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/prefs.h>
  31 #include <epan/prefs-int.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                 {
  95                 gboolean display_info = TRUE;
  96                 module_t * frame_module = prefs_find_module("frame");
  97                 if (frame_module != NULL)
  98                 {
  99                         pref_t *display_pref = prefs_find_preference(frame_module, "disable_packet_size_limited_in_summary");
 100                         if (display_pref)
 101                         {
 102                                 if (*display_pref->varp.boolp)
 103                                         display_info = FALSE;
 104                         }
 105                 }
 106
 107                 if (display_info)
 108                         col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
 109                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
 110                                 "[Packet size limited during capture: %s truncated]", pinfo->current_proto);
 111                 /* Don't record BoundsError exceptions as expert events - they merely
 112                  * reflect a capture done with a snapshot length too short to capture
 113                  * all of the packet
 114                  * (any case where it's caused by something else is a bug). */
 115         }
 116                 break;
 117
 118         case FragmentBoundsError:
 119                 col_append_fstr(pinfo->cinfo, COL_INFO, "[Unreassembled Packet%s]", pinfo->noreassembly_reason);
 120                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 121                     tvb, 0, 0, "[Unreassembled Packet%s: %s]",
 122                     pinfo->noreassembly_reason, pinfo->current_proto);
 123                 /* Don't record FragmentBoundsError exceptions as expert events - they merely
 124                  * reflect dissection done with reassembly turned off
 125                  * (any case where it's caused by something else is a bug). */
 126                 break;
 127
 128         case ReportedBoundsError:
 129                 show_reported_bounds_error(tvb, pinfo, tree);
 130                 break;
 131
 132         case DissectorError:
 133                 col_append_fstr(pinfo->cinfo, COL_INFO,
 134                     "[Dissector bug, protocol %s: %s]",
 135                     pinfo->current_proto,
 136                     exception_message == NULL ?
 137                         dissector_error_nomsg : exception_message);
 138                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 139                     "[Dissector bug, protocol %s: %s]",
 140                     pinfo->current_proto,
 141                     exception_message == NULL ?
 142                         dissector_error_nomsg : exception_message);
 143                 g_warning("Dissector bug, protocol %s, in packet %u: %s",
 144                     pinfo->current_proto, pinfo->fd->num,
 145                     exception_message == NULL ?
 146                         dissector_error_nomsg : exception_message);
 147                 expert_add_info_format(pinfo, item, &ei_malformed_dissector_bug, "%s",
 148                     exception_message == NULL ?
 149                         dissector_error_nomsg : exception_message);
 150                 break;
 151
 152         case ReassemblyError:
 153                 col_append_fstr(pinfo->cinfo, COL_INFO,
 154                     "[Reassembly error, protocol %s: %s]",
 155                     pinfo->current_proto,
 156                     exception_message == NULL ?
 157                         dissector_error_nomsg : exception_message);
 158                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 159                     "[Reassembly error, protocol %s: %s]",
 160                     pinfo->current_proto,
 161                     exception_message == NULL ?
 162                         dissector_error_nomsg : exception_message);
 163                 expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
 164                     exception_message == NULL ?
 165                         dissector_error_nomsg : exception_message);
 166                 break;
 167
 168         default:
 169                 /* XXX - we want to know, if an unknown exception passed until here, don't we? */
 170                 g_assert_not_reached();
 171         }
 172 }
 173
 174 void
 175 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 176 {
 177         proto_item *item;
 178
 179         col_append_str(pinfo->cinfo, COL_INFO,
 180             "[Malformed Packet]");
 181         item = proto_tree_add_protocol_format(tree, proto_malformed,
 182             tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 183         expert_add_info(pinfo, item, &ei_malformed);
 184 }
 185
 186 /*
 187  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 188  *
 189  * Local variables:
 190  * c-basic-offset: 8
 191  * tab-width: 8
 192  * indent-tabs-mode: t
 193  * End:
 194  *
 195  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 196  * :indentSize=8:tabSize=8:noTabs=false:
 197  */