nicira_ext: Support DEC_NSH_TTL action

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

doc/source/nicira_ext_ref.rst

@@ -54,6 +54,7 @@ The followings shows the supported NXAction classes in OpenFlow1.0 or later
 .. autoclass:: NXActionCT
 .. autoclass:: NXActionNAT
 .. autoclass:: NXActionOutputTrunc
+.. autoclass:: NXActionDecNshTtl
 .. autoclass:: NXFlowSpecMatch
 .. autoclass:: NXFlowSpecLoad
 .. autoclass:: NXFlowSpecOutput

ryu/ofproto/nicira_ext.py

@@ -62,6 +62,7 @@ NXAST_NAT = 36
 NXAST_CONTROLLER2 = 37
 NXAST_SAMPLE2 = 38
 NXAST_OUTPUT_TRUNC = 39
+NXAST_DEC_NSH_TTL = 48
 
 NX_ACTION_RESUBMIT_PACK_STR = '!HHIHHB3x'
 NX_ACTION_RESUBMIT_SIZE = 16

ryu/ofproto/nx_actions.py

@@ -2984,6 +2984,41 @@ def generate(ofp_name, ofpp_name):
                           self.max_len)
             return data
 
+    class NXActionDecNshTtl(NXAction):
+        """
+        Decrement NSH TTL action
+
+        This action decrements the TTL in the Network Service Header(NSH).
+
+        This action was added in OVS v2.9.
+
+        And equivalent to the followings action of ovs-ofctl command.
+
+        ::
+
+            dec_nsh_ttl
+
+        Example::
+
+            actions += [parser.NXActionDecNshTtl()]
+        """
+        _subtype = nicira_ext.NXAST_DEC_NSH_TTL
+
+        _fmt_str = '!6x'
+
+        def __init__(self,
+                     type_=None, len_=None, vendor=None, subtype=None):
+            super(NXActionDecNshTtl, self).__init__()
+
+        @classmethod
+        def parser(cls, buf):
+            return cls()
+
+        def serialize_body(self):
+            data = bytearray()
+            msg_pack_into(self._fmt_str, data, 0)
+            return data
+
     def add_attr(k, v):
         v.__module__ = ofpp.__name__  # Necessary for stringify stuff
         setattr(ofpp, k, v)
@@ -3032,6 +3067,7 @@ def generate(ofp_name, ofpp_name):
         'NXFlowSpecMatch',
         'NXFlowSpecLoad',
         'NXFlowSpecOutput',
+        'NXActionDecNshTtl',
     ]
     vars = locals()
     for name in classes: