2 * Routines for Jmirror protocol packet disassembly
3 * By Wayne Brassem <wbrassem@juniper.net>
4 * Copyright 2009 Wayne Brassem
8 * Wireshark - Network traffic analyzer
9 * By Gerald Combs <gerald@wireshark.org>
10 * Copyright 1998 Gerald Combs
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
31 #include <epan/packet.h>
32 #include <epan/prefs.h>
34 #define MIRROR_HDR_SZ 8
35 #define MIRROR_ID_SZ 4
36 #define SESSION_ID_SZ 4
37 #define DEF_JMIRROR_UDP_PORT 30030 /* a product of primes (1*2*3*5*7*11*13) :-) */
40 * See www.juniper.net JUNOSe Packet Mirroring documentation
43 /* Jmirror protocol variables */
44 static int proto_jmirror = -1;
45 static int hf_jmirror_mid = -1;
46 static int hf_jmirror_sid = -1;
47 static gint ett_jmirror = -1;
49 /* Handles which point to the packet dissectors */
50 static dissector_handle_t ipv4_handle;
51 static dissector_handle_t ipv6_handle;
52 static dissector_handle_t hdlc_handle;
54 static guint global_jmirror_udp_port = DEF_JMIRROR_UDP_PORT;
56 /* Forward declaration */
57 void proto_reg_handoff_jmirror(void);
59 /* Routine to return the dissector handle based on heuristic packet inspection */
60 static dissector_handle_t
61 get_heuristic_handle(tvbuff_t *tvb)
63 int offset = MIRROR_HDR_SZ; /* Point past the 8 byte mirror header */
64 int byte0, byte1, byte2, byte3;
66 /* The following section is designed to determine the nature of the mirrored packet.
68 * The first four bytes will be inspected to deduce the type of traffic.
69 * The bit pattern shown below is the basis. A bit of "x" is a variable field.
71 * IPv4 Header: 0100 0101 xxxx xx00 ==> Pattern for standard IPv4 20-byte header
72 * IPv6 Header: 0110 xxxx xxxx 0000 0000 0000 0000 0000 ==> Pattern for standard IPv6 header with no flow label
73 * PPP/HDLC: 1111 1111 0000 0011 xx00 0000 0010 0001 ==> HDLC-like framing for PPP (FF 03 x0 21)
76 if (!tvb_bytes_exist(tvb, offset, 4))
77 return NULL; /* Not enough bytes for heuristic test */
79 /* Filter for IPv4 and IPv6 packets */
80 byte0 = tvb_get_guint8(tvb, offset + 0);
81 byte1 = tvb_get_guint8(tvb, offset + 1);
82 byte2 = tvb_get_guint8(tvb, offset + 2);
83 byte3 = tvb_get_guint8(tvb, offset + 3);
85 /* Look for IPv4 with standard header length */
86 if ( byte0 == 0x45 && ipv4_handle )
90 else if ( hi_nibble(byte0) == 6 && lo_nibble(byte1) == 0 && byte2 == 0 && byte3 == 0 && ipv6_handle )
93 /* Look for PPP/HDLC */
94 else if ( byte0 == 0xff && byte1 == 0x03 && lo_nibble(byte2) == 0 && byte3 == 0x21 && hdlc_handle )
97 /* If it's something else entirely return nothing */
102 /* Heuristic UDP dissector called by Wireshark looking for embedded IPv4, IPv6 or L2TP/HDLC Jmirror packets */
104 dissect_jmirror(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
107 dissector_handle_t dissector_handle;
108 unsigned int midval, sidval;
109 proto_item *ti = NULL;
110 proto_tree *jmirror_tree = NULL;
111 tvbuff_t *next_tvb = NULL;
113 if ( !( dissector_handle = get_heuristic_handle(tvb) ) )
116 /* Populate the Protocol field in the Wireshark packet display */
117 col_set_str(pinfo->cinfo, COL_PROTOCOL, "Jmirror");
119 /* Build the Jmirror Identifier value and store the string in a buffer */
120 midval = tvb_get_ntohl(tvb, offset);
122 /* Build the Session Identifier value and store the string in a buffer */
123 sidval = tvb_get_ntohl(tvb, offset+MIRROR_ID_SZ);
125 /* Populate the Info field in the Wireshark packet display */
126 col_add_fstr(pinfo->cinfo, COL_INFO, "MID: 0X%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval);
128 /* Create a header for the Mirror Header in the protocol tree */
129 ti = proto_tree_add_protocol_format(tree, proto_jmirror, tvb, offset, MIRROR_HDR_SZ,
130 "Juniper Packet Mirror, MID: 0x%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval);
132 /* Add the Juniper Packet Mirror to the main protocol tree */
133 jmirror_tree = proto_item_add_subtree(ti, ett_jmirror);
135 /* Insert the Jmirror Identifier into the protocol tree and assign value to filter variable */
136 proto_tree_add_item(jmirror_tree, hf_jmirror_mid, tvb, offset, MIRROR_ID_SZ, FALSE);
138 /* Push the tvbuff_t offset pointer along to the Session Identifier */
139 offset += MIRROR_ID_SZ;
141 /* Insert the Session Identifier into the protocol tree and assign value to filter variable */
142 proto_tree_add_item(jmirror_tree, hf_jmirror_sid, tvb, offset, SESSION_ID_SZ, FALSE);
144 /* Push the tvbuff_t offset pointer along to the start of the mirrored packet */
145 offset += SESSION_ID_SZ;
147 /* Create a buffer pointer for the next dissector */
148 next_tvb = tvb_new_subset(tvb, offset, -1, -1);
150 /* Call the next dissector based on the heurstics and return the number of bytes dissected */
151 return MIRROR_HDR_SZ + call_dissector(dissector_handle, next_tvb, pinfo, tree);
155 /* Register Jmirror dissector with Wireshark */
157 proto_register_jmirror(void)
159 module_t *jmirror_module = NULL;
161 /* Used by the Expression dialog and filter box */
162 static hf_register_info jmirror_hf[] = {
164 { "Jmirror Identifier", "jmirror.mid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
165 "Unique identifier of the mirrored session", HFILL }
168 { "Session Identifier", "jmirror.sid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
169 "Unique identifier of the user session", HFILL }
172 static gint *jmirror_ett[] = {
176 /* Register the Jmirror protocol with Wireshark */
177 proto_jmirror = proto_register_protocol("Juniper Packet Mirror", "Jmirror", "jmirror");
179 /* Register the Jmirror preferences with Wireshark */
180 jmirror_module = prefs_register_protocol(proto_jmirror, proto_reg_handoff_jmirror);
182 /* Allow the user to set the UDP port for the decode under the Edit -> Preferences menu */
183 prefs_register_uint_preference(jmirror_module, "udp.port", "JMirror UDP Port",
184 "Set the port for JMirror Port (if other than the default of 30030)",
185 10, &global_jmirror_udp_port);
187 /* Register the Jmirror subfields for filters */
188 proto_register_field_array(proto_jmirror, jmirror_hf, array_length(jmirror_hf));
189 proto_register_subtree_array(jmirror_ett, array_length(jmirror_ett));
192 /* Create attachment point for dissector in Wireshark */
194 proto_reg_handoff_jmirror(void)
196 static int jmirror_inited = FALSE;
197 static guint jmirror_udp_port;
198 static dissector_handle_t jmirror_handle;
200 if ( !jmirror_inited )
202 /* register as heuristic dissector for UDP */
203 /* heur_dissector_add("udp", dissect_jmirror, proto_jmirror); */
205 /* Create a dissector handle for the Jmirror protocol */
206 jmirror_handle = new_create_dissector_handle(dissect_jmirror, proto_jmirror);
208 /* Create pointer to ipv4, ipv6, ppp and data dissectors */
209 ipv4_handle = find_dissector("ip");
210 ipv6_handle = find_dissector("ipv6");
211 hdlc_handle = find_dissector("pw_hdlc_nocw_hdlc_ppp");
213 /* Set the init flag */
214 jmirror_inited = TRUE;
216 /* Unregister from the old UDP port */
217 dissector_delete("udp.port", jmirror_udp_port, jmirror_handle);
220 jmirror_udp_port = global_jmirror_udp_port;
222 /* Register as a normal IP dissector with default UDP port 30030 */
223 dissector_add("udp.port", jmirror_udp_port, jmirror_handle);