I am trying to learn Kamailio to set up a SIP/RTP proxy for WebRTC with FreeSWITCH, and I wanted to use this configuration file template as a starting point.
(Source: https://github.com/havfo/WEBRTC-to-SIP)

But i have the error : ERROR: [core/ppcfg.c:275]: pp_ifdef_level_error(): different number of preprocessor directives: 1 more #!if[n]def as #!endif

I don't understand because I checked and everything seems okay with the if/endif statements to me.

# grep '#!ifndef' kamailio.cfg | wc -l
2
# grep '#!ifdef' kamailio.cfg | wc -l
49
# grep '#!endif' kamailio.cfg | wc -l
51

#!ifdef : 49 occurrences
#!ifndef : 2 occurrences
Total (#!ifdef and #!ifndef) : 51 occurrences
#!endif : 51 occurrences

Is there a problem with the parser or a compatibility problem (i am on 5.6.3) ?

#!KAMAILIO
#

#!define WITH_MYSQL
#!define WITH_AUTH
#!define WITH_USRLOCDB
#!define WITH_TLS
#!define WITH_HOMER
#!define WITH_WEBSOCKETS
#!define WITH_ANTIFLOOD
#!define WITH_IPV6
##!define WITH_BRIDGE_ON_FAIL
#!define WITH_LOCALHOST_WS
##!define WITH_LOCALHOST_SIP

#!substdef "!MY_SIP_PORT!5060!g"
#!substdef "!MY_SIPS_PORT!5061!g"
#!substdef "!MY_WS_PORT!8080!g"
#!substdef "!MY_WSS_PORT!4443!g"

#!substdef "!MY_IP4_ADDR!XXXXX-XXXXX!g"
#!substdef "!IP4_LOCALHOST!127.0.0.1!g"
#!substdef "!MY_WS4_ADDR!tcp:MY_IP4_ADDR:MY_WS_PORT!g"
#!substdef "!MY_WSS4_ADDR!tls:MY_IP4_ADDR:MY_WSS_PORT!g"
#!substdef "!LOCALHOST_WS4_ADDR!tcp:IP4_LOCALHOST:MY_WS_PORT!g"
#!substdef "!LOCALHOST_WSS4_ADDR!tls:IP4_LOCALHOST:MY_WSS_PORT!g"

#!ifdef WITH_IPV6
    #!substdef "!MY_IP6_ADDR![XXXXXX-XXXXXX]!g"
    #!substdef "!IP6_LOCALHOST![::1]!g"
    #!substdef "!MY_WS6_ADDR!tcp:MY_IP6_ADDR:MY_WS_PORT!g"
    #!substdef "!MY_WSS6_ADDR!tls:MY_IP6_ADDR:MY_WSS_PORT!g"
    #!substdef "!LOCALHOST_WS6_ADDR!tcp:IP6_LOCALHOST:MY_WS_PORT!g"
    #!substdef "!LOCALHOST_WSS6_ADDR!tls:IP6_LOCALHOST:MY_WSS_PORT!g"
#!endif

#!substdef "!MY_DOMAIN!XXXX-XXXX!g"

# *** Value defines - IDs used later in config
#!ifdef WITH_MYSQL
    # - database URL - used to connect to database server by modules such
    #		 as: auth_db, acc, usrloc, a.s.o.
    #!ifndef DBURL
        #!define DBURL "mysql://kamailio:kamailiorw@localhost/kamailio"
    #!endif
#!endif

# - flags
#	 FLT_ - per transaction (message) flags
#	FLB_ - per branch flags
#!define FLT_NATS 5

#!define FLB_NATB 6
#!define FLB_NATSIPPING 7
#!define FLB_RTPWS 8
#!define FLB_IPV6 9
#!define FLB_V4V6 10
#!define FLB_BRIDGE 11

####### Global Parameters #########

### LOG Levels: 3=DBG, 2=INFO, 1=NOTICE, 0=WARN, -1=ERR
#!ifdef WITH_DEBUG
    debug=4
    log_stderror=no
#!else
    debug=2
    log_stderror=no
#!endif

memdbg=5
memlog=5

log_facility=LOG_LOCAL0

fork=yes
children=4

port=MY_SIP_PORT
tls_port_no=MY_SIPS_PORT

#!ifdef WITH_TLS
    enable_tls=yes
#!endif


listen=MY_IP4_ADDR
#!ifdef WITH_LOCALHOST_SIP
    listen=IP4_LOCALHOST
#!endif
#!ifdef WITH_IPV6
    listen=MY_IP6_ADDR
    #!ifdef WITH_LOCALHOST_SIP
        listen=IP6_LOCALHOST
    #!endif
#!endif

#!ifdef WITH_WEBSOCKETS
    listen=MY_WS4_ADDR
    #!ifdef WITH_LOCALHOST_WS
        listen=LOCALHOST_WS4_ADDR
    #!endif
    #!ifdef WITH_IPV6
        listen=MY_WS6_ADDR
        #!ifdef WITH_LOCALHOST_WS
            listen=LOCALHOST_WS6_ADDR
        #!endif
    #!endif
    #!ifdef WITH_TLS
        listen=MY_WSS4_ADDR
        #!ifdef WITH_LOCALHOST_WS
            listen=LOCALHOST_WSS4_ADDR
        #!endif
        #!ifdef WITH_IPV6
            listen=MY_WSS6_ADDR
            #!ifdef WITH_LOCALHOST_WS
                listen=LOCALHOST_WSS6_ADDR
            #!endif
        #!endif
    #!endif
#!endif

use_dns_cache = on			# Use KAMAILIO internal DNS cache
use_dns_failover = on		# Depends on KAMAILIO internal DNS cache
dns_srv_loadbalancing = on		#
dns_try_naptr = on			#
dns_retr_time=1			# Time in seconds before retrying a DNS request
dns_retr_no=3				# Number of DNS retransmissions before giving up

# Set protocol preference order - ignore target priority
dns_naptr_ignore_rfc= yes		 # Ignore target NAPTR priority
dns_tls_pref=50			# First priority: TLS
dns_tcp_pref=30			# Second priority: TCP
dns_udp_pref=10			# Third priority: UDP

tcp_connection_lifetime=3604
tcp_accept_no_cl=yes
tcp_rd_buf_size=16384


# set paths to location of modules (to sources or installation folders)
#!ifdef WITH_SRCPATH
    mpath="modules/"
#!else
    mpath="/usr/lib/x86_64-linux-gnu/kamailio/modules/"
#!endif

#!ifdef WITH_MYSQL
    loadmodule "db_mysql.so"
#!endif

loadmodule "kex.so"
loadmodule "corex.so"
loadmodule "tm.so"
loadmodule "tmx.so"
loadmodule "sl.so"
loadmodule "rr.so"
loadmodule "pv.so"
loadmodule "maxfwd.so"
loadmodule "usrloc.so"
loadmodule "registrar.so"
loadmodule "textops.so"
loadmodule "siputils.so"
loadmodule "xlog.so"
loadmodule "sanity.so"
loadmodule "ctl.so"
loadmodule "cfg_rpc.so"
loadmodule "sdpops.so"
loadmodule "textopsx.so"

#!ifdef WITH_AUTH
    loadmodule "auth.so"
    loadmodule "auth_db.so"
    #!ifdef WITH_IPAUTH
        loadmodule "permissions.so"
    #!endif
#!endif

#!ifdef WITH_PRESENCE
    loadmodule "presence.so"
    loadmodule "presence_xml.so"
#!endif

#!ifdef WITH_TLS
    loadmodule "tls.so"
#!endif

#!ifdef WITH_HOMER
    loadmodule "siptrace.so"
#!endif

#!ifdef WITH_WEBSOCKETS
    loadmodule "xhttp.so"
    loadmodule "websocket.so"
    loadmodule "nathelper.so"
    loadmodule "rtpengine.so"
#!endif

#!ifdef WITH_ANTIFLOOD
    loadmodule "htable.so"
    loadmodule "pike.so"
#!endif

#!ifdef WITH_DEBUG
    loadmodule "debugger.so"
#!endif

# ----------------- setting module-specific parameters ---------------


# ----- rr params -----
# add value to ;lr param to cope with most of the UAs
modparam("rr", "enable_full_lr", 1)
# do not append from tag to the RR (no need for this script)
modparam("rr", "append_fromtag", 0)


# ----- registrar params -----
modparam("registrar", "method_filtering", 1)
# max value for expires of registrations
modparam("registrar", "max_expires", 3600)


# ----- usrloc params -----
/* enable DB persistency for location entries */
#!ifdef WITH_USRLOCDB
    modparam("usrloc", "db_url", DBURL)
    modparam("usrloc", "db_mode", 2)
#!endif


# ----- auth_db params -----
#!ifdef WITH_AUTH
    modparam("auth_db", "db_url", DBURL)
    modparam("auth_db", "calculate_ha1", 1)
    modparam("auth_db", "password_column", "password")
    modparam("auth_db", "load_credentials", "")
#!endif

#!ifdef WITH_PRESENCE
    # ----- presence params -----
    modparam("presence", "db_url", DBURL)

    # ----- presence_xml params -----
    modparam("presence_xml", "db_url", DBURL)
    modparam("presence_xml", "force_active", 1)
#!endif


##!ifdef WITH_NAT
    # ----- rtpproxy params -----
    modparam("rtpengine", "rtpengine_sock", "udp:127.0.0.1:22222")
    modparam("rtpengine", "extra_id_pv", "$avp(extra_id)")

    # ----- nathelper params -----
    modparam("nathelper", "natping_interval", 30)
    modparam("nathelper", "ping_nated_only", 1)
    modparam("nathelper", "sipping_bflag", FLB_NATSIPPING)
    modparam("nathelper", "sipping_from", "sip:pinger@XXXX-XXXX")
    modparam("nathelper|registrar", "received_avp", "$avp(RECEIVED)")
    modparam("usrloc", "nat_bflag", FLB_NATB)
##!endif

# ----- corex params -----
modparam("corex", "alias_subdomains", "MY_DOMAIN")

#!ifdef WITH_TLS
    # ----- tls params -----
    modparam("tls", "config", "/etc/kamailio/tls.cfg")
    modparam("tls", "tls_force_run", 1)
#!endif

#!ifdef WITH_WEBSOCKETS
    modparam("nathelper|registrar", "received_avp", "$avp(RECEIVED)")
#!endif

#!ifdef WITH_HOMER
    #Siptrace
    modparam("siptrace", "duplicate_uri", "sip:127.0.0.1:9060")
    modparam("siptrace", "hep_mode_on", 1)
    modparam("siptrace", "trace_to_database", 0)
    modparam("siptrace", "trace_flag", 22)
    modparam("siptrace", "trace_on", 1)
#!endif

#!ifdef WITH_ANTIFLOOD
    # ----- pike params -----
    modparam("pike", "sampling_time_unit", 2)
    modparam("pike", "reqs_density_per_unit", 16)
    modparam("pike", "remove_latency", 4)

    # ----- htable params -----
    # ip ban htable with autoexpire after 5 minutes
    modparam("htable", "htable", "ipban=>size=8;autoexpire=300;")
#!endif

#!ifdef WITH_DEBUG
    # ----- debugger params -----
    modparam("debugger", "cfgtrace", 1)
#!endif

####### Routing Logic ########
request_route {
    #!ifdef WITH_HOMER
	    # start duplicate the SIP message here
	    sip_trace();
	    setflag(22);
    #!endif

	# per request initial checks
	route(REQINIT);

	xlog("L_INFO", "START: $rm from $fu (IP:$si:$sp)\n");

    #!ifdef WITH_WEBSOCKETS
	    if (nat_uac_test(64)) {
		    # Do NAT traversal stuff for requests from a WebSocket
		    # connection - even if it is not behind a NAT!
		    # This won't be needed in the future if Kamailio and the
		    # WebSocket client support Outbound and Path.
		    force_rport();
		    if (is_method("REGISTER")) {
			    fix_nated_register();
		    } else if (!add_contact_alias()) {
			    xlog("L_ERR", "Error aliasing contact <$ct>\n");
			    sl_send_reply("400", "Bad Request");
			    exit;
		    }
	    }
    #!endif

	# NAT detection
	route(NATDETECT);

	# CANCEL processing
	if (is_method("CANCEL")) {
		if (t_check_trans()) {
			route(RELAY);
		}
		exit;
	}

	# handle requests within SIP dialogs
	route(WITHINDLG);

	### only initial requests (no To tag)

	t_check_trans();

	# authentication
	route(AUTH);

	# record routing for dialog forming requests (in case they are routed)
	# - remove preloaded route headers
	remove_hf("Route");
	if (is_method("INVITE|SUBSCRIBE")) {
		record_route();
	}

	# dispatch requests to foreign domains
	route(SIPOUT);

	### requests for my local domains

	# handle presence related requests
	route(PRESENCE);

	# handle registrations
	route(REGISTRAR);

	if ($rU == $null) {
		# request with no Username in RURI
		sl_send_reply("484","Address Incomplete");
		exit;
	}

	# user location service
	route(LOCATION);
}

# Wrapper for relaying requests
route[RELAY] {
	# enable additional event routes for forwarded requests
	# - serial forking, RTP relaying handling, a.s.o.
	if (is_method("INVITE|BYE|SUBSCRIBE|UPDATE")) {
		if (!t_is_set("branch_route")) {
			t_on_branch("MANAGE_BRANCH");
		}
	}

	if (is_method("INVITE|SUBSCRIBE|UPDATE")) {
		if (!t_is_set("onreply_route")) {
			t_on_reply("MANAGE_REPLY");
		}
	}

	if (is_method("INVITE")) {
		if (!t_is_set("failure_route")) {
			t_on_failure("MANAGE_FAILURE");
		}
	}

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

# Per SIP request initial checks
route[REQINIT] {
    #!ifdef WITH_ANTIFLOOD
	    # flood dection from same IP and traffic ban for a while
	    # be sure you exclude checking trusted peers, such as pstn gateways
	    # - local host excluded (e.g., loop to self)
	    if (src_ip != myself) {
		    if ($sht(ipban=>$si) != $null) {
			    # ip is already blocked
			    xdbg("request from blocked IP - $rm from $fu (IP:$si:$sp)\n");
			    exit;
		    }

		    if (!pike_check_req()) {
			    xlog("L_ALERT","ALERT: pike blocking $rm from $fu (IP:$si:$sp)\n");
			    $sht(ipban=>$si) = 1;
			    exit;
		    }
	    }
    #!endif

	if (!mf_process_maxfwd_header("10")) {
		sl_send_reply("483","Too Many Hops");
		exit;
	}

	if (!sanity_check("1511", "7")) {
		xlog("Malformed SIP message from $si:$sp\n");
		exit;
	}
}

# Handle requests within SIP dialogs
route[WITHINDLG] {
	if (has_totag()) {
		# sequential request withing a dialog should
		# take the path determined by record-routing
		if (loose_route()) {
            #!ifdef WITH_WEBSOCKETS
			    if ($du == "") {
				    if (!handle_ruri_alias()) {
					    xlog("L_ERR", "Bad alias <$ru>\n");
					    sl_send_reply("400", "Bad Request");
					    exit;
				    }
			    }
            #!endif
			route(DLGURI);
			if (is_method("ACK")) {
				# ACK is forwarded statelessy
				route(NATMANAGE);
			} else if (is_method("NOTIFY")) {
				# Add Record-Route for in-dialog NOTIFY as per RFC 6665.
				record_route();
			}
			route(RELAY);
		} else {
			if (is_method("SUBSCRIBE") && uri == myself) {
				# in-dialog subscribe requests
				route(PRESENCE);
				exit;
			}
			if (is_method("ACK")) {
				if (t_check_trans()) {
					# no loose-route, but stateful ACK;
					# must be an ACK after a 487
					# or e.g. 404 from upstream server
					route(RELAY);
					exit;
				} else {
					# ACK without matching transaction ... ignore and discard
					exit;
				}
			}
			sl_send_reply("404","Not here");
		}
		exit;
	}
}

# Handle SIP registrations
route[REGISTRAR] {
	if (is_method("REGISTER")) {
		if (isflagset(FLT_NATS)) {
			setbflag(FLB_NATB);
			# uncomment next line to do SIP NAT pinging
			## setbflag(FLB_NATSIPPING);
		}

        #!ifdef WITH_IPV6
		    if (af == INET6) {
			    setbflag(FLB_IPV6);
		    }
        #!endif

		if (!save("location")) {
			sl_reply_error();
		}

		exit;
	}
}

# USER location service
route[LOCATION] {
	if (!lookup("location")) {
		$var(rc) = $rc;
		t_newtran();
		switch ($var(rc)) {
			case -1:
			case -3:
				send_reply("404", "Not Found");
				exit;
			case -2:
				send_reply("405", "Method Not Allowed");
				exit;
		}
	}

	route(RELAY);
	exit;
}

# Presence server route
route[PRESENCE] {
	if (!is_method("PUBLISH|SUBSCRIBE")) {
		return;
	}

	if (is_method("SUBSCRIBE") && $hdr(Event) == "message-summary") {
		# returns here if no voicemail server is configured
		sl_send_reply("404", "No voicemail service");
		exit;
	}

    #!ifdef WITH_PRESENCE
	    if (!t_newtran()) {
		    sl_reply_error();
		    exit;
	    }

	    if (is_method("PUBLISH")) {
		    handle_publish();
		    t_release();
	    } else if (is_method("SUBSCRIBE")) {
		    handle_subscribe();
		    t_release();
	    }
	    exit;
    #!endif

	# if presence enabled, this part will not be executed
	if (is_method("PUBLISH") || $rU == $null) {
		sl_send_reply("404", "Not here");
		exit;
	}
	return;
}

# Authentication route
route[AUTH] {
    #!ifdef WITH_AUTH
	    if (is_method("REGISTER") || from_uri == myself) {
		    # authenticate requests
		    if (!auth_check("$fd", "subscriber", "1")) {
			    auth_challenge("$fd", "0");
			    exit;
		    }
		    # user authenticated - remove auth header
		    if (!is_method("REGISTER|PUBLISH")) {
			    consume_credentials();
		    }
	    }
	    # if caller is not local subscriber, then check if it calls
	    # a local destination, otherwise deny, not an open relay here
	    if (from_uri != myself && uri != myself) {
		    sl_send_reply("403","Not relaying");
		    exit;
	    }
    #!endif
	return;
}

# Caller NAT detection route
route[NATDETECT] {
    #!ifdef WITH_IPV6
	    if(af==INET6) {
		    return;
	    }
    #!endif

	force_rport();
	if (nat_uac_test("19")) {
		if (is_method("REGISTER")) {
			fix_nated_register();
		} else if (is_first_hop()) {
			set_contact_alias();
		}
		setflag(FLT_NATS);
	}
	return;
}

# NAT handling
route[NATMANAGE] {
	if (is_request()) {
		if (has_totag()) {
			if (check_route_param("nat=yes")) {
				setbflag(FLB_NATB);
			}

			if (check_route_param("rtp=bridge")) {
				setbflag(FLB_BRIDGE);
			}

			if (check_route_param("rtp=ws")) {
				setbflag(FLB_RTPWS);
			}

            #!ifdef WITH_IPV6
			    if (check_route_param("rtp=v46")) {
				    setbflag(FLB_V4V6);
			    }
            #!endif
		}
	}

	if (!isbflagset(FLB_BRIDGE)) {
		return;
	}

	if (
		!(isflagset(FLT_NATS)
		|| isbflagset(FLB_NATB)
		|| isbflagset(FLB_RTPWS)
        #!ifdef WITH_IPV6
		    || isbflagset(FLB_V4V6)
        #!endif
	    )
    ) {
		return;
	}

	$xavp(r=>$T_branch_idx) = "replace-origin replace-session-connection";

	if (!nat_uac_test("8")) {
		$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " trust-address";
	}


	if (is_request()) {
		if (!has_totag()) {
			if (!t_is_failure_route()) {
				$avp(extra_id) = @via[1].branch + $T_branch_idx;
				$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " via-branch=extra";
			}
		}
	}

	if (is_reply()) {
		$avp(extra_id) = @via[2].branch + $T_branch_idx;
		$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " via-branch=extra";
	}

    #!ifdef WITH_IPV6
	    if (af == INET && isbflagset(FLB_IPV6)) { # IPv4 --> IPv6
		    $xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " address-family=IP6";
	    } else if (af == INET6 && !isbflagset(FLB_IPV6)) { # IPv6 --> IPv4
		    $xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " address-family=IP4";
	    }
    #!endif

	if (isbflagset(FLB_RTPWS)) {
		if ($proto =~ "ws") { # web --> SIP
			$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " rtcp-mux-demux DTLS=off SDES-off ICE=remove RTP/AVP";
		} else { # SIP --> web
			$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " rtcp-mux-offer generate-mid DTLS=passive SDES-off ICE=force RTP/SAVPF";
		}
	} else {
		if ($proto =~ "ws") { # web --> web
			$xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + " generate-mid DTLS=passive SDES-off ICE=force";
		}
		# else {
			# $xavp(r=>$T_branch_idx) = $xavp(r=>$T_branch_idx) + "";
		# }
	}

	xlog("L_INFO", "NATMANAGE branch_id:$T_branch_idx ruri: $ru, method:$rm, status:$rs, extra_id: $avp(extra_id), rtpengine_manage: $xavp(r=>$T_branch_idx)\n");

	rtpengine_manage($xavp(r=>$T_branch_idx));

	if (is_request()) {
		if (!has_totag()) {
			if (t_is_branch_route()) {
				if (isbflagset(FLB_NATB)) {
					add_rr_param(";nat=yes");
				}

				if (isbflagset(FLB_BRIDGE)) {
					add_rr_param(";rtp=bridge");
				}

				if (isbflagset(FLB_RTPWS)) {
					add_rr_param(";rtp=ws");
				}

                #!ifdef WITH_IPV6
				    if (isbflagset(FLB_V4V6)) {
					    add_rr_param(";rtp=v46");
				    }
                #!endif
			}
		}
	}

	if (is_reply()) {
		if (isbflagset(FLB_NATB)) {
			if (is_first_hop()) {
				if (af == INET) {
					set_contact_alias();
				}
			}
		}
	}
	return;
}

# URI update for dialog requests
route[DLGURI] {
	if (!isdsturiset()) {
		handle_ruri_alias();
	}
	return;
}

# Routing to foreign domains
route[SIPOUT] {
	if (!uri == myself) {
		append_hf("P-hint: outbound\r\n");
		route(RELAY);
	}
}

route[BRIDGING] {
	if (!has_totag()) {
		if ($proto =~ "ws" && !($ru =~ "transport=ws")) { # Coming from WS, NOT to WS
			setbflag(FLB_RTPWS); # Need bridging
		} else if (!($proto =~ "ws") && $ru =~ "transport=ws") { # Coming from NOT WS, going to WS
			setbflag(FLB_RTPWS); # Need bridging
		}

        #!ifdef WITH_IPV6
		    if (af == INET6 && !isbflagset(FLB_IPV6)) {
			    setbflag(FLB_V4V6);
		    } else if(af == INET && isbflagset(FLB_IPV6)) {
			    setbflag(FLB_V4V6);
		    }
        #!endif
	}
}

# manage outgoing branches
branch_route[MANAGE_BRANCH] {
	xlog("L_INFO", "MANAGE_BRANCH: New branch [$T_branch_idx] to $ru\n");

	t_on_branch_failure("rtpengine");

    #!ifndef WITH_BRIDGE_ON_FAIL
	    setbflag(FLB_BRIDGE);
    #!endif

	route(BRIDGING);
	route(NATMANAGE);
}

# manage incoming replies
onreply_route[MANAGE_REPLY] {
	xdbg("incoming reply\n");
	if (status =~ "[12][0-9][0-9]") {
		route(NATMANAGE);
	}
}

# manage failure routing cases
failure_route[MANAGE_FAILURE] {
	xlog("L_INFO", "Failure: $rs");
}

#!ifdef WITH_WEBSOCKETS
    onreply_route {
	    if ((($Rp == MY_WS_PORT || $Rp == MY_WSS_PORT) && !(proto == WS || proto == WSS))) {
		    xlog("L_WARN", "SIP response received on $Rp\n");
		    drop;
	    }

	    if (nat_uac_test(64)) {
		    # Do NAT traversal stuff for replies to a WebSocket connection
		    # - even if it is not behind a NAT!
		    # This won't be needed in the future if Kamailio and the
		    # WebSocket client support Outbound and Path.
		    add_contact_alias();
	    }
    }

    event_route[tm:branch-failure:rtpengine] {
	    xlog("L_INFO", "BRANCH FAILED: $sel(via[1].branch) + $T_branch_idx");

        #!ifdef WITH_BRIDGE_ON_FAIL
	        if (!isbflagset(FLB_BRIDGE) && t_check_status("415|488")) {
		        t_reuse_branch();
		        setbflag(FLB_BRIDGE);
		        xlog("L_INFO", "event_route[branch-failure:rtpengine]: trying again\n");

		        route(RELAY);
	        } else {
		        $avp(extra_id) = @via[1].branch + $T_branch_idx;
		        rtpengine_delete("via-branch=extra");
		        xlog("L_INFO", "event_route[branch-failure:rtpengine]: failed\n");
	        }
        #!else
	        $avp(extra_id) = @via[1].branch + $T_branch_idx;
	        rtpengine_delete("via-branch=extra");
        #!endif
    }

    event_route[xhttp:request] {
	    set_reply_close();
	    set_reply_no_connect();

	    if ($Rp != MY_WS_PORT
            #!ifdef WITH_TLS
		        && $Rp != MY_WSS_PORT
            #!endif
	    ) {
		    xlog("L_WARN", "HTTP request received on $Rp\n");
		    xhttp_reply("403", "Forbidden", "", "");
		    exit;
	    }

	    xlog("L_INFO", "HTTP Request Received\n");

	    if ($hdr(Upgrade) =~ "websocket"
		    && $hdr(Connection) =~ "Upgrade"
		    && $rm =~ "GET"
	    ) {

		    # Validate Host - make sure the client is using the correct
		    # alias for WebSockets
		    if ($hdr(Host) == $null || !is_myself("sip:" + $hdr(Host))) {
			    xlog("L_WARN", "Bad host $hdr(Host)\n");
			    xhttp_reply("403", "Forbidden", "", "");
			    exit;
		    }

		    # Optional... validate Origin - make sure the client is from an
		    # authorised website.	For example,
		    #
		    # if ($hdr(Origin) != "https://example.com"
		    #	&& $hdr(Origin) != "https://example.com") {
		    #	xlog("L_WARN", "Unauthorised client $hdr(Origin)\n");
		    #	xhttp_reply("403", "Forbidden", "", "");
		    #	exit;
		    # }

		    # Optional... perform HTTP authentication

		    # ws_handle_handshake() exits (no further configuration file
		    # processing of the request) when complete.
		    if (ws_handle_handshake()) {
			    # Optional... cache some information about the
			    # successful connection
			    exit;
		    }
	    }

	    xhttp_reply("404", "Not Found", "", "");
    }

    event_route[websocket:closed] {
	    xlog("L_INFO", "WebSocket connection from $si:$sp has closed\n");
    }
#!endif