NetBSD/sys/lib/libsa/arp.c

229 lines
6.1 KiB
C

/* $NetBSD: arp.c,v 1.6 1995/08/04 01:17:26 thorpej Exp $ */
/*
* 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.
*
* @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL)
*/
#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 size_t arpsend __P((struct iodesc *, void *, size_t));
static size_t arprecv __P((struct iodesc *, void *, size_t, time_t));
/* 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 {
struct ether_arp arp;
u_char pad[18]; /* 60 - sizeof(arp) */
} data;
} wbuf;
struct {
u_char header[ETHER_SIZE];
struct {
struct ether_arp arp;
u_char pad[24]; /* extra space */
} data;
} 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
bzero((char*)&wbuf.data, sizeof(wbuf.data));
ah = &wbuf.data.arp;
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, &wbuf.data, sizeof(wbuf.data),
arprecv, &rbuf.data, sizeof(rbuf.data));
/* Store ethernet address in cache */
MACPY(rbuf.data.arp.arp_sha, al->ea);
++arp_num;
return (al->ea);
}
static size_t
arpsend(d, pkt, len)
register struct iodesc *d;
register void *pkt;
register size_t 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 size_t
arprecv(d, pkt, len, tleft)
register struct iodesc *d;
register void *pkt;
register size_t len;
time_t tleft;
{
register struct ether_header *eh;
register struct ether_arp *ah;
#ifdef ARP_DEBUG
if (debug)
printf("arprecv: ");
#endif
len = readether(d, pkt, len, tleft);
if (len == -1 || len < sizeof(struct ether_arp)) {
#ifdef ARP_DEBUG
if (debug)
printf("bad len=%d\n", len);
#endif
goto bad;
}
eh = (struct ether_header *)pkt - 1;
if (eh->ether_type != htons(ETHERTYPE_ARP)) {
#ifdef ARP_DEBUG
if (debug)
printf("not arp %d\n", ntohs(eh->ether_type));
#endif
goto bad;
}
/* 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("not ours %s\n", ether_sprintf(eh->ether_dhost));
#endif
goto bad;
}
ah = (struct ether_arp *)pkt;
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("not valid reply\n");
#endif
goto bad;
}
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("already cached??\n");
#endif
goto bad;
}
#ifdef ARP_DEBUG
if (debug)
printf("cacheing %s --> %s\n",
intoa(ah->arp_spa),
ether_sprintf(ah->arp_sha));
#endif
return (0);
bad:
errno = 0;
return (-1);
}