1 /* 2 * Copyright (c) 1982, 1986, 1991, 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 * @(#)in.c 8.4 (Berkeley) 1/9/95 34 * $Id: in.c,v 1.33 1997/03/24 11:33:25 bde Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/queue.h> 39 #include <sys/systm.h> 40 #include <sys/sockio.h> 41 #include <sys/errno.h> 42 #include <sys/malloc.h> 43 #include <sys/proc.h> 44 #include <sys/socket.h> 45 #include <sys/socketvar.h> 46 #include <sys/kernel.h> 47 #include <sys/sysctl.h> 48 49 #include <net/if.h> 50 #include <net/route.h> 51 52 #include <netinet/in_systm.h> 53 #include <netinet/in.h> 54 #include <netinet/in_var.h> 55 #include <netinet/if_ether.h> 56 57 #include <netinet/igmp_var.h> 58 59 static void in_socktrim __P((struct sockaddr_in *)); 60 static int in_ifinit __P((struct ifnet *, 61 struct in_ifaddr *, struct sockaddr_in *, int)); 62 63 static int subnetsarelocal = 0; 64 SYSCTL_INT(_net_inet_ip, OID_AUTO, subnets_are_local, CTLFLAG_RW, 65 &subnetsarelocal, 0, ""); 66 67 struct in_multihead in_multihead; /* XXX BSS initialization */ 68 69 /* 70 * Return 1 if an internet address is for a ``local'' host 71 * (one to which we have a connection). If subnetsarelocal 72 * is true, this includes other subnets of the local net. 73 * Otherwise, it includes only the directly-connected (sub)nets. 74 */ 75 int 76 in_localaddr(in) 77 struct in_addr in; 78 { 79 register u_long i = ntohl(in.s_addr); 80 register struct in_ifaddr *ia; 81 82 if (subnetsarelocal) { 83 for (ia = in_ifaddrhead.tqh_first; ia; 84 ia = ia->ia_link.tqe_next) 85 if ((i & ia->ia_netmask) == ia->ia_net) 86 return (1); 87 } else { 88 for (ia = in_ifaddrhead.tqh_first; ia; 89 ia = ia->ia_link.tqe_next) 90 if ((i & ia->ia_subnetmask) == ia->ia_subnet) 91 return (1); 92 } 93 return (0); 94 } 95 96 /* 97 * Determine whether an IP address is in a reserved set of addresses 98 * that may not be forwarded, or whether datagrams to that destination 99 * may be forwarded. 100 */ 101 int 102 in_canforward(in) 103 struct in_addr in; 104 { 105 register u_long i = ntohl(in.s_addr); 106 register u_long net; 107 108 if (IN_EXPERIMENTAL(i) || IN_MULTICAST(i)) 109 return (0); 110 if (IN_CLASSA(i)) { 111 net = i & IN_CLASSA_NET; 112 if (net == 0 || net == (IN_LOOPBACKNET << IN_CLASSA_NSHIFT)) 113 return (0); 114 } 115 return (1); 116 } 117 118 /* 119 * Trim a mask in a sockaddr 120 */ 121 static void 122 in_socktrim(ap) 123 struct sockaddr_in *ap; 124 { 125 register char *cplim = (char *) &ap->sin_addr; 126 register char *cp = (char *) (&ap->sin_addr + 1); 127 128 ap->sin_len = 0; 129 while (--cp >= cplim) 130 if (*cp) { 131 (ap)->sin_len = cp - (char *) (ap) + 1; 132 break; 133 } 134 } 135 136 static int in_interfaces; /* number of external internet interfaces */ 137 138 /* 139 * Generic internet control operations (ioctl's). 140 * Ifp is 0 if not an interface-specific ioctl. 141 */ 142 /* ARGSUSED */ 143 int 144 in_control(so, cmd, data, ifp, p) 145 struct socket *so; 146 int cmd; 147 caddr_t data; 148 register struct ifnet *ifp; 149 struct proc *p; 150 { 151 register struct ifreq *ifr = (struct ifreq *)data; 152 register struct in_ifaddr *ia = 0, *iap; 153 register struct ifaddr *ifa; 154 struct in_ifaddr *oia; 155 struct in_aliasreq *ifra = (struct in_aliasreq *)data; 156 struct sockaddr_in oldaddr; 157 int error, hostIsNew, maskIsNew, s; 158 u_long i; 159 160 /* 161 * Find address for this interface, if it exists. 162 * 163 * If an alias address was specified, find that one instead of 164 * the first one on the interface. 165 */ 166 if (ifp) 167 for (iap = in_ifaddrhead.tqh_first; iap; 168 iap = iap->ia_link.tqe_next) 169 if (iap->ia_ifp == ifp) { 170 if (((struct sockaddr_in *)&ifr->ifr_addr)->sin_addr.s_addr == 171 iap->ia_addr.sin_addr.s_addr) { 172 ia = iap; 173 break; 174 } else if (ia == NULL) { 175 ia = iap; 176 if (ifr->ifr_addr.sa_family != AF_INET) 177 break; 178 } 179 } 180 181 switch (cmd) { 182 183 case SIOCAIFADDR: 184 case SIOCDIFADDR: 185 if (ifra->ifra_addr.sin_family == AF_INET) { 186 for (oia = ia; ia; ia = ia->ia_link.tqe_next) { 187 if (ia->ia_ifp == ifp && 188 ia->ia_addr.sin_addr.s_addr == 189 ifra->ifra_addr.sin_addr.s_addr) 190 break; 191 } 192 if ((ifp->if_flags & IFF_POINTOPOINT) 193 && (cmd == SIOCAIFADDR) 194 && (ifra->ifra_dstaddr.sin_addr.s_addr 195 == INADDR_ANY)) { 196 return EDESTADDRREQ; 197 } 198 } 199 if (cmd == SIOCDIFADDR && ia == 0) 200 return (EADDRNOTAVAIL); 201 /* FALLTHROUGH */ 202 case SIOCSIFADDR: 203 case SIOCSIFNETMASK: 204 case SIOCSIFDSTADDR: 205 if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0) 206 return error; 207 208 if (ifp == 0) 209 panic("in_control"); 210 if (ia == (struct in_ifaddr *)0) { 211 ia = (struct in_ifaddr *) 212 malloc(sizeof *ia, M_IFADDR, M_WAITOK); 213 if (ia == (struct in_ifaddr *)NULL) 214 return (ENOBUFS); 215 bzero((caddr_t)ia, sizeof *ia); 216 /* 217 * Protect from ipintr() traversing address list 218 * while we're modifying it. 219 */ 220 s = splnet(); 221 222 TAILQ_INSERT_TAIL(&in_ifaddrhead, ia, ia_link); 223 ifa = &ia->ia_ifa; 224 TAILQ_INSERT_TAIL(&ifp->if_addrhead, ifa, ifa_link); 225 226 ifa->ifa_addr = (struct sockaddr *)&ia->ia_addr; 227 ifa->ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr; 228 ifa->ifa_netmask = (struct sockaddr *)&ia->ia_sockmask; 229 ia->ia_sockmask.sin_len = 8; 230 if (ifp->if_flags & IFF_BROADCAST) { 231 ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr); 232 ia->ia_broadaddr.sin_family = AF_INET; 233 } 234 ia->ia_ifp = ifp; 235 if (!(ifp->if_flags & IFF_LOOPBACK)) 236 in_interfaces++; 237 splx(s); 238 } 239 break; 240 241 case SIOCSIFBRDADDR: 242 if (p && (error = suser(p->p_ucred, &p->p_acflag)) != 0) 243 return error; 244 /* FALLTHROUGH */ 245 246 case SIOCGIFADDR: 247 case SIOCGIFNETMASK: 248 case SIOCGIFDSTADDR: 249 case SIOCGIFBRDADDR: 250 if (ia == (struct in_ifaddr *)0) 251 return (EADDRNOTAVAIL); 252 break; 253 } 254 switch (cmd) { 255 256 case SIOCGIFADDR: 257 *((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_addr; 258 break; 259 260 case SIOCGIFBRDADDR: 261 if ((ifp->if_flags & IFF_BROADCAST) == 0) 262 return (EINVAL); 263 *((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_broadaddr; 264 break; 265 266 case SIOCGIFDSTADDR: 267 if ((ifp->if_flags & IFF_POINTOPOINT) == 0) 268 return (EINVAL); 269 *((struct sockaddr_in *)&ifr->ifr_dstaddr) = ia->ia_dstaddr; 270 break; 271 272 case SIOCGIFNETMASK: 273 *((struct sockaddr_in *)&ifr->ifr_addr) = ia->ia_sockmask; 274 break; 275 276 case SIOCSIFDSTADDR: 277 if ((ifp->if_flags & IFF_POINTOPOINT) == 0) 278 return (EINVAL); 279 oldaddr = ia->ia_dstaddr; 280 ia->ia_dstaddr = *(struct sockaddr_in *)&ifr->ifr_dstaddr; 281 if (ifp->if_ioctl && (error = (*ifp->if_ioctl) 282 (ifp, SIOCSIFDSTADDR, (caddr_t)ia))) { 283 ia->ia_dstaddr = oldaddr; 284 return (error); 285 } 286 if (ia->ia_flags & IFA_ROUTE) { 287 ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&oldaddr; 288 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST); 289 ia->ia_ifa.ifa_dstaddr = 290 (struct sockaddr *)&ia->ia_dstaddr; 291 rtinit(&(ia->ia_ifa), (int)RTM_ADD, RTF_HOST|RTF_UP); 292 } 293 break; 294 295 case SIOCSIFBRDADDR: 296 if ((ifp->if_flags & IFF_BROADCAST) == 0) 297 return (EINVAL); 298 ia->ia_broadaddr = *(struct sockaddr_in *)&ifr->ifr_broadaddr; 299 break; 300 301 case SIOCSIFADDR: 302 return (in_ifinit(ifp, ia, 303 (struct sockaddr_in *) &ifr->ifr_addr, 1)); 304 305 case SIOCSIFNETMASK: 306 i = ifra->ifra_addr.sin_addr.s_addr; 307 ia->ia_subnetmask = ntohl(ia->ia_sockmask.sin_addr.s_addr = i); 308 break; 309 310 case SIOCAIFADDR: 311 maskIsNew = 0; 312 hostIsNew = 1; 313 error = 0; 314 if (ia->ia_addr.sin_family == AF_INET) { 315 if (ifra->ifra_addr.sin_len == 0) { 316 ifra->ifra_addr = ia->ia_addr; 317 hostIsNew = 0; 318 } else if (ifra->ifra_addr.sin_addr.s_addr == 319 ia->ia_addr.sin_addr.s_addr) 320 hostIsNew = 0; 321 } 322 if (ifra->ifra_mask.sin_len) { 323 in_ifscrub(ifp, ia); 324 ia->ia_sockmask = ifra->ifra_mask; 325 ia->ia_subnetmask = 326 ntohl(ia->ia_sockmask.sin_addr.s_addr); 327 maskIsNew = 1; 328 } 329 if ((ifp->if_flags & IFF_POINTOPOINT) && 330 (ifra->ifra_dstaddr.sin_family == AF_INET)) { 331 in_ifscrub(ifp, ia); 332 ia->ia_dstaddr = ifra->ifra_dstaddr; 333 maskIsNew = 1; /* We lie; but the effect's the same */ 334 } 335 if (ifra->ifra_addr.sin_family == AF_INET && 336 (hostIsNew || maskIsNew)) 337 error = in_ifinit(ifp, ia, &ifra->ifra_addr, 0); 338 if ((ifp->if_flags & IFF_BROADCAST) && 339 (ifra->ifra_broadaddr.sin_family == AF_INET)) 340 ia->ia_broadaddr = ifra->ifra_broadaddr; 341 return (error); 342 343 case SIOCDIFADDR: 344 in_ifscrub(ifp, ia); 345 /* 346 * Protect from ipintr() traversing address list 347 * while we're modifying it. 348 */ 349 s = splnet(); 350 351 ifa = &ia->ia_ifa; 352 TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link); 353 oia = ia; 354 TAILQ_REMOVE(&in_ifaddrhead, oia, ia_link); 355 IFAFREE(&oia->ia_ifa); 356 splx(s); 357 break; 358 359 default: 360 if (ifp == 0 || ifp->if_ioctl == 0) 361 return (EOPNOTSUPP); 362 return ((*ifp->if_ioctl)(ifp, cmd, data)); 363 } 364 return (0); 365 } 366 367 /* 368 * Delete any existing route for an interface. 369 */ 370 void 371 in_ifscrub(ifp, ia) 372 register struct ifnet *ifp; 373 register struct in_ifaddr *ia; 374 { 375 376 if ((ia->ia_flags & IFA_ROUTE) == 0) 377 return; 378 if (ifp->if_flags & (IFF_LOOPBACK|IFF_POINTOPOINT)) 379 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, RTF_HOST); 380 else 381 rtinit(&(ia->ia_ifa), (int)RTM_DELETE, 0); 382 ia->ia_flags &= ~IFA_ROUTE; 383 } 384 385 /* 386 * Initialize an interface's internet address 387 * and routing table entry. 388 */ 389 static int 390 in_ifinit(ifp, ia, sin, scrub) 391 register struct ifnet *ifp; 392 register struct in_ifaddr *ia; 393 struct sockaddr_in *sin; 394 int scrub; 395 { 396 register u_long i = ntohl(sin->sin_addr.s_addr); 397 struct sockaddr_in oldaddr; 398 int s = splimp(), flags = RTF_UP, error; 399 400 oldaddr = ia->ia_addr; 401 ia->ia_addr = *sin; 402 /* 403 * Give the interface a chance to initialize 404 * if this is its first address, 405 * and to validate the address if necessary. 406 */ 407 if (ifp->if_ioctl && 408 (error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) { 409 splx(s); 410 ia->ia_addr = oldaddr; 411 return (error); 412 } 413 splx(s); 414 if (scrub) { 415 ia->ia_ifa.ifa_addr = (struct sockaddr *)&oldaddr; 416 in_ifscrub(ifp, ia); 417 ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr; 418 } 419 if (IN_CLASSA(i)) 420 ia->ia_netmask = IN_CLASSA_NET; 421 else if (IN_CLASSB(i)) 422 ia->ia_netmask = IN_CLASSB_NET; 423 else 424 ia->ia_netmask = IN_CLASSC_NET; 425 /* 426 * The subnet mask usually includes at least the standard network part, 427 * but may may be smaller in the case of supernetting. 428 * If it is set, we believe it. 429 */ 430 if (ia->ia_subnetmask == 0) { 431 ia->ia_subnetmask = ia->ia_netmask; 432 ia->ia_sockmask.sin_addr.s_addr = htonl(ia->ia_subnetmask); 433 } else 434 ia->ia_netmask &= ia->ia_subnetmask; 435 ia->ia_net = i & ia->ia_netmask; 436 ia->ia_subnet = i & ia->ia_subnetmask; 437 in_socktrim(&ia->ia_sockmask); 438 /* 439 * Add route for the network. 440 */ 441 ia->ia_ifa.ifa_metric = ifp->if_metric; 442 if (ifp->if_flags & IFF_BROADCAST) { 443 ia->ia_broadaddr.sin_addr.s_addr = 444 htonl(ia->ia_subnet | ~ia->ia_subnetmask); 445 ia->ia_netbroadcast.s_addr = 446 htonl(ia->ia_net | ~ ia->ia_netmask); 447 } else if (ifp->if_flags & IFF_LOOPBACK) { 448 ia->ia_ifa.ifa_dstaddr = ia->ia_ifa.ifa_addr; 449 flags |= RTF_HOST; 450 } else if (ifp->if_flags & IFF_POINTOPOINT) { 451 if (ia->ia_dstaddr.sin_family != AF_INET) 452 return (0); 453 flags |= RTF_HOST; 454 } 455 if ((error = rtinit(&(ia->ia_ifa), (int)RTM_ADD, flags)) == 0) 456 ia->ia_flags |= IFA_ROUTE; 457 458 /* 459 * If the interface supports multicast, join the "all hosts" 460 * multicast group on that interface. 461 */ 462 if (ifp->if_flags & IFF_MULTICAST) { 463 struct in_addr addr; 464 465 addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP); 466 in_addmulti(&addr, ifp); 467 } 468 return (error); 469 } 470 471 472 /* 473 * Return 1 if the address might be a local broadcast address. 474 */ 475 int 476 in_broadcast(in, ifp) 477 struct in_addr in; 478 struct ifnet *ifp; 479 { 480 register struct ifaddr *ifa; 481 u_long t; 482 483 if (in.s_addr == INADDR_BROADCAST || 484 in.s_addr == INADDR_ANY) 485 return 1; 486 if ((ifp->if_flags & IFF_BROADCAST) == 0) 487 return 0; 488 t = ntohl(in.s_addr); 489 /* 490 * Look through the list of addresses for a match 491 * with a broadcast address. 492 */ 493 #define ia ((struct in_ifaddr *)ifa) 494 for (ifa = ifp->if_addrhead.tqh_first; ifa; 495 ifa = ifa->ifa_link.tqe_next) 496 if (ifa->ifa_addr->sa_family == AF_INET && 497 (in.s_addr == ia->ia_broadaddr.sin_addr.s_addr || 498 in.s_addr == ia->ia_netbroadcast.s_addr || 499 /* 500 * Check for old-style (host 0) broadcast. 501 */ 502 t == ia->ia_subnet || t == ia->ia_net) && 503 /* 504 * Check for an all one subnetmask. These 505 * only exist when an interface gets a secondary 506 * address. 507 */ 508 ia->ia_subnetmask != (u_long)0xffffffff) 509 return 1; 510 return (0); 511 #undef ia 512 } 513 /* 514 * Add an address to the list of IP multicast addresses for a given interface. 515 */ 516 struct in_multi * 517 in_addmulti(ap, ifp) 518 register struct in_addr *ap; 519 register struct ifnet *ifp; 520 { 521 register struct in_multi *inm; 522 int error; 523 struct sockaddr_in sin; 524 struct ifmultiaddr *ifma; 525 int s = splnet(); 526 527 /* 528 * Call generic routine to add membership or increment 529 * refcount. It wants addresses in the form of a sockaddr, 530 * so we build one here (being careful to zero the unused bytes). 531 */ 532 bzero(&sin, sizeof sin); 533 sin.sin_family = AF_INET; 534 sin.sin_len = sizeof sin; 535 sin.sin_addr = *ap; 536 error = if_addmulti(ifp, (struct sockaddr *)&sin, &ifma); 537 if (error) { 538 splx(s); 539 return 0; 540 } 541 542 /* 543 * If ifma->ifma_protospec is null, then if_addmulti() created 544 * a new record. Otherwise, we are done. 545 */ 546 if (ifma->ifma_protospec != 0) 547 return ifma->ifma_protospec; 548 549 /* XXX - if_addmulti uses M_WAITOK. Can this really be called 550 at interrupt time? If so, need to fix if_addmulti. XXX */ 551 inm = (struct in_multi *)malloc(sizeof(*inm), M_IPMADDR, M_NOWAIT); 552 if (inm == NULL) { 553 splx(s); 554 return (NULL); 555 } 556 557 bzero(inm, sizeof *inm); 558 inm->inm_addr = *ap; 559 inm->inm_ifp = ifp; 560 inm->inm_ifma = ifma; 561 ifma->ifma_protospec = inm; 562 LIST_INSERT_HEAD(&in_multihead, inm, inm_link); 563 564 /* 565 * Let IGMP know that we have joined a new IP multicast group. 566 */ 567 igmp_joingroup(inm); 568 splx(s); 569 return (inm); 570 } 571 572 /* 573 * Delete a multicast address record. 574 */ 575 void 576 in_delmulti(inm) 577 register struct in_multi *inm; 578 { 579 struct ifmultiaddr *ifma = inm->inm_ifma; 580 int s = splnet(); 581 582 if (ifma->ifma_refcount == 1) { 583 /* 584 * No remaining claims to this record; let IGMP know that 585 * we are leaving the multicast group. 586 */ 587 igmp_leavegroup(inm); 588 ifma->ifma_protospec = 0; 589 LIST_REMOVE(inm, inm_link); 590 free(inm, M_IPMADDR); 591 } 592 /* XXX - should be separate API for when we have an ifma? */ 593 if_delmulti(ifma->ifma_ifp, ifma->ifma_addr); 594 splx(s); 595 } 596