/* packet-xot.c
- * Routines for X25 over TCP dissection (RFC 1613)
+ * Routines for X.25 over TCP dissection (RFC 1613)
*
* Copyright 2000, Paul Ionescu <paul@acorp.ro>
*
- * $Id: packet-xot.c,v 1.2 2001/01/03 06:55:34 guy Exp $
+ * $Id: packet-xot.c,v 1.11 2002/08/28 21:00:40 jmayer Exp $
*
* Ethereal - Network traffic analyzer
- * By Gerald Combs <gerald@zing.org>
+ * By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
*
- *
* This program 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.
- *
+ *
* This program 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.
#include <string.h>
#include <glib.h>
-#include "packet.h"
-#include "packet-x25.h"
+#include <epan/packet.h>
+#include "packet-frame.h"
+#include "prefs.h"
#define TCP_PORT_XOT 1998
static gint proto_xot = -1;
+static gint hf_xot_version = -1;
+static gint hf_xot_length = -1;
+
static gint ett_xot = -1;
+/* desegmentation of X.25 over TCP */
+static gboolean xot_desegment = TRUE;
+
+static dissector_handle_t x25_handle;
+
static void dissect_xot(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
+ volatile int offset = 0;
+ int length_remaining;
+ guint16 version;
+ guint16 plen;
+ int length;
proto_item *ti;
proto_tree *xot_tree;
- guint16 version,len;
- tvbuff_t *next_tvb;
-
- CHECK_DISPLAY_AS_DATA(proto_xot, tvb, pinfo, tree);
-
- pinfo->current_proto = "XOT";
- if (check_col(pinfo->fd, COL_PROTOCOL))
- col_set_str(pinfo->fd, COL_PROTOCOL, "XOT");
-
- version = tvb_get_ntohs(tvb,0);
- len = tvb_get_ntohs(tvb,2);
-
- if (check_col(pinfo->fd, COL_INFO))
- col_add_fstr(pinfo->fd, COL_INFO, "XOT Version = %u, size = %u",version,len );
-
- if (tree) {
-
- ti = proto_tree_add_protocol_format(tree, proto_xot, tvb, 0, 4, "X.25 over TCP");
- xot_tree = proto_item_add_subtree(ti, ett_xot);
-
- ti = proto_tree_add_text(xot_tree, tvb, 0,2,"XOT Version : %u %s",version,(version==0?"":" - Unknown version")) ;
- ti = proto_tree_add_text(xot_tree, tvb, 2,2,"XOT length : %u",len) ;
+ tvbuff_t *next_tvb;
+
+ while (tvb_reported_length_remaining(tvb, offset) != 0) {
+ length_remaining = tvb_length_remaining(tvb, offset);
+
+ /*
+ * Can we do reassembly?
+ */
+ if (xot_desegment && pinfo->can_desegment) {
+ /*
+ * Yes - is the X.25-over-TCP header split across segment boundaries?
+ */
+ if (length_remaining < 4) {
+ /*
+ * Yes. Tell the TCP dissector where the data for this message
+ * starts in the data it handed us, and how many
+ * more bytes we need, and return.
+ */
+ pinfo->desegment_offset = offset;
+ pinfo->desegment_len = 4 - length_remaining;
+ return;
+ }
+ }
+
+ /*
+ * Get the length of the XOT packet.
+ */
+ version = tvb_get_ntohs(tvb, offset + 0);
+ if (version != 0)
+ return;
+ plen = tvb_get_ntohs(tvb, offset + 2);
+
+ /*
+ * Can we do reassembly?
+ */
+ if (xot_desegment && pinfo->can_desegment) {
+ /*
+ * Yes - is the XOT packet split across segment boundaries?
+ */
+ if (length_remaining < plen + 4) {
+ /*
+ * Yes. Tell the TCP dissector where the data for this message
+ * starts in the data it handed us, and how many more bytes we
+ * need, and return.
+ */
+ pinfo->desegment_offset = offset;
+ pinfo->desegment_len = (plen + 4) - length_remaining;
+ return;
+ }
+ }
+
+ /*
+ * Dissect the X.25-over-TCP packet.
+ *
+ * Catch the ReportedBoundsError exception; if this particular message
+ * happens to get a ReportedBoundsError exception, that doesn't mean
+ * that we should stop dissecting X.25-over-TCP messages within this
+ * frame or chunk of reassembled data.
+ *
+ * If it gets a BoundsError, we can stop, as there's nothing more to see,
+ * so we just re-throw it.
+ */
+ TRY {
+ if (check_col(pinfo->cinfo, COL_PROTOCOL))
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "XOT");
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_add_fstr(pinfo->cinfo, COL_INFO, "XOT Version = %u, size = %u",
+ version,plen );
+
+ if (tree) {
+ ti = proto_tree_add_protocol_format(tree, proto_xot, tvb, offset, 4,
+ "X.25 over TCP");
+ xot_tree = proto_item_add_subtree(ti, ett_xot);
+
+ proto_tree_add_uint(xot_tree, hf_xot_version, tvb, offset, 2, version);
+ proto_tree_add_uint(xot_tree, hf_xot_length, tvb, offset + 2, 2, plen);
+ }
+
+ /*
+ * Construct a tvbuff containing the amount of the payload we have
+ * available. Make its reported length the amount of data in the
+ * X.25-over-TCP packet.
+ *
+ * XXX - if reassembly isn't enabled. the subdissector will throw a
+ * BoundsError exception, rather than a ReportedBoundsError exception.
+ * We really want a tvbuff where the length is "length", the reported
+ * length is "plen + 4", and the "if the snapshot length were infinite"
+ * length is the minimum of the reported length of the tvbuff handed
+ * to us and "plen+4", with a new type of exception thrown if the offset
+ * is within the reported length but beyond that third length, with that
+ * exception getting the "Unreassembled Packet" error.
+ */
+ length = length_remaining - 4;
+ if (length > plen)
+ length = plen;
+ next_tvb = tvb_new_subset(tvb, offset + 4, length, plen);
+ call_dissector(x25_handle,next_tvb,pinfo,tree);
+ }
+ CATCH(BoundsError) {
+ RETHROW;
+ }
+ CATCH(ReportedBoundsError) {
+ show_reported_bounds_error(tvb, pinfo, tree);
+ }
+ ENDTRY;
+
+ /*
+ * Skip the X.25-over-TCP header and the payload.
+ */
+ offset += plen + 4;
}
- next_tvb = tvb_new_subset(tvb,4, -1 , -1);
- dissect_x25(next_tvb,pinfo,tree);
}
-
+
/* Register the protocol with Ethereal */
-void proto_register_xot(void)
-{
+void
+proto_register_xot(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_xot_version,
+ { "Version", "xot.version", FT_UINT16, BASE_DEC,
+ NULL, 0, "Version of X.25 over TCP protocol", HFILL }},
+
+ { &hf_xot_length,
+ { "Length", "xot.length", FT_UINT16, BASE_DEC,
+ NULL, 0, "Length of X.25 over TCP packet", HFILL }}
+ };
- /* Setup protocol subtree array */
- static gint *ett[] = {
- &ett_xot,
- };
+ static gint *ett[] = {
+ &ett_xot,
+ };
+ module_t *xot_module;
- /* Register the protocol name and description */
- proto_xot = proto_register_protocol("X.25 over TCP", "XOT", "xot");
+ proto_xot = proto_register_protocol("X.25 over TCP", "XOT", "xot");
+ proto_register_field_array(proto_xot, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
- /* Required function calls to register the header fields and subtrees used */
- proto_register_subtree_array(ett, array_length(ett));
-};
+ xot_module = prefs_register_protocol(proto_xot, NULL);
+ prefs_register_bool_preference(xot_module, "desegment",
+ "Desegment all X.25-over-TCP messages spanning multiple TCP segments",
+ "Whether the X.25-over-TCP dissector should desegment all messages spanning multiple TCP segments",
+ &xot_desegment);
+}
void
proto_reg_handoff_xot(void)
{
- dissector_add("tcp.port", TCP_PORT_XOT, dissect_xot);
+ dissector_handle_t xot_handle;
+
+ /*
+ * Get a handle for the X.25 dissector.
+ */
+ x25_handle = find_dissector("x.25");
+
+ xot_handle = create_dissector_handle(dissect_xot, proto_xot);
+ dissector_add("tcp.port", TCP_PORT_XOT, xot_handle);
}
git.samba.org / obnox / wireshark / wip.git / blobdiff