| /* |
| * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 |
| * The Regents of the University of California. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that: (1) source code distributions |
| * retain the above copyright notice and this paragraph in its entirety, (2) |
| * distributions including binary code include the above copyright notice and |
| * this paragraph in its entirety in the documentation or other materials |
| * provided with the distribution, and (3) all advertising materials mentioning |
| * features or use of this software display the following acknowledgement: |
| * ``This product includes software developed by the University of California, |
| * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of |
| * the University nor the names of its contributors may be used to endorse |
| * or promote products derived from this software without specific prior |
| * written permission. |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| */ |
| |
| #ifndef lint |
| static const char rcsid[] = |
| "@(#) $Header: /tcpdump/master/tcpdump/print-arp.c,v 1.49 2000-10-10 05:05:07 guy Exp $ (LBL)"; |
| #endif |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include <sys/param.h> |
| #include <sys/time.h> |
| |
| #include <netinet/in.h> |
| |
| #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 */ |
| |
| /* |
| * 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_FRELAY 15 /* frame relay 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 ARP_HDRLEN 8 |
| |
| /* |
| * Ethernet Address Resolution Protocol. |
| * |
| * See RFC 826 for protocol description. Structure below is adapted |
| * to resolving internet addresses. Field names used correspond to |
| * RFC 826. |
| */ |
| struct ether_arp { |
| struct arphdr ea_hdr; /* fixed-size header */ |
| u_char arp_sha[6]; /* sender hardware address */ |
| u_char arp_spa[4]; /* sender protocol address */ |
| u_char arp_tha[6]; /* target hardware address */ |
| u_char arp_tpa[4]; /* target protocol address */ |
| }; |
| #define arp_hrd ea_hdr.ar_hrd |
| #define arp_pro ea_hdr.ar_pro |
| #define arp_hln ea_hdr.ar_hln |
| #define arp_pln ea_hdr.ar_pln |
| #define arp_op ea_hdr.ar_op |
| |
| #define ETHER_ARP_HDRLEN (ARP_HDRLEN + 6 + 4 + 6 + 4) |
| |
| #define SHA(ap) ((ap)->arp_sha) |
| #define THA(ap) ((ap)->arp_tha) |
| #define SPA(ap) ((ap)->arp_spa) |
| #define TPA(ap) ((ap)->arp_tpa) |
| |
| /* Compatibility */ |
| #ifndef REVARP_REQUEST |
| #define REVARP_REQUEST 3 |
| #endif |
| #ifndef REVARP_REPLY |
| #define REVARP_REPLY 4 |
| #endif |
| |
| static u_char ezero[6]; |
| |
| void |
| arp_print(register 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; |
| |
| ap = (struct ether_arp *)bp; |
| if ((u_char *)(ap + 1) > snapend) { |
| printf("[|arp]"); |
| return; |
| } |
| if (length < ETHER_ARP_HDRLEN) { |
| (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); |
| |
| if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) |
| || ap->arp_hln != sizeof(SHA(ap)) |
| || ap->arp_pln != sizeof(SPA(ap))) { |
| (void)printf("arp-#%d for proto #%d (%d) hardware #%d (%d)", |
| op, pro, ap->arp_pln, |
| hrd, ap->arp_hln); |
| 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))); |
| (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))); |
| break; |
| |
| case REVARP_REQUEST: |
| (void)printf("rarp who-is %s tell %s", |
| etheraddr_string(THA(ap)), |
| etheraddr_string(SHA(ap))); |
| break; |
| |
| case REVARP_REPLY: |
| (void)printf("rarp reply %s at %s", |
| etheraddr_string(THA(ap)), |
| ipaddr_string(TPA(ap))); |
| break; |
| |
| default: |
| (void)printf("arp-#%d", op); |
| default_print((u_char *)ap, caplen); |
| return; |
| } |
| if (hrd != ARPHRD_ETHER) |
| printf(" hardware #%d", hrd); |
| } |