print-arp.c revision 39300 
1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 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
22#ifndef lint
23static const char rcsid[] =
24    "@(#) $Header: print-arp.c,v 1.43 97/06/15 13:20:27 leres Exp $ (LBL)";
25#endif
26
27#include <sys/param.h>
28#include <sys/time.h>
29#include <sys/socket.h>
30
31#if __STDC__
32struct mbuf;
33struct rtentry;
34#endif
35#include <net/if.h>
36#include <net/if_var.h>
37
38#include <netinet/in.h>
39#include <netinet/if_ether.h>
40
41#ifdef HAVE_MEMORY_H
42#include <memory.h>
43#endif
44#include <stdio.h>
45#include <string.h>
46
47#include "interface.h"
48#include "addrtoname.h"
49#include "ethertype.h"
50#include "extract.h"			/* must come after interface.h */
51
52/* Compatibility */
53#ifndef REVARP_REQUEST
54#define REVARP_REQUEST		3
55#endif
56#ifndef REVARP_REPLY
57#define REVARP_REPLY		4
58#endif
59
60static u_char ezero[6];
61
62void
63arp_print(register const u_char *bp, u_int length, u_int caplen)
64{
65	register const struct ether_arp *ap;
66	register const struct ether_header *eh;
67	register u_short pro, hrd, op;
68
69	ap = (struct ether_arp *)bp;
70	if ((u_char *)(ap + 1) > snapend) {
71		printf("[|arp]");
72		return;
73	}
74	if (length < sizeof(struct ether_arp)) {
75		(void)printf("truncated-arp");
76		default_print((u_char *)ap, length);
77		return;
78	}
79
80	pro = EXTRACT_16BITS(&ap->arp_pro);
81	hrd = EXTRACT_16BITS(&ap->arp_hrd);
82	op = EXTRACT_16BITS(&ap->arp_op);
83
84	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
85	    || ap->arp_hln != sizeof(SHA(ap))
86	    || ap->arp_pln != sizeof(SPA(ap))) {
87		(void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
88				op, pro, ap->arp_pln,
89				hrd, ap->arp_hln);
90		return;
91	}
92	if (pro == ETHERTYPE_TRAIL)
93		(void)printf("trailer-");
94	eh = (struct ether_header *)packetp;
95	switch (op) {
96
97	case ARPOP_REQUEST:
98		(void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
99		if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0)
100			(void)printf(" (%s)", etheraddr_string(THA(ap)));
101		(void)printf(" tell %s", ipaddr_string(SPA(ap)));
102		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
103			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
104		break;
105
106	case ARPOP_REPLY:
107		(void)printf("arp reply %s", ipaddr_string(SPA(ap)));
108		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
109			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
110		(void)printf(" is-at %s", etheraddr_string(SHA(ap)));
111		if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0)
112			(void)printf(" (%s)", etheraddr_string(THA(ap)));
113		break;
114
115	case REVARP_REQUEST:
116		(void)printf("rarp who-is %s tell %s",
117			etheraddr_string(THA(ap)),
118			etheraddr_string(SHA(ap)));
119		break;
120
121	case REVARP_REPLY:
122		(void)printf("rarp reply %s at %s",
123			etheraddr_string(THA(ap)),
124			ipaddr_string(TPA(ap)));
125		break;
126
127	default:
128		(void)printf("arp-#%d", op);
129		default_print((u_char *)ap, caplen);
130		return;
131	}
132	if (hrd != ARPHRD_ETHER)
133		printf(" hardware #%d", hrd);
134}
135