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/* packet-cisco-metadata.c
* Routines for dissection of Cisco's MetaData protocol.
* draft-smith-kandula-sxp
* Copyright 2013 by Vaibhav Katkade (vkatkade[AT]cisco.com)
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/etypes.h>
#if 0
#include "packet-ieee8023.h"
#endif
void proto_register_cmd(void);
void proto_reg_handoff_cmd(void);
static dissector_handle_t cmd_eth_handle;
static dissector_handle_t cmd_gre_handle;
static dissector_handle_t ethertype_handle;
static dissector_table_t gre_dissector_table;
static int proto_cmd;
static int hf_cmd_version;
static int hf_cmd_length;
static int hf_cmd_options;
static int hf_cmd_sgt;
static int hf_eth_type;
static int hf_cmd_trailer;
static int ett_cmd;
static int
dissect_cmd_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
uint16_t encap_proto;
ethertype_data_t ethertype_data;
proto_tree *cmd_tree = NULL;
int offset = 0;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CMD");
col_clear(pinfo->cinfo, COL_INFO);
if (tree) {
proto_item *ti = proto_tree_add_item(tree, proto_cmd, tvb, 0, 8, ENC_NA);
cmd_tree = proto_item_add_subtree(ti, ett_cmd);
proto_tree_add_item(cmd_tree, hf_cmd_version, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item(cmd_tree, hf_cmd_length, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item(cmd_tree, hf_cmd_options, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cmd_tree, hf_cmd_sgt, tvb, offset, 2, ENC_BIG_ENDIAN);
/*offset += 2;*/
}
encap_proto = tvb_get_ntohs(tvb, 6);
/* This Logic to identify and decode IEEE 802.3 frames is not working correctly. Carry over code from packet-vlan.c
* Commenting it out for now will display as Unknown for L2 control frames instead of showing a wrong decode.
*/
#if 0
if (encap_proto <= IEEE_802_3_MAX_LEN) {
bool is_802_2 = true;
/* Don't throw an exception for this check (even a BoundsError) */
if (tvb_captured_length_remaining(tvb, 4) >= 2) {
if (tvb_get_ntohs(tvb, 4) == 0xffff)
is_802_2 = false;
}
dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, cmd_tree, hf_eth_type, hf_cmd_trailer, 0);
} else {
#endif
proto_tree_add_uint(cmd_tree, hf_eth_type, tvb, 6, 2, encap_proto);
ethertype_data.etype = encap_proto;
ethertype_data.payload_offset = 8;
ethertype_data.fh_tree = cmd_tree;
ethertype_data.trailer_id = hf_cmd_trailer;
ethertype_data.fcs_len = 0;
call_dissector_with_data(ethertype_handle, tvb, pinfo, tree, ðertype_data);
return tvb_captured_length(tvb);
}
static int
dissect_cmd_gre(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
proto_item *ti = NULL;
proto_tree *cmd_tree = NULL;
uint16_t encap_proto;
tvbuff_t *next_tvb;
int offset = 0;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CMD");
col_clear(pinfo->cinfo, COL_INFO);
if (tree) {
ti = proto_tree_add_item(tree, proto_cmd, tvb, 0, 6, ENC_NA);
cmd_tree = proto_item_add_subtree(ti, ett_cmd);
}
encap_proto = tvb_get_ntohs(tvb, 0);
proto_tree_add_item(cmd_tree, hf_eth_type, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cmd_tree, hf_cmd_version, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item(cmd_tree, hf_cmd_length, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
proto_tree_add_item(cmd_tree, hf_cmd_options, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(cmd_tree, hf_cmd_sgt, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
next_tvb = tvb_new_subset_remaining(tvb, offset);
if (!dissector_try_uint(gre_dissector_table, encap_proto, next_tvb, pinfo, tree))
call_data_dissector(next_tvb, pinfo, tree);
return tvb_captured_length(tvb);
}
void
proto_register_cmd(void)
{
static hf_register_info hf[] = {
{ &hf_cmd_version,
{ "Version", "cmd.version", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }
},
{ &hf_cmd_length,
{ "Length", "cmd.length", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }
},
{ &hf_cmd_options,
{ "Options", "cmd.options", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }
},
{ &hf_cmd_sgt,
{ "SGT", "cmd.sgt", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }
},
{ &hf_eth_type,
{ "Type", "cmd.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0, NULL, HFILL }
},
{ &hf_cmd_trailer,
{ "Trailer", "cmd.trailer", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }
},
};
static int *ett[] = {
&ett_cmd
};
proto_cmd = proto_register_protocol("Cisco MetaData", "Cisco MetaData", "cmd");
proto_register_field_array(proto_cmd, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
cmd_eth_handle = register_dissector("cmd.eth", dissect_cmd_eth, proto_cmd);
cmd_gre_handle = register_dissector("cmd.gre", dissect_cmd_gre, proto_cmd);
}
void
proto_reg_handoff_cmd(void)
{
ethertype_handle = find_dissector_add_dependency("ethertype", proto_cmd);
gre_dissector_table = find_dissector_table("gre.proto");
dissector_add_uint("ethertype", ETHERTYPE_CMD, cmd_eth_handle);
dissector_add_uint("gre.proto", ETHERTYPE_CMD, cmd_gre_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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