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 * $FreeBSD$ 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/malloc.h> 49 #include <sys/mbuf.h> 50 #include <sys/time.h> 51 #include <sys/priv.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 #ifdef BPF_JITTER 69 #include <net/bpf_jitter.h> 70 #endif 71 #include <net/bpfdesc.h> 72 73 #include <netinet/in.h> 74 #include <netinet/if_ether.h> 75 #include <sys/kernel.h> 76 #include <sys/sysctl.h> 77 78 #include <net80211/ieee80211_freebsd.h> 79 80 #include <security/mac/mac_framework.h> 81 82 static MALLOC_DEFINE(M_BPF, "BPF", "BPF data"); 83 84 #if defined(DEV_BPF) || defined(NETGRAPH_BPF) 85 86 #define PRINET 26 /* interruptible */ 87 88 #define M_SKIP_BPF M_SKIP_FIREWALL 89 90 /* 91 * bpf_iflist is a list of BPF interface structures, each corresponding to a 92 * specific DLT. The same network interface might have several BPF interface 93 * structures registered by different layers in the stack (i.e., 802.11 94 * frames, ethernet frames, etc). 95 */ 96 static LIST_HEAD(, bpf_if) bpf_iflist; 97 static struct mtx bpf_mtx; /* bpf global lock */ 98 static int bpf_bpfd_cnt; 99 100 static void bpf_allocbufs(struct bpf_d *); 101 static void bpf_attachd(struct bpf_d *, struct bpf_if *); 102 static void bpf_detachd(struct bpf_d *); 103 static void bpf_freed(struct bpf_d *); 104 static void bpf_mcopy(const void *, void *, size_t); 105 static int bpf_movein(struct uio *, int, struct ifnet *, struct mbuf **, 106 struct sockaddr *, int *, struct bpf_insn *); 107 static int bpf_setif(struct bpf_d *, struct ifreq *); 108 static void bpf_timed_out(void *); 109 static __inline void 110 bpf_wakeup(struct bpf_d *); 111 static void catchpacket(struct bpf_d *, u_char *, u_int, 112 u_int, void (*)(const void *, void *, size_t), 113 struct timeval *); 114 static void reset_d(struct bpf_d *); 115 static int bpf_setf(struct bpf_d *, struct bpf_program *, u_long cmd); 116 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 117 static int bpf_setdlt(struct bpf_d *, u_int); 118 static void filt_bpfdetach(struct knote *); 119 static int filt_bpfread(struct knote *, long); 120 static void bpf_drvinit(void *); 121 static void bpf_clone(void *, struct ucred *, char *, int, struct cdev **); 122 static int bpf_stats_sysctl(SYSCTL_HANDLER_ARGS); 123 124 SYSCTL_NODE(_net, OID_AUTO, bpf, CTLFLAG_RW, 0, "bpf sysctl"); 125 static int bpf_bufsize = 4096; 126 SYSCTL_INT(_net_bpf, OID_AUTO, bufsize, CTLFLAG_RW, 127 &bpf_bufsize, 0, "Default bpf buffer size"); 128 static int bpf_maxbufsize = BPF_MAXBUFSIZE; 129 SYSCTL_INT(_net_bpf, OID_AUTO, maxbufsize, CTLFLAG_RW, 130 &bpf_maxbufsize, 0, "Maximum bpf buffer size"); 131 static int bpf_maxinsns = BPF_MAXINSNS; 132 SYSCTL_INT(_net_bpf, OID_AUTO, maxinsns, CTLFLAG_RW, 133 &bpf_maxinsns, 0, "Maximum bpf program instructions"); 134 SYSCTL_NODE(_net_bpf, OID_AUTO, stats, CTLFLAG_RW, 135 bpf_stats_sysctl, "bpf statistics portal"); 136 137 static d_open_t bpfopen; 138 static d_close_t bpfclose; 139 static d_read_t bpfread; 140 static d_write_t bpfwrite; 141 static d_ioctl_t bpfioctl; 142 static d_poll_t bpfpoll; 143 static d_kqfilter_t bpfkqfilter; 144 145 static struct cdevsw bpf_cdevsw = { 146 .d_version = D_VERSION, 147 .d_open = bpfopen, 148 .d_close = bpfclose, 149 .d_read = bpfread, 150 .d_write = bpfwrite, 151 .d_ioctl = bpfioctl, 152 .d_poll = bpfpoll, 153 .d_name = "bpf", 154 .d_kqfilter = bpfkqfilter, 155 }; 156 157 static struct filterops bpfread_filtops = 158 { 1, NULL, filt_bpfdetach, filt_bpfread }; 159 160 static int 161 bpf_movein(struct uio *uio, int linktype, struct ifnet *ifp, struct mbuf **mp, 162 struct sockaddr *sockp, int *hdrlen, struct bpf_insn *wfilter) 163 { 164 const struct ieee80211_bpf_params *p; 165 struct ether_header *eh; 166 struct mbuf *m; 167 int error; 168 int len; 169 int hlen; 170 int slen; 171 172 /* 173 * Build a sockaddr based on the data link layer type. 174 * We do this at this level because the ethernet header 175 * is copied directly into the data field of the sockaddr. 176 * In the case of SLIP, there is no header and the packet 177 * is forwarded as is. 178 * Also, we are careful to leave room at the front of the mbuf 179 * for the link level header. 180 */ 181 switch (linktype) { 182 183 case DLT_SLIP: 184 sockp->sa_family = AF_INET; 185 hlen = 0; 186 break; 187 188 case DLT_EN10MB: 189 sockp->sa_family = AF_UNSPEC; 190 /* XXX Would MAXLINKHDR be better? */ 191 hlen = ETHER_HDR_LEN; 192 break; 193 194 case DLT_FDDI: 195 sockp->sa_family = AF_IMPLINK; 196 hlen = 0; 197 break; 198 199 case DLT_RAW: 200 sockp->sa_family = AF_UNSPEC; 201 hlen = 0; 202 break; 203 204 case DLT_NULL: 205 /* 206 * null interface types require a 4 byte pseudo header which 207 * corresponds to the address family of the packet. 208 */ 209 sockp->sa_family = AF_UNSPEC; 210 hlen = 4; 211 break; 212 213 case DLT_ATM_RFC1483: 214 /* 215 * en atm driver requires 4-byte atm pseudo header. 216 * though it isn't standard, vpi:vci needs to be 217 * specified anyway. 218 */ 219 sockp->sa_family = AF_UNSPEC; 220 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */ 221 break; 222 223 case DLT_PPP: 224 sockp->sa_family = AF_UNSPEC; 225 hlen = 4; /* This should match PPP_HDRLEN */ 226 break; 227 228 case DLT_IEEE802_11: /* IEEE 802.11 wireless */ 229 sockp->sa_family = AF_IEEE80211; 230 hlen = 0; 231 break; 232 233 case DLT_IEEE802_11_RADIO: /* IEEE 802.11 wireless w/ phy params */ 234 sockp->sa_family = AF_IEEE80211; 235 sockp->sa_len = 12; /* XXX != 0 */ 236 hlen = sizeof(struct ieee80211_bpf_params); 237 break; 238 239 default: 240 return (EIO); 241 } 242 243 len = uio->uio_resid; 244 245 if (len - hlen > ifp->if_mtu) 246 return (EMSGSIZE); 247 248 if ((unsigned)len > MCLBYTES) 249 return (EIO); 250 251 if (len > MHLEN) { 252 m = m_getcl(M_TRYWAIT, MT_DATA, M_PKTHDR); 253 } else { 254 MGETHDR(m, M_TRYWAIT, MT_DATA); 255 } 256 if (m == NULL) 257 return (ENOBUFS); 258 m->m_pkthdr.len = m->m_len = len; 259 m->m_pkthdr.rcvif = NULL; 260 *mp = m; 261 262 if (m->m_len < hlen) { 263 error = EPERM; 264 goto bad; 265 } 266 267 error = uiomove(mtod(m, u_char *), len, uio); 268 if (error) 269 goto bad; 270 271 slen = bpf_filter(wfilter, mtod(m, u_char *), len, len); 272 if (slen == 0) { 273 error = EPERM; 274 goto bad; 275 } 276 277 /* Check for multicast destination */ 278 switch (linktype) { 279 case DLT_EN10MB: 280 eh = mtod(m, struct ether_header *); 281 if (ETHER_IS_MULTICAST(eh->ether_dhost)) { 282 if (bcmp(ifp->if_broadcastaddr, eh->ether_dhost, 283 ETHER_ADDR_LEN) == 0) 284 m->m_flags |= M_BCAST; 285 else 286 m->m_flags |= M_MCAST; 287 } 288 break; 289 } 290 291 /* 292 * Make room for link header, and copy it to sockaddr 293 */ 294 if (hlen != 0) { 295 if (sockp->sa_family == AF_IEEE80211) { 296 /* 297 * Collect true length from the parameter header 298 * NB: sockp is known to be zero'd so if we do a 299 * short copy unspecified parameters will be 300 * zero. 301 * NB: packet may not be aligned after stripping 302 * bpf params 303 * XXX check ibp_vers 304 */ 305 p = mtod(m, const struct ieee80211_bpf_params *); 306 hlen = p->ibp_len; 307 if (hlen > sizeof(sockp->sa_data)) { 308 error = EINVAL; 309 goto bad; 310 } 311 } 312 bcopy(m->m_data, sockp->sa_data, hlen); 313 } 314 *hdrlen = hlen; 315 316 return (0); 317 bad: 318 m_freem(m); 319 return (error); 320 } 321 322 /* 323 * Attach file to the bpf interface, i.e. make d listen on bp. 324 */ 325 static void 326 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 327 { 328 /* 329 * Point d at bp, and add d to the interface's list of listeners. 330 * Finally, point the driver's bpf cookie at the interface so 331 * it will divert packets to bpf. 332 */ 333 BPFIF_LOCK(bp); 334 d->bd_bif = bp; 335 LIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); 336 337 bpf_bpfd_cnt++; 338 BPFIF_UNLOCK(bp); 339 } 340 341 /* 342 * Detach a file from its interface. 343 */ 344 static void 345 bpf_detachd(struct bpf_d *d) 346 { 347 int error; 348 struct bpf_if *bp; 349 struct ifnet *ifp; 350 351 bp = d->bd_bif; 352 BPFIF_LOCK(bp); 353 BPFD_LOCK(d); 354 ifp = d->bd_bif->bif_ifp; 355 356 /* 357 * Remove d from the interface's descriptor list. 358 */ 359 LIST_REMOVE(d, bd_next); 360 361 bpf_bpfd_cnt--; 362 d->bd_bif = NULL; 363 BPFD_UNLOCK(d); 364 BPFIF_UNLOCK(bp); 365 366 /* 367 * Check if this descriptor had requested promiscuous mode. 368 * If so, turn it off. 369 */ 370 if (d->bd_promisc) { 371 d->bd_promisc = 0; 372 error = ifpromisc(ifp, 0); 373 if (error != 0 && error != ENXIO) { 374 /* 375 * ENXIO can happen if a pccard is unplugged 376 * Something is really wrong if we were able to put 377 * the driver into promiscuous mode, but can't 378 * take it out. 379 */ 380 if_printf(bp->bif_ifp, 381 "bpf_detach: ifpromisc failed (%d)\n", error); 382 } 383 } 384 } 385 386 /* 387 * Open ethernet device. Returns ENXIO for illegal minor device number, 388 * EBUSY if file is open by another process. 389 */ 390 /* ARGSUSED */ 391 static int 392 bpfopen(struct cdev *dev, int flags, int fmt, struct thread *td) 393 { 394 struct bpf_d *d; 395 396 mtx_lock(&bpf_mtx); 397 d = dev->si_drv1; 398 /* 399 * Each minor can be opened by only one process. If the requested 400 * minor is in use, return EBUSY. 401 */ 402 if (d != NULL) { 403 mtx_unlock(&bpf_mtx); 404 return (EBUSY); 405 } 406 dev->si_drv1 = (struct bpf_d *)~0; /* mark device in use */ 407 mtx_unlock(&bpf_mtx); 408 409 if ((dev->si_flags & SI_NAMED) == 0) 410 make_dev(&bpf_cdevsw, minor(dev), UID_ROOT, GID_WHEEL, 0600, 411 "bpf%d", dev2unit(dev)); 412 MALLOC(d, struct bpf_d *, sizeof(*d), M_BPF, M_WAITOK | M_ZERO); 413 dev->si_drv1 = d; 414 d->bd_bufsize = bpf_bufsize; 415 d->bd_sig = SIGIO; 416 d->bd_direction = BPF_D_INOUT; 417 d->bd_pid = td->td_proc->p_pid; 418 #ifdef MAC 419 mac_init_bpfdesc(d); 420 mac_create_bpfdesc(td->td_ucred, d); 421 #endif 422 mtx_init(&d->bd_mtx, devtoname(dev), "bpf cdev lock", MTX_DEF); 423 callout_init(&d->bd_callout, CALLOUT_MPSAFE); 424 knlist_init(&d->bd_sel.si_note, &d->bd_mtx, NULL, NULL, NULL); 425 426 return (0); 427 } 428 429 /* 430 * Close the descriptor by detaching it from its interface, 431 * deallocating its buffers, and marking it free. 432 */ 433 /* ARGSUSED */ 434 static int 435 bpfclose(struct cdev *dev, int flags, int fmt, struct thread *td) 436 { 437 struct bpf_d *d = dev->si_drv1; 438 439 BPFD_LOCK(d); 440 if (d->bd_state == BPF_WAITING) 441 callout_stop(&d->bd_callout); 442 d->bd_state = BPF_IDLE; 443 BPFD_UNLOCK(d); 444 funsetown(&d->bd_sigio); 445 mtx_lock(&bpf_mtx); 446 if (d->bd_bif) 447 bpf_detachd(d); 448 mtx_unlock(&bpf_mtx); 449 selwakeuppri(&d->bd_sel, PRINET); 450 #ifdef MAC 451 mac_destroy_bpfdesc(d); 452 #endif /* MAC */ 453 knlist_destroy(&d->bd_sel.si_note); 454 bpf_freed(d); 455 dev->si_drv1 = NULL; 456 free(d, M_BPF); 457 458 return (0); 459 } 460 461 462 /* 463 * Rotate the packet buffers in descriptor d. Move the store buffer 464 * into the hold slot, and the free buffer into the store slot. 465 * Zero the length of the new store buffer. 466 */ 467 #define ROTATE_BUFFERS(d) \ 468 (d)->bd_hbuf = (d)->bd_sbuf; \ 469 (d)->bd_hlen = (d)->bd_slen; \ 470 (d)->bd_sbuf = (d)->bd_fbuf; \ 471 (d)->bd_slen = 0; \ 472 (d)->bd_fbuf = NULL; 473 /* 474 * bpfread - read next chunk of packets from buffers 475 */ 476 static int 477 bpfread(struct cdev *dev, struct uio *uio, int ioflag) 478 { 479 struct bpf_d *d = dev->si_drv1; 480 int timed_out; 481 int error; 482 483 /* 484 * Restrict application to use a buffer the same size as 485 * as kernel buffers. 486 */ 487 if (uio->uio_resid != d->bd_bufsize) 488 return (EINVAL); 489 490 BPFD_LOCK(d); 491 d->bd_pid = curthread->td_proc->p_pid; 492 if (d->bd_state == BPF_WAITING) 493 callout_stop(&d->bd_callout); 494 timed_out = (d->bd_state == BPF_TIMED_OUT); 495 d->bd_state = BPF_IDLE; 496 /* 497 * If the hold buffer is empty, then do a timed sleep, which 498 * ends when the timeout expires or when enough packets 499 * have arrived to fill the store buffer. 500 */ 501 while (d->bd_hbuf == NULL) { 502 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 503 /* 504 * A packet(s) either arrived since the previous 505 * read or arrived while we were asleep. 506 * Rotate the buffers and return what's here. 507 */ 508 ROTATE_BUFFERS(d); 509 break; 510 } 511 512 /* 513 * No data is available, check to see if the bpf device 514 * is still pointed at a real interface. If not, return 515 * ENXIO so that the userland process knows to rebind 516 * it before using it again. 517 */ 518 if (d->bd_bif == NULL) { 519 BPFD_UNLOCK(d); 520 return (ENXIO); 521 } 522 523 if (ioflag & O_NONBLOCK) { 524 BPFD_UNLOCK(d); 525 return (EWOULDBLOCK); 526 } 527 error = msleep(d, &d->bd_mtx, PRINET|PCATCH, 528 "bpf", d->bd_rtout); 529 if (error == EINTR || error == ERESTART) { 530 BPFD_UNLOCK(d); 531 return (error); 532 } 533 if (error == EWOULDBLOCK) { 534 /* 535 * On a timeout, return what's in the buffer, 536 * which may be nothing. If there is something 537 * in the store buffer, we can rotate the buffers. 538 */ 539 if (d->bd_hbuf) 540 /* 541 * We filled up the buffer in between 542 * getting the timeout and arriving 543 * here, so we don't need to rotate. 544 */ 545 break; 546 547 if (d->bd_slen == 0) { 548 BPFD_UNLOCK(d); 549 return (0); 550 } 551 ROTATE_BUFFERS(d); 552 break; 553 } 554 } 555 /* 556 * At this point, we know we have something in the hold slot. 557 */ 558 BPFD_UNLOCK(d); 559 560 /* 561 * Move data from hold buffer into user space. 562 * We know the entire buffer is transferred since 563 * we checked above that the read buffer is bpf_bufsize bytes. 564 */ 565 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 566 567 BPFD_LOCK(d); 568 d->bd_fbuf = d->bd_hbuf; 569 d->bd_hbuf = NULL; 570 d->bd_hlen = 0; 571 BPFD_UNLOCK(d); 572 573 return (error); 574 } 575 576 577 /* 578 * If there are processes sleeping on this descriptor, wake them up. 579 */ 580 static __inline void 581 bpf_wakeup(struct bpf_d *d) 582 { 583 584 BPFD_LOCK_ASSERT(d); 585 if (d->bd_state == BPF_WAITING) { 586 callout_stop(&d->bd_callout); 587 d->bd_state = BPF_IDLE; 588 } 589 wakeup(d); 590 if (d->bd_async && d->bd_sig && d->bd_sigio) 591 pgsigio(&d->bd_sigio, d->bd_sig, 0); 592 593 selwakeuppri(&d->bd_sel, PRINET); 594 KNOTE_LOCKED(&d->bd_sel.si_note, 0); 595 } 596 597 static void 598 bpf_timed_out(void *arg) 599 { 600 struct bpf_d *d = (struct bpf_d *)arg; 601 602 BPFD_LOCK(d); 603 if (d->bd_state == BPF_WAITING) { 604 d->bd_state = BPF_TIMED_OUT; 605 if (d->bd_slen != 0) 606 bpf_wakeup(d); 607 } 608 BPFD_UNLOCK(d); 609 } 610 611 static int 612 bpfwrite(struct cdev *dev, struct uio *uio, int ioflag) 613 { 614 struct bpf_d *d = dev->si_drv1; 615 struct ifnet *ifp; 616 struct mbuf *m, *mc; 617 struct sockaddr dst; 618 int error, hlen; 619 620 d->bd_pid = curthread->td_proc->p_pid; 621 if (d->bd_bif == NULL) 622 return (ENXIO); 623 624 ifp = d->bd_bif->bif_ifp; 625 626 if ((ifp->if_flags & IFF_UP) == 0) 627 return (ENETDOWN); 628 629 if (uio->uio_resid == 0) 630 return (0); 631 632 bzero(&dst, sizeof(dst)); 633 m = NULL; 634 hlen = 0; 635 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, ifp, 636 &m, &dst, &hlen, d->bd_wfilter); 637 if (error) 638 return (error); 639 640 if (d->bd_hdrcmplt) 641 dst.sa_family = pseudo_AF_HDRCMPLT; 642 643 if (d->bd_feedback) { 644 mc = m_dup(m, M_DONTWAIT); 645 if (mc != NULL) 646 mc->m_pkthdr.rcvif = ifp; 647 /* XXX Do not return the same packet twice. */ 648 if (d->bd_direction == BPF_D_INOUT) 649 m->m_flags |= M_SKIP_BPF; 650 } else 651 mc = NULL; 652 653 m->m_pkthdr.len -= hlen; 654 m->m_len -= hlen; 655 m->m_data += hlen; /* XXX */ 656 657 #ifdef MAC 658 BPFD_LOCK(d); 659 mac_create_mbuf_from_bpfdesc(d, m); 660 if (mc != NULL) 661 mac_create_mbuf_from_bpfdesc(d, mc); 662 BPFD_UNLOCK(d); 663 #endif 664 665 error = (*ifp->if_output)(ifp, m, &dst, NULL); 666 667 if (mc != NULL) { 668 if (error == 0) 669 (*ifp->if_input)(ifp, mc); 670 else 671 m_freem(mc); 672 } 673 674 return (error); 675 } 676 677 /* 678 * Reset a descriptor by flushing its packet buffer and clearing the 679 * receive and drop counts. 680 */ 681 static void 682 reset_d(struct bpf_d *d) 683 { 684 685 mtx_assert(&d->bd_mtx, MA_OWNED); 686 if (d->bd_hbuf) { 687 /* Free the hold buffer. */ 688 d->bd_fbuf = d->bd_hbuf; 689 d->bd_hbuf = NULL; 690 } 691 d->bd_slen = 0; 692 d->bd_hlen = 0; 693 d->bd_rcount = 0; 694 d->bd_dcount = 0; 695 d->bd_fcount = 0; 696 } 697 698 /* 699 * FIONREAD Check for read packet available. 700 * SIOCGIFADDR Get interface address - convenient hook to driver. 701 * BIOCGBLEN Get buffer len [for read()]. 702 * BIOCSETF Set ethernet read filter. 703 * BIOCSETWF Set ethernet write filter. 704 * BIOCFLUSH Flush read packet buffer. 705 * BIOCPROMISC Put interface into promiscuous mode. 706 * BIOCGDLT Get link layer type. 707 * BIOCGETIF Get interface name. 708 * BIOCSETIF Set interface. 709 * BIOCSRTIMEOUT Set read timeout. 710 * BIOCGRTIMEOUT Get read timeout. 711 * BIOCGSTATS Get packet stats. 712 * BIOCIMMEDIATE Set immediate mode. 713 * BIOCVERSION Get filter language version. 714 * BIOCGHDRCMPLT Get "header already complete" flag 715 * BIOCSHDRCMPLT Set "header already complete" flag 716 * BIOCGDIRECTION Get packet direction flag 717 * BIOCSDIRECTION Set packet direction flag 718 * BIOCLOCK Set "locked" flag 719 * BIOCFEEDBACK Set packet feedback mode. 720 */ 721 /* ARGSUSED */ 722 static int 723 bpfioctl(struct cdev *dev, u_long cmd, caddr_t addr, int flags, 724 struct thread *td) 725 { 726 struct bpf_d *d = dev->si_drv1; 727 int error = 0; 728 729 /* 730 * Refresh PID associated with this descriptor. 731 */ 732 BPFD_LOCK(d); 733 d->bd_pid = td->td_proc->p_pid; 734 if (d->bd_state == BPF_WAITING) 735 callout_stop(&d->bd_callout); 736 d->bd_state = BPF_IDLE; 737 BPFD_UNLOCK(d); 738 739 if (d->bd_locked == 1) { 740 switch (cmd) { 741 case BIOCGBLEN: 742 case BIOCFLUSH: 743 case BIOCGDLT: 744 case BIOCGDLTLIST: 745 case BIOCGETIF: 746 case BIOCGRTIMEOUT: 747 case BIOCGSTATS: 748 case BIOCVERSION: 749 case BIOCGRSIG: 750 case BIOCGHDRCMPLT: 751 case BIOCFEEDBACK: 752 case FIONREAD: 753 case BIOCLOCK: 754 case BIOCSRTIMEOUT: 755 case BIOCIMMEDIATE: 756 case TIOCGPGRP: 757 break; 758 default: 759 return (EPERM); 760 } 761 } 762 switch (cmd) { 763 764 default: 765 error = EINVAL; 766 break; 767 768 /* 769 * Check for read packet available. 770 */ 771 case FIONREAD: 772 { 773 int n; 774 775 BPFD_LOCK(d); 776 n = d->bd_slen; 777 if (d->bd_hbuf) 778 n += d->bd_hlen; 779 BPFD_UNLOCK(d); 780 781 *(int *)addr = n; 782 break; 783 } 784 785 case SIOCGIFADDR: 786 { 787 struct ifnet *ifp; 788 789 if (d->bd_bif == NULL) 790 error = EINVAL; 791 else { 792 ifp = d->bd_bif->bif_ifp; 793 error = (*ifp->if_ioctl)(ifp, cmd, addr); 794 } 795 break; 796 } 797 798 /* 799 * Get buffer len [for read()]. 800 */ 801 case BIOCGBLEN: 802 *(u_int *)addr = d->bd_bufsize; 803 break; 804 805 /* 806 * Set buffer length. 807 */ 808 case BIOCSBLEN: 809 if (d->bd_bif != NULL) 810 error = EINVAL; 811 else { 812 u_int size = *(u_int *)addr; 813 814 if (size > bpf_maxbufsize) 815 *(u_int *)addr = size = bpf_maxbufsize; 816 else if (size < BPF_MINBUFSIZE) 817 *(u_int *)addr = size = BPF_MINBUFSIZE; 818 d->bd_bufsize = size; 819 } 820 break; 821 822 /* 823 * Set link layer read filter. 824 */ 825 case BIOCSETF: 826 case BIOCSETWF: 827 error = bpf_setf(d, (struct bpf_program *)addr, cmd); 828 break; 829 830 /* 831 * Flush read packet buffer. 832 */ 833 case BIOCFLUSH: 834 BPFD_LOCK(d); 835 reset_d(d); 836 BPFD_UNLOCK(d); 837 break; 838 839 /* 840 * Put interface into promiscuous mode. 841 */ 842 case BIOCPROMISC: 843 if (d->bd_bif == NULL) { 844 /* 845 * No interface attached yet. 846 */ 847 error = EINVAL; 848 break; 849 } 850 if (d->bd_promisc == 0) { 851 error = ifpromisc(d->bd_bif->bif_ifp, 1); 852 if (error == 0) 853 d->bd_promisc = 1; 854 } 855 break; 856 857 /* 858 * Get current data link type. 859 */ 860 case BIOCGDLT: 861 if (d->bd_bif == NULL) 862 error = EINVAL; 863 else 864 *(u_int *)addr = d->bd_bif->bif_dlt; 865 break; 866 867 /* 868 * Get a list of supported data link types. 869 */ 870 case BIOCGDLTLIST: 871 if (d->bd_bif == NULL) 872 error = EINVAL; 873 else 874 error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); 875 break; 876 877 /* 878 * Set data link type. 879 */ 880 case BIOCSDLT: 881 if (d->bd_bif == NULL) 882 error = EINVAL; 883 else 884 error = bpf_setdlt(d, *(u_int *)addr); 885 break; 886 887 /* 888 * Get interface name. 889 */ 890 case BIOCGETIF: 891 if (d->bd_bif == NULL) 892 error = EINVAL; 893 else { 894 struct ifnet *const ifp = d->bd_bif->bif_ifp; 895 struct ifreq *const ifr = (struct ifreq *)addr; 896 897 strlcpy(ifr->ifr_name, ifp->if_xname, 898 sizeof(ifr->ifr_name)); 899 } 900 break; 901 902 /* 903 * Set interface. 904 */ 905 case BIOCSETIF: 906 error = bpf_setif(d, (struct ifreq *)addr); 907 break; 908 909 /* 910 * Set read timeout. 911 */ 912 case BIOCSRTIMEOUT: 913 { 914 struct timeval *tv = (struct timeval *)addr; 915 916 /* 917 * Subtract 1 tick from tvtohz() since this isn't 918 * a one-shot timer. 919 */ 920 if ((error = itimerfix(tv)) == 0) 921 d->bd_rtout = tvtohz(tv) - 1; 922 break; 923 } 924 925 /* 926 * Get read timeout. 927 */ 928 case BIOCGRTIMEOUT: 929 { 930 struct timeval *tv = (struct timeval *)addr; 931 932 tv->tv_sec = d->bd_rtout / hz; 933 tv->tv_usec = (d->bd_rtout % hz) * tick; 934 break; 935 } 936 937 /* 938 * Get packet stats. 939 */ 940 case BIOCGSTATS: 941 { 942 struct bpf_stat *bs = (struct bpf_stat *)addr; 943 944 bs->bs_recv = d->bd_rcount; 945 bs->bs_drop = d->bd_dcount; 946 break; 947 } 948 949 /* 950 * Set immediate mode. 951 */ 952 case BIOCIMMEDIATE: 953 d->bd_immediate = *(u_int *)addr; 954 break; 955 956 case BIOCVERSION: 957 { 958 struct bpf_version *bv = (struct bpf_version *)addr; 959 960 bv->bv_major = BPF_MAJOR_VERSION; 961 bv->bv_minor = BPF_MINOR_VERSION; 962 break; 963 } 964 965 /* 966 * Get "header already complete" flag 967 */ 968 case BIOCGHDRCMPLT: 969 *(u_int *)addr = d->bd_hdrcmplt; 970 break; 971 972 /* 973 * Set "header already complete" flag 974 */ 975 case BIOCSHDRCMPLT: 976 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 977 break; 978 979 /* 980 * Get packet direction flag 981 */ 982 case BIOCGDIRECTION: 983 *(u_int *)addr = d->bd_direction; 984 break; 985 986 /* 987 * Set packet direction flag 988 */ 989 case BIOCSDIRECTION: 990 { 991 u_int direction; 992 993 direction = *(u_int *)addr; 994 switch (direction) { 995 case BPF_D_IN: 996 case BPF_D_INOUT: 997 case BPF_D_OUT: 998 d->bd_direction = direction; 999 break; 1000 default: 1001 error = EINVAL; 1002 } 1003 } 1004 break; 1005 1006 case BIOCFEEDBACK: 1007 d->bd_feedback = *(u_int *)addr; 1008 break; 1009 1010 case BIOCLOCK: 1011 d->bd_locked = 1; 1012 break; 1013 1014 case FIONBIO: /* Non-blocking I/O */ 1015 break; 1016 1017 case FIOASYNC: /* Send signal on receive packets */ 1018 d->bd_async = *(int *)addr; 1019 break; 1020 1021 case FIOSETOWN: 1022 error = fsetown(*(int *)addr, &d->bd_sigio); 1023 break; 1024 1025 case FIOGETOWN: 1026 *(int *)addr = fgetown(&d->bd_sigio); 1027 break; 1028 1029 /* This is deprecated, FIOSETOWN should be used instead. */ 1030 case TIOCSPGRP: 1031 error = fsetown(-(*(int *)addr), &d->bd_sigio); 1032 break; 1033 1034 /* This is deprecated, FIOGETOWN should be used instead. */ 1035 case TIOCGPGRP: 1036 *(int *)addr = -fgetown(&d->bd_sigio); 1037 break; 1038 1039 case BIOCSRSIG: /* Set receive signal */ 1040 { 1041 u_int sig; 1042 1043 sig = *(u_int *)addr; 1044 1045 if (sig >= NSIG) 1046 error = EINVAL; 1047 else 1048 d->bd_sig = sig; 1049 break; 1050 } 1051 case BIOCGRSIG: 1052 *(u_int *)addr = d->bd_sig; 1053 break; 1054 } 1055 return (error); 1056 } 1057 1058 /* 1059 * Set d's packet filter program to fp. If this file already has a filter, 1060 * free it and replace it. Returns EINVAL for bogus requests. 1061 */ 1062 static int 1063 bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd) 1064 { 1065 struct bpf_insn *fcode, *old; 1066 u_int wfilter, flen, size; 1067 #ifdef BPF_JITTER 1068 bpf_jit_filter *ofunc; 1069 #endif 1070 1071 if (cmd == BIOCSETWF) { 1072 old = d->bd_wfilter; 1073 wfilter = 1; 1074 #ifdef BPF_JITTER 1075 ofunc = NULL; 1076 #endif 1077 } else { 1078 wfilter = 0; 1079 old = d->bd_rfilter; 1080 #ifdef BPF_JITTER 1081 ofunc = d->bd_bfilter; 1082 #endif 1083 } 1084 if (fp->bf_insns == NULL) { 1085 if (fp->bf_len != 0) 1086 return (EINVAL); 1087 BPFD_LOCK(d); 1088 if (wfilter) 1089 d->bd_wfilter = NULL; 1090 else { 1091 d->bd_rfilter = NULL; 1092 #ifdef BPF_JITTER 1093 d->bd_bfilter = NULL; 1094 #endif 1095 } 1096 reset_d(d); 1097 BPFD_UNLOCK(d); 1098 if (old != NULL) 1099 free((caddr_t)old, M_BPF); 1100 #ifdef BPF_JITTER 1101 if (ofunc != NULL) 1102 bpf_destroy_jit_filter(ofunc); 1103 #endif 1104 return (0); 1105 } 1106 flen = fp->bf_len; 1107 if (flen > bpf_maxinsns) 1108 return (EINVAL); 1109 1110 size = flen * sizeof(*fp->bf_insns); 1111 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK); 1112 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 1113 bpf_validate(fcode, (int)flen)) { 1114 BPFD_LOCK(d); 1115 if (wfilter) 1116 d->bd_wfilter = fcode; 1117 else { 1118 d->bd_rfilter = fcode; 1119 #ifdef BPF_JITTER 1120 d->bd_bfilter = bpf_jitter(fcode, flen); 1121 #endif 1122 } 1123 reset_d(d); 1124 BPFD_UNLOCK(d); 1125 if (old != NULL) 1126 free((caddr_t)old, M_BPF); 1127 #ifdef BPF_JITTER 1128 if (ofunc != NULL) 1129 bpf_destroy_jit_filter(ofunc); 1130 #endif 1131 1132 return (0); 1133 } 1134 free((caddr_t)fcode, M_BPF); 1135 return (EINVAL); 1136 } 1137 1138 /* 1139 * Detach a file from its current interface (if attached at all) and attach 1140 * to the interface indicated by the name stored in ifr. 1141 * Return an errno or 0. 1142 */ 1143 static int 1144 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 1145 { 1146 struct bpf_if *bp; 1147 struct ifnet *theywant; 1148 1149 theywant = ifunit(ifr->ifr_name); 1150 if (theywant == NULL || theywant->if_bpf == NULL) 1151 return (ENXIO); 1152 1153 bp = theywant->if_bpf; 1154 /* 1155 * Allocate the packet buffers if we need to. 1156 * If we're already attached to requested interface, 1157 * just flush the buffer. 1158 */ 1159 if (d->bd_sbuf == NULL) 1160 bpf_allocbufs(d); 1161 if (bp != d->bd_bif) { 1162 if (d->bd_bif) 1163 /* 1164 * Detach if attached to something else. 1165 */ 1166 bpf_detachd(d); 1167 1168 bpf_attachd(d, bp); 1169 } 1170 BPFD_LOCK(d); 1171 reset_d(d); 1172 BPFD_UNLOCK(d); 1173 return (0); 1174 } 1175 1176 /* 1177 * Support for select() and poll() system calls 1178 * 1179 * Return true iff the specific operation will not block indefinitely. 1180 * Otherwise, return false but make a note that a selwakeup() must be done. 1181 */ 1182 static int 1183 bpfpoll(struct cdev *dev, int events, struct thread *td) 1184 { 1185 struct bpf_d *d; 1186 int revents; 1187 1188 d = dev->si_drv1; 1189 if (d->bd_bif == NULL) 1190 return (ENXIO); 1191 1192 /* 1193 * Refresh PID associated with this descriptor. 1194 */ 1195 revents = events & (POLLOUT | POLLWRNORM); 1196 BPFD_LOCK(d); 1197 d->bd_pid = td->td_proc->p_pid; 1198 if (events & (POLLIN | POLLRDNORM)) { 1199 if (bpf_ready(d)) 1200 revents |= events & (POLLIN | POLLRDNORM); 1201 else { 1202 selrecord(td, &d->bd_sel); 1203 /* Start the read timeout if necessary. */ 1204 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1205 callout_reset(&d->bd_callout, d->bd_rtout, 1206 bpf_timed_out, d); 1207 d->bd_state = BPF_WAITING; 1208 } 1209 } 1210 } 1211 BPFD_UNLOCK(d); 1212 return (revents); 1213 } 1214 1215 /* 1216 * Support for kevent() system call. Register EVFILT_READ filters and 1217 * reject all others. 1218 */ 1219 int 1220 bpfkqfilter(struct cdev *dev, struct knote *kn) 1221 { 1222 struct bpf_d *d = (struct bpf_d *)dev->si_drv1; 1223 1224 if (kn->kn_filter != EVFILT_READ) 1225 return (1); 1226 1227 /* 1228 * Refresh PID associated with this descriptor. 1229 */ 1230 BPFD_LOCK(d); 1231 d->bd_pid = curthread->td_proc->p_pid; 1232 kn->kn_fop = &bpfread_filtops; 1233 kn->kn_hook = d; 1234 knlist_add(&d->bd_sel.si_note, kn, 1); 1235 BPFD_UNLOCK(d); 1236 1237 return (0); 1238 } 1239 1240 static void 1241 filt_bpfdetach(struct knote *kn) 1242 { 1243 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1244 1245 knlist_remove(&d->bd_sel.si_note, kn, 0); 1246 } 1247 1248 static int 1249 filt_bpfread(struct knote *kn, long hint) 1250 { 1251 struct bpf_d *d = (struct bpf_d *)kn->kn_hook; 1252 int ready; 1253 1254 BPFD_LOCK_ASSERT(d); 1255 ready = bpf_ready(d); 1256 if (ready) { 1257 kn->kn_data = d->bd_slen; 1258 if (d->bd_hbuf) 1259 kn->kn_data += d->bd_hlen; 1260 } 1261 else if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1262 callout_reset(&d->bd_callout, d->bd_rtout, 1263 bpf_timed_out, d); 1264 d->bd_state = BPF_WAITING; 1265 } 1266 1267 return (ready); 1268 } 1269 1270 /* 1271 * Incoming linkage from device drivers. Process the packet pkt, of length 1272 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1273 * by each process' filter, and if accepted, stashed into the corresponding 1274 * buffer. 1275 */ 1276 void 1277 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1278 { 1279 struct bpf_d *d; 1280 u_int slen; 1281 int gottime; 1282 struct timeval tv; 1283 1284 gottime = 0; 1285 BPFIF_LOCK(bp); 1286 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1287 BPFD_LOCK(d); 1288 ++d->bd_rcount; 1289 #ifdef BPF_JITTER 1290 if (bpf_jitter_enable != 0 && d->bd_bfilter != NULL) 1291 slen = (*(d->bd_bfilter->func))(pkt, pktlen, pktlen); 1292 else 1293 #endif 1294 slen = bpf_filter(d->bd_rfilter, pkt, pktlen, pktlen); 1295 if (slen != 0) { 1296 d->bd_fcount++; 1297 if (!gottime) { 1298 microtime(&tv); 1299 gottime = 1; 1300 } 1301 #ifdef MAC 1302 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1303 #endif 1304 catchpacket(d, pkt, pktlen, slen, bcopy, &tv); 1305 } 1306 BPFD_UNLOCK(d); 1307 } 1308 BPFIF_UNLOCK(bp); 1309 } 1310 1311 /* 1312 * Copy data from an mbuf chain into a buffer. This code is derived 1313 * from m_copydata in sys/uipc_mbuf.c. 1314 */ 1315 static void 1316 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len) 1317 { 1318 const struct mbuf *m; 1319 u_int count; 1320 u_char *dst; 1321 1322 m = src_arg; 1323 dst = dst_arg; 1324 while (len > 0) { 1325 if (m == NULL) 1326 panic("bpf_mcopy"); 1327 count = min(m->m_len, len); 1328 bcopy(mtod(m, void *), dst, count); 1329 m = m->m_next; 1330 dst += count; 1331 len -= count; 1332 } 1333 } 1334 1335 #define BPF_CHECK_DIRECTION(d, m) \ 1336 if (((d)->bd_direction == BPF_D_IN && (m)->m_pkthdr.rcvif == NULL) || \ 1337 ((d)->bd_direction == BPF_D_OUT && (m)->m_pkthdr.rcvif != NULL)) 1338 1339 /* 1340 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1341 */ 1342 void 1343 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1344 { 1345 struct bpf_d *d; 1346 u_int pktlen, slen; 1347 int gottime; 1348 struct timeval tv; 1349 1350 if (m->m_flags & M_SKIP_BPF) { 1351 m->m_flags &= ~M_SKIP_BPF; 1352 return; 1353 } 1354 1355 gottime = 0; 1356 1357 pktlen = m_length(m, NULL); 1358 1359 BPFIF_LOCK(bp); 1360 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1361 BPF_CHECK_DIRECTION(d, m) 1362 continue; 1363 BPFD_LOCK(d); 1364 ++d->bd_rcount; 1365 #ifdef BPF_JITTER 1366 /* XXX We cannot handle multiple mbufs. */ 1367 if (bpf_jitter_enable != 0 && d->bd_bfilter != NULL && 1368 m->m_next == NULL) 1369 slen = (*(d->bd_bfilter->func))(mtod(m, u_char *), 1370 pktlen, pktlen); 1371 else 1372 #endif 1373 slen = bpf_filter(d->bd_rfilter, (u_char *)m, pktlen, 0); 1374 if (slen != 0) { 1375 d->bd_fcount++; 1376 if (!gottime) { 1377 microtime(&tv); 1378 gottime = 1; 1379 } 1380 #ifdef MAC 1381 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1382 #endif 1383 catchpacket(d, (u_char *)m, pktlen, slen, 1384 bpf_mcopy, &tv); 1385 } 1386 BPFD_UNLOCK(d); 1387 } 1388 BPFIF_UNLOCK(bp); 1389 } 1390 1391 /* 1392 * Incoming linkage from device drivers, when packet is in 1393 * an mbuf chain and to be prepended by a contiguous header. 1394 */ 1395 void 1396 bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) 1397 { 1398 struct mbuf mb; 1399 struct bpf_d *d; 1400 u_int pktlen, slen; 1401 int gottime; 1402 struct timeval tv; 1403 1404 if (m->m_flags & M_SKIP_BPF) { 1405 m->m_flags &= ~M_SKIP_BPF; 1406 return; 1407 } 1408 1409 gottime = 0; 1410 1411 pktlen = m_length(m, NULL); 1412 /* 1413 * Craft on-stack mbuf suitable for passing to bpf_filter. 1414 * Note that we cut corners here; we only setup what's 1415 * absolutely needed--this mbuf should never go anywhere else. 1416 */ 1417 mb.m_next = m; 1418 mb.m_data = data; 1419 mb.m_len = dlen; 1420 pktlen += dlen; 1421 1422 BPFIF_LOCK(bp); 1423 LIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1424 BPF_CHECK_DIRECTION(d, m) 1425 continue; 1426 BPFD_LOCK(d); 1427 ++d->bd_rcount; 1428 slen = bpf_filter(d->bd_rfilter, (u_char *)&mb, pktlen, 0); 1429 if (slen != 0) { 1430 d->bd_fcount++; 1431 if (!gottime) { 1432 microtime(&tv); 1433 gottime = 1; 1434 } 1435 #ifdef MAC 1436 if (mac_check_bpfdesc_receive(d, bp->bif_ifp) == 0) 1437 #endif 1438 catchpacket(d, (u_char *)&mb, pktlen, slen, 1439 bpf_mcopy, &tv); 1440 } 1441 BPFD_UNLOCK(d); 1442 } 1443 BPFIF_UNLOCK(bp); 1444 } 1445 1446 #undef BPF_CHECK_DIRECTION 1447 1448 /* 1449 * Move the packet data from interface memory (pkt) into the 1450 * store buffer. "cpfn" is the routine called to do the actual data 1451 * transfer. bcopy is passed in to copy contiguous chunks, while 1452 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1453 * pkt is really an mbuf. 1454 */ 1455 static void 1456 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1457 void (*cpfn)(const void *, void *, size_t), struct timeval *tv) 1458 { 1459 struct bpf_hdr *hp; 1460 int totlen, curlen; 1461 int hdrlen = d->bd_bif->bif_hdrlen; 1462 int do_wakeup = 0; 1463 1464 BPFD_LOCK_ASSERT(d); 1465 /* 1466 * Figure out how many bytes to move. If the packet is 1467 * greater or equal to the snapshot length, transfer that 1468 * much. Otherwise, transfer the whole packet (unless 1469 * we hit the buffer size limit). 1470 */ 1471 totlen = hdrlen + min(snaplen, pktlen); 1472 if (totlen > d->bd_bufsize) 1473 totlen = d->bd_bufsize; 1474 1475 /* 1476 * Round up the end of the previous packet to the next longword. 1477 */ 1478 curlen = BPF_WORDALIGN(d->bd_slen); 1479 if (curlen + totlen > d->bd_bufsize) { 1480 /* 1481 * This packet will overflow the storage buffer. 1482 * Rotate the buffers if we can, then wakeup any 1483 * pending reads. 1484 */ 1485 if (d->bd_fbuf == NULL) { 1486 /* 1487 * We haven't completed the previous read yet, 1488 * so drop the packet. 1489 */ 1490 ++d->bd_dcount; 1491 return; 1492 } 1493 ROTATE_BUFFERS(d); 1494 do_wakeup = 1; 1495 curlen = 0; 1496 } 1497 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) 1498 /* 1499 * Immediate mode is set, or the read timeout has 1500 * already expired during a select call. A packet 1501 * arrived, so the reader should be woken up. 1502 */ 1503 do_wakeup = 1; 1504 1505 /* 1506 * Append the bpf header. 1507 */ 1508 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1509 hp->bh_tstamp = *tv; 1510 hp->bh_datalen = pktlen; 1511 hp->bh_hdrlen = hdrlen; 1512 /* 1513 * Copy the packet data into the store buffer and update its length. 1514 */ 1515 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1516 d->bd_slen = curlen + totlen; 1517 1518 if (do_wakeup) 1519 bpf_wakeup(d); 1520 } 1521 1522 /* 1523 * Initialize all nonzero fields of a descriptor. 1524 */ 1525 static void 1526 bpf_allocbufs(struct bpf_d *d) 1527 { 1528 1529 KASSERT(d->bd_fbuf == NULL, ("bpf_allocbufs: bd_fbuf != NULL")); 1530 KASSERT(d->bd_sbuf == NULL, ("bpf_allocbufs: bd_sbuf != NULL")); 1531 KASSERT(d->bd_hbuf == NULL, ("bpf_allocbufs: bd_hbuf != NULL")); 1532 1533 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1534 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1535 d->bd_slen = 0; 1536 d->bd_hlen = 0; 1537 } 1538 1539 /* 1540 * Free buffers currently in use by a descriptor. 1541 * Called on close. 1542 */ 1543 static void 1544 bpf_freed(struct bpf_d *d) 1545 { 1546 /* 1547 * We don't need to lock out interrupts since this descriptor has 1548 * been detached from its interface and it yet hasn't been marked 1549 * free. 1550 */ 1551 if (d->bd_sbuf != NULL) { 1552 free(d->bd_sbuf, M_BPF); 1553 if (d->bd_hbuf != NULL) 1554 free(d->bd_hbuf, M_BPF); 1555 if (d->bd_fbuf != NULL) 1556 free(d->bd_fbuf, M_BPF); 1557 } 1558 if (d->bd_rfilter) { 1559 free((caddr_t)d->bd_rfilter, M_BPF); 1560 #ifdef BPF_JITTER 1561 bpf_destroy_jit_filter(d->bd_bfilter); 1562 #endif 1563 } 1564 if (d->bd_wfilter) 1565 free((caddr_t)d->bd_wfilter, M_BPF); 1566 mtx_destroy(&d->bd_mtx); 1567 } 1568 1569 /* 1570 * Attach an interface to bpf. dlt is the link layer type; hdrlen is the 1571 * fixed size of the link header (variable length headers not yet supported). 1572 */ 1573 void 1574 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1575 { 1576 1577 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); 1578 } 1579 1580 /* 1581 * Attach an interface to bpf. ifp is a pointer to the structure 1582 * defining the interface to be attached, dlt is the link layer type, 1583 * and hdrlen is the fixed size of the link header (variable length 1584 * headers are not yet supporrted). 1585 */ 1586 void 1587 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1588 { 1589 struct bpf_if *bp; 1590 1591 bp = malloc(sizeof(*bp), M_BPF, M_NOWAIT | M_ZERO); 1592 if (bp == NULL) 1593 panic("bpfattach"); 1594 1595 LIST_INIT(&bp->bif_dlist); 1596 bp->bif_ifp = ifp; 1597 bp->bif_dlt = dlt; 1598 mtx_init(&bp->bif_mtx, "bpf interface lock", NULL, MTX_DEF); 1599 KASSERT(*driverp == NULL, ("bpfattach2: driverp already initialized")); 1600 *driverp = bp; 1601 1602 mtx_lock(&bpf_mtx); 1603 LIST_INSERT_HEAD(&bpf_iflist, bp, bif_next); 1604 mtx_unlock(&bpf_mtx); 1605 1606 /* 1607 * Compute the length of the bpf header. This is not necessarily 1608 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1609 * that the network layer header begins on a longword boundary (for 1610 * performance reasons and to alleviate alignment restrictions). 1611 */ 1612 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1613 1614 if (bootverbose) 1615 if_printf(ifp, "bpf attached\n"); 1616 } 1617 1618 /* 1619 * Detach bpf from an interface. This involves detaching each descriptor 1620 * associated with the interface, and leaving bd_bif NULL. Notify each 1621 * descriptor as it's detached so that any sleepers wake up and get 1622 * ENXIO. 1623 */ 1624 void 1625 bpfdetach(struct ifnet *ifp) 1626 { 1627 struct bpf_if *bp; 1628 struct bpf_d *d; 1629 1630 /* Locate BPF interface information */ 1631 mtx_lock(&bpf_mtx); 1632 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1633 if (ifp == bp->bif_ifp) 1634 break; 1635 } 1636 1637 /* Interface wasn't attached */ 1638 if ((bp == NULL) || (bp->bif_ifp == NULL)) { 1639 mtx_unlock(&bpf_mtx); 1640 printf("bpfdetach: %s was not attached\n", ifp->if_xname); 1641 return; 1642 } 1643 1644 LIST_REMOVE(bp, bif_next); 1645 mtx_unlock(&bpf_mtx); 1646 1647 while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) { 1648 bpf_detachd(d); 1649 BPFD_LOCK(d); 1650 bpf_wakeup(d); 1651 BPFD_UNLOCK(d); 1652 } 1653 1654 mtx_destroy(&bp->bif_mtx); 1655 free(bp, M_BPF); 1656 } 1657 1658 /* 1659 * Get a list of available data link type of the interface. 1660 */ 1661 static int 1662 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 1663 { 1664 int n, error; 1665 struct ifnet *ifp; 1666 struct bpf_if *bp; 1667 1668 ifp = d->bd_bif->bif_ifp; 1669 n = 0; 1670 error = 0; 1671 mtx_lock(&bpf_mtx); 1672 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1673 if (bp->bif_ifp != ifp) 1674 continue; 1675 if (bfl->bfl_list != NULL) { 1676 if (n >= bfl->bfl_len) { 1677 mtx_unlock(&bpf_mtx); 1678 return (ENOMEM); 1679 } 1680 error = copyout(&bp->bif_dlt, 1681 bfl->bfl_list + n, sizeof(u_int)); 1682 } 1683 n++; 1684 } 1685 mtx_unlock(&bpf_mtx); 1686 bfl->bfl_len = n; 1687 return (error); 1688 } 1689 1690 /* 1691 * Set the data link type of a BPF instance. 1692 */ 1693 static int 1694 bpf_setdlt(struct bpf_d *d, u_int dlt) 1695 { 1696 int error, opromisc; 1697 struct ifnet *ifp; 1698 struct bpf_if *bp; 1699 1700 if (d->bd_bif->bif_dlt == dlt) 1701 return (0); 1702 ifp = d->bd_bif->bif_ifp; 1703 mtx_lock(&bpf_mtx); 1704 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1705 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1706 break; 1707 } 1708 mtx_unlock(&bpf_mtx); 1709 if (bp != NULL) { 1710 opromisc = d->bd_promisc; 1711 bpf_detachd(d); 1712 bpf_attachd(d, bp); 1713 BPFD_LOCK(d); 1714 reset_d(d); 1715 BPFD_UNLOCK(d); 1716 if (opromisc) { 1717 error = ifpromisc(bp->bif_ifp, 1); 1718 if (error) 1719 if_printf(bp->bif_ifp, 1720 "bpf_setdlt: ifpromisc failed (%d)\n", 1721 error); 1722 else 1723 d->bd_promisc = 1; 1724 } 1725 } 1726 return (bp == NULL ? EINVAL : 0); 1727 } 1728 1729 static void 1730 bpf_clone(void *arg, struct ucred *cred, char *name, int namelen, 1731 struct cdev **dev) 1732 { 1733 int u; 1734 1735 if (*dev != NULL) 1736 return; 1737 if (dev_stdclone(name, NULL, "bpf", &u) != 1) 1738 return; 1739 *dev = make_dev(&bpf_cdevsw, unit2minor(u), UID_ROOT, GID_WHEEL, 0600, 1740 "bpf%d", u); 1741 dev_ref(*dev); 1742 (*dev)->si_flags |= SI_CHEAPCLONE; 1743 return; 1744 } 1745 1746 static void 1747 bpf_drvinit(void *unused) 1748 { 1749 1750 mtx_init(&bpf_mtx, "bpf global lock", NULL, MTX_DEF); 1751 LIST_INIT(&bpf_iflist); 1752 EVENTHANDLER_REGISTER(dev_clone, bpf_clone, 0, 1000); 1753 } 1754 1755 static void 1756 bpfstats_fill_xbpf(struct xbpf_d *d, struct bpf_d *bd) 1757 { 1758 1759 bzero(d, sizeof(*d)); 1760 BPFD_LOCK_ASSERT(bd); 1761 d->bd_immediate = bd->bd_immediate; 1762 d->bd_promisc = bd->bd_promisc; 1763 d->bd_hdrcmplt = bd->bd_hdrcmplt; 1764 d->bd_direction = bd->bd_direction; 1765 d->bd_feedback = bd->bd_feedback; 1766 d->bd_async = bd->bd_async; 1767 d->bd_rcount = bd->bd_rcount; 1768 d->bd_dcount = bd->bd_dcount; 1769 d->bd_fcount = bd->bd_fcount; 1770 d->bd_sig = bd->bd_sig; 1771 d->bd_slen = bd->bd_slen; 1772 d->bd_hlen = bd->bd_hlen; 1773 d->bd_bufsize = bd->bd_bufsize; 1774 d->bd_pid = bd->bd_pid; 1775 strlcpy(d->bd_ifname, 1776 bd->bd_bif->bif_ifp->if_xname, IFNAMSIZ); 1777 d->bd_locked = bd->bd_locked; 1778 } 1779 1780 static int 1781 bpf_stats_sysctl(SYSCTL_HANDLER_ARGS) 1782 { 1783 struct xbpf_d *xbdbuf, *xbd; 1784 int index, error; 1785 struct bpf_if *bp; 1786 struct bpf_d *bd; 1787 1788 /* 1789 * XXX This is not technically correct. It is possible for non 1790 * privileged users to open bpf devices. It would make sense 1791 * if the users who opened the devices were able to retrieve 1792 * the statistics for them, too. 1793 */ 1794 error = priv_check(req->td, PRIV_NET_BPF); 1795 if (error) 1796 return (error); 1797 if (req->oldptr == NULL) 1798 return (SYSCTL_OUT(req, 0, bpf_bpfd_cnt * sizeof(*xbd))); 1799 if (bpf_bpfd_cnt == 0) 1800 return (SYSCTL_OUT(req, 0, 0)); 1801 xbdbuf = malloc(req->oldlen, M_BPF, M_WAITOK); 1802 mtx_lock(&bpf_mtx); 1803 if (req->oldlen < (bpf_bpfd_cnt * sizeof(*xbd))) { 1804 mtx_unlock(&bpf_mtx); 1805 free(xbdbuf, M_BPF); 1806 return (ENOMEM); 1807 } 1808 index = 0; 1809 LIST_FOREACH(bp, &bpf_iflist, bif_next) { 1810 BPFIF_LOCK(bp); 1811 LIST_FOREACH(bd, &bp->bif_dlist, bd_next) { 1812 xbd = &xbdbuf[index++]; 1813 BPFD_LOCK(bd); 1814 bpfstats_fill_xbpf(xbd, bd); 1815 BPFD_UNLOCK(bd); 1816 } 1817 BPFIF_UNLOCK(bp); 1818 } 1819 mtx_unlock(&bpf_mtx); 1820 error = SYSCTL_OUT(req, xbdbuf, index * sizeof(*xbd)); 1821 free(xbdbuf, M_BPF); 1822 return (error); 1823 } 1824 1825 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE,bpf_drvinit,NULL) 1826 1827 #else /* !DEV_BPF && !NETGRAPH_BPF */ 1828 /* 1829 * NOP stubs to allow bpf-using drivers to load and function. 1830 * 1831 * A 'better' implementation would allow the core bpf functionality 1832 * to be loaded at runtime. 1833 */ 1834 static struct bpf_if bp_null; 1835 1836 void 1837 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1838 { 1839 } 1840 1841 void 1842 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1843 { 1844 } 1845 1846 void 1847 bpf_mtap2(struct bpf_if *bp, void *d, u_int l, struct mbuf *m) 1848 { 1849 } 1850 1851 void 1852 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1853 { 1854 1855 bpfattach2(ifp, dlt, hdrlen, &ifp->if_bpf); 1856 } 1857 1858 void 1859 bpfattach2(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1860 { 1861 1862 *driverp = &bp_null; 1863 } 1864 1865 void 1866 bpfdetach(struct ifnet *ifp) 1867 { 1868 } 1869 1870 u_int 1871 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen) 1872 { 1873 return -1; /* "no filter" behaviour */ 1874 } 1875 1876 int 1877 bpf_validate(const struct bpf_insn *f, int len) 1878 { 1879 return 0; /* false */ 1880 } 1881 1882 #endif /* !DEV_BPF && !NETGRAPH_BPF */
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