/* show_exception.c
 *
 * Routines to put exception information into the protocol tree
 *
 * $Id: show_exception.c 48011 2013-03-02 16:39:56Z eapache $
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 2000 Gerald Combs
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <glib.h>
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/show_exception.h>

static int proto_short = -1;
int proto_malformed = -1;
static int proto_unreassembled = -1;

void
register_show_exception(void)
{
	proto_short = proto_register_protocol("Short Frame", "Short frame", "short");
	proto_malformed = proto_register_protocol("Malformed Packet",
	    "Malformed packet", "malformed");
	proto_unreassembled = proto_register_protocol(
	    "Unreassembled Fragmented Packet",
	    "Unreassembled fragmented packet", "unreassembled");

	/* "Short Frame", "Malformed Packet", and "Unreassembled Fragmented
	   Packet" aren't really protocols, they're error indications;
	   disabling them makes no sense. */
	proto_set_cant_toggle(proto_short);
	proto_set_cant_toggle(proto_malformed);
	proto_set_cant_toggle(proto_unreassembled);
}

void
show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
	       unsigned long exception, const char *exception_message)
{
	static const char dissector_error_nomsg[] =
		"Dissector writer didn't bother saying what the error was";
	proto_item *item;


	switch (exception) {

	case ScsiBoundsError:
		col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
		/*item =*/ proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
				"SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
		/* Don't record ScsiBoundsError exceptions as expert events - they merely
		 * reflect a normal SCSI condition.
		 * (any case where it's caused by something else is a bug). */
		/* expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR, "Packet size limited");*/
		break;

	case BoundsError:
		col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
		/*item =*/ proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
				"[Packet size limited during capture: %s truncated]", pinfo->current_proto);
		/* Don't record BoundsError exceptions as expert events - they merely
		 * reflect a capture done with a snapshot length too short to capture
		 * all of the packet
		 * (any case where it's caused by something else is a bug). */
		/* expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR, "Packet size limited");*/
		break;

	case ReportedBoundsError:
		show_reported_bounds_error(tvb, pinfo, tree);
		break;

	case DissectorError:
		col_append_fstr(pinfo->cinfo, COL_INFO,
		    "[Dissector bug, protocol %s: %s]",
		    pinfo->current_proto,
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
		    "[Dissector bug, protocol %s: %s]",
		    pinfo->current_proto,
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		g_warning("Dissector bug, protocol %s, in packet %u: %s",
		    pinfo->current_proto, pinfo->fd->num,
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
		    "%s",
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		break;

	case ReassemblyError:
		col_append_fstr(pinfo->cinfo, COL_INFO,
		    "[Reassembly error, protocol %s: %s]",
		    pinfo->current_proto,
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
		    "[Reassembly error, protocol %s: %s]",
		    pinfo->current_proto,
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
		    "%s",
		    exception_message == NULL ?
		        dissector_error_nomsg : exception_message);
		break;

	default:
		/* XXX - we want to know, if an unknown exception passed until here, don't we? */
		g_assert_not_reached();
	}
}

void
show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
	proto_item *item;

	if (pinfo->fragmented) {
		/*
		 * We were dissecting an unreassembled fragmented
		 * packet when the exception was thrown, so the
		 * problem isn't that the dissector expected
		 * something but it wasn't in the packet, the
		 * problem is that the dissector expected something
		 * but it wasn't in the fragment we dissected.
		 */
		col_append_fstr(pinfo->cinfo, COL_INFO,
		    "[Unreassembled Packet%s] ",
		    pinfo->noreassembly_reason);
		item = proto_tree_add_protocol_format(tree, proto_unreassembled,
		    tvb, 0, 0, "[Unreassembled Packet%s: %s]",
		    pinfo->noreassembly_reason, pinfo->current_proto);
		expert_add_info_format(pinfo, item, PI_REASSEMBLE, PI_WARN, "Unreassembled Packet (Exception occurred)");
	} else {
		col_append_str(pinfo->cinfo, COL_INFO,
		    "[Malformed Packet]");
		item = proto_tree_add_protocol_format(tree, proto_malformed,
		    tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
		expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)");
	}
}
