xref: /openbsd-src/usr.sbin/tcpdump/print-cdp.c (revision 98dbb244f271769c9a461b8976ee0261b82263f2)

/*	$OpenBSD: print-cdp.c,v 1.8 2019/09/11 15:20:30 martijn Exp $	*/

/*
 * 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
 */

#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 */

int cdp_print_addr(const u_char * p, int l);
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, int i)
{
	int type, len;

	/* Cisco Discovery Protocol */

	if (caplen < i + 4) {
		printf("[|cdp]");
		return;
	}

	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(" %02x/%02x", type, len);

		if (len < 4)
			goto error;

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

		/* http://www.cisco.com/c/en/us/support/docs/switches/catalyst-4500-series-switches/13414-103.html#cdp */
		switch(type) {
		case 0x01:
			printf(" DevID '%.*s'", len - 4, p + i + 4);
			break;
		case 0x02:
			printf(" Addr");
			if (cdp_print_addr(p + i + 4, len - 4))
				goto error;
			break;
		case 0x03:
			printf(" PortID '%.*s'", len - 4, p + i + 4);
			break;
		case 0x04:
			if (len < 8)
				goto error;
			printf(" CAP 0x%02x", (unsigned) p[i+7]);
			break;
		case 0x05:
			if (vflag)
				printf(" Version %.*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:
			printf(" VTP-Management-Domain '%.*s'", len-4, p+i+4 );
			break;
		case 0x0a:
			if (len < 6)
				goto error;
			printf(" Native-VLAN-ID %d", (p[i+4]<<8) + p[i+4+1]);
			break;
		case 0x0b:
			if (len < 5)
				goto error;
			printf(" Duplex %s", p[i+4] ? "full": "half" );
			break;
		default:
			printf(" unknown-type %02x len %d", type, len );
		}

		/* avoid infinite loop */
		if (len == 0)
			break;
		i += len;
	}
error:
	printf("[!cdp]");
}

#define CDP_CHECK_ACCESS(p, s) if ((endp - (p)) < (s)) return 1

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

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

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

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

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

			CDP_CHECK_ACCESS(p, 4);
			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=", pt, pl);

			CDP_CHECK_ACCESS(p, pl);
			while(pl-- > 0)
				printf(" %02x", *p++);

			CDP_CHECK_ACCESS(p, 2);
			al=(*p << 8) + *(p+1);
			printf(", al=%d, a=", al);
			p+=2;

			CDP_CHECK_ACCESS(p, al);
			while(al-- > 0)
				printf(" %02x", *p++);
		}
		printf("  ");
		num--;
	}

	return 0;
}


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

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