Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/net/if_tun.c
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1 /* $FreeBSD$ */ 2 /* $NetBSD: if_tun.c,v 1.14 1994/06/29 06:36:25 cgd Exp $ */ 3 4 /* 5 * Copyright (c) 1988, Julian Onions <jpo@cs.nott.ac.uk> 6 * Nottingham University 1987. 7 * 8 * This source may be freely distributed, however I would be interested 9 * in any changes that are made. 10 * 11 * This driver takes packets off the IP i/f and hands them up to a 12 * user process to have its wicked way with. This driver has it's 13 * roots in a similar driver written by Phil Cockcroft (formerly) at 14 * UCL. This driver is based much more on read/write/poll mode of 15 * operation though. 16 */ 17 18 #include "tun.h" 19 #if NTUN > 0 20 21 #include "opt_devfs.h" 22 #include "opt_inet.h" 23 24 #include <sys/param.h> 25 #include <sys/proc.h> 26 #include <sys/systm.h> 27 #include <sys/mbuf.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 #ifdef DEVFS 38 #include <sys/devfsext.h> 39 #endif /*DEVFS*/ 40 #include <sys/conf.h> 41 #include <sys/uio.h> 42 #include <sys/vnode.h> 43 44 #include <net/if.h> 45 #include <net/netisr.h> 46 #include <net/route.h> 47 48 #ifdef INET 49 #include <netinet/in.h> 50 #include <netinet/in_var.h> 51 #endif 52 53 #ifdef NS 54 #include <netns/ns.h> 55 #include <netns/ns_if.h> 56 #endif 57 58 #include "bpfilter.h" 59 #if NBPFILTER > 0 60 #include <net/bpf.h> 61 #endif 62 63 #include <net/if_tunvar.h> 64 #include <net/if_tun.h> 65 66 static void tunattach __P((void *)); 67 PSEUDO_SET(tunattach, if_tun); 68 69 #define TUNDEBUG if (tundebug) printf 70 static int tundebug = 0; 71 SYSCTL_INT(_debug, OID_AUTO, if_tun_debug, CTLFLAG_RW, &tundebug, 0, ""); 72 73 static struct tun_softc tunctl[NTUN]; 74 75 static int tunoutput __P((struct ifnet *, struct mbuf *, struct sockaddr *, 76 struct rtentry *rt)); 77 static int tunifioctl __P((struct ifnet *, u_long, caddr_t)); 78 static int tuninit __P((int)); 79 80 static d_open_t tunopen; 81 static d_close_t tunclose; 82 static d_read_t tunread; 83 static d_write_t tunwrite; 84 static d_ioctl_t tunioctl; 85 static d_poll_t tunpoll; 86 87 #define CDEV_MAJOR 52 88 static struct cdevsw tun_cdevsw = { 89 tunopen, tunclose, tunread, tunwrite, 90 tunioctl, nullstop, noreset, nodevtotty, 91 tunpoll, nommap, nostrategy, "tun", NULL, -1 92 }; 93 94 95 static int tun_devsw_installed; 96 #ifdef DEVFS 97 static void *tun_devfs_token[NTUN]; 98 #endif 99 100 #define minor_val(n) ((((n) & ~0xff) << 8) | ((n) & 0xff)) 101 #define dev_val(n) (((n) >> 8) | ((n) & 0xff)) 102 103 static void 104 tunattach(dummy) 105 void *dummy; 106 { 107 register int i; 108 struct ifnet *ifp; 109 dev_t dev; 110 111 if ( tun_devsw_installed ) 112 return; 113 dev = makedev(CDEV_MAJOR, 0); 114 cdevsw_add(&dev, &tun_cdevsw, NULL); 115 tun_devsw_installed = 1; 116 for ( i = 0; i < NTUN; i++ ) { 117 #ifdef DEVFS 118 tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, minor_val(i), 119 DV_CHR, UID_UUCP, 120 GID_DIALER, 0600, 121 "tun%d", i); 122 #endif 123 tunctl[i].tun_flags = TUN_INITED; 124 125 ifp = &tunctl[i].tun_if; 126 ifp->if_unit = i; 127 ifp->if_name = "tun"; 128 ifp->if_mtu = TUNMTU; 129 ifp->if_ioctl = tunifioctl; 130 ifp->if_output = tunoutput; 131 ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST; 132 ifp->if_snd.ifq_maxlen = ifqmaxlen; 133 if_attach(ifp); 134 #if NBPFILTER > 0 135 bpfattach(ifp, DLT_NULL, sizeof(u_int)); 136 #endif 137 } 138 } 139 140 /* 141 * tunnel open - must be superuser & the device must be 142 * configured in 143 */ 144 static int 145 tunopen(dev, flag, mode, p) 146 dev_t dev; 147 int flag, mode; 148 struct proc *p; 149 { 150 struct ifnet *ifp; 151 struct tun_softc *tp; 152 register int unit, error; 153 154 error = suser(p->p_ucred, &p->p_acflag); 155 if (error) 156 return (error); 157 158 if ((unit = dev_val(minor(dev))) >= NTUN) 159 return (ENXIO); 160 tp = &tunctl[unit]; 161 if (tp->tun_flags & TUN_OPEN) 162 return EBUSY; 163 ifp = &tp->tun_if; 164 tp->tun_flags |= TUN_OPEN; 165 TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit); 166 return (0); 167 } 168 169 /* 170 * tunclose - close the device - mark i/f down & delete 171 * routing info 172 */ 173 static int 174 tunclose(dev, foo, bar, p) 175 dev_t dev; 176 int foo; 177 int bar; 178 struct proc *p; 179 { 180 register int unit = dev_val(minor(dev)), s; 181 struct tun_softc *tp = &tunctl[unit]; 182 struct ifnet *ifp = &tp->tun_if; 183 struct mbuf *m; 184 185 tp->tun_flags &= ~TUN_OPEN; 186 187 /* 188 * junk all pending output 189 */ 190 do { 191 s = splimp(); 192 IF_DEQUEUE(&ifp->if_snd, m); 193 splx(s); 194 if (m) 195 m_freem(m); 196 } while (m); 197 198 if (ifp->if_flags & IFF_UP) { 199 s = splimp(); 200 if_down(ifp); 201 if (ifp->if_flags & IFF_RUNNING) { 202 /* find internet addresses and delete routes */ 203 register struct ifaddr *ifa; 204 for (ifa = ifp->if_addrhead.tqh_first; ifa; 205 ifa = ifa->ifa_link.tqe_next) { 206 if (ifa->ifa_addr->sa_family == AF_INET) { 207 rtinit(ifa, (int)RTM_DELETE, 208 tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0); 209 } 210 } 211 } 212 splx(s); 213 } 214 funsetown(tp->tun_sigio); 215 selwakeup(&tp->tun_rsel); 216 217 TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); 218 return (0); 219 } 220 221 static int 222 tuninit(unit) 223 int unit; 224 { 225 struct tun_softc *tp = &tunctl[unit]; 226 struct ifnet *ifp = &tp->tun_if; 227 register struct ifaddr *ifa; 228 229 TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit); 230 231 ifp->if_flags |= IFF_UP | IFF_RUNNING; 232 getmicrotime(&ifp->if_lastchange); 233 234 for (ifa = ifp->if_addrhead.tqh_first; ifa; 235 ifa = ifa->ifa_link.tqe_next) { 236 #ifdef INET 237 if (ifa->ifa_addr->sa_family == AF_INET) { 238 struct sockaddr_in *si; 239 240 si = (struct sockaddr_in *)ifa->ifa_addr; 241 if (si && si->sin_addr.s_addr) 242 tp->tun_flags |= TUN_IASET; 243 244 si = (struct sockaddr_in *)ifa->ifa_dstaddr; 245 if (si && si->sin_addr.s_addr) 246 tp->tun_flags |= TUN_DSTADDR; 247 } 248 #endif 249 } 250 return 0; 251 } 252 253 /* 254 * Process an ioctl request. 255 */ 256 int 257 tunifioctl(ifp, cmd, data) 258 struct ifnet *ifp; 259 u_long cmd; 260 caddr_t data; 261 { 262 register struct ifreq *ifr = (struct ifreq *)data; 263 int error = 0, s; 264 265 s = splimp(); 266 switch(cmd) { 267 case SIOCSIFADDR: 268 tuninit(ifp->if_unit); 269 TUNDEBUG("%s%d: address set\n", 270 ifp->if_name, ifp->if_unit); 271 break; 272 case SIOCSIFDSTADDR: 273 tuninit(ifp->if_unit); 274 TUNDEBUG("%s%d: destination address set\n", 275 ifp->if_name, ifp->if_unit); 276 break; 277 case SIOCSIFMTU: 278 ifp->if_mtu = ifr->ifr_mtu; 279 TUNDEBUG("%s%d: mtu set\n", 280 ifp->if_name, ifp->if_unit); 281 break; 282 case SIOCADDMULTI: 283 case SIOCDELMULTI: 284 break; 285 286 287 default: 288 error = EINVAL; 289 } 290 splx(s); 291 return (error); 292 } 293 294 /* 295 * tunoutput - queue packets from higher level ready to put out. 296 */ 297 int 298 tunoutput(ifp, m0, dst, rt) 299 struct ifnet *ifp; 300 struct mbuf *m0; 301 struct sockaddr *dst; 302 struct rtentry *rt; 303 { 304 struct tun_softc *tp = &tunctl[ifp->if_unit]; 305 int s; 306 307 TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit); 308 309 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 310 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 311 ifp->if_unit, tp->tun_flags); 312 m_freem (m0); 313 return EHOSTDOWN; 314 } 315 316 #if NBPFILTER > 0 317 /* BPF write needs to be handled specially */ 318 if (dst->sa_family == AF_UNSPEC) { 319 dst->sa_family = *(mtod(m0, int *)); 320 m0->m_len -= sizeof(int); 321 m0->m_pkthdr.len -= sizeof(int); 322 m0->m_data += sizeof(int); 323 } 324 325 if (ifp->if_bpf) { 326 /* 327 * We need to prepend the address family as 328 * a four byte field. Cons up a dummy header 329 * to pacify bpf. This is safe because bpf 330 * will only read from the mbuf (i.e., it won't 331 * try to free it or keep a pointer to it). 332 */ 333 struct mbuf m; 334 u_int af = dst->sa_family; 335 336 m.m_next = m0; 337 m.m_len = 4; 338 m.m_data = (char *)⁡ 339 340 bpf_mtap(ifp, &m); 341 } 342 #endif 343 344 switch(dst->sa_family) { 345 #ifdef INET 346 case AF_INET: 347 s = splimp(); 348 if (IF_QFULL(&ifp->if_snd)) { 349 IF_DROP(&ifp->if_snd); 350 m_freem(m0); 351 splx(s); 352 ifp->if_collisions++; 353 return (ENOBUFS); 354 } 355 ifp->if_obytes += m0->m_pkthdr.len; 356 IF_ENQUEUE(&ifp->if_snd, m0); 357 splx(s); 358 ifp->if_opackets++; 359 break; 360 #endif 361 default: 362 m_freem(m0); 363 return EAFNOSUPPORT; 364 } 365 366 if (tp->tun_flags & TUN_RWAIT) { 367 tp->tun_flags &= ~TUN_RWAIT; 368 wakeup((caddr_t)tp); 369 } 370 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) 371 pgsigio(tp->tun_sigio, SIGIO, 0); 372 selwakeup(&tp->tun_rsel); 373 return 0; 374 } 375 376 /* 377 * the cdevsw interface is now pretty minimal. 378 */ 379 static int 380 tunioctl(dev, cmd, data, flag, p) 381 dev_t dev; 382 u_long cmd; 383 caddr_t data; 384 int flag; 385 struct proc *p; 386 { 387 int unit = dev_val(minor(dev)), s; 388 struct tun_softc *tp = &tunctl[unit]; 389 struct tuninfo *tunp; 390 391 switch (cmd) { 392 case TUNSIFINFO: 393 tunp = (struct tuninfo *)data; 394 if (tunp->mtu < IF_MINMTU) 395 return (EINVAL); 396 tp->tun_if.if_mtu = tunp->mtu; 397 tp->tun_if.if_type = tunp->type; 398 tp->tun_if.if_baudrate = tunp->baudrate; 399 break; 400 case TUNGIFINFO: 401 tunp = (struct tuninfo *)data; 402 tunp->mtu = tp->tun_if.if_mtu; 403 tunp->type = tp->tun_if.if_type; 404 tunp->baudrate = tp->tun_if.if_baudrate; 405 break; 406 case TUNSDEBUG: 407 tundebug = *(int *)data; 408 break; 409 case TUNGDEBUG: 410 *(int *)data = tundebug; 411 break; 412 case FIONBIO: 413 break; 414 case FIOASYNC: 415 if (*(int *)data) 416 tp->tun_flags |= TUN_ASYNC; 417 else 418 tp->tun_flags &= ~TUN_ASYNC; 419 break; 420 case FIONREAD: 421 s = splimp(); 422 if (tp->tun_if.if_snd.ifq_head) { 423 struct mbuf *mb = tp->tun_if.if_snd.ifq_head; 424 for( *(int *)data = 0; mb != 0; mb = mb->m_next) 425 *(int *)data += mb->m_len; 426 } else 427 *(int *)data = 0; 428 splx(s); 429 break; 430 case FIOSETOWN: 431 return (fsetown(*(int *)data, &tp->tun_sigio)); 432 433 case FIOGETOWN: 434 *(int *)data = fgetown(tp->tun_sigio); 435 return (0); 436 437 /* This is deprecated, FIOSETOWN should be used instead. */ 438 case TIOCSPGRP: 439 return (fsetown(-(*(int *)data), &tp->tun_sigio)); 440 441 /* This is deprecated, FIOGETOWN should be used instead. */ 442 case TIOCGPGRP: 443 *(int *)data = -fgetown(tp->tun_sigio); 444 return (0); 445 446 default: 447 return (ENOTTY); 448 } 449 return (0); 450 } 451 452 /* 453 * The cdevsw read interface - reads a packet at a time, or at 454 * least as much of a packet as can be read. 455 */ 456 static int 457 tunread(dev, uio, flag) 458 dev_t dev; 459 struct uio *uio; 460 int flag; 461 { 462 int unit = dev_val(minor(dev)); 463 struct tun_softc *tp = &tunctl[unit]; 464 struct ifnet *ifp = &tp->tun_if; 465 struct mbuf *m, *m0; 466 int error=0, len, s; 467 468 TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); 469 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 470 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 471 ifp->if_unit, tp->tun_flags); 472 return EHOSTDOWN; 473 } 474 475 tp->tun_flags &= ~TUN_RWAIT; 476 477 s = splimp(); 478 do { 479 IF_DEQUEUE(&ifp->if_snd, m0); 480 if (m0 == 0) { 481 if (flag & IO_NDELAY) { 482 splx(s); 483 return EWOULDBLOCK; 484 } 485 tp->tun_flags |= TUN_RWAIT; 486 if( error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), 487 "tunread", 0)) { 488 splx(s); 489 return error; 490 } 491 } 492 } while (m0 == 0); 493 splx(s); 494 495 while (m0 && uio->uio_resid > 0 && error == 0) { 496 len = min(uio->uio_resid, m0->m_len); 497 if (len == 0) 498 break; 499 error = uiomove(mtod(m0, caddr_t), len, uio); 500 MFREE(m0, m); 501 m0 = m; 502 } 503 504 if (m0) { 505 TUNDEBUG("Dropping mbuf\n"); 506 m_freem(m0); 507 } 508 return error; 509 } 510 511 /* 512 * the cdevsw write interface - an atomic write is a packet - or else! 513 */ 514 static int 515 tunwrite(dev, uio, flag) 516 dev_t dev; 517 struct uio *uio; 518 int flag; 519 { 520 int unit = dev_val(minor(dev)); 521 struct ifnet *ifp = &tunctl[unit].tun_if; 522 struct mbuf *top, **mp, *m; 523 int error=0, s, tlen, mlen; 524 525 TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); 526 527 if (uio->uio_resid == 0) 528 return 0; 529 530 if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { 531 TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, 532 uio->uio_resid); 533 return EIO; 534 } 535 tlen = uio->uio_resid; 536 537 /* get a header mbuf */ 538 MGETHDR(m, M_DONTWAIT, MT_DATA); 539 if (m == NULL) 540 return ENOBUFS; 541 mlen = MHLEN; 542 543 top = 0; 544 mp = ⊤ 545 while (error == 0 && uio->uio_resid > 0) { 546 m->m_len = min(mlen, uio->uio_resid); 547 error = uiomove(mtod (m, caddr_t), m->m_len, uio); 548 *mp = m; 549 mp = &m->m_next; 550 if (uio->uio_resid > 0) { 551 MGET (m, M_DONTWAIT, MT_DATA); 552 if (m == 0) { 553 error = ENOBUFS; 554 break; 555 } 556 mlen = MLEN; 557 } 558 } 559 if (error) { 560 if (top) 561 m_freem (top); 562 return error; 563 } 564 565 top->m_pkthdr.len = tlen; 566 top->m_pkthdr.rcvif = ifp; 567 568 #if NBPFILTER > 0 569 if (ifp->if_bpf) { 570 /* 571 * We need to prepend the address family as 572 * a four byte field. Cons up a dummy header 573 * to pacify bpf. This is safe because bpf 574 * will only read from the mbuf (i.e., it won't 575 * try to free it or keep a pointer to it). 576 */ 577 struct mbuf m; 578 u_int af = AF_INET; 579 580 m.m_next = top; 581 m.m_len = 4; 582 m.m_data = (char *)⁡ 583 584 bpf_mtap(ifp, &m); 585 } 586 #endif 587 588 #ifdef INET 589 s = splimp(); 590 if (IF_QFULL (&ipintrq)) { 591 IF_DROP(&ipintrq); 592 splx(s); 593 ifp->if_collisions++; 594 m_freem(top); 595 return ENOBUFS; 596 } 597 IF_ENQUEUE(&ipintrq, top); 598 splx(s); 599 ifp->if_ibytes += tlen; 600 ifp->if_ipackets++; 601 schednetisr(NETISR_IP); 602 #endif 603 return error; 604 } 605 606 /* 607 * tunpoll - the poll interface, this is only useful on reads 608 * really. The write detect always returns true, write never blocks 609 * anyway, it either accepts the packet or drops it. 610 */ 611 static int 612 tunpoll(dev, events, p) 613 dev_t dev; 614 int events; 615 struct proc *p; 616 { 617 int unit = dev_val(minor(dev)), s; 618 struct tun_softc *tp = &tunctl[unit]; 619 struct ifnet *ifp = &tp->tun_if; 620 int revents = 0; 621 622 s = splimp(); 623 TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); 624 625 if (events & (POLLIN | POLLRDNORM)) 626 if (ifp->if_snd.ifq_len > 0) { 627 TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, 628 ifp->if_unit, ifp->if_snd.ifq_len); 629 revents |= events & (POLLIN | POLLRDNORM); 630 } else { 631 TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, 632 ifp->if_unit); 633 selrecord(p, &tp->tun_rsel); 634 } 635 636 if (events & (POLLOUT | POLLWRNORM)) 637 revents |= events & (POLLOUT | POLLWRNORM); 638 639 splx(s); 640 return (revents); 641 } 642 643 644 #endif /* NTUN */
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