Files
osmo-mgw/openbsc/contrib/nat/ussd_example.py
Holger Hans Peter Freyther 3a434f8e8c nat/ussd: Add an example of the USSD gateway side-channel
This adds a very basic, use once example in python on how to connect
and deal with the app specific payload and messages. The code is not
complete as the invokeId should be patched according to the initial
invoke. This excercise is left to future readers of that code.
2016-04-16 15:56:13 -04:00

66 lines
2.0 KiB
Python

#!/usr/bin/env python2.7
"""
AGPLv3+ 2016 Copyright Holger Hans Peter Freyther
Example of how to connect to the USSD side-channel and how to respond
with a fixed message.
"""
import socket
import struct
ussdSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
ussdSocket.connect(('127.0.0.1', 5001))
def send_dt1(dstref, data):
dlen = struct.pack('B', len(data)).encode('hex')
hex = '06' + dstref.encode('hex') + '00' + '01' + dlen + data.encode('hex')
pdata = hex.decode('hex')
out = struct.pack('>HB', len(pdata), 0xfd) + pdata
ussdSocket.send(out)
def send_rel(srcref, dstref):
hex = '04' + dstref.encode('hex') + srcref.encode('hex') + '000100'
pdata = hex.decode('hex')
out = struct.pack('>HB', len(pdata), 0xfd) + pdata
ussdSocket.send(out)
def recv_one():
plen = ussdSocket.recv(3)
(plen,ptype) = struct.unpack(">HB", plen)
data = ussdSocket.recv(plen)
return ptype, data
# Assume this is the ID request
data = ussdSocket.recv(4)
ussdSocket.send("\x00\x08\xfe\x05\x00" + "\x05\x01" + "ussd")
# ^len ^len of tag ... and ignore
# Expect a fake message. see struct ipac_msgt_sccp_state
ptype, data = recv_one()
print("%d %s" % (ptype, data.encode('hex')))
(srcref, dstref, transid, invokeid) = struct.unpack("<3s3sBB", data[1:9])
print("New transID %d invoke %d" % (transid, invokeid))
# Expect a the invocation.. todo.. extract invoke id
ptype, data = recv_one()
print("%d %s" % (ptype, data.encode('hex')))
# Reply with BSSAP + GSM 04.08 + MAP portion
# 00 == invoke id 0f == DCS
res = "01002a9b2a0802e1901c22a220020100301b02013b301604010f041155e7d2f9bc3a41412894991c06a9c9a713"
send_dt1(dstref, res.decode('hex'))
clear = "000420040109"
send_dt1(dstref, clear.decode('hex'))
# should be the clear complete
send_rel(srcref, dstref)
# Give it some time to handle connection shutdown properly
print("Gracefully sleeping")
import time
time.sleep(3)