![Bill Meier](/assets/img/avatar_default.png)
Registering the dissector publicly doesn't seem to be needed; Fix a typo in a comment and also some indentation. svn path=/trunk/; revision=30784
225 lines
7.8 KiB
C
225 lines
7.8 KiB
C
/* packet-jmirror.c
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* Routines for Jmirror protocol packet disassembly
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* By Wayne Brassem <wbrassem@juniper.net>
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* Copyright 2009 Wayne Brassem
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*
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* $Id$
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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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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#define MIRROR_HDR_SZ 8
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#define MIRROR_ID_SZ 4
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#define SESSION_ID_SZ 4
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#define DEF_JMIRROR_UDP_PORT 30030 /* a product of primes (1*2*3*5*7*11*13) :-) */
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/*
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* See www.juniper.net JUNOSe Packet Mirroring documentation
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*/
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/* Jmirror protocol variables */
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static int proto_jmirror = -1;
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static int hf_jmirror_mid = -1;
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static int hf_jmirror_sid = -1;
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static gint ett_jmirror = -1;
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/* Handles which point to the packet dissectors */
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static dissector_handle_t ipv4_handle;
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static dissector_handle_t ipv6_handle;
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static dissector_handle_t hdlc_handle;
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static guint global_jmirror_udp_port = DEF_JMIRROR_UDP_PORT;
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/* Forward declaration */
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void proto_reg_handoff_jmirror(void);
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/* Routine to return the dissector handle based on heuristic packet inspection */
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static dissector_handle_t
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get_heuristic_handle(tvbuff_t *tvb)
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{
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int offset = MIRROR_HDR_SZ; /* Point past the 8 byte mirror header */
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int byte0, byte1, byte2, byte3;
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/* The following section is designed to determine the nature of the mirrored packet.
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*
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* The first four bytes will be inspected to deduce the type of traffic.
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* The bit pattern shown below is the basis. A bit of "x" is a variable field.
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*
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* IPv4 Header: 0100 0101 xxxx xx00 ==> Pattern for standard IPv4 20-byte header
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* IPv6 Header: 0110 xxxx xxxx 0000 0000 0000 0000 0000 ==> Pattern for standard IPv6 header with no flow label
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* PPP/HDLC: 1111 1111 0000 0011 xx00 0000 0010 0001 ==> HDLC-like framing for PPP (FF 03 x0 21)
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*/
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if (!tvb_bytes_exist(tvb, offset, 4))
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return NULL; /* Not enough bytes for heuristic test */
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/* Filter for IPv4 and IPv6 packets */
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byte0 = tvb_get_guint8(tvb, offset + 0);
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byte1 = tvb_get_guint8(tvb, offset + 1);
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byte2 = tvb_get_guint8(tvb, offset + 2);
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byte3 = tvb_get_guint8(tvb, offset + 3);
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/* Look for IPv4 with standard header length */
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if ( byte0 == 0x45 && ipv4_handle )
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return ipv4_handle;
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/* Look for IPv6 */
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else if ( hi_nibble(byte0) == 6 && lo_nibble(byte1) == 0 && byte2 == 0 && byte3 == 0 && ipv6_handle )
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return ipv6_handle;
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/* Look for PPP/HDLC */
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else if ( byte0 == 0xff && byte1 == 0x03 && lo_nibble(byte2) == 0 && byte3 == 0x21 && hdlc_handle )
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return hdlc_handle;
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/* If it's something else entirely return nothing */
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else
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return NULL;
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}
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/* Heuristic UDP dissector called by Wireshark looking for embedded IPv4, IPv6 or L2TP/HDLC Jmirror packets */
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static int
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dissect_jmirror(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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int offset = 0;
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dissector_handle_t dissector_handle;
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unsigned int midval, sidval;
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proto_item *ti = NULL;
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proto_tree *jmirror_tree = NULL;
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tvbuff_t *next_tvb = NULL;
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if ( !( dissector_handle = get_heuristic_handle(tvb) ) )
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return 0;
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/* Populate the Protocol field in the Wireshark packet display */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "Jmirror");
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/* Build the Jmirror Identifier value and store the string in a buffer */
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midval = tvb_get_ntohl(tvb, offset);
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/* Build the Session Identifier value and store the string in a buffer */
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sidval = tvb_get_ntohl(tvb, offset+MIRROR_ID_SZ);
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/* Populate the Info field in the Wireshark packet display */
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col_add_fstr(pinfo->cinfo, COL_INFO, "MID: 0X%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval);
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/* Create a header for the Mirror Header in the protocol tree */
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ti = proto_tree_add_protocol_format(tree, proto_jmirror, tvb, offset, MIRROR_HDR_SZ,
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"Juniper Packet Mirror, MID: 0x%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval);
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/* Add the Juniper Packet Mirror to the main protocol tree */
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jmirror_tree = proto_item_add_subtree(ti, ett_jmirror);
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/* Insert the Jmirror Identifier into the protocol tree and assign value to filter variable */
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proto_tree_add_item(jmirror_tree, hf_jmirror_mid, tvb, offset, MIRROR_ID_SZ, FALSE);
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/* Push the tvbuff_t offset pointer along to the Session Identifier */
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offset += MIRROR_ID_SZ;
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/* Insert the Session Identifier into the protocol tree and assign value to filter variable */
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proto_tree_add_item(jmirror_tree, hf_jmirror_sid, tvb, offset, SESSION_ID_SZ, FALSE);
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/* Push the tvbuff_t offset pointer along to the start of the mirrored packet */
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offset += SESSION_ID_SZ;
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/* Create a buffer pointer for the next dissector */
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next_tvb = tvb_new_subset(tvb, offset, -1, -1);
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/* Call the next dissector based on the heurstics and return the number of bytes dissected */
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return MIRROR_HDR_SZ + call_dissector(dissector_handle, next_tvb, pinfo, tree);
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}
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/* Register Jmirror dissector with Wireshark */
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void
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proto_register_jmirror(void)
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{
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module_t *jmirror_module = NULL;
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/* Used by the Expression dialog and filter box */
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static hf_register_info jmirror_hf[] = {
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{ &hf_jmirror_mid,
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{ "Jmirror Identifier", "jmirror.mid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
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"Unique identifier of the mirrored session", HFILL }
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},
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{ &hf_jmirror_sid,
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{ "Session Identifier", "jmirror.sid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0,
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"Unique identifier of the user session", HFILL }
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}
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};
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static gint *jmirror_ett[] = {
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&ett_jmirror
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};
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/* Register the Jmirror protocol with Wireshark */
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proto_jmirror = proto_register_protocol("Juniper Packet Mirror", "Jmirror", "jmirror");
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/* Register the Jmirror preferences with Wireshark */
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jmirror_module = prefs_register_protocol(proto_jmirror, proto_reg_handoff_jmirror);
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/* Allow the user to set the UDP port for the decode under the Edit -> Preferences menu */
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prefs_register_uint_preference(jmirror_module, "udp.port", "JMirror UDP Port",
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"Set the port for JMirror Port (if other than the default of 30030)",
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10, &global_jmirror_udp_port);
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/* Register the Jmirror subfields for filters */
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proto_register_field_array(proto_jmirror, jmirror_hf, array_length(jmirror_hf));
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proto_register_subtree_array(jmirror_ett, array_length(jmirror_ett));
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}
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/* Create attachment point for dissector in Wireshark */
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void
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proto_reg_handoff_jmirror(void)
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{
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static int jmirror_inited = FALSE;
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static guint jmirror_udp_port;
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static dissector_handle_t jmirror_handle;
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if ( !jmirror_inited )
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{
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/* register as heuristic dissector for UDP */
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/* heur_dissector_add("udp", dissect_jmirror, proto_jmirror); */
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/* Create a dissector handle for the Jmirror protocol */
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jmirror_handle = new_create_dissector_handle(dissect_jmirror, proto_jmirror);
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/* Create pointer to ipv4, ipv6, ppp and data dissectors */
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ipv4_handle = find_dissector("ip");
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ipv6_handle = find_dissector("ipv6");
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hdlc_handle = find_dissector("pw_hdlc_nocw_hdlc_ppp");
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/* Set the init flag */
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jmirror_inited = TRUE;
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} else {
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/* Unregister from the old UDP port */
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dissector_delete("udp.port", jmirror_udp_port, jmirror_handle);
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}
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jmirror_udp_port = global_jmirror_udp_port;
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/* Register as a normal IP dissector with default UDP port 30030 */
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dissector_add("udp.port", jmirror_udp_port, jmirror_handle);
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}
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