print-cdp.c revision 75115 
1/*
2 * Copyright (c) 1992, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * Code by Gert Doering, SpaceNet GmbH, gert@space.net
22 *
23 * Reference documentation:
24 *    http://www.cisco.com/univercd/cc/td/doc/product/lan/trsrb/frames.htm
25 */
26
27#ifndef lint
28static const char rcsid[] =
29    "@(#) $Header: /tcpdump/master/tcpdump/print-cdp.c,v 1.4 2000/07/29 07:27:54 assar Exp $";
30#endif
31
32#ifdef HAVE_CONFIG_H
33#include "config.h"
34#endif
35
36#include <sys/param.h>
37#include <sys/time.h>
38
39#include <netinet/in.h>
40
41#include <ctype.h>
42#include <netdb.h>
43#include <stdio.h>
44#include <string.h>
45
46#include "interface.h"
47#include "addrtoname.h"
48#include "extract.h"			/* must come after interface.h */
49
50static void cdp_print_addr( const u_char * p, int l );
51static void cdp_print_prefixes( const u_char * p, int l );
52
53/*
54 * Returns non-zero IFF it succeeds in printing the header
55 */
56void
57cdp_print(const u_char *p, u_int length, u_int caplen,
58	  const u_char *esrc, const u_char *edst)
59{
60	int i;
61	int type, len;
62
63	/* Cisco Discovery Protocol */
64
65
66	if ( caplen < 12 ) {
67		(void)printf("[|cdp]");
68		return;
69	}
70
71	i=8;		/* CDP data starts at offset 8 */
72	printf ("CDP v%d, ttl=%ds", p[i], p[i+1] );
73	i+=4;		/* skip version, TTL and chksum */
74
75	while (i < length) {
76	    if ( i+4 > caplen ) {
77		printf("[!cdp]");
78		return;
79	    }
80	    type = (p[i]<<8) + p[i+1];
81	    len  = (p[i+2]<<8) + p[i+3];
82
83	    if ( vflag )
84		printf( "\n\t%02x/%02x", type, len );
85	    else
86		printf( "\n\t" );
87
88	    if ( i+len > caplen ) {
89		printf("[!cdp]");
90		return;
91	    }
92
93	    switch( type )
94	    {
95	    case 0x01:
96		printf( " DevID '%.*s'", len-4, p+i+4 );
97		break;
98	    case 0x02:
99		printf( " Addr" );
100		cdp_print_addr( p+i+4, len-4 );
101		break;
102	    case 0x03:
103		printf( " PortID '%.*s'", len-4, p+i+4 );
104		break;
105	    case 0x04:
106		printf( " CAP 0x%02x", (unsigned) p[i+7] );
107		break;
108	    case 0x05:
109		if ( vflag )
110		    printf( " Version:\n%.*s", len-4, p+i+4 );
111		else
112		    printf( " Version: (suppressed)" );
113		break;
114	    case 0x06:
115		printf( " Platform: '%.*s'", len-4, p+i+4 );
116		break;
117	    case 0x07:
118	        cdp_print_prefixes( p+i+4, len-4 );
119		break;
120	    case 0x09:		/* guess - not documented */
121		printf( " VTP Management Domain: '%.*s'", len-4, p+i+4 );
122		break;
123	    case 0x0a:		/* guess - not documented */
124		printf( " Native VLAN ID: %d", (p[i+4]<<8) + p[i+4+1] - 1 );
125		break;
126	    case 0x0b:		/* guess - not documented */
127		printf( " Duplex: %s", p[i+4] ? "full": "half" );
128		break;
129	    default:
130		printf( " unknown field type %02x, len %d", type, len );
131	    }
132
133	    /* avoid infinite loop */
134	    if (len == 0)
135		break;
136	    i+=len;
137	}
138}
139
140static void
141cdp_print_addr( const u_char * p, int l )
142{
143	int pl, al, num;
144	const u_char * endp = p+l;
145
146	num = (p[0] << 24) + (p[1]<<16) + (p[2]<<8)+ p[3];
147	p+=4;
148
149	printf(" (%d): ", num );
150
151	while( p < endp && num >= 0) {
152		pl=*(p+1);
153		p+=2;
154
155		/* special case: IPv4, protocol type=0xcc, addr. length=4 */
156		if ( pl == 1 && *p == 0xcc &&
157		     p[1] == 0 && p[2] == 4 ) {
158			p+=3;
159
160			printf( "IPv4 %d.%d.%d.%d ", p[0], p[1], p[2], p[3] );
161			p+=4;
162		} else {	/* generic case: just print raw data */
163			printf("pt=0x%02x, pl=%d, pb=", *(p-2), pl);
164			while( pl-- > 0 )
165				printf( " %02x", *p++);
166			al=(*p << 8) + *(p+1);
167			printf( ", al=%d, a=", al );
168			p+=2;
169			while( al-- > 0 )
170				printf( " %02x", *p++);
171		}
172		printf("  ");
173		num--;
174	}
175}
176
177
178static void
179cdp_print_prefixes( const u_char * p, int l )
180{
181    printf( " IPv4 Prefixes (%d):", l/5 );
182
183    while(l > 0) {
184	printf( " %d.%d.%d.%d/%d", p[0], p[1], p[2], p[3], p[4] );
185	l-=5; p+=5;
186    }
187}
188