/* packet-nsh.c * Routines for Network Service Header * draft-ietf-sfc-nsh-01 * Author: Chidambaram Arunachalam * Copyright 2016, ciscoSystems Inc. * * (c) Copyright 2016, Sumit Kumar Jha * Support for VXLAN GPE encapsulation * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * 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 #include #include #include "packet-nsh.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); static const value_string nsh_next_protocols[] = { { NSH_IPV4, "IPv4" }, { NSH_IPV6, "IPv6" }, { NSH_ETHERNET, "Ethernet" }, { NSH_NSH, "NSH" }, { NSH_MPLS, "MPLS" }, { NSH_EXPERIMENT_1, "Experiment 1" }, { NSH_EXPERIMENT_2, "Experiment 2" }, { 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 expert_field ei_nsh_length_invalid = EI_INIT; static gint ett_nsh = -1; static dissector_table_t subdissector_table; /* *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; guint32 nsh_bytes_len; int nsh_next_proto = -1; proto_item *length_pi; tvbuff_t *next_tvb; col_set_str(pinfo->cinfo, COL_PROTOCOL, "NSH"); col_set_str(pinfo->cinfo, COL_INFO, "Network Service Header"); proto_item *ti; proto_tree *nsh_tree; ti = proto_tree_add_item(tree, proto_nsh, tvb, offset, 2, 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); length_pi = proto_tree_add_item_ret_uint(nsh_tree, hf_nsh_length, tvb, offset, 2, ENC_BIG_ENDIAN, &nsh_bytes_len); nsh_bytes_len *= 4; proto_item_set_len(ti, nsh_bytes_len); 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: /* The Length MUST be of value 0x6 for MD Type equal to 0x1 */ if (nsh_bytes_len != 4 * 6) { expert_add_info_format(pinfo, length_pi, &ei_nsh_length_invalid, "Length MUST be of value 0x6 for MD Type equal to 0x1"); nsh_bytes_len = 4 * 6; } dissect_nsh_md_type_1(tvb, nsh_tree, offset); break; case MD_TYPE_2: /* The Length MUST be of value 0x2 or greater for MD Type equal to 0x2 */ if (nsh_bytes_len < 4 * 2) { expert_add_info_format(pinfo, length_pi, &ei_nsh_length_invalid, "Length MUST be of value 0x2 or greater for MD Type equal to 0x2"); nsh_bytes_len = 4 * 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; default: /* * Unknown type, but assume presence of at least the NSH * Base Header (32 bits, 4 bytes). */ if (nsh_bytes_len < 4) { expert_add_info_format(pinfo, length_pi, &ei_nsh_length_invalid, "Length must be at least 0x1 for NSH Base Header"); nsh_bytes_len = 4; } break; } /*Decode next protocol payload */ if (tvb_captured_length_remaining(tvb, nsh_bytes_len) > 0) { next_tvb = tvb_new_subset_remaining(tvb, nsh_bytes_len); if (!dissector_try_uint(subdissector_table, nsh_next_proto, next_tvb, pinfo, tree)) { call_data_dissector(next_tvb, pinfo, tree); } } return tvb_captured_length(tvb); } void proto_register_nsh(void) { expert_module_t *expert_nsh; 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, }; static ei_register_info ei[] = { { &ei_nsh_length_invalid, { "nsh.length.invalid", PI_PROTOCOL, PI_WARN, "Invalid total length", EXPFILL }}, }; 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)); expert_nsh = expert_register_protocol(proto_nsh); expert_register_field_array(expert_nsh, ei, array_length(ei)); subdissector_table = register_dissector_table("nsh.next_proto", "NSH Next Protocol", proto_nsh, FT_UINT32, BASE_DEC); } void proto_reg_handoff_nsh(void) { static dissector_handle_t nsh_handle; nsh_handle = create_dissector_handle(dissect_nsh, proto_nsh); dissector_add_uint("ethertype", ETHERTYPE_NSH, nsh_handle); dissector_add_uint("gre.proto", ETHERTYPE_NSH, nsh_handle); dissector_add_uint("vxlan.next_proto", VXLAN_NSH, nsh_handle); dissector_add_uint("nsh.next_proto", NSH_NSH, nsh_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: */