On Wed, Feb 12, 2003 at 11:46:37PM +0100, Jochen Friedrich wrote:
> this patch updates the SNA dissector code:
Checked in, with one change:
> Index: packet-llc.c
> ===================================================================
> RCS file: /cvsroot/ethereal/packet-llc.c,v
> retrieving revision 1.106
> diff -u -r1.106 packet-llc.c
> --- packet-llc.c 25 Jan 2003 00:06:12 -0000 1.106
> +++ packet-llc.c 12 Feb 2003 22:15:34 -0000
> @@ -65,6 +65,7 @@
>
> static dissector_table_t subdissector_table;
> static dissector_table_t cisco_subdissector_table;
> +static dissector_table_t xid_subdissector_table;
>
> static dissector_handle_t bpdu_handle;
> static dissector_handle_t eth_handle;
> @@ -322,16 +323,26 @@
> );
> }
>
> - next_tvb = tvb_new_subset(tvb, llc_header_len, -1, -1);
> - if (XDLC_IS_INFORMATION(control)) {
> - /* non-SNAP */
> - /* do lookup with the subdissector table */
> - if (!dissector_try_port(subdissector_table, dsap,
> - next_tvb, pinfo, tree)) {
> - call_dissector(data_handle,next_tvb, pinfo, tree);
> + if (tvb_offset_exists(tvb, llc_header_len + 1)) {
> + next_tvb = tvb_new_subset(tvb, llc_header_len, -1, -1);
> + if (XDLC_IS_INFORMATION(control)) {
> + /* non-SNAP */
> + /* do lookup with the subdissector table */
> + if (!dissector_try_port(subdissector_table,
> + dsap, next_tvb, pinfo, tree)) {
> + call_dissector(data_handle,next_tvb,
> + pinfo, tree);
> + }
> + } else if ((control & 0xef) == (XDLC_XID|XDLC_U)) {
> + if (!dissector_try_port(xid_subdissector_table,
> + dsap, next_tvb, pinfo, tree)) {
> + call_dissector(data_handle,next_tvb,
> + pinfo, tree);
> + }
> + } else {
> + call_dissector(data_handle,next_tvb, pinfo,
> + tree);
> }
> - } else {
> - call_dissector(data_handle,next_tvb, pinfo, tree);
> }
> }
> }
I checked for "tvb_remaining_length(tvb, llc_header_len)" instead -
checking "tvb_offset_exists(tvb, llc_header_len + 1)" requires that
there be at least *two* bytes starting at "llc_header_len" (the one at
"llc_header_len" and the one at "llc_header_len + 1"), but one
should be sufficient.
The same should perhaps be done in the SNA dissector:
> + while (tvb_offset_exists(tvb, offset+1)) {
> + len = tvb_get_guint8(tvb, offset+0);
> + if (len) {
> + dissect_control(tvb_new_subset(tvb, offset, len, -1),
> + tree, 1, LT);
> + pad = (len+3) & 0xfffc;
> + if (pad > len)
> + proto_tree_add_text(tree, tvb, offset+len,
> + pad-len, "Padding");
> + offset += pad;
> + } else {
> + return;
> + }
> + }
> }
> + if (tvb_offset_exists(tvb, offset+1))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, 4, -1, -1), pinfo, tree);
> + proto_tree_add_item(tree, hf_sna_nlp_opti_0f_bits, tvb, 2, 2, FALSE);
> + if (tvb_offset_exists(tvb, 5))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, 4, -1, -1), pinfo, tree);
> + if (tvb_offset_exists(tvb, 13))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, 12, -1, -1), pinfo, tree);
> + if (tvb_offset_exists(tvb, 21))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, 20, -1, -1), pinfo, tree);
> + } else {
> + if (tvb_offset_exists(tvb, 13))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, 12, -1, -1), pinfo, tree);
> + while (tvb_offset_exists(tvb, offset+1)) {
> + len = tvb_get_guint8(tvb, offset);
> + type = tvb_get_guint8(tvb, offset+1);
> +
> + if (tvb_offset_exists(tvb, index+1))
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, index, -1, -1),
> + pinfo, parent_tree);
> + if (tvb_offset_exists(tvb, index+1)) {
> + call_dissector(data_handle,
> + tvb_new_subset(tvb, index, -1, -1), pinfo,
> + parent_tree);
> + }
and so on.
