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wireshark/epan/dissectors/packet-nsh.c

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/*Routines for Network Service Header
*draft-ietf-sfc-nsh-01
*Author: Chidambaram Arunachalam <carunach@cisco.com>
*Copyright 2016, ciscoSystems Inc.
*
*
*Wireshark - Network traffic analyzer
*By Gerald Combs <gerald@wireshark.org>
*Copyright 1998 Gerald Combs
*
*(c) Copyright 2016, Sumit Kumar Jha <sjha3@ncsu.edu>
*Support for VXLAN GPE encapsulation
*
*This program is free software; you can redistribute it and/or
*modify it under the terms of the GNU General Public License
*as published by the Free Software Foundation; either version 2
*of the License, or (at your option) any later version.
*
*This program is distributed in the hope that it will be useful,
*but WITHOUT ANY WARRANTY; without even the implied warranty of
*MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
*GNU General Public License for more details.
*
*You should have received a copy of the GNU General Public License
*along with this program; if not, write to the Free Software
*Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/ppptypes.h>
#include <epan/etypes.h>
#include <epan/prefs.h>
#include <epan/ipproto.h>
#include <epan/decode_as.h>
#include "packet-vxlan.h"
#define MD_TYPE_1 1
#define MD_TYPE_2 2
/* Prototypes */
void proto_reg_handoff_nsh(void);
void proto_register_nsh(void);
/*Network Service Header (NSH) Next Protocol field values */
enum {
NSH_IPV4 = 1,
NSH_IPV6,
NSH_ETHERNET,
NSH_EXPERIMENTAL
};
static const value_string nsh_next_protocols[] = {
{ NSH_IPV4, "IPv4" },
{ NSH_IPV6, "IPv6" },
{ NSH_ETHERNET, "Ethernet" },
{ NSH_EXPERIMENTAL, "Experimental" },
{ 0, NULL }
};
static int proto_nsh = -1;
static int hf_nsh_version = -1;
static int hf_nsh_oam = -1;
static int hf_nsh_critical_metadata = -1;
static int hf_nsh_reservedbits = -1;
static int hf_nsh_length = -1;
static int hf_nsh_md_type = -1;
static int hf_nsh_next_proto = -1;
static int hf_nsh_service_pathID = -1;
static int hf_nsh_service_index = -1;
static int hf_nsh_context_header = -1;
static int hf_nsh_metadata_class = -1;
static int hf_nsh_metadata_type = -1;
static int hf_nsh_metadata_reservedbits = -1;
static int hf_nsh_metadata_length = -1;
static int hf_nsh_metadata = -1;
static gint ett_nsh = -1;
static dissector_handle_t dissector_ipv6;
static dissector_handle_t dissector_ip;
static dissector_handle_t dissector_eth;
/*
*Dissect Fixed Length Context headers
*
*/
static void
dissect_nsh_md_type_1(tvbuff_t *tvb, proto_tree *nsh_tree, int offset)
{
proto_tree_add_item(nsh_tree, hf_nsh_context_header, tvb, offset, 4, ENC_NA);
proto_tree_add_item(nsh_tree, hf_nsh_context_header, tvb, offset + 4, 4, ENC_NA);
proto_tree_add_item(nsh_tree, hf_nsh_context_header, tvb, offset + 8, 4, ENC_NA);
proto_tree_add_item(nsh_tree, hf_nsh_context_header, tvb, offset + 12, 4, ENC_NA);
}
/*
*Dissect Variable Length Context headers
*
*/
static void
dissect_nsh_md_type_2(tvbuff_t *tvb, proto_tree *nsh_tree, int offset, int nsh_bytes_len)
{
int type2_metadata_len = 0;
while (offset < nsh_bytes_len) {
proto_tree_add_item(nsh_tree, hf_nsh_metadata_class, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(nsh_tree, hf_nsh_metadata_type, tvb, offset + 2, 1, ENC_BIG_ENDIAN);
/* Bits 24 - 26 are reserved */
proto_tree_add_item(nsh_tree, hf_nsh_metadata_reservedbits, tvb, offset + 3, 1, ENC_BIG_ENDIAN);
/*Bits 27-31 represent length in 4 bytes words*/
proto_tree_add_item(nsh_tree, hf_nsh_metadata_length, tvb, offset + 3, 1, ENC_BIG_ENDIAN);
type2_metadata_len = 4 * tvb_get_bits8(tvb, ((offset + 3) * 8) + 3, 5);
if (type2_metadata_len >= 4)
proto_tree_add_item(nsh_tree, hf_nsh_metadata, tvb, offset + 4, type2_metadata_len, ENC_NA);
offset = offset + 4 + type2_metadata_len;
}
}
/*
*Dissect Network Service Header
*
*/
static int
dissect_nsh(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
int offset = 0;
int md_type = -1;
int nsh_bytes_len = 0;
int nsh_next_proto = -1;
int captured_length;
tvbuff_t *next_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "NSH");
col_set_str(pinfo->cinfo, COL_INFO, "Network Service Header");
captured_length = tvb_captured_length(tvb);
if (tree) {
proto_item *ti;
proto_tree *nsh_tree;
/* Bits 10 - 15 contain length value */
nsh_bytes_len = 4 * tvb_get_bits8(tvb, 10, 6);
ti = proto_tree_add_item(tree, proto_nsh, tvb, offset, nsh_bytes_len, ENC_NA);
nsh_tree = proto_item_add_subtree(ti, ett_nsh);
/*NSH Base Header*/
proto_tree_add_item(nsh_tree, hf_nsh_version, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(nsh_tree, hf_nsh_oam, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(nsh_tree, hf_nsh_critical_metadata, tvb, offset, 2, ENC_BIG_ENDIAN);
/* Bits 4 - 9 are reserved */
proto_tree_add_item(nsh_tree, hf_nsh_reservedbits, tvb, offset, 2, ENC_BIG_ENDIAN);
proto_tree_add_item(nsh_tree, hf_nsh_length, tvb, offset, 2, ENC_BIG_ENDIAN);
md_type = tvb_get_guint8(tvb, offset + 2);
proto_tree_add_item(nsh_tree, hf_nsh_md_type, tvb, offset + 2, 1, ENC_BIG_ENDIAN);
nsh_next_proto = tvb_get_guint8(tvb, offset + 3);
proto_tree_add_item(nsh_tree, hf_nsh_next_proto, tvb, offset + 3, 1, ENC_BIG_ENDIAN);
/*NSH Service Path Header */
offset = offset + 4;
proto_tree_add_item(nsh_tree, hf_nsh_service_pathID, tvb, offset, 3, ENC_BIG_ENDIAN);
proto_tree_add_item(nsh_tree, hf_nsh_service_index, tvb, offset + 3, 1, ENC_BIG_ENDIAN);
/* Decode Context Headers */
offset = offset + 4;
switch (md_type) {
case MD_TYPE_1:
dissect_nsh_md_type_1(tvb, nsh_tree, offset);
break;
case MD_TYPE_2:
/* MD Type 2 indicates ZERO or more Variable Length Context headers*/
if (nsh_bytes_len > 8)
dissect_nsh_md_type_2(tvb, nsh_tree, offset, nsh_bytes_len);
break;
}
/*Decode next protocol payload */
if (captured_length > (nsh_bytes_len)) {
next_tvb = tvb_new_subset_remaining(tvb, nsh_bytes_len);
switch (nsh_next_proto) {
case NSH_IPV4:
call_dissector(dissector_ip, next_tvb, pinfo, tree);
break;
case NSH_IPV6:
call_dissector(dissector_ipv6, next_tvb, pinfo, tree);
break;
case NSH_ETHERNET:
call_dissector(dissector_eth, next_tvb, pinfo, tree);
break;
}
}
}
return tvb_captured_length(tvb);
}
void
proto_register_nsh(void)
{
static hf_register_info nsh_info[] = {
/* Network Service Header fields */
{ &hf_nsh_version,
{ "Version", "nsh.version",
FT_UINT16, BASE_DEC_HEX, NULL, 0xC000,
NULL, HFILL }
},
{ &hf_nsh_oam,
{ "O Bit", "nsh.Obit",
FT_UINT16, BASE_DEC, NULL, 0x2000,
"OAM Bit", HFILL }
},
{ &hf_nsh_critical_metadata,
{ "C Bit", "nsh.CBit",
FT_UINT16, BASE_DEC, NULL, 0x1000,
"Critical Metadata Bit", HFILL }
},
{ &hf_nsh_reservedbits,
{ "Reserved Bits", "nsh.reservedbits",
FT_UINT16, BASE_HEX, NULL, 0x0FC0,
"Reserved bits within NSH Base Header", HFILL }
},
{ &hf_nsh_length,
{ "Length", "nsh.length",
FT_UINT16, BASE_DEC_HEX, NULL, 0x003F,
"Total length, in 4-byte words, of NSH including Base, Service Path headers and optional variable TLVs", HFILL }
},
{ &hf_nsh_md_type,
{ "MD Type", "nsh.mdtype",
FT_UINT8, BASE_DEC_HEX, NULL, 0x00,
"Metadata Type defines the format of the metadata being carried", HFILL }
},
{ &hf_nsh_next_proto,
{ "Next Protocol", "nsh.nextproto",
FT_UINT8, BASE_DEC_HEX, VALS(nsh_next_protocols), 0x00,
"Protocol type of the original packet", HFILL }
},
{ &hf_nsh_service_pathID,
{ "SPI", "nsh.spi",
FT_UINT24, BASE_DEC_HEX, NULL, 0x00,
"Service Path Identifier", HFILL }
},
{ &hf_nsh_service_index,
{ "SI", "nsh.si",
FT_UINT8, BASE_DEC_HEX, NULL, 0x00,
"Service Index", HFILL }
},
{ &hf_nsh_context_header,
{ "Context Header", "nsh.contextheader",
FT_BYTES, BASE_NONE, NULL, 0x00,
"Manadatory Context Header", HFILL }
},
{ &hf_nsh_metadata_class,
{ "TLV Class", "nsh.metadataclass",
FT_UINT16, BASE_DEC_HEX, NULL, 0x00,
"TLV class describes the scope of the metadata type field", HFILL }
},
{ &hf_nsh_metadata_type,
{ "Type", "nsh.metadatatype",
FT_UINT8, BASE_DEC_HEX, NULL, 0x00,
"Type of metadata", HFILL }
},
{ &hf_nsh_metadata_reservedbits,
{ "Reserved Bits", "nsh.metadatareservedbits",
FT_UINT8, BASE_HEX, NULL, 0xE0,
"Reserved Bits within Variable Length Metadata header", HFILL }
},
{ &hf_nsh_metadata_length,
{ "Length", "nsh.metadatalen",
FT_UINT8, BASE_HEX, NULL, 0x1F,
"Length of the variable metadata in 4-byte words", HFILL }
},
{ &hf_nsh_metadata,
{ "Variable Metadata", "nsh.metadata",
FT_BYTES, BASE_NONE, NULL, 0x00,
"Variable length metadata", HFILL }
},
};
static gint *ett[] = {
&ett_nsh,
};
proto_nsh = proto_register_protocol("Network Service Header",
"NSH", "nsh");
proto_register_field_array(proto_nsh, nsh_info, array_length(nsh_info));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_nsh(void)
{
dissector_handle_t nsh_handle;
nsh_handle = create_dissector_handle(dissect_nsh, proto_nsh);
dissector_add_uint("gre.proto", ETHERTYPE_NSH, nsh_handle);
dissector_add_uint("vxlan.next_proto", VXLAN_NSH, nsh_handle);
dissector_ip = find_dissector_add_dependency("ip", proto_nsh);
dissector_ipv6 = find_dissector_add_dependency("ipv6", proto_nsh);
dissector_eth = find_dissector_add_dependency("eth_maybefcs", proto_nsh);
}
/*
* 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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