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, 26 insertions, 2 deletions

diff --git a/Documentation/ref/ovs-actions.7.rst b/Documentation/ref/ovs-actions.7.rst
index 7224896df..b59b7634f 100644
--- a/Documentation/ref/ovs-actions.7.rst
+++ b/Documentation/ref/ovs-actions.7.rst
@@ -212,12 +212,13 @@ Unsupported packet type
   is not an L3 packet, and ``encap(nsh)`` raises this error if the current
   packet is not Ethernet, IPv4, IPv6, or NSH.
 
+  The ``decap`` action is supported only for packet types ethernet, NSH and
+  MPLS.  Openvswitch raises this error for other packet types.
   When a ``decap`` action decapsulates a packet, Open vSwitch raises this error
   if it does not support the type of inner packet.  ``decap`` of an Ethernet
   header raises this error if a VLAN header is present, ``decap`` of a NSH
   packet raises this error if the NSH inner packet is not Ethernet, IPv4, IPv6,
-  or NSH, and ``decap`` of other types of packets is unsupported and also
-  raises this error.
+  or NSH.
 
   This error terminates packet processing, retaining any previous side effects
   (e.g. output actions).  When this error arises within the execution of a
@@ -995,6 +996,8 @@ The ``encap`` action
   | ``encap(nsh([md_type=``\ *md_type*\
                  ``], [tlv(``\ *class*,\ *type*,\ *value*\ ``)]...))``
   | ``encap(ethernet)``
+  | ``encap(mpls)``
+  | ``encap(mpls_mc)``
 
 The ``encap`` action encapsulates a packet with a specified header.  It has
 variants for different kinds of encapsulation.
@@ -1018,10 +1021,20 @@ frame.  The Ethernet type is initialized to the L3 packet's type, e.g. 0x0800
 if the L3 packet is IPv4.  The Ethernet source and destination are initially
 zeroed.
 
+The ``encap(mpls)`` variant adds a MPLS header at the start of the packet.
+When encap(ethernet) is applied after this action, the ethertype of ethernet
+header will be populated with MPLS unicast ethertype (``0x8847``).
+
+The ``encap(mpls_mc)`` variant adds a MPLS header at the start of the packet.
+When encap(ethernet) is applied after this action, the ethertype of ethernet
+header will be populated with MPLS multicast ethertype (``0x8848``).
+
 **Conformance**
   This action is an Open vSwitch extension to OpenFlow 1.3 and later,
   introduced in Open vSwitch 2.8.
 
+  The MPLS support for this action is added in Open vSwitch 2.17.
+
 
 The ``decap`` action
 --------------------
@@ -1030,6 +1043,7 @@ The ``decap`` action
 
 **Syntax**:
   | ``decap``
+  | ``decap(packet_type(ns=``\ *namespace,*\ ``type=``\ *type*\ ``))``
 
 Removes an outermost encapsulation from the packet:
 
@@ -1042,12 +1056,22 @@ Removes an outermost encapsulation from the packet:
     and NSH inner packet types.  Other types raise unsupported packet type
     errors.
 
+  - Otherwise, if the packet is encapsulated inside a MPLS header, removes
+    the MPLS header and classifies the inner packet as mentioned in the packet
+    type argument of the decap.  The *packet_type* field specifies the type of
+    the packet in the format specified in OpenFlow 1.5 chapter
+    `7.2.3.11 Packet Type Match Field`.  The inner packet will be incorrectly
+    classified, if the inner packet is different from mentioned in the
+    *packet_type* field.
+
   - Otherwise, raises an unsupported packet type error.
 
 **Conformance**
   This action is an Open vSwitch extension to OpenFlow 1.3 and later,
   introduced in Open vSwitch 2.8.
 
+  The MPLS support for this action is added in Open vSwitch 2.17.
+
 
 Field Modification Actions
 ==========================