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 * @(#)bpf.c 7.5 (Berkeley) 7/15/91 39 * 40 * static char rcsid[] = 41 * "$Header: /cvsroot/src/sys/net/bpf.c,v 1.4 1993/04/09 11:02:51 glass Exp $"; 42 */ 43 44 #include "bpfilter.h" 45 46 #if NBPFILTER > 0 47 48 #ifndef __386BSD__ 49 #define __386BSD__ 50 #endif 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/mbuf.h> 55 #include <sys/buf.h> 56 #include <sys/dir.h> 57 #include <sys/time.h> 58 #include <sys/proc.h> 59 #include <sys/user.h> 60 #include <sys/ioctl.h> 61 62 #include <sys/file.h> 63 #if defined(sparc) && BSD < 199103 64 #include <sys/stream.h> 65 #endif 66 #include <sys/tty.h> 67 #include <sys/uio.h> 68 69 #include <sys/protosw.h> 70 #include <sys/socket.h> 71 #include <net/if.h> 72 73 #include <net/bpf.h> 74 #include <net/bpfdesc.h> 75 76 #include <sys/errno.h> 77 78 #include <netinet/in.h> 79 #include <netinet/if_ether.h> 80 #include <sys/kernel.h> 81 82 /* 83 * Older BSDs don't have kernel malloc. 84 */ 85 #if BSD < 199103 86 extern bcopy(); 87 static caddr_t bpf_alloc(); 88 #include <net/bpf_compat.h> 89 #define BPF_BUFSIZE (MCLBYTES-8) 90 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio) 91 #else 92 #define BPF_BUFSIZE 4096 93 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio) 94 #endif 95 96 #define PRINET 26 /* interruptible */ 97 98 /* 99 * The default read buffer size is patchable. 100 */ 101 int bpf_bufsize = BPF_BUFSIZE; 102 103 /* 104 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 105 * bpf_dtab holds the descriptors, indexed by minor device # 106 */ 107 struct bpf_if *bpf_iflist; 108 struct bpf_d bpf_dtab[NBPFILTER]; 109 110 static void bpf_ifname(); 111 static void catchpacket(); 112 static void bpf_freed(); 113 static int bpf_setif(); 114 static int bpf_initd(); 115 static int bpf_allocbufs(); 116 117 static int 118 bpf_movein(uio, linktype, mp, sockp) 119 register struct uio *uio; 120 int linktype; 121 register struct mbuf **mp; 122 register struct sockaddr *sockp; 123 { 124 struct mbuf *m; 125 int error; 126 int len; 127 int hlen; 128 129 /* 130 * Build a sockaddr based on the data link layer type. 131 * We do this at this level because the ethernet header 132 * is copied directly into the data field of the sockaddr. 133 * In the case of SLIP, there is no header and the packet 134 * is forwarded as is. 135 * Also, we are careful to leave room at the front of the mbuf 136 * for the link level header. 137 */ 138 switch (linktype) { 139 140 case DLT_SLIP: 141 sockp->sa_family = AF_INET; 142 hlen = 0; 143 break; 144 145 case DLT_EN10MB: 146 sockp->sa_family = AF_UNSPEC; 147 /* XXX Would MAXLINKHDR be better? */ 148 hlen = sizeof(struct ether_header); 149 break; 150 151 case DLT_FDDI: 152 sockp->sa_family = AF_UNSPEC; 153 /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */ 154 hlen = 24; 155 break; 156 157 case DLT_NULL: 158 sockp->sa_family = AF_UNSPEC; 159 hlen = 0; 160 break; 161 162 default: 163 return (EIO); 164 } 165 166 len = uio->uio_resid; 167 if ((unsigned)len > MCLBYTES) 168 return (EIO); 169 170 MGET(m, M_WAIT, MT_DATA); 171 if (m == 0) 172 return (ENOBUFS); 173 if (len > MLEN) { 174 #if BSD >= 199103 175 MCLGET(m, M_WAIT); 176 if ((m->m_flags & M_EXT) == 0) { 177 #else 178 MCLGET(m); 179 if (m->m_len != MCLBYTES) { 180 #endif 181 error = ENOBUFS; 182 goto bad; 183 } 184 } 185 m->m_len = len; 186 *mp = m; 187 /* 188 * Make room for link header. 189 */ 190 if (hlen != 0) { 191 m->m_len -= hlen; 192 #if BSD >= 199103 193 m->m_data += hlen; /* XXX */ 194 #else 195 m->m_off += hlen; 196 #endif 197 error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio); 198 if (error) 199 goto bad; 200 } 201 error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio); 202 if (!error) 203 return (0); 204 bad: 205 m_freem(m); 206 return (error); 207 } 208 209 /* 210 * Attach file to the bpf interface, i.e. make d listen on bp. 211 * Must be called at splimp. 212 */ 213 static void 214 bpf_attachd(d, bp) 215 struct bpf_d *d; 216 struct bpf_if *bp; 217 { 218 /* 219 * Point d at bp, and add d to the interface's list of listeners. 220 * Finally, point the driver's bpf cookie at the interface so 221 * it will divert packets to bpf. 222 */ 223 d->bd_bif = bp; 224 d->bd_next = bp->bif_dlist; 225 bp->bif_dlist = d; 226 227 *bp->bif_driverp = bp; 228 } 229 230 /* 231 * Detach a file from its interface. 232 */ 233 static void 234 bpf_detachd(d) 235 struct bpf_d *d; 236 { 237 struct bpf_d **p; 238 struct bpf_if *bp; 239 240 bp = d->bd_bif; 241 /* 242 * Check if this descriptor had requested promiscuous mode. 243 * If so, turn it off. 244 */ 245 if (d->bd_promisc) { 246 d->bd_promisc = 0; 247 if (ifpromisc(bp->bif_ifp, 0)) 248 /* 249 * Something is really wrong if we were able to put 250 * the driver into promiscuous mode, but can't 251 * take it out. 252 */ 253 panic("bpf: ifpromisc failed"); 254 } 255 /* Remove d from the interface's descriptor list. */ 256 p = &bp->bif_dlist; 257 while (*p != d) { 258 p = &(*p)->bd_next; 259 if (*p == 0) 260 panic("bpf_detachd: descriptor not in list"); 261 } 262 *p = (*p)->bd_next; 263 if (bp->bif_dlist == 0) 264 /* 265 * Let the driver know that there are no more listeners. 266 */ 267 *d->bd_bif->bif_driverp = 0; 268 d->bd_bif = 0; 269 } 270 271 272 /* 273 * Mark a descriptor free by making it point to itself. 274 * This is probably cheaper than marking with a constant since 275 * the address should be in a register anyway. 276 */ 277 #define D_ISFREE(d) ((d) == (d)->bd_next) 278 #define D_MARKFREE(d) ((d)->bd_next = (d)) 279 #define D_MARKUSED(d) ((d)->bd_next = 0) 280 281 /* 282 * Open ethernet device. Returns ENXIO for illegal minor device number, 283 * EBUSY if file is open by another process. 284 */ 285 /* ARGSUSED */ 286 int 287 bpfopen(dev, flag) 288 dev_t dev; 289 int flag; 290 { 291 register struct bpf_d *d; 292 293 if (minor(dev) >= NBPFILTER) 294 return (ENXIO); 295 /* 296 * Each minor can be opened by only one process. If the requested 297 * minor is in use, return EBUSY. 298 */ 299 d = &bpf_dtab[minor(dev)]; 300 if (!D_ISFREE(d)) 301 return (EBUSY); 302 303 /* Mark "free" and do most initialization. */ 304 bzero((char *)d, sizeof(*d)); 305 d->bd_bufsize = bpf_bufsize; 306 307 return (0); 308 } 309 310 /* 311 * Close the descriptor by detaching it from its interface, 312 * deallocating its buffers, and marking it free. 313 */ 314 /* ARGSUSED */ 315 int 316 bpfclose(dev, flag) 317 dev_t dev; 318 int flag; 319 { 320 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 321 register int s; 322 323 s = splimp(); 324 if (d->bd_bif) 325 bpf_detachd(d); 326 splx(s); 327 bpf_freed(d); 328 329 return (0); 330 } 331 332 /* 333 * Support for SunOS, which does not have tsleep. 334 */ 335 #if BSD < 199103 336 static 337 bpf_timeout(arg) 338 caddr_t arg; 339 { 340 struct bpf_d *d = (struct bpf_d *)arg; 341 d->bd_timedout = 1; 342 wakeup(arg); 343 } 344 345 #define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan) 346 347 int 348 bpf_sleep(d) 349 register struct bpf_d *d; 350 { 351 register int rto = d->bd_rtout; 352 register int st; 353 354 if (rto != 0) { 355 d->bd_timedout = 0; 356 timeout(bpf_timeout, (caddr_t)d, rto); 357 } 358 st = sleep((caddr_t)d, PRINET|PCATCH); 359 if (rto != 0) { 360 if (d->bd_timedout == 0) 361 untimeout(bpf_timeout, (caddr_t)d); 362 else if (st == 0) 363 return EWOULDBLOCK; 364 } 365 return (st != 0) ? EINTR : 0; 366 } 367 #else 368 #define BPF_SLEEP tsleep 369 #endif 370 371 /* 372 * Rotate the packet buffers in descriptor d. Move the store buffer 373 * into the hold slot, and the free buffer into the store slot. 374 * Zero the length of the new store buffer. 375 */ 376 #define ROTATE_BUFFERS(d) \ 377 (d)->bd_hbuf = (d)->bd_sbuf; \ 378 (d)->bd_hlen = (d)->bd_slen; \ 379 (d)->bd_sbuf = (d)->bd_fbuf; \ 380 (d)->bd_slen = 0; \ 381 (d)->bd_fbuf = 0; 382 /* 383 * bpfread - read next chunk of packets from buffers 384 */ 385 int 386 bpfread(dev, uio) 387 dev_t dev; 388 register struct uio *uio; 389 { 390 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 391 int error; 392 int s; 393 394 /* 395 * Restrict application to use a buffer the same size as 396 * as kernel buffers. 397 */ 398 if (uio->uio_resid != d->bd_bufsize) 399 return (EINVAL); 400 401 s = splimp(); 402 /* 403 * If the hold buffer is empty, then do a timed sleep, which 404 * ends when the timeout expires or when enough packets 405 * have arrived to fill the store buffer. 406 */ 407 while (d->bd_hbuf == 0) { 408 if (d->bd_immediate && d->bd_slen != 0) { 409 /* 410 * A packet(s) either arrived since the previous 411 * read or arrived while we were asleep. 412 * Rotate the buffers and return what's here. 413 */ 414 ROTATE_BUFFERS(d); 415 break; 416 } 417 error = BPF_SLEEP((caddr_t)d, PRINET|PCATCH, "bpf", 418 d->bd_rtout); 419 if (error == EINTR || error == ERESTART) { 420 splx(s); 421 return (error); 422 } 423 if (error == EWOULDBLOCK) { 424 /* 425 * On a timeout, return what's in the buffer, 426 * which may be nothing. If there is something 427 * in the store buffer, we can rotate the buffers. 428 */ 429 if (d->bd_hbuf) 430 /* 431 * We filled up the buffer in between 432 * getting the timeout and arriving 433 * here, so we don't need to rotate. 434 */ 435 break; 436 437 if (d->bd_slen == 0) { 438 splx(s); 439 return (0); 440 } 441 ROTATE_BUFFERS(d); 442 break; 443 } 444 } 445 /* 446 * At this point, we know we have something in the hold slot. 447 */ 448 splx(s); 449 450 /* 451 * Move data from hold buffer into user space. 452 * We know the entire buffer is transferred since 453 * we checked above that the read buffer is bpf_bufsize bytes. 454 */ 455 error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio); 456 457 s = splimp(); 458 d->bd_fbuf = d->bd_hbuf; 459 d->bd_hbuf = 0; 460 d->bd_hlen = 0; 461 splx(s); 462 463 return (error); 464 } 465 466 467 /* 468 * If there are processes sleeping on this descriptor, wake them up. 469 */ 470 static inline void 471 bpf_wakeup(d) 472 register struct bpf_d *d; 473 { 474 wakeup((caddr_t)d); 475 #if BSD > 199103 476 selwakeup(&d->bd_sel); 477 /* XXX */ 478 d->bd_sel.si_pid = 0; 479 #else 480 #if defined(__386BSD__) 481 if (d->bd_selpid) { 482 selwakeup(d->bd_selpid, (int)d->bd_selcoll); 483 d->bd_selcoll = 0; 484 d->bd_selpid = 0; /* XXX */ 485 } 486 #else 487 if (d->bd_selproc) { 488 selwakeup(d->bd_selproc, (int)d->bd_selcoll); 489 d->bd_selcoll = 0; 490 d->bd_selproc = 0; 491 } 492 #endif 493 #endif 494 } 495 496 int 497 bpfwrite(dev, uio) 498 dev_t dev; 499 struct uio *uio; 500 { 501 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 502 struct ifnet *ifp; 503 struct mbuf *m; 504 int error, s; 505 static struct sockaddr dst; 506 507 if (d->bd_bif == 0) 508 return (ENXIO); 509 510 ifp = d->bd_bif->bif_ifp; 511 512 if (uio->uio_resid == 0) 513 return (0); 514 if (uio->uio_resid > ifp->if_mtu) 515 return (EMSGSIZE); 516 517 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst); 518 if (error) 519 return (error); 520 521 s = splnet(); 522 #if BSD >= 199103 523 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0); 524 #else 525 error = (*ifp->if_output)(ifp, m, &dst); 526 #endif 527 splx(s); 528 /* 529 * The driver frees the mbuf. 530 */ 531 return (error); 532 } 533 534 /* 535 * Reset a descriptor by flushing its packet buffer and clearing the 536 * receive and drop counts. Should be called at splimp. 537 */ 538 static void 539 reset_d(d) 540 struct bpf_d *d; 541 { 542 if (d->bd_hbuf) { 543 /* Free the hold buffer. */ 544 d->bd_fbuf = d->bd_hbuf; 545 d->bd_hbuf = 0; 546 } 547 d->bd_slen = 0; 548 d->bd_hlen = 0; 549 d->bd_rcount = 0; 550 d->bd_dcount = 0; 551 } 552 553 /* 554 * FIONREAD Check for read packet available. 555 * SIOCGIFADDR Get interface address - convenient hook to driver. 556 * BIOCGBLEN Get buffer len [for read()]. 557 * BIOCSETF Set ethernet read filter. 558 * BIOCFLUSH Flush read packet buffer. 559 * BIOCPROMISC Put interface into promiscuous mode. 560 * BIOCGDLT Get link layer type. 561 * BIOCGETIF Get interface name. 562 * BIOCSETIF Set interface. 563 * BIOCSRTIMEOUT Set read timeout. 564 * BIOCGRTIMEOUT Get read timeout. 565 * BIOCGSTATS Get packet stats. 566 * BIOCIMMEDIATE Set immediate mode. 567 * BIOCVERSION Get filter language version. 568 */ 569 /* ARGSUSED */ 570 int 571 bpfioctl(dev, cmd, addr, flag) 572 dev_t dev; 573 int cmd; 574 caddr_t addr; 575 int flag; 576 { 577 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 578 int s, error = 0; 579 580 switch (cmd) { 581 582 default: 583 error = EINVAL; 584 break; 585 586 /* 587 * Check for read packet available. 588 */ 589 case FIONREAD: 590 { 591 int n; 592 593 s = splimp(); 594 n = d->bd_slen; 595 if (d->bd_hbuf) 596 n += d->bd_hlen; 597 splx(s); 598 599 *(int *)addr = n; 600 break; 601 } 602 603 case SIOCGIFADDR: 604 { 605 struct ifnet *ifp; 606 607 if (d->bd_bif == 0) 608 error = EINVAL; 609 else { 610 ifp = d->bd_bif->bif_ifp; 611 error = (*ifp->if_ioctl)(ifp, cmd, addr); 612 } 613 break; 614 } 615 616 /* 617 * Get buffer len [for read()]. 618 */ 619 case BIOCGBLEN: 620 *(u_int *)addr = d->bd_bufsize; 621 break; 622 623 /* 624 * Set buffer length. 625 */ 626 case BIOCSBLEN: 627 #if BSD < 199103 628 error = EINVAL; 629 #else 630 if (d->bd_bif != 0) 631 error = EINVAL; 632 else { 633 register u_int size = *(u_int *)addr; 634 635 if (size > BPF_MAXBUFSIZE) 636 *(u_int *)addr = size = BPF_MAXBUFSIZE; 637 else if (size < BPF_MINBUFSIZE) 638 *(u_int *)addr = size = BPF_MINBUFSIZE; 639 d->bd_bufsize = size; 640 } 641 #endif 642 break; 643 644 /* 645 * Set link layer read filter. 646 */ 647 case BIOCSETF: 648 error = bpf_setf(d, (struct bpf_program *)addr); 649 break; 650 651 /* 652 * Flush read packet buffer. 653 */ 654 case BIOCFLUSH: 655 s = splimp(); 656 reset_d(d); 657 splx(s); 658 break; 659 660 /* 661 * Put interface into promiscuous mode. 662 */ 663 case BIOCPROMISC: 664 if (d->bd_bif == 0) { 665 /* 666 * No interface attached yet. 667 */ 668 error = EINVAL; 669 break; 670 } 671 s = splimp(); 672 if (d->bd_promisc == 0) { 673 error = ifpromisc(d->bd_bif->bif_ifp, 1); 674 if (error == 0) 675 d->bd_promisc = 1; 676 } 677 splx(s); 678 break; 679 680 /* 681 * Get device parameters. 682 */ 683 case BIOCGDLT: 684 if (d->bd_bif == 0) 685 error = EINVAL; 686 else 687 *(u_int *)addr = d->bd_bif->bif_dlt; 688 break; 689 690 /* 691 * Set interface name. 692 */ 693 case BIOCGETIF: 694 if (d->bd_bif == 0) 695 error = EINVAL; 696 else 697 bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr); 698 break; 699 700 /* 701 * Set interface. 702 */ 703 case BIOCSETIF: 704 error = bpf_setif(d, (struct ifreq *)addr); 705 break; 706 707 /* 708 * Set read timeout. 709 */ 710 case BIOCSRTIMEOUT: 711 { 712 struct timeval *tv = (struct timeval *)addr; 713 u_long msec; 714 715 /* Compute number of milliseconds. */ 716 msec = tv->tv_sec * 1000 + tv->tv_usec / 1000; 717 /* Scale milliseconds to ticks. Assume hard 718 clock has millisecond or greater resolution 719 (i.e. tick >= 1000). For 10ms hardclock, 720 tick/1000 = 10, so rtout<-msec/10. */ 721 d->bd_rtout = msec / (tick / 1000); 722 break; 723 } 724 725 /* 726 * Get read timeout. 727 */ 728 case BIOCGRTIMEOUT: 729 { 730 struct timeval *tv = (struct timeval *)addr; 731 u_long msec = d->bd_rtout; 732 733 msec *= tick / 1000; 734 tv->tv_sec = msec / 1000; 735 tv->tv_usec = msec % 1000; 736 break; 737 } 738 739 /* 740 * Get packet stats. 741 */ 742 case BIOCGSTATS: 743 { 744 struct bpf_stat *bs = (struct bpf_stat *)addr; 745 746 bs->bs_recv = d->bd_rcount; 747 bs->bs_drop = d->bd_dcount; 748 break; 749 } 750 751 /* 752 * Set immediate mode. 753 */ 754 case BIOCIMMEDIATE: 755 d->bd_immediate = *(u_int *)addr; 756 break; 757 758 case BIOCVERSION: 759 { 760 struct bpf_version *bv = (struct bpf_version *)addr; 761 762 bv->bv_major = BPF_MAJOR_VERSION; 763 bv->bv_minor = BPF_MINOR_VERSION; 764 break; 765 } 766 } 767 return (error); 768 } 769 770 /* 771 * Set d's packet filter program to fp. If this file already has a filter, 772 * free it and replace it. Returns EINVAL for bogus requests. 773 */ 774 int 775 bpf_setf(d, fp) 776 struct bpf_d *d; 777 struct bpf_program *fp; 778 { 779 struct bpf_insn *fcode, *old; 780 u_int flen, size; 781 int s; 782 783 old = d->bd_filter; 784 if (fp->bf_insns == 0) { 785 if (fp->bf_len != 0) 786 return (EINVAL); 787 s = splimp(); 788 d->bd_filter = 0; 789 reset_d(d); 790 splx(s); 791 if (old != 0) 792 free((caddr_t)old, M_DEVBUF); 793 return (0); 794 } 795 flen = fp->bf_len; 796 if (flen > BPF_MAXINSNS) 797 return (EINVAL); 798 799 size = flen * sizeof(*fp->bf_insns); 800 fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK); 801 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 802 bpf_validate(fcode, (int)flen)) { 803 s = splimp(); 804 d->bd_filter = fcode; 805 reset_d(d); 806 splx(s); 807 if (old != 0) 808 free((caddr_t)old, M_DEVBUF); 809 810 return (0); 811 } 812 free((caddr_t)fcode, M_DEVBUF); 813 return (EINVAL); 814 } 815 816 /* 817 * Detach a file from its current interface (if attached at all) and attach 818 * to the interface indicated by the name stored in ifr. 819 * Return an errno or 0. 820 */ 821 static int 822 bpf_setif(d, ifr) 823 struct bpf_d *d; 824 struct ifreq *ifr; 825 { 826 struct bpf_if *bp; 827 char *cp; 828 int unit, s, error; 829 830 /* 831 * Separate string into name part and unit number. Put a null 832 * byte at the end of the name part, and compute the number. 833 * If the a unit number is unspecified, the default is 0, 834 * as initialized above. XXX This should be common code. 835 */ 836 unit = 0; 837 cp = ifr->ifr_name; 838 cp[sizeof(ifr->ifr_name) - 1] = '\0'; 839 while (*cp++) { 840 if (*cp >= '0' && *cp <= '9') { 841 unit = *cp - '0'; 842 *cp++ = '\0'; 843 while (*cp) 844 unit = 10 * unit + *cp++ - '0'; 845 break; 846 } 847 } 848 /* 849 * Look through attached interfaces for the named one. 850 */ 851 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 852 struct ifnet *ifp = bp->bif_ifp; 853 854 if (ifp == 0 || unit != ifp->if_unit 855 || strcmp(ifp->if_name, ifr->ifr_name) != 0) 856 continue; 857 /* 858 * We found the requested interface. 859 * If it's not up, return an error. 860 * Allocate the packet buffers if we need to. 861 * If we're already attached to requested interface, 862 * just flush the buffer. 863 */ 864 if ((ifp->if_flags & IFF_UP) == 0) 865 return (ENETDOWN); 866 867 if (d->bd_sbuf == 0) { 868 error = bpf_allocbufs(d); 869 if (error != 0) 870 return (error); 871 } 872 s = splimp(); 873 if (bp != d->bd_bif) { 874 if (d->bd_bif) 875 /* 876 * Detach if attached to something else. 877 */ 878 bpf_detachd(d); 879 880 bpf_attachd(d, bp); 881 } 882 reset_d(d); 883 splx(s); 884 return (0); 885 } 886 /* Not found. */ 887 return (ENXIO); 888 } 889 890 /* 891 * Convert an interface name plus unit number of an ifp to a single 892 * name which is returned in the ifr. 893 */ 894 static void 895 bpf_ifname(ifp, ifr) 896 struct ifnet *ifp; 897 struct ifreq *ifr; 898 { 899 char *s = ifp->if_name; 900 char *d = ifr->ifr_name; 901 902 while (*d++ = *s++) 903 continue; 904 /* XXX Assume that unit number is less than 10. */ 905 *d++ = ifp->if_unit + '0'; 906 *d = '\0'; 907 } 908 909 /* 910 * The new select interface passes down the proc pointer; the old select 911 * stubs had to grab it out of the user struct. This glue allows either case. 912 */ 913 #if BSD >= 199103 914 #define bpf_select bpfselect 915 #else 916 int 917 bpfselect(dev, rw) 918 register dev_t dev; 919 int rw; 920 { 921 return (bpf_select(dev, rw, u.u_procp)); 922 } 923 #endif 924 925 /* 926 * Support for select() system call 927 * Inspired by the code in tty.c for the same purpose. 928 * 929 * Return true iff the specific operation will not block indefinitely. 930 * Otherwise, return false but make a note that a selwakeup() must be done. 931 */ 932 int 933 bpf_select(dev, rw, p) 934 register dev_t dev; 935 int rw; 936 struct proc *p; 937 { 938 register struct bpf_d *d; 939 register int s; 940 #if defined(__386BSD__) 941 struct proc *p2; 942 #endif 943 944 if (rw != FREAD) 945 return (0); 946 /* 947 * An imitation of the FIONREAD ioctl code. 948 */ 949 d = &bpf_dtab[minor(dev)]; 950 951 s = splimp(); 952 if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) { 953 /* 954 * There is data waiting. 955 */ 956 splx(s); 957 return (1); 958 } 959 #if 0 960 selrecord(p, &d->bd_sel); 961 #else 962 /* 963 * No data ready. If there's already a select() waiting on this 964 * minor device then this is a collision. This shouldn't happen 965 * because minors really should not be shared, but if a process 966 * forks while one of these is open, it is possible that both 967 * processes could select on the same descriptor. 968 */ 969 #if defined(__386BSD__) 970 if (d->bd_selpid && (p2=pfind(d->bd_selpid)) && p2->p_wchan == (caddr_t)&selwait) 971 d->bd_selcoll = 1; 972 else 973 d->bd_selpid = p->p_pid; 974 #else 975 if (d->bd_selproc && d->bd_selproc->p_wchan == (caddr_t)&selwait) 976 d->bd_selcoll = 1; 977 else 978 d->bd_selproc = p; 979 #endif 980 #endif 981 splx(s); 982 return (0); 983 } 984 985 /* 986 * Incoming linkage from device drivers. Process the packet pkt, of length 987 * pktlen, which is stored in a contiguous buffer. The packet is parsed 988 * by each process' filter, and if accepted, stashed into the corresponding 989 * buffer. 990 */ 991 void 992 bpf_tap(arg, pkt, pktlen) 993 caddr_t arg; 994 register u_char *pkt; 995 register u_int pktlen; 996 { 997 struct bpf_if *bp; 998 register struct bpf_d *d; 999 register u_int slen; 1000 /* 1001 * Note that the ipl does not have to be raised at this point. 1002 * The only problem that could arise here is that if two different 1003 * interfaces shared any data. This is not the case. 1004 */ 1005 bp = (struct bpf_if *)arg; 1006 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1007 ++d->bd_rcount; 1008 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); 1009 if (slen != 0) 1010 catchpacket(d, pkt, pktlen, slen, bcopy); 1011 } 1012 } 1013 1014 /* 1015 * Copy data from an mbuf chain into a buffer. This code is derived 1016 * from m_copydata in sys/uipc_mbuf.c. 1017 */ 1018 static void 1019 bpf_mcopy(src, dst, len) 1020 u_char *src; 1021 u_char *dst; 1022 register int len; 1023 { 1024 register struct mbuf *m = (struct mbuf *)src; 1025 register unsigned count; 1026 1027 while (len > 0) { 1028 if (m == 0) 1029 panic("bpf_mcopy"); 1030 count = MIN(m->m_len, len); 1031 bcopy(mtod(m, caddr_t), (caddr_t)dst, count); 1032 m = m->m_next; 1033 dst += count; 1034 len -= count; 1035 } 1036 } 1037 1038 /* 1039 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1040 */ 1041 void 1042 bpf_mtap(arg, m) 1043 caddr_t arg; 1044 struct mbuf *m; 1045 { 1046 struct bpf_if *bp = (struct bpf_if *)arg; 1047 struct bpf_d *d; 1048 u_int pktlen, slen; 1049 struct mbuf *m0; 1050 1051 pktlen = 0; 1052 for (m0 = m; m0 != 0; m0 = m0->m_next) 1053 pktlen += m0->m_len; 1054 1055 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1056 ++d->bd_rcount; 1057 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); 1058 if (slen != 0) 1059 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); 1060 } 1061 } 1062 1063 /* 1064 * Move the packet data from interface memory (pkt) into the 1065 * store buffer. Return 1 if it's time to wakeup a listener (buffer full), 1066 * otherwise 0. "copy" is the routine called to do the actual data 1067 * transfer. bcopy is passed in to copy contiguous chunks, while 1068 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1069 * pkt is really an mbuf. 1070 */ 1071 static void 1072 catchpacket(d, pkt, pktlen, snaplen, cpfn) 1073 register struct bpf_d *d; 1074 register u_char *pkt; 1075 register u_int pktlen, snaplen; 1076 register void (*cpfn)(); 1077 { 1078 register struct bpf_hdr *hp; 1079 register int totlen, curlen; 1080 register int hdrlen = d->bd_bif->bif_hdrlen; 1081 /* 1082 * Figure out how many bytes to move. If the packet is 1083 * greater or equal to the snapshot length, transfer that 1084 * much. Otherwise, transfer the whole packet (unless 1085 * we hit the buffer size limit). 1086 */ 1087 totlen = hdrlen + MIN(snaplen, pktlen); 1088 if (totlen > d->bd_bufsize) 1089 totlen = d->bd_bufsize; 1090 1091 /* 1092 * Round up the end of the previous packet to the next longword. 1093 */ 1094 curlen = BPF_WORDALIGN(d->bd_slen); 1095 if (curlen + totlen > d->bd_bufsize) { 1096 /* 1097 * This packet will overflow the storage buffer. 1098 * Rotate the buffers if we can, then wakeup any 1099 * pending reads. 1100 */ 1101 if (d->bd_fbuf == 0) { 1102 /* 1103 * We haven't completed the previous read yet, 1104 * so drop the packet. 1105 */ 1106 ++d->bd_dcount; 1107 return; 1108 } 1109 ROTATE_BUFFERS(d); 1110 bpf_wakeup(d); 1111 curlen = 0; 1112 } 1113 else if (d->bd_immediate) 1114 /* 1115 * Immediate mode is set. A packet arrived so any 1116 * reads should be woken up. 1117 */ 1118 bpf_wakeup(d); 1119 1120 /* 1121 * Append the bpf header. 1122 */ 1123 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1124 #if BSD >= 199103 1125 microtime(&hp->bh_tstamp); 1126 #elif defined(sun) 1127 uniqtime(&hp->bh_tstamp); 1128 #else 1129 hp->bh_tstamp = time; 1130 #endif 1131 hp->bh_datalen = pktlen; 1132 hp->bh_hdrlen = hdrlen; 1133 /* 1134 * Copy the packet data into the store buffer and update its length. 1135 */ 1136 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1137 d->bd_slen = curlen + totlen; 1138 } 1139 1140 /* 1141 * Initialize all nonzero fields of a descriptor. 1142 */ 1143 static int 1144 bpf_allocbufs(d) 1145 register struct bpf_d *d; 1146 { 1147 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1148 if (d->bd_fbuf == 0) 1149 return (ENOBUFS); 1150 1151 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1152 if (d->bd_sbuf == 0) { 1153 free(d->bd_fbuf, M_DEVBUF); 1154 return (ENOBUFS); 1155 } 1156 d->bd_slen = 0; 1157 d->bd_hlen = 0; 1158 return (0); 1159 } 1160 1161 /* 1162 * Free buffers currently in use by a descriptor. 1163 * Called on close. 1164 */ 1165 static void 1166 bpf_freed(d) 1167 register struct bpf_d *d; 1168 { 1169 /* 1170 * We don't need to lock out interrupts since this descriptor has 1171 * been detached from its interface and it yet hasn't been marked 1172 * free. 1173 */ 1174 if (d->bd_sbuf != 0) { 1175 free(d->bd_sbuf, M_DEVBUF); 1176 if (d->bd_hbuf != 0) 1177 free(d->bd_hbuf, M_DEVBUF); 1178 if (d->bd_fbuf != 0) 1179 free(d->bd_fbuf, M_DEVBUF); 1180 } 1181 if (d->bd_filter) 1182 free((caddr_t)d->bd_filter, M_DEVBUF); 1183 1184 D_MARKFREE(d); 1185 } 1186 1187 /* 1188 * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *) 1189 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed 1190 * size of the link header (variable length headers not yet supported). 1191 */ 1192 void 1193 bpfattach(driverp, ifp, dlt, hdrlen) 1194 caddr_t *driverp; 1195 struct ifnet *ifp; 1196 u_int dlt, hdrlen; 1197 { 1198 struct bpf_if *bp; 1199 int i; 1200 #if BSD < 199103 1201 static struct bpf_if bpf_ifs[NBPFILTER]; 1202 static int bpfifno; 1203 1204 bp = (bpfifno < NBPFILTER) ? &bpf_ifs[bpfifno++] : 0; 1205 #else 1206 bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1207 #endif 1208 if (bp == 0) 1209 panic("bpfattach"); 1210 1211 bp->bif_dlist = 0; 1212 bp->bif_driverp = (struct bpf_if **)driverp; 1213 bp->bif_ifp = ifp; 1214 bp->bif_dlt = dlt; 1215 1216 bp->bif_next = bpf_iflist; 1217 bpf_iflist = bp; 1218 1219 *bp->bif_driverp = 0; 1220 1221 /* 1222 * Compute the length of the bpf header. This is not necessarily 1223 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1224 * that the network layer header begins on a longword boundary (for 1225 * performance reasons and to alleviate alignment restrictions). 1226 */ 1227 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1228 1229 /* 1230 * Mark all the descriptors free if this hasn't been done. 1231 */ 1232 if (!D_ISFREE(&bpf_dtab[0])) 1233 for (i = 0; i < NBPFILTER; ++i) 1234 D_MARKFREE(&bpf_dtab[i]); 1235 1236 printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit); 1237 } 1238 1239 #if BSD >= 199103 1240 /* XXX This routine belongs in net/if.c. */ 1241 /* 1242 * Set/clear promiscuous mode on interface ifp based on the truth value 1243 * of pswitch. The calls are reference counted so that only the first 1244 * "on" request actually has an effect, as does the final "off" request. 1245 * Results are undefined if the "off" and "on" requests are not matched. 1246 */ 1247 int 1248 ifpromisc(ifp, pswitch) 1249 struct ifnet *ifp; 1250 int pswitch; 1251 { 1252 struct ifreq ifr; 1253 /* 1254 * If the device is not configured up, we cannot put it in 1255 * promiscuous mode. 1256 */ 1257 if ((ifp->if_flags & IFF_UP) == 0) 1258 return (ENETDOWN); 1259 1260 if (pswitch) { 1261 if (ifp->if_pcount++ != 0) 1262 return (0); 1263 ifp->if_flags |= IFF_PROMISC; 1264 } else { 1265 if (--ifp->if_pcount > 0) 1266 return (0); 1267 ifp->if_flags &= ~IFF_PROMISC; 1268 } 1269 ifr.ifr_flags = ifp->if_flags; 1270 return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr)); 1271 } 1272 #endif 1273 1274 #if BSD < 199103 1275 /* 1276 * Allocate some memory for bpf. This is temporary SunOS support, and 1277 * is admittedly a hack. 1278 * If resources unavaiable, return 0. 1279 */ 1280 static caddr_t 1281 bpf_alloc(size, canwait) 1282 register int size; 1283 register int canwait; 1284 { 1285 register struct mbuf *m; 1286 1287 if ((unsigned)size > (MCLBYTES-8)) 1288 return 0; 1289 1290 MGET(m, canwait, MT_DATA); 1291 if (m == 0) 1292 return 0; 1293 if ((unsigned)size > (MLEN-8)) { 1294 MCLGET(m); 1295 if (m->m_len != MCLBYTES) { 1296 m_freem(m); 1297 return 0; 1298 } 1299 } 1300 *mtod(m, struct mbuf **) = m; 1301 return mtod(m, caddr_t) + 8; 1302 } 1303 #endif 1304 #endif 1305