#ifndef lint
static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.43 1999-10-07 23:47:11 mcr Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.51 2001-09-17 21:57:54 fenner Exp $ (LBL)";
+#endif
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
#endif
#include <sys/param.h>
#include <sys/time.h>
-#include <sys/socket.h>
-
-#if __STDC__
-struct mbuf;
-struct rtentry;
-#endif
-#include <net/if.h>
#include <netinet/in.h>
-#include <netinet/if_ether.h>
-#ifdef HAVE_MEMORY_H
-#include <memory.h>
-#endif
#include <stdio.h>
#include <string.h>
#include "interface.h"
#include "addrtoname.h"
+#include "ether.h"
#include "ethertype.h"
#include "extract.h" /* must come after interface.h */
-/* Compatibility */
-#ifndef REVARP_REQUEST
-#define REVARP_REQUEST 3
-#endif
-#ifndef REVARP_REPLY
-#define REVARP_REPLY 4
+/*
+ * Address Resolution Protocol.
+ *
+ * See RFC 826 for protocol description. ARP packets are variable
+ * in size; the arphdr structure defines the fixed-length portion.
+ * Protocol type values are the same as those for 10 Mb/s Ethernet.
+ * It is followed by the variable-sized fields ar_sha, arp_spa,
+ * arp_tha and arp_tpa in that order, according to the lengths
+ * specified. Field names used correspond to RFC 826.
+ */
+struct arphdr {
+ u_short ar_hrd; /* format of hardware address */
+#define ARPHRD_ETHER 1 /* ethernet hardware format */
+#define ARPHRD_IEEE802 6 /* token-ring hardware format */
+#define ARPHRD_ARCNET 7 /* arcnet hardware format */
+#define ARPHRD_FRELAY 15 /* frame relay hardware format */
+#define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */
+#define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */
+ u_short ar_pro; /* format of protocol address */
+ u_char ar_hln; /* length of hardware address */
+ u_char ar_pln; /* length of protocol address */
+ u_short ar_op; /* one of: */
+#define ARPOP_REQUEST 1 /* request to resolve address */
+#define ARPOP_REPLY 2 /* response to previous request */
+#define ARPOP_REVREQUEST 3 /* request protocol address given hardware */
+#define ARPOP_REVREPLY 4 /* response giving protocol address */
+#define ARPOP_INVREQUEST 8 /* request to identify peer */
+#define ARPOP_INVREPLY 9 /* response identifying peer */
+/*
+ * The remaining fields are variable in size,
+ * according to the sizes above.
+ */
+#ifdef COMMENT_ONLY
+ u_char ar_sha[]; /* sender hardware address */
+ u_char ar_spa[]; /* sender protocol address */
+ u_char ar_tha[]; /* target hardware address */
+ u_char ar_tpa[]; /* target protocol address */
#endif
+#define ar_sha(ap) (((const caddr_t)((ap)+1))+0)
+#define ar_spa(ap) (((const caddr_t)((ap)+1))+ (ap)->ar_hln)
+#define ar_tha(ap) (((const caddr_t)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln)
+#define ar_tpa(ap) (((const caddr_t)((ap)+1))+2*(ap)->ar_hln+(ap)->ar_pln)
+};
+
+#define ARP_HDRLEN 8
+
+#define HRD(ap) ((ap)->ar_hrd)
+#define HLN(ap) ((ap)->ar_hln)
+#define PLN(ap) ((ap)->ar_pln)
+#define OP(ap) ((ap)->ar_op)
+#define PRO(ap) ((ap)->ar_pro)
+#define SHA(ap) (ar_sha(ap))
+#define SPA(ap) (ar_spa(ap))
+#define THA(ap) (ar_tha(ap))
+#define TPA(ap) (ar_tpa(ap))
static u_char ezero[6];
void
-arp_print(register const u_char *bp, u_int length, u_int caplen)
+arp_print(const u_char *bp, u_int length, u_int caplen)
{
- register const struct ether_arp *ap;
- register const struct ether_header *eh;
- register u_short pro, hrd, op;
+ const struct arphdr *ap;
+ u_short pro, hrd, op;
- ap = (struct ether_arp *)bp;
- if ((u_char *)(ap + 1) > snapend) {
- printf("[|arp]");
- return;
- }
- if (length < sizeof(struct ether_arp)) {
+ ap = (const struct arphdr *)bp;
+ TCHECK(*ap);
+ if ((const u_char *)(ar_tpa(ap) + PLN(ap)) > snapend) {
(void)printf("truncated-arp");
- default_print((u_char *)ap, length);
+ default_print((const u_char *)ap, length);
return;
}
- pro = EXTRACT_16BITS(&ap->arp_pro);
- hrd = EXTRACT_16BITS(&ap->arp_hrd);
- op = EXTRACT_16BITS(&ap->arp_op);
+ pro = EXTRACT_16BITS(&PRO(ap));
+ hrd = EXTRACT_16BITS(&HRD(ap));
+ op = EXTRACT_16BITS(&OP(ap));
- if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
- || ap->arp_hln != sizeof(SHA(ap))
- || ap->arp_pln != sizeof(SPA(ap))) {
+ if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) {
(void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)",
- op, pro, ap->arp_pln,
- hrd, ap->arp_hln);
+ op, pro, PLN(ap), hrd, HLN(ap));
return;
}
if (pro == ETHERTYPE_TRAIL)
(void)printf("trailer-");
- eh = (struct ether_header *)packetp;
switch (op) {
case ARPOP_REQUEST:
(void)printf("arp who-has %s", ipaddr_string(TPA(ap)));
- if (memcmp((char *)ezero, (char *)THA(ap), 6) != 0)
- (void)printf(" (%s)", etheraddr_string(THA(ap)));
+ if (memcmp((const char *)ezero, (const char *)THA(ap), HLN(ap)) != 0)
+ (void)printf(" (%s)",
+ linkaddr_string(THA(ap), HLN(ap)));
(void)printf(" tell %s", ipaddr_string(SPA(ap)));
- if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
- (void)printf(" (%s)", etheraddr_string(SHA(ap)));
break;
case ARPOP_REPLY:
(void)printf("arp reply %s", ipaddr_string(SPA(ap)));
- if (memcmp((char *)ESRC(eh), (char *)SHA(ap), 6) != 0)
- (void)printf(" (%s)", etheraddr_string(SHA(ap)));
- (void)printf(" is-at %s", etheraddr_string(SHA(ap)));
- if (memcmp((char *)EDST(eh), (char *)THA(ap), 6) != 0)
- (void)printf(" (%s)", etheraddr_string(THA(ap)));
+ (void)printf(" is-at %s", linkaddr_string(SHA(ap), HLN(ap)));
break;
- case REVARP_REQUEST:
+ case ARPOP_REVREQUEST:
(void)printf("rarp who-is %s tell %s",
- etheraddr_string(THA(ap)),
- etheraddr_string(SHA(ap)));
+ linkaddr_string(THA(ap), HLN(ap)),
+ linkaddr_string(SHA(ap), HLN(ap)));
break;
- case REVARP_REPLY:
+ case ARPOP_REVREPLY:
(void)printf("rarp reply %s at %s",
- etheraddr_string(THA(ap)),
+ linkaddr_string(THA(ap), HLN(ap)),
ipaddr_string(TPA(ap)));
break;
default:
(void)printf("arp-#%d", op);
- default_print((u_char *)ap, caplen);
+ default_print((const u_char *)ap, caplen);
return;
}
if (hrd != ARPHRD_ETHER)
printf(" hardware #%d", hrd);
+ return;
+trunc:
+ (void)printf("[|arp]");
}
projects / tcpdump / blobdiff