1 /* $NetBSD: bpf.c,v 1.192 2015/10/14 19:40:09 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from the Stanford/CMU enet packet filter, 8 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 9 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 10 * Berkeley Laboratory. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)bpf.c 8.4 (Berkeley) 1/9/95 37 * static char rcsid[] = 38 * "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp "; 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.192 2015/10/14 19:40:09 christos Exp $"); 43 44 #if defined(_KERNEL_OPT) 45 #include "opt_bpf.h" 46 #include "sl.h" 47 #include "strip.h" 48 #endif 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/buf.h> 54 #include <sys/time.h> 55 #include <sys/proc.h> 56 #include <sys/ioctl.h> 57 #include <sys/conf.h> 58 #include <sys/vnode.h> 59 #include <sys/queue.h> 60 #include <sys/stat.h> 61 #include <sys/module.h> 62 #include <sys/once.h> 63 #include <sys/atomic.h> 64 65 #include <sys/file.h> 66 #include <sys/filedesc.h> 67 #include <sys/tty.h> 68 #include <sys/uio.h> 69 70 #include <sys/protosw.h> 71 #include <sys/socket.h> 72 #include <sys/errno.h> 73 #include <sys/kernel.h> 74 #include <sys/poll.h> 75 #include <sys/sysctl.h> 76 #include <sys/kauth.h> 77 78 #include <net/if.h> 79 #include <net/slip.h> 80 81 #include <net/bpf.h> 82 #include <net/bpfdesc.h> 83 #include <net/bpfjit.h> 84 85 #include <net/if_arc.h> 86 #include <net/if_ether.h> 87 88 #include <netinet/in.h> 89 #include <netinet/if_inarp.h> 90 91 92 #include <compat/sys/sockio.h> 93 94 #ifndef BPF_BUFSIZE 95 /* 96 * 4096 is too small for FDDI frames. 8192 is too small for gigabit Ethernet 97 * jumbos (circa 9k), ATM, or Intel gig/10gig ethernet jumbos (16k). 98 */ 99 # define BPF_BUFSIZE 32768 100 #endif 101 102 #define PRINET 26 /* interruptible */ 103 104 /* 105 * The default read buffer size, and limit for BIOCSBLEN, is sysctl'able. 106 * XXX the default values should be computed dynamically based 107 * on available memory size and available mbuf clusters. 108 */ 109 int bpf_bufsize = BPF_BUFSIZE; 110 int bpf_maxbufsize = BPF_DFLTBUFSIZE; /* XXX set dynamically, see above */ 111 bool bpf_jit = false; 112 113 struct bpfjit_ops bpfjit_module_ops = { 114 .bj_generate_code = NULL, 115 .bj_free_code = NULL 116 }; 117 118 /* 119 * Global BPF statistics returned by net.bpf.stats sysctl. 120 */ 121 struct bpf_stat bpf_gstats; 122 123 /* 124 * Use a mutex to avoid a race condition between gathering the stats/peers 125 * and opening/closing the device. 126 */ 127 static kmutex_t bpf_mtx; 128 129 /* 130 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 131 * bpf_dtab holds the descriptors, indexed by minor device # 132 */ 133 struct bpf_if *bpf_iflist; 134 LIST_HEAD(, bpf_d) bpf_list; 135 136 static int bpf_allocbufs(struct bpf_d *); 137 static void bpf_deliver(struct bpf_if *, 138 void *(*cpfn)(void *, const void *, size_t), 139 void *, u_int, u_int, const bool); 140 static void bpf_freed(struct bpf_d *); 141 static void bpf_ifname(struct ifnet *, struct ifreq *); 142 static void *bpf_mcpy(void *, const void *, size_t); 143 static int bpf_movein(struct uio *, int, uint64_t, 144 struct mbuf **, struct sockaddr *); 145 static void bpf_attachd(struct bpf_d *, struct bpf_if *); 146 static void bpf_detachd(struct bpf_d *); 147 static int bpf_setif(struct bpf_d *, struct ifreq *); 148 static void bpf_timed_out(void *); 149 static inline void 150 bpf_wakeup(struct bpf_d *); 151 static int bpf_hdrlen(struct bpf_d *); 152 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int, 153 void *(*)(void *, const void *, size_t), struct timespec *); 154 static void reset_d(struct bpf_d *); 155 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 156 static int bpf_setdlt(struct bpf_d *, u_int); 157 158 static int bpf_read(struct file *, off_t *, struct uio *, kauth_cred_t, 159 int); 160 static int bpf_write(struct file *, off_t *, struct uio *, kauth_cred_t, 161 int); 162 static int bpf_ioctl(struct file *, u_long, void *); 163 static int bpf_poll(struct file *, int); 164 static int bpf_stat(struct file *, struct stat *); 165 static int bpf_close(struct file *); 166 static int bpf_kqfilter(struct file *, struct knote *); 167 static void bpf_softintr(void *); 168 169 static const struct fileops bpf_fileops = { 170 .fo_read = bpf_read, 171 .fo_write = bpf_write, 172 .fo_ioctl = bpf_ioctl, 173 .fo_fcntl = fnullop_fcntl, 174 .fo_poll = bpf_poll, 175 .fo_stat = bpf_stat, 176 .fo_close = bpf_close, 177 .fo_kqfilter = bpf_kqfilter, 178 .fo_restart = fnullop_restart, 179 }; 180 181 dev_type_open(bpfopen); 182 183 const struct cdevsw bpf_cdevsw = { 184 .d_open = bpfopen, 185 .d_close = noclose, 186 .d_read = noread, 187 .d_write = nowrite, 188 .d_ioctl = noioctl, 189 .d_stop = nostop, 190 .d_tty = notty, 191 .d_poll = nopoll, 192 .d_mmap = nommap, 193 .d_kqfilter = nokqfilter, 194 .d_discard = nodiscard, 195 .d_flag = D_OTHER 196 }; 197 198 bpfjit_func_t 199 bpf_jit_generate(bpf_ctx_t *bc, void *code, size_t size) 200 { 201 202 membar_consumer(); 203 if (bpfjit_module_ops.bj_generate_code != NULL) { 204 return bpfjit_module_ops.bj_generate_code(bc, code, size); 205 } 206 return NULL; 207 } 208 209 void 210 bpf_jit_freecode(bpfjit_func_t jcode) 211 { 212 KASSERT(bpfjit_module_ops.bj_free_code != NULL); 213 bpfjit_module_ops.bj_free_code(jcode); 214 } 215 216 static int 217 bpf_movein(struct uio *uio, int linktype, uint64_t mtu, struct mbuf **mp, 218 struct sockaddr *sockp) 219 { 220 struct mbuf *m; 221 int error; 222 size_t len; 223 size_t hlen; 224 size_t align; 225 226 /* 227 * Build a sockaddr based on the data link layer type. 228 * We do this at this level because the ethernet header 229 * is copied directly into the data field of the sockaddr. 230 * In the case of SLIP, there is no header and the packet 231 * is forwarded as is. 232 * Also, we are careful to leave room at the front of the mbuf 233 * for the link level header. 234 */ 235 switch (linktype) { 236 237 case DLT_SLIP: 238 sockp->sa_family = AF_INET; 239 hlen = 0; 240 align = 0; 241 break; 242 243 case DLT_PPP: 244 sockp->sa_family = AF_UNSPEC; 245 hlen = 0; 246 align = 0; 247 break; 248 249 case DLT_EN10MB: 250 sockp->sa_family = AF_UNSPEC; 251 /* XXX Would MAXLINKHDR be better? */ 252 /* 6(dst)+6(src)+2(type) */ 253 hlen = sizeof(struct ether_header); 254 align = 2; 255 break; 256 257 case DLT_ARCNET: 258 sockp->sa_family = AF_UNSPEC; 259 hlen = ARC_HDRLEN; 260 align = 5; 261 break; 262 263 case DLT_FDDI: 264 sockp->sa_family = AF_LINK; 265 /* XXX 4(FORMAC)+6(dst)+6(src) */ 266 hlen = 16; 267 align = 0; 268 break; 269 270 case DLT_ECONET: 271 sockp->sa_family = AF_UNSPEC; 272 hlen = 6; 273 align = 2; 274 break; 275 276 case DLT_NULL: 277 sockp->sa_family = AF_UNSPEC; 278 hlen = 0; 279 align = 0; 280 break; 281 282 default: 283 return (EIO); 284 } 285 286 len = uio->uio_resid; 287 /* 288 * If there aren't enough bytes for a link level header or the 289 * packet length exceeds the interface mtu, return an error. 290 */ 291 if (len - hlen > mtu) 292 return (EMSGSIZE); 293 294 /* 295 * XXX Avoid complicated buffer chaining --- 296 * bail if it won't fit in a single mbuf. 297 * (Take into account possible alignment bytes) 298 */ 299 if (len + align > MCLBYTES) 300 return (EIO); 301 302 m = m_gethdr(M_WAIT, MT_DATA); 303 m->m_pkthdr.rcvif = NULL; 304 m->m_pkthdr.len = (int)(len - hlen); 305 if (len + align > MHLEN) { 306 m_clget(m, M_WAIT); 307 if ((m->m_flags & M_EXT) == 0) { 308 error = ENOBUFS; 309 goto bad; 310 } 311 } 312 313 /* Insure the data is properly aligned */ 314 if (align > 0) { 315 m->m_data += align; 316 m->m_len -= (int)align; 317 } 318 319 error = uiomove(mtod(m, void *), len, uio); 320 if (error) 321 goto bad; 322 if (hlen != 0) { 323 memcpy(sockp->sa_data, mtod(m, void *), hlen); 324 m->m_data += hlen; /* XXX */ 325 len -= hlen; 326 } 327 m->m_len = (int)len; 328 *mp = m; 329 return (0); 330 331 bad: 332 m_freem(m); 333 return (error); 334 } 335 336 /* 337 * Attach file to the bpf interface, i.e. make d listen on bp. 338 * Must be called at splnet. 339 */ 340 static void 341 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 342 { 343 KASSERT(mutex_owned(&bpf_mtx)); 344 /* 345 * Point d at bp, and add d to the interface's list of listeners. 346 * Finally, point the driver's bpf cookie at the interface so 347 * it will divert packets to bpf. 348 */ 349 d->bd_bif = bp; 350 d->bd_next = bp->bif_dlist; 351 bp->bif_dlist = d; 352 353 *bp->bif_driverp = bp; 354 } 355 356 /* 357 * Detach a file from its interface. 358 */ 359 static void 360 bpf_detachd(struct bpf_d *d) 361 { 362 struct bpf_d **p; 363 struct bpf_if *bp; 364 365 KASSERT(mutex_owned(&bpf_mtx)); 366 367 bp = d->bd_bif; 368 /* 369 * Check if this descriptor had requested promiscuous mode. 370 * If so, turn it off. 371 */ 372 if (d->bd_promisc) { 373 int error __diagused; 374 375 d->bd_promisc = 0; 376 /* 377 * Take device out of promiscuous mode. Since we were 378 * able to enter promiscuous mode, we should be able 379 * to turn it off. But we can get an error if 380 * the interface was configured down, so only panic 381 * if we don't get an unexpected error. 382 */ 383 error = ifpromisc(bp->bif_ifp, 0); 384 #ifdef DIAGNOSTIC 385 if (error) 386 printf("%s: ifpromisc failed: %d", __func__, error); 387 #endif 388 } 389 /* Remove d from the interface's descriptor list. */ 390 p = &bp->bif_dlist; 391 while (*p != d) { 392 p = &(*p)->bd_next; 393 if (*p == NULL) 394 panic("%s: descriptor not in list", __func__); 395 } 396 *p = (*p)->bd_next; 397 if (bp->bif_dlist == NULL) 398 /* 399 * Let the driver know that there are no more listeners. 400 */ 401 *d->bd_bif->bif_driverp = NULL; 402 d->bd_bif = NULL; 403 } 404 405 static int 406 doinit(void) 407 { 408 409 mutex_init(&bpf_mtx, MUTEX_DEFAULT, IPL_NONE); 410 411 LIST_INIT(&bpf_list); 412 413 bpf_gstats.bs_recv = 0; 414 bpf_gstats.bs_drop = 0; 415 bpf_gstats.bs_capt = 0; 416 417 return 0; 418 } 419 420 /* 421 * bpfilterattach() is called at boot time. 422 */ 423 /* ARGSUSED */ 424 void 425 bpfilterattach(int n) 426 { 427 static ONCE_DECL(control); 428 429 RUN_ONCE(&control, doinit); 430 } 431 432 /* 433 * Open ethernet device. Clones. 434 */ 435 /* ARGSUSED */ 436 int 437 bpfopen(dev_t dev, int flag, int mode, struct lwp *l) 438 { 439 struct bpf_d *d; 440 struct file *fp; 441 int error, fd; 442 443 /* falloc() will fill in the descriptor for us. */ 444 if ((error = fd_allocfile(&fp, &fd)) != 0) 445 return error; 446 447 d = malloc(sizeof(*d), M_DEVBUF, M_WAITOK|M_ZERO); 448 d->bd_bufsize = bpf_bufsize; 449 d->bd_seesent = 1; 450 d->bd_feedback = 0; 451 d->bd_pid = l->l_proc->p_pid; 452 #ifdef _LP64 453 if (curproc->p_flag & PK_32) 454 d->bd_compat32 = 1; 455 #endif 456 getnanotime(&d->bd_btime); 457 d->bd_atime = d->bd_mtime = d->bd_btime; 458 callout_init(&d->bd_callout, 0); 459 selinit(&d->bd_sel); 460 d->bd_sih = softint_establish(SOFTINT_CLOCK, bpf_softintr, d); 461 d->bd_jitcode = NULL; 462 463 mutex_enter(&bpf_mtx); 464 LIST_INSERT_HEAD(&bpf_list, d, bd_list); 465 mutex_exit(&bpf_mtx); 466 467 return fd_clone(fp, fd, flag, &bpf_fileops, d); 468 } 469 470 /* 471 * Close the descriptor by detaching it from its interface, 472 * deallocating its buffers, and marking it free. 473 */ 474 /* ARGSUSED */ 475 static int 476 bpf_close(struct file *fp) 477 { 478 struct bpf_d *d = fp->f_bpf; 479 int s; 480 481 KERNEL_LOCK(1, NULL); 482 mutex_enter(&bpf_mtx); 483 484 /* 485 * Refresh the PID associated with this bpf file. 486 */ 487 d->bd_pid = curproc->p_pid; 488 489 s = splnet(); 490 if (d->bd_state == BPF_WAITING) 491 callout_stop(&d->bd_callout); 492 d->bd_state = BPF_IDLE; 493 if (d->bd_bif) 494 bpf_detachd(d); 495 splx(s); 496 bpf_freed(d); 497 LIST_REMOVE(d, bd_list); 498 callout_destroy(&d->bd_callout); 499 seldestroy(&d->bd_sel); 500 softint_disestablish(d->bd_sih); 501 free(d, M_DEVBUF); 502 fp->f_bpf = NULL; 503 504 mutex_exit(&bpf_mtx); 505 KERNEL_UNLOCK_ONE(NULL); 506 507 return (0); 508 } 509 510 /* 511 * Rotate the packet buffers in descriptor d. Move the store buffer 512 * into the hold slot, and the free buffer into the store slot. 513 * Zero the length of the new store buffer. 514 */ 515 #define ROTATE_BUFFERS(d) \ 516 (d)->bd_hbuf = (d)->bd_sbuf; \ 517 (d)->bd_hlen = (d)->bd_slen; \ 518 (d)->bd_sbuf = (d)->bd_fbuf; \ 519 (d)->bd_slen = 0; \ 520 (d)->bd_fbuf = NULL; 521 /* 522 * bpfread - read next chunk of packets from buffers 523 */ 524 static int 525 bpf_read(struct file *fp, off_t *offp, struct uio *uio, 526 kauth_cred_t cred, int flags) 527 { 528 struct bpf_d *d = fp->f_bpf; 529 int timed_out; 530 int error; 531 int s; 532 533 getnanotime(&d->bd_atime); 534 /* 535 * Restrict application to use a buffer the same size as 536 * the kernel buffers. 537 */ 538 if (uio->uio_resid != d->bd_bufsize) 539 return (EINVAL); 540 541 KERNEL_LOCK(1, NULL); 542 s = splnet(); 543 if (d->bd_state == BPF_WAITING) 544 callout_stop(&d->bd_callout); 545 timed_out = (d->bd_state == BPF_TIMED_OUT); 546 d->bd_state = BPF_IDLE; 547 /* 548 * If the hold buffer is empty, then do a timed sleep, which 549 * ends when the timeout expires or when enough packets 550 * have arrived to fill the store buffer. 551 */ 552 while (d->bd_hbuf == NULL) { 553 if (fp->f_flag & FNONBLOCK) { 554 if (d->bd_slen == 0) { 555 splx(s); 556 KERNEL_UNLOCK_ONE(NULL); 557 return (EWOULDBLOCK); 558 } 559 ROTATE_BUFFERS(d); 560 break; 561 } 562 563 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 564 /* 565 * A packet(s) either arrived since the previous 566 * read or arrived while we were asleep. 567 * Rotate the buffers and return what's here. 568 */ 569 ROTATE_BUFFERS(d); 570 break; 571 } 572 error = tsleep(d, PRINET|PCATCH, "bpf", 573 d->bd_rtout); 574 if (error == EINTR || error == ERESTART) { 575 splx(s); 576 KERNEL_UNLOCK_ONE(NULL); 577 return (error); 578 } 579 if (error == EWOULDBLOCK) { 580 /* 581 * On a timeout, return what's in the buffer, 582 * which may be nothing. If there is something 583 * in the store buffer, we can rotate the buffers. 584 */ 585 if (d->bd_hbuf) 586 /* 587 * We filled up the buffer in between 588 * getting the timeout and arriving 589 * here, so we don't need to rotate. 590 */ 591 break; 592 593 if (d->bd_slen == 0) { 594 splx(s); 595 KERNEL_UNLOCK_ONE(NULL); 596 return (0); 597 } 598 ROTATE_BUFFERS(d); 599 break; 600 } 601 if (error != 0) 602 goto done; 603 } 604 /* 605 * At this point, we know we have something in the hold slot. 606 */ 607 splx(s); 608 609 /* 610 * Move data from hold buffer into user space. 611 * We know the entire buffer is transferred since 612 * we checked above that the read buffer is bpf_bufsize bytes. 613 */ 614 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 615 616 s = splnet(); 617 d->bd_fbuf = d->bd_hbuf; 618 d->bd_hbuf = NULL; 619 d->bd_hlen = 0; 620 done: 621 splx(s); 622 KERNEL_UNLOCK_ONE(NULL); 623 return (error); 624 } 625 626 627 /* 628 * If there are processes sleeping on this descriptor, wake them up. 629 */ 630 static inline void 631 bpf_wakeup(struct bpf_d *d) 632 { 633 wakeup(d); 634 if (d->bd_async) 635 softint_schedule(d->bd_sih); 636 selnotify(&d->bd_sel, 0, 0); 637 } 638 639 static void 640 bpf_softintr(void *cookie) 641 { 642 struct bpf_d *d; 643 644 d = cookie; 645 if (d->bd_async) 646 fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL); 647 } 648 649 static void 650 bpf_timed_out(void *arg) 651 { 652 struct bpf_d *d = arg; 653 int s; 654 655 s = splnet(); 656 if (d->bd_state == BPF_WAITING) { 657 d->bd_state = BPF_TIMED_OUT; 658 if (d->bd_slen != 0) 659 bpf_wakeup(d); 660 } 661 splx(s); 662 } 663 664 665 static int 666 bpf_write(struct file *fp, off_t *offp, struct uio *uio, 667 kauth_cred_t cred, int flags) 668 { 669 struct bpf_d *d = fp->f_bpf; 670 struct ifnet *ifp; 671 struct mbuf *m, *mc; 672 int error, s; 673 static struct sockaddr_storage dst; 674 675 m = NULL; /* XXX gcc */ 676 677 KERNEL_LOCK(1, NULL); 678 679 if (d->bd_bif == NULL) { 680 KERNEL_UNLOCK_ONE(NULL); 681 return (ENXIO); 682 } 683 getnanotime(&d->bd_mtime); 684 685 ifp = d->bd_bif->bif_ifp; 686 687 if (uio->uio_resid == 0) { 688 KERNEL_UNLOCK_ONE(NULL); 689 return (0); 690 } 691 692 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, &m, 693 (struct sockaddr *) &dst); 694 if (error) { 695 KERNEL_UNLOCK_ONE(NULL); 696 return (error); 697 } 698 699 if (m->m_pkthdr.len > ifp->if_mtu) { 700 KERNEL_UNLOCK_ONE(NULL); 701 m_freem(m); 702 return (EMSGSIZE); 703 } 704 705 if (d->bd_hdrcmplt) 706 dst.ss_family = pseudo_AF_HDRCMPLT; 707 708 if (d->bd_feedback) { 709 mc = m_dup(m, 0, M_COPYALL, M_NOWAIT); 710 if (mc != NULL) 711 mc->m_pkthdr.rcvif = ifp; 712 /* Set M_PROMISC for outgoing packets to be discarded. */ 713 if (1 /*d->bd_direction == BPF_D_INOUT*/) 714 m->m_flags |= M_PROMISC; 715 } else 716 mc = NULL; 717 718 s = splsoftnet(); 719 error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL); 720 721 if (mc != NULL) { 722 if (error == 0) 723 (*ifp->if_input)(ifp, mc); 724 m_freem(mc); 725 } 726 splx(s); 727 KERNEL_UNLOCK_ONE(NULL); 728 /* 729 * The driver frees the mbuf. 730 */ 731 return (error); 732 } 733 734 /* 735 * Reset a descriptor by flushing its packet buffer and clearing the 736 * receive and drop counts. Should be called at splnet. 737 */ 738 static void 739 reset_d(struct bpf_d *d) 740 { 741 if (d->bd_hbuf) { 742 /* Free the hold buffer. */ 743 d->bd_fbuf = d->bd_hbuf; 744 d->bd_hbuf = NULL; 745 } 746 d->bd_slen = 0; 747 d->bd_hlen = 0; 748 d->bd_rcount = 0; 749 d->bd_dcount = 0; 750 d->bd_ccount = 0; 751 } 752 753 /* 754 * FIONREAD Check for read packet available. 755 * BIOCGBLEN Get buffer len [for read()]. 756 * BIOCSETF Set ethernet read filter. 757 * BIOCFLUSH Flush read packet buffer. 758 * BIOCPROMISC Put interface into promiscuous mode. 759 * BIOCGDLT Get link layer type. 760 * BIOCGETIF Get interface name. 761 * BIOCSETIF Set interface. 762 * BIOCSRTIMEOUT Set read timeout. 763 * BIOCGRTIMEOUT Get read timeout. 764 * BIOCGSTATS Get packet stats. 765 * BIOCIMMEDIATE Set immediate mode. 766 * BIOCVERSION Get filter language version. 767 * BIOCGHDRCMPLT Get "header already complete" flag. 768 * BIOCSHDRCMPLT Set "header already complete" flag. 769 * BIOCSFEEDBACK Set packet feedback mode. 770 * BIOCGFEEDBACK Get packet feedback mode. 771 * BIOCGSEESENT Get "see sent packets" mode. 772 * BIOCSSEESENT Set "see sent packets" mode. 773 */ 774 /* ARGSUSED */ 775 static int 776 bpf_ioctl(struct file *fp, u_long cmd, void *addr) 777 { 778 struct bpf_d *d = fp->f_bpf; 779 int s, error = 0; 780 781 /* 782 * Refresh the PID associated with this bpf file. 783 */ 784 KERNEL_LOCK(1, NULL); 785 d->bd_pid = curproc->p_pid; 786 #ifdef _LP64 787 if (curproc->p_flag & PK_32) 788 d->bd_compat32 = 1; 789 else 790 d->bd_compat32 = 0; 791 #endif 792 793 s = splnet(); 794 if (d->bd_state == BPF_WAITING) 795 callout_stop(&d->bd_callout); 796 d->bd_state = BPF_IDLE; 797 splx(s); 798 799 switch (cmd) { 800 801 default: 802 error = EINVAL; 803 break; 804 805 /* 806 * Check for read packet available. 807 */ 808 case FIONREAD: 809 { 810 int n; 811 812 s = splnet(); 813 n = d->bd_slen; 814 if (d->bd_hbuf) 815 n += d->bd_hlen; 816 splx(s); 817 818 *(int *)addr = n; 819 break; 820 } 821 822 /* 823 * Get buffer len [for read()]. 824 */ 825 case BIOCGBLEN: 826 *(u_int *)addr = d->bd_bufsize; 827 break; 828 829 /* 830 * Set buffer length. 831 */ 832 case BIOCSBLEN: 833 if (d->bd_bif != NULL) 834 error = EINVAL; 835 else { 836 u_int size = *(u_int *)addr; 837 838 if (size > bpf_maxbufsize) 839 *(u_int *)addr = size = bpf_maxbufsize; 840 else if (size < BPF_MINBUFSIZE) 841 *(u_int *)addr = size = BPF_MINBUFSIZE; 842 d->bd_bufsize = size; 843 } 844 break; 845 846 /* 847 * Set link layer read filter. 848 */ 849 case BIOCSETF: 850 error = bpf_setf(d, addr); 851 break; 852 853 /* 854 * Flush read packet buffer. 855 */ 856 case BIOCFLUSH: 857 s = splnet(); 858 reset_d(d); 859 splx(s); 860 break; 861 862 /* 863 * Put interface into promiscuous mode. 864 */ 865 case BIOCPROMISC: 866 if (d->bd_bif == NULL) { 867 /* 868 * No interface attached yet. 869 */ 870 error = EINVAL; 871 break; 872 } 873 s = splnet(); 874 if (d->bd_promisc == 0) { 875 error = ifpromisc(d->bd_bif->bif_ifp, 1); 876 if (error == 0) 877 d->bd_promisc = 1; 878 } 879 splx(s); 880 break; 881 882 /* 883 * Get device parameters. 884 */ 885 case BIOCGDLT: 886 if (d->bd_bif == NULL) 887 error = EINVAL; 888 else 889 *(u_int *)addr = d->bd_bif->bif_dlt; 890 break; 891 892 /* 893 * Get a list of supported device parameters. 894 */ 895 case BIOCGDLTLIST: 896 if (d->bd_bif == NULL) 897 error = EINVAL; 898 else 899 error = bpf_getdltlist(d, addr); 900 break; 901 902 /* 903 * Set device parameters. 904 */ 905 case BIOCSDLT: 906 mutex_enter(&bpf_mtx); 907 if (d->bd_bif == NULL) 908 error = EINVAL; 909 else 910 error = bpf_setdlt(d, *(u_int *)addr); 911 mutex_exit(&bpf_mtx); 912 break; 913 914 /* 915 * Set interface name. 916 */ 917 #ifdef OBIOCGETIF 918 case OBIOCGETIF: 919 #endif 920 case BIOCGETIF: 921 if (d->bd_bif == NULL) 922 error = EINVAL; 923 else 924 bpf_ifname(d->bd_bif->bif_ifp, addr); 925 break; 926 927 /* 928 * Set interface. 929 */ 930 #ifdef OBIOCSETIF 931 case OBIOCSETIF: 932 #endif 933 case BIOCSETIF: 934 mutex_enter(&bpf_mtx); 935 error = bpf_setif(d, addr); 936 mutex_exit(&bpf_mtx); 937 break; 938 939 /* 940 * Set read timeout. 941 */ 942 case BIOCSRTIMEOUT: 943 { 944 struct timeval *tv = addr; 945 946 /* Compute number of ticks. */ 947 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 948 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 949 d->bd_rtout = 1; 950 break; 951 } 952 953 #ifdef BIOCGORTIMEOUT 954 /* 955 * Get read timeout. 956 */ 957 case BIOCGORTIMEOUT: 958 { 959 struct timeval50 *tv = addr; 960 961 tv->tv_sec = d->bd_rtout / hz; 962 tv->tv_usec = (d->bd_rtout % hz) * tick; 963 break; 964 } 965 #endif 966 967 #ifdef BIOCSORTIMEOUT 968 /* 969 * Set read timeout. 970 */ 971 case BIOCSORTIMEOUT: 972 { 973 struct timeval50 *tv = addr; 974 975 /* Compute number of ticks. */ 976 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 977 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 978 d->bd_rtout = 1; 979 break; 980 } 981 #endif 982 983 /* 984 * Get read timeout. 985 */ 986 case BIOCGRTIMEOUT: 987 { 988 struct timeval *tv = addr; 989 990 tv->tv_sec = d->bd_rtout / hz; 991 tv->tv_usec = (d->bd_rtout % hz) * tick; 992 break; 993 } 994 /* 995 * Get packet stats. 996 */ 997 case BIOCGSTATS: 998 { 999 struct bpf_stat *bs = addr; 1000 1001 bs->bs_recv = d->bd_rcount; 1002 bs->bs_drop = d->bd_dcount; 1003 bs->bs_capt = d->bd_ccount; 1004 break; 1005 } 1006 1007 case BIOCGSTATSOLD: 1008 { 1009 struct bpf_stat_old *bs = addr; 1010 1011 bs->bs_recv = d->bd_rcount; 1012 bs->bs_drop = d->bd_dcount; 1013 break; 1014 } 1015 1016 /* 1017 * Set immediate mode. 1018 */ 1019 case BIOCIMMEDIATE: 1020 d->bd_immediate = *(u_int *)addr; 1021 break; 1022 1023 case BIOCVERSION: 1024 { 1025 struct bpf_version *bv = addr; 1026 1027 bv->bv_major = BPF_MAJOR_VERSION; 1028 bv->bv_minor = BPF_MINOR_VERSION; 1029 break; 1030 } 1031 1032 case BIOCGHDRCMPLT: /* get "header already complete" flag */ 1033 *(u_int *)addr = d->bd_hdrcmplt; 1034 break; 1035 1036 case BIOCSHDRCMPLT: /* set "header already complete" flag */ 1037 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 1038 break; 1039 1040 /* 1041 * Get "see sent packets" flag 1042 */ 1043 case BIOCGSEESENT: 1044 *(u_int *)addr = d->bd_seesent; 1045 break; 1046 1047 /* 1048 * Set "see sent" packets flag 1049 */ 1050 case BIOCSSEESENT: 1051 d->bd_seesent = *(u_int *)addr; 1052 break; 1053 1054 /* 1055 * Set "feed packets from bpf back to input" mode 1056 */ 1057 case BIOCSFEEDBACK: 1058 d->bd_feedback = *(u_int *)addr; 1059 break; 1060 1061 /* 1062 * Get "feed packets from bpf back to input" mode 1063 */ 1064 case BIOCGFEEDBACK: 1065 *(u_int *)addr = d->bd_feedback; 1066 break; 1067 1068 case FIONBIO: /* Non-blocking I/O */ 1069 /* 1070 * No need to do anything special as we use IO_NDELAY in 1071 * bpfread() as an indication of whether or not to block 1072 * the read. 1073 */ 1074 break; 1075 1076 case FIOASYNC: /* Send signal on receive packets */ 1077 d->bd_async = *(int *)addr; 1078 break; 1079 1080 case TIOCSPGRP: /* Process or group to send signals to */ 1081 case FIOSETOWN: 1082 error = fsetown(&d->bd_pgid, cmd, addr); 1083 break; 1084 1085 case TIOCGPGRP: 1086 case FIOGETOWN: 1087 error = fgetown(d->bd_pgid, cmd, addr); 1088 break; 1089 } 1090 KERNEL_UNLOCK_ONE(NULL); 1091 return (error); 1092 } 1093 1094 /* 1095 * Set d's packet filter program to fp. If this file already has a filter, 1096 * free it and replace it. Returns EINVAL for bogus requests. 1097 */ 1098 int 1099 bpf_setf(struct bpf_d *d, struct bpf_program *fp) 1100 { 1101 struct bpf_insn *fcode, *old; 1102 bpfjit_func_t jcode, oldj; 1103 size_t flen, size; 1104 int s; 1105 1106 jcode = NULL; 1107 flen = fp->bf_len; 1108 1109 if ((fp->bf_insns == NULL && flen) || flen > BPF_MAXINSNS) { 1110 return EINVAL; 1111 } 1112 1113 if (flen) { 1114 /* 1115 * Allocate the buffer, copy the byte-code from 1116 * userspace and validate it. 1117 */ 1118 size = flen * sizeof(*fp->bf_insns); 1119 fcode = malloc(size, M_DEVBUF, M_WAITOK); 1120 if (copyin(fp->bf_insns, fcode, size) != 0 || 1121 !bpf_validate(fcode, (int)flen)) { 1122 free(fcode, M_DEVBUF); 1123 return EINVAL; 1124 } 1125 membar_consumer(); 1126 if (bpf_jit) 1127 jcode = bpf_jit_generate(NULL, fcode, flen); 1128 } else { 1129 fcode = NULL; 1130 } 1131 1132 s = splnet(); 1133 old = d->bd_filter; 1134 d->bd_filter = fcode; 1135 oldj = d->bd_jitcode; 1136 d->bd_jitcode = jcode; 1137 reset_d(d); 1138 splx(s); 1139 1140 if (old) { 1141 free(old, M_DEVBUF); 1142 } 1143 if (oldj) { 1144 bpf_jit_freecode(oldj); 1145 } 1146 1147 return 0; 1148 } 1149 1150 /* 1151 * Detach a file from its current interface (if attached at all) and attach 1152 * to the interface indicated by the name stored in ifr. 1153 * Return an errno or 0. 1154 */ 1155 static int 1156 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 1157 { 1158 struct bpf_if *bp; 1159 char *cp; 1160 int unit_seen, i, s, error; 1161 1162 KASSERT(mutex_owned(&bpf_mtx)); 1163 /* 1164 * Make sure the provided name has a unit number, and default 1165 * it to '0' if not specified. 1166 * XXX This is ugly ... do this differently? 1167 */ 1168 unit_seen = 0; 1169 cp = ifr->ifr_name; 1170 cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */ 1171 while (*cp++) 1172 if (*cp >= '0' && *cp <= '9') 1173 unit_seen = 1; 1174 if (!unit_seen) { 1175 /* Make sure to leave room for the '\0'. */ 1176 for (i = 0; i < (IFNAMSIZ - 1); ++i) { 1177 if ((ifr->ifr_name[i] >= 'a' && 1178 ifr->ifr_name[i] <= 'z') || 1179 (ifr->ifr_name[i] >= 'A' && 1180 ifr->ifr_name[i] <= 'Z')) 1181 continue; 1182 ifr->ifr_name[i] = '0'; 1183 } 1184 } 1185 1186 /* 1187 * Look through attached interfaces for the named one. 1188 */ 1189 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1190 struct ifnet *ifp = bp->bif_ifp; 1191 1192 if (ifp == NULL || 1193 strcmp(ifp->if_xname, ifr->ifr_name) != 0) 1194 continue; 1195 /* skip additional entry */ 1196 if (bp->bif_driverp != &ifp->if_bpf) 1197 continue; 1198 /* 1199 * We found the requested interface. 1200 * Allocate the packet buffers if we need to. 1201 * If we're already attached to requested interface, 1202 * just flush the buffer. 1203 */ 1204 if (d->bd_sbuf == NULL) { 1205 error = bpf_allocbufs(d); 1206 if (error != 0) 1207 return (error); 1208 } 1209 s = splnet(); 1210 if (bp != d->bd_bif) { 1211 if (d->bd_bif) 1212 /* 1213 * Detach if attached to something else. 1214 */ 1215 bpf_detachd(d); 1216 1217 bpf_attachd(d, bp); 1218 } 1219 reset_d(d); 1220 splx(s); 1221 return (0); 1222 } 1223 /* Not found. */ 1224 return (ENXIO); 1225 } 1226 1227 /* 1228 * Copy the interface name to the ifreq. 1229 */ 1230 static void 1231 bpf_ifname(struct ifnet *ifp, struct ifreq *ifr) 1232 { 1233 memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1234 } 1235 1236 static int 1237 bpf_stat(struct file *fp, struct stat *st) 1238 { 1239 struct bpf_d *d = fp->f_bpf; 1240 1241 (void)memset(st, 0, sizeof(*st)); 1242 KERNEL_LOCK(1, NULL); 1243 st->st_dev = makedev(cdevsw_lookup_major(&bpf_cdevsw), d->bd_pid); 1244 st->st_atimespec = d->bd_atime; 1245 st->st_mtimespec = d->bd_mtime; 1246 st->st_ctimespec = st->st_birthtimespec = d->bd_btime; 1247 st->st_uid = kauth_cred_geteuid(fp->f_cred); 1248 st->st_gid = kauth_cred_getegid(fp->f_cred); 1249 st->st_mode = S_IFCHR; 1250 KERNEL_UNLOCK_ONE(NULL); 1251 return 0; 1252 } 1253 1254 /* 1255 * Support for poll() system call 1256 * 1257 * Return true iff the specific operation will not block indefinitely - with 1258 * the assumption that it is safe to positively acknowledge a request for the 1259 * ability to write to the BPF device. 1260 * Otherwise, return false but make a note that a selnotify() must be done. 1261 */ 1262 static int 1263 bpf_poll(struct file *fp, int events) 1264 { 1265 struct bpf_d *d = fp->f_bpf; 1266 int s = splnet(); 1267 int revents; 1268 1269 /* 1270 * Refresh the PID associated with this bpf file. 1271 */ 1272 KERNEL_LOCK(1, NULL); 1273 d->bd_pid = curproc->p_pid; 1274 1275 revents = events & (POLLOUT | POLLWRNORM); 1276 if (events & (POLLIN | POLLRDNORM)) { 1277 /* 1278 * An imitation of the FIONREAD ioctl code. 1279 */ 1280 if (d->bd_hlen != 0 || 1281 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) && 1282 d->bd_slen != 0)) { 1283 revents |= events & (POLLIN | POLLRDNORM); 1284 } else { 1285 selrecord(curlwp, &d->bd_sel); 1286 /* Start the read timeout if necessary */ 1287 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1288 callout_reset(&d->bd_callout, d->bd_rtout, 1289 bpf_timed_out, d); 1290 d->bd_state = BPF_WAITING; 1291 } 1292 } 1293 } 1294 1295 KERNEL_UNLOCK_ONE(NULL); 1296 splx(s); 1297 return (revents); 1298 } 1299 1300 static void 1301 filt_bpfrdetach(struct knote *kn) 1302 { 1303 struct bpf_d *d = kn->kn_hook; 1304 int s; 1305 1306 KERNEL_LOCK(1, NULL); 1307 s = splnet(); 1308 SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext); 1309 splx(s); 1310 KERNEL_UNLOCK_ONE(NULL); 1311 } 1312 1313 static int 1314 filt_bpfread(struct knote *kn, long hint) 1315 { 1316 struct bpf_d *d = kn->kn_hook; 1317 int rv; 1318 1319 KERNEL_LOCK(1, NULL); 1320 kn->kn_data = d->bd_hlen; 1321 if (d->bd_immediate) 1322 kn->kn_data += d->bd_slen; 1323 rv = (kn->kn_data > 0); 1324 KERNEL_UNLOCK_ONE(NULL); 1325 return rv; 1326 } 1327 1328 static const struct filterops bpfread_filtops = 1329 { 1, NULL, filt_bpfrdetach, filt_bpfread }; 1330 1331 static int 1332 bpf_kqfilter(struct file *fp, struct knote *kn) 1333 { 1334 struct bpf_d *d = fp->f_bpf; 1335 struct klist *klist; 1336 int s; 1337 1338 KERNEL_LOCK(1, NULL); 1339 1340 switch (kn->kn_filter) { 1341 case EVFILT_READ: 1342 klist = &d->bd_sel.sel_klist; 1343 kn->kn_fop = &bpfread_filtops; 1344 break; 1345 1346 default: 1347 KERNEL_UNLOCK_ONE(NULL); 1348 return (EINVAL); 1349 } 1350 1351 kn->kn_hook = d; 1352 1353 s = splnet(); 1354 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 1355 splx(s); 1356 KERNEL_UNLOCK_ONE(NULL); 1357 1358 return (0); 1359 } 1360 1361 /* 1362 * Copy data from an mbuf chain into a buffer. This code is derived 1363 * from m_copydata in sys/uipc_mbuf.c. 1364 */ 1365 static void * 1366 bpf_mcpy(void *dst_arg, const void *src_arg, size_t len) 1367 { 1368 const struct mbuf *m; 1369 u_int count; 1370 u_char *dst; 1371 1372 m = src_arg; 1373 dst = dst_arg; 1374 while (len > 0) { 1375 if (m == NULL) 1376 panic("bpf_mcpy"); 1377 count = min(m->m_len, len); 1378 memcpy(dst, mtod(m, const void *), count); 1379 m = m->m_next; 1380 dst += count; 1381 len -= count; 1382 } 1383 return dst_arg; 1384 } 1385 1386 /* 1387 * Dispatch a packet to all the listeners on interface bp. 1388 * 1389 * pkt pointer to the packet, either a data buffer or an mbuf chain 1390 * buflen buffer length, if pkt is a data buffer 1391 * cpfn a function that can copy pkt into the listener's buffer 1392 * pktlen length of the packet 1393 * rcv true if packet came in 1394 */ 1395 static inline void 1396 bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t), 1397 void *pkt, u_int pktlen, u_int buflen, const bool rcv) 1398 { 1399 uint32_t mem[BPF_MEMWORDS]; 1400 bpf_args_t args = { 1401 .pkt = (const uint8_t *)pkt, 1402 .wirelen = pktlen, 1403 .buflen = buflen, 1404 .mem = mem, 1405 .arg = NULL 1406 }; 1407 bool gottime = false; 1408 struct timespec ts; 1409 1410 /* 1411 * Note that the IPL does not have to be raised at this point. 1412 * The only problem that could arise here is that if two different 1413 * interfaces shared any data. This is not the case. 1414 */ 1415 for (struct bpf_d *d = bp->bif_dlist; d != NULL; d = d->bd_next) { 1416 u_int slen; 1417 1418 if (!d->bd_seesent && !rcv) { 1419 continue; 1420 } 1421 d->bd_rcount++; 1422 bpf_gstats.bs_recv++; 1423 1424 if (d->bd_jitcode) 1425 slen = d->bd_jitcode(NULL, &args); 1426 else 1427 slen = bpf_filter_ext(NULL, d->bd_filter, &args); 1428 1429 if (!slen) { 1430 continue; 1431 } 1432 if (!gottime) { 1433 gottime = true; 1434 nanotime(&ts); 1435 } 1436 catchpacket(d, pkt, pktlen, slen, cpfn, &ts); 1437 } 1438 } 1439 1440 /* 1441 * Incoming linkage from device drivers. Process the packet pkt, of length 1442 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1443 * by each process' filter, and if accepted, stashed into the corresponding 1444 * buffer. 1445 */ 1446 static void 1447 _bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1448 { 1449 1450 bpf_deliver(bp, memcpy, pkt, pktlen, pktlen, true); 1451 } 1452 1453 /* 1454 * Incoming linkage from device drivers, when the head of the packet is in 1455 * a buffer, and the tail is in an mbuf chain. 1456 */ 1457 static void 1458 _bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) 1459 { 1460 u_int pktlen; 1461 struct mbuf mb; 1462 1463 /* Skip outgoing duplicate packets. */ 1464 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) { 1465 m->m_flags &= ~M_PROMISC; 1466 return; 1467 } 1468 1469 pktlen = m_length(m) + dlen; 1470 1471 /* 1472 * Craft on-stack mbuf suitable for passing to bpf_filter. 1473 * Note that we cut corners here; we only setup what's 1474 * absolutely needed--this mbuf should never go anywhere else. 1475 */ 1476 (void)memset(&mb, 0, sizeof(mb)); 1477 mb.m_next = m; 1478 mb.m_data = data; 1479 mb.m_len = dlen; 1480 1481 bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif != NULL); 1482 } 1483 1484 /* 1485 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1486 */ 1487 static void 1488 _bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1489 { 1490 void *(*cpfn)(void *, const void *, size_t); 1491 u_int pktlen, buflen; 1492 void *marg; 1493 1494 /* Skip outgoing duplicate packets. */ 1495 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) { 1496 m->m_flags &= ~M_PROMISC; 1497 return; 1498 } 1499 1500 pktlen = m_length(m); 1501 1502 if (pktlen == m->m_len) { 1503 cpfn = (void *)memcpy; 1504 marg = mtod(m, void *); 1505 buflen = pktlen; 1506 } else { 1507 cpfn = bpf_mcpy; 1508 marg = m; 1509 buflen = 0; 1510 } 1511 1512 bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif != NULL); 1513 } 1514 1515 /* 1516 * We need to prepend the address family as 1517 * a four byte field. Cons up a dummy header 1518 * to pacify bpf. This is safe because bpf 1519 * will only read from the mbuf (i.e., it won't 1520 * try to free it or keep a pointer a to it). 1521 */ 1522 static void 1523 _bpf_mtap_af(struct bpf_if *bp, uint32_t af, struct mbuf *m) 1524 { 1525 struct mbuf m0; 1526 1527 m0.m_flags = 0; 1528 m0.m_next = m; 1529 m0.m_len = 4; 1530 m0.m_data = (char *)⁡ 1531 1532 _bpf_mtap(bp, &m0); 1533 } 1534 1535 /* 1536 * Put the SLIP pseudo-"link header" in place. 1537 * Note this M_PREPEND() should never fail, 1538 * swince we know we always have enough space 1539 * in the input buffer. 1540 */ 1541 static void 1542 _bpf_mtap_sl_in(struct bpf_if *bp, u_char *chdr, struct mbuf **m) 1543 { 1544 int s; 1545 u_char *hp; 1546 1547 M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT); 1548 if (*m == NULL) 1549 return; 1550 1551 hp = mtod(*m, u_char *); 1552 hp[SLX_DIR] = SLIPDIR_IN; 1553 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1554 1555 s = splnet(); 1556 _bpf_mtap(bp, *m); 1557 splx(s); 1558 1559 m_adj(*m, SLIP_HDRLEN); 1560 } 1561 1562 /* 1563 * Put the SLIP pseudo-"link header" in 1564 * place. The compressed header is now 1565 * at the beginning of the mbuf. 1566 */ 1567 static void 1568 _bpf_mtap_sl_out(struct bpf_if *bp, u_char *chdr, struct mbuf *m) 1569 { 1570 struct mbuf m0; 1571 u_char *hp; 1572 int s; 1573 1574 m0.m_flags = 0; 1575 m0.m_next = m; 1576 m0.m_data = m0.m_dat; 1577 m0.m_len = SLIP_HDRLEN; 1578 1579 hp = mtod(&m0, u_char *); 1580 1581 hp[SLX_DIR] = SLIPDIR_OUT; 1582 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1583 1584 s = splnet(); 1585 _bpf_mtap(bp, &m0); 1586 splx(s); 1587 m_freem(m); 1588 } 1589 1590 static int 1591 bpf_hdrlen(struct bpf_d *d) 1592 { 1593 int hdrlen = d->bd_bif->bif_hdrlen; 1594 /* 1595 * Compute the length of the bpf header. This is not necessarily 1596 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1597 * that the network layer header begins on a longword boundary (for 1598 * performance reasons and to alleviate alignment restrictions). 1599 */ 1600 #ifdef _LP64 1601 if (d->bd_compat32) 1602 return (BPF_WORDALIGN32(hdrlen + SIZEOF_BPF_HDR32) - hdrlen); 1603 else 1604 #endif 1605 return (BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen); 1606 } 1607 1608 /* 1609 * Move the packet data from interface memory (pkt) into the 1610 * store buffer. Call the wakeup functions if it's time to wakeup 1611 * a listener (buffer full), "cpfn" is the routine called to do the 1612 * actual data transfer. memcpy is passed in to copy contiguous chunks, 1613 * while bpf_mcpy is passed in to copy mbuf chains. In the latter case, 1614 * pkt is really an mbuf. 1615 */ 1616 static void 1617 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1618 void *(*cpfn)(void *, const void *, size_t), struct timespec *ts) 1619 { 1620 char *h; 1621 int totlen, curlen, caplen; 1622 int hdrlen = bpf_hdrlen(d); 1623 int do_wakeup = 0; 1624 1625 ++d->bd_ccount; 1626 ++bpf_gstats.bs_capt; 1627 /* 1628 * Figure out how many bytes to move. If the packet is 1629 * greater or equal to the snapshot length, transfer that 1630 * much. Otherwise, transfer the whole packet (unless 1631 * we hit the buffer size limit). 1632 */ 1633 totlen = hdrlen + min(snaplen, pktlen); 1634 if (totlen > d->bd_bufsize) 1635 totlen = d->bd_bufsize; 1636 /* 1637 * If we adjusted totlen to fit the bufsize, it could be that 1638 * totlen is smaller than hdrlen because of the link layer header. 1639 */ 1640 caplen = totlen - hdrlen; 1641 if (caplen < 0) 1642 caplen = 0; 1643 1644 /* 1645 * Round up the end of the previous packet to the next longword. 1646 */ 1647 #ifdef _LP64 1648 if (d->bd_compat32) 1649 curlen = BPF_WORDALIGN32(d->bd_slen); 1650 else 1651 #endif 1652 curlen = BPF_WORDALIGN(d->bd_slen); 1653 if (curlen + totlen > d->bd_bufsize) { 1654 /* 1655 * This packet will overflow the storage buffer. 1656 * Rotate the buffers if we can, then wakeup any 1657 * pending reads. 1658 */ 1659 if (d->bd_fbuf == NULL) { 1660 /* 1661 * We haven't completed the previous read yet, 1662 * so drop the packet. 1663 */ 1664 ++d->bd_dcount; 1665 ++bpf_gstats.bs_drop; 1666 return; 1667 } 1668 ROTATE_BUFFERS(d); 1669 do_wakeup = 1; 1670 curlen = 0; 1671 } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) { 1672 /* 1673 * Immediate mode is set, or the read timeout has 1674 * already expired during a select call. A packet 1675 * arrived, so the reader should be woken up. 1676 */ 1677 do_wakeup = 1; 1678 } 1679 1680 /* 1681 * Append the bpf header. 1682 */ 1683 h = (char *)d->bd_sbuf + curlen; 1684 #ifdef _LP64 1685 if (d->bd_compat32) { 1686 struct bpf_hdr32 *hp32; 1687 1688 hp32 = (struct bpf_hdr32 *)h; 1689 hp32->bh_tstamp.tv_sec = ts->tv_sec; 1690 hp32->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1691 hp32->bh_datalen = pktlen; 1692 hp32->bh_hdrlen = hdrlen; 1693 hp32->bh_caplen = caplen; 1694 } else 1695 #endif 1696 { 1697 struct bpf_hdr *hp; 1698 1699 hp = (struct bpf_hdr *)h; 1700 hp->bh_tstamp.tv_sec = ts->tv_sec; 1701 hp->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1702 hp->bh_datalen = pktlen; 1703 hp->bh_hdrlen = hdrlen; 1704 hp->bh_caplen = caplen; 1705 } 1706 1707 /* 1708 * Copy the packet data into the store buffer and update its length. 1709 */ 1710 (*cpfn)(h + hdrlen, pkt, caplen); 1711 d->bd_slen = curlen + totlen; 1712 1713 /* 1714 * Call bpf_wakeup after bd_slen has been updated so that kevent(2) 1715 * will cause filt_bpfread() to be called with it adjusted. 1716 */ 1717 if (do_wakeup) 1718 bpf_wakeup(d); 1719 } 1720 1721 /* 1722 * Initialize all nonzero fields of a descriptor. 1723 */ 1724 static int 1725 bpf_allocbufs(struct bpf_d *d) 1726 { 1727 1728 d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT); 1729 if (!d->bd_fbuf) 1730 return (ENOBUFS); 1731 d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_NOWAIT); 1732 if (!d->bd_sbuf) { 1733 free(d->bd_fbuf, M_DEVBUF); 1734 return (ENOBUFS); 1735 } 1736 d->bd_slen = 0; 1737 d->bd_hlen = 0; 1738 return (0); 1739 } 1740 1741 /* 1742 * Free buffers currently in use by a descriptor. 1743 * Called on close. 1744 */ 1745 static void 1746 bpf_freed(struct bpf_d *d) 1747 { 1748 /* 1749 * We don't need to lock out interrupts since this descriptor has 1750 * been detached from its interface and it yet hasn't been marked 1751 * free. 1752 */ 1753 if (d->bd_sbuf != NULL) { 1754 free(d->bd_sbuf, M_DEVBUF); 1755 if (d->bd_hbuf != NULL) 1756 free(d->bd_hbuf, M_DEVBUF); 1757 if (d->bd_fbuf != NULL) 1758 free(d->bd_fbuf, M_DEVBUF); 1759 } 1760 if (d->bd_filter) 1761 free(d->bd_filter, M_DEVBUF); 1762 1763 if (d->bd_jitcode != NULL) { 1764 bpf_jit_freecode(d->bd_jitcode); 1765 } 1766 } 1767 1768 /* 1769 * Attach an interface to bpf. dlt is the link layer type; 1770 * hdrlen is the fixed size of the link header for the specified dlt 1771 * (variable length headers not yet supported). 1772 */ 1773 static void 1774 _bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1775 { 1776 struct bpf_if *bp; 1777 bp = malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1778 if (bp == NULL) 1779 panic("bpfattach"); 1780 1781 mutex_enter(&bpf_mtx); 1782 bp->bif_dlist = NULL; 1783 bp->bif_driverp = driverp; 1784 bp->bif_ifp = ifp; 1785 bp->bif_dlt = dlt; 1786 1787 bp->bif_next = bpf_iflist; 1788 bpf_iflist = bp; 1789 1790 *bp->bif_driverp = NULL; 1791 1792 bp->bif_hdrlen = hdrlen; 1793 mutex_exit(&bpf_mtx); 1794 #if 0 1795 printf("bpf: %s attached\n", ifp->if_xname); 1796 #endif 1797 } 1798 1799 /* 1800 * Remove an interface from bpf. 1801 */ 1802 static void 1803 _bpfdetach(struct ifnet *ifp) 1804 { 1805 struct bpf_if *bp, **pbp; 1806 struct bpf_d *d; 1807 int s; 1808 1809 mutex_enter(&bpf_mtx); 1810 /* Nuke the vnodes for any open instances */ 1811 LIST_FOREACH(d, &bpf_list, bd_list) { 1812 if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) { 1813 /* 1814 * Detach the descriptor from an interface now. 1815 * It will be free'ed later by close routine. 1816 */ 1817 s = splnet(); 1818 d->bd_promisc = 0; /* we can't touch device. */ 1819 bpf_detachd(d); 1820 splx(s); 1821 } 1822 } 1823 1824 again: 1825 for (bp = bpf_iflist, pbp = &bpf_iflist; 1826 bp != NULL; pbp = &bp->bif_next, bp = bp->bif_next) { 1827 if (bp->bif_ifp == ifp) { 1828 *pbp = bp->bif_next; 1829 free(bp, M_DEVBUF); 1830 goto again; 1831 } 1832 } 1833 mutex_exit(&bpf_mtx); 1834 } 1835 1836 /* 1837 * Change the data link type of a interface. 1838 */ 1839 static void 1840 _bpf_change_type(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1841 { 1842 struct bpf_if *bp; 1843 1844 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1845 if (bp->bif_driverp == &ifp->if_bpf) 1846 break; 1847 } 1848 if (bp == NULL) 1849 panic("bpf_change_type"); 1850 1851 bp->bif_dlt = dlt; 1852 1853 bp->bif_hdrlen = hdrlen; 1854 } 1855 1856 /* 1857 * Get a list of available data link type of the interface. 1858 */ 1859 static int 1860 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 1861 { 1862 int n, error; 1863 struct ifnet *ifp; 1864 struct bpf_if *bp; 1865 1866 ifp = d->bd_bif->bif_ifp; 1867 n = 0; 1868 error = 0; 1869 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1870 if (bp->bif_ifp != ifp) 1871 continue; 1872 if (bfl->bfl_list != NULL) { 1873 if (n >= bfl->bfl_len) 1874 return ENOMEM; 1875 error = copyout(&bp->bif_dlt, 1876 bfl->bfl_list + n, sizeof(u_int)); 1877 } 1878 n++; 1879 } 1880 bfl->bfl_len = n; 1881 return error; 1882 } 1883 1884 /* 1885 * Set the data link type of a BPF instance. 1886 */ 1887 static int 1888 bpf_setdlt(struct bpf_d *d, u_int dlt) 1889 { 1890 int s, error, opromisc; 1891 struct ifnet *ifp; 1892 struct bpf_if *bp; 1893 1894 KASSERT(mutex_owned(&bpf_mtx)); 1895 1896 if (d->bd_bif->bif_dlt == dlt) 1897 return 0; 1898 ifp = d->bd_bif->bif_ifp; 1899 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1900 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1901 break; 1902 } 1903 if (bp == NULL) 1904 return EINVAL; 1905 s = splnet(); 1906 opromisc = d->bd_promisc; 1907 bpf_detachd(d); 1908 bpf_attachd(d, bp); 1909 reset_d(d); 1910 if (opromisc) { 1911 error = ifpromisc(bp->bif_ifp, 1); 1912 if (error) 1913 printf("%s: bpf_setdlt: ifpromisc failed (%d)\n", 1914 bp->bif_ifp->if_xname, error); 1915 else 1916 d->bd_promisc = 1; 1917 } 1918 splx(s); 1919 return 0; 1920 } 1921 1922 static int 1923 sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS) 1924 { 1925 int newsize, error; 1926 struct sysctlnode node; 1927 1928 node = *rnode; 1929 node.sysctl_data = &newsize; 1930 newsize = bpf_maxbufsize; 1931 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1932 if (error || newp == NULL) 1933 return (error); 1934 1935 if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE) 1936 return (EINVAL); 1937 1938 bpf_maxbufsize = newsize; 1939 1940 return (0); 1941 } 1942 1943 #if defined(MODULAR) || defined(BPFJIT) 1944 static int 1945 sysctl_net_bpf_jit(SYSCTLFN_ARGS) 1946 { 1947 bool newval; 1948 int error; 1949 struct sysctlnode node; 1950 1951 node = *rnode; 1952 node.sysctl_data = &newval; 1953 newval = bpf_jit; 1954 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1955 if (error != 0 || newp == NULL) 1956 return error; 1957 1958 bpf_jit = newval; 1959 1960 /* 1961 * Do a full sync to publish new bpf_jit value and 1962 * update bpfjit_module_ops.bj_generate_code variable. 1963 */ 1964 membar_sync(); 1965 1966 if (newval && bpfjit_module_ops.bj_generate_code == NULL) { 1967 printf("JIT compilation is postponed " 1968 "until after bpfjit module is loaded\n"); 1969 } 1970 1971 return 0; 1972 } 1973 #endif 1974 1975 static int 1976 sysctl_net_bpf_peers(SYSCTLFN_ARGS) 1977 { 1978 int error, elem_count; 1979 struct bpf_d *dp; 1980 struct bpf_d_ext dpe; 1981 size_t len, needed, elem_size, out_size; 1982 char *sp; 1983 1984 if (namelen == 1 && name[0] == CTL_QUERY) 1985 return (sysctl_query(SYSCTLFN_CALL(rnode))); 1986 1987 if (namelen != 2) 1988 return (EINVAL); 1989 1990 /* BPF peers is privileged information. */ 1991 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_INTERFACE, 1992 KAUTH_REQ_NETWORK_INTERFACE_GETPRIV, NULL, NULL, NULL); 1993 if (error) 1994 return (EPERM); 1995 1996 len = (oldp != NULL) ? *oldlenp : 0; 1997 sp = oldp; 1998 elem_size = name[0]; 1999 elem_count = name[1]; 2000 out_size = MIN(sizeof(dpe), elem_size); 2001 needed = 0; 2002 2003 if (elem_size < 1 || elem_count < 0) 2004 return (EINVAL); 2005 2006 mutex_enter(&bpf_mtx); 2007 LIST_FOREACH(dp, &bpf_list, bd_list) { 2008 if (len >= elem_size && elem_count > 0) { 2009 #define BPF_EXT(field) dpe.bde_ ## field = dp->bd_ ## field 2010 BPF_EXT(bufsize); 2011 BPF_EXT(promisc); 2012 BPF_EXT(state); 2013 BPF_EXT(immediate); 2014 BPF_EXT(hdrcmplt); 2015 BPF_EXT(seesent); 2016 BPF_EXT(pid); 2017 BPF_EXT(rcount); 2018 BPF_EXT(dcount); 2019 BPF_EXT(ccount); 2020 #undef BPF_EXT 2021 if (dp->bd_bif) 2022 (void)strlcpy(dpe.bde_ifname, 2023 dp->bd_bif->bif_ifp->if_xname, 2024 IFNAMSIZ - 1); 2025 else 2026 dpe.bde_ifname[0] = '\0'; 2027 2028 error = copyout(&dpe, sp, out_size); 2029 if (error) 2030 break; 2031 sp += elem_size; 2032 len -= elem_size; 2033 } 2034 needed += elem_size; 2035 if (elem_count > 0 && elem_count != INT_MAX) 2036 elem_count--; 2037 } 2038 mutex_exit(&bpf_mtx); 2039 2040 *oldlenp = needed; 2041 2042 return (error); 2043 } 2044 2045 static struct sysctllog *bpf_sysctllog; 2046 static void 2047 sysctl_net_bpf_setup(void) 2048 { 2049 const struct sysctlnode *node; 2050 2051 node = NULL; 2052 sysctl_createv(&bpf_sysctllog, 0, NULL, &node, 2053 CTLFLAG_PERMANENT, 2054 CTLTYPE_NODE, "bpf", 2055 SYSCTL_DESCR("BPF options"), 2056 NULL, 0, NULL, 0, 2057 CTL_NET, CTL_CREATE, CTL_EOL); 2058 if (node != NULL) { 2059 #if defined(MODULAR) || defined(BPFJIT) 2060 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2061 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2062 CTLTYPE_BOOL, "jit", 2063 SYSCTL_DESCR("Toggle Just-In-Time compilation"), 2064 sysctl_net_bpf_jit, 0, &bpf_jit, 0, 2065 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2066 #endif 2067 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2068 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2069 CTLTYPE_INT, "maxbufsize", 2070 SYSCTL_DESCR("Maximum size for data capture buffer"), 2071 sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0, 2072 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2073 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2074 CTLFLAG_PERMANENT, 2075 CTLTYPE_STRUCT, "stats", 2076 SYSCTL_DESCR("BPF stats"), 2077 NULL, 0, &bpf_gstats, sizeof(bpf_gstats), 2078 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2079 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2080 CTLFLAG_PERMANENT, 2081 CTLTYPE_STRUCT, "peers", 2082 SYSCTL_DESCR("BPF peers"), 2083 sysctl_net_bpf_peers, 0, NULL, 0, 2084 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2085 } 2086 2087 } 2088 2089 struct bpf_ops bpf_ops_kernel = { 2090 .bpf_attach = _bpfattach, 2091 .bpf_detach = _bpfdetach, 2092 .bpf_change_type = _bpf_change_type, 2093 2094 .bpf_tap = _bpf_tap, 2095 .bpf_mtap = _bpf_mtap, 2096 .bpf_mtap2 = _bpf_mtap2, 2097 .bpf_mtap_af = _bpf_mtap_af, 2098 .bpf_mtap_sl_in = _bpf_mtap_sl_in, 2099 .bpf_mtap_sl_out = _bpf_mtap_sl_out, 2100 }; 2101 2102 MODULE(MODULE_CLASS_DRIVER, bpf, NULL); 2103 2104 static int 2105 bpf_modcmd(modcmd_t cmd, void *arg) 2106 { 2107 devmajor_t bmajor, cmajor; 2108 int error; 2109 2110 bmajor = cmajor = NODEVMAJOR; 2111 2112 switch (cmd) { 2113 case MODULE_CMD_INIT: 2114 bpfilterattach(0); 2115 error = devsw_attach("bpf", NULL, &bmajor, 2116 &bpf_cdevsw, &cmajor); 2117 if (error == EEXIST) 2118 error = 0; /* maybe built-in ... improve eventually */ 2119 if (error) 2120 break; 2121 2122 bpf_ops_handover_enter(&bpf_ops_kernel); 2123 atomic_swap_ptr(&bpf_ops, &bpf_ops_kernel); 2124 bpf_ops_handover_exit(); 2125 sysctl_net_bpf_setup(); 2126 break; 2127 2128 case MODULE_CMD_FINI: 2129 /* 2130 * While there is no reference counting for bpf callers, 2131 * unload could at least in theory be done similarly to 2132 * system call disestablishment. This should even be 2133 * a little simpler: 2134 * 2135 * 1) replace op vector with stubs 2136 * 2) post update to all cpus with xc 2137 * 3) check that nobody is in bpf anymore 2138 * (it's doubtful we'd want something like l_sysent, 2139 * but we could do something like *signed* percpu 2140 * counters. if the sum is 0, we're good). 2141 * 4) if fail, unroll changes 2142 * 2143 * NOTE: change won't be atomic to the outside. some 2144 * packets may be not captured even if unload is 2145 * not succesful. I think packet capture not working 2146 * is a perfectly logical consequence of trying to 2147 * disable packet capture. 2148 */ 2149 error = EOPNOTSUPP; 2150 /* insert sysctl teardown */ 2151 break; 2152 2153 default: 2154 error = ENOTTY; 2155 break; 2156 } 2157 2158 return error; 2159 } 2160