/* * Copyright (c) 2004-2014 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1982, 1989, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CONST_LLADDR(s) ((const u_char*)((s)->sdl_data + (s)->sdl_nlen)) static const size_t MAX_HW_LEN = 10; /* * Synchronization notes: * * The global list of ARP entries are stored in llinfo_arp; an entry * gets inserted into the list when the route is created and gets * removed from the list when it is deleted; this is done as part * of RTM_ADD/RTM_RESOLVE/RTM_DELETE in arp_rtrequest(). * * Because rnh_lock and rt_lock for the entry are held during those * operations, the same locks (and thus lock ordering) must be used * elsewhere to access the relevant data structure fields: * * la_le.{le_next,le_prev}, la_rt * * - Routing lock (rnh_lock) * * la_hold, la_asked, la_llreach, la_lastused, la_flags * * - Routing entry lock (rt_lock) * * Due to the dependency on rt_lock, llinfo_arp has the same lifetime * as the route entry itself. When a route is deleted (RTM_DELETE), * it is simply removed from the global list but the memory is not * freed until the route itself is freed. */ struct llinfo_arp { /* * The following are protected by rnh_lock */ LIST_ENTRY(llinfo_arp) la_le; struct rtentry *la_rt; /* * The following are protected by rt_lock */ struct mbuf *la_hold; /* last packet until resolved/timeout */ struct if_llreach *la_llreach; /* link-layer reachability record */ u_int64_t la_lastused; /* last used timestamp */ u_int32_t la_asked; /* # of requests sent */ u_int32_t la_maxtries; /* retry limit */ uint32_t la_flags; #define LLINFO_RTRFAIL_EVTSENT 0x1 /* sent an ARP event */ }; static LIST_HEAD(, llinfo_arp) llinfo_arp; static int arp_timeout_run; /* arp_timeout is scheduled to run */ static void arp_timeout(void *); static void arp_sched_timeout(struct timeval *); static void arptfree(struct llinfo_arp *, void *); static errno_t arp_lookup_route(const struct in_addr *, int, int, route_t *, unsigned int); static int arp_getstat SYSCTL_HANDLER_ARGS; static struct llinfo_arp *arp_llinfo_alloc(int); static void arp_llinfo_free(void *); static void arp_llinfo_purge(struct rtentry *); static void arp_llinfo_get_ri(struct rtentry *, struct rt_reach_info *); static void arp_llinfo_get_iflri(struct rtentry *, struct ifnet_llreach_info *); static __inline void arp_llreach_use(struct llinfo_arp *); static __inline int arp_llreach_reachable(struct llinfo_arp *); static void arp_llreach_alloc(struct rtentry *, struct ifnet *, void *, unsigned int, boolean_t); extern int tvtohz(struct timeval *); static int arpinit_done; SYSCTL_DECL(_net_link_ether); SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW|CTLFLAG_LOCKED, 0, ""); /* timer values */ static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW | CTLFLAG_LOCKED, &arpt_prune, 0, ""); static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW | CTLFLAG_LOCKED, &arpt_keep, 0, ""); static int arpt_down = 20; /* once declared down, don't send for 20 sec */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW | CTLFLAG_LOCKED, &arpt_down, 0, ""); static int arp_llreach_base = (LL_BASE_REACHABLE / 1000); /* seconds */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, arp_llreach_base, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_llreach_base, LL_BASE_REACHABLE, "default ARP link-layer reachability max lifetime (in seconds)"); #define ARP_UNICAST_LIMIT 5 /* # of probes until ARP refresh broadcast */ static u_int32_t arp_unicast_lim = ARP_UNICAST_LIMIT; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, arp_unicast_lim, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_unicast_lim, ARP_UNICAST_LIMIT, "number of unicast ARP refresh probes before using broadcast"); static u_int32_t arp_maxtries = 5; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_maxtries, 0, ""); static int useloopback = 1; /* use loopback interface for local traffic */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW | CTLFLAG_LOCKED, &useloopback, 0, ""); static int arp_proxyall = 0; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_proxyall, 0, ""); static int arp_sendllconflict = 0; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, sendllconflict, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_sendllconflict, 0, ""); static int log_arp_warnings = 0; /* Thread safe: no accumulated state */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_warnings, CTLFLAG_RW | CTLFLAG_LOCKED, &log_arp_warnings, 0, "log arp warning messages"); static int keep_announcements = 1; /* Thread safe: no aging of state */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, keep_announcements, CTLFLAG_RW | CTLFLAG_LOCKED, &keep_announcements, 0, "keep arp announcements"); static int send_conflicting_probes = 1; /* Thread safe: no accumulated state */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, send_conflicting_probes, CTLFLAG_RW | CTLFLAG_LOCKED, &send_conflicting_probes, 0, "send conflicting link-local arp probes"); static int arp_verbose; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, verbose, CTLFLAG_RW | CTLFLAG_LOCKED, &arp_verbose, 0, ""); struct arpstat arpstat; SYSCTL_PROC(_net_link_ether_inet, OID_AUTO, stats, CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0, arp_getstat, "S,arpstat", "ARP statistics (struct arpstat, net/if_arp.h)"); /* these are deprecated (read-only); use net.link.generic.system node instead */ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, apple_hwcksum_tx, CTLFLAG_RD | CTLFLAG_LOCKED, &hwcksum_tx, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, apple_hwcksum_rx, CTLFLAG_RD | CTLFLAG_LOCKED, &hwcksum_rx, 0, ""); static struct zone *llinfo_arp_zone; #define LLINFO_ARP_ZONE_MAX 256 /* maximum elements in zone */ #define LLINFO_ARP_ZONE_NAME "llinfo_arp" /* name for zone */ void arp_init(void) { VERIFY(!arpinit_done); LIST_INIT(&llinfo_arp); llinfo_arp_zone = zinit(sizeof (struct llinfo_arp), LLINFO_ARP_ZONE_MAX * sizeof (struct llinfo_arp), 0, LLINFO_ARP_ZONE_NAME); if (llinfo_arp_zone == NULL) panic("%s: failed allocating llinfo_arp_zone", __func__); zone_change(llinfo_arp_zone, Z_EXPAND, TRUE); zone_change(llinfo_arp_zone, Z_CALLERACCT, FALSE); arpinit_done = 1; } static struct llinfo_arp * arp_llinfo_alloc(int how) { struct llinfo_arp *la; la = (how == M_WAITOK) ? zalloc(llinfo_arp_zone) : zalloc_noblock(llinfo_arp_zone); if (la != NULL) bzero(la, sizeof (*la)); return (la); } static void arp_llinfo_free(void *arg) { struct llinfo_arp *la = arg; if (la->la_le.le_next != NULL || la->la_le.le_prev != NULL) { panic("%s: trying to free %p when it is in use", __func__, la); /* NOTREACHED */ } /* Just in case there's anything there, free it */ if (la->la_hold != NULL) { m_freem(la->la_hold); la->la_hold = NULL; arpstat.purged++; } /* Purge any link-layer info caching */ VERIFY(la->la_rt->rt_llinfo == la); if (la->la_rt->rt_llinfo_purge != NULL) la->la_rt->rt_llinfo_purge(la->la_rt); zfree(llinfo_arp_zone, la); } static void arp_llinfo_purge(struct rtentry *rt) { struct llinfo_arp *la = rt->rt_llinfo; RT_LOCK_ASSERT_HELD(rt); VERIFY(rt->rt_llinfo_purge == arp_llinfo_purge && la != NULL); if (la->la_llreach != NULL) { RT_CONVERT_LOCK(rt); ifnet_llreach_free(la->la_llreach); la->la_llreach = NULL; } la->la_lastused = 0; } static void arp_llinfo_get_ri(struct rtentry *rt, struct rt_reach_info *ri) { struct llinfo_arp *la = rt->rt_llinfo; struct if_llreach *lr = la->la_llreach; if (lr == NULL) { bzero(ri, sizeof (*ri)); ri->ri_rssi = IFNET_RSSI_UNKNOWN; ri->ri_lqm = IFNET_LQM_THRESH_OFF; ri->ri_npm = IFNET_NPM_THRESH_UNKNOWN; } else { IFLR_LOCK(lr); /* Export to rt_reach_info structure */ ifnet_lr2ri(lr, ri); /* Export ARP send expiration (calendar) time */ ri->ri_snd_expire = ifnet_llreach_up2calexp(lr, la->la_lastused); IFLR_UNLOCK(lr); } } static void arp_llinfo_get_iflri(struct rtentry *rt, struct ifnet_llreach_info *iflri) { struct llinfo_arp *la = rt->rt_llinfo; struct if_llreach *lr = la->la_llreach; if (lr == NULL) { bzero(iflri, sizeof (*iflri)); iflri->iflri_rssi = IFNET_RSSI_UNKNOWN; iflri->iflri_lqm = IFNET_LQM_THRESH_OFF; iflri->iflri_npm = IFNET_NPM_THRESH_UNKNOWN; } else { IFLR_LOCK(lr); /* Export to ifnet_llreach_info structure */ ifnet_lr2iflri(lr, iflri); /* Export ARP send expiration (uptime) time */ iflri->iflri_snd_expire = ifnet_llreach_up2upexp(lr, la->la_lastused); IFLR_UNLOCK(lr); } } void arp_llreach_set_reachable(struct ifnet *ifp, void *addr, unsigned int alen) { /* Nothing more to do if it's disabled */ if (arp_llreach_base == 0) return; ifnet_llreach_set_reachable(ifp, ETHERTYPE_IP, addr, alen); } static __inline void arp_llreach_use(struct llinfo_arp *la) { if (la->la_llreach != NULL) la->la_lastused = net_uptime(); } static __inline int arp_llreach_reachable(struct llinfo_arp *la) { struct if_llreach *lr; const char *why = NULL; /* Nothing more to do if it's disabled; pretend it's reachable */ if (arp_llreach_base == 0) return (1); if ((lr = la->la_llreach) == NULL) { /* * Link-layer reachability record isn't present for this * ARP entry; pretend it's reachable and use it as is. */ return (1); } else if (ifnet_llreach_reachable(lr)) { /* * Record is present, it's not shared with other ARP * entries and a packet has recently been received * from the remote host; consider it reachable. */ if (lr->lr_reqcnt == 1) return (1); /* Prime it up, if this is the first time */ if (la->la_lastused == 0) { VERIFY(la->la_llreach != NULL); arp_llreach_use(la); } /* * Record is present and shared with one or more ARP * entries, and a packet has recently been received * from the remote host. Since it's shared by more * than one IP addresses, we can't rely on the link- * layer reachability alone; consider it reachable if * this ARP entry has been used "recently." */ if (ifnet_llreach_reachable_delta(lr, la->la_lastused)) return (1); why = "has alias(es) and hasn't been used in a while"; } else { why = "haven't heard from it in a while"; } if (arp_verbose > 1) { char tmp[MAX_IPv4_STR_LEN]; u_int64_t now = net_uptime(); log(LOG_DEBUG, "%s: ARP probe(s) needed for %s; " "%s [lastused %lld, lastrcvd %lld] secs ago\n", if_name(lr->lr_ifp), inet_ntop(AF_INET, &SIN(rt_key(la->la_rt))->sin_addr, tmp, sizeof (tmp)), why, (la->la_lastused ? (int64_t)(now - la->la_lastused) : -1), (lr->lr_lastrcvd ? (int64_t)(now - lr->lr_lastrcvd) : -1)); } return (0); } /* * Obtain a link-layer source cache entry for the sender. * * NOTE: This is currently only for ARP/Ethernet. */ static void arp_llreach_alloc(struct rtentry *rt, struct ifnet *ifp, void *addr, unsigned int alen, boolean_t solicited) { VERIFY(rt->rt_expire == 0 || rt->rt_rmx.rmx_expire != 0); VERIFY(rt->rt_expire != 0 || rt->rt_rmx.rmx_expire == 0); if (arp_llreach_base != 0 && rt->rt_expire != 0 && !(rt->rt_ifp->if_flags & IFF_LOOPBACK) && ifp->if_addrlen == IF_LLREACH_MAXLEN && /* Ethernet */ alen == ifp->if_addrlen) { struct llinfo_arp *la = rt->rt_llinfo; struct if_llreach *lr; const char *why = NULL, *type = ""; /* Become a regular mutex, just in case */ RT_CONVERT_LOCK(rt); if ((lr = la->la_llreach) != NULL) { type = (solicited ? "ARP reply" : "ARP announcement"); /* * If target has changed, create a new record; * otherwise keep existing record. */ IFLR_LOCK(lr); if (bcmp(addr, lr->lr_key.addr, alen) != 0) { IFLR_UNLOCK(lr); /* Purge any link-layer info caching */ VERIFY(rt->rt_llinfo_purge != NULL); rt->rt_llinfo_purge(rt); lr = NULL; why = " for different target HW address; " "using new llreach record"; } else { lr->lr_probes = 0; /* reset probe count */ IFLR_UNLOCK(lr); if (solicited) { why = " for same target HW address; " "keeping existing llreach record"; } } } if (lr == NULL) { lr = la->la_llreach = ifnet_llreach_alloc(ifp, ETHERTYPE_IP, addr, alen, arp_llreach_base); if (lr != NULL) { lr->lr_probes = 0; /* reset probe count */ if (why == NULL) why = "creating new llreach record"; } } /* Bump up retry ceiling to accomodate unicast retries */ if (lr != NULL) la->la_maxtries = arp_maxtries + arp_unicast_lim; if (arp_verbose > 1 && lr != NULL && why != NULL) { char tmp[MAX_IPv4_STR_LEN]; log(LOG_DEBUG, "%s: %s%s for %s\n", if_name(ifp), type, why, inet_ntop(AF_INET, &SIN(rt_key(rt))->sin_addr, tmp, sizeof (tmp))); } } } struct arptf_arg { int draining; uint32_t killed; uint32_t aging; uint32_t sticky; uint32_t found; }; /* * Free an arp entry. */ static void arptfree(struct llinfo_arp *la, void *arg) { struct arptf_arg *ap = arg; struct rtentry *rt = la->la_rt; lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED); /* rnh_lock acquired by caller protects rt from going away */ RT_LOCK(rt); VERIFY(rt->rt_expire == 0 || rt->rt_rmx.rmx_expire != 0); VERIFY(rt->rt_expire != 0 || rt->rt_rmx.rmx_expire == 0); ap->found++; if (rt->rt_expire == 0 || (rt->rt_flags & RTF_STATIC)) { ap->sticky++; /* ARP entry is permanent? */ if (rt->rt_expire == 0) { RT_UNLOCK(rt); return; } } /* ARP entry hasn't expired and we're not draining? */ if (!ap->draining && rt->rt_expire > net_uptime()) { RT_UNLOCK(rt); ap->aging++; return; } if (rt->rt_refcnt > 0) { /* * ARP entry has expired, with outstanding refcnt. * If we're not draining, force ARP query to be * generated next time this entry is used. */ if (!ap->draining) { struct sockaddr_dl *sdl = SDL(rt->rt_gateway); if (sdl != NULL) sdl->sdl_alen = 0; la->la_asked = 0; rt->rt_flags &= ~RTF_REJECT; } RT_UNLOCK(rt); } else if (!(rt->rt_flags & RTF_STATIC)) { /* * ARP entry has no outstanding refcnt, and we're either * draining or it has expired; delete it from the routing * table. Safe to drop rt_lock and use rt_key, since holding * rnh_lock here prevents another thread from calling * rt_setgate() on this route. */ RT_UNLOCK(rt); rtrequest_locked(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); arpstat.timeouts++; ap->killed++; } else { /* ARP entry is static; let it linger */ RT_UNLOCK(rt); } } void in_arpdrain(void *arg) { #pragma unused(arg) struct llinfo_arp *la, *ola; struct arptf_arg farg; if (arp_verbose) log(LOG_DEBUG, "%s: draining ARP entries\n", __func__); lck_mtx_lock(rnh_lock); la = llinfo_arp.lh_first; bzero(&farg, sizeof (farg)); farg.draining = 1; while ((ola = la) != NULL) { la = la->la_le.le_next; arptfree(ola, &farg); } if (arp_verbose) { log(LOG_DEBUG, "%s: found %u, aging %u, sticky %u, killed %u\n", __func__, farg.found, farg.aging, farg.sticky, farg.killed); } lck_mtx_unlock(rnh_lock); } /* * Timeout routine. Age arp_tab entries periodically. */ static void arp_timeout(void *arg) { #pragma unused(arg) struct llinfo_arp *la, *ola; struct timeval atv; struct arptf_arg farg; lck_mtx_lock(rnh_lock); la = llinfo_arp.lh_first; bzero(&farg, sizeof (farg)); while ((ola = la) != NULL) { la = la->la_le.le_next; arptfree(ola, &farg); } if (arp_verbose) { log(LOG_DEBUG, "%s: found %u, aging %u, sticky %u, killed %u\n", __func__, farg.found, farg.aging, farg.sticky, farg.killed); } atv.tv_usec = 0; atv.tv_sec = arpt_prune; /* re-arm the timer if there's work to do */ arp_timeout_run = 0; if (farg.aging > 0) arp_sched_timeout(&atv); else if (arp_verbose) log(LOG_DEBUG, "%s: not rescheduling timer\n", __func__); lck_mtx_unlock(rnh_lock); } static void arp_sched_timeout(struct timeval *atv) { lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED); if (!arp_timeout_run) { struct timeval tv; if (atv == NULL) { tv.tv_usec = 0; tv.tv_sec = MAX(arpt_prune / 5, 1); atv = &tv; } if (arp_verbose) { log(LOG_DEBUG, "%s: timer scheduled in " "T+%llus.%lluu\n", __func__, (uint64_t)atv->tv_sec, (uint64_t)atv->tv_usec); } arp_timeout_run = 1; timeout(arp_timeout, NULL, tvtohz(atv)); } } /* * ifa_rtrequest() callback */ static void arp_rtrequest(int req, struct rtentry *rt, struct sockaddr *sa) { #pragma unused(sa) struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = rt->rt_llinfo; static struct sockaddr_dl null_sdl = { .sdl_len = sizeof (null_sdl), .sdl_family = AF_LINK }; uint64_t timenow; char buf[MAX_IPv4_STR_LEN]; VERIFY(arpinit_done); lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED); RT_LOCK_ASSERT_HELD(rt); if (rt->rt_flags & RTF_GATEWAY) return; timenow = net_uptime(); 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) && rt_mask(rt) != NULL && SIN(rt_mask(rt))->sin_addr.s_addr != INADDR_BROADCAST) rt->rt_flags |= RTF_CLONING; if (rt->rt_flags & RTF_CLONING) { /* * Case 1: This route should come from a route to iface. */ if (rt_setgate(rt, rt_key(rt), SA(&null_sdl)) == 0) { gate = rt->rt_gateway; SDL(gate)->sdl_type = rt->rt_ifp->if_type; SDL(gate)->sdl_index = rt->rt_ifp->if_index; /* * In case we're called before 1.0 sec. * has elapsed. */ rt_setexpire(rt, MAX(timenow, 1)); } break; } /* Announce a new entry if requested. */ if (rt->rt_flags & RTF_ANNOUNCE) { if (la != NULL) arp_llreach_use(la); /* Mark use timestamp */ RT_UNLOCK(rt); dlil_send_arp(rt->rt_ifp, ARPOP_REQUEST, SDL(gate), rt_key(rt), NULL, rt_key(rt), 0); RT_LOCK(rt); arpstat.txannounces++; } /* FALLTHRU */ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof (null_sdl)) { arpstat.invalidreqs++; log(LOG_ERR, "%s: route to %s has bad gateway address " "(sa_family %u sa_len %u) on %s\n", __func__, inet_ntop(AF_INET, &SIN(rt_key(rt))->sin_addr.s_addr, buf, sizeof (buf)), gate->sa_family, gate->sa_len, if_name(rt->rt_ifp)); break; } SDL(gate)->sdl_type = rt->rt_ifp->if_type; SDL(gate)->sdl_index = rt->rt_ifp->if_index; if (la != NULL) break; /* This happens on a route change */ /* * Case 2: This route may come from cloning, or a manual route * add with a LL address. */ rt->rt_llinfo = la = arp_llinfo_alloc(M_WAITOK); if (la == NULL) { arpstat.reqnobufs++; break; } rt->rt_llinfo_get_ri = arp_llinfo_get_ri; rt->rt_llinfo_get_iflri = arp_llinfo_get_iflri; rt->rt_llinfo_purge = arp_llinfo_purge; rt->rt_llinfo_free = arp_llinfo_free; rt->rt_flags |= RTF_LLINFO; la->la_rt = rt; LIST_INSERT_HEAD(&llinfo_arp, la, la_le); arpstat.inuse++; /* We have at least one entry; arm the timer if not already */ arp_sched_timeout(NULL); /* * This keeps the multicast addresses from showing up * in `arp -a' listings as unresolved. It's not actually * functional. Then the same for broadcast. For IPv4 * link-local address, keep the entry around even after * it has expired. */ if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { RT_UNLOCK(rt); dlil_resolve_multi(rt->rt_ifp, rt_key(rt), gate, sizeof (struct sockaddr_dl)); RT_LOCK(rt); rt_setexpire(rt, 0); } else if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { struct sockaddr_dl *gate_ll = SDL(gate); size_t broadcast_len; ifnet_llbroadcast_copy_bytes(rt->rt_ifp, LLADDR(gate_ll), sizeof (gate_ll->sdl_data), &broadcast_len); gate_ll->sdl_alen = broadcast_len; gate_ll->sdl_family = AF_LINK; gate_ll->sdl_len = sizeof (struct sockaddr_dl); /* In case we're called before 1.0 sec. has elapsed */ rt_setexpire(rt, MAX(timenow, 1)); } else if (IN_LINKLOCAL(ntohl(SIN(rt_key(rt))-> sin_addr.s_addr))) { rt->rt_flags |= RTF_STATIC; } /* Set default maximum number of retries */ la->la_maxtries = arp_maxtries; /* Become a regular mutex, just in case */ RT_CONVERT_LOCK(rt); IFA_LOCK_SPIN(rt->rt_ifa); if (SIN(rt_key(rt))->sin_addr.s_addr == (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { IFA_UNLOCK(rt->rt_ifa); /* * This test used to be * if (loif.if_flags & IFF_UP) * It allowed local traffic to be forced through the * hardware by configuring the loopback down. However, * it causes problems during network configuration * for boards that can't receive packets they send. * It is now necessary to clear "useloopback" and * remove the route to force traffic out to the * hardware. */ rt_setexpire(rt, 0); ifnet_lladdr_copy_bytes(rt->rt_ifp, LLADDR(SDL(gate)), SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); if (useloopback) { if (rt->rt_ifp != lo_ifp) { /* * Purge any link-layer info caching. */ if (rt->rt_llinfo_purge != NULL) rt->rt_llinfo_purge(rt); /* * Adjust route ref count for the * interfaces. */ if (rt->rt_if_ref_fn != NULL) { rt->rt_if_ref_fn(lo_ifp, 1); rt->rt_if_ref_fn(rt->rt_ifp, -1); } } rt->rt_ifp = lo_ifp; /* * If rmx_mtu is not locked, update it * to the MTU used by the new interface. */ if (!(rt->rt_rmx.rmx_locks & RTV_MTU)) rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu; } } else { IFA_UNLOCK(rt->rt_ifa); } break; case RTM_DELETE: if (la == NULL) break; /* * Unchain it but defer the actual freeing until the route * itself is to be freed. rt->rt_llinfo still points to * llinfo_arp, and likewise, la->la_rt still points to this * route entry, except that RTF_LLINFO is now cleared. */ LIST_REMOVE(la, la_le); la->la_le.le_next = NULL; la->la_le.le_prev = NULL; arpstat.inuse--; /* * Purge any link-layer info caching. */ if (rt->rt_llinfo_purge != NULL) rt->rt_llinfo_purge(rt); rt->rt_flags &= ~RTF_LLINFO; if (la->la_hold != NULL) { m_freem(la->la_hold); la->la_hold = NULL; arpstat.purged++; } } } /* * convert hardware address to hex string for logging errors. */ static const char * sdl_addr_to_hex(const struct sockaddr_dl *sdl, char *orig_buf, int buflen) { char *buf = orig_buf; int i; const u_char *lladdr = (u_char *)(size_t)sdl->sdl_data; int maxbytes = buflen / 3; if (maxbytes > sdl->sdl_alen) { maxbytes = sdl->sdl_alen; } *buf = '\0'; for (i = 0; i < maxbytes; i++) { snprintf(buf, 3, "%02x", lladdr[i]); buf += 2; *buf = (i == maxbytes - 1) ? '\0' : ':'; buf++; } return (orig_buf); } /* * arp_lookup_route will lookup the route for a given address. * * The address must be for a host on a local network on this interface. * If the returned route is non-NULL, the route is locked and the caller * is responsible for unlocking it and releasing its reference. */ static errno_t arp_lookup_route(const struct in_addr *addr, int create, int proxy, route_t *route, unsigned int ifscope) { struct sockaddr_inarp sin = { sizeof (sin), AF_INET, 0, { 0 }, { 0 }, 0, 0 }; const char *why = NULL; errno_t error = 0; route_t rt; *route = NULL; sin.sin_addr.s_addr = addr->s_addr; sin.sin_other = proxy ? SIN_PROXY : 0; /* * If the destination is a link-local address, don't * constrain the lookup (don't scope it). */ if (IN_LINKLOCAL(ntohl(addr->s_addr))) ifscope = IFSCOPE_NONE; rt = rtalloc1_scoped((struct sockaddr *)&sin, create, 0, ifscope); if (rt == NULL) return (ENETUNREACH); RT_LOCK(rt); if (rt->rt_flags & RTF_GATEWAY) { why = "host is not on local network"; error = ENETUNREACH; } else if (!(rt->rt_flags & RTF_LLINFO)) { why = "could not allocate llinfo"; error = ENOMEM; } else if (rt->rt_gateway->sa_family != AF_LINK) { why = "gateway route is not ours"; error = EPROTONOSUPPORT; } if (error != 0) { if (create && (arp_verbose || log_arp_warnings)) { char tmp[MAX_IPv4_STR_LEN]; log(LOG_DEBUG, "%s: link#%d %s failed: %s\n", __func__, ifscope, inet_ntop(AF_INET, addr, tmp, sizeof (tmp)), why); } /* * If there are no references to this route, and it is * a cloned route, and not static, and ARP had created * the route, then purge it from the routing table as * it is probably bogus. */ if (rt->rt_refcnt == 1 && (rt->rt_flags & (RTF_WASCLONED | RTF_STATIC)) == RTF_WASCLONED) { /* * Prevent another thread from modiying rt_key, * rt_gateway via rt_setgate() after rt_lock is * dropped by marking the route as defunct. */ rt->rt_flags |= RTF_CONDEMNED; RT_UNLOCK(rt); rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); rtfree(rt); } else { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); } return (error); } /* * Caller releases reference and does RT_UNLOCK(rt). */ *route = rt; return (0); } /* * This is the ARP pre-output routine; care must be taken to ensure that * the "hint" route never gets freed via rtfree(), since the caller may * have stored it inside a struct route with a reference held for that * placeholder. */ errno_t arp_lookup_ip(ifnet_t ifp, const struct sockaddr_in *net_dest, struct sockaddr_dl *ll_dest, size_t ll_dest_len, route_t hint, mbuf_t packet) { route_t route = NULL; /* output route */ errno_t result = 0; struct sockaddr_dl *gateway; struct llinfo_arp *llinfo = NULL; uint64_t timenow; int unreachable = 0; struct if_llreach *lr; struct ifaddr *rt_ifa; struct sockaddr *sa; uint32_t rtflags; struct sockaddr_dl sdl; if (net_dest->sin_family != AF_INET) return (EAFNOSUPPORT); if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) return (ENETDOWN); /* * If we were given a route, verify the route and grab the gateway */ if (hint != NULL) { /* * Callee holds a reference on the route and returns * with the route entry locked, upon success. */ result = route_to_gwroute((const struct sockaddr *) net_dest, hint, &route); if (result != 0) return (result); if (route != NULL) RT_LOCK_ASSERT_HELD(route); } if (packet->m_flags & M_BCAST) { size_t broadcast_len; bzero(ll_dest, ll_dest_len); result = ifnet_llbroadcast_copy_bytes(ifp, LLADDR(ll_dest), ll_dest_len - offsetof(struct sockaddr_dl, sdl_data), &broadcast_len); if (result == 0) { ll_dest->sdl_alen = broadcast_len; ll_dest->sdl_family = AF_LINK; ll_dest->sdl_len = sizeof (struct sockaddr_dl); } goto release; } if (packet->m_flags & M_MCAST) { if (route != NULL) RT_UNLOCK(route); result = dlil_resolve_multi(ifp, (const struct sockaddr *)net_dest, (struct sockaddr *)ll_dest, ll_dest_len); if (route != NULL) RT_LOCK(route); goto release; } /* * If we didn't find a route, or the route doesn't have * link layer information, trigger the creation of the * route and link layer information. */ if (route == NULL || route->rt_llinfo == NULL) { /* Clean up now while we can */ if (route != NULL) { if (route == hint) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); } else { RT_UNLOCK(route); rtfree(route); } } /* * Callee holds a reference on the route and returns * with the route entry locked, upon success. */ result = arp_lookup_route(&net_dest->sin_addr, 1, 0, &route, ifp->if_index); if (result == 0) RT_LOCK_ASSERT_HELD(route); } if (result || route == NULL || (llinfo = route->rt_llinfo) == NULL) { /* In case result is 0 but no route, return an error */ if (result == 0) result = EHOSTUNREACH; if (route != NULL && route->rt_llinfo == NULL) { char tmp[MAX_IPv4_STR_LEN]; log(LOG_ERR, "%s: can't allocate llinfo for %s\n", __func__, inet_ntop(AF_INET, &net_dest->sin_addr, tmp, sizeof (tmp))); } goto release; } /* * Now that we have the right route, is it filled in? */ gateway = SDL(route->rt_gateway); timenow = net_uptime(); VERIFY(route->rt_expire == 0 || route->rt_rmx.rmx_expire != 0); VERIFY(route->rt_expire != 0 || route->rt_rmx.rmx_expire == 0); if ((route->rt_expire == 0 || route->rt_expire > timenow) && gateway != NULL && gateway->sdl_family == AF_LINK && gateway->sdl_alen != 0 && !(unreachable = !arp_llreach_reachable(llinfo))) { bcopy(gateway, ll_dest, MIN(gateway->sdl_len, ll_dest_len)); result = 0; arp_llreach_use(llinfo); /* Mark use timestamp */ /* * Start the unicast probe right before the entry expires. */ lr = llinfo->la_llreach; if (lr == NULL) goto release; rt_ifa = route->rt_ifa; /* Become a regular mutex, just in case */ RT_CONVERT_LOCK(route); IFLR_LOCK_SPIN(lr); if (route->rt_expire <= timenow + arp_unicast_lim && ifp->if_addrlen == IF_LLREACH_MAXLEN && lr->lr_probes <= arp_unicast_lim) { lr->lr_probes++; bzero(&sdl, sizeof (sdl)); sdl.sdl_alen = ifp->if_addrlen; bcopy(&lr->lr_key.addr, LLADDR(&sdl), ifp->if_addrlen); IFLR_UNLOCK(lr); IFA_LOCK_SPIN(rt_ifa); IFA_ADDREF_LOCKED(rt_ifa); sa = rt_ifa->ifa_addr; IFA_UNLOCK(rt_ifa); rtflags = route->rt_flags; RT_UNLOCK(route); dlil_send_arp(ifp, ARPOP_REQUEST, NULL, sa, (const struct sockaddr_dl *)&sdl, (const struct sockaddr *)net_dest, rtflags); IFA_REMREF(rt_ifa); RT_LOCK(route); } else IFLR_UNLOCK(lr); goto release; } else if (unreachable) { /* * Discard existing answer in case we need to probe. */ gateway->sdl_alen = 0; } if (ifp->if_flags & IFF_NOARP) { result = ENOTSUP; goto release; } /* * Route wasn't complete/valid. We need to arp. */ if (packet != NULL) { if (llinfo->la_hold != NULL) { m_freem(llinfo->la_hold); arpstat.dropped++; } llinfo->la_hold = packet; } if (route->rt_expire) { route->rt_flags &= ~RTF_REJECT; if (llinfo->la_asked == 0 || route->rt_expire != timenow) { rt_setexpire(route, timenow); if (llinfo->la_asked++ < llinfo->la_maxtries) { struct kev_msg ev_msg; struct kev_in_arpfailure in_arpfailure; boolean_t sendkev = FALSE; rt_ifa = route->rt_ifa; lr = llinfo->la_llreach; /* Become a regular mutex, just in case */ RT_CONVERT_LOCK(route); /* Update probe count, if applicable */ if (lr != NULL) { IFLR_LOCK_SPIN(lr); lr->lr_probes++; IFLR_UNLOCK(lr); } if (ifp->if_addrlen == IF_LLREACH_MAXLEN && route->rt_flags & RTF_ROUTER && llinfo->la_asked > 1) { sendkev = TRUE; llinfo->la_flags |= LLINFO_RTRFAIL_EVTSENT; } IFA_LOCK_SPIN(rt_ifa); IFA_ADDREF_LOCKED(rt_ifa); sa = rt_ifa->ifa_addr; IFA_UNLOCK(rt_ifa); arp_llreach_use(llinfo); /* Mark use tstamp */ rtflags = route->rt_flags; RT_UNLOCK(route); dlil_send_arp(ifp, ARPOP_REQUEST, NULL, sa, NULL, (const struct sockaddr *)net_dest, rtflags); IFA_REMREF(rt_ifa); if (sendkev) { bzero(&ev_msg, sizeof(ev_msg)); bzero(&in_arpfailure, sizeof(in_arpfailure)); in_arpfailure.link_data.if_family = ifp->if_family; in_arpfailure.link_data.if_unit = ifp->if_unit; strlcpy(in_arpfailure.link_data.if_name, ifp->if_name, IFNAMSIZ); ev_msg.vendor_code = KEV_VENDOR_APPLE; ev_msg.kev_class = KEV_NETWORK_CLASS; ev_msg.kev_subclass = KEV_INET_SUBCLASS; ev_msg.event_code = KEV_INET_ARPRTRFAILURE; ev_msg.dv[0].data_ptr = &in_arpfailure; ev_msg.dv[0].data_length = sizeof(struct kev_in_arpfailure); kev_post_msg(&ev_msg); } result = EJUSTRETURN; RT_LOCK(route); goto release; } else { route->rt_flags |= RTF_REJECT; rt_setexpire(route, route->rt_expire + arpt_down); llinfo->la_asked = 0; /* * Clear la_hold; don't free the packet since * we're not returning EJUSTRETURN; the caller * will handle the freeing. */ llinfo->la_hold = NULL; result = EHOSTUNREACH; goto release; } } } /* The packet is now held inside la_hold (can "packet" be NULL?) */ result = EJUSTRETURN; release: if (result == EHOSTUNREACH) arpstat.dropped++; if (route != NULL) { if (route == hint) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); } else { RT_UNLOCK(route); rtfree(route); } } return (result); } errno_t arp_ip_handle_input(ifnet_t ifp, u_short arpop, const struct sockaddr_dl *sender_hw, const struct sockaddr_in *sender_ip, const struct sockaddr_in *target_ip) { char ipv4str[MAX_IPv4_STR_LEN]; struct sockaddr_dl proxied; struct sockaddr_dl *gateway, *target_hw = NULL; struct ifaddr *ifa; struct in_ifaddr *ia; struct in_ifaddr *best_ia = NULL; struct sockaddr_in best_ia_sin; route_t route = NULL; char buf[3 * MAX_HW_LEN]; /* enough for MAX_HW_LEN byte hw address */ struct llinfo_arp *llinfo; errno_t error; int created_announcement = 0; int bridged = 0, is_bridge = 0; arpstat.received++; /* Do not respond to requests for 0.0.0.0 */ if (target_ip->sin_addr.s_addr == INADDR_ANY && arpop == ARPOP_REQUEST) goto done; if (ifp->if_bridge) bridged = 1; if (ifp->if_type == IFT_BRIDGE) is_bridge = 1; if (arpop == ARPOP_REPLY) arpstat.rxreplies++; /* * Determine if this ARP is for us * For a bridge, we want to check the address irrespective * of the receive interface. */ lck_rw_lock_shared(in_ifaddr_rwlock); TAILQ_FOREACH(ia, INADDR_HASH(target_ip->sin_addr.s_addr), ia_hash) { IFA_LOCK_SPIN(&ia->ia_ifa); if (((bridged && ia->ia_ifp->if_bridge != NULL) || (ia->ia_ifp == ifp)) && ia->ia_addr.sin_addr.s_addr == target_ip->sin_addr.s_addr) { best_ia = ia; best_ia_sin = best_ia->ia_addr; IFA_ADDREF_LOCKED(&ia->ia_ifa); IFA_UNLOCK(&ia->ia_ifa); lck_rw_done(in_ifaddr_rwlock); goto match; } IFA_UNLOCK(&ia->ia_ifa); } TAILQ_FOREACH(ia, INADDR_HASH(sender_ip->sin_addr.s_addr), ia_hash) { IFA_LOCK_SPIN(&ia->ia_ifa); if (((bridged && ia->ia_ifp->if_bridge != NULL) || (ia->ia_ifp == ifp)) && ia->ia_addr.sin_addr.s_addr == sender_ip->sin_addr.s_addr) { best_ia = ia; best_ia_sin = best_ia->ia_addr; IFA_ADDREF_LOCKED(&ia->ia_ifa); IFA_UNLOCK(&ia->ia_ifa); lck_rw_done(in_ifaddr_rwlock); goto match; } IFA_UNLOCK(&ia->ia_ifa); } #define BDG_MEMBER_MATCHES_ARP(addr, ifp, ia) \ (ia->ia_ifp->if_bridge == ifp->if_softc && \ bcmp(IF_LLADDR(ia->ia_ifp), IF_LLADDR(ifp), ifp->if_addrlen) == 0 && \ addr == ia->ia_addr.sin_addr.s_addr) /* * Check the case when bridge shares its MAC address with * some of its children, so packets are claimed by bridge * itself (bridge_input() does it first), but they are really * meant to be destined to the bridge member. */ if (is_bridge) { TAILQ_FOREACH(ia, INADDR_HASH(target_ip->sin_addr.s_addr), ia_hash) { IFA_LOCK_SPIN(&ia->ia_ifa); if (BDG_MEMBER_MATCHES_ARP(target_ip->sin_addr.s_addr, ifp, ia)) { ifp = ia->ia_ifp; best_ia = ia; best_ia_sin = best_ia->ia_addr; IFA_ADDREF_LOCKED(&ia->ia_ifa); IFA_UNLOCK(&ia->ia_ifa); lck_rw_done(in_ifaddr_rwlock); goto match; } IFA_UNLOCK(&ia->ia_ifa); } } #undef BDG_MEMBER_MATCHES_ARP lck_rw_done(in_ifaddr_rwlock); /* * No match, use the first inet address on the receive interface * as a dummy address for the rest of the function; we may be * proxying for another address. */ ifnet_lock_shared(ifp); TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) { IFA_LOCK_SPIN(ifa); if (ifa->ifa_addr->sa_family != AF_INET) { IFA_UNLOCK(ifa); continue; } best_ia = (struct in_ifaddr *)ifa; best_ia_sin = best_ia->ia_addr; IFA_ADDREF_LOCKED(ifa); IFA_UNLOCK(ifa); ifnet_lock_done(ifp); goto match; } ifnet_lock_done(ifp); /* * If we're not a bridge member, or if we are but there's no * IPv4 address to use for the interface, drop the packet. */ if (!bridged || best_ia == NULL) goto done; match: /* If the packet is from this interface, ignore the packet */ if (bcmp(CONST_LLADDR(sender_hw), IF_LLADDR(ifp), sender_hw->sdl_alen) == 0) goto done; /* Check for a conflict */ if (!bridged && sender_ip->sin_addr.s_addr == best_ia_sin.sin_addr.s_addr) { struct kev_msg ev_msg; struct kev_in_collision *in_collision; u_char storage[sizeof (struct kev_in_collision) + MAX_HW_LEN]; bzero(&ev_msg, sizeof (struct kev_msg)); bzero(storage, (sizeof (struct kev_in_collision) + MAX_HW_LEN)); in_collision = (struct kev_in_collision *)(void *)storage; log(LOG_ERR, "%s duplicate IP address %s sent from " "address %s\n", if_name(ifp), inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof (ipv4str)), sdl_addr_to_hex(sender_hw, buf, sizeof (buf))); /* Send a kernel event so anyone can learn of the conflict */ in_collision->link_data.if_family = ifp->if_family; in_collision->link_data.if_unit = ifp->if_unit; strlcpy(&in_collision->link_data.if_name[0], ifp->if_name, IFNAMSIZ); in_collision->ia_ipaddr = sender_ip->sin_addr; in_collision->hw_len = (sender_hw->sdl_alen < MAX_HW_LEN) ? sender_hw->sdl_alen : MAX_HW_LEN; bcopy(CONST_LLADDR(sender_hw), (caddr_t)in_collision->hw_addr, in_collision->hw_len); ev_msg.vendor_code = KEV_VENDOR_APPLE; ev_msg.kev_class = KEV_NETWORK_CLASS; ev_msg.kev_subclass = KEV_INET_SUBCLASS; ev_msg.event_code = KEV_INET_ARPCOLLISION; ev_msg.dv[0].data_ptr = in_collision; ev_msg.dv[0].data_length = sizeof (struct kev_in_collision) + in_collision->hw_len; ev_msg.dv[1].data_length = 0; kev_post_msg(&ev_msg); arpstat.dupips++; goto respond; } /* * Look up the routing entry. If it doesn't exist and we are the * target, and the sender isn't 0.0.0.0, go ahead and create one. * Callee holds a reference on the route and returns with the route * entry locked, upon success. */ error = arp_lookup_route(&sender_ip->sin_addr, (target_ip->sin_addr.s_addr == best_ia_sin.sin_addr.s_addr && sender_ip->sin_addr.s_addr != 0), 0, &route, ifp->if_index); if (error == 0) RT_LOCK_ASSERT_HELD(route); if (error || route == NULL || route->rt_gateway == NULL) { if (arpop != ARPOP_REQUEST) goto respond; if (arp_sendllconflict && send_conflicting_probes != 0 && (ifp->if_eflags & IFEF_ARPLL) && IN_LINKLOCAL(ntohl(target_ip->sin_addr.s_addr)) && sender_ip->sin_addr.s_addr == INADDR_ANY) { /* * Verify this ARP probe doesn't conflict with * an IPv4LL we know of on another interface. */ if (route != NULL) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; } /* * Callee holds a reference on the route and returns * with the route entry locked, upon success. */ error = arp_lookup_route(&target_ip->sin_addr, 0, 0, &route, ifp->if_index); if (error != 0 || route == NULL || route->rt_gateway == NULL) goto respond; RT_LOCK_ASSERT_HELD(route); gateway = SDL(route->rt_gateway); if (route->rt_ifp != ifp && gateway->sdl_alen != 0 && (gateway->sdl_alen != sender_hw->sdl_alen || bcmp(CONST_LLADDR(gateway), CONST_LLADDR(sender_hw), gateway->sdl_alen) != 0)) { /* * A node is probing for an IPv4LL we know * exists on a different interface. We respond * with a conflicting probe to force the new * device to pick a different IPv4LL address. */ if (arp_verbose || log_arp_warnings) { log(LOG_INFO, "arp: %s on %s sent " "probe for %s, already on %s\n", sdl_addr_to_hex(sender_hw, buf, sizeof (buf)), if_name(ifp), inet_ntop(AF_INET, &target_ip->sin_addr, ipv4str, sizeof (ipv4str)), if_name(route->rt_ifp)); log(LOG_INFO, "arp: sending " "conflicting probe to %s on %s\n", sdl_addr_to_hex(sender_hw, buf, sizeof (buf)), if_name(ifp)); } /* Mark use timestamp */ if (route->rt_llinfo != NULL) arp_llreach_use(route->rt_llinfo); /* We're done with the route */ RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; /* * Send a conservative unicast "ARP probe". * This should force the other device to pick * a new number. This will not force the * device to pick a new number if the device * has already assigned that number. This will * not imply to the device that we own that * address. The link address is always * present; it's never freed. */ ifnet_lock_shared(ifp); ifa = ifp->if_lladdr; IFA_ADDREF(ifa); ifnet_lock_done(ifp); dlil_send_arp_internal(ifp, ARPOP_REQUEST, SDL(ifa->ifa_addr), (const struct sockaddr *)sender_ip, sender_hw, (const struct sockaddr *)target_ip); IFA_REMREF(ifa); ifa = NULL; arpstat.txconflicts++; } goto respond; } else if (keep_announcements != 0 && target_ip->sin_addr.s_addr == sender_ip->sin_addr.s_addr) { /* * Don't create entry if link-local address and * link-local is disabled */ if (!IN_LINKLOCAL(ntohl(sender_ip->sin_addr.s_addr)) || (ifp->if_eflags & IFEF_ARPLL)) { if (route != NULL) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; } /* * Callee holds a reference on the route and * returns with the route entry locked, upon * success. */ error = arp_lookup_route(&sender_ip->sin_addr, 1, 0, &route, ifp->if_index); if (error == 0) RT_LOCK_ASSERT_HELD(route); if (error == 0 && route != NULL && route->rt_gateway != NULL) created_announcement = 1; } if (created_announcement == 0) goto respond; } else { goto respond; } } RT_LOCK_ASSERT_HELD(route); VERIFY(route->rt_expire == 0 || route->rt_rmx.rmx_expire != 0); VERIFY(route->rt_expire != 0 || route->rt_rmx.rmx_expire == 0); gateway = SDL(route->rt_gateway); if (!bridged && route->rt_ifp != ifp) { if (!IN_LINKLOCAL(ntohl(sender_ip->sin_addr.s_addr)) || !(ifp->if_eflags & IFEF_ARPLL)) { if (arp_verbose || log_arp_warnings) log(LOG_ERR, "arp: %s is on %s but got " "reply from %s on %s\n", inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof (ipv4str)), if_name(route->rt_ifp), sdl_addr_to_hex(sender_hw, buf, sizeof (buf)), if_name(ifp)); goto respond; } else { /* Don't change a permanent address */ if (route->rt_expire == 0) goto respond; /* * We're about to check and/or change the route's ifp * and ifa, so do the lock dance: drop rt_lock, hold * rnh_lock and re-hold rt_lock to avoid violating the * lock ordering. We have an extra reference on the * route, so it won't go away while we do this. */ RT_UNLOCK(route); lck_mtx_lock(rnh_lock); RT_LOCK(route); /* * Don't change the cloned route away from the * parent's interface if the address did resolve * or if the route is defunct. rt_ifp on both * the parent and the clone can now be freely * accessed now that we have acquired rnh_lock. */ gateway = SDL(route->rt_gateway); if ((gateway->sdl_alen != 0 && route->rt_parent != NULL && route->rt_parent->rt_ifp == route->rt_ifp) || (route->rt_flags & RTF_CONDEMNED)) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; lck_mtx_unlock(rnh_lock); goto respond; } if (route->rt_ifp != ifp) { /* * Purge any link-layer info caching. */ if (route->rt_llinfo_purge != NULL) route->rt_llinfo_purge(route); /* Adjust route ref count for the interfaces */ if (route->rt_if_ref_fn != NULL) { route->rt_if_ref_fn(ifp, 1); route->rt_if_ref_fn(route->rt_ifp, -1); } } /* Change the interface when the existing route is on */ route->rt_ifp = ifp; /* * If rmx_mtu is not locked, update it * to the MTU used by the new interface. */ if (!(route->rt_rmx.rmx_locks & RTV_MTU)) route->rt_rmx.rmx_mtu = route->rt_ifp->if_mtu; rtsetifa(route, &best_ia->ia_ifa); gateway->sdl_index = ifp->if_index; RT_UNLOCK(route); lck_mtx_unlock(rnh_lock); RT_LOCK(route); /* Don't bother if the route is down */ if (!(route->rt_flags & RTF_UP)) goto respond; /* Refresh gateway pointer */ gateway = SDL(route->rt_gateway); } RT_LOCK_ASSERT_HELD(route); } if (gateway->sdl_alen != 0 && bcmp(LLADDR(gateway), CONST_LLADDR(sender_hw), gateway->sdl_alen) != 0) { if (route->rt_expire != 0 && (arp_verbose || log_arp_warnings)) { char buf2[3 * MAX_HW_LEN]; log(LOG_INFO, "arp: %s moved from %s to %s on %s\n", inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof (ipv4str)), sdl_addr_to_hex(gateway, buf, sizeof (buf)), sdl_addr_to_hex(sender_hw, buf2, sizeof (buf2)), if_name(ifp)); } else if (route->rt_expire == 0) { if (arp_verbose || log_arp_warnings) { log(LOG_ERR, "arp: %s attempts to modify " "permanent entry for %s on %s\n", sdl_addr_to_hex(sender_hw, buf, sizeof (buf)), inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof (ipv4str)), if_name(ifp)); } goto respond; } } /* Copy the sender hardware address in to the route's gateway address */ gateway->sdl_alen = sender_hw->sdl_alen; bcopy(CONST_LLADDR(sender_hw), LLADDR(gateway), gateway->sdl_alen); /* Update the expire time for the route and clear the reject flag */ if (route->rt_expire != 0) rt_setexpire(route, net_uptime() + arpt_keep); route->rt_flags &= ~RTF_REJECT; /* cache the gateway (sender HW) address */ arp_llreach_alloc(route, ifp, LLADDR(gateway), gateway->sdl_alen, (arpop == ARPOP_REPLY)); llinfo = route->rt_llinfo; /* send a notification that the route is back up */ if (ifp->if_addrlen == IF_LLREACH_MAXLEN && route->rt_flags & RTF_ROUTER && llinfo->la_flags & LLINFO_RTRFAIL_EVTSENT) { struct kev_msg ev_msg; struct kev_in_arpfailure in_arpalive; llinfo->la_flags &= ~LLINFO_RTRFAIL_EVTSENT; RT_UNLOCK(route); bzero(&ev_msg, sizeof(ev_msg)); bzero(&in_arpalive, sizeof(in_arpalive)); in_arpalive.link_data.if_family = ifp->if_family; in_arpalive.link_data.if_unit = ifp->if_unit; strlcpy(in_arpalive.link_data.if_name, ifp->if_name, IFNAMSIZ); ev_msg.vendor_code = KEV_VENDOR_APPLE; ev_msg.kev_class = KEV_NETWORK_CLASS; ev_msg.kev_subclass = KEV_INET_SUBCLASS; ev_msg.event_code = KEV_INET_ARPRTRALIVE; ev_msg.dv[0].data_ptr = &in_arpalive; ev_msg.dv[0].data_length = sizeof(struct kev_in_arpalive); kev_post_msg(&ev_msg); RT_LOCK(route); } /* update the llinfo, send a queued packet if there is one */ llinfo->la_asked = 0; if (llinfo->la_hold) { struct mbuf *m0 = llinfo->la_hold; llinfo->la_hold = NULL; RT_UNLOCK(route); dlil_output(ifp, PF_INET, m0, (caddr_t)route, rt_key(route), 0, NULL); RT_REMREF(route); route = NULL; } respond: if (route != NULL) { /* Mark use timestamp if we're going to send a reply */ if (arpop == ARPOP_REQUEST && route->rt_llinfo != NULL) arp_llreach_use(route->rt_llinfo); RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; } if (arpop != ARPOP_REQUEST) goto done; arpstat.rxrequests++; /* If we are not the target, check if we should proxy */ if (target_ip->sin_addr.s_addr != best_ia_sin.sin_addr.s_addr) { /* * Find a proxy route; callee holds a reference on the * route and returns with the route entry locked, upon * success. */ error = arp_lookup_route(&target_ip->sin_addr, 0, SIN_PROXY, &route, ifp->if_index); if (error == 0) { RT_LOCK_ASSERT_HELD(route); /* * Return proxied ARP replies only on the interface * or bridge cluster where this network resides. * Otherwise we may conflict with the host we are * proxying for. */ if (route->rt_ifp != ifp && (route->rt_ifp->if_bridge != ifp->if_bridge || ifp->if_bridge == NULL)) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); goto done; } proxied = *SDL(route->rt_gateway); target_hw = &proxied; } else { /* * We don't have a route entry indicating we should * use proxy. If we aren't supposed to proxy all, * we are done. */ if (!arp_proxyall) goto done; /* * See if we have a route to the target ip before * we proxy it. */ route = rtalloc1_scoped((struct sockaddr *) (size_t)target_ip, 0, 0, ifp->if_index); if (!route) goto done; /* * Don't proxy for hosts already on the same interface. */ RT_LOCK(route); if (route->rt_ifp == ifp) { RT_UNLOCK(route); rtfree(route); goto done; } } /* Mark use timestamp */ if (route->rt_llinfo != NULL) arp_llreach_use(route->rt_llinfo); RT_REMREF_LOCKED(route); RT_UNLOCK(route); } dlil_send_arp(ifp, ARPOP_REPLY, target_hw, (const struct sockaddr *)target_ip, sender_hw, (const struct sockaddr *)sender_ip, 0); done: if (best_ia != NULL) IFA_REMREF(&best_ia->ia_ifa); return (0); } void arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) { struct sockaddr *sa; IFA_LOCK(ifa); ifa->ifa_rtrequest = arp_rtrequest; ifa->ifa_flags |= RTF_CLONING; sa = ifa->ifa_addr; IFA_UNLOCK(ifa); dlil_send_arp(ifp, ARPOP_REQUEST, NULL, sa, NULL, sa, 0); } static int arp_getstat SYSCTL_HANDLER_ARGS { #pragma unused(oidp, arg1, arg2) if (req->oldptr == USER_ADDR_NULL) req->oldlen = (size_t)sizeof (struct arpstat); return (SYSCTL_OUT(req, &arpstat, MIN(sizeof (arpstat), req->oldlen))); }