path: root/print-ldp.c

/*
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code
 * distributions retain the above copyright notice and this paragraph
 * in its entirety, and (2) distributions including binary code include
 * the above copyright notice and this paragraph in its entirety in
 * the documentation or other materials provided with the distribution.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 *
 * Original code by Hannes Gredler (hannes@juniper.net)
 *  and Steinar Haug (sthaug@nethelp.no)
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/tcpdump/print-ldp.c,v 1.20 2006-06-23 02:03:09 hannes Exp $";
#endif

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

#include <tcpdump-stdinc.h>

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

#include "interface.h"
#include "decode_prefix.h"
#include "extract.h"
#include "addrtoname.h"

#include "l2vpn.h"
#include "af.h"

/*
 * ldp common header
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |  Version                      |         PDU Length            |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                         LDP Identifier                        |
 * +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *
 */

struct ldp_common_header {
    u_int8_t version[2];
    u_int8_t pdu_length[2];
    u_int8_t lsr_id[4];
    u_int8_t label_space[2];
};

#define LDP_VERSION 1

/*
 * ldp message header
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |U|   Message Type              |      Message Length           |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Message ID                                |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                                                               |
 * +                                                               +
 * |                     Mandatory Parameters                      |
 * +                                                               +
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                                                               |
 * +                                                               +
 * |                     Optional Parameters                       |
 * +                                                               +
 * |                                                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

struct ldp_msg_header {
    u_int8_t type[2];
    u_int8_t length[2];
    u_int8_t id[4];
};

#define	LDP_MASK_MSG_TYPE(x)  ((x)&0x7fff) 
#define	LDP_MASK_U_BIT(x)     ((x)&0x8000) 

#define	LDP_MSG_NOTIF                0x0001
#define	LDP_MSG_HELLO                0x0100
#define	LDP_MSG_INIT                 0x0200
#define	LDP_MSG_KEEPALIVE            0x0201
#define	LDP_MSG_ADDRESS              0x0300
#define	LDP_MSG_ADDRESS_WITHDRAW     0x0301
#define	LDP_MSG_LABEL_MAPPING        0x0400
#define	LDP_MSG_LABEL_REQUEST        0x0401
#define	LDP_MSG_LABEL_WITHDRAW       0x0402
#define	LDP_MSG_LABEL_RELEASE        0x0403
#define	LDP_MSG_LABEL_ABORT_REQUEST  0x0404

#define	LDP_VENDOR_PRIVATE_MIN       0x3e00
#define	LDP_VENDOR_PRIVATE_MAX       0x3eff
#define	LDP_EXPERIMENTAL_MIN         0x3f00
#define	LDP_EXPERIMENTAL_MAX         0x3fff

static const struct tok ldp_msg_values[] = {
    { LDP_MSG_NOTIF,	             "Notification" },
    { LDP_MSG_HELLO,	             "Hello" },
    { LDP_MSG_INIT,	             "Initialization" },
    { LDP_MSG_KEEPALIVE,             "Keepalive" },
    { LDP_MSG_ADDRESS,	             "Address" },
    { LDP_MSG_ADDRESS_WITHDRAW,	     "Address Withdraw" },
    { LDP_MSG_LABEL_MAPPING,	     "Label Mapping" },
    { LDP_MSG_LABEL_REQUEST,	     "Label Request" },
    { LDP_MSG_LABEL_WITHDRAW,	     "Label Withdraw" },
    { LDP_MSG_LABEL_RELEASE,	     "Label Release" },
    { LDP_MSG_LABEL_ABORT_REQUEST,   "Label Abort Request" },
    { 0, NULL}
};

#define	LDP_MASK_TLV_TYPE(x)  ((x)&0x3fff) 
#define	LDP_MASK_F_BIT(x) ((x)&0x4000) 

#define	LDP_TLV_FEC                  0x0100
#define	LDP_TLV_ADDRESS_LIST         0x0101
#define LDP_TLV_ADDRESS_LIST_AFNUM_LEN 2
#define	LDP_TLV_HOP_COUNT            0x0103
#define	LDP_TLV_PATH_VECTOR          0x0104
#define	LDP_TLV_GENERIC_LABEL        0x0200
#define	LDP_TLV_ATM_LABEL            0x0201
#define	LDP_TLV_FR_LABEL             0x0202
#define	LDP_TLV_STATUS               0x0300
#define	LDP_TLV_EXTD_STATUS          0x0301
#define	LDP_TLV_RETURNED_PDU         0x0302
#define	LDP_TLV_RETURNED_MSG         0x0303
#define	LDP_TLV_COMMON_HELLO         0x0400
#define	LDP_TLV_IPV4_TRANSPORT_ADDR  0x0401
#define	LDP_TLV_CONFIG_SEQ_NUMBER    0x0402
#define	LDP_TLV_IPV6_TRANSPORT_ADDR  0x0403
#define	LDP_TLV_COMMON_SESSION       0x0500
#define	LDP_TLV_ATM_SESSION_PARM     0x0501
#define	LDP_TLV_FR_SESSION_PARM      0x0502
#define LDP_TLV_FT_SESSION	     0x0503
#define	LDP_TLV_LABEL_REQUEST_MSG_ID 0x0600
#define LDP_TLV_MTU                  0x0601 /* rfc 3988 */

static const struct tok ldp_tlv_values[] = {
    { LDP_TLV_FEC,	             "FEC" },
    { LDP_TLV_ADDRESS_LIST,          "Address List" },
    { LDP_TLV_HOP_COUNT,             "Hop Count" },
    { LDP_TLV_PATH_VECTOR,           "Path Vector" },
    { LDP_TLV_GENERIC_LABEL,         "Generic Label" },
    { LDP_TLV_ATM_LABEL,             "ATM Label" },
    { LDP_TLV_FR_LABEL,              "Frame-Relay Label" },
    { LDP_TLV_STATUS,                "Status" },
    { LDP_TLV_EXTD_STATUS,           "Extended Status" },
    { LDP_TLV_RETURNED_PDU,          "Returned PDU" },
    { LDP_TLV_RETURNED_MSG,          "Returned Message" },
    { LDP_TLV_COMMON_HELLO,          "Common Hello Parameters" },
    { LDP_TLV_IPV4_TRANSPORT_ADDR,   "IPv4 Transport Address" },
    { LDP_TLV_CONFIG_SEQ_NUMBER,     "Configuration Sequence Number" },
    { LDP_TLV_IPV6_TRANSPORT_ADDR,   "IPv6 Transport Address" },
    { LDP_TLV_COMMON_SESSION,        "Common Session Parameters" },
    { LDP_TLV_ATM_SESSION_PARM,      "ATM Session Parameters" },
    { LDP_TLV_FR_SESSION_PARM,       "Frame-Relay Session Parameters" },
    { LDP_TLV_FT_SESSION,            "Fault-Tolerant Session Parameters" },
    { LDP_TLV_LABEL_REQUEST_MSG_ID,  "Label Request Message ID" },
    { LDP_TLV_MTU,                   "MTU" },
    { 0, NULL}
};

#define LDP_FEC_WILDCARD	0x01
#define LDP_FEC_PREFIX		0x02
#define LDP_FEC_HOSTADDRESS	0x03
/* From RFC 4906; should probably be updated to RFC 4447 (e.g., VC -> PW) */
#define LDP_FEC_MARTINI_VC	0x80

static const struct tok ldp_fec_values[] = {
    { LDP_FEC_WILDCARD,		"Wildcard" },
    { LDP_FEC_PREFIX,		"Prefix" },
    { LDP_FEC_HOSTADDRESS,	"Host address" },
    { LDP_FEC_MARTINI_VC,	"Martini VC" },
    { 0, NULL}
};

#define LDP_FEC_MARTINI_IFPARM_MTU  0x01
#define LDP_FEC_MARTINI_IFPARM_DESC 0x03
#define LDP_FEC_MARTINI_IFPARM_VCCV 0x0c

static const struct tok ldp_fec_martini_ifparm_values[] = {
    { LDP_FEC_MARTINI_IFPARM_MTU, "MTU" },
    { LDP_FEC_MARTINI_IFPARM_DESC, "Description" },
    { LDP_FEC_MARTINI_IFPARM_VCCV, "VCCV" },
    { 0, NULL}
};

/* draft-ietf-pwe3-vccv-04.txt */
static const struct tok ldp_fec_martini_ifparm_vccv_cc_values[] = {
    { 0x01, "PWE3 control word" },
    { 0x02, "MPLS Router Alert Label" },
    { 0x04, "MPLS inner label TTL = 1" },
    { 0, NULL}
};

/* draft-ietf-pwe3-vccv-04.txt */
static const struct tok ldp_fec_martini_ifparm_vccv_cv_values[] = {
    { 0x01, "ICMP Ping" },
    { 0x02, "LSP Ping" },
    { 0x04, "BFD" },
    { 0, NULL}
};

int ldp_msg_print(register const u_char *);
int ldp_tlv_print(register const u_char *);
   
/* 
 * ldp tlv header
 *
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |U|F|        Type               |            Length             |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                                                               |
 * |                             Value                             |
 * ~                                                               ~
 * |                                                               |
 * |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                               |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */

#define TLV_TCHECK(minlen) \
    TCHECK2(*tptr, minlen); if (tlv_tlen < minlen) goto badtlv;

int
ldp_tlv_print(register const u_char *tptr) {

    struct ldp_tlv_header {
        u_int8_t type[2];
        u_int8_t length[2];
    };

    const struct ldp_tlv_header *ldp_tlv_header;
    u_short tlv_type,tlv_len,tlv_tlen,af,ft_flags;
    u_char fec_type;
    u_int ui,vc_info_len, vc_info_tlv_type, vc_info_tlv_len,idx;
    char buf[100];
    int i;

    ldp_tlv_header = (const struct ldp_tlv_header *)tptr;    
    tlv_len=EXTRACT_16BITS(ldp_tlv_header->length);
    tlv_tlen=tlv_len;
    tlv_type=LDP_MASK_TLV_TYPE(EXTRACT_16BITS(ldp_tlv_header->type));

    /* FIXME vendor private / experimental check */
    printf("\n\t    %s TLV (0x%04x), length: %u, Flags: [%s and %s forward if unknown]",
           tok2str(ldp_tlv_values,
                   "Unknown",
                   tlv_type),
           tlv_type,
           tlv_len,
           LDP_MASK_U_BIT(EXTRACT_16BITS(&ldp_tlv_header->type)) ? "continue processing" : "ignore",
           LDP_MASK_F_BIT(EXTRACT_16BITS(&ldp_tlv_header->type)) ? "do" : "don't");

    tptr+=sizeof(struct ldp_tlv_header);

    switch(tlv_type) {

    case LDP_TLV_COMMON_HELLO:
        TLV_TCHECK(4);
        printf("\n\t      Hold Time: %us, Flags: [%s Hello%s]",
               EXTRACT_16BITS(tptr),
               (EXTRACT_16BITS(tptr+2)&0x8000) ? "Targeted" : "Link",
               (EXTRACT_16BITS(tptr+2)&0x4000) ? ", Request for targeted Hellos" : "");
        break;

    case LDP_TLV_IPV4_TRANSPORT_ADDR:
        TLV_TCHECK(4);
        printf("\n\t      IPv4 Transport Address: %s", ipaddr_string(tptr));
        break;
#ifdef INET6
    case LDP_TLV_IPV6_TRANSPORT_ADDR:
        TLV_TCHECK(16);
        printf("\n\t      IPv6 Transport Address: %s", ip6addr_string(tptr));
        break;
#endif
    case LDP_TLV_CONFIG_SEQ_NUMBER:
        TLV_TCHECK(4);
        printf("\n\t      Sequence Number: %u", EXTRACT_32BITS(tptr));
        break;

    case LDP_TLV_ADDRESS_LIST:
        TLV_TCHECK(LDP_TLV_ADDRESS_LIST_AFNUM_LEN);
	af = EXTRACT_16BITS(tptr);
	tptr+=LDP_TLV_ADDRESS_LIST_AFNUM_LEN;
        tlv_tlen -= LDP_TLV_ADDRESS_LIST_AFNUM_LEN;
	printf("\n\t      Address Family: %s, addresses",
               tok2str(af_values, "Unknown (%u)", af));
        switch (af) {
        case AFNUM_INET:
	    while(tlv_tlen >= sizeof(struct in_addr)) {
		TCHECK2(*tptr, sizeof(struct in_addr));
		printf(" %s",ipaddr_string(tptr));
		tlv_tlen-=sizeof(struct in_addr);
		tptr+=sizeof(struct in_addr);                
	    }
            break;
#ifdef INET6
        case AFNUM_INET6:
	    while(tlv_tlen >= sizeof(struct in6_addr)) {
		TCHECK2(*tptr, sizeof(struct in6_addr));
		printf(" %s",ip6addr_string(tptr));
		tlv_tlen-=sizeof(struct in6_addr);
		tptr+=sizeof(struct in6_addr);                
	    }
            break;
#endif
        default:
            /* unknown AF */
            break;
        }
	break;

    case LDP_TLV_COMMON_SESSION:
	TLV_TCHECK(8);
	printf("\n\t      Version: %u, Keepalive: %us, Flags: [Downstream %s, Loop Detection %s]",
	       EXTRACT_16BITS(tptr), EXTRACT_16BITS(tptr+2),
	       (EXTRACT_16BITS(tptr+6)&0x8000) ? "On Demand" : "Unsolicited",
	       (EXTRACT_16BITS(tptr+6)&0x4000) ? "Enabled" : "Disabled"
	       );
	break;

    case LDP_TLV_FEC:
        TLV_TCHECK(1);
        fec_type = *tptr;
	printf("\n\t      %s FEC (0x%02x)",
	       tok2str(ldp_fec_values, "Unknown", fec_type),
	       fec_type);

	tptr+=1;
	tlv_tlen-=1;
	switch(fec_type) {

	case LDP_FEC_WILDCARD:
	    break;
	case LDP_FEC_PREFIX:
	    TLV_TCHECK(2);
	    af = EXTRACT_16BITS(tptr);
	    tptr+=LDP_TLV_ADDRESS_LIST_AFNUM_LEN;
	    tlv_tlen-=LDP_TLV_ADDRESS_LIST_AFNUM_LEN;
	    if (af == AFNUM_INET) {
		i=decode_prefix4(tptr,tlv_tlen,buf,sizeof(buf));
		if (i == -2)
		    goto trunc;
		if (i == -3)
		    printf(": IPv4 prefix (goes past end of TLV)");
		else if (i == -1)
		    printf(": IPv4 prefix (invalid length)");
		else
		    printf(": IPv4 prefix %s",buf);
	    }
#ifdef INET6
	    else if (af == AFNUM_INET6) {
		i=decode_prefix6(tptr,tlv_tlen,buf,sizeof(buf));
		if (i == -2)
		    goto trunc;
		if (i == -3)
		    printf(": IPv4 prefix (goes past end of TLV)");
		else if (i == -1)
		    printf(": IPv6 prefix (invalid length)");
		else
		    printf(": IPv6 prefix %s",buf);
	    }
#endif
	    else
		printf(": Address family %u prefix", af);
	    break;
	case LDP_FEC_HOSTADDRESS:
	    break;
	case LDP_FEC_MARTINI_VC:
            /*
	     * According to RFC 4908, the VC info Length field can be zero,
	     * in which case not only are there no interface parameters,
	     * there's no VC ID.
	     */
            TLV_TCHECK(7);
            vc_info_len = *(tptr+2);

            if (vc_info_len == 0) {
                printf(": %s, %scontrol word, group-ID %u, VC-info-length: %u",
                       tok2str(l2vpn_encaps_values, "Unknown", EXTRACT_16BITS(tptr)&0x7fff),
                       EXTRACT_16BITS(tptr)&0x8000 ? "" : "no ",
                       EXTRACT_32BITS(tptr+3),
                       vc_info_len);
                break;
            }

            /* Make sure we have the VC ID as well */
            TLV_TCHECK(11);
	    printf(": %s, %scontrol word, group-ID %u, VC-ID %u, VC-info-length: %u",
		   tok2str(l2vpn_encaps_values, "Unknown", EXTRACT_16BITS(tptr)&0x7fff),
		   EXTRACT_16BITS(tptr)&0x8000 ? "" : "no ",
                   EXTRACT_32BITS(tptr+3),
		   EXTRACT_32BITS(tptr+7),
                   vc_info_len);
            if (vc_info_len < 4)
                goto trunc; /* minimum 4, for the VC ID */
            vc_info_len -= 4; /* subtract out the VC ID, giving the length of the interface parameters */

            /* Skip past the fixed information and the VC ID */
            tptr+=11;
            tlv_tlen-=11;
            TLV_TCHECK(vc_info_len);

            while (vc_info_len > 2) {
                vc_info_tlv_type = *tptr;
                vc_info_tlv_len = *(tptr+1);
                if (vc_info_tlv_len < 2)
                    break;
                if (vc_info_len < vc_info_tlv_len)
                    break;

                printf("\n\t\tInterface Parameter: %s (0x%02x), len %u",
                       tok2str(ldp_fec_martini_ifparm_values,"Unknown",vc_info_tlv_type),
                       vc_info_tlv_type,
                       vc_info_tlv_len);

                switch(vc_info_tlv_type) {
                case LDP_FEC_MARTINI_IFPARM_MTU:
                    printf(": %u",EXTRACT_16BITS(tptr+2));
                    break;

                case LDP_FEC_MARTINI_IFPARM_DESC:
                    printf(": ");
                    for (idx = 2; idx < vc_info_tlv_len; idx++)
                        safeputchar(*(tptr+idx));
                    break;

                case LDP_FEC_MARTINI_IFPARM_VCCV:
                    printf("\n\t\t  Control Channels (0x%02x) = [%s]",
                           *(tptr+2),
                           bittok2str(ldp_fec_martini_ifparm_vccv_cc_values,"none",*(tptr+2)));
                    printf("\n\t\t  CV Types (0x%02x) = [%s]",
                           *(tptr+3),
                           bittok2str(ldp_fec_martini_ifparm_vccv_cv_values,"none",*(tptr+3)));
                    break;

                default:
                    print_unknown_data(tptr+2,"\n\t\t  ",vc_info_tlv_len-2);
                    break;
                }

                vc_info_len -= vc_info_tlv_len;
                tptr += vc_info_tlv_len;
            }
	    break;
	}

	break;

    case LDP_TLV_GENERIC_LABEL:
	TLV_TCHECK(4);
	printf("\n\t      Label: %u", EXTRACT_32BITS(tptr) & 0xfffff);
	break;

    case LDP_TLV_STATUS:
	TLV_TCHECK(8);
	ui = EXTRACT_32BITS(tptr);
	tptr+=4;
	printf("\n\t      Status: 0x%02x, Flags: [%s and %s forward]",
	       ui&0x3fffffff,
	       ui&0x80000000 ? "Fatal error" : "Advisory Notification",
	       ui&0x40000000 ? "do" : "don't");
	ui = EXTRACT_32BITS(tptr);
	tptr+=4;
	if (ui)
	    printf(", causing Message ID: 0x%08x", ui);
	break;

    case LDP_TLV_FT_SESSION:
	TLV_TCHECK(8);
	ft_flags = EXTRACT_16BITS(tptr);
	printf("\n\t      Flags: [%sReconnect, %sSave State, %sAll-Label Protection, %s Checkpoint, %sRe-Learn State]",
	       ft_flags&0x8000 ? "" : "No ",
	       ft_flags&0x8 ? "" : "Don't ",
	       ft_flags&0x4 ? "" : "No ",
	       ft_flags&0x2 ? "Sequence Numbered Label" : "All Labels",
	       ft_flags&0x1 ? "" : "Don't ");
	tptr+=4;
	ui = EXTRACT_32BITS(tptr);
	if (ui)
	    printf(", Reconnect Timeout: %ums", ui);
	tptr+=4;
	ui = EXTRACT_32BITS(tptr);
	if (ui)
	    printf(", Recovery Time: %ums", ui);
	break;

    case LDP_TLV_MTU:
	TLV_TCHECK(2);
	printf("\n\t      MTU: %u", EXTRACT_16BITS(tptr));
	break;


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

    case LDP_TLV_HOP_COUNT:
    case LDP_TLV_PATH_VECTOR:
    case LDP_TLV_ATM_LABEL:
    case LDP_TLV_FR_LABEL:
    case LDP_TLV_EXTD_STATUS:
    case LDP_TLV_RETURNED_PDU:
    case LDP_TLV_RETURNED_MSG:
    case LDP_TLV_ATM_SESSION_PARM:
    case LDP_TLV_FR_SESSION_PARM:
    case LDP_TLV_LABEL_REQUEST_MSG_ID:

    default:
        if (vflag <= 1)
            print_unknown_data(tptr,"\n\t      ",tlv_tlen);
        break;
    }
    return(tlv_len+4); /* Type & Length fields not included */
 
trunc:
    printf("\n\t\t packet exceeded snapshot");
    return 0;

badtlv:
    printf("\n\t\t TLV contents go past end of TLV");
    return(tlv_len+4); /* Type & Length fields not included */
}

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

    int processed;
    while (len > (sizeof(struct ldp_common_header) + sizeof(struct ldp_msg_header))) {
        processed = ldp_msg_print(pptr);
        if (processed == 0)
            return;
        len -= processed;
        pptr += processed;
    }
}


int
ldp_msg_print(register const u_char *pptr) {

    const struct ldp_common_header *ldp_com_header;
    const struct ldp_msg_header *ldp_msg_header;
    const u_char *tptr,*msg_tptr;
    u_short tlen;
    u_short pdu_len,msg_len,msg_type,msg_tlen;
    int hexdump,processed;

    tptr=pptr;
    ldp_com_header = (const struct ldp_common_header *)pptr;
    TCHECK(*ldp_com_header);

    /*
     * Sanity checking of the header.
     */
    if (EXTRACT_16BITS(&ldp_com_header->version) != LDP_VERSION) {
	printf("%sLDP version %u packet not supported",
               (vflag < 1) ? "" : "\n\t",
               EXTRACT_16BITS(&ldp_com_header->version));
	return 0;
    }

    /* print the LSR-ID, label-space & length */
    pdu_len = EXTRACT_16BITS(&ldp_com_header->pdu_length);
    printf("%sLDP, Label-Space-ID: %s:%u, pdu-length: %u",
           (vflag < 1) ? "" : "\n\t",
           ipaddr_string(&ldp_com_header->lsr_id),
           EXTRACT_16BITS(&ldp_com_header->label_space),
           pdu_len);

    /* bail out if non-verbose */ 
    if (vflag < 1)
        return 0;

    /* ok they seem to want to know everything - lets fully decode it */
    tlen=pdu_len;

    tptr += sizeof(const struct ldp_common_header);
    tlen -= sizeof(const struct ldp_common_header)-4;	/* Type & Length fields not included */

    while(tlen>0) {
        /* did we capture enough for fully decoding the msg header ? */
        TCHECK2(*tptr, sizeof(struct ldp_msg_header));

        ldp_msg_header = (const struct ldp_msg_header *)tptr;
        msg_len=EXTRACT_16BITS(ldp_msg_header->length);
        msg_type=LDP_MASK_MSG_TYPE(EXTRACT_16BITS(ldp_msg_header->type));

        /* FIXME vendor private / experimental check */
        printf("\n\t  %s Message (0x%04x), length: %u, Message ID: 0x%08x, Flags: [%s if unknown]",
               tok2str(ldp_msg_values,
                       "Unknown",
                       msg_type),
               msg_type,
               msg_len,
               EXTRACT_32BITS(&ldp_msg_header->id),
               LDP_MASK_U_BIT(EXTRACT_16BITS(&ldp_msg_header->type)) ? "continue processing" : "ignore");

        if (msg_len == 0) /* infinite loop protection */
            return 0;

        msg_tptr=tptr+sizeof(struct ldp_msg_header);
        msg_tlen=msg_len-sizeof(struct ldp_msg_header)+4; /* Type & Length fields not included */

        /* did we capture enough for fully decoding the message ? */
        TCHECK2(*tptr, msg_len);
        hexdump=FALSE;

        switch(msg_type) {
 
        case LDP_MSG_NOTIF:
        case LDP_MSG_HELLO:
        case LDP_MSG_INIT:
        case LDP_MSG_KEEPALIVE:
        case LDP_MSG_ADDRESS:
        case LDP_MSG_LABEL_MAPPING:
        case LDP_MSG_ADDRESS_WITHDRAW:
        case LDP_MSG_LABEL_WITHDRAW:
            while(msg_tlen >= 4) {
                processed = ldp_tlv_print(msg_tptr);
                if (processed == 0)
                    break;
                msg_tlen-=processed;
                msg_tptr+=processed;
            }
            break;

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

        case LDP_MSG_LABEL_REQUEST:
        case LDP_MSG_LABEL_RELEASE:
        case LDP_MSG_LABEL_ABORT_REQUEST:

        default:
            if (vflag <= 1)
                print_unknown_data(msg_tptr,"\n\t  ",msg_tlen);
            break;
        }
        /* do we want to see an additionally hexdump ? */
        if (vflag > 1 || hexdump==TRUE)
            print_unknown_data(tptr+sizeof(struct ldp_msg_header),"\n\t  ",
                               msg_len);

        tptr += msg_len+4;
        tlen -= msg_len+4;
    }
    return pdu_len+4;
trunc:
    printf("\n\t\t packet exceeded snapshot");
    return 0;
}