/* packet-vxlan.c

 *

 * Routines for Virtual eXtensible Local Area Network (VXLAN) packet dissection

 * RFC 7348 plus draft-smith-vxlan-group-policy-01

 *

 * (c) Copyright 2016, Sumit Kumar Jha <sjha3@ncsu.edu>

 * Support for VXLAN GPE (https://datatracker.ietf.org/doc/html/draft-ietf-nvo3-vxlan-gpe-02)

 *

 * 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/tfs.h>

#include "packet-vxlan.h"

#define UDP_PORT_VXLAN  "4789,8472" /* The IANA assigned port is 4789, but Linux default is 8472 for compatibility with early adopters */

#define UDP_PORT_VXLAN_GPE  4790

void proto_register_vxlan(void);

void proto_reg_handoff_vxlan(void);

static dissector_handle_t vxlan_handle;

static dissector_handle_t vxlan_gpe_handle;

static int proto_vxlan;

static int proto_vxlan_gpe;

static int hf_vxlan_flags;

static int hf_vxlan_gpe_flags;

static int hf_vxlan_flags_reserved;

static int hf_vxlan_reserved_8;

static int hf_vxlan_flag_a;

static int hf_vxlan_flag_d;

static int hf_vxlan_flag_i;

static int hf_vxlan_flag_g;

static int hf_vxlan_gbp;

static int hf_vxlan_vni;

static int hf_vxlan_gpe_flag_i;

static int hf_vxlan_gpe_flag_p;

static int hf_vxlan_gpe_flag_o;

static int hf_vxlan_gpe_flag_ver;

static int hf_vxlan_gpe_flag_reserved;

static int hf_vxlan_gpe_reserved_16;

static int hf_vxlan_next_proto;

static int ett_vxlan;

static int ett_vxlan_flags;

static int * const flags_fields[] = {

        &hf_vxlan_flag_g,

        &hf_vxlan_flag_i,

        &hf_vxlan_flag_d,

        &hf_vxlan_flag_a,

        &hf_vxlan_flags_reserved,

        NULL

    };

static int * const gpe_flags_fields[] = {

        &hf_vxlan_gpe_flag_ver,

        &hf_vxlan_gpe_flag_i,

        &hf_vxlan_gpe_flag_p,

        &hf_vxlan_gpe_flag_o,

        &hf_vxlan_gpe_flag_reserved,

        NULL

   };

static const value_string vxlan_next_protocols[] = {

        { VXLAN_IPV4, "IPv4" },

        { VXLAN_IPV6, "IPv6" },

        { VXLAN_ETHERNET, "Ethernet" },

        { VXLAN_NSH, "Network Service Header" },

        { VXLAN_MPLS, "MPLS"},

        { 0, NULL }

 };

static dissector_handle_t eth_handle;

static dissector_table_t vxlan_dissector_table;

static int

dissect_vxlan_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int is_gpe)

{

    proto_tree *vxlan_tree;

    proto_item *ti;

    tvbuff_t *next_tvb;

    int offset = 0;

    uint32_t vxlan_next_proto;

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

    col_clear(pinfo->cinfo, COL_INFO);

    ti = proto_tree_add_item(tree, proto_vxlan, tvb, offset, 8, ENC_NA);

    vxlan_tree = proto_item_add_subtree(ti, ett_vxlan);

    if(is_gpe) {

        proto_tree_add_bitmask(vxlan_tree, tvb, offset, hf_vxlan_gpe_flags, ett_vxlan_flags, gpe_flags_fields, ENC_BIG_ENDIAN);

        offset += 1;

        proto_tree_add_item(vxlan_tree, hf_vxlan_gpe_reserved_16, tvb, offset, 2, ENC_BIG_ENDIAN);

        offset += 2;

        proto_tree_add_item_ret_uint(vxlan_tree, hf_vxlan_next_proto, tvb, offset, 1, ENC_BIG_ENDIAN, &vxlan_next_proto);

        offset += 1;

    } else {

        proto_tree_add_bitmask(vxlan_tree, tvb, offset, hf_vxlan_flags, ett_vxlan_flags, flags_fields, ENC_BIG_ENDIAN);

        offset += 2;

        proto_tree_add_item(vxlan_tree, hf_vxlan_gbp, tvb, offset, 2, ENC_BIG_ENDIAN);

        offset += 2;

    }

    proto_tree_add_item(vxlan_tree, hf_vxlan_vni, tvb, offset, 3, ENC_BIG_ENDIAN);

    offset += 3;

    proto_tree_add_item(vxlan_tree, hf_vxlan_reserved_8, tvb, offset, 1, ENC_BIG_ENDIAN);

    offset += 1;

    next_tvb = tvb_new_subset_remaining(tvb, offset);

    if(is_gpe){

        if(!dissector_try_uint(vxlan_dissector_table, vxlan_next_proto, next_tvb, pinfo, tree)) {

            call_data_dissector(next_tvb, pinfo, tree);

        }

    } else {

        call_dissector(eth_handle, next_tvb, pinfo, tree);

    }

    return tvb_captured_length(tvb);

}

static int

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

{

    return dissect_vxlan_common(tvb, pinfo, tree, true);

}

static int

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

{

    return dissect_vxlan_common(tvb, pinfo, tree, false);

}

/* Register VxLAN with Wireshark */

void

proto_register_vxlan(void)

{

    static hf_register_info hf[] = {

        { &hf_vxlan_flags,

          { "Flags", "vxlan.flags",

            FT_UINT16, BASE_HEX, NULL, 0x00,

            NULL, HFILL

          },

        },

        { &hf_vxlan_gpe_flags,

          { "Flags", "vxlan.flags",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL

          },

        },

        { &hf_vxlan_flags_reserved,

          { "Reserved(R)", "vxlan.flags_reserved",

            FT_UINT16, BASE_HEX, NULL, 0x77b7,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gpe_flag_reserved,

          { "Reserved(R)", "vxlan.flags_reserved",

            FT_UINT8, BASE_DEC, NULL, 0xC2,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_flag_g,

          { "GBP Extension", "vxlan.flag_g",

            FT_BOOLEAN, 16, TFS(&tfs_defined_not_defined), 0x8000,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_flag_i,

          { "VXLAN Network ID (VNI)", "vxlan.flag_i",

            FT_BOOLEAN, 16, NULL, 0x0800,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_flag_d,

          { "Don't Learn", "vxlan.flag_d",

            FT_BOOLEAN, 16, NULL, 0x0040,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_flag_a,

          { "Policy Applied", "vxlan.flag_a",

            FT_BOOLEAN, 16, NULL, 0x0008,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gpe_flag_ver,

          { "Version", "vxlan.ver",

            FT_UINT8, BASE_DEC, NULL, 0x30,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gpe_flag_i,

          { "Instance", "vxlan.i_bit",

            FT_UINT8, BASE_DEC, NULL, 0x08,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gpe_flag_p,

          { "Next Protocol Bit", "vxlan.p_bit",

            FT_UINT8, BASE_DEC, NULL, 0x04,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gpe_flag_o,

          { "OAM bit", "vxlan.o_bit",

            FT_UINT8, BASE_DEC, NULL, 0x01,

            NULL, HFILL,

          },

        },

        { &hf_vxlan_gbp,

          { "Group Policy ID", "vxlan.gbp",

            FT_UINT16, BASE_DEC, NULL, 0x0,

            NULL, HFILL

          },

        },

        { &hf_vxlan_vni,

          { "VXLAN Network Identifier (VNI)", "vxlan.vni",

            FT_UINT24, BASE_DEC, NULL, 0x0,

            NULL, HFILL

          },

        },

        { &hf_vxlan_reserved_8,

          { "Reserved", "vxlan.reserved8",

            FT_UINT8, BASE_DEC, NULL, 0x0,

            NULL, HFILL

          },

        },

        { &hf_vxlan_gpe_reserved_16,

          { "Reserved", "vxlan.reserved_16",

            FT_UINT16, BASE_DEC, NULL, 0x0,

            NULL, HFILL

          },

        },

        { &hf_vxlan_next_proto,

          { "Next Protocol", "vxlan.next_proto",

            FT_UINT8, BASE_DEC, VALS(vxlan_next_protocols), 0x0,

            NULL, HFILL

          },

        },

    };

    /* Setup protocol subtree array */

    static int *ett[] = {

        &ett_vxlan,

        &ett_vxlan_flags,

    };

    /* Register the protocol name and description */

    proto_vxlan = proto_register_protocol("Virtual eXtensible Local Area Network", "VXLAN", "vxlan");

    /* Protocol registered just for Decode As */

    proto_vxlan_gpe = proto_register_protocol_in_name_only("Virtual eXtensible Local Area Network (GPE)", "VXLAN (GPE)", "vxlan_gpe", proto_vxlan, FT_PROTOCOL);

    /* Required function calls to register the header fields and subtrees used */

    proto_register_field_array(proto_vxlan, hf, array_length(hf));

    proto_register_subtree_array(ett, array_length(ett));

    vxlan_dissector_table = register_dissector_table("vxlan.next_proto", "VXLAN Next Protocol", proto_vxlan, FT_UINT8, BASE_DEC);

    /* Register dissector handles */

    vxlan_handle = register_dissector("vxlan", dissect_vxlan, proto_vxlan);

    vxlan_gpe_handle = register_dissector("vxlan_gpe", dissect_vxlan_gpe, proto_vxlan_gpe);

}

void

proto_reg_handoff_vxlan(void)

{

    /*

     * RFC 7348 Figures 1 and 2, in the Payload section, say

     *

     * "(Note that the original Ethernet Frame's FCS is not included)"

     *

     * meaning that the inner Ethernet frame does *not* include an

     * FCS.

     */

    eth_handle = find_dissector_add_dependency("eth_withoutfcs", proto_vxlan);

    dissector_add_uint_range_with_preference("udp.port", UDP_PORT_VXLAN, vxlan_handle);

    dissector_add_uint_with_preference("udp.port", UDP_PORT_VXLAN_GPE, vxlan_gpe_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:

 */