![Anders Broman](/assets/img/avatar_default.png)
When offset parameter is 0 replace tvb_bytes_exist() with the faster tvb_length(). non heuristic dissectors svn path=/trunk/; revision=23405
322 lines
8.4 KiB
C
322 lines
8.4 KiB
C
/* packet-epmd.c
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* dissector for EPMD (Erlang Port Mapper Daemon) messages;
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* this are the messages sent between Erlang nodes and
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* the empd process.
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* The message formats are derived from the
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* lib/kernel/src/erl_epmd.* files as part of the Erlang
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* distribution available from http://www.erlang.org/
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*
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* (c) 2007 Joost Yervante Damad <joost[AT]teluna.org>
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald[AT]wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-time.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <epan/packet.h>
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#include <epan/ptvcursor.h>
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static int proto_epmd = -1;
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static int hf_epmd_len = -1;
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static int hf_epmd_type = -1;
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static int hf_epmd_tcp_port = -1;
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static int hf_epmd_dist_high = -1;
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static int hf_epmd_dist_low = -1;
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static int hf_epmd_name_len = -1;
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static int hf_epmd_name = -1;
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static int hf_epmd_elen = -1;
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static int hf_epmd_edata = -1;
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static int hf_epmd_names = -1;
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static int hf_epmd_result = -1;
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static int hf_epmd_creation = -1;
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static gint ett_epmd = -1;
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#define EPMD_PORT 4369
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/* requests */
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#define EPMD_ALIVE2 'x'
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#define EPMD_PORT_PLEASE 'p'
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#define EPMD_PORT_PLEASE2 'z'
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#define EPMD_NAMES 'n'
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#define EPMD_ALIVE 'a'
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/* responses */
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#define EPMD_ALIVE_OK 'Y'
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#define EPMD_ALIVE2_OK 'y'
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#define EPMD_PORT_PLEASE2_OK 'w'
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/* unknown; currently not implemented */
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#define EPMD_DUMP 'd'
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#define EPMD_KILL 'k'
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#define EPMD_STOP 's'
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static const value_string message_types[] =
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{
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{ EPMD_ALIVE, "Alive" },
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{ EPMD_PORT_PLEASE, "Port Please" },
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{ EPMD_NAMES, "Names" },
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{ EPMD_DUMP, "Dump" },
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{ EPMD_KILL, "Kill" },
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{ EPMD_STOP, "Stop" },
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{ EPMD_ALIVE_OK, "Alive Ok" },
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{ EPMD_ALIVE2, "Alive 2" },
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{ EPMD_PORT_PLEASE2, "Port Please 2" },
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{ EPMD_ALIVE2_OK, "Alive 2 Ok" },
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{ EPMD_PORT_PLEASE2_OK, "Port Please 2 Ok" },
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{ 0, NULL }
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};
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static void
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dissect_epmd_request(ptvcursor_t *cursor)
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{
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tvbuff_t *tvb;
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guint8 type;
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tvb = ptvcursor_tvbuff(cursor);
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ptvcursor_add(cursor, hf_epmd_len, 2, FALSE);
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type = tvb_get_guint8(tvb, ptvcursor_current_offset(cursor));
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ptvcursor_add(cursor, hf_epmd_type, 1, FALSE);
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switch (type) {
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case EPMD_ALIVE2: {
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guint16 name_length, elen;
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ptvcursor_add(cursor, hf_epmd_tcp_port, 2, FALSE);
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ptvcursor_advance(cursor,2); /* 'M', 0 */
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ptvcursor_add(cursor, hf_epmd_dist_high, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_dist_low, 2, FALSE);
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name_length = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
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ptvcursor_add(cursor, hf_epmd_name_len, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_name, name_length, FALSE);
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elen = tvb_get_ntohs(tvb, ptvcursor_current_offset(cursor));
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ptvcursor_add(cursor, hf_epmd_elen, 2, FALSE);
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if (elen > 0)
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ptvcursor_add(cursor, hf_epmd_edata, elen, FALSE);
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break;
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}
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case EPMD_PORT_PLEASE:
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case EPMD_PORT_PLEASE2:
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/*ptvcursor_add(cursor, hf_epmd_name, tvb_length(tvb)-3, FALSE);*/
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ptvcursor_add(cursor, hf_epmd_name, -1, FALSE);
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break;
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case EPMD_ALIVE: {
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ptvcursor_add(cursor, hf_epmd_tcp_port, 2, FALSE);
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/*ptvcursor_add(cursor, hf_epmd_name, tvb_length(tvb)-3, FALSE);*/
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ptvcursor_add(cursor, hf_epmd_name, -1, FALSE);
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break;
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}
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case EPMD_NAMES:
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default:
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break;
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}
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}
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static void
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dissect_epmd_response_names(ptvcursor_t *cursor)
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{
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ptvcursor_add(cursor, hf_epmd_tcp_port, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_names, -1, FALSE);
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/* TODO: parse names */
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}
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static void
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dissect_epmd_response(ptvcursor_t *cursor)
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{
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tvbuff_t *tvb;
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guint32 port;
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guint8 type;
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tvb = ptvcursor_tvbuff(cursor);
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port = tvb_get_ntohl(tvb, 0);
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if (port == EPMD_PORT) {
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dissect_epmd_response_names(cursor);
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return;
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}
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type = tvb_get_guint8(tvb, 0);
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ptvcursor_add(cursor, hf_epmd_type, 1, FALSE);
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switch (type) {
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case EPMD_PORT_PLEASE2_OK: {
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ptvcursor_advance(cursor, 1);
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/* 'w', 0, Port(16), Type(8), Proto(8), High(16), Low(16), NLen(16), Name(x) */
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ptvcursor_add(cursor, hf_epmd_tcp_port, 2, FALSE);
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ptvcursor_advance(cursor, 2); /* 'M', 0 */
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ptvcursor_add(cursor, hf_epmd_dist_high, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_dist_low, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_name_len, 2, FALSE);
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ptvcursor_add(cursor, hf_epmd_name, -1, FALSE);
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}
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case EPMD_ALIVE_OK:
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case EPMD_ALIVE2_OK: {
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ptvcursor_add(cursor, hf_epmd_result, 1, FALSE);
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ptvcursor_add(cursor, hf_epmd_creation, 2, FALSE);
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}
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default:
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break;
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}
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}
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static gboolean
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check_epmd(tvbuff_t *tvb)
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{
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guint8 type;
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/* simple heuristic:
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*
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* just check if the type is one of the EPMD
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* command types
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*
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* It's possible to start checking lengths but imho that
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* doesn't bring very much.
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*/
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if (tvb_length(tvb) < 3)
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return(FALSE);
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type = tvb_get_guint8(tvb, 0);
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switch (type) {
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case EPMD_ALIVE_OK:
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case EPMD_ALIVE2_OK:
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case EPMD_PORT_PLEASE2_OK:
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return(TRUE);
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default:
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break;
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}
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type = tvb_get_guint8(tvb, 2);
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switch (type) {
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case EPMD_ALIVE2:
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case EPMD_PORT_PLEASE:
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case EPMD_PORT_PLEASE2:
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case EPMD_NAMES:
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case EPMD_ALIVE:
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return( TRUE);
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default:
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break;
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}
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return(FALSE);
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}
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static int
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dissect_epmd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *epmd_tree;
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proto_item *ti;
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ptvcursor_t *cursor;
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if (!check_epmd(tvb))
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return(0);
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "EPMD");
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if (tree) {
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ti = proto_tree_add_item(tree, proto_epmd, tvb, 0, -1, FALSE);
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epmd_tree = proto_item_add_subtree(ti, ett_epmd);
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cursor = ptvcursor_new(epmd_tree, tvb, 0);
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if (pinfo->srcport==EPMD_PORT) {
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dissect_epmd_response(cursor);
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} else {
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dissect_epmd_request(cursor);
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}
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ptvcursor_free(cursor);
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}
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return(tvb_length(tvb));
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}
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void
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proto_register_epmd(void)
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{
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static hf_register_info hf[] = {
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{ &hf_epmd_len,
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{ "Length", "epmd.len",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Message Length", HFILL }},
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{ &hf_epmd_type,
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{ "Type", "epmd.type",
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FT_UINT8, BASE_DEC, VALS(message_types), 0x0,
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"Message Type", HFILL }},
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{ &hf_epmd_result,
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{ "Result", "epmd.result",
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FT_UINT8, BASE_DEC, NULL, 0x0,
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"Result", HFILL }},
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{ &hf_epmd_tcp_port,
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{ "TCP Port", "epmd.tcp_port",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"TCP Port", HFILL }},
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{ &hf_epmd_creation,
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{ "Creation", "epmd.creation",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Creation", HFILL }},
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{ &hf_epmd_dist_high,
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{ "Dist High", "epmd.dist_high",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Dist High", HFILL }},
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{ &hf_epmd_dist_low,
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{ "Dist Low", "epmd.dist_low",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Dist Low", HFILL }},
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{ &hf_epmd_name_len,
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{ "Name Length", "epmd.name_len",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Name Length", HFILL }},
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{ &hf_epmd_name,
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{ "Name", "epmd.name",
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FT_STRING, BASE_DEC, NULL, 0x0,
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"Name", HFILL }},
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{ &hf_epmd_elen,
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{ "Elen", "epmd.elen",
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FT_UINT16, BASE_DEC, NULL, 0x0,
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"Extra Length", HFILL }},
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{ &hf_epmd_edata,
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{ "Edata", "epmd.edata",
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FT_BYTES, BASE_DEC, NULL, 0x0,
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"Extra Data", HFILL }},
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{ &hf_epmd_names,
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{ "Names", "epmd.names",
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FT_BYTES, BASE_DEC, NULL, 0x0,
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"List of names", HFILL }}
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};
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static gint *ett[] = {
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&ett_epmd,
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};
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proto_epmd = proto_register_protocol("EPMD Protocol", "EPMD", "epmd");
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proto_register_field_array(proto_epmd, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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new_register_dissector("epmd", dissect_epmd, proto_epmd);
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}
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void
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proto_reg_handoff_epmd(void)
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{
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dissector_handle_t epmd_handle;
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epmd_handle = new_create_dissector_handle(dissect_epmd, proto_epmd);
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dissector_add("tcp.port", EPMD_PORT, epmd_handle);
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}
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