xref: /src/external/bsd/tcpdump/dist/print-slow.c

/*
 * Copyright (c) 1998-2006 The TCPDUMP project
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code
 * distributions retain the above copyright notice and this paragraph
 * in its entirety, and (2) distributions including binary code include
 * the above copyright notice and this paragraph in its entirety in
 * the documentation or other materials provided with the distribution.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 *
 * support for the IEEE "slow protocols" LACP, MARKER as per 802.3ad
 *                                       OAM as per 802.3ah
 *
 * Original code by Hannes Gredler (hannes (at) juniper.net)
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static const char rcsid[] _U_ =
    "@(#) Header: /tcpdump/master/tcpdump/print-slow.c,v 1.8 2006-10-12 05:44:33 hannes Exp";
#else
__RCSID("$NetBSD: print-slow.c,v 1.3 2012/01/16 17:34:18 christos Exp $");
#endif
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <tcpdump-stdinc.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "interface.h"
#include "extract.h"
#include "addrtoname.h"
#include "ether.h"
#include "oui.h"

struct slow_common_header_t {
    u_int8_t proto_subtype;
    u_int8_t version;
};

#define	SLOW_PROTO_LACP                     1
#define	SLOW_PROTO_MARKER                   2
#define SLOW_PROTO_OAM                      3

#define	LACP_VERSION                        1
#define	MARKER_VERSION                      1

static const struct tok slow_proto_values[] = {
    { SLOW_PROTO_LACP, "LACP" },
    { SLOW_PROTO_MARKER, "MARKER" },
    { SLOW_PROTO_OAM, "OAM" },
    { 0, NULL}
};

static const struct tok slow_oam_flag_values[] = {
    { 0x0001, "Link Fault" },
    { 0x0002, "Dying Gasp" },
    { 0x0004, "Critical Event" },
    { 0x0008, "Local Evaluating" },
    { 0x0010, "Local Stable" },
    { 0x0020, "Remote Evaluating" },
    { 0x0040, "Remote Stable" },
    { 0, NULL}
};

#define SLOW_OAM_CODE_INFO          0x00
#define SLOW_OAM_CODE_EVENT_NOTIF   0x01
#define SLOW_OAM_CODE_VAR_REQUEST   0x02
#define SLOW_OAM_CODE_VAR_RESPONSE  0x03
#define SLOW_OAM_CODE_LOOPBACK_CTRL 0x04
#define SLOW_OAM_CODE_PRIVATE       0xfe

static const struct tok slow_oam_code_values[] = {
    { SLOW_OAM_CODE_INFO, "Information" },
    { SLOW_OAM_CODE_EVENT_NOTIF, "Event Notification" },
    { SLOW_OAM_CODE_VAR_REQUEST, "Variable Request" },
    { SLOW_OAM_CODE_VAR_RESPONSE, "Variable Response" },
    { SLOW_OAM_CODE_LOOPBACK_CTRL, "Loopback Control" },
    { SLOW_OAM_CODE_PRIVATE, "Vendor Private" },
    { 0, NULL}
};

struct slow_oam_info_t {
    u_int8_t info_type;
    u_int8_t info_length;
    u_int8_t oam_version;
    u_int8_t revision[2];
    u_int8_t state;
    u_int8_t oam_config;
    u_int8_t oam_pdu_config[2];
    u_int8_t oui[3];
    u_int8_t vendor_private[4];
};

#define SLOW_OAM_INFO_TYPE_END_OF_TLV 0x00
#define SLOW_OAM_INFO_TYPE_LOCAL 0x01
#define SLOW_OAM_INFO_TYPE_REMOTE 0x02
#define SLOW_OAM_INFO_TYPE_ORG_SPECIFIC 0xfe

static const struct tok slow_oam_info_type_values[] = {
    { SLOW_OAM_INFO_TYPE_END_OF_TLV, "End of TLV marker" },
    { SLOW_OAM_INFO_TYPE_LOCAL, "Local" },
    { SLOW_OAM_INFO_TYPE_REMOTE, "Remote" },
    { SLOW_OAM_INFO_TYPE_ORG_SPECIFIC, "Organization specific" },
    { 0, NULL}
};

#define OAM_INFO_TYPE_PARSER_MASK 0x3
static const struct tok slow_oam_info_type_state_parser_values[] = {
    { 0x00, "forwarding" },
    { 0x01, "looping back" },
    { 0x02, "discarding" },
    { 0x03, "reserved" },
    { 0, NULL}
};

#define OAM_INFO_TYPE_MUX_MASK 0x4
static const struct tok slow_oam_info_type_state_mux_values[] = {
    { 0x00, "forwarding" },
    { 0x04, "discarding" },
    { 0, NULL}
};

static const struct tok slow_oam_info_type_oam_config_values[] = {
    { 0x01, "Active" },
    { 0x02, "Unidirectional" },
    { 0x04, "Remote-Loopback" },
    { 0x08, "Link-Events" },
    { 0x10, "Variable-Retrieval" },
    { 0, NULL}
};

/* 11 Bits */
#define OAM_INFO_TYPE_PDU_SIZE_MASK 0x7ff

#define SLOW_OAM_LINK_EVENT_END_OF_TLV 0x00
#define SLOW_OAM_LINK_EVENT_ERR_SYM_PER 0x01
#define SLOW_OAM_LINK_EVENT_ERR_FRM 0x02
#define SLOW_OAM_LINK_EVENT_ERR_FRM_PER 0x03
#define SLOW_OAM_LINK_EVENT_ERR_FRM_SUMM 0x04
#define SLOW_OAM_LINK_EVENT_ORG_SPECIFIC 0xfe

static const struct tok slow_oam_link_event_values[] = {
    { SLOW_OAM_LINK_EVENT_END_OF_TLV, "End of TLV marker" },
    { SLOW_OAM_LINK_EVENT_ERR_SYM_PER, "Errored Symbol Period Event" },
    { SLOW_OAM_LINK_EVENT_ERR_FRM, "Errored Frame Event" },
    { SLOW_OAM_LINK_EVENT_ERR_FRM_PER, "Errored Frame Period Event" },
    { SLOW_OAM_LINK_EVENT_ERR_FRM_SUMM, "Errored Frame Seconds Summary Event" },
    { SLOW_OAM_LINK_EVENT_ORG_SPECIFIC, "Organization specific" },
    { 0, NULL}
};

struct slow_oam_link_event_t {
    u_int8_t event_type;
    u_int8_t event_length;
    u_int8_t time_stamp[2];
    u_int8_t window[8];
    u_int8_t threshold[8];
    u_int8_t errors[8];
    u_int8_t errors_running_total[8];
    u_int8_t event_running_total[4];
};

struct slow_oam_variablerequest_t {
    u_int8_t branch;
    u_int8_t leaf[2];
};

struct slow_oam_variableresponse_t {
    u_int8_t branch;
    u_int8_t leaf[2];
    u_int8_t length;
};

struct slow_oam_loopbackctrl_t {
    u_int8_t command;
};

static const struct tok slow_oam_loopbackctrl_cmd_values[] = {
    { 0x01, "Enable OAM Remote Loopback" },
    { 0x02, "Disable OAM Remote Loopback" },
    { 0, NULL}
};

struct tlv_header_t {
    u_int8_t type;
    u_int8_t length;
};

#define LACP_TLV_TERMINATOR     0x00
#define LACP_TLV_ACTOR_INFO     0x01
#define LACP_TLV_PARTNER_INFO   0x02
#define LACP_TLV_COLLECTOR_INFO 0x03

#define MARKER_TLV_TERMINATOR   0x00
#define MARKER_TLV_MARKER_INFO  0x01

static const struct tok slow_tlv_values[] = {
    { (SLOW_PROTO_LACP << 8) + LACP_TLV_TERMINATOR, "Terminator"},
    { (SLOW_PROTO_LACP << 8) + LACP_TLV_ACTOR_INFO, "Actor Information"},
    { (SLOW_PROTO_LACP << 8) + LACP_TLV_PARTNER_INFO, "Partner Information"},
    { (SLOW_PROTO_LACP << 8) + LACP_TLV_COLLECTOR_INFO, "Collector Information"},

    { (SLOW_PROTO_MARKER << 8) + MARKER_TLV_TERMINATOR, "Terminator"},
    { (SLOW_PROTO_MARKER << 8) + MARKER_TLV_MARKER_INFO, "Marker Information"},
    { 0, NULL}
};

struct lacp_tlv_actor_partner_info_t {
    u_int8_t sys_pri[2];
    u_int8_t sys[ETHER_ADDR_LEN];
    u_int8_t key[2];
    u_int8_t port_pri[2];
    u_int8_t port[2];
    u_int8_t state;
    u_int8_t pad[3];
};

static const struct tok lacp_tlv_actor_partner_info_state_values[] = {
    { 0x01, "Activity"},
    { 0x02, "Timeout"},
    { 0x04, "Aggregation"},
    { 0x08, "Synchronization"},
    { 0x10, "Collecting"},
    { 0x20, "Distributing"},
    { 0x40, "Default"},
    { 0x80, "Expired"},
    { 0, NULL}
};

struct lacp_tlv_collector_info_t {
    u_int8_t max_delay[2];
    u_int8_t pad[12];
};

struct marker_tlv_marker_info_t {
    u_int8_t req_port[2];
    u_int8_t req_sys[ETHER_ADDR_LEN];
    u_int8_t req_trans_id[4];
    u_int8_t pad[2];
};

struct lacp_marker_tlv_terminator_t {
    u_int8_t pad[50];
};

void slow_marker_lacp_print(register const u_char *, register u_int);
void slow_oam_print(register const u_char *, register u_int);

const struct slow_common_header_t *slow_com_header;

void
slow_print(register const u_char *pptr, register u_int len) {

    int print_version;

    slow_com_header = (const struct slow_common_header_t *)pptr;
    TCHECK(*slow_com_header);

    /*
     * Sanity checking of the header.
     */
    switch (slow_com_header->proto_subtype) {
    case SLOW_PROTO_LACP:
        if (slow_com_header->version != LACP_VERSION) {
            printf("LACP version %u packet not supported",slow_com_header->version);
            return;
        }
        print_version = 1;
        break;

    case SLOW_PROTO_MARKER:
        if (slow_com_header->version != MARKER_VERSION) {
            printf("MARKER version %u packet not supported",slow_com_header->version);
            return;
        }
        print_version = 1;
        break;

    case SLOW_PROTO_OAM: /* fall through */
        print_version = 0;
        break;

    default:
        /* print basic information and exit */
        print_version = -1;
        break;
    }

    if (print_version) {
        printf("%sv%u, length %u",
               tok2str(slow_proto_values, "unknown (%u)",slow_com_header->proto_subtype),
               slow_com_header->version,
               len);
    } else {
        /* some slow protos don't have a version number in the header */
        printf("%s, length %u",
               tok2str(slow_proto_values, "unknown (%u)",slow_com_header->proto_subtype),
               len);
    }

    /* unrecognized subtype */
    if (print_version == -1) {
        print_unknown_data(pptr, "\n\t", len);
        return;
    }

    if (!vflag)
        return;

    switch (slow_com_header->proto_subtype) {
    default: /* should not happen */
        break;

    case SLOW_PROTO_OAM:
        /* skip proto_subtype */
        slow_oam_print(pptr+1, len-1);
        break;

    case SLOW_PROTO_LACP:   /* LACP and MARKER share the same semantics */
    case SLOW_PROTO_MARKER:
        /* skip slow_common_header */
        len -= sizeof(const struct slow_common_header_t);
        pptr += sizeof(const struct slow_common_header_t);
        slow_marker_lacp_print(pptr, len);
        break;
    }
    return;

trunc:
    printf("\n\t\t packet exceeded snapshot");
}

void slow_marker_lacp_print(register const u_char *tptr, register u_int tlen) {

    const struct tlv_header_t *tlv_header;
    const u_char *tlv_tptr;
    u_int tlv_len, tlv_tlen;

    union {
        const struct lacp_marker_tlv_terminator_t *lacp_marker_tlv_terminator;
        const struct lacp_tlv_actor_partner_info_t *lacp_tlv_actor_partner_info;
        const struct lacp_tlv_collector_info_t *lacp_tlv_collector_info;
        const struct marker_tlv_marker_info_t *marker_tlv_marker_info;
    } tlv_ptr;

    while(tlen>0) {
        /* did we capture enough for fully decoding the tlv header ? */
        TCHECK2(*tptr, sizeof(struct tlv_header_t));
        tlv_header = (const struct tlv_header_t *)tptr;
        tlv_len = tlv_header->length;

        printf("\n\t%s TLV (0x%02x), length %u",
               tok2str(slow_tlv_values,
                       "Unknown",
                       (slow_com_header->proto_subtype << 8) + tlv_header->type),
               tlv_header->type,
               tlv_len);

        if ((tlv_len < sizeof(struct tlv_header_t) ||
            tlv_len > tlen) &&
            tlv_header->type != LACP_TLV_TERMINATOR &&
            tlv_header->type != MARKER_TLV_TERMINATOR) {
            printf("\n\t-----trailing data-----");
            print_unknown_data(tptr+sizeof(struct tlv_header_t),"\n\t  ",tlen);
            return;
        }

        tlv_tptr=tptr+sizeof(struct tlv_header_t);
        tlv_tlen=tlv_len-sizeof(struct tlv_header_t);

        /* did we capture enough for fully decoding the tlv ? */
        TCHECK2(*tptr, tlv_len);

        switch((slow_com_header->proto_subtype << 8) + tlv_header->type) {

            /* those two TLVs have the same structure -> fall through */
        case ((SLOW_PROTO_LACP << 8) + LACP_TLV_ACTOR_INFO):
        case ((SLOW_PROTO_LACP << 8) + LACP_TLV_PARTNER_INFO):
            tlv_ptr.lacp_tlv_actor_partner_info = (const struct lacp_tlv_actor_partner_info_t *)tlv_tptr;

            printf("\n\t  System %s, System Priority %u, Key %u" \
                   ", Port %u, Port Priority %u\n\t  State Flags [%s]",
                   etheraddr_string(tlv_ptr.lacp_tlv_actor_partner_info->sys),
                   EXTRACT_16BITS(tlv_ptr.lacp_tlv_actor_partner_info->sys_pri),
                   EXTRACT_16BITS(tlv_ptr.lacp_tlv_actor_partner_info->key),
                   EXTRACT_16BITS(tlv_ptr.lacp_tlv_actor_partner_info->port),
                   EXTRACT_16BITS(tlv_ptr.lacp_tlv_actor_partner_info->port_pri),
                   bittok2str(lacp_tlv_actor_partner_info_state_values,
                              "none",
                              tlv_ptr.lacp_tlv_actor_partner_info->state));

            break;

        case ((SLOW_PROTO_LACP << 8) + LACP_TLV_COLLECTOR_INFO):
            tlv_ptr.lacp_tlv_collector_info = (const struct lacp_tlv_collector_info_t *)tlv_tptr;

            printf("\n\t  Max Delay %u",
                   EXTRACT_16BITS(tlv_ptr.lacp_tlv_collector_info->max_delay));

            break;

        case ((SLOW_PROTO_MARKER << 8) + MARKER_TLV_MARKER_INFO):
            tlv_ptr.marker_tlv_marker_info = (const struct marker_tlv_marker_info_t *)tlv_tptr;

            printf("\n\t  Request System %s, Request Port %u, Request Transaction ID 0x%08x",
                   etheraddr_string(tlv_ptr.marker_tlv_marker_info->req_sys),
                   EXTRACT_16BITS(tlv_ptr.marker_tlv_marker_info->req_port),
                   EXTRACT_32BITS(tlv_ptr.marker_tlv_marker_info->req_trans_id));

            break;

            /* those two TLVs have the same structure -> fall through */
        case ((SLOW_PROTO_LACP << 8) + LACP_TLV_TERMINATOR):
        case ((SLOW_PROTO_MARKER << 8) + LACP_TLV_TERMINATOR):
            tlv_ptr.lacp_marker_tlv_terminator = (const struct lacp_marker_tlv_terminator_t *)tlv_tptr;
            if (tlv_len == 0) {
                tlv_len = sizeof(tlv_ptr.lacp_marker_tlv_terminator->pad) +
                    sizeof(struct tlv_header_t);
                /* tell the user that we modified the length field  */
                if (vflag>1)
                    printf(" (=%u)",tlv_len);
                /* we have messed around with the length field - now we need to check
                 * again if there are enough bytes on the wire for the hexdump */
                TCHECK2(tlv_ptr.lacp_marker_tlv_terminator->pad[0],
                        sizeof(tlv_ptr.lacp_marker_tlv_terminator->pad));
            }

            break;

        default:
            if (vflag <= 1)
                print_unknown_data(tlv_tptr,"\n\t  ",tlv_tlen);
            break;
        }
        /* do we want to see an additional hexdump ? */
        if (vflag > 1) {
            print_unknown_data(tptr+sizeof(struct tlv_header_t),"\n\t  ",
                               tlv_len-sizeof(struct tlv_header_t));
        }

        tptr+=tlv_len;
        tlen-=tlv_len;
    }
    return;
trunc:
    printf("\n\t\t packet exceeded snapshot");
}

void slow_oam_print(register const u_char *tptr, register u_int tlen) {

    u_int hexdump;

    struct slow_oam_common_header_t {
        u_int8_t flags[2];
        u_int8_t code;
    };

    struct slow_oam_tlv_header_t {
        u_int8_t type;
        u_int8_t length;
    };

    union {
        const struct slow_oam_common_header_t *slow_oam_common_header;
        const struct slow_oam_tlv_header_t *slow_oam_tlv_header;
    } ptr;

    union {
	const struct slow_oam_info_t *slow_oam_info;
        const struct slow_oam_link_event_t *slow_oam_link_event;
        const struct slow_oam_variablerequest_t *slow_oam_variablerequest;
        const struct slow_oam_variableresponse_t *slow_oam_variableresponse;
        const struct slow_oam_loopbackctrl_t *slow_oam_loopbackctrl;
    } tlv;

    ptr.slow_oam_common_header = (struct slow_oam_common_header_t *)tptr;
    tptr += sizeof(struct slow_oam_common_header_t);
    tlen -= sizeof(struct slow_oam_common_header_t);

    printf("\n\tCode %s OAM PDU, Flags [%s]",
           tok2str(slow_oam_code_values, "Unknown (%u)", ptr.slow_oam_common_header->code),
           bittok2str(slow_oam_flag_values,
                      "none",
                      EXTRACT_16BITS(&ptr.slow_oam_common_header->flags)));

    switch (ptr.slow_oam_common_header->code) {
    case SLOW_OAM_CODE_INFO:
        while (tlen > 0) {
            ptr.slow_oam_tlv_header = (const struct slow_oam_tlv_header_t *)tptr;
            printf("\n\t  %s Information Type (%u), length %u",
                   tok2str(slow_oam_info_type_values, "Reserved",
                           ptr.slow_oam_tlv_header->type),
                   ptr.slow_oam_tlv_header->type,
                   ptr.slow_oam_tlv_header->length);

            hexdump = FALSE;
            switch (ptr.slow_oam_tlv_header->type) {
            case SLOW_OAM_INFO_TYPE_END_OF_TLV:
                if (ptr.slow_oam_tlv_header->length != 0) {
                    printf("\n\t    ERROR: illegal length - should be 0");
                }
                return;

            case SLOW_OAM_INFO_TYPE_LOCAL: /* identical format - fall through */
            case SLOW_OAM_INFO_TYPE_REMOTE:
                tlv.slow_oam_info = (const struct slow_oam_info_t *)tptr;

                if (tlv.slow_oam_info->info_length !=
                    sizeof(struct slow_oam_info_t)) {
                    printf("\n\t    ERROR: illegal length - should be %lu",
                           (unsigned long) sizeof(struct slow_oam_info_t));
                    return;
                }

                printf("\n\t    OAM-Version %u, Revision %u",
                       tlv.slow_oam_info->oam_version,
                       EXTRACT_16BITS(&tlv.slow_oam_info->revision));

                printf("\n\t    State-Parser-Action %s, State-MUX-Action %s",
                       tok2str(slow_oam_info_type_state_parser_values, "Reserved",
                               tlv.slow_oam_info->state & OAM_INFO_TYPE_PARSER_MASK),
                       tok2str(slow_oam_info_type_state_mux_values, "Reserved",
                               tlv.slow_oam_info->state & OAM_INFO_TYPE_MUX_MASK));
                printf("\n\t    OAM-Config Flags [%s], OAM-PDU-Config max-PDU size %u",
                       bittok2str(slow_oam_info_type_oam_config_values, "none",
                                  tlv.slow_oam_info->oam_config),
                       EXTRACT_16BITS(&tlv.slow_oam_info->oam_pdu_config) &
                       OAM_INFO_TYPE_PDU_SIZE_MASK);
                printf("\n\t    OUI %s (0x%06x), Vendor-Private 0x%08x",
                       tok2str(oui_values, "Unknown",
                               EXTRACT_24BITS(&tlv.slow_oam_info->oui)),
                       EXTRACT_24BITS(&tlv.slow_oam_info->oui),
                       EXTRACT_32BITS(&tlv.slow_oam_info->vendor_private));
                break;

            case SLOW_OAM_INFO_TYPE_ORG_SPECIFIC:
                hexdump = TRUE;
                break;

            default:
                hexdump = TRUE;
                break;
            }

            /* infinite loop check */
            if (!ptr.slow_oam_tlv_header->length) {
                return;
            }

            /* do we also want to see a hex dump ? */
            if (vflag > 1 || hexdump==TRUE) {
                print_unknown_data(tptr,"\n\t  ",
                                   ptr.slow_oam_tlv_header->length);
            }

            tlen -= ptr.slow_oam_tlv_header->length;
            tptr += ptr.slow_oam_tlv_header->length;
        }
        break;

    case SLOW_OAM_CODE_EVENT_NOTIF:
        while (tlen > 0) {
            ptr.slow_oam_tlv_header = (const struct slow_oam_tlv_header_t *)tptr;
            printf("\n\t  %s Link Event Type (%u), length %u",
                   tok2str(slow_oam_link_event_values, "Reserved",
                           ptr.slow_oam_tlv_header->type),
                   ptr.slow_oam_tlv_header->type,
                   ptr.slow_oam_tlv_header->length);

            hexdump = FALSE;
            switch (ptr.slow_oam_tlv_header->type) {
            case SLOW_OAM_LINK_EVENT_END_OF_TLV:
                if (ptr.slow_oam_tlv_header->length != 0) {
                    printf("\n\t    ERROR: illegal length - should be 0");
                }
                return;

            case SLOW_OAM_LINK_EVENT_ERR_SYM_PER: /* identical format - fall through */
            case SLOW_OAM_LINK_EVENT_ERR_FRM:
            case SLOW_OAM_LINK_EVENT_ERR_FRM_PER:
            case SLOW_OAM_LINK_EVENT_ERR_FRM_SUMM:
                tlv.slow_oam_link_event = (const struct slow_oam_link_event_t *)tptr;

                if (tlv.slow_oam_link_event->event_length !=
                    sizeof(struct slow_oam_link_event_t)) {
                    printf("\n\t    ERROR: illegal length - should be %lu",
                           (unsigned long) sizeof(struct slow_oam_link_event_t));
                    return;
                }

                printf("\n\t    Timestamp %u ms, Errored Window %" PRIu64
                       "\n\t    Errored Threshold %" PRIu64
                       "\n\t    Errors %" PRIu64
                       "\n\t    Error Running Total %" PRIu64
                       "\n\t    Event Running Total %u",
                       EXTRACT_16BITS(&tlv.slow_oam_link_event->time_stamp)*100,
                       EXTRACT_64BITS(&tlv.slow_oam_link_event->window),
                       EXTRACT_64BITS(&tlv.slow_oam_link_event->threshold),
                       EXTRACT_64BITS(&tlv.slow_oam_link_event->errors),
                       EXTRACT_64BITS(&tlv.slow_oam_link_event->errors_running_total),
                       EXTRACT_32BITS(&tlv.slow_oam_link_event->event_running_total));
                break;

            case SLOW_OAM_LINK_EVENT_ORG_SPECIFIC:
                hexdump = TRUE;
                break;

            default:
                hexdump = TRUE;
                break;
            }

            /* infinite loop check */
            if (!ptr.slow_oam_tlv_header->length) {
                return;
            }

            /* do we also want to see a hex dump ? */
            if (vflag > 1 || hexdump==TRUE) {
                print_unknown_data(tptr,"\n\t  ",
                                   ptr.slow_oam_tlv_header->length);
            }

            tlen -= ptr.slow_oam_tlv_header->length;
            tptr += ptr.slow_oam_tlv_header->length;
        }
        break;

    case SLOW_OAM_CODE_LOOPBACK_CTRL:
        tlv.slow_oam_loopbackctrl = (const struct slow_oam_loopbackctrl_t *)tptr;
        printf("\n\t  Command %s (%u)",
               tok2str(slow_oam_loopbackctrl_cmd_values,
                       "Unknown",
                       tlv.slow_oam_loopbackctrl->command),
               tlv.slow_oam_loopbackctrl->command);
               tptr ++;
               tlen --;
        break;

        /*
         * FIXME those are the defined codes that lack a decoder
         * you are welcome to contribute code ;-)
         */
    case SLOW_OAM_CODE_VAR_REQUEST:
    case SLOW_OAM_CODE_VAR_RESPONSE:
    case SLOW_OAM_CODE_PRIVATE:
    default:
        if (vflag <= 1) {
            print_unknown_data(tptr,"\n\t  ", tlen);
        }
        break;
    }
    return;
}