1 /* $NetBSD: bpf.c,v 1.182 2014/03/16 05:20:30 dholland 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 1.182 2014/03/16 05:20:30 dholland 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_flag = D_OTHER 195 }; 196 197 bpfjit_func_t 198 bpf_jit_generate(bpf_ctx_t *bc, void *code, size_t size) 199 { 200 membar_consumer(); 201 if (bpfjit_module_ops.bj_generate_code != NULL) { 202 return bpfjit_module_ops.bj_generate_code(bc, code, size); 203 } 204 return NULL; 205 } 206 207 void 208 bpf_jit_freecode(bpfjit_func_t jcode) 209 { 210 KASSERT(bpfjit_module_ops.bj_free_code != NULL); 211 bpfjit_module_ops.bj_free_code(jcode); 212 } 213 214 static int 215 bpf_movein(struct uio *uio, int linktype, uint64_t mtu, struct mbuf **mp, 216 struct sockaddr *sockp) 217 { 218 struct mbuf *m; 219 int error; 220 size_t len; 221 size_t hlen; 222 size_t align; 223 224 /* 225 * Build a sockaddr based on the data link layer type. 226 * We do this at this level because the ethernet header 227 * is copied directly into the data field of the sockaddr. 228 * In the case of SLIP, there is no header and the packet 229 * is forwarded as is. 230 * Also, we are careful to leave room at the front of the mbuf 231 * for the link level header. 232 */ 233 switch (linktype) { 234 235 case DLT_SLIP: 236 sockp->sa_family = AF_INET; 237 hlen = 0; 238 align = 0; 239 break; 240 241 case DLT_PPP: 242 sockp->sa_family = AF_UNSPEC; 243 hlen = 0; 244 align = 0; 245 break; 246 247 case DLT_EN10MB: 248 sockp->sa_family = AF_UNSPEC; 249 /* XXX Would MAXLINKHDR be better? */ 250 /* 6(dst)+6(src)+2(type) */ 251 hlen = sizeof(struct ether_header); 252 align = 2; 253 break; 254 255 case DLT_ARCNET: 256 sockp->sa_family = AF_UNSPEC; 257 hlen = ARC_HDRLEN; 258 align = 5; 259 break; 260 261 case DLT_FDDI: 262 sockp->sa_family = AF_LINK; 263 /* XXX 4(FORMAC)+6(dst)+6(src) */ 264 hlen = 16; 265 align = 0; 266 break; 267 268 case DLT_ECONET: 269 sockp->sa_family = AF_UNSPEC; 270 hlen = 6; 271 align = 2; 272 break; 273 274 case DLT_NULL: 275 sockp->sa_family = AF_UNSPEC; 276 hlen = 0; 277 align = 0; 278 break; 279 280 default: 281 return (EIO); 282 } 283 284 len = uio->uio_resid; 285 /* 286 * If there aren't enough bytes for a link level header or the 287 * packet length exceeds the interface mtu, return an error. 288 */ 289 if (len - hlen > mtu) 290 return (EMSGSIZE); 291 292 /* 293 * XXX Avoid complicated buffer chaining --- 294 * bail if it won't fit in a single mbuf. 295 * (Take into account possible alignment bytes) 296 */ 297 if (len + align > MCLBYTES) 298 return (EIO); 299 300 m = m_gethdr(M_WAIT, MT_DATA); 301 m->m_pkthdr.rcvif = 0; 302 m->m_pkthdr.len = (int)(len - hlen); 303 if (len + align > MHLEN) { 304 m_clget(m, M_WAIT); 305 if ((m->m_flags & M_EXT) == 0) { 306 error = ENOBUFS; 307 goto bad; 308 } 309 } 310 311 /* Insure the data is properly aligned */ 312 if (align > 0) { 313 m->m_data += align; 314 m->m_len -= (int)align; 315 } 316 317 error = uiomove(mtod(m, void *), len, uio); 318 if (error) 319 goto bad; 320 if (hlen != 0) { 321 memcpy(sockp->sa_data, mtod(m, void *), hlen); 322 m->m_data += hlen; /* XXX */ 323 len -= hlen; 324 } 325 m->m_len = (int)len; 326 *mp = m; 327 return (0); 328 329 bad: 330 m_freem(m); 331 return (error); 332 } 333 334 /* 335 * Attach file to the bpf interface, i.e. make d listen on bp. 336 * Must be called at splnet. 337 */ 338 static void 339 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 340 { 341 /* 342 * Point d at bp, and add d to the interface's list of listeners. 343 * Finally, point the driver's bpf cookie at the interface so 344 * it will divert packets to bpf. 345 */ 346 d->bd_bif = bp; 347 d->bd_next = bp->bif_dlist; 348 bp->bif_dlist = d; 349 350 *bp->bif_driverp = bp; 351 } 352 353 /* 354 * Detach a file from its interface. 355 */ 356 static void 357 bpf_detachd(struct bpf_d *d) 358 { 359 struct bpf_d **p; 360 struct bpf_if *bp; 361 362 bp = d->bd_bif; 363 /* 364 * Check if this descriptor had requested promiscuous mode. 365 * If so, turn it off. 366 */ 367 if (d->bd_promisc) { 368 int error __diagused; 369 370 d->bd_promisc = 0; 371 /* 372 * Take device out of promiscuous mode. Since we were 373 * able to enter promiscuous mode, we should be able 374 * to turn it off. But we can get an error if 375 * the interface was configured down, so only panic 376 * if we don't get an unexpected error. 377 */ 378 error = ifpromisc(bp->bif_ifp, 0); 379 #ifdef DIAGNOSTIC 380 if (error) 381 printf("%s: ifpromisc failed: %d", __func__, error); 382 #endif 383 } 384 /* Remove d from the interface's descriptor list. */ 385 p = &bp->bif_dlist; 386 while (*p != d) { 387 p = &(*p)->bd_next; 388 if (*p == 0) 389 panic("%s: descriptor not in list", __func__); 390 } 391 *p = (*p)->bd_next; 392 if (bp->bif_dlist == 0) 393 /* 394 * Let the driver know that there are no more listeners. 395 */ 396 *d->bd_bif->bif_driverp = 0; 397 d->bd_bif = 0; 398 } 399 400 static int 401 doinit(void) 402 { 403 404 mutex_init(&bpf_mtx, MUTEX_DEFAULT, IPL_NONE); 405 406 LIST_INIT(&bpf_list); 407 408 bpf_gstats.bs_recv = 0; 409 bpf_gstats.bs_drop = 0; 410 bpf_gstats.bs_capt = 0; 411 412 return 0; 413 } 414 415 /* 416 * bpfilterattach() is called at boot time. 417 */ 418 /* ARGSUSED */ 419 void 420 bpfilterattach(int n) 421 { 422 static ONCE_DECL(control); 423 424 RUN_ONCE(&control, doinit); 425 } 426 427 /* 428 * Open ethernet device. Clones. 429 */ 430 /* ARGSUSED */ 431 int 432 bpfopen(dev_t dev, int flag, int mode, struct lwp *l) 433 { 434 struct bpf_d *d; 435 struct file *fp; 436 int error, fd; 437 438 /* falloc() will use the descriptor for us. */ 439 if ((error = fd_allocfile(&fp, &fd)) != 0) 440 return error; 441 442 d = malloc(sizeof(*d), M_DEVBUF, M_WAITOK|M_ZERO); 443 d->bd_bufsize = bpf_bufsize; 444 d->bd_seesent = 1; 445 d->bd_feedback = 0; 446 d->bd_pid = l->l_proc->p_pid; 447 #ifdef _LP64 448 if (curproc->p_flag & PK_32) 449 d->bd_compat32 = 1; 450 #endif 451 getnanotime(&d->bd_btime); 452 d->bd_atime = d->bd_mtime = d->bd_btime; 453 callout_init(&d->bd_callout, 0); 454 selinit(&d->bd_sel); 455 d->bd_sih = softint_establish(SOFTINT_CLOCK, bpf_softintr, d); 456 d->bd_jitcode = NULL; 457 458 mutex_enter(&bpf_mtx); 459 LIST_INSERT_HEAD(&bpf_list, d, bd_list); 460 mutex_exit(&bpf_mtx); 461 462 return fd_clone(fp, fd, flag, &bpf_fileops, d); 463 } 464 465 /* 466 * Close the descriptor by detaching it from its interface, 467 * deallocating its buffers, and marking it free. 468 */ 469 /* ARGSUSED */ 470 static int 471 bpf_close(struct file *fp) 472 { 473 struct bpf_d *d = fp->f_data; 474 int s; 475 476 KERNEL_LOCK(1, NULL); 477 478 /* 479 * Refresh the PID associated with this bpf file. 480 */ 481 d->bd_pid = curproc->p_pid; 482 483 s = splnet(); 484 if (d->bd_state == BPF_WAITING) 485 callout_stop(&d->bd_callout); 486 d->bd_state = BPF_IDLE; 487 if (d->bd_bif) 488 bpf_detachd(d); 489 splx(s); 490 bpf_freed(d); 491 mutex_enter(&bpf_mtx); 492 LIST_REMOVE(d, bd_list); 493 mutex_exit(&bpf_mtx); 494 callout_destroy(&d->bd_callout); 495 seldestroy(&d->bd_sel); 496 softint_disestablish(d->bd_sih); 497 free(d, M_DEVBUF); 498 fp->f_data = NULL; 499 500 KERNEL_UNLOCK_ONE(NULL); 501 502 return (0); 503 } 504 505 /* 506 * Rotate the packet buffers in descriptor d. Move the store buffer 507 * into the hold slot, and the free buffer into the store slot. 508 * Zero the length of the new store buffer. 509 */ 510 #define ROTATE_BUFFERS(d) \ 511 (d)->bd_hbuf = (d)->bd_sbuf; \ 512 (d)->bd_hlen = (d)->bd_slen; \ 513 (d)->bd_sbuf = (d)->bd_fbuf; \ 514 (d)->bd_slen = 0; \ 515 (d)->bd_fbuf = 0; 516 /* 517 * bpfread - read next chunk of packets from buffers 518 */ 519 static int 520 bpf_read(struct file *fp, off_t *offp, struct uio *uio, 521 kauth_cred_t cred, int flags) 522 { 523 struct bpf_d *d = fp->f_data; 524 int timed_out; 525 int error; 526 int s; 527 528 getnanotime(&d->bd_atime); 529 /* 530 * Restrict application to use a buffer the same size as 531 * the kernel buffers. 532 */ 533 if (uio->uio_resid != d->bd_bufsize) 534 return (EINVAL); 535 536 KERNEL_LOCK(1, NULL); 537 s = splnet(); 538 if (d->bd_state == BPF_WAITING) 539 callout_stop(&d->bd_callout); 540 timed_out = (d->bd_state == BPF_TIMED_OUT); 541 d->bd_state = BPF_IDLE; 542 /* 543 * If the hold buffer is empty, then do a timed sleep, which 544 * ends when the timeout expires or when enough packets 545 * have arrived to fill the store buffer. 546 */ 547 while (d->bd_hbuf == 0) { 548 if (fp->f_flag & FNONBLOCK) { 549 if (d->bd_slen == 0) { 550 splx(s); 551 KERNEL_UNLOCK_ONE(NULL); 552 return (EWOULDBLOCK); 553 } 554 ROTATE_BUFFERS(d); 555 break; 556 } 557 558 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 559 /* 560 * A packet(s) either arrived since the previous 561 * read or arrived while we were asleep. 562 * Rotate the buffers and return what's here. 563 */ 564 ROTATE_BUFFERS(d); 565 break; 566 } 567 error = tsleep(d, PRINET|PCATCH, "bpf", 568 d->bd_rtout); 569 if (error == EINTR || error == ERESTART) { 570 splx(s); 571 KERNEL_UNLOCK_ONE(NULL); 572 return (error); 573 } 574 if (error == EWOULDBLOCK) { 575 /* 576 * On a timeout, return what's in the buffer, 577 * which may be nothing. If there is something 578 * in the store buffer, we can rotate the buffers. 579 */ 580 if (d->bd_hbuf) 581 /* 582 * We filled up the buffer in between 583 * getting the timeout and arriving 584 * here, so we don't need to rotate. 585 */ 586 break; 587 588 if (d->bd_slen == 0) { 589 splx(s); 590 KERNEL_UNLOCK_ONE(NULL); 591 return (0); 592 } 593 ROTATE_BUFFERS(d); 594 break; 595 } 596 if (error != 0) 597 goto done; 598 } 599 /* 600 * At this point, we know we have something in the hold slot. 601 */ 602 splx(s); 603 604 /* 605 * Move data from hold buffer into user space. 606 * We know the entire buffer is transferred since 607 * we checked above that the read buffer is bpf_bufsize bytes. 608 */ 609 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 610 611 s = splnet(); 612 d->bd_fbuf = d->bd_hbuf; 613 d->bd_hbuf = 0; 614 d->bd_hlen = 0; 615 done: 616 splx(s); 617 KERNEL_UNLOCK_ONE(NULL); 618 return (error); 619 } 620 621 622 /* 623 * If there are processes sleeping on this descriptor, wake them up. 624 */ 625 static inline void 626 bpf_wakeup(struct bpf_d *d) 627 { 628 wakeup(d); 629 if (d->bd_async) 630 softint_schedule(d->bd_sih); 631 selnotify(&d->bd_sel, 0, 0); 632 } 633 634 static void 635 bpf_softintr(void *cookie) 636 { 637 struct bpf_d *d; 638 639 d = cookie; 640 if (d->bd_async) 641 fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL); 642 } 643 644 static void 645 bpf_timed_out(void *arg) 646 { 647 struct bpf_d *d = arg; 648 int s; 649 650 s = splnet(); 651 if (d->bd_state == BPF_WAITING) { 652 d->bd_state = BPF_TIMED_OUT; 653 if (d->bd_slen != 0) 654 bpf_wakeup(d); 655 } 656 splx(s); 657 } 658 659 660 static int 661 bpf_write(struct file *fp, off_t *offp, struct uio *uio, 662 kauth_cred_t cred, int flags) 663 { 664 struct bpf_d *d = fp->f_data; 665 struct ifnet *ifp; 666 struct mbuf *m, *mc; 667 int error, s; 668 static struct sockaddr_storage dst; 669 670 m = NULL; /* XXX gcc */ 671 672 KERNEL_LOCK(1, NULL); 673 674 if (d->bd_bif == 0) { 675 KERNEL_UNLOCK_ONE(NULL); 676 return (ENXIO); 677 } 678 getnanotime(&d->bd_mtime); 679 680 ifp = d->bd_bif->bif_ifp; 681 682 if (uio->uio_resid == 0) { 683 KERNEL_UNLOCK_ONE(NULL); 684 return (0); 685 } 686 687 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, &m, 688 (struct sockaddr *) &dst); 689 if (error) { 690 KERNEL_UNLOCK_ONE(NULL); 691 return (error); 692 } 693 694 if (m->m_pkthdr.len > ifp->if_mtu) { 695 KERNEL_UNLOCK_ONE(NULL); 696 m_freem(m); 697 return (EMSGSIZE); 698 } 699 700 if (d->bd_hdrcmplt) 701 dst.ss_family = pseudo_AF_HDRCMPLT; 702 703 if (d->bd_feedback) { 704 mc = m_dup(m, 0, M_COPYALL, M_NOWAIT); 705 if (mc != NULL) 706 mc->m_pkthdr.rcvif = ifp; 707 /* Set M_PROMISC for outgoing packets to be discarded. */ 708 if (1 /*d->bd_direction == BPF_D_INOUT*/) 709 m->m_flags |= M_PROMISC; 710 } else 711 mc = NULL; 712 713 s = splsoftnet(); 714 error = (*ifp->if_output)(ifp, m, (struct sockaddr *) &dst, NULL); 715 716 if (mc != NULL) { 717 if (error == 0) 718 (*ifp->if_input)(ifp, mc); 719 m_freem(mc); 720 } 721 splx(s); 722 KERNEL_UNLOCK_ONE(NULL); 723 /* 724 * The driver frees the mbuf. 725 */ 726 return (error); 727 } 728 729 /* 730 * Reset a descriptor by flushing its packet buffer and clearing the 731 * receive and drop counts. Should be called at splnet. 732 */ 733 static void 734 reset_d(struct bpf_d *d) 735 { 736 if (d->bd_hbuf) { 737 /* Free the hold buffer. */ 738 d->bd_fbuf = d->bd_hbuf; 739 d->bd_hbuf = 0; 740 } 741 d->bd_slen = 0; 742 d->bd_hlen = 0; 743 d->bd_rcount = 0; 744 d->bd_dcount = 0; 745 d->bd_ccount = 0; 746 } 747 748 /* 749 * FIONREAD Check for read packet available. 750 * BIOCGBLEN Get buffer len [for read()]. 751 * BIOCSETF Set ethernet read filter. 752 * BIOCFLUSH Flush read packet buffer. 753 * BIOCPROMISC Put interface into promiscuous mode. 754 * BIOCGDLT Get link layer type. 755 * BIOCGETIF Get interface name. 756 * BIOCSETIF Set interface. 757 * BIOCSRTIMEOUT Set read timeout. 758 * BIOCGRTIMEOUT Get read timeout. 759 * BIOCGSTATS Get packet stats. 760 * BIOCIMMEDIATE Set immediate mode. 761 * BIOCVERSION Get filter language version. 762 * BIOCGHDRCMPLT Get "header already complete" flag. 763 * BIOCSHDRCMPLT Set "header already complete" flag. 764 * BIOCSFEEDBACK Set packet feedback mode. 765 * BIOCGFEEDBACK Get packet feedback mode. 766 * BIOCGSEESENT Get "see sent packets" mode. 767 * BIOCSSEESENT Set "see sent packets" mode. 768 */ 769 /* ARGSUSED */ 770 static int 771 bpf_ioctl(struct file *fp, u_long cmd, void *addr) 772 { 773 struct bpf_d *d = fp->f_data; 774 int s, error = 0; 775 776 /* 777 * Refresh the PID associated with this bpf file. 778 */ 779 KERNEL_LOCK(1, NULL); 780 d->bd_pid = curproc->p_pid; 781 #ifdef _LP64 782 if (curproc->p_flag & PK_32) 783 d->bd_compat32 = 1; 784 else 785 d->bd_compat32 = 0; 786 #endif 787 788 s = splnet(); 789 if (d->bd_state == BPF_WAITING) 790 callout_stop(&d->bd_callout); 791 d->bd_state = BPF_IDLE; 792 splx(s); 793 794 switch (cmd) { 795 796 default: 797 error = EINVAL; 798 break; 799 800 /* 801 * Check for read packet available. 802 */ 803 case FIONREAD: 804 { 805 int n; 806 807 s = splnet(); 808 n = d->bd_slen; 809 if (d->bd_hbuf) 810 n += d->bd_hlen; 811 splx(s); 812 813 *(int *)addr = n; 814 break; 815 } 816 817 /* 818 * Get buffer len [for read()]. 819 */ 820 case BIOCGBLEN: 821 *(u_int *)addr = d->bd_bufsize; 822 break; 823 824 /* 825 * Set buffer length. 826 */ 827 case BIOCSBLEN: 828 if (d->bd_bif != 0) 829 error = EINVAL; 830 else { 831 u_int size = *(u_int *)addr; 832 833 if (size > bpf_maxbufsize) 834 *(u_int *)addr = size = bpf_maxbufsize; 835 else if (size < BPF_MINBUFSIZE) 836 *(u_int *)addr = size = BPF_MINBUFSIZE; 837 d->bd_bufsize = size; 838 } 839 break; 840 841 /* 842 * Set link layer read filter. 843 */ 844 case BIOCSETF: 845 error = bpf_setf(d, addr); 846 break; 847 848 /* 849 * Flush read packet buffer. 850 */ 851 case BIOCFLUSH: 852 s = splnet(); 853 reset_d(d); 854 splx(s); 855 break; 856 857 /* 858 * Put interface into promiscuous mode. 859 */ 860 case BIOCPROMISC: 861 if (d->bd_bif == 0) { 862 /* 863 * No interface attached yet. 864 */ 865 error = EINVAL; 866 break; 867 } 868 s = splnet(); 869 if (d->bd_promisc == 0) { 870 error = ifpromisc(d->bd_bif->bif_ifp, 1); 871 if (error == 0) 872 d->bd_promisc = 1; 873 } 874 splx(s); 875 break; 876 877 /* 878 * Get device parameters. 879 */ 880 case BIOCGDLT: 881 if (d->bd_bif == 0) 882 error = EINVAL; 883 else 884 *(u_int *)addr = d->bd_bif->bif_dlt; 885 break; 886 887 /* 888 * Get a list of supported device parameters. 889 */ 890 case BIOCGDLTLIST: 891 if (d->bd_bif == 0) 892 error = EINVAL; 893 else 894 error = bpf_getdltlist(d, addr); 895 break; 896 897 /* 898 * Set device parameters. 899 */ 900 case BIOCSDLT: 901 if (d->bd_bif == 0) 902 error = EINVAL; 903 else 904 error = bpf_setdlt(d, *(u_int *)addr); 905 break; 906 907 /* 908 * Set interface name. 909 */ 910 #ifdef OBIOCGETIF 911 case OBIOCGETIF: 912 #endif 913 case BIOCGETIF: 914 if (d->bd_bif == 0) 915 error = EINVAL; 916 else 917 bpf_ifname(d->bd_bif->bif_ifp, addr); 918 break; 919 920 /* 921 * Set interface. 922 */ 923 #ifdef OBIOCSETIF 924 case OBIOCSETIF: 925 #endif 926 case BIOCSETIF: 927 error = bpf_setif(d, addr); 928 break; 929 930 /* 931 * Set read timeout. 932 */ 933 case BIOCSRTIMEOUT: 934 { 935 struct timeval *tv = addr; 936 937 /* Compute number of ticks. */ 938 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 939 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 940 d->bd_rtout = 1; 941 break; 942 } 943 944 #ifdef BIOCGORTIMEOUT 945 /* 946 * Get read timeout. 947 */ 948 case BIOCGORTIMEOUT: 949 { 950 struct timeval50 *tv = addr; 951 952 tv->tv_sec = d->bd_rtout / hz; 953 tv->tv_usec = (d->bd_rtout % hz) * tick; 954 break; 955 } 956 #endif 957 958 #ifdef BIOCSORTIMEOUT 959 /* 960 * Set read timeout. 961 */ 962 case BIOCSORTIMEOUT: 963 { 964 struct timeval50 *tv = addr; 965 966 /* Compute number of ticks. */ 967 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 968 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 969 d->bd_rtout = 1; 970 break; 971 } 972 #endif 973 974 /* 975 * Get read timeout. 976 */ 977 case BIOCGRTIMEOUT: 978 { 979 struct timeval *tv = addr; 980 981 tv->tv_sec = d->bd_rtout / hz; 982 tv->tv_usec = (d->bd_rtout % hz) * tick; 983 break; 984 } 985 /* 986 * Get packet stats. 987 */ 988 case BIOCGSTATS: 989 { 990 struct bpf_stat *bs = addr; 991 992 bs->bs_recv = d->bd_rcount; 993 bs->bs_drop = d->bd_dcount; 994 bs->bs_capt = d->bd_ccount; 995 break; 996 } 997 998 case BIOCGSTATSOLD: 999 { 1000 struct bpf_stat_old *bs = addr; 1001 1002 bs->bs_recv = d->bd_rcount; 1003 bs->bs_drop = d->bd_dcount; 1004 break; 1005 } 1006 1007 /* 1008 * Set immediate mode. 1009 */ 1010 case BIOCIMMEDIATE: 1011 d->bd_immediate = *(u_int *)addr; 1012 break; 1013 1014 case BIOCVERSION: 1015 { 1016 struct bpf_version *bv = addr; 1017 1018 bv->bv_major = BPF_MAJOR_VERSION; 1019 bv->bv_minor = BPF_MINOR_VERSION; 1020 break; 1021 } 1022 1023 case BIOCGHDRCMPLT: /* get "header already complete" flag */ 1024 *(u_int *)addr = d->bd_hdrcmplt; 1025 break; 1026 1027 case BIOCSHDRCMPLT: /* set "header already complete" flag */ 1028 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 1029 break; 1030 1031 /* 1032 * Get "see sent packets" flag 1033 */ 1034 case BIOCGSEESENT: 1035 *(u_int *)addr = d->bd_seesent; 1036 break; 1037 1038 /* 1039 * Set "see sent" packets flag 1040 */ 1041 case BIOCSSEESENT: 1042 d->bd_seesent = *(u_int *)addr; 1043 break; 1044 1045 /* 1046 * Set "feed packets from bpf back to input" mode 1047 */ 1048 case BIOCSFEEDBACK: 1049 d->bd_feedback = *(u_int *)addr; 1050 break; 1051 1052 /* 1053 * Get "feed packets from bpf back to input" mode 1054 */ 1055 case BIOCGFEEDBACK: 1056 *(u_int *)addr = d->bd_feedback; 1057 break; 1058 1059 case FIONBIO: /* Non-blocking I/O */ 1060 /* 1061 * No need to do anything special as we use IO_NDELAY in 1062 * bpfread() as an indication of whether or not to block 1063 * the read. 1064 */ 1065 break; 1066 1067 case FIOASYNC: /* Send signal on receive packets */ 1068 d->bd_async = *(int *)addr; 1069 break; 1070 1071 case TIOCSPGRP: /* Process or group to send signals to */ 1072 case FIOSETOWN: 1073 error = fsetown(&d->bd_pgid, cmd, addr); 1074 break; 1075 1076 case TIOCGPGRP: 1077 case FIOGETOWN: 1078 error = fgetown(d->bd_pgid, cmd, addr); 1079 break; 1080 } 1081 KERNEL_UNLOCK_ONE(NULL); 1082 return (error); 1083 } 1084 1085 /* 1086 * Set d's packet filter program to fp. If this file already has a filter, 1087 * free it and replace it. Returns EINVAL for bogus requests. 1088 */ 1089 int 1090 bpf_setf(struct bpf_d *d, struct bpf_program *fp) 1091 { 1092 struct bpf_insn *fcode, *old; 1093 bpfjit_func_t jcode, oldj; 1094 size_t flen, size; 1095 int s; 1096 1097 jcode = NULL; 1098 flen = fp->bf_len; 1099 1100 if ((fp->bf_insns == NULL && flen) || flen > BPF_MAXINSNS) { 1101 return EINVAL; 1102 } 1103 1104 if (flen) { 1105 /* 1106 * Allocate the buffer, copy the byte-code from 1107 * userspace and validate it. 1108 */ 1109 size = flen * sizeof(*fp->bf_insns); 1110 fcode = malloc(size, M_DEVBUF, M_WAITOK); 1111 if (copyin(fp->bf_insns, fcode, size) != 0 || 1112 !bpf_validate(fcode, (int)flen)) { 1113 free(fcode, M_DEVBUF); 1114 return EINVAL; 1115 } 1116 membar_consumer(); 1117 if (bpf_jit) { 1118 bpf_ctx_t *bc = bpf_default_ctx(); 1119 jcode = bpf_jit_generate(bc, fcode, flen); 1120 } 1121 } else { 1122 fcode = NULL; 1123 } 1124 1125 s = splnet(); 1126 old = d->bd_filter; 1127 d->bd_filter = fcode; 1128 oldj = d->bd_jitcode; 1129 d->bd_jitcode = jcode; 1130 reset_d(d); 1131 splx(s); 1132 1133 if (old) { 1134 free(old, M_DEVBUF); 1135 } 1136 if (oldj) { 1137 bpf_jit_freecode(oldj); 1138 } 1139 1140 return 0; 1141 } 1142 1143 /* 1144 * Detach a file from its current interface (if attached at all) and attach 1145 * to the interface indicated by the name stored in ifr. 1146 * Return an errno or 0. 1147 */ 1148 static int 1149 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 1150 { 1151 struct bpf_if *bp; 1152 char *cp; 1153 int unit_seen, i, s, error; 1154 1155 /* 1156 * Make sure the provided name has a unit number, and default 1157 * it to '0' if not specified. 1158 * XXX This is ugly ... do this differently? 1159 */ 1160 unit_seen = 0; 1161 cp = ifr->ifr_name; 1162 cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */ 1163 while (*cp++) 1164 if (*cp >= '0' && *cp <= '9') 1165 unit_seen = 1; 1166 if (!unit_seen) { 1167 /* Make sure to leave room for the '\0'. */ 1168 for (i = 0; i < (IFNAMSIZ - 1); ++i) { 1169 if ((ifr->ifr_name[i] >= 'a' && 1170 ifr->ifr_name[i] <= 'z') || 1171 (ifr->ifr_name[i] >= 'A' && 1172 ifr->ifr_name[i] <= 'Z')) 1173 continue; 1174 ifr->ifr_name[i] = '0'; 1175 } 1176 } 1177 1178 /* 1179 * Look through attached interfaces for the named one. 1180 */ 1181 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 1182 struct ifnet *ifp = bp->bif_ifp; 1183 1184 if (ifp == 0 || 1185 strcmp(ifp->if_xname, ifr->ifr_name) != 0) 1186 continue; 1187 /* skip additional entry */ 1188 if (bp->bif_driverp != &ifp->if_bpf) 1189 continue; 1190 /* 1191 * We found the requested interface. 1192 * Allocate the packet buffers if we need to. 1193 * If we're already attached to requested interface, 1194 * just flush the buffer. 1195 */ 1196 if (d->bd_sbuf == 0) { 1197 error = bpf_allocbufs(d); 1198 if (error != 0) 1199 return (error); 1200 } 1201 s = splnet(); 1202 if (bp != d->bd_bif) { 1203 if (d->bd_bif) 1204 /* 1205 * Detach if attached to something else. 1206 */ 1207 bpf_detachd(d); 1208 1209 bpf_attachd(d, bp); 1210 } 1211 reset_d(d); 1212 splx(s); 1213 return (0); 1214 } 1215 /* Not found. */ 1216 return (ENXIO); 1217 } 1218 1219 /* 1220 * Copy the interface name to the ifreq. 1221 */ 1222 static void 1223 bpf_ifname(struct ifnet *ifp, struct ifreq *ifr) 1224 { 1225 memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1226 } 1227 1228 static int 1229 bpf_stat(struct file *fp, struct stat *st) 1230 { 1231 struct bpf_d *d = fp->f_data; 1232 1233 (void)memset(st, 0, sizeof(*st)); 1234 KERNEL_LOCK(1, NULL); 1235 st->st_dev = makedev(cdevsw_lookup_major(&bpf_cdevsw), d->bd_pid); 1236 st->st_atimespec = d->bd_atime; 1237 st->st_mtimespec = d->bd_mtime; 1238 st->st_ctimespec = st->st_birthtimespec = d->bd_btime; 1239 st->st_uid = kauth_cred_geteuid(fp->f_cred); 1240 st->st_gid = kauth_cred_getegid(fp->f_cred); 1241 st->st_mode = S_IFCHR; 1242 KERNEL_UNLOCK_ONE(NULL); 1243 return 0; 1244 } 1245 1246 /* 1247 * Support for poll() system call 1248 * 1249 * Return true iff the specific operation will not block indefinitely - with 1250 * the assumption that it is safe to positively acknowledge a request for the 1251 * ability to write to the BPF device. 1252 * Otherwise, return false but make a note that a selnotify() must be done. 1253 */ 1254 static int 1255 bpf_poll(struct file *fp, int events) 1256 { 1257 struct bpf_d *d = fp->f_data; 1258 int s = splnet(); 1259 int revents; 1260 1261 /* 1262 * Refresh the PID associated with this bpf file. 1263 */ 1264 KERNEL_LOCK(1, NULL); 1265 d->bd_pid = curproc->p_pid; 1266 1267 revents = events & (POLLOUT | POLLWRNORM); 1268 if (events & (POLLIN | POLLRDNORM)) { 1269 /* 1270 * An imitation of the FIONREAD ioctl code. 1271 */ 1272 if (d->bd_hlen != 0 || 1273 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) && 1274 d->bd_slen != 0)) { 1275 revents |= events & (POLLIN | POLLRDNORM); 1276 } else { 1277 selrecord(curlwp, &d->bd_sel); 1278 /* Start the read timeout if necessary */ 1279 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1280 callout_reset(&d->bd_callout, d->bd_rtout, 1281 bpf_timed_out, d); 1282 d->bd_state = BPF_WAITING; 1283 } 1284 } 1285 } 1286 1287 KERNEL_UNLOCK_ONE(NULL); 1288 splx(s); 1289 return (revents); 1290 } 1291 1292 static void 1293 filt_bpfrdetach(struct knote *kn) 1294 { 1295 struct bpf_d *d = kn->kn_hook; 1296 int s; 1297 1298 KERNEL_LOCK(1, NULL); 1299 s = splnet(); 1300 SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext); 1301 splx(s); 1302 KERNEL_UNLOCK_ONE(NULL); 1303 } 1304 1305 static int 1306 filt_bpfread(struct knote *kn, long hint) 1307 { 1308 struct bpf_d *d = kn->kn_hook; 1309 int rv; 1310 1311 KERNEL_LOCK(1, NULL); 1312 kn->kn_data = d->bd_hlen; 1313 if (d->bd_immediate) 1314 kn->kn_data += d->bd_slen; 1315 rv = (kn->kn_data > 0); 1316 KERNEL_UNLOCK_ONE(NULL); 1317 return rv; 1318 } 1319 1320 static const struct filterops bpfread_filtops = 1321 { 1, NULL, filt_bpfrdetach, filt_bpfread }; 1322 1323 static int 1324 bpf_kqfilter(struct file *fp, struct knote *kn) 1325 { 1326 struct bpf_d *d = fp->f_data; 1327 struct klist *klist; 1328 int s; 1329 1330 KERNEL_LOCK(1, NULL); 1331 1332 switch (kn->kn_filter) { 1333 case EVFILT_READ: 1334 klist = &d->bd_sel.sel_klist; 1335 kn->kn_fop = &bpfread_filtops; 1336 break; 1337 1338 default: 1339 KERNEL_UNLOCK_ONE(NULL); 1340 return (EINVAL); 1341 } 1342 1343 kn->kn_hook = d; 1344 1345 s = splnet(); 1346 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 1347 splx(s); 1348 KERNEL_UNLOCK_ONE(NULL); 1349 1350 return (0); 1351 } 1352 1353 /* 1354 * Copy data from an mbuf chain into a buffer. This code is derived 1355 * from m_copydata in sys/uipc_mbuf.c. 1356 */ 1357 static void * 1358 bpf_mcpy(void *dst_arg, const void *src_arg, size_t len) 1359 { 1360 const struct mbuf *m; 1361 u_int count; 1362 u_char *dst; 1363 1364 m = src_arg; 1365 dst = dst_arg; 1366 while (len > 0) { 1367 if (m == NULL) 1368 panic("bpf_mcpy"); 1369 count = min(m->m_len, len); 1370 memcpy(dst, mtod(m, const void *), count); 1371 m = m->m_next; 1372 dst += count; 1373 len -= count; 1374 } 1375 return dst_arg; 1376 } 1377 1378 /* 1379 * Dispatch a packet to all the listeners on interface bp. 1380 * 1381 * pkt pointer to the packet, either a data buffer or an mbuf chain 1382 * buflen buffer length, if pkt is a data buffer 1383 * cpfn a function that can copy pkt into the listener's buffer 1384 * pktlen length of the packet 1385 * rcv true if packet came in 1386 */ 1387 static inline void 1388 bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t), 1389 void *pkt, u_int pktlen, u_int buflen, const bool rcv) 1390 { 1391 bpf_ctx_t *bc = bpf_default_ctx(); 1392 bpf_args_t args = { 1393 .pkt = pkt, 1394 .wirelen = pktlen, 1395 .buflen = buflen, 1396 .arg = NULL 1397 }; 1398 struct bpf_d *d; 1399 struct timespec ts; 1400 bool gottime = false; 1401 1402 /* 1403 * Note that the IPL does not have to be raised at this point. 1404 * The only problem that could arise here is that if two different 1405 * interfaces shared any data. This is not the case. 1406 */ 1407 for (d = bp->bif_dlist; d != NULL; d = d->bd_next) { 1408 u_int slen; 1409 1410 if (!d->bd_seesent && !rcv) { 1411 continue; 1412 } 1413 d->bd_rcount++; 1414 bpf_gstats.bs_recv++; 1415 1416 if (d->bd_jitcode) 1417 slen = d->bd_jitcode(pkt, pktlen, buflen); 1418 else 1419 slen = bpf_filter_ext(bc, d->bd_filter, &args); 1420 1421 if (!slen) { 1422 continue; 1423 } 1424 if (!gottime) { 1425 gottime = true; 1426 nanotime(&ts); 1427 } 1428 catchpacket(d, pkt, pktlen, slen, cpfn, &ts); 1429 } 1430 } 1431 1432 /* 1433 * Incoming linkage from device drivers. Process the packet pkt, of length 1434 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1435 * by each process' filter, and if accepted, stashed into the corresponding 1436 * buffer. 1437 */ 1438 static void 1439 _bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1440 { 1441 1442 bpf_deliver(bp, memcpy, pkt, pktlen, pktlen, true); 1443 } 1444 1445 /* 1446 * Incoming linkage from device drivers, when the head of the packet is in 1447 * a buffer, and the tail is in an mbuf chain. 1448 */ 1449 static void 1450 _bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) 1451 { 1452 u_int pktlen; 1453 struct mbuf mb; 1454 1455 /* Skip outgoing duplicate packets. */ 1456 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) { 1457 m->m_flags &= ~M_PROMISC; 1458 return; 1459 } 1460 1461 pktlen = m_length(m) + dlen; 1462 1463 /* 1464 * Craft on-stack mbuf suitable for passing to bpf_filter. 1465 * Note that we cut corners here; we only setup what's 1466 * absolutely needed--this mbuf should never go anywhere else. 1467 */ 1468 (void)memset(&mb, 0, sizeof(mb)); 1469 mb.m_next = m; 1470 mb.m_data = data; 1471 mb.m_len = dlen; 1472 1473 bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif != NULL); 1474 } 1475 1476 /* 1477 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1478 */ 1479 static void 1480 _bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1481 { 1482 void *(*cpfn)(void *, const void *, size_t); 1483 u_int pktlen, buflen; 1484 void *marg; 1485 1486 /* Skip outgoing duplicate packets. */ 1487 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif == NULL) { 1488 m->m_flags &= ~M_PROMISC; 1489 return; 1490 } 1491 1492 pktlen = m_length(m); 1493 1494 if (pktlen == m->m_len) { 1495 cpfn = (void *)memcpy; 1496 marg = mtod(m, void *); 1497 buflen = pktlen; 1498 } else { 1499 cpfn = bpf_mcpy; 1500 marg = m; 1501 buflen = 0; 1502 } 1503 1504 bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif != NULL); 1505 } 1506 1507 /* 1508 * We need to prepend the address family as 1509 * a four byte field. Cons up a dummy header 1510 * to pacify bpf. This is safe because bpf 1511 * will only read from the mbuf (i.e., it won't 1512 * try to free it or keep a pointer a to it). 1513 */ 1514 static void 1515 _bpf_mtap_af(struct bpf_if *bp, uint32_t af, struct mbuf *m) 1516 { 1517 struct mbuf m0; 1518 1519 m0.m_flags = 0; 1520 m0.m_next = m; 1521 m0.m_len = 4; 1522 m0.m_data = (char *)⁡ 1523 1524 _bpf_mtap(bp, &m0); 1525 } 1526 1527 /* 1528 * Put the SLIP pseudo-"link header" in place. 1529 * Note this M_PREPEND() should never fail, 1530 * swince we know we always have enough space 1531 * in the input buffer. 1532 */ 1533 static void 1534 _bpf_mtap_sl_in(struct bpf_if *bp, u_char *chdr, struct mbuf **m) 1535 { 1536 int s; 1537 u_char *hp; 1538 1539 M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT); 1540 if (*m == NULL) 1541 return; 1542 1543 hp = mtod(*m, u_char *); 1544 hp[SLX_DIR] = SLIPDIR_IN; 1545 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1546 1547 s = splnet(); 1548 _bpf_mtap(bp, *m); 1549 splx(s); 1550 1551 m_adj(*m, SLIP_HDRLEN); 1552 } 1553 1554 /* 1555 * Put the SLIP pseudo-"link header" in 1556 * place. The compressed header is now 1557 * at the beginning of the mbuf. 1558 */ 1559 static void 1560 _bpf_mtap_sl_out(struct bpf_if *bp, u_char *chdr, struct mbuf *m) 1561 { 1562 struct mbuf m0; 1563 u_char *hp; 1564 int s; 1565 1566 m0.m_flags = 0; 1567 m0.m_next = m; 1568 m0.m_data = m0.m_dat; 1569 m0.m_len = SLIP_HDRLEN; 1570 1571 hp = mtod(&m0, u_char *); 1572 1573 hp[SLX_DIR] = SLIPDIR_OUT; 1574 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1575 1576 s = splnet(); 1577 _bpf_mtap(bp, &m0); 1578 splx(s); 1579 m_freem(m); 1580 } 1581 1582 static int 1583 bpf_hdrlen(struct bpf_d *d) 1584 { 1585 int hdrlen = d->bd_bif->bif_hdrlen; 1586 /* 1587 * Compute the length of the bpf header. This is not necessarily 1588 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1589 * that the network layer header begins on a longword boundary (for 1590 * performance reasons and to alleviate alignment restrictions). 1591 */ 1592 #ifdef _LP64 1593 if (d->bd_compat32) 1594 return (BPF_WORDALIGN32(hdrlen + SIZEOF_BPF_HDR32) - hdrlen); 1595 else 1596 #endif 1597 return (BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen); 1598 } 1599 1600 /* 1601 * Move the packet data from interface memory (pkt) into the 1602 * store buffer. Call the wakeup functions if it's time to wakeup 1603 * a listener (buffer full), "cpfn" is the routine called to do the 1604 * actual data transfer. memcpy is passed in to copy contiguous chunks, 1605 * while bpf_mcpy is passed in to copy mbuf chains. In the latter case, 1606 * pkt is really an mbuf. 1607 */ 1608 static void 1609 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1610 void *(*cpfn)(void *, const void *, size_t), struct timespec *ts) 1611 { 1612 char *h; 1613 int totlen, curlen, caplen; 1614 int hdrlen = bpf_hdrlen(d); 1615 int do_wakeup = 0; 1616 1617 ++d->bd_ccount; 1618 ++bpf_gstats.bs_capt; 1619 /* 1620 * Figure out how many bytes to move. If the packet is 1621 * greater or equal to the snapshot length, transfer that 1622 * much. Otherwise, transfer the whole packet (unless 1623 * we hit the buffer size limit). 1624 */ 1625 totlen = hdrlen + min(snaplen, pktlen); 1626 if (totlen > d->bd_bufsize) 1627 totlen = d->bd_bufsize; 1628 /* 1629 * If we adjusted totlen to fit the bufsize, it could be that 1630 * totlen is smaller than hdrlen because of the link layer header. 1631 */ 1632 caplen = totlen - hdrlen; 1633 if (caplen < 0) 1634 caplen = 0; 1635 1636 /* 1637 * Round up the end of the previous packet to the next longword. 1638 */ 1639 #ifdef _LP64 1640 if (d->bd_compat32) 1641 curlen = BPF_WORDALIGN32(d->bd_slen); 1642 else 1643 #endif 1644 curlen = BPF_WORDALIGN(d->bd_slen); 1645 if (curlen + totlen > d->bd_bufsize) { 1646 /* 1647 * This packet will overflow the storage buffer. 1648 * Rotate the buffers if we can, then wakeup any 1649 * pending reads. 1650 */ 1651 if (d->bd_fbuf == 0) { 1652 /* 1653 * We haven't completed the previous read yet, 1654 * so drop the packet. 1655 */ 1656 ++d->bd_dcount; 1657 ++bpf_gstats.bs_drop; 1658 return; 1659 } 1660 ROTATE_BUFFERS(d); 1661 do_wakeup = 1; 1662 curlen = 0; 1663 } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) { 1664 /* 1665 * Immediate mode is set, or the read timeout has 1666 * already expired during a select call. A packet 1667 * arrived, so the reader should be woken up. 1668 */ 1669 do_wakeup = 1; 1670 } 1671 1672 /* 1673 * Append the bpf header. 1674 */ 1675 h = (char *)d->bd_sbuf + curlen; 1676 #ifdef _LP64 1677 if (d->bd_compat32) { 1678 struct bpf_hdr32 *hp32; 1679 1680 hp32 = (struct bpf_hdr32 *)h; 1681 hp32->bh_tstamp.tv_sec = ts->tv_sec; 1682 hp32->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1683 hp32->bh_datalen = pktlen; 1684 hp32->bh_hdrlen = hdrlen; 1685 hp32->bh_caplen = caplen; 1686 } else 1687 #endif 1688 { 1689 struct bpf_hdr *hp; 1690 1691 hp = (struct bpf_hdr *)h; 1692 hp->bh_tstamp.tv_sec = ts->tv_sec; 1693 hp->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1694 hp->bh_datalen = pktlen; 1695 hp->bh_hdrlen = hdrlen; 1696 hp->bh_caplen = caplen; 1697 } 1698 1699 /* 1700 * Copy the packet data into the store buffer and update its length. 1701 */ 1702 (*cpfn)(h + hdrlen, pkt, caplen); 1703 d->bd_slen = curlen + totlen; 1704 1705 /* 1706 * Call bpf_wakeup after bd_slen has been updated so that kevent(2) 1707 * will cause filt_bpfread() to be called with it adjusted. 1708 */ 1709 if (do_wakeup) 1710 bpf_wakeup(d); 1711 } 1712 1713 /* 1714 * Initialize all nonzero fields of a descriptor. 1715 */ 1716 static int 1717 bpf_allocbufs(struct bpf_d *d) 1718 { 1719 1720 d->bd_fbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL); 1721 if (!d->bd_fbuf) 1722 return (ENOBUFS); 1723 d->bd_sbuf = malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK | M_CANFAIL); 1724 if (!d->bd_sbuf) { 1725 free(d->bd_fbuf, M_DEVBUF); 1726 return (ENOBUFS); 1727 } 1728 d->bd_slen = 0; 1729 d->bd_hlen = 0; 1730 return (0); 1731 } 1732 1733 /* 1734 * Free buffers currently in use by a descriptor. 1735 * Called on close. 1736 */ 1737 static void 1738 bpf_freed(struct bpf_d *d) 1739 { 1740 /* 1741 * We don't need to lock out interrupts since this descriptor has 1742 * been detached from its interface and it yet hasn't been marked 1743 * free. 1744 */ 1745 if (d->bd_sbuf != NULL) { 1746 free(d->bd_sbuf, M_DEVBUF); 1747 if (d->bd_hbuf != NULL) 1748 free(d->bd_hbuf, M_DEVBUF); 1749 if (d->bd_fbuf != NULL) 1750 free(d->bd_fbuf, M_DEVBUF); 1751 } 1752 if (d->bd_filter) 1753 free(d->bd_filter, M_DEVBUF); 1754 1755 if (d->bd_jitcode != NULL) { 1756 bpf_jit_freecode(d->bd_jitcode); 1757 } 1758 } 1759 1760 /* 1761 * Attach an interface to bpf. dlt is the link layer type; 1762 * hdrlen is the fixed size of the link header for the specified dlt 1763 * (variable length headers not yet supported). 1764 */ 1765 static void 1766 _bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1767 { 1768 struct bpf_if *bp; 1769 bp = malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1770 if (bp == 0) 1771 panic("bpfattach"); 1772 1773 bp->bif_dlist = 0; 1774 bp->bif_driverp = driverp; 1775 bp->bif_ifp = ifp; 1776 bp->bif_dlt = dlt; 1777 1778 bp->bif_next = bpf_iflist; 1779 bpf_iflist = bp; 1780 1781 *bp->bif_driverp = 0; 1782 1783 bp->bif_hdrlen = hdrlen; 1784 #if 0 1785 printf("bpf: %s attached\n", ifp->if_xname); 1786 #endif 1787 } 1788 1789 /* 1790 * Remove an interface from bpf. 1791 */ 1792 static void 1793 _bpfdetach(struct ifnet *ifp) 1794 { 1795 struct bpf_if *bp, **pbp; 1796 struct bpf_d *d; 1797 int s; 1798 1799 /* Nuke the vnodes for any open instances */ 1800 LIST_FOREACH(d, &bpf_list, bd_list) { 1801 if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) { 1802 /* 1803 * Detach the descriptor from an interface now. 1804 * It will be free'ed later by close routine. 1805 */ 1806 s = splnet(); 1807 d->bd_promisc = 0; /* we can't touch device. */ 1808 bpf_detachd(d); 1809 splx(s); 1810 } 1811 } 1812 1813 again: 1814 for (bp = bpf_iflist, pbp = &bpf_iflist; 1815 bp != NULL; pbp = &bp->bif_next, bp = bp->bif_next) { 1816 if (bp->bif_ifp == ifp) { 1817 *pbp = bp->bif_next; 1818 free(bp, M_DEVBUF); 1819 goto again; 1820 } 1821 } 1822 } 1823 1824 /* 1825 * Change the data link type of a interface. 1826 */ 1827 static void 1828 _bpf_change_type(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1829 { 1830 struct bpf_if *bp; 1831 1832 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1833 if (bp->bif_driverp == &ifp->if_bpf) 1834 break; 1835 } 1836 if (bp == NULL) 1837 panic("bpf_change_type"); 1838 1839 bp->bif_dlt = dlt; 1840 1841 bp->bif_hdrlen = hdrlen; 1842 } 1843 1844 /* 1845 * Get a list of available data link type of the interface. 1846 */ 1847 static int 1848 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 1849 { 1850 int n, error; 1851 struct ifnet *ifp; 1852 struct bpf_if *bp; 1853 1854 ifp = d->bd_bif->bif_ifp; 1855 n = 0; 1856 error = 0; 1857 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1858 if (bp->bif_ifp != ifp) 1859 continue; 1860 if (bfl->bfl_list != NULL) { 1861 if (n >= bfl->bfl_len) 1862 return ENOMEM; 1863 error = copyout(&bp->bif_dlt, 1864 bfl->bfl_list + n, sizeof(u_int)); 1865 } 1866 n++; 1867 } 1868 bfl->bfl_len = n; 1869 return error; 1870 } 1871 1872 /* 1873 * Set the data link type of a BPF instance. 1874 */ 1875 static int 1876 bpf_setdlt(struct bpf_d *d, u_int dlt) 1877 { 1878 int s, error, opromisc; 1879 struct ifnet *ifp; 1880 struct bpf_if *bp; 1881 1882 if (d->bd_bif->bif_dlt == dlt) 1883 return 0; 1884 ifp = d->bd_bif->bif_ifp; 1885 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1886 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1887 break; 1888 } 1889 if (bp == NULL) 1890 return EINVAL; 1891 s = splnet(); 1892 opromisc = d->bd_promisc; 1893 bpf_detachd(d); 1894 bpf_attachd(d, bp); 1895 reset_d(d); 1896 if (opromisc) { 1897 error = ifpromisc(bp->bif_ifp, 1); 1898 if (error) 1899 printf("%s: bpf_setdlt: ifpromisc failed (%d)\n", 1900 bp->bif_ifp->if_xname, error); 1901 else 1902 d->bd_promisc = 1; 1903 } 1904 splx(s); 1905 return 0; 1906 } 1907 1908 static int 1909 sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS) 1910 { 1911 int newsize, error; 1912 struct sysctlnode node; 1913 1914 node = *rnode; 1915 node.sysctl_data = &newsize; 1916 newsize = bpf_maxbufsize; 1917 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1918 if (error || newp == NULL) 1919 return (error); 1920 1921 if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE) 1922 return (EINVAL); 1923 1924 bpf_maxbufsize = newsize; 1925 1926 return (0); 1927 } 1928 1929 static int 1930 sysctl_net_bpf_jit(SYSCTLFN_ARGS) 1931 { 1932 bool newval; 1933 int error; 1934 struct sysctlnode node; 1935 1936 node = *rnode; 1937 node.sysctl_data = &newval; 1938 newval = bpf_jit; 1939 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 1940 if (error != 0 || newp == NULL) 1941 return error; 1942 1943 bpf_jit = newval; 1944 1945 /* 1946 * Do a full sync to publish new bpf_jit value and 1947 * update bpfjit_module_ops.bj_generate_code variable. 1948 */ 1949 membar_sync(); 1950 1951 if (newval && bpfjit_module_ops.bj_generate_code == NULL) { 1952 printf("WARNING jit activation is postponed " 1953 "until after bpfjit module is loaded\n"); 1954 } 1955 1956 return 0; 1957 } 1958 1959 static int 1960 sysctl_net_bpf_peers(SYSCTLFN_ARGS) 1961 { 1962 int error, elem_count; 1963 struct bpf_d *dp; 1964 struct bpf_d_ext dpe; 1965 size_t len, needed, elem_size, out_size; 1966 char *sp; 1967 1968 if (namelen == 1 && name[0] == CTL_QUERY) 1969 return (sysctl_query(SYSCTLFN_CALL(rnode))); 1970 1971 if (namelen != 2) 1972 return (EINVAL); 1973 1974 /* BPF peers is privileged information. */ 1975 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_INTERFACE, 1976 KAUTH_REQ_NETWORK_INTERFACE_GETPRIV, NULL, NULL, NULL); 1977 if (error) 1978 return (EPERM); 1979 1980 len = (oldp != NULL) ? *oldlenp : 0; 1981 sp = oldp; 1982 elem_size = name[0]; 1983 elem_count = name[1]; 1984 out_size = MIN(sizeof(dpe), elem_size); 1985 needed = 0; 1986 1987 if (elem_size < 1 || elem_count < 0) 1988 return (EINVAL); 1989 1990 mutex_enter(&bpf_mtx); 1991 LIST_FOREACH(dp, &bpf_list, bd_list) { 1992 if (len >= elem_size && elem_count > 0) { 1993 #define BPF_EXT(field) dpe.bde_ ## field = dp->bd_ ## field 1994 BPF_EXT(bufsize); 1995 BPF_EXT(promisc); 1996 BPF_EXT(state); 1997 BPF_EXT(immediate); 1998 BPF_EXT(hdrcmplt); 1999 BPF_EXT(seesent); 2000 BPF_EXT(pid); 2001 BPF_EXT(rcount); 2002 BPF_EXT(dcount); 2003 BPF_EXT(ccount); 2004 #undef BPF_EXT 2005 if (dp->bd_bif) 2006 (void)strlcpy(dpe.bde_ifname, 2007 dp->bd_bif->bif_ifp->if_xname, 2008 IFNAMSIZ - 1); 2009 else 2010 dpe.bde_ifname[0] = '\0'; 2011 2012 error = copyout(&dpe, sp, out_size); 2013 if (error) 2014 break; 2015 sp += elem_size; 2016 len -= elem_size; 2017 } 2018 needed += elem_size; 2019 if (elem_count > 0 && elem_count != INT_MAX) 2020 elem_count--; 2021 } 2022 mutex_exit(&bpf_mtx); 2023 2024 *oldlenp = needed; 2025 2026 return (error); 2027 } 2028 2029 static struct sysctllog *bpf_sysctllog; 2030 static void 2031 sysctl_net_bpf_setup(void) 2032 { 2033 const struct sysctlnode *node; 2034 2035 node = NULL; 2036 sysctl_createv(&bpf_sysctllog, 0, NULL, &node, 2037 CTLFLAG_PERMANENT, 2038 CTLTYPE_NODE, "bpf", 2039 SYSCTL_DESCR("BPF options"), 2040 NULL, 0, NULL, 0, 2041 CTL_NET, CTL_CREATE, CTL_EOL); 2042 if (node != NULL) { 2043 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2044 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2045 CTLTYPE_BOOL, "jit", 2046 SYSCTL_DESCR("Toggle Just-In-Time compilation"), 2047 sysctl_net_bpf_jit, 0, &bpf_jit, 0, 2048 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2049 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2050 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2051 CTLTYPE_INT, "maxbufsize", 2052 SYSCTL_DESCR("Maximum size for data capture buffer"), 2053 sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0, 2054 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2055 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2056 CTLFLAG_PERMANENT, 2057 CTLTYPE_STRUCT, "stats", 2058 SYSCTL_DESCR("BPF stats"), 2059 NULL, 0, &bpf_gstats, sizeof(bpf_gstats), 2060 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2061 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2062 CTLFLAG_PERMANENT, 2063 CTLTYPE_STRUCT, "peers", 2064 SYSCTL_DESCR("BPF peers"), 2065 sysctl_net_bpf_peers, 0, NULL, 0, 2066 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2067 } 2068 2069 } 2070 2071 struct bpf_ops bpf_ops_kernel = { 2072 .bpf_attach = _bpfattach, 2073 .bpf_detach = _bpfdetach, 2074 .bpf_change_type = _bpf_change_type, 2075 2076 .bpf_tap = _bpf_tap, 2077 .bpf_mtap = _bpf_mtap, 2078 .bpf_mtap2 = _bpf_mtap2, 2079 .bpf_mtap_af = _bpf_mtap_af, 2080 .bpf_mtap_sl_in = _bpf_mtap_sl_in, 2081 .bpf_mtap_sl_out = _bpf_mtap_sl_out, 2082 }; 2083 2084 MODULE(MODULE_CLASS_DRIVER, bpf, NULL); 2085 2086 static int 2087 bpf_modcmd(modcmd_t cmd, void *arg) 2088 { 2089 devmajor_t bmajor, cmajor; 2090 int error; 2091 2092 bmajor = cmajor = NODEVMAJOR; 2093 2094 switch (cmd) { 2095 case MODULE_CMD_INIT: 2096 bpfilterattach(0); 2097 error = devsw_attach("bpf", NULL, &bmajor, 2098 &bpf_cdevsw, &cmajor); 2099 if (error == EEXIST) 2100 error = 0; /* maybe built-in ... improve eventually */ 2101 if (error) 2102 break; 2103 2104 bpf_ops_handover_enter(&bpf_ops_kernel); 2105 atomic_swap_ptr(&bpf_ops, &bpf_ops_kernel); 2106 bpf_ops_handover_exit(); 2107 sysctl_net_bpf_setup(); 2108 break; 2109 2110 case MODULE_CMD_FINI: 2111 /* 2112 * While there is no reference counting for bpf callers, 2113 * unload could at least in theory be done similarly to 2114 * system call disestablishment. This should even be 2115 * a little simpler: 2116 * 2117 * 1) replace op vector with stubs 2118 * 2) post update to all cpus with xc 2119 * 3) check that nobody is in bpf anymore 2120 * (it's doubtful we'd want something like l_sysent, 2121 * but we could do something like *signed* percpu 2122 * counters. if the sum is 0, we're good). 2123 * 4) if fail, unroll changes 2124 * 2125 * NOTE: change won't be atomic to the outside. some 2126 * packets may be not captured even if unload is 2127 * not succesful. I think packet capture not working 2128 * is a perfectly logical consequence of trying to 2129 * disable packet capture. 2130 */ 2131 error = EOPNOTSUPP; 2132 /* insert sysctl teardown */ 2133 break; 2134 2135 default: 2136 error = ENOTTY; 2137 break; 2138 } 2139 2140 return error; 2141 } 2142