635 lines
18 KiB
C
635 lines
18 KiB
C
/*
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* Copyright (c) 1982, 1986, 1988, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)if_ether.c 8.1 (Berkeley) 6/10/93
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* $Id: if_ether.c,v 1.6 1994/10/11 23:16:37 wollman Exp $
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*/
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/*
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* Ethernet address resolution protocol.
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* TODO:
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* add "inuse/lock" bit (or ref. count) along with valid bit
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <sys/kernel.h>
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#include <sys/errno.h>
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#include <sys/ioctl.h>
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#include <sys/syslog.h>
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#include <net/if.h>
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#include <net/if_dl.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_var.h>
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#include <netinet/ip.h>
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#include <netinet/if_ether.h>
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#define SIN(s) ((struct sockaddr_in *)s)
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#define SDL(s) ((struct sockaddr_dl *)s)
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#define SRP(s) ((struct sockaddr_inarp *)s)
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/*
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* ARP trailer negotiation. Trailer protocol is not IP specific,
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* but ARP request/response use IP addresses.
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*/
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#define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL
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/* timer values */
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int arpt_prune = (5*60*1); /* walk list every 5 minutes */
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int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */
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int arpt_down = 20; /* once declared down, don't send for 20 secs */
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#define rt_expire rt_rmx.rmx_expire
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static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *));
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static void arptfree __P((struct llinfo_arp *));
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static void arptimer __P((void *));
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static struct llinfo_arp *arplookup __P((u_long, int, int));
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static void in_arpinput __P((struct mbuf *));
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extern struct ifnet loif;
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struct llinfo_arp llinfo_arp = {&llinfo_arp, &llinfo_arp};
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struct ifqueue arpintrq = {0, 0, 0, 50};
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int arp_inuse, arp_allocated, arp_intimer;
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int arp_maxtries = 5;
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int useloopback = 1; /* use loopback interface for local traffic */
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int arpinit_done = 0;
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#ifdef ARP_PROXYALL
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int arp_proxyall = 1;
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#endif
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/*
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* Support: format an IP address. There should be a standard kernel routine
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* to do this.
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*/
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static char *
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arp_ntoa(struct in_addr *x)
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{
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static char buf[4*sizeof "123"];
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unsigned char *ucp = (unsigned char *)x;
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sprintf(buf, "%d.%d.%d.%d",
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ucp[0] & 0xff,
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ucp[1] & 0xff,
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ucp[2] & 0xff,
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ucp[3] & 0xff);
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return buf;
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}
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/*
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* Timeout routine. Age arp_tab entries periodically.
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*/
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/* ARGSUSED */
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static void
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arptimer(ignored_arg)
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void *ignored_arg;
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{
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int s = splnet();
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register struct llinfo_arp *la = llinfo_arp.la_next;
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timeout(arptimer, (caddr_t)0, arpt_prune * hz);
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while (la != &llinfo_arp) {
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register struct rtentry *rt = la->la_rt;
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la = la->la_next;
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if (rt->rt_expire && rt->rt_expire <= time.tv_sec)
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arptfree(la->la_prev); /* timer has expired, clear */
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}
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splx(s);
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}
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/*
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* Parallel to llc_rtrequest.
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*/
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void
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arp_rtrequest(req, rt, sa)
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int req;
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register struct rtentry *rt;
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struct sockaddr *sa;
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{
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register struct sockaddr *gate = rt->rt_gateway;
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register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo;
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static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK};
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if (!arpinit_done) {
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arpinit_done = 1;
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timeout(arptimer, (caddr_t)0, hz);
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}
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if (rt->rt_flags & RTF_GATEWAY)
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return;
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switch (req) {
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case RTM_ADD:
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/*
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* XXX: If this is a manually added route to interface
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* such as older version of routed or gated might provide,
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* restore cloning bit.
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*/
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if ((rt->rt_flags & RTF_HOST) == 0 &&
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SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff)
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rt->rt_flags |= RTF_CLONING;
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#if 0
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/*
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* Actually, all IP gateway routes should have the cloning
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* flag turned on. We can't do this yet because the expiration
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* stuff isn't working yet.
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*/
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if (rt->rt_flags & RTF_GATEWAY) {
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rt->rt_flags |= RTF_CLONING;
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}
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#endif
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if (rt->rt_flags & RTF_CLONING) {
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/*
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* Case 1: This route should come from a route to iface.
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*/
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rt_setgate(rt, rt_key(rt),
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(struct sockaddr *)&null_sdl);
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gate = rt->rt_gateway;
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SDL(gate)->sdl_type = rt->rt_ifp->if_type;
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SDL(gate)->sdl_index = rt->rt_ifp->if_index;
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rt->rt_expire = time.tv_sec;
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break;
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}
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/* Announce a new entry if requested. */
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if (rt->rt_flags & RTF_ANNOUNCE)
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arprequest((struct arpcom *)rt->rt_ifp,
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&SIN(rt_key(rt))->sin_addr.s_addr,
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&SIN(rt_key(rt))->sin_addr.s_addr,
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(u_char *)LLADDR(SDL(gate)));
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/*FALLTHROUGH*/
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case RTM_RESOLVE:
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if (gate->sa_family != AF_LINK ||
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gate->sa_len < sizeof(null_sdl)) {
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log(LOG_DEBUG, "arp_rtrequest: bad gateway value");
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break;
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}
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SDL(gate)->sdl_type = rt->rt_ifp->if_type;
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SDL(gate)->sdl_index = rt->rt_ifp->if_index;
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if (la != 0)
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break; /* This happens on a route change */
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/*
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* Case 2: This route may come from cloning, or a manual route
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* add with a LL address.
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*/
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R_Malloc(la, struct llinfo_arp *, sizeof(*la));
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rt->rt_llinfo = (caddr_t)la;
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if (la == 0) {
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log(LOG_DEBUG, "arp_rtrequest: malloc failed\n");
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break;
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}
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arp_inuse++, arp_allocated++;
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Bzero(la, sizeof(*la));
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la->la_rt = rt;
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rt->rt_flags |= RTF_LLINFO;
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insque(la, &llinfo_arp);
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if (SIN(rt_key(rt))->sin_addr.s_addr ==
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(IA_SIN(rt->rt_ifa))->sin_addr.s_addr) {
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/*
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* This test used to be
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* if (loif.if_flags & IFF_UP)
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* It allowed local traffic to be forced
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* through the hardware by configuring the loopback down.
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* However, it causes problems during network configuration
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* for boards that can't receive packets they send.
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* It is now necessary to clear "useloopback" and remove
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* the route to force traffic out to the hardware.
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*/
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rt->rt_expire = 0;
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Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr,
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LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6);
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if (useloopback)
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rt->rt_ifp = &loif;
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}
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break;
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case RTM_DELETE:
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if (la == 0)
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break;
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arp_inuse--;
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remque(la);
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rt->rt_llinfo = 0;
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rt->rt_flags &= ~RTF_LLINFO;
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if (la->la_hold)
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m_freem(la->la_hold);
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Free((caddr_t)la);
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}
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}
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/*
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* Broadcast an ARP packet, asking who has addr on interface ac.
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*/
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void
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arpwhohas(ac, addr)
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register struct arpcom *ac;
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register struct in_addr *addr;
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{
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arprequest(ac, &ac->ac_ipaddr.s_addr, &addr->s_addr, ac->ac_enaddr);
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}
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/*
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* Broadcast an ARP request. Caller specifies:
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* - arp header source ip address
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* - arp header target ip address
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* - arp header source ethernet address
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*/
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static void
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arprequest(ac, sip, tip, enaddr)
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register struct arpcom *ac;
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register u_long *sip, *tip;
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register u_char *enaddr;
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{
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register struct mbuf *m;
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register struct ether_header *eh;
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register struct ether_arp *ea;
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struct sockaddr sa;
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if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL)
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return;
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m->m_len = sizeof(*ea);
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m->m_pkthdr.len = sizeof(*ea);
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MH_ALIGN(m, sizeof(*ea));
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ea = mtod(m, struct ether_arp *);
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eh = (struct ether_header *)sa.sa_data;
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bzero((caddr_t)ea, sizeof (*ea));
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bcopy((caddr_t)etherbroadcastaddr, (caddr_t)eh->ether_dhost,
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sizeof(eh->ether_dhost));
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eh->ether_type = ETHERTYPE_ARP; /* if_output will swap */
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ea->arp_hrd = htons(ARPHRD_ETHER);
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ea->arp_pro = htons(ETHERTYPE_IP);
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ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */
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ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */
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ea->arp_op = htons(ARPOP_REQUEST);
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bcopy((caddr_t)enaddr, (caddr_t)ea->arp_sha, sizeof(ea->arp_sha));
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bcopy((caddr_t)sip, (caddr_t)ea->arp_spa, sizeof(ea->arp_spa));
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bcopy((caddr_t)tip, (caddr_t)ea->arp_tpa, sizeof(ea->arp_tpa));
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sa.sa_family = AF_UNSPEC;
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sa.sa_len = sizeof(sa);
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(*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0);
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}
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/*
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* Resolve an IP address into an ethernet address. If success,
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* desten is filled in. If there is no entry in arptab,
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* set one up and broadcast a request for the IP address.
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* Hold onto this mbuf and resend it once the address
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* is finally resolved. A return value of 1 indicates
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* that desten has been filled in and the packet should be sent
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* normally; a 0 return indicates that the packet has been
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* taken over here, either now or for later transmission.
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*/
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int
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arpresolve(ac, rt, m, dst, desten, rt0)
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register struct arpcom *ac;
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register struct rtentry *rt;
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struct mbuf *m;
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register struct sockaddr *dst;
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register u_char *desten;
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struct rtentry *rt0;
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{
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register struct llinfo_arp *la;
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struct sockaddr_dl *sdl;
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if (m->m_flags & M_BCAST) { /* broadcast */
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bcopy((caddr_t)etherbroadcastaddr, (caddr_t)desten,
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sizeof(etherbroadcastaddr));
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return (1);
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}
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if (m->m_flags & M_MCAST) { /* multicast */
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ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten);
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return(1);
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}
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if (rt)
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la = (struct llinfo_arp *)rt->rt_llinfo;
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else {
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la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0);
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if (la)
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rt = la->la_rt;
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}
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if (la == 0 || rt == 0) {
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log(LOG_DEBUG, "arpresolve: can't allocate llinfo");
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m_freem(m);
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return (0);
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}
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sdl = SDL(rt->rt_gateway);
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/*
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* Check the address family and length is valid, the address
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* is resolved; otherwise, try to resolve.
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*/
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if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) &&
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sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) {
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bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
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return 1;
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}
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/*
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* There is an arptab entry, but no ethernet address
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* response yet. Replace the held mbuf with this
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* latest one.
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*/
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if (la->la_hold)
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m_freem(la->la_hold);
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la->la_hold = m;
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if (rt->rt_expire) {
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rt->rt_flags &= ~RTF_REJECT;
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if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) {
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rt->rt_expire = time.tv_sec;
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if (la->la_asked++ < arp_maxtries)
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arpwhohas(ac, &(SIN(dst)->sin_addr));
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else {
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rt->rt_flags |= RTF_REJECT;
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rt->rt_expire += arpt_down;
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la->la_asked = 0;
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}
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}
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}
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return (0);
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}
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/*
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* Common length and type checks are done here,
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* then the protocol-specific routine is called.
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*/
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void
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arpintr()
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{
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register struct mbuf *m;
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register struct arphdr *ar;
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int s;
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while (arpintrq.ifq_head) {
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s = splimp();
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IF_DEQUEUE(&arpintrq, m);
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splx(s);
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if (m == 0 || (m->m_flags & M_PKTHDR) == 0)
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panic("arpintr");
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if (m->m_len >= sizeof(struct arphdr) &&
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(ar = mtod(m, struct arphdr *)) &&
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ntohs(ar->ar_hrd) == ARPHRD_ETHER &&
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m->m_len >=
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sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln)
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switch (ntohs(ar->ar_pro)) {
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case ETHERTYPE_IP:
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case ETHERTYPE_IPTRAILERS:
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in_arpinput(m);
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continue;
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}
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m_freem(m);
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}
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}
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/*
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* ARP for Internet protocols on 10 Mb/s Ethernet.
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* Algorithm is that given in RFC 826.
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* In addition, a sanity check is performed on the sender
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* protocol address, to catch impersonators.
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* We no longer handle negotiations for use of trailer protocol:
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* Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent
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* along with IP replies if we wanted trailers sent to us,
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* and also sent them in response to IP replies.
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* This allowed either end to announce the desire to receive
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* trailer packets.
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* We no longer reply to requests for ETHERTYPE_TRAIL protocol either,
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* but formerly didn't normally send requests.
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*/
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static void
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in_arpinput(m)
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struct mbuf *m;
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{
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register struct ether_arp *ea;
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register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif;
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struct ether_header *eh;
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register struct llinfo_arp *la = 0;
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register struct rtentry *rt;
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struct in_ifaddr *ia, *maybe_ia = 0;
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struct sockaddr_dl *sdl;
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struct sockaddr sa;
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struct in_addr isaddr, itaddr, myaddr;
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int op;
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ea = mtod(m, struct ether_arp *);
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op = ntohs(ea->arp_op);
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bcopy((caddr_t)ea->arp_spa, (caddr_t)&isaddr, sizeof (isaddr));
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bcopy((caddr_t)ea->arp_tpa, (caddr_t)&itaddr, sizeof (itaddr));
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for (ia = in_ifaddr; ia; ia = ia->ia_next)
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if (ia->ia_ifp == &ac->ac_if) {
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maybe_ia = ia;
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if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) ||
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(isaddr.s_addr == ia->ia_addr.sin_addr.s_addr))
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break;
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}
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if (maybe_ia == 0)
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goto out;
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myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr;
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if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr,
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sizeof (ea->arp_sha)))
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goto out; /* it's from me, ignore it. */
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if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr,
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sizeof (ea->arp_sha))) {
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log(LOG_ERR,
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"arp: ether address is broadcast for IP address %s!\n",
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arp_ntoa(&isaddr));
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goto out;
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}
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if (isaddr.s_addr == myaddr.s_addr) {
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log(LOG_ERR,
|
|
"duplicate IP address %s! sent from ethernet address: %s\n",
|
|
arp_ntoa(&isaddr), 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 %s by %s\n",
|
|
arp_ntoa(&isaddr), 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 == 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);
|
|
#ifdef DEBUG_PROXY
|
|
printf("arp: proxying for %s\n",
|
|
arp_ntoa(&itaddr));
|
|
#endif
|
|
#else
|
|
goto out;
|
|
#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));
|
|
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 = 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_long addr;
|
|
int create, proxy;
|
|
{
|
|
register struct rtentry *rt;
|
|
static struct sockaddr_inarp sin = {sizeof(sin), AF_INET };
|
|
const char *why = 0;
|
|
|
|
sin.sin_addr.s_addr = addr;
|
|
sin.sin_other = proxy ? SIN_PROXY : 0;
|
|
rt = rtalloc1((struct sockaddr *)&sin, create);
|
|
if (rt == 0)
|
|
return (0);
|
|
rt->rt_refcnt--;
|
|
|
|
if(rt->rt_flags & RTF_GATEWAY)
|
|
why = "host is not on local network";
|
|
else if((rt->rt_flags & RTF_LLINFO) == 0)
|
|
why = "could not allocate llinfo";
|
|
else if(rt->rt_gateway->sa_family != AF_LINK)
|
|
why = "gateway route is not ours";
|
|
|
|
if(why && create) {
|
|
log(LOG_DEBUG, "arplookup %s failed: %s\n",
|
|
arp_ntoa(&sin.sin_addr), why);
|
|
return 0;
|
|
} else if(why) {
|
|
return 0;
|
|
}
|
|
return ((struct llinfo_arp *)rt->rt_llinfo);
|
|
}
|
|
|
|
int
|
|
arpioctl(cmd, data)
|
|
int cmd;
|
|
caddr_t data;
|
|
{
|
|
return (EOPNOTSUPP);
|
|
}
|