tcpdump/print-isoclns.c

/*
 * Copyright (c) 1992, 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.
 *
 * Original code by Matt Thomas, Digital Equipment Corporation
 *
 * Extensively modified by Hannes Gredler (hannes@juniper.net) for more
 * complete IS-IS support.
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/tcpdump/print-isoclns.c,v 1.56 2002-08-01 08:53:13 risso Exp $ (LBL)";
#endif

#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 "ethertype.h"
#include "ether.h"
#include "extract.h"

#define	NLPID_CLNS	129	/* 0x81 */
#define	NLPID_ESIS	130	/* 0x82 */
#define	NLPID_ISIS	131	/* 0x83 */
#define NLPID_IP6       0x8e
#define NLPID_IP        0xcc
#define	NLPID_NULLNS	0

/*
 * IS-IS is defined in ISO 10589.  Look there for protocol definitions.
 */

#define SYSTEM_ID_LEN	ETHER_ADDR_LEN
#define NODE_ID_LEN     SYSTEM_ID_LEN+1
#define LSP_ID_LEN      SYSTEM_ID_LEN+2

#define ISIS_VERSION	1
#define PDU_TYPE_MASK	0x1F
#define PRIORITY_MASK	0x7F

#define L1_LAN_IIH	15
#define L2_LAN_IIH	16
#define PTP_IIH		17
#define L1_LSP       	18
#define L2_LSP       	20
#define L1_CSNP  	24
#define L2_CSNP  	25
#define L1_PSNP		26
#define L2_PSNP		27

static struct tok isis_pdu_values[] = {
    { L1_LAN_IIH,       "L1 Lan IIH"},
    { L2_LAN_IIH,       "L2 Lan IIH"},
    { PTP_IIH,          "p2p IIH"},
    { L1_LSP,           "L1 LSP"},
    { L2_LSP,           "L2 LSP"},
    { L1_CSNP,          "L1 CSNP"},
    { L2_CSNP,          "L2 CSNP"},
    { L1_PSNP,          "L1 PSNP"},
    { L2_PSNP,          "L2 PSNP"},
    { 0, NULL}
};

/*
 * A TLV is a tuple of a type, length and a value and is normally used for
 * encoding information in all sorts of places.  This is an enumeration of
 * the well known types.
 *
 * list taken from draft-ietf-isis-wg-tlv-codepoints-01.txt
 */

#define TLV_AREA_ADDR           1
#define TLV_IS_REACH            2
#define TLV_ESNEIGH             3
#define TLV_PART_DIS            4
#define TLV_PREFIX_NEIGH        5
#define TLV_ISNEIGH             6
#define TLV_ISNEIGH_VARLEN      7
#define TLV_PADDING             8
#define TLV_LSP                 9
#define TLV_AUTH                10
#define TLV_CHECKSUM            12
#define TLV_LSP_BUFFERSIZE      14
#define TLV_EXT_IS_REACH        22
#define TLV_IS_ALIAS_ID         24
#define TLV_DECNET_PHASE4       42
#define TLV_LUCENT_PRIVATE      66
#define TLV_IP_REACH            128
#define TLV_PROTOCOLS           129
#define TLV_IP_REACH_EXT        130
#define TLV_IDRP_INFO           131
#define TLV_IPADDR              132
#define TLV_IPAUTH              133
#define TLV_TE_ROUTER_ID        134
#define TLV_EXT_IP_REACH        135
#define TLV_HOSTNAME            137
#define TLV_SHARED_RISK_GROUP   138
#define TLV_NORTEL_PRIVATE1     176
#define TLV_NORTEL_PRIVATE2     177
#define TLV_RESTART_SIGNALING   211
#define TLV_MT_IS_REACH         222
#define TLV_MT_SUPPORTED        229
#define TLV_IP6ADDR             232
#define TLV_MT_IP_REACH         235
#define TLV_IP6_REACH           236
#define TLV_MT_IP6_REACH        237
#define TLV_PTP_ADJ             240

static struct tok isis_tlv_values[] = {
    { TLV_AREA_ADDR,	     "Area address(es)"},
    { TLV_IS_REACH,          "IS Reachability"},
    { TLV_ESNEIGH,           "ES Neighbor(s)"},
    { TLV_PART_DIS,          "Partition DIS"},
    { TLV_PREFIX_NEIGH,      "Prefix Neighbors"},
    { TLV_ISNEIGH,           "IS Neighbor(s)"},
    { TLV_ISNEIGH_VARLEN,    "IS Neighbor(s) (variable length)"},
    { TLV_PADDING,           "Padding"},
    { TLV_LSP,               "LSP entries"},
    { TLV_AUTH,              "Authentication"},
    { TLV_CHECKSUM,          "Checksum"},
    { TLV_LSP_BUFFERSIZE,    "LSP Buffersize"},
    { TLV_EXT_IS_REACH,      "Extended IS Reachability"},
    { TLV_IS_ALIAS_ID,       "IS Alias ID"},
    { TLV_DECNET_PHASE4,     "DECnet Phase IV"},
    { TLV_LUCENT_PRIVATE,    "Lucent Proprietary"},
    { TLV_IP_REACH,          "IPv4 Internal reachability"},
    { TLV_PROTOCOLS,         "Protocols supported"},
    { TLV_IP_REACH_EXT,      "IPv4 External reachability"},
    { TLV_IDRP_INFO,         "Inter-Domain Information Type"},
    { TLV_IPADDR,            "IPv4 Interface address(es)"},
    { TLV_IPAUTH,            "IPv4 authentication (deprecated)"},
    { TLV_TE_ROUTER_ID,      "Traffic Engineering Router ID"},
    { TLV_EXT_IP_REACH,      "Extended IPv4 reachability"},
    { TLV_HOSTNAME,          "Hostname"},
    { TLV_SHARED_RISK_GROUP, "Shared Risk Link Group"},
    { TLV_NORTEL_PRIVATE1,   "Nortel Proprietary"},
    { TLV_NORTEL_PRIVATE2,   "Nortel Proprietary"},
    { TLV_RESTART_SIGNALING, "Restart Signaling"},
    { TLV_MT_IS_REACH,       "Multi Topology IS Reachability"},
    { TLV_MT_SUPPORTED,      "Multi Topology"},
    { TLV_IP6ADDR,           "IPv6 Interface address(es)"},
    { TLV_MT_IP_REACH,       "Multi-Topology IPv4 reachability"},
    { TLV_IP6_REACH,         "IPv6 reachability"},
    { TLV_MT_IP6_REACH,      "Multi-Topology IP6 reachability"},
    { TLV_PTP_ADJ,           "Point-to-point Adjacency State"},
    { 0, NULL }
};

#define SUBTLV_EXT_IS_REACH_ADMIN_GROUP           3
#define SUBTLV_EXT_IS_REACH_LINK_LOCAL_ID         4
#define SUBTLV_EXT_IS_REACH_LINK_REMOTE_ID        5
#define SUBTLV_EXT_IS_REACH_IPV4_INTF_ADDR        6
#define SUBTLV_EXT_IS_REACH_IPV4_NEIGHBOR_ADDR    8
#define SUBTLV_EXT_IS_REACH_MAX_LINK_BW           9
#define SUBTLV_EXT_IS_REACH_RESERVABLE_BW        10
#define SUBTLV_EXT_IS_REACH_UNRESERVED_BW        11
#define SUBTLV_EXT_IS_REACH_TE_METRIC            18
#define SUBTLV_EXT_IS_REACH_LINK_PROTECTION_TYPE 20
#define SUBTLV_EXT_IS_REACH_INTF_SW_CAP_DESCR    21

#define SUBTLV_IP_REACH_ADMIN_TAG32               1
#define SUBTLV_IP_REACH_ADMIN_TAG64               2

#define SUBTLV_AUTH_SIMPLE        1
#define SUBTLV_AUTH_MD5          54
#define SUBTLV_AUTH_MD5_LEN      16
#define SUBTLV_AUTH_PRIVATE     255

static struct tok isis_subtlv_auth_values[] = {
    { SUBTLV_AUTH_SIMPLE,	"simple text password"},
    { SUBTLV_AUTH_MD5,	        "HMAC-MD5 password"},
    { SUBTLV_AUTH_PRIVATE,	"Routing Domain private password"},
    { 0, NULL }
};

#define SUBTLV_IDRP_RES           0
#define SUBTLV_IDRP_LOCAL         1
#define SUBTLV_IDRP_ASN           2

static struct tok isis_subtlv_idrp_values[] = {
    { SUBTLV_IDRP_RES,         "Reserved"},
    { SUBTLV_IDRP_LOCAL,       "Routing-Domain Specific"},
    { SUBTLV_IDRP_ASN,         "AS Number Tag"},
    { 0, NULL}
};

#define ISIS_8BIT_MASK(x)                  ((x)&0xff)

#define ISIS_MASK_LSP_OL_BIT(x)            ((x)&0x4)
#define ISIS_MASK_LSP_ISTYPE_BITS(x)       ((x)&0x3)
#define ISIS_MASK_LSP_PARTITION_BIT(x)     ((x)&0x80)
#define ISIS_MASK_LSP_ATT_BITS(x)          ((x)&0x78)
#define ISIS_MASK_LSP_ATT_ERROR_BIT(x)     ((x)&0x40)
#define ISIS_MASK_LSP_ATT_EXPENSE_BIT(x)   ((x)&0x20)
#define ISIS_MASK_LSP_ATT_DELAY_BIT(x)     ((x)&0x10)
#define ISIS_MASK_LSP_ATT_DEFAULT_BIT(x)   ((x)&0x8)

#define ISIS_MASK_MTID(x)                  ((x)&0xfff)
#define ISIS_MASK_MTSUB(x)                 ((x)&0x8000)
#define ISIS_MASK_MTATT(x)                 ((x)&0x4000)

#define ISIS_MASK_TLV_EXT_IP_UPDOWN(x)     ((x)&0x80)
#define ISIS_MASK_TLV_EXT_IP_SUBTLV(x)     ((x)&0x40)

#define ISIS_MASK_TLV_IP6_UPDOWN(x)        ((x)&0x80)
#define ISIS_MASK_TLV_IP6_IE(x)            ((x)&0x40)
#define ISIS_MASK_TLV_IP6_SUBTLV(x)        ((x)&0x20)

#define ISIS_MASK_TLV_RESTART_RR(x)        ((x)&0x1)
#define ISIS_MASK_TLV_RESTART_RA(x)        ((x)&0x2)

#define ISIS_LSP_TLV_METRIC_SUPPORTED(x)   ((x)&0x80)
#define ISIS_LSP_TLV_METRIC_IE(x)          ((x)&0x40)
#define ISIS_LSP_TLV_METRIC_UPDOWN(x)      ((x)&0x80)
#define ISIS_LSP_TLV_METRIC_VALUE(x)	   ((x)&0x3f)

#define ISIS_MASK_TLV_SHARED_RISK_GROUP(x) ((x)&0x1)

static const char *isis_gmpls_link_prot_values[] = {
    "Extra",
    "Unprotected",
    "Shared",
    "Dedicated 1:1",
    "Dedicated 1+1",
    "Enhanced",
    "Reserved",
    "Reserved"
};

static struct tok isis_gmpls_sw_cap_values[] = {
    { 1,	"Packet-Switch Capable-1"},
    { 2,	"Packet-Switch Capable-2"},
    { 3,	"Packet-Switch Capable-3"},
    { 4,	"Packet-Switch Capable-4"},
    { 51,	"Layer-2 Switch Capable"},
    { 100,	"Time-Division-Multiplex"},
    { 150,	"Lambda-Switch Capable"},
    { 200,	"Fiber-Switch Capable"},
    { 0, NULL }
};

static struct tok isis_gmpls_lsp_enc_values[] = {
    { 1,    "Packet"},
    { 2,    "Ethernet V2/DIX"},
    { 3,    "ANSI PDH"},
    { 4,    "ETSI PDH"},
    { 5,    "SDH ITU-T G.707"},
    { 6,    "SONET ANSI T1.105"},
    { 7,    "Digital Wrapper"},
    { 8,    "Lambda (photonic)"},
    { 9,    "Fiber"},
    { 10,   "Ethernet 802.3"},
    { 11,   "FiberChannel"},
    { 0, NULL }
};

static struct tok isis_mt_values[] = {
    { 0,    "IPv4 unicast"},
    { 1,    "In-Band Management"},
    { 2,    "IPv6 unicast"},
    { 3,    "Multicast"},
    { 4095, "Development, Experimental or Proprietary"},
    { 0, NULL }
};

static struct tok isis_iih_circuit_type_values[] = {
    { 1,    "Level 1 only"},
    { 2,    "Level 2 only"},
    { 3,    "Level 1, Level 2"},
    { 0, NULL}
};

#define ISIS_LSP_TYPE_UNUSED0   0
#define ISIS_LSP_TYPE_LEVEL_1   1
#define ISIS_LSP_TYPE_UNUSED2   2
#define ISIS_LSP_TYPE_LEVEL_2   3

static struct tok isis_lsp_istype_values[] = {
    { ISIS_LSP_TYPE_UNUSED0,	"Unused 0x0 (invalid)"},
    { ISIS_LSP_TYPE_LEVEL_1,	"L1 IS"},
    { ISIS_LSP_TYPE_UNUSED2,	"Unused 0x2 (invalid)"},
    { ISIS_LSP_TYPE_LEVEL_2,	"L1L2 IS"},
    { 0, NULL }
};

static struct tok isis_nlpid_values[] = {
    { NLPID_CLNS,   "CLNS"},
    { NLPID_IP,     "IPv4"},
    { NLPID_IP6,    "IPv6"},
    { 0, NULL }
};

/*
 * Katz's point to point adjacency TLV uses codes to tell us the state of
 * the remote adjacency.  Enumerate them.
 */

#define ISIS_PTP_ADJ_UP   0
#define ISIS_PTP_ADJ_INIT 1
#define ISIS_PTP_ADJ_DOWN 2


static struct tok isis_ptp_adjancey_values[] = {
    { ISIS_PTP_ADJ_UP,    "Up" },
    { ISIS_PTP_ADJ_INIT,  "Initializing" },
    { ISIS_PTP_ADJ_DOWN,  "Down" },
    { 0, NULL}
};

struct isis_tlv_ptp_adj {
    u_char adjacency_state;
    u_char extd_local_circuit_id[4];
    u_char neighbor_sysid[SYSTEM_ID_LEN];
    u_char neighbor_extd_local_circuit_id[4];
};

static int osi_cksum(const u_char *, u_int);
static void esis_print(const u_char *, u_int);
static int isis_print(const u_char *, u_int);

struct isis_metric_block {
    u_char metric_default;
    u_char metric_delay;
    u_char metric_expense;
    u_char metric_error;
};

struct isis_tlv_is_reach {
    struct isis_metric_block isis_metric_block;
    u_char neighbor_nodeid[NODE_ID_LEN];
};

struct isis_tlv_es_reach {
    struct isis_metric_block isis_metric_block;
    u_char neighbor_sysid[SYSTEM_ID_LEN];
};

struct isis_tlv_ip_reach {
    struct isis_metric_block isis_metric_block;
    u_char prefix[4];
    u_char mask[4];
};

static struct tok isis_is_reach_virtual_values[] = {
    { 0,    "IsNotVirtual"},
    { 1,    "IsVirtual"},
    { 0, NULL }
};

struct isis_common_header {
    u_char nlpid;
    u_char fixed_len;
    u_char version;			/* Protocol version? */
    u_char id_length;
    u_char pdu_type;		        /* 3 MSbs are reserved */
    u_char pdu_version;			/* Packet format version? */
    u_char reserved;
    u_char max_area;
};

struct isis_iih_lan_header {
    u_char circuit_type;
    u_char source_id[SYSTEM_ID_LEN];
    u_char holding_time[2];
    u_char pdu_len[2];
    u_char priority;
    u_char lan_id[NODE_ID_LEN];
};

struct isis_iih_ptp_header {
    u_char circuit_type;
    u_char source_id[SYSTEM_ID_LEN];
    u_char holding_time[2];
    u_char pdu_len[2];
    u_char circuit_id;
};

struct isis_lsp_header {
    u_char pdu_len[2];
    u_char remaining_lifetime[2];
    u_char lsp_id[LSP_ID_LEN];
    u_char sequence_number[4];
    u_char checksum[2];
    u_char typeblock;
};

struct isis_csnp_header {
    u_char pdu_len[2];
    u_char source_id[NODE_ID_LEN];
    u_char start_lsp_id[LSP_ID_LEN];
    u_char end_lsp_id[LSP_ID_LEN];
};

struct isis_psnp_header {
    u_char pdu_len[2];
    u_char source_id[NODE_ID_LEN];
};

struct isis_tlv_lsp {
    u_char remaining_lifetime[2];
    u_char lsp_id[LSP_ID_LEN];
    u_char sequence_number[4];
    u_char checksum[2];
};


/* allocate space for the following string
 * xx.xxxx.xxxx.xxxx.xxxx.xxxx.xxxx
 * 32 bytes plus one termination byte */
static char *
print_nsap(register const u_char *cp, register int length)
{
	int i;
	static char nsap[33];
        char *pos = nsap;

        if (length==0) {
		*(pos) = '0';
                *(pos+1) = '\0';
                return (nsap);
        }

	for (i = 0; i < length; i++) {
		if (!TTEST2(*cp, 1))
			return (0);
		pos+=sprintf(pos, "%02x", *cp++);
		if (((i & 1) == 0) && (i + 1 < length)) {
			pos+=sprintf(pos, ".");
		}
	}
        *(pos) = '\0';
	return (nsap);
}

#define ISIS_COMMON_HEADER_SIZE (sizeof(struct isis_common_header))
#define ISIS_IIH_LAN_HEADER_SIZE (sizeof(struct isis_iih_lan_header))
#define ISIS_IIH_PTP_HEADER_SIZE (sizeof(struct isis_iih_ptp_header))
#define ISIS_LSP_HEADER_SIZE (sizeof(struct isis_lsp_header))
#define ISIS_CSNP_HEADER_SIZE (sizeof(struct isis_csnp_header))
#define ISIS_PSNP_HEADER_SIZE (sizeof(struct isis_psnp_header))

void isoclns_print(const u_char *p, u_int length, u_int caplen,
	      const u_char *esrc, const u_char *edst)
{
	u_char pdu_type;
	const struct isis_common_header *header;

	header = (const struct isis_common_header *)p;
	pdu_type = header->pdu_type & PDU_TYPE_MASK;

	if (caplen < 1) {
		printf("[|iso-clns] ");
		if (!eflag && esrc != NULL && edst != NULL)
			printf("%s > %s",
			       etheraddr_string(esrc),
			       etheraddr_string(edst));
		return;
	}

	switch (*p) {

	case NLPID_CLNS:
		(void)printf("CLNS(%d)", length);
		if (!eflag && esrc != NULL && edst != NULL)
			(void)printf(", %s > %s",
				     etheraddr_string(esrc),
				     etheraddr_string(edst));
		break;

	case NLPID_ESIS:
		(void)printf("ESIS(%u)", length);
		if (!eflag && esrc != NULL && edst != NULL)
			(void)printf(", %s > %s",
				     etheraddr_string(esrc),
				     etheraddr_string(edst));
		esis_print(p, length);
		return;

	case NLPID_ISIS:
		(void)printf("ISIS(%u)", length);
		if (!eflag && esrc != NULL && edst != NULL)
			(void)printf(", %s > %s",
			     etheraddr_string(esrc),
			     etheraddr_string(edst));
		if (!isis_print(p, length))
			default_print_unaligned(p, caplen);
		break;

	case NLPID_NULLNS:
		(void)printf("ISO NULLNS(%d)", length);
		if (!eflag && esrc != NULL && edst != NULL)
			(void)printf(", %s > %s",
				     etheraddr_string(esrc),
				     etheraddr_string(edst));
		break;

	default:
		(void)printf("CLNS %02x(%d)", p[0], length);
		if (!eflag && esrc != NULL && edst != NULL)
			(void)printf(", %s > %s",
				     etheraddr_string(esrc),
				     etheraddr_string(edst));
		if (caplen > 1)
			default_print_unaligned(p, caplen);
		break;
	}
}

#define	ESIS_REDIRECT	6
#define	ESIS_ESH	2
#define	ESIS_ISH	4

struct esis_hdr {
	u_char version;
	u_char reserved;
	u_char type;
	u_char tmo[2];
	u_char cksum[2];
};

static void
esis_print(const u_char *p, u_int length)
{
	const u_char *ep;
	u_int li;
	const struct esis_hdr *eh;

	if (length <= 2) {
		if (qflag)
			printf(" bad pkt!");
		else
			printf(" no header at all!");
		return;
	}
	li = p[1];
	eh = (const struct esis_hdr *) &p[2];
	ep = p + li;
	if (li > length) {
		if (qflag)
			printf(" bad pkt!");
		else
			printf(" LI(%d) > PDU size (%d)!", li, length);
		return;
	}
	if (li < sizeof(struct esis_hdr) + 2) {
		if (qflag)
			printf(" bad pkt!");
		else {
			printf(" too short for esis header %d:", li);
			while (--length != 0)
				printf("%02X", *p++);
		}
		return;
	}
	switch (eh->type & 0x1f) {

	case ESIS_REDIRECT:
		printf(" redirect");
		break;

	case ESIS_ESH:
		printf(" ESH");
		break;

	case ESIS_ISH:
		printf(" ISH");
		break;

	default:
		printf(" type %d", eh->type & 0x1f);
		break;
	}
	if (vflag && osi_cksum(p, li)) {
		printf(" bad cksum (got 0x%02x%02x)",
		       eh->cksum[1], eh->cksum[0]);
		default_print(p, length);
		return;
	}
	if (eh->version != 1) {
		printf(" unsupported version %d", eh->version);
		return;
	}
	p += sizeof(*eh) + 2;
	li -= sizeof(*eh) + 2;	/* protoid * li */

	switch (eh->type & 0x1f) {
	case ESIS_REDIRECT: {
		const u_char *dst, *snpa, *is;

		dst = p; p += *p + 1;
		if (p > snapend)
			return;
		printf("\n\t\t %s", isonsap_string(dst));
		snpa = p; p += *p + 1;
		is = p;   p += *p + 1;
		if (p > snapend)
			return;
		if (p > ep) {
			printf(" [bad li]");
			return;
		}
		if (is[0] == 0)
			printf(" > %s", etheraddr_string(&snpa[1]));
		else
			printf(" > %s", isonsap_string(is));
		li = ep - p;
		break;
	}
#if 0
	case ESIS_ESH:
		printf(" ESH");
		break;
#endif
	case ESIS_ISH: {
		const u_char *is;

		is = p; p += *p + 1;
		if (p > ep) {
			printf(" [bad li]");
			return;
		}
		if (p > snapend)
			return;
		if (!qflag)
			printf("\n\tNET: %s", print_nsap(is+1,*is));
		li = ep - p;
		break;
	}

	default:
		(void)printf(" len=%d", length);
		if (length && p < snapend) {
			length = snapend - p;
			default_print(p, length);
		}
		return;
	}
	if (vflag)
		while (p < ep && li) {
			u_int op, opli;
			const u_char *q;

			if (snapend - p < 2)
				return;
			if (li < 2) {
				printf(" bad opts/li");
				return;
			}
			op = *p++;
			opli = *p++;
			li -= 2;
			if (opli > li) {
				printf(" opt (%d) too long", op);
				return;
			}
			li -= opli;
			q = p;
			p += opli;
			if (snapend < p)
				return;
			if (op == 198 && opli == 2) {
				printf(" tmo=%d", q[0] * 256 + q[1]);
				continue;
			}
			printf (" %d:<", op);
			while (opli-- > 0)
				printf("%02x", *q++);
			printf (">");
		}
}

/* allocate space for the following string
 * xxxx.xxxx.xxxx
 * 14 bytes plus one termination byte */
static char *
isis_print_sysid(const u_char *cp, int sysid_len)
{
	int i;
	static char sysid[15];
        char *pos = sysid;

	for (i = 1; i <= sysid_len; i++) {
		if (!TTEST2(*cp, 1))
			return (0);
		pos+=sprintf(pos, "%02x", *cp++);
		if ((i==2)^(i==4)) {
			pos+=sprintf(pos, ".");
		}
	}
        *(pos) = '\0';
	return (sysid);
}


/* allocate space for the following string
 * xxxx.xxxx.xxxx.yy
 * 17 bytes plus one termination byte */
static char *
isis_print_nodeid(const u_char *cp)
{
	int i;
	static char nodeid[18];
        char *pos = nodeid;

	for (i = 1; i <= 7; i++) {
		if (!TTEST2(*cp, 1))
			return (0);
		pos+=sprintf(pos, "%02x", *cp++);
		if ((i & 1) == 0) {
			pos+=sprintf(pos, ".");
		}
	}
        *(pos) = '\0';
	return (nodeid);
}

/* allocate space for the following string
 * xxxx.xxxx.xxxx.yy-zz
 * 20 bytes plus one termination byte */
static char *
isis_print_lspid(const u_char *cp)
{
	int i;
	static char lspid[21];
        char *pos = lspid;

	for (i = 1; i <= 7; i++) {
		pos+=sprintf(pos, "%02x", *cp++);
		if ((i & 1) == 0)
			pos+=sprintf(pos, ".");
	}
	pos+=sprintf(pos, "-%02x", *cp);
        return (lspid);
}

/* print the 4-byte metric block which is common found in the old-style TLVs */

static int
isis_print_metric_block (const struct isis_metric_block *isis_metric_block)
{
    printf(", Default Metric: %d, %s",
           ISIS_LSP_TLV_METRIC_VALUE(isis_metric_block->metric_default),
           ISIS_LSP_TLV_METRIC_IE(isis_metric_block->metric_default) ? "External" : "Internal");
    if (!ISIS_LSP_TLV_METRIC_SUPPORTED(isis_metric_block->metric_delay))
        printf("\n\t\t  Delay Metric: %d, %s",
               ISIS_LSP_TLV_METRIC_VALUE(isis_metric_block->metric_delay),
               ISIS_LSP_TLV_METRIC_IE(isis_metric_block->metric_delay) ? "External" : "Internal");
    if (!ISIS_LSP_TLV_METRIC_SUPPORTED(isis_metric_block->metric_expense))
        printf("\n\t\t  Expense Metric: %d, %s",
               ISIS_LSP_TLV_METRIC_VALUE(isis_metric_block->metric_expense),
               ISIS_LSP_TLV_METRIC_IE(isis_metric_block->metric_expense) ? "External" : "Internal");
    if (!ISIS_LSP_TLV_METRIC_SUPPORTED(isis_metric_block->metric_error))
        printf("\n\t\t  Error Metric: %d, %s",
               ISIS_LSP_TLV_METRIC_VALUE(isis_metric_block->metric_error),
               ISIS_LSP_TLV_METRIC_IE(isis_metric_block->metric_error) ? "External" : "Internal");

    return(1); /* everything is ok */
}

static int
isis_print_tlv_ip_reach (const u_char *cp, int length)
{
	u_int bitmasks[33] = {
		0x00000000,
		0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
		0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
		0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
		0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
		0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
		0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
		0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
		0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
	};
	u_int mask;
	int prefix_len;
	const struct isis_tlv_ip_reach *tlv_ip_reach;

	tlv_ip_reach = (const struct isis_tlv_ip_reach *)cp;

	while (length > 0) {
		if (length < sizeof(*tlv_ip_reach)) {
			printf("short IPv4 reachability (%d vs %lu)", length,
			    (unsigned long)sizeof(*tlv_ip_reach));
			return (0);
		}

		if (!TTEST(*tlv_ip_reach))
		    return (0);

		mask = EXTRACT_32BITS(tlv_ip_reach->mask);
		prefix_len = 0;

                /* lets see if we can transform the mask into a prefixlen */
		while (prefix_len <= 33) {
			if (bitmasks[prefix_len++] == mask) {
				prefix_len--;
				break;
			}
		}

		/*
		 * 34 indicates no match -> must be a discontiguous netmask
		 * lets dump the mask, otherwise print the prefix_len
		 */
		if (prefix_len == 34)
			printf("\n\t\tIPv4 prefix: %s mask %s",
			       ipaddr_string((tlv_ip_reach->prefix)),
			       ipaddr_string((tlv_ip_reach->mask)));
		else
			printf("\n\t\tIPv4 prefix: %s/%u",
			       ipaddr_string((tlv_ip_reach->prefix)),
			       prefix_len);

		printf("\n\t\t  Default Metric: %02d, %s, Distribution: %s",
		    ISIS_LSP_TLV_METRIC_VALUE(tlv_ip_reach->isis_metric_block.metric_default),
		    ISIS_LSP_TLV_METRIC_IE(tlv_ip_reach->isis_metric_block.metric_default) ? "External" : "Internal",
		    ISIS_LSP_TLV_METRIC_UPDOWN(tlv_ip_reach->isis_metric_block.metric_default) ? "down" : "up");

		if (!ISIS_LSP_TLV_METRIC_SUPPORTED(tlv_ip_reach->isis_metric_block.metric_delay))
			printf("\n\t\t  Delay Metric: %02d, %s",
			    ISIS_LSP_TLV_METRIC_VALUE(tlv_ip_reach->isis_metric_block.metric_delay),
			    ISIS_LSP_TLV_METRIC_IE(tlv_ip_reach->isis_metric_block.metric_delay) ? "External" : "Internal");

		if (!ISIS_LSP_TLV_METRIC_SUPPORTED(tlv_ip_reach->isis_metric_block.metric_expense))
			printf("\n\t\t  Expense Metric: %02d, %s",
			    ISIS_LSP_TLV_METRIC_VALUE(tlv_ip_reach->isis_metric_block.metric_expense),
			    ISIS_LSP_TLV_METRIC_IE(tlv_ip_reach->isis_metric_block.metric_expense) ? "External" : "Internal");

		if (!ISIS_LSP_TLV_METRIC_SUPPORTED(tlv_ip_reach->isis_metric_block.metric_error))
			printf("\n\t\t  Error Metric: %02d, %s",
			    ISIS_LSP_TLV_METRIC_VALUE(tlv_ip_reach->isis_metric_block.metric_error),
			    ISIS_LSP_TLV_METRIC_IE(tlv_ip_reach->isis_metric_block.metric_error) ? "External" : "Internal");

		length -= sizeof(struct isis_tlv_ip_reach);
		tlv_ip_reach++;
	}
	return (1);
}

/*
 * this is the common IP-REACH subTLV decoder it is called
 * from various EXTD-IP REACH TLVs (135,235,236,237)
 */

static int
isis_print_ip_reach_subtlv (const u_char *tptr,int subt,int subl,const char *lf) {

        switch(subt) {
        case SUBTLV_IP_REACH_ADMIN_TAG32:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%s32-Bit Administrative tag: 0x%08x",
                   lf,
                   EXTRACT_32BITS(tptr));
            break;
        case SUBTLV_IP_REACH_ADMIN_TAG64:
            if (!TTEST2(*tptr,8))
                goto trunctlv;
            printf("%s64-Bit Administrative tag: 0x%08x%08x",
                   lf,
                   EXTRACT_32BITS(tptr),
                   EXTRACT_32BITS(tptr+4));
            break;
        default:
            printf("%sunknown subTLV, type %d, length %d",
                   lf,
                   subt,
                   subl);
            if(!print_unknown_data(tptr,"\n\t\t    ",
                                       subl))
                return(0);
            break;
        }
        return(1);

trunctlv:
    printf("%spacket exceeded snapshot",lf);
    return(0);
}

/*
 * this is the common IS-REACH subTLV decoder it is called
 * from various EXTD-IS REACH TLVs (22,24,222)
 */

static int
isis_print_is_reach_subtlv (const u_char *tptr,int subt,int subl,const char *lf) {

        int i,j;
        float bw; /* copy buffer for several subTLVs */

        switch(subt) {
        case SUBTLV_EXT_IS_REACH_ADMIN_GROUP:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%sAdministrative groups: 0x%08x",
                   lf,
                   EXTRACT_32BITS(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_LINK_LOCAL_ID:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%sLink Local Identifier: 0x%08x",
                   lf,
                   EXTRACT_32BITS(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_LINK_REMOTE_ID:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%sLink Remote Identifier: 0x%08x",
                   lf,
                   EXTRACT_32BITS(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_MAX_LINK_BW :
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            j = EXTRACT_32BITS(tptr);
            memcpy (&bw, &j, 4);
            printf("%sMaximum link bandwidth : %.3f Mbps",
                   lf,
                   bw*8/1000000 );
            break;
        case SUBTLV_EXT_IS_REACH_RESERVABLE_BW :
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            j = EXTRACT_32BITS(tptr);
            memcpy (&bw, &j, 4);
            printf("%sReservable link bandwidth: %.3f Mbps",
                   lf,
                   bw*8/1000000  );
            break;
        case SUBTLV_EXT_IS_REACH_UNRESERVED_BW :
            printf("%sUnreserved bandwidth:",lf);
            for (i = 0; i < 8; i++) {
                if (!TTEST2(*(tptr+i*4),4))
                    goto trunctlv;
                j = EXTRACT_32BITS(tptr);
                memcpy (&bw, &j, 4);
                printf("%s  priority level %d: %.3f Mbps",
                       lf,
                       i,
                       bw*8/1000000 );
            }
            break;
        case SUBTLV_EXT_IS_REACH_TE_METRIC:
            if (!TTEST2(*tptr,3))
                goto trunctlv;
            printf("%sTraffic Engineering Metric: %d",
                   lf,
                   EXTRACT_24BITS(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_IPV4_INTF_ADDR:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%sIPv4 interface address: %s",
                   lf,
                   ipaddr_string(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_IPV4_NEIGHBOR_ADDR:
            if (!TTEST2(*tptr,4))
                goto trunctlv;
            printf("%sIPv4 neighbor address: %s",
                   lf,
                   ipaddr_string(tptr));
            break;
        case SUBTLV_EXT_IS_REACH_LINK_PROTECTION_TYPE:
            if (!TTEST2(*tptr,2))
                goto trunctlv;
            i = 0;
            j = (ISIS_8BIT_MASK(*tptr)); /* fetch the typecode and make sure
                                            that no high-order LSBs are set */
            printf("%sLink Protection Type: %s",
                   lf,
                   (j) ? "" : "none" );
            /* scan through the bits until the typecode is zero */
            while(!j) {
                printf("%s", isis_gmpls_link_prot_values[i]);
                j=j>>1;
                if (j) /*any other bit set ?*/
                    printf(", ");
                i++;
            }
            printf(", Priority %u", *(tptr+1));
            break;
        case SUBTLV_EXT_IS_REACH_INTF_SW_CAP_DESCR:
            printf("%sInterface Switching Capability",lf);

            if (!TTEST2(*tptr,1))
                goto trunctlv;
            printf("%s  Interface Switching Capability:%s",
                   lf,
                   tok2str(isis_gmpls_sw_cap_values, "Unknown", *(tptr)));

            if (!TTEST2(*(tptr+1),1))
                goto trunctlv;
            printf(", LSP Encoding: %s",
                   tok2str(isis_gmpls_lsp_enc_values, "Unknown", *(tptr+1)));

            if (!TTEST2(*(tptr+2),2)) /* skip 2 res. bytes */
                goto trunctlv;

            printf("%s  Max LSP Bandwidth:",lf);
            for (i = 0; i < 8; i++) {
                if (!TTEST2(*(tptr+(i*4)+4),4))
                    goto trunctlv;
                j = EXTRACT_32BITS(tptr);
                memcpy (&bw, &j, 4);
                printf("%s    priority level %d: %.3f Mbps",
                       lf,
                       i,
                       bw*8/1000000 );
            }
            subl-=36;
            /* there is some optional stuff left to decode but this is as of yet
               not specified so just lets hexdump what is left */
            if(subl>0){
                if(!print_unknown_data(tptr,"\n\t\t    ",
                                           subl-36))
                    return(0);
            }
            break;
        case 250:
        case 251:
        case 252:
        case 253:
        case 254:
            printf("%sReserved for cisco specific extensions, type %d, length %d",
                   lf,
                   subt,
                   subl);
            break;
        case 255:
            printf("%sReserved for future expansion, type %d, length %d",
                   lf,
                   subt,
                   subl);
            break;
        default:
            printf("%sunknown subTLV, type %d, length %d",
                   lf,
                   subt,
                   subl);
            if(!print_unknown_data(tptr,"\n\t\t    ",
                                       subl))
                return(0);
            break;
        }
        return(1);

trunctlv:
    printf("%spacket exceeded snapshot",lf);
    return(0);
}


/*
 * isis_print
 * Decode IS-IS packets.  Return 0 on error.
 */

static int isis_print (const u_char *p, u_int length)
{
    const struct isis_common_header *header;

    const struct isis_iih_lan_header *header_iih_lan;
    const struct isis_iih_ptp_header *header_iih_ptp;
    const struct isis_lsp_header *header_lsp;
    const struct isis_csnp_header *header_csnp;
    const struct isis_psnp_header *header_psnp;

    const struct isis_tlv_lsp *tlv_lsp;
    const struct isis_tlv_ptp_adj *tlv_ptp_adj;
    const struct isis_tlv_is_reach *tlv_is_reach;
    const struct isis_tlv_es_reach *tlv_es_reach;

    u_char pdu_type, max_area, id_length, type, len, tmp, alen, lan_alen, prefix_len, subl, subt, tslen;
    const u_char *optr, *pptr, *tptr;
    u_short packet_len,pdu_len,time_remain;
    u_int i,j,bit_length,byte_length,metric,ra,rr;
    u_char prefix[4]; /* copy buffer for ipv4 prefixes */
#ifdef INET6
    u_char prefix6[16]; /* copy buffer for ipv6 prefixes */
#endif
    packet_len=length;
    optr = p; /* initialize the _o_riginal pointer to the packet start -
               need it for parsing the checksum TLV */
    header = (const struct isis_common_header *)p;
    TCHECK(*header);
    pptr = p+(ISIS_COMMON_HEADER_SIZE);
    header_iih_lan = (const struct isis_iih_lan_header *)pptr;
    header_iih_ptp = (const struct isis_iih_ptp_header *)pptr;
    header_lsp = (const struct isis_lsp_header *)pptr;
    header_csnp = (const struct isis_csnp_header *)pptr;
    header_psnp = (const struct isis_psnp_header *)pptr;

    /*
     * Sanity checking of the header.
     */
    if (header->nlpid != NLPID_ISIS) {
	printf(", coding error!");
	return (0);
    }

    if (header->version != ISIS_VERSION) {
	printf(", version %d packet not supported", header->version);
	return (0);
    }

    if ((header->id_length != SYSTEM_ID_LEN) && (header->id_length != 0)) {
	printf(", system ID length of %d is not supported",
	       header->id_length);
	return (0);
    }

    if (header->pdu_version != ISIS_VERSION) {
	printf(", version %d packet not supported", header->pdu_version);
	return (0);
    }

    max_area = header->max_area;
    switch(max_area) {
    case 0:
	max_area = 3;	 /* silly shit */
	break;
    case 255:
	printf(", bad packet -- 255 areas");
	return (0);
    default:
	break;
    }

    id_length = header->id_length;
    switch(id_length) {
    case 0:
        id_length = 6;	 /* silly shit again */
	break;
    case 1:              /* 1-8 are valid sys-ID lenghts */
    case 2:
    case 3:
    case 4:
    case 5:
    case 6:
    case 7:
    case 8:
        break;
    case 255:
        id_length = 0;   /* entirely useless */
	break;
    default:
	printf(", bad packet -- illegal sys-ID length (%u)", id_length);
	return (0);
	break;
    }

    printf("\n\thlen: %u, v: %u, pdu-v: %u, sys-id-len: %u (%u), max-area: %u (%u)",
           header->fixed_len,
           header->version,
           header->pdu_version,
	   id_length,
	   header->id_length,
           max_area,
           header->max_area);

    pdu_type=header->pdu_type;

    /* first lets see if we know the PDU name*/
    printf(", pdu-type: %s",
           tok2str(isis_pdu_values,
                   "unknown, type %d",
                   pdu_type));

    switch (pdu_type) {

    case L1_LAN_IIH:
    case L2_LAN_IIH:
	if (header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_LAN_HEADER_SIZE)) {
	    printf(", bogus fixed header length %u should be %lu",
		   header->fixed_len, (unsigned long)ISIS_IIH_LAN_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_iih_lan->pdu_len);
	if (packet_len>pdu_len) {
	  packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
	  length=pdu_len;
	}

	TCHECK(*header_iih_lan);
	printf("\n\t  source-id: %s,  holding time: %u, %s",
               isis_print_sysid(header_iih_lan->source_id,SYSTEM_ID_LEN),
               EXTRACT_16BITS(header_iih_lan->holding_time),
               tok2str(isis_iih_circuit_type_values,
                       "unknown circuit type 0x%02x",
                       header_iih_lan->circuit_type));

	printf("\n\t  lan-id:    %s, Priority: %u, PDU length: %u",
               isis_print_nodeid(header_iih_lan->lan_id),
               (header_iih_lan->priority) & PRIORITY_MASK,
               pdu_len);

	packet_len -= (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_LAN_HEADER_SIZE);
	pptr = p + (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_LAN_HEADER_SIZE);
	break;

    case PTP_IIH:
	if (header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_PTP_HEADER_SIZE)) {
	    printf(", bogus fixed header length %u should be %lu",
		   header->fixed_len, (unsigned long)ISIS_IIH_PTP_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_iih_ptp->pdu_len);
	if (packet_len>pdu_len) {
	  packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
	  length=pdu_len;
	}

	TCHECK(*header_iih_ptp);
	printf("\n\t  source-id: %s, holding time: %us, circuit-id: 0x%02x, %s, PDU length: %u",
               isis_print_sysid(header_iih_ptp->source_id,SYSTEM_ID_LEN),
               EXTRACT_16BITS(header_iih_ptp->holding_time),
               header_iih_ptp->circuit_id,
               tok2str(isis_iih_circuit_type_values,
                       "unknown circuit type 0x%02x",
                       header_iih_ptp->circuit_type),
               pdu_len);

	packet_len -= (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_PTP_HEADER_SIZE);
	pptr = p + (ISIS_COMMON_HEADER_SIZE+ISIS_IIH_PTP_HEADER_SIZE);
	break;

    case L1_LSP:
    case L2_LSP:
	if (header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_LSP_HEADER_SIZE)) {
	    printf(", bogus fixed header length %u should be %lu",
		   header->fixed_len, (unsigned long)ISIS_LSP_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_lsp->pdu_len);
	if (packet_len>pdu_len) {
	  packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
	  length=pdu_len;
	}

	TCHECK(*header_lsp);
	printf("\n\t  lsp-id: %s, seq: 0x%08x, lifetime: %5us",
               isis_print_lspid(header_lsp->lsp_id),
               EXTRACT_32BITS(header_lsp->sequence_number),
               EXTRACT_16BITS(header_lsp->remaining_lifetime));
        /* verify the checksum -
         * checking starts at the lsp-id field
         * which is 12 bytes after the packet start*/
	printf("\n\t  chksum: 0x%04x (%s), PDU length: %u",
               EXTRACT_16BITS(header_lsp->checksum),
               (osi_cksum(optr+12, length-12)) ? "incorrect" : "correct",
               pdu_len);

	printf(", %s", ISIS_MASK_LSP_OL_BIT(header_lsp->typeblock) ? "Overload bit set, " : "");

	if (ISIS_MASK_LSP_ATT_BITS(header_lsp->typeblock)) {
	    printf("%s", ISIS_MASK_LSP_ATT_DEFAULT_BIT(header_lsp->typeblock) ? "default " : "");
	    printf("%s", ISIS_MASK_LSP_ATT_DELAY_BIT(header_lsp->typeblock) ? "delay " : "");
	    printf("%s", ISIS_MASK_LSP_ATT_EXPENSE_BIT(header_lsp->typeblock) ? "expense " : "");
	    printf("%s", ISIS_MASK_LSP_ATT_ERROR_BIT(header_lsp->typeblock) ? "error " : "");
	    printf("ATT bit set, ");
	}
	printf("%s", ISIS_MASK_LSP_PARTITION_BIT(header_lsp->typeblock) ? "P bit set, " : "");
	printf("%s", tok2str(isis_lsp_istype_values,"Unknown(0x%x)",ISIS_MASK_LSP_ISTYPE_BITS(header_lsp->typeblock)));

	packet_len -= (ISIS_COMMON_HEADER_SIZE+ISIS_LSP_HEADER_SIZE);
	pptr = p + (ISIS_COMMON_HEADER_SIZE+ISIS_LSP_HEADER_SIZE);
	break;

    case L1_CSNP:
    case L2_CSNP:
	if (header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_CSNP_HEADER_SIZE)) {
	    printf(", bogus fixed header length %u should be %lu",
		   header->fixed_len, (unsigned long)ISIS_CSNP_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_csnp->pdu_len);
	if (packet_len>pdu_len) {
	  packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
	  length=pdu_len;
	}

	TCHECK(*header_csnp);
	printf("\n\t  source-id:    %s, PDU length: %u",
               isis_print_nodeid(header_csnp->source_id),
               pdu_len);
	printf("\n\t  start lsp-id: %s",
               isis_print_lspid(header_csnp->start_lsp_id));
	printf("\n\t  end lsp-id:   %s",
               isis_print_lspid(header_csnp->end_lsp_id));

	packet_len -= (ISIS_COMMON_HEADER_SIZE+ISIS_CSNP_HEADER_SIZE);
	pptr = p + (ISIS_COMMON_HEADER_SIZE+ISIS_CSNP_HEADER_SIZE);
        break;

    case L1_PSNP:
    case L2_PSNP:
	if (header->fixed_len != (ISIS_COMMON_HEADER_SIZE+ISIS_PSNP_HEADER_SIZE)) {
	    printf("- bogus fixed header length %u should be %lu",
		   header->fixed_len, (unsigned long)ISIS_PSNP_HEADER_SIZE);
	    return (0);
	}

	pdu_len=EXTRACT_16BITS(header_psnp->pdu_len);
	if (packet_len>pdu_len) {
	  packet_len=pdu_len; /* do TLV decoding as long as it makes sense */
	  length=pdu_len;
	}

	TCHECK(*header_psnp);
	printf("\n\t  source-id:    %s",
               isis_print_nodeid(header_psnp->source_id));

	packet_len -= (ISIS_COMMON_HEADER_SIZE+ISIS_PSNP_HEADER_SIZE);
	pptr = p + (ISIS_COMMON_HEADER_SIZE+ISIS_PSNP_HEADER_SIZE);
	break;

    default:
	if(!print_unknown_data(pptr,"\n\t  ",length))
	    return(0);
	return (0);
    }

    /*
     * Now print the TLV's.
     */

    while (packet_len >= 2) {
        if (pptr == snapend) {
	    return (1);
        }

	if (!TTEST2(*pptr, 2)) {
	    printf("\n\t\t packet exceeded snapshot (%ld) bytes",
		  (long)(pptr-snapend));
	    return (1);
	}
	type = *pptr++;
	len = *pptr++;
        tmp =len; /* copy temporary len & pointer to packet data */
        tptr = pptr;
	packet_len -= 2;
	if (len > packet_len) {
	    break;
	}

        /* first lets see if we know the TLVs name*/
	printf("\n\t    %s TLV #%u, length: %u",
               tok2str(isis_tlv_values,
                       "unknown",
                       type),
               type,
               len);

        /* now check if we have a decoder otherwise do a hexdump at the end*/
	switch (type) {
	case TLV_AREA_ADDR:
	    if (!TTEST2(*tptr, 1))
		goto trunctlv;
	    alen = *tptr++;
	    while (tmp && alen < tmp) {
		printf("\n\t\tArea address (%u): %s",
                       alen,
                       print_nsap(tptr, alen));
		tptr += alen;
		tmp -= alen + 1;
		if (tmp==0) /* if this is the last area address do not attemt a boundary check */
		  break;
		if (!TTEST2(*tptr, 1))
		    goto trunctlv;
		alen = *tptr++;
	    }
	    break;
	case TLV_ISNEIGH:
	    while (tmp >= ETHER_ADDR_LEN) {
            if (!TTEST2(*tptr, ETHER_ADDR_LEN))
		goto trunctlv;
            printf("\n\t\tIS Neighbor: %s",isis_print_sysid(tptr,ETHER_ADDR_LEN));
            tmp -= ETHER_ADDR_LEN;
            tptr += ETHER_ADDR_LEN;
	    }
	    break;

        case TLV_ISNEIGH_VARLEN:
            if (!TTEST2(*tptr, 1))
		goto trunctlv;
	    lan_alen = *tptr++; /* LAN adress length */
            tmp --;
            printf("\n\t\tLAN address length %u bytes ",lan_alen);
	    while (tmp >= lan_alen) {
            if (!TTEST2(*tptr, lan_alen))
		goto trunctlv;
            printf("\n\t\tIS Neighbor: %s",isis_print_sysid(tptr,lan_alen));
            tmp -= lan_alen;
            tptr +=lan_alen;
            }
            break;

	case TLV_PADDING:
	    break;

        case TLV_MT_IS_REACH:
            while (tmp>0) {
                if (!TTEST2(*tptr, 2))
		    goto trunctlv;
                printf("\n\t\t%s",
                       tok2str(isis_mt_values,
                               "Reserved for IETF Consensus",
                               ISIS_MASK_MTID(EXTRACT_16BITS(tptr))));

		printf(" Topology (0x%03x)",
                       ISIS_MASK_MTID(EXTRACT_16BITS(tptr)));
                tptr+=2;
                if (!TTEST2(*tptr, NODE_ID_LEN))
		    goto trunctlv;
		printf("\n\t\t  IS Neighbor: %s", isis_print_nodeid(tptr));
                tptr+=(NODE_ID_LEN);
                if (!TTEST2(*tptr, 3))
                    goto trunctlv;
                printf(", Metric: %d",EXTRACT_24BITS(tptr));
                tptr+=3;
                if (!TTEST2(*tptr, 1))
                    goto trunctlv;
                tslen=*(tptr++);
                printf(", %ssub-TLVs present",tslen ? "" : "no ");
                if (tslen) {
                    printf(" (%u)",tslen);
                    while (tslen>0) {
                        if (!TTEST2(*tptr,2))
                            goto trunctlv;
			subt=*(tptr++);
			subl=*(tptr++);
			if(!isis_print_is_reach_subtlv(tptr,subt,subl,"\n\t\t  "))
			    return(0);
			tptr+=subl;
			tslen-=(subl+2);
                        tmp-=(subl+2);
                    }
                }
                tmp-=(SYSTEM_ID_LEN+7);
            }
            break;

        case TLV_EXT_IS_REACH:
            while (tmp>0) {
                if (!TTEST2(*tptr, NODE_ID_LEN))
                    goto trunctlv;
		printf("\n\t\tIS Neighbor: %s", isis_print_nodeid(tptr));
                tptr+=(NODE_ID_LEN);

                if (!TTEST2(*tptr, 3))
                    goto trunctlv;
                printf(", Metric: %d",EXTRACT_24BITS(tptr));
                tptr+=3;

                if (!TTEST2(*tptr, 1))
                    goto trunctlv;
                tslen=*(tptr++); /* read out subTLV length */
                printf(", %ssub-TLVs present",tslen ? "" : "no ");
                if (tslen) {
                    printf(" (%u)",tslen);
                    while (tslen>0) {
                        if (!TTEST2(*tptr,2))
                            goto trunctlv;
			subt=*(tptr++);
			subl=*(tptr++);
			if(!isis_print_is_reach_subtlv(tptr,subt,subl,"\n\t\t  "))
			    return(0);
			tptr+=subl;
			tslen-=(subl+2);
                        tmp-=(subl+2);
                    }
                }
                tmp-=(SYSTEM_ID_LEN+5);
            }
            break;
        case TLV_IS_REACH:
	    if (!TTEST2(*tptr,1))  /* check if there is one byte left to read out the virtual flag */
		 goto trunctlv;
            printf("\n\t\t%s",
                   tok2str(isis_is_reach_virtual_values,
                           "bogus virtual flag 0x%02x",
                           *tptr++));
	    tlv_is_reach = (const struct isis_tlv_is_reach *)tptr;
            while (tmp >= sizeof(struct isis_tlv_is_reach)) {
		if (!TTEST(*tlv_is_reach))
		    goto trunctlv;
		printf("\n\t\tIS Neighbor: %s", isis_print_nodeid(tlv_is_reach->neighbor_nodeid));
                isis_print_metric_block(&tlv_is_reach->isis_metric_block);
		tmp -= sizeof(struct isis_tlv_is_reach);
		tlv_is_reach++;
	    }
            break;

        case TLV_ESNEIGH:
	    tlv_es_reach = (const struct isis_tlv_es_reach *)tptr;
            while (tmp >= sizeof(struct isis_tlv_es_reach)) {
		if (!TTEST(*tlv_es_reach))
		    goto trunctlv;
		printf("\n\t\tES Neighbor: %s",
                       isis_print_sysid(tlv_es_reach->neighbor_sysid,SYSTEM_ID_LEN));
                isis_print_metric_block(&tlv_es_reach->isis_metric_block);
		tmp -= sizeof(struct isis_tlv_es_reach);
		tlv_es_reach++;
	    }
            break;

            /* those two TLVs share the same format */
	case TLV_IP_REACH:
	case TLV_IP_REACH_EXT:
	    if (!isis_print_tlv_ip_reach(pptr, len))
		return (1);
	    break;

        case TLV_MT_IP_REACH:
	    while (tmp>0) {
                if (!TTEST2(*tptr, 2))
		    goto trunctlv;

                printf("\n\t\t%s",
                       tok2str(isis_mt_values,
                               "Reserved for IETF Consensus",
                               ISIS_MASK_MTID(EXTRACT_16BITS(tptr))));

		printf(" Topology (0x%03x)",
                       ISIS_MASK_MTID(EXTRACT_16BITS(tptr)));
                tptr+=2;

		memset (prefix, 0, 4);
		if (!TTEST2(*tptr, 4))
		    return (1);
	        metric = EXTRACT_32BITS(tptr);
		tptr+=4;

		if (!TTEST2(*tptr, 1)) /* fetch status byte */
		    return (1);
		j=*(tptr);
		bit_length = (*(tptr)++&0x3f);
		byte_length = (bit_length + 7) / 8; /* prefix has variable length encoding */

		if (!TTEST2(*tptr, byte_length))
		    return (1);
		memcpy(prefix,tptr,byte_length);
                tptr+=byte_length;
		printf("\n\t\tIPv4 prefix: %s/%d",
		       ipaddr_string(prefix),
		       bit_length);

		printf("\n\t\t  Metric: %u, Distribution: %s",
		       metric,
		       ISIS_MASK_TLV_EXT_IP_UPDOWN(j) ? "down" : "up");

		printf(", %ssub-TLVs present",
		       ISIS_MASK_TLV_EXT_IP_SUBTLV(j) ? "" : "no ");

		if (ISIS_MASK_TLV_EXT_IP_SUBTLV(j)) {
                    /* assume that one prefix can hold more
                       than one subTLV - therefore the first byte must reflect
                       the aggregate bytecount of the subTLVs for this prefix
                     */
		    if (!TTEST2(*tptr, 1))
		      return (1);
                    tslen=*(tptr++);
                    tmp--;
		    printf(" (%u)",tslen);   /* print out subTLV length */

                    while (tslen>0) {
                        if (!TTEST2(*tptr,2))
                            goto trunctlv;
			subt=*(tptr++);
			subl=*(tptr++);
			if(!isis_print_ip_reach_subtlv(tptr,subt,subl,"\n\t\t  "))
			    return(0);
			tptr+=subl;
			tslen-=(subl+2);
                        tmp-=(subl+2);
                    }
		}
		tmp-=(7+byte_length);
	    }
	    break;

	case TLV_EXT_IP_REACH:
	    while (tmp>0) {
		memset (prefix, 0, 4);
		if (!TTEST2(*tptr, 4))
		    return (1);
	        metric = EXTRACT_32BITS(tptr);
		tptr+=4;

		if (!TTEST2(*tptr, 1)) /* fetch status byte */
		    return (1);
		j=*(tptr);
		bit_length = (*(tptr)++&0x3f);
		byte_length = (bit_length + 7) / 8; /* prefix has variable length encoding */

		if (!TTEST2(*tptr, byte_length))
		    return (1);
		memcpy(prefix,tptr,byte_length);
                tptr+=byte_length;
		printf("\n\t\tIPv4 prefix: %s/%d",
		       ipaddr_string(prefix),
		       bit_length);

		printf("\n\t\t  Metric: %u, Distribution: %s",
		       metric,
		       ISIS_MASK_TLV_EXT_IP_UPDOWN(j) ? "down" : "up");

		printf(", %ssub-TLVs present",
		       ISIS_MASK_TLV_EXT_IP_SUBTLV(j) ? "" : "no ");

		if (ISIS_MASK_TLV_EXT_IP_SUBTLV(j)) {
                    /* assume that one prefix can hold more
                       than one subTLV - therefore the first byte must reflect
                       the aggregate bytecount of the subTLVs for this prefix
                     */
		    if (!TTEST2(*tptr, 1))
		      return (1);
                    tslen=*(tptr++);
                    tmp--;
		    printf(" (%u)",tslen);   /* print out subTLV length */

                    while (tslen>0) {
                        if (!TTEST2(*tptr,2))
                            goto trunctlv;
			subt=*(tptr++);
			subl=*(tptr++);
			if(!isis_print_ip_reach_subtlv(tptr,subt,subl,"\n\t\t  "))
			    return(0);
			tptr+=subl;
			tslen-=(subl+2);
                        tmp-=(subl+2);
                    }
		}
		tmp-=(5+byte_length);
	    }
	    break;

#ifdef INET6

	case TLV_IP6_REACH:
	    while (tmp>0) {
		if (!TTEST2(*tptr, 4))
		    return (1);
	        metric = EXTRACT_32BITS(tptr);
		tptr+=4;

		if (!TTEST2(*tptr, 2))
		    return (1);
		j=*(tptr++);
		bit_length = (*(tptr)++);
		byte_length = (bit_length + 7) / 8;
		if (!TTEST2(*tptr, byte_length))
		    return (1);

		memset(prefix6, 0, 16);
		memcpy(prefix6,tptr,byte_length);
                tptr+=byte_length;
		printf("\n\t\tIPv6 prefix: %s/%u",
		       ip6addr_string(prefix6),
		       bit_length);

		printf("\n\t\t  Metric: %u, %s, Distribution: %s, %ssub-TLVs present",
		    metric,
		    ISIS_MASK_TLV_IP6_IE(j) ? "External" : "Internal",
		    ISIS_MASK_TLV_IP6_UPDOWN(j) ? "down" : "up",
		    ISIS_MASK_TLV_IP6_SUBTLV(j) ? "" : "no ");

		if (ISIS_MASK_TLV_IP6_SUBTLV(j)) {
                    /* assume that one prefix can hold more
                       than one subTLV - therefore the first byte must reflect
                       the aggregate bytecount of the subTLVs for this prefix
                     */
		    if (!TTEST2(*tptr, 1))
		      return (1);
                    tslen=*(tptr++);
                    tmp--;
		    printf(" (%u)",tslen);   /* print out subTLV length */

                    while (tslen>0) {
                        if (!TTEST2(*tptr,2))
                            goto trunctlv;
			subt=*(tptr++);
			subl=*(tptr++);
			if(!isis_print_ip_reach_subtlv(tptr,subt,subl,"\n\t\t  "))
			    return(0);
			tptr+=subl;
			tslen-=(subl+2);
                        tmp-=(subl+2);
                    }
		}
		tmp-=(6+byte_length);
	    }

	    break;
#endif

#ifdef INET6
	case TLV_IP6ADDR:
	    while (tmp>0) {
		if (!TTEST2(*tptr, 16))
		    goto trunctlv;

                printf("\n\t\tIPv6 interface address: %s",
		       ip6addr_string(tptr));

		tptr += 16;
		tmp -= 16;
	    }
	    break;
#endif
	case TLV_AUTH:
	    if (!TTEST2(*tptr, 1))
		goto trunctlv;

            printf("\n\t\t%s: ",
                   tok2str(isis_subtlv_auth_values,
                           "unknown Authentication type 0x%02x",
                           *tptr));

	    switch (*tptr) {
	    case SUBTLV_AUTH_SIMPLE:
		for(i=1;i<len;i++) {
		    if (!TTEST2(*(tptr+i), 1))
			goto trunctlv;
		    printf("%c",*(tptr+i));
		}
		break;
	    case SUBTLV_AUTH_MD5:
		for(i=1;i<len;i++) {
		    if (!TTEST2(*(tptr+i), 1))
			goto trunctlv;
		    printf("%02x",*(tptr+i));
		}
		if (len != SUBTLV_AUTH_MD5_LEN+1)
		  printf(", (malformed subTLV) ");
		break;
	    case SUBTLV_AUTH_PRIVATE:
	    default:
		if(!print_unknown_data(tptr+1,"\n\t\t    ",len-1))
		    return(0);
		break;
	    }
	    break;

	case TLV_PTP_ADJ:
	    tlv_ptp_adj = (const struct isis_tlv_ptp_adj *)tptr;
	    if(tmp>=1) {
		if (!TTEST2(*tptr, 1))
		    goto trunctlv;
		printf("\n\t\tAdjacency State: %s",
		       tok2str(isis_ptp_adjancey_values, "0x%02x", *tptr));
		tmp--;
	    }
	    if(tmp>sizeof(tlv_ptp_adj->extd_local_circuit_id)) {
		if (!TTEST2(tlv_ptp_adj->extd_local_circuit_id,
                            sizeof(tlv_ptp_adj->extd_local_circuit_id)))
		    goto trunctlv;
		printf("\n\t\tExtended Local circuit ID: 0x%08x",
		       EXTRACT_32BITS(tlv_ptp_adj->extd_local_circuit_id));
		tmp-=sizeof(tlv_ptp_adj->extd_local_circuit_id);
	    }
	    if(tmp>=SYSTEM_ID_LEN) {
		if (!TTEST2(tlv_ptp_adj->neighbor_sysid, SYSTEM_ID_LEN))
		    goto trunctlv;
		printf("\n\t\tNeighbor SystemID: %s",
		       isis_print_sysid(tlv_ptp_adj->neighbor_sysid,SYSTEM_ID_LEN));
		tmp-=SYSTEM_ID_LEN;
	    }
	    if(tmp>=sizeof(tlv_ptp_adj->neighbor_extd_local_circuit_id)) {
		if (!TTEST2(tlv_ptp_adj->neighbor_extd_local_circuit_id,
                            sizeof(tlv_ptp_adj->neighbor_extd_local_circuit_id)))
		    goto trunctlv;
		printf("\n\t\tNeighbor Extended Local circuit ID: 0x%08x",
		       EXTRACT_32BITS(tlv_ptp_adj->neighbor_extd_local_circuit_id));
	    }
	    break;

	case TLV_PROTOCOLS:
	    printf("\n\t\tNLPID(s): ");
	    while (tmp>0) {
		if (!TTEST2(*(tptr), 1))
		    goto trunctlv;
		printf("%s",
                       tok2str(isis_nlpid_values,
                               "Unknown 0x%02x",
                               *tptr++));
		if (tmp>1) /* further NPLIDs ? - put comma */
		    printf(", ");
                tmp--;
	    }
	    break;

	case TLV_TE_ROUTER_ID:
	    if (!TTEST2(*pptr, 4))
		goto trunctlv;
	    printf("\n\t\tTraffic Engineering Router ID: %s", ipaddr_string(pptr));
	    break;

	case TLV_IPADDR:
	    while (tmp>0) {
		if (!TTEST2(*tptr, 4))
		    goto trunctlv;
		printf("\n\t\tIPv4 interface address: %s", ipaddr_string(tptr));
		tptr += 4;
		tmp -= 4;
	    }
	    break;

	case TLV_HOSTNAME:
	    printf("\n\t\tHostname: ");
	    while (tmp>0) {
		if (!TTEST2(*tptr, 1))
		    goto trunctlv;
		printf("%c",*tptr++);
                tmp--;
	    }
	    break;

	case TLV_SHARED_RISK_GROUP:
	    if (!TTEST2(*tptr, NODE_ID_LEN))
	      goto trunctlv;
	    printf("\n\t\tIS Neighbor: %s", isis_print_nodeid(tptr));
	    tptr+=(NODE_ID_LEN);
	    len-=(NODE_ID_LEN);

	    if (!TTEST2(*tptr, 1))
	      goto trunctlv;
	    printf(", %s", ISIS_MASK_TLV_SHARED_RISK_GROUP(*tptr++) ? "numbered" : "unnumbered");
	    len--;

	    if (!TTEST2(*tptr,4))
	      goto trunctlv;
	    printf("\n\t\tIPv4 interface address: %s", ipaddr_string(tptr));
	    tptr+=4;
	    len-=4;

	    if (!TTEST2(*tptr,4))
	      goto trunctlv;
	    printf("\n\t\tIPv4 neighbor address: %s", ipaddr_string(tptr));
	    tptr+=4;
	    len-=4;

	    while (tmp>0) {
	      if (!TTEST2(*tptr, 4))
		goto trunctlv;
	      printf("\n\t\tLink-ID: 0x%08x", EXTRACT_32BITS(tptr));
	      tptr+=4;
	      len-=4;
	    }
	    break;

	case TLV_LSP:
	    tlv_lsp = (const struct isis_tlv_lsp *)tptr;
	    while(tmp>0) {
		printf("\n\t\tlsp-id: %s",
                       isis_print_nodeid(tlv_lsp->lsp_id));
		if (!TTEST((tlv_lsp->lsp_id)[NODE_ID_LEN]))
		    goto trunctlv;
		printf("-%02x",(tlv_lsp->lsp_id)[NODE_ID_LEN]);
		if (!TTEST2(tlv_lsp->sequence_number, 4))
		    goto trunctlv;
		printf(", seq: 0x%08x",EXTRACT_32BITS(tlv_lsp->sequence_number));
		if (!TTEST2(tlv_lsp->remaining_lifetime, 2))
		    goto trunctlv;
		printf(", lifetime: %5ds",EXTRACT_16BITS(tlv_lsp->remaining_lifetime));
		if (!TTEST2(tlv_lsp->checksum, 2))
		    goto trunctlv;
		printf(", chksum: 0x%04x",EXTRACT_16BITS(tlv_lsp->checksum));
		tmp-=sizeof(struct isis_tlv_lsp);
		tlv_lsp++;
	    }
	    break;

	case TLV_CHECKSUM:
	    if (!TTEST2(*tptr, 2))
		goto trunctlv;
	    printf("\n\t\tchecksum: 0x%04x (%s)",
		   EXTRACT_16BITS(tptr),
                   (osi_cksum(optr, length)) ? "incorrect" : "correct");
	    break;

	case TLV_MT_SUPPORTED:
	    while (tmp>1) {
		/* length can only be a multiple of 2, otherwise there is
		   something broken -> so decode down until length is 1 */
		if (tmp!=1) {
		    if (!TTEST2(*tptr, 2))
			goto trunctlv;
                    printf("\n\t\t%s",
                           tok2str(isis_mt_values,
                                   "Reserved for IETF Consensus",
                                   ISIS_MASK_MTID(EXTRACT_16BITS(tptr))));

		    printf(" Topology (0x%03x)%s%s",
			   ISIS_MASK_MTID(EXTRACT_16BITS(tptr)),
			   ISIS_MASK_MTSUB(EXTRACT_16BITS(tptr)) ? "" : ", no sub-TLVs present",
			   ISIS_MASK_MTATT(EXTRACT_16BITS(tptr)) ? ", ATT bit set" : "" );
		} else {
		    printf("\n\t\tmalformed MT-ID");
		    break;
		}
		tmp-=2;
		tptr+=2;
	    }
	    break;

	case TLV_RESTART_SIGNALING:
            if (!TTEST2(*tptr, 3))
                goto trunctlv;
	    rr = ISIS_MASK_TLV_RESTART_RR(*tptr);
	    ra = ISIS_MASK_TLV_RESTART_RA(*tptr);
	    tptr++;
	    time_remain = EXTRACT_16BITS(tptr);
	    printf("\n\t\tRestart Request bit %s, Restart Acknowledgement bit %s\n\t\tRemaining holding time: %us",
		   rr ? "set" : "clear", ra ? "set" : "clear", time_remain);
	    break;

        case TLV_IDRP_INFO:
            if (!TTEST2(*tptr, 1))
                goto trunctlv;
            printf("\n\t\tInter-Domain Information Type: %s",
                   tok2str(isis_subtlv_idrp_values,
                           "Unknown (0x%02x)",
                           *tptr));
            switch (*tptr++) {
            case SUBTLV_IDRP_ASN:
                if (!TTEST2(*tptr, 2)) /* fetch AS number */
                    goto trunctlv;
                printf("AS Number: %u",EXTRACT_16BITS(tptr));
                break;
            case SUBTLV_IDRP_LOCAL:
            case SUBTLV_IDRP_RES:
            default:
                if(!print_unknown_data(tptr,"\n\t\t",len-1))
                    return(0);
                break;
            }
            break;

        case TLV_LSP_BUFFERSIZE:
            if (!TTEST2(*tptr, 2))
                goto trunctlv;
                printf("LSP Buffersize: %u",EXTRACT_16BITS(tptr));
            break;

        case TLV_PART_DIS:
            while (tmp >= SYSTEM_ID_LEN) {
            if (!TTEST2(*tptr, SYSTEM_ID_LEN))
                goto trunctlv;
            printf("%s",isis_print_sysid(tptr,SYSTEM_ID_LEN));
            tptr+=SYSTEM_ID_LEN;
            tmp-=SYSTEM_ID_LEN;
            }
            break;

        case TLV_PREFIX_NEIGH:
            if (!TTEST2(*tptr, sizeof(struct isis_metric_block)))
                goto trunctlv;
            printf("Metric Block");
            isis_print_metric_block((const struct isis_metric_block *)tptr);
            tptr+=sizeof(struct isis_metric_block);
            tmp-=sizeof(struct isis_metric_block);

            while(tmp>0) {
                if (!TTEST2(*tptr, 1))
                    goto trunctlv;
                prefix_len=*tptr++; /* read out prefix length in semioctets*/
                tmp--;
                if (!TTEST2(*tptr, prefix_len/2))
                    goto trunctlv;
                printf("\n\t\tAddress: %s/%u",
                       print_nsap(tptr,prefix_len/2),
                       prefix_len*4);
                tptr+=prefix_len/2;
                tmp-=prefix_len/2;
            }
            break;

            /*
             * FIXME those are the defined TLVs that lack a decoder
             * you are welcome to contribute code ;-)
             */

        case TLV_IS_ALIAS_ID:
        case TLV_DECNET_PHASE4:
        case TLV_LUCENT_PRIVATE:
        case TLV_IPAUTH:
        case TLV_NORTEL_PRIVATE1:
        case TLV_NORTEL_PRIVATE2:
        case TLV_MT_IP6_REACH:

	default:
	    if(!print_unknown_data(pptr,"\n\t\t",len))
	        return(0);
	    break;
	}

	pptr += len;
	packet_len -= len;
    }

    if (packet_len != 0) {
	printf("\n\t\t %d straggler bytes", packet_len);
    }
    return (1);

trunc:
    fputs("[|isis]", stdout);
    return (1);

trunctlv:
    printf("\n\t\t packet exceeded snapshot");
    return(1);
}

/*
 * Verify the checksum.  See 8473-1, Appendix C, section C.4.
 */

static int
osi_cksum(const u_char *tptr, u_int len)
{
	int32_t c0 = 0, c1 = 0;

	while ((int)--len >= 0) {
		c0 += *tptr++;
		c0 %= 255;
		c1 += c0;
		c1 %= 255;
	}
	return (c0 | c1);
}