print-cdp.c

/*
 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
 *	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.
 *
 * Code by Gert Doering, SpaceNet GmbH, gert@space.net
 *
 * Reference documentation:
 *    http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.4 2000-07-29 07:27:54 assar Exp $";
#endif

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

#include <sys/param.h>
#include <sys/time.h>

#include <netinet/in.h>

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

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

static void cdp_print_addr( const u_char * p, int l );
static void cdp_print_prefixes( const u_char * p, int l );

/*
 * Returns non-zero IFF it succeeds in printing the header
 */
void
cdp_print(const u_char *p, u_int length, u_int caplen,
	  const u_char *esrc, const u_char *edst)
{
	int i;
	int type, len;

	/* Cisco Discovery Protocol */


	if ( caplen < 12 ) {
		(void)printf("[|cdp]");
		return;
	}

	i=8;		/* CDP data starts at offset 8 */
	printf ("CDP v%d, ttl=%ds", p[i], p[i+1] );
	i+=4;		/* skip version, TTL and chksum */

	while (i < length) {
	    if ( i+4 > caplen ) {
		printf("[!cdp]");
		return;
	    }
	    type = (p[i]<<8) + p[i+1];
	    len  = (p[i+2]<<8) + p[i+3];

	    if ( vflag )
		printf( "\n\t%02x/%02x", type, len );
	    else
		printf( "\n\t" );

	    if ( i+len > caplen ) {
		printf("[!cdp]");
		return;
	    }

	    switch( type )
	    {
	    case 0x01:
		printf( " DevID '%.*s'", len-4, p+i+4 );
		break;
	    case 0x02:
		printf( " Addr" );
		cdp_print_addr( p+i+4, len-4 );
		break;
	    case 0x03:
		printf( " PortID '%.*s'", len-4, p+i+4 );
		break;
	    case 0x04:
		printf( " CAP 0x%02x", (unsigned) p[i+7] );
		break;
	    case 0x05:
		if ( vflag )
		    printf( " Version:\n%.*s", len-4, p+i+4 );
		else
		    printf( " Version: (suppressed)" );
		break;
	    case 0x06:
		printf( " Platform: '%.*s'", len-4, p+i+4 );
		break;
	    case 0x07:
	        cdp_print_prefixes( p+i+4, len-4 );
		break;
	    case 0x09:		/* guess - not documented */
		printf( " VTP Management Domain: '%.*s'", len-4, p+i+4 );
		break;
	    case 0x0a:		/* guess - not documented */
		printf( " Native VLAN ID: %d", (p[i+4]<<8) + p[i+4+1] - 1 );
		break;
	    case 0x0b:		/* guess - not documented */
		printf( " Duplex: %s", p[i+4] ? "full": "half" );
		break;
	    default:
		printf( " unknown field type %02x, len %d", type, len );
	    }

	    /* avoid infinite loop */
	    if (len == 0)
		break;
	    i+=len;
	}
}

static void
cdp_print_addr( const u_char * p, int l )
{
	int pl, al, num;
	const u_char * endp = p+l;

	num = (p[0] << 24) + (p[1]<<16) + (p[2]<<8)+ p[3];
	p+=4;

	printf(" (%d): ", num );

	while( p < endp && num >= 0) {
		pl=*(p+1);
		p+=2; 

		/* special case: IPv4, protocol type=0xcc, addr. length=4 */
		if ( pl == 1 && *p == 0xcc && 
		     p[1] == 0 && p[2] == 4 ) {
			p+=3;

			printf( "IPv4 %d.%d.%d.%d ", p[0], p[1], p[2], p[3] );
			p+=4;
		} else {	/* generic case: just print raw data */
			printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl);
			while( pl-- > 0 )
				printf( " %02x", *p++);
			al=(*p << 8) + *(p+1);
			printf( ", al=%d, a=", al );
			p+=2; 
			while( al-- > 0 )
				printf( " %02x", *p++);
		}
		printf("  ");
		num--;
	}
}


static void
cdp_print_prefixes( const u_char * p, int l )
{
    printf( " IPv4 Prefixes (%d):", l/5 );

    while(l > 0) {
	printf( " %d.%d.%d.%d/%d", p[0], p[1], p[2], p[3], p[4] );
	l-=5; p+=5;
    }
}