bsd/kern/kpi_socketfilter.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #include <sys/kpi_socketfilter.h>
  30
  31 #include <sys/socket.h>
  32 #include <sys/param.h>
  33 #include <sys/errno.h>
  34 #include <sys/malloc.h>
  35 #include <sys/protosw.h>
  36 #include <kern/locks.h>
  37 #include <net/kext_net.h>
  38
  39 static struct socket_filter_list        sock_filter_head;
  40 static lck_mtx_t                                        *sock_filter_lock = 0;
  41
  42 static void     sflt_detach_private(struct socket_filter_entry *entry, int unregistering);
  43
  44 __private_extern__ void
  45 sflt_init(void)
  46 {
  47         lck_grp_attr_t  *grp_attrib = 0;
  48         lck_attr_t              *lck_attrib = 0;
  49         lck_grp_t               *lck_group = 0;
  50
  51         TAILQ_INIT(&sock_filter_head);
  52
  53         /* Allocate a spin lock */
  54         grp_attrib = lck_grp_attr_alloc_init();
  55         lck_group = lck_grp_alloc_init("socket filter lock", grp_attrib);
  56         lck_grp_attr_free(grp_attrib);
  57         lck_attrib = lck_attr_alloc_init();
  58         sock_filter_lock = lck_mtx_alloc_init(lck_group, lck_attrib);
  59         lck_grp_free(lck_group);
  60         lck_attr_free(lck_attrib);
  61 }
  62
  63 __private_extern__ void
  64 sflt_initsock(
  65         struct socket *so)
  66 {
  67         struct protosw *proto = so->so_proto;
  68         struct socket_filter *filter;
  69
  70         if (TAILQ_FIRST(&proto->pr_filter_head) != NULL) {
  71                 lck_mtx_lock(sock_filter_lock);
  72                 TAILQ_FOREACH(filter, &proto->pr_filter_head, sf_protosw_next) {
  73                         sflt_attach_private(so, filter, 0, 0);
  74                 }
  75                 lck_mtx_unlock(sock_filter_lock);
  76         }
  77 }
  78
  79 __private_extern__ void
  80 sflt_termsock(
  81         struct socket *so)
  82 {
  83         struct socket_filter_entry *filter;
  84         struct socket_filter_entry *filter_next;
  85
  86         for (filter = so->so_filt; filter; filter = filter_next) {
  87                 filter_next = filter->sfe_next_onsocket;
  88                 sflt_detach_private(filter, 0);
  89         }
  90         so->so_filt = NULL;
  91 }
  92
  93 __private_extern__ void
  94 sflt_use(
  95         struct socket *so)
  96 {
  97         so->so_filteruse++;
  98 }
  99
 100 __private_extern__ void
 101 sflt_unuse(
 102         struct socket *so)
 103 {
 104         so->so_filteruse--;
 105         if (so->so_filteruse == 0) {
 106                 struct socket_filter_entry *filter;
 107                 struct socket_filter_entry *next_filter;
 108                 // search for detaching filters
 109                 for (filter = so->so_filt; filter; filter = next_filter) {
 110                         next_filter = filter->sfe_next_onsocket;
 111
 112                         if (filter->sfe_flags & SFEF_DETACHUSEZERO) {
 113                                 sflt_detach_private(filter, 0);
 114                         }
 115                 }
 116         }
 117 }
 118
 119 __private_extern__ void
 120 sflt_notify(
 121         struct socket   *so,
 122         sflt_event_t    event,
 123         void                    *param)
 124 {
 125         struct socket_filter_entry      *filter;
 126         int                                                     filtered = 0;
 127
 128         for (filter = so->so_filt; filter;
 129                  filter = filter->sfe_next_onsocket) {
 130                 if (filter->sfe_filter->sf_filter.sf_notify) {
 131                         if (filtered == 0) {
 132                                 filtered = 1;
 133                                 sflt_use(so);
 134                                 socket_unlock(so, 0);
 135                         }
 136                         filter->sfe_filter->sf_filter.sf_notify(
 137                                 filter->sfe_cookie, so, event, param);
 138                 }
 139         }
 140
 141         if (filtered != 0) {
 142                 socket_lock(so, 0);
 143                 sflt_unuse(so);
 144         }
 145 }
 146
 147 __private_extern__ int
 148 sflt_data_in(
 149         struct socket                   *so,
 150         const struct sockaddr   *from,
 151         mbuf_t                                  *data,
 152         mbuf_t                                  *control,
 153         sflt_data_flag_t                flags,
 154         int                                             *filtered)
 155 {
 156         struct socket_filter_entry      *filter;
 157         int                                                     error = 0;
 158         int                                                     filtered_storage;
 159
 160         if (filtered == NULL)
 161                 filtered = &filtered_storage;
 162         *filtered = 0;
 163
 164         for (filter = so->so_filt; filter && (error == 0);
 165                  filter = filter->sfe_next_onsocket) {
 166                 if (filter->sfe_filter->sf_filter.sf_data_in) {
 167                         if (*filtered == 0) {
 168                                 *filtered = 1;
 169                                 sflt_use(so);
 170                                 socket_unlock(so, 0);
 171                         }
 172                         error = filter->sfe_filter->sf_filter.sf_data_in(
 173                                                 filter->sfe_cookie, so, from, data, control, flags);
 174                 }
 175         }
 176
 177         if (*filtered != 0) {
 178                 socket_lock(so, 0);
 179                 sflt_unuse(so);
 180         }
 181
 182         return error;
 183 }
 184
 185 /* sflt_attach_private
 186  *
 187  * Assumptions: If filter is not NULL, socket_filter_lock is held.
 188  */
 189
 190 __private_extern__ int
 191 sflt_attach_private(
 192         struct socket *so,
 193         struct socket_filter *filter,
 194         sflt_handle                     handle,
 195         int sock_locked)
 196 {
 197         struct socket_filter_entry *entry = NULL;
 198         int didlock = 0;
 199         int error = 0;
 200
 201         if (filter == NULL) {
 202                 /* Find the filter by the handle */
 203                 lck_mtx_lock(sock_filter_lock);
 204                 didlock = 1;
 205
 206                 TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 207                         if (filter->sf_filter.sf_handle == handle)
 208                                 break;
 209                 }
 210         }
 211
 212         if (filter == NULL)
 213                 error = ENOENT;
 214
 215         if (error == 0) {
 216                 /* allocate the socket filter entry */
 217                 MALLOC(entry, struct socket_filter_entry *, sizeof(*entry), M_IFADDR, M_WAITOK);
 218                 if (entry == NULL) {
 219                         error = ENOMEM;
 220                 }
 221         }
 222
 223         if (error == 0) {
 224                 /* Initialize the socket filter entry and call the attach function */
 225                 entry->sfe_filter = filter;
 226                 entry->sfe_socket = so;
 227                 entry->sfe_cookie = NULL;
 228                 entry->sfe_flags = 0;
 229                 if (entry->sfe_filter->sf_filter.sf_attach) {
 230                         filter->sf_usecount++;
 231
 232                         if (sock_locked)
 233                                 socket_unlock(so, 0);
 234                         error = entry->sfe_filter->sf_filter.sf_attach(&entry->sfe_cookie, so);
 235                         if (sock_locked)
 236                                 socket_lock(so, 0);
 237
 238                         filter->sf_usecount--;
 239
 240                         /* If the attach function returns an error, this filter is not attached */
 241                         if (error) {
 242                                 FREE(entry, M_IFADDR);
 243                                 entry = NULL;
 244                         }
 245                 }
 246         }
 247
 248         if (error == 0) {
 249                 /* Put the entry in the socket list */
 250                 entry->sfe_next_onsocket = so->so_filt;
 251                 so->so_filt = entry;
 252
 253                 /* Put the entry in the filter list */
 254                 entry->sfe_next_onfilter = filter->sf_entry_head;
 255                 filter->sf_entry_head = entry;
 256
 257                 /* Incremenet the parent filter's usecount */
 258                 filter->sf_usecount++;
 259         }
 260
 261         if (didlock) {
 262                 lck_mtx_unlock(sock_filter_lock);
 263         }
 264
 265         return error;
 266 }
 267
 268
 269 /* sflt_detach_private
 270  *
 271  * Assumptions: if you pass 0 in for the second parameter, you are holding the
 272  * socket lock for the socket the entry is attached to. If you pass 1 in for
 273  * the second parameter, it is assumed that the entry is not on the filter's
 274  * list and the socket lock is not held.
 275  */
 276
 277 static void
 278 sflt_detach_private(
 279         struct socket_filter_entry *entry,
 280         int     unregistering)
 281 {
 282         struct socket *so = entry->sfe_socket;
 283         struct socket_filter_entry **next_ptr;
 284         int                             detached = 0;
 285         int                             found = 0;
 286
 287         if (unregistering) {
 288                 socket_lock(entry->sfe_socket, 0);
 289         }
 290
 291         /*
 292          * Attempt to find the entry on the filter's list and
 293          * remove it. This prevents a filter detaching at the
 294          * same time from attempting to remove the same entry.
 295          */
 296         lck_mtx_lock(sock_filter_lock);
 297         if (!unregistering) {
 298                 if ((entry->sfe_flags & SFEF_UNREGISTERING) != 0) {
 299                         /*
 300                          * Another thread is unregistering the filter, we need to
 301                          * avoid detaching the filter here so the socket won't go
 302                          * away.
 303                          */
 304                         lck_mtx_unlock(sock_filter_lock);
 305                         return;
 306                 }
 307                 for (next_ptr = &entry->sfe_filter->sf_entry_head; *next_ptr;
 308                          next_ptr = &((*next_ptr)->sfe_next_onfilter)) {
 309                         if (*next_ptr == entry) {
 310                                 found = 1;
 311                                 *next_ptr = entry->sfe_next_onfilter;
 312                                 break;
 313                         }
 314                 }
 315
 316                 if (!found && (entry->sfe_flags & SFEF_DETACHUSEZERO) == 0) {
 317                         lck_mtx_unlock(sock_filter_lock);
 318                         return;
 319                 }
 320         }
 321         else {
 322                 /*
 323                  * Clear the removing flag. We will perform the detach here or
 324                  * request a delayed deatch.
 325                  */
 326                 entry->sfe_flags &= ~SFEF_UNREGISTERING;
 327         }
 328
 329         if (entry->sfe_socket->so_filteruse != 0) {
 330                 entry->sfe_flags |= SFEF_DETACHUSEZERO;
 331                 lck_mtx_unlock(sock_filter_lock);
 332                 return;
 333         }
 334         else {
 335                 /*
 336                  * Check if we are removing the last attached filter and
 337                  * the parent filter is being unregistered.
 338                  */
 339                 entry->sfe_filter->sf_usecount--;
 340                 if ((entry->sfe_filter->sf_usecount == 0) &&
 341                         (entry->sfe_filter->sf_flags & SFF_DETACHING) != 0)
 342                         detached = 1;
 343         }
 344         lck_mtx_unlock(sock_filter_lock);
 345
 346         /* Remove from the socket list */
 347         for (next_ptr = &entry->sfe_socket->so_filt; *next_ptr;
 348                  next_ptr = &((*next_ptr)->sfe_next_onsocket)) {
 349                 if (*next_ptr == entry) {
 350                         *next_ptr = entry->sfe_next_onsocket;
 351                         break;
 352                 }
 353         }
 354
 355         if (entry->sfe_filter->sf_filter.sf_detach)
 356                 entry->sfe_filter->sf_filter.sf_detach(entry->sfe_cookie, entry->sfe_socket);
 357
 358         if (detached && entry->sfe_filter->sf_filter.sf_unregistered) {
 359                 entry->sfe_filter->sf_filter.sf_unregistered(entry->sfe_filter->sf_filter.sf_handle);
 360                 FREE(entry->sfe_filter, M_IFADDR);
 361         }
 362
 363         if (unregistering)
 364                 socket_unlock(entry->sfe_socket, 1);
 365
 366         FREE(entry, M_IFADDR);
 367 }
 368
 369 errno_t
 370 sflt_attach(
 371         socket_t        socket,
 372         sflt_handle     handle)
 373 {
 374         if (socket == NULL || handle == 0)
 375                 return EINVAL;
 376
 377         return sflt_attach_private(socket, NULL, handle, 0);
 378 }
 379
 380 errno_t
 381 sflt_detach(
 382         socket_t        socket,
 383         sflt_handle     handle)
 384 {
 385         struct socket_filter_entry      *filter;
 386         errno_t result = 0;
 387
 388         if (socket == NULL || handle == 0)
 389                 return EINVAL;
 390
 391         socket_lock(socket, 1);
 392
 393         for (filter = socket->so_filt; filter;
 394                  filter = filter->sfe_next_onsocket) {
 395                 if (filter->sfe_filter->sf_filter.sf_handle == handle)
 396                         break;
 397         }
 398
 399         if (filter != NULL) {
 400                 sflt_detach_private(filter, 0);
 401         }
 402         else {
 403                 socket->so_filt = NULL;
 404                 result = ENOENT;
 405         }
 406
 407         socket_unlock(socket, 1);
 408
 409         return result;
 410 }
 411
 412
 413 errno_t
 414 sflt_register(
 415         const struct sflt_filter        *filter,
 416         int                                                     domain,
 417         int                                                     type,
 418         int                                                     protocol)
 419 {
 420         struct socket_filter *sock_filt = NULL;
 421         struct socket_filter *match = NULL;
 422         int error = 0;
 423         struct protosw *pr = pffindproto(domain, protocol, type);
 424
 425         if (pr == NULL) return ENOENT;
 426
 427         if (filter->sf_attach == NULL || filter->sf_detach == NULL) return EINVAL;
 428         if (filter->sf_handle == 0) return EINVAL;
 429         if (filter->sf_name == NULL) return EINVAL;
 430
 431         /* Allocate the socket filter */
 432         MALLOC(sock_filt, struct socket_filter*, sizeof(*sock_filt), M_IFADDR, M_WAITOK);
 433         if (sock_filt == NULL) {
 434                 return ENOBUFS;
 435         }
 436
 437         bzero(sock_filt, sizeof(*sock_filt));
 438         sock_filt->sf_filter = *filter;
 439
 440         lck_mtx_lock(sock_filter_lock);
 441         /* Look for an existing entry */
 442         TAILQ_FOREACH(match, &sock_filter_head, sf_global_next) {
 443                 if (match->sf_filter.sf_handle == sock_filt->sf_filter.sf_handle) {
 444                         break;
 445                 }
 446         }
 447
 448         /* Add the entry only if there was no existing entry */
 449         if (match == NULL) {
 450                 TAILQ_INSERT_TAIL(&sock_filter_head, sock_filt, sf_global_next);
 451                 if ((sock_filt->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 452                         TAILQ_INSERT_TAIL(&pr->pr_filter_head, sock_filt, sf_protosw_next);
 453                         sock_filt->sf_proto = pr;
 454                 }
 455         }
 456         lck_mtx_unlock(sock_filter_lock);
 457
 458         if (match != NULL) {
 459                 FREE(sock_filt, M_IFADDR);
 460                 return EEXIST;
 461         }
 462
 463         return error;
 464 }
 465
 466 errno_t
 467 sflt_unregister(
 468         sflt_handle handle)
 469 {
 470         struct socket_filter *filter;
 471         struct socket_filter_entry *entry_head = NULL;
 472         struct socket_filter_entry *next_entry = NULL;
 473
 474         /* Find the entry and remove it from the global and protosw lists */
 475         lck_mtx_lock(sock_filter_lock);
 476         TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 477                 if (filter->sf_filter.sf_handle == handle)
 478                         break;
 479         }
 480
 481         if (filter) {
 482                 TAILQ_REMOVE(&sock_filter_head, filter, sf_global_next);
 483                 if ((filter->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 484                         TAILQ_REMOVE(&filter->sf_proto->pr_filter_head, filter, sf_protosw_next);
 485                 }
 486                 entry_head = filter->sf_entry_head;
 487                 filter->sf_entry_head = NULL;
 488                 filter->sf_flags |= SFF_DETACHING;
 489
 490                 for (next_entry = entry_head; next_entry;
 491                          next_entry = next_entry->sfe_next_onfilter) {
 492                         socket_lock(next_entry->sfe_socket, 1);
 493                         next_entry->sfe_flags |= SFEF_UNREGISTERING;
 494                         socket_unlock(next_entry->sfe_socket, 0);       /* Radar 4201550: prevents the socket from being deleted while being unregistered */
 495                 }
 496         }
 497
 498         lck_mtx_unlock(sock_filter_lock);
 499
 500         if (filter == NULL)
 501                 return ENOENT;
 502
 503         /* We need to detach the filter from any sockets it's attached to */
 504         if (entry_head == 0) {
 505                 if (filter->sf_filter.sf_unregistered)
 506                         filter->sf_filter.sf_unregistered(filter->sf_filter.sf_handle);
 507         } else {
 508                 while (entry_head) {
 509                         next_entry = entry_head->sfe_next_onfilter;
 510                         sflt_detach_private(entry_head, 1);
 511                         entry_head = next_entry;
 512                 }
 513         }
 514
 515         return 0;
 516 }
 517
 518 errno_t
 519 sock_inject_data_in(
 520         socket_t so,
 521         const struct sockaddr* from,
 522         mbuf_t data,
 523         mbuf_t control,
 524         sflt_data_flag_t flags)
 525 {
 526         int error = 0;
 527         if (so == NULL || data == NULL) return EINVAL;
 528
 529         if (flags & sock_data_filt_flag_oob) {
 530                 return ENOTSUP;
 531         }
 532
 533         socket_lock(so, 1);
 534
 535         if (from) {
 536                 if (sbappendaddr(&so->so_rcv, (struct sockaddr*)from, data,
 537                                                  control, NULL))
 538                         sorwakeup(so);
 539                 goto done;
 540         }
 541
 542         if (control) {
 543                 if (sbappendcontrol(&so->so_rcv, data, control, NULL))
 544                         sorwakeup(so);
 545                 goto done;
 546         }
 547
 548         if (flags & sock_data_filt_flag_record) {
 549                 if (control || from) {
 550                         error = EINVAL;
 551                         goto done;
 552                 }
 553                 if (sbappendrecord(&so->so_rcv, (struct mbuf*)data))
 554                         sorwakeup(so);
 555                 goto done;
 556         }
 557
 558         if (sbappend(&so->so_rcv, data))
 559                 sorwakeup(so);
 560 done:
 561         socket_unlock(so, 1);
 562         return error;
 563 }
 564
 565 errno_t
 566 sock_inject_data_out(
 567         socket_t so,
 568         const struct sockaddr* to,
 569         mbuf_t data,
 570         mbuf_t control,
 571         sflt_data_flag_t flags)
 572 {
 573         int     sosendflags = 0;
 574         if (flags & sock_data_filt_flag_oob) sosendflags = MSG_OOB;
 575         return sosend(so, (const struct sockaddr*)to, NULL,
 576                                   data, control, sosendflags);
 577 }
 578
 579 sockopt_dir
 580 sockopt_direction(
 581         sockopt_t       sopt)
 582 {
 583         return (sopt->sopt_dir == SOPT_GET) ? sockopt_get : sockopt_set;
 584 }
 585
 586 int
 587 sockopt_level(
 588         sockopt_t       sopt)
 589 {
 590         return sopt->sopt_level;
 591 }
 592
 593 int
 594 sockopt_name(
 595         sockopt_t       sopt)
 596 {
 597         return sopt->sopt_name;
 598 }
 599
 600 size_t
 601 sockopt_valsize(
 602         sockopt_t       sopt)
 603 {
 604         return sopt->sopt_valsize;
 605 }
 606
 607 errno_t
 608 sockopt_copyin(
 609         sockopt_t       sopt,
 610         void *data,
 611         size_t  len)
 612 {
 613         return sooptcopyin(sopt, data, len, len);
 614 }
 615
 616 errno_t
 617 sockopt_copyout(
 618         sockopt_t       sopt,
 619         void *data,
 620         size_t  len)
 621 {
 622         return sooptcopyout(sopt, data, len);
 623 }