xref: /freebsd/sys/netlink/netlink_domain.c (revision 1838dec31895fd4752fa8631322ab93be0705a66)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2021 Ng Peng Nam Sean
5  * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 /*
30  * This file contains socket and protocol bindings for netlink.
31  */
32 
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/malloc.h>
36 #include <sys/lock.h>
37 #include <sys/rmlock.h>
38 #include <sys/domain.h>
39 #include <sys/mbuf.h>
40 #include <sys/protosw.h>
41 #include <sys/proc.h>
42 #include <sys/ck.h>
43 #include <sys/socket.h>
44 #include <sys/socketvar.h>
45 #include <sys/sysent.h>
46 #include <sys/syslog.h>
47 #include <sys/priv.h> /* priv_check */
48 
49 #include <netlink/netlink.h>
50 #include <netlink/netlink_ctl.h>
51 #include <netlink/netlink_var.h>
52 
53 #define	DEBUG_MOD_NAME	nl_domain
54 #define	DEBUG_MAX_LEVEL	LOG_DEBUG3
55 #include <netlink/netlink_debug.h>
56 _DECLARE_DEBUG(LOG_DEBUG);
57 
58 _Static_assert((NLP_MAX_GROUPS % 64) == 0,
59     "NLP_MAX_GROUPS has to be multiple of 64");
60 _Static_assert(NLP_MAX_GROUPS >= 64,
61     "NLP_MAX_GROUPS has to be at least 64");
62 
63 #define	NLCTL_TRACKER		struct rm_priotracker nl_tracker
64 #define	NLCTL_RLOCK(_ctl)	rm_rlock(&((_ctl)->ctl_lock), &nl_tracker)
65 #define	NLCTL_RUNLOCK(_ctl)	rm_runlock(&((_ctl)->ctl_lock), &nl_tracker)
66 
67 #define	NLCTL_WLOCK(_ctl)	rm_wlock(&((_ctl)->ctl_lock))
68 #define	NLCTL_WUNLOCK(_ctl)	rm_wunlock(&((_ctl)->ctl_lock))
69 
70 static u_long nl_sendspace = NLSNDQ;
71 SYSCTL_ULONG(_net_netlink, OID_AUTO, sendspace, CTLFLAG_RW, &nl_sendspace, 0,
72     "Default netlink socket send space");
73 
74 static u_long nl_recvspace = NLSNDQ;
75 SYSCTL_ULONG(_net_netlink, OID_AUTO, recvspace, CTLFLAG_RW, &nl_recvspace, 0,
76     "Default netlink socket receive space");
77 
78 extern u_long sb_max_adj;
79 static u_long nl_maxsockbuf = 512 * 1024 * 1024; /* 512M, XXX: init based on physmem */
80 
81 uint32_t
82 nlp_get_pid(const struct nlpcb *nlp)
83 {
84 	return (nlp->nl_process_id);
85 }
86 
87 /*
88  * Looks up a nlpcb struct based on the @portid. Need to claim nlsock_mtx.
89  * Returns nlpcb pointer if present else NULL
90  */
91 static struct nlpcb *
92 nl_port_lookup(uint32_t port_id)
93 {
94 	struct nlpcb *nlp;
95 
96 	CK_LIST_FOREACH(nlp, &V_nl_ctl->ctl_port_head, nl_port_next) {
97 		if (nlp->nl_port == port_id)
98 			return (nlp);
99 	}
100 	return (NULL);
101 }
102 
103 static void
104 nl_add_group_locked(struct nlpcb *nlp, unsigned int group_id)
105 {
106 	MPASS(group_id <= NLP_MAX_GROUPS);
107 	--group_id;
108 
109 	nlp->nl_groups[group_id / 64] |= (uint64_t)1 << (group_id % 64);
110 }
111 
112 static void
113 nl_del_group_locked(struct nlpcb *nlp, unsigned int group_id)
114 {
115 	MPASS(group_id <= NLP_MAX_GROUPS);
116 	--group_id;
117 
118 	nlp->nl_groups[group_id / 64] &= ~((uint64_t)1 << (group_id % 64));
119 }
120 
121 static bool
122 nl_isset_group_locked(struct nlpcb *nlp, unsigned int group_id)
123 {
124 	MPASS(group_id <= NLP_MAX_GROUPS);
125 	--group_id;
126 
127 	return (nlp->nl_groups[group_id / 64] & ((uint64_t)1 << (group_id % 64)));
128 }
129 
130 static uint32_t
131 nl_get_groups_compat(struct nlpcb *nlp)
132 {
133 	uint32_t groups_mask = 0;
134 
135 	for (int i = 0; i < 32; i++) {
136 		if (nl_isset_group_locked(nlp, i + 1))
137 			groups_mask |= (1 << i);
138 	}
139 
140 	return (groups_mask);
141 }
142 
143 /*
144  * Broadcasts message @m to the protocol @proto group specified by @group_id
145  */
146 void
147 nl_send_group(struct mbuf *m, int num_messages, int proto, int group_id)
148 {
149 	struct nlpcb *nlp_last = NULL;
150 	struct nlpcb *nlp;
151 	NLCTL_TRACKER;
152 
153 	IF_DEBUG_LEVEL(LOG_DEBUG2) {
154 		struct nlmsghdr *hdr = mtod(m, struct nlmsghdr *);
155 		NL_LOG(LOG_DEBUG2, "MCAST mbuf len %u msg type %d len %u to group %d/%d",
156 		    m->m_len, hdr->nlmsg_type, hdr->nlmsg_len, proto, group_id);
157 	}
158 
159 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
160 	if (__predict_false(ctl == NULL)) {
161 		/*
162 		 * Can be the case when notification is sent within VNET
163 		 * which doesn't have any netlink sockets.
164 		 */
165 		m_freem(m);
166 		return;
167 	}
168 
169 	NLCTL_RLOCK(ctl);
170 
171 	int io_flags = NL_IOF_UNTRANSLATED;
172 
173 	CK_LIST_FOREACH(nlp, &ctl->ctl_pcb_head, nl_next) {
174 		if (nl_isset_group_locked(nlp, group_id) && nlp->nl_proto == proto) {
175 			if (nlp_last != NULL) {
176 				struct mbuf *m_copy;
177 				m_copy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
178 				if (m_copy != NULL)
179 					nl_send_one(m_copy, nlp_last, num_messages, io_flags);
180 				else {
181 					NLP_LOCK(nlp_last);
182 					if (nlp_last->nl_socket != NULL)
183 						sorwakeup(nlp_last->nl_socket);
184 					NLP_UNLOCK(nlp_last);
185 				}
186 			}
187 			nlp_last = nlp;
188 		}
189 	}
190 	if (nlp_last != NULL)
191 		nl_send_one(m, nlp_last, num_messages, io_flags);
192 	else
193 		m_freem(m);
194 
195 	NLCTL_RUNLOCK(ctl);
196 }
197 
198 bool
199 nl_has_listeners(int netlink_family, uint32_t groups_mask)
200 {
201 	return (V_nl_ctl != NULL);
202 }
203 
204 bool
205 nlp_has_priv(struct nlpcb *nlp, int priv)
206 {
207 	return (priv_check_cred(nlp->nl_cred, priv) == 0);
208 }
209 
210 static uint32_t
211 nl_find_port(void)
212 {
213 	/*
214 	 * app can open multiple netlink sockets.
215 	 * Start with current pid, if already taken,
216 	 * try random numbers in 65k..256k+65k space,
217 	 * avoiding clash with pids.
218 	 */
219 	if (nl_port_lookup(curproc->p_pid) == NULL)
220 		return (curproc->p_pid);
221 	for (int i = 0; i < 16; i++) {
222 		uint32_t nl_port = (arc4random() % 65536) + 65536 * 4;
223 		if (nl_port_lookup(nl_port) == 0)
224 			return (nl_port);
225 		NL_LOG(LOG_DEBUG3, "tried %u\n", nl_port);
226 	}
227 	return (curproc->p_pid);
228 }
229 
230 static int
231 nl_bind_locked(struct nlpcb *nlp, struct sockaddr_nl *snl)
232 {
233 	if (nlp->nl_bound) {
234 		if (nlp->nl_port != snl->nl_pid) {
235 			NL_LOG(LOG_DEBUG,
236 			    "bind() failed: program pid %d "
237 			    "is different from provided pid %d",
238 			    nlp->nl_port, snl->nl_pid);
239 			return (EINVAL); // XXX: better error
240 		}
241 	} else {
242 		if (snl->nl_pid == 0)
243 			snl->nl_pid = nl_find_port();
244 		if (nl_port_lookup(snl->nl_pid) != NULL)
245 			return (EADDRINUSE);
246 		nlp->nl_port = snl->nl_pid;
247 		nlp->nl_bound = true;
248 		CK_LIST_INSERT_HEAD(&V_nl_ctl->ctl_port_head, nlp, nl_port_next);
249 	}
250 	for (int i = 0; i < 32; i++) {
251 		if (snl->nl_groups & ((uint32_t)1 << i))
252 			nl_add_group_locked(nlp, i + 1);
253 		else
254 			nl_del_group_locked(nlp, i + 1);
255 	}
256 
257 	return (0);
258 }
259 
260 static int
261 nl_pru_attach(struct socket *so, int proto, struct thread *td)
262 {
263 	struct nlpcb *nlp;
264 	int error;
265 
266 	if (__predict_false(netlink_unloading != 0))
267 		return (EAFNOSUPPORT);
268 
269 	error = nl_verify_proto(proto);
270 	if (error != 0)
271 		return (error);
272 
273 	bool is_linux = SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX;
274 	NL_LOG(LOG_DEBUG2, "socket %p, %sPID %d: attaching socket to %s",
275 	    so, is_linux ? "(linux) " : "", curproc->p_pid,
276 	    nl_get_proto_name(proto));
277 
278 	/* Create per-VNET state on first socket init */
279 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
280 	if (ctl == NULL)
281 		ctl = vnet_nl_ctl_init();
282 	KASSERT(V_nl_ctl != NULL, ("nl_attach: vnet_sock_init() failed"));
283 
284 	MPASS(sotonlpcb(so) == NULL);
285 
286 	nlp = malloc(sizeof(struct nlpcb), M_PCB, M_WAITOK | M_ZERO);
287 	error = soreserve(so, nl_sendspace, nl_recvspace);
288 	if (error != 0) {
289 		free(nlp, M_PCB);
290 		return (error);
291 	}
292 	so->so_pcb = nlp;
293 	nlp->nl_socket = so;
294 	/* Copy so_cred to avoid having socket_var.h in every header */
295 	nlp->nl_cred = so->so_cred;
296 	nlp->nl_proto = proto;
297 	nlp->nl_process_id = curproc->p_pid;
298 	nlp->nl_linux = is_linux;
299 	nlp->nl_active = true;
300 	NLP_LOCK_INIT(nlp);
301 	refcount_init(&nlp->nl_refcount, 1);
302 	nl_init_io(nlp);
303 
304 	nlp->nl_taskqueue = taskqueue_create("netlink_socket", M_WAITOK,
305 	    taskqueue_thread_enqueue, &nlp->nl_taskqueue);
306 	TASK_INIT(&nlp->nl_task, 0, nl_taskqueue_handler, nlp);
307 	taskqueue_start_threads(&nlp->nl_taskqueue, 1, PWAIT,
308 	    "netlink_socket (PID %u)", nlp->nl_process_id);
309 
310 	NLCTL_WLOCK(ctl);
311 	/* XXX: check ctl is still alive */
312 	CK_LIST_INSERT_HEAD(&ctl->ctl_pcb_head, nlp, nl_next);
313 	NLCTL_WUNLOCK(ctl);
314 
315 	soisconnected(so);
316 
317 	return (0);
318 }
319 
320 static void
321 nl_pru_abort(struct socket *so)
322 {
323 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
324 	MPASS(sotonlpcb(so) != NULL);
325 	soisdisconnected(so);
326 }
327 
328 static int
329 nl_pru_bind(struct socket *so, struct sockaddr *sa, struct thread *td)
330 {
331 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
332 	struct nlpcb *nlp = sotonlpcb(so);
333 	struct sockaddr_nl *snl = (struct sockaddr_nl *)sa;
334 	int error;
335 
336 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
337 	if (snl->nl_len != sizeof(*snl)) {
338 		NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
339 		return (EINVAL);
340 	}
341 
342 
343 	NLCTL_WLOCK(ctl);
344 	NLP_LOCK(nlp);
345 	error = nl_bind_locked(nlp, snl);
346 	NLP_UNLOCK(nlp);
347 	NLCTL_WUNLOCK(ctl);
348 	NL_LOG(LOG_DEBUG2, "socket %p, bind() to %u, groups %u, error %d", so,
349 	    snl->nl_pid, snl->nl_groups, error);
350 
351 	return (error);
352 }
353 
354 
355 static int
356 nl_assign_port(struct nlpcb *nlp, uint32_t port_id)
357 {
358 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
359 	struct sockaddr_nl snl = {
360 		.nl_pid = port_id,
361 	};
362 	int error;
363 
364 	NLCTL_WLOCK(ctl);
365 	NLP_LOCK(nlp);
366 	snl.nl_groups = nl_get_groups_compat(nlp);
367 	error = nl_bind_locked(nlp, &snl);
368 	NLP_UNLOCK(nlp);
369 	NLCTL_WUNLOCK(ctl);
370 
371 	NL_LOG(LOG_DEBUG3, "socket %p, port assign: %d, error: %d", nlp->nl_socket, port_id, error);
372 	return (error);
373 }
374 
375 /*
376  * nl_autobind_port binds a unused portid to @nlp
377  * @nlp: pcb data for the netlink socket
378  * @candidate_id: first id to consider
379  */
380 static int
381 nl_autobind_port(struct nlpcb *nlp, uint32_t candidate_id)
382 {
383 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
384 	uint32_t port_id = candidate_id;
385 	NLCTL_TRACKER;
386 	bool exist;
387 	int error;
388 
389 	for (int i = 0; i < 10; i++) {
390 		NL_LOG(LOG_DEBUG3, "socket %p, trying to assign port %d", nlp->nl_socket, port_id);
391 		NLCTL_RLOCK(ctl);
392 		exist = nl_port_lookup(port_id) != 0;
393 		NLCTL_RUNLOCK(ctl);
394 		if (!exist) {
395 			error = nl_assign_port(nlp, port_id);
396 			if (error != EADDRINUSE)
397 				break;
398 		}
399 		port_id++;
400 	}
401 	NL_LOG(LOG_DEBUG3, "socket %p, autobind to %d, error: %d", nlp->nl_socket, port_id, error);
402 	return (error);
403 }
404 
405 static int
406 nl_pru_connect(struct socket *so, struct sockaddr *sa, struct thread *td)
407 {
408 	struct sockaddr_nl *snl = (struct sockaddr_nl *)sa;
409 	struct nlpcb *nlp;
410 
411 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
412 	if (snl->nl_len != sizeof(*snl)) {
413 		NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
414 		return (EINVAL);
415 	}
416 
417 	nlp = sotonlpcb(so);
418 	if (!nlp->nl_bound) {
419 		int error = nl_autobind_port(nlp, td->td_proc->p_pid);
420 		if (error != 0) {
421 			NL_LOG(LOG_DEBUG, "socket %p, nl_autobind() failed: %d", so, error);
422 			return (error);
423 		}
424 	}
425 	/* XXX: Handle socket flags & multicast */
426 	soisconnected(so);
427 
428 	NL_LOG(LOG_DEBUG2, "socket %p, connect to %u", so, snl->nl_pid);
429 
430 	return (0);
431 }
432 
433 static void
434 destroy_nlpcb(struct nlpcb *nlp)
435 {
436 	NLP_LOCK(nlp);
437 	nl_free_io(nlp);
438 	NLP_LOCK_DESTROY(nlp);
439 	free(nlp, M_PCB);
440 }
441 
442 static void
443 destroy_nlpcb_epoch(epoch_context_t ctx)
444 {
445 	struct nlpcb *nlp;
446 
447 	nlp = __containerof(ctx, struct nlpcb, nl_epoch_ctx);
448 
449 	destroy_nlpcb(nlp);
450 }
451 
452 
453 static void
454 nl_pru_detach(struct socket *so)
455 {
456 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
457 	MPASS(sotonlpcb(so) != NULL);
458 	struct nlpcb *nlp;
459 
460 	NL_LOG(LOG_DEBUG2, "detaching socket %p, PID %d", so, curproc->p_pid);
461 	nlp = sotonlpcb(so);
462 
463 	/* Mark as inactive so no new work can be enqueued */
464 	NLP_LOCK(nlp);
465 	bool was_bound = nlp->nl_bound;
466 	nlp->nl_active = false;
467 	NLP_UNLOCK(nlp);
468 
469 	/* Wait till all scheduled work has been completed  */
470 	taskqueue_drain_all(nlp->nl_taskqueue);
471 	taskqueue_free(nlp->nl_taskqueue);
472 
473 	NLCTL_WLOCK(ctl);
474 	NLP_LOCK(nlp);
475 	if (was_bound) {
476 		CK_LIST_REMOVE(nlp, nl_port_next);
477 		NL_LOG(LOG_DEBUG3, "socket %p, unlinking bound pid %u", so, nlp->nl_port);
478 	}
479 	CK_LIST_REMOVE(nlp, nl_next);
480 	nlp->nl_socket = NULL;
481 	NLP_UNLOCK(nlp);
482 	NLCTL_WUNLOCK(ctl);
483 
484 	so->so_pcb = NULL;
485 
486 	NL_LOG(LOG_DEBUG3, "socket %p, detached", so);
487 
488 	/* XXX: is delayed free needed? */
489 	NET_EPOCH_CALL(destroy_nlpcb_epoch, &nlp->nl_epoch_ctx);
490 }
491 
492 static int
493 nl_pru_disconnect(struct socket *so)
494 {
495 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
496 	MPASS(sotonlpcb(so) != NULL);
497 	return (ENOTCONN);
498 }
499 
500 static int
501 nl_pru_peeraddr(struct socket *so, struct sockaddr **sa)
502 {
503 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
504 	MPASS(sotonlpcb(so) != NULL);
505 	return (ENOTCONN);
506 }
507 
508 static int
509 nl_pru_shutdown(struct socket *so)
510 {
511 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
512 	MPASS(sotonlpcb(so) != NULL);
513 	socantsendmore(so);
514 	return (0);
515 }
516 
517 static int
518 nl_pru_sockaddr(struct socket *so, struct sockaddr **sa)
519 {
520 	struct sockaddr_nl *snl;
521 
522 	snl = malloc(sizeof(struct sockaddr_nl), M_SONAME, M_WAITOK | M_ZERO);
523 	/* TODO: set other fields */
524 	snl->nl_len = sizeof(struct sockaddr_nl);
525 	snl->nl_family = AF_NETLINK;
526 	snl->nl_pid = sotonlpcb(so)->nl_port;
527 	*sa = (struct sockaddr *)snl;
528 	return (0);
529 }
530 
531 static void
532 nl_pru_close(struct socket *so)
533 {
534 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
535 	MPASS(sotonlpcb(so) != NULL);
536 	soisdisconnected(so);
537 }
538 
539 static int
540 nl_pru_output(struct mbuf *m, struct socket *so, ...)
541 {
542 
543 	if (__predict_false(m == NULL ||
544 	    ((m->m_len < sizeof(struct nlmsghdr)) &&
545 		(m = m_pullup(m, sizeof(struct nlmsghdr))) == NULL)))
546 		return (ENOBUFS);
547 	MPASS((m->m_flags & M_PKTHDR) != 0);
548 
549 	NL_LOG(LOG_DEBUG3, "sending message to kernel async processing");
550 	nl_receive_async(m, so);
551 	return (0);
552 }
553 
554 
555 static int
556 nl_pru_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *sa,
557     struct mbuf *control, struct thread *td)
558 {
559         NL_LOG(LOG_DEBUG2, "sending message to kernel");
560 
561 	if (__predict_false(control != NULL)) {
562 		if (control->m_len) {
563 			m_freem(control);
564 			return (EINVAL);
565 		}
566 		m_freem(control);
567 	}
568 
569 	return (nl_pru_output(m, so));
570 }
571 
572 static int
573 nl_pru_rcvd(struct socket *so, int flags)
574 {
575 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
576 	MPASS(sotonlpcb(so) != NULL);
577 
578 	nl_on_transmit(sotonlpcb(so));
579 
580 	return (0);
581 }
582 
583 static int
584 nl_getoptflag(int sopt_name)
585 {
586 	switch (sopt_name) {
587 	case NETLINK_CAP_ACK:
588 		return (NLF_CAP_ACK);
589 	case NETLINK_EXT_ACK:
590 		return (NLF_EXT_ACK);
591 	case NETLINK_GET_STRICT_CHK:
592 		return (NLF_STRICT);
593 	}
594 
595 	return (0);
596 }
597 
598 static int
599 nl_ctloutput(struct socket *so, struct sockopt *sopt)
600 {
601 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
602 	struct nlpcb *nlp = sotonlpcb(so);
603 	uint32_t flag;
604 	int optval, error = 0;
605 	NLCTL_TRACKER;
606 
607 	NL_LOG(LOG_DEBUG2, "%ssockopt(%p, %d)", (sopt->sopt_dir) ? "set" : "get",
608 	    so, sopt->sopt_name);
609 
610 	switch (sopt->sopt_dir) {
611 	case SOPT_SET:
612 		switch (sopt->sopt_name) {
613 		case NETLINK_ADD_MEMBERSHIP:
614 		case NETLINK_DROP_MEMBERSHIP:
615 			sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
616 			if (optval <= 0 || optval >= NLP_MAX_GROUPS) {
617 				error = ERANGE;
618 				break;
619 			}
620 			NL_LOG(LOG_DEBUG2, "ADD/DEL group %d", (uint32_t)optval);
621 
622 			NLCTL_WLOCK(ctl);
623 			if (sopt->sopt_name == NETLINK_ADD_MEMBERSHIP)
624 				nl_add_group_locked(nlp, optval);
625 			else
626 				nl_del_group_locked(nlp, optval);
627 			NLCTL_WUNLOCK(ctl);
628 			break;
629 		case NETLINK_CAP_ACK:
630 		case NETLINK_EXT_ACK:
631 		case NETLINK_GET_STRICT_CHK:
632 			sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
633 
634 			flag = nl_getoptflag(sopt->sopt_name);
635 
636 			NLCTL_WLOCK(ctl);
637 			if (optval != 0)
638 				nlp->nl_flags |= flag;
639 			else
640 				nlp->nl_flags &= ~flag;
641 			NLCTL_WUNLOCK(ctl);
642 			break;
643 		default:
644 			error = ENOPROTOOPT;
645 		}
646 		break;
647 	case SOPT_GET:
648 		switch (sopt->sopt_name) {
649 		case NETLINK_LIST_MEMBERSHIPS:
650 			NLCTL_RLOCK(ctl);
651 			optval = nl_get_groups_compat(nlp);
652 			NLCTL_RUNLOCK(ctl);
653 			error = sooptcopyout(sopt, &optval, sizeof(optval));
654 			break;
655 		case NETLINK_CAP_ACK:
656 		case NETLINK_EXT_ACK:
657 		case NETLINK_GET_STRICT_CHK:
658 			NLCTL_RLOCK(ctl);
659 			optval = (nlp->nl_flags & nl_getoptflag(sopt->sopt_name)) != 0;
660 			NLCTL_RUNLOCK(ctl);
661 			error = sooptcopyout(sopt, &optval, sizeof(optval));
662 			break;
663 		default:
664 			error = ENOPROTOOPT;
665 		}
666 		break;
667 	default:
668 		error = ENOPROTOOPT;
669 	}
670 
671 	return (error);
672 }
673 
674 static int
675 nl_setsbopt(struct socket *so, struct sockopt *sopt)
676 {
677 	int error, optval;
678 	bool result;
679 
680 	if (sopt->sopt_name != SO_RCVBUF)
681 		return (sbsetopt(so, sopt));
682 
683 	/* Allow to override max buffer size in certain conditions */
684 
685 	error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
686 	if (error != 0)
687 		return (error);
688 	NL_LOG(LOG_DEBUG2, "socket %p, PID %d, SO_RCVBUF=%d", so, curproc->p_pid, optval);
689 	if (optval > sb_max_adj) {
690 		if (priv_check(curthread, PRIV_NET_ROUTE) != 0)
691 			return (EPERM);
692 	}
693 
694 	SOCK_RECVBUF_LOCK(so);
695 	result = sbreserve_locked_limit(so, SO_RCV, optval, nl_maxsockbuf, curthread);
696 	SOCK_RECVBUF_UNLOCK(so);
697 
698 	return (result ? 0 : ENOBUFS);
699 }
700 
701 static struct protosw netlinksw = {
702 	.pr_type = SOCK_RAW,
703 	.pr_flags = PR_ATOMIC | PR_ADDR | PR_WANTRCVD,
704 	.pr_ctloutput = nl_ctloutput,
705 	.pr_setsbopt = nl_setsbopt,
706 	.pr_abort = nl_pru_abort,
707 	.pr_attach = nl_pru_attach,
708 	.pr_bind = nl_pru_bind,
709 	.pr_connect = nl_pru_connect,
710 	.pr_detach = nl_pru_detach,
711 	.pr_disconnect = nl_pru_disconnect,
712 	.pr_peeraddr = nl_pru_peeraddr,
713 	.pr_send = nl_pru_send,
714 	.pr_rcvd = nl_pru_rcvd,
715 	.pr_shutdown = nl_pru_shutdown,
716 	.pr_sockaddr = nl_pru_sockaddr,
717 	.pr_close = nl_pru_close
718 };
719 
720 static struct domain netlinkdomain = {
721 	.dom_family = PF_NETLINK,
722 	.dom_name = "netlink",
723 	.dom_flags = DOMF_UNLOADABLE,
724 	.dom_nprotosw =		1,
725 	.dom_protosw =		{ &netlinksw },
726 };
727 
728 DOMAIN_SET(netlink);
729