1 /* $NetBSD: in.c,v 1.18 1995/04/13 06:27:03 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)in.c 8.2 (Berkeley) 11/15/93 36 */ 37 38 #include <sys/param.h> 39 #include <sys/ioctl.h> 40 #include <sys/errno.h> 41 #include <sys/malloc.h> 42 #include <sys/socket.h> 43 #include <sys/socketvar.h> 44 45 #include <net/if.h> 46 #include <net/route.h> 47 48 #include <netinet/in_systm.h> 49 #include <netinet/in.h> 50 #include <netinet/in_var.h> 51 #include <netinet/if_ether.h> 52 53 #include "ether.h" 54 55 #ifdef INET 56 /* 57 * Return the network number from an internet address. 58 */ 59 u_int32_t 60 in_netof(in) 61 struct in_addr in; 62 { 63 register u_int32_t i = ntohl(in.s_addr); 64 register u_int32_t net; 65 register struct in_ifaddr *ia; 66 67 if (IN_CLASSA(i)) 68 net = i & IN_CLASSA_NET; 69 else if (IN_CLASSB(i)) 70 net = i & IN_CLASSB_NET; 71 else if (IN_CLASSC(i)) 72 net = i & IN_CLASSC_NET; 73 else if (IN_CLASSD(i)) 74 net = i & IN_CLASSD_NET; 75 else 76 return (0); 77 78 /* 79 * Check whether network is a subnet; 80 * if so, return subnet number. 81 */ 82 for (ia = in_ifaddr; ia; ia = ia->ia_next) 83 if (net == ia->ia_net) 84 return (i & ia->ia_subnetmask); 85 return (net); 86 } 87 88 #ifndef SUBNETSARELOCAL 89 #define SUBNETSARELOCAL 1 90 #endif 91 int subnetsarelocal = SUBNETSARELOCAL; 92 /* 93 * Return 1 if an internet address is for a ``local'' host 94 * (one to which we have a connection). If subnetsarelocal 95 * is true, this includes other subnets of the local net. 96 * Otherwise, it includes only the directly-connected (sub)nets. 97 */ 98 int 99 in_localaddr(in) 100 struct in_addr in; 101 { 102 register u_int32_t i = ntohl(in.s_addr); 103 register struct in_ifaddr *ia; 104 105 if (subnetsarelocal) { 106 for (ia = in_ifaddr; ia; ia = ia->ia_next) 107 if ((i & ia->ia_netmask) == ia->ia_net) 108 return (1); 109 } else { 110 for (ia = in_ifaddr; ia; ia = ia->ia_next) 111 if ((i & ia->ia_subnetmask) == ia->ia_subnet) 112 return (1); 113 } 114 return (0); 115 } 116 117 /* 118 * Determine whether an IP address is in a reserved set of addresses 119 * that may not be forwarded, or whether datagrams to that destination 120 * may be forwarded. 121 */ 122 int 123 in_canforward(in) 124 struct in_addr in; 125 { 126 register u_int32_t i = ntohl(in.s_addr); 127 register u_int32_t net; 128 129 if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i)) 130 return (0); 131 if (IN_CLASSA(i)) { 132 net = i & IN_CLASSA_NET; 133 if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT)) 134 return (0); 135 } 136 return (1); 137 } 138 139 /* 140 * Trim a mask in a sockaddr 141 */ 142 void 143 in_socktrim(ap) 144 struct sockaddr_in *ap; 145 { 146 register char *cplim = (char *) &ap->sin_addr; 147 register char *cp = (char *) (&ap->sin_addr + 1); 148 149 ap->sin_len = 0; 150 while (--cp >= cplim) 151 if (*cp) { 152 (ap)->sin_len = cp - (char *) (ap) + 1; 153 break; 154 } 155 } 156 157 int in_interfaces; /* number of external internet interfaces */ 158 159 /* 160 * Generic internet control operations (ioctl's). 161 * Ifp is 0 if not an interface-specific ioctl. 162 */ 163 /* ARGSUSED */ 164 int 165 in_control(so, cmd, data, ifp) 166 struct socket *so; 167 u_long cmd; 168 caddr_t data; 169 register struct ifnet *ifp; 170 { 171 register struct ifreq *ifr = (struct ifreq *)data; 172 register struct in_ifaddr *ia = 0; 173 register struct ifaddr *ifa; 174 struct in_ifaddr *oia; 175 struct in_aliasreq *ifra = (struct in_aliasreq *)data; 176 struct sockaddr_in oldaddr; 177 int error, hostIsNew, maskIsNew; 178 u_int32_t i; 179 180 /* 181 * Find address for this interface, if it exists. 182 */ 183 if (ifp) 184 for (ia = in_ifaddr; ia; ia = ia->ia_next) 185 if (ia->ia_ifp == ifp) 186 break; 187 188 switch (cmd) { 189 190 case SIOCAIFADDR: 191 case SIOCDIFADDR: 192 if (ifra->ifra_addr.sin_family == AF_INET) 193 for (oia = ia; ia; ia = ia->ia_next) { 194 if (ia->ia_ifp == ifp && 195 ia->ia_addr.sin_addr.s_addr == 196 ifra->ifra_addr.sin_addr.s_addr) 197 break; 198 } 199 if (cmd == SIOCDIFADDR && ia == 0) 200 return (EADDRNOTAVAIL); 201 /* FALLTHROUGH */ 202 case SIOCSIFADDR: 203 case SIOCSIFNETMASK: 204 case SIOCSIFDSTADDR: 205 if ((so->so_state & SS_PRIV) == 0) 206 return (EPERM); 207 208 if (ifp == 0) 209 panic("in_control"); 210 if (ia == (struct in_ifaddr *)0) { 211 oia = (struct in_ifaddr *) 212 malloc(sizeof *oia, M_IFADDR, M_WAITOK); 213 if (oia == (struct in_ifaddr *)NULL) 214 return (ENOBUFS); 215 bzero((caddr_t)oia, sizeof *oia); 216 if (ia = in_ifaddr) { 217 for ( ; ia->ia_next; ia = ia->ia_next) 218 continue; 219 ia->ia_next = oia; 220 } else 221 in_ifaddr = oia; 222 ia = oia; 223 if (ifa = ifp->if_addrlist) { 224 for ( ; ifa->ifa_next; ifa = ifa->ifa_next) 225 continue; 226 ifa->ifa_next = (struct ifaddr *) ia; 227 } else 228 ifp->if_addrlist = (struct ifaddr *) ia; 229 ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr; 230 ia->ia_ifa.ifa_dstaddr 231 = (struct sockaddr *)&ia->ia_dstaddr; 232 ia->ia_ifa.ifa_netmask 233 = (struct sockaddr *)&ia->ia_sockmask; 234 ia->ia_sockmask.sin_len = 8; 235 if (ifp->if_flags & IFF_BROADCAST) { 236 ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr); 237 ia->ia_broadaddr.sin_family = AF_INET; 238 } 239 ia->ia_ifp = ifp; 240 if ((ifp->if_flags & IFF_LOOPBACK) == 0) 241 in_interfaces++; 242 } 243 break; 244 245 case SIOCSIFBRDADDR: 246 if ((so->so_state & SS_PRIV) == 0) 247 return (EPERM); 248 /* FALLTHROUGH */ 249 250 case SIOCGIFADDR: 251 case SIOCGIFNETMASK: 252 case SIOCGIFDSTADDR: 253 case SIOCGIFBRDADDR: 254 if (ia == (struct in_ifaddr *)0) 255 return (EADDRNOTAVAIL); 256 break; 257 } 258 switch (cmd) { 259 260 case SIOCGIFADDR: 261 *((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr; 262 break; 263 264 case SIOCGIFBRDADDR: 265 if ((ifp->if_flags & IFF_BROADCAST) == 0) 266 return (EINVAL); 267 *((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr; 268 break; 269 270 case SIOCGIFDSTADDR: 271 if ((ifp->if_flags & IFF_POINTOPOINT) == 0) 272 return (EINVAL); 273 *((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr; 274 break; 275 276 case SIOCGIFNETMASK: 277 *((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask; 278 break; 279 280 case SIOCSIFDSTADDR: 281 if ((ifp->if_flags & IFF_POINTOPOINT) == 0) 282 return (EINVAL); 283 oldaddr = ia->ia_dstaddr; 284 ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr; 285 if (ifp->if_ioctl && (error = (*ifp->if_ioctl) 286 (ifp, SIOCSIFDSTADDR, (caddr_t)ia))) { 287 ia->ia_dstaddr = oldaddr; 288 return (error); 289 } 290 if (ia->ia_flags & IFA_ROUTE) { 291 ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr; 292 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST); 293 ia->ia_ifa.ifa_dstaddr = 294 (struct sockaddr *)&ia->ia_dstaddr; 295 rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP); 296 } 297 break; 298 299 case SIOCSIFBRDADDR: 300 if ((ifp->if_flags & IFF_BROADCAST) == 0) 301 return (EINVAL); 302 ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr; 303 break; 304 305 case SIOCSIFADDR: 306 return (in_ifinit(ifp, ia, 307 (struct sockaddr_in *) &ifr->ifr_addr, 1)); 308 309 case SIOCSIFNETMASK: 310 i = ifra->ifra_addr.sin_addr.s_addr; 311 ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i); 312 break; 313 314 case SIOCAIFADDR: 315 maskIsNew = 0; 316 hostIsNew = 1; 317 error = 0; 318 if (ia->ia_addr.sin_family == AF_INET) { 319 if (ifra->ifra_addr.sin_len == 0) { 320 ifra->ifra_addr = ia->ia_addr; 321 hostIsNew = 0; 322 } else if (ifra->ifra_addr.sin_addr.s_addr == 323 ia->ia_addr.sin_addr.s_addr) 324 hostIsNew = 0; 325 } 326 if (ifra->ifra_mask.sin_len) { 327 in_ifscrub(ifp, ia); 328 ia->ia_sockmask = ifra->ifra_mask; 329 ia->ia_subnetmask = 330 ntohl(ia->ia_sockmask.sin_addr.s_addr); 331 maskIsNew = 1; 332 } 333 if ((ifp->if_flags & IFF_POINTOPOINT) && 334 (ifra->ifra_dstaddr.sin_family == AF_INET)) { 335 in_ifscrub(ifp, ia); 336 ia->ia_dstaddr = ifra->ifra_dstaddr; 337 maskIsNew = 1; /* We lie; but the effect's the same */ 338 } 339 if (ifra->ifra_addr.sin_family == AF_INET && 340 (hostIsNew || maskIsNew)) 341 error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0); 342 if ((ifp->if_flags & IFF_BROADCAST) && 343 (ifra->ifra_broadaddr.sin_family == AF_INET)) 344 ia->ia_broadaddr = ifra->ifra_broadaddr; 345 return (error); 346 347 case SIOCDIFADDR: 348 in_ifscrub(ifp, ia); 349 if ((ifa = ifp->if_addrlist) == (struct ifaddr *)ia) 350 ifp->if_addrlist = ifa->ifa_next; 351 else { 352 while (ifa->ifa_next && 353 (ifa->ifa_next != (struct ifaddr *)ia)) 354 ifa = ifa->ifa_next; 355 if (ifa->ifa_next) 356 ifa->ifa_next = ((struct ifaddr *)ia)->ifa_next; 357 else 358 printf("Couldn't unlink inifaddr from ifp\n"); 359 } 360 oia = ia; 361 if (oia == (ia = in_ifaddr)) 362 in_ifaddr = ia->ia_next; 363 else { 364 while (ia->ia_next && (ia->ia_next != oia)) 365 ia = ia->ia_next; 366 if (ia->ia_next) 367 ia->ia_next = oia->ia_next; 368 else 369 printf("Didn't unlink inifadr from list\n"); 370 } 371 IFAFREE((&oia->ia_ifa)); 372 break; 373 374 default: 375 if (ifp == 0 || ifp->if_ioctl == 0) 376 return (EOPNOTSUPP); 377 return ((*ifp->if_ioctl)(ifp, cmd, data)); 378 } 379 return (0); 380 } 381 382 /* 383 * Delete any existing route for an interface. 384 */ 385 void 386 in_ifscrub(ifp, ia) 387 register struct ifnet *ifp; 388 register struct in_ifaddr *ia; 389 { 390 391 if ((ia->ia_flags & IFA_ROUTE) == 0) 392 return; 393 if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT)) 394 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST); 395 else 396 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0); 397 ia->ia_flags &= ~IFA_ROUTE; 398 } 399 400 /* 401 * Initialize an interface's internet address 402 * and routing table entry. 403 */ 404 int 405 in_ifinit(ifp, ia, sin, scrub) 406 register struct ifnet *ifp; 407 register struct in_ifaddr *ia; 408 struct sockaddr_in *sin; 409 int scrub; 410 { 411 register u_int32_t i = ntohl(sin->sin_addr.s_addr); 412 struct sockaddr_in oldaddr; 413 int s = splimp(), flags = RTF_UP, error, ether_output(); 414 415 oldaddr = ia->ia_addr; 416 ia->ia_addr = *sin; 417 /* 418 * Give the interface a chance to initialize 419 * if this is its first address, 420 * and to validate the address if necessary. 421 */ 422 if (ifp->if_ioctl && 423 (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) { 424 splx(s); 425 ia->ia_addr = oldaddr; 426 return (error); 427 } 428 splx(s); 429 if (scrub) { 430 ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr; 431 in_ifscrub(ifp, ia); 432 ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr; 433 } 434 if (IN_CLASSA(i)) 435 ia->ia_netmask = IN_CLASSA_NET; 436 else if (IN_CLASSB(i)) 437 ia->ia_netmask = IN_CLASSB_NET; 438 else 439 ia->ia_netmask = IN_CLASSC_NET; 440 /* 441 * The subnet mask usually includes at least the standard network part, 442 * but may may be smaller in the case of supernetting. 443 * If it is set, we believe it. 444 */ 445 if (ia->ia_subnetmask == 0) { 446 ia->ia_subnetmask = ia->ia_netmask; 447 ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask); 448 } else 449 ia->ia_netmask &= ia->ia_subnetmask; 450 ia->ia_net = i & ia->ia_netmask; 451 ia->ia_subnet = i & ia->ia_subnetmask; 452 in_socktrim(&ia->ia_sockmask); 453 /* 454 * Add route for the network. 455 */ 456 ia->ia_ifa.ifa_metric = ifp->if_metric; 457 if (ifp->if_flags & IFF_BROADCAST) { 458 ia->ia_broadaddr.sin_addr.s_addr = 459 htonl(ia->ia_subnet | ~ia->ia_subnetmask); 460 ia->ia_netbroadcast.s_addr = 461 htonl(ia->ia_net | ~ ia->ia_netmask); 462 } else if (ifp->if_flags & IFF_LOOPBACK) { 463 ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr; 464 flags |= RTF_HOST; 465 } else if (ifp->if_flags & IFF_POINTOPOINT) { 466 if (ia->ia_dstaddr.sin_family != AF_INET) 467 return (0); 468 flags |= RTF_HOST; 469 } 470 if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0) 471 ia->ia_flags |= IFA_ROUTE; 472 /* 473 * If the interface supports multicast, join the "all hosts" 474 * multicast group on that interface. 475 */ 476 if (ifp->if_flags & IFF_MULTICAST) { 477 struct in_addr addr; 478 479 addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP); 480 in_addmulti(&addr, ifp); 481 } 482 return (error); 483 } 484 485 486 /* 487 * Return 1 if the address might be a local broadcast address. 488 */ 489 int 490 in_broadcast(in, ifp) 491 struct in_addr in; 492 struct ifnet *ifp; 493 { 494 register struct ifaddr *ifa; 495 u_int32_t t; 496 497 if (in.s_addr == INADDR_BROADCAST || 498 in.s_addr == INADDR_ANY) 499 return 1; 500 if ((ifp->if_flags & IFF_BROADCAST) == 0) 501 return 0; 502 t = ntohl(in.s_addr); 503 /* 504 * Look through the list of addresses for a match 505 * with a broadcast address. 506 */ 507 #define ia ((struct in_ifaddr *)ifa) 508 for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next) 509 if (ifa->ifa_addr->sa_family == AF_INET && 510 (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr || 511 in.s_addr == ia->ia_netbroadcast.s_addr || 512 /* 513 * Check for old-style (host 0) broadcast. 514 */ 515 t == ia->ia_subnet || t == ia->ia_net)) 516 return 1; 517 return (0); 518 #undef ia 519 } 520 521 /* 522 * Add an address to the list of IP multicast addresses for a given interface. 523 */ 524 struct in_multi * 525 in_addmulti(ap, ifp) 526 register struct in_addr *ap; 527 register struct ifnet *ifp; 528 { 529 register struct in_multi *inm; 530 struct ifreq ifr; 531 struct in_ifaddr *ia; 532 int s = splnet(); 533 534 /* 535 * See if address already in list. 536 */ 537 IN_LOOKUP_MULTI(*ap, ifp, inm); 538 if (inm != NULL) { 539 /* 540 * Found it; just increment the reference count. 541 */ 542 ++inm->inm_refcount; 543 } 544 else { 545 /* 546 * New address; allocate a new multicast record 547 * and link it into the interface's multicast list. 548 */ 549 inm = (struct in_multi *)malloc(sizeof(*inm), 550 M_IPMADDR, M_NOWAIT); 551 if (inm == NULL) { 552 splx(s); 553 return (NULL); 554 } 555 inm->inm_addr = *ap; 556 inm->inm_ifp = ifp; 557 inm->inm_refcount = 1; 558 IFP_TO_IA(ifp, ia); 559 if (ia == NULL) { 560 free(inm, M_IPMADDR); 561 splx(s); 562 return (NULL); 563 } 564 inm->inm_ia = ia; 565 inm->inm_next = ia->ia_multiaddrs; 566 ia->ia_multiaddrs = inm; 567 /* 568 * Ask the network driver to update its multicast reception 569 * filter appropriately for the new address. 570 */ 571 ((struct sockaddr_in *)&ifr.ifr_addr)->sin_family = AF_INET; 572 ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr = *ap; 573 if ((ifp->if_ioctl == NULL) || 574 (*ifp->if_ioctl)(ifp, SIOCADDMULTI,(caddr_t)&ifr) != 0) { 575 ia->ia_multiaddrs = inm->inm_next; 576 free(inm, M_IPMADDR); 577 splx(s); 578 return (NULL); 579 } 580 /* 581 * Let IGMP know that we have joined a new IP multicast group. 582 */ 583 igmp_joingroup(inm); 584 } 585 splx(s); 586 return (inm); 587 } 588 589 /* 590 * Delete a multicast address record. 591 */ 592 int 593 in_delmulti(inm) 594 register struct in_multi *inm; 595 { 596 register struct in_multi **p; 597 struct ifreq ifr; 598 int s = splnet(); 599 600 if (--inm->inm_refcount == 0) { 601 /* 602 * No remaining claims to this record; let IGMP know that 603 * we are leaving the multicast group. 604 */ 605 igmp_leavegroup(inm); 606 /* 607 * Unlink from list. 608 */ 609 for (p = &inm->inm_ia->ia_multiaddrs; 610 *p != inm; 611 p = &(*p)->inm_next) 612 continue; 613 *p = (*p)->inm_next; 614 /* 615 * Notify the network driver to update its multicast reception 616 * filter. 617 */ 618 ((struct sockaddr_in *)&(ifr.ifr_addr))->sin_family = AF_INET; 619 ((struct sockaddr_in *)&(ifr.ifr_addr))->sin_addr = 620 inm->inm_addr; 621 (*inm->inm_ifp->if_ioctl)(inm->inm_ifp, SIOCDELMULTI, 622 (caddr_t)&ifr); 623 free(inm, M_IPMADDR); 624 } 625 splx(s); 626 } 627 #endif 628