mncc: Make it possible to build a MNCC server for testing

For manual testing the osmo-sip-connector it is nice to run a custom
MNCC server to mock certain behavior. Refactor the socket class to
share code between client/server.

Change-Id: I8387fe1687557c6a1a26ff1e0cc9dbff3087aa82

mncc_sock.py

@@ -52,22 +52,14 @@ def mncc_number(number, num_type = 0, num_plan = 0, num_present = 1, num_screen
                                 plan = num_plan, present = num_present,
                                 screen = num_screen)
 
-class MnccSocket(object):
-    def __init__(self, address = '/tmp/bsc_mncc'):
-        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
-        print 'connecting to %s' % address
-        try:
-            self.sock.connect(address)
-        except socket.error, errmsg:
-            print >>sys.stderr, errmsg
-            sys.exit(1)
-
-        # FIXME: parse the HELLO message
-        msg = self.recv()
-
+class MnccSocketBase(object):
     def send(self, msg):
         return self.sock.sendall(msg.send())
 
+    def send_msg(self, msg):
+        data = buffer(msg)[:]
+        return self.sock.sendall(data)
+
     def recv(self):
         data = self.sock.recv(1500)
         ms = mncc_msg()
@@ -76,3 +68,30 @@ class MnccSocket(object):
                ms = mncc_rtp_msg()
                ms.receive(data)
         return ms
+
+class MnccSocket(MnccSocketBase):
+    def __init__(self, address = '/tmp/bsc_mncc'):
+        super(MnccSocketBase, self).__init__()
+        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
+        print('connecting to %s' % address)
+        try:
+            self.sock.connect(address)
+        except socket.error as errmsg:
+            sys.stderr.write("%s\n" % errmsg)
+            sys.exit(1)
+
+        # FIXME: parse the HELLO message
+        msg = self.recv()
+
+class MnccSocketServer(object):
+    def __init__(self, address = '/tmp/bsc_mncc'):
+        os.unlink(address)
+        self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_SEQPACKET)
+        self.sock.bind(address)
+        self.sock.listen(5)
+
+    def accept(self):
+        (fd,_) = self.sock.accept()
+        sock = MnccSocketBase()
+        sock.sock = fd
+        return sock