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