/* $OpenBSD: if_ether.c,v 1.131 2014/07/12 18:44:23 tedu 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 */ #ifdef INET #include "carp.h" #include "bridge.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if NCARP > 0 #include #endif #if NBRIDGE > 0 #include #endif #define SDL(s) ((struct sockaddr_dl *)s) #define SRP(s) ((struct sockaddr_inarp *)s) /* * ARP trailer negotiation. Trailer protocol is not IP specific, * but ARP request/response use IP addresses. */ #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL /* timer values */ int arpt_prune = (5*60*1); /* walk list every 5 minutes */ int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ int arpt_down = 20; /* once declared down, don't send for 20 secs */ #define rt_expire rt_rmx.rmx_expire void arptfree(struct llinfo_arp *); void arptimer(void *); struct llinfo_arp *arplookup(u_int32_t, int, int, u_int); void in_arpinput(struct mbuf *); LIST_HEAD(, llinfo_arp) llinfo_arp; struct ifqueue arpintrq; 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; int revarp_in_progress; struct ifnet *revarp_ifp; #endif /* NFSCLIENT */ #ifdef DDB void db_print_sa(struct sockaddr *); void db_print_ifa(struct ifaddr *); void db_print_llinfo(caddr_t); int db_show_radix_node(struct radix_node *, void *, u_int); #endif static const struct sockaddr_dl null_sdl = { sizeof(null_sdl), AF_LINK }; /* * 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); for (la = LIST_FIRST(&llinfo_arp); la != NULL; la = nla) { struct rtentry *rt = la->la_rt; nla = LIST_NEXT(la, la_list); if (rt->rt_expire && rt->rt_expire <= time_second) arptfree(la); /* timer has expired; clear */ } splx(s); } void arp_rtrequest(int req, struct rtentry *rt) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; struct ifnet *ifp = rt->rt_ifp; struct ifaddr *ifa; struct mbuf *m; if (!arpinit_done) { static struct timeout arptimer_to; arpinit_done = 1; IFQ_SET_MAXLEN(&arpintrq, 50); /* XXX hate magic numbers */ /* * 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) 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) && !la)) { /* * Case 1: This route should come from a route to iface. */ rt_setgate(rt, rt_key(rt), (struct sockaddr *)&null_sdl, ifp->if_rdomain); gate = rt->rt_gateway; SDL(gate)->sdl_type = ifp->if_type; SDL(gate)->sdl_index = ifp->if_index; /* * Give this route an expiration time, even though * it's a "permanent" route, so that routes cloned * from it do not need their expiration time set. */ rt->rt_expire = time_second; if ((rt->rt_flags & RTF_CLONING) != 0) break; } /* Announce a new entry if requested. */ if (rt->rt_flags & RTF_ANNOUNCE) arprequest(ifp, &satosin(rt_key(rt))->sin_addr.s_addr, &satosin(rt_key(rt))->sin_addr.s_addr, (u_char *)LLADDR(SDL(gate))); /*FALLTHROUGH*/ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof(struct sockaddr_dl)) { log(LOG_DEBUG, "%s: bad gateway value: %s\n", __func__, ifp->if_xname); break; } SDL(gate)->sdl_type = ifp->if_type; SDL(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 = malloc(sizeof(*la), M_RTABLE, M_NOWAIT | M_ZERO); rt->rt_llinfo = (caddr_t)la; if (la == NULL) { log(LOG_DEBUG, "%s: malloc failed\n", __func__); break; } arp_inuse++; arp_allocated++; la->la_rt = rt; rt->rt_flags |= RTF_LLINFO; LIST_INSERT_HEAD(&llinfo_arp, 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) { rt->rt_expire = 0; SDL(gate)->sdl_alen = ETHER_ADDR_LEN; memcpy(LLADDR(SDL(gate)), ((struct arpcom *)ifp)->ac_enaddr, ETHER_ADDR_LEN); /* * XXX Since lo0 is in the default rdomain we * should not (ab)use it for any route related * to an interface of a different rdomain. */ 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. */ if (ifa != rt->rt_ifa) { ifafree(rt->rt_ifa); ifa->ifa_refcnt++; rt->rt_ifa = 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; while ((m = la->la_hold_head) != NULL) { la->la_hold_head = la->la_hold_head->m_nextpkt; la_hold_total--; m_freem(m); } free(la, M_RTABLE, 0); } } /* * 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, (struct rtentry *)0); } /* * Resolve an IP address into an ethernet address. If success, * desten is filled in. If there is no entry in arptab, * set one up and broadcast a request for the IP address. * Hold onto this mbuf and resend it once the address * is finally resolved. A return value of 1 indicates * that desten has been filled in and the packet should be sent * normally; a 0 return indicates that the packet has been * taken over here, either now or for later transmission. */ int arpresolve(struct arpcom *ac, struct rtentry *rt, struct mbuf *m, struct sockaddr *dst, u_char *desten) { struct llinfo_arp *la; struct sockaddr_dl *sdl; struct mbuf *mh; char addr[INET_ADDRSTRLEN]; if (m->m_flags & M_BCAST) { /* broadcast */ memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); return (1); } if (m->m_flags & M_MCAST) { /* multicast */ ETHER_MAP_IP_MULTICAST(&satosin(dst)->sin_addr, desten); return (1); } if (rt) { la = (struct llinfo_arp *)rt->rt_llinfo; if (la == NULL) log(LOG_DEBUG, "arpresolve: %s: route without link " "local address\n", inet_ntop(AF_INET, &satosin(dst)->sin_addr, addr, sizeof(addr))); } else { if ((la = arplookup(satosin(dst)->sin_addr.s_addr, RT_REPORT, 0, ac->ac_if.if_rdomain)) != NULL) rt = la->la_rt; else log(LOG_DEBUG, "arpresolve: %s: can't allocate llinfo\n", inet_ntop(AF_INET, &satosin(dst)->sin_addr, addr, sizeof(addr))); } if (la == 0 || rt == 0) { m_freem(m); return (0); } sdl = SDL(rt->rt_gateway); /* * Check the address family and length is valid, the address * is resolved; otherwise, try to resolve. */ if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { memcpy(desten, LLADDR(sdl), sdl->sdl_alen); return 1; } if (((struct ifnet *)ac)->if_flags & IFF_NOARP) { m_freem(m); return 0; } /* * 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 < MAX_HOLD_TOTAL && la_hold_total < nmbclust / 64) { if (la->la_hold_count >= MAX_HOLD_QUEUE) { mh = la->la_hold_head; la->la_hold_head = la->la_hold_head->m_nextpkt; if (mh == la->la_hold_tail) la->la_hold_tail = NULL; la->la_hold_count--; la_hold_total--; m_freem(mh); } if (la->la_hold_tail == NULL) la->la_hold_head = m; else la->la_hold_tail->m_nextpkt = m; la->la_hold_tail = m; la->la_hold_count++; la_hold_total++; } else { while ((mh = la->la_hold_head) != NULL) { la->la_hold_head = la->la_hold_head->m_nextpkt; la_hold_total--; m_freem(mh); } la->la_hold_tail = NULL; la->la_hold_count = 0; 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("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(&ac->ac_if, &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; while ((mh = la->la_hold_head) != NULL) { la->la_hold_head = la->la_hold_head->m_nextpkt; la_hold_total--; m_freem(mh); } la->la_hold_tail = NULL; la->la_hold_count = 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, len; for (;;) { s = splnet(); IF_DEQUEUE(&arpintrq, m); splx(s); if (m == NULL) break; #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); } } /* * ARP for Internet protocols on 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. */ void in_arpinput(struct mbuf *m) { struct ether_arp *ea; struct ifnet *ifp = m->m_pkthdr.rcvif; struct arpcom *ac = (struct arpcom *)ifp; struct ether_header *eh; struct llinfo_arp *la = 0; struct rtentry *rt; struct ifaddr *ifa; struct sockaddr_dl *sdl; struct sockaddr sa; struct in_addr isaddr, itaddr, myaddr; struct mbuf *mh, *mt; u_int8_t *enaddr = NULL; #if NCARP > 0 u_int8_t *ether_shost = NULL; #endif char addr[INET_ADDRSTRLEN]; int op; ea = mtod(m, struct ether_arp *); op = ntohs(ea->arp_op); if ((op != ARPOP_REQUEST) && (op != ARPOP_REPLY)) goto out; #if notyet if ((op == ARPOP_REPLY) && (m->m_flags & (M_BCAST|M_MCAST))) { log(LOG_ERR, "arp: received reply to broadcast or multicast address\n"); goto out; } #endif memcpy(&itaddr, ea->arp_tpa, sizeof(itaddr)); memcpy(&isaddr, ea->arp_spa, sizeof(isaddr)); /* First try: check target against our addresses */ TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if (ifa->ifa_addr->sa_family != AF_INET) continue; if (itaddr.s_addr != ifatoia(ifa)->ia_addr.sin_addr.s_addr) continue; #if NCARP > 0 if (ifp->if_type == IFT_CARP && ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == (IFF_UP|IFF_RUNNING))) { if (op == ARPOP_REPLY) break; if (carp_iamatch(ifatoia(ifa), ea->arp_sha, &enaddr, ðer_shost)) break; else goto out; } #endif break; } /* Second try: check source against our addresses */ if (ifa == NULL) { TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if (ifa->ifa_addr->sa_family != AF_INET) continue; if (isaddr.s_addr == ifatoia(ifa)->ia_addr.sin_addr.s_addr) break; } } /* Third try: not one of our addresses, just find an usable ia */ if (ifa == NULL) { TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) { if (ifa->ifa_addr->sa_family == AF_INET) break; } } if (ifa == NULL) goto out; if (!enaddr) enaddr = ac->ac_enaddr; myaddr = ifatoia(ifa)->ia_addr.sin_addr; if (!memcmp(ea->arp_sha, enaddr, sizeof(ea->arp_sha))) goto out; /* it's from me, ignore it. */ 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; } if (myaddr.s_addr && isaddr.s_addr == myaddr.s_addr) { 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 = myaddr; goto reply; } la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0, rtable_l2(m->m_pkthdr.ph_rtableid)); if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { if (sdl->sdl_alen) { if (memcmp(ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { if (rt->rt_flags & RTF_PERMANENT_ARP) { 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), ac->ac_if.if_xname); goto out; } else if (rt->rt_ifp != &ac->ac_if) { #if NCARP > 0 if (ac->ac_if.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), ac->ac_if.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), ac->ac_if.if_xname); rt->rt_expire = 1; /* no longer static */ } } } else if (rt->rt_ifp != &ac->ac_if && #if NBRIDGE > 0 !SAME_BRIDGE(ac->ac_if.if_bridgeport, rt->rt_ifp->if_bridgeport) && #endif #if NCARP > 0 !(rt->rt_ifp->if_type == IFT_CARP && rt->rt_ifp->if_carpdev == &ac->ac_if) && !(ac->ac_if.if_type == IFT_CARP && ac->ac_if.if_carpdev == rt->rt_ifp) && #endif 1) { 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), ac->ac_if.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; la->la_asked = 0; rt_sendmsg(rt, RTM_RESOLVE, rt->rt_ifp->if_rdomain); while ((mh = la->la_hold_head) != NULL) { if ((la->la_hold_head = mh->m_nextpkt) == NULL) la->la_hold_tail = NULL; la->la_hold_count--; la_hold_total--; mt = la->la_hold_tail; (*ac->ac_if.if_output)(&ac->ac_if, mh, rt_key(rt), rt); if (la->la_hold_tail == mh) { /* mbuf is back in queue. Discard. */ la->la_hold_tail = mt; if (la->la_hold_tail) la->la_hold_tail->m_nextpkt = NULL; else la->la_hold_head = NULL; la->la_hold_count--; la_hold_total--; m_freem(mh); } } } reply: if (op != ARPOP_REQUEST) { out: m_freem(m); return; } if (itaddr.s_addr == myaddr.s_addr) { /* I am the target */ memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); } else { la = arplookup(itaddr.s_addr, 0, SIN_PROXY, rtable_l2(m->m_pkthdr.ph_rtableid)); if (la == 0) goto out; rt = la->la_rt; if (rt->rt_ifp->if_type == IFT_CARP && ifp->if_type != IFT_CARP) goto out; memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); sdl = SDL(rt->rt_gateway); memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); } 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)); #if NCARP > 0 if (ether_shost) enaddr = ether_shost; #endif 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); (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); return; } /* * Free an arp entry. */ void arptfree(struct llinfo_arp *la) { struct rtentry *rt = la->la_rt; struct sockaddr_dl *sdl; u_int tid = 0; if (rt == NULL) 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; } if (rt->rt_ifp) tid = rt->rt_ifp->if_rdomain; rtdeletemsg(rt, tid); } /* * Lookup or enter a new address in arptab. */ struct llinfo_arp * arplookup(u_int32_t addr, int create, int proxy, u_int tableid) { struct rtentry *rt; struct sockaddr_inarp sin; 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; rt = rtalloc1((struct sockaddr *)&sin, create, tableid); if (rt == 0) return (0); rt->rt_refcnt--; if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 || rt->rt_gateway->sa_family != AF_LINK) { if (create) { if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_CLONED) != 0) { struct rt_addrinfo info; memset(&info, 0, sizeof(info)); info.rti_info[RTAX_DST] = rt_key(rt); info.rti_info[RTAX_GATEWAY] = rt->rt_gateway; info.rti_info[RTAX_NETMASK] = rt_mask(rt); rtrequest1(RTM_DELETE, &info, rt->rt_priority, NULL, tableid); } } return (0); } return ((struct llinfo_arp *)rt->rt_llinfo); } /* * Check whether we do proxy ARP for this address and we point to ourselves. */ int arpproxy(struct in_addr in, u_int rdomain) { struct llinfo_arp *la; struct ifnet *ifp; int found = 0; la = arplookup(in.s_addr, 0, SIN_PROXY, rdomain); if (la == NULL) return (0); TAILQ_FOREACH(ifp, &ifnet, if_list) { if (ifp->if_rdomain != rdomain) continue; if (!memcmp(LLADDR((struct sockaddr_dl *)la->la_rt->rt_gateway), LLADDR(ifp->if_sadl), ETHER_ADDR_LEN)) { found = 1; break; } } return (found); } void arp_ifinit(struct arpcom *ac, struct ifaddr *ifa) { /* Warn the user if another station has this IP address. */ arprequest(&ac->ac_if, &satosin(ifa->ifa_addr)->sin_addr.s_addr, &satosin(ifa->ifa_addr)->sin_addr.s_addr, ac->ac_enaddr); ifa->ifa_rtrequest = arp_rtrequest; } /* * 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) { #ifdef NFSCLIENT struct ifnet *ifp; #endif /* NFSCLIENT */ 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_in_progress) goto out; ifp = m->m_pkthdr.rcvif; if (ifp != revarp_ifp) /* !same interface */ goto out; if (revarp_finished) goto wake; if (memcmp(ar->arp_tha, ((struct arpcom *)ifp)->ac_enaddr, 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); } /* * 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, (struct rtentry *)0); } #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_ifp = ifp; revarp_in_progress = 1; while (count--) { revarprequest(ifp); result = tsleep((caddr_t)&revarp_myip, PSOCK, "revarp", hz/2); if (result != EWOULDBLOCK) break; } revarp_in_progress = 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 */ #ifdef DDB #include #include #include void db_print_sa(struct sockaddr *sa) { int len; u_char *p; if (sa == 0) { db_printf("[NULL]"); return; } p = (u_char *)sa; len = sa->sa_len; db_printf("["); while (len > 0) { db_printf("%d", *p); p++; len--; if (len) db_printf(","); } db_printf("]\n"); } 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); } void db_print_llinfo(caddr_t li) { struct llinfo_arp *la; if (li == 0) return; la = (struct llinfo_arp *)li; db_printf(" la_rt=%p la_hold_head=%p, la_asked=0x%lx\n", la->la_rt, la->la_hold_head, la->la_asked); } /* * Function to pass to rn_walktree(). * Return non-zero error to abort walk. */ int db_show_radix_node(struct radix_node *rn, void *w, u_int id) { struct rtentry *rt = (struct rtentry *)rn; db_printf("rtentry=%p", rt); db_printf(" flags=0x%x refcnt=%d use=%llu expire=%lld rtableid=%u\n", rt->rt_flags, rt->rt_refcnt, rt->rt_use, rt->rt_expire, id); db_printf(" key="); db_print_sa(rt_key(rt)); db_printf(" mask="); db_print_sa(rt_mask(rt)); db_printf(" gw="); db_print_sa(rt->rt_gateway); db_printf(" ifp=%p ", rt->rt_ifp); if (rt->rt_ifp) db_printf("(%s)", 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: "call db_show_arptab" */ int db_show_arptab(void) { struct radix_node_head *rnh; rnh = rtable_get(0, AF_INET); db_printf("Route tree for AF_INET\n"); if (rnh == NULL) { db_printf(" (not initialized)\n"); return (0); } rn_walktree(rnh, db_show_radix_node, NULL); return (0); } #endif #endif /* INET */