epan/dissectors/packet-pw-eth.c

   1 /* packet-pw-eth.c
   2  * Routines for ethernet PW dissection: it should be conform to RFC 4448.
   3  *
   4  * Copyright 2008 _FF_
   5  *
   6  * Francesco Fondelli <francesco dot fondelli, gmail dot com>
   7  *
   8  * $Id$
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald@wireshark.org>
  12  * Copyright 1998 Gerald Combs
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 # include "config.h"
  31 #endif
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <glib.h>
  37 #include <epan/packet.h>
  38 #include <epan/addr_resolv.h>
  39
  40 #include "packet-mpls.h"
  41
  42 static gint proto_pw_eth_cw = -1;
  43 static gint proto_pw_eth_nocw = -1;
  44 static gint proto_pw_eth_heuristic = -1;
  45
  46 static gint ett_pw_eth = -1;
  47
  48 static int hf_pw_eth = -1;
  49 static int hf_pw_eth_cw = -1;
  50 static int hf_pw_eth_cw_sequence_number = -1;
  51
  52 static dissector_handle_t eth_withoutfcs_handle;
  53
  54 static void
  55 dissect_pw_eth_cw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  56 {
  57         proto_tree *pw_eth_tree = NULL;
  58         proto_item *ti = NULL;
  59         tvbuff_t *next_tvb = NULL;
  60         guint16 sequence_number = 0;
  61
  62         if (tvb_reported_length_remaining(tvb, 0) < 4) {
  63                 if (tree)
  64                         proto_tree_add_text(tree, tvb, 0, -1,
  65                                             "Error processing Message");
  66                 return;
  67         }
  68
  69         if (dissect_try_cw_first_nibble(tvb, pinfo, tree))
  70                 return;
  71
  72         sequence_number = tvb_get_ntohs(tvb, 2);
  73         if (tree) {
  74                 ti = proto_tree_add_boolean(tree, hf_pw_eth_cw,
  75                                             tvb, 0, 0, TRUE);
  76                 PROTO_ITEM_SET_HIDDEN(ti);
  77                 ti = proto_tree_add_item(tree, proto_pw_eth_cw,
  78                                          tvb, 0, 4, FALSE);
  79                 pw_eth_tree = proto_item_add_subtree(ti, ett_pw_eth);
  80                 if (pw_eth_tree == NULL)
  81                         return;
  82                 proto_tree_add_uint_format(pw_eth_tree,
  83                                            hf_pw_eth_cw_sequence_number,
  84                                            tvb, 2, 2, sequence_number,
  85                                            "Sequence Number: %d",
  86                                            sequence_number);
  87         }
  88         next_tvb = tvb_new_subset(tvb, 4, -1, -1);
  89         call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
  90 }
  91
  92 static void
  93 dissect_pw_eth_nocw(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  94 {
  95         tvbuff_t *next_tvb = NULL;
  96         proto_item *ti = NULL;
  97
  98         if (tree) {
  99                 ti = proto_tree_add_boolean(tree, hf_pw_eth, tvb, 0, 0, TRUE);
 100                 PROTO_ITEM_SET_HIDDEN(ti);
 101         }
 102         next_tvb = tvb_new_subset(tvb, 0, -1, -1);
 103         call_dissector(eth_withoutfcs_handle, next_tvb, pinfo, tree);
 104 }
 105
 106 /*
 107  * FF: this function returns TRUE if the first 12 bytes in tvb looks like
 108  *     two valid ethernet addresses.  FALSE otherwise.
 109  */
 110 static gboolean
 111 looks_like_plain_eth(tvbuff_t *tvb _U_)
 112 {
 113         const gchar *manuf_name_da = NULL;
 114         const gchar *manuf_name_sa = NULL;
 115
 116         if (tvb_reported_length_remaining(tvb, 0) < 14) {
 117                 return FALSE;
 118         }
 119
 120         manuf_name_da = get_manuf_name_if_known(tvb_get_ptr(tvb, 0, 6));
 121         manuf_name_sa = get_manuf_name_if_known(tvb_get_ptr(tvb, 6, 6));
 122
 123         if (manuf_name_da && manuf_name_sa) {
 124                 return TRUE;
 125         }
 126
 127         return FALSE;
 128 }
 129
 130 static void
 131 dissect_pw_eth_heuristic(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 132 {
 133         if (looks_like_plain_eth(tvb)) {
 134                 call_dissector(find_dissector("pw_eth_nocw"), tvb, pinfo, tree);
 135         } else {
 136                 call_dissector(find_dissector("pw_eth_cw"), tvb, pinfo, tree);
 137         }
 138 }
 139
 140 void
 141 proto_register_pw_eth(void)
 142 {
 143         static hf_register_info hf[] = {
 144                 {
 145                         &hf_pw_eth,
 146                         {
 147                                 "PW (ethernet)",
 148                                 "pweth", FT_BOOLEAN,
 149                                 BASE_NONE, NULL, 0x0, NULL, HFILL
 150                         }
 151                 },
 152                 {
 153                         &hf_pw_eth_cw,
 154                         {
 155                                 "PW Control Word (ethernet)",
 156                                 "pweth.cw", FT_BOOLEAN,
 157                                 BASE_NONE, NULL, 0x0, NULL, HFILL
 158                         }
 159                 },
 160                 {
 161                         &hf_pw_eth_cw_sequence_number,
 162                         {
 163                                 "PW sequence number (ethernet)",
 164                                 "pweth.cw.sequence_number", FT_UINT16,
 165                                 BASE_DEC, NULL, 0x0, NULL, HFILL
 166                         }
 167                 }
 168         };
 169
 170         static gint *ett[] = {
 171                 &ett_pw_eth
 172         };
 173
 174         proto_pw_eth_cw =
 175           proto_register_protocol("PW Ethernet Control Word",
 176                                   "Ethernet PW (with CW)",
 177                                   "pwethcw");
 178         proto_pw_eth_nocw =
 179           proto_register_protocol("Ethernet PW (no CW)", /* not displayed */
 180                                   "Ethernet PW (no CW)",
 181                                   "pwethnocw");
 182         proto_pw_eth_heuristic =
 183           proto_register_protocol("Ethernet PW (CW heuristic)", /* not disp. */
 184                                   "Ethernet PW (CW heuristic)",
 185                                   "pwethheuristic");
 186         proto_register_field_array(proto_pw_eth_cw, hf, array_length(hf));
 187         proto_register_subtree_array(ett, array_length(ett));
 188         register_dissector("pw_eth_cw", dissect_pw_eth_cw, proto_pw_eth_cw);
 189         register_dissector("pw_eth_nocw", dissect_pw_eth_nocw,
 190                            proto_pw_eth_nocw);
 191         register_dissector("pw_eth_heuristic", dissect_pw_eth_heuristic,
 192                            proto_pw_eth_heuristic);
 193 }
 194
 195 void
 196 proto_reg_handoff_pw_eth(void)
 197 {
 198         dissector_handle_t pw_eth_handle_cw;
 199         dissector_handle_t pw_eth_handle_nocw;
 200         dissector_handle_t pw_eth_handle_heuristic;
 201
 202         eth_withoutfcs_handle = find_dissector("eth_withoutfcs");
 203
 204         pw_eth_handle_cw = find_dissector("pw_eth_cw");
 205         dissector_add("mpls.label", LABEL_INVALID, pw_eth_handle_cw);
 206
 207         pw_eth_handle_nocw = find_dissector("pw_eth_nocw");
 208         dissector_add("mpls.label", LABEL_INVALID, pw_eth_handle_nocw);
 209
 210         pw_eth_handle_heuristic = find_dissector("pw_eth_heuristic");
 211         dissector_add("mpls.label", LABEL_INVALID, pw_eth_handle_heuristic);
 212 }