packet-frame.c

   1 /* packet-frame.c
   2  *
   3  * Top-most dissector. Decides dissector based on Wiretap Encapsulation Type.
   4  *
   5  * $Id: packet-frame.c,v 1.22 2002/02/18 23:51:55 guy Exp $
   6  *
   7  * Ethereal - Network traffic analyzer
   8  * By Gerald Combs <gerald@ethereal.com>
   9  * Copyright 2000 Gerald Combs
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version 2
  14  * of the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 # include "config.h"
  28 #endif
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include <epan/timestamp.h>
  33 #include <epan/tvbuff.h>
  34 #include "packet-frame.h"
  35 #include "prefs.h"
  36
  37 static int proto_frame = -1;
  38 static int hf_frame_arrival_time = -1;
  39 static int hf_frame_time_delta = -1;
  40 static int hf_frame_time_relative = -1;
  41 static int hf_frame_number = -1;
  42 static int hf_frame_packet_len = -1;
  43 static int hf_frame_capture_len = -1;
  44 static int hf_frame_p2p_dir = -1;
  45 static int hf_frame_file_off = -1;
  46 static int proto_short = -1;
  47 int proto_malformed = -1;
  48 static int proto_unreassembled = -1;
  49
  50 static gint ett_frame = -1;
  51
  52 static dissector_handle_t data_handle;
  53
  54 /* Preferences */
  55 static gboolean show_file_off = FALSE;
  56
  57 static const value_string p2p_dirs[] = {
  58         { P2P_DIR_SENT, "Sent" },
  59         { P2P_DIR_RECV, "Received" },
  60         { 0, NULL }
  61 };
  62
  63 static dissector_table_t wtap_encap_dissector_table;
  64
  65 void
  66 dissect_frame(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  67 {
  68         proto_tree      *fh_tree;
  69         proto_item      *ti;
  70         nstime_t        ts;
  71         int             cap_len, pkt_len;
  72
  73         pinfo->current_proto = "Frame";
  74
  75         if (pinfo->fd->lnk_t == WTAP_ENCAP_LAPD ||
  76                         pinfo->fd->lnk_t == WTAP_ENCAP_CHDLC ||
  77                         pinfo->fd->lnk_t == WTAP_ENCAP_PPP_WITH_PHDR) {
  78
  79                 pinfo->p2p_dir = pinfo->pseudo_header->p2p.sent ? P2P_DIR_SENT : P2P_DIR_RECV;
  80         }
  81         else if (pinfo->fd->lnk_t == WTAP_ENCAP_LAPB ||
  82                         pinfo->fd->lnk_t == WTAP_ENCAP_FRELAY) {
  83
  84                 pinfo->p2p_dir = (pinfo->pseudo_header->x25.flags & 0x80) ? P2P_DIR_RECV : P2P_DIR_SENT;
  85         }
  86
  87         /* Put in frame header information. */
  88         if (tree) {
  89
  90           cap_len = tvb_length(tvb);
  91           pkt_len = tvb_reported_length(tvb);
  92
  93           ti = proto_tree_add_protocol_format(tree, proto_frame, tvb, 0, -1,
  94             "Frame %u (%u on wire, %u captured)", pinfo->fd->num, pkt_len, cap_len);
  95
  96           fh_tree = proto_item_add_subtree(ti, ett_frame);
  97
  98           ts.secs = pinfo->fd->abs_secs;
  99           ts.nsecs = pinfo->fd->abs_usecs*1000;
 100
 101           proto_tree_add_time(fh_tree, hf_frame_arrival_time, tvb,
 102                 0, 0, &ts);
 103
 104           ts.secs = pinfo->fd->del_secs;
 105           ts.nsecs = pinfo->fd->del_usecs*1000;
 106
 107           proto_tree_add_time(fh_tree, hf_frame_time_delta, tvb,
 108                 0, 0, &ts);
 109
 110           ts.secs = pinfo->fd->rel_secs;
 111           ts.nsecs = pinfo->fd->rel_usecs*1000;
 112
 113           proto_tree_add_time(fh_tree, hf_frame_time_relative, tvb,
 114                 0, 0, &ts);
 115
 116           proto_tree_add_uint(fh_tree, hf_frame_number, tvb,
 117                 0, 0, pinfo->fd->num);
 118
 119           proto_tree_add_uint_format(fh_tree, hf_frame_packet_len, tvb,
 120                 0, 0, pkt_len, "Packet Length: %d byte%s", pkt_len,
 121                 plurality(pkt_len, "", "s"));
 122
 123           proto_tree_add_uint_format(fh_tree, hf_frame_capture_len, tvb,
 124                 0, 0, cap_len, "Capture Length: %d byte%s", cap_len,
 125                 plurality(cap_len, "", "s"));
 126
 127           /* Check for existences of P2P pseudo header */
 128           if (pinfo->p2p_dir != P2P_DIR_UNKNOWN) {
 129                   proto_tree_add_uint(fh_tree, hf_frame_p2p_dir, tvb,
 130                                   0, 0, pinfo->p2p_dir);
 131           }
 132
 133           if (show_file_off) {
 134                   proto_tree_add_int_format(fh_tree, hf_frame_file_off, tvb,
 135                                   0, 0, pinfo->fd->file_off,
 136                                   "File Offset: %ld (0x%lx)",
 137                                   pinfo->fd->file_off, pinfo->fd->file_off);
 138           }
 139         }
 140
 141
 142         TRY {
 143                 if (!dissector_try_port(wtap_encap_dissector_table, pinfo->fd->lnk_t,
 144                                         tvb, pinfo, tree)) {
 145
 146                         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 147                                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "UNKNOWN");
 148                         if (check_col(pinfo->cinfo, COL_INFO))
 149                                 col_add_fstr(pinfo->cinfo, COL_INFO, "WTAP_ENCAP = %u",
 150                                     pinfo->fd->lnk_t);
 151                         call_dissector(data_handle,tvb, pinfo, tree);
 152                 }
 153         }
 154         CATCH(BoundsError) {
 155                 if (check_col(pinfo->cinfo, COL_INFO))
 156                         col_append_str(pinfo->cinfo, COL_INFO, "[Short Frame]");
 157                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
 158                                 "[Short Frame: %s]", pinfo->current_proto);
 159         }
 160         CATCH(ReportedBoundsError) {
 161                 show_reported_bounds_error(tvb, pinfo, tree);
 162         }
 163         ENDTRY;
 164 }
 165
 166 void
 167 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 168 {
 169         if (pinfo->fragmented) {
 170                 /*
 171                  * We were dissecting an unreassembled fragmented
 172                  * packet when the exception was thrown, so the
 173                  * problem isn't that the dissector expected
 174                  * something but it wasn't in the packet, the
 175                  * problem is that the dissector expected something
 176                  * but it wasn't in the fragment we dissected.
 177                  */
 178                 if (check_col(pinfo->cinfo, COL_INFO))
 179                         col_append_str(pinfo->cinfo, COL_INFO,
 180                             "[Unreassembled Packet]");
 181                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 182                     tvb, 0, 0, "[Unreassembled Packet: %s]",
 183                     pinfo->current_proto);
 184         } else {
 185                 if (check_col(pinfo->cinfo, COL_INFO))
 186                         col_append_str(pinfo->cinfo, COL_INFO,
 187                             "[Malformed Packet]");
 188                 proto_tree_add_protocol_format(tree, proto_malformed,
 189                     tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 190         }
 191 }
 192
 193 void
 194 proto_register_frame(void)
 195 {
 196         static hf_register_info hf[] = {
 197                 { &hf_frame_arrival_time,
 198                 { "Arrival Time",               "frame.time", FT_ABSOLUTE_TIME, BASE_NONE, NULL, 0x0,
 199                         "", HFILL }},
 200
 201                 { &hf_frame_time_delta,
 202                 { "Time delta from previous packet",    "frame.time_delta", FT_RELATIVE_TIME, BASE_NONE, NULL,
 203                         0x0,
 204                         "", HFILL }},
 205
 206                 { &hf_frame_time_relative,
 207                 { "Time relative to first packet",      "frame.time_relative", FT_RELATIVE_TIME, BASE_NONE, NULL,
 208                         0x0,
 209                         "", HFILL }},
 210
 211                 { &hf_frame_number,
 212                 { "Frame Number",               "frame.number", FT_UINT32, BASE_DEC, NULL, 0x0,
 213                         "", HFILL }},
 214
 215                 { &hf_frame_packet_len,
 216                 { "Total Frame Length",         "frame.pkt_len", FT_UINT32, BASE_DEC, NULL, 0x0,
 217                         "", HFILL }},
 218
 219                 { &hf_frame_capture_len,
 220                 { "Capture Frame Length",       "frame.cap_len", FT_UINT32, BASE_DEC, NULL, 0x0,
 221                         "", HFILL }},
 222
 223                 { &hf_frame_p2p_dir,
 224                 { "Point-to-Point Direction",   "frame.p2p_dir", FT_UINT8, BASE_DEC, VALS(p2p_dirs), 0x0,
 225                         "", HFILL }},
 226
 227                 { &hf_frame_file_off,
 228                 { "File Offset",        "frame.file_off", FT_INT32, BASE_DEC, NULL, 0x0,
 229                         "", HFILL }},
 230
 231         };
 232         static gint *ett[] = {
 233                 &ett_frame,
 234         };
 235         module_t *frame_module;
 236
 237         wtap_encap_dissector_table = register_dissector_table("wtap_encap",
 238             "Wiretap encapsulation type", FT_UINT32, BASE_DEC);
 239
 240         proto_frame = proto_register_protocol("Frame", "Frame", "frame");
 241         proto_register_field_array(proto_frame, hf, array_length(hf));
 242         proto_register_subtree_array(ett, array_length(ett));
 243         register_dissector("frame",dissect_frame,proto_frame);
 244
 245         /* You can't disable dissection of "Frame", as that would be
 246            tantamount to not doing any dissection whatsoever. */
 247         proto_set_cant_disable(proto_frame);
 248
 249         proto_short = proto_register_protocol("Short Frame", "Short frame", "short");
 250         proto_malformed = proto_register_protocol("Malformed Packet",
 251             "Malformed packet", "malformed");
 252         proto_unreassembled = proto_register_protocol(
 253             "Unreassembled Fragmented Packet",
 254             "Unreassembled fragmented packet", "unreassembled");
 255
 256         /* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
 257            Packet" aren't really protocols, they're error indications;
 258            disabling them makes no sense. */
 259         proto_set_cant_disable(proto_short);
 260         proto_set_cant_disable(proto_malformed);
 261         proto_set_cant_disable(proto_unreassembled);
 262
 263         /* Our preferences */
 264         frame_module = prefs_register_protocol(proto_frame, NULL);
 265         prefs_register_bool_preference(frame_module, "show_file_off",
 266             "Show File Offset", "Show File Offset", &show_file_off);
 267 }
 268
 269 void
 270 proto_reg_handoff_frame(void)
 271 {
 272         data_handle = find_dissector("data");
 273 }