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/* packet-rudp.c
* Routines for Reliable UDP Protocol.
* Copyright 2004, Duncan Sargeant <dunc-ethereal@rcpt.to>
*
* $Id$
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Copied from packet-data.c, README.developer, and various other files.
*
* 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.
* Reliable UDP is a lightweight protocol for providing TCP-like flow
* control over UDP. Cisco published an PFC a long time ago, and
* their actual implementation is slightly different, having no
* checksum field.
*
* I've cheated here - RUDP could be used for anything, but I've only
* seen it used to switched telephony calls, so we just call the Cisco SM
* dissector from here.
*
* Here are some links:
*
* http://www.watersprings.org/pub/id/draft-ietf-sigtran-reliable-udp-00.txt
* http://www.javvin.com/protocolRUDP.html
* http://www.cisco.com/univercd/cc/td/doc/product/access/sc/rel7/omts/omts_apb.htm#30052
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include <epan/packet.h>
#include <epan/prefs.h>
/* Disable rudp by default. The previously hardcoded value of
* 7000 (used by Cisco) collides with afs and as the draft states:
* "RUDP doesn't place any restrictions on which UDP port numbers are used.
* Valid port numbers are ports not defined in RFC 1700."
*/
/* FIXME: The proper solution would be to convert this dissector into
* heuristic dissector, but it isn't complete anyway.
*/
static guint udp_port = 0;
void proto_reg_handoff_rudp(void);
static int proto_rudp = -1;
static int hf_rudp_flags = -1;
static int hf_rudp_flags_syn = -1;
static int hf_rudp_flags_ack = -1;
static int hf_rudp_flags_eak = -1;
static int hf_rudp_flags_rst = -1;
static int hf_rudp_flags_nul = -1;
static int hf_rudp_flags_chk = -1;
static int hf_rudp_flags_tcs = -1;
static int hf_rudp_flags_0 = -1;
static int hf_rudp_hlen = -1;
static int hf_rudp_seq = -1;
static int hf_rudp_ack = -1;
static int hf_rudp_cksum = -1;
static gint ett_rudp = -1;
static gint ett_rudp_flags = -1;
static dissector_handle_t sm_handle = NULL;
static dissector_handle_t data_handle = NULL;
static void
dissect_rudp(tvbuff_t *tvb, packet_info *pinfo _U_ , proto_tree *tree)
{
tvbuff_t * next_tvb = NULL;
proto_tree *rudp_tree = NULL, *flags_tree;
proto_item *ti = NULL;
int flags[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
int i;
guint8 hlen;
flags[0] = hf_rudp_flags_syn;
flags[1] = hf_rudp_flags_ack;
flags[2] = hf_rudp_flags_eak;
flags[3] = hf_rudp_flags_rst;
flags[4] = hf_rudp_flags_nul;
flags[5] = hf_rudp_flags_chk;
flags[6] = hf_rudp_flags_tcs;
flags[7] = hf_rudp_flags_0;
hlen = tvb_get_guint8(tvb, 1);
col_set_str(pinfo->cinfo, COL_PROTOCOL, "RUDP");
col_clear(pinfo->cinfo, COL_INFO);
if (tree) {
ti = proto_tree_add_item(tree, proto_rudp, tvb, 0, hlen, FALSE);
rudp_tree = proto_item_add_subtree(ti, ett_rudp);
ti = proto_tree_add_item(rudp_tree, hf_rudp_flags, tvb, 0, 1, FALSE);
flags_tree = proto_item_add_subtree(ti, ett_rudp_flags);
for (i = 0; i < 8; i++)
proto_tree_add_item(flags_tree, flags[i], tvb, 0, 1, FALSE);
proto_tree_add_item(rudp_tree, hf_rudp_hlen, tvb, 1, 1, FALSE);
proto_tree_add_item(rudp_tree, hf_rudp_seq, tvb, 2, 1, FALSE);
proto_tree_add_item(rudp_tree, hf_rudp_ack, tvb, 3, 1, FALSE);
/* If the header is more than 4 bytes the next 2 bytes are the checksum */
if (hlen > 4) {
proto_tree_add_item(rudp_tree, hf_rudp_cksum, tvb, 4, 2, FALSE);
}
/* If we have even more bytes their meaning is unknown - we have seen this
* in live captures */
if (hlen > 6) {
next_tvb = tvb_new_subset(tvb, 6, hlen-6, hlen-6);
call_dissector(data_handle, next_tvb, pinfo, rudp_tree);
}
}
next_tvb = tvb_new_subset_remaining(tvb, hlen);
if (tvb_length(next_tvb) && sm_handle)
call_dissector(sm_handle, next_tvb, pinfo, tree);
}
void
proto_register_rudp(void)
{
static hf_register_info hf[] = {
{ &hf_rudp_flags,
{ "RUDP Header flags", "rudp.flags",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_rudp_flags_syn,
{ "Syn", "rudp.flags.syn",
FT_BOOLEAN, 8, NULL, 0x80,
NULL, HFILL }
},
{ &hf_rudp_flags_ack,
{ "Ack", "rudp.flags.ack",
FT_BOOLEAN, 8, NULL, 0x40,
NULL, HFILL }
},
{ &hf_rudp_flags_eak,
{ "Eak", "rudp.flags.eak",
FT_BOOLEAN, 8, NULL, 0x20,
"Extended Ack", HFILL }
},
{ &hf_rudp_flags_rst,
{ "RST", "rudp.flags.rst",
FT_BOOLEAN, 8, NULL, 0x10,
"Reset flag", HFILL }
},
{ &hf_rudp_flags_nul,
{ "NULL", "rudp.flags.nul",
FT_BOOLEAN, 8, NULL, 0x08,
"Null flag", HFILL }
},
{ &hf_rudp_flags_chk,
{ "CHK", "rudp.flags.chk",
FT_BOOLEAN, 8, NULL, 0x04,
"Checksum is on header or body", HFILL }
},
{ &hf_rudp_flags_tcs,
{ "TCS", "rudp.flags.tcs",
FT_BOOLEAN, 8, NULL, 0x02,
"Transfer Connection System", HFILL }
},
{ &hf_rudp_flags_0,
{ "0", "rudp.flags.0",
FT_BOOLEAN, 8, NULL, 0x01,
NULL, HFILL }
},
{ &hf_rudp_hlen,
{ "Header Length", "rudp.hlen",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
{ &hf_rudp_seq,
{ "Seq", "rudp.seq",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Sequence Number", HFILL }
},
{ &hf_rudp_ack,
{ "Ack", "rudp.ack",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Acknowledgement Number", HFILL }
},
{ &hf_rudp_cksum,
{ "Checksum", "rudp.cksum",
FT_UINT16, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_rudp,
&ett_rudp_flags,
};
proto_rudp = proto_register_protocol (
"Reliable UDP", /* name */
"RUDP", /* short name */
"rudp" /* abbrev */
);
proto_register_field_array(proto_rudp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
{
module_t *rudp_module;
rudp_module = prefs_register_protocol(proto_rudp, proto_reg_handoff_rudp);
prefs_register_uint_preference(rudp_module,
"udp.port",
"UDP port for RUDP",
"Set the UDP port for Reliable UDP traffic",
10,
&udp_port);
}
}
void
proto_reg_handoff_rudp(void) {
static gboolean initialized = FALSE;
static dissector_handle_t rudp_handle;
static guint saved_udp_port;
if (!initialized) {
rudp_handle = create_dissector_handle(dissect_rudp, proto_rudp);
dissector_add_handle("udp.port", rudp_handle); /* for "decode as" */
sm_handle = find_dissector("sm");
data_handle = find_dissector("data");
initialized = TRUE;
} else {
if (saved_udp_port != 0) {
dissector_delete_uint("udp.port", saved_udp_port, rudp_handle);
}
}
if (udp_port != 0) {
dissector_add_uint("udp.port", udp_port, rudp_handle);
}
saved_udp_port = udp_port;
}
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