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 1.24 2002/04/13 00:02:55 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 static 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->pseudo_header != NULL) {
  76                 switch (pinfo->fd->lnk_t) {
  77
  78                 case WTAP_ENCAP_LAPD:
  79                 case WTAP_ENCAP_CHDLC:
  80                 case WTAP_ENCAP_PPP_WITH_PHDR:
  81                         pinfo->p2p_dir = pinfo->pseudo_header->p2p.sent ?
  82                             P2P_DIR_SENT : P2P_DIR_RECV;
  83                         break;
  84
  85                 case WTAP_ENCAP_LAPB:
  86                 case WTAP_ENCAP_FRELAY:
  87                         pinfo->p2p_dir =
  88                             (pinfo->pseudo_header->x25.flags & FROM_DCE) ?
  89                             P2P_DIR_RECV : P2P_DIR_SENT;
  90                         break;
  91                 }
  92         }
  93
  94         /* Put in frame header information. */
  95         if (tree) {
  96
  97           cap_len = tvb_length(tvb);
  98           pkt_len = tvb_reported_length(tvb);
  99
 100           ti = proto_tree_add_protocol_format(tree, proto_frame, tvb, 0, -1,
 101             "Frame %u (%u on wire, %u captured)", pinfo->fd->num, pkt_len, cap_len);
 102
 103           fh_tree = proto_item_add_subtree(ti, ett_frame);
 104
 105           ts.secs = pinfo->fd->abs_secs;
 106           ts.nsecs = pinfo->fd->abs_usecs*1000;
 107
 108           proto_tree_add_time(fh_tree, hf_frame_arrival_time, tvb,
 109                 0, 0, &ts);
 110
 111           ts.secs = pinfo->fd->del_secs;
 112           ts.nsecs = pinfo->fd->del_usecs*1000;
 113
 114           proto_tree_add_time(fh_tree, hf_frame_time_delta, tvb,
 115                 0, 0, &ts);
 116
 117           ts.secs = pinfo->fd->rel_secs;
 118           ts.nsecs = pinfo->fd->rel_usecs*1000;
 119
 120           proto_tree_add_time(fh_tree, hf_frame_time_relative, tvb,
 121                 0, 0, &ts);
 122
 123           proto_tree_add_uint(fh_tree, hf_frame_number, tvb,
 124                 0, 0, pinfo->fd->num);
 125
 126           proto_tree_add_uint_format(fh_tree, hf_frame_packet_len, tvb,
 127                 0, 0, pkt_len, "Packet Length: %d byte%s", pkt_len,
 128                 plurality(pkt_len, "", "s"));
 129
 130           proto_tree_add_uint_format(fh_tree, hf_frame_capture_len, tvb,
 131                 0, 0, cap_len, "Capture Length: %d byte%s", cap_len,
 132                 plurality(cap_len, "", "s"));
 133
 134           /* Check for existences of P2P pseudo header */
 135           if (pinfo->p2p_dir != P2P_DIR_UNKNOWN) {
 136                   proto_tree_add_uint(fh_tree, hf_frame_p2p_dir, tvb,
 137                                   0, 0, pinfo->p2p_dir);
 138           }
 139
 140           if (show_file_off) {
 141                   proto_tree_add_int_format(fh_tree, hf_frame_file_off, tvb,
 142                                   0, 0, pinfo->fd->file_off,
 143                                   "File Offset: %ld (0x%lx)",
 144                                   pinfo->fd->file_off, pinfo->fd->file_off);
 145           }
 146         }
 147
 148
 149         TRY {
 150                 if (!dissector_try_port(wtap_encap_dissector_table, pinfo->fd->lnk_t,
 151                                         tvb, pinfo, tree)) {
 152
 153                         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 154                                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "UNKNOWN");
 155                         if (check_col(pinfo->cinfo, COL_INFO))
 156                                 col_add_fstr(pinfo->cinfo, COL_INFO, "WTAP_ENCAP = %u",
 157                                     pinfo->fd->lnk_t);
 158                         call_dissector(data_handle,tvb, pinfo, tree);
 159                 }
 160         }
 161         CATCH(BoundsError) {
 162                 if (check_col(pinfo->cinfo, COL_INFO))
 163                         col_append_str(pinfo->cinfo, COL_INFO, "[Short Frame]");
 164                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
 165                                 "[Short Frame: %s]", pinfo->current_proto);
 166         }
 167         CATCH(ReportedBoundsError) {
 168                 show_reported_bounds_error(tvb, pinfo, tree);
 169         }
 170         ENDTRY;
 171 }
 172
 173 void
 174 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 175 {
 176         if (pinfo->fragmented) {
 177                 /*
 178                  * We were dissecting an unreassembled fragmented
 179                  * packet when the exception was thrown, so the
 180                  * problem isn't that the dissector expected
 181                  * something but it wasn't in the packet, the
 182                  * problem is that the dissector expected something
 183                  * but it wasn't in the fragment we dissected.
 184                  */
 185                 if (check_col(pinfo->cinfo, COL_INFO))
 186                         col_append_str(pinfo->cinfo, COL_INFO,
 187                             "[Unreassembled Packet]");
 188                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 189                     tvb, 0, 0, "[Unreassembled Packet: %s]",
 190                     pinfo->current_proto);
 191         } else {
 192                 if (check_col(pinfo->cinfo, COL_INFO))
 193                         col_append_str(pinfo->cinfo, COL_INFO,
 194                             "[Malformed Packet]");
 195                 proto_tree_add_protocol_format(tree, proto_malformed,
 196                     tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 197         }
 198 }
 199
 200 void
 201 proto_register_frame(void)
 202 {
 203         static hf_register_info hf[] = {
 204                 { &hf_frame_arrival_time,
 205                 { "Arrival Time",               "frame.time", FT_ABSOLUTE_TIME, BASE_NONE, NULL, 0x0,
 206                         "", HFILL }},
 207
 208                 { &hf_frame_time_delta,
 209                 { "Time delta from previous packet",    "frame.time_delta", FT_RELATIVE_TIME, BASE_NONE, NULL,
 210                         0x0,
 211                         "", HFILL }},
 212
 213                 { &hf_frame_time_relative,
 214                 { "Time relative to first packet",      "frame.time_relative", FT_RELATIVE_TIME, BASE_NONE, NULL,
 215                         0x0,
 216                         "", HFILL }},
 217
 218                 { &hf_frame_number,
 219                 { "Frame Number",               "frame.number", FT_UINT32, BASE_DEC, NULL, 0x0,
 220                         "", HFILL }},
 221
 222                 { &hf_frame_packet_len,
 223                 { "Total Frame Length",         "frame.pkt_len", FT_UINT32, BASE_DEC, NULL, 0x0,
 224                         "", HFILL }},
 225
 226                 { &hf_frame_capture_len,
 227                 { "Capture Frame Length",       "frame.cap_len", FT_UINT32, BASE_DEC, NULL, 0x0,
 228                         "", HFILL }},
 229
 230                 { &hf_frame_p2p_dir,
 231                 { "Point-to-Point Direction",   "frame.p2p_dir", FT_UINT8, BASE_DEC, VALS(p2p_dirs), 0x0,
 232                         "", HFILL }},
 233
 234                 { &hf_frame_file_off,
 235                 { "File Offset",        "frame.file_off", FT_INT32, BASE_DEC, NULL, 0x0,
 236                         "", HFILL }},
 237
 238         };
 239         static gint *ett[] = {
 240                 &ett_frame,
 241         };
 242         module_t *frame_module;
 243
 244         wtap_encap_dissector_table = register_dissector_table("wtap_encap",
 245             "Wiretap encapsulation type", FT_UINT32, BASE_DEC);
 246
 247         proto_frame = proto_register_protocol("Frame", "Frame", "frame");
 248         proto_register_field_array(proto_frame, hf, array_length(hf));
 249         proto_register_subtree_array(ett, array_length(ett));
 250         register_dissector("frame",dissect_frame,proto_frame);
 251
 252         /* You can't disable dissection of "Frame", as that would be
 253            tantamount to not doing any dissection whatsoever. */
 254         proto_set_cant_disable(proto_frame);
 255
 256         proto_short = proto_register_protocol("Short Frame", "Short frame", "short");
 257         proto_malformed = proto_register_protocol("Malformed Packet",
 258             "Malformed packet", "malformed");
 259         proto_unreassembled = proto_register_protocol(
 260             "Unreassembled Fragmented Packet",
 261             "Unreassembled fragmented packet", "unreassembled");
 262
 263         /* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
 264            Packet" aren't really protocols, they're error indications;
 265            disabling them makes no sense. */
 266         proto_set_cant_disable(proto_short);
 267         proto_set_cant_disable(proto_malformed);
 268         proto_set_cant_disable(proto_unreassembled);
 269
 270         /* Our preferences */
 271         frame_module = prefs_register_protocol(proto_frame, NULL);
 272         prefs_register_bool_preference(frame_module, "show_file_off",
 273             "Show File Offset", "Show File Offset", &show_file_off);
 274 }
 275
 276 void
 277 proto_reg_handoff_frame(void)
 278 {
 279         data_handle = find_dissector("data");
 280 }