1 /*- 2 * Copyright (c) 1990-1991 The Regents of the University of California. 3 * 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 * from: @(#)bpf.c 7.5 (Berkeley) 7/15/91 39 * $Id: bpf.c,v 1.5 1993/05/18 18:19:50 cgd Exp $ 40 */ 41 42 #include "bpfilter.h" 43 44 #if NBPFILTER > 0 45 46 #ifndef __386BSD__ 47 #define __386BSD__ 48 #endif 49 50 #include <sys/param.h> 51 #include <sys/systm.h> 52 #include <sys/mbuf.h> 53 #include <sys/buf.h> 54 #include <sys/dir.h> 55 #include <sys/time.h> 56 #include <sys/proc.h> 57 #include <sys/user.h> 58 #include <sys/ioctl.h> 59 #include <sys/select.h> 60 61 #include <sys/file.h> 62 #if defined(sparc) && BSD < 199103 63 #include <sys/stream.h> 64 #endif 65 #include <sys/tty.h> 66 #include <sys/uio.h> 67 68 #include <sys/protosw.h> 69 #include <sys/socket.h> 70 #include <net/if.h> 71 72 #include <net/bpf.h> 73 #include <net/bpfdesc.h> 74 75 #include <sys/errno.h> 76 77 #include <netinet/in.h> 78 #include <netinet/if_ether.h> 79 #include <sys/kernel.h> 80 81 /* 82 * Older BSDs don't have kernel malloc. 83 */ 84 #if BSD < 199103 85 extern bcopy(); 86 static caddr_t bpf_alloc(); 87 #include <net/bpf_compat.h> 88 #define BPF_BUFSIZE (MCLBYTES-8) 89 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio) 90 #else 91 #define BPF_BUFSIZE 4096 92 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio) 93 #endif 94 95 #define PRINET 26 /* interruptible */ 96 97 /* 98 * The default read buffer size is patchable. 99 */ 100 int bpf_bufsize = BPF_BUFSIZE; 101 102 /* 103 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 104 * bpf_dtab holds the descriptors, indexed by minor device # 105 */ 106 struct bpf_if *bpf_iflist; 107 struct bpf_d bpf_dtab[NBPFILTER]; 108 109 static void bpf_ifname(); 110 static void catchpacket(); 111 static void bpf_freed(); 112 static int bpf_setif(); 113 static int bpf_initd(); 114 static int bpf_allocbufs(); 115 116 static int 117 bpf_movein(uio, linktype, mp, sockp) 118 register struct uio *uio; 119 int linktype; 120 register struct mbuf **mp; 121 register struct sockaddr *sockp; 122 { 123 struct mbuf *m; 124 int error; 125 int len; 126 int hlen; 127 128 /* 129 * Build a sockaddr based on the data link layer type. 130 * We do this at this level because the ethernet header 131 * is copied directly into the data field of the sockaddr. 132 * In the case of SLIP, there is no header and the packet 133 * is forwarded as is. 134 * Also, we are careful to leave room at the front of the mbuf 135 * for the link level header. 136 */ 137 switch (linktype) { 138 139 case DLT_SLIP: 140 sockp->sa_family = AF_INET; 141 hlen = 0; 142 break; 143 144 case DLT_EN10MB: 145 sockp->sa_family = AF_UNSPEC; 146 /* XXX Would MAXLINKHDR be better? */ 147 hlen = sizeof(struct ether_header); 148 break; 149 150 case DLT_FDDI: 151 sockp->sa_family = AF_UNSPEC; 152 /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */ 153 hlen = 24; 154 break; 155 156 case DLT_NULL: 157 sockp->sa_family = AF_UNSPEC; 158 hlen = 0; 159 break; 160 161 default: 162 return (EIO); 163 } 164 165 len = uio->uio_resid; 166 if ((unsigned)len > MCLBYTES) 167 return (EIO); 168 169 MGET(m, M_WAIT, MT_DATA); 170 if (m == 0) 171 return (ENOBUFS); 172 if (len > MLEN) { 173 #if BSD >= 199103 174 MCLGET(m, M_WAIT); 175 if ((m->m_flags & M_EXT) == 0) { 176 #else 177 MCLGET(m); 178 if (m->m_len != MCLBYTES) { 179 #endif 180 error = ENOBUFS; 181 goto bad; 182 } 183 } 184 m->m_len = len; 185 *mp = m; 186 /* 187 * Make room for link header. 188 */ 189 if (hlen != 0) { 190 m->m_len -= hlen; 191 #if BSD >= 199103 192 m->m_data += hlen; /* XXX */ 193 #else 194 m->m_off += hlen; 195 #endif 196 error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio); 197 if (error) 198 goto bad; 199 } 200 error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio); 201 if (!error) 202 return (0); 203 bad: 204 m_freem(m); 205 return (error); 206 } 207 208 /* 209 * Attach file to the bpf interface, i.e. make d listen on bp. 210 * Must be called at splimp. 211 */ 212 static void 213 bpf_attachd(d, bp) 214 struct bpf_d *d; 215 struct bpf_if *bp; 216 { 217 /* 218 * Point d at bp, and add d to the interface's list of listeners. 219 * Finally, point the driver's bpf cookie at the interface so 220 * it will divert packets to bpf. 221 */ 222 d->bd_bif = bp; 223 d->bd_next = bp->bif_dlist; 224 bp->bif_dlist = d; 225 226 *bp->bif_driverp = bp; 227 } 228 229 /* 230 * Detach a file from its interface. 231 */ 232 static void 233 bpf_detachd(d) 234 struct bpf_d *d; 235 { 236 struct bpf_d **p; 237 struct bpf_if *bp; 238 239 bp = d->bd_bif; 240 /* 241 * Check if this descriptor had requested promiscuous mode. 242 * If so, turn it off. 243 */ 244 if (d->bd_promisc) { 245 d->bd_promisc = 0; 246 if (ifpromisc(bp->bif_ifp, 0)) 247 /* 248 * Something is really wrong if we were able to put 249 * the driver into promiscuous mode, but can't 250 * take it out. 251 */ 252 panic("bpf: ifpromisc failed"); 253 } 254 /* Remove d from the interface's descriptor list. */ 255 p = &bp->bif_dlist; 256 while (*p != d) { 257 p = &(*p)->bd_next; 258 if (*p == 0) 259 panic("bpf_detachd: descriptor not in list"); 260 } 261 *p = (*p)->bd_next; 262 if (bp->bif_dlist == 0) 263 /* 264 * Let the driver know that there are no more listeners. 265 */ 266 *d->bd_bif->bif_driverp = 0; 267 d->bd_bif = 0; 268 } 269 270 271 /* 272 * Mark a descriptor free by making it point to itself. 273 * This is probably cheaper than marking with a constant since 274 * the address should be in a register anyway. 275 */ 276 #define D_ISFREE(d) ((d) == (d)->bd_next) 277 #define D_MARKFREE(d) ((d)->bd_next = (d)) 278 #define D_MARKUSED(d) ((d)->bd_next = 0) 279 280 /* 281 * Open ethernet device. Returns ENXIO for illegal minor device number, 282 * EBUSY if file is open by another process. 283 */ 284 /* ARGSUSED */ 285 int 286 bpfopen(dev, flag) 287 dev_t dev; 288 int flag; 289 { 290 register struct bpf_d *d; 291 292 if (minor(dev) >= NBPFILTER) 293 return (ENXIO); 294 /* 295 * Each minor can be opened by only one process. If the requested 296 * minor is in use, return EBUSY. 297 */ 298 d = &bpf_dtab[minor(dev)]; 299 if (!D_ISFREE(d)) 300 return (EBUSY); 301 302 /* Mark "free" and do most initialization. */ 303 bzero((char *)d, sizeof(*d)); 304 d->bd_bufsize = bpf_bufsize; 305 306 return (0); 307 } 308 309 /* 310 * Close the descriptor by detaching it from its interface, 311 * deallocating its buffers, and marking it free. 312 */ 313 /* ARGSUSED */ 314 int 315 bpfclose(dev, flag) 316 dev_t dev; 317 int flag; 318 { 319 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 320 register int s; 321 322 s = splimp(); 323 if (d->bd_bif) 324 bpf_detachd(d); 325 splx(s); 326 bpf_freed(d); 327 328 return (0); 329 } 330 331 /* 332 * Support for SunOS, which does not have tsleep. 333 */ 334 #if BSD < 199103 335 static 336 bpf_timeout(arg) 337 caddr_t arg; 338 { 339 struct bpf_d *d = (struct bpf_d *)arg; 340 d->bd_timedout = 1; 341 wakeup(arg); 342 } 343 344 #define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan) 345 346 int 347 bpf_sleep(d) 348 register struct bpf_d *d; 349 { 350 register int rto = d->bd_rtout; 351 register int st; 352 353 if (rto != 0) { 354 d->bd_timedout = 0; 355 timeout(bpf_timeout, (caddr_t)d, rto); 356 } 357 st = sleep((caddr_t)d, PRINET|PCATCH); 358 if (rto != 0) { 359 if (d->bd_timedout == 0) 360 untimeout(bpf_timeout, (caddr_t)d); 361 else if (st == 0) 362 return EWOULDBLOCK; 363 } 364 return (st != 0) ? EINTR : 0; 365 } 366 #else 367 #define BPF_SLEEP tsleep 368 #endif 369 370 /* 371 * Rotate the packet buffers in descriptor d. Move the store buffer 372 * into the hold slot, and the free buffer into the store slot. 373 * Zero the length of the new store buffer. 374 */ 375 #define ROTATE_BUFFERS(d) \ 376 (d)->bd_hbuf = (d)->bd_sbuf; \ 377 (d)->bd_hlen = (d)->bd_slen; \ 378 (d)->bd_sbuf = (d)->bd_fbuf; \ 379 (d)->bd_slen = 0; \ 380 (d)->bd_fbuf = 0; 381 /* 382 * bpfread - read next chunk of packets from buffers 383 */ 384 int 385 bpfread(dev, uio) 386 dev_t dev; 387 register struct uio *uio; 388 { 389 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 390 int error; 391 int s; 392 393 /* 394 * Restrict application to use a buffer the same size as 395 * as kernel buffers. 396 */ 397 if (uio->uio_resid != d->bd_bufsize) 398 return (EINVAL); 399 400 s = splimp(); 401 /* 402 * If the hold buffer is empty, then do a timed sleep, which 403 * ends when the timeout expires or when enough packets 404 * have arrived to fill the store buffer. 405 */ 406 while (d->bd_hbuf == 0) { 407 if (d->bd_immediate && d->bd_slen != 0) { 408 /* 409 * A packet(s) either arrived since the previous 410 * read or arrived while we were asleep. 411 * Rotate the buffers and return what's here. 412 */ 413 ROTATE_BUFFERS(d); 414 break; 415 } 416 error = BPF_SLEEP((caddr_t)d, PRINET|PCATCH, "bpf", 417 d->bd_rtout); 418 if (error == EINTR || error == ERESTART) { 419 splx(s); 420 return (error); 421 } 422 if (error == EWOULDBLOCK) { 423 /* 424 * On a timeout, return what's in the buffer, 425 * which may be nothing. If there is something 426 * in the store buffer, we can rotate the buffers. 427 */ 428 if (d->bd_hbuf) 429 /* 430 * We filled up the buffer in between 431 * getting the timeout and arriving 432 * here, so we don't need to rotate. 433 */ 434 break; 435 436 if (d->bd_slen == 0) { 437 splx(s); 438 return (0); 439 } 440 ROTATE_BUFFERS(d); 441 break; 442 } 443 } 444 /* 445 * At this point, we know we have something in the hold slot. 446 */ 447 splx(s); 448 449 /* 450 * Move data from hold buffer into user space. 451 * We know the entire buffer is transferred since 452 * we checked above that the read buffer is bpf_bufsize bytes. 453 */ 454 error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio); 455 456 s = splimp(); 457 d->bd_fbuf = d->bd_hbuf; 458 d->bd_hbuf = 0; 459 d->bd_hlen = 0; 460 splx(s); 461 462 return (error); 463 } 464 465 466 /* 467 * If there are processes sleeping on this descriptor, wake them up. 468 */ 469 static inline void 470 bpf_wakeup(d) 471 register struct bpf_d *d; 472 { 473 wakeup((caddr_t)d); 474 #if (BSD > 199103) || defined(__386BSD__) 475 selwakeup(&d->bd_sel); 476 /* XXX */ 477 d->bd_sel.si_pid = 0; 478 #else 479 if (d->bd_selproc) { 480 selwakeup(d->bd_selproc, (int)d->bd_selcoll); 481 d->bd_selcoll = 0; 482 d->bd_selproc = 0; 483 } 484 #endif 485 } 486 487 int 488 bpfwrite(dev, uio) 489 dev_t dev; 490 struct uio *uio; 491 { 492 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 493 struct ifnet *ifp; 494 struct mbuf *m; 495 int error, s; 496 static struct sockaddr dst; 497 498 if (d->bd_bif == 0) 499 return (ENXIO); 500 501 ifp = d->bd_bif->bif_ifp; 502 503 if (uio->uio_resid == 0) 504 return (0); 505 if (uio->uio_resid > ifp->if_mtu) 506 return (EMSGSIZE); 507 508 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst); 509 if (error) 510 return (error); 511 512 s = splnet(); 513 #if BSD >= 199103 514 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0); 515 #else 516 error = (*ifp->if_output)(ifp, m, &dst); 517 #endif 518 splx(s); 519 /* 520 * The driver frees the mbuf. 521 */ 522 return (error); 523 } 524 525 /* 526 * Reset a descriptor by flushing its packet buffer and clearing the 527 * receive and drop counts. Should be called at splimp. 528 */ 529 static void 530 reset_d(d) 531 struct bpf_d *d; 532 { 533 if (d->bd_hbuf) { 534 /* Free the hold buffer. */ 535 d->bd_fbuf = d->bd_hbuf; 536 d->bd_hbuf = 0; 537 } 538 d->bd_slen = 0; 539 d->bd_hlen = 0; 540 d->bd_rcount = 0; 541 d->bd_dcount = 0; 542 } 543 544 /* 545 * FIONREAD Check for read packet available. 546 * SIOCGIFADDR Get interface address - convenient hook to driver. 547 * BIOCGBLEN Get buffer len [for read()]. 548 * BIOCSETF Set ethernet read filter. 549 * BIOCFLUSH Flush read packet buffer. 550 * BIOCPROMISC Put interface into promiscuous mode. 551 * BIOCGDLT Get link layer type. 552 * BIOCGETIF Get interface name. 553 * BIOCSETIF Set interface. 554 * BIOCSRTIMEOUT Set read timeout. 555 * BIOCGRTIMEOUT Get read timeout. 556 * BIOCGSTATS Get packet stats. 557 * BIOCIMMEDIATE Set immediate mode. 558 * BIOCVERSION Get filter language version. 559 */ 560 /* ARGSUSED */ 561 int 562 bpfioctl(dev, cmd, addr, flag) 563 dev_t dev; 564 int cmd; 565 caddr_t addr; 566 int flag; 567 { 568 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 569 int s, error = 0; 570 571 switch (cmd) { 572 573 default: 574 error = EINVAL; 575 break; 576 577 /* 578 * Check for read packet available. 579 */ 580 case FIONREAD: 581 { 582 int n; 583 584 s = splimp(); 585 n = d->bd_slen; 586 if (d->bd_hbuf) 587 n += d->bd_hlen; 588 splx(s); 589 590 *(int *)addr = n; 591 break; 592 } 593 594 case SIOCGIFADDR: 595 { 596 struct ifnet *ifp; 597 598 if (d->bd_bif == 0) 599 error = EINVAL; 600 else { 601 ifp = d->bd_bif->bif_ifp; 602 error = (*ifp->if_ioctl)(ifp, cmd, addr); 603 } 604 break; 605 } 606 607 /* 608 * Get buffer len [for read()]. 609 */ 610 case BIOCGBLEN: 611 *(u_int *)addr = d->bd_bufsize; 612 break; 613 614 /* 615 * Set buffer length. 616 */ 617 case BIOCSBLEN: 618 #if BSD < 199103 619 error = EINVAL; 620 #else 621 if (d->bd_bif != 0) 622 error = EINVAL; 623 else { 624 register u_int size = *(u_int *)addr; 625 626 if (size > BPF_MAXBUFSIZE) 627 *(u_int *)addr = size = BPF_MAXBUFSIZE; 628 else if (size < BPF_MINBUFSIZE) 629 *(u_int *)addr = size = BPF_MINBUFSIZE; 630 d->bd_bufsize = size; 631 } 632 #endif 633 break; 634 635 /* 636 * Set link layer read filter. 637 */ 638 case BIOCSETF: 639 error = bpf_setf(d, (struct bpf_program *)addr); 640 break; 641 642 /* 643 * Flush read packet buffer. 644 */ 645 case BIOCFLUSH: 646 s = splimp(); 647 reset_d(d); 648 splx(s); 649 break; 650 651 /* 652 * Put interface into promiscuous mode. 653 */ 654 case BIOCPROMISC: 655 if (d->bd_bif == 0) { 656 /* 657 * No interface attached yet. 658 */ 659 error = EINVAL; 660 break; 661 } 662 s = splimp(); 663 if (d->bd_promisc == 0) { 664 error = ifpromisc(d->bd_bif->bif_ifp, 1); 665 if (error == 0) 666 d->bd_promisc = 1; 667 } 668 splx(s); 669 break; 670 671 /* 672 * Get device parameters. 673 */ 674 case BIOCGDLT: 675 if (d->bd_bif == 0) 676 error = EINVAL; 677 else 678 *(u_int *)addr = d->bd_bif->bif_dlt; 679 break; 680 681 /* 682 * Set interface name. 683 */ 684 case BIOCGETIF: 685 if (d->bd_bif == 0) 686 error = EINVAL; 687 else 688 bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr); 689 break; 690 691 /* 692 * Set interface. 693 */ 694 case BIOCSETIF: 695 error = bpf_setif(d, (struct ifreq *)addr); 696 break; 697 698 /* 699 * Set read timeout. 700 */ 701 case BIOCSRTIMEOUT: 702 { 703 struct timeval *tv = (struct timeval *)addr; 704 u_long msec; 705 706 /* Compute number of milliseconds. */ 707 msec = tv->tv_sec * 1000 + tv->tv_usec / 1000; 708 /* Scale milliseconds to ticks. Assume hard 709 clock has millisecond or greater resolution 710 (i.e. tick >= 1000). For 10ms hardclock, 711 tick/1000 = 10, so rtout<-msec/10. */ 712 d->bd_rtout = msec / (tick / 1000); 713 break; 714 } 715 716 /* 717 * Get read timeout. 718 */ 719 case BIOCGRTIMEOUT: 720 { 721 struct timeval *tv = (struct timeval *)addr; 722 u_long msec = d->bd_rtout; 723 724 msec *= tick / 1000; 725 tv->tv_sec = msec / 1000; 726 tv->tv_usec = msec % 1000; 727 break; 728 } 729 730 /* 731 * Get packet stats. 732 */ 733 case BIOCGSTATS: 734 { 735 struct bpf_stat *bs = (struct bpf_stat *)addr; 736 737 bs->bs_recv = d->bd_rcount; 738 bs->bs_drop = d->bd_dcount; 739 break; 740 } 741 742 /* 743 * Set immediate mode. 744 */ 745 case BIOCIMMEDIATE: 746 d->bd_immediate = *(u_int *)addr; 747 break; 748 749 case BIOCVERSION: 750 { 751 struct bpf_version *bv = (struct bpf_version *)addr; 752 753 bv->bv_major = BPF_MAJOR_VERSION; 754 bv->bv_minor = BPF_MINOR_VERSION; 755 break; 756 } 757 } 758 return (error); 759 } 760 761 /* 762 * Set d's packet filter program to fp. If this file already has a filter, 763 * free it and replace it. Returns EINVAL for bogus requests. 764 */ 765 int 766 bpf_setf(d, fp) 767 struct bpf_d *d; 768 struct bpf_program *fp; 769 { 770 struct bpf_insn *fcode, *old; 771 u_int flen, size; 772 int s; 773 774 old = d->bd_filter; 775 if (fp->bf_insns == 0) { 776 if (fp->bf_len != 0) 777 return (EINVAL); 778 s = splimp(); 779 d->bd_filter = 0; 780 reset_d(d); 781 splx(s); 782 if (old != 0) 783 free((caddr_t)old, M_DEVBUF); 784 return (0); 785 } 786 flen = fp->bf_len; 787 if (flen > BPF_MAXINSNS) 788 return (EINVAL); 789 790 size = flen * sizeof(*fp->bf_insns); 791 fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK); 792 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 793 bpf_validate(fcode, (int)flen)) { 794 s = splimp(); 795 d->bd_filter = fcode; 796 reset_d(d); 797 splx(s); 798 if (old != 0) 799 free((caddr_t)old, M_DEVBUF); 800 801 return (0); 802 } 803 free((caddr_t)fcode, M_DEVBUF); 804 return (EINVAL); 805 } 806 807 /* 808 * Detach a file from its current interface (if attached at all) and attach 809 * to the interface indicated by the name stored in ifr. 810 * Return an errno or 0. 811 */ 812 static int 813 bpf_setif(d, ifr) 814 struct bpf_d *d; 815 struct ifreq *ifr; 816 { 817 struct bpf_if *bp; 818 char *cp; 819 int unit, s, error; 820 821 /* 822 * Separate string into name part and unit number. Put a null 823 * byte at the end of the name part, and compute the number. 824 * If the a unit number is unspecified, the default is 0, 825 * as initialized above. XXX This should be common code. 826 */ 827 unit = 0; 828 cp = ifr->ifr_name; 829 cp[sizeof(ifr->ifr_name) - 1] = '\0'; 830 while (*cp++) { 831 if (*cp >= '0' && *cp <= '9') { 832 unit = *cp - '0'; 833 *cp++ = '\0'; 834 while (*cp) 835 unit = 10 * unit + *cp++ - '0'; 836 break; 837 } 838 } 839 /* 840 * Look through attached interfaces for the named one. 841 */ 842 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 843 struct ifnet *ifp = bp->bif_ifp; 844 845 if (ifp == 0 || unit != ifp->if_unit 846 || strcmp(ifp->if_name, ifr->ifr_name) != 0) 847 continue; 848 /* 849 * We found the requested interface. 850 * If it's not up, return an error. 851 * Allocate the packet buffers if we need to. 852 * If we're already attached to requested interface, 853 * just flush the buffer. 854 */ 855 if ((ifp->if_flags & IFF_UP) == 0) 856 return (ENETDOWN); 857 858 if (d->bd_sbuf == 0) { 859 error = bpf_allocbufs(d); 860 if (error != 0) 861 return (error); 862 } 863 s = splimp(); 864 if (bp != d->bd_bif) { 865 if (d->bd_bif) 866 /* 867 * Detach if attached to something else. 868 */ 869 bpf_detachd(d); 870 871 bpf_attachd(d, bp); 872 } 873 reset_d(d); 874 splx(s); 875 return (0); 876 } 877 /* Not found. */ 878 return (ENXIO); 879 } 880 881 /* 882 * Convert an interface name plus unit number of an ifp to a single 883 * name which is returned in the ifr. 884 */ 885 static void 886 bpf_ifname(ifp, ifr) 887 struct ifnet *ifp; 888 struct ifreq *ifr; 889 { 890 char *s = ifp->if_name; 891 char *d = ifr->ifr_name; 892 893 while (*d++ = *s++) 894 continue; 895 /* XXX Assume that unit number is less than 10. */ 896 *d++ = ifp->if_unit + '0'; 897 *d = '\0'; 898 } 899 900 /* 901 * The new select interface passes down the proc pointer; the old select 902 * stubs had to grab it out of the user struct. This glue allows either case. 903 */ 904 #if BSD >= 199103 905 #define bpf_select bpfselect 906 #else 907 int 908 bpfselect(dev, rw) 909 register dev_t dev; 910 int rw; 911 { 912 return (bpf_select(dev, rw, u.u_procp)); 913 } 914 #endif 915 916 /* 917 * Support for select() system call 918 * Inspired by the code in tty.c for the same purpose. 919 * 920 * Return true iff the specific operation will not block indefinitely. 921 * Otherwise, return false but make a note that a selwakeup() must be done. 922 */ 923 int 924 bpf_select(dev, rw, p) 925 register dev_t dev; 926 int rw; 927 struct proc *p; 928 { 929 register struct bpf_d *d; 930 register int s; 931 932 if (rw != FREAD) 933 return (0); 934 /* 935 * An imitation of the FIONREAD ioctl code. 936 */ 937 d = &bpf_dtab[minor(dev)]; 938 939 s = splimp(); 940 if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) { 941 /* 942 * There is data waiting. 943 */ 944 splx(s); 945 return (1); 946 } 947 #if defined(__386BSD__) 948 selrecord(p, &d->bd_sel); 949 #else 950 /* 951 * No data ready. If there's already a select() waiting on this 952 * minor device then this is a collision. This shouldn't happen 953 * because minors really should not be shared, but if a process 954 * forks while one of these is open, it is possible that both 955 * processes could select on the same descriptor. 956 */ 957 if (d->bd_selproc && d->bd_selproc->p_wchan == (caddr_t)&selwait) 958 d->bd_selcoll = 1; 959 else 960 d->bd_selproc = p; 961 #endif 962 splx(s); 963 return (0); 964 } 965 966 /* 967 * Incoming linkage from device drivers. Process the packet pkt, of length 968 * pktlen, which is stored in a contiguous buffer. The packet is parsed 969 * by each process' filter, and if accepted, stashed into the corresponding 970 * buffer. 971 */ 972 void 973 bpf_tap(arg, pkt, pktlen) 974 caddr_t arg; 975 register u_char *pkt; 976 register u_int pktlen; 977 { 978 struct bpf_if *bp; 979 register struct bpf_d *d; 980 register u_int slen; 981 /* 982 * Note that the ipl does not have to be raised at this point. 983 * The only problem that could arise here is that if two different 984 * interfaces shared any data. This is not the case. 985 */ 986 bp = (struct bpf_if *)arg; 987 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 988 ++d->bd_rcount; 989 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); 990 if (slen != 0) 991 catchpacket(d, pkt, pktlen, slen, bcopy); 992 } 993 } 994 995 /* 996 * Copy data from an mbuf chain into a buffer. This code is derived 997 * from m_copydata in sys/uipc_mbuf.c. 998 */ 999 static void 1000 bpf_mcopy(src, dst, len) 1001 u_char *src; 1002 u_char *dst; 1003 register int len; 1004 { 1005 register struct mbuf *m = (struct mbuf *)src; 1006 register unsigned count; 1007 1008 while (len > 0) { 1009 if (m == 0) 1010 panic("bpf_mcopy"); 1011 count = MIN(m->m_len, len); 1012 bcopy(mtod(m, caddr_t), (caddr_t)dst, count); 1013 m = m->m_next; 1014 dst += count; 1015 len -= count; 1016 } 1017 } 1018 1019 /* 1020 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1021 */ 1022 void 1023 bpf_mtap(arg, m) 1024 caddr_t arg; 1025 struct mbuf *m; 1026 { 1027 struct bpf_if *bp = (struct bpf_if *)arg; 1028 struct bpf_d *d; 1029 u_int pktlen, slen; 1030 struct mbuf *m0; 1031 1032 pktlen = 0; 1033 for (m0 = m; m0 != 0; m0 = m0->m_next) 1034 pktlen += m0->m_len; 1035 1036 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1037 ++d->bd_rcount; 1038 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); 1039 if (slen != 0) 1040 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); 1041 } 1042 } 1043 1044 /* 1045 * Move the packet data from interface memory (pkt) into the 1046 * store buffer. Return 1 if it's time to wakeup a listener (buffer full), 1047 * otherwise 0. "copy" is the routine called to do the actual data 1048 * transfer. bcopy is passed in to copy contiguous chunks, while 1049 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1050 * pkt is really an mbuf. 1051 */ 1052 static void 1053 catchpacket(d, pkt, pktlen, snaplen, cpfn) 1054 register struct bpf_d *d; 1055 register u_char *pkt; 1056 register u_int pktlen, snaplen; 1057 register void (*cpfn)(); 1058 { 1059 register struct bpf_hdr *hp; 1060 register int totlen, curlen; 1061 register int hdrlen = d->bd_bif->bif_hdrlen; 1062 /* 1063 * Figure out how many bytes to move. If the packet is 1064 * greater or equal to the snapshot length, transfer that 1065 * much. Otherwise, transfer the whole packet (unless 1066 * we hit the buffer size limit). 1067 */ 1068 totlen = hdrlen + MIN(snaplen, pktlen); 1069 if (totlen > d->bd_bufsize) 1070 totlen = d->bd_bufsize; 1071 1072 /* 1073 * Round up the end of the previous packet to the next longword. 1074 */ 1075 curlen = BPF_WORDALIGN(d->bd_slen); 1076 if (curlen + totlen > d->bd_bufsize) { 1077 /* 1078 * This packet will overflow the storage buffer. 1079 * Rotate the buffers if we can, then wakeup any 1080 * pending reads. 1081 */ 1082 if (d->bd_fbuf == 0) { 1083 /* 1084 * We haven't completed the previous read yet, 1085 * so drop the packet. 1086 */ 1087 ++d->bd_dcount; 1088 return; 1089 } 1090 ROTATE_BUFFERS(d); 1091 bpf_wakeup(d); 1092 curlen = 0; 1093 } 1094 else if (d->bd_immediate) 1095 /* 1096 * Immediate mode is set. A packet arrived so any 1097 * reads should be woken up. 1098 */ 1099 bpf_wakeup(d); 1100 1101 /* 1102 * Append the bpf header. 1103 */ 1104 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1105 #if BSD >= 199103 1106 microtime(&hp->bh_tstamp); 1107 #elif defined(sun) 1108 uniqtime(&hp->bh_tstamp); 1109 #else 1110 hp->bh_tstamp = time; 1111 #endif 1112 hp->bh_datalen = pktlen; 1113 hp->bh_hdrlen = hdrlen; 1114 /* 1115 * Copy the packet data into the store buffer and update its length. 1116 */ 1117 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1118 d->bd_slen = curlen + totlen; 1119 } 1120 1121 /* 1122 * Initialize all nonzero fields of a descriptor. 1123 */ 1124 static int 1125 bpf_allocbufs(d) 1126 register struct bpf_d *d; 1127 { 1128 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1129 if (d->bd_fbuf == 0) 1130 return (ENOBUFS); 1131 1132 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1133 if (d->bd_sbuf == 0) { 1134 free(d->bd_fbuf, M_DEVBUF); 1135 return (ENOBUFS); 1136 } 1137 d->bd_slen = 0; 1138 d->bd_hlen = 0; 1139 return (0); 1140 } 1141 1142 /* 1143 * Free buffers currently in use by a descriptor. 1144 * Called on close. 1145 */ 1146 static void 1147 bpf_freed(d) 1148 register struct bpf_d *d; 1149 { 1150 /* 1151 * We don't need to lock out interrupts since this descriptor has 1152 * been detached from its interface and it yet hasn't been marked 1153 * free. 1154 */ 1155 if (d->bd_sbuf != 0) { 1156 free(d->bd_sbuf, M_DEVBUF); 1157 if (d->bd_hbuf != 0) 1158 free(d->bd_hbuf, M_DEVBUF); 1159 if (d->bd_fbuf != 0) 1160 free(d->bd_fbuf, M_DEVBUF); 1161 } 1162 if (d->bd_filter) 1163 free((caddr_t)d->bd_filter, M_DEVBUF); 1164 1165 D_MARKFREE(d); 1166 } 1167 1168 /* 1169 * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *) 1170 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed 1171 * size of the link header (variable length headers not yet supported). 1172 */ 1173 void 1174 bpfattach(driverp, ifp, dlt, hdrlen) 1175 caddr_t *driverp; 1176 struct ifnet *ifp; 1177 u_int dlt, hdrlen; 1178 { 1179 struct bpf_if *bp; 1180 int i; 1181 #if BSD < 199103 1182 static struct bpf_if bpf_ifs[NBPFILTER]; 1183 static int bpfifno; 1184 1185 bp = (bpfifno < NBPFILTER) ? &bpf_ifs[bpfifno++] : 0; 1186 #else 1187 bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1188 #endif 1189 if (bp == 0) 1190 panic("bpfattach"); 1191 1192 bp->bif_dlist = 0; 1193 bp->bif_driverp = (struct bpf_if **)driverp; 1194 bp->bif_ifp = ifp; 1195 bp->bif_dlt = dlt; 1196 1197 bp->bif_next = bpf_iflist; 1198 bpf_iflist = bp; 1199 1200 *bp->bif_driverp = 0; 1201 1202 /* 1203 * Compute the length of the bpf header. This is not necessarily 1204 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1205 * that the network layer header begins on a longword boundary (for 1206 * performance reasons and to alleviate alignment restrictions). 1207 */ 1208 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1209 1210 /* 1211 * Mark all the descriptors free if this hasn't been done. 1212 */ 1213 if (!D_ISFREE(&bpf_dtab[0])) 1214 for (i = 0; i < NBPFILTER; ++i) 1215 D_MARKFREE(&bpf_dtab[i]); 1216 1217 printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit); 1218 } 1219 1220 #if BSD >= 199103 1221 /* XXX This routine belongs in net/if.c. */ 1222 /* 1223 * Set/clear promiscuous mode on interface ifp based on the truth value 1224 * of pswitch. The calls are reference counted so that only the first 1225 * "on" request actually has an effect, as does the final "off" request. 1226 * Results are undefined if the "off" and "on" requests are not matched. 1227 */ 1228 int 1229 ifpromisc(ifp, pswitch) 1230 struct ifnet *ifp; 1231 int pswitch; 1232 { 1233 struct ifreq ifr; 1234 /* 1235 * If the device is not configured up, we cannot put it in 1236 * promiscuous mode. 1237 */ 1238 if ((ifp->if_flags & IFF_UP) == 0) 1239 return (ENETDOWN); 1240 1241 if (pswitch) { 1242 if (ifp->if_pcount++ != 0) 1243 return (0); 1244 ifp->if_flags |= IFF_PROMISC; 1245 } else { 1246 if (--ifp->if_pcount > 0) 1247 return (0); 1248 ifp->if_flags &= ~IFF_PROMISC; 1249 } 1250 ifr.ifr_flags = ifp->if_flags; 1251 return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr)); 1252 } 1253 #endif 1254 1255 #if BSD < 199103 1256 /* 1257 * Allocate some memory for bpf. This is temporary SunOS support, and 1258 * is admittedly a hack. 1259 * If resources unavaiable, return 0. 1260 */ 1261 static caddr_t 1262 bpf_alloc(size, canwait) 1263 register int size; 1264 register int canwait; 1265 { 1266 register struct mbuf *m; 1267 1268 if ((unsigned)size > (MCLBYTES-8)) 1269 return 0; 1270 1271 MGET(m, canwait, MT_DATA); 1272 if (m == 0) 1273 return 0; 1274 if ((unsigned)size > (MLEN-8)) { 1275 MCLGET(m); 1276 if (m->m_len != MCLBYTES) { 1277 m_freem(m); 1278 return 0; 1279 } 1280 } 1281 *mtod(m, struct mbuf **) = m; 1282 return mtod(m, caddr_t) + 8; 1283 } 1284 #endif 1285 #endif 1286