165 lines
5.2 KiB
C
165 lines
5.2 KiB
C
/* packet-ieee8021CB.c
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* Routines for 802.1CB R-tag ethernet header disassembly
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*
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* Copyright 2020, Rene Nielsen <rene.nielsen@microchip.com>
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* In association with Microchip Technology Inc.
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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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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/capture_dissectors.h>
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#include <wsutil/pint.h>
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#include <epan/addr_resolv.h>
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#include "packet-ipx.h"
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#include "packet-llc.h"
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#include <epan/etypes.h>
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#include <epan/prefs.h>
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void proto_register_ieee8021cb(void);
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void proto_reg_handoff_ieee8021cb(void);
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static dissector_handle_t ethertype_handle;
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static capture_dissector_handle_t ipx_cap_handle;
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static capture_dissector_handle_t llc_cap_handle;
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/* GLOBALS ************************************************************/
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static int proto_ieee8021cb = -1;
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/* dot1cb R-tag fields */
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static int hf_ieee8021cb_res = -1;
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static int hf_ieee8021cb_seq = -1;
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/* Encapsulated protocol */
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static int hf_ieee8021cb_etype = -1;
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static gint ett_ieee8021cb = -1;
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#define IEEE8021CB_LEN 6
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static gboolean
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capture_ieee8021cb(const guchar *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header)
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{
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guint16 encap_proto;
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if (!BYTES_ARE_IN_FRAME(offset, len, IEEE8021CB_LEN + 1))
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return FALSE;
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encap_proto = pntoh16( &pd[offset + IEEE8021CB_LEN - 2] );
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if (encap_proto <= IEEE_802_3_MAX_LEN) {
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if ( pd[offset + IEEE8021CB_LEN] == 0xff
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&& pd[offset + IEEE8021CB_LEN + 1] == 0xff ) {
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return call_capture_dissector(ipx_cap_handle, pd, offset + IEEE8021CB_LEN, len, cpinfo, pseudo_header);
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}
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else {
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return call_capture_dissector(llc_cap_handle, pd, offset + IEEE8021CB_LEN, len, cpinfo, pseudo_header);
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}
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}
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return try_capture_dissector("ethertype", encap_proto, pd, offset + IEEE8021CB_LEN, len, cpinfo, pseudo_header);
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}
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/* Dissector *************************************************************/
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static
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int dissect_ieee8021cb(tvbuff_t *tvb, packet_info *pinfo,
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proto_tree *tree, void* data _U_)
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{
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proto_tree *ptree = NULL;
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guint16 seq, pro;
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ethertype_data_t ethertype_data;
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proto_tree *ieee8021cb_tree;
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/* add info to column display */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "802.1CB R-Tag");
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col_clear(pinfo->cinfo, COL_INFO);
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seq = tvb_get_ntohs(tvb, 2);
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pro = tvb_get_ntohs(tvb, 4);
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col_add_fstr(pinfo->cinfo, COL_INFO, "SEQ: %u", seq);
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/* create the protocol tree */
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ptree = proto_tree_add_item(tree, proto_ieee8021cb, tvb, 0, IEEE8021CB_LEN, ENC_NA);
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ieee8021cb_tree = proto_item_add_subtree(ptree, ett_ieee8021cb);
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/* add fields */
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proto_tree_add_uint(ieee8021cb_tree, hf_ieee8021cb_seq, tvb, 2, 2, seq);
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proto_tree_add_uint(ieee8021cb_tree, hf_ieee8021cb_etype, tvb, 4, 2, pro);
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proto_item_append_text(ptree, ", SEQ: %u", seq);
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ethertype_data.fh_tree = ieee8021cb_tree;
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ethertype_data.fcs_len = 0;
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ethertype_data.etype = pro;
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ethertype_data.payload_offset = IEEE8021CB_LEN;
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/* 802.1CB tags are always followed by an ethertype; call next dissector
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based on ethertype */
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call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, ðertype_data);
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return tvb_captured_length(tvb);
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}
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void
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proto_register_ieee8021cb(void)
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{
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static hf_register_info hf_1cb[] = {
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{ &hf_ieee8021cb_res, {
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"Reserved", "ieee8021cb.reserved", FT_UINT16, BASE_HEX,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_ieee8021cb_seq, {
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"SEQ", "ieee8021cb.seq", FT_UINT16, BASE_HEX_DEC,
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NULL, 0x0, NULL, HFILL }},
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{ &hf_ieee8021cb_etype, {
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"Type", "ieee8021cb.etype", FT_UINT16, BASE_HEX,
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VALS(etype_vals), 0x0, "Ethertype", HFILL }}
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};
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static gint *ett[] = {
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&ett_ieee8021cb
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};
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/* registration */
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proto_ieee8021cb = proto_register_protocol("802.1CB Redundancy Tag", "R-Tag", "ieee8021cb");
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proto_register_field_array(proto_ieee8021cb, hf_1cb, array_length(hf_1cb));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_ieee8021cb(void)
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{
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static dissector_handle_t ieee8021cb_handle;
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static capture_dissector_handle_t ieee8021cb_cap_handle;
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ieee8021cb_handle = create_dissector_handle(dissect_ieee8021cb, proto_ieee8021cb);
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dissector_add_uint("ethertype", ETHERTYPE_IEEE_802_1CB, ieee8021cb_handle);
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ethertype_handle = find_dissector_add_dependency("ethertype", proto_ieee8021cb);
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ieee8021cb_cap_handle = create_capture_dissector_handle(capture_ieee8021cb, proto_ieee8021cb);
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capture_dissector_add_uint("ethertype", ETHERTYPE_IEEE_802_1CB, ieee8021cb_cap_handle);
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ipx_cap_handle = find_capture_dissector("ipx");
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llc_cap_handle = find_capture_dissector("llc");
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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