[Serusers] SER parallel forking

Peter Gradwell peter at gradwell.com
Thu May 20 10:24:14 CEST 2004


Hi,

We're integrating SER and Asterisk and want to use parallel forking
so that calls for sip users to simultaneously call the sip phone and
ser<user>@asterisk.gradwell.net, which will then wait a per-user delay
before answering with the voicemail.

The call does divert, but only after SER's own timer expires.  This
might work ok as a last resort, but really we want the parallel forking
as described above to work so that we can have per-user delays, it may
also make supporting call diverts easier, since Asterisk is good at
stuff like that.

As far as I can tell the main logic for doing the branching (using
append_branch) is very similar to SER's example config file onr.cfg in
the distribution's examples directory.  However I didn't have much luck
with that either!  Our config file is included below.

Any thoughts on how to make this work would be most welcome!

many thanks
peter

=====================================================================
# # $Id: ser.cfg,v 1.21.2.1 2003/07/30 16:46:18 andrei Exp $ #
# simple quick-start config script
#

# ----------- global configuration parameters ------------------------

#debug=3         # debug level (cmd line: -dddddddddd)
#fork=yes
#log_stderror=no	# (cmd line: -E)

/* Uncomment these lines to enter debugging mode */
debug=9
fork=no
log_stderror=yes

check_via=no	# (cmd. line: -v)
dns=yes           # (cmd. line: -r)
rev_dns=no      # (cmd. line: -R)
listen=193.111.200.106
#mhomed=1
port=5060
children=4
fifo="/tmp/ser_fifo"
alias="ser.gradwell.net"
alias="193.111.200.106"
#fifo_db_url="mysql://ser:********@hostingdb/ser"

# ------------------ module loading ----------------------------------

# Uncomment this if you want to use SQL database
#loadmodule "/usr/local/lib/ser/modules/mysql.so"

loadmodule "/usr/local/lib/ser/modules/mysql.so"
loadmodule "/usr/local/lib/ser/modules/sl.so"
loadmodule "/usr/local/lib/ser/modules/tm.so"
loadmodule "/usr/local/lib/ser/modules/rr.so"
loadmodule "/usr/local/lib/ser/modules/maxfwd.so"
loadmodule "/usr/local/lib/ser/modules/usrloc.so"
loadmodule "/usr/local/lib/ser/modules/registrar.so"
#loadmodule "/usr/local/lib/ser/modules/uri.so"
loadmodule "/usr/local/lib/ser/modules/group.so"
loadmodule "/usr/local/lib/ser/modules/acc.so"
loadmodule "/usr/local/lib/ser/modules/textops.so"
loadmodule "/usr/local/lib/ser/modules/domain.so"
#loadmodule "/usr/local/lib/ser/modules/enum.so"
loadmodule "/usr/local/lib/ser/modules/msilo.so"
loadmodule "/usr/local/lib/ser/modules/auth.so"
loadmodule "/usr/local/lib/ser/modules/auth_db.so"
#loadmodule "/usr/local/lib/ser/modules/nathelper.so"
loadmodule "/usr/local/lib/ser/modules/xlog.so"


# Use a private ENUM space [not yet, we just pretend to be the real thing
#modparam("enum","domain_suffix","enum.go-sip.org.")

# We force all the lookup and registrar related stuff to take the domain
# into account.

# Point everything at sip-auth-adm for DB related stuff
modparam("usrloc", "use_domain",   1)
modparam("registrar", "use_domain",   1)
modparam("group", "use_domain",   1)
modparam("auth_db", "use_rpid",   1)
modparam("auth_db", "rpid_column",   "username")

# We do not use persistant storage, this reduces DB overhead,
# however, if we move to a HA pair, then this should be set to 1
# and the seed for generating nonce values must be synchronised.
# NOTE: Actually we HAVE to use 1 anyway as our aliases table is
# in SQL.
modparam("usrloc", "db_mode",   2)
modparam("usrloc","db_url", "mysql://ser:********@hostingdb/ser")
modparam("domain","db_url", "mysql://ser:********@hostingdb/ser")
modparam("domain","db_mode",1)
modparam("group","db_url", "mysql://ser:********@hostingdb/ser")
#modparam("group","db_mode",1)

modparam("auth_db","db_url", "mysql://ser:********@hostingdb/ser")
modparam("auth_db", "calculate_ha1", yes)
modparam("auth_db", "password_column", "password")
#modparam("uri","db_url", "mysql://ser:********@hostingdb/ser")
#modparam("uri","use_uri_table", yes)
modparam("acc","db_url", "mysql://ser:********@hostingdb/ser")
modparam("msilo","db_url","mysql://ser:********@hostingdb/ser")
#modparam("msilo","registrar","sip:registrar at go-sip.com")

modparam("tm", "fr_inv_timer", 15 )
modparam("tm", "fr_timer", 10 )
#modparam("tm", "wt_timer", 2 )


# Useful for some badly behaved clients
modparam("rr", "enable_full_lr", 1)

# Set accounting flags, these are the defaults anyway
modparam("acc", "db_flag", 1)
modparam("acc", "db_missed_flag", 2)

# Nathelpher
#modparam("nathelper", "natping_interval", 10)

# Which flags mean what...
# 1 - account
# 2 - missed call
# 3 - url reqires enum rewrite
# 4 - user has voicemail accessuser has voicemail access
# 5 - user is online
# 6 - inbout call rtp stream should be proxied:
# 7 - outbound call rtp stream should be proxied:
# 8 - set up voicemail in route[3]

# -------------------------  request routing logic -------------------

# main routing logic

route{

	xdbg("*****\n");
	xdbg("***** %rm %ru\n");
	xdbg("*****\n");

	# initial sanity checks -- messages with
	# max_forwards==0, or excessively long requests
	if (!mf_process_maxfwd_header("10")) {
		sl_send_reply("483","Too Many Hops");
		break;
	};
	if (msg:len > max_len) {
		sl_send_reply("513", "Message too big");
		break;
	};

	# we record-route all messages -- to make sure that
	# subsequent messages will go through our proxy; that's
	# particularly good if upstream and downstream entities
	# use different transport protocol
	record_route();	
	# loose-route processing
	if (loose_route()) {
		t_relay();
		break;
	};

	if(method=="BYE"){
		setflag(1);
		t_relay();
		break;
	};

	# if the request is for other domain use UsrLoc
	# (in case, it does not work, use the following command
	# with proper names and addresses in it)
	if ( is_uri_host_local() || uri == myself ) {

		# We want to deal primarily with numbers rather
		# than usernames, this makes life easier in
		# voicemail.
		#
		# Translate any usernames to numbers
		if (method=="REGISTER") {
			# Leaving the domain blank means that the
			# domain from the url will be used.
			if (!www_authorize("","subscriber")) {
				www_challenge("", "1");
				break;
			};

			save("location");
			break;
		};

		log("**** lookup(aliases)\n");
		lookup("aliases");

		# We don't deal with presence at the moment
		if (method=="SUBSCRIBE" || method == "PUBLISH") {
                        	sl_send_reply("503", "Service Unavailable");
			break;
		};

		# Rewriting for other SIP networks...
		if(uri=~"^sip:\*\*.*"){
			# We only want our customer relaying through our servers
			strip(2);
			if (!proxy_authorize("","subscriber")) {
				proxy_challenge("", "1");
				break;
			};

			sl_send_reply("404", "Not Found");
			break;
		};

		if(uri=~"^sip:[0-9][0-9][0-9]@.*" ){
			t_relay_to_udp("asterisk.gradwell.net","5060");
			break;
		};

		if (uri=~"^sip:0.*") {

			if (uri=~"^sip:0.*") {
				if (uri=~"^sip:00.*") {
					strip(2);
				}else{
					strip(1);
					prefix("44");
				};
			};

			route(6);
			break;
		};

		# native SIP destinations are handled using our USRLOC DB
		if (method == "INVITE" || method == "ACK" || method == "MESSAGE") {
			if (uri=~"^sip:\*") {
				t_relay_to_udp("asterisk.gradwell.net","5060");
				break;
			};

			# Request uri is now invalid or in Username  form
			if (lookup("location")) {
				log("*** found in usrloc\n");
				if(method=="MESSAGE"){
					# Remote agent may not accept messages, we juststore them.
					t_on_failure("1");
					t_relay();
					break;
				};

				# they are  online
				setflag(5);
			} else {
				if(method=="MESSAGE"){
					# Remote agent may not accept messages, we juststore them.
        					if (m_store("1")) {
        				         	t_reply("202", "Accepted");
        					}else{
        				         	t_reply("503", "Service Unavailable");
        					};
					break;
				};
			};

			if (!isflagset(5)) {
				log("**** not found in usrloc, diverting to vm\n");
				revert_uri();
				lookup("aliases");
				# User not registered with either username or extension
				# Instant Unavailable voicemail
				acc_db_request("Unavailable - Offline", "missed_calls");
				log("**** lookup(aliases)\n");
				lookup("aliases");
				prefix("ser");
				route(2);	
				break;
			};

			setflag(8);
			route(3);
			break;
		};
	};

	# forward to current uri now; use stateful forwarding; that
	# works reliably even if we forward from TCP to UDP

	route(3);
}

# Our voicemail route.
route[2]{
         append_hf("P-hint: in-route-2\r\n");
         log("IDESK: Route 2, Forwarding to Voicemail\n");
         xdbg("IDESK: method=%rm, r_uri=%ru, cseq=%cs\n");
	rewritehost("asterisk.gradwell.net");
	rewriteport("5060");
	if (!t_relay()) {
		log("Forwarding to Voicemail FAILED\n");
		sl_reply_error();
		break;
	};
	break;
}


# Stateful relaying with NAT if it is needed.
# NOTE: One possibel enhancement here is to do the rtp-proxying via another box
# this would move the traffic away from the ser server completely.

# Nat for outbound from idesk
route[3]{
        	log("IDESK: Route for fixing up outbound\n");

	if (isflagset(8)) {
		# We know where they are, and they have
		# voicemail access, so we fork to their
		# voicemail account.

		append_branch();
		revert_uri();
		log("**** setting up vm branch\n");
		log("**** lookup(aliases)\n");
		lookup("aliases");
		prefix("ser");

		append_hf("P-hint: known-vm \r\n");
		rewritehost("asterisk.gradwell.net");
		rewriteport("5060");
	};

	if (method == "INVITE"){
		if (isflagset(6)) {
      			log("IDESK: Outbound RTP Proxying \n");
			log("failure 1, reply 1\n");
			t_on_failure("1");
			#t_on_reply("1");
		} ;
		if (isflagset(7)){
      			log("IDESK: Inbound RTP Proxying \n");
			log("failure 1, reply 2\n");
			t_on_failure("1");
			#t_on_reply("2");
		} ;
		if (isflagset(5) && !isflagset(6) && !isflagset(7)){
			log("failure 1, reply 3\n");
			t_on_failure("1");
			#t_on_reply("3");
		};
	};

	if (!t_relay()) {
		sl_reply_error();
		break;
	};
}

####
####onreply_route[1]{
####	# Our rtp proxying
####       	log("IDESK: Reply Route for fixing up Outboudn nat\n");
####	if(status=~"4[0-9][0-9].*"){
####		setflag(2);
####	};
####	if(status=~"200.*" && search("application/sdp")){
####		if(src_ip=="192.168.254.27"){
####			route(5);
####		};
####		# If it comes back through this route then it needs natting
####		if (search("application/sdp")){
####			force_rtp_proxy_from("192.168.254.26");
####		};
####	};
####}
####
####onreply_route[2]{
####	# Our rtp proxying
####       	log("IDESK: Reply Route for fixing up Inbound  nat\n");
####	if(status=~"4[0-9][0-9].*"){
####		setflag(2);
####	};
####	if(status=~"200.*" && search("application/sdp")){
####		if(src_ip=="194.130.117.27"){
####			route(5);
####		};
####		# If it comes back through this route then it needs natting
####		if (search("application/sdp")){
####			force_rtp_proxy_from("194.130.117.26");
####		};
####	};
####}

onreply_route[3]{
	# Our rtp proxying
        	log("IDESK: Reply Route for fixing up Inbound  nat\n");
	if(status=~"4[0-9][0-9].*"){
		setflag(2);
	};
	if(status=~"200.*" && search("application/sdp")){
		if(isflagset(5) && ( src_ip == "192.168.254.27" || src_ip 
== "194.130.117.27")){
			route(5);
		};
	};
}

failure_route[1]{
	if(method=="MESSAGE"){
		# Remote agent may not accept messages, we juststore them.
        		if (m_store("1")) {
        	         	t_reply("202", "Accepted");
        		}else{
        	         	t_reply("503", "Service Unavailable");
        		};
		break;
	};
	append_hf("P-hint: missed \r\n");
	setflag(2);
        	append_hf("P-hint: in-reply-route-1\r\n");
        	log("IDESK: Failure Route 1\n");
}

# Account as missed
route[5] {
	log("IDESK: Route 3\n");
	append_hf("P-hint: in-route-3\r\n");
	append_hf("P-hint: missed \r\n");
#	setflag(2);
	acc_db_request("No Answer", "missed_calls");
}

# This is our route out to the PSTN;
route[6]{
	append_hf("P-hint: in-route-4-pstn\r\n");
	# This really is going to be a PSTN call, so we
	# Need to check the credentials
	# Leaving the domain blank means that the
	# domain from the url will be used.

	if (uri=~"^sip:44.*") {
		strip(2);
		prefix("0");
	};

	if(method=="INVITE"){
		# sip.calluk.com will authenticate...
		#if (!proxy_authorize("","subscriber")) {
		#	proxy_challenge("", "1");
		#	break;
		#};
		append_rpid_hf();
		log("Forwarding to PSTN\n");
		setflag(1);
		rewritehost("sip.calluk.com");
		if(!t_relay_to_udp("sip.calluk.com","5060")){
			sl_reply_error();
		};
		break;
	};

	if(method=="CANCEL" || method=="ACK" || method=="BYE"){
		setflag(1);
		if(!t_relay_to_udp("sip.calluk.com","5060")){
			sl_reply_error();
		};
		break;
	}
}

=====================================================================

thanks
peter

-- 
peter gradwell. gradwell dot com Ltd. http://www.gradwell.com/
  -- engineering & hosting services for email, web and voip --
   -- http://www.peter.me.uk/  -- http://www.voip.org.uk/ --




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