/* * Copyright (c) 2004, 2005 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Jeffrey M. Hsu. * * 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 DragonFly Project 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 COPYRIGHT HOLDERS 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 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * Copyright (c) 1982, 1986, 1988, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 * $FreeBSD: src/sys/netinet/if_ether.c,v 1.64.2.23 2003/04/11 07:23:15 fjoe Exp $ */ /* * Ethernet address resolution protocol. * TODO: * add "inuse/lock" bit (or ref. count) along with valid bit */ #include "opt_inet.h" #include "opt_carp.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CARP #include #endif #define SIN(s) ((struct sockaddr_in *)s) #define SDL(s) ((struct sockaddr_dl *)s) MALLOC_DEFINE(M_ARP, "arp", "ARP"); SYSCTL_DECL(_net_link_ether); SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 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 */ 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, ""); #define rt_expire rt_rmx.rmx_expire struct llinfo_arp { LIST_ENTRY(llinfo_arp) la_le; struct rtentry *la_rt; struct mbuf *la_hold; /* last packet until resolved/timeout */ u_short la_preempt; /* countdown for pre-expiry arps */ u_short la_asked; /* #times we QUERIED following expiration */ }; static int arp_maxtries = 5; static int useloopback = 1; /* use loopback interface for local traffic */ static int arp_proxyall = 0; static int arp_refresh = 60; /* refresh arp cache ~60 (not impl yet) */ static int arp_restricted_match = 0; static int arp_ignore_probes = 1; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, &arp_maxtries, 0, "ARP resolution attempts before returning error"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, &useloopback, 0, "Use the loopback interface for local traffic"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, &arp_proxyall, 0, "Enable proxy ARP for all suitable requests"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, restricted_match, CTLFLAG_RW, &arp_restricted_match, 0, "Only match against the sender"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, refresh, CTLFLAG_RW, &arp_refresh, 0, "Preemptively refresh the ARP"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, ignore_probes, CTLFLAG_RW, &arp_ignore_probes, 0, "Ignore ARP probes"); static void arp_rtrequest(int, struct rtentry *); static void arprequest(struct ifnet *, const struct in_addr *, const struct in_addr *, const u_char *); static void arprequest_async(struct ifnet *, const struct in_addr *, const struct in_addr *, const u_char *); static void arpintr(netmsg_t msg); static void arptfree(struct llinfo_arp *); static void arptimer(void *); static struct llinfo_arp * arplookup(in_addr_t, boolean_t, boolean_t); #ifdef INET static void in_arpinput(struct mbuf *); static void in_arpreply(struct mbuf *m, in_addr_t, in_addr_t); static void arp_update_msghandler(netmsg_t); static void arp_reply_msghandler(netmsg_t); #endif struct arp_pcpu_data { LIST_HEAD(, llinfo_arp) llinfo_list; struct callout timer_ch; struct netmsg_base timer_nmsg; }; static struct arp_pcpu_data *arp_data[MAXCPU]; /* * Timeout routine. Age arp_tab entries periodically. */ static void arptimer_dispatch(netmsg_t nmsg) { struct arp_pcpu_data *ad = nmsg->lmsg.u.ms_resultp; struct llinfo_arp *la, *nla; ASSERT_NETISR_NCPUS(mycpuid); /* Reply ASAP */ crit_enter(); netisr_replymsg(&nmsg->base, 0); crit_exit(); LIST_FOREACH_MUTABLE(la, &ad->llinfo_list, la_le, nla) { if (la->la_rt->rt_expire && la->la_rt->rt_expire <= time_uptime) arptfree(la); } callout_reset(&ad->timer_ch, arpt_prune * hz, arptimer, &ad->timer_nmsg); } static void arptimer(void *xnm) { struct netmsg_base *nm = xnm; KKASSERT(mycpuid < netisr_ncpus); crit_enter(); if (nm->lmsg.ms_flags & MSGF_DONE) netisr_sendmsg_oncpu(nm); crit_exit(); } /* * Parallel to llc_rtrequest. * * Called after a route is successfully added to the tree to fix-up the * route and initiate arp operations if required. */ static void arp_rtrequest(int req, struct rtentry *rt) { struct sockaddr *gate = rt->rt_gateway; struct llinfo_arp *la = rt->rt_llinfo; struct sockaddr_dl null_sdl = { sizeof null_sdl, AF_LINK }; 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) && 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. */ rt_setgate(rt, rt_key(rt), (struct sockaddr *)&null_sdl); gate = rt->rt_gateway; SDL(gate)->sdl_type = rt->rt_ifp->if_type; SDL(gate)->sdl_index = rt->rt_ifp->if_index; rt->rt_expire = time_uptime; break; } /* * Announce a new entry if requested, and only announce it * once on cpu0. */ if ((rt->rt_flags & RTF_ANNOUNCE) && mycpuid == 0) { arprequest(rt->rt_ifp, &SIN(rt_key(rt))->sin_addr, &SIN(rt_key(rt))->sin_addr, LLADDR(SDL(gate))); } /*FALLTHROUGH*/ case RTM_RESOLVE: if (gate->sa_family != AF_LINK || gate->sa_len < sizeof(struct sockaddr_dl)) { 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 != 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. */ R_Malloc(la, struct llinfo_arp *, sizeof *la); rt->rt_llinfo = la; if (la == NULL) { log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); break; } bzero(la, sizeof *la); la->la_rt = rt; rt->rt_flags |= RTF_LLINFO; LIST_INSERT_HEAD(&arp_data[mycpuid]->llinfo_list, la, la_le); #ifdef INET /* * 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))) { ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, LLADDR(SDL(gate))); SDL(gate)->sdl_alen = 6; rt->rt_expire = 0; } if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { memcpy(LLADDR(SDL(gate)), rt->rt_ifp->if_broadcastaddr, rt->rt_ifp->if_addrlen); SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; rt->rt_expire = 0; } #endif /* * This fixes up the routing interface for local addresses. * The route is adjusted to point at lo0 and the expiration * timer is disabled. * * NOTE: This prevents locally targetted traffic from going * out the hardware interface, which is inefficient * and might not work if the hardware cannot listen * to its own transmitted packets. Setting * net.link.ether.inet.useloopback to 0 will force * packets for local addresses out the hardware (and * it is expected to receive its own packet). * * XXX We should just be able to test RTF_LOCAL here instead * of having to compare IPs. */ if (SIN(rt_key(rt))->sin_addr.s_addr == (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { rt->rt_expire = 0; SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen; bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), rt->rt_ifp->if_addrlen); if (useloopback) rt->rt_ifp = loif; } break; case RTM_DELETE: if (la == NULL) break; LIST_REMOVE(la, la_le); rt->rt_llinfo = NULL; rt->rt_flags &= ~RTF_LLINFO; if (la->la_hold != NULL) m_freem(la->la_hold); R_Free(la); break; } } static struct mbuf * arpreq_alloc(struct ifnet *ifp, const struct in_addr *sip, const struct in_addr *tip, const u_char *enaddr) { struct mbuf *m; struct arphdr *ah; u_short ar_hrd; if ((m = m_gethdr(M_NOWAIT, MT_DATA)) == NULL) return NULL; m->m_pkthdr.rcvif = NULL; switch (ifp->if_type) { case IFT_ETHER: /* * This may not be correct for types not explicitly * listed, but this is our best guess */ default: ar_hrd = htons(ARPHRD_ETHER); m->m_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); m->m_pkthdr.len = m->m_len; MH_ALIGN(m, m->m_len); ah = mtod(m, struct arphdr *); break; } ah->ar_hrd = ar_hrd; ah->ar_pro = htons(ETHERTYPE_IP); ah->ar_hln = ifp->if_addrlen; /* hardware address length */ ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ ah->ar_op = htons(ARPOP_REQUEST); memcpy(ar_sha(ah), enaddr, ah->ar_hln); memset(ar_tha(ah), 0, ah->ar_hln); memcpy(ar_spa(ah), sip, ah->ar_pln); memcpy(ar_tpa(ah), tip, ah->ar_pln); return m; } static void arpreq_send(struct ifnet *ifp, struct mbuf *m) { struct sockaddr sa; struct ether_header *eh; ASSERT_NETISR_NCPUS(mycpuid); switch (ifp->if_type) { case IFT_ETHER: /* * This may not be correct for types not explicitly * listed, but this is our best guess */ default: eh = (struct ether_header *)sa.sa_data; /* if_output() will not swap */ eh->ether_type = htons(ETHERTYPE_ARP); memcpy(eh->ether_dhost, ifp->if_broadcastaddr, ifp->if_addrlen); break; } sa.sa_family = AF_UNSPEC; sa.sa_len = sizeof(sa); ifp->if_output(ifp, m, &sa, NULL); } static void arpreq_send_handler(netmsg_t msg) { struct mbuf *m = msg->packet.nm_packet; struct ifnet *ifp = msg->lmsg.u.ms_resultp; arpreq_send(ifp, m); /* nmsg was embedded in the mbuf, do not reply! */ } /* * Broadcast an ARP request. Caller specifies: * - arp header source ip address * - arp header target ip address * - arp header source ethernet address * * NOTE: Caller MUST NOT hold ifp's serializer */ static void arprequest(struct ifnet *ifp, const struct in_addr *sip, const struct in_addr *tip, const u_char *enaddr) { struct mbuf *m; ASSERT_NETISR_NCPUS(mycpuid); if (enaddr == NULL) { if (ifp->if_bridge) { enaddr = IF_LLADDR(ether_bridge_interface(ifp)); } else { enaddr = IF_LLADDR(ifp); } } m = arpreq_alloc(ifp, sip, tip, enaddr); if (m == NULL) return; arpreq_send(ifp, m); } /* * Same as arprequest(), except: * - Caller is allowed to hold ifp's serializer * - Network output is done in protocol thead */ static void arprequest_async(struct ifnet *ifp, const struct in_addr *sip, const struct in_addr *tip, const u_char *enaddr) { struct mbuf *m; struct netmsg_packet *pmsg; int cpu; if (enaddr == NULL) { if (ifp->if_bridge) { enaddr = IF_LLADDR(ether_bridge_interface(ifp)); } else { enaddr = IF_LLADDR(ifp); } } m = arpreq_alloc(ifp, sip, tip, enaddr); if (m == NULL) return; pmsg = &m->m_hdr.mh_netmsg; netmsg_init(&pmsg->base, NULL, &netisr_apanic_rport, 0, arpreq_send_handler); pmsg->nm_packet = m; pmsg->base.lmsg.u.ms_resultp = ifp; if (mycpuid < netisr_ncpus) cpu = mycpuid; else cpu = 0; lwkt_sendmsg(netisr_cpuport(cpu), &pmsg->base.lmsg); } /* * Resolve an IP address into an ethernet address. If success, * desten is filled in. If there is no entry in arptab, * set one up and broadcast a request for the IP address. * Hold onto this mbuf and resend it once the address * is finally resolved. A return value of 1 indicates * that desten has been filled in and the packet should be sent * normally; a 0 return indicates that the packet has been * taken over here, either now or for later transmission. */ int arpresolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m, struct sockaddr *dst, u_char *desten) { struct rtentry *rt = NULL; struct llinfo_arp *la = NULL; struct sockaddr_dl *sdl; int error; if (m->m_flags & M_BCAST) { /* broadcast */ memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); return 0; } if (m->m_flags & M_MCAST) {/* multicast */ ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); return 0; } if (rt0 != NULL) { error = rt_llroute(dst, rt0, &rt); if (error != 0) { m_freem(m); return error; } la = rt->rt_llinfo; } if (la == NULL) { la = arplookup(SIN(dst)->sin_addr.s_addr, TRUE, FALSE); if (la != NULL) rt = la->la_rt; } if (la == NULL || rt == NULL) { char addr[INET_ADDRSTRLEN]; log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", kinet_ntoa(SIN(dst)->sin_addr, addr), la ? "la" : " ", rt ? "rt" : ""); m_freem(m); return ENOBUFS; } /* * Check the address family and length is valid, the address * is resolved; otherwise, try to resolve. */ sdl = SDL(rt->rt_gateway); if ((rt->rt_expire == 0 || rt->rt_expire > time_uptime) && sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { /* * If entry has an expiry time and it is approaching, * see if we need to send an ARP request within this * arpt_down interval. */ if ((rt->rt_expire != 0) && (time_uptime + la->la_preempt > rt->rt_expire)) { arprequest(ifp, &SIN(rt->rt_ifa->ifa_addr)->sin_addr, &SIN(dst)->sin_addr, NULL); la->la_preempt--; } bcopy(LLADDR(sdl), desten, sdl->sdl_alen); return 0; } /* * If ARP is disabled or static on this interface, stop. * XXX * Probably should not allocate empty llinfo struct if we are * not going to be sending out an arp request. */ if (ifp->if_flags & (IFF_NOARP | IFF_STATICARP)) { m_freem(m); return ifp->if_flags & IFF_NOARP ? ENOTSUP : EINVAL; } /* * There is an arptab entry, but no ethernet address * response yet. Replace the held mbuf with this * latest one. */ if (la->la_hold != NULL) m_freem(la->la_hold); la->la_hold = m; /* * Return EWOULDBLOCK if we have tried less than arp_maxtries. It * will be masked by ether_output(). Return EHOSTDOWN/EHOSTUNREACH * if we have already sent arp_maxtries ARP requests. Retransmit the * ARP request, but not faster than one request per second. */ if (la->la_asked < arp_maxtries) error = EWOULDBLOCK; else error = (rt != NULL && rt->rt_flags & RTF_GATEWAY) ? EHOSTUNREACH : EHOSTDOWN; if (rt->rt_expire || ((rt->rt_flags & RTF_STATIC) && !sdl->sdl_alen)) { rt->rt_flags &= ~RTF_REJECT; if (la->la_asked == 0 || rt->rt_expire != time_uptime) { rt->rt_expire = time_uptime; arprequest(ifp, &SIN(rt->rt_ifa->ifa_addr)->sin_addr, &SIN(dst)->sin_addr, NULL); if (la->la_asked++ >= arp_maxtries) { rt->rt_expire += arpt_down; la->la_preempt = arp_maxtries; rt_rtmsg(RTM_MISS, rt, rt->rt_ifp, 0); } } } return error; } /* * Common length and type checks are done here, * then the protocol-specific routine is called. */ static void arpintr(netmsg_t msg) { struct mbuf *m = msg->packet.nm_packet; struct arphdr *ar; u_short ar_hrd; char hexstr[6]; if (m->m_len < sizeof(struct arphdr) && (m = m_pullup(m, sizeof(struct arphdr))) == NULL) { log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); return; } ar = mtod(m, struct arphdr *); ar_hrd = ntohs(ar->ar_hrd); if (ar_hrd != ARPHRD_ETHER && ar_hrd != ARPHRD_IEEE802) { hexncpy((unsigned char *)&ar->ar_hrd, 2, hexstr, 5, NULL); log(LOG_ERR, "arp: unknown hardware address format (0x%s)\n", hexstr); m_freem(m); return; } if (m->m_pkthdr.len < arphdr_len(ar)) { if ((m = m_pullup(m, arphdr_len(ar))) == NULL) { log(LOG_ERR, "arp: runt packet\n"); return; } ar = mtod(m, struct arphdr *); } switch (ntohs(ar->ar_pro)) { #ifdef INET case ETHERTYPE_IP: in_arpinput(m); return; #endif } m_freem(m); /* msg was embedded in the mbuf, do not reply! */ } #ifdef INET /* * ARP for Internet protocols on 10 Mb/s Ethernet. * Algorithm is that given in RFC 826. * In addition, a sanity check is performed on the sender * protocol address, to catch impersonators. * We no longer handle negotiations for use of trailer protocol: * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent * along with IP replies if we wanted trailers sent to us, * and also sent them in response to IP replies. * This allowed either end to announce the desire to receive * trailer packets. * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, * but formerly didn't normally send requests. */ static int log_arp_wrong_iface = 1; static int log_arp_movements = 1; static int log_arp_permanent_modify = 1; static int log_arp_creation_failure = 1; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, &log_arp_wrong_iface, 0, "Log arp packets arriving on the wrong interface"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, &log_arp_movements, 0, "Log arp replies from MACs different than the one in the cache"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, &log_arp_permanent_modify, 0, "Log arp replies from MACs different than the one " "in the permanent arp entry"); SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_creation_failure, CTLFLAG_RW, &log_arp_creation_failure, 0, "Log arp creation failure"); /* * Returns non-zero if the routine updated anything. */ static int arp_update_oncpu(struct mbuf *m, in_addr_t saddr, boolean_t create, boolean_t dologging) { struct arphdr *ah = mtod(m, struct arphdr *); struct ifnet *ifp = m->m_pkthdr.rcvif; struct llinfo_arp *la; struct sockaddr_dl *sdl; struct rtentry *rt; char hexstr[2][64]; char sbuf[INET_ADDRSTRLEN]; int changed = create; KASSERT(curthread->td_type == TD_TYPE_NETISR, ("arp update not in netisr")); la = arplookup(saddr, create, FALSE); if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { struct in_addr isaddr = { saddr }; int rt_cmd = sdl->sdl_alen == 0 ? RTM_ADD : RTM_CHANGE; bool do_rtmsg = false; /* * Normally arps coming in on the wrong interface are ignored, * but if we are bridging and the two interfaces belong to * the same bridge, or one is a member of the bridge which * is the other, then it isn't an error. */ if (rt->rt_ifp != ifp) { /* * (1) ifp and rt_ifp both members of same bridge * (2) rt_ifp member of bridge ifp * (3) ifp member of bridge rt_ifp * * Always replace rt_ifp with the bridge ifc. */ struct ifnet *nifp; if (ifp->if_bridge && rt->rt_ifp->if_bridge == ifp->if_bridge) { nifp = ether_bridge_interface(ifp); } else if (rt->rt_ifp->if_bridge && ether_bridge_interface(rt->rt_ifp) == ifp) { nifp = ifp; } else if (ifp->if_bridge && ether_bridge_interface(ifp) == rt->rt_ifp) { nifp = rt->rt_ifp; } else { nifp = NULL; } if ((log_arp_wrong_iface == 1 && nifp == NULL) || log_arp_wrong_iface == 2) { hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_ERR, "arp: %s is on %s " "but got reply from %s on %s\n", kinet_ntoa(isaddr, sbuf), rt->rt_ifp->if_xname, hexstr[0], ifp->if_xname); } if (nifp == NULL) return 0; /* * nifp is our man! Replace rt_ifp and adjust * the sdl. */ ifp = rt->rt_ifp = nifp; if (sdl->sdl_type != ifp->if_type) { sdl->sdl_type = ifp->if_type; changed = 1; do_rtmsg = true; } if (sdl->sdl_index != ifp->if_index) { sdl->sdl_index = ifp->if_index; changed = 1; do_rtmsg = true; } } if (sdl->sdl_alen && bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { changed = 1; if (rt->rt_expire != 0) { if (dologging && log_arp_movements) { hexncpy((u_char *)LLADDR(sdl), ifp->if_addrlen, hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr[1], HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_INFO, "arp: %s moved from %s to %s on %s\n", kinet_ntoa(isaddr, sbuf), hexstr[0], hexstr[1], ifp->if_xname); } } else { if (dologging && log_arp_permanent_modify) { hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_ERR, "arp: %s attempts to modify " "permanent entry for %s on %s\n", hexstr[0], kinet_ntoa(isaddr, sbuf), ifp->if_xname); } return changed; } do_rtmsg = true; } /* * sanity check for the address length. * XXX this does not work for protocols with variable address * length. -is */ if (dologging && sdl->sdl_alen && sdl->sdl_alen != ah->ar_hln) { hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_WARNING, "arp from %s: new addr len %d, was %d", hexstr[0], ah->ar_hln, sdl->sdl_alen); } if (ifp->if_addrlen != ah->ar_hln) { if (dologging) { hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr[0], HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_WARNING, "arp from %s: addr len: new %d, i/f %d " "(ignored)", hexstr[0], ah->ar_hln, ifp->if_addrlen); } return changed; } if (sdl->sdl_alen == 0) do_rtmsg = true; memcpy(LLADDR(sdl), ar_sha(ah), sdl->sdl_alen = ah->ar_hln); if (rt->rt_expire != 0) { if (rt->rt_expire != time_uptime + arpt_keep && rt->rt_expire != time_uptime + arpt_keep - 1) { rt->rt_expire = time_uptime + arpt_keep; changed = 1; } } if (rt->rt_flags & RTF_REJECT) { rt->rt_flags &= ~RTF_REJECT; changed = 1; } if (la->la_asked != 0) { la->la_asked = 0; changed = 1; } if (la->la_preempt != arp_maxtries) { la->la_preempt = arp_maxtries; changed = 1; } /* * This particular cpu might have been holding an mbuf * pending ARP resolution. If so, transmit the mbuf now. */ if (la->la_hold != NULL) { struct mbuf *m = la->la_hold; la->la_hold = NULL; m_adj(m, sizeof(struct ether_header)); ifp->if_output(ifp, m, rt_key(rt), rt); changed = 1; } if (do_rtmsg && mycpuid == 0) rt_rtmsg(rt_cmd, rt, rt->rt_ifp, 0); } return changed; } /* * Called from arpintr() - this routine is run from a single cpu. */ static void in_arpinput(struct mbuf *m) { struct arphdr *ah; struct ifnet *ifp = m->m_pkthdr.rcvif; struct ifaddr_container *ifac; struct in_ifaddr_container *iac; struct in_ifaddr *ia = NULL; struct in_addr isaddr, itaddr, myaddr; uint8_t *enaddr = NULL; int req_len; int changed; char hexstr[64], sbuf[INET_ADDRSTRLEN]; req_len = arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); if (m->m_len < req_len && (m = m_pullup(m, req_len)) == NULL) { log(LOG_ERR, "in_arp: runt packet -- m_pullup failed\n"); return; } ah = mtod(m, struct arphdr *); memcpy(&isaddr, ar_spa(ah), sizeof isaddr); memcpy(&itaddr, ar_tpa(ah), sizeof itaddr); /* * Check both target and sender IP addresses: * * If we receive the packet on the interface owning the address, * then accept the address. * * For a bridge, we accept the address if the receive interface and * the interface owning the address are on the same bridge, and * use the bridge MAC as the is-at response. The bridge will be * responsible for handling the packet. * * (0) Check target IP against CARP IPs */ #ifdef CARP LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { int is_match = 0, is_parent = 0; ia = iac->ia; /* Skip all ia's which don't match */ if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) continue; if (ia->ia_ifp->if_type != IFT_CARP) continue; if (carp_parent(ia->ia_ifp) == ifp) is_parent = 1; if (is_parent || ia->ia_ifp == ifp) is_match = carp_iamatch(ia); if (is_match) { if (is_parent) { /* * The parent interface will also receive * the ethernet broadcast packets, e.g. ARP * REQUEST, so if we could find a CARP * interface of the parent that could match * the target IP address, we then drop the * packets, which is delieverd to us through * the parent interface. */ m_freem(m); return; } goto match; } } #endif /* CARP */ /* * (1) Check target IP against our local IPs */ LIST_FOREACH(iac, INADDR_HASH(itaddr.s_addr), ia_hash) { ia = iac->ia; /* Skip all ia's which don't match */ if (itaddr.s_addr != ia->ia_addr.sin_addr.s_addr) continue; #ifdef CARP /* CARP interfaces are checked in (0) */ if (ia->ia_ifp->if_type == IFT_CARP) continue; #endif if (ifp->if_bridge && ia->ia_ifp && ifp->if_bridge == ia->ia_ifp->if_bridge) { ifp = ether_bridge_interface(ifp); goto match; } if (ia->ia_ifp && ia->ia_ifp->if_bridge && ether_bridge_interface(ia->ia_ifp) == ifp) { goto match; } if (ifp->if_bridge && ether_bridge_interface(ifp) == ia->ia_ifp) { goto match; } if (ia->ia_ifp == ifp) { goto match; } } /* * (2) Check sender IP against our local IPs */ LIST_FOREACH(iac, INADDR_HASH(isaddr.s_addr), ia_hash) { ia = iac->ia; /* Skip all ia's which don't match */ if (isaddr.s_addr != ia->ia_addr.sin_addr.s_addr) continue; if (ifp->if_bridge && ia->ia_ifp && ifp->if_bridge == ia->ia_ifp->if_bridge) { ifp = ether_bridge_interface(ifp); goto match; } if (ia->ia_ifp && ia->ia_ifp->if_bridge && ether_bridge_interface(ia->ia_ifp) == ifp) { goto match; } if (ifp->if_bridge && ether_bridge_interface(ifp) == ia->ia_ifp) { goto match; } if (ia->ia_ifp == ifp) goto match; } /* * No match, use the first inet address on the receive interface * as a dummy address for the rest of the function. */ TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { struct ifaddr *ifa = ifac->ifa; if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { ia = ifatoia(ifa); goto match; } } /* * If we got here, we didn't find any suitable interface, * so drop the packet. */ m_freem(m); return; match: if (!enaddr) enaddr = (uint8_t *)IF_LLADDR(ifp); myaddr = ia->ia_addr.sin_addr; if (!bcmp(ar_sha(ah), enaddr, ifp->if_addrlen)) { m_freem(m); /* it's from me, ignore it. */ return; } if (!bcmp(ar_sha(ah), ifp->if_broadcastaddr, ifp->if_addrlen)) { log(LOG_ERR, "arp: link address is broadcast for IP address %s!\n", kinet_ntoa(isaddr, sbuf)); m_freem(m); return; } if (isaddr.s_addr == myaddr.s_addr && myaddr.s_addr != 0) { hexncpy((u_char *)ar_sha(ah), ifp->if_addrlen, hexstr, HEX_NCPYLEN(ifp->if_addrlen), ":"); log(LOG_ERR, "arp: %s is using my IP address %s!\n", hexstr, kinet_ntoa(isaddr, sbuf)); itaddr = myaddr; goto reply; } if (ifp->if_flags & IFF_STATICARP) goto reply; /* * When arp_restricted_match is true and the ARP response is not * specifically targetted to me, ignore it. Otherwise the entry * timeout may be updated for an old MAC. */ if (arp_restricted_match && itaddr.s_addr != myaddr.s_addr) { m_freem(m); return; } /* * Update all CPU's routing tables with this ARP packet. * * However, we only need to generate rtmsg on CPU0. */ ASSERT_NETISR0; changed = arp_update_oncpu(m, isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, TRUE); if (netisr_ncpus > 1 && changed) { struct netmsg_inarp *msg = &m->m_hdr.mh_arpmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, arp_update_msghandler); msg->m = m; msg->saddr = isaddr.s_addr; msg->taddr = itaddr.s_addr; msg->myaddr = myaddr.s_addr; lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); } else { goto reply; } /* * Just return here; after all CPUs's routing tables are * properly updated by this ARP packet, an ARP reply will * be generated if appropriate. */ return; reply: in_arpreply(m, itaddr.s_addr, myaddr.s_addr); } static void arp_reply_msghandler(netmsg_t msg) { struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; in_arpreply(rmsg->m, rmsg->taddr, rmsg->myaddr); /* Don't reply this netmsg; netmsg_inarp is embedded in mbuf */ } static void arp_update_msghandler(netmsg_t msg) { struct netmsg_inarp *rmsg = (struct netmsg_inarp *)msg; int nextcpu; ASSERT_NETISR_NCPUS(mycpuid); /* * This message handler will be called on all of the APs; * no need to generate rtmsg on them. */ KASSERT(mycpuid > 0, ("arp update msg on cpu%d", mycpuid)); arp_update_oncpu(rmsg->m, rmsg->saddr, rmsg->taddr == rmsg->myaddr, FALSE); nextcpu = mycpuid + 1; if (nextcpu < netisr_ncpus) { lwkt_forwardmsg(netisr_cpuport(nextcpu), &rmsg->base.lmsg); } else { struct mbuf *m = rmsg->m; in_addr_t saddr = rmsg->saddr; in_addr_t taddr = rmsg->taddr; in_addr_t myaddr = rmsg->myaddr; /* * Dispatch this mbuf to netisr0 to perform ARP reply, * if appropriate. * NOTE: netmsg_inarp is embedded in this mbuf. */ netmsg_init(&rmsg->base, NULL, &netisr_apanic_rport, 0, arp_reply_msghandler); rmsg->m = m; rmsg->saddr = saddr; rmsg->taddr = taddr; rmsg->myaddr = myaddr; lwkt_sendmsg(netisr_cpuport(0), &rmsg->base.lmsg); } } /* * Reply to an arp request */ static void in_arpreply(struct mbuf *m, in_addr_t taddr, in_addr_t myaddr) { struct ifnet *ifp = m->m_pkthdr.rcvif; const uint8_t *enaddr; struct arphdr *ah; struct sockaddr sa; struct ether_header *eh; ASSERT_NETISR0; ah = mtod(m, struct arphdr *); if (ntohs(ah->ar_op) != ARPOP_REQUEST) { m_freem(m); return; } enaddr = (const uint8_t *)IF_LLADDR(ifp); if (taddr == myaddr) { /* I am the target */ memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); memcpy(ar_sha(ah), enaddr, ah->ar_hln); } else { struct llinfo_arp *la; struct rtentry *rt; la = arplookup(taddr, FALSE, SIN_PROXY); if (la == NULL) { struct sockaddr_in sin; #ifdef DEBUG_PROXY char tbuf[INET_ADDRSTRLEN]; #endif if (!arp_proxyall) { m_freem(m); return; } bzero(&sin, sizeof sin); sin.sin_family = AF_INET; sin.sin_len = sizeof sin; sin.sin_addr.s_addr = taddr; rt = rtpurelookup((struct sockaddr *)&sin); if (rt == NULL) { m_freem(m); return; } --rt->rt_refcnt; /* * Don't send proxies for nodes on the same interface * as this one came out of, or we'll get into a fight * over who claims what Ether address. * * If the rt entry is associated with a bridge, we * count it as the 'same' interface if ifp is * associated with the bridge. */ if (rt->rt_ifp == ifp || rt->rt_ifp == ifp->if_bridge) { m_freem(m); return; } memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); memcpy(ar_sha(ah), enaddr, ah->ar_hln); #ifdef DEBUG_PROXY kprintf("arp: proxying for %s\n", kinet_ntoa(itaddr, tbuf)); #endif } else { struct sockaddr_dl *sdl; rt = la->la_rt; memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); sdl = SDL(rt->rt_gateway); memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); } } memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); memcpy(ar_spa(ah), &taddr, ah->ar_pln); ah->ar_op = htons(ARPOP_REPLY); ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ switch (ifp->if_type) { case IFT_ETHER: /* * May not be correct for types not explictly * listed, but it is our best guess. */ default: eh = (struct ether_header *)sa.sa_data; memcpy(eh->ether_dhost, ar_tha(ah), sizeof eh->ether_dhost); eh->ether_type = htons(ETHERTYPE_ARP); break; } sa.sa_family = AF_UNSPEC; sa.sa_len = sizeof sa; ifp->if_output(ifp, m, &sa, NULL); } #endif /* INET */ /* * Free an arp entry. If the arp entry is actively referenced or represents * a static entry we only clear it back to an unresolved state, otherwise * we destroy the entry entirely. * * Note that static entries are created when route add ... -interface is used * to create an interface route to a (direct) destination. */ static void arptfree(struct llinfo_arp *la) { struct rtentry *rt = la->la_rt; struct sockaddr_dl *sdl; if (rt == NULL) panic("arptfree"); sdl = SDL(rt->rt_gateway); if (sdl != NULL && ((rt->rt_refcnt > 0 && sdl->sdl_family == AF_LINK) || (rt->rt_flags & RTF_STATIC))) { sdl->sdl_alen = 0; la->la_preempt = la->la_asked = 0; rt->rt_flags &= ~RTF_REJECT; return; } /* * ARP expiry happens under one big timer. * To avoid overflowing the route socket, don't report this. * Now that RTM_MISS is reported when an address is unresolvable * the benefit of reporting this deletion is questionable. */ rtrequest(RTM_DELETE, rt_key(rt), NULL, rt_mask(rt), 0, NULL); } /* * Lookup or enter a new address in arptab. */ static struct llinfo_arp * arplookup(in_addr_t addr, boolean_t create, boolean_t proxy) { struct rtentry *rt; struct sockaddr_inarp sin = { sizeof sin, AF_INET }; const char *why = NULL; /* Check ARP probes, e.g. from Cisco switches. */ if (addr == INADDR_ANY && arp_ignore_probes) return (NULL); sin.sin_addr.s_addr = addr; sin.sin_other = proxy ? SIN_PROXY : 0; if (create) { rt = rtlookup((struct sockaddr *)&sin); } else { rt = rtpurelookup((struct sockaddr *)&sin); } if (rt == NULL) return (NULL); rt->rt_refcnt--; if (rt->rt_flags & RTF_GATEWAY) why = "host is not on local network"; else if (!(rt->rt_flags & RTF_LLINFO)) why = "could not allocate llinfo"; else if (rt->rt_gateway->sa_family != AF_LINK) why = "gateway route is not ours"; if (why) { if (create && log_arp_creation_failure) { char abuf[INET_ADDRSTRLEN]; log(LOG_DEBUG, "arplookup %s failed: %s\n", kinet_ntoa(sin.sin_addr, abuf), why); } if (rt->rt_refcnt <= 0 && (rt->rt_flags & RTF_WASCLONED)) { /* No references to this route. Purge it. */ rtrequest(RTM_DELETE, rt_key(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, NULL); } return (NULL); } return (rt->rt_llinfo); } void arp_ifinit(struct ifnet *ifp, struct ifaddr *ifa) { ifa->ifa_rtrequest = arp_rtrequest; ifa->ifa_flags |= RTF_CLONING; } void arp_gratuitous(struct ifnet *ifp, struct ifaddr *ifa) { if (IA_SIN(ifa)->sin_addr.s_addr != INADDR_ANY) { if (IN_NETISR_NCPUS(mycpuid)) { arprequest(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, NULL); } else { arprequest_async(ifp, &IA_SIN(ifa)->sin_addr, &IA_SIN(ifa)->sin_addr, NULL); } } } static void arp_ifaddr(void *arg __unused, struct ifnet *ifp, enum ifaddr_event event, struct ifaddr *ifa) { if (ifa->ifa_rtrequest != arp_rtrequest) /* XXX need a generic way */ return; if (ifa->ifa_addr->sa_family != AF_INET) return; if (event == IFADDR_EVENT_DELETE) return; /* * - CARP interfaces will take care of gratuitous ARP themselves. * - If we are the CARP interface's parent, don't send gratuitous * ARP to avoid unnecessary confusion. */ #ifdef CARP if (ifp->if_type != IFT_CARP && ifp->if_carp == NULL) #endif { arp_gratuitous(ifp, ifa); } } static void arp_init_dispatch(netmsg_t nm) { struct arp_pcpu_data *ad; ASSERT_NETISR_NCPUS(mycpuid); ad = kmalloc(sizeof(*ad), M_ARP, M_WAITOK | M_ZERO); LIST_INIT(&ad->llinfo_list); callout_init_mp(&ad->timer_ch); netmsg_init(&ad->timer_nmsg, NULL, &netisr_adone_rport, MSGF_PRIORITY, arptimer_dispatch); ad->timer_nmsg.lmsg.u.ms_resultp = ad; arp_data[mycpuid] = ad; callout_reset(&ad->timer_ch, hz, arptimer, &ad->timer_nmsg); netisr_forwardmsg(&nm->base, mycpuid + 1); } static void arp_init(void) { struct netmsg_base nm; netmsg_init(&nm, NULL, &curthread->td_msgport, 0, arp_init_dispatch); netisr_domsg_global(&nm); netisr_register(NETISR_ARP, arpintr, NULL); EVENTHANDLER_REGISTER(ifaddr_event, arp_ifaddr, NULL, EVENTHANDLER_PRI_LAST); } SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0);