if_tun.c revision 48645
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 17#include "tun.h" 18#if NTUN > 0 19 20#include "opt_devfs.h" 21#include "opt_inet.h" 22 23#include <sys/param.h> 24#include <sys/proc.h> 25#include <sys/systm.h> 26#include <sys/mbuf.h> 27#include <sys/socket.h> 28#include <sys/filio.h> 29#include <sys/sockio.h> 30#include <sys/ttycom.h> 31#include <sys/poll.h> 32#include <sys/signalvar.h> 33#include <sys/filedesc.h> 34#include <sys/kernel.h> 35#include <sys/sysctl.h> 36#ifdef DEVFS 37#include <sys/devfsext.h> 38#endif /*DEVFS*/ 39#include <sys/conf.h> 40#include <sys/uio.h> 41#include <sys/vnode.h> 42 43#include <net/if.h> 44#include <net/netisr.h> 45#include <net/route.h> 46 47#ifdef INET 48#include <netinet/in.h> 49#include <netinet/in_var.h> 50#endif 51 52#ifdef NS 53#include <netns/ns.h> 54#include <netns/ns_if.h> 55#endif 56 57#include "bpf.h" 58#if NBPF > 0 59#include <net/bpf.h> 60#endif 61 62#include <net/if_tunvar.h> 63#include <net/if_tun.h> 64 65static void tunattach __P((void *)); 66PSEUDO_SET(tunattach, if_tun); 67 68#define TUNDEBUG if (tundebug) printf 69static int tundebug = 0; 70SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); 71 72static struct tun_softc tunctl[NTUN]; 73 74static int tunoutput __P((struct ifnet *, struct mbuf *, struct sockaddr *, 75 struct rtentry *rt)); 76static int tunifioctl __P((struct ifnet *, u_long, caddr_t)); 77static int tuninit __P((int)); 78 79static d_open_t tunopen; 80static d_close_t tunclose; 81static d_read_t tunread; 82static d_write_t tunwrite; 83static d_ioctl_t tunioctl; 84static d_poll_t tunpoll; 85 86#define CDEV_MAJOR 52 87static struct cdevsw tun_cdevsw = { 88 /* open */ tunopen, 89 /* close */ tunclose, 90 /* read */ tunread, 91 /* write */ tunwrite, 92 /* ioctl */ tunioctl, 93 /* stop */ nostop, 94 /* reset */ noreset, 95 /* devtotty */ nodevtotty, 96 /* poll */ tunpoll, 97 /* mmap */ nommap, 98 /* strategy */ nostrategy, 99 /* name */ "tun", 100 /* parms */ noparms, 101 /* maj */ CDEV_MAJOR, 102 /* dump */ nodump, 103 /* psize */ nopsize, 104 /* flags */ 0, 105 /* maxio */ 0, 106 /* bmaj */ -1 107}; 108 109 110static int tun_devsw_installed; 111#ifdef DEVFS 112static void *tun_devfs_token[NTUN]; 113#endif 114 115#define minor_val(n) ((((n) & ~0xff) << 8) | ((n) & 0xff)) 116#define dev_val(n) (((n) >> 8) | ((n) & 0xff)) 117 118static void 119tunattach(dummy) 120 void *dummy; 121{ 122 register int i; 123 struct ifnet *ifp; 124 125 if ( tun_devsw_installed ) 126 return; 127 cdevsw_add(&tun_cdevsw); 128 tun_devsw_installed = 1; 129 for ( i = 0; i < NTUN; i++ ) { 130#ifdef DEVFS 131 tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, minor_val(i), 132 DV_CHR, UID_UUCP, 133 GID_DIALER, 0600, 134 "tun%d", i); 135#endif 136 tunctl[i].tun_flags = TUN_INITED; 137 138 ifp = &tunctl[i].tun_if; 139 ifp->if_unit = i; 140 ifp->if_name = "tun"; 141 ifp->if_mtu = TUNMTU; 142 ifp->if_ioctl = tunifioctl; 143 ifp->if_output = tunoutput; 144 ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST; 145 ifp->if_snd.ifq_maxlen = ifqmaxlen; 146 if_attach(ifp); 147#if NBPF > 0 148 bpfattach(ifp, DLT_NULL, sizeof(u_int)); 149#endif 150 } 151} 152 153/* 154 * tunnel open - must be superuser & the device must be 155 * configured in 156 */ 157static int 158tunopen(dev, flag, mode, p) 159 dev_t dev; 160 int flag, mode; 161 struct proc *p; 162{ 163 struct ifnet *ifp; 164 struct tun_softc *tp; 165 register int unit, error; 166 167 error = suser(p); 168 if (error) 169 return (error); 170 171 if ((unit = dev_val(minor(dev))) >= NTUN) 172 return (ENXIO); 173 tp = &tunctl[unit]; 174 if (tp->tun_flags & TUN_OPEN) 175 return EBUSY; 176 tp->tun_pid = p->p_pid; 177 ifp = &tp->tun_if; 178 tp->tun_flags |= TUN_OPEN; 179 TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit); 180 return (0); 181} 182 183/* 184 * tunclose - close the device - mark i/f down & delete 185 * routing info 186 */ 187static int 188tunclose(dev, foo, bar, p) 189 dev_t dev; 190 int foo; 191 int bar; 192 struct proc *p; 193{ 194 register int unit = dev_val(minor(dev)), s; 195 struct tun_softc *tp = &tunctl[unit]; 196 struct ifnet *ifp = &tp->tun_if; 197 struct mbuf *m; 198 199 tp->tun_flags &= ~TUN_OPEN; 200 tp->tun_pid = 0; 201 202 /* 203 * junk all pending output 204 */ 205 do { 206 s = splimp(); 207 IF_DEQUEUE(&ifp->if_snd, m); 208 splx(s); 209 if (m) 210 m_freem(m); 211 } while (m); 212 213 if (ifp->if_flags & IFF_UP) { 214 s = splimp(); 215 if_down(ifp); 216 splx(s); 217 } 218 219 if (ifp->if_flags & IFF_RUNNING) { 220 register struct ifaddr *ifa; 221 222 s = splimp(); 223 /* find internet addresses and delete routes */ 224 for (ifa = ifp->if_addrhead.tqh_first; ifa; 225 ifa = ifa->ifa_link.tqe_next) 226 if (ifa->ifa_addr->sa_family == AF_INET) 227 rtinit(ifa, (int)RTM_DELETE, 228 tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0); 229 ifp->if_flags &= ~IFF_RUNNING; 230 splx(s); 231 } 232 233 funsetown(tp->tun_sigio); 234 selwakeup(&tp->tun_rsel); 235 236 TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); 237 return (0); 238} 239 240static int 241tuninit(unit) 242 int unit; 243{ 244 struct tun_softc *tp = &tunctl[unit]; 245 struct ifnet *ifp = &tp->tun_if; 246 register struct ifaddr *ifa; 247 248 TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit); 249 250 ifp->if_flags |= IFF_UP | IFF_RUNNING; 251 getmicrotime(&ifp->if_lastchange); 252 253 for (ifa = ifp->if_addrhead.tqh_first; ifa; 254 ifa = ifa->ifa_link.tqe_next) { 255#ifdef INET 256 if (ifa->ifa_addr->sa_family == AF_INET) { 257 struct sockaddr_in *si; 258 259 si = (struct sockaddr_in *)ifa->ifa_addr; 260 if (si && si->sin_addr.s_addr) 261 tp->tun_flags |= TUN_IASET; 262 263 si = (struct sockaddr_in *)ifa->ifa_dstaddr; 264 if (si && si->sin_addr.s_addr) 265 tp->tun_flags |= TUN_DSTADDR; 266 } 267#endif 268 } 269 return 0; 270} 271 272/* 273 * Process an ioctl request. 274 */ 275int 276tunifioctl(ifp, cmd, data) 277 struct ifnet *ifp; 278 u_long cmd; 279 caddr_t data; 280{ 281 struct ifreq *ifr = (struct ifreq *)data; 282 struct tun_softc *tp = &tunctl[ifp->if_unit]; 283 struct ifstat *ifs; 284 int error = 0, s; 285 286 s = splimp(); 287 switch(cmd) { 288 case SIOCGIFSTATUS: 289 ifs = (struct ifstat *)data; 290 if (tp->tun_pid) 291 sprintf(ifs->ascii + strlen(ifs->ascii), 292 "\tOpened by PID %d\n", tp->tun_pid); 293 return(0); 294 case SIOCSIFADDR: 295 tuninit(ifp->if_unit); 296 TUNDEBUG("%s%d: address set\n", 297 ifp->if_name, ifp->if_unit); 298 break; 299 case SIOCSIFDSTADDR: 300 tuninit(ifp->if_unit); 301 TUNDEBUG("%s%d: destination address set\n", 302 ifp->if_name, ifp->if_unit); 303 break; 304 case SIOCSIFMTU: 305 ifp->if_mtu = ifr->ifr_mtu; 306 TUNDEBUG("%s%d: mtu set\n", 307 ifp->if_name, ifp->if_unit); 308 break; 309 case SIOCADDMULTI: 310 case SIOCDELMULTI: 311 break; 312 313 314 default: 315 error = EINVAL; 316 } 317 splx(s); 318 return (error); 319} 320 321/* 322 * tunoutput - queue packets from higher level ready to put out. 323 */ 324int 325tunoutput(ifp, m0, dst, rt) 326 struct ifnet *ifp; 327 struct mbuf *m0; 328 struct sockaddr *dst; 329 struct rtentry *rt; 330{ 331 struct tun_softc *tp = &tunctl[ifp->if_unit]; 332 int s; 333 334 TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit); 335 336 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 337 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 338 ifp->if_unit, tp->tun_flags); 339 m_freem (m0); 340 return EHOSTDOWN; 341 } 342 343#if NBPF > 0 344 /* BPF write needs to be handled specially */ 345 if (dst->sa_family == AF_UNSPEC) { 346 dst->sa_family = *(mtod(m0, int *)); 347 m0->m_len -= sizeof(int); 348 m0->m_pkthdr.len -= sizeof(int); 349 m0->m_data += sizeof(int); 350 } 351 352 if (ifp->if_bpf) { 353 /* 354 * We need to prepend the address family as 355 * a four byte field. Cons up a dummy header 356 * to pacify bpf. This is safe because bpf 357 * will only read from the mbuf (i.e., it won't 358 * try to free it or keep a pointer to it). 359 */ 360 struct mbuf m; 361 u_int af = dst->sa_family; 362 363 m.m_next = m0; 364 m.m_len = 4; 365 m.m_data = (char *)⁡ 366 367 bpf_mtap(ifp, &m); 368 } 369#endif /* NBPF > 0 */ 370 371 /* prepend sockaddr? this may abort if the mbuf allocation fails */ 372 if (tp->tun_flags & TUN_LMODE) { 373 /* allocate space for sockaddr */ 374 M_PREPEND(m0, dst->sa_len, M_DONTWAIT); 375 376 /* if allocation failed drop packet */ 377 if (m0 == NULL){ 378 s = splimp(); /* spl on queue manipulation */ 379 IF_DROP(&ifp->if_snd); 380 splx(s); 381 ifp->if_oerrors++; 382 return (ENOBUFS); 383 } else { 384 bcopy(dst, m0->m_data, dst->sa_len); 385 } 386 } 387 388 switch(dst->sa_family) { 389#ifdef INET 390 case AF_INET: 391 s = splimp(); 392 if (IF_QFULL(&ifp->if_snd)) { 393 IF_DROP(&ifp->if_snd); 394 m_freem(m0); 395 splx(s); 396 ifp->if_collisions++; 397 return (ENOBUFS); 398 } 399 ifp->if_obytes += m0->m_pkthdr.len; 400 IF_ENQUEUE(&ifp->if_snd, m0); 401 splx(s); 402 ifp->if_opackets++; 403 break; 404#endif 405 default: 406 m_freem(m0); 407 return EAFNOSUPPORT; 408 } 409 410 if (tp->tun_flags & TUN_RWAIT) { 411 tp->tun_flags &= ~TUN_RWAIT; 412 wakeup((caddr_t)tp); 413 } 414 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) 415 pgsigio(tp->tun_sigio, SIGIO, 0); 416 selwakeup(&tp->tun_rsel); 417 return 0; 418} 419 420/* 421 * the cdevsw interface is now pretty minimal. 422 */ 423static int 424tunioctl(dev, cmd, data, flag, p) 425 dev_t dev; 426 u_long cmd; 427 caddr_t data; 428 int flag; 429 struct proc *p; 430{ 431 int unit = dev_val(minor(dev)), s; 432 struct tun_softc *tp = &tunctl[unit]; 433 struct tuninfo *tunp; 434 435 switch (cmd) { 436 case TUNSIFINFO: 437 tunp = (struct tuninfo *)data; 438 tp->tun_if.if_mtu = tunp->mtu; 439 tp->tun_if.if_type = tunp->type; 440 tp->tun_if.if_baudrate = tunp->baudrate; 441 break; 442 case TUNGIFINFO: 443 tunp = (struct tuninfo *)data; 444 tunp->mtu = tp->tun_if.if_mtu; 445 tunp->type = tp->tun_if.if_type; 446 tunp->baudrate = tp->tun_if.if_baudrate; 447 break; 448 case TUNSDEBUG: 449 tundebug = *(int *)data; 450 break; 451 case TUNGDEBUG: 452 *(int *)data = tundebug; 453 break; 454 case TUNSLMODE: 455 if (*(int *)data) 456 tp->tun_flags |= TUN_LMODE; 457 else 458 tp->tun_flags &= ~TUN_LMODE; 459 break; 460 case TUNSIFMODE: 461 /* deny this if UP */ 462 if (tp->tun_if.if_flags & IFF_UP) 463 return(EBUSY); 464 465 switch (*(int *)data) { 466 case IFF_POINTOPOINT: 467 tp->tun_if.if_flags |= IFF_POINTOPOINT; 468 tp->tun_if.if_flags &= ~IFF_BROADCAST; 469 break; 470 case IFF_BROADCAST: 471 tp->tun_if.if_flags &= ~IFF_POINTOPOINT; 472 tp->tun_if.if_flags |= IFF_BROADCAST; 473 break; 474 default: 475 return(EINVAL); 476 } 477 break; 478 case FIONBIO: 479 break; 480 case FIOASYNC: 481 if (*(int *)data) 482 tp->tun_flags |= TUN_ASYNC; 483 else 484 tp->tun_flags &= ~TUN_ASYNC; 485 break; 486 case FIONREAD: 487 s = splimp(); 488 if (tp->tun_if.if_snd.ifq_head) { 489 struct mbuf *mb = tp->tun_if.if_snd.ifq_head; 490 for( *(int *)data = 0; mb != 0; mb = mb->m_next) 491 *(int *)data += mb->m_len; 492 } else 493 *(int *)data = 0; 494 splx(s); 495 break; 496 case FIOSETOWN: 497 return (fsetown(*(int *)data, &tp->tun_sigio)); 498 499 case FIOGETOWN: 500 *(int *)data = fgetown(tp->tun_sigio); 501 return (0); 502 503 /* This is deprecated, FIOSETOWN should be used instead. */ 504 case TIOCSPGRP: 505 return (fsetown(-(*(int *)data), &tp->tun_sigio)); 506 507 /* This is deprecated, FIOGETOWN should be used instead. */ 508 case TIOCGPGRP: 509 *(int *)data = -fgetown(tp->tun_sigio); 510 return (0); 511 512 default: 513 return (ENOTTY); 514 } 515 return (0); 516} 517 518/* 519 * The cdevsw read interface - reads a packet at a time, or at 520 * least as much of a packet as can be read. 521 */ 522static int 523tunread(dev, uio, flag) 524 dev_t dev; 525 struct uio *uio; 526 int flag; 527{ 528 int unit = dev_val(minor(dev)); 529 struct tun_softc *tp = &tunctl[unit]; 530 struct ifnet *ifp = &tp->tun_if; 531 struct mbuf *m, *m0; 532 int error=0, len, s; 533 534 TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); 535 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 536 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 537 ifp->if_unit, tp->tun_flags); 538 return EHOSTDOWN; 539 } 540 541 tp->tun_flags &= ~TUN_RWAIT; 542 543 s = splimp(); 544 do { 545 IF_DEQUEUE(&ifp->if_snd, m0); 546 if (m0 == 0) { 547 if (flag & IO_NDELAY) { 548 splx(s); 549 return EWOULDBLOCK; 550 } 551 tp->tun_flags |= TUN_RWAIT; 552 if((error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), 553 "tunread", 0)) != 0) { 554 splx(s); 555 return error; 556 } 557 } 558 } while (m0 == 0); 559 splx(s); 560 561 while (m0 && uio->uio_resid > 0 && error == 0) { 562 len = min(uio->uio_resid, m0->m_len); 563 if (len == 0) 564 break; 565 error = uiomove(mtod(m0, caddr_t), len, uio); 566 MFREE(m0, m); 567 m0 = m; 568 } 569 570 if (m0) { 571 TUNDEBUG("Dropping mbuf\n"); 572 m_freem(m0); 573 } 574 return error; 575} 576 577/* 578 * the cdevsw write interface - an atomic write is a packet - or else! 579 */ 580static int 581tunwrite(dev, uio, flag) 582 dev_t dev; 583 struct uio *uio; 584 int flag; 585{ 586 int unit = dev_val(minor(dev)); 587 struct ifnet *ifp = &tunctl[unit].tun_if; 588 struct mbuf *top, **mp, *m; 589 int error=0, s, tlen, mlen; 590 591 TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); 592 593 if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { 594 TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, 595 uio->uio_resid); 596 return EIO; 597 } 598 tlen = uio->uio_resid; 599 600 /* get a header mbuf */ 601 MGETHDR(m, M_DONTWAIT, MT_DATA); 602 if (m == NULL) 603 return ENOBUFS; 604 mlen = MHLEN; 605 606 top = 0; 607 mp = ⊤ 608 while (error == 0 && uio->uio_resid > 0) { 609 m->m_len = min(mlen, uio->uio_resid); 610 error = uiomove(mtod (m, caddr_t), m->m_len, uio); 611 *mp = m; 612 mp = &m->m_next; 613 if (uio->uio_resid > 0) { 614 MGET (m, M_DONTWAIT, MT_DATA); 615 if (m == 0) { 616 error = ENOBUFS; 617 break; 618 } 619 mlen = MLEN; 620 } 621 } 622 if (error) { 623 if (top) 624 m_freem (top); 625 return error; 626 } 627 628 top->m_pkthdr.len = tlen; 629 top->m_pkthdr.rcvif = ifp; 630 631#if NBPF > 0 632 if (ifp->if_bpf) { 633 /* 634 * We need to prepend the address family as 635 * a four byte field. Cons up a dummy header 636 * to pacify bpf. This is safe because bpf 637 * will only read from the mbuf (i.e., it won't 638 * try to free it or keep a pointer to it). 639 */ 640 struct mbuf m; 641 u_int af = AF_INET; 642 643 m.m_next = top; 644 m.m_len = 4; 645 m.m_data = (char *)⁡ 646 647 bpf_mtap(ifp, &m); 648 } 649#endif 650 651#ifdef INET 652 s = splimp(); 653 if (IF_QFULL (&ipintrq)) { 654 IF_DROP(&ipintrq); 655 splx(s); 656 ifp->if_collisions++; 657 m_freem(top); 658 return ENOBUFS; 659 } 660 IF_ENQUEUE(&ipintrq, top); 661 splx(s); 662 ifp->if_ibytes += tlen; 663 ifp->if_ipackets++; 664 schednetisr(NETISR_IP); 665#endif 666 return error; 667} 668 669/* 670 * tunpoll - the poll interface, this is only useful on reads 671 * really. The write detect always returns true, write never blocks 672 * anyway, it either accepts the packet or drops it. 673 */ 674static int 675tunpoll(dev, events, p) 676 dev_t dev; 677 int events; 678 struct proc *p; 679{ 680 int unit = dev_val(minor(dev)), s; 681 struct tun_softc *tp = &tunctl[unit]; 682 struct ifnet *ifp = &tp->tun_if; 683 int revents = 0; 684 685 s = splimp(); 686 TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); 687 688 if (events & (POLLIN | POLLRDNORM)) { 689 if (ifp->if_snd.ifq_len > 0) { 690 TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, 691 ifp->if_unit, ifp->if_snd.ifq_len); 692 revents |= events & (POLLIN | POLLRDNORM); 693 } else { 694 TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, 695 ifp->if_unit); 696 selrecord(p, &tp->tun_rsel); 697 } 698 } 699 if (events & (POLLOUT | POLLWRNORM)) 700 revents |= events & (POLLOUT | POLLWRNORM); 701 702 splx(s); 703 return (revents); 704} 705 706 707#endif /* NTUN */ 708