/* packet-jmirror.c * Routines for Jmirror protocol packet disassembly * By Wayne Brassem * Copyright 2009 Wayne Brassem * 2012 Wayne Brassem - Correction to support IPv6 over PPP * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include void proto_register_jmirror(void); void proto_reg_handoff_jmirror(void); static dissector_handle_t jmirror_handle; #define MIRROR_HDR_SZ 8 #define MIRROR_ID_SZ 4 #define SESSION_ID_SZ 4 #define DEF_JMIRROR_UDP_PORT 30030 /* a product of primes (1*2*3*5*7*11*13) :-) Not IANA registered */ /* * See www.juniper.net JUNOSe Packet Mirroring documentation */ /* Jmirror protocol variables */ static int proto_jmirror; static int hf_jmirror_mid; static int hf_jmirror_sid; static int ett_jmirror; /* Handles which point to the packet dissectors */ static dissector_handle_t ipv4_handle; static dissector_handle_t ipv6_handle; static dissector_handle_t hdlc_handle; /* Routine to return the dissector handle based on heuristic packet inspection */ static dissector_handle_t get_heuristic_handle(tvbuff_t *tvb) { int offset = MIRROR_HDR_SZ; /* Point past the 8 byte mirror header */ int byte0, byte1, byte2, byte3; /* The following section is designed to determine the nature of the mirrored packet. * * The first four bytes will be inspected to deduce the type of traffic. * The bit pattern shown below is the basis. A bit of "x" is a variable field. * * IPv4 Header: 0100 0101 xxxx xx00 ==> Pattern for standard IPv4 20-byte header * IPv6 Header: 0110 xxxx xxxx xxxx xxxx xxxx xxxx xxxx ==> Pattern for standard IPv6 header with variable TC and Flow * PPP/HDLC: 1111 1111 0000 0011 xx00 0000 0010 0001 ==> HDLC-like framing for PPP (FF 03 x0 21) * PPP/HDLC: 1111 1111 0000 0011 0000 0000 0101 0111 ==> HDLC-like framing for PPP IPv6 (FF 03 00 57) */ if (!tvb_bytes_exist(tvb, offset, 4)) return NULL; /* Not enough bytes for heuristic test */ /* Filter for IPv4 and IPv6 packets */ byte0 = tvb_get_uint8(tvb, offset + 0); byte1 = tvb_get_uint8(tvb, offset + 1); byte2 = tvb_get_uint8(tvb, offset + 2); byte3 = tvb_get_uint8(tvb, offset + 3); /* Look for IPv4 with standard header length */ if ( byte0 == 0x45 && ipv4_handle ) return ipv4_handle; /* Look for IPv6 */ else if ( hi_nibble(byte0) == 6 && ipv6_handle ) return ipv6_handle; /* Look for PPP/HDLC for LCP and IPv4 */ else if ( byte0 == 0xff && byte1 == 0x03 && lo_nibble(byte2) == 0 && byte3 == 0x21 && hdlc_handle ) return hdlc_handle; /* Look for PPP/HDLC for IPv6 */ else if ( byte0 == 0xff && byte1 == 0x03 && byte2 == 0 && byte3 == 0x57 && hdlc_handle ) return hdlc_handle; /* If it's something else entirely return nothing */ else return NULL; } /* Heuristic UDP dissector called by Wireshark looking for embedded IPv4, IPv6 or L2TP/HDLC Jmirror packets */ static int dissect_jmirror(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { int offset = 0; dissector_handle_t dissector_handle; unsigned int midval, sidval; proto_item *ti = NULL; proto_tree *jmirror_tree = NULL; tvbuff_t *next_tvb = NULL; if ( !( dissector_handle = get_heuristic_handle(tvb) ) ) return 0; /* Populate the Protocol field in the Wireshark packet display */ col_set_str(pinfo->cinfo, COL_PROTOCOL, "Jmirror"); /* Build the Jmirror Identifier value and store the string in a buffer */ midval = tvb_get_ntohl(tvb, offset); /* Build the Session Identifier value and store the string in a buffer */ sidval = tvb_get_ntohl(tvb, offset+MIRROR_ID_SZ); /* Populate the Info field in the Wireshark packet display */ col_add_fstr(pinfo->cinfo, COL_INFO, "MID: 0X%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval); /* Create a header for the Mirror Header in the protocol tree */ ti = proto_tree_add_protocol_format(tree, proto_jmirror, tvb, offset, MIRROR_HDR_SZ, "Juniper Packet Mirror, MID: 0x%08x (%d), SID: 0x%08x (%d)", midval, midval, sidval, sidval); /* Add the Juniper Packet Mirror to the main protocol tree */ jmirror_tree = proto_item_add_subtree(ti, ett_jmirror); /* Insert the Jmirror Identifier into the protocol tree and assign value to filter variable */ proto_tree_add_item(jmirror_tree, hf_jmirror_mid, tvb, offset, MIRROR_ID_SZ, ENC_BIG_ENDIAN); /* Push the tvbuff_t offset pointer along to the Session Identifier */ offset += MIRROR_ID_SZ; /* Insert the Session Identifier into the protocol tree and assign value to filter variable */ proto_tree_add_item(jmirror_tree, hf_jmirror_sid, tvb, offset, SESSION_ID_SZ, ENC_BIG_ENDIAN); /* Push the tvbuff_t offset pointer along to the start of the mirrored packet */ offset += SESSION_ID_SZ; /* Create a buffer pointer for the next dissector */ next_tvb = tvb_new_subset_remaining(tvb, offset); /* Call the next dissector based on the heuristics and return the number of bytes dissected */ return MIRROR_HDR_SZ + call_dissector(dissector_handle, next_tvb, pinfo, tree); } /* Register Jmirror dissector with Wireshark */ void proto_register_jmirror(void) { /* Used by the Expression dialog and filter box */ static hf_register_info jmirror_hf[] = { { &hf_jmirror_mid, { "Jmirror Identifier", "jmirror.mid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0, "Unique identifier of the mirrored session", HFILL } }, { &hf_jmirror_sid, { "Session Identifier", "jmirror.sid", FT_UINT32, BASE_HEX_DEC, NULL, 0x0, "Unique identifier of the user session", HFILL } } }; static int *jmirror_ett[] = { &ett_jmirror }; /* Register the Jmirror protocol with Wireshark */ proto_jmirror = proto_register_protocol("Juniper Packet Mirror", "Jmirror", "jmirror"); /* Register the Jmirror subfields for filters */ proto_register_field_array(proto_jmirror, jmirror_hf, array_length(jmirror_hf)); proto_register_subtree_array(jmirror_ett, array_length(jmirror_ett)); /* Create a dissector handle for the Jmirror protocol */ jmirror_handle = register_dissector("jmirror", dissect_jmirror, proto_jmirror); } /* Create attachment point for dissector in Wireshark */ void proto_reg_handoff_jmirror(void) { /* register as heuristic dissector for UDP */ /* heur_dissector_add("udp", dissect_jmirror, proto_jmirror); */ /* Create pointer to ipv4, ipv6, ppp and data dissectors */ ipv4_handle = find_dissector_add_dependency("ip", proto_jmirror); ipv6_handle = find_dissector_add_dependency("ipv6", proto_jmirror); hdlc_handle = find_dissector_add_dependency("pw_hdlc_nocw_hdlc_ppp", proto_jmirror); /* Register as a normal IP dissector with default UDP port 30030 */ dissector_add_uint_with_preference("udp.port", DEF_JMIRROR_UDP_PORT, jmirror_handle); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 8 * tab-width: 8 * indent-tabs-mode: t * End: * * vi: set shiftwidth=8 tabstop=8 noexpandtab: * :indentSize=8:tabSize=8:noTabs=false: */