if_ether.c revision 42775
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 * $Id: if_ether.c,v 1.50 1999/01/10 17:40:10 luigi 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 "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/route.h> 58#include <net/netisr.h> 59 60#include <netinet/in.h> 61#include <netinet/in_var.h> 62#include <netinet/if_ether.h> 63 64#define SIN(s) ((struct sockaddr_in *)s) 65#define SDL(s) ((struct sockaddr_dl *)s) 66 67SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 68 69/* timer values */ 70static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 71static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 72static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 73 74SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 75 &arpt_prune, 0, ""); 76SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 77 &arpt_keep, 0, ""); 78SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 79 &arpt_down, 0, ""); 80 81#define rt_expire rt_rmx.rmx_expire 82 83struct llinfo_arp { 84 LIST_ENTRY(llinfo_arp) la_le; 85 struct rtentry *la_rt; 86 struct mbuf *la_hold; /* last packet until resolved/timeout */ 87 long la_asked; /* last time we QUERIED for this addr */ 88#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 89}; 90 91static LIST_HEAD(, llinfo_arp) llinfo_arp; 92 93struct ifqueue arpintrq = {0, 0, 0, 50}; 94static int arp_inuse, arp_allocated; 95 96static int arp_maxtries = 5; 97static int useloopback = 1; /* use loopback interface for local traffic */ 98static int arp_proxyall = 0; 99 100SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 101 &arp_maxtries, 0, ""); 102SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 103 &useloopback, 0, ""); 104SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 105 &arp_proxyall, 0, ""); 106 107static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 108static void arprequest __P((struct arpcom *, 109 struct in_addr *, struct in_addr *, u_char *)); 110static void arpintr __P((void)); 111static void arptfree __P((struct llinfo_arp *)); 112static void arptimer __P((void *)); 113static struct llinfo_arp 114 *arplookup __P((u_long, int, int)); 115#ifdef INET 116static void in_arpinput __P((struct mbuf *)); 117#endif 118 119/* 120 * Timeout routine. Age arp_tab entries periodically. 121 */ 122/* ARGSUSED */ 123static void 124arptimer(ignored_arg) 125 void *ignored_arg; 126{ 127 int s = splnet(); 128 register struct llinfo_arp *la = llinfo_arp.lh_first; 129 struct llinfo_arp *ola; 130 131 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 132 while ((ola = la) != 0) { 133 register struct rtentry *rt = la->la_rt; 134 la = la->la_le.le_next; 135 if (rt->rt_expire && rt->rt_expire <= time_second) 136 arptfree(ola); /* timer has expired, clear */ 137 } 138 splx(s); 139} 140 141/* 142 * Parallel to llc_rtrequest. 143 */ 144static void 145arp_rtrequest(req, rt, sa) 146 int req; 147 register struct rtentry *rt; 148 struct sockaddr *sa; 149{ 150 register struct sockaddr *gate = rt->rt_gateway; 151 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 152 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 153 static int arpinit_done; 154 155 if (!arpinit_done) { 156 arpinit_done = 1; 157 LIST_INIT(&llinfo_arp); 158 timeout(arptimer, (caddr_t)0, hz); 159 } 160 if (rt->rt_flags & RTF_GATEWAY) 161 return; 162 switch (req) { 163 164 case RTM_ADD: 165 /* 166 * XXX: If this is a manually added route to interface 167 * such as older version of routed or gated might provide, 168 * restore cloning bit. 169 */ 170 if ((rt->rt_flags & RTF_HOST) == 0 && 171 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 172 rt->rt_flags |= RTF_CLONING; 173 if (rt->rt_flags & RTF_CLONING) { 174 /* 175 * Case 1: This route should come from a route to iface. 176 */ 177 rt_setgate(rt, rt_key(rt), 178 (struct sockaddr *)&null_sdl); 179 gate = rt->rt_gateway; 180 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 181 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 182 rt->rt_expire = time_second; 183 break; 184 } 185 /* Announce a new entry if requested. */ 186 if (rt->rt_flags & RTF_ANNOUNCE) 187 arprequest((struct arpcom *)rt->rt_ifp, 188 &SIN(rt_key(rt))->sin_addr, 189 &SIN(rt_key(rt))->sin_addr, 190 (u_char *)LLADDR(SDL(gate))); 191 /*FALLTHROUGH*/ 192 case RTM_RESOLVE: 193 if (gate->sa_family != AF_LINK || 194 gate->sa_len < sizeof(null_sdl)) { 195 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 196 break; 197 } 198 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 199 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 200 if (la != 0) 201 break; /* This happens on a route change */ 202 /* 203 * Case 2: This route may come from cloning, or a manual route 204 * add with a LL address. 205 */ 206 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 207 rt->rt_llinfo = (caddr_t)la; 208 if (la == 0) { 209 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 210 break; 211 } 212 arp_inuse++, arp_allocated++; 213 Bzero(la, sizeof(*la)); 214 la->la_rt = rt; 215 rt->rt_flags |= RTF_LLINFO; 216 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 217 218#ifdef INET 219 /* 220 * This keeps the multicast addresses from showing up 221 * in `arp -a' listings as unresolved. It's not actually 222 * functional. Then the same for broadcast. 223 */ 224 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 225 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 226 LLADDR(SDL(gate))); 227 SDL(gate)->sdl_alen = 6; 228 rt->rt_expire = 0; 229 } 230 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 231 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 232 SDL(gate)->sdl_alen = 6; 233 rt->rt_expire = 0; 234 } 235#endif 236 237 if (SIN(rt_key(rt))->sin_addr.s_addr == 238 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 239 /* 240 * This test used to be 241 * if (loif.if_flags & IFF_UP) 242 * It allowed local traffic to be forced 243 * through the hardware by configuring the loopback down. 244 * However, it causes problems during network configuration 245 * for boards that can't receive packets they send. 246 * It is now necessary to clear "useloopback" and remove 247 * the route to force traffic out to the hardware. 248 */ 249 rt->rt_expire = 0; 250 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 251 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 252 if (useloopback) 253 rt->rt_ifp = loif; 254 255 } 256 break; 257 258 case RTM_DELETE: 259 if (la == 0) 260 break; 261 arp_inuse--; 262 LIST_REMOVE(la, la_le); 263 rt->rt_llinfo = 0; 264 rt->rt_flags &= ~RTF_LLINFO; 265 if (la->la_hold) 266 m_freem(la->la_hold); 267 Free((caddr_t)la); 268 } 269} 270 271/* 272 * Broadcast an ARP request. Caller specifies: 273 * - arp header source ip address 274 * - arp header target ip address 275 * - arp header source ethernet address 276 */ 277static void 278arprequest(ac, sip, tip, enaddr) 279 register struct arpcom *ac; 280 register struct in_addr *sip, *tip; 281 register u_char *enaddr; 282{ 283 register struct mbuf *m; 284 register struct ether_header *eh; 285 register struct ether_arp *ea; 286 struct sockaddr sa; 287 288 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 289 return; 290 m->m_len = sizeof(*ea); 291 m->m_pkthdr.len = sizeof(*ea); 292 MH_ALIGN(m, sizeof(*ea)); 293 ea = mtod(m, struct ether_arp *); 294 eh = (struct ether_header *)sa.sa_data; 295 bzero((caddr_t)ea, sizeof (*ea)); 296 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 297 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 298 ea->arp_hrd = htons(ARPHRD_ETHER); 299 ea->arp_pro = htons(ETHERTYPE_IP); 300 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 301 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 302 ea->arp_op = htons(ARPOP_REQUEST); 303 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 304 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 305 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 306 sa.sa_family = AF_UNSPEC; 307 sa.sa_len = sizeof(sa); 308 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 309} 310 311/* 312 * Resolve an IP address into an ethernet address. If success, 313 * desten is filled in. If there is no entry in arptab, 314 * set one up and broadcast a request for the IP address. 315 * Hold onto this mbuf and resend it once the address 316 * is finally resolved. A return value of 1 indicates 317 * that desten has been filled in and the packet should be sent 318 * normally; a 0 return indicates that the packet has been 319 * taken over here, either now or for later transmission. 320 */ 321int 322arpresolve(ac, rt, m, dst, desten, rt0) 323 register struct arpcom *ac; 324 register struct rtentry *rt; 325 struct mbuf *m; 326 register struct sockaddr *dst; 327 register u_char *desten; 328 struct rtentry *rt0; 329{ 330 register struct llinfo_arp *la; 331 struct sockaddr_dl *sdl; 332 333 if (m->m_flags & M_BCAST) { /* broadcast */ 334 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 335 return (1); 336 } 337 if (m->m_flags & M_MCAST) { /* multicast */ 338 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 339 return(1); 340 } 341 if (rt) 342 la = (struct llinfo_arp *)rt->rt_llinfo; 343 if (la == 0) { 344 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 345 if (la) 346 rt = la->la_rt; 347 } 348 if (la == 0 || rt == 0) { 349 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 350 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 351 rt ? "rt" : ""); 352 m_freem(m); 353 return (0); 354 } 355 sdl = SDL(rt->rt_gateway); 356 /* 357 * Check the address family and length is valid, the address 358 * is resolved; otherwise, try to resolve. 359 */ 360 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 361 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 362 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 363 return 1; 364 } 365 /* 366 * There is an arptab entry, but no ethernet address 367 * response yet. Replace the held mbuf with this 368 * latest one. 369 */ 370 if (la->la_hold) 371 m_freem(la->la_hold); 372 la->la_hold = m; 373 if (rt->rt_expire) { 374 rt->rt_flags &= ~RTF_REJECT; 375 if (la->la_asked == 0 || rt->rt_expire != time_second) { 376 rt->rt_expire = time_second; 377 if (la->la_asked++ < arp_maxtries) 378 arprequest(ac, 379 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 380 &SIN(dst)->sin_addr, ac->ac_enaddr); 381 else { 382 rt->rt_flags |= RTF_REJECT; 383 rt->rt_expire += arpt_down; 384 la->la_asked = 0; 385 } 386 387 } 388 } 389 return (0); 390} 391 392/* 393 * Common length and type checks are done here, 394 * then the protocol-specific routine is called. 395 */ 396static void 397arpintr() 398{ 399 register struct mbuf *m; 400 register struct arphdr *ar; 401 int s; 402 403 while (arpintrq.ifq_head) { 404 s = splimp(); 405 IF_DEQUEUE(&arpintrq, m); 406 splx(s); 407 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 408 panic("arpintr"); 409 if (m->m_len >= sizeof(struct arphdr) && 410 (ar = mtod(m, struct arphdr *)) && 411 ntohs(ar->ar_hrd) == ARPHRD_ETHER && 412 m->m_len >= 413 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 414 415 switch (ntohs(ar->ar_pro)) { 416 417#ifdef INET 418 case ETHERTYPE_IP: 419 in_arpinput(m); 420 continue; 421#endif 422 } 423 m_freem(m); 424 } 425} 426 427NETISR_SET(NETISR_ARP, arpintr); 428 429 430#ifdef INET 431/* 432 * ARP for Internet protocols on 10 Mb/s Ethernet. 433 * Algorithm is that given in RFC 826. 434 * In addition, a sanity check is performed on the sender 435 * protocol address, to catch impersonators. 436 * We no longer handle negotiations for use of trailer protocol: 437 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 438 * along with IP replies if we wanted trailers sent to us, 439 * and also sent them in response to IP replies. 440 * This allowed either end to announce the desire to receive 441 * trailer packets. 442 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 443 * but formerly didn't normally send requests. 444 */ 445static void 446in_arpinput(m) 447 struct mbuf *m; 448{ 449 register struct ether_arp *ea; 450 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 451 struct ether_header *eh; 452 register struct llinfo_arp *la = 0; 453 register struct rtentry *rt; 454 struct in_ifaddr *ia, *maybe_ia = 0; 455 struct sockaddr_dl *sdl; 456 struct sockaddr sa; 457 struct in_addr isaddr, itaddr, myaddr; 458 int op; 459 460 ea = mtod(m, struct ether_arp *); 461 op = ntohs(ea->arp_op); 462 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 463 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 464 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 465#ifdef BRIDGE 466 /* 467 * For a bridge, we want to check the address irrespective 468 * of the receive interface. (This will change slightly 469 * when we have clusters of interfaces). 470 */ 471 { 472#else 473 if (ia->ia_ifp == &ac->ac_if) { 474#endif 475 maybe_ia = ia; 476 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 477 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 478 break; 479 } 480 if (maybe_ia == 0) { 481 m_freem(m); 482 return; 483 } 484 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 485 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 486 sizeof (ea->arp_sha))) { 487 m_freem(m); /* it's from me, ignore it. */ 488 return; 489 } 490 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 491 sizeof (ea->arp_sha))) { 492 log(LOG_ERR, 493 "arp: ether address is broadcast for IP address %s!\n", 494 inet_ntoa(isaddr)); 495 m_freem(m); 496 return; 497 } 498 if (isaddr.s_addr == myaddr.s_addr) { 499 log(LOG_ERR, 500 "arp: %6D is using my IP address %s!\n", 501 ea->arp_sha, ":", inet_ntoa(isaddr)); 502 itaddr = myaddr; 503 goto reply; 504 } 505 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 506 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 507#ifndef BRIDGE /* the following is not an error when doing bridging */ 508 if (rt->rt_ifp != &ac->ac_if) { 509 log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 510 inet_ntoa(isaddr), 511 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 512 ea->arp_sha, ":", 513 ac->ac_if.if_name, ac->ac_if.if_unit); 514 goto reply; 515 } 516#endif 517 if (sdl->sdl_alen && 518 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) 519 if (rt->rt_expire) 520 log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 521 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 522 ea->arp_sha, ":", 523 ac->ac_if.if_name, ac->ac_if.if_unit); 524 else { 525 log(LOG_ERR, 526 "arp: %6D attempts to modify permanent entry for %s on %s%d", 527 ea->arp_sha, ":", inet_ntoa(isaddr), 528 ac->ac_if.if_name, ac->ac_if.if_unit); 529 goto reply; 530 } 531 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 532 sdl->sdl_alen = sizeof(ea->arp_sha); 533 if (rt->rt_expire) 534 rt->rt_expire = time_second + arpt_keep; 535 rt->rt_flags &= ~RTF_REJECT; 536 la->la_asked = 0; 537 if (la->la_hold) { 538 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 539 rt_key(rt), rt); 540 la->la_hold = 0; 541 } 542 } 543reply: 544 if (op != ARPOP_REQUEST) { 545 m_freem(m); 546 return; 547 } 548 if (itaddr.s_addr == myaddr.s_addr) { 549 /* I am the target */ 550 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 551 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 552 } else { 553 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 554 if (la == NULL) { 555 struct sockaddr_in sin; 556 557 if (!arp_proxyall) { 558 m_freem(m); 559 return; 560 } 561 562 bzero(&sin, sizeof sin); 563 sin.sin_family = AF_INET; 564 sin.sin_len = sizeof sin; 565 sin.sin_addr = itaddr; 566 567 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 568 if (!rt) { 569 m_freem(m); 570 return; 571 } 572 /* 573 * Don't send proxies for nodes on the same interface 574 * as this one came out of, or we'll get into a fight 575 * over who claims what Ether address. 576 */ 577 if (rt->rt_ifp == &ac->ac_if) { 578 rtfree(rt); 579 m_freem(m); 580 return; 581 } 582 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 583 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 584 rtfree(rt); 585#ifdef DEBUG_PROXY 586 printf("arp: proxying for %s\n", 587 inet_ntoa(itaddr)); 588#endif 589 } else { 590 rt = la->la_rt; 591 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 592 sdl = SDL(rt->rt_gateway); 593 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 594 } 595 } 596 597 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 598 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 599 ea->arp_op = htons(ARPOP_REPLY); 600 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 601 eh = (struct ether_header *)sa.sa_data; 602 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 603 eh->ether_type = htons(ETHERTYPE_ARP); 604 sa.sa_family = AF_UNSPEC; 605 sa.sa_len = sizeof(sa); 606 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 607 return; 608} 609#endif 610 611/* 612 * Free an arp entry. 613 */ 614static void 615arptfree(la) 616 register struct llinfo_arp *la; 617{ 618 register struct rtentry *rt = la->la_rt; 619 register struct sockaddr_dl *sdl; 620 if (rt == 0) 621 panic("arptfree"); 622 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 623 sdl->sdl_family == AF_LINK) { 624 sdl->sdl_alen = 0; 625 la->la_asked = 0; 626 rt->rt_flags &= ~RTF_REJECT; 627 return; 628 } 629 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 630 0, (struct rtentry **)0); 631} 632/* 633 * Lookup or enter a new address in arptab. 634 */ 635static struct llinfo_arp * 636arplookup(addr, create, proxy) 637 u_long addr; 638 int create, proxy; 639{ 640 register struct rtentry *rt; 641 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 642 const char *why = 0; 643 644 sin.sin_addr.s_addr = addr; 645 sin.sin_other = proxy ? SIN_PROXY : 0; 646 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 647 if (rt == 0) 648 return (0); 649 rt->rt_refcnt--; 650 651 if (rt->rt_flags & RTF_GATEWAY) 652 why = "host is not on local network"; 653 else if ((rt->rt_flags & RTF_LLINFO) == 0) 654 why = "could not allocate llinfo"; 655 else if (rt->rt_gateway->sa_family != AF_LINK) 656 why = "gateway route is not ours"; 657 658 if (why && create) { 659 log(LOG_DEBUG, "arplookup %s failed: %s\n", 660 inet_ntoa(sin.sin_addr), why); 661 return 0; 662 } else if (why) { 663 return 0; 664 } 665 return ((struct llinfo_arp *)rt->rt_llinfo); 666} 667 668void 669arp_ifinit(ac, ifa) 670 struct arpcom *ac; 671 struct ifaddr *ifa; 672{ 673 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 674 arprequest(ac, &IA_SIN(ifa)->sin_addr, 675 &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 676 ifa->ifa_rtrequest = arp_rtrequest; 677 ifa->ifa_flags |= RTF_CLONING; 678} 679