if_tun.c revision 42769
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 "bpfilter.h" 58#if NBPFILTER > 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 tunopen, tunclose, tunread, tunwrite, 89 tunioctl, nullstop, noreset, nodevtotty, 90 tunpoll, nommap, nostrategy, "tun", NULL, -1 91}; 92 93 94static int tun_devsw_installed; 95#ifdef DEVFS 96static void *tun_devfs_token[NTUN]; 97#endif 98 99#define minor_val(n) ((((n) & ~0xff) << 8) | ((n) & 0xff)) 100#define dev_val(n) (((n) >> 8) | ((n) & 0xff)) 101 102static void 103tunattach(dummy) 104 void *dummy; 105{ 106 register int i; 107 struct ifnet *ifp; 108 dev_t dev; 109 110 if ( tun_devsw_installed ) 111 return; 112 dev = makedev(CDEV_MAJOR, 0); 113 cdevsw_add(&dev, &tun_cdevsw, NULL); 114 tun_devsw_installed = 1; 115 for ( i = 0; i < NTUN; i++ ) { 116#ifdef DEVFS 117 tun_devfs_token[i] = devfs_add_devswf(&tun_cdevsw, minor_val(i), 118 DV_CHR, UID_UUCP, 119 GID_DIALER, 0600, 120 "tun%d", i); 121#endif 122 tunctl[i].tun_flags = TUN_INITED; 123 124 ifp = &tunctl[i].tun_if; 125 ifp->if_unit = i; 126 ifp->if_name = "tun"; 127 ifp->if_mtu = TUNMTU; 128 ifp->if_ioctl = tunifioctl; 129 ifp->if_output = tunoutput; 130 ifp->if_flags = IFF_POINTOPOINT | IFF_MULTICAST; 131 ifp->if_snd.ifq_maxlen = ifqmaxlen; 132 if_attach(ifp); 133#if NBPFILTER > 0 134 bpfattach(ifp, DLT_NULL, sizeof(u_int)); 135#endif 136 } 137} 138 139/* 140 * tunnel open - must be superuser & the device must be 141 * configured in 142 */ 143static int 144tunopen(dev, flag, mode, p) 145 dev_t dev; 146 int flag, mode; 147 struct proc *p; 148{ 149 struct ifnet *ifp; 150 struct tun_softc *tp; 151 register int unit, error; 152 153 error = suser(p->p_ucred, &p->p_acflag); 154 if (error) 155 return (error); 156 157 if ((unit = dev_val(minor(dev))) >= NTUN) 158 return (ENXIO); 159 tp = &tunctl[unit]; 160 if (tp->tun_flags & TUN_OPEN) 161 return EBUSY; 162 ifp = &tp->tun_if; 163 tp->tun_flags |= TUN_OPEN; 164 TUNDEBUG("%s%d: open\n", ifp->if_name, ifp->if_unit); 165 return (0); 166} 167 168/* 169 * tunclose - close the device - mark i/f down & delete 170 * routing info 171 */ 172static int 173tunclose(dev, foo, bar, p) 174 dev_t dev; 175 int foo; 176 int bar; 177 struct proc *p; 178{ 179 register int unit = dev_val(minor(dev)), s; 180 struct tun_softc *tp = &tunctl[unit]; 181 struct ifnet *ifp = &tp->tun_if; 182 struct mbuf *m; 183 184 tp->tun_flags &= ~TUN_OPEN; 185 186 /* 187 * junk all pending output 188 */ 189 do { 190 s = splimp(); 191 IF_DEQUEUE(&ifp->if_snd, m); 192 splx(s); 193 if (m) 194 m_freem(m); 195 } while (m); 196 197 if (ifp->if_flags & IFF_UP) { 198 s = splimp(); 199 if_down(ifp); 200 if (ifp->if_flags & IFF_RUNNING) { 201 /* find internet addresses and delete routes */ 202 register struct ifaddr *ifa; 203 for (ifa = ifp->if_addrhead.tqh_first; ifa; 204 ifa = ifa->ifa_link.tqe_next) { 205 if (ifa->ifa_addr->sa_family == AF_INET) { 206 rtinit(ifa, (int)RTM_DELETE, 207 tp->tun_flags & TUN_DSTADDR ? RTF_HOST : 0); 208 } 209 } 210 } 211 splx(s); 212 } 213 funsetown(tp->tun_sigio); 214 selwakeup(&tp->tun_rsel); 215 216 TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); 217 return (0); 218} 219 220static int 221tuninit(unit) 222 int unit; 223{ 224 struct tun_softc *tp = &tunctl[unit]; 225 struct ifnet *ifp = &tp->tun_if; 226 register struct ifaddr *ifa; 227 228 TUNDEBUG("%s%d: tuninit\n", ifp->if_name, ifp->if_unit); 229 230 ifp->if_flags |= IFF_UP | IFF_RUNNING; 231 getmicrotime(&ifp->if_lastchange); 232 233 for (ifa = ifp->if_addrhead.tqh_first; ifa; 234 ifa = ifa->ifa_link.tqe_next) { 235#ifdef INET 236 if (ifa->ifa_addr->sa_family == AF_INET) { 237 struct sockaddr_in *si; 238 239 si = (struct sockaddr_in *)ifa->ifa_addr; 240 if (si && si->sin_addr.s_addr) 241 tp->tun_flags |= TUN_IASET; 242 243 si = (struct sockaddr_in *)ifa->ifa_dstaddr; 244 if (si && si->sin_addr.s_addr) 245 tp->tun_flags |= TUN_DSTADDR; 246 } 247#endif 248 } 249 return 0; 250} 251 252/* 253 * Process an ioctl request. 254 */ 255int 256tunifioctl(ifp, cmd, data) 257 struct ifnet *ifp; 258 u_long cmd; 259 caddr_t data; 260{ 261 register struct ifreq *ifr = (struct ifreq *)data; 262 int error = 0, s; 263 264 s = splimp(); 265 switch(cmd) { 266 case SIOCSIFADDR: 267 tuninit(ifp->if_unit); 268 TUNDEBUG("%s%d: address set\n", 269 ifp->if_name, ifp->if_unit); 270 break; 271 case SIOCSIFDSTADDR: 272 tuninit(ifp->if_unit); 273 TUNDEBUG("%s%d: destination address set\n", 274 ifp->if_name, ifp->if_unit); 275 break; 276 case SIOCSIFMTU: 277 ifp->if_mtu = ifr->ifr_mtu; 278 TUNDEBUG("%s%d: mtu set\n", 279 ifp->if_name, ifp->if_unit); 280 break; 281 case SIOCADDMULTI: 282 case SIOCDELMULTI: 283 break; 284 285 286 default: 287 error = EINVAL; 288 } 289 splx(s); 290 return (error); 291} 292 293/* 294 * tunoutput - queue packets from higher level ready to put out. 295 */ 296int 297tunoutput(ifp, m0, dst, rt) 298 struct ifnet *ifp; 299 struct mbuf *m0; 300 struct sockaddr *dst; 301 struct rtentry *rt; 302{ 303 struct tun_softc *tp = &tunctl[ifp->if_unit]; 304 int s; 305 306 TUNDEBUG ("%s%d: tunoutput\n", ifp->if_name, ifp->if_unit); 307 308 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 309 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 310 ifp->if_unit, tp->tun_flags); 311 m_freem (m0); 312 return EHOSTDOWN; 313 } 314 315#if NBPFILTER > 0 316 /* BPF write needs to be handled specially */ 317 if (dst->sa_family == AF_UNSPEC) { 318 dst->sa_family = *(mtod(m0, int *)); 319 m0->m_len -= sizeof(int); 320 m0->m_pkthdr.len -= sizeof(int); 321 m0->m_data += sizeof(int); 322 } 323 324 if (ifp->if_bpf) { 325 /* 326 * We need to prepend the address family as 327 * a four byte field. Cons up a dummy header 328 * to pacify bpf. This is safe because bpf 329 * will only read from the mbuf (i.e., it won't 330 * try to free it or keep a pointer to it). 331 */ 332 struct mbuf m; 333 u_int af = dst->sa_family; 334 335 m.m_next = m0; 336 m.m_len = 4; 337 m.m_data = (char *)⁡ 338 339 bpf_mtap(ifp, &m); 340 } 341#endif 342 343 switch(dst->sa_family) { 344#ifdef INET 345 case AF_INET: 346 s = splimp(); 347 if (IF_QFULL(&ifp->if_snd)) { 348 IF_DROP(&ifp->if_snd); 349 m_freem(m0); 350 splx(s); 351 ifp->if_collisions++; 352 return (ENOBUFS); 353 } 354 ifp->if_obytes += m0->m_pkthdr.len; 355 IF_ENQUEUE(&ifp->if_snd, m0); 356 splx(s); 357 ifp->if_opackets++; 358 break; 359#endif 360 default: 361 m_freem(m0); 362 return EAFNOSUPPORT; 363 } 364 365 if (tp->tun_flags & TUN_RWAIT) { 366 tp->tun_flags &= ~TUN_RWAIT; 367 wakeup((caddr_t)tp); 368 } 369 if (tp->tun_flags & TUN_ASYNC && tp->tun_sigio) 370 pgsigio(tp->tun_sigio, SIGIO, 0); 371 selwakeup(&tp->tun_rsel); 372 return 0; 373} 374 375/* 376 * the cdevsw interface is now pretty minimal. 377 */ 378static int 379tunioctl(dev, cmd, data, flag, p) 380 dev_t dev; 381 u_long cmd; 382 caddr_t data; 383 int flag; 384 struct proc *p; 385{ 386 int unit = dev_val(minor(dev)), s; 387 struct tun_softc *tp = &tunctl[unit]; 388 struct tuninfo *tunp; 389 390 switch (cmd) { 391 case TUNSIFINFO: 392 tunp = (struct tuninfo *)data; 393 tp->tun_if.if_mtu = tunp->mtu; 394 tp->tun_if.if_type = tunp->type; 395 tp->tun_if.if_baudrate = tunp->baudrate; 396 break; 397 case TUNGIFINFO: 398 tunp = (struct tuninfo *)data; 399 tunp->mtu = tp->tun_if.if_mtu; 400 tunp->type = tp->tun_if.if_type; 401 tunp->baudrate = tp->tun_if.if_baudrate; 402 break; 403 case TUNSDEBUG: 404 tundebug = *(int *)data; 405 break; 406 case TUNGDEBUG: 407 *(int *)data = tundebug; 408 break; 409 case FIONBIO: 410 break; 411 case FIOASYNC: 412 if (*(int *)data) 413 tp->tun_flags |= TUN_ASYNC; 414 else 415 tp->tun_flags &= ~TUN_ASYNC; 416 break; 417 case FIONREAD: 418 s = splimp(); 419 if (tp->tun_if.if_snd.ifq_head) { 420 struct mbuf *mb = tp->tun_if.if_snd.ifq_head; 421 for( *(int *)data = 0; mb != 0; mb = mb->m_next) 422 *(int *)data += mb->m_len; 423 } else 424 *(int *)data = 0; 425 splx(s); 426 break; 427 case FIOSETOWN: 428 return (fsetown(*(int *)data, &tp->tun_sigio)); 429 430 case FIOGETOWN: 431 *(int *)data = fgetown(tp->tun_sigio); 432 return (0); 433 434 /* This is deprecated, FIOSETOWN should be used instead. */ 435 case TIOCSPGRP: 436 return (fsetown(-(*(int *)data), &tp->tun_sigio)); 437 438 /* This is deprecated, FIOGETOWN should be used instead. */ 439 case TIOCGPGRP: 440 *(int *)data = -fgetown(tp->tun_sigio); 441 return (0); 442 443 default: 444 return (ENOTTY); 445 } 446 return (0); 447} 448 449/* 450 * The cdevsw read interface - reads a packet at a time, or at 451 * least as much of a packet as can be read. 452 */ 453static int 454tunread(dev, uio, flag) 455 dev_t dev; 456 struct uio *uio; 457 int flag; 458{ 459 int unit = dev_val(minor(dev)); 460 struct tun_softc *tp = &tunctl[unit]; 461 struct ifnet *ifp = &tp->tun_if; 462 struct mbuf *m, *m0; 463 int error=0, len, s; 464 465 TUNDEBUG ("%s%d: read\n", ifp->if_name, ifp->if_unit); 466 if ((tp->tun_flags & TUN_READY) != TUN_READY) { 467 TUNDEBUG ("%s%d: not ready 0%o\n", ifp->if_name, 468 ifp->if_unit, tp->tun_flags); 469 return EHOSTDOWN; 470 } 471 472 tp->tun_flags &= ~TUN_RWAIT; 473 474 s = splimp(); 475 do { 476 IF_DEQUEUE(&ifp->if_snd, m0); 477 if (m0 == 0) { 478 if (flag & IO_NDELAY) { 479 splx(s); 480 return EWOULDBLOCK; 481 } 482 tp->tun_flags |= TUN_RWAIT; 483 if( error = tsleep((caddr_t)tp, PCATCH | (PZERO + 1), 484 "tunread", 0)) { 485 splx(s); 486 return error; 487 } 488 } 489 } while (m0 == 0); 490 splx(s); 491 492 while (m0 && uio->uio_resid > 0 && error == 0) { 493 len = min(uio->uio_resid, m0->m_len); 494 if (len == 0) 495 break; 496 error = uiomove(mtod(m0, caddr_t), len, uio); 497 MFREE(m0, m); 498 m0 = m; 499 } 500 501 if (m0) { 502 TUNDEBUG("Dropping mbuf\n"); 503 m_freem(m0); 504 } 505 return error; 506} 507 508/* 509 * the cdevsw write interface - an atomic write is a packet - or else! 510 */ 511static int 512tunwrite(dev, uio, flag) 513 dev_t dev; 514 struct uio *uio; 515 int flag; 516{ 517 int unit = dev_val(minor(dev)); 518 struct ifnet *ifp = &tunctl[unit].tun_if; 519 struct mbuf *top, **mp, *m; 520 int error=0, s, tlen, mlen; 521 522 TUNDEBUG("%s%d: tunwrite\n", ifp->if_name, ifp->if_unit); 523 524 if (uio->uio_resid < 0 || uio->uio_resid > TUNMRU) { 525 TUNDEBUG("%s%d: len=%d!\n", ifp->if_name, ifp->if_unit, 526 uio->uio_resid); 527 return EIO; 528 } 529 tlen = uio->uio_resid; 530 531 /* get a header mbuf */ 532 MGETHDR(m, M_DONTWAIT, MT_DATA); 533 if (m == NULL) 534 return ENOBUFS; 535 mlen = MHLEN; 536 537 top = 0; 538 mp = ⊤ 539 while (error == 0 && uio->uio_resid > 0) { 540 m->m_len = min(mlen, uio->uio_resid); 541 error = uiomove(mtod (m, caddr_t), m->m_len, uio); 542 *mp = m; 543 mp = &m->m_next; 544 if (uio->uio_resid > 0) { 545 MGET (m, M_DONTWAIT, MT_DATA); 546 if (m == 0) { 547 error = ENOBUFS; 548 break; 549 } 550 mlen = MLEN; 551 } 552 } 553 if (error) { 554 if (top) 555 m_freem (top); 556 return error; 557 } 558 559 top->m_pkthdr.len = tlen; 560 top->m_pkthdr.rcvif = ifp; 561 562#if NBPFILTER > 0 563 if (ifp->if_bpf) { 564 /* 565 * We need to prepend the address family as 566 * a four byte field. Cons up a dummy header 567 * to pacify bpf. This is safe because bpf 568 * will only read from the mbuf (i.e., it won't 569 * try to free it or keep a pointer to it). 570 */ 571 struct mbuf m; 572 u_int af = AF_INET; 573 574 m.m_next = top; 575 m.m_len = 4; 576 m.m_data = (char *)⁡ 577 578 bpf_mtap(ifp, &m); 579 } 580#endif 581 582#ifdef INET 583 s = splimp(); 584 if (IF_QFULL (&ipintrq)) { 585 IF_DROP(&ipintrq); 586 splx(s); 587 ifp->if_collisions++; 588 m_freem(top); 589 return ENOBUFS; 590 } 591 IF_ENQUEUE(&ipintrq, top); 592 splx(s); 593 ifp->if_ibytes += tlen; 594 ifp->if_ipackets++; 595 schednetisr(NETISR_IP); 596#endif 597 return error; 598} 599 600/* 601 * tunpoll - the poll interface, this is only useful on reads 602 * really. The write detect always returns true, write never blocks 603 * anyway, it either accepts the packet or drops it. 604 */ 605static int 606tunpoll(dev, events, p) 607 dev_t dev; 608 int events; 609 struct proc *p; 610{ 611 int unit = dev_val(minor(dev)), s; 612 struct tun_softc *tp = &tunctl[unit]; 613 struct ifnet *ifp = &tp->tun_if; 614 int revents = 0; 615 616 s = splimp(); 617 TUNDEBUG("%s%d: tunpoll\n", ifp->if_name, ifp->if_unit); 618 619 if (events & (POLLIN | POLLRDNORM)) 620 if (ifp->if_snd.ifq_len > 0) { 621 TUNDEBUG("%s%d: tunpoll q=%d\n", ifp->if_name, 622 ifp->if_unit, ifp->if_snd.ifq_len); 623 revents |= events & (POLLIN | POLLRDNORM); 624 } else { 625 TUNDEBUG("%s%d: tunpoll waiting\n", ifp->if_name, 626 ifp->if_unit); 627 selrecord(p, &tp->tun_rsel); 628 } 629 630 if (events & (POLLOUT | POLLWRNORM)) 631 revents |= events & (POLLOUT | POLLWRNORM); 632 633 splx(s); 634 return (revents); 635} 636 637 638#endif /* NTUN */ 639