/* packet-bfd.c

 * Routines for Bidirectional Forwarding Detection (BFD) message dissection

 * RFCs

 *   5880: Bidirectional Forwarding Detection (BFD)

 *   5881: Bidirectional Forwarding Detection (BFD) for IPv4 and IPv6 (Single Hop)

 *   5882: Generic Application of Bidirectional Forwarding Detection (BFD)

 *   5883: Bidirectional Forwarding Detection (BFD) for Multihop Paths

 *   5884: Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)

 *   5885: Bidirectional Forwarding Detection (BFD) for the Pseudowire Virtual Circuit Connectivity Verification (VCCV)

 *   7130: Bidirectional Forwarding Detection (BFD) on Link Aggregation Group (LAG) Interfaces

 *   7881: Seamless Bidirectional Forwarding Detection (S-BFD) for IPv4, IPv6, and MPLS

 * (and https://tools.ietf.org/html/draft-ietf-bfd-base-01 for version 0)

 *

 * Copyright 2003, Hannes Gredler <hannes@juniper.net>

 * Copyright 2006, Balint Reczey <Balint.Reczey@ericsson.com>

 * Copyright 2007, Todd J Martin <todd.martin@acm.org>

 *

 * Copyright 2011, Jaihari Kalijanakiraman <jaiharik@ipinfusion.com>

 *                 Krishnamurthy Mayya <krishnamurthy.mayya@ipinfusion.com>

 *                 Nikitha Malgi       <malgi.nikitha@ipinfusion.com>

 *                  - support for MPLS-TP BFD Proactive CV Message Format as per RFC 6428

 *                  - includes decoding support for Section MEP-ID, LSP MEP-ID, PW MEP-ID

 *

 * 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/expert.h>

#include <epan/tfs.h>

#include <epan/unit_strings.h>

#include "packet-bfd.h"

#include "packet-mpls.h"

void proto_register_bfd(void);

void proto_reg_handoff_bfd(void);

static dissector_handle_t bfd_control_handle;

static dissector_handle_t bfd_echo_handle;

/* 3784: BFD control, 3785: BFD echo, 4784: BFD multi hop control */

/* 6784: BFD on LAG, 7784: seamless BFD */

/* https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=bfd */

#define UDP_PORT_RANGE_BFD_CTRL  "3784,4784,6784,7784"

#define UDP_PORT_BFD_ECHO  3785

/* As per RFC 6428 : https://tools.ietf.org/html/rfc6428

   Section: 3.5 */

#define TLV_TYPE_MPLSTP_SECTION_MEP   0

#define TLV_TYPE_MPLSTP_LSP_MEP       1

#define TLV_TYPE_MPLSTP_PW_MEP        2

static const value_string mplstp_mep_tlv_type_values [] = {

    { TLV_TYPE_MPLSTP_SECTION_MEP, "Section MEP-ID" },

    { TLV_TYPE_MPLSTP_LSP_MEP,     "LSP MEP-ID" },

    { TLV_TYPE_MPLSTP_PW_MEP,      "PW MEP-ID" },

    { 0, NULL}

};

static const value_string bfd_control_v0_diag_values[] = {

    { 0, "No Diagnostic" },

    { 1, "Control Detection Time Expired" },

    { 2, "Echo Function Failed" },

    { 3, "Neighbor Signaled Session Down" },

    { 4, "Forwarding Plane Reset" },

    { 5, "Path Down" },

    { 6, "Concatenated Path Down" },

    { 7, "Administratively Down" },

    { 0, NULL }

};

static const value_string bfd_control_v1_diag_values[] = {

    { 0, "No Diagnostic" },

    { 1, "Control Detection Time Expired" },

    { 2, "Echo Function Failed" },

    { 3, "Neighbor Signaled Session Down" },

    { 4, "Forwarding Plane Reset" },

    { 5, "Path Down" },

    { 6, "Concatenated Path Down" },

    { 7, "Administratively Down" },

    { 8, "Reverse Concatenated Path Down" },

    { 9, "Mis-Connectivity Defect" },

    { 0, NULL }

};

static const value_string bfd_control_sta_values[] = {

    { 0, "AdminDown" },

    { 1, "Down" },

    { 2, "Init" },

    { 3, "Up" },

    { 0, NULL }

};

#define BFD_AUTH_SIMPLE    1

#define BFD_AUTH_MD5       2

#define BFD_AUTH_MET_MD5   3

#define BFD_AUTH_SHA1      4

#define BFD_AUTH_MET_SHA1  5

static const value_string bfd_control_auth_type_values[] = {

    { BFD_AUTH_SIMPLE      , "Simple Password" },

    { BFD_AUTH_MD5         , "Keyed MD5" },

    { BFD_AUTH_MET_MD5     , "Meticulous Keyed MD5" },

    { BFD_AUTH_SHA1        , "Keyed SHA1" },

    { BFD_AUTH_MET_SHA1    , "Meticulous Keyed SHA1" },

    { 0, NULL }

};

/* Per the standard, the simple password must by 1-16 bytes in length */

#define MAX_PASSWORD_LEN 16

/* Per the standard, the length of the MD5 authentication packets must be 24

 * bytes and the checksum is 16 bytes */

#define MD5_AUTH_LEN 24

#define MD5_CHECKSUM_LEN 16

/* Per the standard, the length of the SHA1 authentication packets must be 28

 * bytes and the checksum is 20 bytes */

#define SHA1_AUTH_LEN 28

#define SHA1_CHECKSUM_LEN 20

static int proto_bfd;

static int proto_bfd_echo;

static int hf_bfd_version;

static int hf_bfd_diag;

static int hf_bfd_sta;

static int hf_bfd_flags;

static int hf_bfd_flags_h;

static int hf_bfd_flags_p;

static int hf_bfd_flags_f;

static int hf_bfd_flags_c;

static int hf_bfd_flags_a;

static int hf_bfd_flags_d;

static int hf_bfd_flags_m;

static int hf_bfd_flags_d_v0;

static int hf_bfd_flags_p_v0;

static int hf_bfd_flags_f_v0;

static int hf_bfd_detect_time_multiplier;

static int hf_bfd_message_length;

static int hf_bfd_my_discriminator;

static int hf_bfd_your_discriminator;

static int hf_bfd_desired_min_tx_interval;

static int hf_bfd_required_min_rx_interval;

static int hf_bfd_required_min_echo_interval;

static int hf_bfd_checksum;

static int hf_bfd_auth_type;

static int hf_bfd_auth_len;

static int hf_bfd_auth_key;

static int hf_bfd_auth_password;

static int hf_bfd_auth_seq_num;

static int hf_bfd_echo;

static int ett_bfd;

static int ett_bfd_flags;

static int ett_bfd_auth;

static int ett_bfd_echo;

static expert_field ei_bfd_auth_len_invalid;

static expert_field ei_bfd_auth_no_data;

static int hf_mep_type;

static int hf_mep_len;

static int hf_mep_global_id;

static int hf_mep_node_id;

/* static int hf_mep_interface_no; */

static int hf_mep_tunnel_no;

static int hf_mep_lsp_no;

static int hf_mep_ac_id;

static int hf_mep_agi_type;

static int hf_mep_agi_len;

static int hf_mep_agi_val;

static int hf_section_interface_no;

/*

 * Control packet version 0, draft-katz-ward-bfd-01.txt

 *

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |Vers |  Diag   |H|D|P|F| Rsvd  |  Detect Mult  |    Length     |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                       My Discriminator                        |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                      Your Discriminator                       |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                    Desired Min TX Interval                    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                   Required Min RX Interval                    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                 Required Min Echo RX Interval                 |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 */

/*

 * Control packet version 1, RFC 5880

 *

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                       My Discriminator                        |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                      Your Discriminator                       |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                    Desired Min TX Interval                    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                   Required Min RX Interval                    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                 Required Min Echo RX Interval                 |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *

 *    An optional Authentication Section may be present:

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |   Auth Type   |   Auth Len    |    Authentication Data...     |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *

 *    There are 5 types of authentication defined:

 *      1 - Simple Password

 *      2 - Keyed MD5

 *      3 - Meticulous Keyed MD5

 *      4 - Keyed SHA1

 *      5 - Meticulous Keyed SHA1

 *

 *     The format for Simple Password authentication is:

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |  Password...  |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                              ...                              |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *

 *    The format for Keyed MD5 and Meticulous Keyed MD5 authentication is:

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                        Sequence Number                        |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                     Auth Key/Checksum...                      |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                              ...                              |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *

 *    The format for Keyed SHA1 and Meticulous Keyed SHA1 authentication is:

 *     0                   1                   2                   3

 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |   Auth Type   |   Auth Len    |  Auth Key ID  |   Reserved    |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                        Sequence Number                        |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                     Auth Key/Checksum...                      |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *    |                              ...                              |

 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 *

 *

 */

/* Given the type of authentication being used, return the required length of

 * the authentication header

 */

static uint8_t

get_bfd_required_auth_len(uint8_t auth_type)

{

    uint8_t auth_len = 0;

    switch (auth_type) {

        case BFD_AUTH_MD5:

        case BFD_AUTH_MET_MD5:

            auth_len = MD5_AUTH_LEN;

            break;

        case BFD_AUTH_SHA1:

        case BFD_AUTH_MET_SHA1:

            auth_len = SHA1_AUTH_LEN;

            break;

        default:

            break;

    }

    return auth_len;

}

/* Given the type of authentication being used, return the length of

 * checksum field

 */

static uint8_t

get_bfd_checksum_len(uint8_t auth_type)

{

    uint8_t checksum_len = 0;

    switch (auth_type) {

        case BFD_AUTH_MD5:

        case BFD_AUTH_MET_MD5:

            checksum_len = MD5_CHECKSUM_LEN;

            break;

        case BFD_AUTH_SHA1:

        case BFD_AUTH_MET_SHA1:

            checksum_len = SHA1_CHECKSUM_LEN;

            break;

        default:

            break;

    }

    return checksum_len;

}

static void

dissect_bfd_authentication(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)

{

    int           offset    = 24;

    uint8_t       auth_type;

    uint8_t       auth_len;

    proto_item   *auth_item = NULL;

    proto_tree   *auth_tree = NULL;

    const uint8_t *password;

    auth_type = tvb_get_uint8(tvb, offset);

    auth_len  = tvb_get_uint8(tvb, offset + 1);

    if (tree) {

        auth_tree = proto_tree_add_subtree_format(tree, tvb, offset, auth_len,

                                        ett_bfd_auth, NULL, "Authentication: %s",

                                        val_to_str(pinfo->pool, auth_type,

                                                   bfd_control_auth_type_values,

                                                   "Unknown Authentication Type (%d)") );

        proto_tree_add_item(auth_tree, hf_bfd_auth_type, tvb, offset, 1, ENC_BIG_ENDIAN);

        proto_tree_add_item(auth_tree, hf_bfd_auth_len, tvb, offset + 1, 1, ENC_BIG_ENDIAN);

        proto_tree_add_item(auth_tree, hf_bfd_auth_key, tvb, offset + 2, 1, ENC_BIG_ENDIAN);

    }

    switch (auth_type) {

        case BFD_AUTH_SIMPLE:

            proto_tree_add_item_ret_string(auth_tree, hf_bfd_auth_password, tvb, offset+3,

                                    auth_len-3, ENC_ASCII|ENC_NA, pinfo->pool, &password);

            proto_item_append_text(auth_item, ": %s", password);

            break;

        case BFD_AUTH_MD5:

        case BFD_AUTH_MET_MD5:

        case BFD_AUTH_SHA1:

        case BFD_AUTH_MET_SHA1:

            if (auth_len != get_bfd_required_auth_len(auth_type)) {

                proto_tree_add_expert_format(auth_tree, pinfo, &ei_bfd_auth_len_invalid, tvb, offset, auth_len,

                        "Length of authentication section (%d) is invalid for Authentication Type: %s",

                        auth_len, val_to_str(pinfo->pool, auth_type, bfd_control_auth_type_values, "Unknown Authentication Type (%d)") );

                proto_item_append_text(auth_item, ": Invalid Authentication Section");

            }

            if (tree) {

                proto_tree_add_item(auth_tree, hf_bfd_auth_seq_num, tvb, offset+4, 4, ENC_BIG_ENDIAN);

                proto_tree_add_item(auth_tree, hf_bfd_checksum, tvb, offset+8, get_bfd_checksum_len(auth_type), ENC_NA);

            }

            break;

        default:

            break;

    }

}

static int

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

{

    proto_tree *bfd_tree = NULL;

    unsigned bfd_length = tvb_reported_length_remaining(tvb, 0);

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "BFD Echo");

    /* XXX Add direction */

    col_set_str(pinfo->cinfo, COL_INFO, "Originator specific content");

    if (tree) {

        proto_item *ti;

        ti = proto_tree_add_protocol_format(tree, proto_bfd_echo, tvb, 0, bfd_length,

                                            "BFD Echo message");

        bfd_tree = proto_item_add_subtree(ti, ett_bfd_echo);

        proto_tree_add_item(bfd_tree, hf_bfd_echo, tvb, 0, bfd_length, ENC_NA);

    }

    return bfd_length;

}

static int

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

{

    unsigned flags;

    unsigned bfd_version;

    unsigned bfd_diag;

    unsigned bfd_sta        = 0;

    unsigned bfd_flags;

    unsigned bfd_flags_a    = 0;

    unsigned bfd_detect_time_multiplier;

    unsigned bfd_length;

    unsigned bfd_my_discriminator;

    unsigned bfd_your_discriminator;

    unsigned bfd_desired_min_tx_interval;

    unsigned bfd_required_min_rx_interval;

    unsigned bfd_required_min_echo_interval;

    proto_tree *bfd_tree = NULL;

    col_set_str(pinfo->cinfo, COL_PROTOCOL, "BFD Control");

    col_clear(pinfo->cinfo, COL_INFO);

    bfd_version = (tvb_get_uint8(tvb, 0) & 0xe0) >> 5;

    bfd_diag    = (tvb_get_uint8(tvb, 0) & 0x1f);

    flags       = tvb_get_uint8(tvb, 1);

    switch (bfd_version) {

        case 0:

            bfd_flags      = flags;

            break;

        case 1:

        default:

            bfd_sta        = flags & 0xc0;

            bfd_flags      = flags & 0x3e;

            bfd_flags_a    = flags & 0x04;

            break;

    }

    bfd_detect_time_multiplier     = tvb_get_uint8(tvb, 2);

    bfd_length                     = tvb_get_uint8(tvb, 3);

    bfd_my_discriminator           = tvb_get_ntohl(tvb, 4);

    bfd_your_discriminator         = tvb_get_ntohl(tvb, 8);

    bfd_desired_min_tx_interval    = tvb_get_ntohl(tvb, 12);

    bfd_required_min_rx_interval   = tvb_get_ntohl(tvb, 16);

    bfd_required_min_echo_interval = tvb_get_ntohl(tvb, 20);

    switch (bfd_version) {

        case 0:

            col_add_fstr(pinfo->cinfo, COL_INFO, "Diag: %s, Flags: 0x%02x",

                         val_to_str_const(bfd_diag, bfd_control_v0_diag_values, "Unknown"),

                         bfd_flags);

            break;

        case 1:

        default:

            col_add_fstr(pinfo->cinfo, COL_INFO, "Diag: %s, State: %s, Flags: 0x%02x",

                         val_to_str_const(bfd_diag, bfd_control_v1_diag_values, "Unknown"),

                         val_to_str_const(bfd_sta >> 6 , bfd_control_sta_values, "Unknown"),

                         bfd_flags);

            break;

    }

    if (tree) {

        proto_item *ti;

        ti = proto_tree_add_protocol_format(tree, proto_bfd, tvb, 0, bfd_length,

                                            "BFD Control message");

        bfd_tree = proto_item_add_subtree(ti, ett_bfd);

        proto_tree_add_uint(bfd_tree, hf_bfd_version, tvb, 0,

                                 1, bfd_version << 5);

        proto_tree_add_uint(bfd_tree, hf_bfd_diag, tvb, 0,

                                 1, bfd_diag);

        switch (bfd_version) {

            case 0:

                break;

            case 1:

            default:

                proto_tree_add_uint(bfd_tree, hf_bfd_sta, tvb, 1,

                                    1, bfd_sta);

                break;

        }

        switch (bfd_version) {

            case 0:

                {

                static int * const bfd_message_flags[] = {

                    &hf_bfd_flags_h,

                    &hf_bfd_flags_d_v0,

                    &hf_bfd_flags_p_v0,

                    &hf_bfd_flags_f_v0,

                    NULL

                };

                proto_tree_add_bitmask_with_flags(bfd_tree, tvb, 1, hf_bfd_flags, ett_bfd_flags, bfd_message_flags, ENC_NA, BMT_NO_FALSE);

                }

                break;

            case 1:

            default:

                {

                static int * const bfd_message_flags[] = {

                    &hf_bfd_flags_p,

                    &hf_bfd_flags_f,

                    &hf_bfd_flags_c,

                    &hf_bfd_flags_a,

                    &hf_bfd_flags_d,

                    &hf_bfd_flags_m,

                    NULL

                };

                proto_tree_add_bitmask_with_flags(bfd_tree, tvb, 1, hf_bfd_flags, ett_bfd_flags, bfd_message_flags, ENC_NA, BMT_NO_FALSE);

                }

                break;

        }

        proto_tree_add_uint_format_value(bfd_tree, hf_bfd_detect_time_multiplier, tvb, 2,

                                         1, bfd_detect_time_multiplier,

                                         "%u (= %u ms Detection time)",

                                         bfd_detect_time_multiplier,

                                         bfd_detect_time_multiplier * (bfd_desired_min_tx_interval/1000));

        proto_tree_add_uint(bfd_tree, hf_bfd_message_length, tvb, 3, 1, bfd_length);

        proto_tree_add_uint(bfd_tree, hf_bfd_my_discriminator, tvb, 4,

                                 4, bfd_my_discriminator);

        proto_tree_add_uint(bfd_tree, hf_bfd_your_discriminator, tvb, 8,

                                 4, bfd_your_discriminator);

        proto_tree_add_uint_format_value(bfd_tree, hf_bfd_desired_min_tx_interval, tvb, 12,

                                              4, bfd_desired_min_tx_interval,

                                              "%4u ms (%u us)",

                                              bfd_desired_min_tx_interval/1000,

                                              bfd_desired_min_tx_interval);

        proto_tree_add_uint_format_value(bfd_tree, hf_bfd_required_min_rx_interval, tvb, 16,

                                              4, bfd_required_min_rx_interval,

                                              "%4u ms (%u us)",

                                              bfd_required_min_rx_interval/1000,

                                              bfd_required_min_rx_interval);

        proto_tree_add_uint_format_value(bfd_tree, hf_bfd_required_min_echo_interval, tvb, 20,

                                              4, bfd_required_min_echo_interval,

                                              "%4u ms (%u us)",

                                              bfd_required_min_echo_interval/1000,

                                              bfd_required_min_echo_interval);

    } /* if (tree) */

    /* Dissect the authentication fields if the Authentication flag has

     * been set

     */

    if (bfd_version && bfd_flags_a) {

        if (bfd_length >= 28) {

            dissect_bfd_authentication(tvb, pinfo, bfd_tree);

        } else {

            proto_tree_add_expert_format(bfd_tree, pinfo, &ei_bfd_auth_no_data, tvb, 24, bfd_length-24,

                                         "Authentication: Length of the BFD frame is invalid (%d)", bfd_length);

        }

    }

    return tvb_captured_length(tvb);

}

/* BFD CV Source MEP-ID TLV Decoder,

   As per RFC 6428 : https://tools.ietf.org/html/rfc6428

   sections - 3.5.1, 3.5.2, 3.5.3 */

void

dissect_bfd_mep (tvbuff_t *tvb, proto_tree *tree, const int hfindex)

{

    proto_item *ti;

    proto_tree *bfd_tree;

    int         offset = 0;

    int         mep_type;

    int         mep_len;

    int         mep_agi_len;

    if (!tree)

        return;

    /* Fetch the BFD control message length and move the offset

       to point to the data portion after the control message */

    /* The parameter hfindex is used for determining the tree under which MEP-ID TLV

       has to be determined. Since according to RFC 6428, MEP-ID TLV can be used by any

       OAM function, if hfindex is 0, as per this function the MEP-TLV is a part of

       BFD-CV payload. If a non-zero hfindex comes, then tht TLV info will be displayed

       under a particular protocol-tree. */

    if (!hfindex)

      {

        offset   = tvb_get_uint8(tvb, 3);

        mep_type = tvb_get_ntohs (tvb, offset);

        mep_len  = tvb_get_ntohs (tvb, (offset + 2));

        ti       = proto_tree_add_protocol_format (tree, proto_bfd, tvb, offset, (mep_len + 4),

                                                   "MPLS-TP SOURCE MEP-ID TLV");

      }

    else

      {

        mep_type = tvb_get_ntohs (tvb, offset);

        mep_len  = tvb_get_ntohs (tvb, (offset + 2));

        ti       = proto_tree_add_protocol_format (tree, hfindex, tvb, offset, (mep_len + 4),

                                                   "MPLS-TP SOURCE MEP-ID TLV");

      }

    switch (mep_type) {

        case TLV_TYPE_MPLSTP_SECTION_MEP:

            bfd_tree = proto_item_add_subtree (ti, ett_bfd);

            proto_tree_add_uint (bfd_tree, hf_mep_type , tvb, offset,

                                 2, mep_type);

            proto_tree_add_uint (bfd_tree, hf_mep_len, tvb, (offset + 2),

                                 2, mep_len);

            proto_tree_add_item (bfd_tree, hf_mep_global_id, tvb, (offset + 4),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_node_id, tvb, (offset + 8),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_section_interface_no, tvb, (offset + 12),

                                 4, ENC_BIG_ENDIAN);

            break;

        case TLV_TYPE_MPLSTP_LSP_MEP:

            bfd_tree = proto_item_add_subtree (ti, ett_bfd);

            proto_tree_add_uint (bfd_tree, hf_mep_type , tvb, offset,

                                 2, mep_type);

            proto_tree_add_uint (bfd_tree, hf_mep_len, tvb, (offset + 2),

                                 2, mep_len);

            proto_tree_add_item (bfd_tree, hf_mep_global_id, tvb, (offset + 4),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_node_id, tvb, (offset + 8),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_tunnel_no, tvb, (offset + 12),

                                 2, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_lsp_no, tvb, (offset + 14),

                                 2, ENC_BIG_ENDIAN);

            break;

        case TLV_TYPE_MPLSTP_PW_MEP:

            mep_agi_len   = tvb_get_uint8 (tvb, (offset + 17));

            bfd_tree = proto_item_add_subtree (ti, ett_bfd);

            proto_tree_add_uint (bfd_tree, hf_mep_type, tvb, offset,

                                 2, (mep_type));

            proto_tree_add_uint (bfd_tree, hf_mep_len, tvb, (offset + 2),

                                 2, mep_len);

            proto_tree_add_item (bfd_tree, hf_mep_global_id, tvb, (offset + 4),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_node_id, tvb, (offset + 8),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_ac_id, tvb, (offset + 12),

                                 4, ENC_BIG_ENDIAN);

            proto_tree_add_item (bfd_tree, hf_mep_agi_type, tvb, (offset + 16),

                                 1, ENC_BIG_ENDIAN);

            proto_tree_add_uint (bfd_tree, hf_mep_agi_len, tvb, (offset + 17),

                                 1, mep_agi_len);

            proto_tree_add_item (bfd_tree, hf_mep_agi_val, tvb, (offset + 18),

                                 mep_agi_len, ENC_ASCII);

            break;

        default:

            break;

    }

    return;

}

/* Register the protocol with Wireshark */

void

proto_register_bfd(void)

{

    /* Setup list of header fields */

    static hf_register_info hf[] = {

        { &hf_bfd_version,

          { "Protocol Version", "bfd.version",

            FT_UINT8, BASE_DEC, NULL , 0xe0,

            "The version number of the BFD protocol", HFILL }

        },

        { &hf_bfd_diag,

          { "Diagnostic Code", "bfd.diag",

            FT_UINT8, BASE_HEX, VALS(bfd_control_v1_diag_values), 0x1f,

            "This field give the reason for a BFD session failure", HFILL }

        },

        { &hf_bfd_sta,

          { "Session State", "bfd.sta",

            FT_UINT8, BASE_HEX, VALS(bfd_control_sta_values), 0xc0,

            "The BFD state as seen by the transmitting system", HFILL }

        },

        { &hf_bfd_flags,

          { "Message Flags", "bfd.flags",

            FT_UINT8, BASE_HEX, NULL, 0x00,

            NULL, HFILL }

        },

        { &hf_bfd_flags_h,

          { "I hear you", "bfd.flags.h",

            FT_BOOLEAN, 8, TFS(&tfs_set_notset), 0x80,

            NULL, HFILL }

        },

        { &hf_bfd_flags_d_v0,

          { "Demand", "bfd.flags.d",

            FT_BOOLEAN, 8, TFS(&tfs_set_notset), 0x40,

            NULL, HFILL }

        },

        { &hf_bfd_flags_p_v0,

          { "Poll", "bfd.flags.p",

            FT_BOOLEAN, 8, TFS(&tfs_set_notset), 0x20,

            NULL, HFILL }

        },

        { &hf_bfd_flags_f_v0,

          { "Final", "bfd.flags.f",

            FT_BOOLEAN, 8, TFS(&tfs_set_notset), 0x10,

            NULL, HFILL }

        },

        { &hf_bfd_flags_p,

          { "Poll", "bfd.flags.p",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x20, /* 6 flag bits; Sta is shown separately */

            "If set, the transmitting system is expecting a packet with the Final (F) bit in reply",

            HFILL }

        },

        { &hf_bfd_flags_f,

          { "Final", "bfd.flags.f",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x10, /* 6 flag bits; Sta is shown separately */

            "If set, the transmitting system is replying to a packet with the Poll (P) bit set",

            HFILL }

        },

        { &hf_bfd_flags_c,

          { "Control Plane Independent", "bfd.flags.c",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x08, /* 6 flag bits; Sta is shown separately */

            "If set, the BFD implementation is implemented in the forwarding plane", HFILL }

        },

        { &hf_bfd_flags_a,

          { "Authentication Present", "bfd.flags.a",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x04, /* 6 flag bits; Sta is shown separately */

            "The Authentication Section is present", HFILL }

        },

        { &hf_bfd_flags_d,

          { "Demand", "bfd.flags.d",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x02, /* 6 flag bits; Sta is shown separately */

            "If set, Demand mode is active in the transmitting system", HFILL }

        },

        { &hf_bfd_flags_m,

          { "Multipoint", "bfd.flags.m",

            FT_BOOLEAN, 6, TFS(&tfs_set_notset), 0x01, /* 6 flag bits; Sta is shown separately */

            "Reserved for future point-to-multipoint extensions", HFILL }

        },

        { &hf_bfd_detect_time_multiplier,

          { "Detect Time Multiplier", "bfd.detect_time_multiplier",

            FT_UINT8, BASE_DEC, NULL, 0x0,

            "The transmit interval multiplied by this value is the failure detection time", HFILL }

        },

        { &hf_bfd_message_length,

          { "Message Length", "bfd.message_length",

            FT_UINT8, BASE_DEC|BASE_UNIT_STRING, UNS(&units_byte_bytes), 0x0,

            "Length of the BFD Control packet, in bytes", HFILL }

        },

        { &hf_bfd_my_discriminator,

          { "My Discriminator", "bfd.my_discriminator",

            FT_UINT32, BASE_HEX, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_bfd_your_discriminator,

          { "Your Discriminator", "bfd.your_discriminator",

            FT_UINT32, BASE_HEX, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_bfd_desired_min_tx_interval,

          { "Desired Min TX Interval", "bfd.desired_min_tx_interval",

            FT_UINT32, BASE_DEC, NULL, 0x0,

            "The minimum interval to use when transmitting BFD Control packets", HFILL }

        },

        { &hf_bfd_required_min_rx_interval,

          { "Required Min RX Interval", "bfd.required_min_rx_interval",

            FT_UINT32, BASE_DEC, NULL, 0x0,

            "The minimum interval between received BFD Control packets that this system can support", HFILL }

        },

        { &hf_bfd_required_min_echo_interval,

          { "Required Min Echo Interval", "bfd.required_min_echo_interval",

            FT_UINT32, BASE_DEC, NULL, 0x0,

            "The minimum interval between received BFD Echo packets that this system can support", HFILL }

        },

        { &hf_bfd_checksum,

          { "Checksum", "bfd.checksum",

            FT_BYTES, BASE_NONE, NULL, 0x0,

            NULL, HFILL }

        },

        { &hf_bfd_auth_type,

          { "Authentication Type", "bfd.auth.type",

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

            "The type of authentication in use on this session", HFILL }

        },

        { &hf_bfd_auth_len,

          { "Authentication Length", "bfd.auth.len",

            FT_UINT8, BASE_DEC|BASE_UNIT_STRING, UNS(&units_byte_bytes), 0x0,

            "The length, in bytes, of the authentication section", HFILL }

        },

        { &hf_bfd_auth_key,

          { "Authentication Key ID", "bfd.auth.key",

            FT_UINT8, BASE_DEC, NULL, 0x0,

            "The Authentication Key ID, identifies which password is in use for this packet", HFILL }

        },

        { &hf_bfd_auth_password,

          { "Password", "bfd.auth.password",

            FT_STRING, BASE_NONE, NULL, 0x0,

            "The simple password in use on this session", HFILL }

        },

        { &hf_bfd_auth_seq_num,

          { "Sequence Number", "bfd.auth.seq_num",

            FT_UINT32, BASE_HEX, NULL, 0x0,

            "The Sequence Number is periodically incremented to prevent replay attacks", HFILL }

          },

         { &hf_mep_type,

          { "Type", "bfd.mep.type",

            FT_UINT16, BASE_DEC, VALS(mplstp_mep_tlv_type_values), 0x0,

            "The type of the MEP Id", HFILL }

        },

        { &hf_mep_len,

          { "Length", "bfd.mep.len",

            FT_UINT16, BASE_DEC, NULL , 0x0,

            "The length of the MEP Id", HFILL }

        },

        { &hf_mep_global_id,

          { "Global Id", "bfd.mep.global.id",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            "MPLS-TP  Global  MEP Id", HFILL }

        },

        { &hf_mep_node_id,

          { "Node Id", "bfd.mep.node.id",

            FT_IPv4, BASE_NONE, NULL , 0x0,

            "MPLS-TP Node Identifier", HFILL }

        },

#if 0

        { &hf_mep_interface_no,

          { "Interface  Number", "bfd.mep.interface.no",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            "MPLS-TP Interface Number", HFILL }

        },

#endif

        { &hf_mep_tunnel_no,

          { "Tunnel Number", "bfd.mep.tunnel.no",

            FT_UINT16, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mep_lsp_no,

          { "LSP Number", "bfd.mep.lsp.no",

            FT_UINT16, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mep_ac_id,

          { "AC Id", "bfd.mep.ac.id",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mep_agi_type,

          { "AGI TYPE", "bfd.mep.agi.type",

            FT_UINT8, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mep_agi_len,

          { "AGI Length", "bfd.mep.agi.len",

            FT_UINT8, BASE_DEC, NULL , 0x0,

            NULL, HFILL }

        },

        { &hf_mep_agi_val,

           { "AGI value", "bfd.mep.agi.val",

             FT_STRING, BASE_NONE, NULL , 0x0,

             NULL, HFILL }

        },

        { &hf_section_interface_no,

          { "Interface Number", "bfd.mep.interface.no",

            FT_UINT32, BASE_DEC, NULL , 0x0,

            "MPLS-TP Interface Number", HFILL }

        }

    };

    /* BFD Echo */

    static hf_register_info hf_echo[] = {

        { &hf_bfd_echo,

          { "Echo", "bfd_echo.packet",

            FT_BYTES, BASE_NONE, NULL, 0x0,

            "Originator specific echo packet", HFILL }

        }

    };

    /* Setup protocol subtree array */

    static int *ett[] = {

        &ett_bfd,

        &ett_bfd_flags,

        &ett_bfd_auth,

        &ett_bfd_echo

    };

    static ei_register_info ei[] = {

        { &ei_bfd_auth_len_invalid, { "bfd.auth.len.invalid", PI_MALFORMED, PI_WARN, "Length of authentication section is invalid", EXPFILL }},

        { &ei_bfd_auth_no_data, { "bfd.auth.no_data", PI_MALFORMED, PI_WARN, "Authentication flag is set in a BFD packet, but no authentication data is present", EXPFILL }},

    };

    expert_module_t* expert_bfd;

    /* Register the protocol name and description */

    proto_bfd = proto_register_protocol("Bidirectional Forwarding Detection Control Message",

                                        "BFD Control",

                                        "bfd");

    proto_bfd_echo = proto_register_protocol("Bidirectional Forwarding Detection Echo Packet",

                                        "BFD Echo",

                                        "bfd_echo");

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

    proto_register_field_array(proto_bfd, hf, array_length(hf));

    proto_register_field_array(proto_bfd_echo, hf_echo, array_length(hf_echo));

    proto_register_subtree_array(ett, array_length(ett));

    expert_bfd = expert_register_protocol(proto_bfd);

    expert_register_field_array(expert_bfd, ei, array_length(ei));

    /* Register dissectors */

    bfd_control_handle = register_dissector("bfd", dissect_bfd_control, proto_bfd);

    bfd_echo_handle = register_dissector("bfd_echo", dissect_bfd_echo, proto_bfd_echo);

}

void

proto_reg_handoff_bfd(void)

{

    dissector_add_uint_range_with_preference("udp.port", UDP_PORT_RANGE_BFD_CTRL, bfd_control_handle);

    dissector_add_uint("udp.port", UDP_PORT_BFD_ECHO, bfd_echo_handle);

    dissector_add_uint("pwach.channel_type", PW_ACH_TYPE_BFD_CC, bfd_control_handle);

    dissector_add_uint("pwach.channel_type", PW_ACH_TYPE_BFD_CV, bfd_control_handle);

    dissector_add_uint("pwach.channel_type", PW_ACH_TYPE_BFD, bfd_control_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:

 */