MPLS label, changes 'packet''s
  * Ethertype to 'ethtype' (which ordinarily should not be an MPLS
@@ -440,6 +474,18 @@ pop_mpls(struct dp_packet *packet, ovs_be16 ethtype)
         /* Invalidate offload flags as they are not valid after
          * decapsulation of MPLS header. */
         dp_packet_reset_offload(packet);
+
+        /* packet_type must be reset for the MPLS packets with no l2 header */
+        if (!len) {
+            if (ethtype == htons(ETH_TYPE_TEB)) {
+                /* The inner packet must be classified as ethernet if the
+                 * ethtype is ETH_TYPE_TEB. */
+                packet->packet_type = htonl(PT_ETH);
+            } else {
+                packet->packet_type = PACKET_TYPE_BE(OFPHTN_ETHERTYPE,
+                                                     ntohs(ethtype));
+            }
+        }
     }
 }