diff options
Diffstat (limited to 'sys/netinet/if_ether.c')
| -rw-r--r-- | sys/netinet/if_ether.c | 951 |
1 files changed, 951 insertions, 0 deletions
diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c new file mode 100644 index 0000000..77eee3c --- /dev/null +++ b/sys/netinet/if_ether.c @@ -0,0 +1,951 @@ +/* + * 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. 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. + * + * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 + * $FreeBSD$ + */ + +/* + * Ethernet address resolution protocol. + * TODO: + * add "inuse/lock" bit (or ref. count) along with valid bit + */ + +#include "opt_inet.h" +#include "opt_bdg.h" + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/queue.h> +#include <sys/sysctl.h> +#include <sys/systm.h> +#include <sys/mbuf.h> +#include <sys/malloc.h> +#include <sys/socket.h> +#include <sys/syslog.h> + +#include <net/if.h> +#include <net/if_dl.h> +#include <net/if_types.h> +#include <net/route.h> +#include <net/netisr.h> +#include <net/if_llc.h> +#ifdef BRIDGE +#include <net/ethernet.h> +#include <net/bridge.h> +#endif + +#include <netinet/in.h> +#include <netinet/in_var.h> +#include <netinet/if_ether.h> + +#include <net/if_arc.h> +#include <net/iso88025.h> + +#define SIN(s) ((struct sockaddr_in *)s) +#define SDL(s) ((struct sockaddr_dl *)s) + +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 */ + long la_asked; /* last time we QUERIED for this addr */ +#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ +}; + +static LIST_HEAD(, llinfo_arp) llinfo_arp; + +struct ifqueue arpintrq; +static int arp_inuse, arp_allocated, arpinit_done; + +static int arp_maxtries = 5; +static int useloopback = 1; /* use loopback interface for local traffic */ +static int arp_proxyall = 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, ""); + +static void arp_init(void); +static void arp_rtrequest(int, struct rtentry *, struct rt_addrinfo *); +static void arprequest(struct ifnet *, + struct in_addr *, struct in_addr *, u_char *); +static void arpintr(void); +static void arptfree(struct llinfo_arp *); +static void arptimer(void *); +static struct llinfo_arp + *arplookup(u_long, int, int); +#ifdef INET +static void in_arpinput(struct mbuf *); +#endif + +/* + * Timeout routine. Age arp_tab entries periodically. + */ +/* ARGSUSED */ +static void +arptimer(ignored_arg) + void *ignored_arg; +{ + int s = splnet(); + register struct llinfo_arp *la = LIST_FIRST(&llinfo_arp); + struct llinfo_arp *ola; + + timeout(arptimer, (caddr_t)0, arpt_prune * hz); + while ((ola = la) != 0) { + register struct rtentry *rt = la->la_rt; + la = LIST_NEXT(la, la_le); + if (rt->rt_expire && rt->rt_expire <= time_second) + arptfree(ola); /* timer has expired, clear */ + } + splx(s); +} + +/* + * Parallel to llc_rtrequest. + */ +static void +arp_rtrequest(req, rt, info) + int req; + register struct rtentry *rt; + struct rt_addrinfo *info; +{ + register struct sockaddr *gate = rt->rt_gateway; + register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; + static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; + + if (!arpinit_done) { + arpinit_done = 1; + timeout(arptimer, (caddr_t)0, hz); + } + if (rt->rt_flags & RTF_GATEWAY) + return; + switch (req) { + + case RTM_ADD: + /* + * XXX: If this is a manually added route to interface + * such as older version of routed or gated might provide, + * restore cloning bit. + */ + if ((rt->rt_flags & RTF_HOST) == 0 && + 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_second; + break; + } + /* Announce a new entry if requested. */ + if (rt->rt_flags & RTF_ANNOUNCE) + arprequest(rt->rt_ifp, + &SIN(rt_key(rt))->sin_addr, + &SIN(rt_key(rt))->sin_addr, + (u_char *)LLADDR(SDL(gate))); + /*FALLTHROUGH*/ + case RTM_RESOLVE: + if (gate->sa_family != AF_LINK || + gate->sa_len < sizeof(null_sdl)) { + 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. + */ + R_Malloc(la, struct llinfo_arp *, sizeof(*la)); + rt->rt_llinfo = (caddr_t)la; + if (la == 0) { + log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); + break; + } + 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); + +#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)) && + rt->rt_ifp->if_type != IFT_ARCNET) { + 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 + + 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; + Bcopy(IF_LLADDR(rt->rt_ifp), LLADDR(SDL(gate)), + SDL(gate)->sdl_alen = rt->rt_ifp->if_addrlen); + if (useloopback) + rt->rt_ifp = loif; + + } + break; + + case RTM_DELETE: + if (la == 0) + break; + arp_inuse--; + LIST_REMOVE(la, la_le); + rt->rt_llinfo = 0; + rt->rt_flags &= ~RTF_LLINFO; + if (la->la_hold) + m_freem(la->la_hold); + Free((caddr_t)la); + } +} + +/* + * Broadcast an ARP request. Caller specifies: + * - arp header source ip address + * - arp header target ip address + * - arp header source ethernet address + */ +static void +arprequest(ifp, sip, tip, enaddr) + register struct ifnet *ifp; + register struct in_addr *sip, *tip; + register u_char *enaddr; +{ + register struct mbuf *m; + register struct ether_header *eh; + register struct arc_header *arh; + register struct arphdr *ah; + struct sockaddr sa; + static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, + LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; + u_short ar_hrd; + + if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) + return; + m->m_pkthdr.rcvif = (struct ifnet *)0; + switch (ifp->if_type) { + case IFT_ARCNET: + ar_hrd = htons(ARPHRD_ARCNET); + + 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); + + arh = (struct arc_header *)sa.sa_data; + arh->arc_dhost = *ifp->if_broadcastaddr; + arh->arc_type = ARCTYPE_ARP; + + ah = mtod(m, struct arphdr *); + break; + + case IFT_ISO88025: + ar_hrd = htons(ARPHRD_IEEE802); + + m->m_len = sizeof(llcx) + + arphdr_len2(ifp->if_addrlen, sizeof(struct in_addr)); + m->m_pkthdr.len = m->m_len; + MH_ALIGN(m, m->m_len); + + (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); + (void)memcpy(sa.sa_data, ifp->if_broadcastaddr, 6); + (void)memcpy(sa.sa_data + 6, enaddr, 6); + sa.sa_data[6] |= TR_RII; + sa.sa_data[12] = TR_AC; + sa.sa_data[13] = TR_LLC_FRAME; + + ah = (struct arphdr *)(mtod(m, char *) + sizeof(llcx)); + break; + case IFT_FDDI: + 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); + + eh = (struct ether_header *)sa.sa_data; + /* if_output will not swap */ + eh->ether_type = htons(ETHERTYPE_ARP); + (void)memcpy(eh->ether_dhost, ifp->if_broadcastaddr, + sizeof(eh->ether_dhost)); + + 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); + (void)memcpy(ar_sha(ah), enaddr, ah->ar_hln); + (void)memcpy(ar_spa(ah), sip, ah->ar_pln); + (void)memcpy(ar_tpa(ah), tip, ah->ar_pln); + + sa.sa_family = AF_UNSPEC; + sa.sa_len = sizeof(sa); + (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); +} + +/* + * Resolve an IP address into an ethernet address. If success, + * desten is filled in. If there is no entry in arptab, + * set one up and broadcast a request for the IP address. + * Hold onto this mbuf and resend it once the address + * is finally resolved. A return value of 1 indicates + * that desten has been filled in and the packet should be sent + * normally; a 0 return indicates that the packet has been + * taken over here, either now or for later transmission. + */ +int +arpresolve(ifp, rt, m, dst, desten, rt0) + register struct ifnet *ifp; + register struct rtentry *rt; + struct mbuf *m; + register struct sockaddr *dst; + register u_char *desten; + struct rtentry *rt0; +{ + struct llinfo_arp *la = 0; + struct sockaddr_dl *sdl; + + if (m->m_flags & M_BCAST) { /* broadcast */ + (void)memcpy(desten, ifp->if_broadcastaddr, ifp->if_addrlen); + return (1); + } + if (m->m_flags & M_MCAST && ifp->if_type != IFT_ARCNET) {/* multicast */ + ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); + return(1); + } + if (rt) + la = (struct llinfo_arp *)rt->rt_llinfo; + if (la == 0) { + la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); + if (la) + rt = la->la_rt; + } + if (la == 0 || rt == 0) { + log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", + inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", + rt ? "rt" : ""); + m_freem(m); + return (0); + } + sdl = SDL(rt->rt_gateway); + /* + * Check the address family and length is valid, the address + * is resolved; otherwise, try to resolve. + */ + if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && + sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { + /* + * 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_second + (arp_maxtries - la->la_asked) * arpt_down > + rt->rt_expire)) { + arprequest(ifp, + &SIN(rt->rt_ifa->ifa_addr)->sin_addr, + &SIN(dst)->sin_addr, + IF_LLADDR(ifp)); + la->la_asked++; + } + + bcopy(LLADDR(sdl), desten, sdl->sdl_alen); + return 1; + } + /* + * If ARP is disabled 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) { + m_freem(m); + return (0); + } + /* + * There is an arptab entry, but no ethernet address + * response yet. Replace the held mbuf with this + * latest one. + */ + if (la->la_hold) + m_freem(la->la_hold); + la->la_hold = m; + if (rt->rt_expire) { + rt->rt_flags &= ~RTF_REJECT; + if (la->la_asked == 0 || rt->rt_expire != time_second) { + rt->rt_expire = time_second; + if (la->la_asked++ < arp_maxtries) + arprequest(ifp, + &SIN(rt->rt_ifa->ifa_addr)->sin_addr, + &SIN(dst)->sin_addr, + IF_LLADDR(ifp)); + else { + rt->rt_flags |= RTF_REJECT; + rt->rt_expire += arpt_down; + la->la_asked = 0; + } + + } + } + return (0); +} + +/* + * Common length and type checks are done here, + * then the protocol-specific routine is called. + */ +static void +arpintr() +{ + register struct mbuf *m; + register struct arphdr *ar; + int s; + + if (!arpinit_done) { + arpinit_done = 1; + timeout(arptimer, (caddr_t)0, hz); + } + while (arpintrq.ifq_head) { + s = splimp(); + IF_DEQUEUE(&arpintrq, m); + splx(s); + if (m == 0 || (m->m_flags & M_PKTHDR) == 0) + panic("arpintr"); + + 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"); + continue; + } + ar = mtod(m, struct arphdr *); + + if (ntohs(ar->ar_hrd) != ARPHRD_ETHER + && ntohs(ar->ar_hrd) != ARPHRD_IEEE802 + && ntohs(ar->ar_hrd) != ARPHRD_ARCNET) { + log(LOG_ERR, + "arp: unknown hardware address format (0x%2D)\n", + (unsigned char *)&ar->ar_hrd, ""); + m_freem(m); + continue; + } + + if (m->m_pkthdr.len < arphdr_len(ar) && + (m = m_pullup(m, arphdr_len(ar))) == NULL) { + log(LOG_ERR, "arp: runt packet\n"); + m_freem(m); + continue; + } + + switch (ntohs(ar->ar_pro)) { +#ifdef INET + case ETHERTYPE_IP: + in_arpinput(m); + continue; +#endif + } + m_freem(m); + } +} + +#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; + +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"); + + +static void +in_arpinput(m) + struct mbuf *m; +{ + register struct arphdr *ah; + register struct ifnet *ifp = m->m_pkthdr.rcvif; + struct ether_header *eh; + struct arc_header *arh; + struct iso88025_header *th = (struct iso88025_header *)0; + struct iso88025_sockaddr_dl_data *trld; + register struct llinfo_arp *la = 0; + register struct rtentry *rt; + struct ifaddr *ifa; + struct in_ifaddr *ia; + struct sockaddr_dl *sdl; + struct sockaddr sa; + struct in_addr isaddr, itaddr, myaddr; + int op, rif_len; + int req_len; + + 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 *); + op = ntohs(ah->ar_op); + (void)memcpy(&isaddr, ar_spa(ah), sizeof (isaddr)); + (void)memcpy(&itaddr, ar_tpa(ah), sizeof (itaddr)); +#ifdef BRIDGE +#define BRIDGE_TEST (do_bridge) +#else +#define BRIDGE_TEST (0) /* cc will optimise the test away */ +#endif + /* + * For a bridge, we want to check the address irrespective + * of the receive interface. (This will change slightly + * when we have clusters of interfaces). + */ + LIST_FOREACH(ia, INADDR_HASH(itaddr.s_addr), ia_hash) + if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && + itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) + goto match; + LIST_FOREACH(ia, INADDR_HASH(isaddr.s_addr), ia_hash) + if ((BRIDGE_TEST || (ia->ia_ifp == ifp)) && + isaddr.s_addr == ia->ia_addr.sin_addr.s_addr) + 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(ifa, &ifp->if_addrhead, ifa_link) + if (ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET) { + ia = ifatoia(ifa); + goto match; + } + /* + * If bridging, fall back to using any inet address. + */ + if (!BRIDGE_TEST || + (ia = TAILQ_FIRST(&in_ifaddrhead)) == NULL) { + m_freem(m); + return; + } +match: + myaddr = ia->ia_addr.sin_addr; + if (!bcmp(ar_sha(ah), IF_LLADDR(ifp), 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", + inet_ntoa(isaddr)); + m_freem(m); + return; + } + if (isaddr.s_addr == myaddr.s_addr) { + log(LOG_ERR, + "arp: %*D is using my IP address %s!\n", + ifp->if_addrlen, (u_char *)ar_sha(ah), ":", + inet_ntoa(isaddr)); + itaddr = myaddr; + goto reply; + } + la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); + if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { + /* the following is not an error when doing bridging */ + if (!BRIDGE_TEST && rt->rt_ifp != ifp) { + if (log_arp_wrong_iface) + log(LOG_ERR, "arp: %s is on %s%d but got reply from %*D on %s%d\n", + inet_ntoa(isaddr), + rt->rt_ifp->if_name, rt->rt_ifp->if_unit, + ifp->if_addrlen, (u_char *)ar_sha(ah), ":", + ifp->if_name, ifp->if_unit); + goto reply; + } + if (sdl->sdl_alen && + bcmp(ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { + if (rt->rt_expire) { + if (log_arp_movements) + log(LOG_INFO, "arp: %s moved from %*D to %*D on %s%d\n", + inet_ntoa(isaddr), + ifp->if_addrlen, (u_char *)LLADDR(sdl), ":", + ifp->if_addrlen, (u_char *)ar_sha(ah), ":", + ifp->if_name, ifp->if_unit); + } else { + log(LOG_ERR, + "arp: %*D attempts to modify permanent entry for %s on %s%d\n", + ifp->if_addrlen, (u_char *)ar_sha(ah), ":", + inet_ntoa(isaddr), ifp->if_name, ifp->if_unit); + goto reply; + } + } + /* + * sanity check for the address length. + * XXX this does not work for protocols with variable address + * length. -is + */ + if (sdl->sdl_alen && + sdl->sdl_alen != ah->ar_hln) { + log(LOG_WARNING, + "arp from %*D: new addr len %d, was %d", + ifp->if_addrlen, (u_char *) ar_sha(ah), ":", + ah->ar_hln, sdl->sdl_alen); + } + if (ifp->if_addrlen != ah->ar_hln) { + log(LOG_WARNING, + "arp from %*D: addr len: new %d, i/f %d (ignored)", + ifp->if_addrlen, (u_char *) ar_sha(ah), ":", + ah->ar_hln, ifp->if_addrlen); + goto reply; + } + (void)memcpy(LLADDR(sdl), ar_sha(ah), + sdl->sdl_alen = ah->ar_hln); + /* + * If we receive an arp from a token-ring station over + * a token-ring nic then try to save the source + * routing info. + */ + if (ifp->if_type == IFT_ISO88025) { + th = (struct iso88025_header *)m->m_pkthdr.header; + trld = SDL_ISO88025(sdl); + rif_len = TR_RCF_RIFLEN(th->rcf); + if ((th->iso88025_shost[0] & TR_RII) && + (rif_len > 2)) { + trld->trld_rcf = th->rcf; + trld->trld_rcf ^= htons(TR_RCF_DIR); + memcpy(trld->trld_route, th->rd, rif_len - 2); + trld->trld_rcf &= ~htons(TR_RCF_BCST_MASK); + /* + * Set up source routing information for + * reply packet (XXX) + */ + m->m_data -= rif_len; + m->m_len += rif_len; + m->m_pkthdr.len += rif_len; + } else { + th->iso88025_shost[0] &= ~TR_RII; + trld->trld_rcf = 0; + } + m->m_data -= 8; + m->m_len += 8; + m->m_pkthdr.len += 8; + th->rcf = trld->trld_rcf; + } + if (rt->rt_expire) + rt->rt_expire = time_second + arpt_keep; + rt->rt_flags &= ~RTF_REJECT; + la->la_asked = 0; + if (la->la_hold) { + (*ifp->if_output)(ifp, la->la_hold, + rt_key(rt), rt); + la->la_hold = 0; + } + } +reply: + if (op != ARPOP_REQUEST) { + m_freem(m); + return; + } + if (itaddr.s_addr == myaddr.s_addr) { + /* I am the target */ + (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); + (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); + } else { + la = arplookup(itaddr.s_addr, 0, SIN_PROXY); + if (la == NULL) { + struct sockaddr_in sin; + + if (!arp_proxyall) { + m_freem(m); + return; + } + + bzero(&sin, sizeof sin); + sin.sin_family = AF_INET; + sin.sin_len = sizeof sin; + sin.sin_addr = itaddr; + + rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); + if (!rt) { + m_freem(m); + return; + } + /* + * 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 (rt->rt_ifp == ifp) { + rtfree(rt); + m_freem(m); + return; + } + (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); + (void)memcpy(ar_sha(ah), IF_LLADDR(ifp), ah->ar_hln); + rtfree(rt); + + /* + * Also check that the node which sent the ARP packet + * is on the the interface we expect it to be on. This + * avoids ARP chaos if an interface is connected to the + * wrong network. + */ + sin.sin_addr = isaddr; + + rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); + if (!rt) { + m_freem(m); + return; + } + if (rt->rt_ifp != ifp) { + log(LOG_INFO, "arp_proxy: ignoring request" + " from %s via %s%d, expecting %s%d\n", + inet_ntoa(isaddr), ifp->if_name, + ifp->if_unit, rt->rt_ifp->if_name, + rt->rt_ifp->if_unit); + rtfree(rt); + m_freem(m); + return; + } + rtfree(rt); + +#ifdef DEBUG_PROXY + printf("arp: proxying for %s\n", + inet_ntoa(itaddr)); +#endif + } else { + rt = la->la_rt; + (void)memcpy(ar_tha(ah), ar_sha(ah), ah->ar_hln); + sdl = SDL(rt->rt_gateway); + (void)memcpy(ar_sha(ah), LLADDR(sdl), ah->ar_hln); + } + } + + (void)memcpy(ar_tpa(ah), ar_spa(ah), ah->ar_pln); + (void)memcpy(ar_spa(ah), &itaddr, 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_ARCNET: + arh = (struct arc_header *)sa.sa_data; + arh->arc_dhost = *ar_tha(ah); + arh->arc_type = ARCTYPE_ARP; + break; + + case IFT_ISO88025: + /* Re-arrange the source/dest address */ + memcpy(th->iso88025_dhost, th->iso88025_shost, + sizeof(th->iso88025_dhost)); + memcpy(th->iso88025_shost, IF_LLADDR(ifp), + sizeof(th->iso88025_shost)); + /* Set the source routing bit if neccesary */ + if (th->iso88025_dhost[0] & TR_RII) { + th->iso88025_dhost[0] &= ~TR_RII; + if (TR_RCF_RIFLEN(th->rcf) > 2) + th->iso88025_shost[0] |= TR_RII; + } + /* Copy the addresses, ac and fc into sa_data */ + memcpy(sa.sa_data, th->iso88025_dhost, + sizeof(th->iso88025_dhost) * 2); + sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; + sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; + break; + case IFT_ETHER: + case IFT_FDDI: + /* + * May not be correct for types not explictly + * listed, but it is our best guess. + */ + default: + eh = (struct ether_header *)sa.sa_data; + (void)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, (struct rtentry *)0); + return; +} +#endif + +/* + * Free an arp entry. + */ +static void +arptfree(la) + register struct llinfo_arp *la; +{ + register struct rtentry *rt = la->la_rt; + register struct sockaddr_dl *sdl; + if (rt == 0) + panic("arptfree"); + if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && + sdl->sdl_family == AF_LINK) { + sdl->sdl_alen = 0; + la->la_asked = 0; + rt->rt_flags &= ~RTF_REJECT; + return; + } + rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), + 0, (struct rtentry **)0); +} +/* + * Lookup or enter a new address in arptab. + */ +static struct llinfo_arp * +arplookup(addr, create, proxy) + u_long addr; + int create, proxy; +{ + register struct rtentry *rt; + static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; + const char *why = 0; + + sin.sin_addr.s_addr = addr; + sin.sin_other = proxy ? SIN_PROXY : 0; + rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); + if (rt == 0) + return (0); + rt->rt_refcnt--; + + if (rt->rt_flags & RTF_GATEWAY) + why = "host is not on local network"; + else if ((rt->rt_flags & RTF_LLINFO) == 0) + why = "could not allocate llinfo"; + else if (rt->rt_gateway->sa_family != AF_LINK) + why = "gateway route is not ours"; + + if (why && create) { + log(LOG_DEBUG, "arplookup %s failed: %s\n", + inet_ntoa(sin.sin_addr), why); + return 0; + } else if (why) { + return 0; + } + return ((struct llinfo_arp *)rt->rt_llinfo); +} + +void +arp_ifinit(ifp, ifa) + struct ifnet *ifp; + struct ifaddr *ifa; +{ + if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) + arprequest(ifp, &IA_SIN(ifa)->sin_addr, + &IA_SIN(ifa)->sin_addr, IF_LLADDR(ifp)); + ifa->ifa_rtrequest = arp_rtrequest; + ifa->ifa_flags |= RTF_CLONING; +} + +static void +arp_init(void) +{ + + arpintrq.ifq_maxlen = 50; + mtx_init(&arpintrq.ifq_mtx, "arp_inq", NULL, MTX_DEF); + LIST_INIT(&llinfo_arp); + register_netisr(NETISR_ARP, arpintr); +} + +SYSINIT(arp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, arp_init, 0); |
