xref: /freebsd-current/contrib/tcpdump/print-olsr.c

/*
 * Copyright (c) 1998-2007 The TCPDUMP project
 * Copyright (c) 2009  Florian Forster
 *
 * 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.
 *
 * Original code by Hannes Gredler <hannes@gredler.at>
 * IPv6 additions by Florian Forster <octo at verplant.org>
 */

/* \summary: Optimized Link State Routing Protocol (OLSR) printer */

/* specification: RFC 3626 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "netdissect-stdinc.h"

#include "netdissect.h"
#include "addrtoname.h"
#include "extract.h"

/*
 * RFC 3626 common header
 *
 *  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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |         Packet Length         |    Packet Sequence Number     |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Message Type |     Vtime     |         Message Size          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                      Originator Address                       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Time To Live |   Hop Count   |    Message Sequence Number    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                                                               |
 * :                            MESSAGE                            :
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Message Type |     Vtime     |         Message Size          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                      Originator Address                       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Time To Live |   Hop Count   |    Message Sequence Number    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                                                               |
 * :                            MESSAGE                            :
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * :                                                               :
 */

struct olsr_common {
    nd_uint16_t packet_len;
    nd_uint16_t packet_seq;
};

#define OLSR_HELLO_MSG         1 /* rfc3626 */
#define OLSR_TC_MSG            2 /* rfc3626 */
#define OLSR_MID_MSG           3 /* rfc3626 */
#define OLSR_HNA_MSG           4 /* rfc3626 */
#define OLSR_POWERINFO_MSG   128
#define OLSR_NAMESERVICE_MSG 130
#define OLSR_HELLO_LQ_MSG    201 /* LQ extensions olsr.org */
#define OLSR_TC_LQ_MSG       202 /* LQ extensions olsr.org */

static const struct tok olsr_msg_values[] = {
    { OLSR_HELLO_MSG, "Hello" },
    { OLSR_TC_MSG, "TC" },
    { OLSR_MID_MSG, "MID" },
    { OLSR_HNA_MSG, "HNA" },
    { OLSR_POWERINFO_MSG, "Powerinfo" },
    { OLSR_NAMESERVICE_MSG, "Nameservice" },
    { OLSR_HELLO_LQ_MSG, "Hello-LQ" },
    { OLSR_TC_LQ_MSG, "TC-LQ" },
    { 0, NULL}
};

struct olsr_msg4 {
    nd_uint8_t  msg_type;
    nd_uint8_t  vtime;
    nd_uint16_t msg_len;
    nd_ipv4     originator;
    nd_uint8_t  ttl;
    nd_uint8_t  hopcount;
    nd_uint16_t msg_seq;
};

struct olsr_msg6 {
    nd_uint8_t  msg_type;
    nd_uint8_t  vtime;
    nd_uint16_t msg_len;
    nd_ipv6     originator;
    nd_uint8_t  ttl;
    nd_uint8_t  hopcount;
    nd_uint16_t msg_seq;
};

struct olsr_hello {
    nd_byte     res[2];
    nd_uint8_t  htime;
    nd_uint8_t  will;
};

struct olsr_hello_link {
    nd_uint8_t  link_code;
    nd_byte     res;
    nd_uint16_t len;
};

struct olsr_tc {
    nd_uint16_t ans_seq;
    nd_byte     res[2];
};

struct olsr_hna4 {
    nd_ipv4 network;
    nd_ipv4 mask;
};

struct olsr_hna6 {
    nd_ipv6 network;
    nd_ipv6 mask;
};


/** gateway HNA flags */
enum gateway_hna_flags {
  GW_HNA_FLAG_LINKSPEED   = 1 << 0,
  GW_HNA_FLAG_IPV4        = 1 << 1,
  GW_HNA_FLAG_IPV4_NAT    = 1 << 2,
  GW_HNA_FLAG_IPV6        = 1 << 3,
  GW_HNA_FLAG_IPV6PREFIX  = 1 << 4
};

/** gateway HNA field byte offsets in the netmask field of the HNA */
enum gateway_hna_fields {
  GW_HNA_PAD              = 0,
  GW_HNA_FLAGS            = 1,
  GW_HNA_UPLINK           = 2,
  GW_HNA_DOWNLINK         = 3,
  GW_HNA_V6PREFIXLEN      = 4,
  GW_HNA_V6PREFIX         = 5
};


#define OLSR_EXTRACT_LINK_TYPE(link_code) (link_code & 0x3)
#define OLSR_EXTRACT_NEIGHBOR_TYPE(link_code) (link_code >> 2)

static const struct tok olsr_link_type_values[] = {
    { 0, "Unspecified" },
    { 1, "Asymmetric" },
    { 2, "Symmetric" },
    { 3, "Lost" },
    { 0, NULL}
};

static const struct tok olsr_neighbor_type_values[] = {
    { 0, "Not-Neighbor" },
    { 1, "Symmetric" },
    { 2, "Symmetric-MPR" },
    { 0, NULL}
};

struct olsr_lq_neighbor4 {
    nd_ipv4     neighbor;
    nd_uint8_t  link_quality;
    nd_uint8_t  neighbor_link_quality;
    nd_byte     res[2];
};

struct olsr_lq_neighbor6 {
    nd_ipv6     neighbor;
    nd_uint8_t  link_quality;
    nd_uint8_t  neighbor_link_quality;
    nd_byte     res[2];
};

#define MAX_SMARTGW_SPEED    320000000

/**
 * Convert an encoded 1 byte transport value (5 bits mantissa, 3 bits exponent)
 * to an uplink/downlink speed value
 *
 * @param value the encoded 1 byte transport value
 * @return the uplink/downlink speed value (in kbit/s)
 */
static uint32_t deserialize_gw_speed(uint8_t value) {
  uint32_t speed;
  uint32_t exp;

  if (!value) {
    return 0;
  }

  if (value == UINT8_MAX) {
    /* maximum value: also return maximum value */
    return MAX_SMARTGW_SPEED;
  }

  speed = (value >> 3) + 1;
  exp = value & 7;

  while (exp != 0) {
    speed *= 10;
    exp--;
  }
  return speed;
}

/*
 * macro to convert the 8-bit mantissa/exponent to a double float
 * taken from olsr.org.
 */
#define VTIME_SCALE_FACTOR    0.0625
#define ME_TO_DOUBLE(me) \
  (double)(VTIME_SCALE_FACTOR*(1+(double)(me>>4)/16)*(double)(1<<(me&0x0F)))

/*
 * print a neighbor list with LQ extensions.
 */
static int
olsr_print_lq_neighbor4(netdissect_options *ndo,
                        const u_char *msg_data, u_int hello_len)
{
    const struct olsr_lq_neighbor4 *lq_neighbor;

    while (hello_len >= sizeof(struct olsr_lq_neighbor4)) {

        lq_neighbor = (const struct olsr_lq_neighbor4 *)msg_data;
        ND_TCHECK_SIZE(lq_neighbor);

        ND_PRINT("\n\t      neighbor %s, link-quality %.2f%%"
               ", neighbor-link-quality %.2f%%",
               GET_IPADDR_STRING(lq_neighbor->neighbor),
               ((double) GET_U_1(lq_neighbor->link_quality)/2.55),
               ((double) GET_U_1(lq_neighbor->neighbor_link_quality)/2.55));

        msg_data += sizeof(struct olsr_lq_neighbor4);
        hello_len -= sizeof(struct olsr_lq_neighbor4);
    }
    return (0);
trunc:
    return -1;
}

static int
olsr_print_lq_neighbor6(netdissect_options *ndo,
                        const u_char *msg_data, u_int hello_len)
{
    const struct olsr_lq_neighbor6 *lq_neighbor;

    while (hello_len >= sizeof(struct olsr_lq_neighbor6)) {

        lq_neighbor = (const struct olsr_lq_neighbor6 *)msg_data;
        ND_TCHECK_SIZE(lq_neighbor);

        ND_PRINT("\n\t      neighbor %s, link-quality %.2f%%"
               ", neighbor-link-quality %.2f%%",
               GET_IP6ADDR_STRING(lq_neighbor->neighbor),
               ((double) GET_U_1(lq_neighbor->link_quality)/2.55),
               ((double) GET_U_1(lq_neighbor->neighbor_link_quality)/2.55));

        msg_data += sizeof(struct olsr_lq_neighbor6);
        hello_len -= sizeof(struct olsr_lq_neighbor6);
    }
    return (0);
trunc:
    return -1;
}

/*
 * print a neighbor list.
 */
static int
olsr_print_neighbor(netdissect_options *ndo,
                    const u_char *msg_data, u_int hello_len)
{
    int neighbor;

    ND_PRINT("\n\t      neighbor\n\t\t");
    neighbor = 1;

    while (hello_len >= sizeof(nd_ipv4)) {
        /* print 4 neighbors per line */
        ND_PRINT("%s%s", GET_IPADDR_STRING(msg_data),
               neighbor % 4 == 0 ? "\n\t\t" : " ");

        msg_data += sizeof(nd_ipv4);
        hello_len -= sizeof(nd_ipv4);
    }
    return (0);
}


void
olsr_print(netdissect_options *ndo,
           const u_char *pptr, u_int length, int is_ipv6)
{
    union {
        const struct olsr_common *common;
        const struct olsr_msg4 *msg4;
        const struct olsr_msg6 *msg6;
        const struct olsr_hello *hello;
        const struct olsr_hello_link *hello_link;
        const struct olsr_tc *tc;
        const struct olsr_hna4 *hna;
    } ptr;

    u_int msg_type, msg_len, msg_tlen, hello_len;
    uint16_t name_entry_type, name_entry_len;
    u_int name_entry_padding;
    uint8_t link_type, neighbor_type;
    const u_char *tptr, *msg_data;

    ndo->ndo_protocol = "olsr";
    tptr = pptr;

    nd_print_protocol_caps(ndo);
    ND_PRINT("v%u", (is_ipv6) ? 6 : 4);

    if (length < sizeof(struct olsr_common)) {
        goto trunc;
    }

    ND_TCHECK_LEN(tptr, sizeof(struct olsr_common));

    ptr.common = (const struct olsr_common *)tptr;
    length = ND_MIN(length, GET_BE_U_2(ptr.common->packet_len));

    ND_PRINT(", seq 0x%04x, length %u",
            GET_BE_U_2(ptr.common->packet_seq),
            length);

    tptr += sizeof(struct olsr_common);

    /*
     * In non-verbose mode, just print version.
     */
    if (ndo->ndo_vflag < 1) {
        return;
    }

    while (tptr < (pptr+length)) {
        union
        {
            const struct olsr_msg4 *v4;
            const struct olsr_msg6 *v6;
        } msgptr;
        int msg_len_valid = 0;

        if (is_ipv6)
        {
            ND_TCHECK_LEN(tptr, sizeof(struct olsr_msg6));
            msgptr.v6 = (const struct olsr_msg6 *) tptr;
            msg_type = GET_U_1(msgptr.v6->msg_type);
            msg_len = GET_BE_U_2(msgptr.v6->msg_len);
            if ((msg_len >= sizeof (struct olsr_msg6))
                    && (msg_len <= length))
                msg_len_valid = 1;

            /* infinite loop check */
            if (msg_type == 0 || msg_len == 0) {
                return;
            }

            ND_PRINT("\n\t%s Message (%#04x), originator %s, ttl %u, hop %u"
                    "\n\t  vtime %.3fs, msg-seq 0x%04x, length %u%s",
                    tok2str(olsr_msg_values, "Unknown", msg_type),
                    msg_type, GET_IP6ADDR_STRING(msgptr.v6->originator),
                    GET_U_1(msgptr.v6->ttl),
                    GET_U_1(msgptr.v6->hopcount),
                    ME_TO_DOUBLE(GET_U_1(msgptr.v6->vtime)),
                    GET_BE_U_2(msgptr.v6->msg_seq),
                    msg_len, (msg_len_valid == 0) ? " (invalid)" : "");
            if (!msg_len_valid) {
                return;
            }

            msg_tlen = msg_len - sizeof(struct olsr_msg6);
            msg_data = tptr + sizeof(struct olsr_msg6);
        }
        else /* (!is_ipv6) */
        {
            ND_TCHECK_LEN(tptr, sizeof(struct olsr_msg4));
            msgptr.v4 = (const struct olsr_msg4 *) tptr;
            msg_type = GET_U_1(msgptr.v4->msg_type);
            msg_len = GET_BE_U_2(msgptr.v4->msg_len);
            if ((msg_len >= sizeof (struct olsr_msg4))
                    && (msg_len <= length))
                msg_len_valid = 1;

            /* infinite loop check */
            if (msg_type == 0 || msg_len == 0) {
                return;
            }

            ND_PRINT("\n\t%s Message (%#04x), originator %s, ttl %u, hop %u"
                    "\n\t  vtime %.3fs, msg-seq 0x%04x, length %u%s",
                    tok2str(olsr_msg_values, "Unknown", msg_type),
                    msg_type, GET_IPADDR_STRING(msgptr.v4->originator),
                    GET_U_1(msgptr.v4->ttl),
                    GET_U_1(msgptr.v4->hopcount),
                    ME_TO_DOUBLE(GET_U_1(msgptr.v4->vtime)),
                    GET_BE_U_2(msgptr.v4->msg_seq),
                    msg_len, (msg_len_valid == 0) ? " (invalid)" : "");
            if (!msg_len_valid) {
                return;
            }

            msg_tlen = msg_len - sizeof(struct olsr_msg4);
            msg_data = tptr + sizeof(struct olsr_msg4);
        }

        switch (msg_type) {
        case OLSR_HELLO_MSG:
        case OLSR_HELLO_LQ_MSG:
            if (msg_tlen < sizeof(struct olsr_hello))
                goto trunc;
            ND_TCHECK_LEN(msg_data, sizeof(struct olsr_hello));

            ptr.hello = (const struct olsr_hello *)msg_data;
            ND_PRINT("\n\t  hello-time %.3fs, MPR willingness %u",
                   ME_TO_DOUBLE(GET_U_1(ptr.hello->htime)),
                   GET_U_1(ptr.hello->will));
            msg_data += sizeof(struct olsr_hello);
            msg_tlen -= sizeof(struct olsr_hello);

            while (msg_tlen >= sizeof(struct olsr_hello_link)) {
                int hello_len_valid = 0;

                /*
                 * link-type.
                 */
                ND_TCHECK_LEN(msg_data, sizeof(struct olsr_hello_link));

                ptr.hello_link = (const struct olsr_hello_link *)msg_data;

                hello_len = GET_BE_U_2(ptr.hello_link->len);
                link_type = OLSR_EXTRACT_LINK_TYPE(GET_U_1(ptr.hello_link->link_code));
                neighbor_type = OLSR_EXTRACT_NEIGHBOR_TYPE(GET_U_1(ptr.hello_link->link_code));

                if ((hello_len <= msg_tlen)
                        && (hello_len >= sizeof(struct olsr_hello_link)))
                    hello_len_valid = 1;

                ND_PRINT("\n\t    link-type %s, neighbor-type %s, len %u%s",
                       tok2str(olsr_link_type_values, "Unknown", link_type),
                       tok2str(olsr_neighbor_type_values, "Unknown", neighbor_type),
                       hello_len,
                       (hello_len_valid == 0) ? " (invalid)" : "");

                if (hello_len_valid == 0)
                    break;

                msg_data += sizeof(struct olsr_hello_link);
                msg_tlen -= sizeof(struct olsr_hello_link);
                hello_len -= sizeof(struct olsr_hello_link);

                ND_TCHECK_LEN(msg_data, hello_len);
                if (msg_type == OLSR_HELLO_MSG) {
                    if (olsr_print_neighbor(ndo, msg_data, hello_len) == -1)
                        goto trunc;
                } else {
                    if (is_ipv6) {
                        if (olsr_print_lq_neighbor6(ndo, msg_data, hello_len) == -1)
                            goto trunc;
                    } else {
                        if (olsr_print_lq_neighbor4(ndo, msg_data, hello_len) == -1)
                            goto trunc;
                    }
                }

                msg_data += hello_len;
                msg_tlen -= hello_len;
            }
            break;

        case OLSR_TC_MSG:
        case OLSR_TC_LQ_MSG:
            if (msg_tlen < sizeof(struct olsr_tc))
                goto trunc;
            ND_TCHECK_LEN(msg_data, sizeof(struct olsr_tc));

            ptr.tc = (const struct olsr_tc *)msg_data;
            ND_PRINT("\n\t    advertised neighbor seq 0x%04x",
                   GET_BE_U_2(ptr.tc->ans_seq));
            msg_data += sizeof(struct olsr_tc);
            msg_tlen -= sizeof(struct olsr_tc);

            if (msg_type == OLSR_TC_MSG) {
                if (olsr_print_neighbor(ndo, msg_data, msg_tlen) == -1)
                    goto trunc;
            } else {
                if (is_ipv6) {
                    if (olsr_print_lq_neighbor6(ndo, msg_data, msg_tlen) == -1)
                        goto trunc;
                } else {
                    if (olsr_print_lq_neighbor4(ndo, msg_data, msg_tlen) == -1)
                        goto trunc;
                }
            }
            break;

        case OLSR_MID_MSG:
        {
            u_int addr_size = (u_int)sizeof(nd_ipv4);

            if (is_ipv6)
                addr_size = (u_int)sizeof(nd_ipv6);

            while (msg_tlen >= addr_size) {
                ND_TCHECK_LEN(msg_data, addr_size);
                ND_PRINT("\n\t  interface address %s",
                        is_ipv6 ? GET_IP6ADDR_STRING(msg_data) :
                        GET_IPADDR_STRING(msg_data));

                msg_data += addr_size;
                msg_tlen -= addr_size;
            }
            break;
        }

        case OLSR_HNA_MSG:
            if (is_ipv6)
            {
                int i = 0;

                ND_PRINT("\n\t  Advertised networks (total %u)",
                        (unsigned int) (msg_tlen / sizeof(struct olsr_hna6)));

                while (msg_tlen >= sizeof(struct olsr_hna6)) {
                    const struct olsr_hna6 *hna6;

                    ND_TCHECK_LEN(msg_data, sizeof(struct olsr_hna6));

                    hna6 = (const struct olsr_hna6 *)msg_data;

                    ND_PRINT("\n\t    #%i: %s/%u",
                            i, GET_IP6ADDR_STRING(hna6->network),
                            mask62plen (hna6->mask));

                    msg_data += sizeof(struct olsr_hna6);
                    msg_tlen -= sizeof(struct olsr_hna6);
                }
            }
            else
            {
                int col = 0;

                ND_PRINT("\n\t  Advertised networks (total %u)",
                        (unsigned int) (msg_tlen / sizeof(struct olsr_hna4)));

                while (msg_tlen >= sizeof(struct olsr_hna4)) {
                    ND_TCHECK_LEN(msg_data, sizeof(struct olsr_hna4));

                    ptr.hna = (const struct olsr_hna4 *)msg_data;

                    /* print 4 prefixes per line */
                    if (!ptr.hna->network[0] && !ptr.hna->network[1] &&
                        !ptr.hna->network[2] && !ptr.hna->network[3] &&
                        !ptr.hna->mask[GW_HNA_PAD] &&
                        ptr.hna->mask[GW_HNA_FLAGS]) {
                            /* smart gateway */
                            ND_PRINT("%sSmart-Gateway:%s%s%s%s%s %u/%u",
                                col == 0 ? "\n\t    " : ", ", /* indent */
                                /* sgw */
                                /* LINKSPEED */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_LINKSPEED) ? " LINKSPEED" : "",
                                /* IPV4 */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_IPV4) ? " IPV4" : "",
                                /* IPV4-NAT */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_IPV4_NAT) ? " IPV4-NAT" : "",
                                /* IPV6 */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_IPV6) ? " IPV6" : "",
                                /* IPv6PREFIX */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_IPV6PREFIX) ? " IPv6-PREFIX" : "",
                                /* uplink */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_LINKSPEED) ?
                                 deserialize_gw_speed(ptr.hna->mask[GW_HNA_UPLINK]) : 0,
                                /* downlink */
                                (ptr.hna->mask[GW_HNA_FLAGS] &
                                 GW_HNA_FLAG_LINKSPEED) ?
                                 deserialize_gw_speed(ptr.hna->mask[GW_HNA_DOWNLINK]) : 0
                                );
                    } else {
                        /* normal route */
                        ND_PRINT("%s%s/%u",
                                col == 0 ? "\n\t    " : ", ",
                                GET_IPADDR_STRING(ptr.hna->network),
                                mask2plen(GET_BE_U_4(ptr.hna->mask)));
                    }

                    msg_data += sizeof(struct olsr_hna4);
                    msg_tlen -= sizeof(struct olsr_hna4);

                    col = (col + 1) % 4;
                }
            }
            break;

        case OLSR_NAMESERVICE_MSG:
        {
            u_int name_entries;
            u_int addr_size;
            int name_entries_valid;
            u_int i;

            if (msg_tlen < 4)
                goto trunc;

            name_entries = GET_BE_U_2(msg_data + 2);
            addr_size = 4;
            if (is_ipv6)
                addr_size = 16;

            name_entries_valid = 0;
            if ((name_entries > 0)
                    && ((name_entries * (4 + addr_size)) <= msg_tlen))
                name_entries_valid = 1;

            ND_PRINT("\n\t  Version %u, Entries %u%s",
                   GET_BE_U_2(msg_data),
                   name_entries, (name_entries_valid == 0) ? " (invalid)" : "");

            if (name_entries_valid == 0)
                break;

            msg_data += 4;
            msg_tlen -= 4;

            for (i = 0; i < name_entries; i++) {
                int name_entry_len_valid = 0;

                if (msg_tlen < 4)
                    break;

                name_entry_type = GET_BE_U_2(msg_data);
                name_entry_len = GET_BE_U_2(msg_data + 2);

                msg_data += 4;
                msg_tlen -= 4;

                if ((name_entry_len > 0) && ((addr_size + name_entry_len) <= msg_tlen))
                    name_entry_len_valid = 1;

                ND_PRINT("\n\t    #%u: type %#06x, length %u%s",
                        (unsigned int) i, name_entry_type,
                        name_entry_len, (name_entry_len_valid == 0) ? " (invalid)" : "");

                if (name_entry_len_valid == 0)
                    break;

                /* 32-bit alignment */
                name_entry_padding = 0;
                if (name_entry_len%4 != 0)
                    name_entry_padding = 4-(name_entry_len%4);

                if (msg_tlen < addr_size + name_entry_len + name_entry_padding)
                    goto trunc;

                ND_TCHECK_LEN(msg_data,
                              addr_size + name_entry_len + name_entry_padding);

                if (is_ipv6)
                    ND_PRINT(", address %s, name \"",
                            GET_IP6ADDR_STRING(msg_data));
                else
                    ND_PRINT(", address %s, name \"",
                            GET_IPADDR_STRING(msg_data));
                (void)nd_printn(ndo, msg_data + addr_size, name_entry_len, NULL);
                ND_PRINT("\"");

                msg_data += addr_size + name_entry_len + name_entry_padding;
                msg_tlen -= addr_size + name_entry_len + name_entry_padding;
            } /* for (i = 0; i < name_entries; i++) */
            break;
        } /* case OLSR_NAMESERVICE_MSG */

            /*
             * FIXME those are the defined messages that lack a decoder
             * you are welcome to contribute code ;-)
             */
        case OLSR_POWERINFO_MSG:
        default:
            print_unknown_data(ndo, msg_data, "\n\t    ", msg_tlen);
            break;
        } /* switch (msg_type) */
        tptr += msg_len;
    } /* while (tptr < (pptr+length)) */

    return;

 trunc:
    nd_print_trunc(ndo);
}