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+# Basic SDP parser for app_python
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+
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+Python script to be used from kamailio.cfg via app_python module (cached
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+here from mailing list).
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+
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+``` python
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+# -*- coding: utf-8 -*-
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+
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+import Router
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+
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+class OriginType:
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+ username = None
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+ sess_id = None
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+ sess_ver = None
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+ nettype = None
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+ addrtype = None
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+ unicast_addr = None
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+ RAW_STRING = None
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+
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+# WARNING:
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+# Maybe in the format: <base multicast address>[/<ttl>]/<number of addresses>
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+# Examples:
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+# c=IN IP4 224.2.36.41/127
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+# c=IN IP4 224.2.36.42/127
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+# c=IN IP4 224.2.36.43/127
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+# c=IN IP4 224.2.1.1/127/3
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+# c=IN IP6 FF15::101/3
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+class ConnectionType:
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+ nettype = None
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+ addrtype = None
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+ connection_addr = None
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+ RAW_STRING = None
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+
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+# Formats:
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+# <media> <port> <proto> <fmt> ...
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+# <media> <port>/<number of ports> <proto> <fmt> ...
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+class MediaType:
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+ media = None
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+ port = None
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+ proto = None
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+ fmt = None
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+ args = ""
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+ RAW_STRING = None
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+
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+class SDPBodyMessage:
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+ origin = OriginType() # o=root 2135137275 2135137277 IN IP4 192.168.254.54
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+ session_name = None # s=Asterisk PBX 1.8.7.1
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+ conn_data = [] # of ConnectionType() # c=IN IP4 192.168.254.54
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+ media = [] # of MediaType() # m=audio 17406 RTP/AVP 0 101
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+
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+
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+class SdpParser:
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+
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+ def __init__(self):
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+ pass
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+
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+ def __del__(self):
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+ pass
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+
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+ def child_init(self, y):
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+ return 0
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+
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+
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+ def ParseSDP(self, msg, args):
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+
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+
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+ sdpBody = SDPBodyMessage()
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+ sdpBody.origin = OriginType()
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+ sdpBody.session_name = None
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+ sdpBody.conn_data = []
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+ sdpBody.media = []
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+
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+ if args.lower().find("application/sdp") >= 0:
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+
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+ SIPMSGLines = []
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+ SDPBodyLines = []
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+
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+ emptyLineCounter = 0
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+ for line in args.splitlines():
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+ if line.strip() == "":
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+ emptyLineCounter += 1
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+ continue
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+
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+ if emptyLineCounter == 0:
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+ SIPMSGLines.append(line)
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+ else:
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+ SDPBodyLines.append(line)
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+
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+ for sdpLine in SDPBodyLines:
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+ sdpType = sdpLine.split("=")[0].lower().strip()
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+ sdpPartLine = sdpLine[2:]
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+ sdpParts = sdpPartLine.split()
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+
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+ if sdpType == "o":
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+ oType = OriginType()
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+ try:
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+ oType.username, oType.sess_id, oType.sess_ver, oType.nettype, oType.addrtype, oType.unicast_addr = sdpParts
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+ oType.RAW_STRING = sdpPartLine.strip()
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+ sdpBody.origin = oType
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+ except:
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+ pass
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+ continue
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+
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+ if sdpType == "s":
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+ sdpBody.session_name = sdpPartLine
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+ continue
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+
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+ if sdpType == "c":
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+ cType = ConnectionType()
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+ cType.nettype, cType.addrtype, cType.connection_addr = sdpParts
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+ cType.RAW_STRING = sdpPartLine.strip()
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+ sdpBody.conn_data.append(cType)
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+ continue
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+
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+ if sdpType == "m":
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+ mType = MediaType()
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+ mType.media = sdpParts[0]
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+ mType.port = sdpParts[1]
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+ mType.proto = sdpParts[2]
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+ mType.fmt = sdpParts[3]
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+ mType.args = " ".join(sdpParts[4:]).strip()
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+ mType.RAW_STRING = sdpPartLine.strip()
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+ sdpBody.media.append(mType)
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+ continue
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+
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+
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+
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+ msg.call_function("append_hf", "X-Mangled--Connection-From: %s:%d\r\n" % (msg.src_address[0], msg.src_address[1]))
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+ msg.call_function("append_hf", "X-Mangled--Contact: %s\r\n" % msg.getHeader("Contact"))
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+ if sdpBody.origin.RAW_STRING is not None:
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+ msg.call_function("append_hf", "X-Mangled--Origin: o=%s\r\n" % sdpBody.origin.RAW_STRING)
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+ if sdpBody.session_name is not None:
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+ msg.call_function("append_hf", "X-Mangled--Session-Name: s=%s\r\n" % sdpBody.session_name)
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+ CLcount=0
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+ for CLine in sdpBody.conn_data:
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+ if CLine.RAW_STRING is not None:
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+ msg.call_function("append_hf", "X-Mangled--Connection-Data-%d: c=%s\r\n" % (CLcount, CLine.RAW_STRING))
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+ CLcount += 1
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+
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+ CMcount=0
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+ for CMline in sdpBody.media:
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+ if CMline.RAW_STRING is not None:
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+ msg.call_function("append_hf", "X-Mangled--Media-Data-%d: m=%s\r\n" % (CMcount, CMline.RAW_STRING))
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+ CMcount += 1
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+
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+ return 1
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+
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+def mod_init():
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+ return SdpParser()
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+
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+```
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+
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+In kamailio.cfg:
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+
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+``` c
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+loadmodule "app_python.so"
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+modparam("app_python", "script_name", "/opt/kamailio/python/sdp.py")
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+modparam("app_python", "mod_init_function", "mod_init")
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+modparam("app_python", "child_init_method", "child_init")
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+```
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+
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+and put in a routing block:
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+
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+``` c
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+python_exec("ParseSDP", $mb);
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+```
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Ken Stowe