if_ether.c revision 58499
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: head/sys/netinet/if_ether.c 58499 2000-03-23 18:58:59Z dillon $ 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 72SYSCTL_DECL(_net_link_ether); 73SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 74 75/* timer values */ 76static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 77static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 78static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 79 80SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 81 &arpt_prune, 0, ""); 82SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 83 &arpt_keep, 0, ""); 84SYSCTL_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 89struct 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 97static LIST_HEAD(, llinfo_arp) llinfo_arp; 98 99struct ifqueue arpintrq = {0, 0, 0, 50}; 100static int arp_inuse, arp_allocated; 101 102static int arp_maxtries = 5; 103static int useloopback = 1; /* use loopback interface for local traffic */ 104static int arp_proxyall = 0; 105 106SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 107 &arp_maxtries, 0, ""); 108SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 109 &useloopback, 0, ""); 110SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 111 &arp_proxyall, 0, ""); 112 113static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 114static void arprequest __P((struct arpcom *, 115 struct in_addr *, struct in_addr *, u_char *)); 116static void arpintr __P((void)); 117static void arptfree __P((struct llinfo_arp *)); 118static void arptimer __P((void *)); 119static struct llinfo_arp 120 *arplookup __P((u_long, int, int)); 121#ifdef INET 122static void in_arpinput __P((struct mbuf *)); 123#endif 124 125/* 126 * Timeout routine. Age arp_tab entries periodically. 127 */ 128/* ARGSUSED */ 129static void 130arptimer(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 */ 150static void 151arp_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 */ 284static void 285arprequest(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 */ 357int 358arpresolve(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 */ 432static void 433arpintr() 434{ 435 register struct mbuf *m, *m0; 436 register struct arphdr *ar; 437 int s, ml; 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."); 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 (%2D)", 457 (unsigned char *)&ar->ar_hrd, ""); 458 m_freem(m); 459 continue; 460 } 461 462 m0 = m; 463 ml = 0; 464 while (m0 != NULL) { 465 ml += m0->m_len; /* wanna implement m_size?? */ 466 m0 = m0->m_next; 467 } 468 469 if (ml < sizeof(struct arphdr) + 2 * ar->ar_hln 470 + 2 * ar->ar_pln) { 471 log(LOG_ERR, "arp: runt packet."); 472 m_freem(m); 473 continue; 474 } 475 476 switch (ntohs(ar->ar_pro)) { 477#ifdef INET 478 case ETHERTYPE_IP: 479 in_arpinput(m); 480 continue; 481#endif 482 } 483 m_freem(m); 484 } 485} 486 487#ifdef INET 488/* 489 * ARP for Internet protocols on 10 Mb/s Ethernet. 490 * Algorithm is that given in RFC 826. 491 * In addition, a sanity check is performed on the sender 492 * protocol address, to catch impersonators. 493 * We no longer handle negotiations for use of trailer protocol: 494 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 495 * along with IP replies if we wanted trailers sent to us, 496 * and also sent them in response to IP replies. 497 * This allowed either end to announce the desire to receive 498 * trailer packets. 499 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 500 * but formerly didn't normally send requests. 501 */ 502static void 503in_arpinput(m) 504 struct mbuf *m; 505{ 506 register struct ether_arp *ea; 507 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 508 struct ether_header *eh; 509 struct iso88025_header *th = (struct iso88025_header *)0; 510 register struct llinfo_arp *la = 0; 511 register struct rtentry *rt; 512 struct in_ifaddr *ia, *maybe_ia = 0; 513 struct sockaddr_dl *sdl; 514 struct sockaddr sa; 515 struct in_addr isaddr, itaddr, myaddr; 516 int op, rif_len; 517 518 ea = mtod(m, struct ether_arp *); 519 op = ntohs(ea->arp_op); 520 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 521 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 522 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 523#ifdef BRIDGE 524 /* 525 * For a bridge, we want to check the address irrespective 526 * of the receive interface. (This will change slightly 527 * when we have clusters of interfaces). 528 */ 529 { 530#else 531 if (ia->ia_ifp == &ac->ac_if) { 532#endif 533 maybe_ia = ia; 534 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 535 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 536 break; 537 } 538 if (maybe_ia == 0) { 539 m_freem(m); 540 return; 541 } 542 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 543 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 544 sizeof (ea->arp_sha))) { 545 m_freem(m); /* it's from me, ignore it. */ 546 return; 547 } 548 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 549 sizeof (ea->arp_sha))) { 550 log(LOG_ERR, 551 "arp: ether address is broadcast for IP address %s!\n", 552 inet_ntoa(isaddr)); 553 m_freem(m); 554 return; 555 } 556 if (isaddr.s_addr == myaddr.s_addr) { 557 log(LOG_ERR, 558 "arp: %6D is using my IP address %s!\n", 559 ea->arp_sha, ":", inet_ntoa(isaddr)); 560 itaddr = myaddr; 561 goto reply; 562 } 563 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 564 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 565#ifndef BRIDGE /* the following is not an error when doing bridging */ 566 if (rt->rt_ifp != &ac->ac_if) { 567 log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 568 inet_ntoa(isaddr), 569 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 570 ea->arp_sha, ":", 571 ac->ac_if.if_name, ac->ac_if.if_unit); 572 goto reply; 573 } 574#endif 575 if (sdl->sdl_alen && 576 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 577 if (rt->rt_expire) 578 log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 579 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 580 ea->arp_sha, ":", 581 ac->ac_if.if_name, ac->ac_if.if_unit); 582 else { 583 log(LOG_ERR, 584 "arp: %6D attempts to modify permanent entry for %s on %s%d\n", 585 ea->arp_sha, ":", inet_ntoa(isaddr), 586 ac->ac_if.if_name, ac->ac_if.if_unit); 587 goto reply; 588 } 589 } 590 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 591 sdl->sdl_alen = sizeof(ea->arp_sha); 592 sdl->sdl_rcf = (u_short)0; 593 /* 594 * If we receive an arp from a token-ring station over 595 * a token-ring nic then try to save the source 596 * routing info. 597 */ 598 if (ac->ac_if.if_type == IFT_ISO88025) { 599 th = (struct iso88025_header *)m->m_pkthdr.header; 600 rif_len = TR_RCF_RIFLEN(th->rcf); 601 if ((th->iso88025_shost[0] & TR_RII) && 602 (rif_len > 2)) { 603 sdl->sdl_rcf = th->rcf; 604 sdl->sdl_rcf ^= htons(TR_RCF_DIR); 605 memcpy(sdl->sdl_route, th->rd, rif_len - 2); 606 sdl->sdl_rcf &= ~htons(TR_RCF_BCST_MASK); 607 /* 608 * Set up source routing information for 609 * reply packet (XXX) 610 */ 611 m->m_data -= rif_len; 612 m->m_len += rif_len; 613 m->m_pkthdr.len += rif_len; 614 } else { 615 th->iso88025_shost[0] &= ~TR_RII; 616 } 617 m->m_data -= 8; 618 m->m_len += 8; 619 m->m_pkthdr.len += 8; 620 th->rcf = sdl->sdl_rcf; 621 } else { 622 sdl->sdl_rcf = (u_short)0; 623 } 624 if (rt->rt_expire) 625 rt->rt_expire = time_second + arpt_keep; 626 rt->rt_flags &= ~RTF_REJECT; 627 la->la_asked = 0; 628 if (la->la_hold) { 629 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 630 rt_key(rt), rt); 631 la->la_hold = 0; 632 } 633 } 634reply: 635 if (op != ARPOP_REQUEST) { 636 m_freem(m); 637 return; 638 } 639 if (itaddr.s_addr == myaddr.s_addr) { 640 /* I am the target */ 641 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 642 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 643 } else { 644 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 645 if (la == NULL) { 646 struct sockaddr_in sin; 647 648 if (!arp_proxyall) { 649 m_freem(m); 650 return; 651 } 652 653 bzero(&sin, sizeof sin); 654 sin.sin_family = AF_INET; 655 sin.sin_len = sizeof sin; 656 sin.sin_addr = itaddr; 657 658 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 659 if (!rt) { 660 m_freem(m); 661 return; 662 } 663 /* 664 * Don't send proxies for nodes on the same interface 665 * as this one came out of, or we'll get into a fight 666 * over who claims what Ether address. 667 */ 668 if (rt->rt_ifp == &ac->ac_if) { 669 rtfree(rt); 670 m_freem(m); 671 return; 672 } 673 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 674 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 675 rtfree(rt); 676#ifdef DEBUG_PROXY 677 printf("arp: proxying for %s\n", 678 inet_ntoa(itaddr)); 679#endif 680 } else { 681 rt = la->la_rt; 682 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 683 sdl = SDL(rt->rt_gateway); 684 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 685 } 686 } 687 688 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 689 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 690 ea->arp_op = htons(ARPOP_REPLY); 691 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 692 switch (ac->ac_if.if_type) { 693 case IFT_ISO88025: 694 /* Re-arrange the source/dest address */ 695 memcpy(th->iso88025_dhost, th->iso88025_shost, 696 sizeof(th->iso88025_dhost)); 697 memcpy(th->iso88025_shost, ac->ac_enaddr, 698 sizeof(th->iso88025_shost)); 699 /* Set the source routing bit if neccesary */ 700 if (th->iso88025_dhost[0] & TR_RII) { 701 th->iso88025_dhost[0] &= ~TR_RII; 702 if (TR_RCF_RIFLEN(th->rcf) > 2) 703 th->iso88025_shost[0] |= TR_RII; 704 } 705 /* Copy the addresses, ac and fc into sa_data */ 706 memcpy(sa.sa_data, th->iso88025_dhost, 707 sizeof(th->iso88025_dhost) * 2); 708 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = TR_AC; 709 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = TR_LLC_FRAME; 710 break; 711 case IFT_ETHER: 712 case IFT_FDDI: 713 /* 714 * May not be correct for types not explictly 715 * listed, but it is our best guess. 716 */ 717 default: 718 eh = (struct ether_header *)sa.sa_data; 719 (void)memcpy(eh->ether_dhost, ea->arp_tha, 720 sizeof(eh->ether_dhost)); 721 eh->ether_type = htons(ETHERTYPE_ARP); 722 break; 723 } 724 sa.sa_family = AF_UNSPEC; 725 sa.sa_len = sizeof(sa); 726 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 727 return; 728} 729#endif 730 731/* 732 * Free an arp entry. 733 */ 734static void 735arptfree(la) 736 register struct llinfo_arp *la; 737{ 738 register struct rtentry *rt = la->la_rt; 739 register struct sockaddr_dl *sdl; 740 if (rt == 0) 741 panic("arptfree"); 742 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 743 sdl->sdl_family == AF_LINK) { 744 sdl->sdl_alen = 0; 745 la->la_asked = 0; 746 rt->rt_flags &= ~RTF_REJECT; 747 return; 748 } 749 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 750 0, (struct rtentry **)0); 751} 752/* 753 * Lookup or enter a new address in arptab. 754 */ 755static struct llinfo_arp * 756arplookup(addr, create, proxy) 757 u_long addr; 758 int create, proxy; 759{ 760 register struct rtentry *rt; 761 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 762 const char *why = 0; 763 764 sin.sin_addr.s_addr = addr; 765 sin.sin_other = proxy ? SIN_PROXY : 0; 766 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 767 if (rt == 0) 768 return (0); 769 rt->rt_refcnt--; 770 771 if (rt->rt_flags & RTF_GATEWAY) 772 why = "host is not on local network"; 773 else if ((rt->rt_flags & RTF_LLINFO) == 0) 774 why = "could not allocate llinfo"; 775 else if (rt->rt_gateway->sa_family != AF_LINK) 776 why = "gateway route is not ours"; 777 778 if (why && create) { 779 log(LOG_DEBUG, "arplookup %s failed: %s\n", 780 inet_ntoa(sin.sin_addr), why); 781 return 0; 782 } else if (why) { 783 return 0; 784 } 785 return ((struct llinfo_arp *)rt->rt_llinfo); 786} 787 788void 789arp_ifinit(ac, ifa) 790 struct arpcom *ac; 791 struct ifaddr *ifa; 792{ 793 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 794 arprequest(ac, &IA_SIN(ifa)->sin_addr, 795 &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 796 ifa->ifa_rtrequest = arp_rtrequest; 797 ifa->ifa_flags |= RTF_CLONING; 798} 799