/* packet-geneve.c

 * Routines for Geneve - Generic Network Virtualization Encapsulation

 * https://tools.ietf.org/html/draft-ietf-nvo3-geneve

 *

 * Copyright (c) 2024 cPacket Networks, Inc. All Rights Reserved.

 * Author: Martin Greenberg <mgreenberg@cpacket.com>

 *

 * Copyright (c) 2014 VMware, Inc. All Rights Reserved.

 * Author: Jesse Gross <jesse@nicira.com>

 *

 * Copyright 2021, Atul Sharma <asharm37@ncsu.edu>

 *

 * 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>

#include <epan/expert.h>

#include <epan/value_string.h>

#include <epan/tfs.h>

#include <epan/unit_strings.h>

#define UDP_PORT_GENEVE  6081

#define GENEVE_VER 0

#define VER_SHIFT 6

#define HDR_OPTS_LEN_MASK 0x3F

#define FLAG_OAM (1 << 7)

#define OPT_TYPE_CRITICAL (1 << 7)

#define OPT_FLAGS_SHIFT 5

#define OPT_LEN_MASK 0x1F

static const range_string class_id_names[] = {

    { 0, 0xFF, "Standard" },

    { 0x0100, 0x0100, "Linux" },

    { 0x0101, 0x0101, "Open vSwitch" },

    { 0x0102, 0x0102, "Open Virtual Networking (OVN)" },

    { 0x0103, 0x0103, "In-band Network Telemetry (INT)" },

    { 0x0104, 0x0104, "VMware" },

    { 0x0105, 0x0105, "Amazon.com, Inc."},

    { 0x0106, 0x0106, "Cisco Systems, Inc." },

    { 0x0107, 0x0107, "Oracle Corporation" },

    { 0x0108, 0x0110, "Amazon.com, Inc." },

    { 0x0111, 0x0118, "IBM" },

    { 0x0119, 0x0128, "Ericsson" },

    { 0x0129, 0x0129, "Oxide Computer Company" },

    { 0x0130, 0x0131, "Cisco Systems, Inc." },

    { 0x0132, 0x0135, "Google LLC" },

    { 0x0136, 0x0136, "InfoQuick Global Connection Tech Ltd." },

    { 0x0137, 0x0163, "Unssigned" },

    { 0x0164, 0x0164, "cPacket Networks, Inc." },

    { 0x0165, 0xFEFF, "Unassigned" },

    { 0xFFF0, 0xFFFF, "Experimental" },

    { 0, 0, NULL }

};

#define GENEVE_GCP_VNID     0x013201

#define GENEVE_GCP_ENDPOINT 0x013202

#define GENEVE_GCP_PROFILE  0x013203

#define GENEVE_CPACKET_METADATA  0x016400

static const val64_string option_names[] = {

  { GENEVE_GCP_VNID,     "GCP Virtual Network ID" },

  { GENEVE_GCP_ENDPOINT, "GCP Endpoint ID" },

  { GENEVE_GCP_PROFILE,  "GCP Profile ID" },

  { GENEVE_CPACKET_METADATA,  "cPacket Meta-data" },

  { 0, NULL }

};

void proto_register_geneve(void);

void proto_reg_handoff_geneve(void);

static dissector_handle_t geneve_handle;

static int proto_geneve;

static int hf_geneve_version;

static int hf_geneve_flags;

static int hf_geneve_flag_oam;

static int hf_geneve_flag_critical;

static int hf_geneve_flag_reserved;

static int hf_geneve_proto_type;

static int hf_geneve_vni;

static int hf_geneve_reserved;

static int hf_geneve_options;

static int hf_geneve_option_class;

static int hf_geneve_option_type;

static int hf_geneve_option_type_critical;

static int hf_geneve_option_flags;

static int hf_geneve_option_flags_reserved;

static int hf_geneve_option_length;

static int hf_geneve_option;

static int hf_geneve_opt_gcp_vnid;

static int hf_geneve_opt_gcp_reserved;

static int hf_geneve_opt_gcp_direction;

static int hf_geneve_opt_gcp_endpoint;

static int hf_geneve_opt_gcp_profile;

static int hf_geneve_opt_cpkt_seqnum;

static int hf_geneve_opt_cpkt_origlen;

static int hf_geneve_opt_cpkt_reserved;

static int hf_geneve_opt_cpkt_timestamp;

static int hf_geneve_opt_cpkt_ts_sec;

static int hf_geneve_opt_cpkt_ts_nsec;

static int hf_geneve_opt_cpkt_ts_fracns;

static int hf_geneve_opt_cpkt_version;

static int hf_geneve_opt_cpkt_devid;

static int hf_geneve_opt_cpkt_portid;

static int hf_geneve_opt_unknown_data;

static int ett_geneve;

static int ett_geneve_flags;

static int ett_geneve_opt_flags;

static int ett_geneve_options;

static int ett_geneve_opt_data;

static expert_field ei_geneve_ver_unknown;

static expert_field ei_geneve_opt_len_invalid;

static dissector_table_t ethertype_dissector_table;

static const struct true_false_string tfs_geneve_gcp_direction = {

  "Egress",

  "Ingress"

};

static const char *

format_option_name(wmem_allocator_t *scope, uint16_t opt_class, uint8_t opt_type)

{

    const char *name;

    name = wmem_strdup_printf(scope,

                              "%s, Class: %s (0x%04x) Type: 0x%02x",

                              val64_to_str_const(((uint64_t)opt_class << 8) | opt_type,

                                                 option_names, "Unknown"),

                              rval_to_str_const(opt_class, class_id_names, "Unknown"),

                              opt_class, opt_type);

    return name;

}

static void

dissect_option(wmem_allocator_t *scope, tvbuff_t *tvb, proto_tree *opts_tree, int offset,

               uint16_t opt_class, uint8_t opt_type, int len)

{

    proto_item *opt_item, *type_item, *hidden_item, *flag_item;

    proto_tree *opt_tree, *flag_tree;

    const char *critical;

    uint8_t flags;

    critical = opt_type & OPT_TYPE_CRITICAL ? "Critical" : "Non-critical";

    opt_item = proto_tree_add_item(opts_tree, hf_geneve_option,

                                   tvb, offset, len, ENC_NA);

    proto_item_set_text(opt_item, "%s (%s)",

                        format_option_name(scope, opt_class, opt_type),

                        critical);

    opt_tree = proto_item_add_subtree(opt_item, ett_geneve_opt_data);

    proto_tree_add_item(opt_tree, hf_geneve_option_class, tvb,

                        offset, 2, ENC_BIG_ENDIAN);

    offset += 2;

    type_item = proto_tree_add_item(opt_tree, hf_geneve_option_type, tvb,

                                    offset, 1, ENC_BIG_ENDIAN);

    proto_item_append_text(type_item, " (%s)", critical);

    hidden_item = proto_tree_add_item(opt_tree, hf_geneve_option_type_critical,

                                      tvb, offset, 1, ENC_BIG_ENDIAN);

    proto_item_set_hidden(hidden_item);

    offset += 1;

    flags = tvb_get_uint8(tvb, offset) >> OPT_FLAGS_SHIFT;

    flag_item = proto_tree_add_uint(opt_tree, hf_geneve_option_flags, tvb,

                                    offset, 1, flags);

    flag_tree = proto_item_add_subtree(flag_item, ett_geneve_opt_flags);

    proto_tree_add_item(flag_tree, hf_geneve_option_flags_reserved, tvb,

                        offset, 1, ENC_BIG_ENDIAN);

    if (flags) {

        proto_item_append_text(flag_item, " (RSVD)");

    } else {

        proto_item_set_hidden(flag_item);

    }

    proto_tree_add_uint(opt_tree, hf_geneve_option_length, tvb, offset, 1, len);

    offset += 1;

    switch (((uint64_t)opt_class << 8) | opt_type) {

        case GENEVE_GCP_VNID:

            proto_tree_add_bits_item(opt_tree, hf_geneve_opt_gcp_vnid, tvb, offset * 8,

                                     28, ENC_BIG_ENDIAN);

            proto_tree_add_item(opt_tree, hf_geneve_opt_gcp_direction, tvb, offset,

                                4, ENC_NA);

            proto_tree_add_item(opt_tree, hf_geneve_opt_gcp_reserved, tvb, offset,

                                4, ENC_NA);

            break;

        case GENEVE_GCP_ENDPOINT:

            proto_tree_add_item(opt_tree, hf_geneve_opt_gcp_endpoint, tvb, offset,

                                len - 4, ENC_NA);

            break;

        case GENEVE_GCP_PROFILE:

            proto_tree_add_item(opt_tree, hf_geneve_opt_gcp_profile, tvb, offset,

                                len - 4, ENC_BIG_ENDIAN);

            break;

        case GENEVE_CPACKET_METADATA:

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_seqnum, tvb, offset,

                                4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_origlen, tvb, offset,

                                2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_reserved, tvb, offset,

                                1, ENC_BIG_ENDIAN);

            offset += 1;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_version, tvb, offset,

                                1, ENC_BIG_ENDIAN);

            offset += 1;

            // PTPv2 timestamp has more resolution than NStime supports/displays,

            // but parse appropriate subsection of into NStime for user convenience

            proto_tree_add_time_item(opt_tree, hf_geneve_opt_cpkt_timestamp, tvb, offset+2, 8,

                                     ENC_TIME_SECS_NSECS, NULL, NULL, NULL);

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_ts_sec, tvb, offset,

                                6, ENC_BIG_ENDIAN);

            offset += 6;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_ts_nsec, tvb, offset,

                                4, ENC_BIG_ENDIAN);

            offset += 4;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_ts_fracns, tvb, offset,

                                2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_devid, tvb, offset,

                                2, ENC_BIG_ENDIAN);

            offset += 2;

            proto_tree_add_item(opt_tree, hf_geneve_opt_cpkt_portid, tvb, offset,

                                2, ENC_BIG_ENDIAN);

            break;

        default:

            proto_tree_add_item(opt_tree, hf_geneve_opt_unknown_data, tvb, offset,

                                len - 4, ENC_NA);

            break;

    }

}

static void

dissect_geneve_options(tvbuff_t *tvb, packet_info *pinfo,

                       proto_tree *geneve_tree, int offset, int len)

{

    proto_item *opts_item;

    proto_tree *opts_tree;

    uint16_t opt_class;

    uint8_t opt_type;

    uint8_t opt_len;

    opts_item = proto_tree_add_item(geneve_tree, hf_geneve_options, tvb,

                                    offset, len, ENC_NA);

    proto_item_set_text(opts_item, "Options: (%u bytes)", len);

    opts_tree = proto_item_add_subtree(opts_item, ett_geneve_options);

    while (len > 0) {

        opt_class = tvb_get_ntohs(tvb, offset);

        opt_type = tvb_get_uint8(tvb, offset + 2);

        opt_len = 4 + ((tvb_get_uint8(tvb, offset + 3) & OPT_LEN_MASK) * 4);

        if (opt_len > len) {

            proto_tree_add_expert_format(opts_tree, pinfo,

                                         &ei_geneve_opt_len_invalid, tvb,

                                         offset + 3, 1,

                                         "%s (length of %u is past end of options)",

                                         format_option_name(pinfo->pool, opt_class, opt_type),

                                         opt_len);

            return;

        }

        dissect_option(pinfo->pool, tvb, opts_tree, offset, opt_class, opt_type, opt_len);

        offset += opt_len;

        len -= opt_len;

    };

}

static int

dissect_geneve(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)

{

    proto_item *ti, *rsvd_item;

    proto_tree *geneve_tree;

    tvbuff_t *next_tvb;

    int offset = 0;

    uint8_t ver_opt;

    uint8_t ver;

    uint8_t flags;

    uint16_t proto_type;

    int opts_len;

    static int * const flag_fields[] = {

        &hf_geneve_flag_oam,

        &hf_geneve_flag_critical,

        &hf_geneve_flag_reserved,

        NULL

    };

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "Geneve");

    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_geneve, tvb, offset, -1, ENC_NA);

    geneve_tree = proto_item_add_subtree(ti, ett_geneve);

    /* Version. */

    ver_opt = tvb_get_uint8(tvb, offset);

    ver = ver_opt >> VER_SHIFT;

    proto_tree_add_uint(geneve_tree, hf_geneve_version, tvb,

                        offset, 1, ver);

    if (ver != GENEVE_VER) {

        proto_tree_add_expert_format(geneve_tree, pinfo,

                                     &ei_geneve_ver_unknown, tvb, offset, 1,

                                     "Unknown version %u", ver);

        col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown Geneve version %u", ver);

    }

    /* Option length. */

    opts_len = (ver_opt & HDR_OPTS_LEN_MASK) * 4;

    proto_tree_add_uint(geneve_tree, hf_geneve_option_length, tvb,

                                     offset, 1, opts_len);

    offset += 1;

    /* Flags. */

    flags = tvb_get_uint8(tvb, offset);

    proto_tree_add_bitmask(geneve_tree, tvb, offset, hf_geneve_flags, ett_geneve_flags, flag_fields, ENC_BIG_ENDIAN);

    offset += 1;

    /* Protocol Type. */

    proto_tree_add_item(geneve_tree, hf_geneve_proto_type, tvb,

                        offset, 2, ENC_BIG_ENDIAN);

    proto_type = tvb_get_ntohs(tvb, offset);

    col_add_fstr(pinfo->cinfo, COL_INFO, "Encapsulated %s",

                 val_to_str(proto_type, etype_vals, "0x%04x (unknown)"));

    offset += 2;

    /* VNI. */

    proto_tree_add_item(geneve_tree, hf_geneve_vni, tvb, offset, 3,

                        ENC_BIG_ENDIAN);

    proto_item_append_text(ti, ", VNI: 0x%06x%s", tvb_get_ntoh24(tvb, offset),

                           flags & FLAG_OAM ? ", OAM" : "");

    offset += 3;

    /* Reserved. */

    rsvd_item = proto_tree_add_item(geneve_tree, hf_geneve_reserved, tvb,

                                    offset, 1, ENC_BIG_ENDIAN);

    if (!tvb_get_uint8(tvb, offset)) {

        proto_item_set_hidden(rsvd_item);

    }

    offset += 1;

    /* Options. */

    if (tree && opts_len) {

        dissect_geneve_options(tvb, pinfo, geneve_tree, offset, opts_len);

    }

    offset += opts_len;

    proto_item_set_len(ti, offset);

    next_tvb = tvb_new_subset_remaining(tvb, offset);

    if (!dissector_try_uint(ethertype_dissector_table, proto_type, next_tvb, pinfo, tree))

        call_data_dissector(next_tvb, pinfo, tree);

    return tvb_captured_length(tvb);

}

/* Register Geneve with Wireshark */

void

proto_register_geneve(void)

{

    static hf_register_info hf[] = {

        { &hf_geneve_version,

          { "Version", "geneve.version",

            FT_UINT8, BASE_DEC, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_flags,

          { "Flags", "geneve.flags",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_flag_oam,

          { "Operations, Administration and Management Frame", "geneve.flags.oam",

            FT_BOOLEAN, 8, NULL, 0x80,

            NULL, HFILL }

        },

        { &hf_geneve_flag_critical,

          { "Critical Options Present", "geneve.flags.critical",

            FT_BOOLEAN, 8, NULL, 0x40,

            NULL, HFILL }

        },

        { &hf_geneve_flag_reserved,

          { "Reserved", "geneve.flags.reserved",

            FT_BOOLEAN, 8, NULL, 0x3F,

            NULL, HFILL }

        },

        { &hf_geneve_proto_type,

          { "Protocol Type", "geneve.proto_type",

            FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,

            NULL, HFILL }

        },

        { &hf_geneve_vni,

          { "Virtual Network Identifier (VNI)", "geneve.vni",

            FT_UINT24, BASE_HEX_DEC, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_geneve_reserved,

          { "Reserved", "geneve.reserved",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_options,

          { "Geneve Options", "geneve.options",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_option_class,

          { "Class", "geneve.option.class",

            FT_UINT16, BASE_HEX | BASE_RANGE_STRING, RVALS(class_id_names), 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_option_type,

          { "Type", "geneve.option.type",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_option_type_critical,

          { "Critical Option", "geneve.option.type.critical",

            FT_BOOLEAN, 8, NULL, 0x80,

            NULL, HFILL }

        },

        { &hf_geneve_option_flags,

          { "Flags", "geneve.option.flags",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_option_flags_reserved,

          { "Reserved", "geneve.option.flags.reserved",

            FT_BOOLEAN, 8, NULL, 0xE0,

            NULL, HFILL }

        },

        { &hf_geneve_option_length,

          { "Length", "geneve.option.length",

            FT_UINT8, BASE_DEC|BASE_UNIT_STRING, UNS(&units_byte_bytes), 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_option,

          { "Option", "geneve.option",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_opt_gcp_vnid,

          { "GCP Virtual Network ID", "geneve.option.gcp.vnid",

            FT_UINT32, BASE_DEC, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_opt_gcp_reserved,

          { "GCP Reserved bits", "geneve.option.gcp.reserved",

            FT_BOOLEAN, 32, NULL, 0x0000000E,

            NULL, HFILL }

        },

        { &hf_geneve_opt_gcp_direction,

          { "GCP Traffic Direction", "geneve.option.gcp.direction",

            FT_BOOLEAN, 32, TFS(&tfs_geneve_gcp_direction), 0x00000001,

            NULL, HFILL }

        },

        { &hf_geneve_opt_gcp_endpoint,

          { "GCP Endpoint ID", "geneve.option.gcp.endpoint",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_opt_gcp_profile,

          { "GCP Profile ID", "geneve.option.gcp.profile",

            FT_UINT64, BASE_DEC, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_seqnum,

         { "cPacket Packet ID", "geneve.option.cPacket.packetid",

           FT_UINT32, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_origlen,

         { "cPacket Original length", "geneve.option.cPacket.orig_len",

           FT_UINT16, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_reserved,

         { "cPacket Reserved", "geneve.option.cPacket.reserved",

           FT_UINT8, BASE_HEX, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_version,

         { "cPacket Metadata version", "geneve.option.cPacket.version",

           FT_UINT8, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_timestamp,

         { "cPacket Timestamp", "geneve.option.cPacket.timestamp",

           FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_ts_sec,

         { "cPacket Timestamp (s)", "geneve.option.cPacket.ts_sec",

           FT_UINT48, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_ts_nsec,

         { "cPacket Timestamp (ns)", "geneve.option.cPacket.ts_nsec",

           FT_UINT32, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_ts_fracns,

         { "cPacket Timestamp (frac. ns)", "geneve.option.cPacket.ts_fracns",

           FT_UINT16, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_devid,

         { "cPacket Device ID", "geneve.option.cPacket.device_id",

           FT_UINT16, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_cpkt_portid,

         { "cPacket Port ID", "geneve.option.cPacket.port_id",

           FT_UINT16, BASE_DEC, NULL, 0x00,

           NULL, HFILL }

        },

        { &hf_geneve_opt_unknown_data,

          { "Unknown Option Data", "geneve.option.unknown.data",

            FT_BYTES, BASE_NONE, NULL, 0x00,

            NULL, HFILL }

        },

    };

    static int *ett[] = {

        &ett_geneve,

        &ett_geneve_flags,

        &ett_geneve_options,

        &ett_geneve_opt_flags,

        &ett_geneve_opt_data,

    };

    static ei_register_info ei[] = {

       { &ei_geneve_ver_unknown, { "geneve.version.unknown",

         PI_PROTOCOL, PI_WARN, "Unknown version", EXPFILL }},

       { &ei_geneve_opt_len_invalid, { "geneve.option.length.invalid",

         PI_PROTOCOL, PI_WARN, "Invalid length for option", EXPFILL }},

    };

    expert_module_t *expert_geneve;

    /* Register the protocol name and description */

    proto_geneve = proto_register_protocol("Generic Network Virtualization Encapsulation",

                                          "Geneve", "geneve");

    proto_register_field_array(proto_geneve, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    expert_geneve = expert_register_protocol(proto_geneve);

    expert_register_field_array(expert_geneve, ei, array_length(ei));

    geneve_handle = register_dissector("geneve", dissect_geneve, proto_geneve);

}

void

proto_reg_handoff_geneve(void)

{

    dissector_add_uint_with_preference("udp.port", UDP_PORT_GENEVE, geneve_handle);

    ethertype_dissector_table = find_dissector_table("ethertype");

}

/*

 * 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:

 */