if_ether.c revision 50512
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 50512 1999-08-28 14:57:12Z lile $ 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 62#include <netinet/in.h> 63#include <netinet/in_var.h> 64#include <netinet/if_ether.h> 65 66#include <net/iso88025.h> 67 68#define SIN(s) ((struct sockaddr_in *)s) 69#define SDL(s) ((struct sockaddr_dl *)s) 70 71SYSCTL_DECL(_net_link_ether); 72SYSCTL_NODE(_net_link_ether, PF_INET, inet, CTLFLAG_RW, 0, ""); 73 74/* timer values */ 75static int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 76static int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 77static int arpt_down = 20; /* once declared down, don't send for 20 sec */ 78 79SYSCTL_INT(_net_link_ether_inet, OID_AUTO, prune_intvl, CTLFLAG_RW, 80 &arpt_prune, 0, ""); 81SYSCTL_INT(_net_link_ether_inet, OID_AUTO, max_age, CTLFLAG_RW, 82 &arpt_keep, 0, ""); 83SYSCTL_INT(_net_link_ether_inet, OID_AUTO, host_down_time, CTLFLAG_RW, 84 &arpt_down, 0, ""); 85 86#define rt_expire rt_rmx.rmx_expire 87 88struct llinfo_arp { 89 LIST_ENTRY(llinfo_arp) la_le; 90 struct rtentry *la_rt; 91 struct mbuf *la_hold; /* last packet until resolved/timeout */ 92 long la_asked; /* last time we QUERIED for this addr */ 93#define la_timer la_rt->rt_rmx.rmx_expire /* deletion time in seconds */ 94}; 95 96static LIST_HEAD(, llinfo_arp) llinfo_arp; 97 98struct ifqueue arpintrq = {0, 0, 0, 50}; 99static int arp_inuse, arp_allocated; 100 101static int arp_maxtries = 5; 102static int useloopback = 1; /* use loopback interface for local traffic */ 103static int arp_proxyall = 0; 104 105SYSCTL_INT(_net_link_ether_inet, OID_AUTO, maxtries, CTLFLAG_RW, 106 &arp_maxtries, 0, ""); 107SYSCTL_INT(_net_link_ether_inet, OID_AUTO, useloopback, CTLFLAG_RW, 108 &useloopback, 0, ""); 109SYSCTL_INT(_net_link_ether_inet, OID_AUTO, proxyall, CTLFLAG_RW, 110 &arp_proxyall, 0, ""); 111 112static void arp_rtrequest __P((int, struct rtentry *, struct sockaddr *)); 113static void arprequest __P((struct arpcom *, 114 struct in_addr *, struct in_addr *, u_char *)); 115static void arpintr __P((void)); 116static void arptfree __P((struct llinfo_arp *)); 117static void arptimer __P((void *)); 118static struct llinfo_arp 119 *arplookup __P((u_long, int, int)); 120#ifdef INET 121static void in_arpinput __P((struct mbuf *)); 122#endif 123 124/* 125 * Timeout routine. Age arp_tab entries periodically. 126 */ 127/* ARGSUSED */ 128static void 129arptimer(ignored_arg) 130 void *ignored_arg; 131{ 132 int s = splnet(); 133 register struct llinfo_arp *la = llinfo_arp.lh_first; 134 struct llinfo_arp *ola; 135 136 timeout(arptimer, (caddr_t)0, arpt_prune * hz); 137 while ((ola = la) != 0) { 138 register struct rtentry *rt = la->la_rt; 139 la = la->la_le.le_next; 140 if (rt->rt_expire && rt->rt_expire <= time_second) 141 arptfree(ola); /* timer has expired, clear */ 142 } 143 splx(s); 144} 145 146/* 147 * Parallel to llc_rtrequest. 148 */ 149static void 150arp_rtrequest(req, rt, sa) 151 int req; 152 register struct rtentry *rt; 153 struct sockaddr *sa; 154{ 155 register struct sockaddr *gate = rt->rt_gateway; 156 register struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 157 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 158 static int arpinit_done; 159 160 if (!arpinit_done) { 161 arpinit_done = 1; 162 LIST_INIT(&llinfo_arp); 163 timeout(arptimer, (caddr_t)0, hz); 164 } 165 if (rt->rt_flags & RTF_GATEWAY) 166 return; 167 switch (req) { 168 169 case RTM_ADD: 170 /* 171 * XXX: If this is a manually added route to interface 172 * such as older version of routed or gated might provide, 173 * restore cloning bit. 174 */ 175 if ((rt->rt_flags & RTF_HOST) == 0 && 176 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 177 rt->rt_flags |= RTF_CLONING; 178 if (rt->rt_flags & RTF_CLONING) { 179 /* 180 * Case 1: This route should come from a route to iface. 181 */ 182 rt_setgate(rt, rt_key(rt), 183 (struct sockaddr *)&null_sdl); 184 gate = rt->rt_gateway; 185 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 186 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 187 rt->rt_expire = time_second; 188 break; 189 } 190 /* Announce a new entry if requested. */ 191 if (rt->rt_flags & RTF_ANNOUNCE) 192 arprequest((struct arpcom *)rt->rt_ifp, 193 &SIN(rt_key(rt))->sin_addr, 194 &SIN(rt_key(rt))->sin_addr, 195 (u_char *)LLADDR(SDL(gate))); 196 /*FALLTHROUGH*/ 197 case RTM_RESOLVE: 198 if (gate->sa_family != AF_LINK || 199 gate->sa_len < sizeof(null_sdl)) { 200 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 201 break; 202 } 203 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 204 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 205 if (la != 0) 206 break; /* This happens on a route change */ 207 /* 208 * Case 2: This route may come from cloning, or a manual route 209 * add with a LL address. 210 */ 211 R_Malloc(la, struct llinfo_arp *, sizeof(*la)); 212 rt->rt_llinfo = (caddr_t)la; 213 if (la == 0) { 214 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 215 break; 216 } 217 arp_inuse++, arp_allocated++; 218 Bzero(la, sizeof(*la)); 219 la->la_rt = rt; 220 rt->rt_flags |= RTF_LLINFO; 221 LIST_INSERT_HEAD(&llinfo_arp, la, la_le); 222 223#ifdef INET 224 /* 225 * This keeps the multicast addresses from showing up 226 * in `arp -a' listings as unresolved. It's not actually 227 * functional. Then the same for broadcast. 228 */ 229 if (IN_MULTICAST(ntohl(SIN(rt_key(rt))->sin_addr.s_addr))) { 230 ETHER_MAP_IP_MULTICAST(&SIN(rt_key(rt))->sin_addr, 231 LLADDR(SDL(gate))); 232 SDL(gate)->sdl_alen = 6; 233 rt->rt_expire = 0; 234 } 235 if (in_broadcast(SIN(rt_key(rt))->sin_addr, rt->rt_ifp)) { 236 memcpy(LLADDR(SDL(gate)), etherbroadcastaddr, 6); 237 SDL(gate)->sdl_alen = 6; 238 rt->rt_expire = 0; 239 } 240#endif 241 242 if (SIN(rt_key(rt))->sin_addr.s_addr == 243 (IA_SIN(rt->rt_ifa))->sin_addr.s_addr) { 244 /* 245 * This test used to be 246 * if (loif.if_flags & IFF_UP) 247 * It allowed local traffic to be forced 248 * through the hardware by configuring the loopback down. 249 * However, it causes problems during network configuration 250 * for boards that can't receive packets they send. 251 * It is now necessary to clear "useloopback" and remove 252 * the route to force traffic out to the hardware. 253 */ 254 rt->rt_expire = 0; 255 Bcopy(((struct arpcom *)rt->rt_ifp)->ac_enaddr, 256 LLADDR(SDL(gate)), SDL(gate)->sdl_alen = 6); 257 if (useloopback) 258 rt->rt_ifp = loif; 259 260 } 261 break; 262 263 case RTM_DELETE: 264 if (la == 0) 265 break; 266 arp_inuse--; 267 LIST_REMOVE(la, la_le); 268 rt->rt_llinfo = 0; 269 rt->rt_flags &= ~RTF_LLINFO; 270 if (la->la_hold) 271 m_freem(la->la_hold); 272 Free((caddr_t)la); 273 } 274} 275 276/* 277 * Broadcast an ARP request. Caller specifies: 278 * - arp header source ip address 279 * - arp header target ip address 280 * - arp header source ethernet address 281 */ 282static void 283arprequest(ac, sip, tip, enaddr) 284 register struct arpcom *ac; 285 register struct in_addr *sip, *tip; 286 register u_char *enaddr; 287{ 288 register struct mbuf *m; 289 register struct ether_header *eh; 290 register struct ether_arp *ea; 291 struct sockaddr sa; 292 293 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 294 return; 295 m->m_pkthdr.rcvif = (struct ifnet *)0; 296 switch (ac->ac_if.if_type) { 297 case IFT_ETHER: 298 m->m_len = sizeof(*ea); 299 m->m_pkthdr.len = sizeof(*ea); 300 MH_ALIGN(m, sizeof(*ea)); 301 ea = mtod(m, struct ether_arp *); 302 eh = (struct ether_header *)sa.sa_data; 303 bzero((caddr_t)ea, sizeof (*ea)); 304 eh->ether_type = htons(ETHERTYPE_ARP); /* if_output will not swap */ 305 (void)memcpy(eh->ether_dhost, etherbroadcastaddr, sizeof(eh->ether_dhost)); 306 ea->arp_hrd = htons(ARPHRD_ETHER); 307 break; 308 case IFT_ISO88025: 309 m->m_len = sizeof(*ea) + 10; 310 m->m_pkthdr.len = sizeof(*ea) + 10; 311 MH_ALIGN(m, sizeof(*ea) + 10); 312 (void)memcpy(mtod(m, caddr_t), "\x82\x40\xaa\xaa\x03\x00\x00\x00\x08\x06", 10); 313 (void)memcpy(sa.sa_data, etherbroadcastaddr, 6); 314 (void)memcpy(sa.sa_data + 6, enaddr, 6); 315 sa.sa_data[6] |= 0x80; 316 sa.sa_data[12] = 0x10; 317 sa.sa_data[13] = 0x40; 318 ea = (struct ether_arp *)(mtod(m, char *) + 10); 319 bzero((caddr_t)ea, sizeof (*ea)); 320 ea->arp_hrd = htons(ARPHRD_IEEE802); 321 break; 322 default: 323 m_freem(m); 324 return; 325 } 326 ea->arp_pro = htons(ETHERTYPE_IP); 327 ea->arp_hln = sizeof(ea->arp_sha); /* hardware address length */ 328 ea->arp_pln = sizeof(ea->arp_spa); /* protocol address length */ 329 ea->arp_op = htons(ARPOP_REQUEST); 330 (void)memcpy(ea->arp_sha, enaddr, sizeof(ea->arp_sha)); 331 (void)memcpy(ea->arp_spa, sip, sizeof(ea->arp_spa)); 332 (void)memcpy(ea->arp_tpa, tip, sizeof(ea->arp_tpa)); 333 sa.sa_family = AF_UNSPEC; 334 sa.sa_len = sizeof(sa); 335 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 336} 337 338/* 339 * Resolve an IP address into an ethernet address. If success, 340 * desten is filled in. If there is no entry in arptab, 341 * set one up and broadcast a request for the IP address. 342 * Hold onto this mbuf and resend it once the address 343 * is finally resolved. A return value of 1 indicates 344 * that desten has been filled in and the packet should be sent 345 * normally; a 0 return indicates that the packet has been 346 * taken over here, either now or for later transmission. 347 */ 348int 349arpresolve(ac, rt, m, dst, desten, rt0) 350 register struct arpcom *ac; 351 register struct rtentry *rt; 352 struct mbuf *m; 353 register struct sockaddr *dst; 354 register u_char *desten; 355 struct rtentry *rt0; 356{ 357 register struct llinfo_arp *la = 0; 358 struct sockaddr_dl *sdl; 359 360 if (m->m_flags & M_BCAST) { /* broadcast */ 361 (void)memcpy(desten, etherbroadcastaddr, sizeof(etherbroadcastaddr)); 362 return (1); 363 } 364 if (m->m_flags & M_MCAST) { /* multicast */ 365 ETHER_MAP_IP_MULTICAST(&SIN(dst)->sin_addr, desten); 366 return(1); 367 } 368 if (rt) 369 la = (struct llinfo_arp *)rt->rt_llinfo; 370 if (la == 0) { 371 la = arplookup(SIN(dst)->sin_addr.s_addr, 1, 0); 372 if (la) 373 rt = la->la_rt; 374 } 375 if (la == 0 || rt == 0) { 376 log(LOG_DEBUG, "arpresolve: can't allocate llinfo for %s%s%s\n", 377 inet_ntoa(SIN(dst)->sin_addr), la ? "la" : "", 378 rt ? "rt" : ""); 379 m_freem(m); 380 return (0); 381 } 382 sdl = SDL(rt->rt_gateway); 383 /* 384 * Check the address family and length is valid, the address 385 * is resolved; otherwise, try to resolve. 386 */ 387 if ((rt->rt_expire == 0 || rt->rt_expire > time_second) && 388 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 389 bcopy(LLADDR(sdl), desten, sdl->sdl_alen); 390 return 1; 391 } 392 /* 393 * There is an arptab entry, but no ethernet address 394 * response yet. Replace the held mbuf with this 395 * latest one. 396 */ 397 if (la->la_hold) 398 m_freem(la->la_hold); 399 la->la_hold = m; 400 if (rt->rt_expire) { 401 rt->rt_flags &= ~RTF_REJECT; 402 if (la->la_asked == 0 || rt->rt_expire != time_second) { 403 rt->rt_expire = time_second; 404 if (la->la_asked++ < arp_maxtries) 405 arprequest(ac, 406 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 407 &SIN(dst)->sin_addr, ac->ac_enaddr); 408 else { 409 rt->rt_flags |= RTF_REJECT; 410 rt->rt_expire += arpt_down; 411 la->la_asked = 0; 412 } 413 414 } 415 } 416 return (0); 417} 418 419/* 420 * Common length and type checks are done here, 421 * then the protocol-specific routine is called. 422 */ 423static void 424arpintr() 425{ 426 register struct mbuf *m; 427 register struct arphdr *ar; 428 int s; 429 430 while (arpintrq.ifq_head) { 431 s = splimp(); 432 IF_DEQUEUE(&arpintrq, m); 433 splx(s); 434 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 435 panic("arpintr"); 436 if (m->m_len >= sizeof(struct arphdr) && 437 (ar = mtod(m, struct arphdr *)) && 438 (ntohs(ar->ar_hrd) == ARPHRD_ETHER || 439 ntohs(ar->ar_hrd) == ARPHRD_IEEE802) && 440 m->m_len >= 441 sizeof(struct arphdr) + 2 * ar->ar_hln + 2 * ar->ar_pln) 442 443 switch (ntohs(ar->ar_pro)) { 444 445#ifdef INET 446 case ETHERTYPE_IP: 447 in_arpinput(m); 448 continue; 449#endif 450 } 451 m_freem(m); 452 } 453} 454 455NETISR_SET(NETISR_ARP, arpintr); 456 457 458#ifdef INET 459/* 460 * ARP for Internet protocols on 10 Mb/s Ethernet. 461 * Algorithm is that given in RFC 826. 462 * In addition, a sanity check is performed on the sender 463 * protocol address, to catch impersonators. 464 * We no longer handle negotiations for use of trailer protocol: 465 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 466 * along with IP replies if we wanted trailers sent to us, 467 * and also sent them in response to IP replies. 468 * This allowed either end to announce the desire to receive 469 * trailer packets. 470 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 471 * but formerly didn't normally send requests. 472 */ 473static void 474in_arpinput(m) 475 struct mbuf *m; 476{ 477 register struct ether_arp *ea; 478 register struct arpcom *ac = (struct arpcom *)m->m_pkthdr.rcvif; 479 struct ether_header *eh; 480 struct iso88025_header *th = (struct iso88025_header *)0; 481 register struct llinfo_arp *la = 0; 482 register struct rtentry *rt; 483 struct in_ifaddr *ia, *maybe_ia = 0; 484 struct sockaddr_dl *sdl; 485 struct sockaddr sa; 486 struct in_addr isaddr, itaddr, myaddr; 487 int op; 488 489 ea = mtod(m, struct ether_arp *); 490 op = ntohs(ea->arp_op); 491 (void)memcpy(&isaddr, ea->arp_spa, sizeof (isaddr)); 492 (void)memcpy(&itaddr, ea->arp_tpa, sizeof (itaddr)); 493 for (ia = in_ifaddrhead.tqh_first; ia; ia = ia->ia_link.tqe_next) 494#ifdef BRIDGE 495 /* 496 * For a bridge, we want to check the address irrespective 497 * of the receive interface. (This will change slightly 498 * when we have clusters of interfaces). 499 */ 500 { 501#else 502 if (ia->ia_ifp == &ac->ac_if) { 503#endif 504 maybe_ia = ia; 505 if ((itaddr.s_addr == ia->ia_addr.sin_addr.s_addr) || 506 (isaddr.s_addr == ia->ia_addr.sin_addr.s_addr)) 507 break; 508 } 509 if (maybe_ia == 0) { 510 m_freem(m); 511 return; 512 } 513 myaddr = ia ? ia->ia_addr.sin_addr : maybe_ia->ia_addr.sin_addr; 514 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)ac->ac_enaddr, 515 sizeof (ea->arp_sha))) { 516 m_freem(m); /* it's from me, ignore it. */ 517 return; 518 } 519 if (!bcmp((caddr_t)ea->arp_sha, (caddr_t)etherbroadcastaddr, 520 sizeof (ea->arp_sha))) { 521 log(LOG_ERR, 522 "arp: ether address is broadcast for IP address %s!\n", 523 inet_ntoa(isaddr)); 524 m_freem(m); 525 return; 526 } 527 if (isaddr.s_addr == myaddr.s_addr) { 528 log(LOG_ERR, 529 "arp: %6D is using my IP address %s!\n", 530 ea->arp_sha, ":", inet_ntoa(isaddr)); 531 itaddr = myaddr; 532 goto reply; 533 } 534 la = arplookup(isaddr.s_addr, itaddr.s_addr == myaddr.s_addr, 0); 535 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 536#ifndef BRIDGE /* the following is not an error when doing bridging */ 537 if (rt->rt_ifp != &ac->ac_if) { 538 log(LOG_ERR, "arp: %s is on %s%d but got reply from %6D on %s%d\n", 539 inet_ntoa(isaddr), 540 rt->rt_ifp->if_name, rt->rt_ifp->if_unit, 541 ea->arp_sha, ":", 542 ac->ac_if.if_name, ac->ac_if.if_unit); 543 goto reply; 544 } 545#endif 546 if (sdl->sdl_alen && 547 bcmp((caddr_t)ea->arp_sha, LLADDR(sdl), sdl->sdl_alen)) { 548 if (rt->rt_expire) 549 log(LOG_INFO, "arp: %s moved from %6D to %6D on %s%d\n", 550 inet_ntoa(isaddr), (u_char *)LLADDR(sdl), ":", 551 ea->arp_sha, ":", 552 ac->ac_if.if_name, ac->ac_if.if_unit); 553 else { 554 log(LOG_ERR, 555 "arp: %6D attempts to modify permanent entry for %s on %s%d", 556 ea->arp_sha, ":", inet_ntoa(isaddr), 557 ac->ac_if.if_name, ac->ac_if.if_unit); 558 goto reply; 559 } 560 } 561 (void)memcpy(LLADDR(sdl), ea->arp_sha, sizeof(ea->arp_sha)); 562 sdl->sdl_alen = sizeof(ea->arp_sha); 563 sdl->sdl_rcf = NULL; 564 /* 565 * If we receive an arp from a token-ring station over 566 * a token-ring nic then try to save the source 567 * routing info. 568 */ 569 if (ac->ac_if.if_type == IFT_ISO88025) { 570 th = (struct iso88025_header *)m->m_pkthdr.header; 571 if ((th->iso88025_shost[0] & 0x80) && 572 ((th->rcf & 0x001f) > 2)) { 573 sdl->sdl_rcf = (th->rcf & 0x8000) ? (th->rcf & 0x7fff) : 574 (th->rcf | 0x8000); 575 memcpy(sdl->sdl_route, th->rseg, (th->rcf & 0x001f) - 2); 576 sdl->sdl_rcf = sdl->sdl_rcf & 0xff1f; 577 /* Set up source routing information for reply packet (XXX)*/ 578 m->m_data -= (th->rcf & 0x001f); 579 m->m_len += (th->rcf & 0x001f); 580 m->m_pkthdr.len += (th->rcf & 0x001f); 581 } else { 582 th->iso88025_shost[0] &= 0x7f; 583 } 584 m->m_data -= 8; 585 m->m_len += 8; 586 m->m_pkthdr.len += 8; 587 th->rcf = sdl->sdl_rcf; 588 589 } else { 590 sdl->sdl_rcf = NULL; 591 } 592 if (rt->rt_expire) 593 rt->rt_expire = time_second + arpt_keep; 594 rt->rt_flags &= ~RTF_REJECT; 595 la->la_asked = 0; 596 if (la->la_hold) { 597 (*ac->ac_if.if_output)(&ac->ac_if, la->la_hold, 598 rt_key(rt), rt); 599 la->la_hold = 0; 600 } 601 } 602reply: 603 if (op != ARPOP_REQUEST) { 604 m_freem(m); 605 return; 606 } 607 if (itaddr.s_addr == myaddr.s_addr) { 608 /* I am the target */ 609 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 610 (void)memcpy(ea->arp_sha, ac->ac_enaddr, sizeof(ea->arp_sha)); 611 } else { 612 la = arplookup(itaddr.s_addr, 0, SIN_PROXY); 613 if (la == NULL) { 614 struct sockaddr_in sin; 615 616 if (!arp_proxyall) { 617 m_freem(m); 618 return; 619 } 620 621 bzero(&sin, sizeof sin); 622 sin.sin_family = AF_INET; 623 sin.sin_len = sizeof sin; 624 sin.sin_addr = itaddr; 625 626 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL); 627 if (!rt) { 628 m_freem(m); 629 return; 630 } 631 /* 632 * Don't send proxies for nodes on the same interface 633 * as this one came out of, or we'll get into a fight 634 * over who claims what Ether address. 635 */ 636 if (rt->rt_ifp == &ac->ac_if) { 637 rtfree(rt); 638 m_freem(m); 639 return; 640 } 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 rtfree(rt); 644#ifdef DEBUG_PROXY 645 printf("arp: proxying for %s\n", 646 inet_ntoa(itaddr)); 647#endif 648 } else { 649 rt = la->la_rt; 650 (void)memcpy(ea->arp_tha, ea->arp_sha, sizeof(ea->arp_sha)); 651 sdl = SDL(rt->rt_gateway); 652 (void)memcpy(ea->arp_sha, LLADDR(sdl), sizeof(ea->arp_sha)); 653 } 654 } 655 656 (void)memcpy(ea->arp_tpa, ea->arp_spa, sizeof(ea->arp_spa)); 657 (void)memcpy(ea->arp_spa, &itaddr, sizeof(ea->arp_spa)); 658 ea->arp_op = htons(ARPOP_REPLY); 659 ea->arp_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 660 switch (ac->ac_if.if_type) { 661 case IFT_ISO88025: 662 /* Re-arrange the source/dest address */ 663 memcpy(th->iso88025_dhost, th->iso88025_shost, sizeof(th->iso88025_dhost)); 664 memcpy(th->iso88025_shost, ac->ac_enaddr, sizeof(th->iso88025_shost)); 665 /* Set the source routing bit if neccesary */ 666 if (th->iso88025_dhost[0] & 0x80) { 667 th->iso88025_dhost[0] &= 0x7f; 668 if ((th->rcf & 0x001f) - 2) 669 th->iso88025_shost[0] |= 0x80; 670 } 671 /* Copy the addresses, ac and fc into sa_data */ 672 memcpy(sa.sa_data, th->iso88025_dhost, sizeof(th->iso88025_dhost) * 2); 673 sa.sa_data[(sizeof(th->iso88025_dhost) * 2)] = 0x10; 674 sa.sa_data[(sizeof(th->iso88025_dhost) * 2) + 1] = 0x40; 675 break; 676 case IFT_ETHER: 677 eh = (struct ether_header *)sa.sa_data; 678 (void)memcpy(eh->ether_dhost, ea->arp_tha, sizeof(eh->ether_dhost)); 679 eh->ether_type = htons(ETHERTYPE_ARP); 680 break; 681 default: 682 m_free(m); 683 return; 684 } 685 sa.sa_family = AF_UNSPEC; 686 sa.sa_len = sizeof(sa); 687 (*ac->ac_if.if_output)(&ac->ac_if, m, &sa, (struct rtentry *)0); 688 return; 689} 690#endif 691 692/* 693 * Free an arp entry. 694 */ 695static void 696arptfree(la) 697 register struct llinfo_arp *la; 698{ 699 register struct rtentry *rt = la->la_rt; 700 register struct sockaddr_dl *sdl; 701 if (rt == 0) 702 panic("arptfree"); 703 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 704 sdl->sdl_family == AF_LINK) { 705 sdl->sdl_alen = 0; 706 la->la_asked = 0; 707 rt->rt_flags &= ~RTF_REJECT; 708 return; 709 } 710 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 711 0, (struct rtentry **)0); 712} 713/* 714 * Lookup or enter a new address in arptab. 715 */ 716static struct llinfo_arp * 717arplookup(addr, create, proxy) 718 u_long addr; 719 int create, proxy; 720{ 721 register struct rtentry *rt; 722 static struct sockaddr_inarp sin = {sizeof(sin), AF_INET }; 723 const char *why = 0; 724 725 sin.sin_addr.s_addr = addr; 726 sin.sin_other = proxy ? SIN_PROXY : 0; 727 rt = rtalloc1((struct sockaddr *)&sin, create, 0UL); 728 if (rt == 0) 729 return (0); 730 rt->rt_refcnt--; 731 732 if (rt->rt_flags & RTF_GATEWAY) 733 why = "host is not on local network"; 734 else if ((rt->rt_flags & RTF_LLINFO) == 0) 735 why = "could not allocate llinfo"; 736 else if (rt->rt_gateway->sa_family != AF_LINK) 737 why = "gateway route is not ours"; 738 739 if (why && create) { 740 log(LOG_DEBUG, "arplookup %s failed: %s\n", 741 inet_ntoa(sin.sin_addr), why); 742 return 0; 743 } else if (why) { 744 return 0; 745 } 746 return ((struct llinfo_arp *)rt->rt_llinfo); 747} 748 749void 750arp_ifinit(ac, ifa) 751 struct arpcom *ac; 752 struct ifaddr *ifa; 753{ 754 if (ntohl(IA_SIN(ifa)->sin_addr.s_addr) != INADDR_ANY) 755 arprequest(ac, &IA_SIN(ifa)->sin_addr, 756 &IA_SIN(ifa)->sin_addr, ac->ac_enaddr); 757 ifa->ifa_rtrequest = arp_rtrequest; 758 ifa->ifa_flags |= RTF_CLONING; 759} 760