forked from osmocom/wireshark
210 lines
6.4 KiB
C
210 lines
6.4 KiB
C
/*
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* Routines for the disassembly of the proprietary Cisco IPSEC in
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* TCP encapsulation protocol
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*
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* $Id$
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*
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* Copyright 2007 Joerg Mayer (see AUTHORS file)
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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 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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/* TODO:
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* - Find out the meaning of the (unknown) trailer
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* - UDP checksum is wrong
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* - Currently doesn't handle AH (lack of sample trace)
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include <epan/packet.h>
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#include <epan/prefs.h>
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static int hf_tcpencap_unknown = -1;
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static int hf_tcpencap_zero = -1;
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static int hf_tcpencap_seq = -1;
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static int hf_tcpencap_ike_direction = -1;
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static int hf_tcpencap_esp_zero = -1;
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static int hf_tcpencap_magic = -1;
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static int hf_tcpencap_proto = -1;
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static int hf_tcpencap_magic2 = -1;
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static int proto_tcpencap = -1;
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static gint ett_tcpencap = -1;
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static gint ett_tcpencap_unknown = -1;
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static const value_string tcpencap_ikedir_vals[] = {
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{ 0x0000, "Server to client" },
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{ 0x4000, "Client to server" },
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{ 0, NULL }
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};
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static const value_string tcpencap_proto_vals[] = {
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{ 0x11, "ISAKMP" },
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{ 0x32, "ESP" },
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{ 0, NULL }
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};
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#define TCP_CISCO_IPSEC 10000
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static guint global_tcpencap_tcp_port = TCP_CISCO_IPSEC;
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static dissector_handle_t esp_handle;
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static dissector_handle_t udp_handle;
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#define TCP_ENCAP_P_ESP 1
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#define TCP_ENCAP_P_UDP 2
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/*
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* TCP Encapsulation of IPsec Packets
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* as supported by the cisco vpn3000 concentrator series
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*/
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static void
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dissect_tcpencap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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proto_tree *tcpencap_tree = NULL;
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proto_tree *tcpencap_unknown_tree = NULL;
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proto_item *tree_item = NULL;
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proto_item *unknown_item = NULL;
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tvbuff_t *next_tvb;
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guint32 reported_length = tvb_reported_length(tvb);
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guint32 offset;
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guint8 protocol;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "TCPENCAP");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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/* If the first 4 bytes are 0x01f401f4 (udp src and dst port = 500)
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we most likely have UDP (isakmp) traffic */
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if (tvb_get_ntohl(tvb, 0) == 0x01f401f4) { /* UDP means ISAKMP */
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protocol = TCP_ENCAP_P_UDP;
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} else { /* Hopefully ESP */
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protocol = TCP_ENCAP_P_ESP;
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}
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if (tree) {
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tree_item = proto_tree_add_item(tree, proto_tcpencap, tvb, 0, -1, FALSE);
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tcpencap_tree = proto_item_add_subtree(tree_item, ett_tcpencap);
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/* Dissect the trailer following the encapsulated IPSEC/ISAKMP packet */
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offset = reported_length - 16;
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unknown_item = proto_tree_add_item(tcpencap_tree, hf_tcpencap_unknown, tvb,
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offset, 16, FALSE);
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/* Try to guess the contents of the trailer */
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tcpencap_unknown_tree = proto_item_add_subtree(unknown_item, ett_tcpencap_unknown);
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_zero, tvb, offset + 0, 4, FALSE);
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_seq, tvb, offset + 4, 2, FALSE);
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if (protocol == TCP_ENCAP_P_UDP) {
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_ike_direction, tvb, offset + 6, 2, FALSE);
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} else {
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_esp_zero, tvb, offset + 6, 2, FALSE);
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}
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_magic, tvb, offset + 8, 5, FALSE);
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_proto, tvb, offset + 13, 1, FALSE);
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proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_magic2, tvb, offset + 14, 2, FALSE);
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}
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/* Create the tvbuffer for the next dissector */
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next_tvb = tvb_new_subset(tvb, 0, reported_length - 16 , -1);
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if (protocol == TCP_ENCAP_P_UDP) {
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call_dissector(udp_handle, next_tvb, pinfo, tree);
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} else { /* Hopefully ESP */
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call_dissector(esp_handle, next_tvb, pinfo, tree);
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}
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}
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void
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proto_reg_handoff_tcpencap(void)
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{
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dissector_handle_t tcpencap_handle;
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esp_handle = find_dissector("esp");
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udp_handle = find_dissector("udp");
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tcpencap_handle = create_dissector_handle(dissect_tcpencap, proto_tcpencap);
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dissector_add("tcp.port", global_tcpencap_tcp_port, tcpencap_handle);
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}
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void
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proto_register_tcpencap(void)
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{
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static hf_register_info hf[] = {
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{ &hf_tcpencap_unknown,
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{ "Unknown trailer", "tcpencap.unknown", FT_BYTES, BASE_NONE, NULL,
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0x0, "", HFILL }},
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{ &hf_tcpencap_zero,
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{ "All zero", "tcpencap.zero", FT_BYTES, BASE_NONE, NULL,
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0x0, "", HFILL }},
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{ &hf_tcpencap_seq,
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{ "Sequence number", "tcpencap.seq", FT_UINT16, BASE_HEX, NULL,
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0x0, "", HFILL }},
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{ &hf_tcpencap_esp_zero,
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{ "ESP zero", "tcpencap.espzero", FT_UINT16, BASE_HEX, NULL,
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0x0, "", HFILL }},
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{ &hf_tcpencap_ike_direction,
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{ "ISAKMP traffic direction", "tcpencap.ikedirection", FT_UINT16, BASE_HEX, VALS(tcpencap_ikedir_vals),
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0x0, "", HFILL }},
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{ &hf_tcpencap_magic,
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{ "Magic number", "tcpencap.magic", FT_BYTES, BASE_NONE, NULL,
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0x0, "", HFILL }},
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{ &hf_tcpencap_proto,
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{ "Protocol", "tcpencap.proto", FT_UINT8, BASE_HEX, VALS(tcpencap_proto_vals),
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0x0, "", HFILL }},
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{ &hf_tcpencap_magic2,
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{ "Magic 2", "tcpencap.magic2", FT_BYTES, BASE_NONE, NULL,
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0x0, "", HFILL }},
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};
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static gint *ett[] = {
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&ett_tcpencap,
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&ett_tcpencap_unknown,
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};
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module_t *tcpencap_module;
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proto_tcpencap = proto_register_protocol(
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"TCP Encapsulation of IPsec Packets", "TCPENCAP", "tcpencap");
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proto_register_field_array(proto_tcpencap, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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tcpencap_module = prefs_register_protocol(proto_tcpencap, proto_reg_handoff_tcpencap);
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prefs_register_uint_preference(tcpencap_module, "tcp.port", "IPSEC TCP Port",
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"Set the port for IPSEC/ISAKMP messages"
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"If other than the default of 10000)",
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10, &global_tcpencap_tcp_port);
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}
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