/* $NetBSD: if_arp.c,v 1.128 2007/09/02 19:42:22 dyoung Exp $ */ /*- * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Public Access Networks Corporation ("Panix"). It was developed under * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. * * 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 NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * 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. 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 8.2 (Berkeley) 9/26/94 */ /* * Ethernet address resolution protocol. * TODO: * add "inuse/lock" bit (or ref. count) along with valid bit */ #include __KERNEL_RCSID(0, "$NetBSD: if_arp.c,v 1.128 2007/09/02 19:42:22 dyoung Exp $"); #include "opt_ddb.h" #include "opt_inet.h" #ifdef INET #include "bridge.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "arc.h" #if NARC > 0 #include #endif #include "fddi.h" #if NFDDI > 0 #include #endif #include "token.h" #include "carp.h" #if NCARP > 0 #include #endif #define SIN(s) ((struct sockaddr_in *)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 */ int arpt_refresh = (5*60); /* time left before refreshing */ #define rt_expire rt_rmx.rmx_expire #define rt_pksent rt_rmx.rmx_pksent static struct sockaddr *arp_setgate(struct rtentry *, struct sockaddr *, const struct sockaddr *); static void arptfree(struct llinfo_arp *); static void arptimer(void *); static struct llinfo_arp *arplookup1(struct mbuf *, const struct in_addr *, int, int, struct rtentry *); static struct llinfo_arp *arplookup(struct mbuf *, const struct in_addr *, int, int); static void in_arpinput(struct mbuf *); LIST_HEAD(, llinfo_arp) llinfo_arp; struct ifqueue arpintrq = { .ifq_head = NULL, .ifq_tail = NULL, .ifq_len = 0, .ifq_maxlen = 50, .ifq_drops = 0, }; int arp_inuse, arp_allocated, arp_intimer; int arp_maxtries = 5; int useloopback = 1; /* use loopback interface for local traffic */ int arpinit_done = 0; struct arpstat arpstat; struct callout arptimer_ch; /* revarp state */ struct in_addr myip, srv_ip; int myip_initialized = 0; int revarp_in_progress = 0; struct ifnet *myip_ifp = NULL; #ifdef DDB static void db_print_sa(const struct sockaddr *); static void db_print_ifa(struct ifaddr *); static void db_print_llinfo(void *); static int db_show_rtentry(struct rtentry *, void *); #endif /* * this should be elsewhere. */ static char * lla_snprintf(u_int8_t *, int); static char * lla_snprintf(u_int8_t *adrp, int len) { #define NUMBUFS 3 static char buf[NUMBUFS][16*3]; static int bnum = 0; int i; char *p; p = buf[bnum]; *p++ = hexdigits[(*adrp)>>4]; *p++ = hexdigits[(*adrp++)&0xf]; for (i=1; i>4]; *p++ = hexdigits[(*adrp++)&0xf]; } *p = 0; p = buf[bnum]; bnum = (bnum + 1) % NUMBUFS; return p; } DOMAIN_DEFINE(arpdomain); /* forward declare and add to link set */ const struct protosw arpsw[] = { { 0, &arpdomain, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, arp_drain, } }; struct domain arpdomain = { .dom_family = PF_ARP, .dom_name = "arp", .dom_protosw = arpsw, .dom_protoswNPROTOSW = &arpsw[sizeof(arpsw)/sizeof(arpsw[0])], }; /* * ARP table locking. * * to prevent lossage vs. the arp_drain routine (which may be called at * any time, including in a device driver context), we do two things: * * 1) manipulation of la->la_hold is done at splnet() (for all of * about two instructions). * * 2) manipulation of the arp table's linked list is done under the * protection of the ARP_LOCK; if arp_drain() or arptimer is called * while the arp table is locked, we punt and try again later. */ static int arp_locked; static inline int arp_lock_try(int); static inline void arp_unlock(void); static inline int arp_lock_try(int recurse) { int s; /* * Use splvm() -- we're blocking things that would cause * mbuf allocation. */ s = splvm(); if (!recurse && arp_locked) { splx(s); return (0); } arp_locked++; splx(s); return (1); } static inline void arp_unlock(void) { int s; s = splvm(); arp_locked--; splx(s); } #ifdef DIAGNOSTIC #define ARP_LOCK(recurse) \ do { \ if (arp_lock_try(recurse) == 0) { \ printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \ panic("arp_lock"); \ } \ } while (/*CONSTCOND*/ 0) #define ARP_LOCK_CHECK() \ do { \ if (arp_locked == 0) { \ printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \ panic("arp lock check"); \ } \ } while (/*CONSTCOND*/ 0) #else #define ARP_LOCK(x) (void) arp_lock_try(x) #define ARP_LOCK_CHECK() /* nothing */ #endif #define ARP_UNLOCK() arp_unlock() /* * ARP protocol drain routine. Called when memory is in short supply. * Called at splvm(); */ void arp_drain(void) { struct llinfo_arp *la, *nla; int count = 0; struct mbuf *mold; if (arp_lock_try(0) == 0) { printf("arp_drain: locked; punting\n"); return; } for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) { nla = LIST_NEXT(la, la_list); mold = la->la_hold; la->la_hold = 0; if (mold) { m_freem(mold); count++; } } ARP_UNLOCK(); arpstat.as_dfrdropped += count; } /* * Timeout routine. Age arp_tab entries periodically. */ /* ARGSUSED */ static void arptimer(void *arg) { int s; struct llinfo_arp *la, *nla; s = splsoftnet(); if (arp_lock_try(0) == 0) { /* get it later.. */ splx(s); return; } callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); for (la = LIST_FIRST(&llinfo_arp); la != 0; la = nla) { struct rtentry *rt = la->la_rt; nla = LIST_NEXT(la, la_list); if (rt->rt_expire == 0) continue; if ((rt->rt_expire - time_second) < arpt_refresh && rt->rt_pksent > (time_second - arpt_keep)) { /* * If the entry has been used during since last * refresh, try to renew it before deleting. */ arprequest(rt->rt_ifp, &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, &satocsin(rt_getkey(rt))->sin_addr, CLLADDR(rt->rt_ifp->if_sadl)); } else if (rt->rt_expire <= time_second) arptfree(la); /* timer has expired; clear */ } ARP_UNLOCK(); splx(s); } /* * We set the gateway for RTF_CLONING routes to a "prototype" * link-layer sockaddr whose interface type (if_type) and interface * index (if_index) fields are prepared. */ static struct sockaddr * arp_setgate(struct rtentry *rt, struct sockaddr *gate, const struct sockaddr *netmask) { const struct ifnet *ifp = rt->rt_ifp; uint8_t namelen = strlen(ifp->if_xname); uint8_t addrlen = ifp->if_addrlen; /* * 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 && netmask != NULL && satocsin(netmask)->sin_addr.s_addr != 0xffffffff) rt->rt_flags |= RTF_CLONING; if (rt->rt_flags & RTF_CLONING) { union { struct sockaddr sa; struct sockaddr_storage ss; struct sockaddr_dl sdl; } u; /* * Case 1: This route should come from a route to iface. */ sockaddr_dl_init(&u.sdl, sizeof(u.ss), ifp->if_index, ifp->if_type, NULL, namelen, NULL, addrlen); rt_setgate(rt, &u.sa); gate = rt->rt_gateway; } return gate; } /* * Parallel to llc_rtrequest. */ void arp_rtrequest(int req, struct rtentry *rt, struct rt_addrinfo *info) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; size_t allocsize; struct mbuf *mold; int s; struct in_ifaddr *ia; struct ifaddr *ifa; struct ifnet *ifp = rt->rt_ifp; uint8_t namelen = strlen(ifp->if_xname); uint8_t addrlen = ifp->if_addrlen; if (!arpinit_done) { arpinit_done = 1; /* * We generate expiration times from time_second * so avoid accidentally creating permanent routes. */ if (time_second == 0) { #ifdef __HAVE_TIMECOUNTER struct timespec ts; ts.tv_sec = 1; ts.tv_nsec = 0; tc_setclock(&ts); #else /* !__HAVE_TIMECOUNTER */ time.tv_sec++; #endif /* !__HAVE_TIMECOUNTER */ } callout_init(&arptimer_ch, 0); callout_reset(&arptimer_ch, hz, arptimer, NULL); } if ((rt->rt_flags & RTF_GATEWAY) != 0) { if (req != RTM_ADD) return; /* * linklayers with particular link MTU limitation. */ switch(ifp->if_type) { #if NFDDI > 0 case IFT_FDDI: if (ifp->if_mtu > FDDIIPMTU) rt->rt_rmx.rmx_mtu = FDDIIPMTU; break; #endif #if NARC > 0 case IFT_ARCNET: { int arcipifmtu; if (ifp->if_flags & IFF_LINK0) arcipifmtu = arc_ipmtu; else arcipifmtu = ARCMTU; if (ifp->if_mtu > arcipifmtu) rt->rt_rmx.rmx_mtu = arcipifmtu; break; } #endif } return; } ARP_LOCK(1); /* we may already be locked here. */ switch (req) { case RTM_SETGATE: gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); break; case RTM_ADD: gate = arp_setgate(rt, gate, info->rti_info[RTAX_NETMASK]); if (rt->rt_flags & RTF_CLONING) { /* * 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_second; /* * linklayers with particular link MTU limitation. */ switch (ifp->if_type) { #if NFDDI > 0 case IFT_FDDI: if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && (rt->rt_rmx.rmx_mtu > FDDIIPMTU || (rt->rt_rmx.rmx_mtu == 0 && ifp->if_mtu > FDDIIPMTU))) rt->rt_rmx.rmx_mtu = FDDIIPMTU; break; #endif #if NARC > 0 case IFT_ARCNET: { int arcipifmtu; if (ifp->if_flags & IFF_LINK0) arcipifmtu = arc_ipmtu; else arcipifmtu = ARCMTU; if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0 && (rt->rt_rmx.rmx_mtu > arcipifmtu || (rt->rt_rmx.rmx_mtu == 0 && ifp->if_mtu > arcipifmtu))) rt->rt_rmx.rmx_mtu = arcipifmtu; break; } #endif } break; } /* Announce a new entry if requested. */ if (rt->rt_flags & RTF_ANNOUNCE) arprequest(ifp, &satocsin(rt_getkey(rt))->sin_addr, &satocsin(rt_getkey(rt))->sin_addr, CLLADDR(satocsdl(gate))); /*FALLTHROUGH*/ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sockaddr_dl_measure(namelen, addrlen)) { log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); break; } satosdl(gate)->sdl_type = ifp->if_type; satosdl(gate)->sdl_index = 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. */ switch (satocsdl(gate)->sdl_type) { #if NTOKEN > 0 case IFT_ISO88025: allocsize = sizeof(*la) + sizeof(struct token_rif); break; #endif /* NTOKEN > 0 */ default: allocsize = sizeof(*la); } R_Malloc(la, struct llinfo_arp *, allocsize); rt->rt_llinfo = (void *)la; if (la == 0) { log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); break; } arp_inuse++, arp_allocated++; Bzero(la, allocsize); la->la_rt = rt; rt->rt_flags |= RTF_LLINFO; LIST_INSERT_HEAD(&llinfo_arp, la, la_list); INADDR_TO_IA(satocsin(rt_getkey(rt))->sin_addr, ia); while (ia && ia->ia_ifp != ifp) NEXT_IA_WITH_SAME_ADDR(ia); if (ia) { /* * This test used to be * if (lo0ifp->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. * * In 4.4BSD, the above "if" statement checked * rt->rt_ifa against rt_getkey(rt). It was changed * to the current form so that we can provide a * better support for multiple IPv4 addresses on a * interface. */ rt->rt_expire = 0; (void)sockaddr_dl_setaddr(satosdl(gate), gate->sa_len, CLLADDR(ifp->if_sadl), ifp->if_addrlen); if (useloopback) ifp = rt->rt_ifp = lo0ifp; /* * make sure to set rt->rt_ifa to the interface * address we are using, otherwise we will have trouble * with source address selection. */ ifa = &ia->ia_ifa; if (ifa != rt->rt_ifa) rt_replace_ifa(rt, ifa); } break; case RTM_DELETE: if (la == 0) break; arp_inuse--; LIST_REMOVE(la, la_list); rt->rt_llinfo = 0; rt->rt_flags &= ~RTF_LLINFO; s = splnet(); mold = la->la_hold; la->la_hold = 0; splx(s); if (mold) m_freem(mold); Free((void *)la); } ARP_UNLOCK(); } /* * Broadcast an ARP request. Caller specifies: * - arp header source ip address * - arp header target ip address * - arp header source ethernet address */ void arprequest(struct ifnet *ifp, const struct in_addr *sip, const struct in_addr *tip, const u_int8_t *enaddr) { struct mbuf *m; struct arphdr *ah; struct sockaddr sa; if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) return; MCLAIM(m, &arpdomain.dom_mowner); switch (ifp->if_type) { case IFT_IEEE1394: m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + ifp->if_addrlen; break; default: m->m_len = sizeof(*ah) + 2 * sizeof(struct in_addr) + 2 * ifp->if_addrlen; break; } m->m_pkthdr.len = m->m_len; MH_ALIGN(m, m->m_len); ah = mtod(m, struct arphdr *); bzero((void *)ah, m->m_len); switch (ifp->if_type) { case IFT_IEEE1394: /* RFC2734 */ /* fill it now for ar_tpa computation */ ah->ar_hrd = htons(ARPHRD_IEEE1394); break; default: /* ifp->if_output will fill ar_hrd */ break; } ah->ar_pro = htons(ETHERTYPE_IP); ah->ar_hln = ifp->if_addrlen; /* hardware address length */ ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ ah->ar_op = htons(ARPOP_REQUEST); memcpy(ar_sha(ah), enaddr, ah->ar_hln); memcpy(ar_spa(ah), sip, ah->ar_pln); memcpy(ar_tpa(ah), tip, ah->ar_pln); sa.sa_family = AF_ARP; sa.sa_len = 2; m->m_flags |= M_BCAST; arpstat.as_sndtotal++; arpstat.as_sndrequest++; (*ifp->if_output)(ifp, m, &sa, NULL); } /* * 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(struct ifnet *ifp, struct rtentry *rt, struct mbuf *m, const struct sockaddr *dst, u_char *desten) { struct llinfo_arp *la; const struct sockaddr_dl *sdl; struct mbuf *mold; int s; if ((la = arplookup1(m, &satocsin(dst)->sin_addr, 1, 0, rt)) != NULL) rt = la->la_rt; if (la == 0 || rt == 0) { arpstat.as_allocfail++; log(LOG_DEBUG, "arpresolve: can't allocate llinfo on %s for %s\n", ifp->if_xname, in_fmtaddr(satocsin(dst)->sin_addr)); m_freem(m); return (0); } sdl = satocsdl(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_second) && sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { bcopy(CLLADDR(sdl), desten, min(sdl->sdl_alen, ifp->if_addrlen)); rt->rt_pksent = time_second; /* Time for last pkt sent */ return 1; } /* * There is an arptab entry, but no ethernet address * response yet. Replace the held mbuf with this * latest one. */ arpstat.as_dfrtotal++; s = splnet(); mold = la->la_hold; la->la_hold = m; splx(s); if (mold) { arpstat.as_dfrdropped++; m_freem(mold); } /* * 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_second; } #endif if (rt->rt_expire) { rt->rt_flags &= ~RTF_REJECT; if (la->la_asked == 0 || rt->rt_expire != time_second) { rt->rt_expire = time_second; if (la->la_asked++ < arp_maxtries) arprequest(ifp, &satocsin(rt->rt_ifa->ifa_addr)->sin_addr, &satocsin(dst)->sin_addr, #if NCARP > 0 (rt->rt_ifp->if_type == IFT_CARP) ? CLLADDR(rt->rt_ifp->if_sadl): #endif CLLADDR(ifp->if_sadl)); 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(void) { struct mbuf *m; struct arphdr *ar; int s; int arplen; while (arpintrq.ifq_head) { s = splnet(); IF_DEQUEUE(&arpintrq, m); splx(s); if (m == 0 || (m->m_flags & M_PKTHDR) == 0) panic("arpintr"); MCLAIM(m, &arpdomain.dom_mowner); arpstat.as_rcvtotal++; /* * First, make sure we have at least struct arphdr. */ if (m->m_len < sizeof(struct arphdr) || (ar = mtod(m, struct arphdr *)) == NULL) goto badlen; switch (m->m_pkthdr.rcvif->if_type) { case IFT_IEEE1394: arplen = sizeof(struct arphdr) + ar->ar_hln + 2 * ar->ar_pln; break; default: arplen = sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln; break; } if (/* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ m->m_len >= arplen) switch (ntohs(ar->ar_pro)) { case ETHERTYPE_IP: case ETHERTYPE_IPTRAILERS: in_arpinput(m); continue; default: arpstat.as_rcvbadproto++; } else { badlen: arpstat.as_rcvbadlen++; } 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(struct mbuf *m) { struct arphdr *ah; struct ifnet *ifp = m->m_pkthdr.rcvif; struct llinfo_arp *la = 0; struct rtentry *rt; struct in_ifaddr *ia; #if NBRIDGE > 0 struct in_ifaddr *bridge_ia = NULL; #endif #if NCARP > 0 u_int32_t count = 0, index = 0; #endif struct sockaddr_dl *sdl; struct sockaddr sa; struct in_addr isaddr, itaddr, myaddr; int op; struct mbuf *mold; void *tha; int s; if (__predict_false(m_makewritable(&m, 0, m->m_pkthdr.len, M_DONTWAIT))) goto out; ah = mtod(m, struct arphdr *); op = ntohs(ah->ar_op); /* * Fix up ah->ar_hrd if necessary, before using ar_tha() or * ar_tpa(). */ switch (ifp->if_type) { case IFT_IEEE1394: if (ntohs(ah->ar_hrd) == ARPHRD_IEEE1394) ; else { /* XXX this is to make sure we compute ar_tha right */ /* XXX check ar_hrd more strictly? */ ah->ar_hrd = htons(ARPHRD_IEEE1394); } break; default: /* XXX check ar_hrd? */ break; } memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); if (m->m_flags & (M_BCAST|M_MCAST)) arpstat.as_rcvmcast++; /* * If the target IP address is zero, ignore the packet. * This prevents the code below from tring to answer * when we are using IP address zero (booting). */ if (in_nullhost(itaddr)) { arpstat.as_rcvzerotpa++; goto out; } /* * If the source IP address is zero, this is most likely a * confused host trying to use IP address zero. (Windoze?) * XXX: Should we bother trying to reply to these? */ if (in_nullhost(isaddr)) { arpstat.as_rcvzerospa++; goto out; } /* * Search for a matching interface address * or any address on the interface to use * as a dummy address in the rest of this function */ INADDR_TO_IA(itaddr, ia); while (ia != NULL) { #if NCARP > 0 if (ia->ia_ifp->if_type == IFT_CARP && ((ia->ia_ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING))) { index++; if (ia->ia_ifp == m->m_pkthdr.rcvif && carp_iamatch(ia, ar_sha(ah), &count, index)) { break; } } else #endif if (ia->ia_ifp == m->m_pkthdr.rcvif) break; #if NBRIDGE > 0 /* * If the interface we received the packet on * is part of a bridge, check to see if we need * to "bridge" the packet to ourselves at this * layer. Note we still prefer a perfect match, * but allow this weaker match if necessary. */ if (m->m_pkthdr.rcvif->if_bridge != NULL && m->m_pkthdr.rcvif->if_bridge == ia->ia_ifp->if_bridge) bridge_ia = ia; #endif /* NBRIDGE > 0 */ NEXT_IA_WITH_SAME_ADDR(ia); } #if NBRIDGE > 0 if (ia == NULL && bridge_ia != NULL) { ia = bridge_ia; ifp = bridge_ia->ia_ifp; } #endif if (ia == NULL) { INADDR_TO_IA(isaddr, ia); while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) NEXT_IA_WITH_SAME_ADDR(ia); if (ia == NULL) { IFP_TO_IA(ifp, ia); if (ia == NULL) { arpstat.as_rcvnoint++; goto out; } } } myaddr = ia->ia_addr.sin_addr; /* XXX checks for bridge case? */ if (!memcmp(ar_sha(ah), CLLADDR(ifp->if_sadl), ifp->if_addrlen)) { arpstat.as_rcvlocalsha++; goto out; /* it's from me, ignore it. */ } /* XXX checks for bridge case? */ if (!memcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { arpstat.as_rcvbcastsha++; log(LOG_ERR, "%s: arp: link address is broadcast for IP address %s!\n", ifp->if_xname, in_fmtaddr(isaddr)); goto out; } if (in_hosteq(isaddr, myaddr)) { arpstat.as_rcvlocalspa++; log(LOG_ERR, "duplicate IP address %s sent from link address %s\n", in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); itaddr = myaddr; goto reply; } la = arplookup(m, &isaddr, in_hosteq(itaddr, myaddr), 0); if (la && (rt = la->la_rt) && (sdl = satosdl(rt->rt_gateway))) { if (sdl->sdl_alen && memcmp(ar_sha(ah), CLLADDR(sdl), sdl->sdl_alen)) { if (rt->rt_flags & RTF_STATIC) { arpstat.as_rcvoverperm++; log(LOG_INFO, "%s tried to overwrite permanent arp info" " for %s\n", lla_snprintf(ar_sha(ah), ah->ar_hln), in_fmtaddr(isaddr)); goto out; } else if (rt->rt_ifp != ifp) { arpstat.as_rcvoverint++; log(LOG_INFO, "%s on %s tried to overwrite " "arp info for %s on %s\n", lla_snprintf(ar_sha(ah), ah->ar_hln), ifp->if_xname, in_fmtaddr(isaddr), rt->rt_ifp->if_xname); goto out; } else { arpstat.as_rcvover++; log(LOG_INFO, "arp info overwritten for %s by %s\n", in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); } } /* * sanity check for the address length. * XXX this does not work for protocols with variable address * length. -is */ if (sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { arpstat.as_rcvlenchg++; log(LOG_WARNING, "arp from %s: new addr len %d, was %d", in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); } if (ifp->if_addrlen != ah->ar_hln) { arpstat.as_rcvbadlen++; log(LOG_WARNING, "arp from %s: addr len: new %d, i/f %d (ignored)", in_fmtaddr(isaddr), ah->ar_hln, ifp->if_addrlen); goto reply; } #if NTOKEN > 0 /* * XXX uses m_data and assumes the complete answer including * XXX token-ring headers is in the same buf */ if (ifp->if_type == IFT_ISO88025) { struct token_header *trh; trh = (struct token_header *)M_TRHSTART(m); if (trh->token_shost[0] & TOKEN_RI_PRESENT) { struct token_rif *rif; size_t riflen; rif = TOKEN_RIF(trh); riflen = (ntohs(rif->tr_rcf) & TOKEN_RCF_LEN_MASK) >> 8; if (riflen > 2 && riflen < sizeof(struct token_rif) && (riflen & 1) == 0) { rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); bcopy(rif, TOKEN_RIF(la), riflen); } } } #endif /* NTOKEN > 0 */ (void)sockaddr_dl_setaddr(sdl, sdl->sdl_len, ar_sha(ah), ah->ar_hln); if (rt->rt_expire) rt->rt_expire = time_second + arpt_keep; rt->rt_flags &= ~RTF_REJECT; la->la_asked = 0; s = splnet(); mold = la->la_hold; la->la_hold = 0; splx(s); if (mold) { arpstat.as_dfrsent++; (*ifp->if_output)(ifp, mold, rt_getkey(rt), rt); } } reply: if (op != ARPOP_REQUEST) { if (op == ARPOP_REPLY) arpstat.as_rcvreply++; out: m_freem(m); return; } arpstat.as_rcvrequest++; if (in_hosteq(itaddr, myaddr)) { /* I am the target */ tha = ar_tha(ah); if (tha) memcpy(tha, ar_sha(ah), ah->ar_hln); memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); } else { la = arplookup(m, &itaddr, 0, SIN_PROXY); if (la == 0) goto out; rt = la->la_rt; if (rt->rt_ifp->if_type == IFT_CARP && m->m_pkthdr.rcvif->if_type != IFT_CARP) goto out; tha = ar_tha(ah); if (tha) memcpy(tha, ar_sha(ah), ah->ar_hln); sdl = satosdl(rt->rt_gateway); memcpy(ar_sha(ah), CLLADDR(sdl), ah->ar_hln); } memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); memcpy(ar_spa(ah), &itaddr, ah->ar_pln); ah->ar_op = htons(ARPOP_REPLY); ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ switch (ifp->if_type) { case IFT_IEEE1394: /* * ieee1394 arp reply is broadcast */ m->m_flags &= ~M_MCAST; m->m_flags |= M_BCAST; m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + ah->ar_hln; break; default: m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); break; } m->m_pkthdr.len = m->m_len; sa.sa_family = AF_ARP; sa.sa_len = 2; arpstat.as_sndtotal++; arpstat.as_sndreply++; (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); return; } /* * Free an arp entry. */ static void arptfree(struct llinfo_arp *la) { struct rtentry *rt = la->la_rt; struct sockaddr_dl *sdl; ARP_LOCK_CHECK(); if (rt == 0) panic("arptfree"); if (rt->rt_refcnt > 0 && (sdl = satosdl(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_getkey(rt), NULL, rt_mask(rt), 0, NULL); } static struct llinfo_arp * arplookup(struct mbuf *m, const struct in_addr *addr, int create, int proxy) { return arplookup1(m, addr, create, proxy, NULL); } /* * Lookup or enter a new address in arptab. */ static struct llinfo_arp * arplookup1(struct mbuf *m, const struct in_addr *addr, int create, int proxy, struct rtentry *rt0) { struct arphdr *ah; struct ifnet *ifp = m->m_pkthdr.rcvif; struct rtentry *rt; static struct sockaddr_inarp sin; const char *why = 0; ah = mtod(m, struct arphdr *); if (rt0 == NULL) { sin.sin_len = sizeof(sin); sin.sin_family = AF_INET; sin.sin_addr = *addr; sin.sin_other = proxy ? SIN_PROXY : 0; rt = rtalloc1(sintosa(&sin), create); if (rt == NULL) return (NULL); rt->rt_refcnt--; } else rt = rt0; #define IS_LLINFO(__rt) \ (((__rt)->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) == RTF_LLINFO && \ (__rt)->rt_gateway->sa_family == AF_LINK) if (IS_LLINFO(rt)) return ((struct llinfo_arp *)rt->rt_llinfo); if (create) { if (rt->rt_flags & RTF_GATEWAY) why = "host is not on local network"; else if ((rt->rt_flags & RTF_LLINFO) == 0) { arpstat.as_allocfail++; why = "could not allocate llinfo"; } else why = "gateway route is not ours"; log(LOG_DEBUG, "arplookup: unable to enter address" " for %s@%s on %s (%s)\n", in_fmtaddr(*addr), lla_snprintf(ar_sha(ah), ah->ar_hln), (ifp) ? ifp->if_xname : 0, why); if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0); } } return (0); } int arpioctl(u_long cmd, void *data) { return (EOPNOTSUPP); } void arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) { struct in_addr *ip; /* * Warn the user if another station has this IP address, * but only if the interface IP address is not zero. */ ip = &IA_SIN(ifa)->sin_addr; if (!in_nullhost(*ip)) arprequest(ifp, ip, ip, CLLADDR(ifp->if_sadl)); 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(struct mbuf *m) { struct arphdr *ar; if (m->m_len < sizeof(struct arphdr)) goto out; ar = mtod(m, struct arphdr *); #if 0 /* XXX I don't think we need this... and it will prevent other LL */ if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) goto out; #endif 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(struct mbuf *m) { struct ifnet *ifp; struct arphdr *ah; void *tha; int op; ah = mtod(m, struct arphdr *); op = ntohs(ah->ar_op); switch (m->m_pkthdr.rcvif->if_type) { case IFT_IEEE1394: /* ARP without target hardware address is not supported */ goto out; default: break; } 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; tha = ar_tha(ah); KASSERT(tha); if (bcmp(tha, CLLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) goto out; memcpy(&srv_ip, ar_spa(ah), sizeof(srv_ip)); memcpy(&myip, ar_tpa(ah), sizeof(myip)); myip_initialized = 1; wake: /* Do wakeup every time in case it was missed. */ wakeup((void *)&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(struct ifnet *ifp) { struct sockaddr sa; struct mbuf *m; struct arphdr *ah; void *tha; if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) return; MCLAIM(m, &arpdomain.dom_mowner); m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 2*ifp->if_addrlen; m->m_pkthdr.len = m->m_len; MH_ALIGN(m, m->m_len); ah = mtod(m, struct arphdr *); bzero((void *)ah, m->m_len); ah->ar_pro = htons(ETHERTYPE_IP); ah->ar_hln = ifp->if_addrlen; /* hardware address length */ ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ ah->ar_op = htons(ARPOP_REVREQUEST); memcpy(ar_sha(ah), CLLADDR(ifp->if_sadl), ah->ar_hln); tha = ar_tha(ah); KASSERT(tha); bcopy(CLLADDR(ifp->if_sadl), tha, ah->ar_hln); sa.sa_family = AF_ARP; sa.sa_len = 2; m->m_flags |= M_BCAST; (*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(struct ifnet *ifp, struct in_addr *serv_in, struct in_addr *clnt_in) { int result, count = 20; myip_initialized = 0; myip_ifp = ifp; revarp_in_progress = 1; while (count--) { revarprequest(ifp); result = tsleep((void *)&myip, PSOCK, "revarp", hz/2); if (result != EWOULDBLOCK) break; } revarp_in_progress = 0; if (!myip_initialized) return ENETUNREACH; bcopy((void *)&srv_ip, serv_in, sizeof(*serv_in)); bcopy((void *)&myip, clnt_in, sizeof(*clnt_in)); return 0; } #ifdef DDB #include #include #include static void db_print_sa(const struct sockaddr *sa) { int len; const u_char *p; if (sa == 0) { db_printf("[NULL]"); return; } p = (const 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(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(void *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 rt_walktree(). * Return non-zero error to abort walk. */ static int db_show_rtentry(struct rtentry *rt, void *w) { 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_getkey(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)", rt->rt_ifp->if_xname); else db_printf("(NULL)"); db_printf(" ifa=%p\n", rt->rt_ifa); db_print_ifa(rt->rt_ifa); 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: "show arptab" */ void db_show_arptab(db_expr_t addr, bool have_addr, db_expr_t count, const char *modif) { rt_walktree(AF_INET, db_show_rtentry, NULL); } #endif SYSCTL_SETUP(sysctl_net_inet_arp_setup, "sysctl net.inet.arp subtree setup") { const struct sysctlnode *node; sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "net", NULL, NULL, 0, NULL, 0, CTL_NET, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "inet", NULL, NULL, 0, NULL, 0, CTL_NET, PF_INET, CTL_EOL); sysctl_createv(clog, 0, NULL, &node, CTLFLAG_PERMANENT, CTLTYPE_NODE, "arp", SYSCTL_DESCR("Address Resolution Protocol"), NULL, 0, NULL, 0, CTL_NET, PF_INET, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "prune", SYSCTL_DESCR("ARP cache pruning interval"), NULL, 0, &arpt_prune, 0, CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "keep", SYSCTL_DESCR("Valid ARP entry lifetime"), NULL, 0, &arpt_keep, 0, CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "down", SYSCTL_DESCR("Failed ARP entry lifetime"), NULL, 0, &arpt_down, 0, CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "refresh", SYSCTL_DESCR("ARP entry refresh interval"), NULL, 0, &arpt_refresh, 0, CTL_NET,PF_INET, node->sysctl_num, CTL_CREATE, CTL_EOL); } #endif /* INET */