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/6.4/sys/net/bpf.c 181388 2008-08-07 20:06:49Z jkim $ 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 *, struct bpf_if *); 93 static void bpf_detachd(struct bpf_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, struct ifnet *, 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 struct timeval *); 105 static void reset_d(struct bpf_d *); 106 static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd); 107 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 108 static int bpf_setdlt(struct bpf_d *, u_int); 109 static void filt_bpfdetach(struct knote *); 110 static int filt_bpfread(struct knote *, long); 111 static void bpf_drvinit(void *); 112 static void bpf_clone(void *, struct ucred *, char *, int, struct cdev **); 113 static int bpf_stats_sysctl(SYSCTL_HANDLER_ARGS); 114 115 /* 116 * The default read buffer size is patchable. 117 */ 118 SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl"); 119 static int bpf_bufsize = 4096; 120 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 121 &bpf_bufsize, 0, ""); 122 static int bpf_maxbufsize = BPF_MAXBUFSIZE; 123 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 124 &bpf_maxbufsize, 0, ""); 125 static int bpf_maxinsns = BPF_MAXINSNS; 126 SYSCTL_INT(_net_bpf, OID_AUTO, maxinsns, CTLFLAG_RW, 127 &bpf_maxinsns, 0, "Maximum bpf program instructions"); 128 SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_RW, 129 bpf_stats_sysctl, "bpf statistics portal"); 130 131 static d_open_t bpfopen; 132 static d_close_t bpfclose; 133 static d_read_t bpfread; 134 static d_write_t bpfwrite; 135 static d_ioctl_t bpfioctl; 136 static d_poll_t bpfpoll; 137 static d_kqfilter_t bpfkqfilter; 138 139 static struct cdevsw bpf_cdevsw = { 140 .d_version = D_VERSION, 141 .d_flags = D_NEEDGIANT | D_TRACKCLOSE, 142 .d_open = bpfopen, 143 .d_close = bpfclose, 144 .d_read = bpfread, 145 .d_write = bpfwrite, 146 .d_ioctl = bpfioctl, 147 .d_poll = bpfpoll, 148 .d_name = "bpf", 149 .d_kqfilter = bpfkqfilter, 150 }; 151 152 static struct filterops bpfread_filtops = 153 { 1, NULL, filt_bpfdetach, filt_bpfread }; 154 155 static int 156 bpf_movein(struct uio *uio, int linktype, struct ifnet *ifp, struct mbuf **mp, 157 struct sockaddr *sockp, struct bpf_insn *wfilter) 158 { 159 struct ether_header *eh; 160 struct mbuf *m; 161 int error; 162 int len; 163 int hlen; 164 int slen; 165 166 /* 167 * Build a sockaddr based on the data link layer type. 168 * We do this at this level because the ethernet header 169 * is copied directly into the data field of the sockaddr. 170 * In the case of SLIP, there is no header and the packet 171 * is forwarded as is. 172 * Also, we are careful to leave room at the front of the mbuf 173 * for the link level header. 174 */ 175 switch (linktype) { 176 177 case DLT_SLIP: 178 sockp->sa_family = AF_INET; 179 hlen = 0; 180 break; 181 182 case DLT_EN10MB: 183 sockp->sa_family = AF_UNSPEC; 184 /* XXX Would MAXLINKHDR be better? */ 185 hlen = ETHER_HDR_LEN; 186 break; 187 188 case DLT_FDDI: 189 sockp->sa_family = AF_IMPLINK; 190 hlen = 0; 191 break; 192 193 case DLT_RAW: 194 sockp->sa_family = AF_UNSPEC; 195 hlen = 0; 196 break; 197 198 case DLT_NULL: 199 /* 200 * null interface types require a 4 byte pseudo header which 201 * corresponds to the address family of the packet. 202 */ 203 sockp->sa_family = AF_UNSPEC; 204 hlen = 4; 205 break; 206 207 case DLT_ATM_RFC1483: 208 /* 209 * en atm driver requires 4-byte atm pseudo header. 210 * though it isn't standard, vpi:vci needs to be 211 * specified anyway. 212 */ 213 sockp->sa_family = AF_UNSPEC; 214 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */ 215 break; 216 217 case DLT_PPP: 218 sockp->sa_family = AF_UNSPEC; 219 hlen = 4; /* This should match PPP_HDRLEN */ 220 break; 221 222 default: 223 return (EIO); 224 } 225 226 len = uio->uio_resid; 227 228 if (len - hlen > ifp->if_mtu) 229 return (EMSGSIZE); 230 231 if ((unsigned)len > MJUM16BYTES) 232 return (EIO); 233 234 if (len <= MHLEN) 235 MGETHDR(m, M_TRYWAIT, MT_DATA); 236 else if (len <= MCLBYTES) 237 m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR); 238 else 239 m = m_getjcl(M_TRYWAIT, MT_DATA, M_PKTHDR, 240 #if (MJUMPAGESIZE > MCLBYTES) 241 len <= MJUMPAGESIZE ? MJUMPAGESIZE : 242 #endif 243 (len <= MJUM9BYTES ? MJUM9BYTES : MJUM16BYTES)); 244 if (m == NULL) 245 return (ENOBUFS); 246 m->m_pkthdr.len = m->m_len = len; 247 m->m_pkthdr.rcvif = NULL; 248 *mp = m; 249 250 if (m->m_len < hlen) { 251 error = EPERM; 252 goto bad; 253 } 254 255 error = uiomove(mtod(m, u_char *), len, uio); 256 if (error) 257 goto bad; 258 259 slen = bpf_filter(wfilter, mtod(m, u_char *), len, len); 260 if (slen == 0) { 261 error = EPERM; 262 goto bad; 263 } 264 265 /* Check for multicast destination */ 266 switch (linktype) { 267 case DLT_EN10MB: 268 eh = mtod(m, struct ether_header *); 269 if (ETHER_IS_MULTICAST(eh->ether_dhost)) { 270 if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost, 271 ETHER_ADDR_LEN) == 0) 272 m->m_flags |= M_BCAST; 273 else 274 m->m_flags |= M_MCAST; 275 } 276 break; 277 } 278 279 /* 280 * Make room for link header, and copy it to sockaddr 281 */ 282 if (hlen != 0) { 283 bcopy(m->m_data, sockp->sa_data, hlen); 284 m->m_pkthdr.len -= hlen; 285 m->m_len -= hlen; 286 #if BSD >= 199103 287 m->m_data += hlen; /* XXX */ 288 #else 289 m->m_off += hlen; 290 #endif 291 } 292 293 return (0); 294 bad: 295 m_freem(m); 296 return (error); 297 } 298 299 /* 300 * Attach file to the bpf interface, i.e. make d listen on bp. 301 */ 302 static void 303 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 304 { 305 /* 306 * Point d at bp, and add d to the interface's list of listeners. 307 * Finally, point the driver's bpf cookie at the interface so 308 * it will divert packets to bpf. 309 */ 310 BPFIF_LOCK(bp); 311 d->bd_bif = bp; 312 LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); 313 314 bpf_bpfd_cnt++; 315 BPFIF_UNLOCK(bp); 316 } 317 318 /* 319 * Detach a file from its interface. 320 */ 321 static void 322 bpf_detachd(struct bpf_d *d) 323 { 324 int error; 325 struct bpf_if *bp; 326 struct ifnet *ifp; 327 328 bp = d->bd_bif; 329 BPFIF_LOCK(bp); 330 BPFD_LOCK(d); 331 ifp = d->bd_bif->bif_ifp; 332 333 /* 334 * Remove d from the interface's descriptor list. 335 */ 336 LIST_REMOVE(d, bd_next); 337 338 bpf_bpfd_cnt--; 339 d->bd_bif = NULL; 340 BPFD_UNLOCK(d); 341 BPFIF_UNLOCK(bp); 342 343 /* 344 * Check if this descriptor had requested promiscuous mode. 345 * If so, turn it off. 346 */ 347 if (d->bd_promisc) { 348 d->bd_promisc = 0; 349 error = ifpromisc(ifp, 0); 350 if (error != 0 && error != ENXIO) { 351 /* 352 * ENXIO can happen if a pccard is unplugged 353 * Something is really wrong if we were able to put 354 * the driver into promiscuous mode, but can't 355 * take it out. 356 */ 357 if_printf(bp->bif_ifp, 358 "bpf_detach: ifpromisc failed (%d)\n", error); 359 } 360 } 361 } 362 363 /* 364 * Open ethernet device. Returns ENXIO for illegal minor device number, 365 * EBUSY if file is open by another process. 366 */ 367 /* ARGSUSED */ 368 static int 369 bpfopen(struct cdev *dev, int flags, int fmt, struct thread *td) 370 { 371 struct bpf_d *d; 372 373 mtx_lock(&bpf_mtx); 374 d = dev->si_drv1; 375 /* 376 * Each minor can be opened by only one process. If the requested 377 * minor is in use, return EBUSY. 378 */ 379 if (d != NULL) { 380 mtx_unlock(&bpf_mtx); 381 return (EBUSY); 382 } 383 dev->si_drv1 = (struct bpf_d *)~0; /* mark device in use */ 384 mtx_unlock(&bpf_mtx); 385 386 if ((dev->si_flags & SI_NAMED) == 0) 387 make_dev(&bpf_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600, 388 "bpf%d", dev2unit(dev)); 389 MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK | M_ZERO); 390 dev->si_drv1 = d; 391 d->bd_bufsize = bpf_bufsize; 392 d->bd_sig = SIGIO; 393 d->bd_seesent = 1; 394 d->bd_pid = td->td_proc->p_pid; 395 strlcpy(d->bd_pcomm, td->td_proc->p_comm, MAXCOMLEN); 396 #ifdef MAC 397 mac_init_bpfdesc(d); 398 mac_create_bpfdesc(td->td_ucred, d); 399 #endif 400 mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF); 401 callout_init(&d->bd_callout, NET_CALLOUT_MPSAFE); 402 knlist_init(&d->bd_sel.si_note, &d->bd_mtx, NULL, NULL, NULL); 403 404 return (0); 405 } 406 407 /* 408 * Close the descriptor by detaching it from its interface, 409 * deallocating its buffers, and marking it free. 410 */ 411 /* ARGSUSED */ 412 static int 413 bpfclose(struct cdev *dev, int flags, int fmt, struct thread *td) 414 { 415 struct bpf_d *d = dev->si_drv1; 416 417 BPFD_LOCK(d); 418 if (d->bd_state == BPF_WAITING) 419 callout_stop(&d->bd_callout); 420 d->bd_state = BPF_IDLE; 421 BPFD_UNLOCK(d); 422 funsetown(&d->bd_sigio); 423 mtx_lock(&bpf_mtx); 424 if (d->bd_bif) 425 bpf_detachd(d); 426 mtx_unlock(&bpf_mtx); 427 selwakeuppri(&d->bd_sel, PRINET); 428 #ifdef MAC 429 mac_destroy_bpfdesc(d); 430 #endif /* MAC */ 431 knlist_destroy(&d->bd_sel.si_note); 432 bpf_freed(d); 433 dev->si_drv1 = NULL; 434 free(d, M_BPF); 435 436 return (0); 437 } 438 439 440 /* 441 * Rotate the packet buffers in descriptor d. Move the store buffer 442 * into the hold slot, and the free buffer into the store slot. 443 * Zero the length of the new store buffer. 444 */ 445 #define ROTATE_BUFFERS(d) \ 446 (d)->bd_hbuf = (d)->bd_sbuf; \ 447 (d)->bd_hlen = (d)->bd_slen; \ 448 (d)->bd_sbuf = (d)->bd_fbuf; \ 449 (d)->bd_slen = 0; \ 450 (d)->bd_fbuf = NULL; 451 /* 452 * bpfread - read next chunk of packets from buffers 453 */ 454 static int 455 bpfread(struct cdev *dev, struct uio *uio, int ioflag) 456 { 457 struct bpf_d *d = dev->si_drv1; 458 int timed_out; 459 int error; 460 461 /* 462 * Restrict application to use a buffer the same size as 463 * as kernel buffers. 464 */ 465 if (uio->uio_resid != d->bd_bufsize) 466 return (EINVAL); 467 468 BPFD_LOCK(d); 469 d->bd_pid = curthread->td_proc->p_pid; 470 if (d->bd_state == BPF_WAITING) 471 callout_stop(&d->bd_callout); 472 timed_out = (d->bd_state == BPF_TIMED_OUT); 473 d->bd_state = BPF_IDLE; 474 /* 475 * If the hold buffer is empty, then do a timed sleep, which 476 * ends when the timeout expires or when enough packets 477 * have arrived to fill the store buffer. 478 */ 479 while (d->bd_hbuf == NULL) { 480 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 481 /* 482 * A packet(s) either arrived since the previous 483 * read or arrived while we were asleep. 484 * Rotate the buffers and return what's here. 485 */ 486 ROTATE_BUFFERS(d); 487 break; 488 } 489 490 /* 491 * No data is available, check to see if the bpf device 492 * is still pointed at a real interface. If not, return 493 * ENXIO so that the userland process knows to rebind 494 * it before using it again. 495 */ 496 if (d->bd_bif == NULL) { 497 BPFD_UNLOCK(d); 498 return (ENXIO); 499 } 500 501 if (ioflag & O_NONBLOCK) { 502 BPFD_UNLOCK(d); 503 return (EWOULDBLOCK); 504 } 505 error = msleep(d, &d->bd_mtx, PRINET|PCATCH, 506 "bpf", d->bd_rtout); 507 if (error == EINTR || error == ERESTART) { 508 BPFD_UNLOCK(d); 509 return (error); 510 } 511 if (error == EWOULDBLOCK) { 512 /* 513 * On a timeout, return what's in the buffer, 514 * which may be nothing. If there is something 515 * in the store buffer, we can rotate the buffers. 516 */ 517 if (d->bd_hbuf) 518 /* 519 * We filled up the buffer in between 520 * getting the timeout and arriving 521 * here, so we don't need to rotate. 522 */ 523 break; 524 525 if (d->bd_slen == 0) { 526 BPFD_UNLOCK(d); 527 return (0); 528 } 529 ROTATE_BUFFERS(d); 530 break; 531 } 532 } 533 /* 534 * At this point, we know we have something in the hold slot. 535 */ 536 BPFD_UNLOCK(d); 537 538 /* 539 * Move data from hold buffer into user space. 540 * We know the entire buffer is transferred since 541 * we checked above that the read buffer is bpf_bufsize bytes. 542 */ 543 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 544 545 BPFD_LOCK(d); 546 d->bd_fbuf = d->bd_hbuf; 547 d->bd_hbuf = NULL; 548 d->bd_hlen = 0; 549 BPFD_UNLOCK(d); 550 551 return (error); 552 } 553 554 555 /* 556 * If there are processes sleeping on this descriptor, wake them up. 557 */ 558 static __inline void 559 bpf_wakeup(struct bpf_d *d) 560 { 561 562 BPFD_LOCK_ASSERT(d); 563 if (d->bd_state == BPF_WAITING) { 564 callout_stop(&d->bd_callout); 565 d->bd_state = BPF_IDLE; 566 } 567 wakeup(d); 568 if (d->bd_async && d->bd_sig && d->bd_sigio) 569 pgsigio(&d->bd_sigio, d->bd_sig, 0); 570 571 selwakeuppri(&d->bd_sel, PRINET); 572 KNOTE_LOCKED(&d->bd_sel.si_note, 0); 573 } 574 575 static void 576 bpf_timed_out(void *arg) 577 { 578 struct bpf_d *d = (struct bpf_d *)arg; 579 580 BPFD_LOCK(d); 581 if (d->bd_state == BPF_WAITING) { 582 d->bd_state = BPF_TIMED_OUT; 583 if (d->bd_slen != 0) 584 bpf_wakeup(d); 585 } 586 BPFD_UNLOCK(d); 587 } 588 589 static int 590 bpfwrite(struct cdev *dev, struct uio *uio, int ioflag) 591 { 592 struct bpf_d *d = dev->si_drv1; 593 struct ifnet *ifp; 594 struct mbuf *m; 595 int error; 596 struct sockaddr dst; 597 598 d->bd_pid = curthread->td_proc->p_pid; 599 if (d->bd_bif == NULL) 600 return (ENXIO); 601 602 ifp = d->bd_bif->bif_ifp; 603 604 if ((ifp->if_flags & IFF_UP) == 0) 605 return (ENETDOWN); 606 607 if (uio->uio_resid == 0) 608 return (0); 609 610 bzero(&dst, sizeof(dst)); 611 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp, 612 &m, &dst, d->bd_wfilter); 613 if (error) 614 return (error); 615 616 if (d->bd_hdrcmplt) 617 dst.sa_family = pseudo_AF_HDRCMPLT; 618 619 #ifdef MAC 620 BPFD_LOCK(d); 621 mac_create_mbuf_from_bpfdesc(d, m); 622 BPFD_UNLOCK(d); 623 #endif 624 NET_LOCK_GIANT(); 625 error = (*ifp->if_output)(ifp, m, &dst, NULL); 626 NET_UNLOCK_GIANT(); 627 /* 628 * The driver frees the mbuf. 629 */ 630 return (error); 631 } 632 633 /* 634 * Reset a descriptor by flushing its packet buffer and clearing the 635 * receive and drop counts. 636 */ 637 static void 638 reset_d(struct bpf_d *d) 639 { 640 641 mtx_assert(&d->bd_mtx, MA_OWNED); 642 if (d->bd_hbuf) { 643 /* Free the hold buffer. */ 644 d->bd_fbuf = d->bd_hbuf; 645 d->bd_hbuf = NULL; 646 } 647 d->bd_slen = 0; 648 d->bd_hlen = 0; 649 d->bd_rcount = 0; 650 d->bd_dcount = 0; 651 d->bd_fcount = 0; 652 } 653 654 /* 655 * FIONREAD Check for read packet available. 656 * SIOCGIFADDR Get interface address - convenient hook to driver. 657 * BIOCGBLEN Get buffer len [for read()]. 658 * BIOCSETF Set ethernet read filter. 659 * BIOCSETWF Set ethernet write filter. 660 * BIOCFLUSH Flush read packet buffer. 661 * BIOCPROMISC Put interface into promiscuous mode. 662 * BIOCGDLT Get link layer type. 663 * BIOCGETIF Get interface name. 664 * BIOCSETIF Set interface. 665 * BIOCSRTIMEOUT Set read timeout. 666 * BIOCGRTIMEOUT Get read timeout. 667 * BIOCGSTATS Get packet stats. 668 * BIOCIMMEDIATE Set immediate mode. 669 * BIOCVERSION Get filter language version. 670 * BIOCGHDRCMPLT Get "header already complete" flag 671 * BIOCSHDRCMPLT Set "header already complete" flag 672 * BIOCGSEESENT Get "see packets sent" flag 673 * BIOCSSEESENT Set "see packets sent" flag 674 * BIOCLOCK Set "locked" flag 675 */ 676 /* ARGSUSED */ 677 static int 678 bpfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, 679 struct thread *td) 680 { 681 struct bpf_d *d = dev->si_drv1; 682 int error = 0; 683 684 /* 685 * Refresh PID associated with this descriptor. 686 */ 687 d->bd_pid = td->td_proc->p_pid; 688 BPFD_LOCK(d); 689 if (d->bd_state == BPF_WAITING) 690 callout_stop(&d->bd_callout); 691 d->bd_state = BPF_IDLE; 692 BPFD_UNLOCK(d); 693 694 if (d->bd_locked == 1) { 695 switch (cmd) { 696 case BIOCGBLEN: 697 case BIOCFLUSH: 698 case BIOCGDLT: 699 case BIOCGDLTLIST: 700 case BIOCGETIF: 701 case BIOCGRTIMEOUT: 702 case BIOCGSTATS: 703 case BIOCVERSION: 704 case BIOCGRSIG: 705 case BIOCGHDRCMPLT: 706 case FIONREAD: 707 case BIOCLOCK: 708 case BIOCSRTIMEOUT: 709 case BIOCIMMEDIATE: 710 case TIOCGPGRP: 711 break; 712 default: 713 return (EPERM); 714 } 715 } 716 switch (cmd) { 717 718 default: 719 error = EINVAL; 720 break; 721 722 /* 723 * Check for read packet available. 724 */ 725 case FIONREAD: 726 { 727 int n; 728 729 BPFD_LOCK(d); 730 n = d->bd_slen; 731 if (d->bd_hbuf) 732 n += d->bd_hlen; 733 BPFD_UNLOCK(d); 734 735 *(int *)addr = n; 736 break; 737 } 738 739 case SIOCGIFADDR: 740 { 741 struct ifnet *ifp; 742 743 if (d->bd_bif == NULL) 744 error = EINVAL; 745 else { 746 ifp = d->bd_bif->bif_ifp; 747 error = (*ifp->if_ioctl)(ifp, cmd, addr); 748 } 749 break; 750 } 751 752 /* 753 * Get buffer len [for read()]. 754 */ 755 case BIOCGBLEN: 756 *(u_int *)addr = d->bd_bufsize; 757 break; 758 759 /* 760 * Set buffer length. 761 */ 762 case BIOCSBLEN: 763 if (d->bd_bif != NULL) 764 error = EINVAL; 765 else { 766 u_int size = *(u_int *)addr; 767 768 if (size > bpf_maxbufsize) 769 *(u_int *)addr = size = bpf_maxbufsize; 770 else if (size < BPF_MINBUFSIZE) 771 *(u_int *)addr = size = BPF_MINBUFSIZE; 772 d->bd_bufsize = size; 773 } 774 break; 775 776 /* 777 * Set link layer read filter. 778 */ 779 case BIOCSETF: 780 case BIOCSETWF: 781 error = bpf_setf(d, (struct bpf_program *)addr, cmd); 782 break; 783 784 /* 785 * Flush read packet buffer. 786 */ 787 case BIOCFLUSH: 788 BPFD_LOCK(d); 789 reset_d(d); 790 BPFD_UNLOCK(d); 791 break; 792 793 /* 794 * Put interface into promiscuous mode. 795 */ 796 case BIOCPROMISC: 797 if (d->bd_bif == NULL) { 798 /* 799 * No interface attached yet. 800 */ 801 error = EINVAL; 802 break; 803 } 804 if (d->bd_promisc == 0) { 805 mtx_lock(&Giant); 806 error = ifpromisc(d->bd_bif->bif_ifp, 1); 807 mtx_unlock(&Giant); 808 if (error == 0) 809 d->bd_promisc = 1; 810 } 811 break; 812 813 /* 814 * Get current data link type. 815 */ 816 case BIOCGDLT: 817 if (d->bd_bif == NULL) 818 error = EINVAL; 819 else 820 *(u_int *)addr = d->bd_bif->bif_dlt; 821 break; 822 823 /* 824 * Get a list of supported data link types. 825 */ 826 case BIOCGDLTLIST: 827 if (d->bd_bif == NULL) 828 error = EINVAL; 829 else 830 error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); 831 break; 832 833 /* 834 * Set data link type. 835 */ 836 case BIOCSDLT: 837 if (d->bd_bif == NULL) 838 error = EINVAL; 839 else 840 error = bpf_setdlt(d, *(u_int *)addr); 841 break; 842 843 /* 844 * Get interface name. 845 */ 846 case BIOCGETIF: 847 if (d->bd_bif == NULL) 848 error = EINVAL; 849 else { 850 struct ifnet *const ifp = d->bd_bif->bif_ifp; 851 struct ifreq *const ifr = (struct ifreq *)addr; 852 853 strlcpy(ifr->ifr_name, ifp->if_xname, 854 sizeof(ifr->ifr_name)); 855 } 856 break; 857 858 /* 859 * Set interface. 860 */ 861 case BIOCSETIF: 862 error = bpf_setif(d, (struct ifreq *)addr); 863 break; 864 865 /* 866 * Set read timeout. 867 */ 868 case BIOCSRTIMEOUT: 869 { 870 struct timeval *tv = (struct timeval *)addr; 871 872 /* 873 * Subtract 1 tick from tvtohz() since this isn't 874 * a one-shot timer. 875 */ 876 if ((error = itimerfix(tv)) == 0) 877 d->bd_rtout = tvtohz(tv) - 1; 878 break; 879 } 880 881 /* 882 * Get read timeout. 883 */ 884 case BIOCGRTIMEOUT: 885 { 886 struct timeval *tv = (struct timeval *)addr; 887 888 tv->tv_sec = d->bd_rtout / hz; 889 tv->tv_usec = (d->bd_rtout % hz) * tick; 890 break; 891 } 892 893 /* 894 * Get packet stats. 895 */ 896 case BIOCGSTATS: 897 { 898 struct bpf_stat *bs = (struct bpf_stat *)addr; 899 900 bs->bs_recv = d->bd_rcount; 901 bs->bs_drop = d->bd_dcount; 902 break; 903 } 904 905 /* 906 * Set immediate mode. 907 */ 908 case BIOCIMMEDIATE: 909 d->bd_immediate = *(u_int *)addr; 910 break; 911 912 case BIOCVERSION: 913 { 914 struct bpf_version *bv = (struct bpf_version *)addr; 915 916 bv->bv_major = BPF_MAJOR_VERSION; 917 bv->bv_minor = BPF_MINOR_VERSION; 918 break; 919 } 920 921 /* 922 * Get "header already complete" flag 923 */ 924 case BIOCGHDRCMPLT: 925 *(u_int *)addr = d->bd_hdrcmplt; 926 break; 927 928 case BIOCLOCK: 929 d->bd_locked = 1; 930 break; 931 /* 932 * Set "header already complete" flag 933 */ 934 case BIOCSHDRCMPLT: 935 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 936 break; 937 938 /* 939 * Get "see sent packets" flag 940 */ 941 case BIOCGSEESENT: 942 *(u_int *)addr = d->bd_seesent; 943 break; 944 945 /* 946 * Set "see sent packets" flag 947 */ 948 case BIOCSSEESENT: 949 d->bd_seesent = *(u_int *)addr; 950 break; 951 952 case FIONBIO: /* Non-blocking I/O */ 953 break; 954 955 case FIOASYNC: /* Send signal on receive packets */ 956 d->bd_async = *(int *)addr; 957 break; 958 959 case FIOSETOWN: 960 error = fsetown(*(int *)addr, &d->bd_sigio); 961 break; 962 963 case FIOGETOWN: 964 *(int *)addr = fgetown(&d->bd_sigio); 965 break; 966 967 /* This is deprecated, FIOSETOWN should be used instead. */ 968 case TIOCSPGRP: 969 error = fsetown(-(*(int *)addr), &d->bd_sigio); 970 break; 971 972 /* This is deprecated, FIOGETOWN should be used instead. */ 973 case TIOCGPGRP: 974 *(int *)addr = -fgetown(&d->bd_sigio); 975 break; 976 977 case BIOCSRSIG: /* Set receive signal */ 978 { 979 u_int sig; 980 981 sig = *(u_int *)addr; 982 983 if (sig >= NSIG) 984 error = EINVAL; 985 else 986 d->bd_sig = sig; 987 break; 988 } 989 case BIOCGRSIG: 990 *(u_int *)addr = d->bd_sig; 991 break; 992 } 993 return (error); 994 } 995 996 /* 997 * Set d's packet filter program to fp. If this file already has a filter, 998 * free it and replace it. Returns EINVAL for bogus requests. 999 */ 1000 static int 1001 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd) 1002 { 1003 struct bpf_insn *fcode, *old; 1004 u_int wfilter, flen, size; 1005 1006 if (cmd == BIOCSETWF) { 1007 old = d->bd_wfilter; 1008 wfilter = 1; 1009 } else { 1010 wfilter = 0; 1011 old = d->bd_rfilter; 1012 } 1013 if (fp->bf_insns == NULL) { 1014 if (fp->bf_len != 0) 1015 return (EINVAL); 1016 BPFD_LOCK(d); 1017 if (wfilter) 1018 d->bd_wfilter = NULL; 1019 else 1020 d->bd_rfilter = NULL; 1021 reset_d(d); 1022 BPFD_UNLOCK(d); 1023 if (old != NULL) 1024 free((caddr_t)old, M_BPF); 1025 return (0); 1026 } 1027 flen = fp->bf_len; 1028 if (flen > bpf_maxinsns) 1029 return (EINVAL); 1030 1031 size = flen * sizeof(*fp->bf_insns); 1032 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK); 1033 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 1034 bpf_validate(fcode, (int)flen)) { 1035 BPFD_LOCK(d); 1036 if (wfilter) 1037 d->bd_wfilter = fcode; 1038 else 1039 d->bd_rfilter = fcode; 1040 reset_d(d); 1041 BPFD_UNLOCK(d); 1042 if (old != NULL) 1043 free((caddr_t)old, M_BPF); 1044 1045 return (0); 1046 } 1047 free((caddr_t)fcode, M_BPF); 1048 return (EINVAL); 1049 } 1050 1051 /* 1052 * Detach a file from its current interface (if attached at all) and attach 1053 * to the interface indicated by the name stored in ifr. 1054 * Return an errno or 0. 1055 */ 1056 static int 1057 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 1058 { 1059 struct bpf_if *bp; 1060 int error; 1061 struct ifnet *theywant; 1062 1063 theywant = ifunit(ifr->ifr_name); 1064 if (theywant == NULL || theywant->if_bpf == NULL) 1065 return (ENXIO); 1066 1067 bp = theywant->if_bpf; 1068 /* 1069 * Allocate the packet buffers if we need to. 1070 * If we're already attached to requested interface, 1071 * just flush the buffer. 1072 */ 1073 if (d->bd_sbuf == NULL) { 1074 error = bpf_allocbufs(d); 1075 if (error != 0) 1076 return (error); 1077 } 1078 if (bp != d->bd_bif) { 1079 if (d->bd_bif) 1080 /* 1081 * Detach if attached to something else. 1082 */ 1083 bpf_detachd(d); 1084 1085 bpf_attachd(d, bp); 1086 } 1087 BPFD_LOCK(d); 1088 reset_d(d); 1089 BPFD_UNLOCK(d); 1090 return (0); 1091 } 1092 1093 /* 1094 * Support for select() and poll() system calls 1095 * 1096 * Return true iff the specific operation will not block indefinitely. 1097 * Otherwise, return false but make a note that a selwakeup() must be done. 1098 */ 1099 static int 1100 bpfpoll(struct cdev *dev, int events, struct thread *td) 1101 { 1102 struct bpf_d *d; 1103 int revents; 1104 1105 d = dev->si_drv1; 1106 if (d->bd_bif == NULL) 1107 return (ENXIO); 1108 1109 /* 1110 * Refresh PID associated with this descriptor. 1111 */ 1112 d->bd_pid = td->td_proc->p_pid; 1113 revents = events & (POLLOUT | POLLWRNORM); 1114 BPFD_LOCK(d); 1115 if (events & (POLLIN | POLLRDNORM)) { 1116 if (bpf_ready(d)) 1117 revents |= events & (POLLIN | POLLRDNORM); 1118 else { 1119 selrecord(td, &d->bd_sel); 1120 /* Start the read timeout if necessary. */ 1121 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1122 callout_reset(&d->bd_callout, d->bd_rtout, 1123 bpf_timed_out, d); 1124 d->bd_state = BPF_WAITING; 1125 } 1126 } 1127 } 1128 BPFD_UNLOCK(d); 1129 return (revents); 1130 } 1131 1132 /* 1133 * Support for kevent() system call. Register EVFILT_READ filters and 1134 * reject all others. 1135 */ 1136 int 1137 bpfkqfilter(struct cdev *dev, struct knote *kn) 1138 { 1139 struct bpf_d *d = (struct bpf_d *)dev->si_drv1; 1140 1141 if (kn->kn_filter != EVFILT_READ) 1142 return (1); 1143 1144 /* 1145 * Refresh PID associated with this descriptor. 1146 */ 1147 d->bd_pid = curthread->td_proc->p_pid; 1148 kn->kn_fop = &bpfread_filtops; 1149 kn->kn_hook = d; 1150 knlist_add(&d->bd_sel.si_note, kn, 0); 1151 1152 return (0); 1153 } 1154 1155 static void 1156 filt_bpfdetach(struct knote *kn) 1157 { 1158 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1159 1160 knlist_remove(&d->bd_sel.si_note, kn, 0); 1161 } 1162 1163 static int 1164 filt_bpfread(struct knote *kn, long hint) 1165 { 1166 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1167 int ready; 1168 1169 BPFD_LOCK_ASSERT(d); 1170 ready = bpf_ready(d); 1171 if (ready) { 1172 kn->kn_data = d->bd_slen; 1173 if (d->bd_hbuf) 1174 kn->kn_data += d->bd_hlen; 1175 } 1176 else if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1177 callout_reset(&d->bd_callout, d->bd_rtout, 1178 bpf_timed_out, d); 1179 d->bd_state = BPF_WAITING; 1180 } 1181 1182 return (ready); 1183 } 1184 1185 /* 1186 * Incoming linkage from device drivers. Process the packet pkt, of length 1187 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1188 * by each process' filter, and if accepted, stashed into the corresponding 1189 * buffer. 1190 */ 1191 void 1192 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1193 { 1194 struct bpf_d *d; 1195 u_int slen; 1196 int gottime; 1197 struct timeval tv; 1198 1199 gottime = 0; 1200 BPFIF_LOCK(bp); 1201 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1202 BPFD_LOCK(d); 1203 ++d->bd_rcount; 1204 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen); 1205 if (slen != 0) { 1206 d->bd_fcount++; 1207 if (!gottime) { 1208 microtime(&tv); 1209 gottime = 1; 1210 } 1211 #ifdef MAC 1212 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1213 #endif 1214 catchpacket(d, pkt, pktlen, slen, bcopy, &tv); 1215 } 1216 BPFD_UNLOCK(d); 1217 } 1218 BPFIF_UNLOCK(bp); 1219 } 1220 1221 /* 1222 * Copy data from an mbuf chain into a buffer. This code is derived 1223 * from m_copydata in sys/uipc_mbuf.c. 1224 */ 1225 static void 1226 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len) 1227 { 1228 const struct mbuf *m; 1229 u_int count; 1230 u_char *dst; 1231 1232 m = src_arg; 1233 dst = dst_arg; 1234 while (len > 0) { 1235 if (m == NULL) 1236 panic("bpf_mcopy"); 1237 count = min(m->m_len, len); 1238 bcopy(mtod(m, void *), dst, count); 1239 m = m->m_next; 1240 dst += count; 1241 len -= count; 1242 } 1243 } 1244 1245 /* 1246 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1247 */ 1248 void 1249 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1250 { 1251 struct bpf_d *d; 1252 u_int pktlen, slen; 1253 int gottime; 1254 struct timeval tv; 1255 1256 gottime = 0; 1257 1258 pktlen = m_length(m, NULL); 1259 1260 BPFIF_LOCK(bp); 1261 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1262 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) 1263 continue; 1264 BPFD_LOCK(d); 1265 ++d->bd_rcount; 1266 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0); 1267 if (slen != 0) { 1268 d->bd_fcount++; 1269 if (!gottime) { 1270 microtime(&tv); 1271 gottime = 1; 1272 } 1273 #ifdef MAC 1274 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1275 #endif 1276 catchpacket(d, (u_char *)m, pktlen, slen, 1277 bpf_mcopy, &tv); 1278 } 1279 BPFD_UNLOCK(d); 1280 } 1281 BPFIF_UNLOCK(bp); 1282 } 1283 1284 /* 1285 * Incoming linkage from device drivers, when packet is in 1286 * an mbuf chain and to be prepended by a contiguous header. 1287 */ 1288 void 1289 bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) 1290 { 1291 struct mbuf mb; 1292 struct bpf_d *d; 1293 u_int pktlen, slen; 1294 int gottime; 1295 struct timeval tv; 1296 1297 gottime = 0; 1298 1299 pktlen = m_length(m, NULL); 1300 /* 1301 * Craft on-stack mbuf suitable for passing to bpf_filter. 1302 * Note that we cut corners here; we only setup what's 1303 * absolutely needed--this mbuf should never go anywhere else. 1304 */ 1305 mb.m_next = m; 1306 mb.m_data = data; 1307 mb.m_len = dlen; 1308 pktlen += dlen; 1309 1310 BPFIF_LOCK(bp); 1311 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1312 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) 1313 continue; 1314 BPFD_LOCK(d); 1315 ++d->bd_rcount; 1316 slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0); 1317 if (slen != 0) { 1318 d->bd_fcount++; 1319 if (!gottime) { 1320 microtime(&tv); 1321 gottime = 1; 1322 } 1323 #ifdef MAC 1324 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1325 #endif 1326 catchpacket(d, (u_char *)&mb, pktlen, slen, 1327 bpf_mcopy, &tv); 1328 } 1329 BPFD_UNLOCK(d); 1330 } 1331 BPFIF_UNLOCK(bp); 1332 } 1333 1334 /* 1335 * Move the packet data from interface memory (pkt) into the 1336 * store buffer. "cpfn" is the routine called to do the actual data 1337 * transfer. bcopy is passed in to copy contiguous chunks, while 1338 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1339 * pkt is really an mbuf. 1340 */ 1341 static void 1342 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1343 void (*cpfn)(const void *, void *, size_t), struct timeval *tv) 1344 { 1345 struct bpf_hdr *hp; 1346 int totlen, curlen; 1347 int hdrlen = d->bd_bif->bif_hdrlen; 1348 int do_wakeup = 0; 1349 1350 BPFD_LOCK_ASSERT(d); 1351 /* 1352 * Figure out how many bytes to move. If the packet is 1353 * greater or equal to the snapshot length, transfer that 1354 * much. Otherwise, transfer the whole packet (unless 1355 * we hit the buffer size limit). 1356 */ 1357 totlen = hdrlen + min(snaplen, pktlen); 1358 if (totlen > d->bd_bufsize) 1359 totlen = d->bd_bufsize; 1360 1361 /* 1362 * Round up the end of the previous packet to the next longword. 1363 */ 1364 curlen = BPF_WORDALIGN(d->bd_slen); 1365 if (curlen + totlen > d->bd_bufsize) { 1366 /* 1367 * This packet will overflow the storage buffer. 1368 * Rotate the buffers if we can, then wakeup any 1369 * pending reads. 1370 */ 1371 if (d->bd_fbuf == NULL) { 1372 /* 1373 * We haven't completed the previous read yet, 1374 * so drop the packet. 1375 */ 1376 ++d->bd_dcount; 1377 return; 1378 } 1379 ROTATE_BUFFERS(d); 1380 do_wakeup = 1; 1381 curlen = 0; 1382 } 1383 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) 1384 /* 1385 * Immediate mode is set, or the read timeout has 1386 * already expired during a select call. A packet 1387 * arrived, so the reader should be woken up. 1388 */ 1389 do_wakeup = 1; 1390 1391 /* 1392 * Append the bpf header. 1393 */ 1394 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1395 hp->bh_tstamp = *tv; 1396 hp->bh_datalen = pktlen; 1397 hp->bh_hdrlen = hdrlen; 1398 /* 1399 * Copy the packet data into the store buffer and update its length. 1400 */ 1401 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1402 d->bd_slen = curlen + totlen; 1403 1404 if (do_wakeup) 1405 bpf_wakeup(d); 1406 } 1407 1408 /* 1409 * Initialize all nonzero fields of a descriptor. 1410 */ 1411 static int 1412 bpf_allocbufs(struct bpf_d *d) 1413 { 1414 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1415 if (d->bd_fbuf == NULL) 1416 return (ENOBUFS); 1417 1418 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1419 if (d->bd_sbuf == NULL) { 1420 free(d->bd_fbuf, M_BPF); 1421 return (ENOBUFS); 1422 } 1423 d->bd_slen = 0; 1424 d->bd_hlen = 0; 1425 return (0); 1426 } 1427 1428 /* 1429 * Free buffers currently in use by a descriptor. 1430 * Called on close. 1431 */ 1432 static void 1433 bpf_freed(struct bpf_d *d) 1434 { 1435 /* 1436 * We don't need to lock out interrupts since this descriptor has 1437 * been detached from its interface and it yet hasn't been marked 1438 * free. 1439 */ 1440 if (d->bd_sbuf != NULL) { 1441 free(d->bd_sbuf, M_BPF); 1442 if (d->bd_hbuf != NULL) 1443 free(d->bd_hbuf, M_BPF); 1444 if (d->bd_fbuf != NULL) 1445 free(d->bd_fbuf, M_BPF); 1446 } 1447 if (d->bd_rfilter) 1448 free((caddr_t)d->bd_rfilter, M_BPF); 1449 if (d->bd_wfilter) 1450 free((caddr_t)d->bd_wfilter, M_BPF); 1451 mtx_destroy(&d->bd_mtx); 1452 } 1453 1454 /* 1455 * Attach an interface to bpf. dlt is the link layer type; hdrlen is the 1456 * fixed size of the link header (variable length headers not yet supported). 1457 */ 1458 void 1459 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1460 { 1461 1462 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); 1463 } 1464 1465 /* 1466 * Attach an interface to bpf. ifp is a pointer to the structure 1467 * defining the interface to be attached, dlt is the link layer type, 1468 * and hdrlen is the fixed size of the link header (variable length 1469 * headers are not yet supporrted). 1470 */ 1471 void 1472 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1473 { 1474 struct bpf_if *bp; 1475 1476 bp = malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO); 1477 if (bp == NULL) 1478 panic("bpfattach"); 1479 1480 LIST_INIT(&bp->bif_dlist); 1481 bp->bif_ifp = ifp; 1482 bp->bif_dlt = dlt; 1483 mtx_init(&bp->bif_mtx, "bpf interface lock", NULL, MTX_DEF); 1484 KASSERT(*driverp == NULL, ("bpfattach2: driverp already initialized")); 1485 *driverp = bp; 1486 1487 mtx_lock(&bpf_mtx); 1488 LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next); 1489 mtx_unlock(&bpf_mtx); 1490 1491 /* 1492 * Compute the length of the bpf header. This is not necessarily 1493 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1494 * that the network layer header begins on a longword boundary (for 1495 * performance reasons and to alleviate alignment restrictions). 1496 */ 1497 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1498 1499 if (bootverbose) 1500 if_printf(ifp, "bpf attached\n"); 1501 } 1502 1503 /* 1504 * Detach bpf from an interface. This involves detaching each descriptor 1505 * associated with the interface, and leaving bd_bif NULL. Notify each 1506 * descriptor as it's detached so that any sleepers wake up and get 1507 * ENXIO. 1508 */ 1509 void 1510 bpfdetach(struct ifnet *ifp) 1511 { 1512 struct bpf_if *bp; 1513 struct bpf_d *d; 1514 1515 /* Locate BPF interface information */ 1516 mtx_lock(&bpf_mtx); 1517 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1518 if (ifp == bp->bif_ifp) 1519 break; 1520 } 1521 1522 /* Interface wasn't attached */ 1523 if ((bp == NULL) || (bp->bif_ifp == NULL)) { 1524 mtx_unlock(&bpf_mtx); 1525 printf("bpfdetach: %s was not attached\n", ifp->if_xname); 1526 return; 1527 } 1528 1529 LIST_REMOVE(bp, bif_next); 1530 mtx_unlock(&bpf_mtx); 1531 1532 while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) { 1533 bpf_detachd(d); 1534 BPFD_LOCK(d); 1535 bpf_wakeup(d); 1536 BPFD_UNLOCK(d); 1537 } 1538 1539 mtx_destroy(&bp->bif_mtx); 1540 free(bp, M_BPF); 1541 } 1542 1543 /* 1544 * Get a list of available data link type of the interface. 1545 */ 1546 static int 1547 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 1548 { 1549 int n, error; 1550 struct ifnet *ifp; 1551 struct bpf_if *bp; 1552 1553 ifp = d->bd_bif->bif_ifp; 1554 n = 0; 1555 error = 0; 1556 mtx_lock(&bpf_mtx); 1557 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1558 if (bp->bif_ifp != ifp) 1559 continue; 1560 if (bfl->bfl_list != NULL) { 1561 if (n >= bfl->bfl_len) { 1562 mtx_unlock(&bpf_mtx); 1563 return (ENOMEM); 1564 } 1565 error = copyout(&bp->bif_dlt, 1566 bfl->bfl_list + n, sizeof(u_int)); 1567 } 1568 n++; 1569 } 1570 mtx_unlock(&bpf_mtx); 1571 bfl->bfl_len = n; 1572 return (error); 1573 } 1574 1575 /* 1576 * Set the data link type of a BPF instance. 1577 */ 1578 static int 1579 bpf_setdlt(struct bpf_d *d, u_int dlt) 1580 { 1581 int error, opromisc; 1582 struct ifnet *ifp; 1583 struct bpf_if *bp; 1584 1585 if (d->bd_bif->bif_dlt == dlt) 1586 return (0); 1587 ifp = d->bd_bif->bif_ifp; 1588 mtx_lock(&bpf_mtx); 1589 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1590 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1591 break; 1592 } 1593 mtx_unlock(&bpf_mtx); 1594 if (bp != NULL) { 1595 opromisc = d->bd_promisc; 1596 bpf_detachd(d); 1597 bpf_attachd(d, bp); 1598 BPFD_LOCK(d); 1599 reset_d(d); 1600 BPFD_UNLOCK(d); 1601 if (opromisc) { 1602 error = ifpromisc(bp->bif_ifp, 1); 1603 if (error) 1604 if_printf(bp->bif_ifp, 1605 "bpf_setdlt: ifpromisc failed (%d)\n", 1606 error); 1607 else 1608 d->bd_promisc = 1; 1609 } 1610 } 1611 return (bp == NULL ? EINVAL : 0); 1612 } 1613 1614 static void 1615 bpf_clone(void *arg, struct ucred *cred, char *name, int namelen, 1616 struct cdev **dev) 1617 { 1618 int u; 1619 1620 if (*dev != NULL) 1621 return; 1622 if (dev_stdclone(name, NULL, "bpf", &u) != 1) 1623 return; 1624 *dev = make_dev(&bpf_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 1625 "bpf%d", u); 1626 dev_ref(*dev); 1627 (*dev)->si_flags |= SI_CHEAPCLONE; 1628 return; 1629 } 1630 1631 static void 1632 bpf_drvinit(void *unused) 1633 { 1634 1635 mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF); 1636 LIST_INIT(&bpf_iflist); 1637 EVENTHANDLER_REGISTER(dev_clone, bpf_clone, 0, 1000); 1638 } 1639 1640 static void 1641 bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd) 1642 { 1643 1644 bzero(d, sizeof(*d)); 1645 BPFD_LOCK_ASSERT(bd); 1646 d->bd_immediate = bd->bd_immediate; 1647 d->bd_promisc = bd->bd_promisc; 1648 d->bd_hdrcmplt = bd->bd_hdrcmplt; 1649 d->bd_seesent = bd->bd_seesent; 1650 d->bd_async = bd->bd_async; 1651 d->bd_rcount = bd->bd_rcount; 1652 d->bd_dcount = bd->bd_dcount; 1653 d->bd_fcount = bd->bd_fcount; 1654 d->bd_sig = bd->bd_sig; 1655 d->bd_slen = bd->bd_slen; 1656 d->bd_hlen = bd->bd_hlen; 1657 d->bd_bufsize = bd->bd_bufsize; 1658 d->bd_pid = bd->bd_pid; 1659 strlcpy(d->bd_ifname, 1660 bd->bd_bif->bif_ifp->if_xname, IFNAMSIZ); 1661 strlcpy(d->bd_pcomm, bd->bd_pcomm, MAXCOMLEN); 1662 d->bd_locked = bd->bd_locked; 1663 } 1664 1665 static int 1666 bpf_stats_sysctl(SYSCTL_HANDLER_ARGS) 1667 { 1668 struct xbpf_d *xbdbuf, *xbd; 1669 int index, error; 1670 struct bpf_if *bp; 1671 struct bpf_d *bd; 1672 1673 /* 1674 * XXX This is not technically correct. It is possible for non 1675 * privileged users to open bpf devices. It would make sense 1676 * if the users who opened the devices were able to retrieve 1677 * the statistics for them, too. 1678 */ 1679 error = suser(req->td); 1680 if (error) 1681 return (error); 1682 if (req->oldptr == NULL) 1683 return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd))); 1684 if (bpf_bpfd_cnt == 0) 1685 return (SYSCTL_OUT(req, 0, 0)); 1686 xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK); 1687 mtx_lock(&bpf_mtx); 1688 if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) { 1689 mtx_unlock(&bpf_mtx); 1690 free(xbdbuf, M_BPF); 1691 return (ENOMEM); 1692 } 1693 index = 0; 1694 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1695 BPFIF_LOCK(bp); 1696 LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { 1697 xbd = &xbdbuf[index++]; 1698 BPFD_LOCK(bd); 1699 bpfstats_fill_xbpf(xbd, bd); 1700 BPFD_UNLOCK(bd); 1701 } 1702 BPFIF_UNLOCK(bp); 1703 } 1704 mtx_unlock(&bpf_mtx); 1705 error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd)); 1706 free(xbdbuf, M_BPF); 1707 return (error); 1708 } 1709 1710 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,bpf_drvinit,NULL) 1711 1712 #else /* !DEV_BPF && !NETGRAPH_BPF */ 1713 /* 1714 * NOP stubs to allow bpf-using drivers to load and function. 1715 * 1716 * A 'better' implementation would allow the core bpf functionality 1717 * to be loaded at runtime. 1718 */ 1719 static struct bpf_if bp_null; 1720 1721 void 1722 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1723 { 1724 } 1725 1726 void 1727 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1728 { 1729 } 1730 1731 void 1732 bpf_mtap2(struct bpf_if *bp, void *d, u_int l, struct mbuf *m) 1733 { 1734 } 1735 1736 void 1737 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1738 { 1739 1740 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); 1741 } 1742 1743 void 1744 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1745 { 1746 1747 *driverp = &bp_null; 1748 } 1749 1750 void 1751 bpfdetach(struct ifnet *ifp) 1752 { 1753 } 1754 1755 u_int 1756 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen) 1757 { 1758 return -1; /* "no filter" behaviour */ 1759 } 1760 1761 int 1762 bpf_validate(const struct bpf_insn *f, int len) 1763 { 1764 return 0; /* false */ 1765 } 1766 1767 #endif /* !DEV_BPF && !NETGRAPH_BPF */ 1768 1769 /* 1770 * ABI compatibility hacks. Older drivers check if_bpf against NULL 1771 * to see if there are active listeners. In the new ABI, if_bpf is 1772 * always non-NULL, so bpf_*tap() are always invoked. We check for 1773 * listeners in these wrappers and call the real functions if needed. 1774 */ 1775 #undef bpf_tap 1776 #undef bpf_mtap 1777 #undef bpf_mtap2 1778 1779 void bpf_tap(struct bpf_if *, u_char *, u_int); 1780 void bpf_mtap(struct bpf_if *, struct mbuf *); 1781 void bpf_mtap2(struct bpf_if *, void *, u_int, struct mbuf *); 1782 1783 void 1784 bpf_tap(bp, pkt, pktlen) 1785 struct bpf_if *bp; 1786 u_char *pkt; 1787 u_int pktlen; 1788 { 1789 1790 if (bpf_peers_present(bp)) 1791 bpf_tap_new(bp, pkt, pktlen); 1792 } 1793 1794 void 1795 bpf_mtap(bp, m) 1796 struct bpf_if *bp; 1797 struct mbuf *m; 1798 { 1799 1800 if (bpf_peers_present(bp)) 1801 bpf_mtap_new(bp, m); 1802 } 1803 1804 void 1805 bpf_mtap2(bp, d, l, m) 1806 struct bpf_if *bp; 1807 void *d; 1808 u_int l; 1809 struct mbuf *m; 1810 { 1811 1812 if (bpf_peers_present(bp)) 1813 bpf_mtap2_new(bp, d, l, m); 1814 }
Cache object: 0ca62f69d3de97457e7186d7b8acdbf0
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