epan/show_exception.c

   1 /* show_exception.c
   2  *
   3  * Routines to put exception information into the protocol tree
   4  *
   5  * $Id$
   6  *
   7  * Wireshark - Network traffic analyzer
   8  * By Gerald Combs <gerald@wireshark.org>
   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <glib.h>
  29 #include <epan/packet.h>
  30 #include <epan/exceptions.h>
  31 #include <epan/expert.h>
  32 #include <epan/show_exception.h>
  33
  34 static int proto_short = -1;
  35 static int proto_malformed = -1;
  36 static int proto_unreassembled = -1;
  37
  38 static expert_field ei_malformed_dissector_bug = EI_INIT;
  39 static expert_field ei_malformed_reassembly = EI_INIT;
  40 static expert_field ei_malformed = EI_INIT;
  41
  42 void
  43 register_show_exception(void)
  44 {
  45         static ei_register_info ei[] = {
  46                 { &ei_malformed_dissector_bug, { "_ws.malformed.dissector_bug", PI_MALFORMED, PI_ERROR, "Dissector bug", EXPFILL }},
  47                 { &ei_malformed_reassembly, { "_ws.malformed.reassembly", PI_MALFORMED, PI_ERROR, "Reassembly error", EXPFILL }},
  48                 { &ei_malformed, { "_ws.malformed.expert", PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)", EXPFILL }},
  49         };
  50
  51         expert_module_t* expert_malformed;
  52
  53         proto_short = proto_register_protocol("Short Frame", "Short frame", "_ws.short");
  54         proto_malformed = proto_register_protocol("Malformed Packet",
  55             "Malformed packet", "_ws.malformed");
  56         proto_unreassembled = proto_register_protocol(
  57             "Unreassembled Fragmented Packet",
  58             "Unreassembled fragmented packet", "_ws.unreassembled");
  59
  60         expert_malformed = expert_register_protocol(proto_malformed);
  61         expert_register_field_array(expert_malformed, ei, array_length(ei));
  62
  63         /* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
  64            Packet" aren't really protocols, they're error indications;
  65            disabling them makes no sense. */
  66         proto_set_cant_toggle(proto_short);
  67         proto_set_cant_toggle(proto_malformed);
  68         proto_set_cant_toggle(proto_unreassembled);
  69 }
  70
  71 void
  72 show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
  73                unsigned long exception, const char *exception_message)
  74 {
  75         static const char dissector_error_nomsg[] =
  76                 "Dissector writer didn't bother saying what the error was";
  77         proto_item *item;
  78
  79         if (exception == ReportedBoundsError && pinfo->fragmented)
  80                 exception = FragmentBoundsError;
  81
  82         switch (exception) {
  83
  84         case ScsiBoundsError:
  85                 col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
  86                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
  87                                 "SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
  88                 /* Don't record ScsiBoundsError exceptions as expert events - they merely
  89                  * reflect a normal SCSI condition.
  90                  * (any case where it's caused by something else is a bug). */
  91                 break;
  92
  93         case BoundsError:
  94                 col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
  95                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
  96                                 "[Packet size limited during capture: %s truncated]", pinfo->current_proto);
  97                 /* Don't record BoundsError exceptions as expert events - they merely
  98                  * reflect a capture done with a snapshot length too short to capture
  99                  * all of the packet
 100                  * (any case where it's caused by something else is a bug). */
 101                 break;
 102
 103         case FragmentBoundsError:
 104                 col_append_fstr(pinfo->cinfo, COL_INFO, "[Unreassembled Packet%s]", pinfo->noreassembly_reason);
 105                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 106                     tvb, 0, 0, "[Unreassembled Packet%s: %s]",
 107                     pinfo->noreassembly_reason, pinfo->current_proto);
 108                 /* Don't record FragmentBoundsError exceptions as expert events - they merely
 109                  * reflect dissection done with reassembly turned off
 110                  * (any case where it's caused by something else is a bug). */
 111                 break;
 112
 113         case ReportedBoundsError:
 114                 show_reported_bounds_error(tvb, pinfo, tree);
 115                 break;
 116
 117         case DissectorError:
 118                 col_append_fstr(pinfo->cinfo, COL_INFO,
 119                     "[Dissector bug, protocol %s: %s]",
 120                     pinfo->current_proto,
 121                     exception_message == NULL ?
 122                         dissector_error_nomsg : exception_message);
 123                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 124                     "[Dissector bug, protocol %s: %s]",
 125                     pinfo->current_proto,
 126                     exception_message == NULL ?
 127                         dissector_error_nomsg : exception_message);
 128                 g_warning("Dissector bug, protocol %s, in packet %u: %s",
 129                     pinfo->current_proto, pinfo->fd->num,
 130                     exception_message == NULL ?
 131                         dissector_error_nomsg : exception_message);
 132                 expert_add_info_format(pinfo, item, &ei_malformed_dissector_bug, "%s",
 133                     exception_message == NULL ?
 134                         dissector_error_nomsg : exception_message);
 135                 break;
 136
 137         case ReassemblyError:
 138                 col_append_fstr(pinfo->cinfo, COL_INFO,
 139                     "[Reassembly error, protocol %s: %s]",
 140                     pinfo->current_proto,
 141                     exception_message == NULL ?
 142                         dissector_error_nomsg : exception_message);
 143                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 144                     "[Reassembly error, protocol %s: %s]",
 145                     pinfo->current_proto,
 146                     exception_message == NULL ?
 147                         dissector_error_nomsg : exception_message);
 148                 expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
 149                     exception_message == NULL ?
 150                         dissector_error_nomsg : exception_message);
 151                 break;
 152
 153         default:
 154                 /* XXX - we want to know, if an unknown exception passed until here, don't we? */
 155                 g_assert_not_reached();
 156         }
 157 }
 158
 159 void
 160 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 161 {
 162         proto_item *item;
 163
 164         col_append_str(pinfo->cinfo, COL_INFO,
 165             "[Malformed Packet]");
 166         item = proto_tree_add_protocol_format(tree, proto_malformed,
 167             tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 168         expert_add_info(pinfo, item, &ei_malformed);
 169 }