1 /* $NetBSD: if_tap.c,v 1.77 2014/07/25 08:10:40 dholland 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 1.77 2014/07/25 08:10:40 dholland 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/systm.h> 46 #include <sys/kernel.h> 47 #include <sys/malloc.h> 48 #include <sys/conf.h> 49 #include <sys/cprng.h> 50 #include <sys/device.h> 51 #include <sys/file.h> 52 #include <sys/filedesc.h> 53 #include <sys/ksyms.h> 54 #include <sys/poll.h> 55 #include <sys/proc.h> 56 #include <sys/select.h> 57 #include <sys/sockio.h> 58 #if defined(COMPAT_40) || defined(MODULAR) 59 #include <sys/sysctl.h> 60 #endif 61 #include <sys/kauth.h> 62 #include <sys/mutex.h> 63 #include <sys/intr.h> 64 #include <sys/stat.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 #if defined(COMPAT_40) || defined(MODULAR) 76 /* 77 * sysctl node management 78 * 79 * It's not really possible to use a SYSCTL_SETUP block with 80 * current module implementation, so it is easier to just define 81 * our own function. 82 * 83 * The handler function is a "helper" in Andrew Brown's sysctl 84 * framework terminology. It is used as a gateway for sysctl 85 * requests over the nodes. 86 * 87 * tap_log allows the module to log creations of nodes and 88 * destroy them all at once using sysctl_teardown. 89 */ 90 static int tap_node; 91 static int tap_sysctl_handler(SYSCTLFN_PROTO); 92 SYSCTL_SETUP_PROTO(sysctl_tap_setup); 93 #endif 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_rdlock; 114 kmutex_t sc_kqlock; 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 void tapattach(int); 124 125 static int tap_match(device_t, cfdata_t, void *); 126 static void tap_attach(device_t, device_t, void *); 127 static int tap_detach(device_t, int); 128 129 CFATTACH_DECL_NEW(tap, sizeof(struct tap_softc), 130 tap_match, tap_attach, tap_detach, NULL); 131 extern struct cfdriver tap_cd; 132 133 /* Real device access routines */ 134 static int tap_dev_close(struct tap_softc *); 135 static int tap_dev_read(int, struct uio *, int); 136 static int tap_dev_write(int, struct uio *, int); 137 static int tap_dev_ioctl(int, u_long, void *, struct lwp *); 138 static int tap_dev_poll(int, int, struct lwp *); 139 static int tap_dev_kqfilter(int, struct knote *); 140 141 /* Fileops access routines */ 142 static int tap_fops_close(file_t *); 143 static int tap_fops_read(file_t *, off_t *, struct uio *, 144 kauth_cred_t, int); 145 static int tap_fops_write(file_t *, off_t *, struct uio *, 146 kauth_cred_t, int); 147 static int tap_fops_ioctl(file_t *, u_long, void *); 148 static int tap_fops_poll(file_t *, int); 149 static int tap_fops_stat(file_t *, struct stat *); 150 static int tap_fops_kqfilter(file_t *, struct knote *); 151 152 static const struct fileops tap_fileops = { 153 .fo_read = tap_fops_read, 154 .fo_write = tap_fops_write, 155 .fo_ioctl = tap_fops_ioctl, 156 .fo_fcntl = fnullop_fcntl, 157 .fo_poll = tap_fops_poll, 158 .fo_stat = tap_fops_stat, 159 .fo_close = tap_fops_close, 160 .fo_kqfilter = tap_fops_kqfilter, 161 .fo_restart = fnullop_restart, 162 }; 163 164 /* Helper for cloning open() */ 165 static int tap_dev_cloner(struct lwp *); 166 167 /* Character device routines */ 168 static int tap_cdev_open(dev_t, int, int, struct lwp *); 169 static int tap_cdev_close(dev_t, int, int, struct lwp *); 170 static int tap_cdev_read(dev_t, struct uio *, int); 171 static int tap_cdev_write(dev_t, struct uio *, int); 172 static int tap_cdev_ioctl(dev_t, u_long, void *, int, struct lwp *); 173 static int tap_cdev_poll(dev_t, int, struct lwp *); 174 static int tap_cdev_kqfilter(dev_t, struct knote *); 175 176 const struct cdevsw tap_cdevsw = { 177 .d_open = tap_cdev_open, 178 .d_close = tap_cdev_close, 179 .d_read = tap_cdev_read, 180 .d_write = tap_cdev_write, 181 .d_ioctl = tap_cdev_ioctl, 182 .d_stop = nostop, 183 .d_tty = notty, 184 .d_poll = tap_cdev_poll, 185 .d_mmap = nommap, 186 .d_kqfilter = tap_cdev_kqfilter, 187 .d_discard = nodiscard, 188 .d_flag = D_OTHER 189 }; 190 191 #define TAP_CLONER 0xfffff /* Maximal minor value */ 192 193 /* kqueue-related routines */ 194 static void tap_kqdetach(struct knote *); 195 static int tap_kqread(struct knote *, long); 196 197 /* 198 * Those are needed by the if_media interface. 199 */ 200 201 static int tap_mediachange(struct ifnet *); 202 static void tap_mediastatus(struct ifnet *, struct ifmediareq *); 203 204 /* 205 * Those are needed by the ifnet interface, and would typically be 206 * there for any network interface driver. 207 * Some other routines are optional: watchdog and drain. 208 */ 209 210 static void tap_start(struct ifnet *); 211 static void tap_stop(struct ifnet *, int); 212 static int tap_init(struct ifnet *); 213 static int tap_ioctl(struct ifnet *, u_long, void *); 214 215 /* Internal functions */ 216 #if defined(COMPAT_40) || defined(MODULAR) 217 static int tap_lifaddr(struct ifnet *, u_long, struct ifaliasreq *); 218 #endif 219 static void tap_softintr(void *); 220 221 /* 222 * tap is a clonable interface, although it is highly unrealistic for 223 * an Ethernet device. 224 * 225 * Here are the bits needed for a clonable interface. 226 */ 227 static int tap_clone_create(struct if_clone *, int); 228 static int tap_clone_destroy(struct ifnet *); 229 230 struct if_clone tap_cloners = IF_CLONE_INITIALIZER("tap", 231 tap_clone_create, 232 tap_clone_destroy); 233 234 /* Helper functionis shared by the two cloning code paths */ 235 static struct tap_softc * tap_clone_creator(int); 236 int tap_clone_destroyer(device_t); 237 238 void 239 tapattach(int n) 240 { 241 int error; 242 243 error = config_cfattach_attach(tap_cd.cd_name, &tap_ca); 244 if (error) { 245 aprint_error("%s: unable to register cfattach\n", 246 tap_cd.cd_name); 247 (void)config_cfdriver_detach(&tap_cd); 248 return; 249 } 250 251 if_clone_attach(&tap_cloners); 252 } 253 254 /* Pretty much useless for a pseudo-device */ 255 static int 256 tap_match(device_t parent, cfdata_t cfdata, void *arg) 257 { 258 259 return (1); 260 } 261 262 void 263 tap_attach(device_t parent, device_t self, void *aux) 264 { 265 struct tap_softc *sc = device_private(self); 266 struct ifnet *ifp; 267 #if defined(COMPAT_40) || defined(MODULAR) 268 const struct sysctlnode *node; 269 int error; 270 #endif 271 uint8_t enaddr[ETHER_ADDR_LEN] = 272 { 0xf2, 0x0b, 0xa4, 0xff, 0xff, 0xff }; 273 char enaddrstr[3 * ETHER_ADDR_LEN]; 274 275 sc->sc_dev = self; 276 sc->sc_sih = NULL; 277 getnanotime(&sc->sc_btime); 278 sc->sc_atime = sc->sc_mtime = sc->sc_btime; 279 280 if (!pmf_device_register(self, NULL, NULL)) 281 aprint_error_dev(self, "couldn't establish power handler\n"); 282 283 /* 284 * In order to obtain unique initial Ethernet address on a host, 285 * do some randomisation. It's not meant for anything but avoiding 286 * hard-coding an address. 287 */ 288 cprng_fast(&enaddr[3], 3); 289 290 aprint_verbose_dev(self, "Ethernet address %s\n", 291 ether_snprintf(enaddrstr, sizeof(enaddrstr), enaddr)); 292 293 /* 294 * Why 1000baseT? Why not? You can add more. 295 * 296 * Note that there are 3 steps: init, one or several additions to 297 * list of supported media, and in the end, the selection of one 298 * of them. 299 */ 300 ifmedia_init(&sc->sc_im, 0, tap_mediachange, tap_mediastatus); 301 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T, 0, NULL); 302 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T|IFM_FDX, 0, NULL); 303 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX, 0, NULL); 304 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX|IFM_FDX, 0, NULL); 305 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T, 0, NULL); 306 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T|IFM_FDX, 0, NULL); 307 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_AUTO, 0, NULL); 308 ifmedia_set(&sc->sc_im, IFM_ETHER|IFM_AUTO); 309 310 /* 311 * One should note that an interface must do multicast in order 312 * to support IPv6. 313 */ 314 ifp = &sc->sc_ec.ec_if; 315 strcpy(ifp->if_xname, device_xname(self)); 316 ifp->if_softc = sc; 317 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 318 ifp->if_ioctl = tap_ioctl; 319 ifp->if_start = tap_start; 320 ifp->if_stop = tap_stop; 321 ifp->if_init = tap_init; 322 IFQ_SET_READY(&ifp->if_snd); 323 324 sc->sc_ec.ec_capabilities = ETHERCAP_VLAN_MTU | ETHERCAP_JUMBO_MTU; 325 326 /* Those steps are mandatory for an Ethernet driver, the fisrt call 327 * being common to all network interface drivers. */ 328 if_attach(ifp); 329 ether_ifattach(ifp, enaddr); 330 331 sc->sc_flags = 0; 332 333 #if defined(COMPAT_40) || defined(MODULAR) 334 /* 335 * Add a sysctl node for that interface. 336 * 337 * The pointer transmitted is not a string, but instead a pointer to 338 * the softc structure, which we can use to build the string value on 339 * the fly in the helper function of the node. See the comments for 340 * tap_sysctl_handler for details. 341 * 342 * Usually sysctl_createv is called with CTL_CREATE as the before-last 343 * component. However, we can allocate a number ourselves, as we are 344 * the only consumer of the net.link.<iface> node. In this case, the 345 * unit number is conveniently used to number the node. CTL_CREATE 346 * would just work, too. 347 */ 348 if ((error = sysctl_createv(NULL, 0, NULL, 349 &node, CTLFLAG_READWRITE, 350 CTLTYPE_STRING, device_xname(self), NULL, 351 tap_sysctl_handler, 0, (void *)sc, 18, 352 CTL_NET, AF_LINK, tap_node, device_unit(sc->sc_dev), 353 CTL_EOL)) != 0) 354 aprint_error_dev(self, "sysctl_createv returned %d, ignoring\n", 355 error); 356 #endif 357 358 /* 359 * Initialize the two locks for the device. 360 * 361 * We need a lock here because even though the tap device can be 362 * opened only once, the file descriptor might be passed to another 363 * process, say a fork(2)ed child. 364 * 365 * The Giant saves us from most of the hassle, but since the read 366 * operation can sleep, we don't want two processes to wake up at 367 * the same moment and both try and dequeue a single packet. 368 * 369 * The queue for event listeners (used by kqueue(9), see below) has 370 * to be protected too, so use a spin lock. 371 */ 372 mutex_init(&sc->sc_rdlock, MUTEX_DEFAULT, IPL_NONE); 373 mutex_init(&sc->sc_kqlock, MUTEX_DEFAULT, IPL_VM); 374 375 selinit(&sc->sc_rsel); 376 } 377 378 /* 379 * When detaching, we do the inverse of what is done in the attach 380 * routine, in reversed order. 381 */ 382 static int 383 tap_detach(device_t self, int flags) 384 { 385 struct tap_softc *sc = device_private(self); 386 struct ifnet *ifp = &sc->sc_ec.ec_if; 387 #if defined(COMPAT_40) || defined(MODULAR) 388 int error; 389 #endif 390 int s; 391 392 sc->sc_flags |= TAP_GOING; 393 s = splnet(); 394 tap_stop(ifp, 1); 395 if_down(ifp); 396 splx(s); 397 398 if (sc->sc_sih != NULL) { 399 softint_disestablish(sc->sc_sih); 400 sc->sc_sih = NULL; 401 } 402 403 #if defined(COMPAT_40) || defined(MODULAR) 404 /* 405 * Destroying a single leaf is a very straightforward operation using 406 * sysctl_destroyv. One should be sure to always end the path with 407 * CTL_EOL. 408 */ 409 if ((error = sysctl_destroyv(NULL, CTL_NET, AF_LINK, tap_node, 410 device_unit(sc->sc_dev), CTL_EOL)) != 0) 411 aprint_error_dev(self, 412 "sysctl_destroyv returned %d, ignoring\n", error); 413 #endif 414 ether_ifdetach(ifp); 415 if_detach(ifp); 416 ifmedia_delete_instance(&sc->sc_im, IFM_INST_ANY); 417 seldestroy(&sc->sc_rsel); 418 mutex_destroy(&sc->sc_rdlock); 419 mutex_destroy(&sc->sc_kqlock); 420 421 pmf_device_deregister(self); 422 423 return (0); 424 } 425 426 /* 427 * This function is called by the ifmedia layer to notify the driver 428 * that the user requested a media change. A real driver would 429 * reconfigure the hardware. 430 */ 431 static int 432 tap_mediachange(struct ifnet *ifp) 433 { 434 return (0); 435 } 436 437 /* 438 * Here the user asks for the currently used media. 439 */ 440 static void 441 tap_mediastatus(struct ifnet *ifp, struct ifmediareq *imr) 442 { 443 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 444 imr->ifm_active = sc->sc_im.ifm_cur->ifm_media; 445 } 446 447 /* 448 * This is the function where we SEND packets. 449 * 450 * There is no 'receive' equivalent. A typical driver will get 451 * interrupts from the hardware, and from there will inject new packets 452 * into the network stack. 453 * 454 * Once handled, a packet must be freed. A real driver might not be able 455 * to fit all the pending packets into the hardware, and is allowed to 456 * return before having sent all the packets. It should then use the 457 * if_flags flag IFF_OACTIVE to notify the upper layer. 458 * 459 * There are also other flags one should check, such as IFF_PAUSE. 460 * 461 * It is our duty to make packets available to BPF listeners. 462 * 463 * You should be aware that this function is called by the Ethernet layer 464 * at splnet(). 465 * 466 * When the device is opened, we have to pass the packet(s) to the 467 * userland. For that we stay in OACTIVE mode while the userland gets 468 * the packets, and we send a signal to the processes waiting to read. 469 * 470 * wakeup(sc) is the counterpart to the tsleep call in 471 * tap_dev_read, while selnotify() is used for kevent(2) and 472 * poll(2) (which includes select(2)) listeners. 473 */ 474 static void 475 tap_start(struct ifnet *ifp) 476 { 477 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 478 struct mbuf *m0; 479 480 if ((sc->sc_flags & TAP_INUSE) == 0) { 481 /* Simply drop packets */ 482 for(;;) { 483 IFQ_DEQUEUE(&ifp->if_snd, m0); 484 if (m0 == NULL) 485 return; 486 487 ifp->if_opackets++; 488 bpf_mtap(ifp, m0); 489 490 m_freem(m0); 491 } 492 } else if (!IFQ_IS_EMPTY(&ifp->if_snd)) { 493 ifp->if_flags |= IFF_OACTIVE; 494 wakeup(sc); 495 selnotify(&sc->sc_rsel, 0, 1); 496 if (sc->sc_flags & TAP_ASYNCIO) 497 softint_schedule(sc->sc_sih); 498 } 499 } 500 501 static void 502 tap_softintr(void *cookie) 503 { 504 struct tap_softc *sc; 505 struct ifnet *ifp; 506 int a, b; 507 508 sc = cookie; 509 510 if (sc->sc_flags & TAP_ASYNCIO) { 511 ifp = &sc->sc_ec.ec_if; 512 if (ifp->if_flags & IFF_RUNNING) { 513 a = POLL_IN; 514 b = POLLIN|POLLRDNORM; 515 } else { 516 a = POLL_HUP; 517 b = 0; 518 } 519 fownsignal(sc->sc_pgid, SIGIO, a, b, NULL); 520 } 521 } 522 523 /* 524 * A typical driver will only contain the following handlers for 525 * ioctl calls, except SIOCSIFPHYADDR. 526 * The latter is a hack I used to set the Ethernet address of the 527 * faked device. 528 * 529 * Note that both ifmedia_ioctl() and ether_ioctl() have to be 530 * called under splnet(). 531 */ 532 static int 533 tap_ioctl(struct ifnet *ifp, u_long cmd, void *data) 534 { 535 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 536 struct ifreq *ifr = (struct ifreq *)data; 537 int s, error; 538 539 s = splnet(); 540 541 switch (cmd) { 542 #ifdef OSIOCSIFMEDIA 543 case OSIOCSIFMEDIA: 544 #endif 545 case SIOCSIFMEDIA: 546 case SIOCGIFMEDIA: 547 error = ifmedia_ioctl(ifp, ifr, &sc->sc_im, cmd); 548 break; 549 #if defined(COMPAT_40) || defined(MODULAR) 550 case SIOCSIFPHYADDR: 551 error = tap_lifaddr(ifp, cmd, (struct ifaliasreq *)data); 552 break; 553 #endif 554 default: 555 error = ether_ioctl(ifp, cmd, data); 556 if (error == ENETRESET) 557 error = 0; 558 break; 559 } 560 561 splx(s); 562 563 return (error); 564 } 565 566 #if defined(COMPAT_40) || defined(MODULAR) 567 /* 568 * Helper function to set Ethernet address. This has been replaced by 569 * the generic SIOCALIFADDR ioctl on a PF_LINK socket. 570 */ 571 static int 572 tap_lifaddr(struct ifnet *ifp, u_long cmd, struct ifaliasreq *ifra) 573 { 574 const struct sockaddr *sa = &ifra->ifra_addr; 575 576 if (sa->sa_family != AF_LINK) 577 return (EINVAL); 578 579 if_set_sadl(ifp, sa->sa_data, ETHER_ADDR_LEN, false); 580 581 return (0); 582 } 583 #endif 584 585 /* 586 * _init() would typically be called when an interface goes up, 587 * meaning it should configure itself into the state in which it 588 * can send packets. 589 */ 590 static int 591 tap_init(struct ifnet *ifp) 592 { 593 ifp->if_flags |= IFF_RUNNING; 594 595 tap_start(ifp); 596 597 return (0); 598 } 599 600 /* 601 * _stop() is called when an interface goes down. It is our 602 * responsability to validate that state by clearing the 603 * IFF_RUNNING flag. 604 * 605 * We have to wake up all the sleeping processes to have the pending 606 * read requests cancelled. 607 */ 608 static void 609 tap_stop(struct ifnet *ifp, int disable) 610 { 611 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 612 613 ifp->if_flags &= ~IFF_RUNNING; 614 wakeup(sc); 615 selnotify(&sc->sc_rsel, 0, 1); 616 if (sc->sc_flags & TAP_ASYNCIO) 617 softint_schedule(sc->sc_sih); 618 } 619 620 /* 621 * The 'create' command of ifconfig can be used to create 622 * any numbered instance of a given device. Thus we have to 623 * make sure we have enough room in cd_devs to create the 624 * user-specified instance. config_attach_pseudo will do this 625 * for us. 626 */ 627 static int 628 tap_clone_create(struct if_clone *ifc, int unit) 629 { 630 if (tap_clone_creator(unit) == NULL) { 631 aprint_error("%s%d: unable to attach an instance\n", 632 tap_cd.cd_name, unit); 633 return (ENXIO); 634 } 635 636 return (0); 637 } 638 639 /* 640 * tap(4) can be cloned by two ways: 641 * using 'ifconfig tap0 create', which will use the network 642 * interface cloning API, and call tap_clone_create above. 643 * opening the cloning device node, whose minor number is TAP_CLONER. 644 * See below for an explanation on how this part work. 645 */ 646 static struct tap_softc * 647 tap_clone_creator(int unit) 648 { 649 struct cfdata *cf; 650 651 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 652 cf->cf_name = tap_cd.cd_name; 653 cf->cf_atname = tap_ca.ca_name; 654 if (unit == -1) { 655 /* let autoconf find the first free one */ 656 cf->cf_unit = 0; 657 cf->cf_fstate = FSTATE_STAR; 658 } else { 659 cf->cf_unit = unit; 660 cf->cf_fstate = FSTATE_NOTFOUND; 661 } 662 663 return device_private(config_attach_pseudo(cf)); 664 } 665 666 /* 667 * The clean design of if_clone and autoconf(9) makes that part 668 * really straightforward. The second argument of config_detach 669 * means neither QUIET nor FORCED. 670 */ 671 static int 672 tap_clone_destroy(struct ifnet *ifp) 673 { 674 struct tap_softc *sc = ifp->if_softc; 675 676 return tap_clone_destroyer(sc->sc_dev); 677 } 678 679 int 680 tap_clone_destroyer(device_t dev) 681 { 682 cfdata_t cf = device_cfdata(dev); 683 int error; 684 685 if ((error = config_detach(dev, 0)) != 0) 686 aprint_error_dev(dev, "unable to detach instance\n"); 687 free(cf, M_DEVBUF); 688 689 return (error); 690 } 691 692 /* 693 * tap(4) is a bit of an hybrid device. It can be used in two different 694 * ways: 695 * 1. ifconfig tapN create, then use /dev/tapN to read/write off it. 696 * 2. open /dev/tap, get a new interface created and read/write off it. 697 * That interface is destroyed when the process that had it created exits. 698 * 699 * The first way is managed by the cdevsw structure, and you access interfaces 700 * through a (major, minor) mapping: tap4 is obtained by the minor number 701 * 4. The entry points for the cdevsw interface are prefixed by tap_cdev_. 702 * 703 * The second way is the so-called "cloning" device. It's a special minor 704 * number (chosen as the maximal number, to allow as much tap devices as 705 * possible). The user first opens the cloner (e.g., /dev/tap), and that 706 * call ends in tap_cdev_open. The actual place where it is handled is 707 * tap_dev_cloner. 708 * 709 * An tap device cannot be opened more than once at a time, so the cdevsw 710 * part of open() does nothing but noting that the interface is being used and 711 * hence ready to actually handle packets. 712 */ 713 714 static int 715 tap_cdev_open(dev_t dev, int flags, int fmt, struct lwp *l) 716 { 717 struct tap_softc *sc; 718 719 if (minor(dev) == TAP_CLONER) 720 return tap_dev_cloner(l); 721 722 sc = device_lookup_private(&tap_cd, minor(dev)); 723 if (sc == NULL) 724 return (ENXIO); 725 726 /* The device can only be opened once */ 727 if (sc->sc_flags & TAP_INUSE) 728 return (EBUSY); 729 sc->sc_flags |= TAP_INUSE; 730 return (0); 731 } 732 733 /* 734 * There are several kinds of cloning devices, and the most simple is the one 735 * tap(4) uses. What it does is change the file descriptor with a new one, 736 * with its own fileops structure (which maps to the various read, write, 737 * ioctl functions). It starts allocating a new file descriptor with falloc, 738 * then actually creates the new tap devices. 739 * 740 * Once those two steps are successful, we can re-wire the existing file 741 * descriptor to its new self. This is done with fdclone(): it fills the fp 742 * structure as needed (notably f_data gets filled with the fifth parameter 743 * passed, the unit of the tap device which will allows us identifying the 744 * device later), and returns EMOVEFD. 745 * 746 * That magic value is interpreted by sys_open() which then replaces the 747 * current file descriptor by the new one (through a magic member of struct 748 * lwp, l_dupfd). 749 * 750 * The tap device is flagged as being busy since it otherwise could be 751 * externally accessed through the corresponding device node with the cdevsw 752 * interface. 753 */ 754 755 static int 756 tap_dev_cloner(struct lwp *l) 757 { 758 struct tap_softc *sc; 759 file_t *fp; 760 int error, fd; 761 762 if ((error = fd_allocfile(&fp, &fd)) != 0) 763 return (error); 764 765 if ((sc = tap_clone_creator(-1)) == NULL) { 766 fd_abort(curproc, fp, fd); 767 return (ENXIO); 768 } 769 770 sc->sc_flags |= TAP_INUSE; 771 772 return fd_clone(fp, fd, FREAD|FWRITE, &tap_fileops, 773 (void *)(intptr_t)device_unit(sc->sc_dev)); 774 } 775 776 /* 777 * While all other operations (read, write, ioctl, poll and kqfilter) are 778 * really the same whether we are in cdevsw or fileops mode, the close() 779 * function is slightly different in the two cases. 780 * 781 * As for the other, the core of it is shared in tap_dev_close. What 782 * it does is sufficient for the cdevsw interface, but the cloning interface 783 * needs another thing: the interface is destroyed when the processes that 784 * created it closes it. 785 */ 786 static int 787 tap_cdev_close(dev_t dev, int flags, int fmt, 788 struct lwp *l) 789 { 790 struct tap_softc *sc = 791 device_lookup_private(&tap_cd, minor(dev)); 792 793 if (sc == NULL) 794 return (ENXIO); 795 796 return tap_dev_close(sc); 797 } 798 799 /* 800 * It might happen that the administrator used ifconfig to externally destroy 801 * the interface. In that case, tap_fops_close will be called while 802 * tap_detach is already happening. If we called it again from here, we 803 * would dead lock. TAP_GOING ensures that this situation doesn't happen. 804 */ 805 static int 806 tap_fops_close(file_t *fp) 807 { 808 int unit = (intptr_t)fp->f_data; 809 struct tap_softc *sc; 810 int error; 811 812 sc = device_lookup_private(&tap_cd, unit); 813 if (sc == NULL) 814 return (ENXIO); 815 816 /* tap_dev_close currently always succeeds, but it might not 817 * always be the case. */ 818 KERNEL_LOCK(1, NULL); 819 if ((error = tap_dev_close(sc)) != 0) { 820 KERNEL_UNLOCK_ONE(NULL); 821 return (error); 822 } 823 824 /* Destroy the device now that it is no longer useful, 825 * unless it's already being destroyed. */ 826 if ((sc->sc_flags & TAP_GOING) != 0) { 827 KERNEL_UNLOCK_ONE(NULL); 828 return (0); 829 } 830 831 error = tap_clone_destroyer(sc->sc_dev); 832 KERNEL_UNLOCK_ONE(NULL); 833 return error; 834 } 835 836 static int 837 tap_dev_close(struct tap_softc *sc) 838 { 839 struct ifnet *ifp; 840 int s; 841 842 s = splnet(); 843 /* Let tap_start handle packets again */ 844 ifp = &sc->sc_ec.ec_if; 845 ifp->if_flags &= ~IFF_OACTIVE; 846 847 /* Purge output queue */ 848 if (!(IFQ_IS_EMPTY(&ifp->if_snd))) { 849 struct mbuf *m; 850 851 for (;;) { 852 IFQ_DEQUEUE(&ifp->if_snd, m); 853 if (m == NULL) 854 break; 855 856 ifp->if_opackets++; 857 bpf_mtap(ifp, m); 858 m_freem(m); 859 } 860 } 861 splx(s); 862 863 if (sc->sc_sih != NULL) { 864 softint_disestablish(sc->sc_sih); 865 sc->sc_sih = NULL; 866 } 867 sc->sc_flags &= ~(TAP_INUSE | TAP_ASYNCIO); 868 869 return (0); 870 } 871 872 static int 873 tap_cdev_read(dev_t dev, struct uio *uio, int flags) 874 { 875 return tap_dev_read(minor(dev), uio, flags); 876 } 877 878 static int 879 tap_fops_read(file_t *fp, off_t *offp, struct uio *uio, 880 kauth_cred_t cred, int flags) 881 { 882 int error; 883 884 KERNEL_LOCK(1, NULL); 885 error = tap_dev_read((intptr_t)fp->f_data, uio, flags); 886 KERNEL_UNLOCK_ONE(NULL); 887 return error; 888 } 889 890 static int 891 tap_dev_read(int unit, struct uio *uio, int flags) 892 { 893 struct tap_softc *sc = 894 device_lookup_private(&tap_cd, unit); 895 struct ifnet *ifp; 896 struct mbuf *m, *n; 897 int error = 0, s; 898 899 if (sc == NULL) 900 return (ENXIO); 901 902 getnanotime(&sc->sc_atime); 903 904 ifp = &sc->sc_ec.ec_if; 905 if ((ifp->if_flags & IFF_UP) == 0) 906 return (EHOSTDOWN); 907 908 /* 909 * In the TAP_NBIO case, we have to make sure we won't be sleeping 910 */ 911 if ((sc->sc_flags & TAP_NBIO) != 0) { 912 if (!mutex_tryenter(&sc->sc_rdlock)) 913 return (EWOULDBLOCK); 914 } else { 915 mutex_enter(&sc->sc_rdlock); 916 } 917 918 s = splnet(); 919 if (IFQ_IS_EMPTY(&ifp->if_snd)) { 920 ifp->if_flags &= ~IFF_OACTIVE; 921 /* 922 * We must release the lock before sleeping, and re-acquire it 923 * after. 924 */ 925 mutex_exit(&sc->sc_rdlock); 926 if (sc->sc_flags & TAP_NBIO) 927 error = EWOULDBLOCK; 928 else 929 error = tsleep(sc, PSOCK|PCATCH, "tap", 0); 930 splx(s); 931 932 if (error != 0) 933 return (error); 934 /* The device might have been downed */ 935 if ((ifp->if_flags & IFF_UP) == 0) 936 return (EHOSTDOWN); 937 if ((sc->sc_flags & TAP_NBIO)) { 938 if (!mutex_tryenter(&sc->sc_rdlock)) 939 return (EWOULDBLOCK); 940 } else { 941 mutex_enter(&sc->sc_rdlock); 942 } 943 s = splnet(); 944 } 945 946 IFQ_DEQUEUE(&ifp->if_snd, m); 947 ifp->if_flags &= ~IFF_OACTIVE; 948 splx(s); 949 if (m == NULL) { 950 error = 0; 951 goto out; 952 } 953 954 ifp->if_opackets++; 955 bpf_mtap(ifp, m); 956 957 /* 958 * One read is one packet. 959 */ 960 do { 961 error = uiomove(mtod(m, void *), 962 min(m->m_len, uio->uio_resid), uio); 963 MFREE(m, n); 964 m = n; 965 } while (m != NULL && uio->uio_resid > 0 && error == 0); 966 967 if (m != NULL) 968 m_freem(m); 969 970 out: 971 mutex_exit(&sc->sc_rdlock); 972 return (error); 973 } 974 975 static int 976 tap_fops_stat(file_t *fp, struct stat *st) 977 { 978 int error = 0; 979 struct tap_softc *sc; 980 int unit = (uintptr_t)fp->f_data; 981 982 (void)memset(st, 0, sizeof(*st)); 983 984 KERNEL_LOCK(1, NULL); 985 sc = device_lookup_private(&tap_cd, unit); 986 if (sc == NULL) { 987 error = ENXIO; 988 goto out; 989 } 990 991 st->st_dev = makedev(cdevsw_lookup_major(&tap_cdevsw), unit); 992 st->st_atimespec = sc->sc_atime; 993 st->st_mtimespec = sc->sc_mtime; 994 st->st_ctimespec = st->st_birthtimespec = sc->sc_btime; 995 st->st_uid = kauth_cred_geteuid(fp->f_cred); 996 st->st_gid = kauth_cred_getegid(fp->f_cred); 997 out: 998 KERNEL_UNLOCK_ONE(NULL); 999 return error; 1000 } 1001 1002 static int 1003 tap_cdev_write(dev_t dev, struct uio *uio, int flags) 1004 { 1005 return tap_dev_write(minor(dev), uio, flags); 1006 } 1007 1008 static int 1009 tap_fops_write(file_t *fp, off_t *offp, struct uio *uio, 1010 kauth_cred_t cred, int flags) 1011 { 1012 int error; 1013 1014 KERNEL_LOCK(1, NULL); 1015 error = tap_dev_write((intptr_t)fp->f_data, uio, flags); 1016 KERNEL_UNLOCK_ONE(NULL); 1017 return error; 1018 } 1019 1020 static int 1021 tap_dev_write(int unit, struct uio *uio, int flags) 1022 { 1023 struct tap_softc *sc = 1024 device_lookup_private(&tap_cd, unit); 1025 struct ifnet *ifp; 1026 struct mbuf *m, **mp; 1027 int error = 0; 1028 int s; 1029 1030 if (sc == NULL) 1031 return (ENXIO); 1032 1033 getnanotime(&sc->sc_mtime); 1034 ifp = &sc->sc_ec.ec_if; 1035 1036 /* One write, one packet, that's the rule */ 1037 MGETHDR(m, M_DONTWAIT, MT_DATA); 1038 if (m == NULL) { 1039 ifp->if_ierrors++; 1040 return (ENOBUFS); 1041 } 1042 m->m_pkthdr.len = uio->uio_resid; 1043 1044 mp = &m; 1045 while (error == 0 && uio->uio_resid > 0) { 1046 if (*mp != m) { 1047 MGET(*mp, M_DONTWAIT, MT_DATA); 1048 if (*mp == NULL) { 1049 error = ENOBUFS; 1050 break; 1051 } 1052 } 1053 (*mp)->m_len = min(MHLEN, uio->uio_resid); 1054 error = uiomove(mtod(*mp, void *), (*mp)->m_len, uio); 1055 mp = &(*mp)->m_next; 1056 } 1057 if (error) { 1058 ifp->if_ierrors++; 1059 m_freem(m); 1060 return (error); 1061 } 1062 1063 ifp->if_ipackets++; 1064 m->m_pkthdr.rcvif = ifp; 1065 1066 bpf_mtap(ifp, m); 1067 s = splnet(); 1068 (*ifp->if_input)(ifp, m); 1069 splx(s); 1070 1071 return (0); 1072 } 1073 1074 static int 1075 tap_cdev_ioctl(dev_t dev, u_long cmd, void *data, int flags, 1076 struct lwp *l) 1077 { 1078 return tap_dev_ioctl(minor(dev), cmd, data, l); 1079 } 1080 1081 static int 1082 tap_fops_ioctl(file_t *fp, u_long cmd, void *data) 1083 { 1084 return tap_dev_ioctl((intptr_t)fp->f_data, cmd, data, curlwp); 1085 } 1086 1087 static int 1088 tap_dev_ioctl(int unit, u_long cmd, void *data, struct lwp *l) 1089 { 1090 struct tap_softc *sc = device_lookup_private(&tap_cd, unit); 1091 1092 if (sc == NULL) 1093 return ENXIO; 1094 1095 switch (cmd) { 1096 case FIONREAD: 1097 { 1098 struct ifnet *ifp = &sc->sc_ec.ec_if; 1099 struct mbuf *m; 1100 int s; 1101 1102 s = splnet(); 1103 IFQ_POLL(&ifp->if_snd, m); 1104 1105 if (m == NULL) 1106 *(int *)data = 0; 1107 else 1108 *(int *)data = m->m_pkthdr.len; 1109 splx(s); 1110 return 0; 1111 } 1112 case TIOCSPGRP: 1113 case FIOSETOWN: 1114 return fsetown(&sc->sc_pgid, cmd, data); 1115 case TIOCGPGRP: 1116 case FIOGETOWN: 1117 return fgetown(sc->sc_pgid, cmd, data); 1118 case FIOASYNC: 1119 if (*(int *)data) { 1120 if (sc->sc_sih == NULL) { 1121 sc->sc_sih = softint_establish(SOFTINT_CLOCK, 1122 tap_softintr, sc); 1123 if (sc->sc_sih == NULL) 1124 return EBUSY; /* XXX */ 1125 } 1126 sc->sc_flags |= TAP_ASYNCIO; 1127 } else { 1128 sc->sc_flags &= ~TAP_ASYNCIO; 1129 if (sc->sc_sih != NULL) { 1130 softint_disestablish(sc->sc_sih); 1131 sc->sc_sih = NULL; 1132 } 1133 } 1134 return 0; 1135 case FIONBIO: 1136 if (*(int *)data) 1137 sc->sc_flags |= TAP_NBIO; 1138 else 1139 sc->sc_flags &= ~TAP_NBIO; 1140 return 0; 1141 #ifdef OTAPGIFNAME 1142 case OTAPGIFNAME: 1143 #endif 1144 case TAPGIFNAME: 1145 { 1146 struct ifreq *ifr = (struct ifreq *)data; 1147 struct ifnet *ifp = &sc->sc_ec.ec_if; 1148 1149 strlcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1150 return 0; 1151 } 1152 default: 1153 return ENOTTY; 1154 } 1155 } 1156 1157 static int 1158 tap_cdev_poll(dev_t dev, int events, struct lwp *l) 1159 { 1160 return tap_dev_poll(minor(dev), events, l); 1161 } 1162 1163 static int 1164 tap_fops_poll(file_t *fp, int events) 1165 { 1166 return tap_dev_poll((intptr_t)fp->f_data, events, curlwp); 1167 } 1168 1169 static int 1170 tap_dev_poll(int unit, int events, struct lwp *l) 1171 { 1172 struct tap_softc *sc = 1173 device_lookup_private(&tap_cd, unit); 1174 int revents = 0; 1175 1176 if (sc == NULL) 1177 return POLLERR; 1178 1179 if (events & (POLLIN|POLLRDNORM)) { 1180 struct ifnet *ifp = &sc->sc_ec.ec_if; 1181 struct mbuf *m; 1182 int s; 1183 1184 s = splnet(); 1185 IFQ_POLL(&ifp->if_snd, m); 1186 1187 if (m != NULL) 1188 revents |= events & (POLLIN|POLLRDNORM); 1189 else { 1190 mutex_spin_enter(&sc->sc_kqlock); 1191 selrecord(l, &sc->sc_rsel); 1192 mutex_spin_exit(&sc->sc_kqlock); 1193 } 1194 splx(s); 1195 } 1196 revents |= events & (POLLOUT|POLLWRNORM); 1197 1198 return (revents); 1199 } 1200 1201 static struct filterops tap_read_filterops = { 1, NULL, tap_kqdetach, 1202 tap_kqread }; 1203 static struct filterops tap_seltrue_filterops = { 1, NULL, tap_kqdetach, 1204 filt_seltrue }; 1205 1206 static int 1207 tap_cdev_kqfilter(dev_t dev, struct knote *kn) 1208 { 1209 return tap_dev_kqfilter(minor(dev), kn); 1210 } 1211 1212 static int 1213 tap_fops_kqfilter(file_t *fp, struct knote *kn) 1214 { 1215 return tap_dev_kqfilter((intptr_t)fp->f_data, kn); 1216 } 1217 1218 static int 1219 tap_dev_kqfilter(int unit, struct knote *kn) 1220 { 1221 struct tap_softc *sc = 1222 device_lookup_private(&tap_cd, unit); 1223 1224 if (sc == NULL) 1225 return (ENXIO); 1226 1227 KERNEL_LOCK(1, NULL); 1228 switch(kn->kn_filter) { 1229 case EVFILT_READ: 1230 kn->kn_fop = &tap_read_filterops; 1231 break; 1232 case EVFILT_WRITE: 1233 kn->kn_fop = &tap_seltrue_filterops; 1234 break; 1235 default: 1236 KERNEL_UNLOCK_ONE(NULL); 1237 return (EINVAL); 1238 } 1239 1240 kn->kn_hook = sc; 1241 mutex_spin_enter(&sc->sc_kqlock); 1242 SLIST_INSERT_HEAD(&sc->sc_rsel.sel_klist, kn, kn_selnext); 1243 mutex_spin_exit(&sc->sc_kqlock); 1244 KERNEL_UNLOCK_ONE(NULL); 1245 return (0); 1246 } 1247 1248 static void 1249 tap_kqdetach(struct knote *kn) 1250 { 1251 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1252 1253 KERNEL_LOCK(1, NULL); 1254 mutex_spin_enter(&sc->sc_kqlock); 1255 SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext); 1256 mutex_spin_exit(&sc->sc_kqlock); 1257 KERNEL_UNLOCK_ONE(NULL); 1258 } 1259 1260 static int 1261 tap_kqread(struct knote *kn, long hint) 1262 { 1263 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1264 struct ifnet *ifp = &sc->sc_ec.ec_if; 1265 struct mbuf *m; 1266 int s, rv; 1267 1268 KERNEL_LOCK(1, NULL); 1269 s = splnet(); 1270 IFQ_POLL(&ifp->if_snd, m); 1271 1272 if (m == NULL) 1273 kn->kn_data = 0; 1274 else 1275 kn->kn_data = m->m_pkthdr.len; 1276 splx(s); 1277 rv = (kn->kn_data != 0 ? 1 : 0); 1278 KERNEL_UNLOCK_ONE(NULL); 1279 return rv; 1280 } 1281 1282 #if defined(COMPAT_40) || defined(MODULAR) 1283 /* 1284 * sysctl management routines 1285 * You can set the address of an interface through: 1286 * net.link.tap.tap<number> 1287 * 1288 * Note the consistent use of tap_log in order to use 1289 * sysctl_teardown at unload time. 1290 * 1291 * In the kernel you will find a lot of SYSCTL_SETUP blocks. Those 1292 * blocks register a function in a special section of the kernel 1293 * (called a link set) which is used at init_sysctl() time to cycle 1294 * through all those functions to create the kernel's sysctl tree. 1295 * 1296 * It is not possible to use link sets in a module, so the 1297 * easiest is to simply call our own setup routine at load time. 1298 * 1299 * In the SYSCTL_SETUP blocks you find in the kernel, nodes have the 1300 * CTLFLAG_PERMANENT flag, meaning they cannot be removed. Once the 1301 * whole kernel sysctl tree is built, it is not possible to add any 1302 * permanent node. 1303 * 1304 * It should be noted that we're not saving the sysctlnode pointer 1305 * we are returned when creating the "tap" node. That structure 1306 * cannot be trusted once out of the calling function, as it might 1307 * get reused. So we just save the MIB number, and always give the 1308 * full path starting from the root for later calls to sysctl_createv 1309 * and sysctl_destroyv. 1310 */ 1311 SYSCTL_SETUP(sysctl_tap_setup, "sysctl net.link.tap subtree setup") 1312 { 1313 const struct sysctlnode *node; 1314 int error = 0; 1315 1316 if ((error = sysctl_createv(clog, 0, NULL, NULL, 1317 CTLFLAG_PERMANENT, 1318 CTLTYPE_NODE, "link", NULL, 1319 NULL, 0, NULL, 0, 1320 CTL_NET, AF_LINK, CTL_EOL)) != 0) 1321 return; 1322 1323 /* 1324 * The first four parameters of sysctl_createv are for management. 1325 * 1326 * The four that follows, here starting with a '0' for the flags, 1327 * describe the node. 1328 * 1329 * The next series of four set its value, through various possible 1330 * means. 1331 * 1332 * Last but not least, the path to the node is described. That path 1333 * is relative to the given root (third argument). Here we're 1334 * starting from the root. 1335 */ 1336 if ((error = sysctl_createv(clog, 0, NULL, &node, 1337 CTLFLAG_PERMANENT, 1338 CTLTYPE_NODE, "tap", NULL, 1339 NULL, 0, NULL, 0, 1340 CTL_NET, AF_LINK, CTL_CREATE, CTL_EOL)) != 0) 1341 return; 1342 tap_node = node->sysctl_num; 1343 } 1344 1345 /* 1346 * The helper functions make Andrew Brown's interface really 1347 * shine. It makes possible to create value on the fly whether 1348 * the sysctl value is read or written. 1349 * 1350 * As shown as an example in the man page, the first step is to 1351 * create a copy of the node to have sysctl_lookup work on it. 1352 * 1353 * Here, we have more work to do than just a copy, since we have 1354 * to create the string. The first step is to collect the actual 1355 * value of the node, which is a convenient pointer to the softc 1356 * of the interface. From there we create the string and use it 1357 * as the value, but only for the *copy* of the node. 1358 * 1359 * Then we let sysctl_lookup do the magic, which consists in 1360 * setting oldp and newp as required by the operation. When the 1361 * value is read, that means that the string will be copied to 1362 * the user, and when it is written, the new value will be copied 1363 * over in the addr array. 1364 * 1365 * If newp is NULL, the user was reading the value, so we don't 1366 * have anything else to do. If a new value was written, we 1367 * have to check it. 1368 * 1369 * If it is incorrect, we can return an error and leave 'node' as 1370 * it is: since it is a copy of the actual node, the change will 1371 * be forgotten. 1372 * 1373 * Upon a correct input, we commit the change to the ifnet 1374 * structure of our interface. 1375 */ 1376 static int 1377 tap_sysctl_handler(SYSCTLFN_ARGS) 1378 { 1379 struct sysctlnode node; 1380 struct tap_softc *sc; 1381 struct ifnet *ifp; 1382 int error; 1383 size_t len; 1384 char addr[3 * ETHER_ADDR_LEN]; 1385 uint8_t enaddr[ETHER_ADDR_LEN]; 1386 1387 node = *rnode; 1388 sc = node.sysctl_data; 1389 ifp = &sc->sc_ec.ec_if; 1390 (void)ether_snprintf(addr, sizeof(addr), CLLADDR(ifp->if_sadl)); 1391 node.sysctl_data = addr; 1392 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1393 if (error || newp == NULL) 1394 return (error); 1395 1396 len = strlen(addr); 1397 if (len < 11 || len > 17) 1398 return (EINVAL); 1399 1400 /* Commit change */ 1401 if (ether_aton_r(enaddr, sizeof(enaddr), addr) != 0) 1402 return (EINVAL); 1403 if_set_sadl(ifp, enaddr, ETHER_ADDR_LEN, false); 1404 return (error); 1405 } 1406 #endif 1407