if_shmem.c revision 1.63.2.4
1 /* $NetBSD: if_shmem.c,v 1.63.2.4 2017/02/05 13:41:01 skrll 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 1.63.2.4 2017/02/05 13:41:01 skrll 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-sys/kern.h> 51 #include <rump-sys/net.h> 52 53 #include <rump/rump.h> 54 #include <rump/rumpuser.h> 55 56 #include "shmif_user.h" 57 58 static int shmif_clone(struct if_clone *, int); 59 static int shmif_unclone(struct ifnet *); 60 61 struct if_clone shmif_cloner = 62 IF_CLONE_INITIALIZER("shmif", shmif_clone, shmif_unclone); 63 64 /* 65 * Do r/w prefault for backend pages when attaching the interface. 66 * At least logically thinking improves performance (although no 67 * mlocking is done, so they might go away). 68 */ 69 #define PREFAULT_RW 70 71 /* 72 * A virtual ethernet interface which uses shared memory from a 73 * memory mapped file as the bus. 74 */ 75 76 static int shmif_init(struct ifnet *); 77 static int shmif_ioctl(struct ifnet *, u_long, void *); 78 static void shmif_start(struct ifnet *); 79 static void shmif_stop(struct ifnet *, int); 80 81 #include "shmifvar.h" 82 83 struct shmif_sc { 84 struct ethercom sc_ec; 85 struct shmif_mem *sc_busmem; 86 int sc_memfd; 87 int sc_kq; 88 int sc_unit; 89 90 char *sc_backfile; 91 size_t sc_backfilelen; 92 93 uint64_t sc_devgen; 94 uint32_t sc_nextpacket; 95 96 kmutex_t sc_mtx; 97 kcondvar_t sc_cv; 98 99 struct lwp *sc_rcvl; 100 bool sc_dying; 101 102 uint64_t sc_uuid; 103 }; 104 105 static void shmif_rcv(void *); 106 107 #define LOCK_UNLOCKED 0 108 #define LOCK_LOCKED 1 109 #define LOCK_COOLDOWN 1001 110 111 vmem_t *shmif_units; 112 113 static void 114 dowakeup(struct shmif_sc *sc) 115 { 116 struct rumpuser_iovec iov; 117 uint32_t ver = SHMIF_VERSION; 118 size_t n; 119 120 iov.iov_base = &ver; 121 iov.iov_len = sizeof(ver); 122 rumpuser_iovwrite(sc->sc_memfd, &iov, 1, IFMEM_WAKEUP, &n); 123 } 124 125 /* 126 * This locking needs work and will misbehave severely if: 127 * 1) the backing memory has to be paged in 128 * 2) some lockholder exits while holding the lock 129 */ 130 static void 131 shmif_lockbus(struct shmif_mem *busmem) 132 { 133 int i = 0; 134 135 while (__predict_false(atomic_cas_32(&busmem->shm_lock, 136 LOCK_UNLOCKED, LOCK_LOCKED) == LOCK_LOCKED)) { 137 if (__predict_false(++i > LOCK_COOLDOWN)) { 138 /* wait 1ms */ 139 rumpuser_clock_sleep(RUMPUSER_CLOCK_RELWALL, 140 0, 1000*1000); 141 i = 0; 142 } 143 continue; 144 } 145 membar_enter(); 146 } 147 148 static void 149 shmif_unlockbus(struct shmif_mem *busmem) 150 { 151 unsigned int old __diagused; 152 153 membar_exit(); 154 old = atomic_swap_32(&busmem->shm_lock, LOCK_UNLOCKED); 155 KASSERT(old == LOCK_LOCKED); 156 } 157 158 static int 159 allocif(int unit, struct shmif_sc **scp) 160 { 161 uint8_t enaddr[ETHER_ADDR_LEN] = { 0xb2, 0xa0, 0x00, 0x00, 0x00, 0x00 }; 162 struct shmif_sc *sc; 163 struct ifnet *ifp; 164 uint32_t randnum; 165 int error; 166 167 randnum = cprng_fast32(); 168 memcpy(&enaddr[2], &randnum, sizeof(randnum)); 169 170 sc = kmem_zalloc(sizeof(*sc), KM_SLEEP); 171 sc->sc_memfd = -1; 172 sc->sc_unit = unit; 173 sc->sc_uuid = cprng_fast64(); 174 175 ifp = &sc->sc_ec.ec_if; 176 177 snprintf(ifp->if_xname, sizeof(ifp->if_xname), "shmif%d", unit); 178 ifp->if_softc = sc; 179 ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_MULTICAST; 180 ifp->if_init = shmif_init; 181 ifp->if_ioctl = shmif_ioctl; 182 ifp->if_start = shmif_start; 183 ifp->if_stop = shmif_stop; 184 ifp->if_mtu = ETHERMTU; 185 ifp->if_dlt = DLT_EN10MB; 186 187 mutex_init(&sc->sc_mtx, MUTEX_DEFAULT, IPL_NONE); 188 cv_init(&sc->sc_cv, "shmifcv"); 189 190 if_initialize(ifp); 191 ether_ifattach(ifp, enaddr); 192 if_register(ifp); 193 194 aprint_verbose("shmif%d: Ethernet address %s\n", 195 unit, ether_sprintf(enaddr)); 196 197 if (scp) 198 *scp = sc; 199 200 error = 0; 201 if (rump_threads) { 202 error = kthread_create(PRI_NONE, 203 KTHREAD_MPSAFE | KTHREAD_MUSTJOIN, NULL, 204 shmif_rcv, ifp, &sc->sc_rcvl, "shmif"); 205 } else { 206 printf("WARNING: threads not enabled, shmif NOT working\n"); 207 } 208 209 if (error) { 210 shmif_unclone(ifp); 211 } 212 213 return error; 214 } 215 216 static int 217 initbackend(struct shmif_sc *sc, int memfd) 218 { 219 volatile uint8_t v; 220 volatile uint8_t *p; 221 void *mem; 222 int error; 223 224 error = rumpcomp_shmif_mmap(memfd, BUSMEM_SIZE, &mem); 225 if (error) 226 return error; 227 sc->sc_busmem = mem; 228 229 if (sc->sc_busmem->shm_magic 230 && sc->sc_busmem->shm_magic != SHMIF_MAGIC) { 231 printf("bus is not magical"); 232 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 233 return ENOEXEC; 234 } 235 236 /* 237 * Prefault in pages to minimize runtime penalty with buslock. 238 * Use 512 instead of PAGE_SIZE to make sure we catch cases where 239 * rump kernel PAGE_SIZE > host page size. 240 */ 241 for (p = (uint8_t *)sc->sc_busmem; 242 p < (uint8_t *)sc->sc_busmem + BUSMEM_SIZE; 243 p += 512) 244 v = *p; 245 246 shmif_lockbus(sc->sc_busmem); 247 /* we're first? initialize bus */ 248 if (sc->sc_busmem->shm_magic == 0) { 249 sc->sc_busmem->shm_magic = SHMIF_MAGIC; 250 sc->sc_busmem->shm_first = BUSMEM_DATASIZE; 251 } 252 253 sc->sc_nextpacket = sc->sc_busmem->shm_last; 254 sc->sc_devgen = sc->sc_busmem->shm_gen; 255 256 #ifdef PREFAULT_RW 257 for (p = (uint8_t *)sc->sc_busmem; 258 p < (uint8_t *)sc->sc_busmem + BUSMEM_SIZE; 259 p += PAGE_SIZE) { 260 v = *p; 261 *p = v; 262 } 263 #endif 264 shmif_unlockbus(sc->sc_busmem); 265 266 sc->sc_kq = -1; 267 error = rumpcomp_shmif_watchsetup(&sc->sc_kq, memfd); 268 if (error) { 269 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 270 return error; 271 } 272 273 sc->sc_memfd = memfd; 274 275 return error; 276 } 277 278 static void 279 finibackend(struct shmif_sc *sc) 280 { 281 282 if (sc->sc_backfile == NULL) 283 return; 284 285 if (sc->sc_backfile) { 286 kmem_free(sc->sc_backfile, sc->sc_backfilelen); 287 sc->sc_backfile = NULL; 288 sc->sc_backfilelen = 0; 289 } 290 291 rumpuser_unmap(sc->sc_busmem, BUSMEM_SIZE); 292 rumpuser_close(sc->sc_memfd); 293 rumpuser_close(sc->sc_kq); 294 295 sc->sc_memfd = -1; 296 } 297 298 int 299 rump_shmif_create(const char *path, int *ifnum) 300 { 301 struct shmif_sc *sc; 302 vmem_addr_t t; 303 int unit, error; 304 int memfd = -1; /* XXXgcc */ 305 306 if (path) { 307 error = rumpuser_open(path, 308 RUMPUSER_OPEN_RDWR | RUMPUSER_OPEN_CREATE, &memfd); 309 if (error) 310 return error; 311 } 312 313 error = vmem_xalloc(shmif_units, 1, 0, 0, 0, 314 VMEM_ADDR_MIN, VMEM_ADDR_MAX, VM_INSTANTFIT | VM_SLEEP, &t); 315 316 if (error != 0) { 317 if (path) 318 rumpuser_close(memfd); 319 return error; 320 } 321 322 unit = t - 1; 323 324 if ((error = allocif(unit, &sc)) != 0) { 325 if (path) 326 rumpuser_close(memfd); 327 return error; 328 } 329 330 if (!path) 331 goto out; 332 333 error = initbackend(sc, memfd); 334 if (error) { 335 shmif_unclone(&sc->sc_ec.ec_if); 336 return error; 337 } 338 339 sc->sc_backfilelen = strlen(path)+1; 340 sc->sc_backfile = kmem_alloc(sc->sc_backfilelen, KM_SLEEP); 341 strcpy(sc->sc_backfile, path); 342 343 out: 344 if (ifnum) 345 *ifnum = unit; 346 347 return 0; 348 } 349 350 static int 351 shmif_clone(struct if_clone *ifc, int unit) 352 { 353 int rc __diagused; 354 vmem_addr_t unit2; 355 356 /* 357 * Ok, we know the unit number, but we must still reserve it. 358 * Otherwise the wildcard-side of things might get the same one. 359 * This is slightly offset-happy due to vmem. First, we offset 360 * the range of unit numbers by +1 since vmem cannot deal with 361 * ranges starting from 0. Talk about uuuh. 362 */ 363 rc = vmem_xalloc(shmif_units, 1, 0, 0, 0, unit+1, unit+1, 364 VM_SLEEP | VM_INSTANTFIT, &unit2); 365 KASSERT(rc == 0 && unit2-1 == unit); 366 367 return allocif(unit, NULL); 368 } 369 370 static int 371 shmif_unclone(struct ifnet *ifp) 372 { 373 struct shmif_sc *sc = ifp->if_softc; 374 375 shmif_stop(ifp, 1); 376 if_down(ifp); 377 378 mutex_enter(&sc->sc_mtx); 379 sc->sc_dying = true; 380 cv_broadcast(&sc->sc_cv); 381 mutex_exit(&sc->sc_mtx); 382 383 if (sc->sc_rcvl) 384 kthread_join(sc->sc_rcvl); 385 sc->sc_rcvl = NULL; 386 387 /* 388 * Need to be called after the kthread left, otherwise closing kqueue 389 * (sc_kq) hangs sometimes perhaps because of a race condition between 390 * close and kevent in the kthread on the kqueue. 391 */ 392 finibackend(sc); 393 394 vmem_xfree(shmif_units, sc->sc_unit+1, 1); 395 396 ether_ifdetach(ifp); 397 if_detach(ifp); 398 399 cv_destroy(&sc->sc_cv); 400 mutex_destroy(&sc->sc_mtx); 401 402 kmem_free(sc, sizeof(*sc)); 403 404 return 0; 405 } 406 407 static int 408 shmif_init(struct ifnet *ifp) 409 { 410 struct shmif_sc *sc = ifp->if_softc; 411 int error = 0; 412 413 if (sc->sc_memfd == -1) 414 return ENXIO; 415 KASSERT(sc->sc_busmem); 416 417 ifp->if_flags |= IFF_RUNNING; 418 419 mutex_enter(&sc->sc_mtx); 420 sc->sc_nextpacket = sc->sc_busmem->shm_last; 421 sc->sc_devgen = sc->sc_busmem->shm_gen; 422 423 cv_broadcast(&sc->sc_cv); 424 mutex_exit(&sc->sc_mtx); 425 426 return error; 427 } 428 429 static int 430 shmif_ioctl(struct ifnet *ifp, u_long cmd, void *data) 431 { 432 struct shmif_sc *sc = ifp->if_softc; 433 struct ifdrv *ifd; 434 char *path; 435 int s, rv, memfd; 436 437 s = splnet(); 438 switch (cmd) { 439 case SIOCGLINKSTR: 440 ifd = data; 441 442 if (sc->sc_backfilelen == 0) { 443 rv = ENOENT; 444 break; 445 } 446 447 ifd->ifd_len = sc->sc_backfilelen; 448 if (ifd->ifd_cmd == IFLINKSTR_QUERYLEN) { 449 rv = 0; 450 break; 451 } 452 453 if (ifd->ifd_cmd != 0) { 454 rv = EINVAL; 455 break; 456 } 457 458 rv = copyoutstr(sc->sc_backfile, ifd->ifd_data, 459 MIN(sc->sc_backfilelen, ifd->ifd_len), NULL); 460 break; 461 case SIOCSLINKSTR: 462 if (ifp->if_flags & IFF_UP) { 463 rv = EBUSY; 464 break; 465 } 466 467 ifd = data; 468 if (ifd->ifd_cmd == IFLINKSTR_UNSET) { 469 finibackend(sc); 470 rv = 0; 471 break; 472 } else if (ifd->ifd_cmd != 0) { 473 rv = EINVAL; 474 break; 475 } else if (sc->sc_backfile) { 476 rv = EBUSY; 477 break; 478 } 479 480 if (ifd->ifd_len > MAXPATHLEN) { 481 rv = E2BIG; 482 break; 483 } else if (ifd->ifd_len < 1) { 484 rv = EINVAL; 485 break; 486 } 487 488 path = kmem_alloc(ifd->ifd_len, KM_SLEEP); 489 rv = copyinstr(ifd->ifd_data, path, ifd->ifd_len, NULL); 490 if (rv) { 491 kmem_free(path, ifd->ifd_len); 492 break; 493 } 494 rv = rumpuser_open(path, 495 RUMPUSER_OPEN_RDWR | RUMPUSER_OPEN_CREATE, &memfd); 496 if (rv) { 497 kmem_free(path, ifd->ifd_len); 498 break; 499 } 500 rv = initbackend(sc, memfd); 501 if (rv) { 502 kmem_free(path, ifd->ifd_len); 503 rumpuser_close(memfd); 504 break; 505 } 506 sc->sc_backfile = path; 507 sc->sc_backfilelen = ifd->ifd_len; 508 509 break; 510 default: 511 rv = ether_ioctl(ifp, cmd, data); 512 if (rv == ENETRESET) 513 rv = 0; 514 break; 515 } 516 splx(s); 517 518 return rv; 519 } 520 521 /* send everything in-context since it's just a matter of mem-to-mem copy */ 522 static void 523 shmif_start(struct ifnet *ifp) 524 { 525 struct shmif_sc *sc = ifp->if_softc; 526 struct shmif_mem *busmem = sc->sc_busmem; 527 struct mbuf *m, *m0; 528 uint32_t dataoff; 529 uint32_t pktsize, pktwrote; 530 bool wrote = false; 531 bool wrap; 532 533 ifp->if_flags |= IFF_OACTIVE; 534 535 for (;;) { 536 struct shmif_pkthdr sp; 537 struct timeval tv; 538 539 IF_DEQUEUE(&ifp->if_snd, m0); 540 if (m0 == NULL) { 541 break; 542 } 543 544 pktsize = 0; 545 for (m = m0; m != NULL; m = m->m_next) { 546 pktsize += m->m_len; 547 } 548 KASSERT(pktsize <= ETHERMTU + ETHER_HDR_LEN); 549 550 getmicrouptime(&tv); 551 sp.sp_len = pktsize; 552 sp.sp_sec = tv.tv_sec; 553 sp.sp_usec = tv.tv_usec; 554 sp.sp_sender = sc->sc_uuid; 555 556 bpf_mtap(ifp, m0); 557 558 shmif_lockbus(busmem); 559 KASSERT(busmem->shm_magic == SHMIF_MAGIC); 560 busmem->shm_last = shmif_nextpktoff(busmem, busmem->shm_last); 561 562 wrap = false; 563 dataoff = shmif_buswrite(busmem, 564 busmem->shm_last, &sp, sizeof(sp), &wrap); 565 pktwrote = 0; 566 for (m = m0; m != NULL; m = m->m_next) { 567 pktwrote += m->m_len; 568 dataoff = shmif_buswrite(busmem, dataoff, 569 mtod(m, void *), m->m_len, &wrap); 570 } 571 KASSERT(pktwrote == pktsize); 572 if (wrap) { 573 busmem->shm_gen++; 574 DPRINTF(("bus generation now %" PRIu64 "\n", 575 busmem->shm_gen)); 576 } 577 shmif_unlockbus(busmem); 578 579 m_freem(m0); 580 wrote = true; 581 ifp->if_opackets++; 582 583 DPRINTF(("shmif_start: send %d bytes at off %d\n", 584 pktsize, busmem->shm_last)); 585 } 586 587 ifp->if_flags &= ~IFF_OACTIVE; 588 589 /* wakeup? */ 590 if (wrote) { 591 dowakeup(sc); 592 } 593 } 594 595 static void 596 shmif_stop(struct ifnet *ifp, int disable) 597 { 598 struct shmif_sc *sc = ifp->if_softc; 599 600 ifp->if_flags &= ~IFF_RUNNING; 601 membar_producer(); 602 603 /* 604 * wakeup thread. this will of course wake up all bus 605 * listeners, but that's life. 606 */ 607 if (sc->sc_memfd != -1) { 608 dowakeup(sc); 609 } 610 } 611 612 613 /* 614 * Check if we have been sleeping too long. Basically, 615 * our in-sc nextpkt must by first <= nextpkt <= last"+1". 616 * We use the fact that first is guaranteed to never overlap 617 * with the last frame in the ring. 618 */ 619 static __inline bool 620 stillvalid_p(struct shmif_sc *sc) 621 { 622 struct shmif_mem *busmem = sc->sc_busmem; 623 unsigned gendiff = busmem->shm_gen - sc->sc_devgen; 624 uint32_t lastoff, devoff; 625 626 KASSERT(busmem->shm_first != busmem->shm_last); 627 628 /* normalize onto a 2x busmem chunk */ 629 devoff = sc->sc_nextpacket; 630 lastoff = shmif_nextpktoff(busmem, busmem->shm_last); 631 632 /* trivial case */ 633 if (gendiff > 1) 634 return false; 635 KASSERT(gendiff <= 1); 636 637 /* Normalize onto 2x busmem chunk */ 638 if (busmem->shm_first >= lastoff) { 639 lastoff += BUSMEM_DATASIZE; 640 if (gendiff == 0) 641 devoff += BUSMEM_DATASIZE; 642 } else { 643 if (gendiff) 644 return false; 645 } 646 647 return devoff >= busmem->shm_first && devoff <= lastoff; 648 } 649 650 static void 651 shmif_rcv(void *arg) 652 { 653 struct ifnet *ifp = arg; 654 struct shmif_sc *sc = ifp->if_softc; 655 struct shmif_mem *busmem; 656 struct mbuf *m = NULL; 657 struct ether_header *eth; 658 uint32_t nextpkt; 659 bool wrap, passup; 660 int error; 661 const int align 662 = ALIGN(sizeof(struct ether_header)) - sizeof(struct ether_header); 663 664 reup: 665 mutex_enter(&sc->sc_mtx); 666 while ((ifp->if_flags & IFF_RUNNING) == 0 && !sc->sc_dying) 667 cv_wait(&sc->sc_cv, &sc->sc_mtx); 668 mutex_exit(&sc->sc_mtx); 669 670 busmem = sc->sc_busmem; 671 672 while (ifp->if_flags & IFF_RUNNING) { 673 struct shmif_pkthdr sp; 674 675 if (m == NULL) { 676 m = m_gethdr(M_WAIT, MT_DATA); 677 MCLGET(m, M_WAIT); 678 m->m_data += align; 679 } 680 681 DPRINTF(("waiting %d/%" PRIu64 "\n", 682 sc->sc_nextpacket, sc->sc_devgen)); 683 KASSERT(m->m_flags & M_EXT); 684 685 shmif_lockbus(busmem); 686 KASSERT(busmem->shm_magic == SHMIF_MAGIC); 687 KASSERT(busmem->shm_gen >= sc->sc_devgen); 688 689 /* need more data? */ 690 if (sc->sc_devgen == busmem->shm_gen && 691 shmif_nextpktoff(busmem, busmem->shm_last) 692 == sc->sc_nextpacket) { 693 shmif_unlockbus(busmem); 694 error = rumpcomp_shmif_watchwait(sc->sc_kq); 695 if (__predict_false(error)) 696 printf("shmif_rcv: wait failed %d\n", error); 697 membar_consumer(); 698 continue; 699 } 700 701 if (stillvalid_p(sc)) { 702 nextpkt = sc->sc_nextpacket; 703 } else { 704 KASSERT(busmem->shm_gen > 0); 705 nextpkt = busmem->shm_first; 706 if (busmem->shm_first > busmem->shm_last) 707 sc->sc_devgen = busmem->shm_gen - 1; 708 else 709 sc->sc_devgen = busmem->shm_gen; 710 DPRINTF(("dev %p overrun, new data: %d/%" PRIu64 "\n", 711 sc, nextpkt, sc->sc_devgen)); 712 } 713 714 /* 715 * If our read pointer is ahead the bus last write, our 716 * generation must be one behind. 717 */ 718 KASSERT(!(nextpkt > busmem->shm_last 719 && sc->sc_devgen == busmem->shm_gen)); 720 721 wrap = false; 722 nextpkt = shmif_busread(busmem, &sp, 723 nextpkt, sizeof(sp), &wrap); 724 KASSERT(sp.sp_len <= ETHERMTU + ETHER_HDR_LEN); 725 nextpkt = shmif_busread(busmem, mtod(m, void *), 726 nextpkt, sp.sp_len, &wrap); 727 728 DPRINTF(("shmif_rcv: read packet of length %d at %d\n", 729 sp.sp_len, nextpkt)); 730 731 sc->sc_nextpacket = nextpkt; 732 shmif_unlockbus(sc->sc_busmem); 733 734 if (wrap) { 735 sc->sc_devgen++; 736 DPRINTF(("dev %p generation now %" PRIu64 "\n", 737 sc, sc->sc_devgen)); 738 } 739 740 /* 741 * Ignore packets too short to possibly be valid. 742 * This is hit at least for the first frame on a new bus. 743 */ 744 if (__predict_false(sp.sp_len < ETHER_HDR_LEN)) { 745 DPRINTF(("shmif read packet len %d < ETHER_HDR_LEN\n", 746 sp.sp_len)); 747 continue; 748 } 749 750 m->m_len = m->m_pkthdr.len = sp.sp_len; 751 m_set_rcvif(m, ifp); 752 753 /* 754 * Test if we want to pass the packet upwards 755 */ 756 eth = mtod(m, struct ether_header *); 757 if (sp.sp_sender == sc->sc_uuid) { 758 passup = false; 759 } else if (memcmp(eth->ether_dhost, CLLADDR(ifp->if_sadl), 760 ETHER_ADDR_LEN) == 0) { 761 passup = true; 762 } else if (ETHER_IS_MULTICAST(eth->ether_dhost)) { 763 passup = true; 764 } else if (ifp->if_flags & IFF_PROMISC) { 765 m->m_flags |= M_PROMISC; 766 passup = true; 767 } else { 768 passup = false; 769 } 770 771 if (passup) { 772 int bound; 773 KERNEL_LOCK(1, NULL); 774 /* Prevent LWP migrations between CPUs for psref(9) */ 775 bound = curlwp_bind(); 776 if_input(ifp, m); 777 curlwp_bindx(bound); 778 KERNEL_UNLOCK_ONE(NULL); 779 m = NULL; 780 } 781 /* else: reuse mbuf for a future packet */ 782 } 783 m_freem(m); 784 m = NULL; 785 786 if (!sc->sc_dying) 787 goto reup; 788 789 kthread_exit(0); 790 } 791
Indexes created Fri Sep 26 08:10:20 GMT 2025