194 lines
5.4 KiB
C
194 lines
5.4 KiB
C
/* packet-vntag.c
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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/etypes.h>
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#include <epan/expert.h>
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#include <epan/tfs.h>
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#include <epan/dissectors/packet-ieee8023.h>
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void proto_register_vntag(void);
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void proto_reg_handoff_vntag(void);
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static dissector_handle_t ethertype_handle;
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static int proto_vntag = -1;
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static int hf_vntag_etype = -1;
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static int hf_vntag_dir = -1;
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static int hf_vntag_ptr = -1;
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static int hf_vntag_dst = -1;
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static int hf_vntag_looped = -1;
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static int hf_vntag_r = -1;
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static int hf_vntag_version = -1;
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static int hf_vntag_src = -1;
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static int hf_vntag_len = -1;
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static int hf_vntag_trailer = -1;
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static gint ett_vntag = -1;
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static expert_field ei_vntag_len = EI_INIT;
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static const true_false_string vntag_dir_tfs = {
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"From Bridge",
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"To Bridge"
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};
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static const true_false_string vntag_ptr_tfs = {
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"vif_list_id",
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"vif_id"
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};
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static int
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dissect_vntag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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guint16 encap_proto;
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proto_tree *vntag_tree = NULL;
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ethertype_data_t ethertype_data;
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/* Documentation:
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https://d2zmdbbm9feqrf.cloudfront.net/2012/usa/pdf/BRKDCT-2340.pdf p.61
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http://www.definethecloud.net/access-layer-network-virtualization-vn-tag-and-vepa
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*/
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static int * const fields[] = {
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&hf_vntag_dir,
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&hf_vntag_ptr,
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&hf_vntag_dst,
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&hf_vntag_looped,
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&hf_vntag_r,
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&hf_vntag_version,
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&hf_vntag_src,
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NULL
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};
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "VNTAG");
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col_clear(pinfo->cinfo, COL_INFO);
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if (tree) {
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proto_item *ti = proto_tree_add_item(tree, proto_vntag, tvb, 0, 4, ENC_NA);
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vntag_tree = proto_item_add_subtree(ti, ett_vntag);
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proto_tree_add_bitmask_list(vntag_tree, tvb, 0, 4, fields, ENC_BIG_ENDIAN);
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}
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encap_proto = tvb_get_ntohs(tvb, 4);
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/* VNTAG may also carry 802.2 encapsulated data */
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if (encap_proto <= IEEE_802_3_MAX_LEN) {
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gboolean is_802_2;
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/* Is there an 802.2 layer? I can tell by looking at the first 2
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bytes after the VLAN header. If they are 0xffff, then what
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follows the VLAN header is an IPX payload, meaning no 802.2.
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(IPX/SPX is they only thing that can be contained inside a
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straight 802.3 packet, so presumably the same applies for
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Ethernet VLAN packets). A non-0xffff value means that there's an
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802.2 layer inside the VLAN layer */
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is_802_2 = TRUE;
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/* Don't throw an exception for this check (even a BoundsError) */
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if (tvb_captured_length_remaining(tvb, 6) >= 2) {
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if (tvb_get_ntohs(tvb, 6) == 0xffff)
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is_802_2 = FALSE;
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}
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dissect_802_3(encap_proto, is_802_2, tvb, 6, pinfo, tree, vntag_tree, hf_vntag_len, hf_vntag_trailer, &ei_vntag_len, 0);
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} else {
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proto_tree_add_uint(vntag_tree, hf_vntag_etype, tvb, 4, 2,
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encap_proto);
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ethertype_data.etype = encap_proto;
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ethertype_data.payload_offset = 6;
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ethertype_data.fh_tree = vntag_tree;
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ethertype_data.trailer_id = hf_vntag_trailer;
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ethertype_data.fcs_len = 0;
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call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, ðertype_data);
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}
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return tvb_captured_length(tvb);
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}
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void
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proto_register_vntag(void)
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{
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static hf_register_info hf[] = {
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{ &hf_vntag_etype,
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{ "Type", "vntag.etype", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, NULL, HFILL }
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},
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{ &hf_vntag_dir,
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{ "Direction", "vntag.dir", FT_BOOLEAN, 32, TFS(&vntag_dir_tfs), 0x80000000, NULL, HFILL }
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},
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{ &hf_vntag_ptr,
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{ "Pointer", "vntag.ptr", FT_BOOLEAN, 32, TFS(&vntag_ptr_tfs), 0x40000000, NULL, HFILL }
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},
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{ &hf_vntag_dst,
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{ "Destination", "vntag.dst", FT_UINT32, BASE_DEC, NULL, 0x3FFF0000, NULL, HFILL }
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},
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{ &hf_vntag_looped,
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{ "Looped", "vntag.looped", FT_BOOLEAN, 32, TFS(&tfs_yes_no), 0x00008000, NULL, HFILL }
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},
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{ &hf_vntag_r,
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{ "Reserved", "vntag.r", FT_UINT32, BASE_DEC, NULL, 0x00004000, NULL, HFILL }
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},
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{ &hf_vntag_version,
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{ "Version", "vntag.version", FT_UINT32, BASE_DEC, NULL, 0x00003000, NULL, HFILL }
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},
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{ &hf_vntag_src,
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{ "Source", "vntag.src", FT_UINT32, BASE_DEC, NULL, 0x00000FFF, NULL, HFILL }
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},
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{ &hf_vntag_len,
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{ "Length", "vntag.len", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }
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},
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{ &hf_vntag_trailer,
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{ "Trailer", "vntag.trailer", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }
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}
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};
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static gint *ett[] = {
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&ett_vntag
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};
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static ei_register_info ei[] = {
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{ &ei_vntag_len, { "vntag.len.past_end", PI_MALFORMED, PI_ERROR, "Length field value goes past the end of the payload", EXPFILL }},
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};
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expert_module_t* expert_vntag;
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proto_vntag = proto_register_protocol("VN-Tag", "VNTAG", "vntag");
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proto_register_field_array(proto_vntag, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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expert_vntag = expert_register_protocol(proto_vntag);
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expert_register_field_array(expert_vntag, ei, array_length(ei));
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}
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void
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proto_reg_handoff_vntag(void)
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{
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dissector_handle_t vntag_handle;
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vntag_handle = create_dissector_handle(dissect_vntag, proto_vntag);
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dissector_add_uint("ethertype", ETHERTYPE_VNTAG, vntag_handle);
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ethertype_handle = find_dissector_add_dependency("ethertype", proto_vntag);
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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: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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