[Users] Re: [openser] Incorrect Route header

[Jeremie Le Hen]

Hi,

On Mon, Aug 28, 2006 at 04:36:42PM +0200, Jeremie Le Hen wrote:
> I am running a NATing proxy.  Everything works fine, except that
> some of my neighbour proxies send me BYE requests with an incorrect
> Route header containing their own IP address.
> 
> The result is naturally that my proxy sends back the request and
> the call is never ended.
> 
> I know this is a wrong behaviour and I have contacted the remote
> administrator to have him fix his proxy.  But in the meantime
> I would like to find a workaround for my users.
> 
> I tried to do the following, before calling loose_routing().  I am
> not sure if it's relevant or not nevertheless:
> 
> % if (method == "BYE") {
> % 	# XXX Remove buggy Route header from BYE packets.
> % 	xlog("L_ALERT", "Removing buggy Route header from BYE request");
> % 	remove_hf("Route");
> % 	lookup("location");
> % }
> 
> 
> However, I raised the verbosity level and found that the Route header
> is read as soon as the packet is received, therefore the above
> block is not really useful.

I dare to post the temporary workaround I have found for this issue,
for the records.

Fortunately, stock OpenSER doesn't allow to do this, which is fine
in regard to the RFC.

However I have customers and I can't afford to wait for the remote
administrator to unbreak his proxy.  Given that the packet is
analyzed as soon as it is received by OpenSER, I didn't find an
easy way to circumvent a buggy Route header using the available
modules.  Therefore, I wrote my little own module "shuntroute.so"
which mangles the SIP message as though there hav been no Route
header at all.

The above configuration block is now:

% if (method == "BYE") {
%     # XXX Remove buggy Route header from BYE packets.
%     xlog("L_ALERT", "Removing buggy Route header from BYE request");
%     shuntroute();
%     remove_hf("Route");
%     lookup("location");
% }


Please purist, forgive me.

Best regards,
-- 
Jeremie Le Hen
< jeremie at le-hen dot org >< ttz at chchile dot org >
-------------- next part --------------
diff -urNp openser-1.1.0-notls/modules/shuntroute/Makefile openser-1.1.0-shuntroute/modules/shuntroute/Makefile
--- openser-1.1.0-notls/modules/shuntroute/Makefile	1970-01-01 01:00:00.000000000 +0100
+++ openser-1.1.0-shuntroute/modules/shuntroute/Makefile	2006-08-29 14:33:42.000000000 +0200
@@ -0,0 +1,6 @@
+include ../../Makefile.defs
+auto_gen=
+NAME=shuntroute.so
+LIBS=
+
+include ../../Makefile.modules
diff -urNp openser-1.1.0-notls/modules/shuntroute/shuntroute.c openser-1.1.0-shuntroute/modules/shuntroute/shuntroute.c
--- openser-1.1.0-notls/modules/shuntroute/shuntroute.c	1970-01-01 01:00:00.000000000 +0100
+++ openser-1.1.0-shuntroute/modules/shuntroute/shuntroute.c	2006-08-29 15:50:39.000000000 +0200
@@ -0,0 +1,80 @@
+/*
+ * $Id: mangler.c,v 1.3 2006/01/24 20:56:25 bogdan_iancu Exp $
+ *
+ * mangler module
+ *
+ * Copyright (C) 2001-2003 FhG Fokus
+ *
+ * This file is part of openser, a free SIP server.
+ *
+ * openser is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version
+ *
+ * openser is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License 
+ * along with this program; if not, write to the Free Software 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * History:
+ * --------
+ *  2003-04-07 first version.  
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "../../sr_module.h"
+#include "../../mem/mem.h"
+#include "../../dprint.h"
+#include "../../ut.h"
+#include "../../error.h"
+#include "../../str.h"
+#include "../../parser/msg_parser.h"    /* struct sip_msg */
+
+MODULE_VERSION
+
+static int shuntroute(struct sip_msg *msg, char *unused1, char *unused2);
+
+/* Exported functions. */
+static cmd_export_t cmds[] = 
+{
+	{"shuntroute", shuntroute, 0, NULL, REQUEST_ROUTE},
+	{0, 0, 0, 0, 0}
+};
+
+/* Module interface. */
+struct module_exports exports = {
+	"shuntroute",
+	cmds,			/* Exported functions */
+	NULL,			/* Exported parameters */
+	NULL,			/* exported statistics */
+	NULL,			/* module initialization function */
+	NULL,			/* response function */
+	NULL,			/* destroy function */
+	NULL			/* child initialization function */
+};
+
+static int
+shuntroute(struct sip_msg *msg,
+	   char *unused1 __attribute__ ((unused)),
+	   char *unused2 __attribute__ ((unused)))
+{
+	struct hdr_field *itr, *tmp;;
+
+	if (msg->route == NULL)
+		return 1;
+	itr = msg->route;
+	while (itr) {
+		tmp = itr->sibling;
+		pkg_free(itr);
+		itr = tmp;
+	}
+	msg->route = NULL;
+	return 1;
+}