1 /* $NetBSD: if_tap.c,v 1.76 2014/05/07 22:53:34 cube 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 1.76 2014/05/07 22:53:34 cube 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_flag = D_OTHER 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 #if defined(COMPAT_40) || defined(MODULAR) 216 static int tap_lifaddr(struct ifnet *, u_long, struct ifaliasreq *); 217 #endif 218 static void tap_softintr(void *); 219 220 /* 221 * tap is a clonable interface, although it is highly unrealistic for 222 * an Ethernet device. 223 * 224 * Here are the bits needed for a clonable interface. 225 */ 226 static int tap_clone_create(struct if_clone *, int); 227 static int tap_clone_destroy(struct ifnet *); 228 229 struct if_clone tap_cloners = IF_CLONE_INITIALIZER("tap", 230 tap_clone_create, 231 tap_clone_destroy); 232 233 /* Helper functionis shared by the two cloning code paths */ 234 static struct tap_softc * tap_clone_creator(int); 235 int tap_clone_destroyer(device_t); 236 237 void 238 tapattach(int n) 239 { 240 int error; 241 242 error = config_cfattach_attach(tap_cd.cd_name, &tap_ca); 243 if (error) { 244 aprint_error("%s: unable to register cfattach\n", 245 tap_cd.cd_name); 246 (void)config_cfdriver_detach(&tap_cd); 247 return; 248 } 249 250 if_clone_attach(&tap_cloners); 251 } 252 253 /* Pretty much useless for a pseudo-device */ 254 static int 255 tap_match(device_t parent, cfdata_t cfdata, void *arg) 256 { 257 258 return (1); 259 } 260 261 void 262 tap_attach(device_t parent, device_t self, void *aux) 263 { 264 struct tap_softc *sc = device_private(self); 265 struct ifnet *ifp; 266 #if defined(COMPAT_40) || defined(MODULAR) 267 const struct sysctlnode *node; 268 int error; 269 #endif 270 uint8_t enaddr[ETHER_ADDR_LEN] = 271 { 0xf2, 0x0b, 0xa4, 0xff, 0xff, 0xff }; 272 char enaddrstr[3 * ETHER_ADDR_LEN]; 273 274 sc->sc_dev = self; 275 sc->sc_sih = NULL; 276 getnanotime(&sc->sc_btime); 277 sc->sc_atime = sc->sc_mtime = sc->sc_btime; 278 279 if (!pmf_device_register(self, NULL, NULL)) 280 aprint_error_dev(self, "couldn't establish power handler\n"); 281 282 /* 283 * In order to obtain unique initial Ethernet address on a host, 284 * do some randomisation. It's not meant for anything but avoiding 285 * hard-coding an address. 286 */ 287 cprng_fast(&enaddr[3], 3); 288 289 aprint_verbose_dev(self, "Ethernet address %s\n", 290 ether_snprintf(enaddrstr, sizeof(enaddrstr), enaddr)); 291 292 /* 293 * Why 1000baseT? Why not? You can add more. 294 * 295 * Note that there are 3 steps: init, one or several additions to 296 * list of supported media, and in the end, the selection of one 297 * of them. 298 */ 299 ifmedia_init(&sc->sc_im, 0, tap_mediachange, tap_mediastatus); 300 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T, 0, NULL); 301 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_1000_T|IFM_FDX, 0, NULL); 302 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX, 0, NULL); 303 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_100_TX|IFM_FDX, 0, NULL); 304 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T, 0, NULL); 305 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_10_T|IFM_FDX, 0, NULL); 306 ifmedia_add(&sc->sc_im, IFM_ETHER|IFM_AUTO, 0, NULL); 307 ifmedia_set(&sc->sc_im, IFM_ETHER|IFM_AUTO); 308 309 /* 310 * One should note that an interface must do multicast in order 311 * to support IPv6. 312 */ 313 ifp = &sc->sc_ec.ec_if; 314 strcpy(ifp->if_xname, device_xname(self)); 315 ifp->if_softc = sc; 316 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 317 ifp->if_ioctl = tap_ioctl; 318 ifp->if_start = tap_start; 319 ifp->if_stop = tap_stop; 320 ifp->if_init = tap_init; 321 IFQ_SET_READY(&ifp->if_snd); 322 323 sc->sc_ec.ec_capabilities = ETHERCAP_VLAN_MTU | ETHERCAP_JUMBO_MTU; 324 325 /* Those steps are mandatory for an Ethernet driver, the fisrt call 326 * being common to all network interface drivers. */ 327 if_attach(ifp); 328 ether_ifattach(ifp, enaddr); 329 330 sc->sc_flags = 0; 331 332 #if defined(COMPAT_40) || defined(MODULAR) 333 /* 334 * Add a sysctl node for that interface. 335 * 336 * The pointer transmitted is not a string, but instead a pointer to 337 * the softc structure, which we can use to build the string value on 338 * the fly in the helper function of the node. See the comments for 339 * tap_sysctl_handler for details. 340 * 341 * Usually sysctl_createv is called with CTL_CREATE as the before-last 342 * component. However, we can allocate a number ourselves, as we are 343 * the only consumer of the net.link.<iface> node. In this case, the 344 * unit number is conveniently used to number the node. CTL_CREATE 345 * would just work, too. 346 */ 347 if ((error = sysctl_createv(NULL, 0, NULL, 348 &node, CTLFLAG_READWRITE, 349 CTLTYPE_STRING, device_xname(self), NULL, 350 tap_sysctl_handler, 0, (void *)sc, 18, 351 CTL_NET, AF_LINK, tap_node, device_unit(sc->sc_dev), 352 CTL_EOL)) != 0) 353 aprint_error_dev(self, "sysctl_createv returned %d, ignoring\n", 354 error); 355 #endif 356 357 /* 358 * Initialize the two locks for the device. 359 * 360 * We need a lock here because even though the tap device can be 361 * opened only once, the file descriptor might be passed to another 362 * process, say a fork(2)ed child. 363 * 364 * The Giant saves us from most of the hassle, but since the read 365 * operation can sleep, we don't want two processes to wake up at 366 * the same moment and both try and dequeue a single packet. 367 * 368 * The queue for event listeners (used by kqueue(9), see below) has 369 * to be protected too, so use a spin lock. 370 */ 371 mutex_init(&sc->sc_rdlock, MUTEX_DEFAULT, IPL_NONE); 372 mutex_init(&sc->sc_kqlock, MUTEX_DEFAULT, IPL_VM); 373 374 selinit(&sc->sc_rsel); 375 } 376 377 /* 378 * When detaching, we do the inverse of what is done in the attach 379 * routine, in reversed order. 380 */ 381 static int 382 tap_detach(device_t self, int flags) 383 { 384 struct tap_softc *sc = device_private(self); 385 struct ifnet *ifp = &sc->sc_ec.ec_if; 386 #if defined(COMPAT_40) || defined(MODULAR) 387 int error; 388 #endif 389 int s; 390 391 sc->sc_flags |= TAP_GOING; 392 s = splnet(); 393 tap_stop(ifp, 1); 394 if_down(ifp); 395 splx(s); 396 397 if (sc->sc_sih != NULL) { 398 softint_disestablish(sc->sc_sih); 399 sc->sc_sih = NULL; 400 } 401 402 #if defined(COMPAT_40) || defined(MODULAR) 403 /* 404 * Destroying a single leaf is a very straightforward operation using 405 * sysctl_destroyv. One should be sure to always end the path with 406 * CTL_EOL. 407 */ 408 if ((error = sysctl_destroyv(NULL, CTL_NET, AF_LINK, tap_node, 409 device_unit(sc->sc_dev), CTL_EOL)) != 0) 410 aprint_error_dev(self, 411 "sysctl_destroyv returned %d, ignoring\n", error); 412 #endif 413 ether_ifdetach(ifp); 414 if_detach(ifp); 415 ifmedia_delete_instance(&sc->sc_im, IFM_INST_ANY); 416 seldestroy(&sc->sc_rsel); 417 mutex_destroy(&sc->sc_rdlock); 418 mutex_destroy(&sc->sc_kqlock); 419 420 pmf_device_deregister(self); 421 422 return (0); 423 } 424 425 /* 426 * This function is called by the ifmedia layer to notify the driver 427 * that the user requested a media change. A real driver would 428 * reconfigure the hardware. 429 */ 430 static int 431 tap_mediachange(struct ifnet *ifp) 432 { 433 return (0); 434 } 435 436 /* 437 * Here the user asks for the currently used media. 438 */ 439 static void 440 tap_mediastatus(struct ifnet *ifp, struct ifmediareq *imr) 441 { 442 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 443 imr->ifm_active = sc->sc_im.ifm_cur->ifm_media; 444 } 445 446 /* 447 * This is the function where we SEND packets. 448 * 449 * There is no 'receive' equivalent. A typical driver will get 450 * interrupts from the hardware, and from there will inject new packets 451 * into the network stack. 452 * 453 * Once handled, a packet must be freed. A real driver might not be able 454 * to fit all the pending packets into the hardware, and is allowed to 455 * return before having sent all the packets. It should then use the 456 * if_flags flag IFF_OACTIVE to notify the upper layer. 457 * 458 * There are also other flags one should check, such as IFF_PAUSE. 459 * 460 * It is our duty to make packets available to BPF listeners. 461 * 462 * You should be aware that this function is called by the Ethernet layer 463 * at splnet(). 464 * 465 * When the device is opened, we have to pass the packet(s) to the 466 * userland. For that we stay in OACTIVE mode while the userland gets 467 * the packets, and we send a signal to the processes waiting to read. 468 * 469 * wakeup(sc) is the counterpart to the tsleep call in 470 * tap_dev_read, while selnotify() is used for kevent(2) and 471 * poll(2) (which includes select(2)) listeners. 472 */ 473 static void 474 tap_start(struct ifnet *ifp) 475 { 476 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 477 struct mbuf *m0; 478 479 if ((sc->sc_flags & TAP_INUSE) == 0) { 480 /* Simply drop packets */ 481 for(;;) { 482 IFQ_DEQUEUE(&ifp->if_snd, m0); 483 if (m0 == NULL) 484 return; 485 486 ifp->if_opackets++; 487 bpf_mtap(ifp, m0); 488 489 m_freem(m0); 490 } 491 } else if (!IFQ_IS_EMPTY(&ifp->if_snd)) { 492 ifp->if_flags |= IFF_OACTIVE; 493 wakeup(sc); 494 selnotify(&sc->sc_rsel, 0, 1); 495 if (sc->sc_flags & TAP_ASYNCIO) 496 softint_schedule(sc->sc_sih); 497 } 498 } 499 500 static void 501 tap_softintr(void *cookie) 502 { 503 struct tap_softc *sc; 504 struct ifnet *ifp; 505 int a, b; 506 507 sc = cookie; 508 509 if (sc->sc_flags & TAP_ASYNCIO) { 510 ifp = &sc->sc_ec.ec_if; 511 if (ifp->if_flags & IFF_RUNNING) { 512 a = POLL_IN; 513 b = POLLIN|POLLRDNORM; 514 } else { 515 a = POLL_HUP; 516 b = 0; 517 } 518 fownsignal(sc->sc_pgid, SIGIO, a, b, NULL); 519 } 520 } 521 522 /* 523 * A typical driver will only contain the following handlers for 524 * ioctl calls, except SIOCSIFPHYADDR. 525 * The latter is a hack I used to set the Ethernet address of the 526 * faked device. 527 * 528 * Note that both ifmedia_ioctl() and ether_ioctl() have to be 529 * called under splnet(). 530 */ 531 static int 532 tap_ioctl(struct ifnet *ifp, u_long cmd, void *data) 533 { 534 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 535 struct ifreq *ifr = (struct ifreq *)data; 536 int s, error; 537 538 s = splnet(); 539 540 switch (cmd) { 541 #ifdef OSIOCSIFMEDIA 542 case OSIOCSIFMEDIA: 543 #endif 544 case SIOCSIFMEDIA: 545 case SIOCGIFMEDIA: 546 error = ifmedia_ioctl(ifp, ifr, &sc->sc_im, cmd); 547 break; 548 #if defined(COMPAT_40) || defined(MODULAR) 549 case SIOCSIFPHYADDR: 550 error = tap_lifaddr(ifp, cmd, (struct ifaliasreq *)data); 551 break; 552 #endif 553 default: 554 error = ether_ioctl(ifp, cmd, data); 555 if (error == ENETRESET) 556 error = 0; 557 break; 558 } 559 560 splx(s); 561 562 return (error); 563 } 564 565 #if defined(COMPAT_40) || defined(MODULAR) 566 /* 567 * Helper function to set Ethernet address. This has been replaced by 568 * the generic SIOCALIFADDR ioctl on a PF_LINK socket. 569 */ 570 static int 571 tap_lifaddr(struct ifnet *ifp, u_long cmd, struct ifaliasreq *ifra) 572 { 573 const struct sockaddr *sa = &ifra->ifra_addr; 574 575 if (sa->sa_family != AF_LINK) 576 return (EINVAL); 577 578 if_set_sadl(ifp, sa->sa_data, ETHER_ADDR_LEN, false); 579 580 return (0); 581 } 582 #endif 583 584 /* 585 * _init() would typically be called when an interface goes up, 586 * meaning it should configure itself into the state in which it 587 * can send packets. 588 */ 589 static int 590 tap_init(struct ifnet *ifp) 591 { 592 ifp->if_flags |= IFF_RUNNING; 593 594 tap_start(ifp); 595 596 return (0); 597 } 598 599 /* 600 * _stop() is called when an interface goes down. It is our 601 * responsability to validate that state by clearing the 602 * IFF_RUNNING flag. 603 * 604 * We have to wake up all the sleeping processes to have the pending 605 * read requests cancelled. 606 */ 607 static void 608 tap_stop(struct ifnet *ifp, int disable) 609 { 610 struct tap_softc *sc = (struct tap_softc *)ifp->if_softc; 611 612 ifp->if_flags &= ~IFF_RUNNING; 613 wakeup(sc); 614 selnotify(&sc->sc_rsel, 0, 1); 615 if (sc->sc_flags & TAP_ASYNCIO) 616 softint_schedule(sc->sc_sih); 617 } 618 619 /* 620 * The 'create' command of ifconfig can be used to create 621 * any numbered instance of a given device. Thus we have to 622 * make sure we have enough room in cd_devs to create the 623 * user-specified instance. config_attach_pseudo will do this 624 * for us. 625 */ 626 static int 627 tap_clone_create(struct if_clone *ifc, int unit) 628 { 629 if (tap_clone_creator(unit) == NULL) { 630 aprint_error("%s%d: unable to attach an instance\n", 631 tap_cd.cd_name, unit); 632 return (ENXIO); 633 } 634 635 return (0); 636 } 637 638 /* 639 * tap(4) can be cloned by two ways: 640 * using 'ifconfig tap0 create', which will use the network 641 * interface cloning API, and call tap_clone_create above. 642 * opening the cloning device node, whose minor number is TAP_CLONER. 643 * See below for an explanation on how this part work. 644 */ 645 static struct tap_softc * 646 tap_clone_creator(int unit) 647 { 648 struct cfdata *cf; 649 650 cf = malloc(sizeof(*cf), M_DEVBUF, M_WAITOK); 651 cf->cf_name = tap_cd.cd_name; 652 cf->cf_atname = tap_ca.ca_name; 653 if (unit == -1) { 654 /* let autoconf find the first free one */ 655 cf->cf_unit = 0; 656 cf->cf_fstate = FSTATE_STAR; 657 } else { 658 cf->cf_unit = unit; 659 cf->cf_fstate = FSTATE_NOTFOUND; 660 } 661 662 return device_private(config_attach_pseudo(cf)); 663 } 664 665 /* 666 * The clean design of if_clone and autoconf(9) makes that part 667 * really straightforward. The second argument of config_detach 668 * means neither QUIET nor FORCED. 669 */ 670 static int 671 tap_clone_destroy(struct ifnet *ifp) 672 { 673 struct tap_softc *sc = ifp->if_softc; 674 675 return tap_clone_destroyer(sc->sc_dev); 676 } 677 678 int 679 tap_clone_destroyer(device_t dev) 680 { 681 cfdata_t cf = device_cfdata(dev); 682 int error; 683 684 if ((error = config_detach(dev, 0)) != 0) 685 aprint_error_dev(dev, "unable to detach instance\n"); 686 free(cf, M_DEVBUF); 687 688 return (error); 689 } 690 691 /* 692 * tap(4) is a bit of an hybrid device. It can be used in two different 693 * ways: 694 * 1. ifconfig tapN create, then use /dev/tapN to read/write off it. 695 * 2. open /dev/tap, get a new interface created and read/write off it. 696 * That interface is destroyed when the process that had it created exits. 697 * 698 * The first way is managed by the cdevsw structure, and you access interfaces 699 * through a (major, minor) mapping: tap4 is obtained by the minor number 700 * 4. The entry points for the cdevsw interface are prefixed by tap_cdev_. 701 * 702 * The second way is the so-called "cloning" device. It's a special minor 703 * number (chosen as the maximal number, to allow as much tap devices as 704 * possible). The user first opens the cloner (e.g., /dev/tap), and that 705 * call ends in tap_cdev_open. The actual place where it is handled is 706 * tap_dev_cloner. 707 * 708 * An tap device cannot be opened more than once at a time, so the cdevsw 709 * part of open() does nothing but noting that the interface is being used and 710 * hence ready to actually handle packets. 711 */ 712 713 static int 714 tap_cdev_open(dev_t dev, int flags, int fmt, struct lwp *l) 715 { 716 struct tap_softc *sc; 717 718 if (minor(dev) == TAP_CLONER) 719 return tap_dev_cloner(l); 720 721 sc = device_lookup_private(&tap_cd, minor(dev)); 722 if (sc == NULL) 723 return (ENXIO); 724 725 /* The device can only be opened once */ 726 if (sc->sc_flags & TAP_INUSE) 727 return (EBUSY); 728 sc->sc_flags |= TAP_INUSE; 729 return (0); 730 } 731 732 /* 733 * There are several kinds of cloning devices, and the most simple is the one 734 * tap(4) uses. What it does is change the file descriptor with a new one, 735 * with its own fileops structure (which maps to the various read, write, 736 * ioctl functions). It starts allocating a new file descriptor with falloc, 737 * then actually creates the new tap devices. 738 * 739 * Once those two steps are successful, we can re-wire the existing file 740 * descriptor to its new self. This is done with fdclone(): it fills the fp 741 * structure as needed (notably f_data gets filled with the fifth parameter 742 * passed, the unit of the tap device which will allows us identifying the 743 * device later), and returns EMOVEFD. 744 * 745 * That magic value is interpreted by sys_open() which then replaces the 746 * current file descriptor by the new one (through a magic member of struct 747 * lwp, l_dupfd). 748 * 749 * The tap device is flagged as being busy since it otherwise could be 750 * externally accessed through the corresponding device node with the cdevsw 751 * interface. 752 */ 753 754 static int 755 tap_dev_cloner(struct lwp *l) 756 { 757 struct tap_softc *sc; 758 file_t *fp; 759 int error, fd; 760 761 if ((error = fd_allocfile(&fp, &fd)) != 0) 762 return (error); 763 764 if ((sc = tap_clone_creator(-1)) == NULL) { 765 fd_abort(curproc, fp, fd); 766 return (ENXIO); 767 } 768 769 sc->sc_flags |= TAP_INUSE; 770 771 return fd_clone(fp, fd, FREAD|FWRITE, &tap_fileops, 772 (void *)(intptr_t)device_unit(sc->sc_dev)); 773 } 774 775 /* 776 * While all other operations (read, write, ioctl, poll and kqfilter) are 777 * really the same whether we are in cdevsw or fileops mode, the close() 778 * function is slightly different in the two cases. 779 * 780 * As for the other, the core of it is shared in tap_dev_close. What 781 * it does is sufficient for the cdevsw interface, but the cloning interface 782 * needs another thing: the interface is destroyed when the processes that 783 * created it closes it. 784 */ 785 static int 786 tap_cdev_close(dev_t dev, int flags, int fmt, 787 struct lwp *l) 788 { 789 struct tap_softc *sc = 790 device_lookup_private(&tap_cd, minor(dev)); 791 792 if (sc == NULL) 793 return (ENXIO); 794 795 return tap_dev_close(sc); 796 } 797 798 /* 799 * It might happen that the administrator used ifconfig to externally destroy 800 * the interface. In that case, tap_fops_close will be called while 801 * tap_detach is already happening. If we called it again from here, we 802 * would dead lock. TAP_GOING ensures that this situation doesn't happen. 803 */ 804 static int 805 tap_fops_close(file_t *fp) 806 { 807 int unit = (intptr_t)fp->f_data; 808 struct tap_softc *sc; 809 int error; 810 811 sc = device_lookup_private(&tap_cd, unit); 812 if (sc == NULL) 813 return (ENXIO); 814 815 /* tap_dev_close currently always succeeds, but it might not 816 * always be the case. */ 817 KERNEL_LOCK(1, NULL); 818 if ((error = tap_dev_close(sc)) != 0) { 819 KERNEL_UNLOCK_ONE(NULL); 820 return (error); 821 } 822 823 /* Destroy the device now that it is no longer useful, 824 * unless it's already being destroyed. */ 825 if ((sc->sc_flags & TAP_GOING) != 0) { 826 KERNEL_UNLOCK_ONE(NULL); 827 return (0); 828 } 829 830 error = tap_clone_destroyer(sc->sc_dev); 831 KERNEL_UNLOCK_ONE(NULL); 832 return error; 833 } 834 835 static int 836 tap_dev_close(struct tap_softc *sc) 837 { 838 struct ifnet *ifp; 839 int s; 840 841 s = splnet(); 842 /* Let tap_start handle packets again */ 843 ifp = &sc->sc_ec.ec_if; 844 ifp->if_flags &= ~IFF_OACTIVE; 845 846 /* Purge output queue */ 847 if (!(IFQ_IS_EMPTY(&ifp->if_snd))) { 848 struct mbuf *m; 849 850 for (;;) { 851 IFQ_DEQUEUE(&ifp->if_snd, m); 852 if (m == NULL) 853 break; 854 855 ifp->if_opackets++; 856 bpf_mtap(ifp, m); 857 m_freem(m); 858 } 859 } 860 splx(s); 861 862 if (sc->sc_sih != NULL) { 863 softint_disestablish(sc->sc_sih); 864 sc->sc_sih = NULL; 865 } 866 sc->sc_flags &= ~(TAP_INUSE | TAP_ASYNCIO); 867 868 return (0); 869 } 870 871 static int 872 tap_cdev_read(dev_t dev, struct uio *uio, int flags) 873 { 874 return tap_dev_read(minor(dev), uio, flags); 875 } 876 877 static int 878 tap_fops_read(file_t *fp, off_t *offp, struct uio *uio, 879 kauth_cred_t cred, int flags) 880 { 881 int error; 882 883 KERNEL_LOCK(1, NULL); 884 error = tap_dev_read((intptr_t)fp->f_data, uio, flags); 885 KERNEL_UNLOCK_ONE(NULL); 886 return error; 887 } 888 889 static int 890 tap_dev_read(int unit, struct uio *uio, int flags) 891 { 892 struct tap_softc *sc = 893 device_lookup_private(&tap_cd, unit); 894 struct ifnet *ifp; 895 struct mbuf *m, *n; 896 int error = 0, s; 897 898 if (sc == NULL) 899 return (ENXIO); 900 901 getnanotime(&sc->sc_atime); 902 903 ifp = &sc->sc_ec.ec_if; 904 if ((ifp->if_flags & IFF_UP) == 0) 905 return (EHOSTDOWN); 906 907 /* 908 * In the TAP_NBIO case, we have to make sure we won't be sleeping 909 */ 910 if ((sc->sc_flags & TAP_NBIO) != 0) { 911 if (!mutex_tryenter(&sc->sc_rdlock)) 912 return (EWOULDBLOCK); 913 } else { 914 mutex_enter(&sc->sc_rdlock); 915 } 916 917 s = splnet(); 918 if (IFQ_IS_EMPTY(&ifp->if_snd)) { 919 ifp->if_flags &= ~IFF_OACTIVE; 920 /* 921 * We must release the lock before sleeping, and re-acquire it 922 * after. 923 */ 924 mutex_exit(&sc->sc_rdlock); 925 if (sc->sc_flags & TAP_NBIO) 926 error = EWOULDBLOCK; 927 else 928 error = tsleep(sc, PSOCK|PCATCH, "tap", 0); 929 splx(s); 930 931 if (error != 0) 932 return (error); 933 /* The device might have been downed */ 934 if ((ifp->if_flags & IFF_UP) == 0) 935 return (EHOSTDOWN); 936 if ((sc->sc_flags & TAP_NBIO)) { 937 if (!mutex_tryenter(&sc->sc_rdlock)) 938 return (EWOULDBLOCK); 939 } else { 940 mutex_enter(&sc->sc_rdlock); 941 } 942 s = splnet(); 943 } 944 945 IFQ_DEQUEUE(&ifp->if_snd, m); 946 ifp->if_flags &= ~IFF_OACTIVE; 947 splx(s); 948 if (m == NULL) { 949 error = 0; 950 goto out; 951 } 952 953 ifp->if_opackets++; 954 bpf_mtap(ifp, m); 955 956 /* 957 * One read is one packet. 958 */ 959 do { 960 error = uiomove(mtod(m, void *), 961 min(m->m_len, uio->uio_resid), uio); 962 MFREE(m, n); 963 m = n; 964 } while (m != NULL && uio->uio_resid > 0 && error == 0); 965 966 if (m != NULL) 967 m_freem(m); 968 969 out: 970 mutex_exit(&sc->sc_rdlock); 971 return (error); 972 } 973 974 static int 975 tap_fops_stat(file_t *fp, struct stat *st) 976 { 977 int error = 0; 978 struct tap_softc *sc; 979 int unit = (uintptr_t)fp->f_data; 980 981 (void)memset(st, 0, sizeof(*st)); 982 983 KERNEL_LOCK(1, NULL); 984 sc = device_lookup_private(&tap_cd, unit); 985 if (sc == NULL) { 986 error = ENXIO; 987 goto out; 988 } 989 990 st->st_dev = makedev(cdevsw_lookup_major(&tap_cdevsw), unit); 991 st->st_atimespec = sc->sc_atime; 992 st->st_mtimespec = sc->sc_mtime; 993 st->st_ctimespec = st->st_birthtimespec = sc->sc_btime; 994 st->st_uid = kauth_cred_geteuid(fp->f_cred); 995 st->st_gid = kauth_cred_getegid(fp->f_cred); 996 out: 997 KERNEL_UNLOCK_ONE(NULL); 998 return error; 999 } 1000 1001 static int 1002 tap_cdev_write(dev_t dev, struct uio *uio, int flags) 1003 { 1004 return tap_dev_write(minor(dev), uio, flags); 1005 } 1006 1007 static int 1008 tap_fops_write(file_t *fp, off_t *offp, struct uio *uio, 1009 kauth_cred_t cred, int flags) 1010 { 1011 int error; 1012 1013 KERNEL_LOCK(1, NULL); 1014 error = tap_dev_write((intptr_t)fp->f_data, uio, flags); 1015 KERNEL_UNLOCK_ONE(NULL); 1016 return error; 1017 } 1018 1019 static int 1020 tap_dev_write(int unit, struct uio *uio, int flags) 1021 { 1022 struct tap_softc *sc = 1023 device_lookup_private(&tap_cd, unit); 1024 struct ifnet *ifp; 1025 struct mbuf *m, **mp; 1026 int error = 0; 1027 int s; 1028 1029 if (sc == NULL) 1030 return (ENXIO); 1031 1032 getnanotime(&sc->sc_mtime); 1033 ifp = &sc->sc_ec.ec_if; 1034 1035 /* One write, one packet, that's the rule */ 1036 MGETHDR(m, M_DONTWAIT, MT_DATA); 1037 if (m == NULL) { 1038 ifp->if_ierrors++; 1039 return (ENOBUFS); 1040 } 1041 m->m_pkthdr.len = uio->uio_resid; 1042 1043 mp = &m; 1044 while (error == 0 && uio->uio_resid > 0) { 1045 if (*mp != m) { 1046 MGET(*mp, M_DONTWAIT, MT_DATA); 1047 if (*mp == NULL) { 1048 error = ENOBUFS; 1049 break; 1050 } 1051 } 1052 (*mp)->m_len = min(MHLEN, uio->uio_resid); 1053 error = uiomove(mtod(*mp, void *), (*mp)->m_len, uio); 1054 mp = &(*mp)->m_next; 1055 } 1056 if (error) { 1057 ifp->if_ierrors++; 1058 m_freem(m); 1059 return (error); 1060 } 1061 1062 ifp->if_ipackets++; 1063 m->m_pkthdr.rcvif = ifp; 1064 1065 bpf_mtap(ifp, m); 1066 s = splnet(); 1067 (*ifp->if_input)(ifp, m); 1068 splx(s); 1069 1070 return (0); 1071 } 1072 1073 static int 1074 tap_cdev_ioctl(dev_t dev, u_long cmd, void *data, int flags, 1075 struct lwp *l) 1076 { 1077 return tap_dev_ioctl(minor(dev), cmd, data, l); 1078 } 1079 1080 static int 1081 tap_fops_ioctl(file_t *fp, u_long cmd, void *data) 1082 { 1083 return tap_dev_ioctl((intptr_t)fp->f_data, cmd, data, curlwp); 1084 } 1085 1086 static int 1087 tap_dev_ioctl(int unit, u_long cmd, void *data, struct lwp *l) 1088 { 1089 struct tap_softc *sc = device_lookup_private(&tap_cd, unit); 1090 1091 if (sc == NULL) 1092 return ENXIO; 1093 1094 switch (cmd) { 1095 case FIONREAD: 1096 { 1097 struct ifnet *ifp = &sc->sc_ec.ec_if; 1098 struct mbuf *m; 1099 int s; 1100 1101 s = splnet(); 1102 IFQ_POLL(&ifp->if_snd, m); 1103 1104 if (m == NULL) 1105 *(int *)data = 0; 1106 else 1107 *(int *)data = m->m_pkthdr.len; 1108 splx(s); 1109 return 0; 1110 } 1111 case TIOCSPGRP: 1112 case FIOSETOWN: 1113 return fsetown(&sc->sc_pgid, cmd, data); 1114 case TIOCGPGRP: 1115 case FIOGETOWN: 1116 return fgetown(sc->sc_pgid, cmd, data); 1117 case FIOASYNC: 1118 if (*(int *)data) { 1119 if (sc->sc_sih == NULL) { 1120 sc->sc_sih = softint_establish(SOFTINT_CLOCK, 1121 tap_softintr, sc); 1122 if (sc->sc_sih == NULL) 1123 return EBUSY; /* XXX */ 1124 } 1125 sc->sc_flags |= TAP_ASYNCIO; 1126 } else { 1127 sc->sc_flags &= ~TAP_ASYNCIO; 1128 if (sc->sc_sih != NULL) { 1129 softint_disestablish(sc->sc_sih); 1130 sc->sc_sih = NULL; 1131 } 1132 } 1133 return 0; 1134 case FIONBIO: 1135 if (*(int *)data) 1136 sc->sc_flags |= TAP_NBIO; 1137 else 1138 sc->sc_flags &= ~TAP_NBIO; 1139 return 0; 1140 #ifdef OTAPGIFNAME 1141 case OTAPGIFNAME: 1142 #endif 1143 case TAPGIFNAME: 1144 { 1145 struct ifreq *ifr = (struct ifreq *)data; 1146 struct ifnet *ifp = &sc->sc_ec.ec_if; 1147 1148 strlcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1149 return 0; 1150 } 1151 default: 1152 return ENOTTY; 1153 } 1154 } 1155 1156 static int 1157 tap_cdev_poll(dev_t dev, int events, struct lwp *l) 1158 { 1159 return tap_dev_poll(minor(dev), events, l); 1160 } 1161 1162 static int 1163 tap_fops_poll(file_t *fp, int events) 1164 { 1165 return tap_dev_poll((intptr_t)fp->f_data, events, curlwp); 1166 } 1167 1168 static int 1169 tap_dev_poll(int unit, int events, struct lwp *l) 1170 { 1171 struct tap_softc *sc = 1172 device_lookup_private(&tap_cd, unit); 1173 int revents = 0; 1174 1175 if (sc == NULL) 1176 return POLLERR; 1177 1178 if (events & (POLLIN|POLLRDNORM)) { 1179 struct ifnet *ifp = &sc->sc_ec.ec_if; 1180 struct mbuf *m; 1181 int s; 1182 1183 s = splnet(); 1184 IFQ_POLL(&ifp->if_snd, m); 1185 1186 if (m != NULL) 1187 revents |= events & (POLLIN|POLLRDNORM); 1188 else { 1189 mutex_spin_enter(&sc->sc_kqlock); 1190 selrecord(l, &sc->sc_rsel); 1191 mutex_spin_exit(&sc->sc_kqlock); 1192 } 1193 splx(s); 1194 } 1195 revents |= events & (POLLOUT|POLLWRNORM); 1196 1197 return (revents); 1198 } 1199 1200 static struct filterops tap_read_filterops = { 1, NULL, tap_kqdetach, 1201 tap_kqread }; 1202 static struct filterops tap_seltrue_filterops = { 1, NULL, tap_kqdetach, 1203 filt_seltrue }; 1204 1205 static int 1206 tap_cdev_kqfilter(dev_t dev, struct knote *kn) 1207 { 1208 return tap_dev_kqfilter(minor(dev), kn); 1209 } 1210 1211 static int 1212 tap_fops_kqfilter(file_t *fp, struct knote *kn) 1213 { 1214 return tap_dev_kqfilter((intptr_t)fp->f_data, kn); 1215 } 1216 1217 static int 1218 tap_dev_kqfilter(int unit, struct knote *kn) 1219 { 1220 struct tap_softc *sc = 1221 device_lookup_private(&tap_cd, unit); 1222 1223 if (sc == NULL) 1224 return (ENXIO); 1225 1226 KERNEL_LOCK(1, NULL); 1227 switch(kn->kn_filter) { 1228 case EVFILT_READ: 1229 kn->kn_fop = &tap_read_filterops; 1230 break; 1231 case EVFILT_WRITE: 1232 kn->kn_fop = &tap_seltrue_filterops; 1233 break; 1234 default: 1235 KERNEL_UNLOCK_ONE(NULL); 1236 return (EINVAL); 1237 } 1238 1239 kn->kn_hook = sc; 1240 mutex_spin_enter(&sc->sc_kqlock); 1241 SLIST_INSERT_HEAD(&sc->sc_rsel.sel_klist, kn, kn_selnext); 1242 mutex_spin_exit(&sc->sc_kqlock); 1243 KERNEL_UNLOCK_ONE(NULL); 1244 return (0); 1245 } 1246 1247 static void 1248 tap_kqdetach(struct knote *kn) 1249 { 1250 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1251 1252 KERNEL_LOCK(1, NULL); 1253 mutex_spin_enter(&sc->sc_kqlock); 1254 SLIST_REMOVE(&sc->sc_rsel.sel_klist, kn, knote, kn_selnext); 1255 mutex_spin_exit(&sc->sc_kqlock); 1256 KERNEL_UNLOCK_ONE(NULL); 1257 } 1258 1259 static int 1260 tap_kqread(struct knote *kn, long hint) 1261 { 1262 struct tap_softc *sc = (struct tap_softc *)kn->kn_hook; 1263 struct ifnet *ifp = &sc->sc_ec.ec_if; 1264 struct mbuf *m; 1265 int s, rv; 1266 1267 KERNEL_LOCK(1, NULL); 1268 s = splnet(); 1269 IFQ_POLL(&ifp->if_snd, m); 1270 1271 if (m == NULL) 1272 kn->kn_data = 0; 1273 else 1274 kn->kn_data = m->m_pkthdr.len; 1275 splx(s); 1276 rv = (kn->kn_data != 0 ? 1 : 0); 1277 KERNEL_UNLOCK_ONE(NULL); 1278 return rv; 1279 } 1280 1281 #if defined(COMPAT_40) || defined(MODULAR) 1282 /* 1283 * sysctl management routines 1284 * You can set the address of an interface through: 1285 * net.link.tap.tap<number> 1286 * 1287 * Note the consistent use of tap_log in order to use 1288 * sysctl_teardown at unload time. 1289 * 1290 * In the kernel you will find a lot of SYSCTL_SETUP blocks. Those 1291 * blocks register a function in a special section of the kernel 1292 * (called a link set) which is used at init_sysctl() time to cycle 1293 * through all those functions to create the kernel's sysctl tree. 1294 * 1295 * It is not possible to use link sets in a module, so the 1296 * easiest is to simply call our own setup routine at load time. 1297 * 1298 * In the SYSCTL_SETUP blocks you find in the kernel, nodes have the 1299 * CTLFLAG_PERMANENT flag, meaning they cannot be removed. Once the 1300 * whole kernel sysctl tree is built, it is not possible to add any 1301 * permanent node. 1302 * 1303 * It should be noted that we're not saving the sysctlnode pointer 1304 * we are returned when creating the "tap" node. That structure 1305 * cannot be trusted once out of the calling function, as it might 1306 * get reused. So we just save the MIB number, and always give the 1307 * full path starting from the root for later calls to sysctl_createv 1308 * and sysctl_destroyv. 1309 */ 1310 SYSCTL_SETUP(sysctl_tap_setup, "sysctl net.link.tap subtree setup") 1311 { 1312 const struct sysctlnode *node; 1313 int error = 0; 1314 1315 if ((error = sysctl_createv(clog, 0, NULL, NULL, 1316 CTLFLAG_PERMANENT, 1317 CTLTYPE_NODE, "link", NULL, 1318 NULL, 0, NULL, 0, 1319 CTL_NET, AF_LINK, CTL_EOL)) != 0) 1320 return; 1321 1322 /* 1323 * The first four parameters of sysctl_createv are for management. 1324 * 1325 * The four that follows, here starting with a '0' for the flags, 1326 * describe the node. 1327 * 1328 * The next series of four set its value, through various possible 1329 * means. 1330 * 1331 * Last but not least, the path to the node is described. That path 1332 * is relative to the given root (third argument). Here we're 1333 * starting from the root. 1334 */ 1335 if ((error = sysctl_createv(clog, 0, NULL, &node, 1336 CTLFLAG_PERMANENT, 1337 CTLTYPE_NODE, "tap", NULL, 1338 NULL, 0, NULL, 0, 1339 CTL_NET, AF_LINK, CTL_CREATE, CTL_EOL)) != 0) 1340 return; 1341 tap_node = node->sysctl_num; 1342 } 1343 1344 /* 1345 * The helper functions make Andrew Brown's interface really 1346 * shine. It makes possible to create value on the fly whether 1347 * the sysctl value is read or written. 1348 * 1349 * As shown as an example in the man page, the first step is to 1350 * create a copy of the node to have sysctl_lookup work on it. 1351 * 1352 * Here, we have more work to do than just a copy, since we have 1353 * to create the string. The first step is to collect the actual 1354 * value of the node, which is a convenient pointer to the softc 1355 * of the interface. From there we create the string and use it 1356 * as the value, but only for the *copy* of the node. 1357 * 1358 * Then we let sysctl_lookup do the magic, which consists in 1359 * setting oldp and newp as required by the operation. When the 1360 * value is read, that means that the string will be copied to 1361 * the user, and when it is written, the new value will be copied 1362 * over in the addr array. 1363 * 1364 * If newp is NULL, the user was reading the value, so we don't 1365 * have anything else to do. If a new value was written, we 1366 * have to check it. 1367 * 1368 * If it is incorrect, we can return an error and leave 'node' as 1369 * it is: since it is a copy of the actual node, the change will 1370 * be forgotten. 1371 * 1372 * Upon a correct input, we commit the change to the ifnet 1373 * structure of our interface. 1374 */ 1375 static int 1376 tap_sysctl_handler(SYSCTLFN_ARGS) 1377 { 1378 struct sysctlnode node; 1379 struct tap_softc *sc; 1380 struct ifnet *ifp; 1381 int error; 1382 size_t len; 1383 char addr[3 * ETHER_ADDR_LEN]; 1384 uint8_t enaddr[ETHER_ADDR_LEN]; 1385 1386 node = *rnode; 1387 sc = node.sysctl_data; 1388 ifp = &sc->sc_ec.ec_if; 1389 (void)ether_snprintf(addr, sizeof(addr), CLLADDR(ifp->if_sadl)); 1390 node.sysctl_data = addr; 1391 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1392 if (error || newp == NULL) 1393 return (error); 1394 1395 len = strlen(addr); 1396 if (len < 11 || len > 17) 1397 return (EINVAL); 1398 1399 /* Commit change */ 1400 if (ether_aton_r(enaddr, sizeof(enaddr), addr) != 0) 1401 return (EINVAL); 1402 if_set_sadl(ifp, enaddr, ETHER_ADDR_LEN, false); 1403 return (error); 1404 } 1405 #endif 1406