1 /* $NetBSD: if_arp.c,v 1.72 2001/01/26 11:40:32 is Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Public Access Networks Corporation ("Panix"). It was developed under 9 * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1988, 1993 42 * The Regents of the University of California. All rights reserved. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)if_ether.c 8.2 (Berkeley) 9/26/94 73 */ 74 75 /* 76 * Ethernet address resolution protocol. 77 * TODO: 78 * add "inuse/lock" bit (or ref. count) along with valid bit 79 */ 80 81 #include "opt_ddb.h" 82 #include "opt_inet.h" 83 84 #ifdef INET 85 86 #include <sys/param.h> 87 #include <sys/systm.h> 88 #include <sys/callout.h> 89 #include <sys/malloc.h> 90 #include <sys/mbuf.h> 91 #include <sys/socket.h> 92 #include <sys/time.h> 93 #include <sys/kernel.h> 94 #include <sys/errno.h> 95 #include <sys/ioctl.h> 96 #include <sys/syslog.h> 97 #include <sys/proc.h> 98 #include <sys/protosw.h> 99 #include <sys/domain.h> 100 101 #include <net/ethertypes.h> 102 #include <net/if.h> 103 #include <net/if_dl.h> 104 #include <net/if_token.h> 105 #include <net/if_types.h> 106 #include <net/route.h> 107 108 109 #include <netinet/in.h> 110 #include <netinet/in_systm.h> 111 #include <netinet/in_var.h> 112 #include <netinet/ip.h> 113 #include <netinet/if_inarp.h> 114 115 #include "loop.h" 116 #include "arc.h" 117 #if NARC > 0 118 #include <net/if_arc.h> 119 #endif 120 #include "fddi.h" 121 #if NFDDI > 0 122 #include <net/if_fddi.h> 123 #endif 124 #include "token.h" 125 #include "token.h" 126 127 #define SIN(s) ((struct sockaddr_in *)s) 128 #define SDL(s) ((struct sockaddr_dl *)s) 129 #define SRP(s) ((struct sockaddr_inarp *)s) 130 131 /* 132 * ARP trailer negotiation. Trailer protocol is not IP specific, 133 * but ARP request/response use IP addresses. 134 */ 135 #define ETHERTYPE_IPTRAILERS ETHERTYPE_TRAIL 136 137 /* timer values */ 138 int arpt_prune = (5*60*1); /* walk list every 5 minutes */ 139 int arpt_keep = (20*60); /* once resolved, good for 20 more minutes */ 140 int arpt_down = 20; /* once declared down, don't send for 20 secs */ 141 #define rt_expire rt_rmx.rmx_expire 142 143 static void arprequest __P((struct ifnet *, 144 struct in_addr *, struct in_addr *, u_int8_t *)); 145 static void arptfree __P((struct llinfo_arp *)); 146 static void arptimer __P((void *)); 147 static struct llinfo_arp *arplookup __P((struct in_addr *, int, int)); 148 static void in_arpinput __P((struct mbuf *)); 149 150 #if NLOOP > 0 151 extern struct ifnet loif[NLOOP]; 152 #endif 153 LIST_HEAD(, llinfo_arp) llinfo_arp; 154 struct ifqueue arpintrq = {0, 0, 0, 50}; 155 int arp_inuse, arp_allocated, arp_intimer; 156 int arp_maxtries = 5; 157 int useloopback = 1; /* use loopback interface for local traffic */ 158 int arpinit_done = 0; 159 160 struct arpstat arpstat; 161 struct callout arptimer_ch; 162 163 164 /* revarp state */ 165 static struct in_addr myip, srv_ip; 166 static int myip_initialized = 0; 167 static int revarp_in_progress = 0; 168 static struct ifnet *myip_ifp = NULL; 169 170 #ifdef DDB 171 static void db_print_sa __P((struct sockaddr *)); 172 static void db_print_ifa __P((struct ifaddr *)); 173 static void db_print_llinfo __P((caddr_t)); 174 static int db_show_radix_node __P((struct radix_node *, void *)); 175 #endif 176 177 /* 178 * this should be elsewhere. 179 */ 180 181 static char * 182 lla_snprintf __P((u_int8_t *, int)); 183 184 static char * 185 lla_snprintf(adrp, len) 186 u_int8_t *adrp; 187 int len; 188 { 189 static char buf[16*3]; 190 static const char hexdigits[] = { 191 '0','1','2','3','4','5','6','7', 192 '8','9','a','b','c','d','e','f' 193 }; 194 195 int i; 196 char *p; 197 198 p = buf; 199 200 *p++ = hexdigits[(*adrp)>>4]; 201 *p++ = hexdigits[(*adrp++)&0xf]; 202 203 for (i=1; i<len && i<16; i++) { 204 *p++ = ':'; 205 *p++ = hexdigits[(*adrp)>>4]; 206 *p++ = hexdigits[(*adrp++)&0xf]; 207 } 208 209 *p = 0; 210 return buf; 211 } 212 213 struct protosw arpsw[] = { 214 { 0, 0, 0, 0, 215 0, 0, 0, 0, 216 0, 217 0, 0, 0, arp_drain, 218 } 219 }; 220 221 222 struct domain arpdomain = 223 { PF_ARP, "arp", 0, 0, 0, 224 arpsw, &arpsw[sizeof(arpsw)/sizeof(arpsw[0])] 225 }; 226 227 /* 228 * ARP table locking. 229 * 230 * to prevent lossage vs. the arp_drain routine (which may be called at 231 * any time, including in a device driver context), we do two things: 232 * 233 * 1) manipulation of la->la_hold is done at splimp() (for all of 234 * about two instructions). 235 * 236 * 2) manipulation of the arp table's linked list is done under the 237 * protection of the ARP_LOCK; if arp_drain() or arptimer is called 238 * while the arp table is locked, we punt and try again later. 239 */ 240 241 int arp_locked; 242 243 static __inline int arp_lock_try __P((int)); 244 static __inline void arp_unlock __P((void)); 245 246 static __inline int 247 arp_lock_try(int recurse) 248 { 249 int s; 250 251 s = splimp(); 252 if (!recurse && arp_locked) { 253 splx(s); 254 return (0); 255 } 256 arp_locked++; 257 splx(s); 258 return (1); 259 } 260 261 static __inline void 262 arp_unlock() 263 { 264 int s; 265 266 s = splimp(); 267 arp_locked--; 268 splx(s); 269 } 270 271 #ifdef DIAGNOSTIC 272 #define ARP_LOCK(recurse) \ 273 do { \ 274 if (arp_lock_try(recurse) == 0) { \ 275 printf("%s:%d: arp already locked\n", __FILE__, __LINE__); \ 276 panic("arp_lock"); \ 277 } \ 278 } while (0) 279 #define ARP_LOCK_CHECK() \ 280 do { \ 281 if (arp_locked == 0) { \ 282 printf("%s:%d: arp lock not held\n", __FILE__, __LINE__); \ 283 panic("arp lock check"); \ 284 } \ 285 } while (0) 286 #else 287 #define ARP_LOCK(x) (void) arp_lock_try(x) 288 #define ARP_LOCK_CHECK() /* nothing */ 289 #endif 290 291 #define ARP_UNLOCK() arp_unlock() 292 293 /* 294 * ARP protocol drain routine. Called when memory is in short supply. 295 * Called at splimp(); 296 */ 297 298 void 299 arp_drain() 300 { 301 struct llinfo_arp *la, *nla; 302 int count = 0; 303 struct mbuf *mold; 304 305 if (arp_lock_try(0) == 0) { 306 printf("arp_drain: locked; punting\n"); 307 return; 308 } 309 310 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 311 nla = la->la_list.le_next; 312 313 mold = la->la_hold; 314 la->la_hold = 0; 315 316 if (mold) { 317 m_freem(mold); 318 count++; 319 } 320 } 321 ARP_UNLOCK(); 322 arpstat.as_dfrdropped += count; 323 } 324 325 326 /* 327 * Timeout routine. Age arp_tab entries periodically. 328 */ 329 /* ARGSUSED */ 330 static void 331 arptimer(arg) 332 void *arg; 333 { 334 int s; 335 struct llinfo_arp *la, *nla; 336 337 s = splsoftnet(); 338 339 if (arp_lock_try(0) == 0) { 340 /* get it later.. */ 341 splx(s); 342 return; 343 } 344 345 callout_reset(&arptimer_ch, arpt_prune * hz, arptimer, NULL); 346 for (la = llinfo_arp.lh_first; la != 0; la = nla) { 347 struct rtentry *rt = la->la_rt; 348 349 nla = la->la_list.le_next; 350 if (rt->rt_expire && rt->rt_expire <= time.tv_sec) 351 arptfree(la); /* timer has expired; clear */ 352 } 353 354 ARP_UNLOCK(); 355 356 splx(s); 357 } 358 359 /* 360 * Parallel to llc_rtrequest. 361 */ 362 void 363 arp_rtrequest(req, rt, info) 364 int req; 365 struct rtentry *rt; 366 struct rt_addrinfo *info; 367 { 368 struct sockaddr *gate = rt->rt_gateway; 369 struct llinfo_arp *la = (struct llinfo_arp *)rt->rt_llinfo; 370 static struct sockaddr_dl null_sdl = {sizeof(null_sdl), AF_LINK}; 371 size_t allocsize; 372 struct mbuf *mold; 373 int s; 374 375 if (!arpinit_done) { 376 arpinit_done = 1; 377 /* 378 * We generate expiration times from time.tv_sec 379 * so avoid accidently creating permanent routes. 380 */ 381 if (time.tv_sec == 0) { 382 time.tv_sec++; 383 } 384 callout_init(&arptimer_ch); 385 callout_reset(&arptimer_ch, hz, arptimer, NULL); 386 } 387 if (rt->rt_flags & RTF_GATEWAY) 388 return; 389 390 ARP_LOCK(1); /* we may already be locked here. */ 391 392 switch (req) { 393 394 case RTM_ADD: 395 /* 396 * XXX: If this is a manually added route to interface 397 * such as older version of routed or gated might provide, 398 * restore cloning bit. 399 */ 400 if ((rt->rt_flags & RTF_HOST) == 0 && 401 SIN(rt_mask(rt))->sin_addr.s_addr != 0xffffffff) 402 rt->rt_flags |= RTF_CLONING; 403 if (rt->rt_flags & RTF_CLONING) { 404 /* 405 * Case 1: This route should come from a route to iface. 406 */ 407 rt_setgate(rt, rt_key(rt), 408 (struct sockaddr *)&null_sdl); 409 gate = rt->rt_gateway; 410 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 411 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 412 /* 413 * Give this route an expiration time, even though 414 * it's a "permanent" route, so that routes cloned 415 * from it do not need their expiration time set. 416 */ 417 rt->rt_expire = time.tv_sec; 418 #if NFDDI > 0 419 if (rt->rt_ifp->if_type == IFT_FDDI 420 && (rt->rt_rmx.rmx_mtu > FDDIIPMTU 421 || (rt->rt_rmx.rmx_mtu == 0 422 && rt->rt_ifp->if_mtu > FDDIIPMTU))) { 423 rt->rt_rmx.rmx_mtu = FDDIIPMTU; 424 } 425 #endif 426 #if NARC > 0 427 if (rt->rt_ifp->if_type == IFT_ARCNET) { 428 int arcipifmtu; 429 430 if (rt->rt_ifp->if_flags & IFF_LINK0) 431 arcipifmtu = arc_ipmtu; 432 else 433 arcipifmtu = ARCMTU; 434 435 if (rt->rt_rmx.rmx_mtu > arcipifmtu || 436 (rt->rt_rmx.rmx_mtu == 0 && 437 rt->rt_ifp->if_mtu > arcipifmtu)) 438 439 rt->rt_rmx.rmx_mtu = arcipifmtu; 440 } 441 #endif 442 break; 443 } 444 /* Announce a new entry if requested. */ 445 if (rt->rt_flags & RTF_ANNOUNCE) 446 arprequest(rt->rt_ifp, 447 &SIN(rt_key(rt))->sin_addr, 448 &SIN(rt_key(rt))->sin_addr, 449 (u_char *)LLADDR(SDL(gate))); 450 /*FALLTHROUGH*/ 451 case RTM_RESOLVE: 452 if (gate->sa_family != AF_LINK || 453 gate->sa_len < sizeof(null_sdl)) { 454 log(LOG_DEBUG, "arp_rtrequest: bad gateway value\n"); 455 break; 456 } 457 SDL(gate)->sdl_type = rt->rt_ifp->if_type; 458 SDL(gate)->sdl_index = rt->rt_ifp->if_index; 459 if (la != 0) 460 break; /* This happens on a route change */ 461 /* 462 * Case 2: This route may come from cloning, or a manual route 463 * add with a LL address. 464 */ 465 switch (SDL(gate)->sdl_type) { 466 #if NTOKEN > 0 467 case IFT_ISO88025: 468 allocsize = sizeof(*la) + sizeof(struct token_rif); 469 break; 470 #endif /* NTOKEN > 0 */ 471 default: 472 allocsize = sizeof(*la); 473 } 474 R_Malloc(la, struct llinfo_arp *, allocsize); 475 rt->rt_llinfo = (caddr_t)la; 476 if (la == 0) { 477 log(LOG_DEBUG, "arp_rtrequest: malloc failed\n"); 478 break; 479 } 480 arp_inuse++, arp_allocated++; 481 Bzero(la, allocsize); 482 la->la_rt = rt; 483 rt->rt_flags |= RTF_LLINFO; 484 LIST_INSERT_HEAD(&llinfo_arp, la, la_list); 485 if (in_hosteq(SIN(rt_key(rt))->sin_addr, 486 (IA_SIN(rt->rt_ifa))->sin_addr)) { 487 /* 488 * This test used to be 489 * if (loif.if_flags & IFF_UP) 490 * It allowed local traffic to be forced through 491 * the hardware by configuring the loopback down. 492 * However, it causes problems during network 493 * configuration for boards that can't receive 494 * packets they send. It is now necessary to clear 495 * "useloopback" and remove the route to force 496 * traffic out to the hardware. 497 */ 498 rt->rt_expire = 0; 499 Bcopy(LLADDR(rt->rt_ifp->if_sadl), 500 LLADDR(SDL(gate)), 501 SDL(gate)->sdl_alen = 502 rt->rt_ifp->if_data.ifi_addrlen); 503 #if NLOOP > 0 504 if (useloopback) 505 rt->rt_ifp = &loif[0]; 506 #endif 507 } 508 break; 509 510 case RTM_DELETE: 511 if (la == 0) 512 break; 513 arp_inuse--; 514 LIST_REMOVE(la, la_list); 515 rt->rt_llinfo = 0; 516 rt->rt_flags &= ~RTF_LLINFO; 517 518 s = splimp(); 519 mold = la->la_hold; 520 la->la_hold = 0; 521 splx(s); 522 523 if (mold) 524 m_freem(mold); 525 526 Free((caddr_t)la); 527 } 528 ARP_UNLOCK(); 529 } 530 531 /* 532 * Broadcast an ARP request. Caller specifies: 533 * - arp header source ip address 534 * - arp header target ip address 535 * - arp header source ethernet address 536 */ 537 static void 538 arprequest(ifp, sip, tip, enaddr) 539 struct ifnet *ifp; 540 struct in_addr *sip, *tip; 541 u_int8_t *enaddr; 542 { 543 struct mbuf *m; 544 struct arphdr *ah; 545 struct sockaddr sa; 546 547 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 548 return; 549 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 550 2*ifp->if_data.ifi_addrlen; 551 m->m_pkthdr.len = m->m_len; 552 MH_ALIGN(m, m->m_len); 553 ah = mtod(m, struct arphdr *); 554 bzero((caddr_t)ah, m->m_len); 555 ah->ar_pro = htons(ETHERTYPE_IP); 556 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 557 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 558 ah->ar_op = htons(ARPOP_REQUEST); 559 bcopy((caddr_t)enaddr, (caddr_t)ar_sha(ah), ah->ar_hln); 560 bcopy((caddr_t)sip, (caddr_t)ar_spa(ah), ah->ar_pln); 561 bcopy((caddr_t)tip, (caddr_t)ar_tpa(ah), ah->ar_pln); 562 sa.sa_family = AF_ARP; 563 sa.sa_len = 2; 564 m->m_flags |= M_BCAST; 565 arpstat.as_sndtotal++; 566 arpstat.as_sndrequest++; 567 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 568 } 569 570 /* 571 * Resolve an IP address into an ethernet address. If success, 572 * desten is filled in. If there is no entry in arptab, 573 * set one up and broadcast a request for the IP address. 574 * Hold onto this mbuf and resend it once the address 575 * is finally resolved. A return value of 1 indicates 576 * that desten has been filled in and the packet should be sent 577 * normally; a 0 return indicates that the packet has been 578 * taken over here, either now or for later transmission. 579 */ 580 int 581 arpresolve(ifp, rt, m, dst, desten) 582 struct ifnet *ifp; 583 struct rtentry *rt; 584 struct mbuf *m; 585 struct sockaddr *dst; 586 u_char *desten; 587 { 588 struct llinfo_arp *la; 589 struct sockaddr_dl *sdl; 590 struct mbuf *mold; 591 int s; 592 593 if (rt) 594 la = (struct llinfo_arp *)rt->rt_llinfo; 595 else { 596 if ((la = arplookup(&SIN(dst)->sin_addr, 1, 0)) != NULL) 597 rt = la->la_rt; 598 } 599 if (la == 0 || rt == 0) { 600 arpstat.as_allocfail++; 601 log(LOG_DEBUG, 602 "arpresolve: can't allocate llinfo on %s for %s\n", 603 ifp->if_xname, in_fmtaddr(SIN(dst)->sin_addr)); 604 m_freem(m); 605 return (0); 606 } 607 sdl = SDL(rt->rt_gateway); 608 /* 609 * Check the address family and length is valid, the address 610 * is resolved; otherwise, try to resolve. 611 */ 612 if ((rt->rt_expire == 0 || rt->rt_expire > time.tv_sec) && 613 sdl->sdl_family == AF_LINK && sdl->sdl_alen != 0) { 614 bcopy(LLADDR(sdl), desten, 615 min(sdl->sdl_alen, ifp->if_data.ifi_addrlen)); 616 return 1; 617 } 618 /* 619 * There is an arptab entry, but no ethernet address 620 * response yet. Replace the held mbuf with this 621 * latest one. 622 */ 623 624 arpstat.as_dfrtotal++; 625 s = splimp(); 626 mold = la->la_hold; 627 la->la_hold = m; 628 splx(s); 629 630 if (mold) { 631 arpstat.as_dfrdropped++; 632 m_freem(mold); 633 } 634 635 /* 636 * Re-send the ARP request when appropriate. 637 */ 638 #ifdef DIAGNOSTIC 639 if (rt->rt_expire == 0) { 640 /* This should never happen. (Should it? -gwr) */ 641 printf("arpresolve: unresolved and rt_expire == 0\n"); 642 /* Set expiration time to now (expired). */ 643 rt->rt_expire = time.tv_sec; 644 } 645 #endif 646 if (rt->rt_expire) { 647 rt->rt_flags &= ~RTF_REJECT; 648 if (la->la_asked == 0 || rt->rt_expire != time.tv_sec) { 649 rt->rt_expire = time.tv_sec; 650 if (la->la_asked++ < arp_maxtries) 651 arprequest(ifp, 652 &SIN(rt->rt_ifa->ifa_addr)->sin_addr, 653 &SIN(dst)->sin_addr, 654 LLADDR(ifp->if_sadl)); 655 else { 656 rt->rt_flags |= RTF_REJECT; 657 rt->rt_expire += arpt_down; 658 la->la_asked = 0; 659 } 660 } 661 } 662 return (0); 663 } 664 665 /* 666 * Common length and type checks are done here, 667 * then the protocol-specific routine is called. 668 */ 669 void 670 arpintr() 671 { 672 struct mbuf *m; 673 struct arphdr *ar; 674 int s; 675 676 while (arpintrq.ifq_head) { 677 s = splimp(); 678 IF_DEQUEUE(&arpintrq, m); 679 splx(s); 680 if (m == 0 || (m->m_flags & M_PKTHDR) == 0) 681 panic("arpintr"); 682 683 arpstat.as_rcvtotal++; 684 685 if (m->m_len >= sizeof(struct arphdr) && 686 (ar = mtod(m, struct arphdr *)) && 687 /* XXX ntohs(ar->ar_hrd) == ARPHRD_ETHER && */ 688 m->m_len >= 689 sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 690 switch (ntohs(ar->ar_pro)) { 691 692 case ETHERTYPE_IP: 693 case ETHERTYPE_IPTRAILERS: 694 in_arpinput(m); 695 continue; 696 default: 697 arpstat.as_rcvbadproto++; 698 } 699 else 700 arpstat.as_rcvbadlen++; 701 m_freem(m); 702 } 703 } 704 705 /* 706 * ARP for Internet protocols on 10 Mb/s Ethernet. 707 * Algorithm is that given in RFC 826. 708 * In addition, a sanity check is performed on the sender 709 * protocol address, to catch impersonators. 710 * We no longer handle negotiations for use of trailer protocol: 711 * Formerly, ARP replied for protocol type ETHERTYPE_TRAIL sent 712 * along with IP replies if we wanted trailers sent to us, 713 * and also sent them in response to IP replies. 714 * This allowed either end to announce the desire to receive 715 * trailer packets. 716 * We no longer reply to requests for ETHERTYPE_TRAIL protocol either, 717 * but formerly didn't normally send requests. 718 */ 719 static void 720 in_arpinput(m) 721 struct mbuf *m; 722 { 723 struct arphdr *ah; 724 struct ifnet *ifp = m->m_pkthdr.rcvif; 725 struct llinfo_arp *la = 0; 726 struct rtentry *rt; 727 struct in_ifaddr *ia; 728 struct sockaddr_dl *sdl; 729 struct sockaddr sa; 730 struct in_addr isaddr, itaddr, myaddr; 731 int op; 732 struct mbuf *mold; 733 int s; 734 735 ah = mtod(m, struct arphdr *); 736 op = ntohs(ah->ar_op); 737 bcopy((caddr_t)ar_spa(ah), (caddr_t)&isaddr, sizeof (isaddr)); 738 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&itaddr, sizeof (itaddr)); 739 740 if (m->m_flags & (M_BCAST|M_MCAST)) 741 arpstat.as_rcvmcast++; 742 743 /* 744 * If the target IP address is zero, ignore the packet. 745 * This prevents the code below from tring to answer 746 * when we are using IP address zero (booting). 747 */ 748 if (in_nullhost(itaddr)) { 749 arpstat.as_rcvzerotpa++; 750 goto out; 751 } 752 753 /* 754 * If the source IP address is zero, this is most likely a 755 * confused host trying to use IP address zero. (Windoze?) 756 * XXX: Should we bother trying to reply to these? 757 */ 758 if (in_nullhost(isaddr)) { 759 arpstat.as_rcvzerospa++; 760 goto out; 761 } 762 763 /* 764 * Search for a matching interface address 765 * or any address on the interface to use 766 * as a dummy address in the rest of this function 767 */ 768 INADDR_TO_IA(itaddr, ia); 769 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 770 NEXT_IA_WITH_SAME_ADDR(ia); 771 772 if (ia == NULL) { 773 INADDR_TO_IA(isaddr, ia); 774 while ((ia != NULL) && ia->ia_ifp != m->m_pkthdr.rcvif) 775 NEXT_IA_WITH_SAME_ADDR(ia); 776 777 if (ia == NULL) { 778 IFP_TO_IA(ifp, ia); 779 if (ia == NULL) { 780 arpstat.as_rcvnoint++; 781 goto out; 782 } 783 } 784 } 785 786 myaddr = ia->ia_addr.sin_addr; 787 788 if (!bcmp((caddr_t)ar_sha(ah), LLADDR(ifp->if_sadl), 789 ifp->if_data.ifi_addrlen)) { 790 arpstat.as_rcvlocalsha++; 791 goto out; /* it's from me, ignore it. */ 792 } 793 794 if (!bcmp((caddr_t)ar_sha(ah), (caddr_t)ifp->if_broadcastaddr, 795 ifp->if_data.ifi_addrlen)) { 796 arpstat.as_rcvbcastsha++; 797 log(LOG_ERR, 798 "%s: arp: link address is broadcast for IP address %s!\n", 799 ifp->if_xname, in_fmtaddr(isaddr)); 800 goto out; 801 } 802 803 if (in_hosteq(isaddr, myaddr)) { 804 arpstat.as_rcvlocalspa++; 805 log(LOG_ERR, 806 "duplicate IP address %s sent from link address %s\n", 807 in_fmtaddr(isaddr), lla_snprintf(ar_sha(ah), ah->ar_hln)); 808 itaddr = myaddr; 809 goto reply; 810 } 811 la = arplookup(&isaddr, in_hosteq(itaddr, myaddr), 0); 812 if (la && (rt = la->la_rt) && (sdl = SDL(rt->rt_gateway))) { 813 if (sdl->sdl_alen && 814 bcmp((caddr_t)ar_sha(ah), LLADDR(sdl), sdl->sdl_alen)) { 815 if (rt->rt_flags & RTF_STATIC) { 816 arpstat.as_rcvoverperm++; 817 log(LOG_INFO, 818 "%s tried to overwrite permanent arp info" 819 " for %s\n", 820 lla_snprintf(ar_sha(ah), ah->ar_hln), 821 in_fmtaddr(isaddr)); 822 goto out; 823 } else if (rt->rt_ifp != ifp) { 824 arpstat.as_rcvoverint++; 825 log(LOG_INFO, 826 "%s on %s tried to overwrite " 827 "arp info for %s on %s\n", 828 lla_snprintf(ar_sha(ah), ah->ar_hln), 829 ifp->if_xname, in_fmtaddr(isaddr), 830 rt->rt_ifp->if_xname); 831 goto out; 832 } else { 833 arpstat.as_rcvover++; 834 log(LOG_INFO, 835 "arp info overwritten for %s by %s\n", 836 in_fmtaddr(isaddr), 837 lla_snprintf(ar_sha(ah), ah->ar_hln)); 838 } 839 } 840 /* 841 * sanity check for the address length. 842 * XXX this does not work for protocols with variable address 843 * length. -is 844 */ 845 if (sdl->sdl_alen && 846 sdl->sdl_alen != ah->ar_hln) { 847 arpstat.as_rcvlenchg++; 848 log(LOG_WARNING, 849 "arp from %s: new addr len %d, was %d", 850 in_fmtaddr(isaddr), ah->ar_hln, sdl->sdl_alen); 851 } 852 if (ifp->if_data.ifi_addrlen != ah->ar_hln) { 853 arpstat.as_rcvbadlen++; 854 log(LOG_WARNING, 855 "arp from %s: addr len: new %d, i/f %d (ignored)", 856 in_fmtaddr(isaddr), ah->ar_hln, 857 ifp->if_data.ifi_addrlen); 858 goto reply; 859 } 860 #if NTOKEN > 0 861 /* 862 * XXX uses m_data and assumes the complete answer including 863 * XXX token-ring headers is in the same buf 864 */ 865 if (ifp->if_type == IFT_ISO88025) { 866 struct token_header *trh; 867 868 trh = (struct token_header *)M_TRHSTART(m); 869 if (trh->token_shost[0] & TOKEN_RI_PRESENT) { 870 struct token_rif *rif; 871 size_t riflen; 872 873 rif = TOKEN_RIF(trh); 874 riflen = (ntohs(rif->tr_rcf) & 875 TOKEN_RCF_LEN_MASK) >> 8; 876 877 if (riflen > 2 && 878 riflen < sizeof(struct token_rif) && 879 (riflen & 1) == 0) { 880 rif->tr_rcf ^= htons(TOKEN_RCF_DIRECTION); 881 rif->tr_rcf &= htons(~TOKEN_RCF_BROADCAST_MASK); 882 bcopy(rif, TOKEN_RIF(la), riflen); 883 } 884 } 885 } 886 #endif /* NTOKEN > 0 */ 887 bcopy((caddr_t)ar_sha(ah), LLADDR(sdl), 888 sdl->sdl_alen = ah->ar_hln); 889 if (rt->rt_expire) 890 rt->rt_expire = time.tv_sec + arpt_keep; 891 rt->rt_flags &= ~RTF_REJECT; 892 la->la_asked = 0; 893 894 s = splimp(); 895 mold = la->la_hold; 896 la->la_hold = 0; 897 splx(s); 898 899 if (mold) { 900 arpstat.as_dfrsent++; 901 (*ifp->if_output)(ifp, mold, rt_key(rt), rt); 902 } 903 } 904 reply: 905 if (op != ARPOP_REQUEST) { 906 if (op == ARPOP_REPLY) 907 arpstat.as_rcvreply++; 908 out: 909 m_freem(m); 910 return; 911 } 912 arpstat.as_rcvrequest++; 913 if (in_hosteq(itaddr, myaddr)) { 914 /* I am the target */ 915 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 916 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 917 } else { 918 la = arplookup(&itaddr, 0, SIN_PROXY); 919 if (la == 0) 920 goto out; 921 rt = la->la_rt; 922 bcopy((caddr_t)ar_sha(ah), (caddr_t)ar_tha(ah), ah->ar_hln); 923 sdl = SDL(rt->rt_gateway); 924 bcopy(LLADDR(sdl), (caddr_t)ar_sha(ah), ah->ar_hln); 925 } 926 927 bcopy((caddr_t)ar_spa(ah), (caddr_t)ar_tpa(ah), ah->ar_pln); 928 bcopy((caddr_t)&itaddr, (caddr_t)ar_spa(ah), ah->ar_pln); 929 ah->ar_op = htons(ARPOP_REPLY); 930 ah->ar_pro = htons(ETHERTYPE_IP); /* let's be sure! */ 931 m->m_flags &= ~(M_BCAST|M_MCAST); /* never reply by broadcast */ 932 m->m_len = sizeof(*ah) + (2 * ah->ar_pln) + (2 * ah->ar_hln); 933 m->m_pkthdr.len = m->m_len; 934 sa.sa_family = AF_ARP; 935 sa.sa_len = 2; 936 arpstat.as_sndtotal++; 937 arpstat.as_sndreply++; 938 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 939 return; 940 } 941 942 /* 943 * Free an arp entry. 944 */ 945 static void 946 arptfree(la) 947 struct llinfo_arp *la; 948 { 949 struct rtentry *rt = la->la_rt; 950 struct sockaddr_dl *sdl; 951 952 ARP_LOCK_CHECK(); 953 954 if (rt == 0) 955 panic("arptfree"); 956 if (rt->rt_refcnt > 0 && (sdl = SDL(rt->rt_gateway)) && 957 sdl->sdl_family == AF_LINK) { 958 sdl->sdl_alen = 0; 959 la->la_asked = 0; 960 rt->rt_flags &= ~RTF_REJECT; 961 return; 962 } 963 rtrequest(RTM_DELETE, rt_key(rt), (struct sockaddr *)0, rt_mask(rt), 964 0, (struct rtentry **)0); 965 } 966 967 /* 968 * Lookup or enter a new address in arptab. 969 */ 970 static struct llinfo_arp * 971 arplookup(addr, create, proxy) 972 struct in_addr *addr; 973 int create, proxy; 974 { 975 struct rtentry *rt; 976 static struct sockaddr_inarp sin; 977 const char *why = 0; 978 979 sin.sin_len = sizeof(sin); 980 sin.sin_family = AF_INET; 981 sin.sin_addr = *addr; 982 sin.sin_other = proxy ? SIN_PROXY : 0; 983 rt = rtalloc1(sintosa(&sin), create); 984 if (rt == 0) 985 return (0); 986 rt->rt_refcnt--; 987 988 if (rt->rt_flags & RTF_GATEWAY) 989 why = "host is not on local network"; 990 else if ((rt->rt_flags & RTF_LLINFO) == 0) { 991 arpstat.as_allocfail++; 992 why = "could not allocate llinfo"; 993 } else if (rt->rt_gateway->sa_family != AF_LINK) 994 why = "gateway route is not ours"; 995 else 996 return ((struct llinfo_arp *)rt->rt_llinfo); 997 998 if (create) 999 log(LOG_DEBUG, "arplookup: unable to enter address" 1000 " for %s (%s)\n", 1001 in_fmtaddr(*addr), why); 1002 return (0); 1003 } 1004 1005 int 1006 arpioctl(cmd, data) 1007 u_long cmd; 1008 caddr_t data; 1009 { 1010 1011 return (EOPNOTSUPP); 1012 } 1013 1014 void 1015 arp_ifinit(ifp, ifa) 1016 struct ifnet *ifp; 1017 struct ifaddr *ifa; 1018 { 1019 struct in_addr *ip; 1020 1021 /* 1022 * Warn the user if another station has this IP address, 1023 * but only if the interface IP address is not zero. 1024 */ 1025 ip = &IA_SIN(ifa)->sin_addr; 1026 if (!in_nullhost(*ip)) 1027 arprequest(ifp, ip, ip, LLADDR(ifp->if_sadl)); 1028 1029 ifa->ifa_rtrequest = arp_rtrequest; 1030 ifa->ifa_flags |= RTF_CLONING; 1031 } 1032 1033 /* 1034 * Called from 10 Mb/s Ethernet interrupt handlers 1035 * when ether packet type ETHERTYPE_REVARP 1036 * is received. Common length and type checks are done here, 1037 * then the protocol-specific routine is called. 1038 */ 1039 void 1040 revarpinput(m) 1041 struct mbuf *m; 1042 { 1043 struct arphdr *ar; 1044 1045 if (m->m_len < sizeof(struct arphdr)) 1046 goto out; 1047 ar = mtod(m, struct arphdr *); 1048 #if 0 /* XXX I don't think we need this... and it will prevent other LL */ 1049 if (ntohs(ar->ar_hrd) != ARPHRD_ETHER) 1050 goto out; 1051 #endif 1052 if (m->m_len < sizeof(struct arphdr) + 2 * (ar->ar_hln + ar->ar_pln)) 1053 goto out; 1054 switch (ntohs(ar->ar_pro)) { 1055 1056 case ETHERTYPE_IP: 1057 case ETHERTYPE_IPTRAILERS: 1058 in_revarpinput(m); 1059 return; 1060 1061 default: 1062 break; 1063 } 1064 out: 1065 m_freem(m); 1066 } 1067 1068 /* 1069 * RARP for Internet protocols on 10 Mb/s Ethernet. 1070 * Algorithm is that given in RFC 903. 1071 * We are only using for bootstrap purposes to get an ip address for one of 1072 * our interfaces. Thus we support no user-interface. 1073 * 1074 * Since the contents of the RARP reply are specific to the interface that 1075 * sent the request, this code must ensure that they are properly associated. 1076 * 1077 * Note: also supports ARP via RARP packets, per the RFC. 1078 */ 1079 void 1080 in_revarpinput(m) 1081 struct mbuf *m; 1082 { 1083 struct ifnet *ifp; 1084 struct arphdr *ah; 1085 int op; 1086 1087 ah = mtod(m, struct arphdr *); 1088 op = ntohs(ah->ar_op); 1089 switch (op) { 1090 case ARPOP_REQUEST: 1091 case ARPOP_REPLY: /* per RFC */ 1092 in_arpinput(m); 1093 return; 1094 case ARPOP_REVREPLY: 1095 break; 1096 case ARPOP_REVREQUEST: /* handled by rarpd(8) */ 1097 default: 1098 goto out; 1099 } 1100 if (!revarp_in_progress) 1101 goto out; 1102 ifp = m->m_pkthdr.rcvif; 1103 if (ifp != myip_ifp) /* !same interface */ 1104 goto out; 1105 if (myip_initialized) 1106 goto wake; 1107 if (bcmp(ar_tha(ah), LLADDR(ifp->if_sadl), ifp->if_sadl->sdl_alen)) 1108 goto out; 1109 bcopy((caddr_t)ar_spa(ah), (caddr_t)&srv_ip, sizeof(srv_ip)); 1110 bcopy((caddr_t)ar_tpa(ah), (caddr_t)&myip, sizeof(myip)); 1111 myip_initialized = 1; 1112 wake: /* Do wakeup every time in case it was missed. */ 1113 wakeup((caddr_t)&myip); 1114 1115 out: 1116 m_freem(m); 1117 } 1118 1119 /* 1120 * Send a RARP request for the ip address of the specified interface. 1121 * The request should be RFC 903-compliant. 1122 */ 1123 void 1124 revarprequest(ifp) 1125 struct ifnet *ifp; 1126 { 1127 struct sockaddr sa; 1128 struct mbuf *m; 1129 struct arphdr *ah; 1130 1131 if ((m = m_gethdr(M_DONTWAIT, MT_DATA)) == NULL) 1132 return; 1133 m->m_len = sizeof(*ah) + 2*sizeof(struct in_addr) + 1134 2*ifp->if_data.ifi_addrlen; 1135 m->m_pkthdr.len = m->m_len; 1136 MH_ALIGN(m, m->m_len); 1137 ah = mtod(m, struct arphdr *); 1138 bzero((caddr_t)ah, m->m_len); 1139 ah->ar_pro = htons(ETHERTYPE_IP); 1140 ah->ar_hln = ifp->if_data.ifi_addrlen; /* hardware address length */ 1141 ah->ar_pln = sizeof(struct in_addr); /* protocol address length */ 1142 ah->ar_op = htons(ARPOP_REVREQUEST); 1143 1144 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_sha(ah), ah->ar_hln); 1145 bcopy(LLADDR(ifp->if_sadl), (caddr_t)ar_tha(ah), ah->ar_hln); 1146 1147 sa.sa_family = AF_ARP; 1148 sa.sa_len = 2; 1149 m->m_flags |= M_BCAST; 1150 (*ifp->if_output)(ifp, m, &sa, (struct rtentry *)0); 1151 1152 } 1153 1154 /* 1155 * RARP for the ip address of the specified interface, but also 1156 * save the ip address of the server that sent the answer. 1157 * Timeout if no response is received. 1158 */ 1159 int 1160 revarpwhoarewe(ifp, serv_in, clnt_in) 1161 struct ifnet *ifp; 1162 struct in_addr *serv_in; 1163 struct in_addr *clnt_in; 1164 { 1165 int result, count = 20; 1166 1167 myip_initialized = 0; 1168 myip_ifp = ifp; 1169 1170 revarp_in_progress = 1; 1171 while (count--) { 1172 revarprequest(ifp); 1173 result = tsleep((caddr_t)&myip, PSOCK, "revarp", hz/2); 1174 if (result != EWOULDBLOCK) 1175 break; 1176 } 1177 revarp_in_progress = 0; 1178 1179 if (!myip_initialized) 1180 return ENETUNREACH; 1181 1182 bcopy((caddr_t)&srv_ip, serv_in, sizeof(*serv_in)); 1183 bcopy((caddr_t)&myip, clnt_in, sizeof(*clnt_in)); 1184 return 0; 1185 } 1186 1187 1188 1189 #ifdef DDB 1190 1191 #include <machine/db_machdep.h> 1192 #include <ddb/db_interface.h> 1193 #include <ddb/db_output.h> 1194 static void 1195 db_print_sa(sa) 1196 struct sockaddr *sa; 1197 { 1198 int len; 1199 u_char *p; 1200 1201 if (sa == 0) { 1202 db_printf("[NULL]"); 1203 return; 1204 } 1205 1206 p = (u_char*)sa; 1207 len = sa->sa_len; 1208 db_printf("["); 1209 while (len > 0) { 1210 db_printf("%d", *p); 1211 p++; len--; 1212 if (len) db_printf(","); 1213 } 1214 db_printf("]\n"); 1215 } 1216 static void 1217 db_print_ifa(ifa) 1218 struct ifaddr *ifa; 1219 { 1220 if (ifa == 0) 1221 return; 1222 db_printf(" ifa_addr="); 1223 db_print_sa(ifa->ifa_addr); 1224 db_printf(" ifa_dsta="); 1225 db_print_sa(ifa->ifa_dstaddr); 1226 db_printf(" ifa_mask="); 1227 db_print_sa(ifa->ifa_netmask); 1228 db_printf(" flags=0x%x,refcnt=%d,metric=%d\n", 1229 ifa->ifa_flags, 1230 ifa->ifa_refcnt, 1231 ifa->ifa_metric); 1232 } 1233 static void 1234 db_print_llinfo(li) 1235 caddr_t li; 1236 { 1237 struct llinfo_arp *la; 1238 1239 if (li == 0) 1240 return; 1241 la = (struct llinfo_arp *)li; 1242 db_printf(" la_rt=%p la_hold=%p, la_asked=0x%lx\n", 1243 la->la_rt, la->la_hold, la->la_asked); 1244 } 1245 /* 1246 * Function to pass to rn_walktree(). 1247 * Return non-zero error to abort walk. 1248 */ 1249 static int 1250 db_show_radix_node(rn, w) 1251 struct radix_node *rn; 1252 void *w; 1253 { 1254 struct rtentry *rt = (struct rtentry *)rn; 1255 1256 db_printf("rtentry=%p", rt); 1257 1258 db_printf(" flags=0x%x refcnt=%d use=%ld expire=%ld\n", 1259 rt->rt_flags, rt->rt_refcnt, 1260 rt->rt_use, rt->rt_expire); 1261 1262 db_printf(" key="); db_print_sa(rt_key(rt)); 1263 db_printf(" mask="); db_print_sa(rt_mask(rt)); 1264 db_printf(" gw="); db_print_sa(rt->rt_gateway); 1265 1266 db_printf(" ifp=%p ", rt->rt_ifp); 1267 if (rt->rt_ifp) 1268 db_printf("(%s)", rt->rt_ifp->if_xname); 1269 else 1270 db_printf("(NULL)"); 1271 1272 db_printf(" ifa=%p\n", rt->rt_ifa); 1273 db_print_ifa(rt->rt_ifa); 1274 1275 db_printf(" genmask="); db_print_sa(rt->rt_genmask); 1276 1277 db_printf(" gwroute=%p llinfo=%p\n", 1278 rt->rt_gwroute, rt->rt_llinfo); 1279 db_print_llinfo(rt->rt_llinfo); 1280 1281 return (0); 1282 } 1283 /* 1284 * Function to print all the route trees. 1285 * Use this from ddb: "show arptab" 1286 */ 1287 void 1288 db_show_arptab(addr, have_addr, count, modif) 1289 db_expr_t addr; 1290 int have_addr; 1291 db_expr_t count; 1292 char * modif; 1293 { 1294 struct radix_node_head *rnh; 1295 rnh = rt_tables[AF_INET]; 1296 db_printf("Route tree for AF_INET\n"); 1297 if (rnh == NULL) { 1298 db_printf(" (not initialized)\n"); 1299 return; 1300 } 1301 rn_walktree(rnh, db_show_radix_node, NULL); 1302 return; 1303 } 1304 #endif 1305 #endif /* INET */ 1306 1307