bpf.c revision 1.218
1 /* $NetBSD: bpf.c,v 1.218 2017/10/25 08:12:40 maya Exp $ */ 2 3 /* 4 * Copyright (c) 1990, 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from the Stanford/CMU enet packet filter, 8 * (net/enet.c) distributed as part of 4.3BSD, and code contributed 9 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence 10 * Berkeley Laboratory. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)bpf.c 8.4 (Berkeley) 1/9/95 37 * static char rcsid[] = 38 * "Header: bpf.c,v 1.67 96/09/26 22:00:52 leres Exp "; 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.218 2017/10/25 08:12:40 maya Exp $"); 43 44 #if defined(_KERNEL_OPT) 45 #include "opt_bpf.h" 46 #include "sl.h" 47 #include "strip.h" 48 #include "opt_net_mpsafe.h" 49 #endif 50 51 #include <sys/param.h> 52 #include <sys/systm.h> 53 #include <sys/mbuf.h> 54 #include <sys/buf.h> 55 #include <sys/time.h> 56 #include <sys/proc.h> 57 #include <sys/ioctl.h> 58 #include <sys/conf.h> 59 #include <sys/vnode.h> 60 #include <sys/queue.h> 61 #include <sys/stat.h> 62 #include <sys/module.h> 63 #include <sys/atomic.h> 64 #include <sys/cpu.h> 65 66 #include <sys/file.h> 67 #include <sys/filedesc.h> 68 #include <sys/tty.h> 69 #include <sys/uio.h> 70 71 #include <sys/protosw.h> 72 #include <sys/socket.h> 73 #include <sys/errno.h> 74 #include <sys/kernel.h> 75 #include <sys/poll.h> 76 #include <sys/sysctl.h> 77 #include <sys/kauth.h> 78 #include <sys/syslog.h> 79 #include <sys/percpu.h> 80 #include <sys/pserialize.h> 81 #include <sys/lwp.h> 82 83 #include <net/if.h> 84 #include <net/slip.h> 85 86 #include <net/bpf.h> 87 #include <net/bpfdesc.h> 88 #include <net/bpfjit.h> 89 90 #include <net/if_arc.h> 91 #include <net/if_ether.h> 92 93 #include <netinet/in.h> 94 #include <netinet/if_inarp.h> 95 96 97 #include <compat/sys/sockio.h> 98 99 #ifndef BPF_BUFSIZE 100 /* 101 * 4096 is too small for FDDI frames. 8192 is too small for gigabit Ethernet 102 * jumbos (circa 9k), ATM, or Intel gig/10gig ethernet jumbos (16k). 103 */ 104 # define BPF_BUFSIZE 32768 105 #endif 106 107 #define PRINET 26 /* interruptible */ 108 109 /* 110 * The default read buffer size, and limit for BIOCSBLEN, is sysctl'able. 111 * XXX the default values should be computed dynamically based 112 * on available memory size and available mbuf clusters. 113 */ 114 static int bpf_bufsize = BPF_BUFSIZE; 115 static int bpf_maxbufsize = BPF_DFLTBUFSIZE; /* XXX set dynamically, see above */ 116 static bool bpf_jit = false; 117 118 struct bpfjit_ops bpfjit_module_ops = { 119 .bj_generate_code = NULL, 120 .bj_free_code = NULL 121 }; 122 123 /* 124 * Global BPF statistics returned by net.bpf.stats sysctl. 125 */ 126 static struct percpu *bpf_gstats_percpu; /* struct bpf_stat */ 127 128 #define BPF_STATINC(id) \ 129 { \ 130 struct bpf_stat *__stats = \ 131 percpu_getref(bpf_gstats_percpu); \ 132 __stats->bs_##id++; \ 133 percpu_putref(bpf_gstats_percpu); \ 134 } 135 136 /* 137 * Locking notes: 138 * - bpf_mtx (adaptive mutex) protects: 139 * - Gobal lists: bpf_iflist and bpf_dlist 140 * - struct bpf_if 141 * - bpf_close 142 * - bpf_psz (pserialize) 143 * - struct bpf_d has two mutexes: 144 * - bd_buf_mtx (spin mutex) protects the buffers that can be accessed 145 * on packet tapping 146 * - bd_mtx (adaptive mutex) protects member variables other than the buffers 147 * - Locking order: bpf_mtx => bpf_d#bd_mtx => bpf_d#bd_buf_mtx 148 * - struct bpf_d obtained via fp->f_bpf in bpf_read and bpf_write is 149 * never freed because struct bpf_d is only freed in bpf_close and 150 * bpf_close never be called while executing bpf_read and bpf_write 151 * - A filter that is assigned to bpf_d can be replaced with another filter 152 * while tapping packets, so it needs to be done atomically 153 * - struct bpf_d is iterated on bpf_dlist with psz 154 * - struct bpf_if is iterated on bpf_iflist with psz or psref 155 */ 156 /* 157 * Use a mutex to avoid a race condition between gathering the stats/peers 158 * and opening/closing the device. 159 */ 160 static kmutex_t bpf_mtx; 161 162 static struct psref_class *bpf_psref_class __read_mostly; 163 static pserialize_t bpf_psz; 164 165 static inline void 166 bpf_if_acquire(struct bpf_if *bp, struct psref *psref) 167 { 168 169 psref_acquire(psref, &bp->bif_psref, bpf_psref_class); 170 } 171 172 static inline void 173 bpf_if_release(struct bpf_if *bp, struct psref *psref) 174 { 175 176 psref_release(psref, &bp->bif_psref, bpf_psref_class); 177 } 178 179 /* 180 * bpf_iflist is the list of interfaces; each corresponds to an ifnet 181 * bpf_dtab holds the descriptors, indexed by minor device # 182 */ 183 static struct pslist_head bpf_iflist; 184 static struct pslist_head bpf_dlist; 185 186 /* Macros for bpf_d on bpf_dlist */ 187 #define BPF_DLIST_WRITER_INSERT_HEAD(__d) \ 188 PSLIST_WRITER_INSERT_HEAD(&bpf_dlist, (__d), bd_bpf_dlist_entry) 189 #define BPF_DLIST_READER_FOREACH(__d) \ 190 PSLIST_READER_FOREACH((__d), &bpf_dlist, struct bpf_d, \ 191 bd_bpf_dlist_entry) 192 #define BPF_DLIST_WRITER_FOREACH(__d) \ 193 PSLIST_WRITER_FOREACH((__d), &bpf_dlist, struct bpf_d, \ 194 bd_bpf_dlist_entry) 195 #define BPF_DLIST_ENTRY_INIT(__d) \ 196 PSLIST_ENTRY_INIT((__d), bd_bpf_dlist_entry) 197 #define BPF_DLIST_WRITER_REMOVE(__d) \ 198 PSLIST_WRITER_REMOVE((__d), bd_bpf_dlist_entry) 199 #define BPF_DLIST_ENTRY_DESTROY(__d) \ 200 PSLIST_ENTRY_DESTROY((__d), bd_bpf_dlist_entry) 201 202 /* Macros for bpf_if on bpf_iflist */ 203 #define BPF_IFLIST_WRITER_INSERT_HEAD(__bp) \ 204 PSLIST_WRITER_INSERT_HEAD(&bpf_iflist, (__bp), bif_iflist_entry) 205 #define BPF_IFLIST_READER_FOREACH(__bp) \ 206 PSLIST_READER_FOREACH((__bp), &bpf_iflist, struct bpf_if, \ 207 bif_iflist_entry) 208 #define BPF_IFLIST_WRITER_FOREACH(__bp) \ 209 PSLIST_WRITER_FOREACH((__bp), &bpf_iflist, struct bpf_if, \ 210 bif_iflist_entry) 211 #define BPF_IFLIST_WRITER_REMOVE(__bp) \ 212 PSLIST_WRITER_REMOVE((__bp), bif_iflist_entry) 213 #define BPF_IFLIST_ENTRY_INIT(__bp) \ 214 PSLIST_ENTRY_INIT((__bp), bif_iflist_entry) 215 #define BPF_IFLIST_ENTRY_DESTROY(__bp) \ 216 PSLIST_ENTRY_DESTROY((__bp), bif_iflist_entry) 217 218 /* Macros for bpf_d on bpf_if#bif_dlist_pslist */ 219 #define BPFIF_DLIST_READER_FOREACH(__d, __bp) \ 220 PSLIST_READER_FOREACH((__d), &(__bp)->bif_dlist_head, struct bpf_d, \ 221 bd_bif_dlist_entry) 222 #define BPFIF_DLIST_WRITER_INSERT_HEAD(__bp, __d) \ 223 PSLIST_WRITER_INSERT_HEAD(&(__bp)->bif_dlist_head, (__d), \ 224 bd_bif_dlist_entry) 225 #define BPFIF_DLIST_WRITER_REMOVE(__d) \ 226 PSLIST_WRITER_REMOVE((__d), bd_bif_dlist_entry) 227 #define BPFIF_DLIST_ENTRY_INIT(__d) \ 228 PSLIST_ENTRY_INIT((__d), bd_bif_dlist_entry) 229 #define BPFIF_DLIST_READER_EMPTY(__bp) \ 230 (PSLIST_READER_FIRST(&(__bp)->bif_dlist_head, struct bpf_d, \ 231 bd_bif_dlist_entry) == NULL) 232 #define BPFIF_DLIST_WRITER_EMPTY(__bp) \ 233 (PSLIST_WRITER_FIRST(&(__bp)->bif_dlist_head, struct bpf_d, \ 234 bd_bif_dlist_entry) == NULL) 235 #define BPFIF_DLIST_ENTRY_DESTROY(__d) \ 236 PSLIST_ENTRY_DESTROY((__d), bd_bif_dlist_entry) 237 238 static int bpf_allocbufs(struct bpf_d *); 239 static void bpf_deliver(struct bpf_if *, 240 void *(*cpfn)(void *, const void *, size_t), 241 void *, u_int, u_int, const bool); 242 static void bpf_freed(struct bpf_d *); 243 static void bpf_free_filter(struct bpf_filter *); 244 static void bpf_ifname(struct ifnet *, struct ifreq *); 245 static void *bpf_mcpy(void *, const void *, size_t); 246 static int bpf_movein(struct uio *, int, uint64_t, 247 struct mbuf **, struct sockaddr *); 248 static void bpf_attachd(struct bpf_d *, struct bpf_if *); 249 static void bpf_detachd(struct bpf_d *); 250 static int bpf_setif(struct bpf_d *, struct ifreq *); 251 static int bpf_setf(struct bpf_d *, struct bpf_program *); 252 static void bpf_timed_out(void *); 253 static inline void 254 bpf_wakeup(struct bpf_d *); 255 static int bpf_hdrlen(struct bpf_d *); 256 static void catchpacket(struct bpf_d *, u_char *, u_int, u_int, 257 void *(*)(void *, const void *, size_t), struct timespec *); 258 static void reset_d(struct bpf_d *); 259 static int bpf_getdltlist(struct bpf_d *, struct bpf_dltlist *); 260 static int bpf_setdlt(struct bpf_d *, u_int); 261 262 static int bpf_read(struct file *, off_t *, struct uio *, kauth_cred_t, 263 int); 264 static int bpf_write(struct file *, off_t *, struct uio *, kauth_cred_t, 265 int); 266 static int bpf_ioctl(struct file *, u_long, void *); 267 static int bpf_poll(struct file *, int); 268 static int bpf_stat(struct file *, struct stat *); 269 static int bpf_close(struct file *); 270 static int bpf_kqfilter(struct file *, struct knote *); 271 static void bpf_softintr(void *); 272 273 static const struct fileops bpf_fileops = { 274 .fo_read = bpf_read, 275 .fo_write = bpf_write, 276 .fo_ioctl = bpf_ioctl, 277 .fo_fcntl = fnullop_fcntl, 278 .fo_poll = bpf_poll, 279 .fo_stat = bpf_stat, 280 .fo_close = bpf_close, 281 .fo_kqfilter = bpf_kqfilter, 282 .fo_restart = fnullop_restart, 283 }; 284 285 dev_type_open(bpfopen); 286 287 const struct cdevsw bpf_cdevsw = { 288 .d_open = bpfopen, 289 .d_close = noclose, 290 .d_read = noread, 291 .d_write = nowrite, 292 .d_ioctl = noioctl, 293 .d_stop = nostop, 294 .d_tty = notty, 295 .d_poll = nopoll, 296 .d_mmap = nommap, 297 .d_kqfilter = nokqfilter, 298 .d_discard = nodiscard, 299 .d_flag = D_OTHER | D_MPSAFE 300 }; 301 302 bpfjit_func_t 303 bpf_jit_generate(bpf_ctx_t *bc, void *code, size_t size) 304 { 305 306 membar_consumer(); 307 if (bpfjit_module_ops.bj_generate_code != NULL) { 308 return bpfjit_module_ops.bj_generate_code(bc, code, size); 309 } 310 return NULL; 311 } 312 313 void 314 bpf_jit_freecode(bpfjit_func_t jcode) 315 { 316 KASSERT(bpfjit_module_ops.bj_free_code != NULL); 317 bpfjit_module_ops.bj_free_code(jcode); 318 } 319 320 static int 321 bpf_movein(struct uio *uio, int linktype, uint64_t mtu, struct mbuf **mp, 322 struct sockaddr *sockp) 323 { 324 struct mbuf *m; 325 int error; 326 size_t len; 327 size_t hlen; 328 size_t align; 329 330 /* 331 * Build a sockaddr based on the data link layer type. 332 * We do this at this level because the ethernet header 333 * is copied directly into the data field of the sockaddr. 334 * In the case of SLIP, there is no header and the packet 335 * is forwarded as is. 336 * Also, we are careful to leave room at the front of the mbuf 337 * for the link level header. 338 */ 339 switch (linktype) { 340 341 case DLT_SLIP: 342 sockp->sa_family = AF_INET; 343 hlen = 0; 344 align = 0; 345 break; 346 347 case DLT_PPP: 348 sockp->sa_family = AF_UNSPEC; 349 hlen = 0; 350 align = 0; 351 break; 352 353 case DLT_EN10MB: 354 sockp->sa_family = AF_UNSPEC; 355 /* XXX Would MAXLINKHDR be better? */ 356 /* 6(dst)+6(src)+2(type) */ 357 hlen = sizeof(struct ether_header); 358 align = 2; 359 break; 360 361 case DLT_ARCNET: 362 sockp->sa_family = AF_UNSPEC; 363 hlen = ARC_HDRLEN; 364 align = 5; 365 break; 366 367 case DLT_FDDI: 368 sockp->sa_family = AF_LINK; 369 /* XXX 4(FORMAC)+6(dst)+6(src) */ 370 hlen = 16; 371 align = 0; 372 break; 373 374 case DLT_ECONET: 375 sockp->sa_family = AF_UNSPEC; 376 hlen = 6; 377 align = 2; 378 break; 379 380 case DLT_NULL: 381 sockp->sa_family = AF_UNSPEC; 382 hlen = 0; 383 align = 0; 384 break; 385 386 default: 387 return (EIO); 388 } 389 390 len = uio->uio_resid; 391 /* 392 * If there aren't enough bytes for a link level header or the 393 * packet length exceeds the interface mtu, return an error. 394 */ 395 if (len - hlen > mtu) 396 return (EMSGSIZE); 397 398 /* 399 * XXX Avoid complicated buffer chaining --- 400 * bail if it won't fit in a single mbuf. 401 * (Take into account possible alignment bytes) 402 */ 403 if (len + align > MCLBYTES) 404 return (EIO); 405 406 m = m_gethdr(M_WAIT, MT_DATA); 407 m_reset_rcvif(m); 408 m->m_pkthdr.len = (int)(len - hlen); 409 if (len + align > MHLEN) { 410 m_clget(m, M_WAIT); 411 if ((m->m_flags & M_EXT) == 0) { 412 error = ENOBUFS; 413 goto bad; 414 } 415 } 416 417 /* Insure the data is properly aligned */ 418 if (align > 0) { 419 m->m_data += align; 420 m->m_len -= (int)align; 421 } 422 423 error = uiomove(mtod(m, void *), len, uio); 424 if (error) 425 goto bad; 426 if (hlen != 0) { 427 memcpy(sockp->sa_data, mtod(m, void *), hlen); 428 m->m_data += hlen; /* XXX */ 429 len -= hlen; 430 } 431 m->m_len = (int)len; 432 *mp = m; 433 return (0); 434 435 bad: 436 m_freem(m); 437 return (error); 438 } 439 440 /* 441 * Attach file to the bpf interface, i.e. make d listen on bp. 442 */ 443 static void 444 bpf_attachd(struct bpf_d *d, struct bpf_if *bp) 445 { 446 447 KASSERT(mutex_owned(&bpf_mtx)); 448 KASSERT(mutex_owned(d->bd_mtx)); 449 /* 450 * Point d at bp, and add d to the interface's list of listeners. 451 * Finally, point the driver's bpf cookie at the interface so 452 * it will divert packets to bpf. 453 */ 454 d->bd_bif = bp; 455 BPFIF_DLIST_WRITER_INSERT_HEAD(bp, d); 456 457 *bp->bif_driverp = bp; 458 } 459 460 /* 461 * Detach a file from its interface. 462 */ 463 static void 464 bpf_detachd(struct bpf_d *d) 465 { 466 struct bpf_if *bp; 467 468 KASSERT(mutex_owned(&bpf_mtx)); 469 KASSERT(mutex_owned(d->bd_mtx)); 470 471 bp = d->bd_bif; 472 /* 473 * Check if this descriptor had requested promiscuous mode. 474 * If so, turn it off. 475 */ 476 if (d->bd_promisc) { 477 int error __diagused; 478 479 d->bd_promisc = 0; 480 /* 481 * Take device out of promiscuous mode. Since we were 482 * able to enter promiscuous mode, we should be able 483 * to turn it off. But we can get an error if 484 * the interface was configured down, so only panic 485 * if we don't get an unexpected error. 486 */ 487 #ifndef NET_MPSAFE 488 KERNEL_LOCK(1, NULL); 489 #endif 490 error = ifpromisc(bp->bif_ifp, 0); 491 #ifndef NET_MPSAFE 492 KERNEL_UNLOCK_ONE(NULL); 493 #endif 494 #ifdef DIAGNOSTIC 495 if (error) 496 printf("%s: ifpromisc failed: %d", __func__, error); 497 #endif 498 } 499 500 /* Remove d from the interface's descriptor list. */ 501 BPFIF_DLIST_WRITER_REMOVE(d); 502 503 pserialize_perform(bpf_psz); 504 505 if (BPFIF_DLIST_WRITER_EMPTY(bp)) { 506 /* 507 * Let the driver know that there are no more listeners. 508 */ 509 *d->bd_bif->bif_driverp = NULL; 510 } 511 d->bd_bif = NULL; 512 } 513 514 static void 515 bpf_init(void) 516 { 517 518 mutex_init(&bpf_mtx, MUTEX_DEFAULT, IPL_NONE); 519 bpf_psz = pserialize_create(); 520 bpf_psref_class = psref_class_create("bpf", IPL_SOFTNET); 521 522 PSLIST_INIT(&bpf_iflist); 523 PSLIST_INIT(&bpf_dlist); 524 525 bpf_gstats_percpu = percpu_alloc(sizeof(struct bpf_stat)); 526 527 return; 528 } 529 530 /* 531 * bpfilterattach() is called at boot time. We don't need to do anything 532 * here, since any initialization will happen as part of module init code. 533 */ 534 /* ARGSUSED */ 535 void 536 bpfilterattach(int n) 537 { 538 539 } 540 541 /* 542 * Open ethernet device. Clones. 543 */ 544 /* ARGSUSED */ 545 int 546 bpfopen(dev_t dev, int flag, int mode, struct lwp *l) 547 { 548 struct bpf_d *d; 549 struct file *fp; 550 int error, fd; 551 552 /* falloc() will fill in the descriptor for us. */ 553 if ((error = fd_allocfile(&fp, &fd)) != 0) 554 return error; 555 556 d = kmem_zalloc(sizeof(*d), KM_SLEEP); 557 d->bd_bufsize = bpf_bufsize; 558 d->bd_seesent = 1; 559 d->bd_feedback = 0; 560 d->bd_pid = l->l_proc->p_pid; 561 #ifdef _LP64 562 if (curproc->p_flag & PK_32) 563 d->bd_compat32 = 1; 564 #endif 565 getnanotime(&d->bd_btime); 566 d->bd_atime = d->bd_mtime = d->bd_btime; 567 callout_init(&d->bd_callout, 0); 568 selinit(&d->bd_sel); 569 d->bd_sih = softint_establish(SOFTINT_CLOCK, bpf_softintr, d); 570 d->bd_jitcode = NULL; 571 d->bd_filter = NULL; 572 BPF_DLIST_ENTRY_INIT(d); 573 BPFIF_DLIST_ENTRY_INIT(d); 574 d->bd_mtx = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTNET); 575 d->bd_buf_mtx = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET); 576 cv_init(&d->bd_cv, "bpf"); 577 578 mutex_enter(&bpf_mtx); 579 BPF_DLIST_WRITER_INSERT_HEAD(d); 580 mutex_exit(&bpf_mtx); 581 582 return fd_clone(fp, fd, flag, &bpf_fileops, d); 583 } 584 585 /* 586 * Close the descriptor by detaching it from its interface, 587 * deallocating its buffers, and marking it free. 588 */ 589 /* ARGSUSED */ 590 static int 591 bpf_close(struct file *fp) 592 { 593 struct bpf_d *d; 594 595 mutex_enter(&bpf_mtx); 596 597 if ((d = fp->f_bpf) == NULL) { 598 mutex_exit(&bpf_mtx); 599 return 0; 600 } 601 602 /* 603 * Refresh the PID associated with this bpf file. 604 */ 605 d->bd_pid = curproc->p_pid; 606 607 mutex_enter(d->bd_mtx); 608 if (d->bd_state == BPF_WAITING) 609 callout_halt(&d->bd_callout, d->bd_mtx); 610 d->bd_state = BPF_IDLE; 611 if (d->bd_bif) 612 bpf_detachd(d); 613 mutex_exit(d->bd_mtx); 614 615 BPF_DLIST_WRITER_REMOVE(d); 616 617 pserialize_perform(bpf_psz); 618 mutex_exit(&bpf_mtx); 619 620 BPFIF_DLIST_ENTRY_DESTROY(d); 621 BPF_DLIST_ENTRY_DESTROY(d); 622 fp->f_bpf = NULL; 623 bpf_freed(d); 624 callout_destroy(&d->bd_callout); 625 seldestroy(&d->bd_sel); 626 softint_disestablish(d->bd_sih); 627 mutex_obj_free(d->bd_mtx); 628 mutex_obj_free(d->bd_buf_mtx); 629 cv_destroy(&d->bd_cv); 630 631 kmem_free(d, sizeof(*d)); 632 633 return (0); 634 } 635 636 /* 637 * Rotate the packet buffers in descriptor d. Move the store buffer 638 * into the hold slot, and the free buffer into the store slot. 639 * Zero the length of the new store buffer. 640 */ 641 #define ROTATE_BUFFERS(d) \ 642 (d)->bd_hbuf = (d)->bd_sbuf; \ 643 (d)->bd_hlen = (d)->bd_slen; \ 644 (d)->bd_sbuf = (d)->bd_fbuf; \ 645 (d)->bd_slen = 0; \ 646 (d)->bd_fbuf = NULL; 647 /* 648 * bpfread - read next chunk of packets from buffers 649 */ 650 static int 651 bpf_read(struct file *fp, off_t *offp, struct uio *uio, 652 kauth_cred_t cred, int flags) 653 { 654 struct bpf_d *d = fp->f_bpf; 655 int timed_out; 656 int error; 657 658 getnanotime(&d->bd_atime); 659 /* 660 * Restrict application to use a buffer the same size as 661 * the kernel buffers. 662 */ 663 if (uio->uio_resid != d->bd_bufsize) 664 return (EINVAL); 665 666 mutex_enter(d->bd_mtx); 667 if (d->bd_state == BPF_WAITING) 668 callout_halt(&d->bd_callout, d->bd_buf_mtx); 669 timed_out = (d->bd_state == BPF_TIMED_OUT); 670 d->bd_state = BPF_IDLE; 671 mutex_exit(d->bd_mtx); 672 /* 673 * If the hold buffer is empty, then do a timed sleep, which 674 * ends when the timeout expires or when enough packets 675 * have arrived to fill the store buffer. 676 */ 677 mutex_enter(d->bd_buf_mtx); 678 while (d->bd_hbuf == NULL) { 679 if (fp->f_flag & FNONBLOCK) { 680 if (d->bd_slen == 0) { 681 error = EWOULDBLOCK; 682 goto out; 683 } 684 ROTATE_BUFFERS(d); 685 break; 686 } 687 688 if ((d->bd_immediate || timed_out) && d->bd_slen != 0) { 689 /* 690 * A packet(s) either arrived since the previous 691 * read or arrived while we were asleep. 692 * Rotate the buffers and return what's here. 693 */ 694 ROTATE_BUFFERS(d); 695 break; 696 } 697 698 error = cv_timedwait_sig(&d->bd_cv, d->bd_buf_mtx, d->bd_rtout); 699 700 if (error == EINTR || error == ERESTART) 701 goto out; 702 703 if (error == EWOULDBLOCK) { 704 /* 705 * On a timeout, return what's in the buffer, 706 * which may be nothing. If there is something 707 * in the store buffer, we can rotate the buffers. 708 */ 709 if (d->bd_hbuf) 710 /* 711 * We filled up the buffer in between 712 * getting the timeout and arriving 713 * here, so we don't need to rotate. 714 */ 715 break; 716 717 if (d->bd_slen == 0) { 718 error = 0; 719 goto out; 720 } 721 ROTATE_BUFFERS(d); 722 break; 723 } 724 if (error != 0) 725 goto out; 726 } 727 /* 728 * At this point, we know we have something in the hold slot. 729 */ 730 mutex_exit(d->bd_buf_mtx); 731 732 /* 733 * Move data from hold buffer into user space. 734 * We know the entire buffer is transferred since 735 * we checked above that the read buffer is bpf_bufsize bytes. 736 */ 737 error = uiomove(d->bd_hbuf, d->bd_hlen, uio); 738 739 mutex_enter(d->bd_buf_mtx); 740 d->bd_fbuf = d->bd_hbuf; 741 d->bd_hbuf = NULL; 742 d->bd_hlen = 0; 743 out: 744 mutex_exit(d->bd_buf_mtx); 745 return (error); 746 } 747 748 749 /* 750 * If there are processes sleeping on this descriptor, wake them up. 751 */ 752 static inline void 753 bpf_wakeup(struct bpf_d *d) 754 { 755 756 mutex_enter(d->bd_buf_mtx); 757 cv_broadcast(&d->bd_cv); 758 mutex_exit(d->bd_buf_mtx); 759 760 if (d->bd_async) 761 softint_schedule(d->bd_sih); 762 selnotify(&d->bd_sel, 0, 0); 763 } 764 765 static void 766 bpf_softintr(void *cookie) 767 { 768 struct bpf_d *d; 769 770 d = cookie; 771 if (d->bd_async) 772 fownsignal(d->bd_pgid, SIGIO, 0, 0, NULL); 773 } 774 775 static void 776 bpf_timed_out(void *arg) 777 { 778 struct bpf_d *d = arg; 779 780 mutex_enter(d->bd_mtx); 781 if (d->bd_state == BPF_WAITING) { 782 d->bd_state = BPF_TIMED_OUT; 783 if (d->bd_slen != 0) 784 bpf_wakeup(d); 785 } 786 mutex_exit(d->bd_mtx); 787 } 788 789 790 static int 791 bpf_write(struct file *fp, off_t *offp, struct uio *uio, 792 kauth_cred_t cred, int flags) 793 { 794 struct bpf_d *d = fp->f_bpf; 795 struct bpf_if *bp; 796 struct ifnet *ifp; 797 struct mbuf *m, *mc; 798 int error; 799 static struct sockaddr_storage dst; 800 struct psref psref; 801 int bound; 802 803 m = NULL; /* XXX gcc */ 804 805 bound = curlwp_bind(); 806 mutex_enter(d->bd_mtx); 807 bp = d->bd_bif; 808 if (bp == NULL) { 809 mutex_exit(d->bd_mtx); 810 error = ENXIO; 811 goto out_bindx; 812 } 813 bpf_if_acquire(bp, &psref); 814 mutex_exit(d->bd_mtx); 815 816 getnanotime(&d->bd_mtime); 817 818 ifp = bp->bif_ifp; 819 if (if_is_deactivated(ifp)) { 820 error = ENXIO; 821 goto out; 822 } 823 824 if (uio->uio_resid == 0) { 825 error = 0; 826 goto out; 827 } 828 829 error = bpf_movein(uio, (int)bp->bif_dlt, ifp->if_mtu, &m, 830 (struct sockaddr *) &dst); 831 if (error) 832 goto out; 833 834 if (m->m_pkthdr.len > ifp->if_mtu) { 835 m_freem(m); 836 error = EMSGSIZE; 837 goto out; 838 } 839 840 if (d->bd_hdrcmplt) 841 dst.ss_family = pseudo_AF_HDRCMPLT; 842 843 if (d->bd_feedback) { 844 mc = m_dup(m, 0, M_COPYALL, M_NOWAIT); 845 if (mc != NULL) 846 m_set_rcvif(mc, ifp); 847 /* Set M_PROMISC for outgoing packets to be discarded. */ 848 if (1 /*d->bd_direction == BPF_D_INOUT*/) 849 m->m_flags |= M_PROMISC; 850 } else 851 mc = NULL; 852 853 error = if_output_lock(ifp, ifp, m, (struct sockaddr *) &dst, NULL); 854 855 if (mc != NULL) { 856 if (error == 0) 857 ifp->_if_input(ifp, mc); 858 else 859 m_freem(mc); 860 } 861 /* 862 * The driver frees the mbuf. 863 */ 864 out: 865 bpf_if_release(bp, &psref); 866 out_bindx: 867 curlwp_bindx(bound); 868 return error; 869 } 870 871 /* 872 * Reset a descriptor by flushing its packet buffer and clearing the 873 * receive and drop counts. 874 */ 875 static void 876 reset_d(struct bpf_d *d) 877 { 878 879 KASSERT(mutex_owned(d->bd_mtx)); 880 881 mutex_enter(d->bd_buf_mtx); 882 if (d->bd_hbuf) { 883 /* Free the hold buffer. */ 884 d->bd_fbuf = d->bd_hbuf; 885 d->bd_hbuf = NULL; 886 } 887 d->bd_slen = 0; 888 d->bd_hlen = 0; 889 d->bd_rcount = 0; 890 d->bd_dcount = 0; 891 d->bd_ccount = 0; 892 mutex_exit(d->bd_buf_mtx); 893 } 894 895 /* 896 * FIONREAD Check for read packet available. 897 * BIOCGBLEN Get buffer len [for read()]. 898 * BIOCSETF Set ethernet read filter. 899 * BIOCFLUSH Flush read packet buffer. 900 * BIOCPROMISC Put interface into promiscuous mode. 901 * BIOCGDLT Get link layer type. 902 * BIOCGETIF Get interface name. 903 * BIOCSETIF Set interface. 904 * BIOCSRTIMEOUT Set read timeout. 905 * BIOCGRTIMEOUT Get read timeout. 906 * BIOCGSTATS Get packet stats. 907 * BIOCIMMEDIATE Set immediate mode. 908 * BIOCVERSION Get filter language version. 909 * BIOCGHDRCMPLT Get "header already complete" flag. 910 * BIOCSHDRCMPLT Set "header already complete" flag. 911 * BIOCSFEEDBACK Set packet feedback mode. 912 * BIOCGFEEDBACK Get packet feedback mode. 913 * BIOCGSEESENT Get "see sent packets" mode. 914 * BIOCSSEESENT Set "see sent packets" mode. 915 */ 916 /* ARGSUSED */ 917 static int 918 bpf_ioctl(struct file *fp, u_long cmd, void *addr) 919 { 920 struct bpf_d *d = fp->f_bpf; 921 int error = 0; 922 923 /* 924 * Refresh the PID associated with this bpf file. 925 */ 926 d->bd_pid = curproc->p_pid; 927 #ifdef _LP64 928 if (curproc->p_flag & PK_32) 929 d->bd_compat32 = 1; 930 else 931 d->bd_compat32 = 0; 932 #endif 933 934 mutex_enter(d->bd_mtx); 935 if (d->bd_state == BPF_WAITING) 936 callout_halt(&d->bd_callout, d->bd_mtx); 937 d->bd_state = BPF_IDLE; 938 mutex_exit(d->bd_mtx); 939 940 switch (cmd) { 941 942 default: 943 error = EINVAL; 944 break; 945 946 /* 947 * Check for read packet available. 948 */ 949 case FIONREAD: 950 { 951 int n; 952 953 mutex_enter(d->bd_buf_mtx); 954 n = d->bd_slen; 955 if (d->bd_hbuf) 956 n += d->bd_hlen; 957 mutex_exit(d->bd_buf_mtx); 958 959 *(int *)addr = n; 960 break; 961 } 962 963 /* 964 * Get buffer len [for read()]. 965 */ 966 case BIOCGBLEN: 967 *(u_int *)addr = d->bd_bufsize; 968 break; 969 970 /* 971 * Set buffer length. 972 */ 973 case BIOCSBLEN: 974 /* 975 * Forbid to change the buffer length if buffers are already 976 * allocated. 977 */ 978 mutex_enter(d->bd_mtx); 979 mutex_enter(d->bd_buf_mtx); 980 if (d->bd_bif != NULL || d->bd_sbuf != NULL) 981 error = EINVAL; 982 else { 983 u_int size = *(u_int *)addr; 984 985 if (size > bpf_maxbufsize) 986 *(u_int *)addr = size = bpf_maxbufsize; 987 else if (size < BPF_MINBUFSIZE) 988 *(u_int *)addr = size = BPF_MINBUFSIZE; 989 d->bd_bufsize = size; 990 } 991 mutex_exit(d->bd_buf_mtx); 992 mutex_exit(d->bd_mtx); 993 break; 994 995 /* 996 * Set link layer read filter. 997 */ 998 case BIOCSETF: 999 error = bpf_setf(d, addr); 1000 break; 1001 1002 /* 1003 * Flush read packet buffer. 1004 */ 1005 case BIOCFLUSH: 1006 mutex_enter(d->bd_mtx); 1007 reset_d(d); 1008 mutex_exit(d->bd_mtx); 1009 break; 1010 1011 /* 1012 * Put interface into promiscuous mode. 1013 */ 1014 case BIOCPROMISC: 1015 mutex_enter(d->bd_mtx); 1016 if (d->bd_bif == NULL) { 1017 mutex_exit(d->bd_mtx); 1018 /* 1019 * No interface attached yet. 1020 */ 1021 error = EINVAL; 1022 break; 1023 } 1024 if (d->bd_promisc == 0) { 1025 #ifndef NET_MPSAFE 1026 KERNEL_LOCK(1, NULL); 1027 #endif 1028 error = ifpromisc(d->bd_bif->bif_ifp, 1); 1029 #ifndef NET_MPSAFE 1030 KERNEL_UNLOCK_ONE(NULL); 1031 #endif 1032 if (error == 0) 1033 d->bd_promisc = 1; 1034 } 1035 mutex_exit(d->bd_mtx); 1036 break; 1037 1038 /* 1039 * Get device parameters. 1040 */ 1041 case BIOCGDLT: 1042 mutex_enter(d->bd_mtx); 1043 if (d->bd_bif == NULL) 1044 error = EINVAL; 1045 else 1046 *(u_int *)addr = d->bd_bif->bif_dlt; 1047 mutex_exit(d->bd_mtx); 1048 break; 1049 1050 /* 1051 * Get a list of supported device parameters. 1052 */ 1053 case BIOCGDLTLIST: 1054 mutex_enter(d->bd_mtx); 1055 if (d->bd_bif == NULL) 1056 error = EINVAL; 1057 else 1058 error = bpf_getdltlist(d, addr); 1059 mutex_exit(d->bd_mtx); 1060 break; 1061 1062 /* 1063 * Set device parameters. 1064 */ 1065 case BIOCSDLT: 1066 mutex_enter(&bpf_mtx); 1067 mutex_enter(d->bd_mtx); 1068 if (d->bd_bif == NULL) 1069 error = EINVAL; 1070 else 1071 error = bpf_setdlt(d, *(u_int *)addr); 1072 mutex_exit(d->bd_mtx); 1073 mutex_exit(&bpf_mtx); 1074 break; 1075 1076 /* 1077 * Set interface name. 1078 */ 1079 #ifdef OBIOCGETIF 1080 case OBIOCGETIF: 1081 #endif 1082 case BIOCGETIF: 1083 mutex_enter(d->bd_mtx); 1084 if (d->bd_bif == NULL) 1085 error = EINVAL; 1086 else 1087 bpf_ifname(d->bd_bif->bif_ifp, addr); 1088 mutex_exit(d->bd_mtx); 1089 break; 1090 1091 /* 1092 * Set interface. 1093 */ 1094 #ifdef OBIOCSETIF 1095 case OBIOCSETIF: 1096 #endif 1097 case BIOCSETIF: 1098 mutex_enter(&bpf_mtx); 1099 error = bpf_setif(d, addr); 1100 mutex_exit(&bpf_mtx); 1101 break; 1102 1103 /* 1104 * Set read timeout. 1105 */ 1106 case BIOCSRTIMEOUT: 1107 { 1108 struct timeval *tv = addr; 1109 1110 /* Compute number of ticks. */ 1111 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 1112 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 1113 d->bd_rtout = 1; 1114 break; 1115 } 1116 1117 #ifdef BIOCGORTIMEOUT 1118 /* 1119 * Get read timeout. 1120 */ 1121 case BIOCGORTIMEOUT: 1122 { 1123 struct timeval50 *tv = addr; 1124 1125 tv->tv_sec = d->bd_rtout / hz; 1126 tv->tv_usec = (d->bd_rtout % hz) * tick; 1127 break; 1128 } 1129 #endif 1130 1131 #ifdef BIOCSORTIMEOUT 1132 /* 1133 * Set read timeout. 1134 */ 1135 case BIOCSORTIMEOUT: 1136 { 1137 struct timeval50 *tv = addr; 1138 1139 /* Compute number of ticks. */ 1140 d->bd_rtout = tv->tv_sec * hz + tv->tv_usec / tick; 1141 if ((d->bd_rtout == 0) && (tv->tv_usec != 0)) 1142 d->bd_rtout = 1; 1143 break; 1144 } 1145 #endif 1146 1147 /* 1148 * Get read timeout. 1149 */ 1150 case BIOCGRTIMEOUT: 1151 { 1152 struct timeval *tv = addr; 1153 1154 tv->tv_sec = d->bd_rtout / hz; 1155 tv->tv_usec = (d->bd_rtout % hz) * tick; 1156 break; 1157 } 1158 /* 1159 * Get packet stats. 1160 */ 1161 case BIOCGSTATS: 1162 { 1163 struct bpf_stat *bs = addr; 1164 1165 bs->bs_recv = d->bd_rcount; 1166 bs->bs_drop = d->bd_dcount; 1167 bs->bs_capt = d->bd_ccount; 1168 break; 1169 } 1170 1171 case BIOCGSTATSOLD: 1172 { 1173 struct bpf_stat_old *bs = addr; 1174 1175 bs->bs_recv = d->bd_rcount; 1176 bs->bs_drop = d->bd_dcount; 1177 break; 1178 } 1179 1180 /* 1181 * Set immediate mode. 1182 */ 1183 case BIOCIMMEDIATE: 1184 d->bd_immediate = *(u_int *)addr; 1185 break; 1186 1187 case BIOCVERSION: 1188 { 1189 struct bpf_version *bv = addr; 1190 1191 bv->bv_major = BPF_MAJOR_VERSION; 1192 bv->bv_minor = BPF_MINOR_VERSION; 1193 break; 1194 } 1195 1196 case BIOCGHDRCMPLT: /* get "header already complete" flag */ 1197 *(u_int *)addr = d->bd_hdrcmplt; 1198 break; 1199 1200 case BIOCSHDRCMPLT: /* set "header already complete" flag */ 1201 d->bd_hdrcmplt = *(u_int *)addr ? 1 : 0; 1202 break; 1203 1204 /* 1205 * Get "see sent packets" flag 1206 */ 1207 case BIOCGSEESENT: 1208 *(u_int *)addr = d->bd_seesent; 1209 break; 1210 1211 /* 1212 * Set "see sent" packets flag 1213 */ 1214 case BIOCSSEESENT: 1215 d->bd_seesent = *(u_int *)addr; 1216 break; 1217 1218 /* 1219 * Set "feed packets from bpf back to input" mode 1220 */ 1221 case BIOCSFEEDBACK: 1222 d->bd_feedback = *(u_int *)addr; 1223 break; 1224 1225 /* 1226 * Get "feed packets from bpf back to input" mode 1227 */ 1228 case BIOCGFEEDBACK: 1229 *(u_int *)addr = d->bd_feedback; 1230 break; 1231 1232 case FIONBIO: /* Non-blocking I/O */ 1233 /* 1234 * No need to do anything special as we use IO_NDELAY in 1235 * bpfread() as an indication of whether or not to block 1236 * the read. 1237 */ 1238 break; 1239 1240 case FIOASYNC: /* Send signal on receive packets */ 1241 d->bd_async = *(int *)addr; 1242 break; 1243 1244 case TIOCSPGRP: /* Process or group to send signals to */ 1245 case FIOSETOWN: 1246 error = fsetown(&d->bd_pgid, cmd, addr); 1247 break; 1248 1249 case TIOCGPGRP: 1250 case FIOGETOWN: 1251 error = fgetown(d->bd_pgid, cmd, addr); 1252 break; 1253 } 1254 return (error); 1255 } 1256 1257 /* 1258 * Set d's packet filter program to fp. If this file already has a filter, 1259 * free it and replace it. Returns EINVAL for bogus requests. 1260 */ 1261 static int 1262 bpf_setf(struct bpf_d *d, struct bpf_program *fp) 1263 { 1264 struct bpf_insn *fcode; 1265 bpfjit_func_t jcode; 1266 size_t flen, size = 0; 1267 struct bpf_filter *oldf, *newf; 1268 1269 jcode = NULL; 1270 flen = fp->bf_len; 1271 1272 if ((fp->bf_insns == NULL && flen) || flen > BPF_MAXINSNS) { 1273 return EINVAL; 1274 } 1275 1276 if (flen) { 1277 /* 1278 * Allocate the buffer, copy the byte-code from 1279 * userspace and validate it. 1280 */ 1281 size = flen * sizeof(*fp->bf_insns); 1282 fcode = kmem_alloc(size, KM_SLEEP); 1283 if (copyin(fp->bf_insns, fcode, size) != 0 || 1284 !bpf_validate(fcode, (int)flen)) { 1285 kmem_free(fcode, size); 1286 return EINVAL; 1287 } 1288 membar_consumer(); 1289 if (bpf_jit) 1290 jcode = bpf_jit_generate(NULL, fcode, flen); 1291 } else { 1292 fcode = NULL; 1293 } 1294 1295 newf = kmem_alloc(sizeof(*newf), KM_SLEEP); 1296 newf->bf_insn = fcode; 1297 newf->bf_size = size; 1298 newf->bf_jitcode = jcode; 1299 d->bd_jitcode = jcode; /* XXX just for kvm(3) users */ 1300 1301 /* Need to hold bpf_mtx for pserialize_perform */ 1302 mutex_enter(&bpf_mtx); 1303 mutex_enter(d->bd_mtx); 1304 oldf = d->bd_filter; 1305 d->bd_filter = newf; 1306 membar_producer(); 1307 reset_d(d); 1308 pserialize_perform(bpf_psz); 1309 mutex_exit(d->bd_mtx); 1310 mutex_exit(&bpf_mtx); 1311 1312 if (oldf != NULL) 1313 bpf_free_filter(oldf); 1314 1315 return 0; 1316 } 1317 1318 /* 1319 * Detach a file from its current interface (if attached at all) and attach 1320 * to the interface indicated by the name stored in ifr. 1321 * Return an errno or 0. 1322 */ 1323 static int 1324 bpf_setif(struct bpf_d *d, struct ifreq *ifr) 1325 { 1326 struct bpf_if *bp; 1327 char *cp; 1328 int unit_seen, i, error; 1329 1330 KASSERT(mutex_owned(&bpf_mtx)); 1331 /* 1332 * Make sure the provided name has a unit number, and default 1333 * it to '0' if not specified. 1334 * XXX This is ugly ... do this differently? 1335 */ 1336 unit_seen = 0; 1337 cp = ifr->ifr_name; 1338 cp[sizeof(ifr->ifr_name) - 1] = '\0'; /* sanity */ 1339 while (*cp++) 1340 if (*cp >= '0' && *cp <= '9') 1341 unit_seen = 1; 1342 if (!unit_seen) { 1343 /* Make sure to leave room for the '\0'. */ 1344 for (i = 0; i < (IFNAMSIZ - 1); ++i) { 1345 if ((ifr->ifr_name[i] >= 'a' && 1346 ifr->ifr_name[i] <= 'z') || 1347 (ifr->ifr_name[i] >= 'A' && 1348 ifr->ifr_name[i] <= 'Z')) 1349 continue; 1350 ifr->ifr_name[i] = '0'; 1351 } 1352 } 1353 1354 /* 1355 * Look through attached interfaces for the named one. 1356 */ 1357 BPF_IFLIST_WRITER_FOREACH(bp) { 1358 struct ifnet *ifp = bp->bif_ifp; 1359 1360 if (ifp == NULL || 1361 strcmp(ifp->if_xname, ifr->ifr_name) != 0) 1362 continue; 1363 /* skip additional entry */ 1364 if (bp->bif_driverp != &ifp->if_bpf) 1365 continue; 1366 /* 1367 * We found the requested interface. 1368 * Allocate the packet buffers if we need to. 1369 * If we're already attached to requested interface, 1370 * just flush the buffer. 1371 */ 1372 /* 1373 * bpf_allocbufs is called only here. bpf_mtx ensures that 1374 * no race condition happen on d->bd_sbuf. 1375 */ 1376 if (d->bd_sbuf == NULL) { 1377 error = bpf_allocbufs(d); 1378 if (error != 0) 1379 return (error); 1380 } 1381 mutex_enter(d->bd_mtx); 1382 if (bp != d->bd_bif) { 1383 if (d->bd_bif) { 1384 /* 1385 * Detach if attached to something else. 1386 */ 1387 bpf_detachd(d); 1388 BPFIF_DLIST_ENTRY_INIT(d); 1389 } 1390 1391 bpf_attachd(d, bp); 1392 } 1393 reset_d(d); 1394 mutex_exit(d->bd_mtx); 1395 return (0); 1396 } 1397 /* Not found. */ 1398 return (ENXIO); 1399 } 1400 1401 /* 1402 * Copy the interface name to the ifreq. 1403 */ 1404 static void 1405 bpf_ifname(struct ifnet *ifp, struct ifreq *ifr) 1406 { 1407 memcpy(ifr->ifr_name, ifp->if_xname, IFNAMSIZ); 1408 } 1409 1410 static int 1411 bpf_stat(struct file *fp, struct stat *st) 1412 { 1413 struct bpf_d *d = fp->f_bpf; 1414 1415 (void)memset(st, 0, sizeof(*st)); 1416 mutex_enter(d->bd_mtx); 1417 st->st_dev = makedev(cdevsw_lookup_major(&bpf_cdevsw), d->bd_pid); 1418 st->st_atimespec = d->bd_atime; 1419 st->st_mtimespec = d->bd_mtime; 1420 st->st_ctimespec = st->st_birthtimespec = d->bd_btime; 1421 st->st_uid = kauth_cred_geteuid(fp->f_cred); 1422 st->st_gid = kauth_cred_getegid(fp->f_cred); 1423 st->st_mode = S_IFCHR; 1424 mutex_exit(d->bd_mtx); 1425 return 0; 1426 } 1427 1428 /* 1429 * Support for poll() system call 1430 * 1431 * Return true iff the specific operation will not block indefinitely - with 1432 * the assumption that it is safe to positively acknowledge a request for the 1433 * ability to write to the BPF device. 1434 * Otherwise, return false but make a note that a selnotify() must be done. 1435 */ 1436 static int 1437 bpf_poll(struct file *fp, int events) 1438 { 1439 struct bpf_d *d = fp->f_bpf; 1440 int revents; 1441 1442 /* 1443 * Refresh the PID associated with this bpf file. 1444 */ 1445 mutex_enter(&bpf_mtx); 1446 d->bd_pid = curproc->p_pid; 1447 1448 revents = events & (POLLOUT | POLLWRNORM); 1449 if (events & (POLLIN | POLLRDNORM)) { 1450 /* 1451 * An imitation of the FIONREAD ioctl code. 1452 */ 1453 mutex_enter(d->bd_mtx); 1454 if (d->bd_hlen != 0 || 1455 ((d->bd_immediate || d->bd_state == BPF_TIMED_OUT) && 1456 d->bd_slen != 0)) { 1457 revents |= events & (POLLIN | POLLRDNORM); 1458 } else { 1459 selrecord(curlwp, &d->bd_sel); 1460 /* Start the read timeout if necessary */ 1461 if (d->bd_rtout > 0 && d->bd_state == BPF_IDLE) { 1462 callout_reset(&d->bd_callout, d->bd_rtout, 1463 bpf_timed_out, d); 1464 d->bd_state = BPF_WAITING; 1465 } 1466 } 1467 mutex_exit(d->bd_mtx); 1468 } 1469 1470 mutex_exit(&bpf_mtx); 1471 return (revents); 1472 } 1473 1474 static void 1475 filt_bpfrdetach(struct knote *kn) 1476 { 1477 struct bpf_d *d = kn->kn_hook; 1478 1479 mutex_enter(d->bd_buf_mtx); 1480 SLIST_REMOVE(&d->bd_sel.sel_klist, kn, knote, kn_selnext); 1481 mutex_exit(d->bd_buf_mtx); 1482 } 1483 1484 static int 1485 filt_bpfread(struct knote *kn, long hint) 1486 { 1487 struct bpf_d *d = kn->kn_hook; 1488 int rv; 1489 1490 mutex_enter(d->bd_buf_mtx); 1491 kn->kn_data = d->bd_hlen; 1492 if (d->bd_immediate) 1493 kn->kn_data += d->bd_slen; 1494 rv = (kn->kn_data > 0); 1495 mutex_exit(d->bd_buf_mtx); 1496 return rv; 1497 } 1498 1499 static const struct filterops bpfread_filtops = { 1500 .f_isfd = 1, 1501 .f_attach = NULL, 1502 .f_detach = filt_bpfrdetach, 1503 .f_event = filt_bpfread, 1504 }; 1505 1506 static int 1507 bpf_kqfilter(struct file *fp, struct knote *kn) 1508 { 1509 struct bpf_d *d = fp->f_bpf; 1510 struct klist *klist; 1511 1512 mutex_enter(d->bd_buf_mtx); 1513 switch (kn->kn_filter) { 1514 case EVFILT_READ: 1515 klist = &d->bd_sel.sel_klist; 1516 kn->kn_fop = &bpfread_filtops; 1517 break; 1518 1519 default: 1520 mutex_exit(d->bd_buf_mtx); 1521 return (EINVAL); 1522 } 1523 1524 kn->kn_hook = d; 1525 1526 SLIST_INSERT_HEAD(klist, kn, kn_selnext); 1527 mutex_exit(d->bd_buf_mtx); 1528 1529 return (0); 1530 } 1531 1532 /* 1533 * Copy data from an mbuf chain into a buffer. This code is derived 1534 * from m_copydata in sys/uipc_mbuf.c. 1535 */ 1536 static void * 1537 bpf_mcpy(void *dst_arg, const void *src_arg, size_t len) 1538 { 1539 const struct mbuf *m; 1540 u_int count; 1541 u_char *dst; 1542 1543 m = src_arg; 1544 dst = dst_arg; 1545 while (len > 0) { 1546 if (m == NULL) 1547 panic("bpf_mcpy"); 1548 count = min(m->m_len, len); 1549 memcpy(dst, mtod(m, const void *), count); 1550 m = m->m_next; 1551 dst += count; 1552 len -= count; 1553 } 1554 return dst_arg; 1555 } 1556 1557 /* 1558 * Dispatch a packet to all the listeners on interface bp. 1559 * 1560 * pkt pointer to the packet, either a data buffer or an mbuf chain 1561 * buflen buffer length, if pkt is a data buffer 1562 * cpfn a function that can copy pkt into the listener's buffer 1563 * pktlen length of the packet 1564 * rcv true if packet came in 1565 */ 1566 static inline void 1567 bpf_deliver(struct bpf_if *bp, void *(*cpfn)(void *, const void *, size_t), 1568 void *pkt, u_int pktlen, u_int buflen, const bool rcv) 1569 { 1570 uint32_t mem[BPF_MEMWORDS]; 1571 bpf_args_t args = { 1572 .pkt = (const uint8_t *)pkt, 1573 .wirelen = pktlen, 1574 .buflen = buflen, 1575 .mem = mem, 1576 .arg = NULL 1577 }; 1578 bool gottime = false; 1579 struct timespec ts; 1580 struct bpf_d *d; 1581 int s; 1582 1583 KASSERT(!cpu_intr_p()); 1584 1585 /* 1586 * Note that the IPL does not have to be raised at this point. 1587 * The only problem that could arise here is that if two different 1588 * interfaces shared any data. This is not the case. 1589 */ 1590 s = pserialize_read_enter(); 1591 BPFIF_DLIST_READER_FOREACH(d, bp) { 1592 u_int slen = 0; 1593 struct bpf_filter *filter; 1594 1595 if (!d->bd_seesent && !rcv) { 1596 continue; 1597 } 1598 atomic_inc_ulong(&d->bd_rcount); 1599 BPF_STATINC(recv); 1600 1601 filter = d->bd_filter; 1602 membar_datadep_consumer(); 1603 if (filter != NULL) { 1604 if (filter->bf_jitcode != NULL) 1605 slen = filter->bf_jitcode(NULL, &args); 1606 else 1607 slen = bpf_filter_ext(NULL, filter->bf_insn, 1608 &args); 1609 } 1610 1611 if (!slen) { 1612 continue; 1613 } 1614 if (!gottime) { 1615 gottime = true; 1616 nanotime(&ts); 1617 } 1618 /* Assume catchpacket doesn't sleep */ 1619 catchpacket(d, pkt, pktlen, slen, cpfn, &ts); 1620 } 1621 pserialize_read_exit(s); 1622 } 1623 1624 /* 1625 * Incoming linkage from device drivers. Process the packet pkt, of length 1626 * pktlen, which is stored in a contiguous buffer. The packet is parsed 1627 * by each process' filter, and if accepted, stashed into the corresponding 1628 * buffer. 1629 */ 1630 static void 1631 _bpf_tap(struct bpf_if *bp, u_char *pkt, u_int pktlen) 1632 { 1633 1634 bpf_deliver(bp, memcpy, pkt, pktlen, pktlen, true); 1635 } 1636 1637 /* 1638 * Incoming linkage from device drivers, when the head of the packet is in 1639 * a buffer, and the tail is in an mbuf chain. 1640 */ 1641 static void 1642 _bpf_mtap2(struct bpf_if *bp, void *data, u_int dlen, struct mbuf *m) 1643 { 1644 u_int pktlen; 1645 struct mbuf mb; 1646 1647 /* Skip outgoing duplicate packets. */ 1648 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif_index == 0) { 1649 m->m_flags &= ~M_PROMISC; 1650 return; 1651 } 1652 1653 pktlen = m_length(m) + dlen; 1654 1655 /* 1656 * Craft on-stack mbuf suitable for passing to bpf_filter. 1657 * Note that we cut corners here; we only setup what's 1658 * absolutely needed--this mbuf should never go anywhere else. 1659 */ 1660 (void)memset(&mb, 0, sizeof(mb)); 1661 mb.m_next = m; 1662 mb.m_data = data; 1663 mb.m_len = dlen; 1664 1665 bpf_deliver(bp, bpf_mcpy, &mb, pktlen, 0, m->m_pkthdr.rcvif_index != 0); 1666 } 1667 1668 /* 1669 * Incoming linkage from device drivers, when packet is in an mbuf chain. 1670 */ 1671 static void 1672 _bpf_mtap(struct bpf_if *bp, struct mbuf *m) 1673 { 1674 void *(*cpfn)(void *, const void *, size_t); 1675 u_int pktlen, buflen; 1676 void *marg; 1677 1678 /* Skip outgoing duplicate packets. */ 1679 if ((m->m_flags & M_PROMISC) != 0 && m->m_pkthdr.rcvif_index == 0) { 1680 m->m_flags &= ~M_PROMISC; 1681 return; 1682 } 1683 1684 pktlen = m_length(m); 1685 1686 if (pktlen == m->m_len) { 1687 cpfn = (void *)memcpy; 1688 marg = mtod(m, void *); 1689 buflen = pktlen; 1690 } else { 1691 cpfn = bpf_mcpy; 1692 marg = m; 1693 buflen = 0; 1694 } 1695 1696 bpf_deliver(bp, cpfn, marg, pktlen, buflen, m->m_pkthdr.rcvif_index != 0); 1697 } 1698 1699 /* 1700 * We need to prepend the address family as 1701 * a four byte field. Cons up a dummy header 1702 * to pacify bpf. This is safe because bpf 1703 * will only read from the mbuf (i.e., it won't 1704 * try to free it or keep a pointer a to it). 1705 */ 1706 static void 1707 _bpf_mtap_af(struct bpf_if *bp, uint32_t af, struct mbuf *m) 1708 { 1709 struct mbuf m0; 1710 1711 m0.m_flags = 0; 1712 m0.m_next = m; 1713 m0.m_len = 4; 1714 m0.m_data = (char *)⁡ 1715 1716 _bpf_mtap(bp, &m0); 1717 } 1718 1719 /* 1720 * Put the SLIP pseudo-"link header" in place. 1721 * Note this M_PREPEND() should never fail, 1722 * swince we know we always have enough space 1723 * in the input buffer. 1724 */ 1725 static void 1726 _bpf_mtap_sl_in(struct bpf_if *bp, u_char *chdr, struct mbuf **m) 1727 { 1728 u_char *hp; 1729 1730 M_PREPEND(*m, SLIP_HDRLEN, M_DONTWAIT); 1731 if (*m == NULL) 1732 return; 1733 1734 hp = mtod(*m, u_char *); 1735 hp[SLX_DIR] = SLIPDIR_IN; 1736 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1737 1738 _bpf_mtap(bp, *m); 1739 1740 m_adj(*m, SLIP_HDRLEN); 1741 } 1742 1743 /* 1744 * Put the SLIP pseudo-"link header" in 1745 * place. The compressed header is now 1746 * at the beginning of the mbuf. 1747 */ 1748 static void 1749 _bpf_mtap_sl_out(struct bpf_if *bp, u_char *chdr, struct mbuf *m) 1750 { 1751 struct mbuf m0; 1752 u_char *hp; 1753 1754 m0.m_flags = 0; 1755 m0.m_next = m; 1756 m0.m_data = m0.m_dat; 1757 m0.m_len = SLIP_HDRLEN; 1758 1759 hp = mtod(&m0, u_char *); 1760 1761 hp[SLX_DIR] = SLIPDIR_OUT; 1762 (void)memcpy(&hp[SLX_CHDR], chdr, CHDR_LEN); 1763 1764 _bpf_mtap(bp, &m0); 1765 m_freem(m); 1766 } 1767 1768 static struct mbuf * 1769 bpf_mbuf_enqueue(struct bpf_if *bp, struct mbuf *m) 1770 { 1771 struct mbuf *dup; 1772 1773 dup = m_dup(m, 0, M_COPYALL, M_NOWAIT); 1774 if (dup == NULL) 1775 return NULL; 1776 1777 if (bp->bif_mbuf_tail != NULL) { 1778 bp->bif_mbuf_tail->m_nextpkt = dup; 1779 } else { 1780 bp->bif_mbuf_head = dup; 1781 } 1782 bp->bif_mbuf_tail = dup; 1783 #ifdef BPF_MTAP_SOFTINT_DEBUG 1784 log(LOG_DEBUG, "%s: enqueued mbuf=%p to %s\n", 1785 __func__, dup, bp->bif_ifp->if_xname); 1786 #endif 1787 1788 return dup; 1789 } 1790 1791 static struct mbuf * 1792 bpf_mbuf_dequeue(struct bpf_if *bp) 1793 { 1794 struct mbuf *m; 1795 int s; 1796 1797 /* XXX NOMPSAFE: assumed running on one CPU */ 1798 s = splnet(); 1799 m = bp->bif_mbuf_head; 1800 if (m != NULL) { 1801 bp->bif_mbuf_head = m->m_nextpkt; 1802 m->m_nextpkt = NULL; 1803 1804 if (bp->bif_mbuf_head == NULL) 1805 bp->bif_mbuf_tail = NULL; 1806 #ifdef BPF_MTAP_SOFTINT_DEBUG 1807 log(LOG_DEBUG, "%s: dequeued mbuf=%p from %s\n", 1808 __func__, m, bp->bif_ifp->if_xname); 1809 #endif 1810 } 1811 splx(s); 1812 1813 return m; 1814 } 1815 1816 static void 1817 bpf_mtap_si(void *arg) 1818 { 1819 struct bpf_if *bp = arg; 1820 struct mbuf *m; 1821 1822 while ((m = bpf_mbuf_dequeue(bp)) != NULL) { 1823 #ifdef BPF_MTAP_SOFTINT_DEBUG 1824 log(LOG_DEBUG, "%s: tapping mbuf=%p on %s\n", 1825 __func__, m, bp->bif_ifp->if_xname); 1826 #endif 1827 bpf_ops->bpf_mtap(bp, m); 1828 m_freem(m); 1829 } 1830 } 1831 1832 static void 1833 _bpf_mtap_softint(struct ifnet *ifp, struct mbuf *m) 1834 { 1835 struct bpf_if *bp = ifp->if_bpf; 1836 struct mbuf *dup; 1837 1838 KASSERT(cpu_intr_p()); 1839 1840 /* To avoid extra invocations of the softint */ 1841 if (BPFIF_DLIST_READER_EMPTY(bp)) 1842 return; 1843 KASSERT(bp->bif_si != NULL); 1844 1845 dup = bpf_mbuf_enqueue(bp, m); 1846 if (dup != NULL) 1847 softint_schedule(bp->bif_si); 1848 } 1849 1850 static int 1851 bpf_hdrlen(struct bpf_d *d) 1852 { 1853 int hdrlen = d->bd_bif->bif_hdrlen; 1854 /* 1855 * Compute the length of the bpf header. This is not necessarily 1856 * equal to SIZEOF_BPF_HDR because we want to insert spacing such 1857 * that the network layer header begins on a longword boundary (for 1858 * performance reasons and to alleviate alignment restrictions). 1859 */ 1860 #ifdef _LP64 1861 if (d->bd_compat32) 1862 return (BPF_WORDALIGN32(hdrlen + SIZEOF_BPF_HDR32) - hdrlen); 1863 else 1864 #endif 1865 return (BPF_WORDALIGN(hdrlen + SIZEOF_BPF_HDR) - hdrlen); 1866 } 1867 1868 /* 1869 * Move the packet data from interface memory (pkt) into the 1870 * store buffer. Call the wakeup functions if it's time to wakeup 1871 * a listener (buffer full), "cpfn" is the routine called to do the 1872 * actual data transfer. memcpy is passed in to copy contiguous chunks, 1873 * while bpf_mcpy is passed in to copy mbuf chains. In the latter case, 1874 * pkt is really an mbuf. 1875 */ 1876 static void 1877 catchpacket(struct bpf_d *d, u_char *pkt, u_int pktlen, u_int snaplen, 1878 void *(*cpfn)(void *, const void *, size_t), struct timespec *ts) 1879 { 1880 char *h; 1881 int totlen, curlen, caplen; 1882 int hdrlen = bpf_hdrlen(d); 1883 int do_wakeup = 0; 1884 1885 atomic_inc_ulong(&d->bd_ccount); 1886 BPF_STATINC(capt); 1887 /* 1888 * Figure out how many bytes to move. If the packet is 1889 * greater or equal to the snapshot length, transfer that 1890 * much. Otherwise, transfer the whole packet (unless 1891 * we hit the buffer size limit). 1892 */ 1893 totlen = hdrlen + min(snaplen, pktlen); 1894 if (totlen > d->bd_bufsize) 1895 totlen = d->bd_bufsize; 1896 /* 1897 * If we adjusted totlen to fit the bufsize, it could be that 1898 * totlen is smaller than hdrlen because of the link layer header. 1899 */ 1900 caplen = totlen - hdrlen; 1901 if (caplen < 0) 1902 caplen = 0; 1903 1904 mutex_enter(d->bd_buf_mtx); 1905 /* 1906 * Round up the end of the previous packet to the next longword. 1907 */ 1908 #ifdef _LP64 1909 if (d->bd_compat32) 1910 curlen = BPF_WORDALIGN32(d->bd_slen); 1911 else 1912 #endif 1913 curlen = BPF_WORDALIGN(d->bd_slen); 1914 if (curlen + totlen > d->bd_bufsize) { 1915 /* 1916 * This packet will overflow the storage buffer. 1917 * Rotate the buffers if we can, then wakeup any 1918 * pending reads. 1919 */ 1920 if (d->bd_fbuf == NULL) { 1921 mutex_exit(d->bd_buf_mtx); 1922 /* 1923 * We haven't completed the previous read yet, 1924 * so drop the packet. 1925 */ 1926 atomic_inc_ulong(&d->bd_dcount); 1927 BPF_STATINC(drop); 1928 return; 1929 } 1930 ROTATE_BUFFERS(d); 1931 do_wakeup = 1; 1932 curlen = 0; 1933 } else if (d->bd_immediate || d->bd_state == BPF_TIMED_OUT) { 1934 /* 1935 * Immediate mode is set, or the read timeout has 1936 * already expired during a select call. A packet 1937 * arrived, so the reader should be woken up. 1938 */ 1939 do_wakeup = 1; 1940 } 1941 1942 /* 1943 * Append the bpf header. 1944 */ 1945 h = (char *)d->bd_sbuf + curlen; 1946 #ifdef _LP64 1947 if (d->bd_compat32) { 1948 struct bpf_hdr32 *hp32; 1949 1950 hp32 = (struct bpf_hdr32 *)h; 1951 hp32->bh_tstamp.tv_sec = ts->tv_sec; 1952 hp32->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1953 hp32->bh_datalen = pktlen; 1954 hp32->bh_hdrlen = hdrlen; 1955 hp32->bh_caplen = caplen; 1956 } else 1957 #endif 1958 { 1959 struct bpf_hdr *hp; 1960 1961 hp = (struct bpf_hdr *)h; 1962 hp->bh_tstamp.tv_sec = ts->tv_sec; 1963 hp->bh_tstamp.tv_usec = ts->tv_nsec / 1000; 1964 hp->bh_datalen = pktlen; 1965 hp->bh_hdrlen = hdrlen; 1966 hp->bh_caplen = caplen; 1967 } 1968 1969 /* 1970 * Copy the packet data into the store buffer and update its length. 1971 */ 1972 (*cpfn)(h + hdrlen, pkt, caplen); 1973 d->bd_slen = curlen + totlen; 1974 mutex_exit(d->bd_buf_mtx); 1975 1976 /* 1977 * Call bpf_wakeup after bd_slen has been updated so that kevent(2) 1978 * will cause filt_bpfread() to be called with it adjusted. 1979 */ 1980 if (do_wakeup) 1981 bpf_wakeup(d); 1982 } 1983 1984 /* 1985 * Initialize all nonzero fields of a descriptor. 1986 */ 1987 static int 1988 bpf_allocbufs(struct bpf_d *d) 1989 { 1990 1991 d->bd_fbuf = kmem_alloc(d->bd_bufsize, KM_NOSLEEP); 1992 if (!d->bd_fbuf) 1993 return (ENOBUFS); 1994 d->bd_sbuf = kmem_alloc(d->bd_bufsize, KM_NOSLEEP); 1995 if (!d->bd_sbuf) { 1996 kmem_free(d->bd_fbuf, d->bd_bufsize); 1997 return (ENOBUFS); 1998 } 1999 d->bd_slen = 0; 2000 d->bd_hlen = 0; 2001 return (0); 2002 } 2003 2004 static void 2005 bpf_free_filter(struct bpf_filter *filter) 2006 { 2007 2008 KASSERT(filter != NULL); 2009 KASSERT(filter->bf_insn != NULL); 2010 2011 kmem_free(filter->bf_insn, filter->bf_size); 2012 if (filter->bf_jitcode != NULL) 2013 bpf_jit_freecode(filter->bf_jitcode); 2014 kmem_free(filter, sizeof(*filter)); 2015 } 2016 2017 /* 2018 * Free buffers currently in use by a descriptor. 2019 * Called on close. 2020 */ 2021 static void 2022 bpf_freed(struct bpf_d *d) 2023 { 2024 /* 2025 * We don't need to lock out interrupts since this descriptor has 2026 * been detached from its interface and it yet hasn't been marked 2027 * free. 2028 */ 2029 if (d->bd_sbuf != NULL) { 2030 kmem_free(d->bd_sbuf, d->bd_bufsize); 2031 if (d->bd_hbuf != NULL) 2032 kmem_free(d->bd_hbuf, d->bd_bufsize); 2033 if (d->bd_fbuf != NULL) 2034 kmem_free(d->bd_fbuf, d->bd_bufsize); 2035 } 2036 if (d->bd_filter != NULL) { 2037 bpf_free_filter(d->bd_filter); 2038 d->bd_filter = NULL; 2039 } 2040 d->bd_jitcode = NULL; 2041 } 2042 2043 /* 2044 * Attach an interface to bpf. dlt is the link layer type; 2045 * hdrlen is the fixed size of the link header for the specified dlt 2046 * (variable length headers not yet supported). 2047 */ 2048 static void 2049 _bpfattach(struct ifnet *ifp, u_int dlt, u_int hdrlen, struct bpf_if **driverp) 2050 { 2051 struct bpf_if *bp; 2052 bp = kmem_alloc(sizeof(*bp), KM_NOSLEEP); 2053 if (bp == NULL) 2054 panic("bpfattach"); 2055 2056 mutex_enter(&bpf_mtx); 2057 bp->bif_driverp = driverp; 2058 bp->bif_ifp = ifp; 2059 bp->bif_dlt = dlt; 2060 bp->bif_si = NULL; 2061 BPF_IFLIST_ENTRY_INIT(bp); 2062 PSLIST_INIT(&bp->bif_dlist_head); 2063 psref_target_init(&bp->bif_psref, bpf_psref_class); 2064 2065 BPF_IFLIST_WRITER_INSERT_HEAD(bp); 2066 2067 *bp->bif_driverp = NULL; 2068 2069 bp->bif_hdrlen = hdrlen; 2070 mutex_exit(&bpf_mtx); 2071 #if 0 2072 printf("bpf: %s attached\n", ifp->if_xname); 2073 #endif 2074 } 2075 2076 static void 2077 _bpf_mtap_softint_init(struct ifnet *ifp) 2078 { 2079 struct bpf_if *bp; 2080 2081 mutex_enter(&bpf_mtx); 2082 BPF_IFLIST_WRITER_FOREACH(bp) { 2083 if (bp->bif_ifp != ifp) 2084 continue; 2085 2086 bp->bif_mbuf_head = NULL; 2087 bp->bif_mbuf_tail = NULL; 2088 bp->bif_si = softint_establish(SOFTINT_NET, bpf_mtap_si, bp); 2089 if (bp->bif_si == NULL) 2090 panic("%s: softint_establish() failed", __func__); 2091 break; 2092 } 2093 mutex_exit(&bpf_mtx); 2094 2095 if (bp == NULL) 2096 panic("%s: no bpf_if found for %s", __func__, ifp->if_xname); 2097 } 2098 2099 /* 2100 * Remove an interface from bpf. 2101 */ 2102 static void 2103 _bpfdetach(struct ifnet *ifp) 2104 { 2105 struct bpf_if *bp; 2106 struct bpf_d *d; 2107 int s; 2108 2109 mutex_enter(&bpf_mtx); 2110 /* Nuke the vnodes for any open instances */ 2111 again_d: 2112 BPF_DLIST_WRITER_FOREACH(d) { 2113 mutex_enter(d->bd_mtx); 2114 if (d->bd_bif != NULL && d->bd_bif->bif_ifp == ifp) { 2115 /* 2116 * Detach the descriptor from an interface now. 2117 * It will be free'ed later by close routine. 2118 */ 2119 d->bd_promisc = 0; /* we can't touch device. */ 2120 bpf_detachd(d); 2121 mutex_exit(d->bd_mtx); 2122 goto again_d; 2123 } 2124 mutex_exit(d->bd_mtx); 2125 } 2126 2127 again: 2128 BPF_IFLIST_WRITER_FOREACH(bp) { 2129 if (bp->bif_ifp == ifp) { 2130 BPF_IFLIST_WRITER_REMOVE(bp); 2131 2132 pserialize_perform(bpf_psz); 2133 psref_target_destroy(&bp->bif_psref, bpf_psref_class); 2134 2135 BPF_IFLIST_ENTRY_DESTROY(bp); 2136 if (bp->bif_si != NULL) { 2137 /* XXX NOMPSAFE: assumed running on one CPU */ 2138 s = splnet(); 2139 while (bp->bif_mbuf_head != NULL) { 2140 struct mbuf *m = bp->bif_mbuf_head; 2141 bp->bif_mbuf_head = m->m_nextpkt; 2142 m_freem(m); 2143 } 2144 splx(s); 2145 softint_disestablish(bp->bif_si); 2146 } 2147 kmem_free(bp, sizeof(*bp)); 2148 goto again; 2149 } 2150 } 2151 mutex_exit(&bpf_mtx); 2152 } 2153 2154 /* 2155 * Change the data link type of a interface. 2156 */ 2157 static void 2158 _bpf_change_type(struct ifnet *ifp, u_int dlt, u_int hdrlen) 2159 { 2160 struct bpf_if *bp; 2161 2162 mutex_enter(&bpf_mtx); 2163 BPF_IFLIST_WRITER_FOREACH(bp) { 2164 if (bp->bif_driverp == &ifp->if_bpf) 2165 break; 2166 } 2167 if (bp == NULL) 2168 panic("bpf_change_type"); 2169 2170 bp->bif_dlt = dlt; 2171 2172 bp->bif_hdrlen = hdrlen; 2173 mutex_exit(&bpf_mtx); 2174 } 2175 2176 /* 2177 * Get a list of available data link type of the interface. 2178 */ 2179 static int 2180 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl) 2181 { 2182 int n, error; 2183 struct ifnet *ifp; 2184 struct bpf_if *bp; 2185 int s, bound; 2186 2187 KASSERT(mutex_owned(d->bd_mtx)); 2188 2189 ifp = d->bd_bif->bif_ifp; 2190 n = 0; 2191 error = 0; 2192 2193 bound = curlwp_bind(); 2194 s = pserialize_read_enter(); 2195 BPF_IFLIST_READER_FOREACH(bp) { 2196 if (bp->bif_ifp != ifp) 2197 continue; 2198 if (bfl->bfl_list != NULL) { 2199 struct psref psref; 2200 2201 if (n >= bfl->bfl_len) { 2202 pserialize_read_exit(s); 2203 return ENOMEM; 2204 } 2205 2206 bpf_if_acquire(bp, &psref); 2207 pserialize_read_exit(s); 2208 2209 error = copyout(&bp->bif_dlt, 2210 bfl->bfl_list + n, sizeof(u_int)); 2211 2212 s = pserialize_read_enter(); 2213 bpf_if_release(bp, &psref); 2214 } 2215 n++; 2216 } 2217 pserialize_read_exit(s); 2218 curlwp_bindx(bound); 2219 2220 bfl->bfl_len = n; 2221 return error; 2222 } 2223 2224 /* 2225 * Set the data link type of a BPF instance. 2226 */ 2227 static int 2228 bpf_setdlt(struct bpf_d *d, u_int dlt) 2229 { 2230 int error, opromisc; 2231 struct ifnet *ifp; 2232 struct bpf_if *bp; 2233 2234 KASSERT(mutex_owned(&bpf_mtx)); 2235 KASSERT(mutex_owned(d->bd_mtx)); 2236 2237 if (d->bd_bif->bif_dlt == dlt) 2238 return 0; 2239 ifp = d->bd_bif->bif_ifp; 2240 BPF_IFLIST_WRITER_FOREACH(bp) { 2241 if (bp->bif_ifp == ifp && bp->bif_dlt == dlt) 2242 break; 2243 } 2244 if (bp == NULL) 2245 return EINVAL; 2246 opromisc = d->bd_promisc; 2247 bpf_detachd(d); 2248 BPFIF_DLIST_ENTRY_INIT(d); 2249 bpf_attachd(d, bp); 2250 reset_d(d); 2251 if (opromisc) { 2252 #ifndef NET_MPSAFE 2253 KERNEL_LOCK(1, NULL); 2254 #endif 2255 error = ifpromisc(bp->bif_ifp, 1); 2256 #ifndef NET_MPSAFE 2257 KERNEL_UNLOCK_ONE(NULL); 2258 #endif 2259 if (error) 2260 printf("%s: bpf_setdlt: ifpromisc failed (%d)\n", 2261 bp->bif_ifp->if_xname, error); 2262 else 2263 d->bd_promisc = 1; 2264 } 2265 return 0; 2266 } 2267 2268 static int 2269 sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS) 2270 { 2271 int newsize, error; 2272 struct sysctlnode node; 2273 2274 node = *rnode; 2275 node.sysctl_data = &newsize; 2276 newsize = bpf_maxbufsize; 2277 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2278 if (error || newp == NULL) 2279 return (error); 2280 2281 if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE) 2282 return (EINVAL); 2283 2284 bpf_maxbufsize = newsize; 2285 2286 return (0); 2287 } 2288 2289 #if defined(MODULAR) || defined(BPFJIT) 2290 static int 2291 sysctl_net_bpf_jit(SYSCTLFN_ARGS) 2292 { 2293 bool newval; 2294 int error; 2295 struct sysctlnode node; 2296 2297 node = *rnode; 2298 node.sysctl_data = &newval; 2299 newval = bpf_jit; 2300 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2301 if (error != 0 || newp == NULL) 2302 return error; 2303 2304 bpf_jit = newval; 2305 2306 /* 2307 * Do a full sync to publish new bpf_jit value and 2308 * update bpfjit_module_ops.bj_generate_code variable. 2309 */ 2310 membar_sync(); 2311 2312 if (newval && bpfjit_module_ops.bj_generate_code == NULL) { 2313 printf("JIT compilation is postponed " 2314 "until after bpfjit module is loaded\n"); 2315 } 2316 2317 return 0; 2318 } 2319 #endif 2320 2321 static int 2322 sysctl_net_bpf_peers(SYSCTLFN_ARGS) 2323 { 2324 int error, elem_count; 2325 struct bpf_d *dp; 2326 struct bpf_d_ext dpe; 2327 size_t len, needed, elem_size, out_size; 2328 char *sp; 2329 2330 if (namelen == 1 && name[0] == CTL_QUERY) 2331 return (sysctl_query(SYSCTLFN_CALL(rnode))); 2332 2333 if (namelen != 2) 2334 return (EINVAL); 2335 2336 /* BPF peers is privileged information. */ 2337 error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_INTERFACE, 2338 KAUTH_REQ_NETWORK_INTERFACE_GETPRIV, NULL, NULL, NULL); 2339 if (error) 2340 return (EPERM); 2341 2342 len = (oldp != NULL) ? *oldlenp : 0; 2343 sp = oldp; 2344 elem_size = name[0]; 2345 elem_count = name[1]; 2346 out_size = MIN(sizeof(dpe), elem_size); 2347 needed = 0; 2348 2349 if (elem_size < 1 || elem_count < 0) 2350 return (EINVAL); 2351 2352 mutex_enter(&bpf_mtx); 2353 BPF_DLIST_WRITER_FOREACH(dp) { 2354 if (len >= elem_size && elem_count > 0) { 2355 #define BPF_EXT(field) dpe.bde_ ## field = dp->bd_ ## field 2356 BPF_EXT(bufsize); 2357 BPF_EXT(promisc); 2358 BPF_EXT(state); 2359 BPF_EXT(immediate); 2360 BPF_EXT(hdrcmplt); 2361 BPF_EXT(seesent); 2362 BPF_EXT(pid); 2363 BPF_EXT(rcount); 2364 BPF_EXT(dcount); 2365 BPF_EXT(ccount); 2366 #undef BPF_EXT 2367 mutex_enter(dp->bd_mtx); 2368 if (dp->bd_bif) 2369 (void)strlcpy(dpe.bde_ifname, 2370 dp->bd_bif->bif_ifp->if_xname, 2371 IFNAMSIZ - 1); 2372 else 2373 dpe.bde_ifname[0] = '\0'; 2374 mutex_exit(dp->bd_mtx); 2375 2376 error = copyout(&dpe, sp, out_size); 2377 if (error) 2378 break; 2379 sp += elem_size; 2380 len -= elem_size; 2381 } 2382 needed += elem_size; 2383 if (elem_count > 0 && elem_count != INT_MAX) 2384 elem_count--; 2385 } 2386 mutex_exit(&bpf_mtx); 2387 2388 *oldlenp = needed; 2389 2390 return (error); 2391 } 2392 2393 static void 2394 bpf_stats(void *p, void *arg, struct cpu_info *ci __unused) 2395 { 2396 struct bpf_stat *const stats = p; 2397 struct bpf_stat *sum = arg; 2398 2399 sum->bs_recv += stats->bs_recv; 2400 sum->bs_drop += stats->bs_drop; 2401 sum->bs_capt += stats->bs_capt; 2402 } 2403 2404 static int 2405 bpf_sysctl_gstats_handler(SYSCTLFN_ARGS) 2406 { 2407 struct sysctlnode node; 2408 int error; 2409 struct bpf_stat sum; 2410 2411 memset(&sum, 0, sizeof(sum)); 2412 node = *rnode; 2413 2414 percpu_foreach(bpf_gstats_percpu, bpf_stats, &sum); 2415 2416 node.sysctl_data = ∑ 2417 node.sysctl_size = sizeof(sum); 2418 error = sysctl_lookup(SYSCTLFN_CALL(&node)); 2419 if (error != 0 || newp == NULL) 2420 return error; 2421 2422 return 0; 2423 } 2424 2425 static struct sysctllog *bpf_sysctllog; 2426 static void 2427 sysctl_net_bpf_setup(void) 2428 { 2429 const struct sysctlnode *node; 2430 2431 node = NULL; 2432 sysctl_createv(&bpf_sysctllog, 0, NULL, &node, 2433 CTLFLAG_PERMANENT, 2434 CTLTYPE_NODE, "bpf", 2435 SYSCTL_DESCR("BPF options"), 2436 NULL, 0, NULL, 0, 2437 CTL_NET, CTL_CREATE, CTL_EOL); 2438 if (node != NULL) { 2439 #if defined(MODULAR) || defined(BPFJIT) 2440 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2441 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2442 CTLTYPE_BOOL, "jit", 2443 SYSCTL_DESCR("Toggle Just-In-Time compilation"), 2444 sysctl_net_bpf_jit, 0, &bpf_jit, 0, 2445 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2446 #endif 2447 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2448 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 2449 CTLTYPE_INT, "maxbufsize", 2450 SYSCTL_DESCR("Maximum size for data capture buffer"), 2451 sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0, 2452 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2453 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2454 CTLFLAG_PERMANENT, 2455 CTLTYPE_STRUCT, "stats", 2456 SYSCTL_DESCR("BPF stats"), 2457 bpf_sysctl_gstats_handler, 0, NULL, 0, 2458 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2459 sysctl_createv(&bpf_sysctllog, 0, NULL, NULL, 2460 CTLFLAG_PERMANENT, 2461 CTLTYPE_STRUCT, "peers", 2462 SYSCTL_DESCR("BPF peers"), 2463 sysctl_net_bpf_peers, 0, NULL, 0, 2464 CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL); 2465 } 2466 2467 } 2468 2469 struct bpf_ops bpf_ops_kernel = { 2470 .bpf_attach = _bpfattach, 2471 .bpf_detach = _bpfdetach, 2472 .bpf_change_type = _bpf_change_type, 2473 2474 .bpf_tap = _bpf_tap, 2475 .bpf_mtap = _bpf_mtap, 2476 .bpf_mtap2 = _bpf_mtap2, 2477 .bpf_mtap_af = _bpf_mtap_af, 2478 .bpf_mtap_sl_in = _bpf_mtap_sl_in, 2479 .bpf_mtap_sl_out = _bpf_mtap_sl_out, 2480 2481 .bpf_mtap_softint = _bpf_mtap_softint, 2482 .bpf_mtap_softint_init = _bpf_mtap_softint_init, 2483 }; 2484 2485 MODULE(MODULE_CLASS_DRIVER, bpf, "bpf_filter"); 2486 2487 static int 2488 bpf_modcmd(modcmd_t cmd, void *arg) 2489 { 2490 #ifdef _MODULE 2491 devmajor_t bmajor, cmajor; 2492 #endif 2493 int error = 0; 2494 2495 switch (cmd) { 2496 case MODULE_CMD_INIT: 2497 bpf_init(); 2498 #ifdef _MODULE 2499 bmajor = cmajor = NODEVMAJOR; 2500 error = devsw_attach("bpf", NULL, &bmajor, 2501 &bpf_cdevsw, &cmajor); 2502 if (error) 2503 break; 2504 #endif 2505 2506 bpf_ops_handover_enter(&bpf_ops_kernel); 2507 atomic_swap_ptr(&bpf_ops, &bpf_ops_kernel); 2508 bpf_ops_handover_exit(); 2509 sysctl_net_bpf_setup(); 2510 break; 2511 2512 case MODULE_CMD_FINI: 2513 /* 2514 * While there is no reference counting for bpf callers, 2515 * unload could at least in theory be done similarly to 2516 * system call disestablishment. This should even be 2517 * a little simpler: 2518 * 2519 * 1) replace op vector with stubs 2520 * 2) post update to all cpus with xc 2521 * 3) check that nobody is in bpf anymore 2522 * (it's doubtful we'd want something like l_sysent, 2523 * but we could do something like *signed* percpu 2524 * counters. if the sum is 0, we're good). 2525 * 4) if fail, unroll changes 2526 * 2527 * NOTE: change won't be atomic to the outside. some 2528 * packets may be not captured even if unload is 2529 * not succesful. I think packet capture not working 2530 * is a perfectly logical consequence of trying to 2531 * disable packet capture. 2532 */ 2533 error = EOPNOTSUPP; 2534 /* insert sysctl teardown */ 2535 break; 2536 2537 default: 2538 error = ENOTTY; 2539 break; 2540 } 2541 2542 return error; 2543 } 2544
Indexes created Tue Sep 23 13:09:54 GMT 2025