print-arp.c revision 17681 
1/*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996
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 char rcsid[] =
24    "@(#) $Header: print-arp.c,v 1.39 96/07/17 14:56:17 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
37#include <netinet/in.h>
38#include <netinet/if_ether.h>
39
40#include <stdio.h>
41#include <string.h>
42
43#include "interface.h"
44#include "addrtoname.h"
45#include "ethertype.h"
46#include "extract.h"			/* must come after interface.h */
47
48/* Compatibility */
49#ifndef REVARP_REQUEST
50#define REVARP_REQUEST		3
51#endif
52#ifndef REVARP_REPLY
53#define REVARP_REPLY		4
54#endif
55
56static u_char ezero[6];
57
58void
59arp_print(register const u_char *bp, u_int length, u_int caplen)
60{
61	register const struct ether_arp *ap;
62	register const struct ether_header *eh;
63	register u_short pro, hrd, op;
64
65	ap = (struct ether_arp *)bp;
66	if ((u_char *)(ap + 1) > snapend) {
67		printf("[|arp]");
68		return;
69	}
70	if (length < sizeof(struct ether_arp)) {
71		(void)printf("truncated-arp");
72		default_print((u_char *)ap, length);
73		return;
74	}
75
76	pro = EXTRACT_16BITS(&ap->arp_pro);
77	hrd = EXTRACT_16BITS(&ap->arp_hrd);
78	op = EXTRACT_16BITS(&ap->arp_op);
79
80	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
81	    || ap->arp_hln != sizeof(SHA(ap))
82	    || ap->arp_pln != sizeof(SPA(ap))) {
83		(void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
84				op, pro, ap->arp_pln,
85				hrd, ap->arp_hln);
86		return;
87	}
88	if (pro == ETHERTYPE_TRAIL)
89		(void)printf("trailer-");
90	eh = (struct ether_header *)packetp;
91	switch (op) {
92
93	case ARPOP_REQUEST:
94		(void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
95		if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0)
96			(void)printf(" (%s)", etheraddr_string(THA(ap)));
97		(void)printf(" tell %s", ipaddr_string(SPA(ap)));
98		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
99			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
100		break;
101
102	case ARPOP_REPLY:
103		(void)printf("arp reply %s", ipaddr_string(SPA(ap)));
104		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
105			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
106		(void)printf(" is-at %s", etheraddr_string(SHA(ap)));
107		if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0)
108			(void)printf(" (%s)", etheraddr_string(THA(ap)));
109		break;
110
111	case REVARP_REQUEST:
112		(void)printf("rarp who-is %s tell %s",
113			etheraddr_string(THA(ap)),
114			etheraddr_string(SHA(ap)));
115		break;
116
117	case REVARP_REPLY:
118		(void)printf("rarp reply %s at %s",
119			etheraddr_string(THA(ap)),
120			ipaddr_string(TPA(ap)));
121		break;
122
123	default:
124		(void)printf("arp-#%d", op);
125		default_print((u_char *)ap, caplen);
126		return;
127	}
128	if (hrd != ARPHRD_ETHER)
129		printf(" hardware #%d", ap->arp_hrd);
130}
131