test: Add a manual test to simulate DTMF handling in osmo-sip-connector

Add a manul test to the contrib folder that helped and can help during
the development of osmo-sip-connector or similar software. This avoids
having to create a separate mncc module.

It can be started like:

$ PYTHONPATH=$PWD/../ python manual_test_server.py

Change-Id: I7f62efbc62455e6fcb1f091afb5fa120099834f0

contrib/manual_test_server.py

@@ -0,0 +1,126 @@
+import mncc
+import mncc_sock
+import ctypes
+import socket
+
+GSM340_PLAN_ISDN = 1
+GSM340_TYPE_NATIONAL = 2
+
+class MnccMessageBuilder(object):
+    """
+    I help in creating messages...
+    """
+    @staticmethod
+    def build_hello():
+        hello = mncc.gsm_mncc_hello()
+        hello.msg_type = mncc.MNCC_SOCKET_HELLO
+        hello.version = mncc.MNCC_SOCK_VERSION
+        hello.mncc_size = ctypes.sizeof(mncc.gsm_mncc)
+        hello.data_frame_size = ctypes.sizeof(mncc.gsm_data_frame)
+        hello.called_offset = mncc.gsm_mncc.called.offset
+        hello.signal_offset = mncc.gsm_mncc.signal.offset
+        hello.emergency_offset = mncc.gsm_mncc.emergency.offset
+        hello.lchan_type_offset = mncc.gsm_mncc.lchan_type.offset
+        return hello
+
+    @staticmethod
+    def build_mncc_number(number):
+        return mncc.gsm_mncc_number(
+                type=GSM340_TYPE_NATIONAL,
+                plan=GSM340_PLAN_ISDN,
+                number=number)
+
+    @staticmethod
+    def build_setup_ind(calling, called, callref=1):
+        setup = mncc.gsm_mncc()
+        setup.msg_type = mncc.MNCC_SETUP_IND
+        setup.callref = callref
+        setup.fields = mncc.MNCC_F_CALLED | mncc.MNCC_F_CALLING
+        setup.called = MnccMessageBuilder.build_mncc_number(called)
+        setup.calling = MnccMessageBuilder.build_mncc_number(calling)
+        return setup
+
+    @staticmethod
+    def build_setup_cmpl_ind(callref=1):
+        setup = mncc.gsm_mncc()
+        setup.msg_type = mncc.MNCC_SETUP_COMPL_IND
+        setup.callref = callref
+        return setup
+
+    @staticmethod
+    def build_rtp_msg(msg_type, callref, addr, port):
+        return mncc.gsm_mncc_rtp(
+                    msg_type=msg_type, callref=callref,
+                    ip=addr, port=port,
+                    #payload_type=3,
+                    #payload_msg_type=mncc.GSM_TCHF_FRAME)
+                    payload_type=98,
+                    payload_msg_type=mncc.GSM_TCH_FRAME_AMR)
+
+    @staticmethod
+    def build_dtmf_start(callref, data):
+        return mncc.gsm_mncc(
+                    msg_type=mncc.MNCC_START_DTMF_IND,
+                    callref=callref,
+                    fields=mncc.MNCC_F_KEYPAD,
+                    keypad=ord(data))
+
+    @staticmethod
+    def build_dtmf_stop(callref, data):
+        return mncc.gsm_mncc(
+                    callref=callref,
+                    msg_type=mncc.MNCC_STOP_DTMF_IND)
+
+def send_dtmf(callref):
+    global conn
+
+    conn.send_msg(MnccMessageBuilder.build_dtmf_start(callref, '1'))
+    conn.send_msg(MnccMessageBuilder.build_dtmf_stop(callref, '1'))
+    conn.send_msg(MnccMessageBuilder.build_dtmf_start(callref, '2'))
+    conn.send_msg(MnccMessageBuilder.build_dtmf_stop(callref, '2'))
+
+
+server = mncc_sock.MnccSocketServer()
+conn = server.accept()
+
+# Say hello and set-up a call
+conn.send_msg(MnccMessageBuilder.build_hello())
+conn.send_msg(MnccMessageBuilder.build_setup_ind("1234", "5000"))
+print("=> Sent hello + setup indication")
+
+# Wait for the RTP crate.. and actknowledge it..
+msg = conn.recv()
+assert msg.msg_type == mncc.MNCC_RTP_CREATE
+print("<= Received request to create a RTP socket")
+conn.send_msg(MnccMessageBuilder.build_rtp_msg(mncc.MNCC_RTP_CREATE,
+                                                msg.callref,
+                                                #socket.INADDR_LOOPBACK, 4000))
+                                                socket.INADDR_ANY, 4000))
+print("=> Claimed socket was created...")
+
+msg = conn.recv()
+assert msg.msg_type == mncc.MNCC_CALL_PROC_REQ
+print("<= Received proceeding...")
+
+
+
+while True:
+    msg = conn.recv()
+    if msg.msg_type == mncc.MNCC_ALERT_REQ:
+        print("=> I should alert...")
+        continue
+    if msg.msg_type == mncc.MNCC_RTP_CONNECT:
+        conn.send_msg(MnccMessageBuilder.build_rtp_msg(mncc.MNCC_RTP_CONNECT,
+                                                msg.callref,
+                                                socket.INADDR_LOOPBACK, 4000))
+        print("=> I needed to connect RTP...")
+        continue
+    if msg.msg_type == mncc.MNCC_SETUP_RSP:
+        print("=> Call is connected?")
+        conn.send_msg(MnccMessageBuilder.build_setup_cmpl_ind(msg.callref))
+        send_dtmf(msg.callref)
+        continue
+
+    print(msg)
+    print(msg.msg_type)
+print(type(msg))