Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/if_ether.c
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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/sysctl.h> 49 #include <sys/systm.h> 50 #include <sys/mbuf.h> 51 #include <sys/malloc.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 55 #include <net/if.h> 56 #include <net/if_dl.h> 57 #include <net/if_types.h> 58 #include <net/route.h> 59 #include <net/netisr.h> 60 61 #include <netinet/in.h> 62 #include <netinet/in_var.h> 63 #include <netinet/if_ether.h> 64 65 #include <net/iso88025.h> 66 67 #define SIN(s) ((struct sockaddr_in *)s) 68 #define SDL(s) ((struct sockaddr_dl *)s) 69 70 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 71 72 /* timer values */ 73 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 74 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 75 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 76 77 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 78 &arpt_prune, 0, ""); 79 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 80 &arpt_keep, 0, ""); 81 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 82 &arpt_down, 0, ""); 83 84 #define rt_expire rt_rmx.rmx_expire 85 86 struct llinfo_arp { 87 LIST_ENTRY(llinfo_arp) la_le; 88 struct rtentry *la_rt; 89 struct mbuf *la_hold; /* last packet until resolved/timeout */ 90 long la_asked; /* last time we QUERIED for this addr */ 91 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 92 }; 93 94 static LIST_HEAD(, llinfo_arp) llinfo_arp; 95 96 struct ifqueue arpintrq = {0, 0, 0, 50}; 97 static int arp_inuse, arp_allocated; 98 99 static int arp_maxtries = 5; 100 static int useloopback = 1; /* use loopback interface for local traffic */ 101 static int arp_proxyall = 0; 102 103 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 104 &arp_maxtries, 0, ""); 105 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 106 &useloopback, 0, ""); 107 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 108 &arp_proxyall, 0, ""); 109 110 static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 111 static void arprequest __P((struct arpcom *, 112 struct in_addr *, struct in_addr *, u_char *)); 113 static void arpintr __P((void)); 114 static void arptfree __P((struct llinfo_arp *)); 115 static void arptimer __P((void *)); 116 static struct llinfo_arp 117 *arplookup __P((u_long, int, int)); 118 #ifdef INET 119 static void in_arpinput __P((struct mbuf *)); 120 #endif 121 122 /* 123 * Timeout routine. Age arp_tab entries periodically. 124 */ 125 /* ARGSUSED */ 126 static void 127 arptimer(ignored_arg) 128 void *ignored_arg; 129 { 130 int s = splnet(); 131 register struct llinfo_arp *la = llinfo_arp.lh_first; 132 struct llinfo_arp *ola; 133 134 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 135 while ((ola = la) != 0) { 136 register struct rtentry *rt = la->la_rt; 137 la = la->la_le.le_next; 138 if (rt->rt_expire && rt->rt_expire <= time_second) 139 arptfree(ola); /* timer has expired, clear */ 140 } 141 splx(s); 142 } 143 144 /* 145 * Parallel to llc_rtrequest. 146 */ 147 static void 148 arp_rtrequest(req, rt, sa) 149 int req; 150 register struct rtentry *rt; 151 struct sockaddr *sa; 152 { 153 register struct sockaddr *gate = rt->rt_gateway; 154 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 155 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 156 static int arpinit_done; 157 158 if (!arpinit_done) { 159 arpinit_done = 1; 160 LIST_INIT(&llinfo_arp); 161 timeout(arptimer, (caddr_t)0, hz); 162 } 163 if (rt->rt_flags & RTF_GATEWAY) 164 return; 165 switch (req) { 166 167 case RTM_ADD: 168 /* 169 * XXX: If this is a manually added route to interface 170 * such as older version of routed or gated might provide, 171 * restore cloning bit. 172 */ 173 if ((rt->rt_flags & RTF_HOST) == 0 && 174 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 175 rt->rt_flags |= RTF_CLONING; 176 if (rt->rt_flags & RTF_CLONING) { 177 /* 178 * Case 1: This route should come from a route to iface. 179 */ 180 rt_setgate(rt, rt_key(rt), 181 (struct sockaddr *)&null_sdl); 182 gate = rt->rt_gateway; 183 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 184 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 185 rt->rt_expire = time_second; 186 break; 187 } 188 /* Announce a new entry if requested. */ 189 if (rt->rt_flags & RTF_ANNOUNCE) 190 arprequest((struct arpcom *)rt->rt_ifp, 191 &SIN(rt_key(rt))->sin_addr, 192 &SIN(rt_key(rt))->sin_addr, 193 (u_char *)LLADDR(SDL(gate))); 194 /*FALLTHROUGH*/ 195 case RTM_RESOLVE: 196 if (gate->sa_family != AF_LINK || 197 gate->sa_len < sizeof(null_sdl)) { 198 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 199 break; 200 } 201 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 202 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 203 if (la != 0) 204 break; /* This happens on a route change */ 205 /* 206 * Case 2: This route may come from cloning, or a manual route 207 * add with a LL address. 208 */ 209 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 210 rt->rt_llinfo = (caddr_t)la; 211 if (la == 0) { 212 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 213 break; 214 } 215 arp_inuse++, arp_allocated++; 216 Bzero(la, sizeof(*la)); 217 la->la_rt = rt; 218 rt->rt_flags |= RTF_LLINFO; 219 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 220 221 #ifdef INET 222 /* 223 * This keeps the multicast addresses from showing up 224 * in `arp -a' listings as unresolved. It's not actually 225 * functional. Then the same for broadcast. 226 */ 227 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 228 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 229 LLADDR(SDL(gate))); 230 SDL(gate)->sdl_alen = 6; 231 rt->rt_expire = 0; 232 } 233 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 234 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 235 SDL(gate)->sdl_alen = 6; 236 rt->rt_expire = 0; 237 } 238 #endif 239 240 if (SIN(rt_key(rt))->sin_addr.s_addr == 241 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 242 /* 243 * This test used to be 244 * if (loif.if_flags & IFF_UP) 245 * It allowed local traffic to be forced 246 * through the hardware by configuring the loopback down. 247 * However, it causes problems during network configuration 248 * for boards that can't receive packets they send. 249 * It is now necessary to clear "useloopback" and remove 250 * the route to force traffic out to the hardware. 251 */ 252 rt->rt_expire = 0; 253 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 254 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 255 if (useloopback) 256 rt->rt_ifp = loif; 257 258 } 259 break; 260 261 case RTM_DELETE: 262 if (la == 0) 263 break; 264 arp_inuse--; 265 LIST_REMOVE(la, la_le); 266 rt->rt_llinfo = 0; 267 rt->rt_flags &= ~RTF_LLINFO; 268 if (la->la_hold) 269 m_freem(la->la_hold); 270 Free((caddr_t)la); 271 } 272 } 273 274 /* 275 * Broadcast an ARP request. Caller specifies: 276 * - arp header source ip address 277 * - arp header target ip address 278 * - arp header source ethernet address 279 */ 280 static void 281 arprequest(ac, sip, tip, enaddr) 282 register struct arpcom *ac; 283 register struct in_addr *sip, *tip; 284 register u_char *enaddr; 285 { 286 register struct mbuf *m; 287 register struct ether_header *eh; 288 register struct ether_arp *ea; 289 struct sockaddr sa; 290 291 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 292 return; 293 m->m_pkthdr.rcvif = (struct ifnet *)0; 294 switch (ac->ac_if.if_type) { 295 case IFT_ISO88025: 296 m->m_len = sizeof(*ea) + 10; 297 m->m_pkthdr.len = sizeof(*ea) + 10; 298 MH_ALIGN(m, sizeof(*ea) + 10); 299 (void)memcpy(mtod(m, caddr_t), 300 "\x82\x40\xaa\xaa\x03\x00\x00\x00\x08\x06", 10); 301 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 302 (void)memcpy(sa.sa_data + 6, enaddr, 6); 303 sa.sa_data[6] |= 0x80; 304 sa.sa_data[12] = 0x10; 305 sa.sa_data[13] = 0x40; 306 ea = (struct ether_arp *)(mtod(m, char *) + 10); 307 bzero((caddr_t)ea, sizeof (*ea)); 308 ea->arp_hrd = htons(ARPHRD_IEEE802); 309 break; 310 case IFT_FDDI: 311 case IFT_ETHER: 312 /* 313 * This may not be correct for types not explicitly 314 * listed, but this is our best guess 315 */ 316 default: 317 m->m_len = sizeof(*ea); 318 m->m_pkthdr.len = sizeof(*ea); 319 MH_ALIGN(m, sizeof(*ea)); 320 ea = mtod(m, struct ether_arp *); 321 eh = (struct ether_header *)sa.sa_data; 322 bzero((caddr_t)ea, sizeof (*ea)); 323 /* if_output will not swap */ 324 eh->ether_type = htons(ETHERTYPE_ARP); 325 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, 326 sizeof(eh->ether_dhost)); 327 ea->arp_hrd = htons(ARPHRD_ETHER); 328 break; 329 } 330 ea->arp_pro = htons(ETHERTYPE_IP); 331 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 332 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 333 ea->arp_op = htons(ARPOP_REQUEST); 334 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 335 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 336 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 337 sa.sa_family = AF_UNSPEC; 338 sa.sa_len = sizeof(sa); 339 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 340 } 341 342 /* 343 * Resolve an IP address into an ethernet address. If success, 344 * desten is filled in. If there is no entry in arptab, 345 * set one up and broadcast a request for the IP address. 346 * Hold onto this mbuf and resend it once the address 347 * is finally resolved. A return value of 1 indicates 348 * that desten has been filled in and the packet should be sent 349 * normally; a 0 return indicates that the packet has been 350 * taken over here, either now or for later transmission. 351 */ 352 int 353 arpresolve(ac, rt, m, dst, desten, rt0) 354 register struct arpcom *ac; 355 register struct rtentry *rt; 356 struct mbuf *m; 357 register struct sockaddr *dst; 358 register u_char *desten; 359 struct rtentry *rt0; 360 { 361 register struct llinfo_arp *la = 0; 362 struct sockaddr_dl *sdl; 363 364 if (m->m_flags & M_BCAST) { /* broadcast */ 365 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 366 return (1); 367 } 368 if (m->m_flags & M_MCAST) { /* multicast */ 369 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 370 return(1); 371 } 372 if (rt) 373 la = (struct llinfo_arp *)rt->rt_llinfo; 374 if (la == 0) { 375 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 376 if (la) 377 rt = la->la_rt; 378 } 379 if (la == 0 || rt == 0) { 380 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 381 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 382 rt ? "rt" : ""); 383 m_freem(m); 384 return (0); 385 } 386 sdl = SDL(rt->rt_gateway); 387 /* 388 * Check the address family and length is valid, the address 389 * is resolved; otherwise, try to resolve. 390 */ 391 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 392 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 393 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 394 return 1; 395 } 396 /* 397 * There is an arptab entry, but no ethernet address 398 * response yet. Replace the held mbuf with this 399 * latest one. 400 */ 401 if (la->la_hold) 402 m_freem(la->la_hold); 403 la->la_hold = m; 404 if (rt->rt_expire) { 405 rt->rt_flags &= ~RTF_REJECT; 406 if (la->la_asked == 0 || rt->rt_expire != time_second) { 407 rt->rt_expire = time_second; 408 if (la->la_asked++ < arp_maxtries) 409 arprequest(ac, 410 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 411 &SIN(dst)->sin_addr, ac->ac_enaddr); 412 else { 413 rt->rt_flags |= RTF_REJECT; 414 rt->rt_expire += arpt_down; 415 la->la_asked = 0; 416 } 417 418 } 419 } 420 return (0); 421 } 422 423 /* 424 * Common length and type checks are done here, 425 * then the protocol-specific routine is called. 426 */ 427 static void 428 arpintr() 429 { 430 register struct mbuf *m; 431 register struct arphdr *ar; 432 int s; 433 434 while (arpintrq.ifq_head) { 435 s = splimp(); 436 IF_DEQUEUE(&arpintrq, m); 437 splx(s); 438 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 439 panic("arpintr"); 440 if (m->m_len >= sizeof(struct arphdr) && 441 (ar = mtod(m, struct arphdr *)) && 442 (ntohs(ar->ar_hrd) == ARPHRD_ETHER || 443 ntohs(ar->ar_hrd) == ARPHRD_IEEE802) && 444 m->m_len >= 445 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 446 447 switch (ntohs(ar->ar_pro)) { 448 449 #ifdef INET 450 case ETHERTYPE_IP: 451 in_arpinput(m); 452 continue; 453 #endif 454 } 455 m_freem(m); 456 } 457 } 458 459 NETISR_SET(NETISR_ARP, arpintr); 460 461 462 #ifdef INET 463 /* 464 * ARP for Internet protocols on 10 Mb/s Ethernet. 465 * Algorithm is that given in RFC 826. 466 * In addition, a sanity check is performed on the sender 467 * protocol address, to catch impersonators. 468 * We no longer handle negotiations for use of trailer protocol: 469 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 470 * along with IP replies if we wanted trailers sent to us, 471 * and also sent them in response to IP replies. 472 * This allowed either end to announce the desire to receive 473 * trailer packets. 474 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 475 * but formerly didn't normally send requests. 476 */ 477 static void 478 in_arpinput(m) 479 struct mbuf *m; 480 { 481 register struct ether_arp *ea; 482 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 483 struct ether_header *eh; 484 struct iso88025_header *th = (struct iso88025_header *)0; 485 register struct llinfo_arp *la = 0; 486 register struct rtentry *rt; 487 struct in_ifaddr *ia, *maybe_ia = 0; 488 struct sockaddr_dl *sdl; 489 struct sockaddr sa; 490 struct in_addr isaddr, itaddr, myaddr; 491 int op; 492 493 ea = mtod(m, struct ether_arp *); 494 op = ntohs(ea->arp_op); 495 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 496 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 497 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 498 #ifdef BRIDGE 499 /* 500 * For a bridge, we want to check the address irrespective 501 * of the receive interface. (This will change slightly 502 * when we have clusters of interfaces). 503 */ 504 { 505 #else 506 if (ia->ia_ifp == &ac->ac_if) { 507 #endif 508 maybe_ia = ia; 509 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 510 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 511 break; 512 } 513 if (maybe_ia == 0) { 514 m_freem(m); 515 return; 516 } 517 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 518 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 519 sizeof (ea->arp_sha))) { 520 m_freem(m); /* it's from me, ignore it. */ 521 return; 522 } 523 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 524 sizeof (ea->arp_sha))) { 525 log(LOG_ERR, 526 "arp: ether address is broadcast for IP address %s!\n", 527 inet_ntoa(isaddr)); 528 m_freem(m); 529 return; 530 } 531 if (isaddr.s_addr == myaddr.s_addr) { 532 log(LOG_ERR, 533 "arp: %6D is using my IP address %s!\n", 534 ea->arp_sha, ":", inet_ntoa(isaddr)); 535 itaddr = myaddr; 536 goto reply; 537 } 538 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 539 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 540 #ifndef BRIDGE /* the following is not an error when doing bridging */ 541 if (rt->rt_ifp != &ac->ac_if) { 542 log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 543 inet_ntoa(isaddr), 544 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 545 ea->arp_sha, ":", 546 ac->ac_if.if_name, ac->ac_if.if_unit); 547 goto reply; 548 } 549 #endif 550 if (sdl->sdl_alen && 551 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 552 if (rt->rt_expire) 553 log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 554 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 555 ea->arp_sha, ":", 556 ac->ac_if.if_name, ac->ac_if.if_unit); 557 else { 558 log(LOG_ERR, 559 "arp: %6D attempts to modify permanent entry for %s on %s%d\n", 560 ea->arp_sha, ":", inet_ntoa(isaddr), 561 ac->ac_if.if_name, ac->ac_if.if_unit); 562 goto reply; 563 } 564 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 565 sdl->sdl_alen = sizeof(ea->arp_sha); 566 sdl->sdl_rcf = NULL; 567 /* 568 * If we receive an arp from a token-ring station over 569 * a token-ring nic then try to save the source 570 * routing info. 571 */ 572 if (ac->ac_if.if_type == IFT_ISO88025) { 573 th = (struct iso88025_header *)m->m_pkthdr.header; 574 if ((th->iso88025_shost[0] & 0x80) && 575 ((th->rcf & 0x001f) > 2)) { 576 sdl->sdl_rcf = (th->rcf & 0x8000) ? 577 (th->rcf & 0x7fff) : 578 (th->rcf | 0x8000); 579 memcpy(sdl->sdl_route, th->rseg, 580 (th->rcf & 0x001f) - 2); 581 sdl->sdl_rcf = sdl->sdl_rcf & 0xff1f; 582 /* 583 * Set up source routing information for 584 * reply packet (XXX) 585 */ 586 m->m_data -= (th->rcf & 0x001f); 587 m->m_len += (th->rcf & 0x001f); 588 m->m_pkthdr.len += (th->rcf & 0x001f); 589 } else { 590 th->iso88025_shost[0] &= 0x7f; 591 } 592 m->m_data -= 8; 593 m->m_len += 8; 594 m->m_pkthdr.len += 8; 595 th->rcf = sdl->sdl_rcf; 596 } else { 597 sdl->sdl_rcf = NULL; 598 } 599 if (rt->rt_expire) 600 rt->rt_expire = time_second + arpt_keep; 601 rt->rt_flags &= ~RTF_REJECT; 602 la->la_asked = 0; 603 if (la->la_hold) { 604 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 605 rt_key(rt), rt); 606 la->la_hold = 0; 607 } 608 } 609 reply: 610 if (op != ARPOP_REQUEST) { 611 m_freem(m); 612 return; 613 } 614 if (itaddr.s_addr == myaddr.s_addr) { 615 /* I am the target */ 616 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 617 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 618 } else { 619 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 620 if (la == NULL) { 621 struct sockaddr_in sin; 622 623 if (!arp_proxyall) { 624 m_freem(m); 625 return; 626 } 627 628 bzero(&sin, sizeof sin); 629 sin.sin_family = AF_INET; 630 sin.sin_len = sizeof sin; 631 sin.sin_addr = itaddr; 632 633 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 634 if (!rt) { 635 m_freem(m); 636 return; 637 } 638 /* 639 * Don't send proxies for nodes on the same interface 640 * as this one came out of, or we'll get into a fight 641 * over who claims what Ether address. 642 */ 643 if (rt->rt_ifp == &ac->ac_if) { 644 rtfree(rt); 645 m_freem(m); 646 return; 647 } 648 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 649 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 650 rtfree(rt); 651 #ifdef DEBUG_PROXY 652 printf("arp: proxying for %s\n", 653 inet_ntoa(itaddr)); 654 #endif 655 } else { 656 rt = la->la_rt; 657 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 658 sdl = SDL(rt->rt_gateway); 659 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 660 } 661 } 662 663 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 664 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 665 ea->arp_op = htons(ARPOP_REPLY); 666 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 667 switch (ac->ac_if.if_type) { 668 case IFT_ISO88025: 669 /* Re-arrange the source/dest address */ 670 memcpy(th->iso88025_dhost, th->iso88025_shost, 671 sizeof(th->iso88025_dhost)); 672 memcpy(th->iso88025_shost, ac->ac_enaddr, 673 sizeof(th->iso88025_shost)); 674 /* Set the source routing bit if neccesary */ 675 if (th->iso88025_dhost[0] & 0x80) { 676 th->iso88025_dhost[0] &= 0x7f; 677 if ((th->rcf & 0x001f) - 2) 678 th->iso88025_shost[0] |= 0x80; 679 } 680 /* Copy the addresses, ac and fc into sa_data */ 681 memcpy(sa.sa_data, th->iso88025_dhost, 682 sizeof(th->iso88025_dhost) * 2); 683 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = 0x10; 684 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = 0x40; 685 break; 686 case IFT_ETHER: 687 case IFT_FDDI: 688 /* 689 * May not be correct for types not explictly 690 * listed, but it is our best guess. 691 */ 692 default: 693 eh = (struct ether_header *)sa.sa_data; 694 (void)memcpy(eh->ether_dhost, ea->arp_tha, 695 sizeof(eh->ether_dhost)); 696 eh->ether_type = htons(ETHERTYPE_ARP); 697 break; 698 } 699 sa.sa_family = AF_UNSPEC; 700 sa.sa_len = sizeof(sa); 701 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 702 return; 703 } 704 #endif 705 706 /* 707 * Free an arp entry. 708 */ 709 static void 710 arptfree(la) 711 register struct llinfo_arp *la; 712 { 713 register struct rtentry *rt = la->la_rt; 714 register struct sockaddr_dl *sdl; 715 if (rt == 0) 716 panic("arptfree"); 717 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 718 sdl->sdl_family == AF_LINK) { 719 sdl->sdl_alen = 0; 720 la->la_asked = 0; 721 rt->rt_flags &= ~RTF_REJECT; 722 return; 723 } 724 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 725 0, (struct rtentry **)0); 726 } 727 /* 728 * Lookup or enter a new address in arptab. 729 */ 730 static struct llinfo_arp * 731 arplookup(addr, create, proxy) 732 u_long addr; 733 int create, proxy; 734 { 735 register struct rtentry *rt; 736 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 737 const char *why = 0; 738 739 sin.sin_addr.s_addr = addr; 740 sin.sin_other = proxy ? SIN_PROXY : 0; 741 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 742 if (rt == 0) 743 return (0); 744 rt->rt_refcnt--; 745 746 if (rt->rt_flags & RTF_GATEWAY) 747 why = "host is not on local network"; 748 else if ((rt->rt_flags & RTF_LLINFO) == 0) 749 why = "could not allocate llinfo"; 750 else if (rt->rt_gateway->sa_family != AF_LINK) 751 why = "gateway route is not ours"; 752 753 if (why && create) { 754 log(LOG_DEBUG, "arplookup %s failed: %s\n", 755 inet_ntoa(sin.sin_addr), why); 756 return 0; 757 } else if (why) { 758 return 0; 759 } 760 return ((struct llinfo_arp *)rt->rt_llinfo); 761 } 762 763 void 764 arp_ifinit(ac, ifa) 765 struct arpcom *ac; 766 struct ifaddr *ifa; 767 { 768 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 769 arprequest(ac, &IA_SIN(ifa)->sin_addr, 770 &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 771 ifa->ifa_rtrequest = arp_rtrequest; 772 ifa->ifa_flags |= RTF_CLONING; 773 }
Cache object: e4bb716117b1d79597e81d6b52cd457f
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