Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/net/if_tun.c
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1 /* $NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $ */ 2 3 /* 4 * Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk> 5 * Nottingham University 1987. 6 * 7 * This source may be freely distributed, however I would be interested 8 * in any changes that are made. 9 * 10 * This driver takes packets off the IP i/f and hands them up to a 11 * user process to have its wicked way with. This driver has it's 12 * roots in a similar driver written by Phil Cockcroft (formerly) at 13 * UCL. This driver is based much more on read/write/poll mode of 14 * operation though. 15 * 16 * $FreeBSD: releng/5.0/sys/net/if_tun.c 106939 2002-11-15 00:00:15Z sam $ 17 */ 18 19 #include "opt_inet.h" 20 #include "opt_mac.h" 21 22 #include <sys/param.h> 23 #include <sys/proc.h> 24 #include <sys/systm.h> 25 #include <sys/mac.h> 26 #include <sys/mbuf.h> 27 #include <sys/module.h> 28 #include <sys/socket.h> 29 #include <sys/filio.h> 30 #include <sys/sockio.h> 31 #include <sys/ttycom.h> 32 #include <sys/poll.h> 33 #include <sys/signalvar.h> 34 #include <sys/filedesc.h> 35 #include <sys/kernel.h> 36 #include <sys/sysctl.h> 37 #include <sys/conf.h> 38 #include <sys/uio.h> 39 #include <sys/vnode.h> 40 #include <sys/malloc.h> 41 #include <machine/bus.h> /* XXX Shouldn't really be required ! */ 42 #include <sys/rman.h> 43 44 #include <net/if.h> 45 #include <net/if_types.h> 46 #include <net/route.h> 47 #include <net/intrq.h> 48 #ifdef INET 49 #include <netinet/in.h> 50 #endif 51 #include <net/bpf.h> 52 #include <net/if_tunvar.h> 53 #include <net/if_tun.h> 54 55 #define TUNDEBUG if (tundebug) printf 56 #define TUNNAME "tun" 57 #define TUN_MAXUNIT 0x7fff /* ifp->if_unit is only 15 bits */ 58 59 static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface"); 60 static int tundebug = 0; 61 static struct tun_softc *tunhead = NULL; 62 static struct rman tununits; 63 static udev_t tunbasedev = NOUDEV; 64 SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); 65 66 static void tunclone(void *arg, char *name, int namelen, dev_t *dev); 67 static void tuncreate(dev_t dev); 68 static int tunifioctl(struct ifnet *, u_long, caddr_t); 69 static int tuninit(struct ifnet *); 70 static int tunmodevent(module_t, int, void *); 71 static int tunoutput(struct ifnet *, struct mbuf *, struct sockaddr *, 72 struct rtentry *rt); 73 static void tunstart(struct ifnet *); 74 75 static d_open_t tunopen; 76 static d_close_t tunclose; 77 static d_read_t tunread; 78 static d_write_t tunwrite; 79 static d_ioctl_t tunioctl; 80 static d_poll_t tunpoll; 81 82 #define CDEV_MAJOR 52 83 static struct cdevsw tun_cdevsw = { 84 /* open */ tunopen, 85 /* close */ tunclose, 86 /* read */ tunread, 87 /* write */ tunwrite, 88 /* ioctl */ tunioctl, 89 /* poll */ tunpoll, 90 /* mmap */ nommap, 91 /* strategy */ nostrategy, 92 /* name */ TUNNAME, 93 /* maj */ CDEV_MAJOR, 94 /* dump */ nodump, 95 /* psize */ nopsize, 96 /* flags */ 0, 97 }; 98 99 static void 100 tunclone(void *arg, char *name, int namelen, dev_t *dev) 101 { 102 struct resource *r; 103 int err; 104 int u; 105 106 if (*dev != NODEV) 107 return; 108 109 if (strcmp(name, TUNNAME) == 0) { 110 r = rman_reserve_resource(&tununits, 0, TUN_MAXUNIT, 1, 111 RF_ALLOCATED | RF_ACTIVE, NULL); 112 u = rman_get_start(r); 113 err = rman_release_resource(r); 114 KASSERT(err == 0, ("Unexpected failure releasing resource")); 115 *dev = makedev(CDEV_MAJOR, unit2minor(u)); 116 if ((*dev)->si_flags & SI_NAMED) 117 return; /* Already make_dev()d */ 118 } else if (dev_stdclone(name, NULL, TUNNAME, &u) != 1) 119 return; /* Don't recognise the name */ 120 121 *dev = make_dev(&tun_cdevsw, unit2minor(u), 122 UID_ROOT, GID_WHEEL, 0600, "tun%d", u); 123 124 /* 125 * All devices depend on tunbasedev so that we can simply 126 * destroy_dev() this device at module unload time to get 127 * rid of all our make_dev()d resources. 128 */ 129 if (tunbasedev == NOUDEV) 130 tunbasedev = (*dev)->si_udev; 131 else { 132 (*dev)->si_flags |= SI_CHEAPCLONE; 133 dev_depends(udev2dev(tunbasedev, 0), *dev); 134 } 135 } 136 137 static int 138 tunmodevent(module_t mod, int type, void *data) 139 { 140 static eventhandler_tag tag; 141 struct tun_softc *tp; 142 dev_t dev; 143 int err; 144 145 switch (type) { 146 case MOD_LOAD: 147 tag = EVENTHANDLER_REGISTER(dev_clone, tunclone, 0, 1000); 148 if (tag == NULL) 149 return (ENOMEM); 150 if (!devfs_present) { 151 err = cdevsw_add(&tun_cdevsw); 152 if (err != 0) { 153 EVENTHANDLER_DEREGISTER(dev_clone, tag); 154 return (err); 155 } 156 } 157 tununits.rm_type = RMAN_ARRAY; 158 tununits.rm_descr = "open if_tun units"; 159 err = rman_init(&tununits); 160 if (err != 0) { 161 cdevsw_remove(&tun_cdevsw); 162 EVENTHANDLER_DEREGISTER(dev_clone, tag); 163 return (err); 164 } 165 err = rman_manage_region(&tununits, 0, TUN_MAXUNIT); 166 if (err != 0) { 167 printf("%s: tununits: rman_manage_region: Failed %d\n", 168 TUNNAME, err); 169 rman_fini(&tununits); 170 cdevsw_remove(&tun_cdevsw); 171 EVENTHANDLER_DEREGISTER(dev_clone, tag); 172 return (err); 173 } 174 break; 175 case MOD_UNLOAD: 176 err = rman_fini(&tununits); 177 if (err != 0) 178 return (err); 179 EVENTHANDLER_DEREGISTER(dev_clone, tag); 180 181 while (tunhead != NULL) { 182 KASSERT((tunhead->tun_flags & TUN_OPEN) == 0, 183 ("tununits is out of sync - unit %d", 184 tunhead->tun_if.if_unit)); 185 tp = tunhead; 186 dev = makedev(tun_cdevsw.d_maj, 187 unit2minor(tp->tun_if.if_unit)); 188 KASSERT(dev->si_drv1 == tp, ("Bad makedev result")); 189 tunhead = tp->next; 190 bpfdetach(&tp->tun_if); 191 if_detach(&tp->tun_if); 192 KASSERT(dev->si_flags & SI_NAMED, ("Missing make_dev")); 193 free(tp, M_TUN); 194 } 195 196 /* 197 * Destroying tunbasedev results in all of our make_dev()s 198 * conveniently going away. 199 */ 200 if (tunbasedev != NOUDEV) 201 destroy_dev(udev2dev(tunbasedev, 0)); 202 203 if (!devfs_present) 204 cdevsw_remove(&tun_cdevsw); 205 break; 206 } 207 return 0; 208 } 209 210 static moduledata_t tun_mod = { 211 "if_tun", 212 tunmodevent, 213 0 214 }; 215 216 DECLARE_MODULE(if_tun, tun_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 217 218 static void 219 tunstart(struct ifnet *ifp) 220 { 221 struct tun_softc *tp = ifp->if_softc; 222 223 if (tp->tun_flags & TUN_RWAIT) { 224 tp->tun_flags &= ~TUN_RWAIT; 225 wakeup((caddr_t)tp); 226 } 227 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) 228 pgsigio(&tp->tun_sigio, SIGIO, 0); 229 selwakeup(&tp->tun_rsel); 230 } 231 232 static void 233 tuncreate(dev_t dev) 234 { 235 struct tun_softc *sc; 236 struct ifnet *ifp; 237 238 if (!(dev->si_flags & SI_NAMED)) 239 dev = make_dev(&tun_cdevsw, minor(dev), 240 UID_UUCP, GID_DIALER, 0600, "tun%d", dev2unit(dev)); 241 242 MALLOC(sc, struct tun_softc *, sizeof(*sc), M_TUN, M_WAITOK | M_ZERO); 243 sc->tun_flags = TUN_INITED; 244 sc->next = tunhead; 245 tunhead = sc; 246 247 ifp = &sc->tun_if; 248 ifp->if_unit = dev2unit(dev); 249 ifp->if_name = TUNNAME; 250 ifp->if_mtu = TUNMTU; 251 ifp->if_ioctl = tunifioctl; 252 ifp->if_output = tunoutput; 253 ifp->if_start = tunstart; 254 ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST; 255 ifp->if_type = IFT_PPP; 256 ifp->if_snd.ifq_maxlen = ifqmaxlen; 257 ifp->if_softc = sc; 258 if_attach(ifp); 259 bpfattach(ifp, DLT_NULL, sizeof(u_int)); 260 dev->si_drv1 = sc; 261 } 262 263 static int 264 tunopen(dev_t dev, int flag, int mode, struct thread *td) 265 { 266 struct resource *r; 267 struct ifnet *ifp; 268 struct tun_softc *tp; 269 int unit; 270 271 unit = dev2unit(dev); 272 if (unit > TUN_MAXUNIT) 273 return (ENXIO); 274 275 r = rman_reserve_resource(&tununits, unit, unit, 1, 276 RF_ALLOCATED | RF_ACTIVE, NULL); 277 if (r == NULL) 278 return (EBUSY); 279 280 dev->si_flags &= ~SI_CHEAPCLONE; 281 282 tp = dev->si_drv1; 283 if (!tp) { 284 tuncreate(dev); 285 tp = dev->si_drv1; 286 } 287 KASSERT(!(tp->tun_flags & TUN_OPEN), ("Resource & flags out-of-sync")); 288 tp->r_unit = r; 289 tp->tun_pid = td->td_proc->p_pid; 290 ifp = &tp->tun_if; 291 tp->tun_flags |= TUN_OPEN; 292 TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit); 293 294 return (0); 295 } 296 297 /* 298 * tunclose - close the device - mark i/f down & delete 299 * routing info 300 */ 301 static int 302 tunclose(dev_t dev, int foo, int bar, struct thread *td) 303 { 304 struct tun_softc *tp; 305 struct ifnet *ifp; 306 int s; 307 int err; 308 309 tp = dev->si_drv1; 310 ifp = &tp->tun_if; 311 312 KASSERT(tp->r_unit, ("Unit %d not marked open", ifp->if_unit)); 313 tp->tun_flags &= ~TUN_OPEN; 314 tp->tun_pid = 0; 315 316 /* 317 * junk all pending output 318 */ 319 IF_DRAIN(&ifp->if_snd); 320 321 if (ifp->if_flags & IFF_UP) { 322 s = splimp(); 323 if_down(ifp); 324 splx(s); 325 } 326 327 if (ifp->if_flags & IFF_RUNNING) { 328 register struct ifaddr *ifa; 329 330 s = splimp(); 331 /* find internet addresses and delete routes */ 332 TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) 333 if (ifa->ifa_addr->sa_family == AF_INET) 334 rtinit(ifa, (int)RTM_DELETE, 335 tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0); 336 ifp->if_flags &= ~IFF_RUNNING; 337 splx(s); 338 } 339 340 funsetown(&tp->tun_sigio); 341 selwakeup(&tp->tun_rsel); 342 343 TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); 344 err = rman_release_resource(tp->r_unit); 345 KASSERT(err == 0, ("Unit %d failed to release", ifp->if_unit)); 346 347 return (0); 348 } 349 350 static int 351 tuninit(struct ifnet *ifp) 352 { 353 struct tun_softc *tp = ifp->if_softc; 354 register struct ifaddr *ifa; 355 int error = 0; 356 357 TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit); 358 359 ifp->if_flags |= IFF_UP | IFF_RUNNING; 360 getmicrotime(&ifp->if_lastchange); 361 362 for (ifa = TAILQ_FIRST(&ifp->if_addrhead); ifa; 363 ifa = TAILQ_NEXT(ifa, ifa_link)) { 364 if (ifa->ifa_addr == NULL) 365 error = EFAULT; 366 /* XXX: Should maybe return straight off? */ 367 else { 368 #ifdef INET 369 if (ifa->ifa_addr->sa_family == AF_INET) { 370 struct sockaddr_in *si; 371 372 si = (struct sockaddr_in *)ifa->ifa_addr; 373 if (si->sin_addr.s_addr) 374 tp->tun_flags |= TUN_IASET; 375 376 si = (struct sockaddr_in *)ifa->ifa_dstaddr; 377 if (si && si->sin_addr.s_addr) 378 tp->tun_flags |= TUN_DSTADDR; 379 } 380 #endif 381 } 382 } 383 return (error); 384 } 385 386 /* 387 * Process an ioctl request. 388 */ 389 static int 390 tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data) 391 { 392 struct ifreq *ifr = (struct ifreq *)data; 393 struct tun_softc *tp = ifp->if_softc; 394 struct ifstat *ifs; 395 int error = 0, s; 396 397 s = splimp(); 398 switch(cmd) { 399 case SIOCGIFSTATUS: 400 ifs = (struct ifstat *)data; 401 if (tp->tun_pid) 402 sprintf(ifs->ascii + strlen(ifs->ascii), 403 "\tOpened by PID %d\n", tp->tun_pid); 404 break; 405 case SIOCSIFADDR: 406 error = tuninit(ifp); 407 TUNDEBUG("%s%d: address set, error=%d\n", 408 ifp->if_name, ifp->if_unit, error); 409 break; 410 case SIOCSIFDSTADDR: 411 error = tuninit(ifp); 412 TUNDEBUG("%s%d: destination address set, error=%d\n", 413 ifp->if_name, ifp->if_unit, error); 414 break; 415 case SIOCSIFMTU: 416 ifp->if_mtu = ifr->ifr_mtu; 417 TUNDEBUG("%s%d: mtu set\n", ifp->if_name, ifp->if_unit); 418 break; 419 case SIOCSIFFLAGS: 420 case SIOCADDMULTI: 421 case SIOCDELMULTI: 422 break; 423 default: 424 error = EINVAL; 425 } 426 splx(s); 427 return (error); 428 } 429 430 /* 431 * tunoutput - queue packets from higher level ready to put out. 432 */ 433 static int 434 tunoutput( 435 struct ifnet *ifp, 436 struct mbuf *m0, 437 struct sockaddr *dst, 438 struct rtentry *rt) 439 { 440 struct tun_softc *tp = ifp->if_softc; 441 #ifdef MAC 442 int error; 443 #endif 444 445 TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit); 446 447 #ifdef MAC 448 error = mac_check_ifnet_transmit(ifp, m0); 449 if (error) { 450 m_freem(m0); 451 return (error); 452 } 453 #endif 454 455 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 456 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 457 ifp->if_unit, tp->tun_flags); 458 m_freem (m0); 459 return (EHOSTDOWN); 460 } 461 462 if ((ifp->if_flags & IFF_UP) != IFF_UP) { 463 m_freem (m0); 464 return (EHOSTDOWN); 465 } 466 467 /* BPF write needs to be handled specially */ 468 if (dst->sa_family == AF_UNSPEC) { 469 dst->sa_family = *(mtod(m0, int *)); 470 m0->m_len -= sizeof(int); 471 m0->m_pkthdr.len -= sizeof(int); 472 m0->m_data += sizeof(int); 473 } 474 475 if (ifp->if_bpf) { 476 /* 477 * We need to prepend the address family as 478 * a four byte field. Cons up a dummy header 479 * to pacify bpf. This is safe because bpf 480 * will only read from the mbuf (i.e., it won't 481 * try to free it or keep a pointer to it). 482 */ 483 struct mbuf m; 484 uint32_t af = dst->sa_family; 485 486 m.m_next = m0; 487 m.m_len = 4; 488 m.m_data = (char *)⁡ 489 490 BPF_MTAP(ifp, &m); 491 } 492 493 /* prepend sockaddr? this may abort if the mbuf allocation fails */ 494 if (tp->tun_flags & TUN_LMODE) { 495 /* allocate space for sockaddr */ 496 M_PREPEND(m0, dst->sa_len, M_DONTWAIT); 497 498 /* if allocation failed drop packet */ 499 if (m0 == NULL) { 500 ifp->if_iqdrops++; 501 ifp->if_oerrors++; 502 return (ENOBUFS); 503 } else { 504 bcopy(dst, m0->m_data, dst->sa_len); 505 } 506 } 507 508 if (tp->tun_flags & TUN_IFHEAD) { 509 /* Prepend the address family */ 510 M_PREPEND(m0, 4, M_DONTWAIT); 511 512 /* if allocation failed drop packet */ 513 if (m0 == NULL) { 514 ifp->if_iqdrops++; 515 ifp->if_oerrors++; 516 return (ENOBUFS); 517 } else 518 *(u_int32_t *)m0->m_data = htonl(dst->sa_family); 519 } else { 520 #ifdef INET 521 if (dst->sa_family != AF_INET) 522 #endif 523 { 524 m_freem(m0); 525 return (EAFNOSUPPORT); 526 } 527 } 528 529 if (! IF_HANDOFF(&ifp->if_snd, m0, ifp)) { 530 ifp->if_collisions++; 531 return (ENOBUFS); 532 } 533 ifp->if_opackets++; 534 return (0); 535 } 536 537 /* 538 * the cdevsw interface is now pretty minimal. 539 */ 540 static int 541 tunioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td) 542 { 543 int s; 544 int error; 545 struct tun_softc *tp = dev->si_drv1; 546 struct tuninfo *tunp; 547 548 switch (cmd) { 549 case TUNSIFINFO: 550 tunp = (struct tuninfo *)data; 551 if (tunp->mtu < IF_MINMTU) 552 return (EINVAL); 553 if (tp->tun_if.if_mtu != tunp->mtu 554 && (error = suser(td)) != 0) 555 return (error); 556 tp->tun_if.if_mtu = tunp->mtu; 557 tp->tun_if.if_type = tunp->type; 558 tp->tun_if.if_baudrate = tunp->baudrate; 559 break; 560 case TUNGIFINFO: 561 tunp = (struct tuninfo *)data; 562 tunp->mtu = tp->tun_if.if_mtu; 563 tunp->type = tp->tun_if.if_type; 564 tunp->baudrate = tp->tun_if.if_baudrate; 565 break; 566 case TUNSDEBUG: 567 tundebug = *(int *)data; 568 break; 569 case TUNGDEBUG: 570 *(int *)data = tundebug; 571 break; 572 case TUNSLMODE: 573 if (*(int *)data) { 574 tp->tun_flags |= TUN_LMODE; 575 tp->tun_flags &= ~TUN_IFHEAD; 576 } else 577 tp->tun_flags &= ~TUN_LMODE; 578 break; 579 case TUNSIFHEAD: 580 if (*(int *)data) { 581 tp->tun_flags |= TUN_IFHEAD; 582 tp->tun_flags &= ~TUN_LMODE; 583 } else 584 tp->tun_flags &= ~TUN_IFHEAD; 585 break; 586 case TUNGIFHEAD: 587 *(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0; 588 break; 589 case TUNSIFMODE: 590 /* deny this if UP */ 591 if (tp->tun_if.if_flags & IFF_UP) 592 return(EBUSY); 593 594 switch (*(int *)data & ~IFF_MULTICAST) { 595 case IFF_POINTOPOINT: 596 case IFF_BROADCAST: 597 tp->tun_if.if_flags &= 598 ~(IFF_BROADCAST|IFF_POINTOPOINT|IFF_MULTICAST); 599 tp->tun_if.if_flags |= *(int *)data; 600 break; 601 default: 602 return(EINVAL); 603 } 604 break; 605 case TUNSIFPID: 606 tp->tun_pid = curthread->td_proc->p_pid; 607 break; 608 case FIONBIO: 609 break; 610 case FIOASYNC: 611 if (*(int *)data) 612 tp->tun_flags |= TUN_ASYNC; 613 else 614 tp->tun_flags &= ~TUN_ASYNC; 615 break; 616 case FIONREAD: 617 s = splimp(); 618 if (tp->tun_if.if_snd.ifq_head) { 619 struct mbuf *mb = tp->tun_if.if_snd.ifq_head; 620 for( *(int *)data = 0; mb != 0; mb = mb->m_next) 621 *(int *)data += mb->m_len; 622 } else 623 *(int *)data = 0; 624 splx(s); 625 break; 626 case FIOSETOWN: 627 return (fsetown(*(int *)data, &tp->tun_sigio)); 628 629 case FIOGETOWN: 630 *(int *)data = fgetown(&tp->tun_sigio); 631 return (0); 632 633 /* This is deprecated, FIOSETOWN should be used instead. */ 634 case TIOCSPGRP: 635 return (fsetown(-(*(int *)data), &tp->tun_sigio)); 636 637 /* This is deprecated, FIOGETOWN should be used instead. */ 638 case TIOCGPGRP: 639 *(int *)data = -fgetown(&tp->tun_sigio); 640 return (0); 641 642 default: 643 return (ENOTTY); 644 } 645 return (0); 646 } 647 648 /* 649 * The cdevsw read interface - reads a packet at a time, or at 650 * least as much of a packet as can be read. 651 */ 652 static int 653 tunread(dev_t dev, struct uio *uio, int flag) 654 { 655 struct tun_softc *tp = dev->si_drv1; 656 struct ifnet *ifp = &tp->tun_if; 657 struct mbuf *m; 658 int error=0, len, s; 659 660 TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); 661 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 662 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 663 ifp->if_unit, tp->tun_flags); 664 return (EHOSTDOWN); 665 } 666 667 tp->tun_flags &= ~TUN_RWAIT; 668 669 s = splimp(); 670 do { 671 IF_DEQUEUE(&ifp->if_snd, m); 672 if (m == NULL) { 673 if (flag & IO_NDELAY) { 674 splx(s); 675 return (EWOULDBLOCK); 676 } 677 tp->tun_flags |= TUN_RWAIT; 678 if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), 679 "tunread", 0)) != 0) { 680 splx(s); 681 return (error); 682 } 683 } 684 } while (m == NULL); 685 splx(s); 686 687 while (m && uio->uio_resid > 0 && error == 0) { 688 len = min(uio->uio_resid, m->m_len); 689 if (len != 0) 690 error = uiomove(mtod(m, caddr_t), len, uio); 691 m = m_free(m); 692 } 693 694 if (m) { 695 TUNDEBUG("%s%d: Dropping mbuf\n", ifp->if_name, ifp->if_unit); 696 m_freem(m); 697 } 698 return (error); 699 } 700 701 /* 702 * the cdevsw write interface - an atomic write is a packet - or else! 703 */ 704 static int 705 tunwrite(dev_t dev, struct uio *uio, int flag) 706 { 707 struct tun_softc *tp = dev->si_drv1; 708 struct ifnet *ifp = &tp->tun_if; 709 struct mbuf *top, **mp, *m; 710 int error=0, tlen, mlen; 711 uint32_t family; 712 713 TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); 714 715 if ((ifp->if_flags & IFF_UP) != IFF_UP) 716 /* ignore silently */ 717 return (0); 718 719 if (uio->uio_resid == 0) 720 return (0); 721 722 if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { 723 TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, 724 uio->uio_resid); 725 return (EIO); 726 } 727 tlen = uio->uio_resid; 728 729 /* get a header mbuf */ 730 MGETHDR(m, M_DONTWAIT, MT_DATA); 731 if (m == NULL) 732 return (ENOBUFS); 733 mlen = MHLEN; 734 735 top = 0; 736 mp = ⊤ 737 while (error == 0 && uio->uio_resid > 0) { 738 m->m_len = min(mlen, uio->uio_resid); 739 error = uiomove(mtod (m, caddr_t), m->m_len, uio); 740 *mp = m; 741 mp = &m->m_next; 742 if (uio->uio_resid > 0) { 743 MGET (m, M_DONTWAIT, MT_DATA); 744 if (m == 0) { 745 error = ENOBUFS; 746 break; 747 } 748 mlen = MLEN; 749 } 750 } 751 if (error) { 752 if (top) 753 m_freem (top); 754 ifp->if_ierrors++; 755 return (error); 756 } 757 758 top->m_pkthdr.len = tlen; 759 top->m_pkthdr.rcvif = ifp; 760 #ifdef MAC 761 mac_create_mbuf_from_ifnet(ifp, top); 762 #endif 763 764 if (ifp->if_bpf) { 765 if (tp->tun_flags & TUN_IFHEAD) { 766 /* 767 * Conveniently, we already have a 4-byte address 768 * family prepended to our packet ! 769 * Inconveniently, it's in the wrong byte order ! 770 */ 771 if ((top = m_pullup(top, sizeof(family))) == NULL) 772 return (ENOBUFS); 773 *mtod(top, u_int32_t *) = 774 ntohl(*mtod(top, u_int32_t *)); 775 BPF_MTAP(ifp, top); 776 *mtod(top, u_int32_t *) = 777 htonl(*mtod(top, u_int32_t *)); 778 } else { 779 /* 780 * We need to prepend the address family as 781 * a four byte field. Cons up a dummy header 782 * to pacify bpf. This is safe because bpf 783 * will only read from the mbuf (i.e., it won't 784 * try to free it or keep a pointer to it). 785 */ 786 struct mbuf m; 787 uint32_t af = AF_INET; 788 789 m.m_next = top; 790 m.m_len = 4; 791 m.m_data = (char *)⁡ 792 793 BPF_MTAP(ifp, &m); 794 } 795 } 796 797 if (tp->tun_flags & TUN_IFHEAD) { 798 if (top->m_len < sizeof(family) && 799 (top = m_pullup(top, sizeof(family))) == NULL) 800 return (ENOBUFS); 801 family = ntohl(*mtod(top, u_int32_t *)); 802 m_adj(top, sizeof(family)); 803 } else 804 family = AF_INET; 805 806 ifp->if_ibytes += top->m_pkthdr.len; 807 ifp->if_ipackets++; 808 809 return (family_enqueue(family, top)); 810 } 811 812 /* 813 * tunpoll - the poll interface, this is only useful on reads 814 * really. The write detect always returns true, write never blocks 815 * anyway, it either accepts the packet or drops it. 816 */ 817 static int 818 tunpoll(dev_t dev, int events, struct thread *td) 819 { 820 int s; 821 struct tun_softc *tp = dev->si_drv1; 822 struct ifnet *ifp = &tp->tun_if; 823 int revents = 0; 824 825 s = splimp(); 826 TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); 827 828 if (events & (POLLIN | POLLRDNORM)) { 829 if (ifp->if_snd.ifq_len > 0) { 830 TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, 831 ifp->if_unit, ifp->if_snd.ifq_len); 832 revents |= events & (POLLIN | POLLRDNORM); 833 } else { 834 TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, 835 ifp->if_unit); 836 selrecord(td, &tp->tun_rsel); 837 } 838 } 839 if (events & (POLLOUT | POLLWRNORM)) 840 revents |= events & (POLLOUT | POLLWRNORM); 841 842 splx(s); 843 return (revents); 844 }
Cache object: 46f7d0bcf1f6ee04e9ead2224c57abe7
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