if_tun.c revision 105556
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: head/sys/net/if_tun.c 105556 2002-10-20 20:53:42Z phk $ 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 59static MALLOC_DEFINE(M_TUN, TUNNAME, "Tunnel Interface"); 60static int tundebug = 0; 61static struct tun_softc *tunhead = NULL; 62static struct rman tununits; 63static udev_t tunbasedev = NOUDEV; 64SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); 65 66static void tunclone(void *arg, char *name, int namelen, dev_t *dev); 67static void tuncreate(dev_t dev); 68static int tunifioctl(struct ifnet *, u_long, caddr_t); 69static int tuninit(struct ifnet *); 70static int tunmodevent(module_t, int, void *); 71static int tunoutput(struct ifnet *, struct mbuf *, struct sockaddr *, 72 struct rtentry *rt); 73static void tunstart(struct ifnet *); 74 75static d_open_t tunopen; 76static d_close_t tunclose; 77static d_read_t tunread; 78static d_write_t tunwrite; 79static d_ioctl_t tunioctl; 80static d_poll_t tunpoll; 81 82#define CDEV_MAJOR 52 83static 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 99static void 100tunclone(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 137static int 138tunmodevent(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 210static moduledata_t tun_mod = { 211 "if_tun", 212 tunmodevent, 213 0 214}; 215 216DECLARE_MODULE(if_tun, tun_mod, SI_SUB_PSEUDO, SI_ORDER_ANY); 217 218static void 219tunstart(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 232static void 233tuncreate(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 263static int 264tunopen(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 */ 301static int 302tunclose(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 350static int 351tuninit(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 */ 389static int 390tunifioctl(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 */ 433static int 434tunoutput( 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 /* BPF write needs to be handled specially */ 463 if (dst->sa_family == AF_UNSPEC) { 464 dst->sa_family = *(mtod(m0, int *)); 465 m0->m_len -= sizeof(int); 466 m0->m_pkthdr.len -= sizeof(int); 467 m0->m_data += sizeof(int); 468 } 469 470 if (ifp->if_bpf) { 471 /* 472 * We need to prepend the address family as 473 * a four byte field. Cons up a dummy header 474 * to pacify bpf. This is safe because bpf 475 * will only read from the mbuf (i.e., it won't 476 * try to free it or keep a pointer to it). 477 */ 478 struct mbuf m; 479 uint32_t af = dst->sa_family; 480 481 m.m_next = m0; 482 m.m_len = 4; 483 m.m_data = (char *)⁡ 484 485 bpf_mtap(ifp, &m); 486 } 487 488 /* prepend sockaddr? this may abort if the mbuf allocation fails */ 489 if (tp->tun_flags & TUN_LMODE) { 490 /* allocate space for sockaddr */ 491 M_PREPEND(m0, dst->sa_len, M_DONTWAIT); 492 493 /* if allocation failed drop packet */ 494 if (m0 == NULL) { 495 ifp->if_iqdrops++; 496 ifp->if_oerrors++; 497 return (ENOBUFS); 498 } else { 499 bcopy(dst, m0->m_data, dst->sa_len); 500 } 501 } 502 503 if (tp->tun_flags & TUN_IFHEAD) { 504 /* Prepend the address family */ 505 M_PREPEND(m0, 4, M_DONTWAIT); 506 507 /* if allocation failed drop packet */ 508 if (m0 == NULL) { 509 ifp->if_iqdrops++; 510 ifp->if_oerrors++; 511 return (ENOBUFS); 512 } else 513 *(u_int32_t *)m0->m_data = htonl(dst->sa_family); 514 } else { 515#ifdef INET 516 if (dst->sa_family != AF_INET) 517#endif 518 { 519 m_freem(m0); 520 return (EAFNOSUPPORT); 521 } 522 } 523 524 if (! IF_HANDOFF(&ifp->if_snd, m0, ifp)) { 525 ifp->if_collisions++; 526 return (ENOBUFS); 527 } 528 ifp->if_opackets++; 529 return (0); 530} 531 532/* 533 * the cdevsw interface is now pretty minimal. 534 */ 535static int 536tunioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td) 537{ 538 int s; 539 int error; 540 struct tun_softc *tp = dev->si_drv1; 541 struct tuninfo *tunp; 542 543 switch (cmd) { 544 case TUNSIFINFO: 545 tunp = (struct tuninfo *)data; 546 if (tunp->mtu < IF_MINMTU) 547 return (EINVAL); 548 if (tp->tun_if.if_mtu != tunp->mtu 549 && (error = suser(td)) != 0) 550 return (error); 551 tp->tun_if.if_mtu = tunp->mtu; 552 tp->tun_if.if_type = tunp->type; 553 tp->tun_if.if_baudrate = tunp->baudrate; 554 break; 555 case TUNGIFINFO: 556 tunp = (struct tuninfo *)data; 557 tunp->mtu = tp->tun_if.if_mtu; 558 tunp->type = tp->tun_if.if_type; 559 tunp->baudrate = tp->tun_if.if_baudrate; 560 break; 561 case TUNSDEBUG: 562 tundebug = *(int *)data; 563 break; 564 case TUNGDEBUG: 565 *(int *)data = tundebug; 566 break; 567 case TUNSLMODE: 568 if (*(int *)data) { 569 tp->tun_flags |= TUN_LMODE; 570 tp->tun_flags &= ~TUN_IFHEAD; 571 } else 572 tp->tun_flags &= ~TUN_LMODE; 573 break; 574 case TUNSIFHEAD: 575 if (*(int *)data) { 576 tp->tun_flags |= TUN_IFHEAD; 577 tp->tun_flags &= ~TUN_LMODE; 578 } else 579 tp->tun_flags &= ~TUN_IFHEAD; 580 break; 581 case TUNGIFHEAD: 582 *(int *)data = (tp->tun_flags & TUN_IFHEAD) ? 1 : 0; 583 break; 584 case TUNSIFMODE: 585 /* deny this if UP */ 586 if (tp->tun_if.if_flags & IFF_UP) 587 return(EBUSY); 588 589 switch (*(int *)data & ~IFF_MULTICAST) { 590 case IFF_POINTOPOINT: 591 case IFF_BROADCAST: 592 tp->tun_if.if_flags &= 593 ~(IFF_BROADCAST|IFF_POINTOPOINT|IFF_MULTICAST); 594 tp->tun_if.if_flags |= *(int *)data; 595 break; 596 default: 597 return(EINVAL); 598 } 599 break; 600 case TUNSIFPID: 601 tp->tun_pid = curthread->td_proc->p_pid; 602 break; 603 case FIONBIO: 604 break; 605 case FIOASYNC: 606 if (*(int *)data) 607 tp->tun_flags |= TUN_ASYNC; 608 else 609 tp->tun_flags &= ~TUN_ASYNC; 610 break; 611 case FIONREAD: 612 s = splimp(); 613 if (tp->tun_if.if_snd.ifq_head) { 614 struct mbuf *mb = tp->tun_if.if_snd.ifq_head; 615 for( *(int *)data = 0; mb != 0; mb = mb->m_next) 616 *(int *)data += mb->m_len; 617 } else 618 *(int *)data = 0; 619 splx(s); 620 break; 621 case FIOSETOWN: 622 return (fsetown(*(int *)data, &tp->tun_sigio)); 623 624 case FIOGETOWN: 625 *(int *)data = fgetown(&tp->tun_sigio); 626 return (0); 627 628 /* This is deprecated, FIOSETOWN should be used instead. */ 629 case TIOCSPGRP: 630 return (fsetown(-(*(int *)data), &tp->tun_sigio)); 631 632 /* This is deprecated, FIOGETOWN should be used instead. */ 633 case TIOCGPGRP: 634 *(int *)data = -fgetown(&tp->tun_sigio); 635 return (0); 636 637 default: 638 return (ENOTTY); 639 } 640 return (0); 641} 642 643/* 644 * The cdevsw read interface - reads a packet at a time, or at 645 * least as much of a packet as can be read. 646 */ 647static int 648tunread(dev_t dev, struct uio *uio, int flag) 649{ 650 struct tun_softc *tp = dev->si_drv1; 651 struct ifnet *ifp = &tp->tun_if; 652 struct mbuf *m; 653 int error=0, len, s; 654 655 TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); 656 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 657 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 658 ifp->if_unit, tp->tun_flags); 659 return (EHOSTDOWN); 660 } 661 662 tp->tun_flags &= ~TUN_RWAIT; 663 664 s = splimp(); 665 do { 666 IF_DEQUEUE(&ifp->if_snd, m); 667 if (m == NULL) { 668 if (flag & IO_NDELAY) { 669 splx(s); 670 return (EWOULDBLOCK); 671 } 672 tp->tun_flags |= TUN_RWAIT; 673 if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), 674 "tunread", 0)) != 0) { 675 splx(s); 676 return (error); 677 } 678 } 679 } while (m == NULL); 680 splx(s); 681 682 while (m && uio->uio_resid > 0 && error == 0) { 683 len = min(uio->uio_resid, m->m_len); 684 if (len != 0) 685 error = uiomove(mtod(m, caddr_t), len, uio); 686 m = m_free(m); 687 } 688 689 if (m) { 690 TUNDEBUG("%s%d: Dropping mbuf\n", ifp->if_name, ifp->if_unit); 691 m_freem(m); 692 } 693 return (error); 694} 695 696/* 697 * the cdevsw write interface - an atomic write is a packet - or else! 698 */ 699static int 700tunwrite(dev_t dev, struct uio *uio, int flag) 701{ 702 struct tun_softc *tp = dev->si_drv1; 703 struct ifnet *ifp = &tp->tun_if; 704 struct mbuf *top, **mp, *m; 705 int error=0, tlen, mlen; 706 uint32_t family; 707 708 TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); 709 710 if (uio->uio_resid == 0) 711 return (0); 712 713 if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { 714 TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, 715 uio->uio_resid); 716 return (EIO); 717 } 718 tlen = uio->uio_resid; 719 720 /* get a header mbuf */ 721 MGETHDR(m, M_DONTWAIT, MT_DATA); 722 if (m == NULL) 723 return (ENOBUFS); 724 mlen = MHLEN; 725 726 top = 0; 727 mp = ⊤ 728 while (error == 0 && uio->uio_resid > 0) { 729 m->m_len = min(mlen, uio->uio_resid); 730 error = uiomove(mtod (m, caddr_t), m->m_len, uio); 731 *mp = m; 732 mp = &m->m_next; 733 if (uio->uio_resid > 0) { 734 MGET (m, M_DONTWAIT, MT_DATA); 735 if (m == 0) { 736 error = ENOBUFS; 737 break; 738 } 739 mlen = MLEN; 740 } 741 } 742 if (error) { 743 if (top) 744 m_freem (top); 745 ifp->if_ierrors++; 746 return (error); 747 } 748 749 top->m_pkthdr.len = tlen; 750 top->m_pkthdr.rcvif = ifp; 751#ifdef MAC 752 mac_create_mbuf_from_ifnet(ifp, top); 753#endif 754 755 if (ifp->if_bpf) { 756 if (tp->tun_flags & TUN_IFHEAD) { 757 /* 758 * Conveniently, we already have a 4-byte address 759 * family prepended to our packet ! 760 * Inconveniently, it's in the wrong byte order ! 761 */ 762 if ((top = m_pullup(top, sizeof(family))) == NULL) 763 return (ENOBUFS); 764 *mtod(top, u_int32_t *) = 765 ntohl(*mtod(top, u_int32_t *)); 766 bpf_mtap(ifp, top); 767 *mtod(top, u_int32_t *) = 768 htonl(*mtod(top, u_int32_t *)); 769 } else { 770 /* 771 * We need to prepend the address family as 772 * a four byte field. Cons up a dummy header 773 * to pacify bpf. This is safe because bpf 774 * will only read from the mbuf (i.e., it won't 775 * try to free it or keep a pointer to it). 776 */ 777 struct mbuf m; 778 uint32_t af = AF_INET; 779 780 m.m_next = top; 781 m.m_len = 4; 782 m.m_data = (char *)⁡ 783 784 bpf_mtap(ifp, &m); 785 } 786 } 787 788 if (tp->tun_flags & TUN_IFHEAD) { 789 if (top->m_len < sizeof(family) && 790 (top = m_pullup(top, sizeof(family))) == NULL) 791 return (ENOBUFS); 792 family = ntohl(*mtod(top, u_int32_t *)); 793 m_adj(top, sizeof(family)); 794 } else 795 family = AF_INET; 796 797 ifp->if_ibytes += top->m_pkthdr.len; 798 ifp->if_ipackets++; 799 800 return (family_enqueue(family, top)); 801} 802 803/* 804 * tunpoll - the poll interface, this is only useful on reads 805 * really. The write detect always returns true, write never blocks 806 * anyway, it either accepts the packet or drops it. 807 */ 808static int 809tunpoll(dev_t dev, int events, struct thread *td) 810{ 811 int s; 812 struct tun_softc *tp = dev->si_drv1; 813 struct ifnet *ifp = &tp->tun_if; 814 int revents = 0; 815 816 s = splimp(); 817 TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); 818 819 if (events & (POLLIN | POLLRDNORM)) { 820 if (ifp->if_snd.ifq_len > 0) { 821 TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, 822 ifp->if_unit, ifp->if_snd.ifq_len); 823 revents |= events & (POLLIN | POLLRDNORM); 824 } else { 825 TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, 826 ifp->if_unit); 827 selrecord(td, &tp->tun_rsel); 828 } 829 } 830 if (events & (POLLOUT | POLLWRNORM)) 831 revents |= events & (POLLOUT | POLLWRNORM); 832 833 splx(s); 834 return (revents); 835} 836