/* * lib/socket.c Netlink Socket * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation version 2.1 * of the License. * * Copyright (c) 2003-2008 Thomas Graf */ /** * @ingroup core * @defgroup socket Socket * @{ */ #include #include #include #include #include #include static uint32_t used_ports_map[32]; static uint32_t generate_local_port(void) { int i, n; uint32_t pid = getpid() & 0x3FFFFF; for (i = 0; i < 32; i++) { if (used_ports_map[i] == 0xFFFFFFFF) continue; for (n = 0; n < 32; n++) { if (1UL & (used_ports_map[i] >> n)) continue; used_ports_map[i] |= (1UL << n); n += (i * 32); /* PID_MAX_LIMIT is currently at 2^22, leaving 10 bit * to, i.e. 1024 unique ports per application. */ return pid + (n << 22); } } /* Out of sockets in our own PID namespace, what to do? FIXME */ return UINT_MAX; } static void release_local_port(uint32_t port) { int nr; if (port == UINT_MAX) return; nr = port >> 22; used_ports_map[nr / 32] &= ~(1 << nr % 32); } /** * @name Allocation * @{ */ static struct nl_sock *__alloc_socket(struct nl_cb *cb) { struct nl_sock *sk; sk = calloc(1, sizeof(*sk)); if (!sk) return NULL; sk->s_fd = -1; sk->s_cb = cb; sk->s_local.nl_family = AF_NETLINK; sk->s_peer.nl_family = AF_NETLINK; sk->s_seq_expect = sk->s_seq_next = time(0); sk->s_local.nl_pid = generate_local_port(); if (sk->s_local.nl_pid == UINT_MAX) { nl_socket_free(sk); return NULL; } return sk; } /** * Allocate new netlink socket * * @return Newly allocated netlink socket or NULL. */ struct nl_sock *nl_socket_alloc(void) { struct nl_cb *cb; cb = nl_cb_alloc(NL_CB_DEFAULT); if (!cb) return NULL; return __alloc_socket(cb); } /** * Allocate new socket with custom callbacks * @arg cb Callback handler * * The reference to the callback handler is taken into account * automatically, it is released again upon calling nl_socket_free(). * *@return Newly allocted socket handle or NULL. */ struct nl_sock *nl_socket_alloc_cb(struct nl_cb *cb) { if (cb == NULL) BUG(); return __alloc_socket(nl_cb_get(cb)); } /** * Free a netlink socket. * @arg sk Netlink socket. */ void nl_socket_free(struct nl_sock *sk) { if (!sk) return; if (sk->s_fd >= 0) close(sk->s_fd); if (!(sk->s_flags & NL_OWN_PORT)) release_local_port(sk->s_local.nl_pid); nl_cb_put(sk->s_cb); free(sk); } /** @} */ /** * @name Sequence Numbers * @{ */ static int noop_seq_check(struct nl_msg *msg, void *arg) { return NL_OK; } /** * Disable sequence number checking. * @arg sk Netlink socket. * * Disables checking of sequence numbers on the netlink socket This is * required to allow messages to be processed which were not requested by * a preceding request message, e.g. netlink events. * * @note This function modifies the NL_CB_SEQ_CHECK configuration in * the callback handle associated with the socket. */ void nl_socket_disable_seq_check(struct nl_sock *sk) { nl_cb_set(sk->s_cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, noop_seq_check, NULL); } /** @} */ /** * Set local port of socket * @arg sk Netlink socket. * @arg port Local port identifier * * Assigns a local port identifier to the socket. If port is 0 * a unique port identifier will be generated automatically. */ void nl_socket_set_local_port(struct nl_sock *sk, uint32_t port) { if (port == 0) { port = generate_local_port(); sk->s_flags &= ~NL_OWN_PORT; } else { if (!(sk->s_flags & NL_OWN_PORT)) release_local_port(sk->s_local.nl_pid); sk->s_flags |= NL_OWN_PORT; } sk->s_local.nl_pid = port; } /** @} */ /** * @name Group Subscriptions * @{ */ /** * Join groups * @arg sk Netlink socket * @arg group Group identifier * * Joins the specified groups using the modern socket option which * is available since kernel version 2.6.14. It allows joining an * almost arbitary number of groups without limitation. The list * of groups has to be terminated by 0 (%NFNLGRP_NONE). * * Make sure to use the correct group definitions as the older * bitmask definitions for nl_join_groups() are likely to still * be present for backward compatibility reasons. * * @return 0 on sucess or a negative error code. */ int nl_socket_add_memberships(struct nl_sock *sk, int group, ...) { int err; va_list ap; if (sk->s_fd == -1) return -NLE_BAD_SOCK; va_start(ap, group); while (group != 0) { if (group < 0) return -NLE_INVAL; err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_ADD_MEMBERSHIP, &group, sizeof(group)); if (err < 0) return -nl_syserr2nlerr(errno); group = va_arg(ap, int); } va_end(ap); return 0; } /** * Leave groups * @arg sk Netlink socket * @arg group Group identifier * * Leaves the specified groups using the modern socket option * which is available since kernel version 2.6.14. The list of groups * has to terminated by 0 (%NFNLGRP_NONE). * * @see nl_socket_add_membership * @return 0 on success or a negative error code. */ int nl_socket_drop_memberships(struct nl_sock *sk, int group, ...) { int err; va_list ap; if (sk->s_fd == -1) return -NLE_BAD_SOCK; va_start(ap, group); while (group != 0) { if (group < 0) return -NLE_INVAL; err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_DROP_MEMBERSHIP, &group, sizeof(group)); if (err < 0) return -nl_syserr2nlerr(errno); group = va_arg(ap, int); } va_end(ap); return 0; } /** @} */ /** * Set file descriptor of socket to non-blocking state * @arg sk Netlink socket. * * @return 0 on success or a negative error code. */ int nl_socket_set_nonblocking(struct nl_sock *sk) { if (sk->s_fd == -1) return -NLE_BAD_SOCK; if (fcntl(sk->s_fd, F_SETFL, O_NONBLOCK) < 0) return -nl_syserr2nlerr(errno); return 0; } /** @} */ /** * @name Utilities * @{ */ /** * Set socket buffer size of netlink socket. * @arg sk Netlink socket. * @arg rxbuf New receive socket buffer size in bytes. * @arg txbuf New transmit socket buffer size in bytes. * * Sets the socket buffer size of a netlink socket to the specified * values \c rxbuf and \c txbuf. Providing a value of \c 0 assumes a * good default value. * * @note It is not required to call this function prior to nl_connect(). * @return 0 on sucess or a negative error code. */ int nl_socket_set_buffer_size(struct nl_sock *sk, int rxbuf, int txbuf) { int err; if (rxbuf <= 0) rxbuf = 32768; if (txbuf <= 0) txbuf = 32768; if (sk->s_fd == -1) return -NLE_BAD_SOCK; err = setsockopt(sk->s_fd, SOL_SOCKET, SO_SNDBUF, &txbuf, sizeof(txbuf)); if (err < 0) return -nl_syserr2nlerr(errno); err = setsockopt(sk->s_fd, SOL_SOCKET, SO_RCVBUF, &rxbuf, sizeof(rxbuf)); if (err < 0) return -nl_syserr2nlerr(errno); sk->s_flags |= NL_SOCK_BUFSIZE_SET; return 0; } /** * Enable/disable credential passing on netlink socket. * @arg sk Netlink socket. * @arg state New state (0 - disabled, 1 - enabled) * * @return 0 on success or a negative error code */ int nl_socket_set_passcred(struct nl_sock *sk, int state) { int err; if (sk->s_fd == -1) return -NLE_BAD_SOCK; err = setsockopt(sk->s_fd, SOL_SOCKET, SO_PASSCRED, &state, sizeof(state)); if (err < 0) return -nl_syserr2nlerr(errno); if (state) sk->s_flags |= NL_SOCK_PASSCRED; else sk->s_flags &= ~NL_SOCK_PASSCRED; return 0; } /** * Enable/disable receival of additional packet information * @arg sk Netlink socket. * @arg state New state (0 - disabled, 1 - enabled) * * @return 0 on success or a negative error code */ int nl_socket_recv_pktinfo(struct nl_sock *sk, int state) { int err; if (sk->s_fd == -1) return -NLE_BAD_SOCK; err = setsockopt(sk->s_fd, SOL_NETLINK, NETLINK_PKTINFO, &state, sizeof(state)); if (err < 0) return -nl_syserr2nlerr(errno); return 0; } /** @} */ /** @} */ 0' href='#n150'>150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633