168 lines
5.4 KiB
C
168 lines
5.4 KiB
C
/*
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* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $FreeBSD$
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*/
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#ifndef lint
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static const char rcsid[] =
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"@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.51 2001/09/17 21:57:54 fenner Exp $ (LBL)";
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#endif
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <sys/param.h>
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#include <sys/time.h>
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#include <netinet/in.h>
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#include <stdio.h>
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#include <string.h>
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#include "interface.h"
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#include "addrtoname.h"
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#include "ether.h"
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#include "ethertype.h"
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#include "extract.h" /* must come after interface.h */
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/*
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* Address Resolution Protocol.
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*
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* See RFC 826 for protocol description. ARP packets are variable
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* in size; the arphdr structure defines the fixed-length portion.
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* Protocol type values are the same as those for 10 Mb/s Ethernet.
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* It is followed by the variable-sized fields ar_sha, arp_spa,
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* arp_tha and arp_tpa in that order, according to the lengths
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* specified. Field names used correspond to RFC 826.
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*/
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struct arphdr {
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u_short ar_hrd; /* format of hardware address */
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#define ARPHRD_ETHER 1 /* ethernet hardware format */
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#define ARPHRD_IEEE802 6 /* token-ring hardware format */
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#define ARPHRD_ARCNET 7 /* arcnet hardware format */
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#define ARPHRD_FRELAY 15 /* frame relay hardware format */
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#define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */
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#define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */
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u_short ar_pro; /* format of protocol address */
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u_char ar_hln; /* length of hardware address */
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u_char ar_pln; /* length of protocol address */
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u_short ar_op; /* one of: */
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#define ARPOP_REQUEST 1 /* request to resolve address */
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#define ARPOP_REPLY 2 /* response to previous request */
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#define ARPOP_REVREQUEST 3 /* request protocol address given hardware */
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#define ARPOP_REVREPLY 4 /* response giving protocol address */
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#define ARPOP_INVREQUEST 8 /* request to identify peer */
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#define ARPOP_INVREPLY 9 /* response identifying peer */
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/*
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* The remaining fields are variable in size,
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* according to the sizes above.
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*/
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#ifdef COMMENT_ONLY
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u_char ar_sha[]; /* sender hardware address */
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u_char ar_spa[]; /* sender protocol address */
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u_char ar_tha[]; /* target hardware address */
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u_char ar_tpa[]; /* target protocol address */
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#endif
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#define ar_sha(ap) (((const caddr_t)((ap)+1))+0)
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#define ar_spa(ap) (((const caddr_t)((ap)+1))+ (ap)->ar_hln)
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#define ar_tha(ap) (((const caddr_t)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln)
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#define ar_tpa(ap) (((const caddr_t)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
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};
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#define ARP_HDRLEN 8
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#define HRD(ap) ((ap)->ar_hrd)
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#define HLN(ap) ((ap)->ar_hln)
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#define PLN(ap) ((ap)->ar_pln)
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#define OP(ap) ((ap)->ar_op)
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#define PRO(ap) ((ap)->ar_pro)
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#define SHA(ap) (ar_sha(ap))
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#define SPA(ap) (ar_spa(ap))
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#define THA(ap) (ar_tha(ap))
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#define TPA(ap) (ar_tpa(ap))
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static u_char ezero[6];
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void
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arp_print(const u_char *bp, u_int length, u_int caplen)
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{
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const struct arphdr *ap;
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u_short pro, hrd, op;
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ap = (const struct arphdr *)bp;
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TCHECK(*ap);
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if ((const u_char *)(ar_tpa(ap) + PLN(ap)) > snapend) {
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(void)printf("truncated-arp");
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default_print((const u_char *)ap, length);
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return;
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}
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pro = EXTRACT_16BITS(&PRO(ap));
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hrd = EXTRACT_16BITS(&HRD(ap));
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op = EXTRACT_16BITS(&OP(ap));
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if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) {
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(void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
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op, pro, PLN(ap), hrd, HLN(ap));
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return;
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}
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if (pro == ETHERTYPE_TRAIL)
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(void)printf("trailer-");
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switch (op) {
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case ARPOP_REQUEST:
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(void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
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if (memcmp((const char *)ezero, (const char *)THA(ap), HLN(ap)) != 0)
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(void)printf(" (%s)",
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linkaddr_string(THA(ap), HLN(ap)));
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(void)printf(" tell %s", ipaddr_string(SPA(ap)));
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break;
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case ARPOP_REPLY:
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(void)printf("arp reply %s", ipaddr_string(SPA(ap)));
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(void)printf(" is-at %s", linkaddr_string(SHA(ap), HLN(ap)));
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break;
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case ARPOP_REVREQUEST:
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(void)printf("rarp who-is %s tell %s",
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linkaddr_string(THA(ap), HLN(ap)),
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linkaddr_string(SHA(ap), HLN(ap)));
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break;
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case ARPOP_REVREPLY:
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(void)printf("rarp reply %s at %s",
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linkaddr_string(THA(ap), HLN(ap)),
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ipaddr_string(TPA(ap)));
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break;
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default:
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(void)printf("arp-#%d", op);
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default_print((const u_char *)ap, caplen);
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return;
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}
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if (hrd != ARPHRD_ETHER)
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printf(" hardware #%d", hrd);
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return;
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trunc:
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(void)printf("[|arp]");
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}
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