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 #include <wsutil/ws_printf.h> /* ws_g_warning */
  34
  35 static int proto_short = -1;
  36 static int proto_malformed = -1;
  37 static int proto_unreassembled = -1;
  38
  39 static expert_field ei_malformed_dissector_bug = EI_INIT;
  40 static expert_field ei_malformed_reassembly = EI_INIT;
  41 static expert_field ei_malformed = EI_INIT;
  42
  43 void
  44 register_show_exception(void)
  45 {
  46         static ei_register_info ei[] = {
  47                 { &ei_malformed_dissector_bug, { "_ws.malformed.dissector_bug", PI_MALFORMED, PI_ERROR, "Dissector bug", EXPFILL }},
  48                 { &ei_malformed_reassembly, { "_ws.malformed.reassembly", PI_MALFORMED, PI_ERROR, "Reassembly error", EXPFILL }},
  49                 { &ei_malformed, { "_ws.malformed.expert", PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)", EXPFILL }},
  50         };
  51
  52         expert_module_t* expert_malformed;
  53
  54         proto_short = proto_register_protocol("Short Frame", "Short frame", "_ws.short");
  55         proto_malformed = proto_register_protocol("Malformed Packet",
  56             "Malformed packet", "_ws.malformed");
  57         proto_unreassembled = proto_register_protocol(
  58             "Unreassembled Fragmented Packet",
  59             "Unreassembled fragmented packet", "_ws.unreassembled");
  60
  61         expert_malformed = expert_register_protocol(proto_malformed);
  62         expert_register_field_array(expert_malformed, ei, array_length(ei));
  63
  64         /* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
  65            Packet" aren't really protocols, they're error indications;
  66            disabling them makes no sense. */
  67         proto_set_cant_toggle(proto_short);
  68         proto_set_cant_toggle(proto_malformed);
  69         proto_set_cant_toggle(proto_unreassembled);
  70 }
  71
  72 void
  73 show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
  74                unsigned long exception, const char *exception_message)
  75 {
  76         static const char dissector_error_nomsg[] =
  77                 "Dissector writer didn't bother saying what the error was";
  78         proto_item *item;
  79
  80         if (exception == ReportedBoundsError && pinfo->fragmented)
  81                 exception = FragmentBoundsError;
  82
  83         switch (exception) {
  84
  85         case ScsiBoundsError:
  86                 col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
  87                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
  88                                 "SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
  89                 /* Don't record ScsiBoundsError exceptions as expert events - they merely
  90                  * reflect a normal SCSI condition.
  91                  * (any case where it's caused by something else is a bug). */
  92                 break;
  93
  94         case BoundsError:
  95                 {
  96                 gboolean display_info = TRUE;
  97                 module_t * frame_module = prefs_find_module("frame");
  98                 if (frame_module != NULL)
  99                 {
 100                         pref_t *display_pref = prefs_find_preference(frame_module, "disable_packet_size_limited_in_summary");
 101                         if (display_pref)
 102                         {
 103                                 if (*display_pref->varp.boolp)
 104                                         display_info = FALSE;
 105                         }
 106                 }
 107
 108                 if (display_info)
 109                         col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
 110                 proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
 111                                 "[Packet size limited during capture: %s truncated]", pinfo->current_proto);
 112                 /* Don't record BoundsError exceptions as expert events - they merely
 113                  * reflect a capture done with a snapshot length too short to capture
 114                  * all of the packet
 115                  * (any case where it's caused by something else is a bug). */
 116         }
 117                 break;
 118
 119         case FragmentBoundsError:
 120                 col_append_fstr(pinfo->cinfo, COL_INFO, "[Unreassembled Packet%s]", pinfo->noreassembly_reason);
 121                 proto_tree_add_protocol_format(tree, proto_unreassembled,
 122                     tvb, 0, 0, "[Unreassembled Packet%s: %s]",
 123                     pinfo->noreassembly_reason, pinfo->current_proto);
 124                 /* Don't record FragmentBoundsError exceptions as expert events - they merely
 125                  * reflect dissection done with reassembly turned off
 126                  * (any case where it's caused by something else is a bug). */
 127                 break;
 128
 129         case ReportedBoundsError:
 130                 show_reported_bounds_error(tvb, pinfo, tree);
 131                 break;
 132
 133         case DissectorError:
 134                 col_append_fstr(pinfo->cinfo, COL_INFO,
 135                     "[Dissector bug, protocol %s: %s]",
 136                     pinfo->current_proto,
 137                     exception_message == NULL ?
 138                         dissector_error_nomsg : exception_message);
 139                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 140                     "[Dissector bug, protocol %s: %s]",
 141                     pinfo->current_proto,
 142                     exception_message == NULL ?
 143                         dissector_error_nomsg : exception_message);
 144                 ws_g_warning("Dissector bug, protocol %s, in packet %u: %s",
 145                     pinfo->current_proto, pinfo->num,
 146                     exception_message == NULL ?
 147                         dissector_error_nomsg : exception_message);
 148                 expert_add_info_format(pinfo, item, &ei_malformed_dissector_bug, "%s",
 149                     exception_message == NULL ?
 150                         dissector_error_nomsg : exception_message);
 151                 break;
 152
 153         case ReassemblyError:
 154                 col_append_fstr(pinfo->cinfo, COL_INFO,
 155                     "[Reassembly error, protocol %s: %s]",
 156                     pinfo->current_proto,
 157                     exception_message == NULL ?
 158                         dissector_error_nomsg : exception_message);
 159                 item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
 160                     "[Reassembly error, protocol %s: %s]",
 161                     pinfo->current_proto,
 162                     exception_message == NULL ?
 163                         dissector_error_nomsg : exception_message);
 164                 expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
 165                     exception_message == NULL ?
 166                         dissector_error_nomsg : exception_message);
 167                 break;
 168
 169         default:
 170                 /* XXX - we want to know, if an unknown exception passed until here, don't we? */
 171                 g_assert_not_reached();
 172         }
 173 }
 174
 175 void
 176 show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 177 {
 178         proto_item *item;
 179
 180         col_append_str(pinfo->cinfo, COL_INFO,
 181             "[Malformed Packet]");
 182         item = proto_tree_add_protocol_format(tree, proto_malformed,
 183             tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
 184         expert_add_info(pinfo, item, &ei_malformed);
 185 }
 186
 187 /*
 188  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 189  *
 190  * Local variables:
 191  * c-basic-offset: 8
 192  * tab-width: 8
 193  * indent-tabs-mode: t
 194  * End:
 195  *
 196  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 197  * :indentSize=8:tabSize=8:noTabs=false:
 198  */