X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/b9ac23ce92ca22483d56ee3192c54aa8f782f9ac..f01a14ae44e67d54f6bb89f034ed1b39a5c3f565:/print-arp.c diff --git a/print-arp.c b/print-arp.c index 4760f817..cbeb47af 100644 --- a/print-arp.c +++ b/print-arp.c @@ -21,7 +21,7 @@ #ifndef lint static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.44 1999-11-21 09:36:48 fenner Exp $ (LBL)"; + "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.50 2001-06-18 09:12:28 itojun Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H @@ -30,100 +30,128 @@ static const char rcsid[] = #include #include -#include - -#if __STDC__ -struct mbuf; -struct rtentry; -#endif -#include #include -#include -#ifdef HAVE_MEMORY_H -#include -#endif #include #include #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) (((caddr_t)((ap)+1))+0) +#define ar_spa(ap) (((caddr_t)((ap)+1))+ (ap)->ar_hln) +#define ar_tha(ap) (((caddr_t)((ap)+1))+ (ap)->ar_hln+(ap)->ar_pln) +#define ar_tpa(ap) (((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) { + ap = (struct arphdr *)bp; + if ((u_char *)(ap + 1) > snapend) { printf("[|arp]"); return; } - if (length < sizeof(struct ether_arp)) { + if ((u_char *)(ar_tpa(ap) + PLN(ap)) > snapend) { (void)printf("truncated-arp"); default_print((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((char *)ezero, (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;