1 /* $NetBSD: if_tap.c,v 1.106 2018/06/26 06:48:02 msaitoh Exp $ */ 2 3 /* 4 * Copyright (c) 2003, 2004, 2008, 2009 The NetBSD Foundation. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /* 30 * tap(4) is a virtual Ethernet interface. It appears as a real Ethernet 31 * device to the system, but can also be accessed by userland through a 32 * character device interface, which allows reading and injecting frames. 33 */ 34 35 #include <sys/cdefs.h> 36 __KERNEL_RCSID(0, "$NetBSD: if_tap.c,v 1.106 2018/06/26 06:48:02 msaitoh Exp $"); 37 38 #if defined(_KERNEL_OPT) 39 40 #include "opt_modular.h" 41 #include "opt_compat_netbsd.h" 42 #endif 43 44 #include <sys/param.h> 45 #include <sys/atomic.h> 46 #include <sys/conf.h> 47 #include <sys/cprng.h> 48 #include <sys/device.h> 49 #include <sys/file.h> 50 #include <sys/filedesc.h> 51 #include <sys/intr.h> 52 #include <sys/kauth.h> 53 #include <sys/kernel.h> 54 #include <sys/kmem.h> 55 #include <sys/module.h> 56 #include <sys/mutex.h> 57 #include <sys/condvar.h> 58 #include <sys/poll.h> 59 #include <sys/proc.h> 60 #include <sys/select.h> 61 #include <sys/sockio.h> 62 #include <sys/stat.h> 63 #include <sys/sysctl.h> 64 #include <sys/systm.h> 65 66 #include <net/if.h> 67 #include <net/if_dl.h> 68 #include <net/if_ether.h> 69 #include <net/if_media.h> 70 #include <net/if_tap.h> 71 #include <net/bpf.h> 72 73 #include <compat/sys/sockio.h> 74 75 #include "ioconf.h" 76 77 /* 78 * sysctl node management 79 * 80 * It's not really possible to use a SYSCTL_SETUP block with 81 * current module implementation, so it is easier to just define 82 * our own function. 83 * 84 * The handler function is a "helper" in Andrew Brown's sysctl 85 * framework terminology. It is used as a gateway for sysctl 86 * requests over the nodes. 87 * 88 * tap_log allows the module to log creations of nodes and 89 * destroy them all at once using sysctl_teardown. 90 */ 91 static int tap_node; 92 static int tap_sysctl_handler(SYSCTLFN_PROTO); 93 static void sysctl_tap_setup(struct sysctllog **); 94 95 /* 96 * Since we're an Ethernet device, we need the 2 following 97 * components: a struct ethercom and a struct ifmedia 98 * since we don't attach a PHY to ourselves. 99 * We could emulate one, but there's no real point. 100 */ 101 102 struct tap_softc { 103 device_t sc_dev; 104 struct ifmedia sc_im; 105 struct ethercom sc_ec; 106 int sc_flags; 107 #define TAP_INUSE 0x00000001 /* tap device can only be opened once */ 108 #define TAP_ASYNCIO 0x00000002 /* user is using async I/O (SIGIO) on the device */ 109 #define TAP_NBIO 0x00000004 /* user wants calls to avoid blocking */ 110 #define TAP_GOING 0x00000008 /* interface is being destroyed */ 111 struct selinfo sc_rsel; 112 pid_t sc_pgid; /* For async. IO */ 113 kmutex_t sc_lock; 114 kcondvar_t sc_cv; 115 void *sc_sih; 116 struct timespec sc_atime; 117 struct timespec sc_mtime; 118 struct timespec sc_btime; 119 }; 120 121 /* autoconf(9) glue */ 122 123 static int tap_match(device_t, cfdata_t, void *); 124 static void tap_attach(device_t, device_t, void *); 125 static int tap_detach(device_t, int); 126 127 CFATTACH_DECL_NEW(tap, sizeof(struct tap_softc), 128 tap_match, tap_attach, tap_detach, NULL); 129 extern struct cfdriver tap_cd; 130 131 /* Real device access routines */ 132 static int tap_dev_close(struct tap_softc *); 133 static int tap_dev_read(int, struct uio *, int); 134 static int tap_dev_write(int, struct uio *, int); 135 static int tap_dev_ioctl(int, u_long, void *, struct lwp *); 136 static int tap_dev_poll(int, int, struct lwp *); 137 static int tap_dev_kqfilter(int, struct knote *); 138 139 /* Fileops access routines */ 140 static int tap_fops_close(file_t *); 141 static int tap_fops_read(file_t *, off_t *, struct uio *, 142 kauth_cred_t, int); 143 static int tap_fops_write(file_t *, off_t *, struct uio *, 144 kauth_cred_t, int); 145 static int tap_fops_ioctl(file_t *, u_long, void *); 146 static int tap_fops_poll(file_t *, int); 147 static int tap_fops_stat(file_t *, struct stat *); 148 static int tap_fops_kqfilter(file_t *, struct knote *); 149 150 static const struct fileops tap_fileops = { 151 .fo_name = "tap", 152 .fo_read = tap_fops_read, 153 .fo_write = tap_fops_write, 154 .fo_ioctl = tap_fops_ioctl, 155 .fo_fcntl = fnullop_fcntl, 156 .fo_poll = tap_fops_poll, 157 .fo_stat = tap_fops_stat, 158 .fo_close = tap_fops_close, 159 .fo_kqfilter = tap_fops_kqfilter, 160 .fo_restart = fnullop_restart, 161 }; 162 163 /* Helper for cloning open() */ 164 static int tap_dev_cloner(struct lwp *); 165 166 /* Character device routines */ 167 static int tap_cdev_open(dev_t, int, int, struct lwp *); 168 static int tap_cdev_close(dev_t, int, int, struct lwp *); 169 static int tap_cdev_read(dev_t, struct uio *, int); 170 static int tap_cdev_write(dev_t, struct uio *, int); 171 static int tap_cdev_ioctl(dev_t, u_long, void *, int, struct lwp *); 172 static int tap_cdev_poll(dev_t, int, struct lwp *); 173 static int tap_cdev_kqfilter(dev_t, struct knote *); 174 175 const struct cdevsw tap_cdevsw = { 176 .d_open = tap_cdev_open, 177 .d_close = tap_cdev_close, 178 .d_read = tap_cdev_read, 179 .d_write = tap_cdev_write, 180 .d_ioctl = tap_cdev_ioctl, 181 .d_stop = nostop, 182 .d_tty = notty, 183 .d_poll = tap_cdev_poll, 184 .d_mmap = nommap, 185 .d_kqfilter = tap_cdev_kqfilter, 186 .d_discard = nodiscard, 187 .d_flag = D_OTHER | D_MPSAFE 188 }; 189 190 #define TAP_CLONER 0xfffff /* Maximal minor value */ 191 192 /* kqueue-related routines */ 193 static void tap_kqdetach(struct knote *); 194 static int tap_kqread(struct knote *, long); 195 196 /* 197 * Those are needed by the if_media interface. 198 */ 199 200 static int tap_mediachange(struct ifnet *); 201 static void tap_mediastatus(struct ifnet *, struct ifmediareq *); 202 203 /* 204 * Those are needed by the ifnet interface, and would typically be 205 * there for any network interface driver. 206 * Some other routines are optional: watchdog and drain. 207 */ 208 209 static void tap_start(struct ifnet *); 210 static void tap_stop(struct ifnet *, int); 211 static int tap_init(struct ifnet *); 212 static int tap_ioctl(struct ifnet *, u_long, void *); 213 214 /* Internal functions */ 215 static int tap_lifaddr(struct ifnet *, u_long, struct ifaliasreq *); 216 static void tap_softintr(void *); 217 218 /* 219 * tap is a clonable interface, although it is highly unrealistic for 220 * an Ethernet device. 221 * 222 * Here are the bits needed for a clonable interface. 223 */ 224 static int tap_clone_create(struct if_clone *, int); 225 static int tap_clone_destroy(struct ifnet *); 226 227 struct if_clone tap_cloners = IF_CLONE_INITIALIZER("tap", 228 tap_clone_create, 229 tap_clone_destroy); 230 231 /* Helper functions shared by the two cloning code paths */ 232 static struct tap_softc * tap_clone_creator(int); 233 int tap_clone_destroyer(device_t); 234 235 static struct sysctllog *tap_sysctl_clog; 236 237 #ifdef _MODULE 238 devmajor_t tap_bmajor = -1, tap_cmajor = -1; 239 #endif 240 241 static u_int tap_count; 242 243 void 244 tapattach(int n) 245 { 246 247 /* 248 * Nothing to do here, initialization is handled by the 249 * module initialization code in tapinit() below). 250 */ 251 } 252 253 static void 254 tapinit(void) 255 { 256 int error = config_cfattach_attach(tap_cd.cd_name, &tap_ca); 257 if (error) { 258 aprint_error("%s: unable to register cfattach\n", 259 tap_cd.cd_name); 260 (void)config_cfdriver_detach(&tap_cd); 261 return; 262 } 263 264 if_clone_attach(&tap_cloners); 265 sysctl_tap_setup(&tap_sysctl_clog); 266 #ifdef _MODULE 267 devsw_attach("tap", NULL, &tap_bmajor, &tap_cdevsw, &tap_cmajor); 268 #endif 269 } 270 271 static int 272 tapdetach(void) 273 { 274 int error = 0; 275 276 if (tap_count != 0) 277 return EBUSY; 278 279 #ifdef _MODULE 280 if (error == 0) 281 error = devsw_detach(NULL, &tap_cdevsw); 282 #endif 283 if (error == 0) 284 sysctl_teardown(&tap_sysctl_clog); 285 if (error == 0) 286 if_clone_detach(&tap_cloners); 287 288 if (error == 0) 289 error = config_cfattach_detach(tap_cd.cd_name, &tap_ca); 290 291 return error; 292 } 293 294 /* Pretty much useless for a pseudo-device */ 295 static int 296 tap_match(device_t parent, cfdata_t cfdata, void *arg) 297 { 298 299 return 1; 300 } 301 302 void 303 tap_attach(device_t parent, device_t self, void *aux) 304 { 305 struct tap_softc *sc = device_private(self); 306 struct ifnet *ifp; 307 const struct sysctlnode *node; 308 int error; 309 uint8_t enaddr[ETHER_ADDR_LEN] = 310 { 0xf2, 0x0b, 0xa4, 0xff, 0xff, 0xff }; 311 char enaddrstr[3 * ETHER_ADDR_LEN]; 312 313 sc->sc_dev = self; 314 sc->sc_sih = NULL; 315 getnanotime(&sc->sc_btime); 316 sc->sc_atime = sc->sc_mtime = sc->sc_btime; 317 sc->sc_flags = 0; 318 selinit(&sc->sc_rsel); 319 320 cv_init(&sc->sc_cv, "tapread"); 321 mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NET); 322 323 if (!pmf_device_register(self, NULL, NULL)) 324 aprint_error_dev(self, "couldn't establish power handler\n"); 325 326 /* 327 * In order to obtain unique initial Ethernet address on a host, 328 * do some randomisation. It's not meant for anything but avoiding 329 * hard-coding an address. 330 */ 331 cprng_fast(&enaddr[3], 3); 332 333 aprint_verbose_dev(self, "Ethernet address %s\n", 334 ether_snprintf(enaddrstr, sizeof(enaddrstr), enaddr)); 335 336 /* 337 * Why 1000baseT? Why not? You can add more. 338 * 339 * Note that there are 3 steps: init, one or several additions to 340 * list of supported media, and in the end, the selection of one 341 * of them. 342 */ 343 ifmedia_init(&sc->sc_im, 0, tap_mediachange, tap_mediastatus); 344 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T, 0, NULL); 345 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T|IFM_FDX, 0, NULL); 346 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX, 0, NULL); 347 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX|IFM_FDX, 0, NULL); 348 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T, 0, NULL); 349 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T|IFM_FDX, 0, NULL); 350 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_AUTO, 0, NULL); 351 ifmedia_set(&sc->sc_im, IFM_ETHER|IFM_AUTO); 352 353 /* 354 * One should note that an interface must do multicast in order 355 * to support IPv6. 356 */ 357 ifp = &sc->sc_ec.ec_if; 358 strcpy(ifp->if_xname, device_xname(self)); 359 ifp->if_softc = sc; 360 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 361 ifp->if_extflags = IFEF_NO_LINK_STATE_CHANGE; 362 #ifdef NET_MPSAFE 363 ifp->if_extflags |= IFEF_MPSAFE; 364 #endif 365 ifp->if_ioctl = tap_ioctl; 366 ifp->if_start = tap_start; 367 ifp->if_stop = tap_stop; 368 ifp->if_init = tap_init; 369 IFQ_SET_READY(&ifp->if_snd); 370 371 sc->sc_ec.ec_capabilities = ETHERCAP_VLAN_MTU | ETHERCAP_JUMBO_MTU; 372 373 /* Those steps are mandatory for an Ethernet driver. */ 374 error = if_initialize(ifp); 375 if (error != 0) { 376 aprint_error_dev(self, "if_initialize failed(%d)\n", error); 377 ifmedia_removeall(&sc->sc_im); 378 pmf_device_deregister(self); 379 mutex_destroy(&sc->sc_lock); 380 seldestroy(&sc->sc_rsel); 381 382 return; /* Error */ 383 } 384 ifp->if_percpuq = if_percpuq_create(ifp); 385 ether_ifattach(ifp, enaddr); 386 if_register(ifp); 387 388 /* 389 * Add a sysctl node for that interface. 390 * 391 * The pointer transmitted is not a string, but instead a pointer to 392 * the softc structure, which we can use to build the string value on 393 * the fly in the helper function of the node. See the comments for 394 * tap_sysctl_handler for details. 395 * 396 * Usually sysctl_createv is called with CTL_CREATE as the before-last 397 * component. However, we can allocate a number ourselves, as we are 398 * the only consumer of the net.link.<iface> node. In this case, the 399 * unit number is conveniently used to number the node. CTL_CREATE 400 * would just work, too. 401 */ 402 if ((error = sysctl_createv(NULL, 0, NULL, 403 &node, CTLFLAG_READWRITE, 404 CTLTYPE_STRING, device_xname(self), NULL, 405 tap_sysctl_handler, 0, (void *)sc, 18, 406 CTL_NET, AF_LINK, tap_node, device_unit(sc->sc_dev), 407 CTL_EOL)) != 0) 408 aprint_error_dev(self, 409 "sysctl_createv returned %d, ignoring\n", error); 410 } 411 412 /* 413 * When detaching, we do the inverse of what is done in the attach 414 * routine, in reversed order. 415 */ 416 static int 417 tap_detach(device_t self, int flags) 418 { 419 struct tap_softc *sc = device_private(self); 420 struct ifnet *ifp = &sc->sc_ec.ec_if; 421 int error; 422 423 sc->sc_flags |= TAP_GOING; 424 tap_stop(ifp, 1); 425 if_down(ifp); 426 427 if (sc->sc_sih != NULL) { 428 softint_disestablish(sc->sc_sih); 429 sc->sc_sih = NULL; 430 } 431 432 /* 433 * Destroying a single leaf is a very straightforward operation using 434 * sysctl_destroyv. One should be sure to always end the path with 435 * CTL_EOL. 436 */ 437 if ((error = sysctl_destroyv(NULL, CTL_NET, AF_LINK, tap_node, 438 device_unit(sc->sc_dev), CTL_EOL)) != 0) 439 aprint_error_dev(self, 440 "sysctl_destroyv returned %d, ignoring\n", error); 441 ether_ifdetach(ifp); 442 if_detach(ifp); 443 ifmedia_removeall(&sc->sc_im); 444 seldestroy(&sc->sc_rsel); 445 mutex_destroy(&sc->sc_lock); 446 cv_destroy(&sc->sc_cv); 447 448 pmf_device_deregister(self); 449 450 return 0; 451 } 452 453 /* 454 * This function is called by the ifmedia layer to notify the driver 455 * that the user requested a media change. A real driver would 456 * reconfigure the hardware. 457 */ 458 static int 459 tap_mediachange(struct ifnet *ifp) 460 { 461 return 0; 462 } 463 464 /* 465 * Here the user asks for the currently used media. 466 */ 467 static void 468 tap_mediastatus(struct ifnet *ifp, struct ifmediareq *imr) 469 { 470 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 471 imr->ifm_active = sc->sc_im.ifm_cur->ifm_media; 472 } 473 474 /* 475 * This is the function where we SEND packets. 476 * 477 * There is no 'receive' equivalent. A typical driver will get 478 * interrupts from the hardware, and from there will inject new packets 479 * into the network stack. 480 * 481 * Once handled, a packet must be freed. A real driver might not be able 482 * to fit all the pending packets into the hardware, and is allowed to 483 * return before having sent all the packets. It should then use the 484 * if_flags flag IFF_OACTIVE to notify the upper layer. 485 * 486 * There are also other flags one should check, such as IFF_PAUSE. 487 * 488 * It is our duty to make packets available to BPF listeners. 489 * 490 * You should be aware that this function is called by the Ethernet layer 491 * at splnet(). 492 * 493 * When the device is opened, we have to pass the packet(s) to the 494 * userland. For that we stay in OACTIVE mode while the userland gets 495 * the packets, and we send a signal to the processes waiting to read. 496 * 497 * wakeup(sc) is the counterpart to the tsleep call in 498 * tap_dev_read, while selnotify() is used for kevent(2) and 499 * poll(2) (which includes select(2)) listeners. 500 */ 501 static void 502 tap_start(struct ifnet *ifp) 503 { 504 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 505 struct mbuf *m0; 506 507 mutex_enter(&sc->sc_lock); 508 if ((sc->sc_flags & TAP_INUSE) == 0) { 509 /* Simply drop packets */ 510 for(;;) { 511 IFQ_DEQUEUE(&ifp->if_snd, m0); 512 if (m0 == NULL) 513 goto done; 514 515 ifp->if_opackets++; 516 bpf_mtap(ifp, m0, BPF_D_OUT); 517 518 m_freem(m0); 519 } 520 } else if (!IFQ_IS_EMPTY(&ifp->if_snd)) { 521 ifp->if_flags |= IFF_OACTIVE; 522 cv_broadcast(&sc->sc_cv); 523 selnotify(&sc->sc_rsel, 0, 1); 524 if (sc->sc_flags & TAP_ASYNCIO) 525 softint_schedule(sc->sc_sih); 526 } 527 done: 528 mutex_exit(&sc->sc_lock); 529 } 530 531 static void 532 tap_softintr(void *cookie) 533 { 534 struct tap_softc *sc; 535 struct ifnet *ifp; 536 int a, b; 537 538 sc = cookie; 539 540 if (sc->sc_flags & TAP_ASYNCIO) { 541 ifp = &sc->sc_ec.ec_if; 542 if (ifp->if_flags & IFF_RUNNING) { 543 a = POLL_IN; 544 b = POLLIN|POLLRDNORM; 545 } else { 546 a = POLL_HUP; 547 b = 0; 548 } 549 fownsignal(sc->sc_pgid, SIGIO, a, b, NULL); 550 } 551 } 552 553 /* 554 * A typical driver will only contain the following handlers for 555 * ioctl calls, except SIOCSIFPHYADDR. 556 * The latter is a hack I used to set the Ethernet address of the 557 * faked device. 558 * 559 * Note that both ifmedia_ioctl() and ether_ioctl() have to be 560 * called under splnet(). 561 */ 562 static int 563 tap_ioctl(struct ifnet *ifp, u_long cmd, void *data) 564 { 565 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 566 struct ifreq *ifr = (struct ifreq *)data; 567 int s, error; 568 569 s = splnet(); 570 571 switch (cmd) { 572 #ifdef OSIOCSIFMEDIA 573 case OSIOCSIFMEDIA: 574 #endif 575 case SIOCSIFMEDIA: 576 case SIOCGIFMEDIA: 577 error = ifmedia_ioctl(ifp, ifr, &sc->sc_im, cmd); 578 break; 579 case SIOCSIFPHYADDR: 580 error = tap_lifaddr(ifp, cmd, (struct ifaliasreq *)data); 581 break; 582 default: 583 error = ether_ioctl(ifp, cmd, data); 584 if (error == ENETRESET) 585 error = 0; 586 break; 587 } 588 589 splx(s); 590 591 return error; 592 } 593 594 /* 595 * Helper function to set Ethernet address. This has been replaced by 596 * the generic SIOCALIFADDR ioctl on a PF_LINK socket. 597 */ 598 static int 599 tap_lifaddr(struct ifnet *ifp, u_long cmd, struct ifaliasreq *ifra) 600 { 601 const struct sockaddr *sa = &ifra->ifra_addr; 602 603 if (sa->sa_family != AF_LINK) 604 return EINVAL; 605 606 if_set_sadl(ifp, sa->sa_data, ETHER_ADDR_LEN, false); 607 608 return 0; 609 } 610 611 /* 612 * _init() would typically be called when an interface goes up, 613 * meaning it should configure itself into the state in which it 614 * can send packets. 615 */ 616 static int 617 tap_init(struct ifnet *ifp) 618 { 619 ifp->if_flags |= IFF_RUNNING; 620 621 tap_start(ifp); 622 623 return 0; 624 } 625 626 /* 627 * _stop() is called when an interface goes down. It is our 628 * responsability to validate that state by clearing the 629 * IFF_RUNNING flag. 630 * 631 * We have to wake up all the sleeping processes to have the pending 632 * read requests cancelled. 633 */ 634 static void 635 tap_stop(struct ifnet *ifp, int disable) 636 { 637 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 638 639 mutex_enter(&sc->sc_lock); 640 ifp->if_flags &= ~IFF_RUNNING; 641 cv_broadcast(&sc->sc_cv); 642 selnotify(&sc->sc_rsel, 0, 1); 643 if (sc->sc_flags & TAP_ASYNCIO) 644 softint_schedule(sc->sc_sih); 645 mutex_exit(&sc->sc_lock); 646 } 647 648 /* 649 * The 'create' command of ifconfig can be used to create 650 * any numbered instance of a given device. Thus we have to 651 * make sure we have enough room in cd_devs to create the 652 * user-specified instance. config_attach_pseudo will do this 653 * for us. 654 */ 655 static int 656 tap_clone_create(struct if_clone *ifc, int unit) 657 { 658 if (tap_clone_creator(unit) == NULL) { 659 aprint_error("%s%d: unable to attach an instance\n", 660 tap_cd.cd_name, unit); 661 return ENXIO; 662 } 663 atomic_inc_uint(&tap_count); 664 return 0; 665 } 666 667 /* 668 * tap(4) can be cloned by two ways: 669 * using 'ifconfig tap0 create', which will use the network 670 * interface cloning API, and call tap_clone_create above. 671 * opening the cloning device node, whose minor number is TAP_CLONER. 672 * See below for an explanation on how this part work. 673 */ 674 static struct tap_softc * 675 tap_clone_creator(int unit) 676 { 677 cfdata_t cf; 678 679 cf = kmem_alloc(sizeof(*cf), KM_SLEEP); 680 cf->cf_name = tap_cd.cd_name; 681 cf->cf_atname = tap_ca.ca_name; 682 if (unit == -1) { 683 /* let autoconf find the first free one */ 684 cf->cf_unit = 0; 685 cf->cf_fstate = FSTATE_STAR; 686 } else { 687 cf->cf_unit = unit; 688 cf->cf_fstate = FSTATE_NOTFOUND; 689 } 690 691 return device_private(config_attach_pseudo(cf)); 692 } 693 694 /* 695 * The clean design of if_clone and autoconf(9) makes that part 696 * really straightforward. The second argument of config_detach 697 * means neither QUIET nor FORCED. 698 */ 699 static int 700 tap_clone_destroy(struct ifnet *ifp) 701 { 702 struct tap_softc *sc = ifp->if_softc; 703 int error = tap_clone_destroyer(sc->sc_dev); 704 705 if (error == 0) 706 atomic_dec_uint(&tap_count); 707 return error; 708 } 709 710 int 711 tap_clone_destroyer(device_t dev) 712 { 713 cfdata_t cf = device_cfdata(dev); 714 int error; 715 716 if ((error = config_detach(dev, 0)) != 0) 717 aprint_error_dev(dev, "unable to detach instance\n"); 718 kmem_free(cf, sizeof(*cf)); 719 720 return error; 721 } 722 723 /* 724 * tap(4) is a bit of an hybrid device. It can be used in two different 725 * ways: 726 * 1. ifconfig tapN create, then use /dev/tapN to read/write off it. 727 * 2. open /dev/tap, get a new interface created and read/write off it. 728 * That interface is destroyed when the process that had it created exits. 729 * 730 * The first way is managed by the cdevsw structure, and you access interfaces 731 * through a (major, minor) mapping: tap4 is obtained by the minor number 732 * 4. The entry points for the cdevsw interface are prefixed by tap_cdev_. 733 * 734 * The second way is the so-called "cloning" device. It's a special minor 735 * number (chosen as the maximal number, to allow as much tap devices as 736 * possible). The user first opens the cloner (e.g., /dev/tap), and that 737 * call ends in tap_cdev_open. The actual place where it is handled is 738 * tap_dev_cloner. 739 * 740 * An tap device cannot be opened more than once at a time, so the cdevsw 741 * part of open() does nothing but noting that the interface is being used and 742 * hence ready to actually handle packets. 743 */ 744 745 static int 746 tap_cdev_open(dev_t dev, int flags, int fmt, struct lwp *l) 747 { 748 struct tap_softc *sc; 749 750 if (minor(dev) == TAP_CLONER) 751 return tap_dev_cloner(l); 752 753 sc = device_lookup_private(&tap_cd, minor(dev)); 754 if (sc == NULL) 755 return ENXIO; 756 757 /* The device can only be opened once */ 758 if (sc->sc_flags & TAP_INUSE) 759 return EBUSY; 760 sc->sc_flags |= TAP_INUSE; 761 return 0; 762 } 763 764 /* 765 * There are several kinds of cloning devices, and the most simple is the one 766 * tap(4) uses. What it does is change the file descriptor with a new one, 767 * with its own fileops structure (which maps to the various read, write, 768 * ioctl functions). It starts allocating a new file descriptor with falloc, 769 * then actually creates the new tap devices. 770 * 771 * Once those two steps are successful, we can re-wire the existing file 772 * descriptor to its new self. This is done with fdclone(): it fills the fp 773 * structure as needed (notably f_devunit gets filled with the fifth parameter 774 * passed, the unit of the tap device which will allows us identifying the 775 * device later), and returns EMOVEFD. 776 * 777 * That magic value is interpreted by sys_open() which then replaces the 778 * current file descriptor by the new one (through a magic member of struct 779 * lwp, l_dupfd). 780 * 781 * The tap device is flagged as being busy since it otherwise could be 782 * externally accessed through the corresponding device node with the cdevsw 783 * interface. 784 */ 785 786 static int 787 tap_dev_cloner(struct lwp *l) 788 { 789 struct tap_softc *sc; 790 file_t *fp; 791 int error, fd; 792 793 if ((error = fd_allocfile(&fp, &fd)) != 0) 794 return error; 795 796 if ((sc = tap_clone_creator(-1)) == NULL) { 797 fd_abort(curproc, fp, fd); 798 return ENXIO; 799 } 800 801 sc->sc_flags |= TAP_INUSE; 802 803 return fd_clone(fp, fd, FREAD|FWRITE, &tap_fileops, 804 (void *)(intptr_t)device_unit(sc->sc_dev)); 805 } 806 807 /* 808 * While all other operations (read, write, ioctl, poll and kqfilter) are 809 * really the same whether we are in cdevsw or fileops mode, the close() 810 * function is slightly different in the two cases. 811 * 812 * As for the other, the core of it is shared in tap_dev_close. What 813 * it does is sufficient for the cdevsw interface, but the cloning interface 814 * needs another thing: the interface is destroyed when the processes that 815 * created it closes it. 816 */ 817 static int 818 tap_cdev_close(dev_t dev, int flags, int fmt, 819 struct lwp *l) 820 { 821 struct tap_softc *sc = 822 device_lookup_private(&tap_cd, minor(dev)); 823 824 if (sc == NULL) 825 return ENXIO; 826 827 return tap_dev_close(sc); 828 } 829 830 /* 831 * It might happen that the administrator used ifconfig to externally destroy 832 * the interface. In that case, tap_fops_close will be called while 833 * tap_detach is already happening. If we called it again from here, we 834 * would dead lock. TAP_GOING ensures that this situation doesn't happen. 835 */ 836 static int 837 tap_fops_close(file_t *fp) 838 { 839 int unit = fp->f_devunit; 840 struct tap_softc *sc; 841 int error; 842 843 sc = device_lookup_private(&tap_cd, unit); 844 if (sc == NULL) 845 return ENXIO; 846 847 /* tap_dev_close currently always succeeds, but it might not 848 * always be the case. */ 849 KERNEL_LOCK(1, NULL); 850 if ((error = tap_dev_close(sc)) != 0) { 851 KERNEL_UNLOCK_ONE(NULL); 852 return error; 853 } 854 855 /* Destroy the device now that it is no longer useful, 856 * unless it's already being destroyed. */ 857 if ((sc->sc_flags & TAP_GOING) != 0) { 858 KERNEL_UNLOCK_ONE(NULL); 859 return 0; 860 } 861 862 error = tap_clone_destroyer(sc->sc_dev); 863 KERNEL_UNLOCK_ONE(NULL); 864 return error; 865 } 866 867 static int 868 tap_dev_close(struct tap_softc *sc) 869 { 870 struct ifnet *ifp; 871 int s; 872 873 s = splnet(); 874 /* Let tap_start handle packets again */ 875 ifp = &sc->sc_ec.ec_if; 876 ifp->if_flags &= ~IFF_OACTIVE; 877 878 /* Purge output queue */ 879 if (!(IFQ_IS_EMPTY(&ifp->if_snd))) { 880 struct mbuf *m; 881 882 for (;;) { 883 IFQ_DEQUEUE(&ifp->if_snd, m); 884 if (m == NULL) 885 break; 886 887 ifp->if_opackets++; 888 bpf_mtap(ifp, m, BPF_D_OUT); 889 m_freem(m); 890 } 891 } 892 splx(s); 893 894 if (sc->sc_sih != NULL) { 895 softint_disestablish(sc->sc_sih); 896 sc->sc_sih = NULL; 897 } 898 sc->sc_flags &= ~(TAP_INUSE | TAP_ASYNCIO); 899 900 return 0; 901 } 902 903 static int 904 tap_cdev_read(dev_t dev, struct uio *uio, int flags) 905 { 906 return tap_dev_read(minor(dev), uio, flags); 907 } 908 909 static int 910 tap_fops_read(file_t *fp, off_t *offp, struct uio *uio, 911 kauth_cred_t cred, int flags) 912 { 913 int error; 914 915 KERNEL_LOCK(1, NULL); 916 error = tap_dev_read(fp->f_devunit, uio, flags); 917 KERNEL_UNLOCK_ONE(NULL); 918 return error; 919 } 920 921 static int 922 tap_dev_read(int unit, struct uio *uio, int flags) 923 { 924 struct tap_softc *sc = device_lookup_private(&tap_cd, unit); 925 struct ifnet *ifp; 926 struct mbuf *m, *n; 927 int error = 0; 928 929 if (sc == NULL) 930 return ENXIO; 931 932 getnanotime(&sc->sc_atime); 933 934 ifp = &sc->sc_ec.ec_if; 935 if ((ifp->if_flags & IFF_UP) == 0) 936 return EHOSTDOWN; 937 938 /* 939 * In the TAP_NBIO case, we have to make sure we won't be sleeping 940 */ 941 if ((sc->sc_flags & TAP_NBIO) != 0) { 942 if (!mutex_tryenter(&sc->sc_lock)) 943 return EWOULDBLOCK; 944 } else { 945 mutex_enter(&sc->sc_lock); 946 } 947 948 if (IFQ_IS_EMPTY(&ifp->if_snd)) { 949 ifp->if_flags &= ~IFF_OACTIVE; 950 if (sc->sc_flags & TAP_NBIO) 951 error = EWOULDBLOCK; 952 else 953 error = cv_wait_sig(&sc->sc_cv, &sc->sc_lock); 954 955 if (error != 0) { 956 mutex_exit(&sc->sc_lock); 957 return error; 958 } 959 /* The device might have been downed */ 960 if ((ifp->if_flags & IFF_UP) == 0) { 961 mutex_exit(&sc->sc_lock); 962 return EHOSTDOWN; 963 } 964 } 965 966 IFQ_DEQUEUE(&ifp->if_snd, m); 967 mutex_exit(&sc->sc_lock); 968 969 ifp->if_flags &= ~IFF_OACTIVE; 970 if (m == NULL) { 971 error = 0; 972 goto out; 973 } 974 975 ifp->if_opackets++; 976 bpf_mtap(ifp, m, BPF_D_OUT); 977 978 /* 979 * One read is one packet. 980 */ 981 do { 982 error = uiomove(mtod(m, void *), 983 min(m->m_len, uio->uio_resid), uio); 984 m = n = m_free(m); 985 } while (m != NULL && uio->uio_resid > 0 && error == 0); 986 987 if (m != NULL) 988 m_freem(m); 989 990 out: 991 return error; 992 } 993 994 static int 995 tap_fops_stat(file_t *fp, struct stat *st) 996 { 997 int error = 0; 998 struct tap_softc *sc; 999 int unit = fp->f_devunit; 1000 1001 (void)memset(st, 0, sizeof(*st)); 1002 1003 KERNEL_LOCK(1, NULL); 1004 sc = device_lookup_private(&tap_cd, unit); 1005 if (sc == NULL) { 1006 error = ENXIO; 1007 goto out; 1008 } 1009 1010 st->st_dev = makedev(cdevsw_lookup_major(&tap_cdevsw), unit); 1011 st->st_atimespec = sc->sc_atime; 1012 st->st_mtimespec = sc->sc_mtime; 1013 st->st_ctimespec = st->st_birthtimespec = sc->sc_btime; 1014 st->st_uid = kauth_cred_geteuid(fp->f_cred); 1015 st->st_gid = kauth_cred_getegid(fp->f_cred); 1016 out: 1017 KERNEL_UNLOCK_ONE(NULL); 1018 return error; 1019 } 1020 1021 static int 1022 tap_cdev_write(dev_t dev, struct uio *uio, int flags) 1023 { 1024 return tap_dev_write(minor(dev), uio, flags); 1025 } 1026 1027 static int 1028 tap_fops_write(file_t *fp, off_t *offp, struct uio *uio, 1029 kauth_cred_t cred, int flags) 1030 { 1031 int error; 1032 1033 KERNEL_LOCK(1, NULL); 1034 error = tap_dev_write(fp->f_devunit, uio, flags); 1035 KERNEL_UNLOCK_ONE(NULL); 1036 return error; 1037 } 1038 1039 static int 1040 tap_dev_write(int unit, struct uio *uio, int flags) 1041 { 1042 struct tap_softc *sc = 1043 device_lookup_private(&tap_cd, unit); 1044 struct ifnet *ifp; 1045 struct mbuf *m, **mp; 1046 int error = 0; 1047 1048 if (sc == NULL) 1049 return ENXIO; 1050 1051 getnanotime(&sc->sc_mtime); 1052 ifp = &sc->sc_ec.ec_if; 1053 1054 /* One write, one packet, that's the rule */ 1055 MGETHDR(m, M_DONTWAIT, MT_DATA); 1056 if (m == NULL) { 1057 ifp->if_ierrors++; 1058 return ENOBUFS; 1059 } 1060 m->m_pkthdr.len = uio->uio_resid; 1061 1062 mp = &m; 1063 while (error == 0 && uio->uio_resid > 0) { 1064 if (*mp != m) { 1065 MGET(*mp, M_DONTWAIT, MT_DATA); 1066 if (*mp == NULL) { 1067 error = ENOBUFS; 1068 break; 1069 } 1070 } 1071 (*mp)->m_len = min(MHLEN, uio->uio_resid); 1072 error = uiomove(mtod(*mp, void *), (*mp)->m_len, uio); 1073 mp = &(*mp)->m_next; 1074 } 1075 if (error) { 1076 ifp->if_ierrors++; 1077 m_freem(m); 1078 return error; 1079 } 1080 1081 m_set_rcvif(m, ifp); 1082 1083 if_percpuq_enqueue(ifp->if_percpuq, m); 1084 1085 return 0; 1086 } 1087 1088 static int 1089 tap_cdev_ioctl(dev_t dev, u_long cmd, void *data, int flags, 1090 struct lwp *l) 1091 { 1092 return tap_dev_ioctl(minor(dev), cmd, data, l); 1093 } 1094 1095 static int 1096 tap_fops_ioctl(file_t *fp, u_long cmd, void *data) 1097 { 1098 return tap_dev_ioctl(fp->f_devunit, cmd, data, curlwp); 1099 } 1100 1101 static int 1102 tap_dev_ioctl(int unit, u_long cmd, void *data, struct lwp *l) 1103 { 1104 struct tap_softc *sc = device_lookup_private(&tap_cd, unit); 1105 1106 if (sc == NULL) 1107 return ENXIO; 1108 1109 switch (cmd) { 1110 case FIONREAD: 1111 { 1112 struct ifnet *ifp = &sc->sc_ec.ec_if; 1113 struct mbuf *m; 1114 int s; 1115 1116 s = splnet(); 1117 IFQ_POLL(&ifp->if_snd, m); 1118 1119 if (m == NULL) 1120 *(int *)data = 0; 1121 else 1122 *(int *)data = m->m_pkthdr.len; 1123 splx(s); 1124 return 0; 1125 } 1126 case TIOCSPGRP: 1127 case FIOSETOWN: 1128 return fsetown(&sc->sc_pgid, cmd, data); 1129 case TIOCGPGRP: 1130 case FIOGETOWN: 1131 return fgetown(sc->sc_pgid, cmd, data); 1132 case FIOASYNC: 1133 if (*(int *)data) { 1134 if (sc->sc_sih == NULL) { 1135 sc->sc_sih = softint_establish(SOFTINT_CLOCK, 1136 tap_softintr, sc); 1137 if (sc->sc_sih == NULL) 1138 return EBUSY; /* XXX */ 1139 } 1140 sc->sc_flags |= TAP_ASYNCIO; 1141 } else { 1142 sc->sc_flags &= ~TAP_ASYNCIO; 1143 if (sc->sc_sih != NULL) { 1144 softint_disestablish(sc->sc_sih); 1145 sc->sc_sih = NULL; 1146 } 1147 } 1148 return 0; 1149 case FIONBIO: 1150 if (*(int *)data) 1151 sc->sc_flags |= TAP_NBIO; 1152 else 1153 sc->sc_flags &= ~TAP_NBIO; 1154 return 0; 1155 #ifdef OTAPGIFNAME 1156 case OTAPGIFNAME: 1157 #endif 1158 case TAPGIFNAME: 1159 { 1160 struct ifreq *ifr = (struct ifreq *)data; 1161 struct ifnet *ifp = &sc->sc_ec.ec_if; 1162 1163 strlcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1164 return 0; 1165 } 1166 default: 1167 return ENOTTY; 1168 } 1169 } 1170 1171 static int 1172 tap_cdev_poll(dev_t dev, int events, struct lwp *l) 1173 { 1174 return tap_dev_poll(minor(dev), events, l); 1175 } 1176 1177 static int 1178 tap_fops_poll(file_t *fp, int events) 1179 { 1180 return tap_dev_poll(fp->f_devunit, events, curlwp); 1181 } 1182 1183 static int 1184 tap_dev_poll(int unit, int events, struct lwp *l) 1185 { 1186 struct tap_softc *sc = 1187 device_lookup_private(&tap_cd, unit); 1188 int revents = 0; 1189 1190 if (sc == NULL) 1191 return POLLERR; 1192 1193 if (events & (POLLIN|POLLRDNORM)) { 1194 struct ifnet *ifp = &sc->sc_ec.ec_if; 1195 struct mbuf *m; 1196 int s; 1197 1198 s = splnet(); 1199 IFQ_POLL(&ifp->if_snd, m); 1200 1201 if (m != NULL) 1202 revents |= events & (POLLIN|POLLRDNORM); 1203 else { 1204 mutex_spin_enter(&sc->sc_lock); 1205 selrecord(l, &sc->sc_rsel); 1206 mutex_spin_exit(&sc->sc_lock); 1207 } 1208 splx(s); 1209 } 1210 revents |= events & (POLLOUT|POLLWRNORM); 1211 1212 return revents; 1213 } 1214 1215 static struct filterops tap_read_filterops = { 1, NULL, tap_kqdetach, 1216 tap_kqread }; 1217 static struct filterops tap_seltrue_filterops = { 1, NULL, tap_kqdetach, 1218 filt_seltrue }; 1219 1220 static int 1221 tap_cdev_kqfilter(dev_t dev, struct knote *kn) 1222 { 1223 return tap_dev_kqfilter(minor(dev), kn); 1224 } 1225 1226 static int 1227 tap_fops_kqfilter(file_t *fp, struct knote *kn) 1228 { 1229 return tap_dev_kqfilter(fp->f_devunit, kn); 1230 } 1231 1232 static int 1233 tap_dev_kqfilter(int unit, struct knote *kn) 1234 { 1235 struct tap_softc *sc = 1236 device_lookup_private(&tap_cd, unit); 1237 1238 if (sc == NULL) 1239 return ENXIO; 1240 1241 KERNEL_LOCK(1, NULL); 1242 switch(kn->kn_filter) { 1243 case EVFILT_READ: 1244 kn->kn_fop = &tap_read_filterops; 1245 break; 1246 case EVFILT_WRITE: 1247 kn->kn_fop = &tap_seltrue_filterops; 1248 break; 1249 default: 1250 KERNEL_UNLOCK_ONE(NULL); 1251 return EINVAL; 1252 } 1253 1254 kn->kn_hook = sc; 1255 mutex_spin_enter(&sc->sc_lock); 1256 SLIST_INSERT_HEAD(&sc->sc_rsel.sel_klist, kn, kn_selnext); 1257 mutex_spin_exit(&sc->sc_lock); 1258 KERNEL_UNLOCK_ONE(NULL); 1259 return 0; 1260 } 1261 1262 static void 1263 tap_kqdetach(struct knote *kn) 1264 { 1265 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1266 1267 KERNEL_LOCK(1, NULL); 1268 mutex_spin_enter(&sc->sc_lock); 1269 SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext); 1270 mutex_spin_exit(&sc->sc_lock); 1271 KERNEL_UNLOCK_ONE(NULL); 1272 } 1273 1274 static int 1275 tap_kqread(struct knote *kn, long hint) 1276 { 1277 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1278 struct ifnet *ifp = &sc->sc_ec.ec_if; 1279 struct mbuf *m; 1280 int s, rv; 1281 1282 KERNEL_LOCK(1, NULL); 1283 s = splnet(); 1284 IFQ_POLL(&ifp->if_snd, m); 1285 1286 if (m == NULL) 1287 kn->kn_data = 0; 1288 else 1289 kn->kn_data = m->m_pkthdr.len; 1290 splx(s); 1291 rv = (kn->kn_data != 0 ? 1 : 0); 1292 KERNEL_UNLOCK_ONE(NULL); 1293 return rv; 1294 } 1295 1296 /* 1297 * sysctl management routines 1298 * You can set the address of an interface through: 1299 * net.link.tap.tap<number> 1300 * 1301 * Note the consistent use of tap_log in order to use 1302 * sysctl_teardown at unload time. 1303 * 1304 * In the kernel you will find a lot of SYSCTL_SETUP blocks. Those 1305 * blocks register a function in a special section of the kernel 1306 * (called a link set) which is used at init_sysctl() time to cycle 1307 * through all those functions to create the kernel's sysctl tree. 1308 * 1309 * It is not possible to use link sets in a module, so the 1310 * easiest is to simply call our own setup routine at load time. 1311 * 1312 * In the SYSCTL_SETUP blocks you find in the kernel, nodes have the 1313 * CTLFLAG_PERMANENT flag, meaning they cannot be removed. Once the 1314 * whole kernel sysctl tree is built, it is not possible to add any 1315 * permanent node. 1316 * 1317 * It should be noted that we're not saving the sysctlnode pointer 1318 * we are returned when creating the "tap" node. That structure 1319 * cannot be trusted once out of the calling function, as it might 1320 * get reused. So we just save the MIB number, and always give the 1321 * full path starting from the root for later calls to sysctl_createv 1322 * and sysctl_destroyv. 1323 */ 1324 static void 1325 sysctl_tap_setup(struct sysctllog **clog) 1326 { 1327 const struct sysctlnode *node; 1328 int error = 0; 1329 1330 if ((error = sysctl_createv(clog, 0, NULL, NULL, 1331 CTLFLAG_PERMANENT, 1332 CTLTYPE_NODE, "link", NULL, 1333 NULL, 0, NULL, 0, 1334 CTL_NET, AF_LINK, CTL_EOL)) != 0) 1335 return; 1336 1337 /* 1338 * The first four parameters of sysctl_createv are for management. 1339 * 1340 * The four that follows, here starting with a '0' for the flags, 1341 * describe the node. 1342 * 1343 * The next series of four set its value, through various possible 1344 * means. 1345 * 1346 * Last but not least, the path to the node is described. That path 1347 * is relative to the given root (third argument). Here we're 1348 * starting from the root. 1349 */ 1350 if ((error = sysctl_createv(clog, 0, NULL, &node, 1351 CTLFLAG_PERMANENT, 1352 CTLTYPE_NODE, "tap", NULL, 1353 NULL, 0, NULL, 0, 1354 CTL_NET, AF_LINK, CTL_CREATE, CTL_EOL)) != 0) 1355 return; 1356 tap_node = node->sysctl_num; 1357 } 1358 1359 /* 1360 * The helper functions make Andrew Brown's interface really 1361 * shine. It makes possible to create value on the fly whether 1362 * the sysctl value is read or written. 1363 * 1364 * As shown as an example in the man page, the first step is to 1365 * create a copy of the node to have sysctl_lookup work on it. 1366 * 1367 * Here, we have more work to do than just a copy, since we have 1368 * to create the string. The first step is to collect the actual 1369 * value of the node, which is a convenient pointer to the softc 1370 * of the interface. From there we create the string and use it 1371 * as the value, but only for the *copy* of the node. 1372 * 1373 * Then we let sysctl_lookup do the magic, which consists in 1374 * setting oldp and newp as required by the operation. When the 1375 * value is read, that means that the string will be copied to 1376 * the user, and when it is written, the new value will be copied 1377 * over in the addr array. 1378 * 1379 * If newp is NULL, the user was reading the value, so we don't 1380 * have anything else to do. If a new value was written, we 1381 * have to check it. 1382 * 1383 * If it is incorrect, we can return an error and leave 'node' as 1384 * it is: since it is a copy of the actual node, the change will 1385 * be forgotten. 1386 * 1387 * Upon a correct input, we commit the change to the ifnet 1388 * structure of our interface. 1389 */ 1390 static int 1391 tap_sysctl_handler(SYSCTLFN_ARGS) 1392 { 1393 struct sysctlnode node; 1394 struct tap_softc *sc; 1395 struct ifnet *ifp; 1396 int error; 1397 size_t len; 1398 char addr[3 * ETHER_ADDR_LEN]; 1399 uint8_t enaddr[ETHER_ADDR_LEN]; 1400 1401 node = *rnode; 1402 sc = node.sysctl_data; 1403 ifp = &sc->sc_ec.ec_if; 1404 (void)ether_snprintf(addr, sizeof(addr), CLLADDR(ifp->if_sadl)); 1405 node.sysctl_data = addr; 1406 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1407 if (error || newp == NULL) 1408 return error; 1409 1410 len = strlen(addr); 1411 if (len < 11 || len > 17) 1412 return EINVAL; 1413 1414 /* Commit change */ 1415 if (ether_aton_r(enaddr, sizeof(enaddr), addr) != 0) 1416 return EINVAL; 1417 if_set_sadl(ifp, enaddr, ETHER_ADDR_LEN, false); 1418 return error; 1419 } 1420 1421 /* 1422 * Module infrastructure 1423 */ 1424 #include "if_module.h" 1425 1426 IF_MODULE(MODULE_CLASS_DRIVER, tap, "") 1427