xid: improve xid handling

Generate xid for ofp message instead of always 0.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

ryu/controller/controller.py

@@ -16,6 +16,7 @@
 import gflags
 import logging
 import gevent
+import random
 from gevent.server import StreamServer
 from gevent.queue import Queue
 
@@ -86,6 +87,7 @@ class Datapath(object):
         self.version_recv = None
         self.version_used = None
         self.set_version(max(self.supported_ofp_version))
+        self.xid = random.randint(0, self.ofproto.MAX_XID)
         self.id = None  # datapath_id is unknown yet
         self.ports = None
 
@@ -128,8 +130,16 @@ class Datapath(object):
     def send(self, buf):
         self.send_q.put(buf)
 
+    def set_xid(self, msg):
+        self.xid += 1
+        self.xid &= self.ofproto.MAX_XID
+        msg.set_xid(self.xid)
+        return self.xid
+
     def send_msg(self, msg):
         assert isinstance(msg, self.ofproto_parser.MsgBase)
+        if msg.xid is None:
+            self.set_xid(msg)
         msg.serialize()
         # LOG.debug('send_msg %s', msg)
         self.send(msg.buf)

ryu/controller/handler.py

@@ -106,6 +106,7 @@ class EchoHandler(object):
         # LOG.debug('echo request msg %s %s', msg, str(msg.data))
         datapath = msg.datapath
         echo_reply = datapath.ofproto_parser.OFPEchoReply(datapath)
+        echo_reply.xid = msg.xid
         echo_reply.data = msg.data
         datapath.send_msg(echo_reply)
 

ryu/ofproto/ofproto_parser.py

@@ -66,6 +66,10 @@ class MsgBase(object):
         self.msg_len = msg_len
         self.xid = xid
 
+    def set_xid(self, xid):
+        assert self.xid is None
+        self.xid = xid
+
     def set_buf(self, buf):
         self.buf = buffer(buf)
 
@@ -95,12 +99,12 @@ class MsgBase(object):
         assert self.version is not None
         assert self.msg_type is not None
         assert self.msg_len is None
-        assert self.xid is None
         assert self.buf is not None
         assert len(self.buf) >= self.datapath.ofproto.OFP_HEADER_SIZE
 
         self.msg_len = len(self.buf)
-        self.xid = 0  # TODO:XXX
+        if self.xid is None:
+            self.xid = 0
 
         struct.pack_into(self.datapath.ofproto.OFP_HEADER_PACK_STR, self.buf, 0,
                          self.version, self.msg_type, self.msg_len, self.xid)