2 * Routines for ISO/OSI network and transport protocol packet disassembly
3 * Main entrance point and common functions
5 * $Id: packet-osi.c,v 1.47 2001/11/25 22:51:13 hagbard Exp $
6 * Laurent Deniel <deniel@worldnet.fr>
7 * Ralf Schneider <Ralf.Schneider@t-online.de>
9 * Ethereal - Network traffic analyzer
10 * By Gerald Combs <gerald@ethereal.com>
11 * Copyright 1998 Gerald Combs
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version 2
16 * of the License, or (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
33 #ifdef HAVE_SYS_TYPES_H
34 # include <sys/types.h>
46 #include "packet-osi.h"
47 #include "packet-isis.h"
48 #include "packet-esis.h"
52 calc_checksum( tvbuff_t *tvb, int offset, u_int len, u_int checksum) {
63 available_len = tvb_length_remaining( tvb, offset );
64 if ( available_len < len )
65 return( DATA_MISSING );
67 buffer = tvb_get_ptr( tvb, offset, len );
70 * The maximum values of c0 and c1 will occur if all bytes have the
71 * value 255; if so, then c0 will be len*255 and c1 will be
72 * (len*255 + (len-1)*255 + ... + 255), which is
73 * (len + (len - 1) + ... + 1)*255, or 255*(len*(len + 1))/2.
74 * This means it can overflow if "len" is 5804 or greater.
76 * (A+B) mod 255 = ((A mod 255) + (B mod 255) mod 255, so
77 * we can solve this by taking c0 and c1 mod 255 every
87 for (i = 0; i < seglen; i++) {
97 if (c0 != 0 || c1 != 0)
98 return( CKSUM_NOT_OK ); /* XXX - what should the checksum be? */
104 /* main entry point */
106 const value_string nlpid_vals[] = {
107 { NLPID_NULL, "NULL" },
108 { NLPID_T_70, "T.70" },
109 { NLPID_X_633, "X.633" },
110 { NLPID_Q_931, "Q.931" },
111 { NLPID_Q_2931, "Q.2931" },
112 { NLPID_Q_2119, "Q.2119" },
113 { NLPID_SNAP, "SNAP" },
114 { NLPID_ISO8473_CLNP, "CLNP" },
115 { NLPID_ISO9542_ESIS, "ESIS" },
116 { NLPID_ISO10589_ISIS, "ISIS" },
117 { NLPID_ISO10747_IDRP, "IDRP" },
118 { NLPID_ISO9542X25_ESIS, "ESIS (X.25)" },
119 { NLPID_ISO10030, "ISO 10030" },
120 { NLPID_ISO11577, "ISO 11577" },
121 { NLPID_COMPRESSED, "Data compression protocol" },
123 { NLPID_IP6, "IPv6" },
124 { NLPID_PPP, "PPP" },
128 dissector_table_t osinl_subdissector_table;
129 static dissector_handle_t data_handle;
131 static void dissect_osi(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
135 pinfo->current_proto = "OSI";
137 nlpid = tvb_get_guint8(tvb, 0);
139 /* do lookup with the subdissector table */
140 if (dissector_try_port(osinl_subdissector_table, nlpid, tvb, pinfo, tree))
145 /* ESIS (X.25) is not currently decoded */
147 case NLPID_ISO9542X25_ESIS:
148 if (check_col(pinfo->fd, COL_PROTOCOL)) {
149 col_set_str(pinfo->fd, COL_PROTOCOL, "ESIS (X.25)");
151 call_dissector(data_handle,tvb, pinfo, tree);
153 case NLPID_ISO10747_IDRP:
154 if (check_col(pinfo->fd, COL_PROTOCOL)) {
155 col_set_str(pinfo->fd, COL_PROTOCOL, "IDRP");
157 call_dissector(data_handle,tvb, pinfo, tree);
160 if (check_col(pinfo->fd, COL_PROTOCOL)) {
161 col_set_str(pinfo->fd, COL_PROTOCOL, "ISO");
163 if (check_col(pinfo->fd, COL_INFO)) {
164 col_add_fstr(pinfo->fd, COL_INFO, "Unknown ISO protocol (%02x)", nlpid);
166 call_dissector(data_handle,tvb, pinfo, tree);
172 proto_register_osi(void)
174 /* There's no "OSI" protocol *per se*, but we do register a
175 dissector table so various protocols running at the
176 network layer can register themselves. */
177 osinl_subdissector_table = register_dissector_table("osinl");
181 proto_reg_handoff_osi(void)
183 dissector_add("llc.dsap", SAP_OSINL, dissect_osi, -1);
184 dissector_add("ppp.protocol", PPP_OSI, dissect_osi, -1);
185 dissector_add("null.type", BSD_AF_ISO, dissect_osi, -1);
186 data_handle = find_dissector("data");