1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2021 Ng Peng Nam Sean 5 * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org> 6 * Copyright (c) 2023 Gleb Smirnoff <glebius@FreeBSD.org> 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * This file contains socket and protocol bindings for netlink. 32 */ 33 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/malloc.h> 37 #include <sys/lock.h> 38 #include <sys/rmlock.h> 39 #include <sys/domain.h> 40 #include <sys/jail.h> 41 #include <sys/mbuf.h> 42 #include <sys/osd.h> 43 #include <sys/protosw.h> 44 #include <sys/proc.h> 45 #include <sys/ck.h> 46 #include <sys/socket.h> 47 #include <sys/socketvar.h> 48 #include <sys/sysent.h> 49 #include <sys/syslog.h> 50 #include <sys/priv.h> 51 #include <sys/uio.h> 52 53 #include <netlink/netlink.h> 54 #include <netlink/netlink_ctl.h> 55 #include <netlink/netlink_var.h> 56 57 #define DEBUG_MOD_NAME nl_domain 58 #define DEBUG_MAX_LEVEL LOG_DEBUG3 59 #include <netlink/netlink_debug.h> 60 _DECLARE_DEBUG(LOG_INFO); 61 62 _Static_assert((NLP_MAX_GROUPS % 64) == 0, 63 "NLP_MAX_GROUPS has to be multiple of 64"); 64 _Static_assert(NLP_MAX_GROUPS >= 64, 65 "NLP_MAX_GROUPS has to be at least 64"); 66 67 #define NLCTL_TRACKER struct rm_priotracker nl_tracker 68 #define NLCTL_RLOCK(_ctl) rm_rlock(&((_ctl)->ctl_lock), &nl_tracker) 69 #define NLCTL_RUNLOCK(_ctl) rm_runlock(&((_ctl)->ctl_lock), &nl_tracker) 70 71 #define NLCTL_WLOCK(_ctl) rm_wlock(&((_ctl)->ctl_lock)) 72 #define NLCTL_WUNLOCK(_ctl) rm_wunlock(&((_ctl)->ctl_lock)) 73 74 static u_long nl_sendspace = NLSNDQ; 75 SYSCTL_ULONG(_net_netlink, OID_AUTO, sendspace, CTLFLAG_RW, &nl_sendspace, 0, 76 "Default netlink socket send space"); 77 78 static u_long nl_recvspace = NLSNDQ; 79 SYSCTL_ULONG(_net_netlink, OID_AUTO, recvspace, CTLFLAG_RW, &nl_recvspace, 0, 80 "Default netlink socket receive space"); 81 82 extern u_long sb_max_adj; 83 static u_long nl_maxsockbuf = 512 * 1024 * 1024; /* 512M, XXX: init based on physmem */ 84 static int sysctl_handle_nl_maxsockbuf(SYSCTL_HANDLER_ARGS); 85 SYSCTL_OID(_net_netlink, OID_AUTO, nl_maxsockbuf, 86 CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_MPSAFE, &nl_maxsockbuf, 0, 87 sysctl_handle_nl_maxsockbuf, "LU", 88 "Maximum Netlink socket buffer size"); 89 90 91 static unsigned int osd_slot_id = 0; 92 93 void 94 nl_osd_register(void) 95 { 96 osd_slot_id = osd_register(OSD_THREAD, NULL, NULL); 97 } 98 99 void 100 nl_osd_unregister(void) 101 { 102 osd_deregister(OSD_THREAD, osd_slot_id); 103 } 104 105 struct nlpcb * 106 _nl_get_thread_nlp(struct thread *td) 107 { 108 return (osd_get(OSD_THREAD, &td->td_osd, osd_slot_id)); 109 } 110 111 void 112 nl_set_thread_nlp(struct thread *td, struct nlpcb *nlp) 113 { 114 NLP_LOG(LOG_DEBUG2, nlp, "Set thread %p nlp to %p (slot %u)", td, nlp, osd_slot_id); 115 if (osd_set(OSD_THREAD, &td->td_osd, osd_slot_id, nlp) == 0) 116 return; 117 /* Failed, need to realloc */ 118 void **rsv = osd_reserve(osd_slot_id); 119 osd_set_reserved(OSD_THREAD, &td->td_osd, osd_slot_id, rsv, nlp); 120 } 121 122 /* 123 * Looks up a nlpcb struct based on the @portid. Need to claim nlsock_mtx. 124 * Returns nlpcb pointer if present else NULL 125 */ 126 static struct nlpcb * 127 nl_port_lookup(uint32_t port_id) 128 { 129 struct nlpcb *nlp; 130 131 CK_LIST_FOREACH(nlp, &V_nl_ctl->ctl_port_head, nl_port_next) { 132 if (nlp->nl_port == port_id) 133 return (nlp); 134 } 135 return (NULL); 136 } 137 138 static void 139 nl_add_group_locked(struct nlpcb *nlp, unsigned int group_id) 140 { 141 MPASS(group_id <= NLP_MAX_GROUPS); 142 --group_id; 143 144 /* TODO: add family handler callback */ 145 if (!nlp_unconstrained_vnet(nlp)) 146 return; 147 148 BIT_SET(NLP_MAX_GROUPS, group_id, &nlp->nl_groups); 149 } 150 151 static void 152 nl_del_group_locked(struct nlpcb *nlp, unsigned int group_id) 153 { 154 MPASS(group_id <= NLP_MAX_GROUPS); 155 --group_id; 156 157 BIT_CLR(NLP_MAX_GROUPS, group_id, &nlp->nl_groups); 158 } 159 160 static bool 161 nl_isset_group_locked(struct nlpcb *nlp, unsigned int group_id) 162 { 163 MPASS(group_id <= NLP_MAX_GROUPS); 164 --group_id; 165 166 return (BIT_ISSET(NLP_MAX_GROUPS, group_id, &nlp->nl_groups)); 167 } 168 169 static uint32_t 170 nl_get_groups_compat(struct nlpcb *nlp) 171 { 172 uint32_t groups_mask = 0; 173 174 for (int i = 0; i < 32; i++) { 175 if (nl_isset_group_locked(nlp, i + 1)) 176 groups_mask |= (1 << i); 177 } 178 179 return (groups_mask); 180 } 181 182 static struct nl_buf * 183 nl_buf_copy(struct nl_buf *nb) 184 { 185 struct nl_buf *copy; 186 187 copy = nl_buf_alloc(nb->buflen, M_NOWAIT); 188 if (__predict_false(copy == NULL)) 189 return (NULL); 190 memcpy(copy, nb, sizeof(*nb) + nb->buflen); 191 192 return (copy); 193 } 194 195 /* 196 * Broadcasts in the writer's buffer. 197 */ 198 bool 199 nl_send_group(struct nl_writer *nw) 200 { 201 struct nl_buf *nb = nw->buf; 202 struct nlpcb *nlp_last = NULL; 203 struct nlpcb *nlp; 204 NLCTL_TRACKER; 205 206 IF_DEBUG_LEVEL(LOG_DEBUG2) { 207 struct nlmsghdr *hdr = (struct nlmsghdr *)nb->data; 208 NL_LOG(LOG_DEBUG2, "MCAST len %u msg type %d len %u to group %d/%d", 209 nb->datalen, hdr->nlmsg_type, hdr->nlmsg_len, 210 nw->group.proto, nw->group.id); 211 } 212 213 nw->buf = NULL; 214 215 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 216 if (__predict_false(ctl == NULL)) { 217 /* 218 * Can be the case when notification is sent within VNET 219 * which doesn't have any netlink sockets. 220 */ 221 nl_buf_free(nb); 222 return (false); 223 } 224 225 NLCTL_RLOCK(ctl); 226 227 CK_LIST_FOREACH(nlp, &ctl->ctl_pcb_head, nl_next) { 228 if ((nw->group.priv == 0 || priv_check_cred( 229 nlp->nl_socket->so_cred, nw->group.priv) == 0) && 230 nlp->nl_proto == nw->group.proto && 231 nl_isset_group_locked(nlp, nw->group.id)) { 232 if (nlp_last != NULL) { 233 struct nl_buf *copy; 234 235 copy = nl_buf_copy(nb); 236 if (copy != NULL) { 237 nw->buf = copy; 238 (void)nl_send(nw, nlp_last); 239 } else { 240 NLP_LOCK(nlp_last); 241 if (nlp_last->nl_socket != NULL) 242 sorwakeup(nlp_last->nl_socket); 243 NLP_UNLOCK(nlp_last); 244 } 245 } 246 nlp_last = nlp; 247 } 248 } 249 if (nlp_last != NULL) { 250 nw->buf = nb; 251 (void)nl_send(nw, nlp_last); 252 } else 253 nl_buf_free(nb); 254 255 NLCTL_RUNLOCK(ctl); 256 257 return (true); 258 } 259 260 bool 261 nl_has_listeners(uint16_t netlink_family, uint32_t groups_mask) 262 { 263 return (V_nl_ctl != NULL); 264 } 265 266 static uint32_t 267 nl_find_port(void) 268 { 269 /* 270 * app can open multiple netlink sockets. 271 * Start with current pid, if already taken, 272 * try random numbers in 65k..256k+65k space, 273 * avoiding clash with pids. 274 */ 275 if (nl_port_lookup(curproc->p_pid) == NULL) 276 return (curproc->p_pid); 277 for (int i = 0; i < 16; i++) { 278 uint32_t nl_port = (arc4random() % 65536) + 65536 * 4; 279 if (nl_port_lookup(nl_port) == 0) 280 return (nl_port); 281 NL_LOG(LOG_DEBUG3, "tried %u\n", nl_port); 282 } 283 return (curproc->p_pid); 284 } 285 286 static int 287 nl_bind_locked(struct nlpcb *nlp, struct sockaddr_nl *snl) 288 { 289 if (nlp->nl_bound) { 290 if (nlp->nl_port != snl->nl_pid) { 291 NL_LOG(LOG_DEBUG, 292 "bind() failed: program pid %d " 293 "is different from provided pid %d", 294 nlp->nl_port, snl->nl_pid); 295 return (EINVAL); // XXX: better error 296 } 297 } else { 298 if (snl->nl_pid == 0) 299 snl->nl_pid = nl_find_port(); 300 if (nl_port_lookup(snl->nl_pid) != NULL) 301 return (EADDRINUSE); 302 nlp->nl_port = snl->nl_pid; 303 nlp->nl_bound = true; 304 CK_LIST_INSERT_HEAD(&V_nl_ctl->ctl_port_head, nlp, nl_port_next); 305 } 306 for (int i = 0; i < 32; i++) { 307 if (snl->nl_groups & ((uint32_t)1 << i)) 308 nl_add_group_locked(nlp, i + 1); 309 else 310 nl_del_group_locked(nlp, i + 1); 311 } 312 313 return (0); 314 } 315 316 static int 317 nl_pru_attach(struct socket *so, int proto, struct thread *td) 318 { 319 struct nlpcb *nlp; 320 int error; 321 322 if (__predict_false(netlink_unloading != 0)) 323 return (EAFNOSUPPORT); 324 325 error = nl_verify_proto(proto); 326 if (error != 0) 327 return (error); 328 329 bool is_linux = SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX; 330 NL_LOG(LOG_DEBUG2, "socket %p, %sPID %d: attaching socket to %s", 331 so, is_linux ? "(linux) " : "", curproc->p_pid, 332 nl_get_proto_name(proto)); 333 334 /* Create per-VNET state on first socket init */ 335 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 336 if (ctl == NULL) 337 ctl = vnet_nl_ctl_init(); 338 KASSERT(V_nl_ctl != NULL, ("nl_attach: vnet_sock_init() failed")); 339 340 MPASS(sotonlpcb(so) == NULL); 341 342 nlp = malloc(sizeof(struct nlpcb), M_PCB, M_WAITOK | M_ZERO); 343 error = soreserve(so, nl_sendspace, nl_recvspace); 344 if (error != 0) { 345 free(nlp, M_PCB); 346 return (error); 347 } 348 TAILQ_INIT(&so->so_rcv.nl_queue); 349 TAILQ_INIT(&so->so_snd.nl_queue); 350 so->so_pcb = nlp; 351 nlp->nl_socket = so; 352 /* Copy so_cred to avoid having socket_var.h in every header */ 353 nlp->nl_cred = so->so_cred; 354 nlp->nl_proto = proto; 355 nlp->nl_process_id = curproc->p_pid; 356 nlp->nl_linux = is_linux; 357 nlp->nl_unconstrained_vnet = !jailed_without_vnet(so->so_cred); 358 nlp->nl_need_thread_setup = true; 359 NLP_LOCK_INIT(nlp); 360 refcount_init(&nlp->nl_refcount, 1); 361 362 nlp->nl_taskqueue = taskqueue_create("netlink_socket", M_WAITOK, 363 taskqueue_thread_enqueue, &nlp->nl_taskqueue); 364 TASK_INIT(&nlp->nl_task, 0, nl_taskqueue_handler, nlp); 365 taskqueue_start_threads(&nlp->nl_taskqueue, 1, PWAIT, 366 "netlink_socket (PID %u)", nlp->nl_process_id); 367 368 NLCTL_WLOCK(ctl); 369 /* XXX: check ctl is still alive */ 370 CK_LIST_INSERT_HEAD(&ctl->ctl_pcb_head, nlp, nl_next); 371 NLCTL_WUNLOCK(ctl); 372 373 soisconnected(so); 374 375 return (0); 376 } 377 378 static int 379 nl_pru_bind(struct socket *so, struct sockaddr *sa, struct thread *td) 380 { 381 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 382 struct nlpcb *nlp = sotonlpcb(so); 383 struct sockaddr_nl *snl = (struct sockaddr_nl *)sa; 384 int error; 385 386 NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid); 387 if (snl->nl_len != sizeof(*snl)) { 388 NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so); 389 return (EINVAL); 390 } 391 392 393 NLCTL_WLOCK(ctl); 394 NLP_LOCK(nlp); 395 error = nl_bind_locked(nlp, snl); 396 NLP_UNLOCK(nlp); 397 NLCTL_WUNLOCK(ctl); 398 NL_LOG(LOG_DEBUG2, "socket %p, bind() to %u, groups %u, error %d", so, 399 snl->nl_pid, snl->nl_groups, error); 400 401 return (error); 402 } 403 404 405 static int 406 nl_assign_port(struct nlpcb *nlp, uint32_t port_id) 407 { 408 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 409 struct sockaddr_nl snl = { 410 .nl_pid = port_id, 411 }; 412 int error; 413 414 NLCTL_WLOCK(ctl); 415 NLP_LOCK(nlp); 416 snl.nl_groups = nl_get_groups_compat(nlp); 417 error = nl_bind_locked(nlp, &snl); 418 NLP_UNLOCK(nlp); 419 NLCTL_WUNLOCK(ctl); 420 421 NL_LOG(LOG_DEBUG3, "socket %p, port assign: %d, error: %d", nlp->nl_socket, port_id, error); 422 return (error); 423 } 424 425 /* 426 * nl_autobind_port binds a unused portid to @nlp 427 * @nlp: pcb data for the netlink socket 428 * @candidate_id: first id to consider 429 */ 430 static int 431 nl_autobind_port(struct nlpcb *nlp, uint32_t candidate_id) 432 { 433 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 434 uint32_t port_id = candidate_id; 435 NLCTL_TRACKER; 436 bool exist; 437 int error = EADDRINUSE; 438 439 for (int i = 0; i < 10; i++) { 440 NL_LOG(LOG_DEBUG3, "socket %p, trying to assign port %d", nlp->nl_socket, port_id); 441 NLCTL_RLOCK(ctl); 442 exist = nl_port_lookup(port_id) != 0; 443 NLCTL_RUNLOCK(ctl); 444 if (!exist) { 445 error = nl_assign_port(nlp, port_id); 446 if (error != EADDRINUSE) 447 break; 448 } 449 port_id++; 450 } 451 NL_LOG(LOG_DEBUG3, "socket %p, autobind to %d, error: %d", nlp->nl_socket, port_id, error); 452 return (error); 453 } 454 455 static int 456 nl_pru_connect(struct socket *so, struct sockaddr *sa, struct thread *td) 457 { 458 struct sockaddr_nl *snl = (struct sockaddr_nl *)sa; 459 struct nlpcb *nlp; 460 461 NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid); 462 if (snl->nl_len != sizeof(*snl)) { 463 NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so); 464 return (EINVAL); 465 } 466 467 nlp = sotonlpcb(so); 468 if (!nlp->nl_bound) { 469 int error = nl_autobind_port(nlp, td->td_proc->p_pid); 470 if (error != 0) { 471 NL_LOG(LOG_DEBUG, "socket %p, nl_autobind() failed: %d", so, error); 472 return (error); 473 } 474 } 475 /* XXX: Handle socket flags & multicast */ 476 soisconnected(so); 477 478 NL_LOG(LOG_DEBUG2, "socket %p, connect to %u", so, snl->nl_pid); 479 480 return (0); 481 } 482 483 static void 484 destroy_nlpcb_epoch(epoch_context_t ctx) 485 { 486 struct nlpcb *nlp; 487 488 nlp = __containerof(ctx, struct nlpcb, nl_epoch_ctx); 489 490 NLP_LOCK_DESTROY(nlp); 491 free(nlp, M_PCB); 492 } 493 494 static void 495 nl_close(struct socket *so) 496 { 497 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 498 MPASS(sotonlpcb(so) != NULL); 499 struct nlpcb *nlp; 500 struct nl_buf *nb; 501 502 NL_LOG(LOG_DEBUG2, "detaching socket %p, PID %d", so, curproc->p_pid); 503 nlp = sotonlpcb(so); 504 505 /* Mark as inactive so no new work can be enqueued */ 506 NLP_LOCK(nlp); 507 bool was_bound = nlp->nl_bound; 508 NLP_UNLOCK(nlp); 509 510 /* Wait till all scheduled work has been completed */ 511 taskqueue_drain_all(nlp->nl_taskqueue); 512 taskqueue_free(nlp->nl_taskqueue); 513 514 NLCTL_WLOCK(ctl); 515 NLP_LOCK(nlp); 516 if (was_bound) { 517 CK_LIST_REMOVE(nlp, nl_port_next); 518 NL_LOG(LOG_DEBUG3, "socket %p, unlinking bound pid %u", so, nlp->nl_port); 519 } 520 CK_LIST_REMOVE(nlp, nl_next); 521 nlp->nl_socket = NULL; 522 NLP_UNLOCK(nlp); 523 NLCTL_WUNLOCK(ctl); 524 525 so->so_pcb = NULL; 526 527 while ((nb = TAILQ_FIRST(&so->so_snd.nl_queue)) != NULL) { 528 TAILQ_REMOVE(&so->so_snd.nl_queue, nb, tailq); 529 nl_buf_free(nb); 530 } 531 while ((nb = TAILQ_FIRST(&so->so_rcv.nl_queue)) != NULL) { 532 TAILQ_REMOVE(&so->so_rcv.nl_queue, nb, tailq); 533 nl_buf_free(nb); 534 } 535 536 NL_LOG(LOG_DEBUG3, "socket %p, detached", so); 537 538 /* XXX: is delayed free needed? */ 539 NET_EPOCH_CALL(destroy_nlpcb_epoch, &nlp->nl_epoch_ctx); 540 } 541 542 static int 543 nl_pru_disconnect(struct socket *so) 544 { 545 NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid); 546 MPASS(sotonlpcb(so) != NULL); 547 return (ENOTCONN); 548 } 549 550 static int 551 nl_sockaddr(struct socket *so, struct sockaddr *sa) 552 { 553 554 *(struct sockaddr_nl *)sa = (struct sockaddr_nl ){ 555 /* TODO: set other fields */ 556 .nl_len = sizeof(struct sockaddr_nl), 557 .nl_family = AF_NETLINK, 558 .nl_pid = sotonlpcb(so)->nl_port, 559 }; 560 561 return (0); 562 } 563 564 static int 565 nl_sosend(struct socket *so, struct sockaddr *addr, struct uio *uio, 566 struct mbuf *m, struct mbuf *control, int flags, struct thread *td) 567 { 568 struct nlpcb *nlp = sotonlpcb(so); 569 struct sockbuf *sb = &so->so_snd; 570 struct nl_buf *nb; 571 size_t len; 572 int error; 573 574 MPASS(m == NULL && uio != NULL); 575 576 NL_LOG(LOG_DEBUG2, "sending message to kernel"); 577 578 if (__predict_false(control != NULL)) { 579 m_freem(control); 580 return (EINVAL); 581 } 582 583 if (__predict_false(flags & MSG_OOB)) /* XXXGL: or just ignore? */ 584 return (EOPNOTSUPP); 585 586 if (__predict_false(uio->uio_resid < sizeof(struct nlmsghdr))) 587 return (ENOBUFS); /* XXXGL: any better error? */ 588 589 NL_LOG(LOG_DEBUG3, "sending message to kernel async processing"); 590 591 error = SOCK_IO_SEND_LOCK(so, SBLOCKWAIT(flags)); 592 if (error) 593 return (error); 594 595 len = roundup2(uio->uio_resid, 8) + SCRATCH_BUFFER_SIZE; 596 if (nlp->nl_linux) 597 len += roundup2(uio->uio_resid, 8); 598 nb = nl_buf_alloc(len, M_WAITOK); 599 nb->datalen = uio->uio_resid; 600 error = uiomove(&nb->data[0], uio->uio_resid, uio); 601 if (__predict_false(error)) 602 goto out; 603 604 SOCK_SENDBUF_LOCK(so); 605 restart: 606 if (sb->sb_hiwat - sb->sb_ccc >= nb->datalen) { 607 TAILQ_INSERT_TAIL(&sb->nl_queue, nb, tailq); 608 sb->sb_acc += nb->datalen; 609 sb->sb_ccc += nb->datalen; 610 nb = NULL; 611 } else if ((so->so_state & SS_NBIO) || 612 (flags & (MSG_NBIO | MSG_DONTWAIT)) != 0) { 613 SOCK_SENDBUF_UNLOCK(so); 614 error = EWOULDBLOCK; 615 goto out; 616 } else { 617 if ((error = sbwait(so, SO_SND)) != 0) { 618 SOCK_SENDBUF_UNLOCK(so); 619 goto out; 620 } else 621 goto restart; 622 } 623 SOCK_SENDBUF_UNLOCK(so); 624 625 if (nb == NULL) { 626 NL_LOG(LOG_DEBUG3, "enqueue %u bytes", nb->datalen); 627 NLP_LOCK(nlp); 628 nl_schedule_taskqueue(nlp); 629 NLP_UNLOCK(nlp); 630 } 631 632 out: 633 SOCK_IO_SEND_UNLOCK(so); 634 if (nb != NULL) 635 nl_buf_free(nb); 636 return (error); 637 } 638 639 /* Create control data for recvmsg(2) on Netlink socket. */ 640 static struct mbuf * 641 nl_createcontrol(struct nlpcb *nlp) 642 { 643 struct { 644 struct nlattr nla; 645 uint32_t val; 646 } data[] = { 647 { 648 .nla.nla_len = sizeof(struct nlattr) + sizeof(uint32_t), 649 .nla.nla_type = NLMSGINFO_ATTR_PROCESS_ID, 650 .val = nlp->nl_process_id, 651 }, 652 { 653 .nla.nla_len = sizeof(struct nlattr) + sizeof(uint32_t), 654 .nla.nla_type = NLMSGINFO_ATTR_PORT_ID, 655 .val = nlp->nl_port, 656 }, 657 }; 658 659 return (sbcreatecontrol(data, sizeof(data), NETLINK_MSG_INFO, 660 SOL_NETLINK, M_WAITOK)); 661 } 662 663 static int 664 nl_soreceive(struct socket *so, struct sockaddr **psa, struct uio *uio, 665 struct mbuf **mp, struct mbuf **controlp, int *flagsp) 666 { 667 static const struct sockaddr_nl nl_empty_src = { 668 .nl_len = sizeof(struct sockaddr_nl), 669 .nl_family = PF_NETLINK, 670 .nl_pid = 0 /* comes from the kernel */ 671 }; 672 struct sockbuf *sb = &so->so_rcv; 673 struct nlpcb *nlp = sotonlpcb(so); 674 struct nl_buf *first, *last, *nb, *next; 675 struct nlmsghdr *hdr; 676 int flags, error; 677 u_int len, overflow, partoff, partlen, msgrcv, datalen; 678 bool nonblock, trunc, peek; 679 680 MPASS(mp == NULL && uio != NULL); 681 682 NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid); 683 684 if (psa != NULL) 685 *psa = sodupsockaddr((const struct sockaddr *)&nl_empty_src, 686 M_WAITOK); 687 688 if (controlp != NULL && (nlp->nl_flags & NLF_MSG_INFO)) 689 *controlp = nl_createcontrol(nlp); 690 691 flags = flagsp != NULL ? *flagsp & ~MSG_TRUNC : 0; 692 trunc = flagsp != NULL ? *flagsp & MSG_TRUNC : false; 693 nonblock = (so->so_state & SS_NBIO) || 694 (flags & (MSG_DONTWAIT | MSG_NBIO)); 695 peek = flags & MSG_PEEK; 696 697 error = SOCK_IO_RECV_LOCK(so, SBLOCKWAIT(flags)); 698 if (__predict_false(error)) 699 return (error); 700 701 len = 0; 702 overflow = 0; 703 msgrcv = 0; 704 datalen = 0; 705 706 SOCK_RECVBUF_LOCK(so); 707 while ((first = TAILQ_FIRST(&sb->nl_queue)) == NULL) { 708 if (nonblock) { 709 SOCK_RECVBUF_UNLOCK(so); 710 SOCK_IO_RECV_UNLOCK(so); 711 return (EWOULDBLOCK); 712 } 713 error = sbwait(so, SO_RCV); 714 if (error) { 715 SOCK_RECVBUF_UNLOCK(so); 716 SOCK_IO_RECV_UNLOCK(so); 717 return (error); 718 } 719 } 720 721 /* 722 * Netlink socket buffer consists of a queue of nl_bufs, but for the 723 * userland there should be no boundaries. However, there are Netlink 724 * messages, that shouldn't be split. Internal invariant is that a 725 * message never spans two nl_bufs. 726 * If a large userland buffer is provided, we would traverse the queue 727 * until either queue end is reached or the buffer is fulfilled. If 728 * an application provides a buffer that isn't able to fit a single 729 * message, we would truncate it and lose its tail. This is the only 730 * condition where we would lose data. If buffer is able to fit at 731 * least one message, we would return it and won't truncate the next. 732 * 733 * We use same code for normal and MSG_PEEK case. At first queue pass 734 * we scan nl_bufs and count lenght. In case we can read entire buffer 735 * at one write everything is trivial. In case we can not, we save 736 * pointer to the last (or partial) nl_buf and in the !peek case we 737 * split the queue into two pieces. We can safely drop the queue lock, 738 * as kernel would only append nl_bufs to the end of the queue, and 739 * we are the exclusive owner of queue beginning due to sleepable lock. 740 * At the second pass we copy data out and in !peek case free nl_bufs. 741 */ 742 TAILQ_FOREACH(nb, &sb->nl_queue, tailq) { 743 u_int offset; 744 745 MPASS(nb->offset < nb->datalen); 746 offset = nb->offset; 747 while (offset < nb->datalen) { 748 hdr = (struct nlmsghdr *)&nb->data[offset]; 749 MPASS(nb->offset + hdr->nlmsg_len <= nb->datalen); 750 if (uio->uio_resid < len + hdr->nlmsg_len) { 751 overflow = len + hdr->nlmsg_len - 752 uio->uio_resid; 753 partoff = nb->offset; 754 if (offset > partoff) { 755 partlen = offset - partoff; 756 if (!peek) { 757 nb->offset = offset; 758 datalen += partlen; 759 } 760 } else if (len == 0 && uio->uio_resid > 0) { 761 flags |= MSG_TRUNC; 762 partlen = uio->uio_resid; 763 if (peek) 764 goto nospace; 765 datalen += hdr->nlmsg_len; 766 if (nb->offset + hdr->nlmsg_len == 767 nb->datalen) { 768 /* 769 * Avoid leaving empty nb. 770 * Process last nb normally. 771 * Trust uiomove() to care 772 * about negative uio_resid. 773 */ 774 nb = TAILQ_NEXT(nb, tailq); 775 overflow = 0; 776 partlen = 0; 777 } else 778 nb->offset += hdr->nlmsg_len; 779 msgrcv++; 780 } else 781 partlen = 0; 782 goto nospace; 783 } 784 len += hdr->nlmsg_len; 785 offset += hdr->nlmsg_len; 786 MPASS(offset <= nb->buflen); 787 msgrcv++; 788 } 789 MPASS(offset == nb->datalen); 790 datalen += nb->datalen - nb->offset; 791 } 792 nospace: 793 last = nb; 794 if (!peek) { 795 if (last == NULL) 796 TAILQ_INIT(&sb->nl_queue); 797 else { 798 /* XXXGL: create TAILQ_SPLIT */ 799 TAILQ_FIRST(&sb->nl_queue) = last; 800 last->tailq.tqe_prev = &TAILQ_FIRST(&sb->nl_queue); 801 } 802 MPASS(sb->sb_acc >= datalen); 803 sb->sb_acc -= datalen; 804 sb->sb_ccc -= datalen; 805 } 806 SOCK_RECVBUF_UNLOCK(so); 807 808 for (nb = first; nb != last; nb = next) { 809 next = TAILQ_NEXT(nb, tailq); 810 if (__predict_true(error == 0)) 811 error = uiomove(&nb->data[nb->offset], 812 (int)(nb->datalen - nb->offset), uio); 813 if (!peek) 814 nl_buf_free(nb); 815 } 816 if (last != NULL && partlen > 0 && __predict_true(error == 0)) 817 error = uiomove(&nb->data[partoff], (int)partlen, uio); 818 819 if (trunc && overflow > 0) { 820 uio->uio_resid -= overflow; 821 MPASS(uio->uio_resid < 0); 822 } else 823 MPASS(uio->uio_resid >= 0); 824 825 if (uio->uio_td) 826 uio->uio_td->td_ru.ru_msgrcv += msgrcv; 827 828 if (flagsp != NULL) 829 *flagsp |= flags; 830 831 SOCK_IO_RECV_UNLOCK(so); 832 833 nl_on_transmit(sotonlpcb(so)); 834 835 return (error); 836 } 837 838 static int 839 nl_getoptflag(int sopt_name) 840 { 841 switch (sopt_name) { 842 case NETLINK_CAP_ACK: 843 return (NLF_CAP_ACK); 844 case NETLINK_EXT_ACK: 845 return (NLF_EXT_ACK); 846 case NETLINK_GET_STRICT_CHK: 847 return (NLF_STRICT); 848 case NETLINK_MSG_INFO: 849 return (NLF_MSG_INFO); 850 } 851 852 return (0); 853 } 854 855 static int 856 nl_ctloutput(struct socket *so, struct sockopt *sopt) 857 { 858 struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl); 859 struct nlpcb *nlp = sotonlpcb(so); 860 uint32_t flag; 861 int optval, error = 0; 862 NLCTL_TRACKER; 863 864 NL_LOG(LOG_DEBUG2, "%ssockopt(%p, %d)", (sopt->sopt_dir) ? "set" : "get", 865 so, sopt->sopt_name); 866 867 switch (sopt->sopt_dir) { 868 case SOPT_SET: 869 switch (sopt->sopt_name) { 870 case NETLINK_ADD_MEMBERSHIP: 871 case NETLINK_DROP_MEMBERSHIP: 872 error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval)); 873 if (error != 0) 874 break; 875 if (optval <= 0 || optval >= NLP_MAX_GROUPS) { 876 error = ERANGE; 877 break; 878 } 879 NL_LOG(LOG_DEBUG2, "ADD/DEL group %d", (uint32_t)optval); 880 881 NLCTL_WLOCK(ctl); 882 if (sopt->sopt_name == NETLINK_ADD_MEMBERSHIP) 883 nl_add_group_locked(nlp, optval); 884 else 885 nl_del_group_locked(nlp, optval); 886 NLCTL_WUNLOCK(ctl); 887 break; 888 case NETLINK_CAP_ACK: 889 case NETLINK_EXT_ACK: 890 case NETLINK_GET_STRICT_CHK: 891 case NETLINK_MSG_INFO: 892 error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval)); 893 if (error != 0) 894 break; 895 896 flag = nl_getoptflag(sopt->sopt_name); 897 898 if ((flag == NLF_MSG_INFO) && nlp->nl_linux) { 899 error = EINVAL; 900 break; 901 } 902 903 NLCTL_WLOCK(ctl); 904 if (optval != 0) 905 nlp->nl_flags |= flag; 906 else 907 nlp->nl_flags &= ~flag; 908 NLCTL_WUNLOCK(ctl); 909 break; 910 default: 911 error = ENOPROTOOPT; 912 } 913 break; 914 case SOPT_GET: 915 switch (sopt->sopt_name) { 916 case NETLINK_LIST_MEMBERSHIPS: 917 NLCTL_RLOCK(ctl); 918 optval = nl_get_groups_compat(nlp); 919 NLCTL_RUNLOCK(ctl); 920 error = sooptcopyout(sopt, &optval, sizeof(optval)); 921 break; 922 case NETLINK_CAP_ACK: 923 case NETLINK_EXT_ACK: 924 case NETLINK_GET_STRICT_CHK: 925 case NETLINK_MSG_INFO: 926 NLCTL_RLOCK(ctl); 927 optval = (nlp->nl_flags & nl_getoptflag(sopt->sopt_name)) != 0; 928 NLCTL_RUNLOCK(ctl); 929 error = sooptcopyout(sopt, &optval, sizeof(optval)); 930 break; 931 default: 932 error = ENOPROTOOPT; 933 } 934 break; 935 default: 936 error = ENOPROTOOPT; 937 } 938 939 return (error); 940 } 941 942 static int 943 sysctl_handle_nl_maxsockbuf(SYSCTL_HANDLER_ARGS) 944 { 945 int error = 0; 946 u_long tmp_maxsockbuf = nl_maxsockbuf; 947 948 error = sysctl_handle_long(oidp, &tmp_maxsockbuf, arg2, req); 949 if (error || !req->newptr) 950 return (error); 951 if (tmp_maxsockbuf < MSIZE + MCLBYTES) 952 return (EINVAL); 953 nl_maxsockbuf = tmp_maxsockbuf; 954 955 return (0); 956 } 957 958 static int 959 nl_setsbopt(struct socket *so, struct sockopt *sopt) 960 { 961 int error, optval; 962 bool result; 963 964 if (sopt->sopt_name != SO_RCVBUF) 965 return (sbsetopt(so, sopt)); 966 967 /* Allow to override max buffer size in certain conditions */ 968 969 error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval); 970 if (error != 0) 971 return (error); 972 NL_LOG(LOG_DEBUG2, "socket %p, PID %d, SO_RCVBUF=%d", so, curproc->p_pid, optval); 973 if (optval > sb_max_adj) { 974 if (priv_check(curthread, PRIV_NET_ROUTE) != 0) 975 return (EPERM); 976 } 977 978 SOCK_RECVBUF_LOCK(so); 979 result = sbreserve_locked_limit(so, SO_RCV, optval, nl_maxsockbuf, curthread); 980 SOCK_RECVBUF_UNLOCK(so); 981 982 return (result ? 0 : ENOBUFS); 983 } 984 985 #define NETLINK_PROTOSW \ 986 .pr_flags = PR_ATOMIC | PR_ADDR | PR_SOCKBUF, \ 987 .pr_ctloutput = nl_ctloutput, \ 988 .pr_setsbopt = nl_setsbopt, \ 989 .pr_attach = nl_pru_attach, \ 990 .pr_bind = nl_pru_bind, \ 991 .pr_connect = nl_pru_connect, \ 992 .pr_disconnect = nl_pru_disconnect, \ 993 .pr_sosend = nl_sosend, \ 994 .pr_soreceive = nl_soreceive, \ 995 .pr_sockaddr = nl_sockaddr, \ 996 .pr_close = nl_close 997 998 static struct protosw netlink_raw_sw = { 999 .pr_type = SOCK_RAW, 1000 NETLINK_PROTOSW 1001 }; 1002 1003 static struct protosw netlink_dgram_sw = { 1004 .pr_type = SOCK_DGRAM, 1005 NETLINK_PROTOSW 1006 }; 1007 1008 static struct domain netlinkdomain = { 1009 .dom_family = PF_NETLINK, 1010 .dom_name = "netlink", 1011 .dom_flags = DOMF_UNLOADABLE, 1012 .dom_nprotosw = 2, 1013 .dom_protosw = { &netlink_raw_sw, &netlink_dgram_sw }, 1014 }; 1015 1016 DOMAIN_SET(netlink); 1017