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#!/usr/bin/env python3
# Python interface to OsmoNITB MNCC (Mobile Network Call Control)
# interface
#
# (C) 2015 by Harald Welte <laforge@gnumonks.org>
# (C) 2018 by Vadim Yanitskiy <axilirator@gmail.com>
#
# Licensed under GNU General Public License, Version 2 or at your
# option, any later version.
import logging as log
import socket
import os
import mncc
import ctypes
class mncc_msg_common:
def send(self):
return bytes(memoryview(self))
def receive(self, bytes):
fit = min(len(bytes), ctypes.sizeof(self))
ctypes.memmove(ctypes.addressof(self), bytes, fit)
# Message type matching
def is_rtp(self):
return self.msg_type in (mncc.MNCC_RTP_CREATE,
mncc.MNCC_RTP_CONNECT, mncc.MNCC_RTP_FREE)
def is_frame(self):
return self.msg_type in (mncc.GSM_TCHF_FRAME,
mncc.GSM_TCHH_FRAME, mncc.GSM_TCHF_FRAME_EFR,
mncc.GSM_TCH_FRAME_AMR, mncc.GSM_BAD_FRAME)
class mncc_msg(mncc.struct_gsm_mncc, mncc_msg_common):
def __str__(self):
return 'mncc_msg(type=0x%04x, callref=%u, fields=0x%04x)' % (self.msg_type, self.callref, self.fields)
def __unicode__(self):
return u'mncc_msg(type=0x%04x, callref=%u, fields=0x%04x)' % (self.msg_type, self.callref, self.fields)
class mncc_hello_msg(mncc.struct_gsm_mncc_hello, mncc_msg_common):
def __str__(self):
return 'mncc_hello_msg(version=0x%04x)' % (self.version)
def __unicode__(self):
return u'mncc_hello_msg(version=0x%04x)' % (self.version)
class mncc_data_frame_msg(mncc.struct_gsm_data_frame, mncc_msg_common):
def __str__(self):
return 'mncc_data_frame(type=0x%04x, codec=%s, callref=%u)' \
% (self.msg_type, self.codec_str(), self.callref)
def __unicode__(self):
return u'mncc_data_frame(type=0x%04x, codec=%s, callref=%u)' \
% (self.msg_type, self.codec_str(), self.callref)
def codec_str(self):
if self.msg_type == mncc.GSM_TCHF_FRAME:
return "FR"
elif self.msg_type == mncc.GSM_TCHH_FRAME:
return "HR"
elif self.msg_type == mncc.GSM_TCHF_FRAME_EFR:
return "EFR"
elif self.msg_type == mncc.GSM_TCH_FRAME_AMR:
return "AMR"
elif self.msg_type == mncc.GSM_BAD_FRAME:
return "(BFI)"
else:
return "(???)"
def pad(x, l):
if len(x) < l:
return x + (l - len(x)) * b'\x00'
else:
return x
class mncc_rtp_msg(mncc.struct_gsm_mncc_rtp, mncc_msg_common):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
# we have to do this here to make sure our setters below are used
if 'ip' in kwargs:
self.ip = kwargs['ip']
if 'port' in kwargs:
self.port = kwargs['port']
@property
def ip(self):
assert self.addr.ss_family == 2
return int.from_bytes(self.addr.ss_padding[2:6], 'big')
@ip.setter
def ip(self, val):
self.addr.ss_family = 2
val = pad(self.addr.ss_padding[:2], 2) + val.to_bytes(4, 'big') + self.addr.ss_padding[6:]
self.addr.ss_padding = val
@property
def port(self):
return int.from_bytes(self.addr.ss_padding[:2], 'big')
@port.setter
def port(self, val):
self.addr.ss_family = 2
self.addr.ss_padding = val.to_bytes(2, 'big') + self.addr.ss_padding[2:]
def __str__(self):
return 'mncc_rtp_msg(type=0x%04x, callref=%u, ip=%x, port=%u)' % (self.msg_type, self.callref, self.ip, self.port)
def __unicode__(self):
return u'mncc_rtp_msg(type=0x%04x, callref=%u, ip=%x, port=%u)' % (self.msg_type, self.callref, self.ip, self.port)
class mncc_bridge_msg(mncc.struct_gsm_mncc_bridge, mncc_msg_common):
def __str__(self):
return 'mncc_bridge_msg(%u, %u)' % (self.callref[0], self.callref[1])
def __unicode__(self):
return u'mncc_bridge_msg(%u, %u)' % (self.callref[0], self.callref[1])
def mncc_number(number, num_type = 0, num_plan = 0, num_present = 1, num_screen = 0):
return mncc.struct_gsm_mncc_number(number = number.encode('utf-8'), type = num_type,
plan = num_plan, present = num_present,
screen = num_screen)
def mncc_bearer_cap(codecs_permitted):
speech_ver = ctypes.c_int * 8
speech_types = speech_ver()
index = 0
for codec in codecs_permitted:
speech_types[index] = codec
index = index + 1
speech_types[index] = -1
return mncc.struct_gsm_mncc_bearer_cap(coding = 0, speech_ctm=0, radio = 1, speech_ver = speech_types, transfer = 0, mode = 0)
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()
ms.receive(data)
if ms.is_rtp():
ms = mncc_rtp_msg()
ms.receive(data)
elif ms.is_frame():
ms = mncc_data_frame_msg()
ms.receive(data)
elif ms.msg_type == mncc.MNCC_SOCKET_HELLO:
ms = mncc_hello_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)
log.info('Connecting to %s' % address)
self.sock.connect(address)
# Check the HELLO message
self.check_hello()
def check_hello(self):
log.debug('Waiting for HELLO message...')
msg = self.recv()
# Match expected message type
if msg.msg_type != mncc.MNCC_SOCKET_HELLO:
raise AssertionError('Received an unknown (!= MNCC_SOCKET_HELLO) '
'message: %s\n' % msg)
# Match expected protocol version
if msg.version != mncc.MNCC_SOCK_VERSION:
raise AssertionError('MNCC protocol version mismatch '
'(0x%04x vs 0x%04x)\n' % (msg.version, mncc.MNCC_SOCK_VERSION))
# Match expected message sizes / offsets
if (msg.mncc_size < ctypes.sizeof(mncc.struct_gsm_mncc) or
msg.data_frame_size != ctypes.sizeof(mncc.struct_gsm_data_frame) or
msg.called_offset != mncc.struct_gsm_mncc.called.offset or
msg.signal_offset != mncc.struct_gsm_mncc.signal.offset or
msg.emergency_offset != mncc.struct_gsm_mncc.emergency.offset or
msg.lchan_type_offset != mncc.struct_gsm_mncc.lchan_type.offset):
raise AssertionError('MNCC message alignment mismatch\n')
log.info('Received %s' % msg)
class MnccSocketServer(object):
def __init__(self, address = '/tmp/bsc_mncc'):
if os.path.exists(address):
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
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