2 * Routines for the disassembly of the proprietary Cisco IPSEC in
3 * TCP encapsulation protocol
7 * Copyright 2007 Joerg Mayer (see AUTHORS file)
9 * Wireshark - Network traffic analyzer
10 * By Gerald Combs <gerald@wireshark.org>
11 * Copyright 1998 Gerald Combs
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version 2
16 * of the License, or (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 * - Find out the meaning of the (unknown) trailer
30 * - UDP checksum is wrong
31 * - Currently doesn't handle AH (lack of sample trace)
39 #include <epan/packet.h>
40 #include <epan/prefs.h>
41 #include "packet-ndmp.h"
43 static int hf_tcpencap_unknown = -1;
44 static int hf_tcpencap_zero = -1;
45 static int hf_tcpencap_seq = -1;
46 static int hf_tcpencap_ike_direction = -1;
47 static int hf_tcpencap_esp_zero = -1;
48 static int hf_tcpencap_magic = -1;
49 static int hf_tcpencap_proto = -1;
50 static int hf_tcpencap_magic2 = -1;
52 static int proto_tcpencap = -1;
53 static gint ett_tcpencap = -1;
54 static gint ett_tcpencap_unknown = -1;
56 static const value_string tcpencap_ikedir_vals[] = {
57 { 0x0000, "Server to client" },
58 { 0x4000, "Client to server" },
63 static const value_string tcpencap_proto_vals[] = {
70 #define TRAILERLENGTH 16
71 #define TCP_CISCO_IPSEC 10000
72 static guint global_tcpencap_tcp_port = TCP_CISCO_IPSEC;
74 static dissector_handle_t esp_handle;
75 static dissector_handle_t udp_handle;
77 #define TCP_ENCAP_P_ESP 1
78 #define TCP_ENCAP_P_UDP 2
81 /* Another case of several companies creating protocols and
82 choosing an easy-to-remember port. Playing tonight: Cisco vs NDMP.
85 packet_is_tcpencap(tvbuff_t *tvb, packet_info *pinfo, guint32 offset)
87 if ( /* Must be zero */
88 tvb_get_ntohl(tvb, offset + 0) != 0 ||
89 /* Lower 12 bits must be zero */
90 (tvb_get_ntohs(tvb, offset + 6) & 0xfff) != 0 ||
91 /* Protocol must be UDP or ESP */
92 (tvb_get_guint8(tvb, offset + 13) != 17 &&
93 tvb_get_guint8(tvb, offset + 13) != 50)
98 if(check_if_ndmp(tvb, pinfo)){
106 * TCP Encapsulation of IPsec Packets
107 * as supported by the cisco vpn3000 concentrator series
110 dissect_tcpencap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
112 proto_tree *tcpencap_tree = NULL;
113 proto_tree *tcpencap_unknown_tree = NULL;
115 proto_item *tree_item = NULL;
116 proto_item *unknown_item = NULL;
118 guint32 reported_length = tvb_reported_length(tvb);
122 /* verify that this looks like a tcpencap packet */
123 if (reported_length <= TRAILERLENGTH + 8 ||
124 !packet_is_tcpencap(tvb, pinfo, reported_length - TRAILERLENGTH) ) {
128 col_set_str(pinfo->cinfo, COL_PROTOCOL, "TCPENCAP");
129 col_clear(pinfo->cinfo, COL_INFO);
131 /* If the first 4 bytes are 0x01f401f4 (udp src and dst port = 500)
132 we most likely have UDP (isakmp) traffic */
134 if (tvb_get_ntohl(tvb, 0) == 0x01f401f4) { /* UDP means ISAKMP */
135 protocol = TCP_ENCAP_P_UDP;
136 } else { /* Hopefully ESP */
137 protocol = TCP_ENCAP_P_ESP;
141 tree_item = proto_tree_add_item(tree, proto_tcpencap, tvb, 0, -1, FALSE);
142 tcpencap_tree = proto_item_add_subtree(tree_item, ett_tcpencap);
144 /* Dissect the trailer following the encapsulated IPSEC/ISAKMP packet */
145 offset = reported_length - TRAILERLENGTH;
146 unknown_item = proto_tree_add_item(tcpencap_tree, hf_tcpencap_unknown, tvb,
147 offset, TRAILERLENGTH, FALSE);
148 /* Try to guess the contents of the trailer */
149 tcpencap_unknown_tree = proto_item_add_subtree(unknown_item, ett_tcpencap_unknown);
150 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_zero, tvb, offset + 0, 4, FALSE);
151 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_seq, tvb, offset + 4, 2, FALSE);
152 if (protocol == TCP_ENCAP_P_UDP) {
153 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_ike_direction, tvb, offset + 6, 2, FALSE);
155 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_esp_zero, tvb, offset + 6, 2, FALSE);
157 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_magic, tvb, offset + 8, 5, FALSE);
158 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_proto, tvb, offset + 13, 1, FALSE);
159 proto_tree_add_item(tcpencap_unknown_tree, hf_tcpencap_magic2, tvb, offset + 14, 2, FALSE);
162 /* Create the tvbuffer for the next dissector */
163 next_tvb = tvb_new_subset(tvb, 0, reported_length - TRAILERLENGTH , -1);
164 if (protocol == TCP_ENCAP_P_UDP) {
165 call_dissector(udp_handle, next_tvb, pinfo, tree);
166 } else { /* Hopefully ESP */
167 call_dissector(esp_handle, next_tvb, pinfo, tree);
170 return tvb_length(tvb);
174 proto_register_tcpencap(void)
176 static hf_register_info hf[] = {
178 { &hf_tcpencap_unknown,
179 { "Unknown trailer", "tcpencap.unknown", FT_BYTES, BASE_NONE, NULL,
183 { "All zero", "tcpencap.zero", FT_BYTES, BASE_NONE, NULL,
187 { "Sequence number", "tcpencap.seq", FT_UINT16, BASE_HEX, NULL,
190 { &hf_tcpencap_esp_zero,
191 { "ESP zero", "tcpencap.espzero", FT_UINT16, BASE_HEX, NULL,
194 { &hf_tcpencap_ike_direction,
195 { "ISAKMP traffic direction", "tcpencap.ikedirection", FT_UINT16, BASE_HEX, VALS(tcpencap_ikedir_vals),
198 { &hf_tcpencap_magic,
199 { "Magic number", "tcpencap.magic", FT_BYTES, BASE_NONE, NULL,
202 { &hf_tcpencap_proto,
203 { "Protocol", "tcpencap.proto", FT_UINT8, BASE_HEX, VALS(tcpencap_proto_vals),
206 { &hf_tcpencap_magic2,
207 { "Magic 2", "tcpencap.magic2", FT_BYTES, BASE_NONE, NULL,
212 static gint *ett[] = {
214 &ett_tcpencap_unknown,
217 module_t *tcpencap_module;
219 void proto_reg_handoff_tcpencap(void);
221 proto_tcpencap = proto_register_protocol(
222 "TCP Encapsulation of IPsec Packets", "TCPENCAP", "tcpencap");
223 proto_register_field_array(proto_tcpencap, hf, array_length(hf));
224 proto_register_subtree_array(ett, array_length(ett));
225 tcpencap_module = prefs_register_protocol(proto_tcpencap, proto_reg_handoff_tcpencap);
226 prefs_register_uint_preference(tcpencap_module, "tcp.port", "IPSEC TCP Port",
227 "Set the port for IPSEC/ISAKMP messages"
228 "If other than the default of 10000)",
229 10, &global_tcpencap_tcp_port);
233 proto_reg_handoff_tcpencap(void)
235 static dissector_handle_t tcpencap_handle;
236 static gboolean initialized = FALSE;
237 static guint tcpencap_tcp_port;
240 tcpencap_handle = new_create_dissector_handle(dissect_tcpencap, proto_tcpencap);
241 esp_handle = find_dissector("esp");
242 udp_handle = find_dissector("udp");
245 dissector_delete("tcp.port", tcpencap_tcp_port, tcpencap_handle);
248 tcpencap_tcp_port = global_tcpencap_tcp_port;
249 dissector_add("tcp.port", global_tcpencap_tcp_port, tcpencap_handle);