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/*
* 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.
*/
/* \summary: Address Resolution Protocol (ARP) printer */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-stdinc.h"
#include <string.h>
#include "netdissect.h"
#include "addrtoname.h"
#include "ethertype.h"
#include "extract.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 arp_pkthdr {
nd_uint16_t 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_ATM2225 19 /* ATM (RFC 2225) */
#define ARPHRD_STRIP 23 /* Ricochet Starmode Radio hardware format */
#define ARPHRD_IEEE1394 24 /* IEEE 1394 (FireWire) hardware format */
nd_uint16_t ar_pro; /* format of protocol address */
nd_uint8_t ar_hln; /* length of hardware address */
nd_uint8_t ar_pln; /* length of protocol address */
nd_uint16_t 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 */
#define ARPOP_NAK 10 /* NAK - only valif for ATM ARP */
/*
* The remaining fields are variable in size,
* according to the sizes above.
*/
#ifdef COMMENT_ONLY
nd_byte ar_sha[]; /* sender hardware address */
nd_byte ar_spa[]; /* sender protocol address */
nd_byte ar_tha[]; /* target hardware address */
nd_byte ar_tpa[]; /* target protocol address */
#endif
#define ar_sha(ap) (((const u_char *)((ap)+1))+ 0)
#define ar_spa(ap) (((const u_char *)((ap)+1))+ EXTRACT_U_1((ap)->ar_hln))
#define ar_tha(ap) (((const u_char *)((ap)+1))+ EXTRACT_U_1((ap)->ar_hln)+EXTRACT_U_1((ap)->ar_pln))
#define ar_tpa(ap) (((const u_char *)((ap)+1))+2*EXTRACT_U_1((ap)->ar_hln)+EXTRACT_U_1((ap)->ar_pln))
};
#define ARP_HDRLEN 8
#define HRD(ap) EXTRACT_BE_U_2((ap)->ar_hrd)
#define HRD_LEN(ap) EXTRACT_U_1((ap)->ar_hln)
#define PROTO_LEN(ap) EXTRACT_U_1((ap)->ar_pln)
#define OP(ap) EXTRACT_BE_U_2((ap)->ar_op)
#define PRO(ap) EXTRACT_BE_U_2((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 const struct tok arpop_values[] = {
{ ARPOP_REQUEST, "Request" },
{ ARPOP_REPLY, "Reply" },
{ ARPOP_REVREQUEST, "Reverse Request" },
{ ARPOP_REVREPLY, "Reverse Reply" },
{ ARPOP_INVREQUEST, "Inverse Request" },
{ ARPOP_INVREPLY, "Inverse Reply" },
{ ARPOP_NAK, "NACK Reply" },
{ 0, NULL }
};
static const struct tok arphrd_values[] = {
{ ARPHRD_ETHER, "Ethernet" },
{ ARPHRD_IEEE802, "TokenRing" },
{ ARPHRD_ARCNET, "ArcNet" },
{ ARPHRD_FRELAY, "FrameRelay" },
{ ARPHRD_STRIP, "Strip" },
{ ARPHRD_IEEE1394, "IEEE 1394" },
{ ARPHRD_ATM2225, "ATM" },
{ 0, NULL }
};
/*
* ATM Address Resolution Protocol.
*
* See RFC 2225 for protocol description. ATMARP packets are similar
* to ARP packets, except that there are no length fields for the
* protocol address - instead, there are type/length fields for
* the ATM number and subaddress - and the hardware addresses consist
* of an ATM number and an ATM subaddress.
*/
struct atmarp_pkthdr {
nd_uint16_t aar_hrd; /* format of hardware address */
nd_uint16_t aar_pro; /* format of protocol address */
nd_uint8_t aar_shtl; /* length of source ATM number */
nd_uint8_t aar_sstl; /* length of source ATM subaddress */
#define ATMARP_IS_E164 0x40 /* bit in type/length for E.164 format */
#define ATMARP_LEN_MASK 0x3F /* length of {sub}address in type/length */
nd_uint16_t aar_op; /* same as regular ARP */
nd_uint8_t aar_spln; /* length of source protocol address */
nd_uint8_t aar_thtl; /* length of target ATM number */
nd_uint8_t aar_tstl; /* length of target ATM subaddress */
nd_uint8_t aar_tpln; /* length of target protocol address */
/*
* The remaining fields are variable in size,
* according to the sizes above.
*/
#ifdef COMMENT_ONLY
nd_byte aar_sha[]; /* source ATM number */
nd_byte aar_ssa[]; /* source ATM subaddress */
nd_byte aar_spa[]; /* sender protocol address */
nd_byte aar_tha[]; /* target ATM number */
nd_byte aar_tsa[]; /* target ATM subaddress */
nd_byte aar_tpa[]; /* target protocol address */
#endif
#define ATMHRD(ap) EXTRACT_BE_U_2((ap)->aar_hrd)
#define ATMSHRD_LEN(ap) (EXTRACT_U_1((ap)->aar_shtl) & ATMARP_LEN_MASK)
#define ATMSSLN(ap) (EXTRACT_U_1((ap)->aar_sstl) & ATMARP_LEN_MASK)
#define ATMSPROTO_LEN(ap) EXTRACT_U_1((ap)->aar_spln)
#define ATMOP(ap) EXTRACT_BE_U_2((ap)->aar_op)
#define ATMPRO(ap) EXTRACT_BE_U_2((ap)->aar_pro)
#define ATMTHRD_LEN(ap) (EXTRACT_U_1((ap)->aar_thtl) & ATMARP_LEN_MASK)
#define ATMTSLN(ap) (EXTRACT_U_1((ap)->aar_tstl) & ATMARP_LEN_MASK)
#define ATMTPROTO_LEN(ap) EXTRACT_U_1((ap)->aar_tpln)
#define aar_sha(ap) ((const u_char *)((ap)+1))
#define aar_ssa(ap) (aar_sha(ap) + ATMSHRD_LEN(ap))
#define aar_spa(ap) (aar_ssa(ap) + ATMSSLN(ap))
#define aar_tha(ap) (aar_spa(ap) + ATMSPROTO_LEN(ap))
#define aar_tsa(ap) (aar_tha(ap) + ATMTHRD_LEN(ap))
#define aar_tpa(ap) (aar_tsa(ap) + ATMTSLN(ap))
};
#define ATMSHA(ap) (aar_sha(ap))
#define ATMSSA(ap) (aar_ssa(ap))
#define ATMSPA(ap) (aar_spa(ap))
#define ATMTHA(ap) (aar_tha(ap))
#define ATMTSA(ap) (aar_tsa(ap))
#define ATMTPA(ap) (aar_tpa(ap))
static int
isnonzero(const u_char *a, size_t len)
{
while (len > 0) {
if (EXTRACT_U_1(a) != 0)
return (1);
a++;
len--;
}
return (0);
}
static void
tpaddr_print_ip(netdissect_options *ndo,
const struct arp_pkthdr *ap, u_short pro)
{
if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
ND_PRINT("<wrong proto type>");
else if (PROTO_LEN(ap) != 4)
ND_PRINT("<wrong len>");
else
ND_PRINT("%s", ipaddr_string(ndo, TPA(ap)));
}
static void
spaddr_print_ip(netdissect_options *ndo,
const struct arp_pkthdr *ap, u_short pro)
{
if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
ND_PRINT("<wrong proto type>");
else if (PROTO_LEN(ap) != 4)
ND_PRINT("<wrong len>");
else
ND_PRINT("%s", ipaddr_string(ndo, SPA(ap)));
}
static void
atmarp_addr_print(netdissect_options *ndo,
const u_char *ha, u_int ha_len, const u_char *srca,
u_int srca_len)
{
if (ha_len == 0)
ND_PRINT("<No address>");
else {
ND_PRINT("%s", linkaddr_string(ndo, ha, LINKADDR_ATM, ha_len));
if (srca_len != 0)
ND_PRINT(",%s",
linkaddr_string(ndo, srca, LINKADDR_ATM, srca_len));
}
}
static void
atmarp_tpaddr_print(netdissect_options *ndo,
const struct atmarp_pkthdr *ap, u_short pro)
{
if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
ND_PRINT("<wrong proto type>");
else if (ATMTPROTO_LEN(ap) != 4)
ND_PRINT("<wrong tplen>");
else
ND_PRINT("%s", ipaddr_string(ndo, ATMTPA(ap)));
}
static void
atmarp_spaddr_print(netdissect_options *ndo,
const struct atmarp_pkthdr *ap, u_short pro)
{
if (pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL)
ND_PRINT("<wrong proto type>");
else if (ATMSPROTO_LEN(ap) != 4)
ND_PRINT("<wrong splen>");
else
ND_PRINT("%s", ipaddr_string(ndo, ATMSPA(ap)));
}
static void
atmarp_print(netdissect_options *ndo,
const u_char *bp, u_int length, u_int caplen)
{
const struct atmarp_pkthdr *ap;
u_short pro, hrd, op;
ap = (const struct atmarp_pkthdr *)bp;
ND_TCHECK_SIZE(ap);
hrd = ATMHRD(ap);
pro = ATMPRO(ap);
op = ATMOP(ap);
if (!ND_TTEST_LEN(aar_tpa(ap), ATMTPROTO_LEN(ap))) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)ap, length);
return;
}
if (!ndo->ndo_eflag) {
ND_PRINT("ARP, ");
}
if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
ATMSPROTO_LEN(ap) != 4 ||
ATMTPROTO_LEN(ap) != 4 ||
ndo->ndo_vflag) {
ND_PRINT("%s, %s (len %u/%u)",
tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
ATMSPROTO_LEN(ap),
ATMTPROTO_LEN(ap));
/* don't know know about the address formats */
if (!ndo->ndo_vflag) {
goto out;
}
}
/* print operation */
ND_PRINT("%s%s ",
ndo->ndo_vflag ? ", " : "",
tok2str(arpop_values, "Unknown (%u)", op));
switch (op) {
case ARPOP_REQUEST:
ND_PRINT("who-has ");
atmarp_tpaddr_print(ndo, ap, pro);
if (ATMTHRD_LEN(ap) != 0) {
ND_PRINT(" (");
atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap),
ATMTSA(ap), ATMTSLN(ap));
ND_PRINT(")");
}
ND_PRINT(" tell ");
atmarp_spaddr_print(ndo, ap, pro);
break;
case ARPOP_REPLY:
atmarp_spaddr_print(ndo, ap, pro);
ND_PRINT(" is-at ");
atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
ATMSSLN(ap));
break;
case ARPOP_INVREQUEST:
ND_PRINT("who-is ");
atmarp_addr_print(ndo, ATMTHA(ap), ATMTHRD_LEN(ap), ATMTSA(ap),
ATMTSLN(ap));
ND_PRINT(" tell ");
atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
ATMSSLN(ap));
break;
case ARPOP_INVREPLY:
atmarp_addr_print(ndo, ATMSHA(ap), ATMSHRD_LEN(ap), ATMSSA(ap),
ATMSSLN(ap));
ND_PRINT("at ");
atmarp_spaddr_print(ndo, ap, pro);
break;
case ARPOP_NAK:
ND_PRINT("for ");
atmarp_spaddr_print(ndo, ap, pro);
break;
default:
ND_DEFAULTPRINT((const u_char *)ap, caplen);
return;
}
out:
ND_PRINT(", length %u", length);
return;
trunc:
nd_print_trunc(ndo);
}
void
arp_print(netdissect_options *ndo,
const u_char *bp, u_int length, u_int caplen)
{
const struct arp_pkthdr *ap;
u_short pro, hrd, op, linkaddr;
ndo->ndo_protocol = "arp";
ap = (const struct arp_pkthdr *)bp;
ND_TCHECK_SIZE(ap);
hrd = HRD(ap);
pro = PRO(ap);
op = OP(ap);
/* if its ATM then call the ATM ARP printer
for Frame-relay ARP most of the fields
are similar to Ethernet so overload the Ethernet Printer
and set the linkaddr type for linkaddr_string(ndo, ) accordingly */
switch(hrd) {
case ARPHRD_ATM2225:
atmarp_print(ndo, bp, length, caplen);
return;
case ARPHRD_FRELAY:
linkaddr = LINKADDR_FRELAY;
break;
default:
linkaddr = LINKADDR_ETHER;
break;
}
if (!ND_TTEST_LEN(TPA(ap), PROTO_LEN(ap))) {
nd_print_trunc(ndo);
ND_DEFAULTPRINT((const u_char *)ap, length);
return;
}
if (!ndo->ndo_eflag) {
ND_PRINT("ARP, ");
}
/* print hardware type/len and proto type/len */
if ((pro != ETHERTYPE_IP && pro != ETHERTYPE_TRAIL) ||
PROTO_LEN(ap) != 4 ||
HRD_LEN(ap) == 0 ||
ndo->ndo_vflag) {
ND_PRINT("%s (len %u), %s (len %u)",
tok2str(arphrd_values, "Unknown Hardware (%u)", hrd),
HRD_LEN(ap),
tok2str(ethertype_values, "Unknown Protocol (0x%04x)", pro),
PROTO_LEN(ap));
/* don't know know about the address formats */
if (!ndo->ndo_vflag) {
goto out;
}
}
/* print operation */
ND_PRINT("%s%s ",
ndo->ndo_vflag ? ", " : "",
tok2str(arpop_values, "Unknown (%u)", op));
switch (op) {
case ARPOP_REQUEST:
ND_PRINT("who-has ");
tpaddr_print_ip(ndo, ap, pro);
if (isnonzero((const u_char *)THA(ap), HRD_LEN(ap)))
ND_PRINT(" (%s)",
linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)));
ND_PRINT(" tell ");
spaddr_print_ip(ndo, ap, pro);
break;
case ARPOP_REPLY:
spaddr_print_ip(ndo, ap, pro);
ND_PRINT(" is-at %s",
linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)));
break;
case ARPOP_REVREQUEST:
ND_PRINT("who-is %s tell %s",
linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)));
break;
case ARPOP_REVREPLY:
ND_PRINT("%s at ",
linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)));
tpaddr_print_ip(ndo, ap, pro);
break;
case ARPOP_INVREQUEST:
ND_PRINT("who-is %s tell %s",
linkaddr_string(ndo, THA(ap), linkaddr, HRD_LEN(ap)),
linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)));
break;
case ARPOP_INVREPLY:
ND_PRINT("%s at ",
linkaddr_string(ndo, SHA(ap), linkaddr, HRD_LEN(ap)));
spaddr_print_ip(ndo, ap, pro);
break;
default:
ND_DEFAULTPRINT((const u_char *)ap, caplen);
return;
}
out:
ND_PRINT(", length %u", length);
return;
trunc:
nd_print_trunc(ndo);
}