1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)if_ether.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD$ 35 */ 36 37 /* 38 * Ethernet address resolution protocol. 39 * TODO: 40 * add "inuse/lock" bit (or ref. count) along with valid bit 41 */ 42 43 #include "opt_inet.h" 44 #include "opt_bdg.h" 45 46 #include <sys/param.h> 47 #include <sys/kernel.h> 48 #include <sys/queue.h> 49 #include <sys/sysctl.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/malloc.h> 53 #include <sys/socket.h> 54 #include <sys/syslog.h> 55 56 #include <net/if.h> 57 #include <net/if_dl.h> 58 #include <net/if_types.h> 59 #include <net/route.h> 60 #include <net/netisr.h> 61 #include <net/if_llc.h> 62 63 #include <netinet/in.h> 64 #include <netinet/in_var.h> 65 #include <netinet/if_ether.h> 66 67 #include <net/iso88025.h> 68 69 #define SIN(s) ((struct sockaddr_in *)s) 70 #define SDL(s) ((struct sockaddr_dl *)s) 71 72 SYSCTL_DECL(_net_link_ether); 73 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 74 75 /* timer values */ 76 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 77 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 78 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 79 80 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 81 &arpt_prune, 0, ""); 82 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 83 &arpt_keep, 0, ""); 84 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 85 &arpt_down, 0, ""); 86 87 #define rt_expire rt_rmx.rmx_expire 88 89 struct llinfo_arp { 90 LIST_ENTRY(llinfo_arp) la_le; 91 struct rtentry *la_rt; 92 struct mbuf *la_hold; /* last packet until resolved/timeout */ 93 long la_asked; /* last time we QUERIED for this addr */ 94 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 95 }; 96 97 static LIST_HEAD(, llinfo_arp) llinfo_arp; 98 99 struct ifqueue arpintrq = {0, 0, 0, 50}; 100 static int arp_inuse, arp_allocated; 101 102 static int arp_maxtries = 5; 103 static int useloopback = 1; /* use loopback interface for local traffic */ 104 static int arp_proxyall = 0; 105 106 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 107 &arp_maxtries, 0, ""); 108 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 109 &useloopback, 0, ""); 110 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 111 &arp_proxyall, 0, ""); 112 113 static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 114 static void arprequest __P((struct arpcom *, 115 struct in_addr *, struct in_addr *, u_char *)); 116 static void arpintr __P((void)); 117 static void arptfree __P((struct llinfo_arp *)); 118 static void arptimer __P((void *)); 119 static struct llinfo_arp 120 *arplookup __P((u_long, int, int)); 121 #ifdef INET 122 static void in_arpinput __P((struct mbuf *)); 123 #endif 124 125 /* 126 * Timeout routine. Age arp_tab entries periodically. 127 */ 128 /* ARGSUSED */ 129 static void 130 arptimer(ignored_arg) 131 void *ignored_arg; 132 { 133 int s = splnet(); 134 register struct llinfo_arp *la = llinfo_arp.lh_first; 135 struct llinfo_arp *ola; 136 137 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 138 while ((ola = la) != 0) { 139 register struct rtentry *rt = la->la_rt; 140 la = la->la_le.le_next; 141 if (rt->rt_expire && rt->rt_expire <= time_second) 142 arptfree(ola); /* timer has expired, clear */ 143 } 144 splx(s); 145 } 146 147 /* 148 * Parallel to llc_rtrequest. 149 */ 150 static void 151 arp_rtrequest(req, rt, sa) 152 int req; 153 register struct rtentry *rt; 154 struct sockaddr *sa; 155 { 156 register struct sockaddr *gate = rt->rt_gateway; 157 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 158 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 159 static int arpinit_done; 160 161 if (!arpinit_done) { 162 arpinit_done = 1; 163 LIST_INIT(&llinfo_arp); 164 timeout(arptimer, (caddr_t)0, hz); 165 register_netisr(NETISR_ARP, arpintr); 166 } 167 if (rt->rt_flags & RTF_GATEWAY) 168 return; 169 switch (req) { 170 171 case RTM_ADD: 172 /* 173 * XXX: If this is a manually added route to interface 174 * such as older version of routed or gated might provide, 175 * restore cloning bit. 176 */ 177 if ((rt->rt_flags & RTF_HOST) == 0 && 178 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 179 rt->rt_flags |= RTF_CLONING; 180 if (rt->rt_flags & RTF_CLONING) { 181 /* 182 * Case 1: This route should come from a route to iface. 183 */ 184 rt_setgate(rt, rt_key(rt), 185 (struct sockaddr *)&null_sdl); 186 gate = rt->rt_gateway; 187 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 188 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 189 rt->rt_expire = time_second; 190 break; 191 } 192 /* Announce a new entry if requested. */ 193 if (rt->rt_flags & RTF_ANNOUNCE) 194 arprequest((struct arpcom *)rt->rt_ifp, 195 &SIN(rt_key(rt))->sin_addr, 196 &SIN(rt_key(rt))->sin_addr, 197 (u_char *)LLADDR(SDL(gate))); 198 /*FALLTHROUGH*/ 199 case RTM_RESOLVE: 200 if (gate->sa_family != AF_LINK || 201 gate->sa_len < sizeof(null_sdl)) { 202 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 203 break; 204 } 205 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 206 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 207 if (la != 0) 208 break; /* This happens on a route change */ 209 /* 210 * Case 2: This route may come from cloning, or a manual route 211 * add with a LL address. 212 */ 213 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 214 rt->rt_llinfo = (caddr_t)la; 215 if (la == 0) { 216 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 217 break; 218 } 219 arp_inuse++, arp_allocated++; 220 Bzero(la, sizeof(*la)); 221 la->la_rt = rt; 222 rt->rt_flags |= RTF_LLINFO; 223 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 224 225 #ifdef INET 226 /* 227 * This keeps the multicast addresses from showing up 228 * in `arp -a' listings as unresolved. It's not actually 229 * functional. Then the same for broadcast. 230 */ 231 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 232 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 233 LLADDR(SDL(gate))); 234 SDL(gate)->sdl_alen = 6; 235 rt->rt_expire = 0; 236 } 237 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 238 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 239 SDL(gate)->sdl_alen = 6; 240 rt->rt_expire = 0; 241 } 242 #endif 243 244 if (SIN(rt_key(rt))->sin_addr.s_addr == 245 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 246 /* 247 * This test used to be 248 * if (loif.if_flags & IFF_UP) 249 * It allowed local traffic to be forced 250 * through the hardware by configuring the loopback down. 251 * However, it causes problems during network configuration 252 * for boards that can't receive packets they send. 253 * It is now necessary to clear "useloopback" and remove 254 * the route to force traffic out to the hardware. 255 */ 256 rt->rt_expire = 0; 257 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 258 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 259 if (useloopback) 260 rt->rt_ifp = loif; 261 262 } 263 break; 264 265 case RTM_DELETE: 266 if (la == 0) 267 break; 268 arp_inuse--; 269 LIST_REMOVE(la, la_le); 270 rt->rt_llinfo = 0; 271 rt->rt_flags &= ~RTF_LLINFO; 272 if (la->la_hold) 273 m_freem(la->la_hold); 274 Free((caddr_t)la); 275 } 276 } 277 278 /* 279 * Broadcast an ARP request. Caller specifies: 280 * - arp header source ip address 281 * - arp header target ip address 282 * - arp header source ethernet address 283 */ 284 static void 285 arprequest(ac, sip, tip, enaddr) 286 register struct arpcom *ac; 287 register struct in_addr *sip, *tip; 288 register u_char *enaddr; 289 { 290 register struct mbuf *m; 291 register struct ether_header *eh; 292 register struct ether_arp *ea; 293 struct sockaddr sa; 294 static u_char llcx[] = { 0x82, 0x40, LLC_SNAP_LSAP, LLC_SNAP_LSAP, 295 LLC_UI, 0x00, 0x00, 0x00, 0x08, 0x06 }; 296 297 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 298 return; 299 m->m_pkthdr.rcvif = (struct ifnet *)0; 300 switch (ac->ac_if.if_type) { 301 case IFT_ISO88025: 302 m->m_len = sizeof(*ea) + sizeof(llcx); 303 m->m_pkthdr.len = sizeof(*ea) + sizeof(llcx); 304 MH_ALIGN(m, sizeof(*ea) + sizeof(llcx)); 305 (void)memcpy(mtod(m, caddr_t), llcx, sizeof(llcx)); 306 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 307 (void)memcpy(sa.sa_data + 6, enaddr, 6); 308 sa.sa_data[6] |= TR_RII; 309 sa.sa_data[12] = TR_AC; 310 sa.sa_data[13] = TR_LLC_FRAME; 311 ea = (struct ether_arp *)(mtod(m, char *) + sizeof(llcx)); 312 bzero((caddr_t)ea, sizeof (*ea)); 313 ea->arp_hrd = htons(ARPHRD_IEEE802); 314 break; 315 case IFT_FDDI: 316 case IFT_ETHER: 317 /* 318 * This may not be correct for types not explicitly 319 * listed, but this is our best guess 320 */ 321 default: 322 m->m_len = sizeof(*ea); 323 m->m_pkthdr.len = sizeof(*ea); 324 MH_ALIGN(m, sizeof(*ea)); 325 ea = mtod(m, struct ether_arp *); 326 eh = (struct ether_header *)sa.sa_data; 327 bzero((caddr_t)ea, sizeof (*ea)); 328 /* if_output will not swap */ 329 eh->ether_type = htons(ETHERTYPE_ARP); 330 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 331 sizeof(eh->ether_dhost)); 332 ea->arp_hrd = htons(ARPHRD_ETHER); 333 break; 334 } 335 ea->arp_pro = htons(ETHERTYPE_IP); 336 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 337 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 338 ea->arp_op = htons(ARPOP_REQUEST); 339 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 340 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 341 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 342 sa.sa_family = AF_UNSPEC; 343 sa.sa_len = sizeof(sa); 344 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 345 } 346 347 /* 348 * Resolve an IP address into an ethernet address. If success, 349 * desten is filled in. If there is no entry in arptab, 350 * set one up and broadcast a request for the IP address. 351 * Hold onto this mbuf and resend it once the address 352 * is finally resolved. A return value of 1 indicates 353 * that desten has been filled in and the packet should be sent 354 * normally; a 0 return indicates that the packet has been 355 * taken over here, either now or for later transmission. 356 */ 357 int 358 arpresolve(ac, rt, m, dst, desten, rt0) 359 register struct arpcom *ac; 360 register struct rtentry *rt; 361 struct mbuf *m; 362 register struct sockaddr *dst; 363 register u_char *desten; 364 struct rtentry *rt0; 365 { 366 register struct llinfo_arp *la = 0; 367 struct sockaddr_dl *sdl; 368 369 if (m->m_flags & M_BCAST) { /* broadcast */ 370 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 371 return (1); 372 } 373 if (m->m_flags & M_MCAST) { /* multicast */ 374 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 375 return(1); 376 } 377 if (rt) 378 la = (struct llinfo_arp *)rt->rt_llinfo; 379 if (la == 0) { 380 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 381 if (la) 382 rt = la->la_rt; 383 } 384 if (la == 0 || rt == 0) { 385 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 386 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 387 rt ? "rt" : ""); 388 m_freem(m); 389 return (0); 390 } 391 sdl = SDL(rt->rt_gateway); 392 /* 393 * Check the address family and length is valid, the address 394 * is resolved; otherwise, try to resolve. 395 */ 396 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 397 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 398 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 399 return 1; 400 } 401 /* 402 * There is an arptab entry, but no ethernet address 403 * response yet. Replace the held mbuf with this 404 * latest one. 405 */ 406 if (la->la_hold) 407 m_freem(la->la_hold); 408 la->la_hold = m; 409 if (rt->rt_expire) { 410 rt->rt_flags &= ~RTF_REJECT; 411 if (la->la_asked == 0 || rt->rt_expire != time_second) { 412 rt->rt_expire = time_second; 413 if (la->la_asked++ < arp_maxtries) 414 arprequest(ac, 415 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 416 &SIN(dst)->sin_addr, ac->ac_enaddr); 417 else { 418 rt->rt_flags |= RTF_REJECT; 419 rt->rt_expire += arpt_down; 420 la->la_asked = 0; 421 } 422 423 } 424 } 425 return (0); 426 } 427 428 /* 429 * Common length and type checks are done here, 430 * then the protocol-specific routine is called. 431 */ 432 static void 433 arpintr() 434 { 435 register struct mbuf *m; 436 register struct arphdr *ar; 437 int s; 438 439 while (arpintrq.ifq_head) { 440 s = splimp(); 441 IF_DEQUEUE(&arpintrq, m); 442 splx(s); 443 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 444 panic("arpintr"); 445 446 if (m->m_len < sizeof(struct arphdr) && 447 ((m = m_pullup(m, sizeof(struct arphdr))) == NULL)) { 448 log(LOG_ERR, "arp: runt packet -- m_pullup failed\n"); 449 continue; 450 } 451 ar = mtod(m, struct arphdr *); 452 453 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER 454 && ntohs(ar->ar_hrd) != ARPHRD_IEEE802) { 455 log(LOG_ERR, 456 "arp: unknown hardware address format (0x%2D)\n", 457 (unsigned char *)&ar->ar_hrd, ""); 458 m_freem(m); 459 continue; 460 } 461 462 if (m->m_pkthdr.len < sizeof(struct arphdr) + 2 * ar->ar_hln 463 + 2 * ar->ar_pln) { 464 log(LOG_ERR, "arp: runt packet\n"); 465 m_freem(m); 466 continue; 467 } 468 469 switch (ntohs(ar->ar_pro)) { 470 #ifdef INET 471 case ETHERTYPE_IP: 472 in_arpinput(m); 473 continue; 474 #endif 475 } 476 m_freem(m); 477 } 478 } 479 480 #ifdef INET 481 /* 482 * ARP for Internet protocols on 10 Mb/s Ethernet. 483 * Algorithm is that given in RFC 826. 484 * In addition, a sanity check is performed on the sender 485 * protocol address, to catch impersonators. 486 * We no longer handle negotiations for use of trailer protocol: 487 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 488 * along with IP replies if we wanted trailers sent to us, 489 * and also sent them in response to IP replies. 490 * This allowed either end to announce the desire to receive 491 * trailer packets. 492 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 493 * but formerly didn't normally send requests. 494 */ 495 static void 496 in_arpinput(m) 497 struct mbuf *m; 498 { 499 register struct ether_arp *ea; 500 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 501 struct ether_header *eh; 502 struct iso88025_header *th = (struct iso88025_header *)0; 503 register struct llinfo_arp *la = 0; 504 register struct rtentry *rt; 505 struct in_ifaddr *ia, *maybe_ia = 0; 506 struct sockaddr_dl *sdl; 507 struct sockaddr sa; 508 struct in_addr isaddr, itaddr, myaddr; 509 int op, rif_len; 510 511 ea = mtod(m, struct ether_arp *); 512 op = ntohs(ea->arp_op); 513 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 514 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 515 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 516 #ifdef BRIDGE 517 /* 518 * For a bridge, we want to check the address irrespective 519 * of the receive interface. (This will change slightly 520 * when we have clusters of interfaces). 521 */ 522 { 523 #else 524 if (ia->ia_ifp == &ac->ac_if) { 525 #endif 526 maybe_ia = ia; 527 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 528 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 529 break; 530 } 531 if (maybe_ia == 0) { 532 m_freem(m); 533 return; 534 } 535 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 536 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 537 sizeof (ea->arp_sha))) { 538 m_freem(m); /* it's from me, ignore it. */ 539 return; 540 } 541 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 542 sizeof (ea->arp_sha))) { 543 log(LOG_ERR, 544 "arp: ether address is broadcast for IP address %s!\n", 545 inet_ntoa(isaddr)); 546 m_freem(m); 547 return; 548 } 549 if (isaddr.s_addr == myaddr.s_addr) { 550 log(LOG_ERR, 551 "arp: %6D is using my IP address %s!\n", 552 ea->arp_sha, ":", inet_ntoa(isaddr)); 553 itaddr = myaddr; 554 goto reply; 555 } 556 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 557 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 558 #ifndef BRIDGE /* the following is not an error when doing bridging */ 559 if (rt->rt_ifp != &ac->ac_if) { 560 log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 561 inet_ntoa(isaddr), 562 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 563 ea->arp_sha, ":", 564 ac->ac_if.if_name, ac->ac_if.if_unit); 565 goto reply; 566 } 567 #endif 568 if (sdl->sdl_alen && 569 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 570 if (rt->rt_expire) 571 log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 572 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 573 ea->arp_sha, ":", 574 ac->ac_if.if_name, ac->ac_if.if_unit); 575 else { 576 log(LOG_ERR, 577 "arp: %6D attempts to modify permanent entry for %s on %s%d\n", 578 ea->arp_sha, ":", inet_ntoa(isaddr), 579 ac->ac_if.if_name, ac->ac_if.if_unit); 580 goto reply; 581 } 582 } 583 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 584 sdl->sdl_alen = sizeof(ea->arp_sha); 585 sdl->sdl_rcf = (u_short)0; 586 /* 587 * If we receive an arp from a token-ring station over 588 * a token-ring nic then try to save the source 589 * routing info. 590 */ 591 if (ac->ac_if.if_type == IFT_ISO88025) { 592 th = (struct iso88025_header *)m->m_pkthdr.header; 593 rif_len = TR_RCF_RIFLEN(th->rcf); 594 if ((th->iso88025_shost[0] & TR_RII) && 595 (rif_len > 2)) { 596 sdl->sdl_rcf = th->rcf; 597 sdl->sdl_rcf ^= htons(TR_RCF_DIR); 598 memcpy(sdl->sdl_route, th->rd, rif_len - 2); 599 sdl->sdl_rcf &= ~htons(TR_RCF_BCST_MASK); 600 /* 601 * Set up source routing information for 602 * reply packet (XXX) 603 */ 604 m->m_data -= rif_len; 605 m->m_len += rif_len; 606 m->m_pkthdr.len += rif_len; 607 } else { 608 th->iso88025_shost[0] &= ~TR_RII; 609 } 610 m->m_data -= 8; 611 m->m_len += 8; 612 m->m_pkthdr.len += 8; 613 th->rcf = sdl->sdl_rcf; 614 } else { 615 sdl->sdl_rcf = (u_short)0; 616 } 617 if (rt->rt_expire) 618 rt->rt_expire = time_second + arpt_keep; 619 rt->rt_flags &= ~RTF_REJECT; 620 la->la_asked = 0; 621 if (la->la_hold) { 622 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 623 rt_key(rt), rt); 624 la->la_hold = 0; 625 } 626 } 627 reply: 628 if (op != ARPOP_REQUEST) { 629 m_freem(m); 630 return; 631 } 632 if (itaddr.s_addr == myaddr.s_addr) { 633 /* I am the target */ 634 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 635 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 636 } else { 637 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 638 if (la == NULL) { 639 struct sockaddr_in sin; 640 641 if (!arp_proxyall) { 642 m_freem(m); 643 return; 644 } 645 646 bzero(&sin, sizeof sin); 647 sin.sin_family = AF_INET; 648 sin.sin_len = sizeof sin; 649 sin.sin_addr = itaddr; 650 651 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 652 if (!rt) { 653 m_freem(m); 654 return; 655 } 656 /* 657 * Don't send proxies for nodes on the same interface 658 * as this one came out of, or we'll get into a fight 659 * over who claims what Ether address. 660 */ 661 if (rt->rt_ifp == &ac->ac_if) { 662 rtfree(rt); 663 m_freem(m); 664 return; 665 } 666 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 667 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 668 rtfree(rt); 669 #ifdef DEBUG_PROXY 670 printf("arp: proxying for %s\n", 671 inet_ntoa(itaddr)); 672 #endif 673 } else { 674 rt = la->la_rt; 675 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 676 sdl = SDL(rt->rt_gateway); 677 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 678 } 679 } 680 681 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 682 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 683 ea->arp_op = htons(ARPOP_REPLY); 684 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 685 switch (ac->ac_if.if_type) { 686 case IFT_ISO88025: 687 /* Re-arrange the source/dest address */ 688 memcpy(th->iso88025_dhost, th->iso88025_shost, 689 sizeof(th->iso88025_dhost)); 690 memcpy(th->iso88025_shost, ac->ac_enaddr, 691 sizeof(th->iso88025_shost)); 692 /* Set the source routing bit if neccesary */ 693 if (th->iso88025_dhost[0] & TR_RII) { 694 th->iso88025_dhost[0] &= ~TR_RII; 695 if (TR_RCF_RIFLEN(th->rcf) > 2) 696 th->iso88025_shost[0] |= TR_RII; 697 } 698 /* Copy the addresses, ac and fc into sa_data */ 699 memcpy(sa.sa_data, th->iso88025_dhost, 700 sizeof(th->iso88025_dhost) * 2); 701 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 702 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 703 break; 704 case IFT_ETHER: 705 case IFT_FDDI: 706 /* 707 * May not be correct for types not explictly 708 * listed, but it is our best guess. 709 */ 710 default: 711 eh = (struct ether_header *)sa.sa_data; 712 (void)memcpy(eh->ether_dhost, ea->arp_tha, 713 sizeof(eh->ether_dhost)); 714 eh->ether_type = htons(ETHERTYPE_ARP); 715 break; 716 } 717 sa.sa_family = AF_UNSPEC; 718 sa.sa_len = sizeof(sa); 719 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 720 return; 721 } 722 #endif 723 724 /* 725 * Free an arp entry. 726 */ 727 static void 728 arptfree(la) 729 register struct llinfo_arp *la; 730 { 731 register struct rtentry *rt = la->la_rt; 732 register struct sockaddr_dl *sdl; 733 if (rt == 0) 734 panic("arptfree"); 735 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 736 sdl->sdl_family == AF_LINK) { 737 sdl->sdl_alen = 0; 738 la->la_asked = 0; 739 rt->rt_flags &= ~RTF_REJECT; 740 return; 741 } 742 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 743 0, (struct rtentry **)0); 744 } 745 /* 746 * Lookup or enter a new address in arptab. 747 */ 748 static struct llinfo_arp * 749 arplookup(addr, create, proxy) 750 u_long addr; 751 int create, proxy; 752 { 753 register struct rtentry *rt; 754 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 755 const char *why = 0; 756 757 sin.sin_addr.s_addr = addr; 758 sin.sin_other = proxy ? SIN_PROXY : 0; 759 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 760 if (rt == 0) 761 return (0); 762 rt->rt_refcnt--; 763 764 if (rt->rt_flags & RTF_GATEWAY) 765 why = "host is not on local network"; 766 else if ((rt->rt_flags & RTF_LLINFO) == 0) 767 why = "could not allocate llinfo"; 768 else if (rt->rt_gateway->sa_family != AF_LINK) 769 why = "gateway route is not ours"; 770 771 if (why && create) { 772 log(LOG_DEBUG, "arplookup %s failed: %s\n", 773 inet_ntoa(sin.sin_addr), why); 774 return 0; 775 } else if (why) { 776 return 0; 777 } 778 return ((struct llinfo_arp *)rt->rt_llinfo); 779 } 780 781 void 782 arp_ifinit(ac, ifa) 783 struct arpcom *ac; 784 struct ifaddr *ifa; 785 { 786 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 787 arprequest(ac, &IA_SIN(ifa)->sin_addr, 788 &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 789 ifa->ifa_rtrequest = arp_rtrequest; 790 ifa->ifa_flags |= RTF_CLONING; 791 } 792