print-arp.c revision 26183 
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 const char rcsid[] =
24    "@(#) $Header: print-arp.c,v 1.41 96/10/27 14:54:50 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#include <stdio.h>
42#include <string.h>
43
44#include "interface.h"
45#include "addrtoname.h"
46#include "ethertype.h"
47#include "extract.h"			/* must come after interface.h */
48
49/* Compatibility */
50#ifndef REVARP_REQUEST
51#define REVARP_REQUEST		3
52#endif
53#ifndef REVARP_REPLY
54#define REVARP_REPLY		4
55#endif
56
57static u_char ezero[6];
58
59void
60arp_print(register const u_char *bp, u_int length, u_int caplen)
61{
62	register const struct ether_arp *ap;
63	register const struct ether_header *eh;
64	register u_short pro, hrd, op;
65
66	ap = (struct ether_arp *)bp;
67	if ((u_char *)(ap + 1) > snapend) {
68		printf("[|arp]");
69		return;
70	}
71	if (length < sizeof(struct ether_arp)) {
72		(void)printf("truncated-arp");
73		default_print((u_char *)ap, length);
74		return;
75	}
76
77	pro = EXTRACT_16BITS(&ap->arp_pro);
78	hrd = EXTRACT_16BITS(&ap->arp_hrd);
79	op = EXTRACT_16BITS(&ap->arp_op);
80
81	if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
82	    || ap->arp_hln != sizeof(SHA(ap))
83	    || ap->arp_pln != sizeof(SPA(ap))) {
84		(void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
85				op, pro, ap->arp_pln,
86				hrd, ap->arp_hln);
87		return;
88	}
89	if (pro == ETHERTYPE_TRAIL)
90		(void)printf("trailer-");
91	eh = (struct ether_header *)packetp;
92	switch (op) {
93
94	case ARPOP_REQUEST:
95		(void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
96		if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0)
97			(void)printf(" (%s)", etheraddr_string(THA(ap)));
98		(void)printf(" tell %s", ipaddr_string(SPA(ap)));
99		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
100			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
101		break;
102
103	case ARPOP_REPLY:
104		(void)printf("arp reply %s", ipaddr_string(SPA(ap)));
105		if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
106			(void)printf(" (%s)", etheraddr_string(SHA(ap)));
107		(void)printf(" is-at %s", etheraddr_string(SHA(ap)));
108		if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0)
109			(void)printf(" (%s)", etheraddr_string(THA(ap)));
110		break;
111
112	case REVARP_REQUEST:
113		(void)printf("rarp who-is %s tell %s",
114			etheraddr_string(THA(ap)),
115			etheraddr_string(SHA(ap)));
116		break;
117
118	case REVARP_REPLY:
119		(void)printf("rarp reply %s at %s",
120			etheraddr_string(THA(ap)),
121			ipaddr_string(TPA(ap)));
122		break;
123
124	default:
125		(void)printf("arp-#%d", op);
126		default_print((u_char *)ap, caplen);
127		return;
128	}
129	if (hrd != ARPHRD_ETHER)
130		printf(" hardware #%d", hrd);
131}
132