1 /* 2 * Copyright (c) 1990, 1991 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 * %sccs.include.redist.c% 11 * 12 * @(#)bpf.c 7.14 (Berkeley) 04/17/93 13 * 14 * static char rcsid[] = 15 * "$Header: bpf.c,v 1.33 91/10/27 21:21:58 mccanne Exp $"; 16 */ 17 18 #include "bpfilter.h" 19 20 #if NBPFILTER > 0 21 22 #ifndef __GNUC__ 23 #define inline 24 #else 25 #define inline __inline 26 #endif 27 28 #include <sys/param.h> 29 #include <sys/systm.h> 30 #include <sys/mbuf.h> 31 #include <sys/buf.h> 32 #include <sys/time.h> 33 #include <sys/proc.h> 34 #include <sys/user.h> 35 #include <sys/ioctl.h> 36 #include <sys/map.h> 37 38 #include <sys/file.h> 39 #if defined(sparc) && BSD < 199103 40 #include <sys/stream.h> 41 #endif 42 #include <sys/tty.h> 43 #include <sys/uio.h> 44 45 #include <sys/protosw.h> 46 #include <sys/socket.h> 47 #include <net/if.h> 48 49 #include <net/bpf.h> 50 #include <net/bpfdesc.h> 51 52 #include <sys/errno.h> 53 54 #include <netinet/in.h> 55 #include <netinet/if_ether.h> 56 #include <sys/kernel.h> 57 58 /* 59 * Older BSDs don't have kernel malloc. 60 */ 61 #if BSD < 199103 62 extern bcopy(); 63 static caddr_t bpf_alloc(); 64 #include <net/bpf_compat.h> 65 #define BPF_BUFSIZE (MCLBYTES-8) 66 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio) 67 #else 68 #define BPF_BUFSIZE 4096 69 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio) 70 #endif 71 72 #define PRINET 26 /* interruptible */ 73 74 /* 75 * The default read buffer size is patchable. 76 */ 77 int bpf_bufsize = BPF_BUFSIZE; 78 79 /* 80 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 81 * bpf_dtab holds the descriptors, indexed by minor device # 82 */ 83 struct bpf_if *bpf_iflist; 84 struct bpf_d bpf_dtab[NBPFILTER]; 85 86 #if BSD >= 199207 87 /* 88 * bpfilterattach() is called at boot time in new systems. We do 89 * nothing here since old systems will not call this. 90 */ 91 /* ARGSUSED */ 92 void 93 bpfilterattach(n) 94 int n; 95 { 96 } 97 #endif 98 99 static void bpf_ifname(); 100 static void catchpacket(); 101 static void bpf_freed(); 102 static int bpf_setif(); 103 static int bpf_initd(); 104 static int bpf_allocbufs(); 105 106 static int 107 bpf_movein(uio, linktype, mp, sockp, datlen) 108 register struct uio *uio; 109 int linktype, *datlen; 110 register struct mbuf **mp; 111 register struct sockaddr *sockp; 112 { 113 struct mbuf *m; 114 int error; 115 int len; 116 int hlen; 117 118 /* 119 * Build a sockaddr based on the data link layer type. 120 * We do this at this level because the ethernet header 121 * is copied directly into the data field of the sockaddr. 122 * In the case of SLIP, there is no header and the packet 123 * is forwarded as is. 124 * Also, we are careful to leave room at the front of the mbuf 125 * for the link level header. 126 */ 127 switch (linktype) { 128 129 case DLT_SLIP: 130 sockp->sa_family = AF_INET; 131 hlen = 0; 132 break; 133 134 case DLT_EN10MB: 135 sockp->sa_family = AF_UNSPEC; 136 /* XXX Would MAXLINKHDR be better? */ 137 hlen = sizeof(struct ether_header); 138 break; 139 140 case DLT_FDDI: 141 sockp->sa_family = AF_UNSPEC; 142 /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */ 143 hlen = 24; 144 break; 145 146 case DLT_NULL: 147 sockp->sa_family = AF_UNSPEC; 148 hlen = 0; 149 break; 150 151 default: 152 return (EIO); 153 } 154 155 len = uio->uio_resid; 156 *datlen = len - hlen; 157 if ((unsigned)len > MCLBYTES) 158 return (EIO); 159 160 MGET(m, M_WAIT, MT_DATA); 161 if (m == 0) 162 return (ENOBUFS); 163 if (len > MLEN) { 164 #if BSD >= 199103 165 MCLGET(m, M_WAIT); 166 if ((m->m_flags & M_EXT) == 0) { 167 #else 168 MCLGET(m); 169 if (m->m_len != MCLBYTES) { 170 #endif 171 error = ENOBUFS; 172 goto bad; 173 } 174 } 175 m->m_len = len; 176 *mp = m; 177 /* 178 * Make room for link header. 179 */ 180 if (hlen != 0) { 181 m->m_len -= hlen; 182 #if BSD >= 199103 183 m->m_data += hlen; /* XXX */ 184 #else 185 m->m_off += hlen; 186 #endif 187 error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio); 188 if (error) 189 goto bad; 190 } 191 error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio); 192 if (!error) 193 return (0); 194 bad: 195 m_freem(m); 196 return (error); 197 } 198 199 /* 200 * Attach file to the bpf interface, i.e. make d listen on bp. 201 * Must be called at splimp. 202 */ 203 static void 204 bpf_attachd(d, bp) 205 struct bpf_d *d; 206 struct bpf_if *bp; 207 { 208 /* 209 * Point d at bp, and add d to the interface's list of listeners. 210 * Finally, point the driver's bpf cookie at the interface so 211 * it will divert packets to bpf. 212 */ 213 d->bd_bif = bp; 214 d->bd_next = bp->bif_dlist; 215 bp->bif_dlist = d; 216 217 *bp->bif_driverp = bp; 218 } 219 220 /* 221 * Detach a file from its interface. 222 */ 223 static void 224 bpf_detachd(d) 225 struct bpf_d *d; 226 { 227 struct bpf_d **p; 228 struct bpf_if *bp; 229 230 bp = d->bd_bif; 231 /* 232 * Check if this descriptor had requested promiscuous mode. 233 * If so, turn it off. 234 */ 235 if (d->bd_promisc) { 236 d->bd_promisc = 0; 237 if (ifpromisc(bp->bif_ifp, 0)) 238 /* 239 * Something is really wrong if we were able to put 240 * the driver into promiscuous mode, but can't 241 * take it out. 242 */ 243 panic("bpf: ifpromisc failed"); 244 } 245 /* Remove d from the interface's descriptor list. */ 246 p = &bp->bif_dlist; 247 while (*p != d) { 248 p = &(*p)->bd_next; 249 if (*p == 0) 250 panic("bpf_detachd: descriptor not in list"); 251 } 252 *p = (*p)->bd_next; 253 if (bp->bif_dlist == 0) 254 /* 255 * Let the driver know that there are no more listeners. 256 */ 257 *d->bd_bif->bif_driverp = 0; 258 d->bd_bif = 0; 259 } 260 261 262 /* 263 * Mark a descriptor free by making it point to itself. 264 * This is probably cheaper than marking with a constant since 265 * the address should be in a register anyway. 266 */ 267 #define D_ISFREE(d) ((d) == (d)->bd_next) 268 #define D_MARKFREE(d) ((d)->bd_next = (d)) 269 #define D_MARKUSED(d) ((d)->bd_next = 0) 270 271 /* 272 * Open ethernet device. Returns ENXIO for illegal minor device number, 273 * EBUSY if file is open by another process. 274 */ 275 /* ARGSUSED */ 276 int 277 bpfopen(dev, flag) 278 dev_t dev; 279 int flag; 280 { 281 register struct bpf_d *d; 282 283 if (minor(dev) >= NBPFILTER) 284 return (ENXIO); 285 /* 286 * Each minor can be opened by only one process. If the requested 287 * minor is in use, return EBUSY. 288 */ 289 d = &bpf_dtab[minor(dev)]; 290 if (!D_ISFREE(d)) 291 return (EBUSY); 292 293 /* Mark "free" and do most initialization. */ 294 bzero((char *)d, sizeof(*d)); 295 d->bd_bufsize = bpf_bufsize; 296 297 return (0); 298 } 299 300 /* 301 * Close the descriptor by detaching it from its interface, 302 * deallocating its buffers, and marking it free. 303 */ 304 /* ARGSUSED */ 305 int 306 bpfclose(dev, flag) 307 dev_t dev; 308 int flag; 309 { 310 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 311 register int s; 312 313 s = splimp(); 314 if (d->bd_bif) 315 bpf_detachd(d); 316 splx(s); 317 bpf_freed(d); 318 319 return (0); 320 } 321 322 /* 323 * Support for SunOS, which does not have tsleep. 324 */ 325 #if BSD < 199103 326 static 327 bpf_timeout(arg) 328 caddr_t arg; 329 { 330 struct bpf_d *d = (struct bpf_d *)arg; 331 d->bd_timedout = 1; 332 wakeup(arg); 333 } 334 335 #define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan) 336 337 int 338 bpf_sleep(d) 339 register struct bpf_d *d; 340 { 341 register int rto = d->bd_rtout; 342 register int st; 343 344 if (rto != 0) { 345 d->bd_timedout = 0; 346 timeout(bpf_timeout, (caddr_t)d, rto); 347 } 348 st = sleep((caddr_t)d, PRINET|PCATCH); 349 if (rto != 0) { 350 if (d->bd_timedout == 0) 351 untimeout(bpf_timeout, (caddr_t)d); 352 else if (st == 0) 353 return EWOULDBLOCK; 354 } 355 return (st != 0) ? EINTR : 0; 356 } 357 #else 358 #define BPF_SLEEP tsleep 359 #endif 360 361 /* 362 * Rotate the packet buffers in descriptor d. Move the store buffer 363 * into the hold slot, and the free buffer into the store slot. 364 * Zero the length of the new store buffer. 365 */ 366 #define ROTATE_BUFFERS(d) \ 367 (d)->bd_hbuf = (d)->bd_sbuf; \ 368 (d)->bd_hlen = (d)->bd_slen; \ 369 (d)->bd_sbuf = (d)->bd_fbuf; \ 370 (d)->bd_slen = 0; \ 371 (d)->bd_fbuf = 0; 372 /* 373 * bpfread - read next chunk of packets from buffers 374 */ 375 int 376 bpfread(dev, uio) 377 dev_t dev; 378 register struct uio *uio; 379 { 380 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 381 int error; 382 int s; 383 384 /* 385 * Restrict application to use a buffer the same size as 386 * as kernel buffers. 387 */ 388 if (uio->uio_resid != d->bd_bufsize) 389 return (EINVAL); 390 391 s = splimp(); 392 /* 393 * If the hold buffer is empty, then do a timed sleep, which 394 * ends when the timeout expires or when enough packets 395 * have arrived to fill the store buffer. 396 */ 397 while (d->bd_hbuf == 0) { 398 if (d->bd_immediate && d->bd_slen != 0) { 399 /* 400 * A packet(s) either arrived since the previous 401 * read or arrived while we were asleep. 402 * Rotate the buffers and return what's here. 403 */ 404 ROTATE_BUFFERS(d); 405 break; 406 } 407 error = BPF_SLEEP((caddr_t)d, PRINET|PCATCH, "bpf", 408 d->bd_rtout); 409 if (error == EINTR || error == ERESTART) { 410 splx(s); 411 return (error); 412 } 413 if (error == EWOULDBLOCK) { 414 /* 415 * On a timeout, return what's in the buffer, 416 * which may be nothing. If there is something 417 * in the store buffer, we can rotate the buffers. 418 */ 419 if (d->bd_hbuf) 420 /* 421 * We filled up the buffer in between 422 * getting the timeout and arriving 423 * here, so we don't need to rotate. 424 */ 425 break; 426 427 if (d->bd_slen == 0) { 428 splx(s); 429 return (0); 430 } 431 ROTATE_BUFFERS(d); 432 break; 433 } 434 } 435 /* 436 * At this point, we know we have something in the hold slot. 437 */ 438 splx(s); 439 440 /* 441 * Move data from hold buffer into user space. 442 * We know the entire buffer is transferred since 443 * we checked above that the read buffer is bpf_bufsize bytes. 444 */ 445 error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio); 446 447 s = splimp(); 448 d->bd_fbuf = d->bd_hbuf; 449 d->bd_hbuf = 0; 450 d->bd_hlen = 0; 451 splx(s); 452 453 return (error); 454 } 455 456 457 /* 458 * If there are processes sleeping on this descriptor, wake them up. 459 */ 460 static inline void 461 bpf_wakeup(d) 462 register struct bpf_d *d; 463 { 464 wakeup((caddr_t)d); 465 #if BSD >= 199103 466 selwakeup(&d->bd_sel); 467 /* XXX */ 468 d->bd_sel.si_pid = 0; 469 #else 470 if (d->bd_selproc) { 471 selwakeup(d->bd_selproc, (int)d->bd_selcoll); 472 d->bd_selcoll = 0; 473 d->bd_selproc = 0; 474 } 475 #endif 476 } 477 478 int 479 bpfwrite(dev, uio) 480 dev_t dev; 481 struct uio *uio; 482 { 483 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 484 struct ifnet *ifp; 485 struct mbuf *m; 486 int error, s; 487 static struct sockaddr dst; 488 int datlen; 489 490 if (d->bd_bif == 0) 491 return (ENXIO); 492 493 ifp = d->bd_bif->bif_ifp; 494 495 if (uio->uio_resid == 0) 496 return (0); 497 498 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen); 499 if (error) 500 return (error); 501 502 if (datlen > ifp->if_mtu) 503 return (EMSGSIZE); 504 505 s = splnet(); 506 #if BSD >= 199103 507 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0); 508 #else 509 error = (*ifp->if_output)(ifp, m, &dst); 510 #endif 511 splx(s); 512 /* 513 * The driver frees the mbuf. 514 */ 515 return (error); 516 } 517 518 /* 519 * Reset a descriptor by flushing its packet buffer and clearing the 520 * receive and drop counts. Should be called at splimp. 521 */ 522 static void 523 reset_d(d) 524 struct bpf_d *d; 525 { 526 if (d->bd_hbuf) { 527 /* Free the hold buffer. */ 528 d->bd_fbuf = d->bd_hbuf; 529 d->bd_hbuf = 0; 530 } 531 d->bd_slen = 0; 532 d->bd_hlen = 0; 533 d->bd_rcount = 0; 534 d->bd_dcount = 0; 535 } 536 537 /* 538 * FIONREAD Check for read packet available. 539 * SIOCGIFADDR Get interface address - convenient hook to driver. 540 * BIOCGBLEN Get buffer len [for read()]. 541 * BIOCSETF Set ethernet read filter. 542 * BIOCFLUSH Flush read packet buffer. 543 * BIOCPROMISC Put interface into promiscuous mode. 544 * BIOCGDLT Get link layer type. 545 * BIOCGETIF Get interface name. 546 * BIOCSETIF Set interface. 547 * BIOCSRTIMEOUT Set read timeout. 548 * BIOCGRTIMEOUT Get read timeout. 549 * BIOCGSTATS Get packet stats. 550 * BIOCIMMEDIATE Set immediate mode. 551 * BIOCVERSION Get filter language version. 552 */ 553 /* ARGSUSED */ 554 int 555 bpfioctl(dev, cmd, addr, flag) 556 dev_t dev; 557 int cmd; 558 caddr_t addr; 559 int flag; 560 { 561 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 562 int s, error = 0; 563 564 switch (cmd) { 565 566 default: 567 error = EINVAL; 568 break; 569 570 /* 571 * Check for read packet available. 572 */ 573 case FIONREAD: 574 { 575 int n; 576 577 s = splimp(); 578 n = d->bd_slen; 579 if (d->bd_hbuf) 580 n += d->bd_hlen; 581 splx(s); 582 583 *(int *)addr = n; 584 break; 585 } 586 587 case SIOCGIFADDR: 588 { 589 struct ifnet *ifp; 590 591 if (d->bd_bif == 0) 592 error = EINVAL; 593 else { 594 ifp = d->bd_bif->bif_ifp; 595 error = (*ifp->if_ioctl)(ifp, cmd, addr); 596 } 597 break; 598 } 599 600 /* 601 * Get buffer len [for read()]. 602 */ 603 case BIOCGBLEN: 604 *(u_int *)addr = d->bd_bufsize; 605 break; 606 607 /* 608 * Set buffer length. 609 */ 610 case BIOCSBLEN: 611 #if BSD < 199103 612 error = EINVAL; 613 #else 614 if (d->bd_bif != 0) 615 error = EINVAL; 616 else { 617 register u_int size = *(u_int *)addr; 618 619 if (size > BPF_MAXBUFSIZE) 620 *(u_int *)addr = size = BPF_MAXBUFSIZE; 621 else if (size < BPF_MINBUFSIZE) 622 *(u_int *)addr = size = BPF_MINBUFSIZE; 623 d->bd_bufsize = size; 624 } 625 #endif 626 break; 627 628 /* 629 * Set link layer read filter. 630 */ 631 case BIOCSETF: 632 error = bpf_setf(d, (struct bpf_program *)addr); 633 break; 634 635 /* 636 * Flush read packet buffer. 637 */ 638 case BIOCFLUSH: 639 s = splimp(); 640 reset_d(d); 641 splx(s); 642 break; 643 644 /* 645 * Put interface into promiscuous mode. 646 */ 647 case BIOCPROMISC: 648 if (d->bd_bif == 0) { 649 /* 650 * No interface attached yet. 651 */ 652 error = EINVAL; 653 break; 654 } 655 s = splimp(); 656 if (d->bd_promisc == 0) { 657 error = ifpromisc(d->bd_bif->bif_ifp, 1); 658 if (error == 0) 659 d->bd_promisc = 1; 660 } 661 splx(s); 662 break; 663 664 /* 665 * Get device parameters. 666 */ 667 case BIOCGDLT: 668 if (d->bd_bif == 0) 669 error = EINVAL; 670 else 671 *(u_int *)addr = d->bd_bif->bif_dlt; 672 break; 673 674 /* 675 * Set interface name. 676 */ 677 case BIOCGETIF: 678 if (d->bd_bif == 0) 679 error = EINVAL; 680 else 681 bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr); 682 break; 683 684 /* 685 * Set interface. 686 */ 687 case BIOCSETIF: 688 error = bpf_setif(d, (struct ifreq *)addr); 689 break; 690 691 /* 692 * Set read timeout. 693 */ 694 case BIOCSRTIMEOUT: 695 { 696 struct timeval *tv = (struct timeval *)addr; 697 u_long msec; 698 699 /* Compute number of milliseconds. */ 700 msec = tv->tv_sec * 1000 + tv->tv_usec / 1000; 701 /* Scale milliseconds to ticks. Assume hard 702 clock has millisecond or greater resolution 703 (i.e. tick >= 1000). For 10ms hardclock, 704 tick/1000 = 10, so rtout<-msec/10. */ 705 d->bd_rtout = msec / (tick / 1000); 706 break; 707 } 708 709 /* 710 * Get read timeout. 711 */ 712 case BIOCGRTIMEOUT: 713 { 714 struct timeval *tv = (struct timeval *)addr; 715 u_long msec = d->bd_rtout; 716 717 msec *= tick / 1000; 718 tv->tv_sec = msec / 1000; 719 tv->tv_usec = msec % 1000; 720 break; 721 } 722 723 /* 724 * Get packet stats. 725 */ 726 case BIOCGSTATS: 727 { 728 struct bpf_stat *bs = (struct bpf_stat *)addr; 729 730 bs->bs_recv = d->bd_rcount; 731 bs->bs_drop = d->bd_dcount; 732 break; 733 } 734 735 /* 736 * Set immediate mode. 737 */ 738 case BIOCIMMEDIATE: 739 d->bd_immediate = *(u_int *)addr; 740 break; 741 742 case BIOCVERSION: 743 { 744 struct bpf_version *bv = (struct bpf_version *)addr; 745 746 bv->bv_major = BPF_MAJOR_VERSION; 747 bv->bv_minor = BPF_MINOR_VERSION; 748 break; 749 } 750 } 751 return (error); 752 } 753 754 /* 755 * Set d's packet filter program to fp. If this file already has a filter, 756 * free it and replace it. Returns EINVAL for bogus requests. 757 */ 758 int 759 bpf_setf(d, fp) 760 struct bpf_d *d; 761 struct bpf_program *fp; 762 { 763 struct bpf_insn *fcode, *old; 764 u_int flen, size; 765 int s; 766 767 old = d->bd_filter; 768 if (fp->bf_insns == 0) { 769 if (fp->bf_len != 0) 770 return (EINVAL); 771 s = splimp(); 772 d->bd_filter = 0; 773 reset_d(d); 774 splx(s); 775 if (old != 0) 776 free((caddr_t)old, M_DEVBUF); 777 return (0); 778 } 779 flen = fp->bf_len; 780 if (flen > BPF_MAXINSNS) 781 return (EINVAL); 782 783 size = flen * sizeof(*fp->bf_insns); 784 fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK); 785 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 786 bpf_validate(fcode, (int)flen)) { 787 s = splimp(); 788 d->bd_filter = fcode; 789 reset_d(d); 790 splx(s); 791 if (old != 0) 792 free((caddr_t)old, M_DEVBUF); 793 794 return (0); 795 } 796 free((caddr_t)fcode, M_DEVBUF); 797 return (EINVAL); 798 } 799 800 /* 801 * Detach a file from its current interface (if attached at all) and attach 802 * to the interface indicated by the name stored in ifr. 803 * Return an errno or 0. 804 */ 805 static int 806 bpf_setif(d, ifr) 807 struct bpf_d *d; 808 struct ifreq *ifr; 809 { 810 struct bpf_if *bp; 811 char *cp; 812 int unit, s, error; 813 814 /* 815 * Separate string into name part and unit number. Put a null 816 * byte at the end of the name part, and compute the number. 817 * If the a unit number is unspecified, the default is 0, 818 * as initialized above. XXX This should be common code. 819 */ 820 unit = 0; 821 cp = ifr->ifr_name; 822 cp[sizeof(ifr->ifr_name) - 1] = '\0'; 823 while (*cp++) { 824 if (*cp >= '0' && *cp <= '9') { 825 unit = *cp - '0'; 826 *cp++ = '\0'; 827 while (*cp) 828 unit = 10 * unit + *cp++ - '0'; 829 break; 830 } 831 } 832 /* 833 * Look through attached interfaces for the named one. 834 */ 835 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 836 struct ifnet *ifp = bp->bif_ifp; 837 838 if (ifp == 0 || unit != ifp->if_unit 839 || strcmp(ifp->if_name, ifr->ifr_name) != 0) 840 continue; 841 /* 842 * We found the requested interface. 843 * If it's not up, return an error. 844 * Allocate the packet buffers if we need to. 845 * If we're already attached to requested interface, 846 * just flush the buffer. 847 */ 848 if ((ifp->if_flags & IFF_UP) == 0) 849 return (ENETDOWN); 850 851 if (d->bd_sbuf == 0) { 852 error = bpf_allocbufs(d); 853 if (error != 0) 854 return (error); 855 } 856 s = splimp(); 857 if (bp != d->bd_bif) { 858 if (d->bd_bif) 859 /* 860 * Detach if attached to something else. 861 */ 862 bpf_detachd(d); 863 864 bpf_attachd(d, bp); 865 } 866 reset_d(d); 867 splx(s); 868 return (0); 869 } 870 /* Not found. */ 871 return (ENXIO); 872 } 873 874 /* 875 * Convert an interface name plus unit number of an ifp to a single 876 * name which is returned in the ifr. 877 */ 878 static void 879 bpf_ifname(ifp, ifr) 880 struct ifnet *ifp; 881 struct ifreq *ifr; 882 { 883 char *s = ifp->if_name; 884 char *d = ifr->ifr_name; 885 886 while (*d++ = *s++) 887 continue; 888 /* XXX Assume that unit number is less than 10. */ 889 *d++ = ifp->if_unit + '0'; 890 *d = '\0'; 891 } 892 893 /* 894 * The new select interface passes down the proc pointer; the old select 895 * stubs had to grab it out of the user struct. This glue allows either case. 896 */ 897 #if BSD >= 199103 898 #define bpf_select bpfselect 899 #else 900 int 901 bpfselect(dev, rw) 902 register dev_t dev; 903 int rw; 904 { 905 return (bpf_select(dev, rw, u.u_procp)); 906 } 907 #endif 908 909 /* 910 * Support for select() system call 911 * Inspired by the code in tty.c for the same purpose. 912 * 913 * Return true iff the specific operation will not block indefinitely. 914 * Otherwise, return false but make a note that a selwakeup() must be done. 915 */ 916 int 917 bpf_select(dev, rw, p) 918 register dev_t dev; 919 int rw; 920 struct proc *p; 921 { 922 register struct bpf_d *d; 923 register int s; 924 925 if (rw != FREAD) 926 return (0); 927 /* 928 * An imitation of the FIONREAD ioctl code. 929 */ 930 d = &bpf_dtab[minor(dev)]; 931 932 s = splimp(); 933 if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) { 934 /* 935 * There is data waiting. 936 */ 937 splx(s); 938 return (1); 939 } 940 #if BSD >= 199103 941 selrecord(p, &d->bd_sel); 942 #else 943 /* 944 * No data ready. If there's already a select() waiting on this 945 * minor device then this is a collision. This shouldn't happen 946 * because minors really should not be shared, but if a process 947 * forks while one of these is open, it is possible that both 948 * processes could select on the same descriptor. 949 */ 950 if (d->bd_selproc && d->bd_selproc->p_wchan == (caddr_t)&selwait) 951 d->bd_selcoll = 1; 952 else 953 d->bd_selproc = p; 954 #endif 955 splx(s); 956 return (0); 957 } 958 959 /* 960 * Incoming linkage from device drivers. Process the packet pkt, of length 961 * pktlen, which is stored in a contiguous buffer. The packet is parsed 962 * by each process' filter, and if accepted, stashed into the corresponding 963 * buffer. 964 */ 965 void 966 bpf_tap(arg, pkt, pktlen) 967 caddr_t arg; 968 register u_char *pkt; 969 register u_int pktlen; 970 { 971 struct bpf_if *bp; 972 register struct bpf_d *d; 973 register u_int slen; 974 /* 975 * Note that the ipl does not have to be raised at this point. 976 * The only problem that could arise here is that if two different 977 * interfaces shared any data. This is not the case. 978 */ 979 bp = (struct bpf_if *)arg; 980 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 981 ++d->bd_rcount; 982 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); 983 if (slen != 0) 984 catchpacket(d, pkt, pktlen, slen, bcopy); 985 } 986 } 987 988 /* 989 * Copy data from an mbuf chain into a buffer. This code is derived 990 * from m_copydata in sys/uipc_mbuf.c. 991 */ 992 static void 993 bpf_mcopy(src, dst, len) 994 u_char *src; 995 u_char *dst; 996 register int len; 997 { 998 register struct mbuf *m = (struct mbuf *)src; 999 register unsigned count; 1000 1001 while (len > 0) { 1002 if (m == 0) 1003 panic("bpf_mcopy"); 1004 count = min(m->m_len, len); 1005 bcopy(mtod(m, caddr_t), (caddr_t)dst, count); 1006 m = m->m_next; 1007 dst += count; 1008 len -= count; 1009 } 1010 } 1011 1012 /* 1013 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1014 */ 1015 void 1016 bpf_mtap(arg, m) 1017 caddr_t arg; 1018 struct mbuf *m; 1019 { 1020 struct bpf_if *bp = (struct bpf_if *)arg; 1021 struct bpf_d *d; 1022 u_int pktlen, slen; 1023 struct mbuf *m0; 1024 1025 pktlen = 0; 1026 for (m0 = m; m0 != 0; m0 = m0->m_next) 1027 pktlen += m0->m_len; 1028 1029 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1030 ++d->bd_rcount; 1031 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); 1032 if (slen != 0) 1033 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); 1034 } 1035 } 1036 1037 /* 1038 * Move the packet data from interface memory (pkt) into the 1039 * store buffer. Return 1 if it's time to wakeup a listener (buffer full), 1040 * otherwise 0. "copy" is the routine called to do the actual data 1041 * transfer. bcopy is passed in to copy contiguous chunks, while 1042 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1043 * pkt is really an mbuf. 1044 */ 1045 static void 1046 catchpacket(d, pkt, pktlen, snaplen, cpfn) 1047 register struct bpf_d *d; 1048 register u_char *pkt; 1049 register u_int pktlen, snaplen; 1050 register void (*cpfn)(); 1051 { 1052 register struct bpf_hdr *hp; 1053 register int totlen, curlen; 1054 register int hdrlen = d->bd_bif->bif_hdrlen; 1055 /* 1056 * Figure out how many bytes to move. If the packet is 1057 * greater or equal to the snapshot length, transfer that 1058 * much. Otherwise, transfer the whole packet (unless 1059 * we hit the buffer size limit). 1060 */ 1061 totlen = hdrlen + min(snaplen, pktlen); 1062 if (totlen > d->bd_bufsize) 1063 totlen = d->bd_bufsize; 1064 1065 /* 1066 * Round up the end of the previous packet to the next longword. 1067 */ 1068 curlen = BPF_WORDALIGN(d->bd_slen); 1069 if (curlen + totlen > d->bd_bufsize) { 1070 /* 1071 * This packet will overflow the storage buffer. 1072 * Rotate the buffers if we can, then wakeup any 1073 * pending reads. 1074 */ 1075 if (d->bd_fbuf == 0) { 1076 /* 1077 * We haven't completed the previous read yet, 1078 * so drop the packet. 1079 */ 1080 ++d->bd_dcount; 1081 return; 1082 } 1083 ROTATE_BUFFERS(d); 1084 bpf_wakeup(d); 1085 curlen = 0; 1086 } 1087 else if (d->bd_immediate) 1088 /* 1089 * Immediate mode is set. A packet arrived so any 1090 * reads should be woken up. 1091 */ 1092 bpf_wakeup(d); 1093 1094 /* 1095 * Append the bpf header. 1096 */ 1097 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1098 #if BSD >= 199103 1099 microtime(&hp->bh_tstamp); 1100 #elif defined(sun) 1101 uniqtime(&hp->bh_tstamp); 1102 #else 1103 hp->bh_tstamp = time; 1104 #endif 1105 hp->bh_datalen = pktlen; 1106 hp->bh_hdrlen = hdrlen; 1107 /* 1108 * Copy the packet data into the store buffer and update its length. 1109 */ 1110 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1111 d->bd_slen = curlen + totlen; 1112 } 1113 1114 /* 1115 * Initialize all nonzero fields of a descriptor. 1116 */ 1117 static int 1118 bpf_allocbufs(d) 1119 register struct bpf_d *d; 1120 { 1121 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1122 if (d->bd_fbuf == 0) 1123 return (ENOBUFS); 1124 1125 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1126 if (d->bd_sbuf == 0) { 1127 free(d->bd_fbuf, M_DEVBUF); 1128 return (ENOBUFS); 1129 } 1130 d->bd_slen = 0; 1131 d->bd_hlen = 0; 1132 return (0); 1133 } 1134 1135 /* 1136 * Free buffers currently in use by a descriptor. 1137 * Called on close. 1138 */ 1139 static void 1140 bpf_freed(d) 1141 register struct bpf_d *d; 1142 { 1143 /* 1144 * We don't need to lock out interrupts since this descriptor has 1145 * been detached from its interface and it yet hasn't been marked 1146 * free. 1147 */ 1148 if (d->bd_sbuf != 0) { 1149 free(d->bd_sbuf, M_DEVBUF); 1150 if (d->bd_hbuf != 0) 1151 free(d->bd_hbuf, M_DEVBUF); 1152 if (d->bd_fbuf != 0) 1153 free(d->bd_fbuf, M_DEVBUF); 1154 } 1155 if (d->bd_filter) 1156 free((caddr_t)d->bd_filter, M_DEVBUF); 1157 1158 D_MARKFREE(d); 1159 } 1160 1161 /* 1162 * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *) 1163 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed 1164 * size of the link header (variable length headers not yet supported). 1165 */ 1166 void 1167 bpfattach(driverp, ifp, dlt, hdrlen) 1168 caddr_t *driverp; 1169 struct ifnet *ifp; 1170 u_int dlt, hdrlen; 1171 { 1172 struct bpf_if *bp; 1173 int i; 1174 #if BSD < 199103 1175 static struct bpf_if bpf_ifs[NBPFILTER]; 1176 static int bpfifno; 1177 1178 bp = (bpfifno < NBPFILTER) ? &bpf_ifs[bpfifno++] : 0; 1179 #else 1180 bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1181 #endif 1182 if (bp == 0) 1183 panic("bpfattach"); 1184 1185 bp->bif_dlist = 0; 1186 bp->bif_driverp = (struct bpf_if **)driverp; 1187 bp->bif_ifp = ifp; 1188 bp->bif_dlt = dlt; 1189 1190 bp->bif_next = bpf_iflist; 1191 bpf_iflist = bp; 1192 1193 *bp->bif_driverp = 0; 1194 1195 /* 1196 * Compute the length of the bpf header. This is not necessarily 1197 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1198 * that the network layer header begins on a longword boundary (for 1199 * performance reasons and to alleviate alignment restrictions). 1200 */ 1201 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1202 1203 /* 1204 * Mark all the descriptors free if this hasn't been done. 1205 */ 1206 if (!D_ISFREE(&bpf_dtab[0])) 1207 for (i = 0; i < NBPFILTER; ++i) 1208 D_MARKFREE(&bpf_dtab[i]); 1209 1210 printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit); 1211 } 1212 1213 #if BSD >= 199103 1214 /* XXX This routine belongs in net/if.c. */ 1215 /* 1216 * Set/clear promiscuous mode on interface ifp based on the truth value 1217 * of pswitch. The calls are reference counted so that only the first 1218 * "on" request actually has an effect, as does the final "off" request. 1219 * Results are undefined if the "off" and "on" requests are not matched. 1220 */ 1221 int 1222 ifpromisc(ifp, pswitch) 1223 struct ifnet *ifp; 1224 int pswitch; 1225 { 1226 struct ifreq ifr; 1227 /* 1228 * If the device is not configured up, we cannot put it in 1229 * promiscuous mode. 1230 */ 1231 if ((ifp->if_flags & IFF_UP) == 0) 1232 return (ENETDOWN); 1233 1234 if (pswitch) { 1235 if (ifp->if_pcount++ != 0) 1236 return (0); 1237 ifp->if_flags |= IFF_PROMISC; 1238 } else { 1239 if (--ifp->if_pcount > 0) 1240 return (0); 1241 ifp->if_flags &= ~IFF_PROMISC; 1242 } 1243 ifr.ifr_flags = ifp->if_flags; 1244 return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr)); 1245 } 1246 #endif 1247 1248 #if BSD < 199103 1249 /* 1250 * Allocate some memory for bpf. This is temporary SunOS support, and 1251 * is admittedly a hack. 1252 * If resources unavaiable, return 0. 1253 */ 1254 static caddr_t 1255 bpf_alloc(size, canwait) 1256 register int size; 1257 register int canwait; 1258 { 1259 register struct mbuf *m; 1260 1261 if ((unsigned)size > (MCLBYTES-8)) 1262 return 0; 1263 1264 MGET(m, canwait, MT_DATA); 1265 if (m == 0) 1266 return 0; 1267 if ((unsigned)size > (MLEN-8)) { 1268 MCLGET(m); 1269 if (m->m_len != MCLBYTES) { 1270 m_freem(m); 1271 return 0; 1272 } 1273 } 1274 *mtod(m, struct mbuf **) = m; 1275 return mtod(m, caddr_t) + 8; 1276 } 1277 #endif 1278 #endif 1279