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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)bpf.c 8.2 (Berkeley) 3/28/94 39 * 40 * $FreeBSD: src/sys/net/bpf.c,v 1.59.2.12 2002/04/14 21:41:48 luigi Exp $ 41 * $DragonFly: src/sys/net/bpf.c,v 1.27 2005/06/03 18:19:51 swildner Exp $ 42 */ 43 44 #include "use_bpf.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/conf.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/filedesc.h> 58 59 #include <sys/poll.h> 60 61 #include <sys/socket.h> 62 #include <sys/vnode.h> 63 64 #include <sys/thread2.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 MALLOC_DEFINE(M_BPF, "BPF", "BPF data"); 76 77 #if NBPF > 0 78 79 /* 80 * The default read buffer size is patchable. 81 */ 82 static int bpf_bufsize = BPF_DEFAULTBUFSIZE; 83 SYSCTL_INT(_debug, OID_AUTO, bpf_bufsize, CTLFLAG_RW, 84 &bpf_bufsize, 0, ""); 85 static int bpf_maxbufsize = BPF_MAXBUFSIZE; 86 SYSCTL_INT(_debug, OID_AUTO, bpf_maxbufsize, CTLFLAG_RW, 87 &bpf_maxbufsize, 0, ""); 88 89 /* 90 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 91 */ 92 static struct bpf_if *bpf_iflist; 93 94 static int bpf_allocbufs(struct bpf_d *); 95 static void bpf_attachd(struct bpf_d *d, struct bpf_if *bp); 96 static void bpf_detachd(struct bpf_d *d); 97 static void bpf_freed(struct bpf_d *); 98 static void bpf_mcopy(const void *, void *, size_t); 99 static int bpf_movein(struct uio *, int, struct mbuf **, 100 struct sockaddr *, int *); 101 static int bpf_setif(struct bpf_d *, struct ifreq *); 102 static void bpf_timed_out(void *); 103 static void bpf_wakeup(struct bpf_d *); 104 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int, 105 void (*)(const void *, void *, size_t)); 106 static void reset_d(struct bpf_d *); 107 static int bpf_setf(struct bpf_d *, struct bpf_program *); 108 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 109 static int bpf_setdlt(struct bpf_d *, u_int); 110 static void bpf_drvinit(void *unused); 111 112 static d_open_t bpfopen; 113 static d_close_t bpfclose; 114 static d_read_t bpfread; 115 static d_write_t bpfwrite; 116 static d_ioctl_t bpfioctl; 117 static d_poll_t bpfpoll; 118 119 #define CDEV_MAJOR 23 120 static struct cdevsw bpf_cdevsw = { 121 /* name */ "bpf", 122 /* maj */ CDEV_MAJOR, 123 /* flags */ 0, 124 /* port */ NULL, 125 /* clone */ NULL, 126 127 /* open */ bpfopen, 128 /* close */ bpfclose, 129 /* read */ bpfread, 130 /* write */ bpfwrite, 131 /* ioctl */ bpfioctl, 132 /* poll */ bpfpoll, 133 /* mmap */ nommap, 134 /* strategy */ nostrategy, 135 /* dump */ nodump, 136 /* psize */ nopsize 137 }; 138 139 140 static int 141 bpf_movein(struct uio *uio, int linktype, struct mbuf **mp, 142 struct sockaddr *sockp, int *datlen) 143 { 144 struct mbuf *m; 145 int error; 146 int len; 147 int hlen; 148 149 /* 150 * Build a sockaddr based on the data link layer type. 151 * We do this at this level because the ethernet header 152 * is copied directly into the data field of the sockaddr. 153 * In the case of SLIP, there is no header and the packet 154 * is forwarded as is. 155 * Also, we are careful to leave room at the front of the mbuf 156 * for the link level header. 157 */ 158 switch (linktype) { 159 160 case DLT_SLIP: 161 sockp->sa_family = AF_INET; 162 hlen = 0; 163 break; 164 165 case DLT_EN10MB: 166 sockp->sa_family = AF_UNSPEC; 167 /* XXX Would MAXLINKHDR be better? */ 168 hlen = sizeof(struct ether_header); 169 break; 170 171 case DLT_FDDI: 172 sockp->sa_family = AF_IMPLINK; 173 hlen = 0; 174 break; 175 176 case DLT_RAW: 177 case DLT_NULL: 178 sockp->sa_family = AF_UNSPEC; 179 hlen = 0; 180 break; 181 182 case DLT_ATM_RFC1483: 183 /* 184 * en atm driver requires 4-byte atm pseudo header. 185 * though it isn't standard, vpi:vci needs to be 186 * specified anyway. 187 */ 188 sockp->sa_family = AF_UNSPEC; 189 hlen = 12; /* XXX 4(ATM_PH) + 3(LLC) + 5(SNAP) */ 190 break; 191 192 case DLT_PPP: 193 sockp->sa_family = AF_UNSPEC; 194 hlen = 4; /* This should match PPP_HDRLEN */ 195 break; 196 197 default: 198 return(EIO); 199 } 200 201 len = uio->uio_resid; 202 *datlen = len - hlen; 203 if ((unsigned)len > MCLBYTES) 204 return(EIO); 205 206 MGETHDR(m, MB_WAIT, MT_DATA); 207 if (m == NULL) 208 return(ENOBUFS); 209 if (len > MHLEN) { 210 MCLGET(m, MB_WAIT); 211 if (!(m->m_flags & M_EXT)) { 212 error = ENOBUFS; 213 goto bad; 214 } 215 } 216 m->m_pkthdr.len = m->m_len = len; 217 m->m_pkthdr.rcvif = NULL; 218 *mp = m; 219 /* 220 * Make room for link header. 221 */ 222 if (hlen != 0) { 223 m->m_pkthdr.len -= hlen; 224 m->m_len -= hlen; 225 m->m_data += hlen; /* XXX */ 226 error = uiomove(sockp->sa_data, hlen, uio); 227 if (error) 228 goto bad; 229 } 230 error = uiomove(mtod(m, caddr_t), len - hlen, uio); 231 if (!error) 232 return(0); 233 bad: 234 m_freem(m); 235 return(error); 236 } 237 238 /* 239 * Attach file to the bpf interface, i.e. make d listen on bp. 240 * Must be called at splimp. 241 */ 242 static void 243 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 244 { 245 /* 246 * Point d at bp, and add d to the interface's list of listeners. 247 * Finally, point the driver's bpf cookie at the interface so 248 * it will divert packets to bpf. 249 */ 250 d->bd_bif = bp; 251 SLIST_INSERT_HEAD(&bp->bif_dlist, d, bd_next); 252 *bp->bif_driverp = bp; 253 } 254 255 /* 256 * Detach a file from its interface. 257 */ 258 static void 259 bpf_detachd(struct bpf_d *d) 260 { 261 int error; 262 struct bpf_if *bp; 263 struct ifnet *ifp; 264 265 bp = d->bd_bif; 266 ifp = bp->bif_ifp; 267 268 /* Remove d from the interface's descriptor list. */ 269 SLIST_REMOVE(&bp->bif_dlist, d, bpf_d, bd_next); 270 271 if (SLIST_EMPTY(&bp->bif_dlist)) { 272 /* 273 * Let the driver know that there are no more listeners. 274 */ 275 *bp->bif_driverp = NULL; 276 } 277 d->bd_bif = NULL; 278 /* 279 * Check if this descriptor had requested promiscuous mode. 280 * If so, turn it off. 281 */ 282 if (d->bd_promisc) { 283 d->bd_promisc = 0; 284 error = ifpromisc(ifp, 0); 285 if (error != 0 && error != ENXIO) { 286 /* 287 * ENXIO can happen if a pccard is unplugged, 288 * Something is really wrong if we were able to put 289 * the driver into promiscuous mode, but can't 290 * take it out. 291 */ 292 if_printf(ifp, "bpf_detach: ifpromisc failed(%d)\n", 293 error); 294 } 295 } 296 } 297 298 /* 299 * Open ethernet device. Returns ENXIO for illegal minor device number, 300 * EBUSY if file is open by another process. 301 */ 302 /* ARGSUSED */ 303 static int 304 bpfopen(dev_t dev, int flags, int fmt, struct thread *td) 305 { 306 struct bpf_d *d; 307 struct proc *p = td->td_proc; 308 309 KKASSERT(p != NULL); 310 311 if (p->p_ucred->cr_prison) 312 return(EPERM); 313 314 d = dev->si_drv1; 315 /* 316 * Each minor can be opened by only one process. If the requested 317 * minor is in use, return EBUSY. 318 */ 319 if (d != NULL) 320 return(EBUSY); 321 make_dev(&bpf_cdevsw, minor(dev), 0, 0, 0600, "bpf%d", lminor(dev)); 322 MALLOC(d, struct bpf_d *, sizeof *d, M_BPF, M_WAITOK | M_ZERO); 323 dev->si_drv1 = d; 324 d->bd_bufsize = bpf_bufsize; 325 d->bd_sig = SIGIO; 326 d->bd_seesent = 1; 327 callout_init(&d->bd_callout); 328 return(0); 329 } 330 331 /* 332 * Close the descriptor by detaching it from its interface, 333 * deallocating its buffers, and marking it free. 334 */ 335 /* ARGSUSED */ 336 static int 337 bpfclose(dev_t dev, int flags, int fmt, struct thread *td) 338 { 339 struct bpf_d *d = dev->si_drv1; 340 341 funsetown(d->bd_sigio); 342 crit_enter(); 343 if (d->bd_state == BPF_WAITING) 344 callout_stop(&d->bd_callout); 345 d->bd_state = BPF_IDLE; 346 if (d->bd_bif != NULL) 347 bpf_detachd(d); 348 crit_exit(); 349 bpf_freed(d); 350 dev->si_drv1 = NULL; 351 free(d, M_BPF); 352 353 return(0); 354 } 355 356 /* 357 * Rotate the packet buffers in descriptor d. Move the store buffer 358 * into the hold slot, and the free buffer into the store slot. 359 * Zero the length of the new store buffer. 360 */ 361 #define ROTATE_BUFFERS(d) \ 362 (d)->bd_hbuf = (d)->bd_sbuf; \ 363 (d)->bd_hlen = (d)->bd_slen; \ 364 (d)->bd_sbuf = (d)->bd_fbuf; \ 365 (d)->bd_slen = 0; \ 366 (d)->bd_fbuf = NULL; 367 /* 368 * bpfread - read next chunk of packets from buffers 369 */ 370 static int 371 bpfread(dev_t dev, struct uio *uio, int ioflag) 372 { 373 struct bpf_d *d = dev->si_drv1; 374 int timed_out; 375 int error; 376 377 /* 378 * Restrict application to use a buffer the same size as 379 * as kernel buffers. 380 */ 381 if (uio->uio_resid != d->bd_bufsize) 382 return(EINVAL); 383 384 crit_enter(); 385 if (d->bd_state == BPF_WAITING) 386 callout_stop(&d->bd_callout); 387 timed_out = (d->bd_state == BPF_TIMED_OUT); 388 d->bd_state = BPF_IDLE; 389 /* 390 * If the hold buffer is empty, then do a timed sleep, which 391 * ends when the timeout expires or when enough packets 392 * have arrived to fill the store buffer. 393 */ 394 while (d->bd_hbuf == NULL) { 395 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 396 /* 397 * A packet(s) either arrived since the previous 398 * read or arrived while we were asleep. 399 * Rotate the buffers and return what's here. 400 */ 401 ROTATE_BUFFERS(d); 402 break; 403 } 404 405 /* 406 * No data is available, check to see if the bpf device 407 * is still pointed at a real interface. If not, return 408 * ENXIO so that the userland process knows to rebind 409 * it before using it again. 410 */ 411 if (d->bd_bif == NULL) { 412 crit_exit(); 413 return(ENXIO); 414 } 415 416 if (ioflag & IO_NDELAY) { 417 crit_exit(); 418 return(EWOULDBLOCK); 419 } 420 error = tsleep(d, PCATCH, "bpf", d->bd_rtout); 421 if (error == EINTR || error == ERESTART) { 422 crit_exit(); 423 return(error); 424 } 425 if (error == EWOULDBLOCK) { 426 /* 427 * On a timeout, return what's in the buffer, 428 * which may be nothing. If there is something 429 * in the store buffer, we can rotate the buffers. 430 */ 431 if (d->bd_hbuf) 432 /* 433 * We filled up the buffer in between 434 * getting the timeout and arriving 435 * here, so we don't need to rotate. 436 */ 437 break; 438 439 if (d->bd_slen == 0) { 440 crit_exit(); 441 return(0); 442 } 443 ROTATE_BUFFERS(d); 444 break; 445 } 446 } 447 /* 448 * At this point, we know we have something in the hold slot. 449 */ 450 crit_exit(); 451 452 /* 453 * Move data from hold buffer into user space. 454 * We know the entire buffer is transferred since 455 * we checked above that the read buffer is bpf_bufsize bytes. 456 */ 457 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 458 459 crit_enter(); 460 d->bd_fbuf = d->bd_hbuf; 461 d->bd_hbuf = NULL; 462 d->bd_hlen = 0; 463 crit_exit(); 464 465 return(error); 466 } 467 468 469 /* 470 * If there are processes sleeping on this descriptor, wake them up. 471 */ 472 static void 473 bpf_wakeup(struct bpf_d *d) 474 { 475 if (d->bd_state == BPF_WAITING) { 476 callout_stop(&d->bd_callout); 477 d->bd_state = BPF_IDLE; 478 } 479 wakeup(d); 480 if (d->bd_async && d->bd_sig && d->bd_sigio) 481 pgsigio(d->bd_sigio, d->bd_sig, 0); 482 483 selwakeup(&d->bd_sel); 484 /* XXX */ 485 d->bd_sel.si_pid = 0; 486 } 487 488 static void 489 bpf_timed_out(void *arg) 490 { 491 struct bpf_d *d = (struct bpf_d *)arg; 492 493 crit_enter(); 494 if (d->bd_state == BPF_WAITING) { 495 d->bd_state = BPF_TIMED_OUT; 496 if (d->bd_slen != 0) 497 bpf_wakeup(d); 498 } 499 crit_exit(); 500 } 501 502 static int 503 bpfwrite(dev_t dev, struct uio *uio, int ioflag) 504 { 505 struct bpf_d *d = dev->si_drv1; 506 struct ifnet *ifp; 507 struct mbuf *m; 508 int error; 509 static struct sockaddr dst; 510 int datlen; 511 512 if (d->bd_bif == NULL) 513 return(ENXIO); 514 515 ifp = d->bd_bif->bif_ifp; 516 517 if (uio->uio_resid == 0) 518 return(0); 519 520 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen); 521 if (error) 522 return(error); 523 524 if (datlen > ifp->if_mtu) 525 return(EMSGSIZE); 526 527 if (d->bd_hdrcmplt) 528 dst.sa_family = pseudo_AF_HDRCMPLT; 529 530 crit_enter(); 531 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)NULL); 532 crit_exit(); 533 /* 534 * The driver frees the mbuf. 535 */ 536 return(error); 537 } 538 539 /* 540 * Reset a descriptor by flushing its packet buffer and clearing the 541 * receive and drop counts. Should be called at splimp. 542 */ 543 static void 544 reset_d(struct bpf_d *d) 545 { 546 if (d->bd_hbuf) { 547 /* Free the hold buffer. */ 548 d->bd_fbuf = d->bd_hbuf; 549 d->bd_hbuf = NULL; 550 } 551 d->bd_slen = 0; 552 d->bd_hlen = 0; 553 d->bd_rcount = 0; 554 d->bd_dcount = 0; 555 } 556 557 /* 558 * FIONREAD Check for read packet available. 559 * SIOCGIFADDR Get interface address - convenient hook to driver. 560 * BIOCGBLEN Get buffer len [for read()]. 561 * BIOCSETF Set ethernet read filter. 562 * BIOCFLUSH Flush read packet buffer. 563 * BIOCPROMISC Put interface into promiscuous mode. 564 * BIOCGDLT Get link layer type. 565 * BIOCGETIF Get interface name. 566 * BIOCSETIF Set interface. 567 * BIOCSRTIMEOUT Set read timeout. 568 * BIOCGRTIMEOUT Get read timeout. 569 * BIOCGSTATS Get packet stats. 570 * BIOCIMMEDIATE Set immediate mode. 571 * BIOCVERSION Get filter language version. 572 * BIOCGHDRCMPLT Get "header already complete" flag 573 * BIOCSHDRCMPLT Set "header already complete" flag 574 * BIOCGSEESENT Get "see packets sent" flag 575 * BIOCSSEESENT Set "see packets sent" flag 576 */ 577 /* ARGSUSED */ 578 static int 579 bpfioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td) 580 { 581 struct bpf_d *d = dev->si_drv1; 582 int error = 0; 583 584 crit_enter(); 585 if (d->bd_state == BPF_WAITING) 586 callout_stop(&d->bd_callout); 587 d->bd_state = BPF_IDLE; 588 crit_exit(); 589 590 switch (cmd) { 591 592 default: 593 error = EINVAL; 594 break; 595 596 /* 597 * Check for read packet available. 598 */ 599 case FIONREAD: 600 { 601 int n; 602 603 crit_enter(); 604 n = d->bd_slen; 605 if (d->bd_hbuf) 606 n += d->bd_hlen; 607 crit_exit(); 608 609 *(int *)addr = n; 610 break; 611 } 612 613 case SIOCGIFADDR: 614 { 615 struct ifnet *ifp; 616 617 if (d->bd_bif == NULL) 618 error = EINVAL; 619 else { 620 ifp = d->bd_bif->bif_ifp; 621 error = (*ifp->if_ioctl)(ifp, cmd, addr, 622 td->td_proc->p_ucred); 623 } 624 break; 625 } 626 627 /* 628 * Get buffer len [for read()]. 629 */ 630 case BIOCGBLEN: 631 *(u_int *)addr = d->bd_bufsize; 632 break; 633 634 /* 635 * Set buffer length. 636 */ 637 case BIOCSBLEN: 638 if (d->bd_bif != 0) 639 error = EINVAL; 640 else { 641 u_int size = *(u_int *)addr; 642 643 if (size > bpf_maxbufsize) 644 *(u_int *)addr = size = bpf_maxbufsize; 645 else if (size < BPF_MINBUFSIZE) 646 *(u_int *)addr = size = BPF_MINBUFSIZE; 647 d->bd_bufsize = size; 648 } 649 break; 650 651 /* 652 * Set link layer read filter. 653 */ 654 case BIOCSETF: 655 error = bpf_setf(d, (struct bpf_program *)addr); 656 break; 657 658 /* 659 * Flush read packet buffer. 660 */ 661 case BIOCFLUSH: 662 crit_enter(); 663 reset_d(d); 664 crit_exit(); 665 break; 666 667 /* 668 * Put interface into promiscuous mode. 669 */ 670 case BIOCPROMISC: 671 if (d->bd_bif == NULL) { 672 /* 673 * No interface attached yet. 674 */ 675 error = EINVAL; 676 break; 677 } 678 crit_enter(); 679 if (d->bd_promisc == 0) { 680 error = ifpromisc(d->bd_bif->bif_ifp, 1); 681 if (error == 0) 682 d->bd_promisc = 1; 683 } 684 crit_exit(); 685 break; 686 687 /* 688 * Get device parameters. 689 */ 690 case BIOCGDLT: 691 if (d->bd_bif == NULL) 692 error = EINVAL; 693 else 694 *(u_int *)addr = d->bd_bif->bif_dlt; 695 break; 696 697 /* 698 * Get a list of supported data link types. 699 */ 700 case BIOCGDLTLIST: 701 if (d->bd_bif == NULL) 702 error = EINVAL; 703 else 704 error = bpf_getdltlist(d, (struct bpf_dltlist *)addr); 705 break; 706 707 /* 708 * Set data link type. 709 */ 710 case BIOCSDLT: 711 if (d->bd_bif == NULL) 712 error = EINVAL; 713 else 714 error = bpf_setdlt(d, *(u_int *)addr); 715 break; 716 717 /* 718 * Get interface name. 719 */ 720 case BIOCGETIF: 721 if (d->bd_bif == NULL) { 722 error = EINVAL; 723 } else { 724 struct ifnet *const ifp = d->bd_bif->bif_ifp; 725 struct ifreq *const ifr = (struct ifreq *)addr; 726 727 strlcpy(ifr->ifr_name, ifp->if_xname, 728 sizeof ifr->ifr_name); 729 } 730 break; 731 732 /* 733 * Set interface. 734 */ 735 case BIOCSETIF: 736 error = bpf_setif(d, (struct ifreq *)addr); 737 break; 738 739 /* 740 * Set read timeout. 741 */ 742 case BIOCSRTIMEOUT: 743 { 744 struct timeval *tv = (struct timeval *)addr; 745 746 /* 747 * Subtract 1 tick from tvtohz() since this isn't 748 * a one-shot timer. 749 */ 750 if ((error = itimerfix(tv)) == 0) 751 d->bd_rtout = tvtohz_low(tv); 752 break; 753 } 754 755 /* 756 * Get read timeout. 757 */ 758 case BIOCGRTIMEOUT: 759 { 760 struct timeval *tv = (struct timeval *)addr; 761 762 tv->tv_sec = d->bd_rtout / hz; 763 tv->tv_usec = (d->bd_rtout % hz) * tick; 764 break; 765 } 766 767 /* 768 * Get packet stats. 769 */ 770 case BIOCGSTATS: 771 { 772 struct bpf_stat *bs = (struct bpf_stat *)addr; 773 774 bs->bs_recv = d->bd_rcount; 775 bs->bs_drop = d->bd_dcount; 776 break; 777 } 778 779 /* 780 * Set immediate mode. 781 */ 782 case BIOCIMMEDIATE: 783 d->bd_immediate = *(u_int *)addr; 784 break; 785 786 case BIOCVERSION: 787 { 788 struct bpf_version *bv = (struct bpf_version *)addr; 789 790 bv->bv_major = BPF_MAJOR_VERSION; 791 bv->bv_minor = BPF_MINOR_VERSION; 792 break; 793 } 794 795 /* 796 * Get "header already complete" flag 797 */ 798 case BIOCGHDRCMPLT: 799 *(u_int *)addr = d->bd_hdrcmplt; 800 break; 801 802 /* 803 * Set "header already complete" flag 804 */ 805 case BIOCSHDRCMPLT: 806 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 807 break; 808 809 /* 810 * Get "see sent packets" flag 811 */ 812 case BIOCGSEESENT: 813 *(u_int *)addr = d->bd_seesent; 814 break; 815 816 /* 817 * Set "see sent packets" flag 818 */ 819 case BIOCSSEESENT: 820 d->bd_seesent = *(u_int *)addr; 821 break; 822 823 case FIONBIO: /* Non-blocking I/O */ 824 break; 825 826 case FIOASYNC: /* Send signal on receive packets */ 827 d->bd_async = *(int *)addr; 828 break; 829 830 case FIOSETOWN: 831 error = fsetown(*(int *)addr, &d->bd_sigio); 832 break; 833 834 case FIOGETOWN: 835 *(int *)addr = fgetown(d->bd_sigio); 836 break; 837 838 /* This is deprecated, FIOSETOWN should be used instead. */ 839 case TIOCSPGRP: 840 error = fsetown(-(*(int *)addr), &d->bd_sigio); 841 break; 842 843 /* This is deprecated, FIOGETOWN should be used instead. */ 844 case TIOCGPGRP: 845 *(int *)addr = -fgetown(d->bd_sigio); 846 break; 847 848 case BIOCSRSIG: /* Set receive signal */ 849 { 850 u_int sig; 851 852 sig = *(u_int *)addr; 853 854 if (sig >= NSIG) 855 error = EINVAL; 856 else 857 d->bd_sig = sig; 858 break; 859 } 860 case BIOCGRSIG: 861 *(u_int *)addr = d->bd_sig; 862 break; 863 } 864 return(error); 865 } 866 867 /* 868 * Set d's packet filter program to fp. If this file already has a filter, 869 * free it and replace it. Returns EINVAL for bogus requests. 870 */ 871 static int 872 bpf_setf(struct bpf_d *d, struct bpf_program *fp) 873 { 874 struct bpf_insn *fcode, *old; 875 u_int flen, size; 876 877 old = d->bd_filter; 878 if (fp->bf_insns == NULL) { 879 if (fp->bf_len != 0) 880 return(EINVAL); 881 crit_enter(); 882 d->bd_filter = NULL; 883 reset_d(d); 884 crit_exit(); 885 if (old != 0) 886 free(old, M_BPF); 887 return(0); 888 } 889 flen = fp->bf_len; 890 if (flen > BPF_MAXINSNS) 891 return(EINVAL); 892 893 size = flen * sizeof *fp->bf_insns; 894 fcode = (struct bpf_insn *)malloc(size, M_BPF, M_WAITOK); 895 if (copyin(fp->bf_insns, fcode, size) == 0 && 896 bpf_validate(fcode, (int)flen)) { 897 crit_enter(); 898 d->bd_filter = fcode; 899 reset_d(d); 900 crit_exit(); 901 if (old != 0) 902 free(old, M_BPF); 903 904 return(0); 905 } 906 free(fcode, M_BPF); 907 return(EINVAL); 908 } 909 910 /* 911 * Detach a file from its current interface (if attached at all) and attach 912 * to the interface indicated by the name stored in ifr. 913 * Return an errno or 0. 914 */ 915 static int 916 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 917 { 918 struct bpf_if *bp; 919 int error; 920 struct ifnet *theywant; 921 922 theywant = ifunit(ifr->ifr_name); 923 if (theywant == NULL) 924 return(ENXIO); 925 926 /* 927 * Look through attached interfaces for the named one. 928 */ 929 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 930 struct ifnet *ifp = bp->bif_ifp; 931 932 if (ifp == NULL || ifp != theywant) 933 continue; 934 /* skip additional entry */ 935 if (bp->bif_driverp != &ifp->if_bpf) 936 continue; 937 /* 938 * We found the requested interface. 939 * If it's not up, return an error. 940 * Allocate the packet buffers if we need to. 941 * If we're already attached to requested interface, 942 * just flush the buffer. 943 */ 944 if (!(ifp->if_flags & IFF_UP)) 945 return(ENETDOWN); 946 947 if (d->bd_sbuf == NULL) { 948 error = bpf_allocbufs(d); 949 if (error != 0) 950 return(error); 951 } 952 crit_enter(); 953 if (bp != d->bd_bif) { 954 if (d->bd_bif != NULL) { 955 /* 956 * Detach if attached to something else. 957 */ 958 bpf_detachd(d); 959 } 960 961 bpf_attachd(d, bp); 962 } 963 reset_d(d); 964 crit_exit(); 965 return(0); 966 } 967 968 /* Not found. */ 969 return(ENXIO); 970 } 971 972 /* 973 * Support for select() and poll() system calls 974 * 975 * Return true iff the specific operation will not block indefinitely. 976 * Otherwise, return false but make a note that a selwakeup() must be done. 977 */ 978 int 979 bpfpoll(dev_t dev, int events, struct thread *td) 980 { 981 struct bpf_d *d; 982 int revents; 983 984 d = dev->si_drv1; 985 if (d->bd_bif == NULL) 986 return(ENXIO); 987 988 revents = events & (POLLOUT | POLLWRNORM); 989 crit_enter(); 990 if (events & (POLLIN | POLLRDNORM)) { 991 /* 992 * An imitation of the FIONREAD ioctl code. 993 * XXX not quite. An exact imitation: 994 * if (d->b_slen != 0 || 995 * (d->bd_hbuf != NULL && d->bd_hlen != 0) 996 */ 997 if (d->bd_hlen != 0 || 998 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) && 999 d->bd_slen != 0)) 1000 revents |= events & (POLLIN | POLLRDNORM); 1001 else { 1002 selrecord(td, &d->bd_sel); 1003 /* Start the read timeout if necessary. */ 1004 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1005 callout_reset(&d->bd_callout, d->bd_rtout, 1006 bpf_timed_out, d); 1007 d->bd_state = BPF_WAITING; 1008 } 1009 } 1010 } 1011 crit_exit(); 1012 return(revents); 1013 } 1014 1015 /* 1016 * Process the packet pkt of length pktlen. The packet is parsed 1017 * by each listener's filter, and if accepted, stashed into the 1018 * corresponding buffer. 1019 */ 1020 void 1021 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1022 { 1023 struct bpf_d *d; 1024 u_int slen; 1025 1026 /* 1027 * Note that the ipl does not have to be raised at this point. 1028 * The only problem that could arise here is that if two different 1029 * interfaces shared any data. This is not the case. 1030 */ 1031 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1032 ++d->bd_rcount; 1033 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); 1034 if (slen != 0) 1035 catchpacket(d, pkt, pktlen, slen, ovbcopy); 1036 } 1037 } 1038 1039 /* 1040 * Copy data from an mbuf chain into a buffer. This code is derived 1041 * from m_copydata in sys/uipc_mbuf.c. 1042 */ 1043 static void 1044 bpf_mcopy(const void *src_arg, void *dst_arg, size_t len) 1045 { 1046 const struct mbuf *m; 1047 u_int count; 1048 u_char *dst; 1049 1050 m = src_arg; 1051 dst = dst_arg; 1052 while (len > 0) { 1053 if (m == NULL) 1054 panic("bpf_mcopy"); 1055 count = min(m->m_len, len); 1056 bcopy(mtod(m, void *), dst, count); 1057 m = m->m_next; 1058 dst += count; 1059 len -= count; 1060 } 1061 } 1062 1063 /* 1064 * Process the packet in the mbuf chain m. The packet is parsed by each 1065 * listener's filter, and if accepted, stashed into the corresponding 1066 * buffer. 1067 */ 1068 void 1069 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1070 { 1071 struct bpf_d *d; 1072 u_int pktlen, slen; 1073 struct mbuf *m0; 1074 1075 /* Don't compute pktlen, if no descriptor is attached. */ 1076 if (SLIST_EMPTY(&bp->bif_dlist)) 1077 return; 1078 1079 pktlen = 0; 1080 for (m0 = m; m0 != NULL; m0 = m0->m_next) 1081 pktlen += m0->m_len; 1082 1083 SLIST_FOREACH(d, &bp->bif_dlist, bd_next) { 1084 if (!d->bd_seesent && (m->m_pkthdr.rcvif == NULL)) 1085 continue; 1086 ++d->bd_rcount; 1087 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); 1088 if (slen != 0) 1089 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); 1090 } 1091 } 1092 1093 void 1094 bpf_mtap_family(struct bpf_if *bp, struct mbuf *m, sa_family_t family) 1095 { 1096 u_int family4; 1097 1098 KKASSERT(family != AF_UNSPEC); 1099 1100 family4 = (u_int)family; 1101 bpf_ptap(bp, m, &family4, sizeof(family4)); 1102 } 1103 1104 /* 1105 * Process the packet in the mbuf chain m with the header in m prepended. 1106 * The packet is parsed by each listener's filter, and if accepted, 1107 * stashed into the corresponding buffer. 1108 */ 1109 void 1110 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen) 1111 { 1112 struct mbuf mb; 1113 1114 /* 1115 * Craft on-stack mbuf suitable for passing to bpf_mtap. 1116 * Note that we cut corners here; we only setup what's 1117 * absolutely needed--this mbuf should never go anywhere else. 1118 */ 1119 mb.m_next = m; 1120 mb.m_data = __DECONST(void *, data); /* LINTED */ 1121 mb.m_len = dlen; 1122 1123 bpf_mtap(bp, &mb); 1124 } 1125 1126 /* 1127 * Move the packet data from interface memory (pkt) into the 1128 * store buffer. Return 1 if it's time to wakeup a listener (buffer full), 1129 * otherwise 0. "copy" is the routine called to do the actual data 1130 * transfer. bcopy is passed in to copy contiguous chunks, while 1131 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1132 * pkt is really an mbuf. 1133 */ 1134 static void 1135 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1136 void (*cpfn)(const void *, void *, size_t)) 1137 { 1138 struct bpf_hdr *hp; 1139 int totlen, curlen; 1140 int hdrlen = d->bd_bif->bif_hdrlen; 1141 /* 1142 * Figure out how many bytes to move. If the packet is 1143 * greater or equal to the snapshot length, transfer that 1144 * much. Otherwise, transfer the whole packet (unless 1145 * we hit the buffer size limit). 1146 */ 1147 totlen = hdrlen + min(snaplen, pktlen); 1148 if (totlen > d->bd_bufsize) 1149 totlen = d->bd_bufsize; 1150 1151 /* 1152 * Round up the end of the previous packet to the next longword. 1153 */ 1154 curlen = BPF_WORDALIGN(d->bd_slen); 1155 if (curlen + totlen > d->bd_bufsize) { 1156 /* 1157 * This packet will overflow the storage buffer. 1158 * Rotate the buffers if we can, then wakeup any 1159 * pending reads. 1160 */ 1161 if (d->bd_fbuf == NULL) { 1162 /* 1163 * We haven't completed the previous read yet, 1164 * so drop the packet. 1165 */ 1166 ++d->bd_dcount; 1167 return; 1168 } 1169 ROTATE_BUFFERS(d); 1170 bpf_wakeup(d); 1171 curlen = 0; 1172 } 1173 else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) 1174 /* 1175 * Immediate mode is set, or the read timeout has 1176 * already expired during a select call. A packet 1177 * arrived, so the reader should be woken up. 1178 */ 1179 bpf_wakeup(d); 1180 1181 /* 1182 * Append the bpf header. 1183 */ 1184 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1185 microtime(&hp->bh_tstamp); 1186 hp->bh_datalen = pktlen; 1187 hp->bh_hdrlen = hdrlen; 1188 /* 1189 * Copy the packet data into the store buffer and update its length. 1190 */ 1191 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1192 d->bd_slen = curlen + totlen; 1193 } 1194 1195 /* 1196 * Initialize all nonzero fields of a descriptor. 1197 */ 1198 static int 1199 bpf_allocbufs(struct bpf_d *d) 1200 { 1201 d->bd_fbuf = malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1202 if (d->bd_fbuf == NULL) 1203 return(ENOBUFS); 1204 1205 d->bd_sbuf = malloc(d->bd_bufsize, M_BPF, M_WAITOK); 1206 if (d->bd_sbuf == NULL) { 1207 free(d->bd_fbuf, M_BPF); 1208 return(ENOBUFS); 1209 } 1210 d->bd_slen = 0; 1211 d->bd_hlen = 0; 1212 return(0); 1213 } 1214 1215 /* 1216 * Free buffers currently in use by a descriptor. 1217 * Called on close. 1218 */ 1219 static void 1220 bpf_freed(struct bpf_d *d) 1221 { 1222 /* 1223 * We don't need to lock out interrupts since this descriptor has 1224 * been detached from its interface and it yet hasn't been marked 1225 * free. 1226 */ 1227 if (d->bd_sbuf != NULL) { 1228 free(d->bd_sbuf, M_BPF); 1229 if (d->bd_hbuf != NULL) 1230 free(d->bd_hbuf, M_BPF); 1231 if (d->bd_fbuf != NULL) 1232 free(d->bd_fbuf, M_BPF); 1233 } 1234 if (d->bd_filter) 1235 free(d->bd_filter, M_BPF); 1236 } 1237 1238 /* 1239 * Attach an interface to bpf. ifp is a pointer to the structure 1240 * defining the interface to be attached, dlt is the link layer type, 1241 * and hdrlen is the fixed size of the link header (variable length 1242 * headers are not yet supported). 1243 */ 1244 void 1245 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1246 { 1247 bpfattach_dlt(ifp, dlt, hdrlen, &ifp->if_bpf); 1248 } 1249 1250 void 1251 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1252 { 1253 struct bpf_if *bp; 1254 1255 bp = malloc(sizeof *bp, M_BPF, M_WAITOK | M_ZERO); 1256 1257 SLIST_INIT(&bp->bif_dlist); 1258 bp->bif_ifp = ifp; 1259 bp->bif_dlt = dlt; 1260 bp->bif_driverp = driverp; 1261 *bp->bif_driverp = NULL; 1262 1263 bp->bif_next = bpf_iflist; 1264 bpf_iflist = bp; 1265 1266 /* 1267 * Compute the length of the bpf header. This is not necessarily 1268 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1269 * that the network layer header begins on a longword boundary (for 1270 * performance reasons and to alleviate alignment restrictions). 1271 */ 1272 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1273 1274 if (bootverbose) 1275 if_printf(ifp, "bpf attached\n"); 1276 } 1277 1278 /* 1279 * Detach bpf from an interface. This involves detaching each descriptor 1280 * associated with the interface, and leaving bd_bif NULL. Notify each 1281 * descriptor as it's detached so that any sleepers wake up and get 1282 * ENXIO. 1283 */ 1284 void 1285 bpfdetach(struct ifnet *ifp) 1286 { 1287 struct bpf_if *bp, *bp_prev; 1288 struct bpf_d *d; 1289 1290 crit_enter(); 1291 1292 /* Locate BPF interface information */ 1293 bp_prev = NULL; 1294 for (bp = bpf_iflist; bp != NULL; bp = bp->bif_next) { 1295 if (ifp == bp->bif_ifp) 1296 break; 1297 bp_prev = bp; 1298 } 1299 1300 /* Interface wasn't attached */ 1301 if (bp->bif_ifp == NULL) { 1302 crit_exit(); 1303 printf("bpfdetach: %s was not attached\n", ifp->if_xname); 1304 return; 1305 } 1306 1307 while ((d = SLIST_FIRST(&bp->bif_dlist)) != NULL) { 1308 bpf_detachd(d); 1309 bpf_wakeup(d); 1310 } 1311 1312 if (bp_prev != NULL) 1313 bp_prev->bif_next = bp->bif_next; 1314 else 1315 bpf_iflist = bp->bif_next; 1316 1317 free(bp, M_BPF); 1318 1319 crit_exit(); 1320 } 1321 1322 /* 1323 * Get a list of available data link type of the interface. 1324 */ 1325 static int 1326 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 1327 { 1328 int n, error; 1329 struct ifnet *ifp; 1330 struct bpf_if *bp; 1331 1332 ifp = d->bd_bif->bif_ifp; 1333 n = 0; 1334 error = 0; 1335 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 1336 if (bp->bif_ifp != ifp) 1337 continue; 1338 if (bfl->bfl_list != NULL) { 1339 if (n >= bfl->bfl_len) { 1340 return (ENOMEM); 1341 } 1342 error = copyout(&bp->bif_dlt, 1343 bfl->bfl_list + n, sizeof(u_int)); 1344 } 1345 n++; 1346 } 1347 bfl->bfl_len = n; 1348 return(error); 1349 } 1350 1351 /* 1352 * Set the data link type of a BPF instance. 1353 */ 1354 static int 1355 bpf_setdlt(struct bpf_d *d, u_int dlt) 1356 { 1357 int error, opromisc; 1358 struct ifnet *ifp; 1359 struct bpf_if *bp; 1360 1361 if (d->bd_bif->bif_dlt == dlt) 1362 return (0); 1363 ifp = d->bd_bif->bif_ifp; 1364 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 1365 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 1366 break; 1367 } 1368 if (bp != NULL) { 1369 opromisc = d->bd_promisc; 1370 crit_enter(); 1371 bpf_detachd(d); 1372 bpf_attachd(d, bp); 1373 reset_d(d); 1374 if (opromisc) { 1375 error = ifpromisc(bp->bif_ifp, 1); 1376 if (error) 1377 if_printf(bp->bif_ifp, 1378 "bpf_setdlt: ifpromisc failed (%d)\n", 1379 error); 1380 else 1381 d->bd_promisc = 1; 1382 } 1383 crit_exit(); 1384 } 1385 return(bp == NULL ? EINVAL : 0); 1386 } 1387 1388 static void 1389 bpf_drvinit(void *unused) 1390 { 1391 cdevsw_add(&bpf_cdevsw, 0, 0); 1392 } 1393 1394 SYSINIT(bpfdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,bpf_drvinit,NULL) 1395 1396 #else /* !BPF */ 1397 /* 1398 * NOP stubs to allow bpf-using drivers to load and function. 1399 * 1400 * A 'better' implementation would allow the core bpf functionality 1401 * to be loaded at runtime. 1402 */ 1403 1404 void 1405 bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1406 { 1407 } 1408 1409 void 1410 bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1411 { 1412 } 1413 1414 void 1415 bpf_ptap(struct bpf_if *bp, struct mbuf *m, const void *data, u_int dlen) 1416 { 1417 } 1418 1419 void 1420 bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen) 1421 { 1422 } 1423 1424 void 1425 bpfattach_dlt(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 1426 { 1427 } 1428 1429 void 1430 bpfdetach(struct ifnet *ifp) 1431 { 1432 } 1433 1434 u_int 1435 bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen) 1436 { 1437 return -1; /* "no filter" behaviour */ 1438 } 1439 1440 #endif /* !BPF */ 1441