- Nathelper configuration example.

etc/nathelper.cfg

@@ -0,0 +1,227 @@
+#
+# $Id$
+#
+# simple quick-start config script including nathelper support
+
+# This default script includes nathelper support. To make it work
+# you will also have to install Maxim's RTP proxy. The proxy is enforced
+# if one of the parties is behind a NAT.
+#
+# If you have an endpoing in the public internet which is known to
+# support symmetric RTP (Cisco PSTN gateway or voicemail, for example),
+# then you don't have to force RTP proxy. If you don't want to enforce
+# RTP proxy for some destinations than simply use t_relay() instead of
+# route(1)
+#
+# Sections marked with !! Nathelper contain modifications for nathelper
+#
+# NOTE !! This config is EXPERIMENTAL !
+#
+# ----------- 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 
+fork=no
+log_stderror=yes
+*/
+
+check_via=no	# (cmd. line: -v)
+dns=no           # (cmd. line: -r)
+rev_dns=no      # (cmd. line: -R)
+port=5060
+children=4
+fifo="/tmp/ser_fifo"
+
+# ------------------ 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/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/textops.so"
+
+# Uncomment this if you want digest authentication
+# mysql.so must be loaded !
+#loadmodule "/usr/local/lib/ser/modules/auth.so"
+#loadmodule "/usr/local/lib/ser/modules/auth_db.so"
+
+# !! Nathelper
+loadmodule "/usr/local/lib/ser/modules/nathelper.so"
+
+# ----------------- setting module-specific parameters ---------------
+
+# -- usrloc params --
+
+modparam("usrloc", "db_mode",   0)
+
+# Uncomment this if you want to use SQL database 
+# for persistent storage and comment the previous line
+#modparam("usrloc", "db_mode", 2)
+
+# -- auth params --
+# Uncomment if you are using auth module
+#
+#modparam("auth_db", "calculate_ha1", yes)
+#
+# If you set "calculate_ha1" parameter to yes (which true in this config), 
+# uncomment also the following parameter)
+#
+#modparam("auth_db", "password_column", "password")
+
+# -- rr params --
+# add value to ;lr param to make some broken UAs happy
+modparam("rr", "enable_full_lr", 1)
+
+# !! Nathelper
+modparam("registrar", "nat_flag", 6)
+modparam("nathelper", "natping_interval", 30) # Ping interval 30 s
+modparam("nathelper", "ping_nated_only", 1)   # Ping only clients behind NAT
+
+# -------------------------  request routing logic -------------------
+
+# main routing logic
+
+route{
+
+	# 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;
+	};
+
+        # !! Nathelper
+	# Special handling for NATed clients; first, NAT test is
+	# executed: it looks for via!=received and RFC1918 addresses
+	# in Contact (may fail if line-folding is used); also,
+	# the received test should, if completed, should check all
+	# vias for rpesence of received
+	if (nat_uac_test("3")) {
+		# Allow RR-ed requests, as these may indicate that
+		# a NAT-enabled proxy takes care of it; unless it is
+		# a REGISTER
+
+		if (method == "REGISTER" || ! search("^Record-Route:")) {
+		    log("LOG: Someone trying to register from private IP, rewriting\n");
+
+		    # This will work only for user agents that support symmetric
+		    # communication. We tested quite many of them and majority is
+		    # smart enough to be symmetric. In some phones it takes a configuration
+		    # option. With Cisco 7960, it is called NAT_Enable=Yes, with kphone it is
+		    # called "symmetric media" and "symmetric signalling".
+
+		    fix_nated_contact(); # Rewrite contact with source IP of signalling
+		    if (method == "INVITE") {
+		        fix_nated_sdp("1"); # Add direction=active to SDP
+		    };
+		    force_rport(); # Add rport parameter to topmost Via
+		    setflag(6);    # Mark as NATed
+		};
+	};
+
+	# 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
+	if (!method=="REGISTER") record_route();	
+
+	# subsequent messages withing a dialog should take the
+	# path determined by record-routing
+	if (loose_route()) {
+		# mark routing logic in request
+		append_hf("P-hint: rr-enforced\r\n"); 
+		route(1);
+		break;
+	};
+
+	if (!uri==myself) {
+		# mark routing logic in request
+		append_hf("P-hint: outbound\r\n"); 
+		route(1);
+		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 (uri==myself) {
+
+		if (method=="REGISTER") {
+
+# Uncomment this if you want to use digest authentication
+#			if (!www_authorize("iptel.org", "subscriber")) {
+#				www_challenge("iptel.org", "0");
+#				break;
+#			};
+
+			save("location");
+			break;
+		};
+
+		lookup("aliases");
+		if (!uri==myself) {
+			append_hf("P-hint: outbound alias\r\n"); 
+			route(1);
+			break;
+		};
+
+		# native SIP destinations are handled using our USRLOC DB
+		if (!lookup("location")) {
+			sl_send_reply("404", "Not Found");
+			break;
+		};
+	};
+	append_hf("P-hint: usrloc applied\r\n"); 
+	route(1);
+}
+
+route[1] 
+{
+	# !! Nathelper
+	if (uri=~"[@:](192\.168\.|10\.|172\.(1[6-9]|2[0-9]|3[0-1])\.)" && !search("^Route:")){
+	    sl_send_reply("479", "We don't forward to private IP addresses");
+	    break;
+        };
+	
+	# if client or server know to be behind a NAT, enable relay
+	if (isflagset(6)) {
+	    force_rtp_proxy();
+	};
+
+	# NAT processing of replies; apply to all transactions (for example,
+	# re-INVITEs from public to private UA are hard to identify as
+	# NATed at the moment of request processing); look at replies
+	t_on_reply("1");
+
+	# send it out now; use stateful forwarding as it works reliably
+	# even for UDP2TCP
+	if (!t_relay()) {
+		sl_reply_error();
+	};
+}
+
+# !! Nathelper
+onreply_route[1] {
+    # NATed transaction ?
+    if (isflagset(6) && status =~ "(183)|2[0-9][0-9]") {
+        fix_nated_contact();
+	force_rtp_proxy();
+    # otherwise, is it a transaction behind a NAT and we did not
+    # know at time of request processing ? (RFC1918 contacts)
+    } else if (nat_uac_test("1")) {
+        fix_nated_contact();
+    };
+}
+