epan/show_exception.c

   1 /* show_exception.c
   2  *
   3  * Routines to put exception information into the protocol tree
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 2000 Gerald Combs
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * as published by the Free Software Foundation; either version 2
  12  * of the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #include "config.h"
  25
  26 #include <glib.h>
  27 #include <epan/packet.h>
  28 #include <epan/exceptions.h>
  29 #include <epan/expert.h>
  30 #include <epan/show_exception.h>
  31
  32 static int proto_short = -1;
  33 static int proto_malformed = -1;
  34 static int proto_unreassembled = -1;
  35
  36 static expert_field ei_malformed_dissector_bug = EI_INIT;
  37 static expert_field ei_malformed_reassembly = EI_INIT;
  38 static expert_field ei_malformed = EI_INIT;
  39
  40 void
  41 register_show_exception(void)
  42 {
  43         static ei_register_info ei[] = {
  44                 { &ei_malformed_dissector_bug, { "_ws.malformed.dissector_bug", PI_MALFORMED, PI_ERROR, "Dissector bug", EXPFILL }},
  45                 { &ei_malformed_reassembly, { "_ws.malformed.reassembly", PI_MALFORMED, PI_ERROR, "Reassembly error", EXPFILL }},
  46                 { &ei_malformed, { "_ws.malformed.expert", PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)", EXPFILL }},
  47         };
  48
  49         expert_module_t* expert_malformed;
  50
  51         proto_short = proto_register_protocol("Short Frame", "Short frame", "_ws.short");
  52         proto_malformed = proto_register_protocol("Malformed Packet",
  53             "Malformed packet", "_ws.malformed");
  54         proto_unreassembled = proto_register_protocol(
  55             "Unreassembled Fragmented Packet",
  56             "Unreassembled fragmented packet", "_ws.unreassembled");
  57
  58         expert_malformed = expert_register_protocol(proto_malformed);
  59         expert_register_field_array(expert_malformed, ei, array_length(ei));
  60
  61         /* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
  62            Packet" aren't really protocols, they're error indications;
  63            disabling them makes no sense. */
  64         proto_set_cant_toggle(proto_short);
  65         proto_set_cant_toggle(proto_malformed);
  66         proto_set_cant_toggle(proto_unreassembled);
  67 }
  68
  69 void
  70 show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
  71                unsigned long exception, const char *exception_message)
  72 {
  73         static const char dissector_error_nomsg[] =
  74                 "Dissector writer didn't bother saying what the error was";
  75         proto_item *item;
  76
  77         if (exception == ReportedBoundsError && pinfo->fragmented)
  78                 exception = FragmentBoundsError;
  79
  80         switch (exception) {
  81
  82         case ScsiBoundsError:
  83                 col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
  84                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
  85                                 "SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
  86                 /* Don't record ScsiBoundsError exceptions as expert events - they merely
  87                  * reflect a normal SCSI condition.
  88                  * (any case where it's caused by something else is a bug). */
  89                 break;
  90
  91         case BoundsError:
  92                 col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
  93                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
  94                                 "[Packet size limited during capture: %s truncated]", pinfo->current_proto);
  95                 /* Don't record BoundsError exceptions as expert events - they merely
  96                  * reflect a capture done with a snapshot length too short to capture
  97                  * all of the packet
  98                  * (any case where it's caused by something else is a bug). */
  99                 break;
 100
 101         case FragmentBoundsError:
 102                 col_append_fstr(pinfo->cinfo, COL_INFO, "[Unreassembled Packet%s]", pinfo->noreassembly_reason);
 103                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 104                     tvb, 0, 0, "[Unreassembled Packet%s: %s]",
 105                     pinfo->noreassembly_reason, pinfo->current_proto);
 106                 /* Don't record FragmentBoundsError exceptions as expert events - they merely
 107                  * reflect dissection done with reassembly turned off
 108                  * (any case where it's caused by something else is a bug). */
 109                 break;
 110
 111         case ReportedBoundsError:
 112                 show_reported_bounds_error(tvb, pinfo, tree);
 113                 break;
 114
 115         case DissectorError:
 116                 col_append_fstr(pinfo->cinfo, COL_INFO,
 117                     "[Dissector bug, protocol %s: %s]",
 118                     pinfo->current_proto,
 119                     exception_message == NULL ?
 120                         dissector_error_nomsg : exception_message);
 121                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 122                     "[Dissector bug, protocol %s: %s]",
 123                     pinfo->current_proto,
 124                     exception_message == NULL ?
 125                         dissector_error_nomsg : exception_message);
 126                 g_warning("Dissector bug, protocol %s, in packet %u: %s",
 127                     pinfo->current_proto, pinfo->fd->num,
 128                     exception_message == NULL ?
 129                         dissector_error_nomsg : exception_message);
 130                 expert_add_info_format(pinfo, item, &ei_malformed_dissector_bug, "%s",
 131                     exception_message == NULL ?
 132                         dissector_error_nomsg : exception_message);
 133                 break;
 134
 135         case ReassemblyError:
 136                 col_append_fstr(pinfo->cinfo, COL_INFO,
 137                     "[Reassembly error, protocol %s: %s]",
 138                     pinfo->current_proto,
 139                     exception_message == NULL ?
 140                         dissector_error_nomsg : exception_message);
 141                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 142                     "[Reassembly error, protocol %s: %s]",
 143                     pinfo->current_proto,
 144                     exception_message == NULL ?
 145                         dissector_error_nomsg : exception_message);
 146                 expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
 147                     exception_message == NULL ?
 148                         dissector_error_nomsg : exception_message);
 149                 break;
 150
 151         default:
 152                 /* XXX - we want to know, if an unknown exception passed until here, don't we? */
 153                 g_assert_not_reached();
 154         }
 155 }
 156
 157 void
 158 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 159 {
 160         proto_item *item;
 161
 162         col_append_str(pinfo->cinfo, COL_INFO,
 163             "[Malformed Packet]");
 164         item = proto_tree_add_protocol_format(tree, proto_malformed,
 165             tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 166         expert_add_info(pinfo, item, &ei_malformed);
 167 }