bsd/kern/kpi_socketfilter.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 #include <sys/kpi_socketfilter.h>
  32
  33 #include <sys/socket.h>
  34 #include <sys/param.h>
  35 #include <sys/errno.h>
  36 #include <sys/malloc.h>
  37 #include <sys/protosw.h>
  38 #include <kern/locks.h>
  39 #include <net/kext_net.h>
  40
  41 static struct socket_filter_list        sock_filter_head;
  42 static lck_mtx_t                                        *sock_filter_lock = 0;
  43
  44 static void     sflt_detach_private(struct socket_filter_entry *entry, int unregistering);
  45
  46 __private_extern__ void
  47 sflt_init(void)
  48 {
  49         lck_grp_attr_t  *grp_attrib = 0;
  50         lck_attr_t              *lck_attrib = 0;
  51         lck_grp_t               *lck_group = 0;
  52
  53         TAILQ_INIT(&sock_filter_head);
  54
  55         /* Allocate a spin lock */
  56         grp_attrib = lck_grp_attr_alloc_init();
  57         lck_group = lck_grp_alloc_init("socket filter lock", grp_attrib);
  58         lck_grp_attr_free(grp_attrib);
  59         lck_attrib = lck_attr_alloc_init();
  60         sock_filter_lock = lck_mtx_alloc_init(lck_group, lck_attrib);
  61         lck_grp_free(lck_group);
  62         lck_attr_free(lck_attrib);
  63 }
  64
  65 __private_extern__ void
  66 sflt_initsock(
  67         struct socket *so)
  68 {
  69         struct protosw *proto = so->so_proto;
  70         struct socket_filter *filter;
  71
  72         if (TAILQ_FIRST(&proto->pr_filter_head) != NULL) {
  73                 lck_mtx_lock(sock_filter_lock);
  74                 TAILQ_FOREACH(filter, &proto->pr_filter_head, sf_protosw_next) {
  75                         sflt_attach_private(so, filter, 0, 0);
  76                 }
  77                 lck_mtx_unlock(sock_filter_lock);
  78         }
  79 }
  80
  81 __private_extern__ void
  82 sflt_termsock(
  83         struct socket *so)
  84 {
  85         struct socket_filter_entry *filter;
  86         struct socket_filter_entry *filter_next;
  87
  88         for (filter = so->so_filt; filter; filter = filter_next) {
  89                 filter_next = filter->sfe_next_onsocket;
  90                 sflt_detach_private(filter, 0);
  91         }
  92         so->so_filt = NULL;
  93 }
  94
  95 __private_extern__ void
  96 sflt_use(
  97         struct socket *so)
  98 {
  99         so->so_filteruse++;
 100 }
 101
 102 __private_extern__ void
 103 sflt_unuse(
 104         struct socket *so)
 105 {
 106         so->so_filteruse--;
 107         if (so->so_filteruse == 0) {
 108                 struct socket_filter_entry *filter;
 109                 struct socket_filter_entry *next_filter;
 110                 // search for detaching filters
 111                 for (filter = so->so_filt; filter; filter = next_filter) {
 112                         next_filter = filter->sfe_next_onsocket;
 113
 114                         if (filter->sfe_flags & SFEF_DETACHUSEZERO) {
 115                                 sflt_detach_private(filter, 0);
 116                         }
 117                 }
 118         }
 119 }
 120
 121 __private_extern__ void
 122 sflt_notify(
 123         struct socket   *so,
 124         sflt_event_t    event,
 125         void                    *param)
 126 {
 127         struct socket_filter_entry      *filter;
 128         int                                                     filtered = 0;
 129
 130         for (filter = so->so_filt; filter;
 131                  filter = filter->sfe_next_onsocket) {
 132                 if (filter->sfe_filter->sf_filter.sf_notify) {
 133                         if (filtered == 0) {
 134                                 filtered = 1;
 135                                 sflt_use(so);
 136                                 socket_unlock(so, 0);
 137                         }
 138                         filter->sfe_filter->sf_filter.sf_notify(
 139                                 filter->sfe_cookie, so, event, param);
 140                 }
 141         }
 142
 143         if (filtered != 0) {
 144                 socket_lock(so, 0);
 145                 sflt_unuse(so);
 146         }
 147 }
 148
 149 __private_extern__ int
 150 sflt_data_in(
 151         struct socket                   *so,
 152         const struct sockaddr   *from,
 153         mbuf_t                                  *data,
 154         mbuf_t                                  *control,
 155         sflt_data_flag_t                flags,
 156         int                                             *filtered)
 157 {
 158         struct socket_filter_entry      *filter;
 159         int                                                     error = 0;
 160         int                                                     filtered_storage;
 161
 162         if (filtered == NULL)
 163                 filtered = &filtered_storage;
 164         *filtered = 0;
 165
 166         for (filter = so->so_filt; filter && (error == 0);
 167                  filter = filter->sfe_next_onsocket) {
 168                 if (filter->sfe_filter->sf_filter.sf_data_in) {
 169                         if (*filtered == 0) {
 170                                 *filtered = 1;
 171                                 sflt_use(so);
 172                                 socket_unlock(so, 0);
 173                         }
 174                         error = filter->sfe_filter->sf_filter.sf_data_in(
 175                                                 filter->sfe_cookie, so, from, data, control, flags);
 176                 }
 177         }
 178
 179         if (*filtered != 0) {
 180                 socket_lock(so, 0);
 181                 sflt_unuse(so);
 182         }
 183
 184         return error;
 185 }
 186
 187 /* sflt_attach_private
 188  *
 189  * Assumptions: If filter is not NULL, socket_filter_lock is held.
 190  */
 191
 192 __private_extern__ int
 193 sflt_attach_private(
 194         struct socket *so,
 195         struct socket_filter *filter,
 196         sflt_handle                     handle,
 197         int sock_locked)
 198 {
 199         struct socket_filter_entry *entry = NULL;
 200         int didlock = 0;
 201         int error = 0;
 202
 203         if (filter == NULL) {
 204                 /* Find the filter by the handle */
 205                 lck_mtx_lock(sock_filter_lock);
 206                 didlock = 1;
 207
 208                 TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 209                         if (filter->sf_filter.sf_handle == handle)
 210                                 break;
 211                 }
 212         }
 213
 214         if (filter == NULL)
 215                 error = ENOENT;
 216
 217         if (error == 0) {
 218                 /* allocate the socket filter entry */
 219                 MALLOC(entry, struct socket_filter_entry *, sizeof(*entry), M_IFADDR, M_WAITOK);
 220                 if (entry == NULL) {
 221                         error = ENOMEM;
 222                 }
 223         }
 224
 225         if (error == 0) {
 226                 /* Initialize the socket filter entry and call the attach function */
 227                 entry->sfe_filter = filter;
 228                 entry->sfe_socket = so;
 229                 entry->sfe_cookie = NULL;
 230                 entry->sfe_flags = 0;
 231                 if (entry->sfe_filter->sf_filter.sf_attach) {
 232                         filter->sf_usecount++;
 233
 234                         if (sock_locked)
 235                                 socket_unlock(so, 0);
 236                         error = entry->sfe_filter->sf_filter.sf_attach(&entry->sfe_cookie, so);
 237                         if (sock_locked)
 238                                 socket_lock(so, 0);
 239
 240                         filter->sf_usecount--;
 241
 242                         /* If the attach function returns an error, this filter is not attached */
 243                         if (error) {
 244                                 FREE(entry, M_IFADDR);
 245                                 entry = NULL;
 246                         }
 247                 }
 248         }
 249
 250         if (error == 0) {
 251                 /* Put the entry in the socket list */
 252                 entry->sfe_next_onsocket = so->so_filt;
 253                 so->so_filt = entry;
 254
 255                 /* Put the entry in the filter list */
 256                 entry->sfe_next_onfilter = filter->sf_entry_head;
 257                 filter->sf_entry_head = entry;
 258
 259                 /* Incremenet the parent filter's usecount */
 260                 filter->sf_usecount++;
 261         }
 262
 263         if (didlock) {
 264                 lck_mtx_unlock(sock_filter_lock);
 265         }
 266
 267         return error;
 268 }
 269
 270
 271 /* sflt_detach_private
 272  *
 273  * Assumptions: if you pass 0 in for the second parameter, you are holding the
 274  * socket lock for the socket the entry is attached to. If you pass 1 in for
 275  * the second parameter, it is assumed that the entry is not on the filter's
 276  * list and the socket lock is not held.
 277  */
 278
 279 static void
 280 sflt_detach_private(
 281         struct socket_filter_entry *entry,
 282         int     unregistering)
 283 {
 284         struct socket *so = entry->sfe_socket;
 285         struct socket_filter_entry **next_ptr;
 286         int                             detached = 0;
 287         int                             found = 0;
 288
 289         if (unregistering) {
 290                 socket_lock(entry->sfe_socket, 0);
 291         }
 292
 293         /*
 294          * Attempt to find the entry on the filter's list and
 295          * remove it. This prevents a filter detaching at the
 296          * same time from attempting to remove the same entry.
 297          */
 298         lck_mtx_lock(sock_filter_lock);
 299         if (!unregistering) {
 300                 if ((entry->sfe_flags & SFEF_UNREGISTERING) != 0) {
 301                         /*
 302                          * Another thread is unregistering the filter, we need to
 303                          * avoid detaching the filter here so the socket won't go
 304                          * away.
 305                          */
 306                         lck_mtx_unlock(sock_filter_lock);
 307                         return;
 308                 }
 309                 for (next_ptr = &entry->sfe_filter->sf_entry_head; *next_ptr;
 310                          next_ptr = &((*next_ptr)->sfe_next_onfilter)) {
 311                         if (*next_ptr == entry) {
 312                                 found = 1;
 313                                 *next_ptr = entry->sfe_next_onfilter;
 314                                 break;
 315                         }
 316                 }
 317
 318                 if (!found && (entry->sfe_flags & SFEF_DETACHUSEZERO) == 0) {
 319                         lck_mtx_unlock(sock_filter_lock);
 320                         return;
 321                 }
 322         }
 323         else {
 324                 /*
 325                  * Clear the removing flag. We will perform the detach here or
 326                  * request a delayed deatch.
 327                  */
 328                 entry->sfe_flags &= ~SFEF_UNREGISTERING;
 329         }
 330
 331         if (entry->sfe_socket->so_filteruse != 0) {
 332                 entry->sfe_flags |= SFEF_DETACHUSEZERO;
 333                 lck_mtx_unlock(sock_filter_lock);
 334                 return;
 335         }
 336         else {
 337                 /*
 338                  * Check if we are removing the last attached filter and
 339                  * the parent filter is being unregistered.
 340                  */
 341                 entry->sfe_filter->sf_usecount--;
 342                 if ((entry->sfe_filter->sf_usecount == 0) &&
 343                         (entry->sfe_filter->sf_flags & SFF_DETACHING) != 0)
 344                         detached = 1;
 345         }
 346         lck_mtx_unlock(sock_filter_lock);
 347
 348         /* Remove from the socket list */
 349         for (next_ptr = &entry->sfe_socket->so_filt; *next_ptr;
 350                  next_ptr = &((*next_ptr)->sfe_next_onsocket)) {
 351                 if (*next_ptr == entry) {
 352                         *next_ptr = entry->sfe_next_onsocket;
 353                         break;
 354                 }
 355         }
 356
 357         if (entry->sfe_filter->sf_filter.sf_detach)
 358                 entry->sfe_filter->sf_filter.sf_detach(entry->sfe_cookie, entry->sfe_socket);
 359
 360         if (detached && entry->sfe_filter->sf_filter.sf_unregistered) {
 361                 entry->sfe_filter->sf_filter.sf_unregistered(entry->sfe_filter->sf_filter.sf_handle);
 362                 FREE(entry->sfe_filter, M_IFADDR);
 363         }
 364
 365         if (unregistering)
 366                 socket_unlock(entry->sfe_socket, 1);
 367
 368         FREE(entry, M_IFADDR);
 369 }
 370
 371 errno_t
 372 sflt_attach(
 373         socket_t        socket,
 374         sflt_handle     handle)
 375 {
 376         if (socket == NULL || handle == 0)
 377                 return EINVAL;
 378
 379         return sflt_attach_private(socket, NULL, handle, 0);
 380 }
 381
 382 errno_t
 383 sflt_detach(
 384         socket_t        socket,
 385         sflt_handle     handle)
 386 {
 387         struct socket_filter_entry      *filter;
 388         errno_t result = 0;
 389
 390         if (socket == NULL || handle == 0)
 391                 return EINVAL;
 392
 393         socket_lock(socket, 1);
 394
 395         for (filter = socket->so_filt; filter;
 396                  filter = filter->sfe_next_onsocket) {
 397                 if (filter->sfe_filter->sf_filter.sf_handle == handle)
 398                         break;
 399         }
 400
 401         if (filter != NULL) {
 402                 sflt_detach_private(filter, 0);
 403         }
 404         else {
 405                 socket->so_filt = NULL;
 406                 result = ENOENT;
 407         }
 408
 409         socket_unlock(socket, 1);
 410
 411         return result;
 412 }
 413
 414
 415 errno_t
 416 sflt_register(
 417         const struct sflt_filter        *filter,
 418         int                                                     domain,
 419         int                                                     type,
 420         int                                                     protocol)
 421 {
 422         struct socket_filter *sock_filt = NULL;
 423         struct socket_filter *match = NULL;
 424         int error = 0;
 425         struct protosw *pr = pffindproto(domain, protocol, type);
 426
 427         if (pr == NULL) return ENOENT;
 428
 429         if (filter->sf_attach == NULL || filter->sf_detach == NULL) return EINVAL;
 430         if (filter->sf_handle == 0) return EINVAL;
 431         if (filter->sf_name == NULL) return EINVAL;
 432
 433         /* Allocate the socket filter */
 434         MALLOC(sock_filt, struct socket_filter*, sizeof(*sock_filt), M_IFADDR, M_WAITOK);
 435         if (sock_filt == NULL) {
 436                 return ENOBUFS;
 437         }
 438
 439         bzero(sock_filt, sizeof(*sock_filt));
 440         sock_filt->sf_filter = *filter;
 441
 442         lck_mtx_lock(sock_filter_lock);
 443         /* Look for an existing entry */
 444         TAILQ_FOREACH(match, &sock_filter_head, sf_global_next) {
 445                 if (match->sf_filter.sf_handle == sock_filt->sf_filter.sf_handle) {
 446                         break;
 447                 }
 448         }
 449
 450         /* Add the entry only if there was no existing entry */
 451         if (match == NULL) {
 452                 TAILQ_INSERT_TAIL(&sock_filter_head, sock_filt, sf_global_next);
 453                 if ((sock_filt->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 454                         TAILQ_INSERT_TAIL(&pr->pr_filter_head, sock_filt, sf_protosw_next);
 455                         sock_filt->sf_proto = pr;
 456                 }
 457         }
 458         lck_mtx_unlock(sock_filter_lock);
 459
 460         if (match != NULL) {
 461                 FREE(sock_filt, M_IFADDR);
 462                 return EEXIST;
 463         }
 464
 465         return error;
 466 }
 467
 468 errno_t
 469 sflt_unregister(
 470         sflt_handle handle)
 471 {
 472         struct socket_filter *filter;
 473         struct socket_filter_entry *entry_head = NULL;
 474         struct socket_filter_entry *next_entry = NULL;
 475
 476         /* Find the entry and remove it from the global and protosw lists */
 477         lck_mtx_lock(sock_filter_lock);
 478         TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 479                 if (filter->sf_filter.sf_handle == handle)
 480                         break;
 481         }
 482
 483         if (filter) {
 484                 TAILQ_REMOVE(&sock_filter_head, filter, sf_global_next);
 485                 if ((filter->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 486                         TAILQ_REMOVE(&filter->sf_proto->pr_filter_head, filter, sf_protosw_next);
 487                 }
 488                 entry_head = filter->sf_entry_head;
 489                 filter->sf_entry_head = NULL;
 490                 filter->sf_flags |= SFF_DETACHING;
 491
 492                 for (next_entry = entry_head; next_entry;
 493                          next_entry = next_entry->sfe_next_onfilter) {
 494                         socket_lock(next_entry->sfe_socket, 1);
 495                         next_entry->sfe_flags |= SFEF_UNREGISTERING;
 496                         socket_unlock(next_entry->sfe_socket, 0);       /* Radar 4201550: prevents the socket from being deleted while being unregistered */
 497                 }
 498         }
 499
 500         lck_mtx_unlock(sock_filter_lock);
 501
 502         if (filter == NULL)
 503                 return ENOENT;
 504
 505         /* We need to detach the filter from any sockets it's attached to */
 506         if (entry_head == 0) {
 507                 if (filter->sf_filter.sf_unregistered)
 508                         filter->sf_filter.sf_unregistered(filter->sf_filter.sf_handle);
 509         } else {
 510                 while (entry_head) {
 511                         next_entry = entry_head->sfe_next_onfilter;
 512                         sflt_detach_private(entry_head, 1);
 513                         entry_head = next_entry;
 514                 }
 515         }
 516
 517         return 0;
 518 }
 519
 520 errno_t
 521 sock_inject_data_in(
 522         socket_t so,
 523         const struct sockaddr* from,
 524         mbuf_t data,
 525         mbuf_t control,
 526         sflt_data_flag_t flags)
 527 {
 528         int error = 0;
 529         if (so == NULL || data == NULL) return EINVAL;
 530
 531         if (flags & sock_data_filt_flag_oob) {
 532                 return ENOTSUP;
 533         }
 534
 535         socket_lock(so, 1);
 536
 537         if (from) {
 538                 if (sbappendaddr(&so->so_rcv, (struct sockaddr*)from, data,
 539                                                  control, NULL))
 540                         sorwakeup(so);
 541                 goto done;
 542         }
 543
 544         if (control) {
 545                 if (sbappendcontrol(&so->so_rcv, data, control, NULL))
 546                         sorwakeup(so);
 547                 goto done;
 548         }
 549
 550         if (flags & sock_data_filt_flag_record) {
 551                 if (control || from) {
 552                         error = EINVAL;
 553                         goto done;
 554                 }
 555                 if (sbappendrecord(&so->so_rcv, (struct mbuf*)data))
 556                         sorwakeup(so);
 557                 goto done;
 558         }
 559
 560         if (sbappend(&so->so_rcv, data))
 561                 sorwakeup(so);
 562 done:
 563         socket_unlock(so, 1);
 564         return error;
 565 }
 566
 567 errno_t
 568 sock_inject_data_out(
 569         socket_t so,
 570         const struct sockaddr* to,
 571         mbuf_t data,
 572         mbuf_t control,
 573         sflt_data_flag_t flags)
 574 {
 575         int     sosendflags = 0;
 576         if (flags & sock_data_filt_flag_oob) sosendflags = MSG_OOB;
 577         return sosend(so, (const struct sockaddr*)to, NULL,
 578                                   data, control, sosendflags);
 579 }
 580
 581 sockopt_dir
 582 sockopt_direction(
 583         sockopt_t       sopt)
 584 {
 585         return (sopt->sopt_dir == SOPT_GET) ? sockopt_get : sockopt_set;
 586 }
 587
 588 int
 589 sockopt_level(
 590         sockopt_t       sopt)
 591 {
 592         return sopt->sopt_level;
 593 }
 594
 595 int
 596 sockopt_name(
 597         sockopt_t       sopt)
 598 {
 599         return sopt->sopt_name;
 600 }
 601
 602 size_t
 603 sockopt_valsize(
 604         sockopt_t       sopt)
 605 {
 606         return sopt->sopt_valsize;
 607 }
 608
 609 errno_t
 610 sockopt_copyin(
 611         sockopt_t       sopt,
 612         void *data,
 613         size_t  len)
 614 {
 615         return sooptcopyin(sopt, data, len, len);
 616 }
 617
 618 errno_t
 619 sockopt_copyout(
 620         sockopt_t       sopt,
 621         void *data,
 622         size_t  len)
 623 {
 624         return sooptcopyout(sopt, data, len);
 625 }