usr.sbin/snoop/snoop_ppp.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2001-2002 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysmacros.h>
#include <net/ppp_defs.h>
#include <net/ppp-comp.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <arpa/inet.h>
#include "snoop.h"
#include "snoop_ppp.h"

static int interpret_ppp_cp(int, uchar_t *, int, ppp_protoinfo_t *);
static int interpret_cp_options(uchar_t *, int, ppp_protoinfo_t *);
static int interpret_ppp_chap(int, uchar_t *, int, ppp_protoinfo_t *);
static int interpret_ppp_pap(int, uchar_t *, int, ppp_protoinfo_t *);
static int interpret_ppp_lqr(int, uchar_t *, int, ppp_protoinfo_t *);
static ppp_protoinfo_t *ppp_getprotoinfo(uint16_t);
static cp_optinfo_t *ppp_getoptinfo(cp_optinfo_t *, uint16_t);
static optformat_func_t opt_format_vendor;
static optformat_func_t opt_format_mru;
static optformat_func_t opt_format_accm;
static optformat_func_t opt_format_authproto;
static optformat_func_t opt_format_qualproto;
static optformat_func_t opt_format_magicnum;
static optformat_func_t opt_format_fcs;
static optformat_func_t opt_format_sdp;
static optformat_func_t opt_format_nummode;
static optformat_func_t opt_format_callback;
static optformat_func_t opt_format_mrru;
static optformat_func_t opt_format_epdisc;
static optformat_func_t opt_format_dce;
static optformat_func_t opt_format_linkdisc;
static optformat_func_t opt_format_i18n;
static optformat_func_t opt_format_ipaddresses;
static optformat_func_t opt_format_ipcompproto;
static optformat_func_t opt_format_ipaddress;
static optformat_func_t opt_format_mobileipv4;
static optformat_func_t opt_format_ifaceid;
static optformat_func_t opt_format_ipv6compproto;
static optformat_func_t opt_format_compoui;
static optformat_func_t opt_format_bsdcomp;
static optformat_func_t opt_format_staclzs;
static optformat_func_t opt_format_mppc;
static optformat_func_t opt_format_gandalf;
static optformat_func_t opt_format_lzsdcp;
static optformat_func_t opt_format_magnalink;
static optformat_func_t opt_format_deflate;
static optformat_func_t opt_format_encroui;
static optformat_func_t opt_format_dese;
static optformat_func_t opt_format_muxpid;

/*
 * Many strings below are initialized with "Unknown".
 */
static char unknown_string[] = "Unknown";

/*
 * Each known PPP protocol has an associated ppp_protoinfo_t in this array.
 * Even if we can't decode the protocol (interpret_proto() == NULL),
 * interpret_ppp() will at least print the protocol's name.  There is no
 * dependency on the ordering of the entries in this array.  They have been
 * ordered such that the most commonly used protocols are near the front.
 * The array is delimited by a last entry of protocol of type
 * PPP_PROTO_UNKNOWN.
 */
static ppp_protoinfo_t protoinfo_array[] = {
    { PPP_IP,   "IP",       interpret_ip,   NULL,   NULL },
    { PPP_IPV6, "IPv6",     interpret_ipv6, NULL,   NULL },
    { PPP_COMP, "Compressed Data",  NULL,   NULL,   NULL },
    { PPP_OSI,  "OSI",          NULL,   NULL,   NULL },
    { PPP_AT,   "AppleTalk",        NULL,   NULL,   NULL },
    { PPP_IPX,  "IPX",          NULL,   NULL,   NULL },
    { PPP_VJC_COMP, "VJ Compressed TCP",    NULL,   NULL,   NULL },
    { PPP_VJC_UNCOMP, "VJ Uncompressed TCP", NULL,  NULL,   NULL },
    { PPP_BRIDGE,   "Bridging",     NULL,   NULL,   NULL },
    { PPP_802HELLO, "802.1d Hello",     NULL,   NULL,   NULL },
    { PPP_MP,   "MP",           NULL,   NULL,   NULL },
    { PPP_ENCRYPT,  "Encryption",       NULL,   NULL,   NULL },
    { PPP_ENCRYPTFRAG, "Individual Link Encryption", NULL,  NULL,   NULL },
    { PPP_MUX,  "PPP Muxing",       NULL,   NULL,   NULL },
    { PPP_COMPFRAG, "Single Link Compressed Data",  NULL,   NULL,   NULL },
    { PPP_FULLHDR,  "IP Compression",   NULL,   NULL,   NULL },
    { PPP_COMPTCP,  "IP Compression",   NULL,   NULL,   NULL },
    { PPP_COMPNONTCP, "IP Compression", NULL,   NULL,   NULL },
    { PPP_COMPUDP8, "IP Compression",   NULL,   NULL,   NULL },
    { PPP_COMPRTP8, "IP Compression",   NULL,   NULL,   NULL },
    { PPP_COMPTCPND, "IP Compression",  NULL,   NULL,   NULL },
    { PPP_COMPSTATE, "IP Compression",  NULL,   NULL,   NULL },
    { PPP_COMPUDP16, "IP Compression",  NULL,   NULL,   NULL },
    { PPP_COMPRTP16, "IP Compression",  NULL,   NULL,   NULL },
    { PPP_MPLS, "MPLS",         NULL,   NULL,   NULL },
    { PPP_MPLSMC,   "MPLS M/C",     NULL,   NULL,   NULL },
    { PPP_LQR,  "LQR",      interpret_ppp_lqr,  "PPP-LQR:  ",
        "Link Quality Report" },
    { PPP_LCP,  "LCP",      interpret_ppp_cp,   "PPP-LCP:  ",
        "Link Control Protocol" },
    { PPP_IPCP, "IPCP",     interpret_ppp_cp,   "PPP-IPCP: ",
        "IP Control Protocol" },
    { PPP_IPV6CP,   "IPV6CP",   interpret_ppp_cp,   "PPP-IPV6CP:  ",
        "IPv6 Control Protocol" },
    { PPP_CCP,  "CCP",      interpret_ppp_cp,   "PPP-CCP:  ",
        "Compression Control Protocol" },
    { PPP_CCPFRAG,  "CCP-Link", interpret_ppp_cp, "PPP-CCP-Link:  ",
        "Per-Link Compression Control Protocol" },
    { PPP_ECP,  "ECP",      interpret_ppp_cp,   "PPP-ECP:  ",
        "Encryption Control Protocol" },
    { PPP_ECPFRAG,  "ECP-Link", interpret_ppp_cp, "PPP-ECP-Link:  ",
        "Per-Link Encryption Control Protocol" },
    { PPP_MPLSCP,   "MPLSCP",       NULL,   NULL,   NULL },
    { PPP_OSINLCP,  "OSINLCP",      NULL,   NULL,   NULL },
    { PPP_ATCP, "ATCP",         NULL,   NULL,   NULL },
    { PPP_IPXCP,    "IPXCP",        NULL,   NULL,   NULL },
    { PPP_BACP, "BACP",         NULL,   NULL,   NULL },
    { PPP_BCP,  "BCP",          NULL,   NULL,   NULL },
    { PPP_CBCP, "CBCP",         NULL,   NULL,   NULL },
    { PPP_BAP,  "BAP",          NULL,   NULL,   NULL },
    { PPP_CHAP, "CHAP",     interpret_ppp_chap, "CHAP:  ",
        "Challenge Handshake Authentication Protocl" },
    { PPP_PAP,  "PAP",      interpret_ppp_pap,  "PAP:   ",
        "Password Authentication Protocol" },
    { PPP_EAP,  "EAP",          NULL,   NULL,   NULL },
    { 0,        unknown_string,     NULL,   NULL,   NULL }
};

static cp_optinfo_t lcp_optinfo[] = {
    { OPT_LCP_VENDOR,   "Vendor-Specific",      6,
        opt_format_vendor },
    { OPT_LCP_MRU,      "Maximum-Receive-Unit",     4,
        opt_format_mru },
    { OPT_LCP_ASYNCMAP, "Async-Control-Character-Map",  6,
        opt_format_accm },
    { OPT_LCP_AUTHTYPE, "Authentication-Protocol",  4,
        opt_format_authproto },
    { OPT_LCP_QUALITY,  "Quality-Protocol",     4,
        opt_format_qualproto },
    { OPT_LCP_MAGICNUMBER,  "Magic-Number",         6,
        opt_format_magicnum },
    { OPT_LCP_PCOMPRESSION, "Protocol-Field-Compression",   2,  NULL },
    { OPT_LCP_ACCOMPRESSION, "Address-and-Control-Field-Compression", 2,
        NULL },
    { OPT_LCP_FCSALTERN,    "FCS-Alternative",      3,
        opt_format_fcs },
    { OPT_LCP_SELFDESCPAD,  "Self-Describing-Padding",  3,
        opt_format_sdp },
    { OPT_LCP_NUMBERED, "Numbered-Mode",        3,
        opt_format_nummode },
    { OPT_LCP_MULTILINKPROC, "Multi-Link-Procedure",    2,  NULL },
    { OPT_LCP_CALLBACK, "Callback",         3,
        opt_format_callback },
    { OPT_LCP_CONNECTTIME,  "Connect-Time",         2,  NULL },
    { OPT_LCP_COMPOUNDFRAMES, "Compound-Frames",        2,  NULL },
    { OPT_LCP_DATAENCAP,    "Nominal-Data-Encapsulation",   2,  NULL },
    { OPT_LCP_MRRU,     "Multilink-MRRU",       4,
        opt_format_mrru },
    { OPT_LCP_SSNHF,    "Multilink-Short-Sequence-Number-Header-Format",
        2, NULL },
    { OPT_LCP_EPDISC,   "Multilink-Endpoint-Discriminator", 3,
        opt_format_epdisc },
    { OPT_LCP_DCEIDENT, "DCE-Identifier",       3,
        opt_format_dce },
    { OPT_LCP_MLPLUSPROC,   "Multi-Link-Plus-Procedure",    2,  NULL },
    { OPT_LCP_LINKDISC, "Link Discriminator for BACP",  4,
        opt_format_linkdisc },
    { OPT_LCP_AUTH,     "LCP-Authentication-Option",    2,  NULL },
    { OPT_LCP_COBS,     "COBS",             2,  NULL },
    { OPT_LCP_PFXELISION,   "Prefix elision",       2,  NULL },
    { OPT_LCP_MPHDRFMT, "Multilink header format",  2,  NULL },
    { OPT_LCP_I18N,     "Internationalization",     6,
        opt_format_i18n },
    { OPT_LCP_SDL,      "Simple Data Link on SONET/SDH", 2, NULL },
    { OPT_LCP_MUXING,   "Old PPP Multiplexing",     2,  NULL },
    { 0,            unknown_string,         0,  NULL }
};

static cp_optinfo_t ipcp_optinfo[] = {
    { OPT_IPCP_ADDRS,   "IP-Addresses",         10,
        opt_format_ipaddresses },
    { OPT_IPCP_COMPRESSTYPE, "IP-Compression-Protocol", 4,
        opt_format_ipcompproto },
    { OPT_IPCP_ADDR,    "IP-Address",           6,
        opt_format_ipaddress },
    { OPT_IPCP_MOBILEIPV4,  "Mobile-IPv4",          6,
        opt_format_mobileipv4 },
    { OPT_IPCP_DNS1,    "Primary DNS Address",      6,
        opt_format_ipaddress },
    { OPT_IPCP_NBNS1,   "Primary NBNS Address",     6,
        opt_format_ipaddress },
    { OPT_IPCP_DNS2,    "Secondary DNS Address",    6,
        opt_format_ipaddress },
    { OPT_IPCP_NBNS2,   "Secondary NBNS Address",   6,
        opt_format_ipaddress },
    { OPT_IPCP_SUBNET,  "IP-Subnet",            6,
        opt_format_ipaddress },
    { 0,            unknown_string,         0,  NULL }
};

static cp_optinfo_t ipv6cp_optinfo[] = {
    { OPT_IPV6CP_IFACEID,   "Interface-Identifier",     10,
        opt_format_ifaceid },
    { OPT_IPV6CP_COMPRESSTYPE, "IPv6-Compression-Protocol", 4,
        opt_format_ipv6compproto },
    { 0,            unknown_string,         0,  NULL }
};

static cp_optinfo_t ccp_optinfo[] = {
    { OPT_CCP_PROPRIETARY,  "Proprietary Compression OUI",  6,
        opt_format_compoui },
    { OPT_CCP_PREDICTOR1,   "Predictor type 1",     2,  NULL },
    { OPT_CCP_PREDICTOR2,   "Predictor type 2",     2,  NULL },
    { OPT_CCP_PUDDLEJUMP,   "Puddle Jumper",        2,  NULL },
    { OPT_CCP_HPPPC,    "Hewlett-Packard PPC",      2,  NULL },
    { OPT_CCP_STACLZS,  "Stac Electronics LZS",     5,
        opt_format_staclzs },
    { OPT_CCP_MPPC,     "Microsoft PPC",        6,
        opt_format_mppc },
    { OPT_CCP_GANDALFFZA,   "Gandalf FZA",          3,
        opt_format_gandalf },
    { OPT_CCP_V42BIS,   "V.42bis compression",      2,
        NULL },
    { OPT_CCP_BSDCOMP,  "BSD LZW Compress",     3,
        opt_format_bsdcomp },
    { OPT_CCP_LZSDCP,   "LZS-DCP",          6,
        opt_format_lzsdcp },
    { OPT_CCP_MAGNALINK,    "Magnalink",            4,
        opt_format_magnalink },
    { OPT_CCP_DEFLATE,  "Deflate",          4,
        opt_format_deflate },
    { 0,            unknown_string,         0,  NULL }
};

static cp_optinfo_t ecp_optinfo[] = {
    { OPT_ECP_PROPRIETARY,  "Proprietary Encryption OUI",   6,
        opt_format_encroui },
    { OPT_ECP_DESE,     "DESE",             10,
        opt_format_dese },
    { OPT_ECP_3DESE,    "3DESE",            10,
        opt_format_dese },
    { OPT_ECP_DESEBIS,  "DESE-bis",         10,
        opt_format_dese },
    { 0,            unknown_string,         0,  NULL }
};

static cp_optinfo_t muxcp_optinfo[] = {
    { OPT_MUXCP_DEFAULTPID, "Default PID",          4,
        opt_format_muxpid },
    { 0,            unknown_string,         0,  NULL }
};

static char *cp_codearray[] = {
    "(Vendor Specific)",
    "(Configure-Request)",
    "(Configure-Ack)",
    "(Configure-Nak)",
    "(Configure-Reject)",
    "(Terminate-Request)",
    "(Terminate-Ack)",
    "(Code-Reject)",
    "(Protocol-Reject)",
    "(Echo-Request)",
    "(Echo-Reply)",
    "(Discard-Request)",
    "(Identification)",
    "(Time-Remaining)",
    "(Reset-Request)",
    "(Reset-Ack)"
};
#define MAX_CPCODE  ((sizeof (cp_codearray) / sizeof (char *)) - 1)

static char *pap_codearray[] = {
    "(Unknown)",
    "(Authenticate-Request)",
    "(Authenticate-Ack)",
    "(Authenticate-Nak)"
};
#define MAX_PAPCODE ((sizeof (pap_codearray) / sizeof (char *)) - 1)

static char *chap_codearray[] = {
    "(Unknown)",
    "(Challenge)",
    "(Response)",
    "(Success)",
    "(Failure)"
};
#define MAX_CHAPCODE    ((sizeof (chap_codearray) / sizeof (char *)) - 1)


int
interpret_ppp(int flags, uchar_t *data, int len)
{
    uint16_t protocol;
    ppp_protoinfo_t *protoinfo;
    uchar_t *payload = data;

    if (len < 2)
        return (len);

    GETINT16(protocol, payload);
    len -= sizeof (uint16_t);

    protoinfo = ppp_getprotoinfo(protocol);

    if (flags & F_SUM) {
        (void) sprintf(get_sum_line(),
            "PPP Protocol=0x%x (%s)", protocol, protoinfo->name);
    } else { /* F_DTAIL */
        show_header("PPP:    ", "Point-to-Point Protocol", len);
        show_space();
        (void) sprintf(get_line(0, 0), "Protocol = 0x%x (%s)",
            protocol, protoinfo->name);
        show_space();
    }

    if (protoinfo->interpret_proto != NULL) {
        len = protoinfo->interpret_proto(flags, payload, len,
            protoinfo);
    }

    return (len);
}

/*
 * interpret_ppp_cp() - Interpret PPP control protocols.  It is convenient
 * to do some of the decoding of these protocols in a common function since
 * they share packet formats.  This function expects to receive data
 * starting with the code field.
 */
static int
interpret_ppp_cp(int flags, uchar_t *data, int len, ppp_protoinfo_t *protoinfo)
{
    uint8_t code;
    uint8_t id;
    char *codestr;
    uint16_t length;
    uchar_t *datap = data;

    if (len < sizeof (ppp_pkt_t))
        return (len);

    GETINT8(code, datap);
    GETINT8(id, datap);
    GETINT16(length, datap);

    len -= sizeof (ppp_pkt_t);

    if (code <= MAX_CPCODE)
        codestr = cp_codearray[code];
    else
        codestr = "";

    if (flags & F_SUM) {
        (void) sprintf(get_sum_line(),
            "%s%s", protoinfo->prefix, codestr);
    } else { /* (flags & F_DTAIL) */
        show_header(protoinfo->prefix, protoinfo->description, len);
        show_space();

        (void) sprintf(get_line(0, 0), "Code = %d %s", code, codestr);
        (void) sprintf(get_line(0, 0), "Identifier = %d", id);
        (void) sprintf(get_line(0, 0), "Length = %d", length);

        show_space();

        len = MIN(len, length - sizeof (ppp_pkt_t));
        if (len == 0)
            return (len);

        switch (code) {
        case CODE_VENDOR: {
            uint32_t magicnum;
            uint32_t oui;
            char *ouistr;
            uint8_t kind;

            if (len < sizeof (magicnum) + sizeof (oui))
                return (len);

            GETINT32(magicnum, datap);
            (void) sprintf(get_line(0, 0), "Magic-Number = 0x%08x",
                magicnum);

            GETINT32(oui, datap);
            kind = oui & 0x000000ff;
            oui >>= 8;

            ouistr = ether_ouiname(oui);
            if (ouistr == NULL)
                ouistr = unknown_string;

            (void) sprintf(get_line(0, 0), "OUI = 0x%06x (%s)",
                oui, ouistr);
            (void) sprintf(get_line(0, 0), "Kind = %d", kind);
            show_space();
            break;
        }

        case CODE_CONFREQ:
        case CODE_CONFACK:
        case CODE_CONFNAK:
        case CODE_CONFREJ:
            /*
             * The above all contain protocol specific
             * configuration options.  Parse these options.
             */
            interpret_cp_options(datap, len, protoinfo);
            break;

        case CODE_TERMREQ:
        case CODE_TERMACK:
            /*
             * The arbitrary data in these two packet types
             * is almost always plain text.  Print it as such.
             */
            (void) sprintf(get_line(0, 0), "Data = %.*s",
                length - sizeof (ppp_pkt_t), datap);
            show_space();
            break;

        case CODE_CODEREJ:
            /*
             * What follows is the rejected control protocol
             * packet, starting with the code field.
             * Conveniently, we can call interpret_ppp_cp() to
             * decode this.
             */
            prot_nest_prefix = protoinfo->prefix;
            interpret_ppp_cp(flags, datap, len, protoinfo);
            prot_nest_prefix = "";
            break;

        case CODE_PROTREJ:
            /*
             * We don't print the rejected-protocol field
             * explicitely.  Instead, we cheat and pretend that
             * the rejected-protocol field is actually the
             * protocol field in the included PPP packet.  This
             * way, we can invoke interpret_ppp() and have it
             * treat the included packet normally.
             */
            prot_nest_prefix = protoinfo->prefix;
            interpret_ppp(flags, datap, len);
            prot_nest_prefix = "";
            break;

        case CODE_ECHOREQ:
        case CODE_ECHOREP:
        case CODE_DISCREQ:
        case CODE_IDENT:
        case CODE_TIMEREMAIN: {
            uint32_t magicnum;
            char *message_label = "Identification = %.*s";

            if (len < sizeof (uint32_t))
                break;

            GETINT32(magicnum, datap);
            len -= sizeof (uint32_t);
            (void) sprintf(get_line(0, 0), "Magic-Number = 0x%08x",
                magicnum);
            /*
             * Unless this is an identification or
             * time-remaining packet, arbitrary data follows
             * the magic number field.  The user can take a
             * look at the hex dump for enlightenment.
             */
            if (code == CODE_TIMEREMAIN) {
                uint32_t timeremaining;

                if (len < sizeof (uint32_t))
                    break;

                message_label = "Message = %.*s";

                GETINT32(timeremaining, datap);
                len -= sizeof (uint32_t);
                (void) sprintf(get_line(0, 0),
                    "Seconds Remaining = %d", timeremaining);
            }

            if (code == CODE_IDENT || code == CODE_TIMEREMAIN) {
                if (len == 0)
                    break;

                (void) sprintf(get_line(0, 0), message_label,
                    len, datap);
            }
            show_space();
            break;
        }

        /*
         * Reset-Request and Reset-Ack contain arbitrary data which
         * the user can sift through using the -x option.
         */
        case CODE_RESETREQ:
        case CODE_RESETACK:
        default:
            break;
        }
    }
    return (len);
}


/*
 * interpret_cp_options() decodes control protocol configuration options.
 * Since each control protocol has a different set of options whose type
 * numbers overlap, the protoinfo parameter is used to get a handle on
 * which option set to use for decoding.
 */
static int
interpret_cp_options(uchar_t *optptr, int len, ppp_protoinfo_t *protoinfo)
{
    cp_optinfo_t *optinfo;
    cp_optinfo_t *optinfo_ptr;
    uint8_t optlen;
    uint8_t opttype;

    switch (protoinfo->proto) {
    case PPP_LCP:
        optinfo = lcp_optinfo;
        break;
    case PPP_IPCP:
        optinfo = ipcp_optinfo;
        break;
    case PPP_IPV6CP:
        optinfo = ipv6cp_optinfo;
        break;
    case PPP_CCP:
        optinfo = ccp_optinfo;
        break;
    case PPP_ECP:
        optinfo = ecp_optinfo;
        break;
    case PPP_MUXCP:
        optinfo = muxcp_optinfo;
        break;
    default:
        return (len);
        break;
    }

    if (len >= 2) {
        (void) sprintf(get_line(0, 0), "%s Configuration Options",
            protoinfo->name);
        show_space();
    }

    while (len >= 2) {
        GETINT8(opttype, optptr);
        GETINT8(optlen, optptr);

        optinfo_ptr = ppp_getoptinfo(optinfo, opttype);

        (void) sprintf(get_line(0, 0), "Option Type = %d (%s)", opttype,
            optinfo_ptr->opt_name);
        (void) sprintf(get_line(0, 0), "Option Length = %d", optlen);

        /*
         * Don't continue if there isn't enough data to
         * contain this option, or if this type of option
         * should contain more data than the length field
         * claims there is.
         */
        if (optlen > len || optlen < optinfo_ptr->opt_minsize) {
            (void) sprintf(get_line(0, 0),
                "Warning: Incomplete Option");
            show_space();
            break;
        }

        if (optinfo_ptr->opt_formatdata != NULL) {
            optinfo_ptr->opt_formatdata(optptr,
                MIN(optlen - 2, len - 2));
        }

        len -= optlen;
        optptr += optlen - 2;

        show_space();
    }

    return (len);
}

static int
interpret_ppp_chap(int flags, uchar_t *data, int len,
    ppp_protoinfo_t *protoinfo)
{
    uint8_t code;
    uint8_t id;
    char *codestr;
    uint16_t length;
    int lengthleft;
    uchar_t *datap = data;


    if (len < sizeof (ppp_pkt_t))
        return (len);

    GETINT8(code, datap);
    GETINT8(id, datap);
    GETINT8(length, datap);

    if (code <= MAX_CHAPCODE)
        codestr = chap_codearray[code];
    else
        codestr = "";

    if (flags & F_SUM) {
        (void) sprintf(get_sum_line(),
            "%s%s", protoinfo->prefix, codestr);
    } else { /* (flags & F_DTAIL) */
        show_header(protoinfo->prefix, protoinfo->description, len);
        show_space();

        (void) sprintf(get_line(0, 0), "Code = %d %s", code, codestr);
        (void) sprintf(get_line(0, 0), "Identifier = %d", id);
        (void) sprintf(get_line(0, 0), "Length = %d", length);

        show_space();

        if (len < length)
            return (len);

        lengthleft = len - sizeof (ppp_pkt_t);

        switch (code) {
        case CODE_CHALLENGE:
        case CODE_RESPONSE: {
            uint8_t value_size;
            uint16_t peername_size;

            if (lengthleft < sizeof (value_size))
                break;

            GETINT8(value_size, datap);
            lengthleft -= sizeof (value_size);
            (void) sprintf(get_line(0, 0), "Value-Size = %d",
                value_size);

            if (lengthleft < sizeof (peername_size))
                break;
            peername_size = MIN(length - sizeof (ppp_pkt_t) -
                value_size, lengthleft);
            (void) sprintf(get_line(0, 0), "Name = %.*s",
                peername_size, datap + value_size);

            break;
        }
        case CODE_SUCCESS:
        case CODE_FAILURE: {
            uint16_t message_size = MIN(length - sizeof (ppp_pkt_t),
                lengthleft);

            (void) sprintf(get_line(0, 0), "Message = %.*s",
                message_size, datap);
            break;
        }
        default:
            break;
        }
    }

    show_space();
    len -= length;
    return (len);
}

static int
interpret_ppp_pap(int flags, uchar_t *data, int len,
    ppp_protoinfo_t *protoinfo)
{
    uint8_t code;
    uint8_t id;
    char *codestr;
    uint16_t length;
    int lengthleft;
    uchar_t *datap = data;

    if (len < sizeof (ppp_pkt_t))
        return (len);

    GETINT8(code, datap);
    GETINT8(id, datap);
    GETINT16(length, datap);

    lengthleft = len - sizeof (ppp_pkt_t);

    if (code <= MAX_PAPCODE)
        codestr = pap_codearray[code];
    else
        codestr = "";

    if (flags & F_SUM) {
        (void) sprintf(get_sum_line(),
            "%s%s", protoinfo->prefix, codestr);
    } else { /* (flags & F_DTAIL) */
        show_header(protoinfo->prefix, protoinfo->description, len);
        show_space();

        (void) sprintf(get_line(0, 0), "Code = %d %s", code, codestr);
        (void) sprintf(get_line(0, 0), "Identifier = %d", id);
        (void) sprintf(get_line(0, 0), "Length = %d", length);

        show_space();

        if (len < length)
            return (len);

        switch (code) {
        case CODE_AUTHREQ: {
            uint8_t fieldlen;

            if (lengthleft < sizeof (fieldlen))
                break;
            GETINT8(fieldlen, datap);
            (void) sprintf(get_line(0, 0), "Peer-Id Length = %d",
                fieldlen);
            lengthleft -= sizeof (fieldlen);

            if (lengthleft < fieldlen)
                break;
            (void) sprintf(get_line(0, 0), "Peer-Id = %.*s",
                fieldlen, datap);
            lengthleft -= fieldlen;

            datap += fieldlen;

            if (lengthleft < sizeof (fieldlen))
                break;
            GETINT8(fieldlen, datap);
            (void) sprintf(get_line(0, 0), "Password Length = %d",
                fieldlen);
            lengthleft -= sizeof (fieldlen);

            if (lengthleft < fieldlen)
                break;
            (void) sprintf(get_line(0, 0), "Password = %.*s",
                fieldlen, datap);

            break;
        }
        case CODE_AUTHACK:
        case CODE_AUTHNAK: {
            uint8_t msglen;

            if (lengthleft < sizeof (msglen))
                break;
            GETINT8(msglen, datap);
            (void) sprintf(get_line(0, 0), "Msg-Length = %d",
                msglen);
            lengthleft -= sizeof (msglen);

            if (lengthleft < msglen)
                break;
            (void) sprintf(get_line(0, 0), "Message = %.*s",
                msglen, datap);

            break;
        }
        default:
            break;
        }
    }

    show_space();
    len -= length;
    return (len);
}


static int
interpret_ppp_lqr(int flags, uchar_t *data, int len,
    ppp_protoinfo_t *protoinfo)
{
    lqr_pkt_t lqr_pkt;
    if (len < sizeof (lqr_pkt_t))
        return (len);

    (void) memcpy(&lqr_pkt, data, sizeof (lqr_pkt_t));

    if (flags & F_SUM) {
        (void) sprintf(get_sum_line(), protoinfo->prefix);
    } else { /* (flags & F_DTAIL) */
        show_header(protoinfo->prefix, protoinfo->description, len);
        show_space();

        (void) sprintf(get_line(0, 0), "Magic-Number =   0x%08x",
            ntohl(lqr_pkt.lqr_magic));
        (void) sprintf(get_line(0, 0), "LastOutLQRs =    %d",
            ntohl(lqr_pkt.lqr_lastoutlqrs));
        (void) sprintf(get_line(0, 0), "LastOutPackets = %d",
            ntohl(lqr_pkt.lqr_lastoutpackets));
        (void) sprintf(get_line(0, 0), "LastOutOctets =  %d",
            ntohl(lqr_pkt.lqr_lastoutoctets));
        (void) sprintf(get_line(0, 0), "PeerInLQRs =     %d",
            ntohl(lqr_pkt.lqr_peerinlqrs));
        (void) sprintf(get_line(0, 0), "PeerInPackets =  %d",
            ntohl(lqr_pkt.lqr_peerinpackets));
        (void) sprintf(get_line(0, 0), "PeerInDiscards = %d",
            ntohl(lqr_pkt.lqr_peerindiscards));
        (void) sprintf(get_line(0, 0), "PeerInErrors =   %d",
            ntohl(lqr_pkt.lqr_peerinerrors));
        (void) sprintf(get_line(0, 0), "PeerInOctets =   %d",
            ntohl(lqr_pkt.lqr_peerinoctets));
        (void) sprintf(get_line(0, 0), "PeerOutLQRs =    %d",
            ntohl(lqr_pkt.lqr_peeroutlqrs));
        (void) sprintf(get_line(0, 0), "PeerOutPackets = %d",
            ntohl(lqr_pkt.lqr_peeroutpackets));
        (void) sprintf(get_line(0, 0), "PeerOutOctets =  %d",
            ntohl(lqr_pkt.lqr_peeroutoctets));

        show_space();
    }

    len -= sizeof (lqr_pkt_t);
    return (len);
}

static ppp_protoinfo_t *
ppp_getprotoinfo(uint16_t proto)
{
    ppp_protoinfo_t *protoinfo_ptr = &protoinfo_array[0];

    while (protoinfo_ptr->proto != proto && protoinfo_ptr->proto != 0) {
        protoinfo_ptr++;
    }

    return (protoinfo_ptr);
}


static cp_optinfo_t *
ppp_getoptinfo(cp_optinfo_t optinfo_list[], uint16_t opt_type)
{
    cp_optinfo_t *optinfo_ptr = &optinfo_list[0];

    while (optinfo_ptr->opt_type != opt_type &&
        optinfo_ptr->opt_name != unknown_string) {
        optinfo_ptr++;
    }

    return (optinfo_ptr);
}


/*
 * Below are the functions which parse control protocol configuration
 * options.  The first argument to these functions (optdata) points to the
 * first byte of the option after the length field.  The second argument
 * (size) is the number of bytes in the option after the length field
 * (length - 2).
 */

/*
 * The format of the Vendor-Specific option (rfc2153) is:
 *
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |              OUI
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *        ...      |     Kind      |  Value(s) ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
 */
/*ARGSUSED1*/
static void
opt_format_vendor(uchar_t *optdata, uint8_t size)
{
    uint32_t oui;
    char *ouistr;
    uint8_t kind;

    GETINT32(oui, optdata);
    kind = oui & 0x000000ff;
    oui >>= 8;

    ouistr = ether_ouiname(oui);
    if (ouistr == NULL)
        ouistr = unknown_string;

    (void) sprintf(get_line(0, 0), "OUI = 0x%06x (%s)", oui, ouistr);
    (void) sprintf(get_line(0, 0), "Kind = %d", kind);
}

/*
 * The format of the MRU option (rfc1661) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |      Maximum-Receive-Unit     |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_mru(uchar_t *optdata, uint8_t size)
{
    uint16_t mru;

    GETINT16(mru, optdata);
    (void) sprintf(get_line(0, 0), "MRU = %d", mru);
}

/*
 * The format of the accm option (rfc1662) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |               ACCM
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *           ACCM (cont)           |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_accm(uchar_t *optdata, uint8_t size)
{
    uint32_t accm;

    GETINT32(accm, optdata);
    (void) sprintf(get_line(0, 0), "ACCM = 0x%08x", accm);
}

/*
 * The format of the Authentication-Protocol option (rfc1661) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |     Authentication-Protocol   |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |    Data ...
 * +-+-+-+-+
 *
 * For PAP (rfc1334), there is no data.  For CHAP (rfc1994), there is one
 * byte of data representing the algorithm.
 */
static void
opt_format_authproto(uchar_t *optdata, uint8_t size)
{
    uint16_t proto;
    ppp_protoinfo_t *auth_protoinfo;

    GETINT16(proto, optdata);

    auth_protoinfo = ppp_getprotoinfo(proto);

    (void) sprintf(get_line(0, 0), "Protocol = 0x%x (%s)", proto,
        auth_protoinfo->name);

    switch (proto) {
    case PPP_CHAP: {
        uint8_t algo;
        char *algostr;

        if (size < sizeof (proto) + sizeof (algo))
            return;

        GETINT8(algo, optdata);
        switch (algo) {
        case 5:
            algostr = "CHAP with MD5";
            break;
        case 128:
            algostr = "MS-CHAP";
            break;
        case 129:
            algostr = "MS-CHAP-2";
            break;
        default:
            algostr = unknown_string;
            break;
        }
        (void) sprintf(get_line(0, 0), "Algorithm = %d (%s)", algo,
            algostr);
        break;
    }
    default:
        break;
    }
}

/*
 * The format of the Quality Protocol option (rfc1661) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |        Quality-Protocol       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |    Data ...
 * +-+-+-+-+
 *
 * For LQR, the data consists of a 4 byte reporting period.
 */
static void
opt_format_qualproto(uchar_t *optdata, uint8_t size)
{
    uint16_t proto;
    ppp_protoinfo_t *qual_protoinfo;

    GETINT16(proto, optdata);

    qual_protoinfo = ppp_getprotoinfo(proto);

    (void) sprintf(get_line(0, 0), "Protocol = 0x%x (%s)", proto,
        qual_protoinfo->name);

    switch (proto) {
    case PPP_LQR: {
        uint32_t reporting_period;

        if (size < sizeof (proto) + sizeof (reporting_period))
            return;

        GETINT32(reporting_period, optdata);
        (void) sprintf(get_line(0, 0), "Reporting-Period = %d",
            reporting_period);
        break;
    }
    default:
        break;
    }
}

/*
 * The format of the Magic Number option (rfc1661) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |          Magic-Number
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *       Magic-Number (cont)       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_magicnum(uchar_t *optdata, uint8_t size)
{
    uint32_t magicnum;

    GETINT32(magicnum, optdata);
    (void) sprintf(get_line(0, 0), "Magic Number = 0x%08x", magicnum);
}

/*
 * The format of the FCS-Alternatives option (rfc1570) is:
 *
 *  0                   1                   2
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |    Options    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_fcs(uchar_t *optdata, uint8_t size)
{
    uint8_t options;

    GETINT8(options, optdata);

    (void) sprintf(get_line(0, 0), "Options = 0x%02x", options);
    (void) sprintf(get_line(0, 0), "     %s",
        getflag(options, 0x01, "NULL FCS", ""));
    (void) sprintf(get_line(0, 0), "     %s",
        getflag(options, 0x02, "CCITT 16-bit FCS", ""));
    (void) sprintf(get_line(0, 0), "     %s",
        getflag(options, 0x04, "CCITT 32-bit FCS", ""));
}

/*
 * The format of the Self-Describing-Padding option (rfc1570) is:
 *
 *  0                   1                   2
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |    Maximum    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_sdp(uchar_t *optdata, uint8_t size)
{
    uint8_t max;

    GETINT8(max, optdata);

    (void) sprintf(get_line(0, 0), "Maximum = %d", max);
}

/*
 * The format of the Numbered-Mode option (rfc1663) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |     Length    |    Window     |   Address...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_nummode(uchar_t *optdata, uint8_t size)
{
    uint8_t window;

    GETINT8(window, optdata);
    (void) sprintf(get_line(0, 0), "Window = %d", window);
}

/*
 * The format of the Callback option (rfc1570) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |   Operation   |  Message ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
static void
opt_format_callback(uchar_t *optdata, uint8_t size)
{
    uint8_t operation;
    char *opstr;

    GETINT8(operation, optdata);
    switch (operation) {
    case 0:
        opstr = "User Authentication";
        break;
    case 1:
        opstr = "Dialing String";
        break;
    case 2:
        opstr = "Location Identifier";
        break;
    case 3:
        opstr = "E.164 Number";
        break;
    case 4:
        opstr = "X.500 Distinguished Name";
        break;
    case 6:
        opstr = "CBCP Negotiation";
        break;
    default:
        opstr = unknown_string;
        break;
    }

    (void) sprintf(get_line(0, 0), "Operation = %d (%s)", operation, opstr);

    if (size > sizeof (operation)) {
        (void) sprintf(get_line(0, 0), "Message = %.*s",
            size - sizeof (operation), optdata);
    }
}

/*
 * The format of the Multilink-MRRU option (rfc1990) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Type = 17   |   Length = 4  | Max-Receive-Reconstructed-Unit|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_mrru(uchar_t *optdata, uint8_t size)
{
    uint16_t mrru;

    GETINT16(mrru, optdata);
    (void) sprintf(get_line(0, 0), "MRRU = %d", mrru);
}

/*
 * The format of the Endpoint Discriminator option (rfc1990) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Type = 19   |     Length    |    Class      |  Address ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
static void
opt_format_epdisc(uchar_t *optdata, uint8_t size)
{
    uint8_t class;
    char *classstr;
    uint8_t addrlen = size - sizeof (class);
    char *addr;

    GETINT8(class, optdata);

    switch (class) {
    case 0:
        classstr = "Null Class";
        break;
    case 1:
        classstr = "Locally Assigned Address";
        break;
    case 2:
        classstr = "IPv4 Address";
        break;
    case 3:
        classstr = "IEE 802.1 Global MAC Address";
        break;
    case 4:
        classstr = "PPP Magic-Number Block";
        break;
    case 5:
        classstr = "Public Switched Network Directory Number";
        break;
    default:
        classstr = unknown_string;
        break;
    }

    (void) sprintf(get_line(0, 0), "Address Class = %d (%s)", class,
        classstr);

    if (addrlen == 0)
        return;

    addr = (char *)malloc(addrlen);
    (void) memcpy(addr, optdata, addrlen);
    switch (class) {
    case 2: {
        char addrstr[INET_ADDRSTRLEN];

        if (addrlen != sizeof (in_addr_t))
            break;
        if (inet_ntop(AF_INET, addr, addrstr, INET_ADDRSTRLEN) !=
            NULL) {
            (void) sprintf(get_line(0, 0), "Address = %s", addrstr);
        }
        break;
    }
    case 3: {
        char *addrstr;

        if (addrlen != sizeof (struct ether_addr))
            break;
        if ((addrstr = ether_ntoa((struct ether_addr *)addr)) != NULL) {
            (void) sprintf(get_line(0, 0), "Address = %s", addrstr);
        }
        break;
    }
    case 5: {
        /*
         * For this case, the address is supposed to be a plain
         * text telephone number.
         */
        (void) sprintf(get_line(0, 0), "Address = %.*s", addrlen,
            addr);
    }
    default:
        break;
    }

    free(addr);
}

/*
 * The DCE identifier option has the following format (from rfc1976):
 *
 *     0                   1                   2
 *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *    |     Type      |    Length     |      Mode     |
 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_dce(uchar_t *optdata, uint8_t size)
{
    uint8_t mode;
    char *modestr;

    GETINT8(mode, optdata);
    switch (mode) {
    case 1:
        modestr = "No Additional Negotiation";
        break;
    case 2:
        modestr = "Full PPP Negotiation and State Machine";
        break;
    default:
        modestr = unknown_string;
        break;
    }
    (void) sprintf(get_line(0, 0), "Mode = %d (%s)", mode, modestr);
}

/*
 * The format of the Link Discriminator option (rfc2125) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |     Length    |       Link Discriminator      |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_linkdisc(uchar_t *optdata, uint8_t size)
{
    uint16_t discrim;

    GETINT16(discrim, optdata);

    (void) sprintf(get_line(0, 0), "Link Discriminator = %d", discrim);
}


/*
 * The format of the Internationalization option (rfc2484) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |          MIBenum
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *           MIBenum (cont)        |        Language-Tag...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
static void
opt_format_i18n(uchar_t *optdata, uint8_t size)
{
    uint32_t mibenum;
    uint8_t taglen;

    taglen = size - sizeof (mibenum);

    GETINT32(mibenum, optdata);
    (void) sprintf(get_line(0, 0), "MIBenum = %d", mibenum);

    if (taglen > 0) {
        (void) sprintf(get_line(0, 0), "Language Tag = %.*s", taglen,
            optdata);
    }
}

/*
 * The format of the obsolete IP-Addresses option (rfc1172) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |     Source-IP-Address
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *   Source-IP-Address (cont)      |  Destination-IP-Address
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  Destination-IP-Address (cont)  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_ipaddresses(uchar_t *optdata, uint8_t size)
{
    in_addr_t addr;
    char addrstr[INET_ADDRSTRLEN];

    (void) memcpy(&addr, optdata, sizeof (in_addr_t));
    if (inet_ntop(AF_INET, &addr, addrstr, INET_ADDRSTRLEN) != NULL) {
        (void) sprintf(get_line(0, 0), "Source Address =      %s",
            addrstr);
    }

    optdata += sizeof (in_addr_t);

    (void) memcpy(&addr, optdata, sizeof (in_addr_t));
    if (inet_ntop(AF_INET, &addr, addrstr, INET_ADDRSTRLEN) != NULL) {
        (void) sprintf(get_line(0, 0), "Destination Address = %s",
            addrstr);
    }
}

/*
 * The format of the IP-Compression-Protocol option (rfc1332) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |     IP-Compression-Protocol   |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |    Data ...
 * +-+-+-+-+
 *
 * For VJ Compressed TCP/IP, data consists of:
 *
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Max-Slot-Id  | Comp-Slot-Id  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 * For IPHC (rfc2509), data consists of:
 *
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |           TCP_SPACE           |         NON_TCP_SPACE         |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |         F_MAX_PERIOD          |          F_MAX_TIME           |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |           MAX_HEADER          |          suboptions...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
static void
opt_format_ipcompproto(uchar_t *optdata, uint8_t size)
{
    uint16_t proto;
    ppp_protoinfo_t *comp_protoinfo;

    GETINT16(proto, optdata);

    comp_protoinfo = ppp_getprotoinfo(proto);

    (void) sprintf(get_line(0, 0), "Protocol = 0x%x (%s)", proto,
        comp_protoinfo->name);

    switch (proto) {
    case PPP_VJC_COMP: {
        uint8_t maxslotid;
        uint8_t compslotid;

        if (size < sizeof (proto) + sizeof (maxslotid) +
            sizeof (compslotid))
            break;

        GETINT8(maxslotid, optdata);
        GETINT8(compslotid, optdata);
        (void) sprintf(get_line(0, 0), "Max-Slot-Id = %d", maxslotid);
        (void) sprintf(get_line(0, 0), "Comp-Slot Flag = 0x%x",
            compslotid);
        break;
    }
    case PPP_FULLHDR: {
        uint16_t tcp_space;
        uint16_t non_tcp_space;
        uint16_t f_max_period;
        uint16_t f_max_time;
        uint16_t max_header;

        if (size < sizeof (proto) + sizeof (tcp_space) +
            sizeof (non_tcp_space) + sizeof (f_max_period) +
            sizeof (f_max_time) + sizeof (max_header))
            break;

        GETINT16(tcp_space, optdata);
        GETINT16(non_tcp_space, optdata);
        GETINT16(f_max_period, optdata);
        GETINT16(f_max_time, optdata);
        GETINT16(max_header, optdata);

        (void) sprintf(get_line(0, 0), "TCP_SPACE = %d", tcp_space);
        (void) sprintf(get_line(0, 0), "NON_TCP_SPACE = %d",
            non_tcp_space);
        (void) sprintf(get_line(0, 0), "F_MAX_PERIOD = %d",
            f_max_period);
        (void) sprintf(get_line(0, 0), "F_MAX_TIME = %d", f_max_time);
        (void) sprintf(get_line(0, 0), "MAX_HEADER = %d octets",
            max_header);
    }
    default:
        break;
    }
}

/*
 * The format of the IP-Address option (rfc1332) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |           IP-Address
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *         IP-Address (cont)       |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_ipaddress(uchar_t *optdata, uint8_t size)
{
    in_addr_t ipaddr;
    char addrstr[INET_ADDRSTRLEN];

    (void) memcpy(&ipaddr, optdata, sizeof (in_addr_t));
    if (inet_ntop(AF_INET, &ipaddr, addrstr, INET_ADDRSTRLEN) != NULL) {
        (void) sprintf(get_line(0, 0), "Address = %s", addrstr);
    }
}

/*
 * The format of the Mobile-IPv4 option (rfc2290) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |         Mobile Node's ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *       ...  Home Address         |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_mobileipv4(uchar_t *optdata, uint8_t size)
{
    in_addr_t ipaddr;
    char addrstr[INET_ADDRSTRLEN];

    (void) memcpy(&ipaddr, optdata, sizeof (in_addr_t));
    if (inet_ntop(AF_INET, &ipaddr, addrstr, INET_ADDRSTRLEN) != NULL) {
        (void) sprintf(get_line(0, 0),
            "Mobile Node's Home Address = %s", addrstr);
    }
}

/*
 * The format of the Interface-Identifier option (rfc2472) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     | Interface-Identifier (MS Bytes)
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *                      Interface-Identifier (cont)
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * Interface-Identifier (LS Bytes) |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_ifaceid(uchar_t *optdata, uint8_t size)
{
    in6_addr_t id;
    char idstr[INET6_ADDRSTRLEN];

    (void) memset(&id, 0, sizeof (in6_addr_t));
    (void) memcpy(&id.s6_addr[8], optdata, 8);

    if (inet_ntop(AF_INET6, &id, idstr, INET6_ADDRSTRLEN) != NULL) {
        (void) sprintf(get_line(0, 0), "Interface ID = %s", idstr);
    }
}

/*
 * The format of the IPv6-Compression-Protocol option (rfc2472) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |   IPv6-Compression-Protocol   |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |    Data ...
 * +-+-+-+-+
 */
static void
opt_format_ipv6compproto(uchar_t *optdata, uint8_t size)
{
    uint16_t proto;
    ppp_protoinfo_t *comp_protoinfo;

    GETINT16(proto, optdata);

    comp_protoinfo = ppp_getprotoinfo(proto);

    (void) sprintf(get_line(0, 0), "Protocol = 0x%x (%s)", proto,
        comp_protoinfo->name);

    switch (proto) {
    case PPP_FULLHDR: {
        uint16_t tcp_space;
        uint16_t non_tcp_space;
        uint16_t f_max_period;
        uint16_t f_max_time;
        uint16_t max_header;

        if (size < sizeof (proto) + sizeof (tcp_space) +
            sizeof (non_tcp_space) + sizeof (f_max_period) +
            sizeof (f_max_time) + sizeof (max_header))
            return;

        GETINT16(tcp_space, optdata);
        GETINT16(non_tcp_space, optdata);
        GETINT16(f_max_period, optdata);
        GETINT16(f_max_time, optdata);
        GETINT16(max_header, optdata);

        (void) sprintf(get_line(0, 0), "TCP_SPACE = %d", tcp_space);
        (void) sprintf(get_line(0, 0), "NON_TCP_SPACE = %d",
            non_tcp_space);
        (void) sprintf(get_line(0, 0), "F_MAX_PERIOD = %d",
            f_max_period);
        (void) sprintf(get_line(0, 0), "F_MAX_TIME = %d", f_max_time);
        (void) sprintf(get_line(0, 0), "MAX_HEADER = %d octets",
            max_header);
    }
    default:
        break;
    }
}

/*
 * The format of the Proprietary Compression OUI option (rfc1962) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |       OUI ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *       OUI       |    Subtype    |  Values...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
 */
/*ARGSUSED1*/
static void
opt_format_compoui(uchar_t *optdata, uint8_t size)
{
    uint32_t oui;
    uint8_t subtype;
    char *ouistr;

    GETINT32(oui, optdata);
    subtype = oui & 0x000000ff;
    oui >>= 8;

    ouistr = ether_ouiname(oui);
    if (ouistr == NULL)
        ouistr = unknown_string;
    (void) sprintf(get_line(0, 0), "OUI = 0x%06x (%s)", oui, ouistr);
    (void) sprintf(get_line(0, 0), "Subtype = 0x%x", subtype);
}

/*
 * The format of the Stac LZS configuration option (rfc1974) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |        History Count          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Check Mode  |
 * +-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_staclzs(uchar_t *optdata, uint8_t size)
{
    uint16_t hcount;
    uint8_t cmode;

    GETINT16(hcount, optdata);
    GETINT8(cmode, optdata);

    cmode &= 0x07;

    (void) sprintf(get_line(0, 0), "History Count = %d", hcount);
    (void) sprintf(get_line(0, 0), "Check Mode = %d", cmode);
}

/*
 * The format of MPPC configuration option (rfc2118) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |        Supported Bits         |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |       Supported Bits          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_mppc(uchar_t *optdata, uint8_t size)
{
    uint32_t sb;

    GETINT32(sb, optdata);

    (void) sprintf(get_line(0, 0), "Supported Bits = 0x%x", sb);
}

/*
 * The format of the Gandalf FZA configuration option (rfc1993) is:
 *
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |   History   |    Version ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_gandalf(uchar_t *optdata, uint8_t size)
{
    uint8_t history;

    GETINT8(history, optdata);
    (void) sprintf(get_line(0, 0), "Maximum History Size = %d bits",
        history);
}

/*
 * The format of the BSD Compress configuration option (rfc1977) is:
 *
 *  0                   1                   2
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     | Vers|   Dict  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_bsdcomp(uchar_t *optdata, uint8_t size)
{
    uint8_t version;
    uint8_t codesize;

    GETINT8(codesize, optdata);

    version = codesize >> 5;
    codesize &= 0x1f;

    (void) sprintf(get_line(0, 0), "Version = 0x%x", version);
    (void) sprintf(get_line(0, 0), "Maximum Code Size = %d bits", codesize);
}

/*
 * The format of the LZS-DCP configuration option (rfc1967) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |        History Count          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Check Mode  | Process Mode  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_lzsdcp(uchar_t *optdata, uint8_t size)
{
    uint16_t history;
    uint8_t mode;
    char *modestr;

    GETINT16(history, optdata);
    (void) sprintf(get_line(0, 0), "History Count = %d", history);

    /* check mode */
    GETINT8(mode, optdata);
    switch (mode) {
    case 0:
        modestr = "None";
        break;
    case 1:
        modestr = "LCB";
        break;
    case 2:
        modestr = "Sequence Number";
        break;
    case 3:
        modestr = "Sequence Number + LCB (default)";
        break;
    default:
        modestr = unknown_string;
        break;
    }
    (void) sprintf(get_line(0, 0), "Check Mode = %d (%s)", mode, modestr);

    /* process mode */
    GETINT8(mode, optdata);
    switch (mode) {
    case 0:
        modestr = "None (default)";
        break;
    case 1:
        modestr = "Process-Uncompressed";
        break;
    default:
        modestr = unknown_string;
        break;
    }
    (void) sprintf(get_line(0, 0), "Process Mode = %d (%s)", mode, modestr);

}

/*
 * The format of the Magnalink configuration option (rfc1975) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |FE |P| History |  # Contexts   |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_magnalink(uchar_t *optdata, uint8_t size)
{
    uint8_t features;
    uint8_t pflag;
    uint8_t history;
    uint8_t contexts;

    GETINT8(history, optdata);
    GETINT8(contexts, optdata);

    features = history >> 6;
    pflag = (history >> 5) & 0x01;
    history &= 0x1f;

    (void) sprintf(get_line(0, 0), "Features = 0x%d", features);
    (void) sprintf(get_line(0, 0), "Packet Flag = %d", pflag);
    (void) sprintf(get_line(0, 0), "History Size = %d", history);
    (void) sprintf(get_line(0, 0), "Contexts = %d", contexts);
}

/*
 * The format of the Deflate configuration option (rfc1979) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |Window | Method|    MBZ    |Chk|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_deflate(uchar_t *optdata, uint8_t size)
{
    uint8_t window;
    uint8_t method;
    uint8_t chk;

    GETINT8(method, optdata);
    window = method >> 4;
    method &= 0x0f;

    GETINT8(chk, optdata);
    chk &= 0x03;

    (void) sprintf(get_line(0, 0), "Maximum Window Size = %d", window);
    (void) sprintf(get_line(0, 0), "Compression Method = 0x%x", method);
    (void) sprintf(get_line(0, 0), "Check Method = 0x%x", chk);
}

/*
 * The format of the Proprietary Encryption OUI option (rfc1968) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |     Type      |    Length     |       OUI ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *       OUI       |    Subtype    |  Values...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
 */
/*ARGSUSED1*/
static void
opt_format_encroui(uchar_t *optdata, uint8_t size)
{
    uint32_t oui;
    uint8_t subtype;
    char *ouistr;

    GETINT32(oui, optdata);
    subtype = oui & 0x000000ff;
    oui >>= 8;

    ouistr = ether_ouiname(oui);
    if (ouistr == NULL)
        ouistr = unknown_string;
    (void) sprintf(get_line(0, 0), "OUI = 0x%06x (%s)", oui, ouistr);
    (void) sprintf(get_line(0, 0), "Subtype = 0x%x", subtype);
}

/*
 * The format of the DESE, DESE-bis, and 3DESE configuration options
 * (rfc1969, rfc2419, and rfc2420) are:
 *
 * 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 = 3    |    Length     |         Initial Nonce ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_dese(uchar_t *optdata, uint8_t size)
{
    (void) sprintf(get_line(0, 0),
        "Initial Nonce = 0x%02x%02x%02x%02x%02x%02x%02x%02x",
        optdata[0], optdata[1], optdata[2], optdata[3], optdata[4],
        optdata[5], optdata[6], optdata[7]);
}

/*
 * The format of the PPPMux Default Protocol Id option
 * (draft-ietf-pppext-pppmux-02.txt) 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
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |   Type = 1    |   Length = 4  |        Default PID            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
/*ARGSUSED1*/
static void
opt_format_muxpid(uchar_t *optdata, uint8_t size)
{
    uint16_t defpid;

    GETINT16(defpid, optdata);
    (void) sprintf(get_line(0, 0), "Default PID = %d", defpid);
}