/* * Copyright (c) 2004-2008 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 #define SA(p) ((struct sockaddr *)(p)) #define SIN(s) ((struct sockaddr_in *)s) #define CONST_LLADDR(s) ((const u_char*)((s)->sdl_data + (s)->sdl_nlen)) #define rt_expire rt_rmx.rmx_expire #define equal(a1, a2) (bcmp((caddr_t)(a1), (caddr_t)(a2), (a1)->sa_len) == 0) static const size_t MAX_HW_LEN = 10; 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 */ static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ static int arpt_down = 20; /* once declared down, don't send for 20 sec */ /* Apple Hardware SUM16 checksuming */ int apple_hwcksum_tx = 1; int apple_hwcksum_rx = 1; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, &arpt_prune, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, &arpt_keep, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, &arpt_down, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, apple_hwcksum_tx, CTLFLAG_RW, &apple_hwcksum_tx, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, apple_hwcksum_rx, CTLFLAG_RW, &apple_hwcksum_rx, 0, ""); 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 */ int32_t la_asked; /* last time we QUERIED for this addr */ }; /* * 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 * * - 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. */ static LIST_HEAD(, llinfo_arp) llinfo_arp; static int arp_inuse, arp_allocated; static int arp_maxtries = 5; static int useloopback = 1; /* use loopback interface for local traffic */ static int arp_proxyall = 0; static int arp_sendllconflict = 0; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, &arp_maxtries, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, &useloopback, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, &arp_proxyall, 0, ""); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, sendllconflict, CTLFLAG_RW, &arp_sendllconflict, 0, ""); static int log_arp_warnings = 0; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_warnings, CTLFLAG_RW, &log_arp_warnings, 0, "log arp warning messages"); static int keep_announcements = 1; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, keep_announcements, CTLFLAG_RW, &keep_announcements, 0, "keep arp announcements"); static int send_conflicting_probes = 1; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, send_conflicting_probes, CTLFLAG_RW, &send_conflicting_probes, 0, "send conflicting link-local arp probes"); static errno_t arp_lookup_route(const struct in_addr *, int, int, route_t *, unsigned int); static void arptimer(void *); static struct llinfo_arp *arp_llinfo_alloc(void); static void arp_llinfo_free(void *); extern u_int32_t ipv4_ll_arp_aware; static int arpinit_done; 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) { if (arpinit_done) { log(LOG_NOTICE, "arp_init called more than once (ignored)\n"); return; } 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); arpinit_done = 1; /* start timer */ timeout(arptimer, (caddr_t)0, hz); } static struct llinfo_arp * arp_llinfo_alloc(void) { return (zalloc(llinfo_arp_zone)); } 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; } zfree(llinfo_arp_zone, la); } /* * Free an arp entry. */ static void arptfree(struct llinfo_arp *la) { struct rtentry *rt = la->la_rt; struct sockaddr_dl *sdl; lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED); RT_LOCK_ASSERT_HELD(rt); 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; RT_UNLOCK(rt); } else { /* * 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); } } /* * Timeout routine. Age arp_tab entries periodically. */ /* ARGSUSED */ static void arptimer(void *ignored_arg) { #pragma unused (ignored_arg) struct llinfo_arp *la, *ola; struct timeval timenow; lck_mtx_lock(rnh_lock); la = llinfo_arp.lh_first; getmicrotime(&timenow); while ((ola = la) != 0) { struct rtentry *rt = la->la_rt; la = la->la_le.le_next; RT_LOCK(rt); if (rt->rt_expire && rt->rt_expire <= timenow.tv_sec) arptfree(ola); /* timer has expired, clear */ else RT_UNLOCK(rt); } lck_mtx_unlock(rnh_lock); timeout(arptimer, (caddr_t)0, arpt_prune * hz); } /* * Parallel to llc_rtrequest. */ static void arp_rtrequest( int req, struct rtentry *rt, __unused struct sockaddr *sa) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = rt->rt_llinfo; static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK, 0, 0, 0, 0, 0, {0}}; struct timeval timenow; if (!arpinit_done) { panic("%s: ARP has not been initialized", __func__); /* NOTREACHED */ } lck_mtx_assert(rnh_lock, LCK_MTX_ASSERT_OWNED); RT_LOCK_ASSERT_HELD(rt); if (rt->rt_flags & RTF_GATEWAY) return; getmicrotime(&timenow); 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 && SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 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), (struct sockaddr *)&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->rt_expire = MAX(timenow.tv_sec, 1); } break; } /* Announce a new entry if requested. */ if (rt->rt_flags & RTF_ANNOUNCE) { RT_UNLOCK(rt); dlil_send_arp(rt->rt_ifp, ARPOP_REQUEST, SDL(gate), rt_key(rt), NULL, rt_key(rt)); RT_LOCK(rt); } /*FALLTHROUGH*/ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof(null_sdl)) { if (log_arp_warnings) log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); break; } SDL(gate)->sdl_type = rt->rt_ifp->if_type; SDL(gate)->sdl_index = rt->rt_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. */ rt->rt_llinfo = la = arp_llinfo_alloc(); if (la == NULL) { if (log_arp_warnings) log(LOG_DEBUG, "%s: malloc failed\n", __func__); break; } rt->rt_llinfo_free = arp_llinfo_free; arp_inuse++, arp_allocated++; Bzero(la, sizeof(*la)); la->la_rt = rt; rt->rt_flags |= RTF_LLINFO; LIST_INSERT_HEAD(&llinfo_arp, la, la_le); /* * This keeps the multicast addresses from showing up * in `arp -a' listings as unresolved. It's not actually * functional. Then the same for broadcast. */ 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->rt_expire = 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->rt_expire = MAX(timenow.tv_sec, 1); } if (SIN(rt_key(rt))->sin_addr.s_addr == (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { /* * 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->rt_expire = 0; ifnet_lladdr_copy_bytes(rt->rt_ifp, LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); if (useloopback) rt->rt_ifp = lo_ifp; } break; case RTM_DELETE: if (la == 0) break; arp_inuse--; /* * 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; rt->rt_flags &= ~RTF_LLINFO; if (la->la_hold != NULL) m_freem(la->la_hold); la->la_hold = NULL; } } /* * 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; 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 && log_arp_warnings) { char tmp[MAX_IPv4_STR_LEN]; log(LOG_DEBUG, "arplookup link#%d %s failed: %s\n", 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, 0); rtfree(rt); } else { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); } return (error); } /* * Caller releases reference and does RT_UNLOCK(rt). */ *route = rt; return (0); } /* * arp_route_to_gateway_route will find the gateway route for a given route. * * If the route is down, look the route up again. * If the route goes through a gateway, get the route to the gateway. * If the gateway route is down, look it up again. * If the route is set to reject, verify it hasn't expired. * * If the returned route is non-NULL, the caller is responsible for * releasing the reference and unlocking the route. */ #define senderr(e) { error = (e); goto bad; } __private_extern__ errno_t arp_route_to_gateway_route(const struct sockaddr *net_dest, route_t hint0, route_t *out_route) { struct timeval timenow; route_t rt = hint0, hint = hint0; errno_t error = 0; *out_route = NULL; /* * Next hop determination. Because we may involve the gateway route * in addition to the original route, locking is rather complicated. * The general concept is that regardless of whether the route points * to the original route or to the gateway route, this routine takes * an extra reference on such a route. This extra reference will be * released at the end. * * Care must be taken to ensure that the "hint0" route never gets freed * via rtfree(), since the caller may have stored it inside a struct * route with a reference held for that placeholder. */ if (rt != NULL) { unsigned int ifindex; RT_LOCK_SPIN(rt); ifindex = rt->rt_ifp->if_index; RT_ADDREF_LOCKED(rt); if (!(rt->rt_flags & RTF_UP)) { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); /* route is down, find a new one */ hint = rt = rtalloc1_scoped((struct sockaddr *) (size_t)net_dest, 1, 0, ifindex); if (hint != NULL) { RT_LOCK_SPIN(rt); ifindex = rt->rt_ifp->if_index; } else { senderr(EHOSTUNREACH); } } /* * We have a reference to "rt" by now; it will either * be released or freed at the end of this routine. */ RT_LOCK_ASSERT_HELD(rt); if (rt->rt_flags & RTF_GATEWAY) { struct rtentry *gwrt = rt->rt_gwroute; struct sockaddr_in gw; /* If there's no gateway rt, look it up */ if (gwrt == NULL) { gw = *((struct sockaddr_in *)rt->rt_gateway); RT_UNLOCK(rt); goto lookup; } /* Become a regular mutex */ RT_CONVERT_LOCK(rt); /* * Take gwrt's lock while holding route's lock; * this is okay since gwrt never points back * to "rt", so no lock ordering issues. */ RT_LOCK_SPIN(gwrt); if (!(gwrt->rt_flags & RTF_UP)) { struct rtentry *ogwrt; rt->rt_gwroute = NULL; RT_UNLOCK(gwrt); gw = *((struct sockaddr_in *)rt->rt_gateway); RT_UNLOCK(rt); rtfree(gwrt); lookup: gwrt = rtalloc1_scoped( (struct sockaddr *)&gw, 1, 0, ifindex); RT_LOCK(rt); /* * Bail out if the route is down, no route * to gateway, circular route, or if the * gateway portion of "rt" has changed. */ if (!(rt->rt_flags & RTF_UP) || gwrt == NULL || gwrt == rt || !equal(SA(&gw), rt->rt_gateway)) { if (gwrt == rt) { RT_REMREF_LOCKED(gwrt); gwrt = NULL; } RT_UNLOCK(rt); if (gwrt != NULL) rtfree(gwrt); senderr(EHOSTUNREACH); } /* Remove any existing gwrt */ ogwrt = rt->rt_gwroute; if ((rt->rt_gwroute = gwrt) != NULL) RT_ADDREF(gwrt); /* Clean up "rt" now while we can */ if (rt == hint0) { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); } else { RT_UNLOCK(rt); rtfree(rt); } rt = gwrt; /* Now free the replaced gwrt */ if (ogwrt != NULL) rtfree(ogwrt); /* If still no route to gateway, bail out */ if (rt == NULL) senderr(EHOSTUNREACH); } else { RT_ADDREF_LOCKED(gwrt); RT_UNLOCK(gwrt); /* Clean up "rt" now while we can */ if (rt == hint0) { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); } else { RT_UNLOCK(rt); rtfree(rt); } rt = gwrt; } /* rt == gwrt; if it is now down, give up */ RT_LOCK_SPIN(rt); if (!(rt->rt_flags & RTF_UP)) { RT_UNLOCK(rt); senderr(EHOSTUNREACH); } } if (rt->rt_flags & RTF_REJECT) { getmicrotime(&timenow); if (rt->rt_rmx.rmx_expire == 0 || timenow.tv_sec < rt->rt_rmx.rmx_expire) { RT_UNLOCK(rt); senderr(rt == hint ? EHOSTDOWN : EHOSTUNREACH); } } /* Become a regular mutex */ RT_CONVERT_LOCK(rt); /* Caller is responsible for cleaning up "rt" */ *out_route = rt; } return (0); bad: /* Clean up route (either it is "rt" or "gwrt") */ if (rt != NULL) { RT_LOCK_SPIN(rt); if (rt == hint0) { RT_REMREF_LOCKED(rt); RT_UNLOCK(rt); } else { RT_UNLOCK(rt); rtfree(rt); } } return (error); } #undef senderr /* * 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; struct timeval timenow; 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 = arp_route_to_gateway_route((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 || route->rt_llinfo == NULL) { char tmp[MAX_IPv4_STR_LEN]; /* In case result is 0 but no route, return an error */ if (result == 0) result = EHOSTUNREACH; if (log_arp_warnings && route != NULL && route->rt_llinfo == NULL) log(LOG_DEBUG, "arpresolve: can't allocate llinfo " "for %s\n", 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); getmicrotime(&timenow); if ((route->rt_rmx.rmx_expire == 0 || route->rt_rmx.rmx_expire > timenow.tv_sec) && gateway != NULL && gateway->sdl_family == AF_LINK && gateway->sdl_alen != 0) { bcopy(gateway, ll_dest, MIN(gateway->sdl_len, ll_dest_len)); result = 0; goto release; } if (ifp->if_flags & IFF_NOARP) { result = ENOTSUP; goto release; } /* * Route wasn't complete/valid. We need to arp. */ llinfo = route->rt_llinfo; if (packet != NULL) { if (llinfo->la_hold != NULL) m_freem(llinfo->la_hold); llinfo->la_hold = packet; } if (route->rt_rmx.rmx_expire) { route->rt_flags &= ~RTF_REJECT; if (llinfo->la_asked == 0 || route->rt_rmx.rmx_expire != timenow.tv_sec) { route->rt_rmx.rmx_expire = timenow.tv_sec; if (llinfo->la_asked++ < arp_maxtries) { struct ifaddr *rt_ifa = route->rt_ifa; ifaref(rt_ifa); RT_UNLOCK(route); dlil_send_arp(ifp, ARPOP_REQUEST, NULL, rt_ifa->ifa_addr, NULL, (const struct sockaddr*)net_dest); ifafree(rt_ifa); RT_LOCK(route); result = EJUSTRETURN; goto release; } else { route->rt_flags |= RTF_REJECT; route->rt_rmx.rmx_expire += arpt_down; llinfo->la_asked = 0; llinfo->la_hold = NULL; result = EHOSTUNREACH; goto release; } } } /* The packet is now held inside la_hold (can "packet" be NULL?) */ result = EJUSTRETURN; release: 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; 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; /* Do not respond to requests for 0.0.0.0 */ if (target_ip->sin_addr.s_addr == 0 && arpop == ARPOP_REQUEST) goto done; /* * Determine if this ARP is for us */ lck_rw_lock_shared(in_ifaddr_rwlock); TAILQ_FOREACH(ia, INADDR_HASH(target_ip->sin_addr.s_addr), ia_hash) { /* do_bridge should be tested here for bridging */ if (ia->ia_ifp == ifp && ia->ia_addr.sin_addr.s_addr == target_ip->sin_addr.s_addr) { best_ia = ia; ifaref(&best_ia->ia_ifa); lck_rw_done(in_ifaddr_rwlock); goto match; } } TAILQ_FOREACH(ia, INADDR_HASH(sender_ip->sin_addr.s_addr), ia_hash) { /* do_bridge should be tested here for bridging */ if (ia->ia_ifp == ifp && ia->ia_addr.sin_addr.s_addr == sender_ip->sin_addr.s_addr) { best_ia = ia; ifaref(&best_ia->ia_ifa); lck_rw_done(in_ifaddr_rwlock); goto match; } } 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) { if (ifa->ifa_addr->sa_family != AF_INET) continue; best_ia = (struct in_ifaddr *)ifa; ifaref(&best_ia->ia_ifa); break; } ifnet_lock_done(ifp); /* If we don't have an IP address on this interface, ignore the packet */ if (best_ia == NULL) goto done; match: /* If the packet is from this interface, ignore the packet */ if (!bcmp(CONST_LLADDR(sender_hw), ifnet_lladdr(ifp), sender_hw->sdl_len)) { goto done; } /* Check for a conflict */ if (sender_ip->sin_addr.s_addr == best_ia->ia_addr.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]; in_collision = (struct kev_in_collision*)storage; log(LOG_ERR, "%s%d duplicate IP address %s sent from address %s\n", ifp->if_name, ifp->if_unit, 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; strncpy(&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); 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->ia_addr.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 == 0 || route->rt_gateway == 0) { if (arpop != ARPOP_REQUEST) { goto respond; } if (arp_sendllconflict && send_conflicting_probes != 0 && (ifp->if_eflags & IFEF_ARPLL) != 0 && IN_LINKLOCAL(ntohl(target_ip->sin_addr.s_addr)) && sender_ip->sin_addr.s_addr == 0) { /* * 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) RT_LOCK_ASSERT_HELD(route); if (error == 0 && route && route->rt_gateway) { 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 (log_arp_warnings) { log(LOG_INFO, "arp: %s on %s%d sent probe for %s, already on %s%d\n", sdl_addr_to_hex(sender_hw, buf, sizeof(buf)), ifp->if_name, ifp->if_unit, inet_ntop(AF_INET, &target_ip->sin_addr, ipv4str, sizeof(ipv4str)), route->rt_ifp->if_name, route->rt_ifp->if_unit); log(LOG_INFO, "arp: sending conflicting probe to %s on %s%d\n", sdl_addr_to_hex(sender_hw, buf, sizeof(buf)), ifp->if_name, ifp->if_unit); } /* 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. */ ifnet_lock_shared(ifp); ifa = TAILQ_FIRST(&ifp->if_addrhead); if (ifa != NULL) ifaref(ifa); ifnet_lock_done(ifp); dlil_send_arp_internal(ifp, ARPOP_REQUEST, ifa != NULL ? SDL(ifa->ifa_addr) : NULL, (const struct sockaddr*)sender_ip, sender_hw, (const struct sockaddr*)target_ip); if (ifa != NULL) { ifafree(ifa); ifa = NULL; } } } 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) != 0) { 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); gateway = SDL(route->rt_gateway); if (route->rt_ifp != ifp) { if (!IN_LINKLOCAL(ntohl(sender_ip->sin_addr.s_addr)) || (ifp->if_eflags & IFEF_ARPLL) == 0) { if (log_arp_warnings) log(LOG_ERR, "arp: %s is on %s%d but got reply from %s on %s%d\n", inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof(ipv4str)), route->rt_ifp->if_name, route->rt_ifp->if_unit, sdl_addr_to_hex(sender_hw, buf, sizeof(buf)), ifp->if_name, ifp->if_unit); goto respond; } else { /* Don't change a permanent address */ if (route->rt_rmx.rmx_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 && 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; } /* Change the interface when the existing route is on */ route->rt_ifp = ifp; 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 && bcmp(LLADDR(gateway), CONST_LLADDR(sender_hw), gateway->sdl_alen)) { if (route->rt_rmx.rmx_expire && log_arp_warnings) { char buf2[3 * MAX_HW_LEN]; log(LOG_INFO, "arp: %s moved from %s to %s on %s%d\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)), ifp->if_name, ifp->if_unit); } else if (route->rt_rmx.rmx_expire == 0) { if (log_arp_warnings) { log(LOG_ERR, "arp: %s attempts to modify " "permanent entry for %s on %s%d\n", sdl_addr_to_hex(sender_hw, buf, sizeof(buf)), inet_ntop(AF_INET, &sender_ip->sin_addr, ipv4str, sizeof(ipv4str)), ifp->if_name, ifp->if_unit); } 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_rmx.rmx_expire) { struct timeval timenow; getmicrotime(&timenow); route->rt_rmx.rmx_expire = timenow.tv_sec + arpt_keep; } route->rt_flags &= ~RTF_REJECT; /* update the llinfo, send a queued packet if there is one */ llinfo = route->rt_llinfo; llinfo->la_asked = 0; if (llinfo->la_hold) { struct mbuf *m0; m0 = llinfo->la_hold; llinfo->la_hold = 0; RT_UNLOCK(route); dlil_output(ifp, PF_INET, m0, (caddr_t)route, rt_key(route), 0); RT_REMREF(route); route = NULL; } respond: if (route != NULL) { RT_REMREF_LOCKED(route); RT_UNLOCK(route); route = NULL; } if (arpop != ARPOP_REQUEST) goto done; /* If we are not the target, check if we should proxy */ if (target_ip->sin_addr.s_addr != best_ia->ia_addr.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); 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; } } 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); done: if (best_ia != NULL) ifafree(&best_ia->ia_ifa); return 0; } void arp_ifinit( struct ifnet *ifp, struct ifaddr *ifa) { ifa->ifa_rtrequest = arp_rtrequest; ifa->ifa_flags |= RTF_CLONING; dlil_send_arp(ifp, ARPOP_REQUEST, NULL, ifa->ifa_addr, NULL, ifa->ifa_addr); }