Ethereal-dev: Re: [Ethereal-dev] IPv6 over MPLS coding

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

From: Hamish Moffatt <hamish@xxxxxxxxxxxx>
Date: Thu, 8 Nov 2001 22:49:48 +1100
On Wed, Nov 07, 2001 at 04:30:58PM -0500, Ashok Narayanan wrote:
> On Thu, 8 Nov 2001 08:27:30 +1100, Hamish Moffatt <hamish@xxxxxxxxxxxx> wrote:
> > I concur. Do you think that looking at the IP version field
> > (as in my patch) is better than just assuming IPv4?
> 
> Yeah, I guess. Gives us a 1-in-8 chance to get it right, instead of just
> blindly assuming.

My thoughts exactly. Can somebody check it in?


thanks,
Hamish
-- 
Hamish Moffatt VK3SB <hamish@xxxxxxxxxx> <hamish@xxxxxxxxxxxx>
Index: packet-mpls.c
===================================================================
RCS file: /cvsroot/ethereal/packet-mpls.c,v
retrieving revision 1.21
diff -u -r1.21 packet-mpls.c
--- packet-mpls.c	2001/06/18 02:17:49	1.21
+++ packet-mpls.c	2001/11/07 12:38:36
@@ -108,7 +108,8 @@
       "", HFILL }},
 };
 
-static dissector_handle_t ip_handle;
+static dissector_handle_t ipv4_handle;
+static dissector_handle_t ipv6_handle;
 
 /*
  * Given a 4-byte MPLS label starting at offset "offset", in tvbuff "tvb",
@@ -138,6 +139,7 @@
     guint8 exp;
     guint8 bos;
     guint8 ttl;
+    guint8 ipvers;
 
     proto_tree  *mpls_tree;
     proto_item  *ti;
@@ -180,7 +182,13 @@
 	if (bos) break;
     }
     next_tvb = tvb_new_subset(tvb, offset, -1, -1);
-    call_dissector(ip_handle, next_tvb, pinfo, tree);
+
+    ipvers = (tvb_get_guint8(tvb, offset) >> 4) & 0x0F;
+    if (ipvers == 6) {
+	call_dissector(ipv6_handle, next_tvb, pinfo, tree);
+    } else {
+        call_dissector(ipv4_handle, next_tvb, pinfo, tree);
+    }
 }
 
 void
@@ -200,9 +208,10 @@
 proto_reg_handoff_mpls(void)
 {
 	/*
-	 * Get a handle for the IP dissector.
+	 * Get a handle for the IPv4 and IPv6 dissectors.
 	 */
-	ip_handle = find_dissector("ip");
+	ipv4_handle = find_dissector("ip");
+	ipv6_handle = find_dissector("ipv6");
 
 	dissector_add("ethertype", ETHERTYPE_MPLS, dissect_mpls, proto_mpls);
 	dissector_add("ppp.protocol", PPP_MPLS_UNI, dissect_mpls, proto_mpls);