/* $OpenBSD: if_ether.c,v 1.190 2015/11/20 10:51:30 mpi Exp $ */ /* $NetBSD: if_ether.c,v 1.31 1996/05/11 12:59:58 mycroft 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. 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 */ #include "carp.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if NCARP > 0 #include #endif /* * ARP trailer negotiation. Trailer protocol is not IP specific, * but ARP request/response use IP addresses. */ #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL struct llinfo_arp { LIST_ENTRY(llinfo_arp) la_list; struct rtentry *la_rt; /* backpointer to rtentry */ long la_asked; /* last time we QUERIED */ struct mbuf_list la_ml; /* packet hold queue */ }; #define LA_HOLD_QUEUE 10 #define LA_HOLD_TOTAL 100 /* 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 */ void arptfree(struct rtentry *); void arptimer(void *); struct rtentry *arplookup(u_int32_t, int, int, u_int); void in_arpinput(struct mbuf *); void revarpinput(struct mbuf *); void in_revarpinput(struct mbuf *); LIST_HEAD(, llinfo_arp) arp_list; struct pool arp_pool; /* pool for llinfo_arp structures */ /* XXX hate magic numbers */ struct niqueue arpintrq = NIQUEUE_INITIALIZER(50, NETISR_ARP); struct niqueue rarpintrq = NIQUEUE_INITIALIZER(50, NETISR_ARP); int arp_inuse, arp_allocated; int arp_maxtries = 5; int arpinit_done; int la_hold_total; #ifdef NFSCLIENT /* revarp state */ struct in_addr revarp_myip, revarp_srvip; int revarp_finished; unsigned int revarp_ifidx; #endif /* NFSCLIENT */ /* * Timeout routine. Age arp_tab entries periodically. */ /* ARGSUSED */ void arptimer(void *arg) { struct timeout *to = (struct timeout *)arg; int s; struct llinfo_arp *la, *nla; s = splsoftnet(); timeout_add_sec(to, arpt_prune); LIST_FOREACH_SAFE(la, &arp_list, la_list, nla) { struct rtentry *rt = la->la_rt; if (rt->rt_expire && rt->rt_expire <= time_second) arptfree(rt); /* timer has expired; clear */ } splx(s); } void arp_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; struct ifaddr *ifa; if (!arpinit_done) { static struct timeout arptimer_to; arpinit_done = 1; pool_init(&arp_pool, sizeof(struct llinfo_arp), 0, 0, 0, "arp", NULL); /* * We generate expiration times from time.tv_sec * so avoid accidently creating permanent routes. */ if (time_second == 0) { time_second++; } timeout_set(&arptimer_to, arptimer, &arptimer_to); timeout_add_sec(&arptimer_to, 1); } if (rt->rt_flags & (RTF_GATEWAY|RTF_BROADCAST)) 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 && rt_mask(rt) && satosin(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) rt->rt_flags |= RTF_CLONING; if (rt->rt_flags & RTF_CLONING || ((rt->rt_flags & (RTF_LLINFO | RTF_LOCAL)) && !la)) { /* * 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; if ((rt->rt_flags & RTF_CLONING) != 0) break; } /* * Announce a new entry if requested or warn the user * if another station has this IP address. */ if (rt->rt_flags & (RTF_ANNOUNCE|RTF_LOCAL)) arprequest(ifp, &satosin(rt_key(rt))->sin_addr.s_addr, &satosin(rt_key(rt))->sin_addr.s_addr, (u_char *)LLADDR(satosdl(gate))); /*FALLTHROUGH*/ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof(struct sockaddr_dl)) { log(LOG_DEBUG, "%s: bad gateway value: %s\n", __func__, ifp->if_xname); 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. */ la = pool_get(&arp_pool, PR_NOWAIT | PR_ZERO); rt->rt_llinfo = (caddr_t)la; if (la == NULL) { log(LOG_DEBUG, "%s: pool get failed\n", __func__); break; } arp_inuse++; arp_allocated++; ml_init(&la->la_ml); la->la_rt = rt; rt->rt_flags |= RTF_LLINFO; LIST_INSERT_HEAD(&arp_list, la, la_list); TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if ((ifa->ifa_addr->sa_family == AF_INET) && ifatoia(ifa)->ia_addr.sin_addr.s_addr == satosin(rt_key(rt))->sin_addr.s_addr) break; } if (ifa) { KASSERT(ifa == rt->rt_ifa); rt->rt_expire = 0; } break; case RTM_DELETE: if (la == NULL) break; arp_inuse--; LIST_REMOVE(la, la_list); rt->rt_llinfo = 0; rt->rt_flags &= ~RTF_LLINFO; la_hold_total -= ml_purge(&la->la_ml); pool_put(&arp_pool, la); } } /* * 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, u_int32_t *sip, u_int32_t *tip, u_int8_t *enaddr) { struct mbuf *m; struct ether_header *eh; 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); m->m_pkthdr.ph_rtableid = ifp->if_rdomain; MH_ALIGN(m, sizeof(*ea)); ea = mtod(m, struct ether_arp *); eh = (struct ether_header *)sa.sa_data; memset(ea, 0, sizeof(*ea)); memcpy(eh->ether_dhost, etherbroadcastaddr, 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); memcpy(eh->ether_shost, enaddr, sizeof(eh->ether_shost)); memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); sa.sa_family = pseudo_AF_HDRCMPLT; sa.sa_len = sizeof(sa); m->m_flags |= M_BCAST; 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 0 indicates * that desten has been filled in and the packet should be sent * normally; A return value of EAGAIN indicates that the packet * has been taken over here, either now or for later transmission. * Any other return value indicates an error. */ int arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, struct sockaddr *dst, u_char *desten) { struct arpcom *ac = (struct arpcom *)ifp; struct llinfo_arp *la = NULL; struct sockaddr_dl *sdl; struct rtentry *rt = NULL; struct mbuf *mh; char addr[INET_ADDRSTRLEN]; int error, created = 0; if (m->m_flags & M_BCAST) { /* broadcast */ memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); return (0); } if (m->m_flags & M_MCAST) { /* multicast */ ETHER_MAP_IP_MULTICAST(&satosin(dst)->sin_addr, desten); return (0); } if (rt0 != NULL) { error = rt_checkgate(ifp, rt0, dst, m->m_pkthdr.ph_rtableid, &rt); if (error) { m_freem(m); return (error); } if ((rt->rt_flags & RTF_LLINFO) == 0) { log(LOG_DEBUG, "%s: %s: route contains no arp" " information\n", __func__, inet_ntop(AF_INET, &satosin(rt_key(rt))->sin_addr, addr, sizeof(addr))); m_freem(m); return (EINVAL); } la = (struct llinfo_arp *)rt->rt_llinfo; if (la == NULL) log(LOG_DEBUG, "%s: %s: route without link " "local address\n", __func__, inet_ntop(AF_INET, &satosin(dst)->sin_addr, addr, sizeof(addr))); } else { rt = arplookup(satosin(dst)->sin_addr.s_addr, 1, 0, ifp->if_rdomain); if (rt != NULL) { created = 1; la = ((struct llinfo_arp *)rt->rt_llinfo); } if (la == NULL) log(LOG_DEBUG, "%s: %s: can't allocate llinfo\n", __func__, inet_ntop(AF_INET, &satosin(dst)->sin_addr, addr, sizeof(addr))); } if (la == NULL || rt == NULL) goto bad; sdl = satosdl(rt->rt_gateway); if (sdl->sdl_alen > 0 && sdl->sdl_alen != ETHER_ADDR_LEN) { log(LOG_DEBUG, "%s: %s: incorrect arp information\n", __func__, inet_ntop(AF_INET, &satosin(dst)->sin_addr, addr, sizeof(addr))); goto bad; } /* * 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) { memcpy(desten, LLADDR(sdl), sdl->sdl_alen); if (created) rtfree(rt); return (0); } if (ifp->if_flags & IFF_NOARP) goto bad; /* * There is an arptab entry, but no ethernet address * response yet. Insert mbuf in hold queue if below limit * if above the limit free the queue without queuing the new packet. */ if (la_hold_total < LA_HOLD_TOTAL && la_hold_total < nmbclust / 64) { if (ml_len(&la->la_ml) >= LA_HOLD_QUEUE) { mh = ml_dequeue(&la->la_ml); la_hold_total--; m_freem(mh); } ml_enqueue(&la->la_ml, m); la_hold_total++; } else { la_hold_total -= ml_purge(&la->la_ml); m_freem(m); } /* * Re-send the ARP request when appropriate. */ #ifdef DIAGNOSTIC if (rt->rt_expire == 0) { /* This should never happen. (Should it? -gwr) */ printf("%s: unresolved and rt_expire == 0\n", __func__); /* 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, &satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr, &satosin(dst)->sin_addr.s_addr, #if NCARP > 0 (rt->rt_ifp->if_type == IFT_CARP) ? ((struct arpcom *) rt->rt_ifp->if_softc )->ac_enaddr : #endif ac->ac_enaddr); else { rt->rt_flags |= RTF_REJECT; rt->rt_expire += arpt_down; la->la_asked = 0; la_hold_total -= ml_purge(&la->la_ml); } } } if (created) rtfree(rt); return (EAGAIN); bad: m_freem(m); if (created) rtfree(rt); return (EINVAL); } /* * 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 len; while ((m = niq_dequeue(&arpintrq)) != NULL) { #ifdef DIAGNOSTIC if ((m->m_flags & M_PKTHDR) == 0) panic("arpintr"); #endif len = sizeof(struct arphdr); if (m->m_len < len && (m = m_pullup(m, len)) == NULL) continue; ar = mtod(m, struct arphdr *); if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) { m_freem(m); continue; } len += 2 * (ar->ar_hln + ar->ar_pln); if (m->m_len < len && (m = m_pullup(m, len)) == NULL) continue; switch (ntohs(ar->ar_pro)) { case ETHERTYPE_IP: case ETHERTYPE_IPTRAILERS: in_arpinput(m); continue; } m_freem(m); } while ((m = niq_dequeue(&rarpintrq)) != NULL) revarpinput(m); } /* * ARP for Internet protocols on Ethernet, RFC 826. * In addition, a sanity check is performed on the sender * protocol address, to catch impersonators. */ void in_arpinput(struct mbuf *m) { struct ether_arp *ea; struct ifnet *ifp; struct ether_header *eh; struct llinfo_arp *la = NULL; struct rtentry *rt = NULL; struct sockaddr_dl *sdl; struct sockaddr sa; struct sockaddr_in sin; struct in_addr isaddr, itaddr; struct mbuf *mh; uint8_t enaddr[ETHER_ADDR_LEN]; char addr[INET_ADDRSTRLEN]; int op, changed = 0, target = 0; unsigned int len, rdomain; rdomain = rtable_l2(m->m_pkthdr.ph_rtableid); ifp = if_get(m->m_pkthdr.ph_ifidx); if (ifp == NULL) { m_freem(m); return; } ea = mtod(m, struct ether_arp *); op = ntohs(ea->arp_op); if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) goto out; memcpy(&itaddr, ea->arp_tpa, sizeof(itaddr)); memcpy(&isaddr, ea->arp_spa, sizeof(isaddr)); memset(&sin, 0, sizeof(sin)); sin.sin_len = sizeof(sin); sin.sin_family = AF_INET; if (ETHER_IS_MULTICAST(&ea->arp_sha[0])) { if (!memcmp(ea->arp_sha, etherbroadcastaddr, sizeof (ea->arp_sha))) { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_ERR, "arp: ether address is broadcast for " "IP address %s!\n", addr); goto out; } } memcpy(enaddr, LLADDR(ifp->if_sadl), ETHER_ADDR_LEN); if (!memcmp(ea->arp_sha, enaddr, sizeof(ea->arp_sha))) goto out; /* it's from me, ignore it. */ /* Check target against our interface addresses. */ sin.sin_addr = itaddr; rt = rtalloc(sintosa(&sin), 0, rdomain); if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_LOCAL) && rt->rt_ifidx == ifp->if_index) target = 1; rtfree(rt); rt = NULL; #if NCARP > 0 if (target && op == ARPOP_REQUEST && ifp->if_type == IFT_CARP && !carp_iamatch(ifp, enaddr)) goto out; #endif /* Do we have an ARP cache for the sender? Create if we are target. */ rt = arplookup(isaddr.s_addr, target, 0, rdomain); /* Check sender against our interface addresses. */ if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_LOCAL) && rt->rt_ifidx == ifp->if_index && isaddr.s_addr != INADDR_ANY) { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_ERR, "duplicate IP address %s sent from ethernet address %s\n", addr, ether_sprintf(ea->arp_sha)); itaddr = isaddr; } else if (rt != NULL && (sdl = satosdl(rt->rt_gateway)) != NULL) { la = (struct llinfo_arp *)rt->rt_llinfo; if (sdl->sdl_alen) { if (memcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { if (rt->rt_flags & (RTF_PERMANENT_ARP|RTF_LOCAL)) { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_WARNING, "arp: attempt to" " overwrite permanent entry for %s" " by %s on %s\n", addr, ether_sprintf(ea->arp_sha), ifp->if_xname); goto out; } else if (rt->rt_ifp != ifp) { #if NCARP > 0 if (ifp->if_type != IFT_CARP) #endif { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_WARNING, "arp: attempt" " to overwrite entry for" " %s on %s by %s on %s\n", addr, rt->rt_ifp->if_xname, ether_sprintf(ea->arp_sha), ifp->if_xname); } goto out; } else { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_INFO, "arp info overwritten for" " %s by %s on %s\n", addr, ether_sprintf(ea->arp_sha), ifp->if_xname); rt->rt_expire = 1;/* no longer static */ } changed = 1; } } else if (!if_isconnected(ifp, rt->rt_ifidx)) { inet_ntop(AF_INET, &isaddr, addr, sizeof(addr)); log(LOG_WARNING, "arp: attempt to add entry for %s " "on %s by %s on %s\n", addr, rt->rt_ifp->if_xname, ether_sprintf(ea->arp_sha), ifp->if_xname); goto out; } sdl->sdl_alen = sizeof(ea->arp_sha); memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); if (rt->rt_expire) rt->rt_expire = time_second + arpt_keep; rt->rt_flags &= ~RTF_REJECT; /* Notify userland that an ARP resolution has been done. */ if (la->la_asked || changed) rt_sendmsg(rt, RTM_RESOLVE, ifp->if_rdomain); la->la_asked = 0; while ((len = ml_len(&la->la_ml)) != 0) { mh = ml_dequeue(&la->la_ml); la_hold_total--; ifp->if_output(ifp, mh, rt_key(rt), rt); if (ml_len(&la->la_ml) == len) { /* mbuf is back in queue. Discard. */ while ((mh = ml_dequeue(&la->la_ml)) != NULL) { la_hold_total--; m_freem(mh); } break; } } } if (op != ARPOP_REQUEST) { out: rtfree(rt); if_put(ifp); m_freem(m); return; } rtfree(rt); if (target) { /* We are the target and already have all info for the reply */ memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); memcpy(ea->arp_sha, LLADDR(ifp->if_sadl), sizeof(ea->arp_sha)); } else { rt = arplookup(itaddr.s_addr, 0, SIN_PROXY, rdomain); if (rt == NULL) goto out; #if NCARP > 0 if (rt->rt_ifp->if_type == IFT_CARP && ifp->if_type != IFT_CARP) goto out; #endif memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); sdl = satosdl(rt->rt_gateway); memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); rtfree(rt); } memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); memcpy(ea->arp_spa, &itaddr, 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; memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); memcpy(eh->ether_shost, enaddr, sizeof(eh->ether_shost)); eh->ether_type = htons(ETHERTYPE_ARP); sa.sa_family = pseudo_AF_HDRCMPLT; sa.sa_len = sizeof(sa); ifp->if_output(ifp, m, &sa, NULL); if_put(ifp); } /* * Free an arp entry. */ void arptfree(struct rtentry *rt) { struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; struct sockaddr_dl *sdl = satosdl(rt->rt_gateway); struct ifnet *ifp; ifp = if_get(rt->rt_ifidx); if ((sdl != NULL) && (sdl->sdl_family == AF_LINK)) { sdl->sdl_alen = 0; la->la_asked = 0; } rtdeletemsg(rt, ifp->if_rdomain); if_put(ifp); } /* * Lookup or enter a new address in arptab. */ struct rtentry * arplookup(u_int32_t addr, int create, int proxy, u_int tableid) { struct rtentry *rt; struct sockaddr_inarp sin; int flags; memset(&sin, 0, sizeof(sin)); sin.sin_len = sizeof(sin); sin.sin_family = AF_INET; sin.sin_addr.s_addr = addr; sin.sin_other = proxy ? SIN_PROXY : 0; flags = (create) ? (RT_REPORT|RT_RESOLVE) : 0; rt = rtalloc((struct sockaddr *)&sin, flags, tableid); if (rt == NULL) return (NULL); if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || rt->rt_gateway->sa_family != AF_LINK) { if (create && (rt->rt_flags & RTF_CLONED)) rtdeletemsg(rt, tableid); rtfree(rt); return (NULL); } return (rt); } /* * Check whether we do proxy ARP for this address and we point to ourselves. */ int arpproxy(struct in_addr in, unsigned int rtableid) { struct sockaddr_dl *sdl; struct rtentry *rt; struct ifnet *ifp; int found = 0; rt = arplookup(in.s_addr, 0, SIN_PROXY, rtableid); if (!rtisvalid(rt)) { rtfree(rt); return (0); } /* Check that arp information are correct. */ sdl = satosdl(rt->rt_gateway); if (sdl->sdl_alen != ETHER_ADDR_LEN) { rtfree(rt); return (0); } ifp = if_get(rt->rt_ifidx); if (ifp == NULL) { rtfree(rt); return (0); } if (!memcmp(LLADDR(sdl), LLADDR(ifp->if_sadl), sdl->sdl_alen)) found = 1; if_put(ifp); rtfree(rt); return (found); } /* * Called from 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 (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 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 = NULL; 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; } #ifdef NFSCLIENT if (revarp_ifidx == 0) goto out; if (revarp_ifidx != m->m_pkthdr.ph_ifidx) /* !same interface */ goto out; if (revarp_finished) goto wake; ifp = if_get(revarp_ifidx); if (ifp == NULL) goto out; if (memcmp(ar->arp_tha, LLADDR(ifp->if_sadl), sizeof(ar->arp_tha))) goto out; memcpy(&revarp_srvip, ar->arp_spa, sizeof(revarp_srvip)); memcpy(&revarp_myip, ar->arp_tpa, sizeof(revarp_myip)); revarp_finished = 1; wake: /* Do wakeup every time in case it was missed. */ wakeup((caddr_t)&revarp_myip); #endif out: m_freem(m); if_put(ifp); } /* * 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 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; memset(ea, 0, sizeof(*ea)); memcpy(eh->ether_dhost, etherbroadcastaddr, 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); memcpy(eh->ether_shost, ac->ac_enaddr, sizeof(ea->arp_tha)); memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); memcpy(ea->arp_tha, ac->ac_enaddr, sizeof(ea->arp_tha)); sa.sa_family = pseudo_AF_HDRCMPLT; sa.sa_len = sizeof(sa); m->m_flags |= M_BCAST; ifp->if_output(ifp, m, &sa, NULL); } #ifdef NFSCLIENT /* * 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; if (revarp_finished) return EIO; revarp_ifidx = ifp->if_index; while (count--) { revarprequest(ifp); result = tsleep((caddr_t)&revarp_myip, PSOCK, "revarp", hz/2); if (result != EWOULDBLOCK) break; } revarp_ifidx = 0; if (!revarp_finished) return ENETUNREACH; memcpy(serv_in, &revarp_srvip, sizeof(*serv_in)); memcpy(clnt_in, &revarp_myip, sizeof(*clnt_in)); return 0; } /* For compatibility: only saves interface address. */ int revarpwhoami(struct in_addr *in, struct ifnet *ifp) { struct in_addr server; return (revarpwhoarewe(ifp, &server, in)); } #endif /* NFSCLIENT */