New openvswitch MPLS actions for layer 2 tunnelling

From: Martin Varghese <martin.varghese@nokia.com>

The existing PUSH MPLS action inserts 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 (l2 tunnelling) requirements. In L2 VPN the MPLS header should
encapsulate the ethernet packet.

The new mpls action ADD_MPLS inserts MPLS header at the start of the
packet or at the start of the l3 header depending on the value of l3 tunnel
flag in the ADD_MPLS arguments.

POP_MPLS action is extended to support ethertype 0x6558

OVS userspace changes -
---------------------
Encap & Decap ovs actions are extended to support MPLS packet type. The encap & decap
adds and removes MPLS header at the start of packet as depicted below.

Actions - encap(mpls(ether_type=0x8847)),encap(ethernet)

Incoming packet -> | ETH | IP | Payload |

1 Actions -  encap(mpls(ether_type=0x8847)) [Kernel action - add_mpls:0x8847]

        Outgoing packet -> | MPLS | ETH | Payload|

2 Actions - encap(ethernet) [ Kernel 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() [Kernel action - pop_eth)

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

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

        Outgoing packet -> | ETH  | IP | Payload

Martin Varghese (3):
  net: skb_mpls_push() modified to allow MPLS header push at start of
    packet.
  net: Rephrased comments section of skb_mpls_pop()
  openvswitch: New MPLS actions for layer 2 tunnelling

 include/uapi/linux/openvswitch.h | 31 +++++++++++++++++++++++++++++++
 net/core/skbuff.c                | 10 +++++++---
 net/openvswitch/actions.c        | 30 ++++++++++++++++++++++++------
 net/openvswitch/flow_netlink.c   | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 96 insertions(+), 9 deletions(-)

-- 
1.8.3.1