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/*
 * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994, 1995, 1996
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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, (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, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * 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.
 */

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

#include <tcpdump-stdinc.h>

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

#include "interface.h"
#include "addrtoname.h"
#include "extract.h"                    /* must come after interface.h */

#include "ip.h"
#include "udp.h"
#include "ipproto.h"
#include "mpls.h"

/*
 * Interface Control Message Protocol Definitions.
 * Per RFC 792, September 1981.
 */

/*
 * Structure of an icmp header.
 */
struct icmp {
        uint8_t  icmp_type;             /* type of message, see below */
        uint8_t  icmp_code;             /* type sub code */
        uint16_t icmp_cksum;            /* ones complement cksum of struct */
        union {
                uint8_t ih_pptr;                        /* ICMP_PARAMPROB */
                struct in_addr ih_gwaddr;       /* ICMP_REDIRECT */
                struct ih_idseq {
                        uint16_t icd_id;
                        uint16_t icd_seq;
                } ih_idseq;
                uint32_t ih_void;
        } icmp_hun;
#define icmp_pptr       icmp_hun.ih_pptr
#define icmp_gwaddr     icmp_hun.ih_gwaddr
#define icmp_id         icmp_hun.ih_idseq.icd_id
#define icmp_seq        icmp_hun.ih_idseq.icd_seq
#define icmp_void       icmp_hun.ih_void
        union {
                struct id_ts {
                        uint32_t its_otime;
                        uint32_t its_rtime;
                        uint32_t its_ttime;
                } id_ts;
                struct id_ip  {
                        struct ip idi_ip;
                        /* options and then 64 bits of data */
                } id_ip;
                uint32_t id_mask;
                uint8_t id_data[1];
        } icmp_dun;
#define icmp_otime      icmp_dun.id_ts.its_otime
#define icmp_rtime      icmp_dun.id_ts.its_rtime
#define icmp_ttime      icmp_dun.id_ts.its_ttime
#define icmp_ip         icmp_dun.id_ip.idi_ip
#define icmp_mask       icmp_dun.id_mask
#define icmp_data       icmp_dun.id_data
};

#define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4)
#define ICMP_MPLS_EXT_VERSION 2

/*
 * Lower bounds on packet lengths for various types.
 * For the error advice packets must first insure that the
 * packet is large enought to contain the returned ip header.
 * Only then can we do the check to see if 64 bits of packet
 * data have been returned, since we need to check the returned
 * ip header length.
 */
#define ICMP_MINLEN     8                               /* abs minimum */
#define ICMP_EXTD_MINLEN (156 - sizeof (struct ip))     /* draft-bonica-internet-icmp-08 */
#define ICMP_TSLEN      (8 + 3 * sizeof (uint32_t))     /* timestamp */
#define ICMP_MASKLEN    12                              /* address mask */
#define ICMP_ADVLENMIN  (8 + sizeof (struct ip) + 8)    /* min */
#define ICMP_ADVLEN(p)  (8 + (IP_HL(&(p)->icmp_ip) << 2) + 8)
        /* N.B.: must separately check that ip_hl >= 5 */

/*
 * Definition of type and code field values.
 */
#define ICMP_ECHOREPLY          0                /* echo reply */
#define ICMP_UNREACH            3               /* dest unreachable, codes: */
#define         ICMP_UNREACH_NET        0                /* bad net */
#define         ICMP_UNREACH_HOST       1               /* bad host */
#define         ICMP_UNREACH_PROTOCOL   2               /* bad protocol */
#define         ICMP_UNREACH_PORT       3               /* bad port */
#define         ICMP_UNREACH_NEEDFRAG   4               /* IP_DF caused drop */
#define         ICMP_UNREACH_SRCFAIL    5               /* src route failed */
#define         ICMP_UNREACH_NET_UNKNOWN 6              /* unknown net */
#define         ICMP_UNREACH_HOST_UNKNOWN 7             /* unknown host */
#define         ICMP_UNREACH_ISOLATED   8               /* src host isolated */
#define         ICMP_UNREACH_NET_PROHIB 9               /* prohibited access */
#define         ICMP_UNREACH_HOST_PROHIB 10             /* ditto */
#define         ICMP_UNREACH_TOSNET     11              /* bad tos for net */
#define         ICMP_UNREACH_TOSHOST    12              /* bad tos for host */
#define ICMP_SOURCEQUENCH       4               /* packet lost, slow down */
#define ICMP_REDIRECT           5               /* shorter route, codes: */
#define         ICMP_REDIRECT_NET       0                /* for network */
#define         ICMP_REDIRECT_HOST      1               /* for host */
#define         ICMP_REDIRECT_TOSNET    2               /* for tos and net */
#define         ICMP_REDIRECT_TOSHOST   3               /* for tos and host */
#define ICMP_ECHO               8               /* echo service */
#define ICMP_ROUTERADVERT       9               /* router advertisement */
#define ICMP_ROUTERSOLICIT      10              /* router solicitation */
#define ICMP_TIMXCEED           11              /* time exceeded, code: */
#define         ICMP_TIMXCEED_INTRANS   0                /* ttl==0 in transit */
#define         ICMP_TIMXCEED_REASS     1               /* ttl==0 in reass */
#define ICMP_PARAMPROB          12              /* ip header bad */
#define         ICMP_PARAMPROB_OPTABSENT 1              /* req. opt. absent */
#define ICMP_TSTAMP             13              /* timestamp request */
#define ICMP_TSTAMPREPLY        14              /* timestamp reply */
#define ICMP_IREQ               15              /* information request */
#define ICMP_IREQREPLY          16              /* information reply */
#define ICMP_MASKREQ            17              /* address mask request */
#define ICMP_MASKREPLY          18              /* address mask reply */

#define ICMP_MAXTYPE            18

#define ICMP_ERRTYPE(type) \
        ((type) == ICMP_UNREACH || (type) == ICMP_SOURCEQUENCH || \
        (type) == ICMP_REDIRECT || (type) == ICMP_TIMXCEED || \
        (type) == ICMP_PARAMPROB)
#define ICMP_MPLS_EXT_TYPE(type) \
        ((type) == ICMP_UNREACH || \
         (type) == ICMP_TIMXCEED || \
         (type) == ICMP_PARAMPROB)
/* rfc1700 */
#ifndef ICMP_UNREACH_NET_UNKNOWN
#define ICMP_UNREACH_NET_UNKNOWN        6       /* destination net unknown */
#endif
#ifndef ICMP_UNREACH_HOST_UNKNOWN
#define ICMP_UNREACH_HOST_UNKNOWN       7       /* destination host unknown */
#endif
#ifndef ICMP_UNREACH_ISOLATED
#define ICMP_UNREACH_ISOLATED           8       /* source host isolated */
#endif
#ifndef ICMP_UNREACH_NET_PROHIB
#define ICMP_UNREACH_NET_PROHIB         9       /* admin prohibited net */
#endif
#ifndef ICMP_UNREACH_HOST_PROHIB
#define ICMP_UNREACH_HOST_PROHIB        10      /* admin prohibited host */
#endif
#ifndef ICMP_UNREACH_TOSNET
#define ICMP_UNREACH_TOSNET             11      /* tos prohibited net */
#endif
#ifndef ICMP_UNREACH_TOSHOST
#define ICMP_UNREACH_TOSHOST            12      /* tos prohibited host */
#endif

/* rfc1716 */
#ifndef ICMP_UNREACH_FILTER_PROHIB
#define ICMP_UNREACH_FILTER_PROHIB      13      /* admin prohibited filter */
#endif
#ifndef ICMP_UNREACH_HOST_PRECEDENCE
#define ICMP_UNREACH_HOST_PRECEDENCE    14      /* host precedence violation */
#endif
#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
#define ICMP_UNREACH_PRECEDENCE_CUTOFF  15      /* precedence cutoff */
#endif

/* Most of the icmp types */
static const struct tok icmp2str[] = {
        { ICMP_ECHOREPLY,               "echo reply" },
        { ICMP_SOURCEQUENCH,            "source quench" },
        { ICMP_ECHO,                    "echo request" },
        { ICMP_ROUTERSOLICIT,           "router solicitation" },
        { ICMP_TSTAMP,                  "time stamp request" },
        { ICMP_TSTAMPREPLY,             "time stamp reply" },
        { ICMP_IREQ,                    "information request" },
        { ICMP_IREQREPLY,               "information reply" },
        { ICMP_MASKREQ,                 "address mask request" },
        { 0,                            NULL }
};

/* Formats for most of the ICMP_UNREACH codes */
static const struct tok unreach2str[] = {
        { ICMP_UNREACH_NET,             "net %s unreachable" },
        { ICMP_UNREACH_HOST,            "host %s unreachable" },
        { ICMP_UNREACH_SRCFAIL,
            "%s unreachable - source route failed" },
        { ICMP_UNREACH_NET_UNKNOWN,     "net %s unreachable - unknown" },
        { ICMP_UNREACH_HOST_UNKNOWN,    "host %s unreachable - unknown" },
        { ICMP_UNREACH_ISOLATED,
            "%s unreachable - source host isolated" },
        { ICMP_UNREACH_NET_PROHIB,
            "net %s unreachable - admin prohibited" },
        { ICMP_UNREACH_HOST_PROHIB,
            "host %s unreachable - admin prohibited" },
        { ICMP_UNREACH_TOSNET,
            "net %s unreachable - tos prohibited" },
        { ICMP_UNREACH_TOSHOST,
            "host %s unreachable - tos prohibited" },
        { ICMP_UNREACH_FILTER_PROHIB,
            "host %s unreachable - admin prohibited filter" },
        { ICMP_UNREACH_HOST_PRECEDENCE,
            "host %s unreachable - host precedence violation" },
        { ICMP_UNREACH_PRECEDENCE_CUTOFF,
            "host %s unreachable - precedence cutoff" },
        { 0,                            NULL }
};

/* Formats for the ICMP_REDIRECT codes */
static const struct tok type2str[] = {
        { ICMP_REDIRECT_NET,            "redirect %s to net %s" },
        { ICMP_REDIRECT_HOST,           "redirect %s to host %s" },
        { ICMP_REDIRECT_TOSNET,         "redirect-tos %s to net %s" },
        { ICMP_REDIRECT_TOSHOST,        "redirect-tos %s to host %s" },
        { 0,                            NULL }
};

/* rfc1191 */
struct mtu_discovery {
        uint16_t unused;
        uint16_t nexthopmtu;
};

/* rfc1256 */
struct ih_rdiscovery {
        uint8_t ird_addrnum;
        uint8_t ird_addrsiz;
        uint16_t ird_lifetime;
};

struct id_rdiscovery {
        uint32_t ird_addr;
        uint32_t ird_pref;
};

/*
 * draft-bonica-internet-icmp-08
 *
 * The Destination Unreachable, Time Exceeded
 * and Parameter Problem messages are slighly changed as per
 * the above draft. A new Length field gets added to give
 * the caller an idea about the length of the piggypacked
 * IP packet before the MPLS extension header starts.
 *
 * The Length field represents length of the padded "original datagram"
 * field  measured in 32-bit words.
 *
 * 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |     Code      |          Checksum             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     unused    |    Length     |          unused               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |      Internet Header + leading octets of original datagram    |
 * |                                                               |
 * |                           //                                  |
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct icmp_ext_t {
    uint8_t icmp_type;
    uint8_t icmp_code;
    uint8_t icmp_checksum[2];
    uint8_t icmp_reserved;
    uint8_t icmp_length;
    uint8_t icmp_reserved2[2];
    uint8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */
    uint8_t icmp_ext_version_res[2];
    uint8_t icmp_ext_checksum[2];
    uint8_t icmp_ext_data[1];
};

struct icmp_mpls_ext_object_header_t {
    uint8_t length[2];
    uint8_t class_num;
    uint8_t ctype;
};

static const struct tok icmp_mpls_ext_obj_values[] = {
    { 1, "MPLS Stack Entry" },
    { 2, "Extended Payload" },
    { 0, NULL}
};

/* prototypes */
const char *icmp_tstamp_print(u_int);

/* print the milliseconds since midnight UTC */
const char *
icmp_tstamp_print(u_int tstamp)
{
    u_int msec,sec,min,hrs;

    static char buf[64];

    msec = tstamp % 1000;
    sec = tstamp / 1000;
    min = sec / 60; sec -= min * 60;
    hrs = min / 60; min -= hrs * 60;
    snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec);
    return buf;
}

void
icmp_print(netdissect_options *ndo, const u_char *bp, u_int plen, const u_char *bp2,
           int fragmented)
{
        char *cp;
        const struct icmp *dp;
        const struct icmp_ext_t *ext_dp;
        const struct ip *ip;
        const char *str, *fmt;
        const struct ip *oip;
        const struct udphdr *ouh;
        const uint8_t *obj_tptr;
        uint32_t raw_label;
        const u_char *snapend_save;
        const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header;
        u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype;
        char buf[MAXHOSTNAMELEN + 100];
        struct cksum_vec vec[1];

        dp = (struct icmp *)bp;
        ext_dp = (struct icmp_ext_t *)bp;
        ip = (struct ip *)bp2;
        str = buf;

        ND_TCHECK(dp->icmp_code);
        switch (dp->icmp_type) {

        case ICMP_ECHO:
        case ICMP_ECHOREPLY:
                ND_TCHECK(dp->icmp_seq);
                (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u",
                               dp->icmp_type == ICMP_ECHO ?
                               "request" : "reply",
                               EXTRACT_16BITS(&dp->icmp_id),
                               EXTRACT_16BITS(&dp->icmp_seq));
                break;

        case ICMP_UNREACH:
                ND_TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {

                case ICMP_UNREACH_PROTOCOL:
                        ND_TCHECK(dp->icmp_ip.ip_p);
                        (void)snprintf(buf, sizeof(buf),
                            "%s protocol %d unreachable",
                            ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
                            dp->icmp_ip.ip_p);
                        break;

                case ICMP_UNREACH_PORT:
                        ND_TCHECK(dp->icmp_ip.ip_p);
                        oip = &dp->icmp_ip;
                        hlen = IP_HL(oip) * 4;
                        ouh = (struct udphdr *)(((u_char *)oip) + hlen);
                        ND_TCHECK(ouh->uh_dport);
                        dport = EXTRACT_16BITS(&ouh->uh_dport);
                        switch (oip->ip_p) {

                        case IPPROTO_TCP:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s tcp port %s unreachable",
                                        ipaddr_string(ndo, &oip->ip_dst),
                                        tcpport_string(dport));
                                break;

                        case IPPROTO_UDP:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s udp port %s unreachable",
                                        ipaddr_string(ndo, &oip->ip_dst),
                                        udpport_string(dport));
                                break;

                        default:
                                (void)snprintf(buf, sizeof(buf),
                                        "%s protocol %d port %d unreachable",
                                        ipaddr_string(ndo, &oip->ip_dst),
                                        oip->ip_p, dport);
                                break;
                        }
                        break;

                case ICMP_UNREACH_NEEDFRAG:
                    {
                        register const struct mtu_discovery *mp;
                        mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void;
                        mtu = EXTRACT_16BITS(&mp->nexthopmtu);
                        if (mtu) {
                                (void)snprintf(buf, sizeof(buf),
                                    "%s unreachable - need to frag (mtu %d)",
                                    ipaddr_string(ndo, &dp->icmp_ip.ip_dst), mtu);
                        } else {
                                (void)snprintf(buf, sizeof(buf),
                                    "%s unreachable - need to frag",
                                    ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
                        }
                    }
                        break;

                default:
                        fmt = tok2str(unreach2str, "#%d %%s unreachable",
                            dp->icmp_code);
                        (void)snprintf(buf, sizeof(buf), fmt,
                            ipaddr_string(ndo, &dp->icmp_ip.ip_dst));
                        break;
                }
                break;

        case ICMP_REDIRECT:
                ND_TCHECK(dp->icmp_ip.ip_dst);
                fmt = tok2str(type2str, "redirect-#%d %%s to net %%s",
                    dp->icmp_code);
                (void)snprintf(buf, sizeof(buf), fmt,
                    ipaddr_string(ndo, &dp->icmp_ip.ip_dst),
                    ipaddr_string(ndo, &dp->icmp_gwaddr));
                break;

        case ICMP_ROUTERADVERT:
            {
                register const struct ih_rdiscovery *ihp;
                register const struct id_rdiscovery *idp;
                u_int lifetime, num, size;

                (void)snprintf(buf, sizeof(buf), "router advertisement");
                cp = buf + strlen(buf);

                ihp = (struct ih_rdiscovery *)&dp->icmp_void;
                ND_TCHECK(*ihp);
                (void)strncpy(cp, " lifetime ", sizeof(buf) - (cp - buf));
                cp = buf + strlen(buf);
                lifetime = EXTRACT_16BITS(&ihp->ird_lifetime);
                if (lifetime < 60) {
                        (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u",
                            lifetime);
                } else if (lifetime < 60 * 60) {
                        (void)snprintf(cp, sizeof(buf) - (cp - buf), "%u:%02u",
                            lifetime / 60, lifetime % 60);
                } else {
                        (void)snprintf(cp, sizeof(buf) - (cp - buf),
                            "%u:%02u:%02u",
                            lifetime / 3600,
                            (lifetime % 3600) / 60,
                            lifetime % 60);
                }
                cp = buf + strlen(buf);

                num = ihp->ird_addrnum;
                (void)snprintf(cp, sizeof(buf) - (cp - buf), " %d:", num);
                cp = buf + strlen(buf);

                size = ihp->ird_addrsiz;
                if (size != 2) {
                        (void)snprintf(cp, sizeof(buf) - (cp - buf),
                            " [size %d]", size);
                        break;
                }
                idp = (struct id_rdiscovery *)&dp->icmp_data;
                while (num-- > 0) {
                        ND_TCHECK(*idp);
                        (void)snprintf(cp, sizeof(buf) - (cp - buf), " {%s %u}",
                            ipaddr_string(ndo, &idp->ird_addr),
                            EXTRACT_32BITS(&idp->ird_pref));
                        cp = buf + strlen(buf);
                        ++idp;
                }
            }
                break;

        case ICMP_TIMXCEED:
                ND_TCHECK(dp->icmp_ip.ip_dst);
                switch (dp->icmp_code) {

                case ICMP_TIMXCEED_INTRANS:
                        str = "time exceeded in-transit";
                        break;

                case ICMP_TIMXCEED_REASS:
                        str = "ip reassembly time exceeded";
                        break;

                default:
                        (void)snprintf(buf, sizeof(buf), "time exceeded-#%d",
                            dp->icmp_code);
                        break;
                }
                break;

        case ICMP_PARAMPROB:
                if (dp->icmp_code)
                        (void)snprintf(buf, sizeof(buf),
                            "parameter problem - code %d", dp->icmp_code);
                else {
                        ND_TCHECK(dp->icmp_pptr);
                        (void)snprintf(buf, sizeof(buf),
                            "parameter problem - octet %d", dp->icmp_pptr);
                }
                break;

        case ICMP_MASKREPLY:
                ND_TCHECK(dp->icmp_mask);
                (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x",
                    EXTRACT_32BITS(&dp->icmp_mask));
                break;

        case ICMP_TSTAMP:
                ND_TCHECK(dp->icmp_seq);
                (void)snprintf(buf, sizeof(buf),
                    "time stamp query id %u seq %u",
                    EXTRACT_16BITS(&dp->icmp_id),
                    EXTRACT_16BITS(&dp->icmp_seq));
                break;

        case ICMP_TSTAMPREPLY:
                ND_TCHECK(dp->icmp_ttime);
                (void)snprintf(buf, sizeof(buf),
                    "time stamp reply id %u seq %u: org %s",
                               EXTRACT_16BITS(&dp->icmp_id),
                               EXTRACT_16BITS(&dp->icmp_seq),
                               icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime)));

                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s",
                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime)));
                (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s",
                         icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime)));
                break;

        default:
                str = tok2str(icmp2str, "type-#%d", dp->icmp_type);
                break;
        }
        ND_PRINT((ndo, "ICMP %s, length %u", str, plen));
        if (ndo->ndo_vflag && !fragmented) { /* don't attempt checksumming if this is a frag */
                uint16_t sum, icmp_sum;
                struct cksum_vec vec[1];
                if (ND_TTEST2(*bp, plen)) {
                        vec[0].ptr = (const uint8_t *)(void *)dp;
                        vec[0].len = plen;
                        sum = in_cksum(vec, 1);
                        if (sum != 0) {
                                icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum);
                                ND_PRINT((ndo, " (wrong icmp cksum %x (->%x)!)",
                                             icmp_sum,
                                             in_cksum_shouldbe(icmp_sum, sum)));
                        }
                }
        }

        /*
         * print the remnants of the IP packet.
         * save the snaplength as this may get overidden in the IP printer.
         */
        if (ndo->ndo_vflag >= 1 && ICMP_ERRTYPE(dp->icmp_type)) {
                bp += 8;
                ND_PRINT((ndo, "\n\t"));
                ip = (struct ip *)bp;
                ndo->ndo_snaplen = ndo->ndo_snapend - bp;
                snapend_save = ndo->ndo_snapend;
                ip_print(ndo, bp, EXTRACT_16BITS(&ip->ip_len));
                ndo->ndo_snapend = snapend_save;
        }

        /*
         * Attempt to decode the MPLS extensions only for some ICMP types.
         */
        if (ndo->ndo_vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) {

            ND_TCHECK(*ext_dp);

            /*
             * Check first if the mpls extension header shows a non-zero length.
             * If the length field is not set then silently verify the checksum
             * to check if an extension header is present. This is expedient,
             * however not all implementations set the length field proper.
             */
            if (!ext_dp->icmp_length) {
                vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
                vec[0].len = plen - ICMP_EXTD_MINLEN;
                if (in_cksum(vec, 1)) {
                    return;
                }
            }

            ND_PRINT((ndo, "\n\tMPLS extension v%u",
                   ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))));

            /*
             * Sanity checking of the header.
             */
            if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) !=
                ICMP_MPLS_EXT_VERSION) {
                ND_PRINT((ndo, " packet not supported"));
                return;
            }

            hlen = plen - ICMP_EXTD_MINLEN;
            vec[0].ptr = (const uint8_t *)(void *)&ext_dp->icmp_ext_version_res;
            vec[0].len = hlen;
            ND_PRINT((ndo, ", checksum 0x%04x (%scorrect), length %u",
                   EXTRACT_16BITS(ext_dp->icmp_ext_checksum),
                   in_cksum(vec, 1) ? "in" : "",
                   hlen));

            hlen -= 4; /* subtract common header size */
            obj_tptr = (uint8_t *)ext_dp->icmp_ext_data;

            while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) {

                icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr;
                ND_TCHECK(*icmp_mpls_ext_object_header);
                obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length);
                obj_class_num = icmp_mpls_ext_object_header->class_num;
                obj_ctype = icmp_mpls_ext_object_header->ctype;
                obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t);

                ND_PRINT((ndo, "\n\t  %s Object (%u), Class-Type: %u, length %u",
                       tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num),
                       obj_class_num,
                       obj_ctype,
                       obj_tlen));

                hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */

                /* infinite loop protection */
                if ((obj_class_num == 0) ||
                    (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) {
                    return;
                }
                obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t);

                switch (obj_class_num) {
                case 1:
                    switch(obj_ctype) {
                    case 1:
                        ND_TCHECK2(*obj_tptr, 4);
                        raw_label = EXTRACT_32BITS(obj_tptr);
                        ND_PRINT((ndo, "\n\t    label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)));
                        if (MPLS_STACK(raw_label))
                            ND_PRINT((ndo, ", [S]"));
                        ND_PRINT((ndo, ", ttl %u", MPLS_TTL(raw_label)));
                        break;
                    default:
                        print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
                    }
                    break;

               /*
                *  FIXME those are the defined objects that lack a decoder
                *  you are welcome to contribute code ;-)
                */
                case 2:
                default:
                    print_unknown_data(ndo, obj_tptr, "\n\t    ", obj_tlen);
                    break;
                }
                if (hlen < obj_tlen)
                    break;
                hlen -= obj_tlen;
                obj_tptr += obj_tlen;
            }
        }

        return;
trunc:
        ND_PRINT((ndo, "[|icmp]"));
}
/*
 * Local Variables:
 * c-style: whitesmith
 * c-basic-offset: 8
 * End:
 */