4e184104af
FragmentBoundsErrors aren't malformed, but add an expert warning at the PI_NOTE level to hint to users that they may want to turn on reassembly preferences.
202 lines
7.1 KiB
C
202 lines
7.1 KiB
C
/* show_exception.c
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*
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* Routines to put exception information into the protocol tree
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 2000 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#define WS_LOG_DOMAIN LOG_DOMAIN_EPAN
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/exceptions.h>
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#include <epan/expert.h>
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#include <epan/prefs.h>
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#include <epan/prefs-int.h>
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#include <epan/show_exception.h>
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#include <wsutil/ws_assert.h>
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#include <wsutil/wslog.h>
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static int proto_short = -1;
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static int proto_malformed = -1;
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static int proto_unreassembled = -1;
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static expert_field ei_malformed_dissector_bug = EI_INIT;
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static expert_field ei_malformed_reassembly = EI_INIT;
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static expert_field ei_malformed = EI_INIT;
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static expert_field ei_unreassembled = EI_INIT;
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void
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register_show_exception(void)
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{
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static ei_register_info ei[] = {
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{ &ei_malformed_dissector_bug, { "_ws.malformed.dissector_bug", PI_MALFORMED, PI_ERROR, "Dissector bug", EXPFILL }},
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{ &ei_malformed_reassembly, { "_ws.malformed.reassembly", PI_MALFORMED, PI_ERROR, "Reassembly error", EXPFILL }},
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{ &ei_malformed, { "_ws.malformed.expert", PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)", EXPFILL }},
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{ &ei_unreassembled, { "_ws.unreassembled.expert", PI_REASSEMBLE, PI_NOTE, "Unreassembled fragment (change preferences to enable reassembly)", EXPFILL }},
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};
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expert_module_t* expert_malformed;
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proto_short = proto_register_protocol("Short Frame", "Short frame", "_ws.short");
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proto_malformed = proto_register_protocol("Malformed Packet",
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"Malformed packet", "_ws.malformed");
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proto_unreassembled = proto_register_protocol(
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"Unreassembled Fragmented Packet",
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"Unreassembled fragmented packet", "_ws.unreassembled");
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expert_malformed = expert_register_protocol(proto_malformed);
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expert_register_field_array(expert_malformed, ei, array_length(ei));
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/* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
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Packet" aren't really protocols, they're error indications;
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disabling them makes no sense. */
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proto_set_cant_toggle(proto_short);
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proto_set_cant_toggle(proto_malformed);
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proto_set_cant_toggle(proto_unreassembled);
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}
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void
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show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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unsigned long exception, const char *exception_message)
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{
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static const char dissector_error_nomsg[] =
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"Dissector writer didn't bother saying what the error was";
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proto_item *item;
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if ((exception == ReportedBoundsError || exception == ContainedBoundsError) && pinfo->fragmented)
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exception = FragmentBoundsError;
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switch (exception) {
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case ScsiBoundsError:
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col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
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proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
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"SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
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/* Don't record ScsiBoundsError exceptions as expert events - they merely
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* reflect a normal SCSI condition.
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* (any case where it's caused by something else is a bug). */
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break;
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case BoundsError:
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{
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gboolean display_info = TRUE;
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module_t * frame_module = prefs_find_module("frame");
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if (frame_module != NULL)
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{
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pref_t *display_pref = prefs_find_preference(frame_module, "disable_packet_size_limited_in_summary");
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if (display_pref)
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{
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if (prefs_get_bool_value(display_pref, pref_current))
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display_info = FALSE;
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}
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}
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if (display_info)
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col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
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proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
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"[Packet size limited during capture: %s truncated]", pinfo->current_proto);
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/* Don't record BoundsError exceptions as expert events - they merely
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* reflect a capture done with a snapshot length too short to capture
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* all of the packet
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* (any case where it's caused by something else is a bug). */
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}
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break;
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case FragmentBoundsError:
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col_append_fstr(pinfo->cinfo, COL_INFO, "[BoundErrorUnreassembled Packet%s]", pinfo->noreassembly_reason);
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item = proto_tree_add_protocol_format(tree, proto_unreassembled,
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tvb, 0, 0, "[BoundError Unreassembled Packet%s: %s]",
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pinfo->noreassembly_reason, pinfo->current_proto);
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/* FragmentBoundsError merely reflect dissection done with
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* reassembly turned off, so add a note to that effect
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* (any case where it's caused by something else is a bug). */
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expert_add_info(pinfo, item, &ei_unreassembled);
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break;
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case ContainedBoundsError:
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col_append_fstr(pinfo->cinfo, COL_INFO, "[Malformed Packet: length of contained item exceeds length of containing item]");
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item = proto_tree_add_protocol_format(tree, proto_malformed,
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tvb, 0, 0, "[Malformed Packet: %s: length of contained item exceeds length of containing item]",
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pinfo->current_proto);
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expert_add_info(pinfo, item, &ei_malformed);
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break;
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case ReportedBoundsError:
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show_reported_bounds_error(tvb, pinfo, tree);
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break;
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case DissectorError:
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col_append_fstr(pinfo->cinfo, COL_INFO,
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"[Dissector bug, protocol %s: %s]",
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pinfo->current_proto,
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
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"[Dissector bug, protocol %s: %s]",
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pinfo->current_proto,
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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ws_log(WS_LOG_DOMAIN, LOG_LEVEL_WARNING,
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"Dissector bug, protocol %s, in packet %u: %s",
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pinfo->current_proto, pinfo->num,
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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expert_add_info_format(pinfo, item, &ei_malformed_dissector_bug, "%s",
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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break;
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case ReassemblyError:
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col_append_fstr(pinfo->cinfo, COL_INFO,
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"[Reassembly error, protocol %s: %s]",
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pinfo->current_proto,
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
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"[Reassembly error, protocol %s: %s]",
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pinfo->current_proto,
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
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exception_message == NULL ?
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dissector_error_nomsg : exception_message);
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break;
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default:
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/* XXX - we want to know, if an unknown exception passed until here, don't we? */
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ws_assert_not_reached();
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}
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}
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void
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show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_item *item;
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col_append_str(pinfo->cinfo, COL_INFO,
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"[Malformed Packet]");
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item = proto_tree_add_protocol_format(tree, proto_malformed,
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tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
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expert_add_info(pinfo, item, &ei_malformed);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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