if_ether.c revision 39389
11541Srgrimes/* 21541Srgrimes * Copyright (c) 1982, 1986, 1988, 1993 31541Srgrimes * The Regents of the University of California. All rights reserved. 41541Srgrimes * 51541Srgrimes * Redistribution and use in source and binary forms, with or without 61541Srgrimes * modification, are permitted provided that the following conditions 71541Srgrimes * are met: 81541Srgrimes * 1. Redistributions of source code must retain the above copyright 91541Srgrimes * notice, this list of conditions and the following disclaimer. 101541Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111541Srgrimes * notice, this list of conditions and the following disclaimer in the 121541Srgrimes * documentation and/or other materials provided with the distribution. 131541Srgrimes * 3. All advertising materials mentioning features or use of this software 141541Srgrimes * must display the following acknowledgement: 151541Srgrimes * This product includes software developed by the University of 161541Srgrimes * California, Berkeley and its contributors. 171541Srgrimes * 4. Neither the name of the University nor the names of its contributors 181541Srgrimes * may be used to endorse or promote products derived from this software 191541Srgrimes * without specific prior written permission. 201541Srgrimes * 211541Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221541Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231541Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241541Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251541Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261541Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271541Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281541Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291541Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301541Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311541Srgrimes * SUCH DAMAGE. 321541Srgrimes * 331541Srgrimes * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 3439389Sfenner * $Id: if_ether.c,v 1.47 1998/06/12 03:48:14 julian Exp $ 351541Srgrimes */ 361541Srgrimes 371541Srgrimes/* 381541Srgrimes * Ethernet address resolution protocol. 391541Srgrimes * TODO: 401541Srgrimes * add "inuse/lock" bit (or ref. count) along with valid bit 411541Srgrimes */ 421541Srgrimes 4332350Seivind#include "opt_inet.h" 4432350Seivind 451541Srgrimes#include <sys/param.h> 4612693Sphk#include <sys/kernel.h> 4712693Sphk#include <sys/sysctl.h> 481541Srgrimes#include <sys/systm.h> 4912693Sphk#include <sys/mbuf.h> 501541Srgrimes#include <sys/malloc.h> 5118892Sbde#include <sys/socket.h> 521541Srgrimes#include <sys/syslog.h> 531541Srgrimes 541541Srgrimes#include <net/if.h> 551541Srgrimes#include <net/if_dl.h> 561541Srgrimes#include <net/route.h> 578426Swollman#include <net/netisr.h> 581541Srgrimes 591541Srgrimes#include <netinet/in.h> 601541Srgrimes#include <netinet/in_var.h> 611541Srgrimes#include <netinet/if_ether.h> 621541Srgrimes 631541Srgrimes#define SIN(s) ((struct sockaddr_in *)s) 641541Srgrimes#define SDL(s) ((struct sockaddr_dl *)s) 651541Srgrimes 6612942SwollmanSYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 671541Srgrimes 6812693Sphk/* timer values */ 6912942Swollmanstatic int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 7012942Swollmanstatic int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 7112942Swollmanstatic int arpt_down = 20; /* once declared down, don't send for 20 sec */ 721541Srgrimes 7312942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 7412942Swollman &arpt_prune, 0, ""); 7512942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 7612942Swollman &arpt_keep, 0, ""); 7712942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 7812942Swollman &arpt_down, 0, ""); 7912693Sphk 801541Srgrimes#define rt_expire rt_rmx.rmx_expire 811541Srgrimes 8211225Swollmanstruct llinfo_arp { 8311225Swollman LIST_ENTRY(llinfo_arp) la_le; 8411225Swollman struct rtentry *la_rt; 8511225Swollman struct mbuf *la_hold; /* last packet until resolved/timeout */ 8611225Swollman long la_asked; /* last time we QUERIED for this addr */ 8711225Swollman#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 8811225Swollman}; 8912693Sphk 9011225Swollmanstatic LIST_HEAD(, llinfo_arp) llinfo_arp; 9111225Swollman 921541Srgrimesstruct ifqueue arpintrq = {0, 0, 0, 50}; 9312820Sphkstatic int arp_inuse, arp_allocated; 941541Srgrimes 9512693Sphkstatic int arp_maxtries = 5; 9612942Swollmanstatic int useloopback = 1; /* use loopback interface for local traffic */ 9712942Swollmanstatic int arp_proxyall = 0; 983282Swollman 9912942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 10012942Swollman &arp_maxtries, 0, ""); 10112942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 10212942Swollman &useloopback, 0, ""); 10312942SwollmanSYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 10412942Swollman &arp_proxyall, 0, ""); 10512693Sphk 10612877Sbdestatic void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 10736908Sjulianstatic void arprequest __P((struct arpcom *, 10836908Sjulian struct in_addr *, struct in_addr *, u_char *)); 10912693Sphkstatic void arpintr __P((void)); 11012693Sphkstatic void arptfree __P((struct llinfo_arp *)); 11112693Sphkstatic void arptimer __P((void *)); 11212693Sphkstatic struct llinfo_arp 11312693Sphk *arplookup __P((u_long, int, int)); 11432350Seivind#ifdef INET 11512693Sphkstatic void in_arpinput __P((struct mbuf *)); 11632350Seivind#endif 11712693Sphk 1181541Srgrimes/* 1191541Srgrimes * Timeout routine. Age arp_tab entries periodically. 1201541Srgrimes */ 1211541Srgrimes/* ARGSUSED */ 1221541Srgrimesstatic void 1231541Srgrimesarptimer(ignored_arg) 1241541Srgrimes void *ignored_arg; 1251541Srgrimes{ 1261541Srgrimes int s = splnet(); 12711225Swollman register struct llinfo_arp *la = llinfo_arp.lh_first; 12811225Swollman struct llinfo_arp *ola; 1291541Srgrimes 1301541Srgrimes timeout(arptimer, (caddr_t)0, arpt_prune * hz); 13111225Swollman while ((ola = la) != 0) { 1321541Srgrimes register struct rtentry *rt = la->la_rt; 13311225Swollman la = la->la_le.le_next; 13434961Sphk if (rt->rt_expire && rt->rt_expire <= time_second) 13511225Swollman arptfree(ola); /* timer has expired, clear */ 1361541Srgrimes } 1371541Srgrimes splx(s); 1381541Srgrimes} 1391541Srgrimes 1401541Srgrimes/* 1411541Srgrimes * Parallel to llc_rtrequest. 1421541Srgrimes */ 1435196Swollmanstatic void 1441541Srgrimesarp_rtrequest(req, rt, sa) 1451541Srgrimes int req; 1461541Srgrimes register struct rtentry *rt; 1471541Srgrimes struct sockaddr *sa; 1481541Srgrimes{ 1491541Srgrimes register struct sockaddr *gate = rt->rt_gateway; 1501541Srgrimes register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 1511541Srgrimes static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 15212693Sphk static int arpinit_done; 1531541Srgrimes 1541541Srgrimes if (!arpinit_done) { 1551541Srgrimes arpinit_done = 1; 15611225Swollman LIST_INIT(&llinfo_arp); 1571541Srgrimes timeout(arptimer, (caddr_t)0, hz); 1581541Srgrimes } 1591541Srgrimes if (rt->rt_flags & RTF_GATEWAY) 1601541Srgrimes return; 1611541Srgrimes switch (req) { 1621541Srgrimes 1631541Srgrimes case RTM_ADD: 1641541Srgrimes /* 1651541Srgrimes * XXX: If this is a manually added route to interface 1661541Srgrimes * such as older version of routed or gated might provide, 1671541Srgrimes * restore cloning bit. 1681541Srgrimes */ 1691541Srgrimes if ((rt->rt_flags & RTF_HOST) == 0 && 1701541Srgrimes SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 1711541Srgrimes rt->rt_flags |= RTF_CLONING; 1721541Srgrimes if (rt->rt_flags & RTF_CLONING) { 1731541Srgrimes /* 1741541Srgrimes * Case 1: This route should come from a route to iface. 1751541Srgrimes */ 1761541Srgrimes rt_setgate(rt, rt_key(rt), 1771541Srgrimes (struct sockaddr *)&null_sdl); 1781541Srgrimes gate = rt->rt_gateway; 1791541Srgrimes SDL(gate)->sdl_type = rt->rt_ifp->if_type; 1801541Srgrimes SDL(gate)->sdl_index = rt->rt_ifp->if_index; 18134961Sphk rt->rt_expire = time_second; 1821541Srgrimes break; 1831541Srgrimes } 1841541Srgrimes /* Announce a new entry if requested. */ 1851541Srgrimes if (rt->rt_flags & RTF_ANNOUNCE) 1861541Srgrimes arprequest((struct arpcom *)rt->rt_ifp, 18736908Sjulian &SIN(rt_key(rt))->sin_addr, 18836908Sjulian &SIN(rt_key(rt))->sin_addr, 1891541Srgrimes (u_char *)LLADDR(SDL(gate))); 1901541Srgrimes /*FALLTHROUGH*/ 1911541Srgrimes case RTM_RESOLVE: 1921541Srgrimes if (gate->sa_family != AF_LINK || 1931541Srgrimes gate->sa_len < sizeof(null_sdl)) { 1946568Sdg log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 1951541Srgrimes break; 1961541Srgrimes } 1971541Srgrimes SDL(gate)->sdl_type = rt->rt_ifp->if_type; 1981541Srgrimes SDL(gate)->sdl_index = rt->rt_ifp->if_index; 1991541Srgrimes if (la != 0) 2001541Srgrimes break; /* This happens on a route change */ 2011541Srgrimes /* 2021541Srgrimes * Case 2: This route may come from cloning, or a manual route 2031541Srgrimes * add with a LL address. 2041541Srgrimes */ 2051541Srgrimes R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 2061541Srgrimes rt->rt_llinfo = (caddr_t)la; 2071541Srgrimes if (la == 0) { 2081541Srgrimes log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 2091541Srgrimes break; 2101541Srgrimes } 2111541Srgrimes arp_inuse++, arp_allocated++; 2121541Srgrimes Bzero(la, sizeof(*la)); 2131541Srgrimes la->la_rt = rt; 2141541Srgrimes rt->rt_flags |= RTF_LLINFO; 21511225Swollman LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 21613926Swollman 21732350Seivind#ifdef INET 21813926Swollman /* 21913926Swollman * This keeps the multicast addresses from showing up 22013926Swollman * in `arp -a' listings as unresolved. It's not actually 22113926Swollman * functional. Then the same for broadcast. 22213926Swollman */ 22313926Swollman if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 22413926Swollman ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 22513926Swollman LLADDR(SDL(gate))); 22613926Swollman SDL(gate)->sdl_alen = 6; 22716576Speter rt->rt_expire = 0; 22813926Swollman } 22913926Swollman if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 23013926Swollman memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 23113926Swollman SDL(gate)->sdl_alen = 6; 23216576Speter rt->rt_expire = 0; 23313926Swollman } 23432350Seivind#endif 23513926Swollman 2361541Srgrimes if (SIN(rt_key(rt))->sin_addr.s_addr == 2371541Srgrimes (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 2381541Srgrimes /* 2391541Srgrimes * This test used to be 2401541Srgrimes * if (loif.if_flags & IFF_UP) 2411541Srgrimes * It allowed local traffic to be forced 2421541Srgrimes * through the hardware by configuring the loopback down. 2431541Srgrimes * However, it causes problems during network configuration 2441541Srgrimes * for boards that can't receive packets they send. 2451541Srgrimes * It is now necessary to clear "useloopback" and remove 2461541Srgrimes * the route to force traffic out to the hardware. 2471541Srgrimes */ 2481541Srgrimes rt->rt_expire = 0; 2491541Srgrimes Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 2501541Srgrimes LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 2511541Srgrimes if (useloopback) 2528090Spst rt->rt_ifp = loif; 2531541Srgrimes 2541541Srgrimes } 2551541Srgrimes break; 2561541Srgrimes 2571541Srgrimes case RTM_DELETE: 2581541Srgrimes if (la == 0) 2591541Srgrimes break; 2601541Srgrimes arp_inuse--; 26111225Swollman LIST_REMOVE(la, la_le); 2621541Srgrimes rt->rt_llinfo = 0; 2631541Srgrimes rt->rt_flags &= ~RTF_LLINFO; 2641541Srgrimes if (la->la_hold) 2651541Srgrimes m_freem(la->la_hold); 2661541Srgrimes Free((caddr_t)la); 2671541Srgrimes } 2681541Srgrimes} 2691541Srgrimes 2701541Srgrimes/* 2711541Srgrimes * Broadcast an ARP request. Caller specifies: 2721541Srgrimes * - arp header source ip address 2731541Srgrimes * - arp header target ip address 2741541Srgrimes * - arp header source ethernet address 2751541Srgrimes */ 2761541Srgrimesstatic void 2771541Srgrimesarprequest(ac, sip, tip, enaddr) 2781541Srgrimes register struct arpcom *ac; 27936908Sjulian register struct in_addr *sip, *tip; 2801541Srgrimes register u_char *enaddr; 2811541Srgrimes{ 2821541Srgrimes register struct mbuf *m; 2831541Srgrimes register struct ether_header *eh; 2841541Srgrimes register struct ether_arp *ea; 2851541Srgrimes struct sockaddr sa; 2861541Srgrimes 2871541Srgrimes if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 2881541Srgrimes return; 2891541Srgrimes m->m_len = sizeof(*ea); 2901541Srgrimes m->m_pkthdr.len = sizeof(*ea); 2911541Srgrimes MH_ALIGN(m, sizeof(*ea)); 2921541Srgrimes ea = mtod(m, struct ether_arp *); 2931541Srgrimes eh = (struct ether_header *)sa.sa_data; 2941541Srgrimes bzero((caddr_t)ea, sizeof (*ea)); 2958384Sdg (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 29616341Sdg eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 2971541Srgrimes ea->arp_hrd = htons(ARPHRD_ETHER); 2981541Srgrimes ea->arp_pro = htons(ETHERTYPE_IP); 2991541Srgrimes ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 3001541Srgrimes ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 3011541Srgrimes ea->arp_op = htons(ARPOP_REQUEST); 3028384Sdg (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 3038384Sdg (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 3048384Sdg (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 3051541Srgrimes sa.sa_family = AF_UNSPEC; 3061541Srgrimes sa.sa_len = sizeof(sa); 3071541Srgrimes (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 3081541Srgrimes} 3091541Srgrimes 3101541Srgrimes/* 3111541Srgrimes * Resolve an IP address into an ethernet address. If success, 3121541Srgrimes * desten is filled in. If there is no entry in arptab, 3131541Srgrimes * set one up and broadcast a request for the IP address. 3141541Srgrimes * Hold onto this mbuf and resend it once the address 3151541Srgrimes * is finally resolved. A return value of 1 indicates 3161541Srgrimes * that desten has been filled in and the packet should be sent 3171541Srgrimes * normally; a 0 return indicates that the packet has been 3181541Srgrimes * taken over here, either now or for later transmission. 3191541Srgrimes */ 3201541Srgrimesint 3213514Swollmanarpresolve(ac, rt, m, dst, desten, rt0) 3221541Srgrimes register struct arpcom *ac; 3231541Srgrimes register struct rtentry *rt; 3241541Srgrimes struct mbuf *m; 3251541Srgrimes register struct sockaddr *dst; 3261541Srgrimes register u_char *desten; 3273514Swollman struct rtentry *rt0; 3281541Srgrimes{ 3291541Srgrimes register struct llinfo_arp *la; 3301541Srgrimes struct sockaddr_dl *sdl; 3311541Srgrimes 3321541Srgrimes if (m->m_flags & M_BCAST) { /* broadcast */ 3338384Sdg (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 3341541Srgrimes return (1); 3351541Srgrimes } 3361541Srgrimes if (m->m_flags & M_MCAST) { /* multicast */ 3371541Srgrimes ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 3381541Srgrimes return(1); 3391541Srgrimes } 3401541Srgrimes if (rt) 3411541Srgrimes la = (struct llinfo_arp *)rt->rt_llinfo; 3421541Srgrimes else { 3433311Sphk la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 3443311Sphk if (la) 3451541Srgrimes rt = la->la_rt; 3461541Srgrimes } 3471541Srgrimes if (la == 0 || rt == 0) { 34836308Sphk log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 34936308Sphk inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 35036308Sphk rt ? "rt" : ""); 3511541Srgrimes m_freem(m); 3521541Srgrimes return (0); 3531541Srgrimes } 3541541Srgrimes sdl = SDL(rt->rt_gateway); 3551541Srgrimes /* 3561541Srgrimes * Check the address family and length is valid, the address 3571541Srgrimes * is resolved; otherwise, try to resolve. 3581541Srgrimes */ 35934961Sphk if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 3601541Srgrimes sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 36116206Sbde bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 3621541Srgrimes return 1; 3631541Srgrimes } 3641541Srgrimes /* 3651541Srgrimes * There is an arptab entry, but no ethernet address 3661541Srgrimes * response yet. Replace the held mbuf with this 3671541Srgrimes * latest one. 3681541Srgrimes */ 3691541Srgrimes if (la->la_hold) 3701541Srgrimes m_freem(la->la_hold); 3711541Srgrimes la->la_hold = m; 3721541Srgrimes if (rt->rt_expire) { 3731541Srgrimes rt->rt_flags &= ~RTF_REJECT; 37434961Sphk if (la->la_asked == 0 || rt->rt_expire != time_second) { 37534961Sphk rt->rt_expire = time_second; 3761541Srgrimes if (la->la_asked++ < arp_maxtries) 37714761Sfenner arprequest(ac, 37836908Sjulian &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 37936908Sjulian &SIN(dst)->sin_addr, ac->ac_enaddr); 3801541Srgrimes else { 3811541Srgrimes rt->rt_flags |= RTF_REJECT; 3821541Srgrimes rt->rt_expire += arpt_down; 3831541Srgrimes la->la_asked = 0; 3841541Srgrimes } 3851541Srgrimes 3861541Srgrimes } 3871541Srgrimes } 3881541Srgrimes return (0); 3891541Srgrimes} 3901541Srgrimes 3911541Srgrimes/* 3921541Srgrimes * Common length and type checks are done here, 3931541Srgrimes * then the protocol-specific routine is called. 3941541Srgrimes */ 39512693Sphkstatic void 39631884Sbdearpintr() 3971541Srgrimes{ 3981541Srgrimes register struct mbuf *m; 3991541Srgrimes register struct arphdr *ar; 4001541Srgrimes int s; 4011541Srgrimes 4021541Srgrimes while (arpintrq.ifq_head) { 4031541Srgrimes s = splimp(); 4041541Srgrimes IF_DEQUEUE(&arpintrq, m); 4051541Srgrimes splx(s); 4061541Srgrimes if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 4071541Srgrimes panic("arpintr"); 4081541Srgrimes if (m->m_len >= sizeof(struct arphdr) && 4091541Srgrimes (ar = mtod(m, struct arphdr *)) && 4101541Srgrimes ntohs(ar->ar_hrd) == ARPHRD_ETHER && 4111541Srgrimes m->m_len >= 4121541Srgrimes sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 4131541Srgrimes 4141541Srgrimes switch (ntohs(ar->ar_pro)) { 4151541Srgrimes 41632350Seivind#ifdef INET 4171541Srgrimes case ETHERTYPE_IP: 4181541Srgrimes in_arpinput(m); 4191541Srgrimes continue; 42032350Seivind#endif 4211541Srgrimes } 4221541Srgrimes m_freem(m); 4231541Srgrimes } 4241541Srgrimes} 4251541Srgrimes 4268426SwollmanNETISR_SET(NETISR_ARP, arpintr); 4278426Swollman 42832350Seivind 42932350Seivind#ifdef INET 4301541Srgrimes/* 4311541Srgrimes * ARP for Internet protocols on 10 Mb/s Ethernet. 4321541Srgrimes * Algorithm is that given in RFC 826. 4331541Srgrimes * In addition, a sanity check is performed on the sender 4341541Srgrimes * protocol address, to catch impersonators. 4351541Srgrimes * We no longer handle negotiations for use of trailer protocol: 4361541Srgrimes * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 4371541Srgrimes * along with IP replies if we wanted trailers sent to us, 4381541Srgrimes * and also sent them in response to IP replies. 4391541Srgrimes * This allowed either end to announce the desire to receive 4401541Srgrimes * trailer packets. 4411541Srgrimes * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 4421541Srgrimes * but formerly didn't normally send requests. 4431541Srgrimes */ 4441541Srgrimesstatic void 4451541Srgrimesin_arpinput(m) 4461541Srgrimes struct mbuf *m; 4471541Srgrimes{ 4481541Srgrimes register struct ether_arp *ea; 4491541Srgrimes register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 4501541Srgrimes struct ether_header *eh; 4511541Srgrimes register struct llinfo_arp *la = 0; 4521541Srgrimes register struct rtentry *rt; 4531541Srgrimes struct in_ifaddr *ia, *maybe_ia = 0; 4541541Srgrimes struct sockaddr_dl *sdl; 4551541Srgrimes struct sockaddr sa; 4561541Srgrimes struct in_addr isaddr, itaddr, myaddr; 4571541Srgrimes int op; 4581541Srgrimes 4591541Srgrimes ea = mtod(m, struct ether_arp *); 4601541Srgrimes op = ntohs(ea->arp_op); 4618384Sdg (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 4628384Sdg (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 46320525Sbde for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 4641541Srgrimes if (ia->ia_ifp == &ac->ac_if) { 4651541Srgrimes maybe_ia = ia; 4661541Srgrimes if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 4671541Srgrimes (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 4681541Srgrimes break; 4691541Srgrimes } 47012693Sphk if (maybe_ia == 0) { 47112693Sphk m_freem(m); 47212693Sphk return; 47312693Sphk } 4741541Srgrimes myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 4751541Srgrimes if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 47612693Sphk sizeof (ea->arp_sha))) { 47712693Sphk m_freem(m); /* it's from me, ignore it. */ 47812693Sphk return; 47912693Sphk } 4801541Srgrimes if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 4811541Srgrimes sizeof (ea->arp_sha))) { 4821541Srgrimes log(LOG_ERR, 4834069Swollman "arp: ether address is broadcast for IP address %s!\n", 4847088Swollman inet_ntoa(isaddr)); 48512693Sphk m_freem(m); 48612693Sphk return; 4871541Srgrimes } 4881541Srgrimes if (isaddr.s_addr == myaddr.s_addr) { 4891541Srgrimes log(LOG_ERR, 49019794Sfenner "arp: %6D is using my IP address %s!\n", 49119794Sfenner ea->arp_sha, ":", inet_ntoa(isaddr)); 4921541Srgrimes itaddr = myaddr; 4931541Srgrimes goto reply; 4941541Srgrimes } 4951541Srgrimes la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 4961541Srgrimes if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 49739389Sfenner if (rt->rt_ifp != &ac->ac_if) { 49839389Sfenner log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 49939389Sfenner inet_ntoa(isaddr), 50039389Sfenner rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 50139389Sfenner ea->arp_sha, ":", 50239389Sfenner ac->ac_if.if_name, ac->ac_if.if_unit); 50339389Sfenner goto reply; 50439389Sfenner } 5051541Srgrimes if (sdl->sdl_alen && 5061541Srgrimes bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 50739389Sfenner if (rt->rt_expire) 50839389Sfenner log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 50939389Sfenner inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 51039389Sfenner ea->arp_sha, ":", 51139389Sfenner ac->ac_if.if_name, ac->ac_if.if_unit); 51239389Sfenner else { 51339389Sfenner log(LOG_ERR, 51439389Sfenner "arp: %6D attempts to modify permanent entry for %s on %s%d", 51539389Sfenner ea->arp_sha, ":", inet_ntoa(isaddr), 51639389Sfenner ac->ac_if.if_name, ac->ac_if.if_unit); 51739389Sfenner goto reply; 51839389Sfenner } 5198384Sdg (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 5208384Sdg sdl->sdl_alen = sizeof(ea->arp_sha); 5211541Srgrimes if (rt->rt_expire) 52234961Sphk rt->rt_expire = time_second + arpt_keep; 5231541Srgrimes rt->rt_flags &= ~RTF_REJECT; 5241541Srgrimes la->la_asked = 0; 5251541Srgrimes if (la->la_hold) { 5261541Srgrimes (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 5271541Srgrimes rt_key(rt), rt); 5281541Srgrimes la->la_hold = 0; 5291541Srgrimes } 5301541Srgrimes } 5311541Srgrimesreply: 5321541Srgrimes if (op != ARPOP_REQUEST) { 5331541Srgrimes m_freem(m); 5341541Srgrimes return; 5351541Srgrimes } 5361541Srgrimes if (itaddr.s_addr == myaddr.s_addr) { 5371541Srgrimes /* I am the target */ 5388384Sdg (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 5398384Sdg (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 5401541Srgrimes } else { 5411541Srgrimes la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 5423282Swollman if (la == NULL) { 5433282Swollman struct sockaddr_in sin; 5443282Swollman 54512693Sphk if (!arp_proxyall) { 54612693Sphk m_freem(m); 54712693Sphk return; 54812693Sphk } 5493282Swollman 5503282Swollman bzero(&sin, sizeof sin); 5513282Swollman sin.sin_family = AF_INET; 5523282Swollman sin.sin_len = sizeof sin; 5533282Swollman sin.sin_addr = itaddr; 5543282Swollman 5555101Swollman rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 55612693Sphk if (!rt) { 55712693Sphk m_freem(m); 55812693Sphk return; 55912693Sphk } 5603282Swollman /* 5613282Swollman * Don't send proxies for nodes on the same interface 5623282Swollman * as this one came out of, or we'll get into a fight 5633282Swollman * over who claims what Ether address. 5643282Swollman */ 56512693Sphk if (rt->rt_ifp == &ac->ac_if) { 5663282Swollman rtfree(rt); 56712693Sphk m_freem(m); 56812693Sphk return; 5693282Swollman } 5708384Sdg (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 5718384Sdg (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 5723282Swollman rtfree(rt); 5734069Swollman#ifdef DEBUG_PROXY 5748876Srgrimes printf("arp: proxying for %s\n", 5757088Swollman inet_ntoa(itaddr)); 5764069Swollman#endif 5773282Swollman } else { 5783282Swollman rt = la->la_rt; 5798384Sdg (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 5803282Swollman sdl = SDL(rt->rt_gateway); 5818384Sdg (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 5823282Swollman } 5831541Srgrimes } 5841541Srgrimes 5858384Sdg (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 5868384Sdg (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 5871541Srgrimes ea->arp_op = htons(ARPOP_REPLY); 5881541Srgrimes ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 5891541Srgrimes eh = (struct ether_header *)sa.sa_data; 5908384Sdg (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 59116341Sdg eh->ether_type = htons(ETHERTYPE_ARP); 5921541Srgrimes sa.sa_family = AF_UNSPEC; 5931541Srgrimes sa.sa_len = sizeof(sa); 5941541Srgrimes (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 5951541Srgrimes return; 5961541Srgrimes} 59732350Seivind#endif 5981541Srgrimes 5991541Srgrimes/* 6001541Srgrimes * Free an arp entry. 6011541Srgrimes */ 6021541Srgrimesstatic void 6031541Srgrimesarptfree(la) 6041541Srgrimes register struct llinfo_arp *la; 6051541Srgrimes{ 6061541Srgrimes register struct rtentry *rt = la->la_rt; 6071541Srgrimes register struct sockaddr_dl *sdl; 6081541Srgrimes if (rt == 0) 6091541Srgrimes panic("arptfree"); 6101541Srgrimes if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 6111541Srgrimes sdl->sdl_family == AF_LINK) { 6121541Srgrimes sdl->sdl_alen = 0; 6131541Srgrimes la->la_asked = 0; 6141541Srgrimes rt->rt_flags &= ~RTF_REJECT; 6151541Srgrimes return; 6161541Srgrimes } 6171541Srgrimes rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 6181541Srgrimes 0, (struct rtentry **)0); 6191541Srgrimes} 6201541Srgrimes/* 6211541Srgrimes * Lookup or enter a new address in arptab. 6221541Srgrimes */ 6231541Srgrimesstatic struct llinfo_arp * 6241541Srgrimesarplookup(addr, create, proxy) 6251541Srgrimes u_long addr; 6261541Srgrimes int create, proxy; 6271541Srgrimes{ 6281541Srgrimes register struct rtentry *rt; 6291541Srgrimes static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 6304069Swollman const char *why = 0; 6311541Srgrimes 6321541Srgrimes sin.sin_addr.s_addr = addr; 6331541Srgrimes sin.sin_other = proxy ? SIN_PROXY : 0; 6345101Swollman rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 6351541Srgrimes if (rt == 0) 6361541Srgrimes return (0); 6371541Srgrimes rt->rt_refcnt--; 6384069Swollman 63912693Sphk if (rt->rt_flags & RTF_GATEWAY) 6404069Swollman why = "host is not on local network"; 64112693Sphk else if ((rt->rt_flags & RTF_LLINFO) == 0) 6424069Swollman why = "could not allocate llinfo"; 64312693Sphk else if (rt->rt_gateway->sa_family != AF_LINK) 6444069Swollman why = "gateway route is not ours"; 6454069Swollman 64612693Sphk if (why && create) { 6474069Swollman log(LOG_DEBUG, "arplookup %s failed: %s\n", 6487088Swollman inet_ntoa(sin.sin_addr), why); 6494069Swollman return 0; 65012693Sphk } else if (why) { 6514069Swollman return 0; 6521541Srgrimes } 6531541Srgrimes return ((struct llinfo_arp *)rt->rt_llinfo); 6541541Srgrimes} 6551541Srgrimes 6565195Swollmanvoid 6575195Swollmanarp_ifinit(ac, ifa) 6585195Swollman struct arpcom *ac; 6595195Swollman struct ifaddr *ifa; 6605195Swollman{ 66125822Stegge if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 66236908Sjulian arprequest(ac, &IA_SIN(ifa)->sin_addr, 66336908Sjulian &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 6645195Swollman ifa->ifa_rtrequest = arp_rtrequest; 6655195Swollman ifa->ifa_flags |= RTF_CLONING; 6665195Swollman} 667