1 /* 2 * Copyright (c) 1990, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from the Stanford/CMU enet packet filter, 6 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 7 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 8 * Berkeley Laboratory. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * from: @(#)bpf.c 8.2 (Berkeley) 3/28/94 39 * $Id: bpf.c,v 1.12 1994/05/13 06:02:14 mycroft Exp $ 40 */ 41 42 #include "bpfilter.h" 43 44 #ifndef __GNUC__ 45 #define inline 46 #else 47 #define inline __inline 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/time.h> 55 #include <sys/proc.h> 56 #include <sys/user.h> 57 #include <sys/ioctl.h> 58 #include <sys/map.h> 59 60 #include <sys/file.h> 61 #if defined(sparc) && BSD < 199103 62 #include <sys/stream.h> 63 #endif 64 #include <sys/tty.h> 65 #include <sys/uio.h> 66 67 #include <sys/protosw.h> 68 #include <sys/socket.h> 69 #include <net/if.h> 70 71 #include <net/bpf.h> 72 #include <net/bpfdesc.h> 73 74 #include <sys/errno.h> 75 76 #include <netinet/in.h> 77 #include <netinet/if_ether.h> 78 #include <sys/kernel.h> 79 80 /* 81 * Older BSDs don't have kernel malloc. 82 */ 83 #if BSD < 199103 84 extern bcopy(); 85 static caddr_t bpf_alloc(); 86 #include <net/bpf_compat.h> 87 #define BPF_BUFSIZE (MCLBYTES-8) 88 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, code, uio) 89 #else 90 #define BPF_BUFSIZE 4096 91 #define UIOMOVE(cp, len, code, uio) uiomove(cp, len, uio) 92 #endif 93 94 #define PRINET 26 /* interruptible */ 95 96 /* 97 * The default read buffer size is patchable. 98 */ 99 int bpf_bufsize = BPF_BUFSIZE; 100 101 /* 102 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 103 * bpf_dtab holds the descriptors, indexed by minor device # 104 */ 105 struct bpf_if *bpf_iflist; 106 struct bpf_d bpf_dtab[NBPFILTER]; 107 108 #if BSD >= 199207 || NetBSD0_9 >= 2 109 /* 110 * bpfilterattach() is called at boot time in new systems. We do 111 * nothing here since old systems will not call this. 112 */ 113 /* ARGSUSED */ 114 void 115 bpfilterattach(n) 116 int n; 117 { 118 } 119 #endif 120 121 static int bpf_allocbufs __P((struct bpf_d *)); 122 static int bpf_allocbufs __P((struct bpf_d *)); 123 static void bpf_freed __P((struct bpf_d *)); 124 static void bpf_freed __P((struct bpf_d *)); 125 static void bpf_ifname __P((struct ifnet *, struct ifreq *)); 126 static void bpf_ifname __P((struct ifnet *, struct ifreq *)); 127 static void bpf_mcopy __P((const void *, void *, u_int)); 128 static int bpf_movein __P((struct uio *, int, 129 struct mbuf **, struct sockaddr *, int *)); 130 static int bpf_setif __P((struct bpf_d *, struct ifreq *)); 131 static int bpf_setif __P((struct bpf_d *, struct ifreq *)); 132 static inline void 133 bpf_wakeup __P((struct bpf_d *)); 134 static void catchpacket __P((struct bpf_d *, u_char *, u_int, 135 u_int, void (*)(const void *, void *, u_int))); 136 static void reset_d __P((struct bpf_d *)); 137 138 static int 139 bpf_movein(uio, linktype, mp, sockp, datlen) 140 register struct uio *uio; 141 int linktype, *datlen; 142 register struct mbuf **mp; 143 register struct sockaddr *sockp; 144 { 145 struct mbuf *m; 146 int error; 147 int len; 148 int hlen; 149 150 /* 151 * Build a sockaddr based on the data link layer type. 152 * We do this at this level because the ethernet header 153 * is copied directly into the data field of the sockaddr. 154 * In the case of SLIP, there is no header and the packet 155 * is forwarded as is. 156 * Also, we are careful to leave room at the front of the mbuf 157 * for the link level header. 158 */ 159 switch (linktype) { 160 161 case DLT_SLIP: 162 sockp->sa_family = AF_INET; 163 hlen = 0; 164 break; 165 166 case DLT_PPP: 167 sockp->sa_family = AF_UNSPEC; 168 hlen = 0; 169 break; 170 171 case DLT_EN10MB: 172 sockp->sa_family = AF_UNSPEC; 173 /* XXX Would MAXLINKHDR be better? */ 174 hlen = sizeof(struct ether_header); 175 break; 176 177 case DLT_FDDI: 178 sockp->sa_family = AF_UNSPEC; 179 /* XXX 4(FORMAC)+6(dst)+6(src)+3(LLC)+5(SNAP) */ 180 hlen = 24; 181 break; 182 183 case DLT_NULL: 184 sockp->sa_family = AF_UNSPEC; 185 hlen = 0; 186 break; 187 188 default: 189 return (EIO); 190 } 191 192 len = uio->uio_resid; 193 *datlen = len - hlen; 194 if ((unsigned)len > MCLBYTES) 195 return (EIO); 196 197 MGET(m, M_WAIT, MT_DATA); 198 if (m == 0) 199 return (ENOBUFS); 200 if (len > MLEN) { 201 #if BSD >= 199103 202 MCLGET(m, M_WAIT); 203 if ((m->m_flags & M_EXT) == 0) { 204 #else 205 MCLGET(m); 206 if (m->m_len != MCLBYTES) { 207 #endif 208 error = ENOBUFS; 209 goto bad; 210 } 211 } 212 m->m_len = len; 213 *mp = m; 214 /* 215 * Make room for link header. 216 */ 217 if (hlen != 0) { 218 m->m_len -= hlen; 219 #if BSD >= 199103 220 m->m_data += hlen; /* XXX */ 221 #else 222 m->m_off += hlen; 223 #endif 224 error = UIOMOVE((caddr_t)sockp->sa_data, hlen, UIO_WRITE, uio); 225 if (error) 226 goto bad; 227 } 228 error = UIOMOVE(mtod(m, caddr_t), len - hlen, UIO_WRITE, uio); 229 if (!error) 230 return (0); 231 bad: 232 m_freem(m); 233 return (error); 234 } 235 236 /* 237 * Attach file to the bpf interface, i.e. make d listen on bp. 238 * Must be called at splimp. 239 */ 240 static void 241 bpf_attachd(d, bp) 242 struct bpf_d *d; 243 struct bpf_if *bp; 244 { 245 /* 246 * Point d at bp, and add d to the interface's list of listeners. 247 * Finally, point the driver's bpf cookie at the interface so 248 * it will divert packets to bpf. 249 */ 250 d->bd_bif = bp; 251 d->bd_next = bp->bif_dlist; 252 bp->bif_dlist = d; 253 254 *bp->bif_driverp = bp; 255 } 256 257 /* 258 * Detach a file from its interface. 259 */ 260 static void 261 bpf_detachd(d) 262 struct bpf_d *d; 263 { 264 struct bpf_d **p; 265 struct bpf_if *bp; 266 267 bp = d->bd_bif; 268 /* 269 * Check if this descriptor had requested promiscuous mode. 270 * If so, turn it off. 271 */ 272 if (d->bd_promisc) { 273 d->bd_promisc = 0; 274 if (ifpromisc(bp->bif_ifp, 0)) 275 /* 276 * Something is really wrong if we were able to put 277 * the driver into promiscuous mode, but can't 278 * take it out. 279 */ 280 panic("bpf: ifpromisc failed"); 281 } 282 /* Remove d from the interface's descriptor list. */ 283 p = &bp->bif_dlist; 284 while (*p != d) { 285 p = &(*p)->bd_next; 286 if (*p == 0) 287 panic("bpf_detachd: descriptor not in list"); 288 } 289 *p = (*p)->bd_next; 290 if (bp->bif_dlist == 0) 291 /* 292 * Let the driver know that there are no more listeners. 293 */ 294 *d->bd_bif->bif_driverp = 0; 295 d->bd_bif = 0; 296 } 297 298 299 /* 300 * Mark a descriptor free by making it point to itself. 301 * This is probably cheaper than marking with a constant since 302 * the address should be in a register anyway. 303 */ 304 #define D_ISFREE(d) ((d) == (d)->bd_next) 305 #define D_MARKFREE(d) ((d)->bd_next = (d)) 306 #define D_MARKUSED(d) ((d)->bd_next = 0) 307 308 /* 309 * Open ethernet device. Returns ENXIO for illegal minor device number, 310 * EBUSY if file is open by another process. 311 */ 312 /* ARGSUSED */ 313 int 314 bpfopen(dev, flag) 315 dev_t dev; 316 int flag; 317 { 318 register struct bpf_d *d; 319 320 if (minor(dev) >= NBPFILTER) 321 return (ENXIO); 322 /* 323 * Each minor can be opened by only one process. If the requested 324 * minor is in use, return EBUSY. 325 */ 326 d = &bpf_dtab[minor(dev)]; 327 if (!D_ISFREE(d)) 328 return (EBUSY); 329 330 /* Mark "free" and do most initialization. */ 331 bzero((char *)d, sizeof(*d)); 332 d->bd_bufsize = bpf_bufsize; 333 334 return (0); 335 } 336 337 /* 338 * Close the descriptor by detaching it from its interface, 339 * deallocating its buffers, and marking it free. 340 */ 341 /* ARGSUSED */ 342 int 343 bpfclose(dev, flag) 344 dev_t dev; 345 int flag; 346 { 347 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 348 register int s; 349 350 s = splimp(); 351 if (d->bd_bif) 352 bpf_detachd(d); 353 splx(s); 354 bpf_freed(d); 355 356 return (0); 357 } 358 359 /* 360 * Support for SunOS, which does not have tsleep. 361 */ 362 #if BSD < 199103 363 static 364 bpf_timeout(arg) 365 caddr_t arg; 366 { 367 struct bpf_d *d = (struct bpf_d *)arg; 368 d->bd_timedout = 1; 369 wakeup(arg); 370 } 371 372 #define BPF_SLEEP(chan, pri, s, t) bpf_sleep((struct bpf_d *)chan) 373 374 int 375 bpf_sleep(d) 376 register struct bpf_d *d; 377 { 378 register int rto = d->bd_rtout; 379 register int st; 380 381 if (rto != 0) { 382 d->bd_timedout = 0; 383 timeout(bpf_timeout, (caddr_t)d, rto); 384 } 385 st = sleep((caddr_t)d, PRINET|PCATCH); 386 if (rto != 0) { 387 if (d->bd_timedout == 0) 388 untimeout(bpf_timeout, (caddr_t)d); 389 else if (st == 0) 390 return EWOULDBLOCK; 391 } 392 return (st != 0) ? EINTR : 0; 393 } 394 #else 395 #define BPF_SLEEP tsleep 396 #endif 397 398 /* 399 * Rotate the packet buffers in descriptor d. Move the store buffer 400 * into the hold slot, and the free buffer into the store slot. 401 * Zero the length of the new store buffer. 402 */ 403 #define ROTATE_BUFFERS(d) \ 404 (d)->bd_hbuf = (d)->bd_sbuf; \ 405 (d)->bd_hlen = (d)->bd_slen; \ 406 (d)->bd_sbuf = (d)->bd_fbuf; \ 407 (d)->bd_slen = 0; \ 408 (d)->bd_fbuf = 0; 409 /* 410 * bpfread - read next chunk of packets from buffers 411 */ 412 int 413 bpfread(dev, uio) 414 dev_t dev; 415 register struct uio *uio; 416 { 417 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 418 int error; 419 int s; 420 421 /* 422 * Restrict application to use a buffer the same size as 423 * as kernel buffers. 424 */ 425 if (uio->uio_resid != d->bd_bufsize) 426 return (EINVAL); 427 428 s = splimp(); 429 /* 430 * If the hold buffer is empty, then do a timed sleep, which 431 * ends when the timeout expires or when enough packets 432 * have arrived to fill the store buffer. 433 */ 434 while (d->bd_hbuf == 0) { 435 if (d->bd_immediate && d->bd_slen != 0) { 436 /* 437 * A packet(s) either arrived since the previous 438 * read or arrived while we were asleep. 439 * Rotate the buffers and return what's here. 440 */ 441 ROTATE_BUFFERS(d); 442 break; 443 } 444 error = BPF_SLEEP((caddr_t)d, PRINET|PCATCH, "bpf", 445 d->bd_rtout); 446 if (error == EINTR || error == ERESTART) { 447 splx(s); 448 return (error); 449 } 450 if (error == EWOULDBLOCK) { 451 /* 452 * On a timeout, return what's in the buffer, 453 * which may be nothing. If there is something 454 * in the store buffer, we can rotate the buffers. 455 */ 456 if (d->bd_hbuf) 457 /* 458 * We filled up the buffer in between 459 * getting the timeout and arriving 460 * here, so we don't need to rotate. 461 */ 462 break; 463 464 if (d->bd_slen == 0) { 465 splx(s); 466 return (0); 467 } 468 ROTATE_BUFFERS(d); 469 break; 470 } 471 } 472 /* 473 * At this point, we know we have something in the hold slot. 474 */ 475 splx(s); 476 477 /* 478 * Move data from hold buffer into user space. 479 * We know the entire buffer is transferred since 480 * we checked above that the read buffer is bpf_bufsize bytes. 481 */ 482 error = UIOMOVE(d->bd_hbuf, d->bd_hlen, UIO_READ, uio); 483 484 s = splimp(); 485 d->bd_fbuf = d->bd_hbuf; 486 d->bd_hbuf = 0; 487 d->bd_hlen = 0; 488 splx(s); 489 490 return (error); 491 } 492 493 494 /* 495 * If there are processes sleeping on this descriptor, wake them up. 496 */ 497 static inline void 498 bpf_wakeup(d) 499 register struct bpf_d *d; 500 { 501 wakeup((caddr_t)d); 502 #if BSD >= 199103 503 selwakeup(&d->bd_sel); 504 /* XXX */ 505 d->bd_sel.si_pid = 0; 506 #else 507 if (d->bd_selproc) { 508 selwakeup(d->bd_selproc, (int)d->bd_selcoll); 509 d->bd_selcoll = 0; 510 d->bd_selproc = 0; 511 } 512 #endif 513 } 514 515 int 516 bpfwrite(dev, uio) 517 dev_t dev; 518 struct uio *uio; 519 { 520 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 521 struct ifnet *ifp; 522 struct mbuf *m; 523 int error, s; 524 static struct sockaddr dst; 525 int datlen; 526 527 if (d->bd_bif == 0) 528 return (ENXIO); 529 530 ifp = d->bd_bif->bif_ifp; 531 532 if (uio->uio_resid == 0) 533 return (0); 534 535 error = bpf_movein(uio, (int)d->bd_bif->bif_dlt, &m, &dst, &datlen); 536 if (error) 537 return (error); 538 539 if (datlen > ifp->if_mtu) 540 return (EMSGSIZE); 541 542 s = splnet(); 543 #if BSD >= 199103 544 error = (*ifp->if_output)(ifp, m, &dst, (struct rtentry *)0); 545 #else 546 error = (*ifp->if_output)(ifp, m, &dst); 547 #endif 548 splx(s); 549 /* 550 * The driver frees the mbuf. 551 */ 552 return (error); 553 } 554 555 /* 556 * Reset a descriptor by flushing its packet buffer and clearing the 557 * receive and drop counts. Should be called at splimp. 558 */ 559 static void 560 reset_d(d) 561 struct bpf_d *d; 562 { 563 if (d->bd_hbuf) { 564 /* Free the hold buffer. */ 565 d->bd_fbuf = d->bd_hbuf; 566 d->bd_hbuf = 0; 567 } 568 d->bd_slen = 0; 569 d->bd_hlen = 0; 570 d->bd_rcount = 0; 571 d->bd_dcount = 0; 572 } 573 574 /* 575 * FIONREAD Check for read packet available. 576 * SIOCGIFADDR Get interface address - convenient hook to driver. 577 * BIOCGBLEN Get buffer len [for read()]. 578 * BIOCSETF Set ethernet read filter. 579 * BIOCFLUSH Flush read packet buffer. 580 * BIOCPROMISC Put interface into promiscuous mode. 581 * BIOCGDLT Get link layer type. 582 * BIOCGETIF Get interface name. 583 * BIOCSETIF Set interface. 584 * BIOCSRTIMEOUT Set read timeout. 585 * BIOCGRTIMEOUT Get read timeout. 586 * BIOCGSTATS Get packet stats. 587 * BIOCIMMEDIATE Set immediate mode. 588 * BIOCVERSION Get filter language version. 589 */ 590 /* ARGSUSED */ 591 int 592 bpfioctl(dev, cmd, addr, flag) 593 dev_t dev; 594 int cmd; 595 caddr_t addr; 596 int flag; 597 { 598 register struct bpf_d *d = &bpf_dtab[minor(dev)]; 599 int s, error = 0; 600 601 switch (cmd) { 602 603 default: 604 error = EINVAL; 605 break; 606 607 /* 608 * Check for read packet available. 609 */ 610 case FIONREAD: 611 { 612 int n; 613 614 s = splimp(); 615 n = d->bd_slen; 616 if (d->bd_hbuf) 617 n += d->bd_hlen; 618 splx(s); 619 620 *(int *)addr = n; 621 break; 622 } 623 624 case SIOCGIFADDR: 625 { 626 struct ifnet *ifp; 627 628 if (d->bd_bif == 0) 629 error = EINVAL; 630 else { 631 ifp = d->bd_bif->bif_ifp; 632 error = (*ifp->if_ioctl)(ifp, cmd, addr); 633 } 634 break; 635 } 636 637 /* 638 * Get buffer len [for read()]. 639 */ 640 case BIOCGBLEN: 641 *(u_int *)addr = d->bd_bufsize; 642 break; 643 644 /* 645 * Set buffer length. 646 */ 647 case BIOCSBLEN: 648 #if BSD < 199103 649 error = EINVAL; 650 #else 651 if (d->bd_bif != 0) 652 error = EINVAL; 653 else { 654 register u_int size = *(u_int *)addr; 655 656 if (size > BPF_MAXBUFSIZE) 657 *(u_int *)addr = size = BPF_MAXBUFSIZE; 658 else if (size < BPF_MINBUFSIZE) 659 *(u_int *)addr = size = BPF_MINBUFSIZE; 660 d->bd_bufsize = size; 661 } 662 #endif 663 break; 664 665 /* 666 * Set link layer read filter. 667 */ 668 case BIOCSETF: 669 error = bpf_setf(d, (struct bpf_program *)addr); 670 break; 671 672 /* 673 * Flush read packet buffer. 674 */ 675 case BIOCFLUSH: 676 s = splimp(); 677 reset_d(d); 678 splx(s); 679 break; 680 681 /* 682 * Put interface into promiscuous mode. 683 */ 684 case BIOCPROMISC: 685 if (d->bd_bif == 0) { 686 /* 687 * No interface attached yet. 688 */ 689 error = EINVAL; 690 break; 691 } 692 s = splimp(); 693 if (d->bd_promisc == 0) { 694 error = ifpromisc(d->bd_bif->bif_ifp, 1); 695 if (error == 0) 696 d->bd_promisc = 1; 697 } 698 splx(s); 699 break; 700 701 /* 702 * Get device parameters. 703 */ 704 case BIOCGDLT: 705 if (d->bd_bif == 0) 706 error = EINVAL; 707 else 708 *(u_int *)addr = d->bd_bif->bif_dlt; 709 break; 710 711 /* 712 * Set interface name. 713 */ 714 case BIOCGETIF: 715 if (d->bd_bif == 0) 716 error = EINVAL; 717 else 718 bpf_ifname(d->bd_bif->bif_ifp, (struct ifreq *)addr); 719 break; 720 721 /* 722 * Set interface. 723 */ 724 case BIOCSETIF: 725 error = bpf_setif(d, (struct ifreq *)addr); 726 break; 727 728 /* 729 * Set read timeout. 730 */ 731 case BIOCSRTIMEOUT: 732 { 733 struct timeval *tv = (struct timeval *)addr; 734 u_long msec; 735 736 /* Compute number of milliseconds. */ 737 msec = tv->tv_sec * 1000 + tv->tv_usec / 1000; 738 /* Scale milliseconds to ticks. Assume hard 739 clock has millisecond or greater resolution 740 (i.e. tick >= 1000). For 10ms hardclock, 741 tick/1000 = 10, so rtout<-msec/10. */ 742 d->bd_rtout = msec / (tick / 1000); 743 break; 744 } 745 746 /* 747 * Get read timeout. 748 */ 749 case BIOCGRTIMEOUT: 750 { 751 struct timeval *tv = (struct timeval *)addr; 752 u_long msec = d->bd_rtout; 753 754 msec *= tick / 1000; 755 tv->tv_sec = msec / 1000; 756 tv->tv_usec = msec % 1000; 757 break; 758 } 759 760 /* 761 * Get packet stats. 762 */ 763 case BIOCGSTATS: 764 { 765 struct bpf_stat *bs = (struct bpf_stat *)addr; 766 767 bs->bs_recv = d->bd_rcount; 768 bs->bs_drop = d->bd_dcount; 769 break; 770 } 771 772 /* 773 * Set immediate mode. 774 */ 775 case BIOCIMMEDIATE: 776 d->bd_immediate = *(u_int *)addr; 777 break; 778 779 case BIOCVERSION: 780 { 781 struct bpf_version *bv = (struct bpf_version *)addr; 782 783 bv->bv_major = BPF_MAJOR_VERSION; 784 bv->bv_minor = BPF_MINOR_VERSION; 785 break; 786 } 787 } 788 return (error); 789 } 790 791 /* 792 * Set d's packet filter program to fp. If this file already has a filter, 793 * free it and replace it. Returns EINVAL for bogus requests. 794 */ 795 int 796 bpf_setf(d, fp) 797 struct bpf_d *d; 798 struct bpf_program *fp; 799 { 800 struct bpf_insn *fcode, *old; 801 u_int flen, size; 802 int s; 803 804 old = d->bd_filter; 805 if (fp->bf_insns == 0) { 806 if (fp->bf_len != 0) 807 return (EINVAL); 808 s = splimp(); 809 d->bd_filter = 0; 810 reset_d(d); 811 splx(s); 812 if (old != 0) 813 free((caddr_t)old, M_DEVBUF); 814 return (0); 815 } 816 flen = fp->bf_len; 817 if (flen > BPF_MAXINSNS) 818 return (EINVAL); 819 820 size = flen * sizeof(*fp->bf_insns); 821 fcode = (struct bpf_insn *)malloc(size, M_DEVBUF, M_WAITOK); 822 if (copyin((caddr_t)fp->bf_insns, (caddr_t)fcode, size) == 0 && 823 bpf_validate(fcode, (int)flen)) { 824 s = splimp(); 825 d->bd_filter = fcode; 826 reset_d(d); 827 splx(s); 828 if (old != 0) 829 free((caddr_t)old, M_DEVBUF); 830 831 return (0); 832 } 833 free((caddr_t)fcode, M_DEVBUF); 834 return (EINVAL); 835 } 836 837 /* 838 * Detach a file from its current interface (if attached at all) and attach 839 * to the interface indicated by the name stored in ifr. 840 * Return an errno or 0. 841 */ 842 static int 843 bpf_setif(d, ifr) 844 struct bpf_d *d; 845 struct ifreq *ifr; 846 { 847 struct bpf_if *bp; 848 char *cp; 849 int unit, s, error; 850 851 /* 852 * Separate string into name part and unit number. Put a null 853 * byte at the end of the name part, and compute the number. 854 * If the a unit number is unspecified, the default is 0, 855 * as initialized above. XXX This should be common code. 856 */ 857 unit = 0; 858 cp = ifr->ifr_name; 859 cp[sizeof(ifr->ifr_name) - 1] = '\0'; 860 while (*cp++) { 861 if (*cp >= '0' && *cp <= '9') { 862 unit = *cp - '0'; 863 *cp++ = '\0'; 864 while (*cp) 865 unit = 10 * unit + *cp++ - '0'; 866 break; 867 } 868 } 869 /* 870 * Look through attached interfaces for the named one. 871 */ 872 for (bp = bpf_iflist; bp != 0; bp = bp->bif_next) { 873 struct ifnet *ifp = bp->bif_ifp; 874 875 if (ifp == 0 || unit != ifp->if_unit 876 || strcmp(ifp->if_name, ifr->ifr_name) != 0) 877 continue; 878 /* 879 * We found the requested interface. 880 * If it's not up, return an error. 881 * Allocate the packet buffers if we need to. 882 * If we're already attached to requested interface, 883 * just flush the buffer. 884 */ 885 if ((ifp->if_flags & IFF_UP) == 0) 886 return (ENETDOWN); 887 888 if (d->bd_sbuf == 0) { 889 error = bpf_allocbufs(d); 890 if (error != 0) 891 return (error); 892 } 893 s = splimp(); 894 if (bp != d->bd_bif) { 895 if (d->bd_bif) 896 /* 897 * Detach if attached to something else. 898 */ 899 bpf_detachd(d); 900 901 bpf_attachd(d, bp); 902 } 903 reset_d(d); 904 splx(s); 905 return (0); 906 } 907 /* Not found. */ 908 return (ENXIO); 909 } 910 911 /* 912 * Convert an interface name plus unit number of an ifp to a single 913 * name which is returned in the ifr. 914 */ 915 static void 916 bpf_ifname(ifp, ifr) 917 struct ifnet *ifp; 918 struct ifreq *ifr; 919 { 920 char *s = ifp->if_name; 921 char *d = ifr->ifr_name; 922 923 while (*d++ = *s++) 924 continue; 925 /* XXX Assume that unit number is less than 10. */ 926 *d++ = ifp->if_unit + '0'; 927 *d = '\0'; 928 } 929 930 /* 931 * The new select interface passes down the proc pointer; the old select 932 * stubs had to grab it out of the user struct. This glue allows either case. 933 */ 934 #if BSD >= 199103 935 #define bpf_select bpfselect 936 #else 937 int 938 bpfselect(dev, rw) 939 register dev_t dev; 940 int rw; 941 { 942 return (bpf_select(dev, rw, u.u_procp)); 943 } 944 #endif 945 946 /* 947 * Support for select() system call 948 * 949 * Return true iff the specific operation will not block indefinitely. 950 * Otherwise, return false but make a note that a selwakeup() must be done. 951 */ 952 int 953 bpf_select(dev, rw, p) 954 register dev_t dev; 955 int rw; 956 struct proc *p; 957 { 958 register struct bpf_d *d; 959 register int s; 960 961 if (rw != FREAD) 962 return (0); 963 /* 964 * An imitation of the FIONREAD ioctl code. 965 */ 966 d = &bpf_dtab[minor(dev)]; 967 968 s = splimp(); 969 if (d->bd_hlen != 0 || (d->bd_immediate && d->bd_slen != 0)) { 970 /* 971 * There is data waiting. 972 */ 973 splx(s); 974 return (1); 975 } 976 #if BSD >= 199103 977 selrecord(p, &d->bd_sel); 978 #else 979 /* 980 * No data ready. If there's already a select() waiting on this 981 * minor device then this is a collision. This shouldn't happen 982 * because minors really should not be shared, but if a process 983 * forks while one of these is open, it is possible that both 984 * processes could select on the same descriptor. 985 */ 986 if (d->bd_selproc && d->bd_selproc->p_wchan == (caddr_t)&selwait) 987 d->bd_selcoll = 1; 988 else 989 d->bd_selproc = p; 990 #endif 991 splx(s); 992 return (0); 993 } 994 995 /* 996 * Incoming linkage from device drivers. Process the packet pkt, of length 997 * pktlen, which is stored in a contiguous buffer. The packet is parsed 998 * by each process' filter, and if accepted, stashed into the corresponding 999 * buffer. 1000 */ 1001 void 1002 bpf_tap(arg, pkt, pktlen) 1003 caddr_t arg; 1004 register u_char *pkt; 1005 register u_int pktlen; 1006 { 1007 struct bpf_if *bp; 1008 register struct bpf_d *d; 1009 register u_int slen; 1010 /* 1011 * Note that the ipl does not have to be raised at this point. 1012 * The only problem that could arise here is that if two different 1013 * interfaces shared any data. This is not the case. 1014 */ 1015 bp = (struct bpf_if *)arg; 1016 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1017 ++d->bd_rcount; 1018 slen = bpf_filter(d->bd_filter, pkt, pktlen, pktlen); 1019 if (slen != 0) 1020 catchpacket(d, pkt, pktlen, slen, bcopy); 1021 } 1022 } 1023 1024 /* 1025 * Copy data from an mbuf chain into a buffer. This code is derived 1026 * from m_copydata in sys/uipc_mbuf.c. 1027 */ 1028 static void 1029 bpf_mcopy(src_arg, dst_arg, len) 1030 const void *src_arg; 1031 void *dst_arg; 1032 register u_int len; 1033 { 1034 register const struct mbuf *m; 1035 register u_int count; 1036 u_char *dst; 1037 1038 m = src_arg; 1039 dst = dst_arg; 1040 while (len > 0) { 1041 if (m == 0) 1042 panic("bpf_mcopy"); 1043 count = min(m->m_len, len); 1044 bcopy(mtod(m, caddr_t), (caddr_t)dst, count); 1045 m = m->m_next; 1046 dst += count; 1047 len -= count; 1048 } 1049 } 1050 1051 /* 1052 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1053 */ 1054 void 1055 bpf_mtap(arg, m) 1056 caddr_t arg; 1057 struct mbuf *m; 1058 { 1059 struct bpf_if *bp = (struct bpf_if *)arg; 1060 struct bpf_d *d; 1061 u_int pktlen, slen; 1062 struct mbuf *m0; 1063 1064 pktlen = 0; 1065 for (m0 = m; m0 != 0; m0 = m0->m_next) 1066 pktlen += m0->m_len; 1067 1068 for (d = bp->bif_dlist; d != 0; d = d->bd_next) { 1069 ++d->bd_rcount; 1070 slen = bpf_filter(d->bd_filter, (u_char *)m, pktlen, 0); 1071 if (slen != 0) 1072 catchpacket(d, (u_char *)m, pktlen, slen, bpf_mcopy); 1073 } 1074 } 1075 1076 /* 1077 * Move the packet data from interface memory (pkt) into the 1078 * store buffer. Return 1 if it's time to wakeup a listener (buffer full), 1079 * otherwise 0. "copy" is the routine called to do the actual data 1080 * transfer. bcopy is passed in to copy contiguous chunks, while 1081 * bpf_mcopy is passed in to copy mbuf chains. In the latter case, 1082 * pkt is really an mbuf. 1083 */ 1084 static void 1085 catchpacket(d, pkt, pktlen, snaplen, cpfn) 1086 register struct bpf_d *d; 1087 register u_char *pkt; 1088 register u_int pktlen, snaplen; 1089 register void (*cpfn) __P((const void *, void *, u_int)); 1090 { 1091 register struct bpf_hdr *hp; 1092 register int totlen, curlen; 1093 register int hdrlen = d->bd_bif->bif_hdrlen; 1094 /* 1095 * Figure out how many bytes to move. If the packet is 1096 * greater or equal to the snapshot length, transfer that 1097 * much. Otherwise, transfer the whole packet (unless 1098 * we hit the buffer size limit). 1099 */ 1100 totlen = hdrlen + min(snaplen, pktlen); 1101 if (totlen > d->bd_bufsize) 1102 totlen = d->bd_bufsize; 1103 1104 /* 1105 * Round up the end of the previous packet to the next longword. 1106 */ 1107 curlen = BPF_WORDALIGN(d->bd_slen); 1108 if (curlen + totlen > d->bd_bufsize) { 1109 /* 1110 * This packet will overflow the storage buffer. 1111 * Rotate the buffers if we can, then wakeup any 1112 * pending reads. 1113 */ 1114 if (d->bd_fbuf == 0) { 1115 /* 1116 * We haven't completed the previous read yet, 1117 * so drop the packet. 1118 */ 1119 ++d->bd_dcount; 1120 return; 1121 } 1122 ROTATE_BUFFERS(d); 1123 bpf_wakeup(d); 1124 curlen = 0; 1125 } 1126 else if (d->bd_immediate) 1127 /* 1128 * Immediate mode is set. A packet arrived so any 1129 * reads should be woken up. 1130 */ 1131 bpf_wakeup(d); 1132 1133 /* 1134 * Append the bpf header. 1135 */ 1136 hp = (struct bpf_hdr *)(d->bd_sbuf + curlen); 1137 #if BSD >= 199103 1138 microtime(&hp->bh_tstamp); 1139 #elif defined(sun) 1140 uniqtime(&hp->bh_tstamp); 1141 #else 1142 hp->bh_tstamp = time; 1143 #endif 1144 hp->bh_datalen = pktlen; 1145 hp->bh_hdrlen = hdrlen; 1146 /* 1147 * Copy the packet data into the store buffer and update its length. 1148 */ 1149 (*cpfn)(pkt, (u_char *)hp + hdrlen, (hp->bh_caplen = totlen - hdrlen)); 1150 d->bd_slen = curlen + totlen; 1151 } 1152 1153 /* 1154 * Initialize all nonzero fields of a descriptor. 1155 */ 1156 static int 1157 bpf_allocbufs(d) 1158 register struct bpf_d *d; 1159 { 1160 d->bd_fbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1161 if (d->bd_fbuf == 0) 1162 return (ENOBUFS); 1163 1164 d->bd_sbuf = (caddr_t)malloc(d->bd_bufsize, M_DEVBUF, M_WAITOK); 1165 if (d->bd_sbuf == 0) { 1166 free(d->bd_fbuf, M_DEVBUF); 1167 return (ENOBUFS); 1168 } 1169 d->bd_slen = 0; 1170 d->bd_hlen = 0; 1171 return (0); 1172 } 1173 1174 /* 1175 * Free buffers currently in use by a descriptor. 1176 * Called on close. 1177 */ 1178 static void 1179 bpf_freed(d) 1180 register struct bpf_d *d; 1181 { 1182 /* 1183 * We don't need to lock out interrupts since this descriptor has 1184 * been detached from its interface and it yet hasn't been marked 1185 * free. 1186 */ 1187 if (d->bd_sbuf != 0) { 1188 free(d->bd_sbuf, M_DEVBUF); 1189 if (d->bd_hbuf != 0) 1190 free(d->bd_hbuf, M_DEVBUF); 1191 if (d->bd_fbuf != 0) 1192 free(d->bd_fbuf, M_DEVBUF); 1193 } 1194 if (d->bd_filter) 1195 free((caddr_t)d->bd_filter, M_DEVBUF); 1196 1197 D_MARKFREE(d); 1198 } 1199 1200 /* 1201 * Attach an interface to bpf. driverp is a pointer to a (struct bpf_if *) 1202 * in the driver's softc; dlt is the link layer type; hdrlen is the fixed 1203 * size of the link header (variable length headers not yet supported). 1204 */ 1205 void 1206 bpfattach(driverp, ifp, dlt, hdrlen) 1207 caddr_t *driverp; 1208 struct ifnet *ifp; 1209 u_int dlt, hdrlen; 1210 { 1211 struct bpf_if *bp; 1212 int i; 1213 #if BSD < 199103 1214 static struct bpf_if bpf_ifs[NBPFILTER]; 1215 static int bpfifno; 1216 1217 bp = (bpfifno < NBPFILTER) ? &bpf_ifs[bpfifno++] : 0; 1218 #else 1219 bp = (struct bpf_if *)malloc(sizeof(*bp), M_DEVBUF, M_DONTWAIT); 1220 #endif 1221 if (bp == 0) 1222 panic("bpfattach"); 1223 1224 bp->bif_dlist = 0; 1225 bp->bif_driverp = (struct bpf_if **)driverp; 1226 bp->bif_ifp = ifp; 1227 bp->bif_dlt = dlt; 1228 1229 bp->bif_next = bpf_iflist; 1230 bpf_iflist = bp; 1231 1232 *bp->bif_driverp = 0; 1233 1234 /* 1235 * Compute the length of the bpf header. This is not necessarily 1236 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1237 * that the network layer header begins on a longword boundary (for 1238 * performance reasons and to alleviate alignment restrictions). 1239 */ 1240 bp->bif_hdrlen = BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen; 1241 1242 /* 1243 * Mark all the descriptors free if this hasn't been done. 1244 */ 1245 if (!D_ISFREE(&bpf_dtab[0])) 1246 for (i = 0; i < NBPFILTER; ++i) 1247 D_MARKFREE(&bpf_dtab[i]); 1248 1249 #if 0 1250 printf("bpf: %s%d attached\n", ifp->if_name, ifp->if_unit); 1251 #endif 1252 } 1253 1254 #if BSD >= 199103 1255 /* XXX This routine belongs in net/if.c. */ 1256 /* 1257 * Set/clear promiscuous mode on interface ifp based on the truth value 1258 * of pswitch. The calls are reference counted so that only the first 1259 * "on" request actually has an effect, as does the final "off" request. 1260 * Results are undefined if the "off" and "on" requests are not matched. 1261 */ 1262 int 1263 ifpromisc(ifp, pswitch) 1264 struct ifnet *ifp; 1265 int pswitch; 1266 { 1267 struct ifreq ifr; 1268 /* 1269 * If the device is not configured up, we cannot put it in 1270 * promiscuous mode. 1271 */ 1272 if ((ifp->if_flags & IFF_UP) == 0) 1273 return (ENETDOWN); 1274 1275 if (pswitch) { 1276 if (ifp->if_pcount++ != 0) 1277 return (0); 1278 ifp->if_flags |= IFF_PROMISC; 1279 } else { 1280 if (--ifp->if_pcount > 0) 1281 return (0); 1282 ifp->if_flags &= ~IFF_PROMISC; 1283 } 1284 ifr.ifr_flags = ifp->if_flags; 1285 return ((*ifp->if_ioctl)(ifp, SIOCSIFFLAGS, (caddr_t)&ifr)); 1286 } 1287 #endif 1288 1289 #if BSD < 199103 1290 /* 1291 * Allocate some memory for bpf. This is temporary SunOS support, and 1292 * is admittedly a hack. 1293 * If resources unavaiable, return 0. 1294 */ 1295 static caddr_t 1296 bpf_alloc(size, canwait) 1297 register int size; 1298 register int canwait; 1299 { 1300 register struct mbuf *m; 1301 1302 if ((unsigned)size > (MCLBYTES-8)) 1303 return 0; 1304 1305 MGET(m, canwait, MT_DATA); 1306 if (m == 0) 1307 return 0; 1308 if ((unsigned)size > (MLEN-8)) { 1309 MCLGET(m); 1310 if (m->m_len != MCLBYTES) { 1311 m_freem(m); 1312 return 0; 1313 } 1314 } 1315 *mtod(m, struct mbuf **) = m; 1316 return mtod(m, caddr_t) + 8; 1317 } 1318 #endif 1319