NetBSD/sys/lib/libsa/arp.c

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/*
* Copyright (c) 1992 Regents of the University of California.
* All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Lawrence Berkeley Laboratory and its contributors.
* 4. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL)
* $Id: arp.c,v 1.2 1994/08/04 19:39:34 brezak Exp $
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/in_systm.h>
#include <string.h>
#include "stand.h"
#include "net.h"
/* Cache stuff */
#define ARP_NUM 8 /* need at most 3 arp entries */
static struct arp_list {
n_long addr;
u_char ea[6];
} arp_list[ARP_NUM] = {
{ INADDR_BROADCAST, BA }
};
static int arp_num = 1;
/* Local forwards */
static int arpsend __P((struct iodesc *, void *, int));
static int arprecv __P((struct iodesc *, void *, int));
/* Broadcast an ARP packet, asking who has addr on interface d */
u_char *
arpwhohas(d, addr)
register struct iodesc *d;
n_long addr;
{
register int i;
register struct ether_arp *ah;
register struct arp_list *al;
struct {
u_char header[ETHER_SIZE];
struct ether_arp warp;
} wbuf;
union {
u_char buffer[RECV_SIZE];
struct {
u_char header[ETHER_SIZE];
struct ether_arp rarp;
} ru;
} rbuf;
#ifdef ARP_DEBUG
if (debug)
printf("arpwhohas: called for %s\n", intoa(addr));
#endif
/* Try for cached answer first */
for (i = 0, al = arp_list; i < arp_num; ++i, ++al)
if (addr == al->addr)
return (al->ea);
/* Don't overflow cache */
if (arp_num > ARP_NUM - 1)
panic("arpwhohas: overflowed arp_list!");
#ifdef ARP_DEBUG
if (debug)
printf("arpwhohas: not cached\n");
#endif
ah = &wbuf.warp;
bzero(ah, sizeof(*ah));
ah->arp_hrd = htons(ARPHRD_ETHER);
ah->arp_pro = htons(ETHERTYPE_IP);
ah->arp_hln = sizeof(ah->arp_sha); /* hardware address length */
ah->arp_pln = sizeof(ah->arp_spa); /* protocol address length */
ah->arp_op = htons(ARPOP_REQUEST);
MACPY(d->myea, ah->arp_sha);
bcopy(&d->myip, ah->arp_spa, sizeof(ah->arp_spa));
bcopy(&addr, ah->arp_tpa, sizeof(ah->arp_tpa));
/* Store ip address in cache */
al->addr = addr;
(void)sendrecv(d, arpsend, ah, sizeof(*ah), arprecv,
((u_char *)&rbuf.ru.rarp) - ETHER_SIZE,
ETHER_SIZE + sizeof(rbuf.ru.rarp));
/* Store ethernet address in cache */
MACPY(rbuf.ru.rarp.arp_sha, al->ea);
++arp_num;
#ifdef ARP_DEBUG
if (debug)
printf("arpwhohas: cacheing %s --> %s\n", intoa(addr), ether_sprintf(al->ea));
#endif
return (al->ea);
}
static int
arpsend(d, pkt, len)
register struct iodesc *d;
register void *pkt;
register int len;
{
#ifdef ARP_DEBUG
if (debug)
printf("arpsend: called\n");
#endif
return (sendether(d, pkt, len, bcea, ETHERTYPE_ARP));
}
/* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */
static int
arprecv(d, pkt, len)
register struct iodesc *d;
register void *pkt;
register int len;
{
register struct ether_header *eh;
register struct ether_arp *ah;
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: called\n");
#endif
if (len < sizeof(*eh) + sizeof(*ah)) {
errno = 0;
return (-1);
}
eh = (struct ether_header *)pkt;
/* Must be to us */
if (bcmp(d->myea, eh->ether_dhost, 6) != 0 &&
bcmp(bcea, eh->ether_dhost, 6) != 0) {
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: not ours %s\n", ether_sprintf(eh->ether_dhost));
#endif
errno = 0;
return (-1);
}
if (ntohs(eh->ether_type) != ETHERTYPE_ARP) {
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: not arp %d\n", ntohs(eh->ether_type));
#endif
errno = 0;
return (-1);
}
ah = (struct ether_arp *)(eh + 1);
HTONS(ah->arp_hrd);
HTONS(ah->arp_pro);
HTONS(ah->arp_op);
if (ah->arp_hrd != ARPHRD_ETHER || ah->arp_pro != ETHERTYPE_IP ||
ah->arp_hln != sizeof(ah->arp_sha) ||
ah->arp_pln != sizeof(ah->arp_spa) || ah->arp_op != ARPOP_REPLY) {
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: not valid reply\n");
#endif
errno = 0;
return (-1);
}
if (bcmp(&arp_list[arp_num].addr, ah->arp_spa, sizeof(long)) != 0 ||
bcmp(&d->myip, ah->arp_tpa, sizeof(d->myip)) != 0) {
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: already cached??\n");
#endif
errno = 0;
return (-1);
}
return (0);
}