On Wed, Aug 12, 2009 at 07:14:05PM +0200, Jochen Bartl wrote:
> I have spent the last 2 days with adding IPv6, Stub Routing and
> Authentication TLV support to the EIGRP dissector.
> A lot of the proto_tree_add_text calls were replaced by
> proto_tree_add_item, to make use of the display filter functionality.
So much for letting my half finished ipv6 and hf_ication changes lying in
my local tree. Nevertheless, I had only replaced the text stuff in half of
the functions and IPv6, so yours is more complete. The only thing my dissector
did that yours doesn't was that I added a *hack* to proto.c to allow me
to filter for the prefix' content (included for *informational purposes*
below) by adding an element of type FT_IPv6.
My usage looked like this:
length=tvb_get_guint8(tvb, offset);
ti = proto_tree_add_item(tree, hf_ipv6_int_prefixlen , tvb, offset, 1, FALSE);
offset++;
addr_len=ipv6_addr_and_mask(tvb, offset, &ipv6_addr, length);
if (addr_len < 0) {
proto_item_append_text(ti," [Invalid prefix length %u > 128]", length);
addr_len = 1; /* assure we can exit the loop */
} else {
ti = proto_tree_add_item(tree, hf_ipv6_int_dest, tvb, offset, addr_len, FALSE);
...
{ &hf_ipv6_int_dest,
{ "Destination", "eigrp.ipv6int.dest", FT_IPv6, BASE_NONE, NULL, 0x0,
NULL, HFILL }},
Which brings me to the core of my posting: What would be a good solution
to the ipv6 prefix situation, where only the masklength and the beginning bytes
of an address are put into the packet but I still want to be able to filter
on the address part and maybe even have the resolving stuff available?
Would something like my hack be OK or should we add a new type like FT_IPv6PRE
or something else?
Thanks
Joerg
Index: proto.c
===================================================================
--- proto.c (revision 29361)
+++ proto.c (working copy)
@@ -181,7 +181,7 @@
static void
proto_tree_set_ipv6(field_info *fi, const guint8* value_ptr);
static void
-proto_tree_set_ipv6_tvb(field_info *fi, tvbuff_t *tvb, gint start);
+proto_tree_set_ipv6_tvb(field_info *fi, tvbuff_t *tvb, gint start, gint length);
static void
proto_tree_set_guid(field_info *fi, const e_guid_t *value_ptr);
static void
@@ -1030,6 +1030,7 @@
break;
default:
+assert(0);
DISSECTOR_ASSERT_NOT_REACHED();
value = 0;
break;
@@ -1202,8 +1203,8 @@
break;
case FT_IPv6:
- DISSECTOR_ASSERT(length == 16);
- proto_tree_set_ipv6_tvb(new_fi, tvb, start);
+ DISSECTOR_ASSERT(length >=0 && length <= 16);
+ proto_tree_set_ipv6_tvb(new_fi, tvb, start, length);
break;
case FT_ETHER:
@@ -1856,9 +1857,9 @@
}
static void
-proto_tree_set_ipv6_tvb(field_info *fi, tvbuff_t *tvb, gint start)
+proto_tree_set_ipv6_tvb(field_info *fi, tvbuff_t *tvb, gint start, gint length)
{
- proto_tree_set_ipv6(fi, tvb_get_ptr(tvb, start, 16));
+ proto_tree_set_ipv6(fi, tvb_get_ptr(tvb, start, length));
}
/* Add a FT_GUID to a proto_tree */
