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: src/sys/netinet/if_ether.c,v 1.34.2.4 1999/09/05 08:18:12 peter Exp $ 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 <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/sysctl.h> 46 #include <sys/queue.h> 47 #include <sys/systm.h> 48 #include <sys/mbuf.h> 49 #include <sys/malloc.h> 50 #include <sys/socket.h> 51 #include <sys/syslog.h> 52 53 #include <net/if.h> 54 #include <net/if_dl.h> 55 #include <net/route.h> 56 #include <net/netisr.h> 57 58 #include <netinet/in.h> 59 #include <netinet/in_var.h> 60 #include <netinet/if_ether.h> 61 62 #define SIN(s) ((struct sockaddr_in *)s) 63 #define SDL(s) ((struct sockaddr_dl *)s) 64 65 SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 66 67 /* timer values */ 68 static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 69 static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 70 static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 71 72 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 73 &arpt_prune, 0, ""); 74 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 75 &arpt_keep, 0, ""); 76 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 77 &arpt_down, 0, ""); 78 79 #define rt_expire rt_rmx.rmx_expire 80 81 struct llinfo_arp { 82 LIST_ENTRY(llinfo_arp) la_le; 83 struct rtentry *la_rt; 84 struct mbuf *la_hold; /* last packet until resolved/timeout */ 85 long la_asked; /* last time we QUERIED for this addr */ 86 #define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 87 }; 88 89 static LIST_HEAD(, llinfo_arp) llinfo_arp; 90 91 struct ifqueue arpintrq = {0, 0, 0, 50}; 92 static int arp_inuse, arp_allocated; 93 94 static int arp_maxtries = 5; 95 static int useloopback = 1; /* use loopback interface for local traffic */ 96 static int arp_proxyall = 0; 97 98 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 99 &arp_maxtries, 0, ""); 100 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 101 &useloopback, 0, ""); 102 SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 103 &arp_proxyall, 0, ""); 104 105 static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 106 static void arprequest __P((struct arpcom *, u_long *, u_long *, u_char *)); 107 static void arpintr __P((void)); 108 static void arptfree __P((struct llinfo_arp *)); 109 static void arptimer __P((void *)); 110 static struct llinfo_arp 111 *arplookup __P((u_long, int, int)); 112 static void in_arpinput __P((struct mbuf *)); 113 114 /* 115 * Timeout routine. Age arp_tab entries periodically. 116 */ 117 /* ARGSUSED */ 118 static void 119 arptimer(ignored_arg) 120 void *ignored_arg; 121 { 122 int s = splnet(); 123 register struct llinfo_arp *la = llinfo_arp.lh_first; 124 struct llinfo_arp *ola; 125 126 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 127 while ((ola = la) != 0) { 128 register struct rtentry *rt = la->la_rt; 129 la = la->la_le.le_next; 130 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 131 arptfree(ola); /* timer has expired, clear */ 132 } 133 splx(s); 134 } 135 136 /* 137 * Parallel to llc_rtrequest. 138 */ 139 static void 140 arp_rtrequest(req, rt, sa) 141 int req; 142 register struct rtentry *rt; 143 struct sockaddr *sa; 144 { 145 register struct sockaddr *gate = rt->rt_gateway; 146 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 147 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 148 static int arpinit_done; 149 150 if (!arpinit_done) { 151 arpinit_done = 1; 152 LIST_INIT(&llinfo_arp); 153 timeout(arptimer, (caddr_t)0, hz); 154 } 155 if (rt->rt_flags & RTF_GATEWAY) 156 return; 157 switch (req) { 158 159 case RTM_ADD: 160 /* 161 * XXX: If this is a manually added route to interface 162 * such as older version of routed or gated might provide, 163 * restore cloning bit. 164 */ 165 if ((rt->rt_flags & RTF_HOST) == 0 && 166 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 167 rt->rt_flags |= RTF_CLONING; 168 if (rt->rt_flags & RTF_CLONING) { 169 /* 170 * Case 1: This route should come from a route to iface. 171 */ 172 rt_setgate(rt, rt_key(rt), 173 (struct sockaddr *)&null_sdl); 174 gate = rt->rt_gateway; 175 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 176 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 177 rt->rt_expire = time.tv_sec; 178 break; 179 } 180 /* Announce a new entry if requested. */ 181 if (rt->rt_flags & RTF_ANNOUNCE) 182 arprequest((struct arpcom *)rt->rt_ifp, 183 &SIN(rt_key(rt))->sin_addr.s_addr, 184 &SIN(rt_key(rt))->sin_addr.s_addr, 185 (u_char *)LLADDR(SDL(gate))); 186 /*FALLTHROUGH*/ 187 case RTM_RESOLVE: 188 if (gate->sa_family != AF_LINK || 189 gate->sa_len < sizeof(null_sdl)) { 190 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 191 break; 192 } 193 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 194 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 195 if (la != 0) 196 break; /* This happens on a route change */ 197 /* 198 * Case 2: This route may come from cloning, or a manual route 199 * add with a LL address. 200 */ 201 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 202 rt->rt_llinfo = (caddr_t)la; 203 if (la == 0) { 204 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 205 break; 206 } 207 arp_inuse++, arp_allocated++; 208 Bzero(la, sizeof(*la)); 209 la->la_rt = rt; 210 rt->rt_flags |= RTF_LLINFO; 211 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 212 213 /* 214 * This keeps the multicast addresses from showing up 215 * in `arp -a' listings as unresolved. It's not actually 216 * functional. Then the same for broadcast. 217 */ 218 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 219 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 220 LLADDR(SDL(gate))); 221 SDL(gate)->sdl_alen = 6; 222 rt->rt_expire = 0; 223 } 224 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 225 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 226 SDL(gate)->sdl_alen = 6; 227 rt->rt_expire = 0; 228 } 229 230 if (SIN(rt_key(rt))->sin_addr.s_addr == 231 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 232 /* 233 * This test used to be 234 * if (loif.if_flags & IFF_UP) 235 * It allowed local traffic to be forced 236 * through the hardware by configuring the loopback down. 237 * However, it causes problems during network configuration 238 * for boards that can't receive packets they send. 239 * It is now necessary to clear "useloopback" and remove 240 * the route to force traffic out to the hardware. 241 */ 242 rt->rt_expire = 0; 243 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 244 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 245 if (useloopback) 246 rt->rt_ifp = loif; 247 248 } 249 break; 250 251 case RTM_DELETE: 252 if (la == 0) 253 break; 254 arp_inuse--; 255 LIST_REMOVE(la, la_le); 256 rt->rt_llinfo = 0; 257 rt->rt_flags &= ~RTF_LLINFO; 258 if (la->la_hold) 259 m_freem(la->la_hold); 260 Free((caddr_t)la); 261 } 262 } 263 264 /* 265 * Broadcast an ARP request. Caller specifies: 266 * - arp header source ip address 267 * - arp header target ip address 268 * - arp header source ethernet address 269 */ 270 static void 271 arprequest(ac, sip, tip, enaddr) 272 register struct arpcom *ac; 273 register u_long *sip, *tip; 274 register u_char *enaddr; 275 { 276 register struct mbuf *m; 277 register struct ether_header *eh; 278 register struct ether_arp *ea; 279 struct sockaddr sa; 280 281 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 282 return; 283 m->m_len = sizeof(*ea); 284 m->m_pkthdr.len = sizeof(*ea); 285 MH_ALIGN(m, sizeof(*ea)); 286 ea = mtod(m, struct ether_arp *); 287 eh = (struct ether_header *)sa.sa_data; 288 bzero((caddr_t)ea, sizeof (*ea)); 289 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 290 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 291 ea->arp_hrd = htons(ARPHRD_ETHER); 292 ea->arp_pro = htons(ETHERTYPE_IP); 293 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 294 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 295 ea->arp_op = htons(ARPOP_REQUEST); 296 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 297 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 298 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 299 sa.sa_family = AF_UNSPEC; 300 sa.sa_len = sizeof(sa); 301 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 302 } 303 304 /* 305 * Resolve an IP address into an ethernet address. If success, 306 * desten is filled in. If there is no entry in arptab, 307 * set one up and broadcast a request for the IP address. 308 * Hold onto this mbuf and resend it once the address 309 * is finally resolved. A return value of 1 indicates 310 * that desten has been filled in and the packet should be sent 311 * normally; a 0 return indicates that the packet has been 312 * taken over here, either now or for later transmission. 313 */ 314 int 315 arpresolve(ac, rt, m, dst, desten, rt0) 316 register struct arpcom *ac; 317 register struct rtentry *rt; 318 struct mbuf *m; 319 register struct sockaddr *dst; 320 register u_char *desten; 321 struct rtentry *rt0; 322 { 323 register struct llinfo_arp *la; 324 struct sockaddr_dl *sdl; 325 326 if (m->m_flags & M_BCAST) { /* broadcast */ 327 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 328 return (1); 329 } 330 if (m->m_flags & M_MCAST) { /* multicast */ 331 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 332 return(1); 333 } 334 if (rt) 335 la = (struct llinfo_arp *)rt->rt_llinfo; 336 else { 337 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 338 if (la) 339 rt = la->la_rt; 340 } 341 if (la == 0 || rt == 0) { 342 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s\n", 343 inet_ntoa(SIN(dst)->sin_addr)); 344 m_freem(m); 345 return (0); 346 } 347 sdl = SDL(rt->rt_gateway); 348 /* 349 * Check the address family and length is valid, the address 350 * is resolved; otherwise, try to resolve. 351 */ 352 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 353 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 354 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 355 return 1; 356 } 357 /* 358 * There is an arptab entry, but no ethernet address 359 * response yet. Replace the held mbuf with this 360 * latest one. 361 */ 362 if (la->la_hold) 363 m_freem(la->la_hold); 364 la->la_hold = m; 365 if (rt->rt_expire) { 366 rt->rt_flags &= ~RTF_REJECT; 367 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 368 rt->rt_expire = time.tv_sec; 369 if (la->la_asked++ < arp_maxtries) 370 arprequest(ac, 371 &(SIN(rt->rt_ifa->ifa_addr)->sin_addr.s_addr), 372 &(SIN(dst)->sin_addr.s_addr), 373 ac->ac_enaddr); 374 else { 375 rt->rt_flags |= RTF_REJECT; 376 rt->rt_expire += arpt_down; 377 la->la_asked = 0; 378 } 379 380 } 381 } 382 return (0); 383 } 384 385 /* 386 * Common length and type checks are done here, 387 * then the protocol-specific routine is called. 388 */ 389 static void 390 arpintr(void) 391 { 392 register struct mbuf *m; 393 register struct arphdr *ar; 394 int s; 395 396 while (arpintrq.ifq_head) { 397 s = splimp(); 398 IF_DEQUEUE(&arpintrq, m); 399 splx(s); 400 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 401 panic("arpintr"); 402 if (m->m_len >= sizeof(struct arphdr) && 403 (ar = mtod(m, struct arphdr *)) && 404 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 405 m->m_len >= 406 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 407 408 switch (ntohs(ar->ar_pro)) { 409 410 case ETHERTYPE_IP: 411 in_arpinput(m); 412 continue; 413 } 414 m_freem(m); 415 } 416 } 417 418 NETISR_SET(NETISR_ARP, arpintr); 419 420 /* 421 * ARP for Internet protocols on 10 Mb/s Ethernet. 422 * Algorithm is that given in RFC 826. 423 * In addition, a sanity check is performed on the sender 424 * protocol address, to catch impersonators. 425 * We no longer handle negotiations for use of trailer protocol: 426 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 427 * along with IP replies if we wanted trailers sent to us, 428 * and also sent them in response to IP replies. 429 * This allowed either end to announce the desire to receive 430 * trailer packets. 431 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 432 * but formerly didn't normally send requests. 433 */ 434 static void 435 in_arpinput(m) 436 struct mbuf *m; 437 { 438 register struct ether_arp *ea; 439 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 440 struct ether_header *eh; 441 register struct llinfo_arp *la = 0; 442 register struct rtentry *rt; 443 struct in_ifaddr *ia, *maybe_ia = 0; 444 struct sockaddr_dl *sdl; 445 struct sockaddr sa; 446 struct in_addr isaddr, itaddr, myaddr; 447 int op; 448 449 ea = mtod(m, struct ether_arp *); 450 op = ntohs(ea->arp_op); 451 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 452 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 453 for (ia = in_ifaddr; ia; ia = ia->ia_next) 454 #ifdef BRIDGE 455 /* 456 * For a bridge, we want to check the address irrespective 457 * of the receive interface. (This will change slightly 458 * when we have clusters of interfaces). 459 */ 460 { 461 #else 462 if (ia->ia_ifp == &ac->ac_if) { 463 #endif 464 maybe_ia = ia; 465 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 466 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 467 break; 468 } 469 if (maybe_ia == 0) { 470 m_freem(m); 471 return; 472 } 473 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 474 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 475 sizeof (ea->arp_sha))) { 476 m_freem(m); /* it's from me, ignore it. */ 477 return; 478 } 479 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 480 sizeof (ea->arp_sha))) { 481 log(LOG_ERR, 482 "arp: ether address is broadcast for IP address %s!\n", 483 inet_ntoa(isaddr)); 484 m_freem(m); 485 return; 486 } 487 if (isaddr.s_addr == myaddr.s_addr) { 488 log(LOG_ERR, 489 "arp: %6D is using my IP address %s!\n", 490 ea->arp_sha, ":", inet_ntoa(isaddr)); 491 itaddr = myaddr; 492 goto reply; 493 } 494 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 495 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 496 if (sdl->sdl_alen && 497 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 498 log(LOG_INFO, "arp: %s moved from %6D to %6D\n", 499 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 500 ea->arp_sha, ":"); 501 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 502 sdl->sdl_alen = sizeof(ea->arp_sha); 503 if (rt->rt_expire) 504 rt->rt_expire = time.tv_sec + arpt_keep; 505 rt->rt_flags &= ~RTF_REJECT; 506 la->la_asked = 0; 507 if (la->la_hold) { 508 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 509 rt_key(rt), rt); 510 la->la_hold = 0; 511 } 512 } 513 reply: 514 if (op != ARPOP_REQUEST) { 515 m_freem(m); 516 return; 517 } 518 if (itaddr.s_addr == myaddr.s_addr) { 519 /* I am the target */ 520 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 521 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 522 } else { 523 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 524 if (la == NULL) { 525 struct sockaddr_in sin; 526 527 if (!arp_proxyall) { 528 m_freem(m); 529 return; 530 } 531 532 bzero(&sin, sizeof sin); 533 sin.sin_family = AF_INET; 534 sin.sin_len = sizeof sin; 535 sin.sin_addr = itaddr; 536 537 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 538 if (!rt) { 539 m_freem(m); 540 return; 541 } 542 /* 543 * Don't send proxies for nodes on the same interface 544 * as this one came out of, or we'll get into a fight 545 * over who claims what Ether address. 546 */ 547 if (rt->rt_ifp == &ac->ac_if) { 548 rtfree(rt); 549 m_freem(m); 550 return; 551 } 552 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 553 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 554 rtfree(rt); 555 #ifdef DEBUG_PROXY 556 printf("arp: proxying for %s\n", 557 inet_ntoa(itaddr)); 558 #endif 559 } else { 560 rt = la->la_rt; 561 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 562 sdl = SDL(rt->rt_gateway); 563 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 564 } 565 } 566 567 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 568 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 569 ea->arp_op = htons(ARPOP_REPLY); 570 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 571 eh = (struct ether_header *)sa.sa_data; 572 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 573 eh->ether_type = htons(ETHERTYPE_ARP); 574 sa.sa_family = AF_UNSPEC; 575 sa.sa_len = sizeof(sa); 576 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 577 return; 578 } 579 580 /* 581 * Free an arp entry. 582 */ 583 static void 584 arptfree(la) 585 register struct llinfo_arp *la; 586 { 587 register struct rtentry *rt = la->la_rt; 588 register struct sockaddr_dl *sdl; 589 if (rt == 0) 590 panic("arptfree"); 591 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 592 sdl->sdl_family == AF_LINK) { 593 sdl->sdl_alen = 0; 594 la->la_asked = 0; 595 rt->rt_flags &= ~RTF_REJECT; 596 return; 597 } 598 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 599 0, (struct rtentry **)0); 600 } 601 /* 602 * Lookup or enter a new address in arptab. 603 */ 604 static struct llinfo_arp * 605 arplookup(addr, create, proxy) 606 u_long addr; 607 int create, proxy; 608 { 609 register struct rtentry *rt; 610 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 611 const char *why = 0; 612 613 sin.sin_addr.s_addr = addr; 614 sin.sin_other = proxy ? SIN_PROXY : 0; 615 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 616 if (rt == 0) 617 return (0); 618 rt->rt_refcnt--; 619 620 if (rt->rt_flags & RTF_GATEWAY) 621 why = "host is not on local network"; 622 else if ((rt->rt_flags & RTF_LLINFO) == 0) 623 why = "could not allocate llinfo"; 624 else if (rt->rt_gateway->sa_family != AF_LINK) 625 why = "gateway route is not ours"; 626 627 if (why && create) { 628 log(LOG_DEBUG, "arplookup %s failed: %s\n", 629 inet_ntoa(sin.sin_addr), why); 630 return 0; 631 } else if (why) { 632 return 0; 633 } 634 return ((struct llinfo_arp *)rt->rt_llinfo); 635 } 636 637 void 638 arp_ifinit(ac, ifa) 639 struct arpcom *ac; 640 struct ifaddr *ifa; 641 { 642 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 643 arprequest(ac, &(IA_SIN(ifa)->sin_addr.s_addr), 644 &(IA_SIN(ifa)->sin_addr.s_addr), ac->ac_enaddr); 645 ifa->ifa_rtrequest = arp_rtrequest; 646 ifa->ifa_flags |= RTF_CLONING; 647 }
Cache object: 589ca095654ec701c7f4b0c3180b4ab9
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