Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/net/bpf.c
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1 /*- 2 * Copyright (c) 1990, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from the Stanford/CMU enet packet filter, 6 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 7 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 8 * Berkeley Laboratory. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)bpf.c 8.4 (Berkeley) 1/9/95 35 * 36 * $FreeBSD: releng/6.0/sys/net/bpf.c 150788 2005-10-01 18:43:16Z csjp $ 37 */ 38 39 #include "opt_bpf.h" 40 #include "opt_mac.h" 41 #include "opt_netgraph.h" 42 43 #include <sys/types.h> 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/conf.h> 47 #include <sys/fcntl.h> 48 #include <sys/mac.h> 49 #include <sys/malloc.h> 50 #include <sys/mbuf.h> 51 #include <sys/time.h> 52 #include <sys/proc.h> 53 #include <sys/signalvar.h> 54 #include <sys/filio.h> 55 #include <sys/sockio.h> 56 #include <sys/ttycom.h> 57 #include <sys/uio.h> 58 59 #include <sys/event.h> 60 #include <sys/file.h> 61 #include <sys/poll.h> 62 #include <sys/proc.h> 63 64 #include <sys/socket.h> 65 66 #include <net/if.h> 67 #include <net/bpf.h> 68 #include <net/bpfdesc.h> 69 70 #include <netinet/in.h> 71 #include <netinet/if_ether.h> 72 #include <sys/kernel.h> 73 #include <sys/sysctl.h> 74 75 static MALLOC_DEFINE(M_BPF, "BPF", "BPF data"); 76 77 #if defined(DEV_BPF) || defined(NETGRAPH_BPF) 78 79 #define PRINET 26 /* interruptible */ 80 81 /* 82 * bpf_iflist is a list of BPF interface structures, each corresponding to a 83 * specific DLT. The same network interface might have several BPF interface 84 * structures registered by different layers in the stack (i.e., 802.11 85 * frames, ethernet frames, etc). 86 */ 87 static LIST_HEAD(, bpf_if) bpf_iflist; 88 static struct mtx bpf_mtx; /* bpf global lock */ 89 static int bpf_bpfd_cnt; 90 91 static int bpf_allocbufs(struct bpf_d *); 92 static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp); 93 static void bpf_detachd(struct bpf_d *d); 94 static void bpf_freed(struct bpf_d *); 95 static void bpf_mcopy(const void *, void *, size_t); 96 static int bpf_movein(struct uio *, int, int, 97 struct mbuf **, struct sockaddr *, struct bpf_insn *); 98 static int bpf_setif(struct bpf_d *, struct ifreq *); 99 static void bpf_timed_out(void *); 100 static __inline void 101 bpf_wakeup(struct bpf_d *); 102 static void catchpacket(struct bpf_d *, u_char *, u_int, 103 u_int, void (*)(const void *, void *, size_t)); 104 static void reset_d(struct bpf_d *); 105 static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd); 106 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 107 static int bpf_setdlt(struct bpf_d *, u_int); 108 static void filt_bpfdetach(struct knote *); 109 static int filt_bpfread(struct knote *, long); 110 static void bpf_drvinit(void *); 111 static void bpf_clone(void *, struct ucred *, char *, int, struct cdev **); 112 static int bpf_stats_sysctl(SYSCTL_HANDLER_ARGS); 113 114 /* 115 * The default read buffer size is patchable. 116 */ 117 SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl"); 118 static int bpf_bufsize = 4096; 119 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 120 &bpf_bufsize, 0, ""); 121 static int bpf_maxbufsize = BPF_MAXBUFSIZE; 122 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 123 &bpf_maxbufsize, 0, ""); 124 static int bpf_maxinsns = BPF_MAXINSNS; 125 SYSCTL_INT(_net_bpf, OID_AUTO, maxinsns, CTLFLAG_RW, 126 &bpf_maxinsns, 0, "Maximum bpf program instructions"); 127 SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_RW, 128 bpf_stats_sysctl, "bpf statistics portal"); 129 130 static d_open_t bpfopen; 131 static d_close_t bpfclose; 132 static d_read_t bpfread; 133 static d_write_t bpfwrite; 134 static d_ioctl_t bpfioctl; 135 static d_poll_t bpfpoll; 136 static d_kqfilter_t bpfkqfilter; 137 138 static struct cdevsw bpf_cdevsw = { 139 .d_version = D_VERSION, 140 .d_flags = D_NEEDGIANT, 141 .d_open = bpfopen, 142 .d_close = bpfclose, 143 .d_read = bpfread, 144 .d_write = bpfwrite, 145 .d_ioctl = bpfioctl, 146 .d_poll = bpfpoll, 147 .d_name = "bpf", 148 .d_kqfilter = bpfkqfilter, 149 }; 150 151 static struct filterops bpfread_filtops = 152 { 1, NULL, filt_bpfdetach, filt_bpfread }; 153 154 static int 155 bpf_movein(uio, linktype, mtu, mp, sockp, wfilter) 156 struct uio *uio; 157 int linktype; 158 int mtu; 159 struct mbuf **mp; 160 struct sockaddr *sockp; 161 struct bpf_insn *wfilter; 162 { 163 struct mbuf *m; 164 int error; 165 int len; 166 int hlen; 167 int slen; 168 169 /* 170 * Build a sockaddr based on the data link layer type. 171 * We do this at this level because the ethernet header 172 * is copied directly into the data field of the sockaddr. 173 * In the case of SLIP, there is no header and the packet 174 * is forwarded as is. 175 * Also, we are careful to leave room at the front of the mbuf 176 * for the link level header. 177 */ 178 switch (linktype) { 179 180 case DLT_SLIP: 181 sockp->sa_family = AF_INET; 182 hlen = 0; 183 break; 184 185 case DLT_EN10MB: 186 sockp->sa_family = AF_UNSPEC; 187 /* XXX Would MAXLINKHDR be better? */ 188 hlen = ETHER_HDR_LEN; 189 break; 190 191 case DLT_FDDI: 192 sockp->sa_family = AF_IMPLINK; 193 hlen = 0; 194 break; 195 196 case DLT_RAW: 197 sockp->sa_family = AF_UNSPEC; 198 hlen = 0; 199 break; 200 201 case DLT_NULL: 202 /* 203 * null interface types require a 4 byte pseudo header which 204 * corresponds to the address family of the packet. 205 */ 206 sockp->sa_family = AF_UNSPEC; 207 hlen = 4; 208 break; 209 210 case DLT_ATM_RFC1483: 211 /* 212 * en atm driver requires 4-byte atm pseudo header. 213 * though it isn't standard, vpi:vci needs to be 214 * specified anyway. 215 */ 216 sockp->sa_family = AF_UNSPEC; 217 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */ 218 break; 219 220 case DLT_PPP: 221 sockp->sa_family = AF_UNSPEC; 222 hlen = 4; /* This should match PPP_HDRLEN */ 223 break; 224 225 default: 226 return (EIO); 227 } 228 229 len = uio->uio_resid; 230 231 if (len - hlen > mtu) 232 return (EMSGSIZE); 233 234 if ((unsigned)len > MCLBYTES) 235 return (EIO); 236 237 if (len > MHLEN) { 238 m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR); 239 } else { 240 MGETHDR(m, M_TRYWAIT, MT_DATA); 241 } 242 if (m == NULL) 243 return (ENOBUFS); 244 m->m_pkthdr.len = m->m_len = len; 245 m->m_pkthdr.rcvif = NULL; 246 *mp = m; 247 248 if (m->m_len < hlen) { 249 error = EPERM; 250 goto bad; 251 } 252 253 error = uiomove(mtod(m, u_char *), len, uio); 254 if (error) 255 goto bad; 256 257 slen = bpf_filter(wfilter, mtod(m, u_char *), len, len); 258 if (slen == 0) { 259 error = EPERM; 260 goto bad; 261 } 262 263 /* 264 * Make room for link header, and copy it to sockaddr 265 */ 266 if (hlen != 0) { 267 bcopy(m->m_data, sockp->sa_data, hlen); 268 m->m_pkthdr.len -= hlen; 269 m->m_len -= hlen; 270 #if BSD >= 199103 271 m->m_data += hlen; /* XXX */ 272 #else 273 m->m_off += hlen; 274 #endif 275 } 276 277 return (0); 278 bad: 279 m_freem(m); 280 return (error); 281 } 282 283 /* 284 * Attach file to the bpf interface, i.e. make d listen on bp. 285 */ 286 static void 287 bpf_attachd(d, bp) 288 struct bpf_d *d; 289 struct bpf_if *bp; 290 { 291 /* 292 * Point d at bp, and add d to the interface's list of listeners. 293 * Finally, point the driver's bpf cookie at the interface so 294 * it will divert packets to bpf. 295 */ 296 BPFIF_LOCK(bp); 297 d->bd_bif = bp; 298 LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); 299 300 bpf_bpfd_cnt++; 301 *bp->bif_driverp = bp; 302 BPFIF_UNLOCK(bp); 303 } 304 305 /* 306 * Detach a file from its interface. 307 */ 308 static void 309 bpf_detachd(d) 310 struct bpf_d *d; 311 { 312 int error; 313 struct bpf_if *bp; 314 struct ifnet *ifp; 315 316 bp = d->bd_bif; 317 BPFIF_LOCK(bp); 318 BPFD_LOCK(d); 319 ifp = d->bd_bif->bif_ifp; 320 321 /* 322 * Remove d from the interface's descriptor list. 323 */ 324 LIST_REMOVE(d, bd_next); 325 326 bpf_bpfd_cnt--; 327 /* 328 * Let the driver know that there are no more listeners. 329 */ 330 if (LIST_EMPTY(&bp->bif_dlist)) 331 *bp->bif_driverp = NULL; 332 333 d->bd_bif = NULL; 334 BPFD_UNLOCK(d); 335 BPFIF_UNLOCK(bp); 336 337 /* 338 * Check if this descriptor had requested promiscuous mode. 339 * If so, turn it off. 340 */ 341 if (d->bd_promisc) { 342 d->bd_promisc = 0; 343 error = ifpromisc(ifp, 0); 344 if (error != 0 && error != ENXIO) { 345 /* 346 * ENXIO can happen if a pccard is unplugged 347 * Something is really wrong if we were able to put 348 * the driver into promiscuous mode, but can't 349 * take it out. 350 */ 351 if_printf(bp->bif_ifp, 352 "bpf_detach: ifpromisc failed (%d)\n", error); 353 } 354 } 355 } 356 357 /* 358 * Open ethernet device. Returns ENXIO for illegal minor device number, 359 * EBUSY if file is open by another process. 360 */ 361 /* ARGSUSED */ 362 static int 363 bpfopen(dev, flags, fmt, td) 364 struct cdev *dev; 365 int flags; 366 int fmt; 367 struct thread *td; 368 { 369 struct bpf_d *d; 370 371 mtx_lock(&bpf_mtx); 372 d = dev->si_drv1; 373 /* 374 * Each minor can be opened by only one process. If the requested 375 * minor is in use, return EBUSY. 376 */ 377 if (d != NULL) { 378 mtx_unlock(&bpf_mtx); 379 return (EBUSY); 380 } 381 dev->si_drv1 = (struct bpf_d *)~0; /* mark device in use */ 382 mtx_unlock(&bpf_mtx); 383 384 if ((dev->si_flags & SI_NAMED) == 0) 385 make_dev(&bpf_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600, 386 "bpf%d", dev2unit(dev)); 387 MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK | M_ZERO); 388 dev->si_drv1 = d; 389 d->bd_bufsize = bpf_bufsize; 390 d->bd_sig = SIGIO; 391 d->bd_seesent = 1; 392 d->bd_pid = td->td_proc->p_pid; 393 strlcpy(d->bd_pcomm, td->td_proc->p_comm, MAXCOMLEN); 394 #ifdef MAC 395 mac_init_bpfdesc(d); 396 mac_create_bpfdesc(td->td_ucred, d); 397 #endif 398 mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF); 399 callout_init(&d->bd_callout, NET_CALLOUT_MPSAFE); 400 knlist_init(&d->bd_sel.si_note, &d->bd_mtx, NULL, NULL, NULL); 401 402 return (0); 403 } 404 405 /* 406 * Close the descriptor by detaching it from its interface, 407 * deallocating its buffers, and marking it free. 408 */ 409 /* ARGSUSED */ 410 static int 411 bpfclose(dev, flags, fmt, td) 412 struct cdev *dev; 413 int flags; 414 int fmt; 415 struct thread *td; 416 { 417 struct bpf_d *d = dev->si_drv1; 418 419 BPFD_LOCK(d); 420 if (d->bd_state == BPF_WAITING) 421 callout_stop(&d->bd_callout); 422 d->bd_state = BPF_IDLE; 423 BPFD_UNLOCK(d); 424 funsetown(&d->bd_sigio); 425 mtx_lock(&bpf_mtx); 426 if (d->bd_bif) 427 bpf_detachd(d); 428 mtx_unlock(&bpf_mtx); 429 selwakeuppri(&d->bd_sel, PRINET); 430 #ifdef MAC 431 mac_destroy_bpfdesc(d); 432 #endif /* MAC */ 433 knlist_destroy(&d->bd_sel.si_note); 434 bpf_freed(d); 435 dev->si_drv1 = NULL; 436 free(d, M_BPF); 437 438 return (0); 439 } 440 441 442 /* 443 * Rotate the packet buffers in descriptor d. Move the store buffer 444 * into the hold slot, and the free buffer into the store slot. 445 * Zero the length of the new store buffer. 446 */ 447 #define ROTATE_BUFFERS(d) \ 448 (d)->bd_hbuf = (d)->bd_sbuf; \ 449 (d)->bd_hlen = (d)->bd_slen; \ 450 (d)->bd_sbuf = (d)->bd_fbuf; \ 451 (d)->bd_slen = 0; \ 452 (d)->bd_fbuf = NULL; 453 /* 454 * bpfread - read next chunk of packets from buffers 455 */ 456 static int 457 bpfread(dev, uio, ioflag) 458 struct cdev *dev; 459 struct uio *uio; 460 int ioflag; 461 { 462 struct bpf_d *d = dev->si_drv1; 463 int timed_out; 464 int error; 465 466 /* 467 * Restrict application to use a buffer the same size as 468 * as kernel buffers. 469 */ 470 if (uio->uio_resid != d->bd_bufsize) 471 return (EINVAL); 472 473 BPFD_LOCK(d); 474 if (d->bd_state == BPF_WAITING) 475 callout_stop(&d->bd_callout); 476 timed_out = (d->bd_state == BPF_TIMED_OUT); 477 d->bd_state = BPF_IDLE; 478 /* 479 * If the hold buffer is empty, then do a timed sleep, which 480 * ends when the timeout expires or when enough packets 481 * have arrived to fill the store buffer. 482 */ 483 while (d->bd_hbuf == NULL) { 484 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 485 /* 486 * A packet(s) either arrived since the previous 487 * read or arrived while we were asleep. 488 * Rotate the buffers and return what's here. 489 */ 490 ROTATE_BUFFERS(d); 491 break; 492 } 493 494 /* 495 * No data is available, check to see if the bpf device 496 * is still pointed at a real interface. If not, return 497 * ENXIO so that the userland process knows to rebind 498 * it before using it again. 499 */ 500 if (d->bd_bif == NULL) { 501 BPFD_UNLOCK(d); 502 return (ENXIO); 503 } 504 505 if (ioflag & O_NONBLOCK) { 506 BPFD_UNLOCK(d); 507 return (EWOULDBLOCK); 508 } 509 error = msleep(d, &d->bd_mtx, PRINET|PCATCH, 510 "bpf", d->bd_rtout); 511 if (error == EINTR || error == ERESTART) { 512 BPFD_UNLOCK(d); 513 return (error); 514 } 515 if (error == EWOULDBLOCK) { 516 /* 517 * On a timeout, return what's in the buffer, 518 * which may be nothing. If there is something 519 * in the store buffer, we can rotate the buffers. 520 */ 521 if (d->bd_hbuf) 522 /* 523 * We filled up the buffer in between 524 * getting the timeout and arriving 525 * here, so we don't need to rotate. 526 */ 527 break; 528 529 if (d->bd_slen == 0) { 530 BPFD_UNLOCK(d); 531 return (0); 532 } 533 ROTATE_BUFFERS(d); 534 break; 535 } 536 } 537 /* 538 * At this point, we know we have something in the hold slot. 539 */ 540 BPFD_UNLOCK(d); 541 542 /* 543 * Move data from hold buffer into user space. 544 * We know the entire buffer is transferred since 545 * we checked above that the read buffer is bpf_bufsize bytes. 546 */ 547 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 548 549 BPFD_LOCK(d); 550 d->bd_fbuf = d->bd_hbuf; 551 d->bd_hbuf = NULL; 552 d->bd_hlen = 0; 553 BPFD_UNLOCK(d); 554 555 return (error); 556 } 557 558 559 /* 560 * If there are processes sleeping on this descriptor, wake them up. 561 */ 562 static __inline void 563 bpf_wakeup(d) 564 struct bpf_d *d; 565 { 566 567 BPFD_LOCK_ASSERT(d); 568 if (d->bd_state == BPF_WAITING) { 569 callout_stop(&d->bd_callout); 570 d->bd_state = BPF_IDLE; 571 } 572 wakeup(d); 573 if (d->bd_async && d->bd_sig && d->bd_sigio) 574 pgsigio(&d->bd_sigio, d->bd_sig, 0); 575 576 selwakeuppri(&d->bd_sel, PRINET); 577 KNOTE_LOCKED(&d->bd_sel.si_note, 0); 578 } 579 580 static void 581 bpf_timed_out(arg) 582 void *arg; 583 { 584 struct bpf_d *d = (struct bpf_d *)arg; 585 586 BPFD_LOCK(d); 587 if (d->bd_state == BPF_WAITING) { 588 d->bd_state = BPF_TIMED_OUT; 589 if (d->bd_slen != 0) 590 bpf_wakeup(d); 591 } 592 BPFD_UNLOCK(d); 593 } 594 595 static int 596 bpfwrite(dev, uio, ioflag) 597 struct cdev *dev; 598 struct uio *uio; 599 int ioflag; 600 { 601 struct bpf_d *d = dev->si_drv1; 602 struct ifnet *ifp; 603 struct mbuf *m; 604 int error; 605 struct sockaddr dst; 606 607 if (d->bd_bif == NULL) 608 return (ENXIO); 609 610 ifp = d->bd_bif->bif_ifp; 611 612 if ((ifp->if_flags & IFF_UP) == 0) 613 return (ENETDOWN); 614 615 if (uio->uio_resid == 0) 616 return (0); 617 618 bzero(&dst, sizeof(dst)); 619 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp->if_mtu, 620 &m, &dst, d->bd_wfilter); 621 if (error) 622 return (error); 623 624 if (d->bd_hdrcmplt) 625 dst.sa_family = pseudo_AF_HDRCMPLT; 626 627 #ifdef MAC 628 BPFD_LOCK(d); 629 mac_create_mbuf_from_bpfdesc(d, m); 630 BPFD_UNLOCK(d); 631 #endif 632 NET_LOCK_GIANT(); 633 error = (*ifp->if_output)(ifp, m, &dst, NULL); 634 NET_UNLOCK_GIANT(); 635 /* 636 * The driver frees the mbuf. 637 */ 638 return (error); 639 } 640 641 /* 642 * Reset a descriptor by flushing its packet buffer and clearing the 643 * receive and drop counts. 644 */ 645 static void 646 reset_d(d) 647 struct bpf_d *d; 648 { 649 650 mtx_assert(&d->bd_mtx, MA_OWNED); 651 if (d->bd_hbuf) { 652 /* Free the hold buffer. */ 653 d->bd_fbuf = d->bd_hbuf; 654 d->bd_hbuf = NULL; 655 } 656 d->bd_slen = 0; 657 d->bd_hlen = 0; 658 d->bd_rcount = 0; 659 d->bd_dcount = 0; 660 d->bd_fcount = 0; 661 } 662 663 /* 664 * FIONREAD Check for read packet available. 665 * SIOCGIFADDR Get interface address - convenient hook to driver. 666 * BIOCGBLEN Get buffer len [for read()]. 667 * BIOCSETF Set ethernet read filter. 668 * BIOCSETWF Set ethernet write filter. 669 * BIOCFLUSH Flush read packet buffer. 670 * BIOCPROMISC Put interface into promiscuous mode. 671 * BIOCGDLT Get link layer type. 672 * BIOCGETIF Get interface name. 673 * BIOCSETIF Set interface. 674 * BIOCSRTIMEOUT Set read timeout. 675 * BIOCGRTIMEOUT Get read timeout. 676 * BIOCGSTATS Get packet stats. 677 * BIOCIMMEDIATE Set immediate mode. 678 * BIOCVERSION Get filter language version. 679 * BIOCGHDRCMPLT Get "header already complete" flag 680 * BIOCSHDRCMPLT Set "header already complete" flag 681 * BIOCGSEESENT Get "see packets sent" flag 682 * BIOCSSEESENT Set "see packets sent" flag 683 * BIOCLOCK Set "locked" flag 684 */ 685 /* ARGSUSED */ 686 static int 687 bpfioctl(dev, cmd, addr, flags, td) 688 struct cdev *dev; 689 u_long cmd; 690 caddr_t addr; 691 int flags; 692 struct thread *td; 693 { 694 struct bpf_d *d = dev->si_drv1; 695 int error = 0; 696 697 /* 698 * Refresh PID associated with this descriptor. 699 */ 700 d->bd_pid = td->td_proc->p_pid; 701 BPFD_LOCK(d); 702 if (d->bd_state == BPF_WAITING) 703 callout_stop(&d->bd_callout); 704 d->bd_state = BPF_IDLE; 705 BPFD_UNLOCK(d); 706 707 if (d->bd_locked == 1) { 708 switch (cmd) { 709 case BIOCGBLEN: 710 case BIOCFLUSH: 711 case BIOCGDLT: 712 case BIOCGDLTLIST: 713 case BIOCGETIF: 714 case BIOCGRTIMEOUT: 715 case BIOCGSTATS: 716 case BIOCVERSION: 717 case BIOCGRSIG: 718 case BIOCGHDRCMPLT: 719 case FIONREAD: 720 case BIOCLOCK: 721 case BIOCSRTIMEOUT: 722 case BIOCIMMEDIATE: 723 case TIOCGPGRP: 724 break; 725 default: 726 return (EPERM); 727 } 728 } 729 switch (cmd) { 730 731 default: 732 error = EINVAL; 733 break; 734 735 /* 736 * Check for read packet available. 737 */ 738 case FIONREAD: 739 { 740 int n; 741 742 BPFD_LOCK(d); 743 n = d->bd_slen; 744 if (d->bd_hbuf) 745 n += d->bd_hlen; 746 BPFD_UNLOCK(d); 747 748 *(int *)addr = n; 749 break; 750 } 751 752 case SIOCGIFADDR: 753 { 754 struct ifnet *ifp; 755 756 if (d->bd_bif == NULL) 757 error = EINVAL; 758 else { 759 ifp = d->bd_bif->bif_ifp; 760 error = (*ifp->if_ioctl)(ifp, cmd, addr); 761 } 762 break; 763 } 764 765 /* 766 * Get buffer len [for read()]. 767 */ 768 case BIOCGBLEN: 769 *(u_int *)addr = d->bd_bufsize; 770 break; 771 772 /* 773 * Set buffer length. 774 */ 775 case BIOCSBLEN: 776 if (d->bd_bif != NULL) 777 error = EINVAL; 778 else { 779 u_int size = *(u_int *)addr; 780 781 if (size > bpf_maxbufsize) 782 *(u_int *)addr = size = bpf_maxbufsize; 783 else if (size < BPF_MINBUFSIZE) 784 *(u_int *)addr = size = BPF_MINBUFSIZE; 785 d->bd_bufsize = size; 786 } 787 break; 788 789 /* 790 * Set link layer read filter. 791 */ 792 case BIOCSETF: 793 case BIOCSETWF: 794 error = bpf_setf(d, (struct bpf_program *)addr, cmd); 795 break; 796 797 /* 798 * Flush read packet buffer. 799 */ 800 case BIOCFLUSH: 801 BPFD_LOCK(d); 802 reset_d(d); 803 BPFD_UNLOCK(d); 804 break; 805 806 /* 807 * Put interface into promiscuous mode. 808 */ 809 case BIOCPROMISC: 810 if (d->bd_bif == NULL) { 811 /* 812 * No interface attached yet. 813 */ 814 error = EINVAL; 815 break; 816 } 817 if (d->bd_promisc == 0) { 818 mtx_lock(&Giant); 819 error = ifpromisc(d->bd_bif->bif_ifp, 1); 820 mtx_unlock(&Giant); 821 if (error == 0) 822 d->bd_promisc = 1; 823 } 824 break; 825 826 /* 827 * Get current data link type. 828 */ 829 case BIOCGDLT: 830 if (d->bd_bif == NULL) 831 error = EINVAL; 832 else 833 *(u_int *)addr = d->bd_bif->bif_dlt; 834 break; 835 836 /* 837 * Get a list of supported data link types. 838 */ 839 case BIOCGDLTLIST: 840 if (d->bd_bif == NULL) 841 error = EINVAL; 842 else 843 error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); 844 break; 845 846 /* 847 * Set data link type. 848 */ 849 case BIOCSDLT: 850 if (d->bd_bif == NULL) 851 error = EINVAL; 852 else 853 error = bpf_setdlt(d, *(u_int *)addr); 854 break; 855 856 /* 857 * Get interface name. 858 */ 859 case BIOCGETIF: 860 if (d->bd_bif == NULL) 861 error = EINVAL; 862 else { 863 struct ifnet *const ifp = d->bd_bif->bif_ifp; 864 struct ifreq *const ifr = (struct ifreq *)addr; 865 866 strlcpy(ifr->ifr_name, ifp->if_xname, 867 sizeof(ifr->ifr_name)); 868 } 869 break; 870 871 /* 872 * Set interface. 873 */ 874 case BIOCSETIF: 875 error = bpf_setif(d, (struct ifreq *)addr); 876 break; 877 878 /* 879 * Set read timeout. 880 */ 881 case BIOCSRTIMEOUT: 882 { 883 struct timeval *tv = (struct timeval *)addr; 884 885 /* 886 * Subtract 1 tick from tvtohz() since this isn't 887 * a one-shot timer. 888 */ 889 if ((error = itimerfix(tv)) == 0) 890 d->bd_rtout = tvtohz(tv) - 1; 891 break; 892 } 893 894 /* 895 * Get read timeout. 896 */ 897 case BIOCGRTIMEOUT: 898 { 899 struct timeval *tv = (struct timeval *)addr; 900 901 tv->tv_sec = d->bd_rtout / hz; 902 tv->tv_usec = (d->bd_rtout % hz) * tick; 903 break; 904 } 905 906 /* 907 * Get packet stats. 908 */ 909 case BIOCGSTATS: 910 { 911 struct bpf_stat *bs = (struct bpf_stat *)addr; 912 913 bs->bs_recv = d->bd_rcount; 914 bs->bs_drop = d->bd_dcount; 915 break; 916 } 917 918 /* 919 * Set immediate mode. 920 */ 921 case BIOCIMMEDIATE: 922 d->bd_immediate = *(u_int *)addr; 923 break; 924 925 case BIOCVERSION: 926 { 927 struct bpf_version *bv = (struct bpf_version *)addr; 928 929 bv->bv_major = BPF_MAJOR_VERSION; 930 bv->bv_minor = BPF_MINOR_VERSION; 931 break; 932 } 933 934 /* 935 * Get "header already complete" flag 936 */ 937 case BIOCGHDRCMPLT: 938 *(u_int *)addr = d->bd_hdrcmplt; 939 break; 940 941 case BIOCLOCK: 942 d->bd_locked = 1; 943 break; 944 /* 945 * Set "header already complete" flag 946 */ 947 case BIOCSHDRCMPLT: 948 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 949 break; 950 951 /* 952 * Get "see sent packets" flag 953 */ 954 case BIOCGSEESENT: 955 *(u_int *)addr = d->bd_seesent; 956 break; 957 958 /* 959 * Set "see sent packets" flag 960 */ 961 case BIOCSSEESENT: 962 d->bd_seesent = *(u_int *)addr; 963 break; 964 965 case FIONBIO: /* Non-blocking I/O */ 966 break; 967 968 case FIOASYNC: /* Send signal on receive packets */ 969 d->bd_async = *(int *)addr; 970 break; 971 972 case FIOSETOWN: 973 error = fsetown(*(int *)addr, &d->bd_sigio); 974 break; 975 976 case FIOGETOWN: 977 *(int *)addr = fgetown(&d->bd_sigio); 978 break; 979 980 /* This is deprecated, FIOSETOWN should be used instead. */ 981 case TIOCSPGRP: 982 error = fsetown(-(*(int *)addr), &d->bd_sigio); 983 break; 984 985 /* This is deprecated, FIOGETOWN should be used instead. */ 986 case TIOCGPGRP: 987 *(int *)addr = -fgetown(&d->bd_sigio); 988 break; 989 990 case BIOCSRSIG: /* Set receive signal */ 991 { 992 u_int sig; 993 994 sig = *(u_int *)addr; 995 996 if (sig >= NSIG) 997 error = EINVAL; 998 else 999 d->bd_sig = sig; 1000 break; 1001 } 1002 case BIOCGRSIG: 1003 *(u_int *)addr = d->bd_sig; 1004 break; 1005 } 1006 return (error); 1007 } 1008 1009 /* 1010 * Set d's packet filter program to fp. If this file already has a filter, 1011 * free it and replace it. Returns EINVAL for bogus requests. 1012 */ 1013 static int 1014 bpf_setf(d, fp, cmd) 1015 struct bpf_d *d; 1016 struct bpf_program *fp; 1017 u_long cmd; 1018 { 1019 struct bpf_insn *fcode, *old; 1020 u_int wfilter, flen, size; 1021 1022 if (cmd == BIOCSETWF) { 1023 old = d->bd_wfilter; 1024 wfilter = 1; 1025 } else { 1026 wfilter = 0; 1027 old = d->bd_rfilter; 1028 } 1029 if (fp->bf_insns == NULL) { 1030 if (fp->bf_len != 0) 1031 return (EINVAL); 1032 BPFD_LOCK(d); 1033 if (wfilter) 1034 d->bd_wfilter = NULL; 1035 else 1036 d->bd_rfilter = NULL; 1037 reset_d(d); 1038 BPFD_UNLOCK(d); 1039 if (old != NULL) 1040 free((caddr_t)old, M_BPF); 1041 return (0); 1042 } 1043 flen = fp->bf_len; 1044 if (flen > bpf_maxinsns) 1045 return (EINVAL); 1046 1047 size = flen * sizeof(*fp->bf_insns); 1048 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK); 1049 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 1050 bpf_validate(fcode, (int)flen)) { 1051 BPFD_LOCK(d); 1052 if (wfilter) 1053 d->bd_wfilter = fcode; 1054 else 1055 d->bd_rfilter = fcode; 1056 reset_d(d); 1057 BPFD_UNLOCK(d); 1058 if (old != NULL) 1059 free((caddr_t)old, M_BPF); 1060 1061 return (0); 1062 } 1063 free((caddr_t)fcode, M_BPF); 1064 return (EINVAL); 1065 } 1066 1067 /* 1068 * Detach a file from its current interface (if attached at all) and attach 1069 * to the interface indicated by the name stored in ifr. 1070 * Return an errno or 0. 1071 */ 1072 static int 1073 bpf_setif(d, ifr) 1074 struct bpf_d *d; 1075 struct ifreq *ifr; 1076 { 1077 struct bpf_if *bp; 1078 int error; 1079 struct ifnet *theywant; 1080 1081 theywant = ifunit(ifr->ifr_name); 1082 if (theywant == NULL) 1083 return ENXIO; 1084 1085 /* 1086 * Look through attached interfaces for the named one. 1087 */ 1088 mtx_lock(&bpf_mtx); 1089 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1090 struct ifnet *ifp = bp->bif_ifp; 1091 1092 if (ifp == NULL || ifp != theywant) 1093 continue; 1094 /* skip additional entry */ 1095 if (bp->bif_driverp != &ifp->if_bpf) 1096 continue; 1097 1098 mtx_unlock(&bpf_mtx); 1099 /* 1100 * We found the requested interface. 1101 * Allocate the packet buffers if we need to. 1102 * If we're already attached to requested interface, 1103 * just flush the buffer. 1104 */ 1105 if (d->bd_sbuf == NULL) { 1106 error = bpf_allocbufs(d); 1107 if (error != 0) 1108 return (error); 1109 } 1110 if (bp != d->bd_bif) { 1111 if (d->bd_bif) 1112 /* 1113 * Detach if attached to something else. 1114 */ 1115 bpf_detachd(d); 1116 1117 bpf_attachd(d, bp); 1118 } 1119 BPFD_LOCK(d); 1120 reset_d(d); 1121 BPFD_UNLOCK(d); 1122 return (0); 1123 } 1124 mtx_unlock(&bpf_mtx); 1125 /* Not found. */ 1126 return (ENXIO); 1127 } 1128 1129 /* 1130 * Support for select() and poll() system calls 1131 * 1132 * Return true iff the specific operation will not block indefinitely. 1133 * Otherwise, return false but make a note that a selwakeup() must be done. 1134 */ 1135 static int 1136 bpfpoll(dev, events, td) 1137 struct cdev *dev; 1138 int events; 1139 struct thread *td; 1140 { 1141 struct bpf_d *d; 1142 int revents; 1143 1144 d = dev->si_drv1; 1145 if (d->bd_bif == NULL) 1146 return (ENXIO); 1147 1148 /* 1149 * Refresh PID associated with this descriptor. 1150 */ 1151 d->bd_pid = td->td_proc->p_pid; 1152 revents = events & (POLLOUT | POLLWRNORM); 1153 BPFD_LOCK(d); 1154 if (events & (POLLIN | POLLRDNORM)) { 1155 if (bpf_ready(d)) 1156 revents |= events & (POLLIN | POLLRDNORM); 1157 else { 1158 selrecord(td, &d->bd_sel); 1159 /* Start the read timeout if necessary. */ 1160 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1161 callout_reset(&d->bd_callout, d->bd_rtout, 1162 bpf_timed_out, d); 1163 d->bd_state = BPF_WAITING; 1164 } 1165 } 1166 } 1167 BPFD_UNLOCK(d); 1168 return (revents); 1169 } 1170 1171 /* 1172 * Support for kevent() system call. Register EVFILT_READ filters and 1173 * reject all others. 1174 */ 1175 int 1176 bpfkqfilter(dev, kn) 1177 struct cdev *dev; 1178 struct knote *kn; 1179 { 1180 struct bpf_d *d = (struct bpf_d *)dev->si_drv1; 1181 1182 if (kn->kn_filter != EVFILT_READ) 1183 return (1); 1184 1185 /* 1186 * Refresh PID associated with this descriptor. 1187 */ 1188 d->bd_pid = curthread->td_proc->p_pid; 1189 kn->kn_fop = &bpfread_filtops; 1190 kn->kn_hook = d; 1191 knlist_add(&d->bd_sel.si_note, kn, 0); 1192 1193 return (0); 1194 } 1195 1196 static void 1197 filt_bpfdetach(kn) 1198 struct knote *kn; 1199 { 1200 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1201 1202 knlist_remove(&d->bd_sel.si_note, kn, 0); 1203 } 1204 1205 static int 1206 filt_bpfread(kn, hint) 1207 struct knote *kn; 1208 long hint; 1209 { 1210 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1211 int ready; 1212 1213 BPFD_LOCK_ASSERT(d); 1214 ready = bpf_ready(d); 1215 if (ready) { 1216 kn->kn_data = d->bd_slen; 1217 if (d->bd_hbuf) 1218 kn->kn_data += d->bd_hlen; 1219 } 1220 else if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1221 callout_reset(&d->bd_callout, d->bd_rtout, 1222 bpf_timed_out, d); 1223 d->bd_state = BPF_WAITING; 1224 } 1225 1226 return (ready); 1227 } 1228 1229 /* 1230 * Incoming linkage from device drivers. Process the packet pkt, of length 1231 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1232 * by each process' filter, and if accepted, stashed into the corresponding 1233 * buffer. 1234 */ 1235 void 1236 bpf_tap(bp, pkt, pktlen) 1237 struct bpf_if *bp; 1238 u_char *pkt; 1239 u_int pktlen; 1240 { 1241 struct bpf_d *d; 1242 u_int slen; 1243 1244 /* 1245 * Lockless read to avoid cost of locking the interface if there are 1246 * no descriptors attached. 1247 */ 1248 if (LIST_EMPTY(&bp->bif_dlist)) 1249 return; 1250 1251 BPFIF_LOCK(bp); 1252 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1253 BPFD_LOCK(d); 1254 ++d->bd_rcount; 1255 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen); 1256 if (slen != 0) { 1257 d->bd_fcount++; 1258 #ifdef MAC 1259 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1260 #endif 1261 catchpacket(d, pkt, pktlen, slen, bcopy); 1262 } 1263 BPFD_UNLOCK(d); 1264 } 1265 BPFIF_UNLOCK(bp); 1266 } 1267 1268 /* 1269 * Copy data from an mbuf chain into a buffer. This code is derived 1270 * from m_copydata in sys/uipc_mbuf.c. 1271 */ 1272 static void 1273 bpf_mcopy(src_arg, dst_arg, len) 1274 const void *src_arg; 1275 void *dst_arg; 1276 size_t len; 1277 { 1278 const struct mbuf *m; 1279 u_int count; 1280 u_char *dst; 1281 1282 m = src_arg; 1283 dst = dst_arg; 1284 while (len > 0) { 1285 if (m == NULL) 1286 panic("bpf_mcopy"); 1287 count = min(m->m_len, len); 1288 bcopy(mtod(m, void *), dst, count); 1289 m = m->m_next; 1290 dst += count; 1291 len -= count; 1292 } 1293 } 1294 1295 /* 1296 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1297 */ 1298 void 1299 bpf_mtap(bp, m) 1300 struct bpf_if *bp; 1301 struct mbuf *m; 1302 { 1303 struct bpf_d *d; 1304 u_int pktlen, slen; 1305 1306 /* 1307 * Lockless read to avoid cost of locking the interface if there are 1308 * no descriptors attached. 1309 */ 1310 if (LIST_EMPTY(&bp->bif_dlist)) 1311 return; 1312 1313 pktlen = m_length(m, NULL); 1314 1315 BPFIF_LOCK(bp); 1316 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1317 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) 1318 continue; 1319 BPFD_LOCK(d); 1320 ++d->bd_rcount; 1321 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0); 1322 if (slen != 0) { 1323 d->bd_fcount++; 1324 #ifdef MAC 1325 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1326 #endif 1327 catchpacket(d, (u_char *)m, pktlen, slen, 1328 bpf_mcopy); 1329 } 1330 BPFD_UNLOCK(d); 1331 } 1332 BPFIF_UNLOCK(bp); 1333 } 1334 1335 /* 1336 * Incoming linkage from device drivers, when packet is in 1337 * an mbuf chain and to be prepended by a contiguous header. 1338 */ 1339 void 1340 bpf_mtap2(bp, data, dlen, m) 1341 struct bpf_if *bp; 1342 void *data; 1343 u_int dlen; 1344 struct mbuf *m; 1345 { 1346 struct mbuf mb; 1347 struct bpf_d *d; 1348 u_int pktlen, slen; 1349 1350 /* 1351 * Lockless read to avoid cost of locking the interface if there are 1352 * no descriptors attached. 1353 */ 1354 if (LIST_EMPTY(&bp->bif_dlist)) 1355 return; 1356 1357 pktlen = m_length(m, NULL); 1358 /* 1359 * Craft on-stack mbuf suitable for passing to bpf_filter. 1360 * Note that we cut corners here; we only setup what's 1361 * absolutely needed--this mbuf should never go anywhere else. 1362 */ 1363 mb.m_next = m; 1364 mb.m_data = data; 1365 mb.m_len = dlen; 1366 pktlen += dlen; 1367 1368 BPFIF_LOCK(bp); 1369 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1370 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) 1371 continue; 1372 BPFD_LOCK(d); 1373 ++d->bd_rcount; 1374 slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0); 1375 if (slen != 0) { 1376 d->bd_fcount++; 1377 #ifdef MAC 1378 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1379 #endif 1380 catchpacket(d, (u_char *)&mb, pktlen, slen, 1381 bpf_mcopy); 1382 } 1383 BPFD_UNLOCK(d); 1384 } 1385 BPFIF_UNLOCK(bp); 1386 } 1387 1388 /* 1389 * Move the packet data from interface memory (pkt) into the 1390 * store buffer. "cpfn" is the routine called to do the actual data 1391 * transfer. bcopy is passed in to copy contiguous chunks, while 1392 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1393 * pkt is really an mbuf. 1394 */ 1395 static void 1396 catchpacket(d, pkt, pktlen, snaplen, cpfn) 1397 struct bpf_d *d; 1398 u_char *pkt; 1399 u_int pktlen, snaplen; 1400 void (*cpfn)(const void *, void *, size_t); 1401 { 1402 struct bpf_hdr *hp; 1403 int totlen, curlen; 1404 int hdrlen = d->bd_bif->bif_hdrlen; 1405 int do_wakeup = 0; 1406 1407 BPFD_LOCK_ASSERT(d); 1408 /* 1409 * Figure out how many bytes to move. If the packet is 1410 * greater or equal to the snapshot length, transfer that 1411 * much. Otherwise, transfer the whole packet (unless 1412 * we hit the buffer size limit). 1413 */ 1414 totlen = hdrlen + min(snaplen, pktlen); 1415 if (totlen > d->bd_bufsize) 1416 totlen = d->bd_bufsize; 1417 1418 /* 1419 * Round up the end of the previous packet to the next longword. 1420 */ 1421 curlen = BPF_WORDALIGN(d->bd_slen); 1422 if (curlen + totlen > d->bd_bufsize) { 1423 /* 1424 * This packet will overflow the storage buffer. 1425 * Rotate the buffers if we can, then wakeup any 1426 * pending reads. 1427 */ 1428 if (d->bd_fbuf == NULL) { 1429 /* 1430 * We haven't completed the previous read yet, 1431 * so drop the packet. 1432 */ 1433 ++d->bd_dcount; 1434 return; 1435 } 1436 ROTATE_BUFFERS(d); 1437 do_wakeup = 1; 1438 curlen = 0; 1439 } 1440 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) 1441 /* 1442 * Immediate mode is set, or the read timeout has 1443 * already expired during a select call. A packet 1444 * arrived, so the reader should be woken up. 1445 */ 1446 do_wakeup = 1; 1447 1448 /* 1449 * Append the bpf header. 1450 */ 1451 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1452 microtime(&hp->bh_tstamp); 1453 hp->bh_datalen = pktlen; 1454 hp->bh_hdrlen = hdrlen; 1455 /* 1456 * Copy the packet data into the store buffer and update its length. 1457 */ 1458 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1459 d->bd_slen = curlen + totlen; 1460 1461 if (do_wakeup) 1462 bpf_wakeup(d); 1463 } 1464 1465 /* 1466 * Initialize all nonzero fields of a descriptor. 1467 */ 1468 static int 1469 bpf_allocbufs(d) 1470 struct bpf_d *d; 1471 { 1472 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1473 if (d->bd_fbuf == NULL) 1474 return (ENOBUFS); 1475 1476 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1477 if (d->bd_sbuf == NULL) { 1478 free(d->bd_fbuf, M_BPF); 1479 return (ENOBUFS); 1480 } 1481 d->bd_slen = 0; 1482 d->bd_hlen = 0; 1483 return (0); 1484 } 1485 1486 /* 1487 * Free buffers currently in use by a descriptor. 1488 * Called on close. 1489 */ 1490 static void 1491 bpf_freed(d) 1492 struct bpf_d *d; 1493 { 1494 /* 1495 * We don't need to lock out interrupts since this descriptor has 1496 * been detached from its interface and it yet hasn't been marked 1497 * free. 1498 */ 1499 if (d->bd_sbuf != NULL) { 1500 free(d->bd_sbuf, M_BPF); 1501 if (d->bd_hbuf != NULL) 1502 free(d->bd_hbuf, M_BPF); 1503 if (d->bd_fbuf != NULL) 1504 free(d->bd_fbuf, M_BPF); 1505 } 1506 if (d->bd_rfilter) 1507 free((caddr_t)d->bd_rfilter, M_BPF); 1508 if (d->bd_wfilter) 1509 free((caddr_t)d->bd_wfilter, M_BPF); 1510 mtx_destroy(&d->bd_mtx); 1511 } 1512 1513 /* 1514 * Attach an interface to bpf. dlt is the link layer type; hdrlen is the 1515 * fixed size of the link header (variable length headers not yet supported). 1516 */ 1517 void 1518 bpfattach(ifp, dlt, hdrlen) 1519 struct ifnet *ifp; 1520 u_int dlt, hdrlen; 1521 { 1522 1523 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); 1524 } 1525 1526 /* 1527 * Attach an interface to bpf. ifp is a pointer to the structure 1528 * defining the interface to be attached, dlt is the link layer type, 1529 * and hdrlen is the fixed size of the link header (variable length 1530 * headers are not yet supporrted). 1531 */ 1532 void 1533 bpfattach2(ifp, dlt, hdrlen, driverp) 1534 struct ifnet *ifp; 1535 u_int dlt, hdrlen; 1536 struct bpf_if **driverp; 1537 { 1538 struct bpf_if *bp; 1539 bp = (struct bpf_if *)malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO); 1540 if (bp == NULL) 1541 panic("bpfattach"); 1542 1543 LIST_INIT(&bp->bif_dlist); 1544 bp->bif_driverp = driverp; 1545 bp->bif_ifp = ifp; 1546 bp->bif_dlt = dlt; 1547 mtx_init(&bp->bif_mtx, "bpf interface lock", NULL, MTX_DEF); 1548 1549 mtx_lock(&bpf_mtx); 1550 LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next); 1551 mtx_unlock(&bpf_mtx); 1552 1553 *bp->bif_driverp = NULL; 1554 1555 /* 1556 * Compute the length of the bpf header. This is not necessarily 1557 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1558 * that the network layer header begins on a longword boundary (for 1559 * performance reasons and to alleviate alignment restrictions). 1560 */ 1561 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1562 1563 if (bootverbose) 1564 if_printf(ifp, "bpf attached\n"); 1565 } 1566 1567 /* 1568 * Detach bpf from an interface. This involves detaching each descriptor 1569 * associated with the interface, and leaving bd_bif NULL. Notify each 1570 * descriptor as it's detached so that any sleepers wake up and get 1571 * ENXIO. 1572 */ 1573 void 1574 bpfdetach(ifp) 1575 struct ifnet *ifp; 1576 { 1577 struct bpf_if *bp; 1578 struct bpf_d *d; 1579 1580 /* Locate BPF interface information */ 1581 mtx_lock(&bpf_mtx); 1582 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1583 if (ifp == bp->bif_ifp) 1584 break; 1585 } 1586 1587 /* Interface wasn't attached */ 1588 if ((bp == NULL) || (bp->bif_ifp == NULL)) { 1589 mtx_unlock(&bpf_mtx); 1590 printf("bpfdetach: %s was not attached\n", ifp->if_xname); 1591 return; 1592 } 1593 1594 LIST_REMOVE(bp, bif_next); 1595 mtx_unlock(&bpf_mtx); 1596 1597 while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) { 1598 bpf_detachd(d); 1599 BPFD_LOCK(d); 1600 bpf_wakeup(d); 1601 BPFD_UNLOCK(d); 1602 } 1603 1604 mtx_destroy(&bp->bif_mtx); 1605 free(bp, M_BPF); 1606 } 1607 1608 /* 1609 * Get a list of available data link type of the interface. 1610 */ 1611 static int 1612 bpf_getdltlist(d, bfl) 1613 struct bpf_d *d; 1614 struct bpf_dltlist *bfl; 1615 { 1616 int n, error; 1617 struct ifnet *ifp; 1618 struct bpf_if *bp; 1619 1620 ifp = d->bd_bif->bif_ifp; 1621 n = 0; 1622 error = 0; 1623 mtx_lock(&bpf_mtx); 1624 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1625 if (bp->bif_ifp != ifp) 1626 continue; 1627 if (bfl->bfl_list != NULL) { 1628 if (n >= bfl->bfl_len) { 1629 mtx_unlock(&bpf_mtx); 1630 return (ENOMEM); 1631 } 1632 error = copyout(&bp->bif_dlt, 1633 bfl->bfl_list + n, sizeof(u_int)); 1634 } 1635 n++; 1636 } 1637 mtx_unlock(&bpf_mtx); 1638 bfl->bfl_len = n; 1639 return (error); 1640 } 1641 1642 /* 1643 * Set the data link type of a BPF instance. 1644 */ 1645 static int 1646 bpf_setdlt(d, dlt) 1647 struct bpf_d *d; 1648 u_int dlt; 1649 { 1650 int error, opromisc; 1651 struct ifnet *ifp; 1652 struct bpf_if *bp; 1653 1654 if (d->bd_bif->bif_dlt == dlt) 1655 return (0); 1656 ifp = d->bd_bif->bif_ifp; 1657 mtx_lock(&bpf_mtx); 1658 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1659 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1660 break; 1661 } 1662 mtx_unlock(&bpf_mtx); 1663 if (bp != NULL) { 1664 opromisc = d->bd_promisc; 1665 bpf_detachd(d); 1666 bpf_attachd(d, bp); 1667 BPFD_LOCK(d); 1668 reset_d(d); 1669 BPFD_UNLOCK(d); 1670 if (opromisc) { 1671 error = ifpromisc(bp->bif_ifp, 1); 1672 if (error) 1673 if_printf(bp->bif_ifp, 1674 "bpf_setdlt: ifpromisc failed (%d)\n", 1675 error); 1676 else 1677 d->bd_promisc = 1; 1678 } 1679 } 1680 return (bp == NULL ? EINVAL : 0); 1681 } 1682 1683 static void 1684 bpf_clone(arg, cred, name, namelen, dev) 1685 void *arg; 1686 struct ucred *cred; 1687 char *name; 1688 int namelen; 1689 struct cdev **dev; 1690 { 1691 int u; 1692 1693 if (*dev != NULL) 1694 return; 1695 if (dev_stdclone(name, NULL, "bpf", &u) != 1) 1696 return; 1697 *dev = make_dev(&bpf_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 1698 "bpf%d", u); 1699 dev_ref(*dev); 1700 (*dev)->si_flags |= SI_CHEAPCLONE; 1701 return; 1702 } 1703 1704 static void 1705 bpf_drvinit(unused) 1706 void *unused; 1707 { 1708 1709 mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF); 1710 LIST_INIT(&bpf_iflist); 1711 EVENTHANDLER_REGISTER(dev_clone, bpf_clone, 0, 1000); 1712 } 1713 1714 static void 1715 bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd) 1716 { 1717 1718 bzero(d, sizeof(*d)); 1719 BPFD_LOCK_ASSERT(bd); 1720 d->bd_immediate = bd->bd_immediate; 1721 d->bd_promisc = bd->bd_promisc; 1722 d->bd_hdrcmplt = bd->bd_hdrcmplt; 1723 d->bd_seesent = bd->bd_seesent; 1724 d->bd_async = bd->bd_async; 1725 d->bd_rcount = bd->bd_rcount; 1726 d->bd_dcount = bd->bd_dcount; 1727 d->bd_fcount = bd->bd_fcount; 1728 d->bd_sig = bd->bd_sig; 1729 d->bd_slen = bd->bd_slen; 1730 d->bd_hlen = bd->bd_hlen; 1731 d->bd_bufsize = bd->bd_bufsize; 1732 d->bd_pid = bd->bd_pid; 1733 strlcpy(d->bd_ifname, 1734 bd->bd_bif->bif_ifp->if_xname, IFNAMSIZ); 1735 strlcpy(d->bd_pcomm, bd->bd_pcomm, MAXCOMLEN); 1736 d->bd_locked = bd->bd_locked; 1737 } 1738 1739 static int 1740 bpf_stats_sysctl(SYSCTL_HANDLER_ARGS) 1741 { 1742 struct xbpf_d *xbdbuf, *xbd; 1743 int index, error; 1744 struct bpf_if *bp; 1745 struct bpf_d *bd; 1746 1747 /* 1748 * XXX This is not technically correct. It is possible for non 1749 * privileged users to open bpf devices. It would make sense 1750 * if the users who opened the devices were able to retrieve 1751 * the statistics for them, too. 1752 */ 1753 error = suser(req->td); 1754 if (error) 1755 return (error); 1756 if (req->oldptr == NULL) 1757 return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd))); 1758 if (bpf_bpfd_cnt == 0) 1759 return (SYSCTL_OUT(req, 0, 0)); 1760 xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK); 1761 mtx_lock(&bpf_mtx); 1762 if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) { 1763 mtx_unlock(&bpf_mtx); 1764 free(xbdbuf, M_BPF); 1765 return (ENOMEM); 1766 } 1767 index = 0; 1768 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1769 LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { 1770 xbd = &xbdbuf[index++]; 1771 BPFD_LOCK(bd); 1772 bpfstats_fill_xbpf(xbd, bd); 1773 BPFD_UNLOCK(bd); 1774 } 1775 } 1776 mtx_unlock(&bpf_mtx); 1777 error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd)); 1778 free(xbdbuf, M_BPF); 1779 return (error); 1780 } 1781 1782 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,bpf_drvinit,NULL) 1783 1784 #else /* !DEV_BPF && !NETGRAPH_BPF */ 1785 /* 1786 * NOP stubs to allow bpf-using drivers to load and function. 1787 * 1788 * A 'better' implementation would allow the core bpf functionality 1789 * to be loaded at runtime. 1790 */ 1791 1792 void 1793 bpf_tap(bp, pkt, pktlen) 1794 struct bpf_if *bp; 1795 u_char *pkt; 1796 u_int pktlen; 1797 { 1798 } 1799 1800 void 1801 bpf_mtap(bp, m) 1802 struct bpf_if *bp; 1803 struct mbuf *m; 1804 { 1805 } 1806 1807 void 1808 bpf_mtap2(bp, d, l, m) 1809 struct bpf_if *bp; 1810 void *d; 1811 u_int l; 1812 struct mbuf *m; 1813 { 1814 } 1815 1816 void 1817 bpfattach(ifp, dlt, hdrlen) 1818 struct ifnet *ifp; 1819 u_int dlt, hdrlen; 1820 { 1821 } 1822 1823 void 1824 bpfattach2(ifp, dlt, hdrlen, driverp) 1825 struct ifnet *ifp; 1826 u_int dlt, hdrlen; 1827 struct bpf_if **driverp; 1828 { 1829 } 1830 1831 void 1832 bpfdetach(ifp) 1833 struct ifnet *ifp; 1834 { 1835 } 1836 1837 u_int 1838 bpf_filter(pc, p, wirelen, buflen) 1839 const struct bpf_insn *pc; 1840 u_char *p; 1841 u_int wirelen; 1842 u_int buflen; 1843 { 1844 return -1; /* "no filter" behaviour */ 1845 } 1846 1847 int 1848 bpf_validate(f, len) 1849 const struct bpf_insn *f; 1850 int len; 1851 { 1852 return 0; /* false */ 1853 } 1854 1855 #endif /* !DEV_BPF && !NETGRAPH_BPF */
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