if_shmem.c revision 1.57
1 /* $NetBSD: if_shmem.c,v 1.57 2013/07/22 21:12:03 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 2009, 2010 Antti Kantee. All Rights Reserved. 5 * 6 * Development of this software was supported by The Nokia Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 18 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __KERNEL_RCSID(0, "$NetBSD: if_shmem.c,v 1.57 2013/07/22 21:12:03 pooka Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/atomic.h> 35 #include <sys/fcntl.h> 36 #include <sys/kmem.h> 37 #include <sys/kthread.h> 38 #include <sys/lock.h> 39 #include <sys/vmem.h> 40 #include <sys/cprng.h> 41 42 #include <net/bpf.h> 43 #include <net/if.h> 44 #include <net/if_dl.h> 45 #include <net/if_ether.h> 46 47 #include <netinet/in.h> 48 #include <netinet/in_var.h> 49 50 #include <rump/rump.h> 51 #include <rump/rumpuser.h> 52 53 #include "rump_private.h" 54 #include "rump_net_private.h" 55 #include "rumpcomp_user.h" 56 57 static int shmif_clone(struct if_clone *, int); 58 static int shmif_unclone(struct ifnet *); 59 60 struct if_clone shmif_cloner = 61 IF_CLONE_INITIALIZER("shmif", shmif_clone, shmif_unclone); 62 63 /* 64 * Do r/w prefault for backend pages when attaching the interface. 65 * At least logically thinking improves performance (although no 66 * mlocking is done, so they might go away). 67 */ 68 #define PREFAULT_RW 69 70 /* 71 * A virtual ethernet interface which uses shared memory from a 72 * memory mapped file as the bus. 73 */ 74 75 static int shmif_init(struct ifnet *); 76 static int shmif_ioctl(struct ifnet *, u_long, void *); 77 static void shmif_start(struct ifnet *); 78 static void shmif_stop(struct ifnet *, int); 79 80 #include "shmifvar.h" 81 82 struct shmif_sc { 83 struct ethercom sc_ec; 84 struct shmif_mem *sc_busmem; 85 int sc_memfd; 86 int sc_kq; 87 int sc_unit; 88 89 char *sc_backfile; 90 size_t sc_backfilelen; 91 92 uint64_t sc_devgen; 93 uint32_t sc_nextpacket; 94 95 kmutex_t sc_mtx; 96 kcondvar_t sc_cv; 97 98 struct lwp *sc_rcvl; 99 bool sc_dying; 100 }; 101 102 static const uint32_t busversion = SHMIF_VERSION; 103 104 static void shmif_rcv(void *); 105 106 #define LOCK_UNLOCKED 0 107 #define LOCK_LOCKED 1 108 #define LOCK_COOLDOWN 1001 109 110 vmem_t *shmif_units; 111 112 static void 113 dowakeup(struct shmif_sc *sc) 114 { 115 struct rumpuser_iovec iov; 116 uint32_t ver = SHMIF_VERSION; 117 size_t n; 118 119 iov.iov_base = &ver; 120 iov.iov_len = sizeof(ver); 121 rumpuser_iovwrite(sc->sc_memfd, &iov, 1, IFMEM_WAKEUP, &n); 122 } 123 124 /* 125 * This locking needs work and will misbehave severely if: 126 * 1) the backing memory has to be paged in 127 * 2) some lockholder exits while holding the lock 128 */ 129 static void 130 shmif_lockbus(struct shmif_mem *busmem) 131 { 132 int i = 0; 133 134 while (__predict_false(atomic_cas_32(&busmem->shm_lock, 135 LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)) { 136 if (__predict_false(++i > LOCK_COOLDOWN)) { 137 /* wait 1ms */ 138 rumpuser_clock_sleep(RUMPUSER_CLOCK_RELWALL, 139 0, 1000*1000); 140 i = 0; 141 } 142 continue; 143 } 144 membar_enter(); 145 } 146 147 static void 148 shmif_unlockbus(struct shmif_mem *busmem) 149 { 150 unsigned int old; 151 152 membar_exit(); 153 old = atomic_swap_32(&busmem->shm_lock, LOCK_UNLOCKED); 154 KASSERT(old == LOCK_LOCKED); 155 } 156 157 static int 158 allocif(int unit, struct shmif_sc **scp) 159 { 160 uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 }; 161 struct shmif_sc *sc; 162 struct ifnet *ifp; 163 uint32_t randnum; 164 int error; 165 166 randnum = cprng_fast32(); 167 memcpy(&enaddr[2], &randnum, sizeof(randnum)); 168 169 sc = kmem_zalloc(sizeof(*sc), KM_SLEEP); 170 sc->sc_memfd = -1; 171 sc->sc_unit = unit; 172 173 ifp = &sc->sc_ec.ec_if; 174 175 sprintf(ifp->if_xname, "shmif%d", unit); 176 ifp->if_softc = sc; 177 ifp->if_flags = IFF_BROADCAST | IFF_MULTICAST; 178 ifp->if_init = shmif_init; 179 ifp->if_ioctl = shmif_ioctl; 180 ifp->if_start = shmif_start; 181 ifp->if_stop = shmif_stop; 182 ifp->if_mtu = ETHERMTU; 183 ifp->if_dlt = DLT_EN10MB; 184 185 mutex_init(&sc->sc_mtx, MUTEX_DEFAULT, IPL_NONE); 186 cv_init(&sc->sc_cv, "shmifcv"); 187 188 if_attach(ifp); 189 ether_ifattach(ifp, enaddr); 190 191 aprint_verbose("shmif%d: Ethernet address %s\n", 192 unit, ether_sprintf(enaddr)); 193 194 if (scp) 195 *scp = sc; 196 197 error = 0; 198 if (rump_threads) { 199 error = kthread_create(PRI_NONE, 200 KTHREAD_MPSAFE | KTHREAD_MUSTJOIN, NULL, 201 shmif_rcv, ifp, &sc->sc_rcvl, "shmif"); 202 } else { 203 printf("WARNING: threads not enabled, shmif NOT working\n"); 204 } 205 206 if (error) { 207 shmif_unclone(ifp); 208 } 209 210 return error; 211 } 212 213 static int 214 initbackend(struct shmif_sc *sc, int memfd) 215 { 216 volatile uint8_t v; 217 volatile uint8_t *p; 218 void *mem; 219 int error; 220 221 error = rumpcomp_shmif_mmap(memfd, BUSMEM_SIZE, &mem); 222 if (error) 223 return error; 224 sc->sc_busmem = mem; 225 226 if (sc->sc_busmem->shm_magic 227 && sc->sc_busmem->shm_magic != SHMIF_MAGIC) { 228 printf("bus is not magical"); 229 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 230 return ENOEXEC; 231 } 232 233 /* 234 * Prefault in pages to minimize runtime penalty with buslock. 235 * Use 512 instead of PAGE_SIZE to make sure we catch cases where 236 * rump kernel PAGE_SIZE > host page size. 237 */ 238 for (p = (uint8_t *)sc->sc_busmem; 239 p < (uint8_t *)sc->sc_busmem + BUSMEM_SIZE; 240 p += 512) 241 v = *p; 242 243 shmif_lockbus(sc->sc_busmem); 244 /* we're first? initialize bus */ 245 if (sc->sc_busmem->shm_magic == 0) { 246 sc->sc_busmem->shm_magic = SHMIF_MAGIC; 247 sc->sc_busmem->shm_first = BUSMEM_DATASIZE; 248 } 249 250 sc->sc_nextpacket = sc->sc_busmem->shm_last; 251 sc->sc_devgen = sc->sc_busmem->shm_gen; 252 253 #ifdef PREFAULT_RW 254 for (p = (uint8_t *)sc->sc_busmem; 255 p < (uint8_t *)sc->sc_busmem + BUSMEM_SIZE; 256 p += PAGE_SIZE) { 257 v = *p; 258 *p = v; 259 } 260 #endif 261 shmif_unlockbus(sc->sc_busmem); 262 263 sc->sc_kq = -1; 264 error = rumpcomp_shmif_watchsetup(&sc->sc_kq, memfd); 265 if (error) { 266 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 267 return error; 268 } 269 270 sc->sc_memfd = memfd; 271 272 return error; 273 } 274 275 static void 276 finibackend(struct shmif_sc *sc) 277 { 278 279 if (sc->sc_backfile == NULL) 280 return; 281 282 if (sc->sc_backfile) { 283 kmem_free(sc->sc_backfile, sc->sc_backfilelen); 284 sc->sc_backfile = NULL; 285 sc->sc_backfilelen = 0; 286 } 287 288 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 289 rumpuser_close(sc->sc_memfd); 290 rumpuser_close(sc->sc_kq); 291 292 sc->sc_memfd = -1; 293 } 294 295 int 296 rump_shmif_create(const char *path, int *ifnum) 297 { 298 struct shmif_sc *sc; 299 vmem_addr_t t; 300 int unit, error; 301 int memfd = -1; /* XXXgcc */ 302 303 if (path) { 304 error = rumpuser_open(path, 305 RUMPUSER_OPEN_RDWR | RUMPUSER_OPEN_CREATE, &memfd); 306 if (error) 307 return error; 308 } 309 310 error = vmem_xalloc(shmif_units, 1, 0, 0, 0, 311 VMEM_ADDR_MIN, VMEM_ADDR_MAX, VM_INSTANTFIT | VM_SLEEP, &t); 312 313 if (error != 0) { 314 if (path) 315 rumpuser_close(memfd); 316 return error; 317 } 318 319 unit = t - 1; 320 321 if ((error = allocif(unit, &sc)) != 0) { 322 if (path) 323 rumpuser_close(memfd); 324 return error; 325 } 326 327 if (!path) 328 goto out; 329 330 error = initbackend(sc, memfd); 331 if (error) { 332 shmif_unclone(&sc->sc_ec.ec_if); 333 return error; 334 } 335 336 sc->sc_backfilelen = strlen(path)+1; 337 sc->sc_backfile = kmem_alloc(sc->sc_backfilelen, KM_SLEEP); 338 strcpy(sc->sc_backfile, path); 339 340 out: 341 if (ifnum) 342 *ifnum = unit; 343 344 return 0; 345 } 346 347 static int 348 shmif_clone(struct if_clone *ifc, int unit) 349 { 350 int rc; 351 vmem_addr_t unit2; 352 353 /* 354 * Ok, we know the unit number, but we must still reserve it. 355 * Otherwise the wildcard-side of things might get the same one. 356 * This is slightly offset-happy due to vmem. First, we offset 357 * the range of unit numbers by +1 since vmem cannot deal with 358 * ranges starting from 0. Talk about uuuh. 359 */ 360 rc = vmem_xalloc(shmif_units, 1, 0, 0, 0, unit+1, unit+1, 361 VM_SLEEP | VM_INSTANTFIT, &unit2); 362 KASSERT(rc == 0 && unit2-1 == unit); 363 364 return allocif(unit, NULL); 365 } 366 367 static int 368 shmif_unclone(struct ifnet *ifp) 369 { 370 struct shmif_sc *sc = ifp->if_softc; 371 372 shmif_stop(ifp, 1); 373 if_down(ifp); 374 finibackend(sc); 375 376 mutex_enter(&sc->sc_mtx); 377 sc->sc_dying = true; 378 cv_broadcast(&sc->sc_cv); 379 mutex_exit(&sc->sc_mtx); 380 381 if (sc->sc_rcvl) 382 kthread_join(sc->sc_rcvl); 383 sc->sc_rcvl = NULL; 384 385 vmem_xfree(shmif_units, sc->sc_unit+1, 1); 386 387 ether_ifdetach(ifp); 388 if_detach(ifp); 389 390 cv_destroy(&sc->sc_cv); 391 mutex_destroy(&sc->sc_mtx); 392 393 kmem_free(sc, sizeof(*sc)); 394 395 return 0; 396 } 397 398 static int 399 shmif_init(struct ifnet *ifp) 400 { 401 struct shmif_sc *sc = ifp->if_softc; 402 int error = 0; 403 404 if (sc->sc_memfd == -1) 405 return ENXIO; 406 KASSERT(sc->sc_busmem); 407 408 ifp->if_flags |= IFF_RUNNING; 409 410 mutex_enter(&sc->sc_mtx); 411 sc->sc_nextpacket = sc->sc_busmem->shm_last; 412 sc->sc_devgen = sc->sc_busmem->shm_gen; 413 414 cv_broadcast(&sc->sc_cv); 415 mutex_exit(&sc->sc_mtx); 416 417 return error; 418 } 419 420 static int 421 shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data) 422 { 423 struct shmif_sc *sc = ifp->if_softc; 424 struct ifdrv *ifd; 425 char *path; 426 int s, rv, memfd; 427 428 s = splnet(); 429 switch (cmd) { 430 case SIOCGLINKSTR: 431 ifd = data; 432 433 if (sc->sc_backfilelen == 0) { 434 rv = ENOENT; 435 break; 436 } 437 438 ifd->ifd_len = sc->sc_backfilelen; 439 if (ifd->ifd_cmd == IFLINKSTR_QUERYLEN) { 440 rv = 0; 441 break; 442 } 443 444 if (ifd->ifd_cmd != 0) { 445 rv = EINVAL; 446 break; 447 } 448 449 rv = copyoutstr(sc->sc_backfile, ifd->ifd_data, 450 MIN(sc->sc_backfilelen, ifd->ifd_len), NULL); 451 break; 452 case SIOCSLINKSTR: 453 if (ifp->if_flags & IFF_UP) { 454 rv = EBUSY; 455 break; 456 } 457 458 ifd = data; 459 if (ifd->ifd_cmd == IFLINKSTR_UNSET) { 460 finibackend(sc); 461 rv = 0; 462 break; 463 } else if (ifd->ifd_cmd != 0) { 464 rv = EINVAL; 465 break; 466 } else if (sc->sc_backfile) { 467 rv = EBUSY; 468 break; 469 } 470 471 if (ifd->ifd_len > MAXPATHLEN) { 472 rv = E2BIG; 473 break; 474 } else if (ifd->ifd_len < 1) { 475 rv = EINVAL; 476 break; 477 } 478 479 path = kmem_alloc(ifd->ifd_len, KM_SLEEP); 480 rv = copyinstr(ifd->ifd_data, path, ifd->ifd_len, NULL); 481 if (rv) { 482 kmem_free(path, ifd->ifd_len); 483 break; 484 } 485 rv = rumpuser_open(path, 486 RUMPUSER_OPEN_RDWR | RUMPUSER_OPEN_CREATE, &memfd); 487 if (rv) { 488 kmem_free(path, ifd->ifd_len); 489 break; 490 } 491 rv = initbackend(sc, memfd); 492 if (rv) { 493 kmem_free(path, ifd->ifd_len); 494 rumpuser_close(memfd); 495 break; 496 } 497 sc->sc_backfile = path; 498 sc->sc_backfilelen = ifd->ifd_len; 499 500 break; 501 default: 502 rv = ether_ioctl(ifp, cmd, data); 503 if (rv == ENETRESET) 504 rv = 0; 505 break; 506 } 507 splx(s); 508 509 return rv; 510 } 511 512 /* send everything in-context since it's just a matter of mem-to-mem copy */ 513 static void 514 shmif_start(struct ifnet *ifp) 515 { 516 struct shmif_sc *sc = ifp->if_softc; 517 struct shmif_mem *busmem = sc->sc_busmem; 518 struct mbuf *m, *m0; 519 uint32_t dataoff; 520 uint32_t pktsize, pktwrote; 521 bool wrote = false; 522 bool wrap; 523 524 ifp->if_flags |= IFF_OACTIVE; 525 526 for (;;) { 527 struct shmif_pkthdr sp; 528 struct timeval tv; 529 530 IF_DEQUEUE(&ifp->if_snd, m0); 531 if (m0 == NULL) { 532 break; 533 } 534 535 pktsize = 0; 536 for (m = m0; m != NULL; m = m->m_next) { 537 pktsize += m->m_len; 538 } 539 KASSERT(pktsize <= ETHERMTU + ETHER_HDR_LEN); 540 541 getmicrouptime(&tv); 542 sp.sp_len = pktsize; 543 sp.sp_sec = tv.tv_sec; 544 sp.sp_usec = tv.tv_usec; 545 546 bpf_mtap(ifp, m0); 547 548 shmif_lockbus(busmem); 549 KASSERT(busmem->shm_magic == SHMIF_MAGIC); 550 busmem->shm_last = shmif_nextpktoff(busmem, busmem->shm_last); 551 552 wrap = false; 553 dataoff = shmif_buswrite(busmem, 554 busmem->shm_last, &sp, sizeof(sp), &wrap); 555 pktwrote = 0; 556 for (m = m0; m != NULL; m = m->m_next) { 557 pktwrote += m->m_len; 558 dataoff = shmif_buswrite(busmem, dataoff, 559 mtod(m, void *), m->m_len, &wrap); 560 } 561 KASSERT(pktwrote == pktsize); 562 if (wrap) { 563 busmem->shm_gen++; 564 DPRINTF(("bus generation now %" PRIu64 "\n", 565 busmem->shm_gen)); 566 } 567 shmif_unlockbus(busmem); 568 569 m_freem(m0); 570 wrote = true; 571 572 DPRINTF(("shmif_start: send %d bytes at off %d\n", 573 pktsize, busmem->shm_last)); 574 } 575 576 ifp->if_flags &= ~IFF_OACTIVE; 577 578 /* wakeup? */ 579 if (wrote) { 580 dowakeup(sc); 581 } 582 } 583 584 static void 585 shmif_stop(struct ifnet *ifp, int disable) 586 { 587 struct shmif_sc *sc = ifp->if_softc; 588 589 ifp->if_flags &= ~IFF_RUNNING; 590 membar_producer(); 591 592 /* 593 * wakeup thread. this will of course wake up all bus 594 * listeners, but that's life. 595 */ 596 if (sc->sc_memfd != -1) { 597 dowakeup(sc); 598 } 599 } 600 601 602 /* 603 * Check if we have been sleeping too long. Basically, 604 * our in-sc nextpkt must by first <= nextpkt <= last"+1". 605 * We use the fact that first is guaranteed to never overlap 606 * with the last frame in the ring. 607 */ 608 static __inline bool 609 stillvalid_p(struct shmif_sc *sc) 610 { 611 struct shmif_mem *busmem = sc->sc_busmem; 612 unsigned gendiff = busmem->shm_gen - sc->sc_devgen; 613 uint32_t lastoff, devoff; 614 615 KASSERT(busmem->shm_first != busmem->shm_last); 616 617 /* normalize onto a 2x busmem chunk */ 618 devoff = sc->sc_nextpacket; 619 lastoff = shmif_nextpktoff(busmem, busmem->shm_last); 620 621 /* trivial case */ 622 if (gendiff > 1) 623 return false; 624 KASSERT(gendiff <= 1); 625 626 /* Normalize onto 2x busmem chunk */ 627 if (busmem->shm_first >= lastoff) { 628 lastoff += BUSMEM_DATASIZE; 629 if (gendiff == 0) 630 devoff += BUSMEM_DATASIZE; 631 } else { 632 if (gendiff) 633 return false; 634 } 635 636 return devoff >= busmem->shm_first && devoff <= lastoff; 637 } 638 639 static void 640 shmif_rcv(void *arg) 641 { 642 struct ifnet *ifp = arg; 643 struct shmif_sc *sc = ifp->if_softc; 644 struct shmif_mem *busmem; 645 struct mbuf *m = NULL; 646 struct ether_header *eth; 647 uint32_t nextpkt; 648 bool wrap, passup; 649 int error; 650 const int align 651 = ALIGN(sizeof(struct ether_header)) - sizeof(struct ether_header); 652 653 reup: 654 mutex_enter(&sc->sc_mtx); 655 while ((ifp->if_flags & IFF_RUNNING) == 0 && !sc->sc_dying) 656 cv_wait(&sc->sc_cv, &sc->sc_mtx); 657 mutex_exit(&sc->sc_mtx); 658 659 busmem = sc->sc_busmem; 660 661 while (ifp->if_flags & IFF_RUNNING) { 662 struct shmif_pkthdr sp; 663 664 if (m == NULL) { 665 m = m_gethdr(M_WAIT, MT_DATA); 666 MCLGET(m, M_WAIT); 667 m->m_data += align; 668 } 669 670 DPRINTF(("waiting %d/%" PRIu64 "\n", 671 sc->sc_nextpacket, sc->sc_devgen)); 672 KASSERT(m->m_flags & M_EXT); 673 674 shmif_lockbus(busmem); 675 KASSERT(busmem->shm_magic == SHMIF_MAGIC); 676 KASSERT(busmem->shm_gen >= sc->sc_devgen); 677 678 /* need more data? */ 679 if (sc->sc_devgen == busmem->shm_gen && 680 shmif_nextpktoff(busmem, busmem->shm_last) 681 == sc->sc_nextpacket) { 682 shmif_unlockbus(busmem); 683 error = 0; 684 rumpcomp_shmif_watchwait(sc->sc_kq); 685 if (__predict_false(error)) 686 printf("shmif_rcv: wait failed %d\n", error); 687 membar_consumer(); 688 continue; 689 } 690 691 if (stillvalid_p(sc)) { 692 nextpkt = sc->sc_nextpacket; 693 } else { 694 KASSERT(busmem->shm_gen > 0); 695 nextpkt = busmem->shm_first; 696 if (busmem->shm_first > busmem->shm_last) 697 sc->sc_devgen = busmem->shm_gen - 1; 698 else 699 sc->sc_devgen = busmem->shm_gen; 700 DPRINTF(("dev %p overrun, new data: %d/%" PRIu64 "\n", 701 sc, nextpkt, sc->sc_devgen)); 702 } 703 704 /* 705 * If our read pointer is ahead the bus last write, our 706 * generation must be one behind. 707 */ 708 KASSERT(!(nextpkt > busmem->shm_last 709 && sc->sc_devgen == busmem->shm_gen)); 710 711 wrap = false; 712 nextpkt = shmif_busread(busmem, &sp, 713 nextpkt, sizeof(sp), &wrap); 714 KASSERT(sp.sp_len <= ETHERMTU + ETHER_HDR_LEN); 715 nextpkt = shmif_busread(busmem, mtod(m, void *), 716 nextpkt, sp.sp_len, &wrap); 717 718 DPRINTF(("shmif_rcv: read packet of length %d at %d\n", 719 sp.sp_len, nextpkt)); 720 721 sc->sc_nextpacket = nextpkt; 722 shmif_unlockbus(sc->sc_busmem); 723 724 if (wrap) { 725 sc->sc_devgen++; 726 DPRINTF(("dev %p generation now %" PRIu64 "\n", 727 sc, sc->sc_devgen)); 728 } 729 730 /* 731 * Ignore packets too short to possibly be valid. 732 * This is hit at least for the first frame on a new bus. 733 */ 734 if (__predict_false(sp.sp_len < ETHER_HDR_LEN)) { 735 DPRINTF(("shmif read packet len %d < ETHER_HDR_LEN\n", 736 sp.sp_len)); 737 continue; 738 } 739 740 m->m_len = m->m_pkthdr.len = sp.sp_len; 741 m->m_pkthdr.rcvif = ifp; 742 743 /* 744 * Test if we want to pass the packet upwards 745 */ 746 eth = mtod(m, struct ether_header *); 747 if (memcmp(eth->ether_dhost, CLLADDR(ifp->if_sadl), 748 ETHER_ADDR_LEN) == 0) { 749 passup = true; 750 } else if (ETHER_IS_MULTICAST(eth->ether_dhost)) { 751 passup = true; 752 } else if (ifp->if_flags & IFF_PROMISC) { 753 m->m_flags |= M_PROMISC; 754 passup = true; 755 } else { 756 passup = false; 757 } 758 759 if (passup) { 760 KERNEL_LOCK(1, NULL); 761 bpf_mtap(ifp, m); 762 ifp->if_input(ifp, m); 763 KERNEL_UNLOCK_ONE(NULL); 764 m = NULL; 765 } 766 /* else: reuse mbuf for a future packet */ 767 } 768 m_freem(m); 769 m = NULL; 770 771 if (!sc->sc_dying) 772 goto reup; 773 774 kthread_exit(0); 775 } 776
Indexes created Wed Sep 24 15:09:51 GMT 2025