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Implement full proxy ARP, gated on option ARP_PROXYALL. This allows

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a FreeBSD box to do proxy ARP as easily as most commercial routers do,
without messing around with (potentially variable) Ethernet addresses.
This code is really quite simple; I'm not at all sure why it wasn't
implemented in 4.4.

It might be worth stealing an interface flag (maybe IFF_LINK1) to use for
finer-grained control over which interfaces get proxy treatment.  For the
moment, it's all or nothing.
This commit is contained in:
Garrett Wollman 1994-10-01 21:50:33 +00:00
parent 470d929ec2
commit 28e822955c
1 changed files with 44 additions and 7 deletions
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51
sys/netinet/if_ether.c
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@ -31,7 +31,7 @@
* SUCH DAMAGE.
*
* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
* $Id: if_ether.c,v 1.2 1994/08/02 07:47:59 davidg Exp $
* $Id: if_ether.c,v 1.3 1994/08/18 22:35:26 wollman Exp $
*/
/*
@ -92,6 +92,10 @@ int arp_maxtries = 5;
int useloopback = 1; /* use loopback interface for local traffic */
int arpinit_done = 0;
#ifdef ARP_PROXYALL
int arp_proxyall = 1;
#endif
/*
* Timeout routine. Age arp_tab entries periodically.
*/
@ -475,13 +479,46 @@ in_arpinput(m)
sizeof(ea->arp_sha));
} else {
la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
if (la == NULL)
if (la == NULL) {
#ifdef ARP_PROXYALL
struct sockaddr_in sin;
if(!arp_proxyall) goto out;
bzero(&sin, sizeof sin);
sin.sin_family = AF_INET;
sin.sin_len = sizeof sin;
sin.sin_addr = itaddr;
rt = rtalloc1((struct sockaddr *)&sin, 0);
if( !rt )
goto out;
/*
* Don't send proxies for nodes on the same interface
* as this one came out of, or we'll get into a fight
* over who claims what Ether address.
*/
if(rt->rt_ifp == &ac->ac_if) {
rtfree(rt);
goto out;
}
bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
sizeof(ea->arp_sha));
bcopy(ac->ac_enaddr, (caddr_t)ea->arp_sha,
sizeof(ea->arp_sha));
rtfree(rt);
printf("arp: proxying for %x\n", ntohl(itaddr.s_addr));
#else
goto out;
rt = la->la_rt;
bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
sizeof(ea->arp_sha));
sdl = SDL(rt->rt_gateway);
bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
#endif
} else {
rt = la->la_rt;
bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
sizeof(ea->arp_sha));
sdl = SDL(rt->rt_gateway);
bcopy(LLADDR(sdl), (caddr_t)ea->arp_sha,
sizeof(ea->arp_sha));
}
}
bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa));