partial sync with netbsd 960418, more to come

1 files changed, 903 insertions, 0 deletions

diff --git a/sys/netinet/if_arp.c b/sys/netinet/if_arp.c
new file mode 100644
index 00000000000..deafb294d68
--- /dev/null
+++ b/sys/netinet/if_arp.c
@@ -0,0 +1,903 @@
+/*	$NetBSD: if_arp.c,v 1.29 1996/03/30 21:53:19 christos Exp $	*/
+
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	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 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, Berkeley 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.
+ *
+ *	@(#)if_ether.c	8.1 (Berkeley) 6/10/93
+ */
+
+/*
+ * Ethernet address resolution protocol.
+ * TODO:
+ *	add "inuse/lock" bit (or ref. count) along with valid bit
+ */
+
+#ifdef INET
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/time.h>
+#include <sys/kernel.h>
+#include <sys/errno.h>
+#include <sys/ioctl.h>
+#include <sys/syslog.h>
+#include <sys/proc.h>
+
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/in_var.h>
+#include <netinet/ip.h>
+#include <netinet/if_ether.h>
+
+#define SIN(s) ((struct sockaddr_in *)s)
+#define SDL(s) ((struct sockaddr_dl *)s)
+#define SRP(s) ((struct sockaddr_inarp *)s)
+
+/*
+ * ARP trailer negotiation.  Trailer protocol is not IP specific,
+ * but ARP request/response use IP addresses.
+ */
+#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
+
+/* timer values */
+int	arpt_prune = (5*60*1);	/* walk list every 5 minutes */
+int	arpt_keep = (20*60);	/* once resolved, good for 20 more minutes */
+int	arpt_down = 20;		/* once declared down, don't send for 20 secs */
+#define	rt_expire rt_rmx.rmx_expire
+
+static	void arprequest
+	    __P((struct arpcom *, u_int32_t *, u_int32_t *, u_int8_t *));
+static	void arptfree __P((struct llinfo_arp *));
+static	void arptimer __P((void *));
+static	struct llinfo_arp *arplookup __P((u_int32_t, int, int));
+static	void in_arpinput __P((struct mbuf *));
+
+extern	struct ifnet loif;
+LIST_HEAD(, llinfo_arp) llinfo_arp;
+struct	ifqueue arpintrq = {0, 0, 0, 50};
+int	arp_inuse, arp_allocated, arp_intimer;
+int	arp_maxtries = 5;
+int	useloopback = 1;	/* use loopback interface for local traffic */
+int	arpinit_done = 0;
+
+/* revarp state */
+static struct	in_addr myip, srv_ip;
+static int	myip_initialized = 0;
+static int	revarp_in_progress = 0;
+static struct	ifnet *myip_ifp = NULL;
+
+static void arptimer __P((void *));
+static void arprequest __P((struct arpcom *, u_int32_t *, u_int32_t *,
+			    u_int8_t *));
+static void in_arpinput __P((struct mbuf *));
+static void arptfree __P((struct llinfo_arp *));
+static struct llinfo_arp *arplookup __P((u_int32_t, int, int ));
+#ifdef DDB
+static void db_print_sa __P((struct sockaddr *));
+static void db_print_ifa __P((struct ifaddr *));
+static void db_print_llinfo __P((caddr_t));
+static int db_show_radix_node __P((struct radix_node *, void *));
+#endif
+
+/*
+ * Timeout routine.  Age arp_tab entries periodically.
+ */
+/* ARGSUSED */
+static void
+arptimer(arg)
+	void *arg;
+{
+	int s;
+	register struct llinfo_arp *la, *nla;
+
+	s = splsoftnet();
+	timeout(arptimer, NULL, arpt_prune * hz);
+	for (la = llinfo_arp.lh_first; la != 0; la = nla) {
+		register struct rtentry *rt = la->la_rt;
+
+		nla = la->la_list.le_next;
+		if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
+			arptfree(la); /* timer has expired; clear */
+	}
+	splx(s);
+}
+
+/*
+ * Parallel to llc_rtrequest.
+ */
+void
+arp_rtrequest(req, rt, sa)
+	int req;
+	register struct rtentry *rt;
+	struct sockaddr *sa;
+{
+	register struct sockaddr *gate = rt->rt_gateway;
+	register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
+	static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
+
+	if (!arpinit_done) {
+		arpinit_done = 1;
+		/*
+		 * We generate expiration times from time.tv_sec
+		 * so avoid accidently creating permanent routes.
+		 */
+		if (time.tv_sec == 0) {
+			time.tv_sec++;
+		}
+		timeout(arptimer, (caddr_t)0, hz);
+	}
+	if (rt->rt_flags & RTF_GATEWAY)
+		return;
+	switch (req) {
+
+	case RTM_ADD:
+		/*
+		 * XXX: If this is a manually added route to interface
+		 * such as older version of routed or gated might provide,
+		 * restore cloning bit.
+		 */
+		if ((rt->rt_flags & RTF_HOST) == 0 &&
+		    SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
+			rt->rt_flags |= RTF_CLONING;
+		if (rt->rt_flags & RTF_CLONING) {
+			/*
+			 * Case 1: This route should come from a route to iface.
+			 */
+			rt_setgate(rt, rt_key(rt),
+					(struct sockaddr *)&null_sdl);
+			gate = rt->rt_gateway;
+			SDL(gate)->sdl_type = rt->rt_ifp->if_type;
+			SDL(gate)->sdl_index = rt->rt_ifp->if_index;
+			/*
+			 * Give this route an expiration time, even though
+			 * it's a "permanent" route, so that routes cloned
+			 * from it do not need their expiration time set.
+			 */
+			rt->rt_expire = time.tv_sec;
+			break;
+		}
+		/* Announce a new entry if requested. */
+		if (rt->rt_flags & RTF_ANNOUNCE)
+			arprequest((struct arpcom *)rt->rt_ifp,
+			    &SIN(rt_key(rt))->sin_addr.s_addr,
+			    &SIN(rt_key(rt))->sin_addr.s_addr,
+			    (u_char *)LLADDR(SDL(gate)));
+		/*FALLTHROUGH*/
+	case RTM_RESOLVE:
+		if (gate->sa_family != AF_LINK ||
+		    gate->sa_len < sizeof(null_sdl)) {
+			log(LOG_DEBUG, "arp_rtrequest: bad gateway value");
+			break;
+		}
+		SDL(gate)->sdl_type = rt->rt_ifp->if_type;
+		SDL(gate)->sdl_index = rt->rt_ifp->if_index;
+		if (la != 0)
+			break; /* This happens on a route change */
+		/*
+		 * Case 2:  This route may come from cloning, or a manual route
+		 * add with a LL address.
+		 */
+		R_Malloc(la, struct llinfo_arp *, sizeof(*la));
+		rt->rt_llinfo = (caddr_t)la;
+		if (la == 0) {
+			log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
+			break;
+		}
+		arp_inuse++, arp_allocated++;
+		Bzero(la, sizeof(*la));
+		la->la_rt = rt;
+		rt->rt_flags |= RTF_LLINFO;
+		LIST_INSERT_HEAD(&llinfo_arp, la, la_list);
+		if (SIN(rt_key(rt))->sin_addr.s_addr ==
+		    (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
+			/*
+			 * This test used to be
+			 *	if (loif.if_flags & IFF_UP)
+			 * It allowed local traffic to be forced through
+			 * the hardware by configuring the loopback down.
+			 * However, it causes problems during network
+			 * configuration for boards that can't receive
+			 * packets they send.  It is now necessary to clear
+			 * "useloopback" and remove the route to force
+			 * traffic out to the hardware.
+			 */
+			rt->rt_expire = 0;
+			Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
+			    LLADDR(SDL(gate)),
+			    SDL(gate)->sdl_alen = ETHER_ADDR_LEN);
+			if (useloopback)
+				rt->rt_ifp = &loif;
+		}
+		break;
+
+	case RTM_DELETE:
+		if (la == 0)
+			break;
+		arp_inuse--;
+		LIST_REMOVE(la, la_list);
+		rt->rt_llinfo = 0;
+		rt->rt_flags &= ~RTF_LLINFO;
+		if (la->la_hold)
+			m_freem(la->la_hold);
+		Free((caddr_t)la);
+	}
+}
+
+/*
+ * Broadcast an ARP packet, asking who has addr on interface ac.
+ */
+void
+arpwhohas(ac, addr)
+	register struct arpcom *ac;
+	register struct in_addr *addr;
+{
+	arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr);
+}
+
+/*
+ * Broadcast an ARP request. Caller specifies:
+ *	- arp header source ip address
+ *	- arp header target ip address
+ *	- arp header source ethernet address
+ */
+static void
+arprequest(ac, sip, tip, enaddr)
+	register struct arpcom *ac;
+	register u_int32_t *sip, *tip;
+	register u_int8_t *enaddr;
+{
+	register struct mbuf *m;
+	register struct ether_header *eh;
+	register struct ether_arp *ea;
+	struct sockaddr sa;
+
+	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
+		return;
+	m->m_len = sizeof(*ea);
+	m->m_pkthdr.len = sizeof(*ea);
+	MH_ALIGN(m, sizeof(*ea));
+	ea = mtod(m, struct ether_arp *);
+	eh = (struct ether_header *)sa.sa_data;
+	bzero((caddr_t)ea, sizeof (*ea));
+	bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
+	    sizeof(eh->ether_dhost));
+	eh->ether_type = htons(ETHERTYPE_ARP);	/* if_output will not swap */
+	ea->arp_hrd = htons(ARPHRD_ETHER);
+	ea->arp_pro = htons(ETHERTYPE_IP);
+	ea->arp_hln = sizeof(ea->arp_sha);	/* hardware address length */
+	ea->arp_pln = sizeof(ea->arp_spa);	/* protocol address length */
+	ea->arp_op = htons(ARPOP_REQUEST);
+	bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
+	bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
+	bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa));
+	sa.sa_family = AF_UNSPEC;
+	sa.sa_len = sizeof(sa);
+	(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
+}
+
+/*
+ * Resolve an IP address into an ethernet address.  If success,
+ * desten is filled in.  If there is no entry in arptab,
+ * set one up and broadcast a request for the IP address.
+ * Hold onto this mbuf and resend it once the address
+ * is finally resolved.  A return value of 1 indicates
+ * that desten has been filled in and the packet should be sent
+ * normally; a 0 return indicates that the packet has been
+ * taken over here, either now or for later transmission.
+ */
+int
+arpresolve(ac, rt, m, dst, desten)
+	register struct arpcom *ac;
+	register struct rtentry *rt;
+	struct mbuf *m;
+	register struct sockaddr *dst;
+	register u_char *desten;
+{
+	register struct llinfo_arp *la;
+	struct sockaddr_dl *sdl;
+
+	if (m->m_flags & M_BCAST) {	/* broadcast */
+		bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,
+		    sizeof(etherbroadcastaddr));
+		return (1);
+	}
+	if (m->m_flags & M_MCAST) {	/* multicast */
+		ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
+		return (1);
+	}
+	if (rt)
+		la = (struct llinfo_arp *)rt->rt_llinfo;
+	else {
+		if ((la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0)) != NULL)
+			rt = la->la_rt;
+	}
+	if (la == 0 || rt == 0) {
+		log(LOG_DEBUG, "arpresolve: can't allocate llinfo");
+		m_freem(m);
+		return (0);
+	}
+	sdl = SDL(rt->rt_gateway);
+	/*
+	 * Check the address family and length is valid, the address
+	 * is resolved; otherwise, try to resolve.
+	 */
+	if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&
+	    sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
+		bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
+		return 1;
+	}
+	/*
+	 * There is an arptab entry, but no ethernet address
+	 * response yet.  Replace the held mbuf with this
+	 * latest one.
+	 */
+	if (la->la_hold)
+		m_freem(la->la_hold);
+	la->la_hold = m;
+	/*
+	 * Re-send the ARP request when appropriate.
+	 */
+#ifdef	DIAGNOSTIC
+	if (rt->rt_expire == 0) {
+		/* This should never happen. (Should it? -gwr) */
+		printf("arpresolve: unresolved and rt_expire == 0\n");
+		/* Set expiration time to now (expired). */
+		rt->rt_expire = time.tv_sec;
+	}
+#endif
+	if (rt->rt_expire) {
+		rt->rt_flags &= ~RTF_REJECT;
+		if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {
+			rt->rt_expire = time.tv_sec;
+			if (la->la_asked++ < arp_maxtries)
+				arpwhohas(ac, &(SIN(dst)->sin_addr));
+			else {
+				rt->rt_flags |= RTF_REJECT;
+				rt->rt_expire += arpt_down;
+				la->la_asked = 0;
+			}
+		}
+	}
+	return (0);
+}
+
+/*
+ * Common length and type checks are done here,
+ * then the protocol-specific routine is called.
+ */
+void
+arpintr()
+{
+	register struct mbuf *m;
+	register struct arphdr *ar;
+	int s;
+
+	while (arpintrq.ifq_head) {
+		s = splimp();
+		IF_DEQUEUE(&arpintrq, m);
+		splx(s);
+		if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
+			panic("arpintr");
+		if (m->m_len >= sizeof(struct arphdr) &&
+		    (ar = mtod(m, struct arphdr *)) &&
+		    ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
+		    m->m_len >=
+		      sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
+			switch (ntohs(ar->ar_pro)) {
+
+			case ETHERTYPE_IP:
+			case ETHERTYPE_IPTRAILERS:
+				in_arpinput(m);
+				continue;
+			}
+		m_freem(m);
+	}
+}
+
+/*
+ * ARP for Internet protocols on 10 Mb/s Ethernet.
+ * Algorithm is that given in RFC 826.
+ * In addition, a sanity check is performed on the sender
+ * protocol address, to catch impersonators.
+ * We no longer handle negotiations for use of trailer protocol:
+ * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
+ * along with IP replies if we wanted trailers sent to us,
+ * and also sent them in response to IP replies.
+ * This allowed either end to announce the desire to receive
+ * trailer packets.
+ * We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
+ * but formerly didn't normally send requests.
+ */
+static void
+in_arpinput(m)
+	struct mbuf *m;
+{
+	register struct ether_arp *ea;
+	register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
+	struct ether_header *eh;
+	register struct llinfo_arp *la = 0;
+	register struct rtentry *rt;
+	struct in_ifaddr *ia, *maybe_ia = 0;
+	struct sockaddr_dl *sdl;
+	struct sockaddr sa;
+	struct in_addr isaddr, itaddr, myaddr;
+	int op;
+
+	ea = mtod(m, struct ether_arp *);
+	op = ntohs(ea->arp_op);
+	bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr));
+	bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr));
+	for (ia = in_ifaddr.tqh_first; ia != 0; ia = ia->ia_list.tqe_next)
+		if (ia->ia_ifp == &ac->ac_if) {
+			maybe_ia = ia;
+			if (itaddr.s_addr == ia->ia_addr.sin_addr.s_addr ||
+			    isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)
+				break;
+		}
+	if (maybe_ia == 0)
+		goto out;
+	myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
+	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
+	    sizeof (ea->arp_sha)))
+		goto out;	/* it's from me, ignore it. */
+	if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
+	    sizeof (ea->arp_sha))) {
+		log(LOG_ERR,
+		    "arp: ether address is broadcast for IP address %x!\n",
+		    ntohl(isaddr.s_addr));
+		goto out;
+	}
+	if (isaddr.s_addr == myaddr.s_addr) {
+		log(LOG_ERR,
+		   "duplicate IP address %08x sent from ethernet address %s\n",
+		   ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha));
+		itaddr = myaddr;
+		goto reply;
+	}
+	la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0);
+	if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) {
+		if (sdl->sdl_alen &&
+		    bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen))
+			log(LOG_INFO, "arp info overwritten for %08x by %s\n",
+			    ntohl(isaddr.s_addr), ether_sprintf(ea->arp_sha));
+		bcopy((caddr_t)ea->arp_sha, LLADDR(sdl),
+		    sdl->sdl_alen = sizeof(ea->arp_sha));
+		if (rt->rt_expire)
+			rt->rt_expire = time.tv_sec + arpt_keep;
+		rt->rt_flags &= ~RTF_REJECT;
+		la->la_asked = 0;
+		if (la->la_hold) {
+			(*ac->ac_if.if_output)(&ac->ac_if, la->la_hold,
+				rt_key(rt), rt);
+			la->la_hold = 0;
+		}
+	}
+reply:
+	if (op != ARPOP_REQUEST) {
+	out:
+		m_freem(m);
+		return;
+	}
+	if (itaddr.s_addr == myaddr.s_addr) {
+		/* I am the target */
+		bcopy((caddr_t)ea->arp_sha, (caddr_t)ea->arp_tha,
+		    sizeof(ea->arp_sha));
+		bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,
+		    sizeof(ea->arp_sha));
+	} else {
+		la = arplookup(itaddr.s_addr, 0, SIN_PROXY);
+		if (la == 0)
+			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));
+	}
+
+	bcopy((caddr_t)ea->arp_spa, (caddr_t)ea->arp_tpa, sizeof(ea->arp_spa));
+	bcopy((caddr_t)&itaddr, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
+	ea->arp_op = htons(ARPOP_REPLY);
+	ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */
+	eh = (struct ether_header *)sa.sa_data;
+	bcopy((caddr_t)ea->arp_tha, (caddr_t)eh->ether_dhost,
+	    sizeof(eh->ether_dhost));
+	eh->ether_type = htons(ETHERTYPE_ARP);
+	sa.sa_family = AF_UNSPEC;
+	sa.sa_len = sizeof(sa);
+	(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
+	return;
+}
+
+/*
+ * Free an arp entry.
+ */
+static void
+arptfree(la)
+	register struct llinfo_arp *la;
+{
+	register struct rtentry *rt = la->la_rt;
+	register struct sockaddr_dl *sdl;
+
+	if (rt == 0)
+		panic("arptfree");
+	if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) &&
+	    sdl->sdl_family == AF_LINK) {
+		sdl->sdl_alen = 0;
+		la->la_asked = 0;
+		rt->rt_flags &= ~RTF_REJECT;
+		return;
+	}
+	rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt),
+	    0, (struct rtentry **)0);
+}
+
+/*
+ * Lookup or enter a new address in arptab.
+ */
+static struct llinfo_arp *
+arplookup(addr, create, proxy)
+	u_int32_t addr;
+	int create, proxy;
+{
+	register struct rtentry *rt;
+	static struct sockaddr_inarp sin;
+
+	sin.sin_len = sizeof(sin);
+	sin.sin_family = AF_INET;
+	sin.sin_addr.s_addr = addr;
+	sin.sin_other = proxy ? SIN_PROXY : 0;
+	rt = rtalloc1(sintosa(&sin), create);
+	if (rt == 0)
+		return (0);
+	rt->rt_refcnt--;
+	if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 ||
+	    rt->rt_gateway->sa_family != AF_LINK) {
+		if (create)
+			log(LOG_DEBUG, "arplookup: unable to enter address for %x\n", ntohl(addr));
+		return (0);
+	}
+	return ((struct llinfo_arp *)rt->rt_llinfo);
+}
+
+int
+arpioctl(cmd, data)
+	u_long cmd;
+	caddr_t data;
+{
+
+	return (EOPNOTSUPP);
+}
+
+void
+arp_ifinit(ac, ifa)
+	struct arpcom *ac;
+	struct ifaddr *ifa;
+{
+
+	ac->ac_ipaddr = IA_SIN(ifa)->sin_addr;
+	/* Warn the user if another station has this IP address. */
+	arpwhohas(ac, &ac->ac_ipaddr);
+	ifa->ifa_rtrequest = arp_rtrequest;
+	ifa->ifa_flags |= RTF_CLONING;
+}
+
+/*
+ * Called from 10 Mb/s Ethernet interrupt handlers
+ * when ether packet type ETHERTYPE_REVARP
+ * is received.  Common length and type checks are done here,
+ * then the protocol-specific routine is called.
+ */
+void
+revarpinput(m)
+	struct mbuf *m;
+{
+	struct arphdr *ar;
+
+	if (m->m_len < sizeof(struct arphdr))
+		goto out;
+	ar = mtod(m, struct arphdr *);
+	if (ntohs(ar->ar_hrd) != ARPHRD_ETHER)
+		goto out;
+	if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln))
+		goto out;
+	switch (ntohs(ar->ar_pro)) {
+
+	case ETHERTYPE_IP:
+	case ETHERTYPE_IPTRAILERS:
+		in_revarpinput(m);
+		return;
+
+	default:
+		break;
+	}
+out:
+	m_freem(m);
+}
+
+/*
+ * RARP for Internet protocols on 10 Mb/s Ethernet.
+ * Algorithm is that given in RFC 903.
+ * We are only using for bootstrap purposes to get an ip address for one of
+ * our interfaces.  Thus we support no user-interface.
+ *
+ * Since the contents of the RARP reply are specific to the interface that
+ * sent the request, this code must ensure that they are properly associated.
+ *
+ * Note: also supports ARP via RARP packets, per the RFC.
+ */
+void
+in_revarpinput(m)
+	struct mbuf *m;
+{
+	struct ifnet *ifp;
+	struct ether_arp *ar;
+	int op;
+
+	ar = mtod(m, struct ether_arp *);
+	op = ntohs(ar->arp_op);
+	switch (op) {
+	case ARPOP_REQUEST:
+	case ARPOP_REPLY:	/* per RFC */
+		in_arpinput(m);
+		return;
+	case ARPOP_REVREPLY:
+		break;
+	case ARPOP_REVREQUEST:	/* handled by rarpd(8) */
+	default:
+		goto out;
+	}
+	if (!revarp_in_progress)
+		goto out;
+	ifp = m->m_pkthdr.rcvif;
+	if (ifp != myip_ifp) /* !same interface */
+		goto out;
+	if (myip_initialized)
+		goto wake;
+	if (bcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr,
+	    sizeof(ar->arp_tha)))
+		goto out;
+	bcopy((caddr_t)ar->arp_spa, (caddr_t)&srv_ip, sizeof(srv_ip));
+	bcopy((caddr_t)ar->arp_tpa, (caddr_t)&myip, sizeof(myip));
+	myip_initialized = 1;
+wake:	/* Do wakeup every time in case it was missed. */
+	wakeup((caddr_t)&myip);
+
+out:
+	m_freem(m);
+}
+
+/*
+ * Send a RARP request for the ip address of the specified interface.
+ * The request should be RFC 903-compliant.
+ */
+void
+revarprequest(ifp)
+	struct ifnet *ifp;
+{
+	struct sockaddr sa;
+	struct mbuf *m;
+	struct ether_header *eh;
+	struct ether_arp *ea;
+	struct arpcom *ac = (struct arpcom *)ifp;
+
+	if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
+		return;
+	m->m_len = sizeof(*ea);
+	m->m_pkthdr.len = sizeof(*ea);
+	MH_ALIGN(m, sizeof(*ea));
+	ea = mtod(m, struct ether_arp *);
+	eh = (struct ether_header *)sa.sa_data;
+	bzero((caddr_t)ea, sizeof(*ea));
+	bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
+	    sizeof(eh->ether_dhost));
+	eh->ether_type = htons(ETHERTYPE_REVARP);
+	ea->arp_hrd = htons(ARPHRD_ETHER);
+	ea->arp_pro = htons(ETHERTYPE_IP);
+	ea->arp_hln = sizeof(ea->arp_sha);	/* hardware address length */
+	ea->arp_pln = sizeof(ea->arp_spa);	/* protocol address length */
+	ea->arp_op = htons(ARPOP_REVREQUEST);
+	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_sha,
+	   sizeof(ea->arp_sha));
+	bcopy((caddr_t)ac->ac_enaddr, (caddr_t)ea->arp_tha,
+	   sizeof(ea->arp_tha));
+	sa.sa_family = AF_UNSPEC;
+	sa.sa_len = sizeof(sa);
+	ifp->if_output(ifp, m, &sa, (struct rtentry *)0);
+}
+
+/*
+ * RARP for the ip address of the specified interface, but also
+ * save the ip address of the server that sent the answer.
+ * Timeout if no response is received.
+ */
+int
+revarpwhoarewe(ifp, serv_in, clnt_in)
+	struct ifnet *ifp;
+	struct in_addr *serv_in;
+	struct in_addr *clnt_in;
+{
+	int result, count = 20;
+	
+	if (myip_initialized) 
+		return EIO;
+
+	myip_ifp = ifp;
+	revarp_in_progress = 1;
+	while (count--) {
+		revarprequest(ifp);
+		result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2);
+		if (result != EWOULDBLOCK)
+			break;
+	}
+	revarp_in_progress = 0;
+	if (!myip_initialized)
+		return ENETUNREACH;
+	
+	bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in));
+	bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in));
+	return 0;
+}
+
+/* For compatibility: only saves interface address. */
+int
+revarpwhoami(in, ifp)
+	struct in_addr *in;
+	struct ifnet *ifp;
+{
+	struct in_addr server;
+	return (revarpwhoarewe(ifp, &server, in));
+}
+
+
+#ifdef DDB
+
+#include <machine/db_machdep.h>
+#include <ddb/db_interface.h>
+#include <ddb/db_output.h>
+static void
+db_print_sa(sa)
+	struct sockaddr *sa;
+{
+	int len;
+	u_char *p;
+
+	if (sa == 0) {
+		db_printf("[NULL]");
+		return;
+	}
+
+	p = (u_char*)sa;
+	len = sa->sa_len;
+	db_printf("[");
+	while (len > 0) {
+		db_printf("%d", *p);
+		p++; len--;
+		if (len) db_printf(",");
+	}
+	db_printf("]\n");
+}
+static void
+db_print_ifa(ifa)
+	struct ifaddr *ifa;
+{
+	if (ifa == 0)
+		return;
+	db_printf("  ifa_addr=");
+	db_print_sa(ifa->ifa_addr);
+	db_printf("  ifa_dsta=");
+	db_print_sa(ifa->ifa_dstaddr);
+	db_printf("  ifa_mask=");
+	db_print_sa(ifa->ifa_netmask);
+	db_printf("  flags=0x%x,refcnt=%d,metric=%d\n",
+			  ifa->ifa_flags,
+			  ifa->ifa_refcnt,
+			  ifa->ifa_metric);
+}
+static void
+db_print_llinfo(li)
+	caddr_t li;
+{
+	struct llinfo_arp *la;
+
+	if (li == 0)
+		return;
+	la = (struct llinfo_arp *)li;
+	db_printf("  la_rt=%p la_hold=%p, la_asked=0x%lx\n",
+			  la->la_rt, la->la_hold, la->la_asked);
+}
+/*
+ * Function to pass to rn_walktree().
+ * Return non-zero error to abort walk.
+ */
+static int
+db_show_radix_node(rn, w)
+	struct radix_node *rn;
+	void *w;
+{
+	struct rtentry *rt = (struct rtentry *)rn;
+
+	db_printf("rtentry=%p", rt);
+
+	db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n",
+			  rt->rt_flags, rt->rt_refcnt,
+			  rt->rt_use, rt->rt_expire);
+
+	db_printf(" key="); db_print_sa(rt_key(rt));
+	db_printf(" mask="); db_print_sa(rt_mask(rt));
+	db_printf(" gw="); db_print_sa(rt->rt_gateway);
+
+	db_printf(" ifp=%p ", rt->rt_ifp);
+	if (rt->rt_ifp)
+		db_printf("(%s%d)",
+				  rt->rt_ifp->if_name,
+				  rt->rt_ifp->if_unit);
+	else
+		db_printf("(NULL)");
+
+	db_printf(" ifa=%p\n", rt->rt_ifa);
+	db_print_ifa(rt->rt_ifa);
+
+	db_printf(" genmask="); db_print_sa(rt->rt_genmask);
+
+	db_printf(" gwroute=%p llinfo=%p\n",
+			  rt->rt_gwroute, rt->rt_llinfo);
+	db_print_llinfo(rt->rt_llinfo);
+
+	return (0);
+}
+/*
+ * Function to print all the route trees.
+ * Use this from ddb:  "call db_show_arptab"
+ */
+int
+db_show_arptab()
+{
+	struct radix_node_head *rnh;
+	rnh = rt_tables[AF_INET];
+	db_printf("Route tree for AF_INET\n");
+	if (rnh == NULL) {
+		db_printf(" (not initialized)\n");
+		return (0);
+	}
+	rn_walktree(rnh, db_show_radix_node, NULL);
+	return (0);
+}
+#endif
+#endif /* INET */