library/MGCP_Templates.ttcn

module MGCP_Templates {

/* MGCP Templates, building on top of MGCP_Types (Osmocom) and SDP_Types from Ericsson.
 *
 * (C) 2017 by Harald Welte <laforge@gnumonks.org>
 * All rights reserved.
 *
 * Released under the terms of GNU General Public License, Version 2 or
 * (at your option) any later version.
 */


	import from MGCP_Types all;
	import from SDP_Types all;

	function f_mgcp_par_append(inout template MgcpParameterList list, template MgcpParameter par) {
		var integer len := lengthof(list);
		list[len] := par;
	}

	/* 3.2.2.6 Connection Mode (sendonly, recvonly, sendrecv, confrnce, inactive, loopback,
	 * conttest, netwloop, netwtest) */
	template MgcpParameter t_MgcpParConnMode(template MgcpConnectionMode mode) := { "M", mode };

	/* 3.2.2.2 CallId: maximum 32 hex chars */
	template MgcpParameter ts_MgcpParCallId(MgcpCallId cid) := {
		code := "C",
		val := hex2str(cid)
	};

	/* 3.2.2.18 RequestIdentifier: Maximum 32 hex chars */
	template MgcpParameter ts_MgcpParReqId(MgcpRequestId rid) := {
		code := "X",
		val := hex2str(rid)
	};

	/* 3.2.2.10: LocalConnectionOptions (codec, packetization, bandwidth, ToS, eco, gain, silence, ...) */
	template MgcpParameter t_MgcpParLocConnOpt(template charstring lco) := { "L", lco };

	/* 3.2.2.5: ConnectionId: maximum 32 hex chars */
	template MgcpParameter ts_MgcpParConnectionId(MgcpConnectionId cid) := {
		code := "I",
		val := hex2str(cid)
	};

	/* osmo-bsc_mgcp implements L/C/M/X only, osmo-mgw adds 'I' */
	/* SDP: osmo-bsc_mgcp implements Tx of v,o,s,c,t,m,a */

	template MgcpResponse tr_MgcpResp_Err(template MgcpResponseCode code) := {
		line := {
			code := code,
			trans_id := ?,
			string := ?
		},
		params := {},
		sdp := omit
	}

	template MgcpCommandLine t_MgcpCmdLine(template charstring verb, template MgcpTransId trans_id, template charstring ep) := {
		verb := verb,
		trans_id := trans_id,
		ep := ep,
		ver := "1.0"
	};

	template MgcpCommand ts_CRCX(MgcpTransId trans_id, charstring ep, MgcpConnectionMode mode, MgcpCallId call_id, template SDP_Message sdp := omit) := {
		line := t_MgcpCmdLine("CRCX", trans_id, ep),
		params := {
			t_MgcpParConnMode(mode),
			ts_MgcpParCallId(call_id),
			//t_MgcpParReqId(omit),
			t_MgcpParLocConnOpt("p:20, a:AMR")
		},
		sdp := sdp
	}

	template MgcpCommand tr_CRCX := {
		line := t_MgcpCmdLine("CRCX", ?, ?),
		params := *,
		sdp := *
	}

	template MgcpResponse tr_CRCX_ACK := {
		line := {
			code := "200",
			trans_id := ?,
			string := "OK"
		},
		params:= { { "I", ? }, *},
		sdp := ?
	}

	template MgcpResponse ts_CRCX_ACK(MgcpTransId trans_id, MgcpConnectionId conn_id, template SDP_Message sdp := omit) := {
		line := {
			code := "200",
			trans_id := trans_id,
			string := "OK"
		},
		params:= { ts_MgcpParConnectionId(conn_id) },
		sdp := sdp
	}

	template MgcpCommand ts_MDCX(MgcpTransId trans_id, charstring ep, MgcpConnectionMode mode, MgcpCallId call_id, MgcpConnectionId conn_id, template SDP_Message sdp := omit) := {
		line := t_MgcpCmdLine("MDCX", trans_id, ep),
		params := {
			t_MgcpParConnMode(mode),
			ts_MgcpParCallId(call_id),
			ts_MgcpParConnectionId(conn_id),
			//t_MgcpParReqId(omit),
			t_MgcpParLocConnOpt("p:20, a:AMR")
		},
		sdp := sdp
	}

	template MgcpCommand tr_MDCX := {
		line := t_MgcpCmdLine("MDCX", ?, ?),
		params := *,
		sdp := *
	}

	template MgcpResponse ts_MDCX_ACK(MgcpTransId trans_id, MgcpConnectionId conn_id, template SDP_Message sdp := omit) := ts_CRCX_ACK(trans_id, conn_id, sdp);

	/* have a function that generates a template, rather than a template in order to handle
	 * optional parameters */
	function ts_DLCX(MgcpTransId trans_id, charstring ep, template MgcpCallId call_id := omit,
			 template MgcpConnectionId conn_id := omit) return template MgcpCommand {
		var template MgcpCommand cmd;
		cmd.line := t_MgcpCmdLine("DLCX", trans_id, ep);
		cmd.params := {};
		cmd.sdp := omit;
		if (isvalue(call_id)) {
			f_mgcp_par_append(cmd.params, ts_MgcpParCallId(valueof(call_id)));
			if (isvalue(conn_id)) {
				f_mgcp_par_append(cmd.params, ts_MgcpParConnectionId(valueof(conn_id)));
			}
		}
		return cmd;
	}

	template MgcpCommand tr_DLCX(template MgcpEndpoint ep := ?) := {
		line := t_MgcpCmdLine("DLCX", ?, ep),
		params := *,
		sdp := *
	}

	template MgcpResponse tr_DLCX_ACK := {
		line := {
			code := ("200", "250"),
			trans_id := ?,
			string := "OK"
		},
		params:= *,
		sdp := *
	}

	template MgcpResponse ts_DLCX_ACK2(MgcpTransId trans_id) := {
		line := {
			code := "250",
			trans_id := trans_id,
			string := "OK"
		},
		params:= { /* list of ConnectionIDs */ },
		sdp := omit
	}



	template MgcpResponse ts_DLCX_ACK(MgcpTransId trans_id, MgcpConnectionId conn_id, template SDP_Message sdp := omit) := ts_CRCX_ACK(trans_id, conn_id, sdp);

	template MgcpCommand tr_RSIP := {
		line := t_MgcpCmdLine("RSIP", ?, ?),
		params := *,
		sdp := *
	}

	/* SDP Templates */
	template SDP_Origin ts_SDP_origin(charstring addr, charstring session_id,
					  charstring session_version := "1",
					  charstring addr_type := "IP4",
					  charstring user_name := "-") := {
		user_name := user_name,
		session_id := session_id,
		session_version := session_version,
		net_type := "IN",
		addr_type := addr_type,
		addr := addr
	}

	template SDP_connection ts_SDP_connection_IP(charstring addr, charstring addr_type := "IP4",
						     template integer ttl := omit,
						     template integer num_of_addr := omit) :={
		net_type := "IN",
		addr_type := addr_type,
		conn_addr := {
			addr := addr,
			ttl := ttl,
			num_of_addr := num_of_addr
		}
	}

	template SDP_time ts_SDP_time(charstring beg, charstring end) := {
		time_field := {
			start_time := beg,
			stop_time := end
		},
		time_repeat := omit
	}

	template SDP_media_desc ts_SDP_media_desc(integer port_number, SDP_fmt_list fmts,
						  SDP_attribute_list attributes) := {
		media_field := {
			media := "audio",
			ports := {
				port_number := port_number,
				num_of_ports := omit
			},
			transport := "RTP/AVP",
			fmts := fmts
		},
		information := omit,
		connections := omit,
		bandwidth := omit,
		key := omit,
		attributes := attributes
	}

	/* master template for generating SDP based in template arguments */
	template SDP_Message ts_SDP(charstring local_addr, charstring remote_addr,
				    charstring session_id, charstring session_version,
				    integer rtp_port, SDP_fmt_list fmts,
				    SDP_attribute_list attributes) := {
		protocol_version := 0,
		origin := ts_SDP_origin(local_addr, session_id, session_version),
		session_name := "-",
		information := omit,
		uri := omit,
		emails := omit,
		phone_numbers := omit,
		connection := ts_SDP_connection_IP(remote_addr),
		bandwidth := omit,
		times := { ts_SDP_time("0","0") },
		timezone_adjustments := omit,
		key := omit,
		attributes := omit,
		media_list := { ts_SDP_media_desc(rtp_port, fmts, attributes) }
	}

	template SDP_attribute ts_SDP_rtpmap(integer fmt, charstring val) := {
		rtpmap := {
			attr_value := int2str(fmt) & " " & val
		}
	}
	template SDP_attribute ts_SDP_ptime(integer p) := {
		ptime := {
			attr_value := int2str(p)
		}
	}

	function f_mgcp_extract_par(MgcpMessage msg, MgcpInfoCode code) return charstring {
		var MgcpParameterList pars;
		if (ischosen(msg.command)) {
			pars := msg.command.params;
		} else {
			pars := msg.response.params;
		}
		for (var integer i := 0; i < lengthof(pars); i := i + 1) {
			var MgcpParameter par := pars[i];
			if (par.code == code) {
				return par.val;
			}
		}
		setverdict(fail);
		return "";
	}

	function f_MgcpResp_extract_conn_id(MgcpResponse resp) return MgcpConnectionId {
		var MgcpMessage msg := {
			response := resp
		}
		return str2hex(f_mgcp_extract_par(msg, "I"));
	}

	function f_MgcpCmd_extract_call_id(MgcpCommand cmd) return MgcpCallId {
		var MgcpMessage msg := {
			command := cmd
		}
		return str2hex(f_mgcp_extract_par(msg, "C"));
	}

	function f_mgcp_alloc_tid() return MgcpTransId {
		return int2str(float2int(rnd()*2147483647.0));
	}

	function f_mgcp_alloc_call_id() return MgcpCallId {
		return int2hex(float2int(rnd()*2147483647.0), 8);
	}

	function f_mgcp_alloc_conn_id() return MgcpConnectionId {
		return int2hex(float2int(rnd()*2147483647.0), 8);
	}

	/* those verbs that related to a connection (and hence have ConnectionId) */
	template MgcpVerb tr_MgcpVerb_ConnectionOriented := ("CRCX", "MDCX", "DLCX", "AUCX");
	/* entire command template matching only connection oriented verbs */
	template MgcpCommand tr_MgcpCommand_CO := {
		line := {
			verb := tr_MgcpVerb_ConnectionOriented,
			trans_id := ?,
			ep := ?,
			ver := ?
		},
		params := *,
		sdp := *
	}


}