xref: /freebsd/sys/netlink/netlink_domain.c (revision 7d9ef309bd09c061e9cad8ace6f7bb4c60f087e6)
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 static int sysctl_handle_nl_maxsockbuf(SYSCTL_HANDLER_ARGS);
81 SYSCTL_OID(_net_netlink, OID_AUTO, nl_maxsockbuf,
82     CTLTYPE_ULONG | CTLFLAG_RW | CTLFLAG_MPSAFE, &nl_maxsockbuf, 0,
83     sysctl_handle_nl_maxsockbuf, "LU",
84     "Maximum Netlink socket buffer size");
85 
86 uint32_t
87 nlp_get_pid(const struct nlpcb *nlp)
88 {
89 	return (nlp->nl_process_id);
90 }
91 
92 /*
93  * Looks up a nlpcb struct based on the @portid. Need to claim nlsock_mtx.
94  * Returns nlpcb pointer if present else NULL
95  */
96 static struct nlpcb *
97 nl_port_lookup(uint32_t port_id)
98 {
99 	struct nlpcb *nlp;
100 
101 	CK_LIST_FOREACH(nlp, &V_nl_ctl->ctl_port_head, nl_port_next) {
102 		if (nlp->nl_port == port_id)
103 			return (nlp);
104 	}
105 	return (NULL);
106 }
107 
108 static void
109 nl_add_group_locked(struct nlpcb *nlp, unsigned int group_id)
110 {
111 	MPASS(group_id <= NLP_MAX_GROUPS);
112 	--group_id;
113 
114 	nlp->nl_groups[group_id / 64] |= (uint64_t)1 << (group_id % 64);
115 }
116 
117 static void
118 nl_del_group_locked(struct nlpcb *nlp, unsigned int group_id)
119 {
120 	MPASS(group_id <= NLP_MAX_GROUPS);
121 	--group_id;
122 
123 	nlp->nl_groups[group_id / 64] &= ~((uint64_t)1 << (group_id % 64));
124 }
125 
126 static bool
127 nl_isset_group_locked(struct nlpcb *nlp, unsigned int group_id)
128 {
129 	MPASS(group_id <= NLP_MAX_GROUPS);
130 	--group_id;
131 
132 	return (nlp->nl_groups[group_id / 64] & ((uint64_t)1 << (group_id % 64)));
133 }
134 
135 static uint32_t
136 nl_get_groups_compat(struct nlpcb *nlp)
137 {
138 	uint32_t groups_mask = 0;
139 
140 	for (int i = 0; i < 32; i++) {
141 		if (nl_isset_group_locked(nlp, i + 1))
142 			groups_mask |= (1 << i);
143 	}
144 
145 	return (groups_mask);
146 }
147 
148 /*
149  * Broadcasts message @m to the protocol @proto group specified by @group_id
150  */
151 void
152 nl_send_group(struct mbuf *m, int num_messages, int proto, int group_id)
153 {
154 	struct nlpcb *nlp_last = NULL;
155 	struct nlpcb *nlp;
156 	NLCTL_TRACKER;
157 
158 	IF_DEBUG_LEVEL(LOG_DEBUG2) {
159 		struct nlmsghdr *hdr = mtod(m, struct nlmsghdr *);
160 		NL_LOG(LOG_DEBUG2, "MCAST mbuf len %u msg type %d len %u to group %d/%d",
161 		    m->m_len, hdr->nlmsg_type, hdr->nlmsg_len, proto, group_id);
162 	}
163 
164 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
165 	if (__predict_false(ctl == NULL)) {
166 		/*
167 		 * Can be the case when notification is sent within VNET
168 		 * which doesn't have any netlink sockets.
169 		 */
170 		m_freem(m);
171 		return;
172 	}
173 
174 	NLCTL_RLOCK(ctl);
175 
176 	int io_flags = NL_IOF_UNTRANSLATED;
177 
178 	CK_LIST_FOREACH(nlp, &ctl->ctl_pcb_head, nl_next) {
179 		if (nl_isset_group_locked(nlp, group_id) && nlp->nl_proto == proto) {
180 			if (nlp_last != NULL) {
181 				struct mbuf *m_copy;
182 				m_copy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
183 				if (m_copy != NULL)
184 					nl_send_one(m_copy, nlp_last, num_messages, io_flags);
185 				else {
186 					NLP_LOCK(nlp_last);
187 					if (nlp_last->nl_socket != NULL)
188 						sorwakeup(nlp_last->nl_socket);
189 					NLP_UNLOCK(nlp_last);
190 				}
191 			}
192 			nlp_last = nlp;
193 		}
194 	}
195 	if (nlp_last != NULL)
196 		nl_send_one(m, nlp_last, num_messages, io_flags);
197 	else
198 		m_freem(m);
199 
200 	NLCTL_RUNLOCK(ctl);
201 }
202 
203 bool
204 nl_has_listeners(int netlink_family, uint32_t groups_mask)
205 {
206 	return (V_nl_ctl != NULL);
207 }
208 
209 bool
210 nlp_has_priv(struct nlpcb *nlp, int priv)
211 {
212 	return (priv_check_cred(nlp->nl_cred, priv) == 0);
213 }
214 
215 struct ucred *
216 nlp_get_cred(struct nlpcb *nlp)
217 {
218 	return (nlp->nl_cred);
219 }
220 
221 static uint32_t
222 nl_find_port(void)
223 {
224 	/*
225 	 * app can open multiple netlink sockets.
226 	 * Start with current pid, if already taken,
227 	 * try random numbers in 65k..256k+65k space,
228 	 * avoiding clash with pids.
229 	 */
230 	if (nl_port_lookup(curproc->p_pid) == NULL)
231 		return (curproc->p_pid);
232 	for (int i = 0; i < 16; i++) {
233 		uint32_t nl_port = (arc4random() % 65536) + 65536 * 4;
234 		if (nl_port_lookup(nl_port) == 0)
235 			return (nl_port);
236 		NL_LOG(LOG_DEBUG3, "tried %u\n", nl_port);
237 	}
238 	return (curproc->p_pid);
239 }
240 
241 static int
242 nl_bind_locked(struct nlpcb *nlp, struct sockaddr_nl *snl)
243 {
244 	if (nlp->nl_bound) {
245 		if (nlp->nl_port != snl->nl_pid) {
246 			NL_LOG(LOG_DEBUG,
247 			    "bind() failed: program pid %d "
248 			    "is different from provided pid %d",
249 			    nlp->nl_port, snl->nl_pid);
250 			return (EINVAL); // XXX: better error
251 		}
252 	} else {
253 		if (snl->nl_pid == 0)
254 			snl->nl_pid = nl_find_port();
255 		if (nl_port_lookup(snl->nl_pid) != NULL)
256 			return (EADDRINUSE);
257 		nlp->nl_port = snl->nl_pid;
258 		nlp->nl_bound = true;
259 		CK_LIST_INSERT_HEAD(&V_nl_ctl->ctl_port_head, nlp, nl_port_next);
260 	}
261 	for (int i = 0; i < 32; i++) {
262 		if (snl->nl_groups & ((uint32_t)1 << i))
263 			nl_add_group_locked(nlp, i + 1);
264 		else
265 			nl_del_group_locked(nlp, i + 1);
266 	}
267 
268 	return (0);
269 }
270 
271 static int
272 nl_pru_attach(struct socket *so, int proto, struct thread *td)
273 {
274 	struct nlpcb *nlp;
275 	int error;
276 
277 	if (__predict_false(netlink_unloading != 0))
278 		return (EAFNOSUPPORT);
279 
280 	error = nl_verify_proto(proto);
281 	if (error != 0)
282 		return (error);
283 
284 	bool is_linux = SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX;
285 	NL_LOG(LOG_DEBUG2, "socket %p, %sPID %d: attaching socket to %s",
286 	    so, is_linux ? "(linux) " : "", curproc->p_pid,
287 	    nl_get_proto_name(proto));
288 
289 	/* Create per-VNET state on first socket init */
290 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
291 	if (ctl == NULL)
292 		ctl = vnet_nl_ctl_init();
293 	KASSERT(V_nl_ctl != NULL, ("nl_attach: vnet_sock_init() failed"));
294 
295 	MPASS(sotonlpcb(so) == NULL);
296 
297 	nlp = malloc(sizeof(struct nlpcb), M_PCB, M_WAITOK | M_ZERO);
298 	error = soreserve(so, nl_sendspace, nl_recvspace);
299 	if (error != 0) {
300 		free(nlp, M_PCB);
301 		return (error);
302 	}
303 	so->so_pcb = nlp;
304 	nlp->nl_socket = so;
305 	/* Copy so_cred to avoid having socket_var.h in every header */
306 	nlp->nl_cred = so->so_cred;
307 	nlp->nl_proto = proto;
308 	nlp->nl_process_id = curproc->p_pid;
309 	nlp->nl_linux = is_linux;
310 	nlp->nl_active = true;
311 	NLP_LOCK_INIT(nlp);
312 	refcount_init(&nlp->nl_refcount, 1);
313 	nl_init_io(nlp);
314 
315 	nlp->nl_taskqueue = taskqueue_create("netlink_socket", M_WAITOK,
316 	    taskqueue_thread_enqueue, &nlp->nl_taskqueue);
317 	TASK_INIT(&nlp->nl_task, 0, nl_taskqueue_handler, nlp);
318 	taskqueue_start_threads(&nlp->nl_taskqueue, 1, PWAIT,
319 	    "netlink_socket (PID %u)", nlp->nl_process_id);
320 
321 	NLCTL_WLOCK(ctl);
322 	/* XXX: check ctl is still alive */
323 	CK_LIST_INSERT_HEAD(&ctl->ctl_pcb_head, nlp, nl_next);
324 	NLCTL_WUNLOCK(ctl);
325 
326 	soisconnected(so);
327 
328 	return (0);
329 }
330 
331 static void
332 nl_pru_abort(struct socket *so)
333 {
334 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
335 	MPASS(sotonlpcb(so) != NULL);
336 	soisdisconnected(so);
337 }
338 
339 static int
340 nl_pru_bind(struct socket *so, struct sockaddr *sa, struct thread *td)
341 {
342 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
343 	struct nlpcb *nlp = sotonlpcb(so);
344 	struct sockaddr_nl *snl = (struct sockaddr_nl *)sa;
345 	int error;
346 
347 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
348 	if (snl->nl_len != sizeof(*snl)) {
349 		NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
350 		return (EINVAL);
351 	}
352 
353 
354 	NLCTL_WLOCK(ctl);
355 	NLP_LOCK(nlp);
356 	error = nl_bind_locked(nlp, snl);
357 	NLP_UNLOCK(nlp);
358 	NLCTL_WUNLOCK(ctl);
359 	NL_LOG(LOG_DEBUG2, "socket %p, bind() to %u, groups %u, error %d", so,
360 	    snl->nl_pid, snl->nl_groups, error);
361 
362 	return (error);
363 }
364 
365 
366 static int
367 nl_assign_port(struct nlpcb *nlp, uint32_t port_id)
368 {
369 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
370 	struct sockaddr_nl snl = {
371 		.nl_pid = port_id,
372 	};
373 	int error;
374 
375 	NLCTL_WLOCK(ctl);
376 	NLP_LOCK(nlp);
377 	snl.nl_groups = nl_get_groups_compat(nlp);
378 	error = nl_bind_locked(nlp, &snl);
379 	NLP_UNLOCK(nlp);
380 	NLCTL_WUNLOCK(ctl);
381 
382 	NL_LOG(LOG_DEBUG3, "socket %p, port assign: %d, error: %d", nlp->nl_socket, port_id, error);
383 	return (error);
384 }
385 
386 /*
387  * nl_autobind_port binds a unused portid to @nlp
388  * @nlp: pcb data for the netlink socket
389  * @candidate_id: first id to consider
390  */
391 static int
392 nl_autobind_port(struct nlpcb *nlp, uint32_t candidate_id)
393 {
394 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
395 	uint32_t port_id = candidate_id;
396 	NLCTL_TRACKER;
397 	bool exist;
398 	int error = EADDRINUSE;
399 
400 	for (int i = 0; i < 10; i++) {
401 		NL_LOG(LOG_DEBUG3, "socket %p, trying to assign port %d", nlp->nl_socket, port_id);
402 		NLCTL_RLOCK(ctl);
403 		exist = nl_port_lookup(port_id) != 0;
404 		NLCTL_RUNLOCK(ctl);
405 		if (!exist) {
406 			error = nl_assign_port(nlp, port_id);
407 			if (error != EADDRINUSE)
408 				break;
409 		}
410 		port_id++;
411 	}
412 	NL_LOG(LOG_DEBUG3, "socket %p, autobind to %d, error: %d", nlp->nl_socket, port_id, error);
413 	return (error);
414 }
415 
416 static int
417 nl_pru_connect(struct socket *so, struct sockaddr *sa, struct thread *td)
418 {
419 	struct sockaddr_nl *snl = (struct sockaddr_nl *)sa;
420 	struct nlpcb *nlp;
421 
422 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
423 	if (snl->nl_len != sizeof(*snl)) {
424 		NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
425 		return (EINVAL);
426 	}
427 
428 	nlp = sotonlpcb(so);
429 	if (!nlp->nl_bound) {
430 		int error = nl_autobind_port(nlp, td->td_proc->p_pid);
431 		if (error != 0) {
432 			NL_LOG(LOG_DEBUG, "socket %p, nl_autobind() failed: %d", so, error);
433 			return (error);
434 		}
435 	}
436 	/* XXX: Handle socket flags & multicast */
437 	soisconnected(so);
438 
439 	NL_LOG(LOG_DEBUG2, "socket %p, connect to %u", so, snl->nl_pid);
440 
441 	return (0);
442 }
443 
444 static void
445 destroy_nlpcb(struct nlpcb *nlp)
446 {
447 	NLP_LOCK(nlp);
448 	nl_free_io(nlp);
449 	NLP_LOCK_DESTROY(nlp);
450 	free(nlp, M_PCB);
451 }
452 
453 static void
454 destroy_nlpcb_epoch(epoch_context_t ctx)
455 {
456 	struct nlpcb *nlp;
457 
458 	nlp = __containerof(ctx, struct nlpcb, nl_epoch_ctx);
459 
460 	destroy_nlpcb(nlp);
461 }
462 
463 
464 static void
465 nl_pru_detach(struct socket *so)
466 {
467 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
468 	MPASS(sotonlpcb(so) != NULL);
469 	struct nlpcb *nlp;
470 
471 	NL_LOG(LOG_DEBUG2, "detaching socket %p, PID %d", so, curproc->p_pid);
472 	nlp = sotonlpcb(so);
473 
474 	/* Mark as inactive so no new work can be enqueued */
475 	NLP_LOCK(nlp);
476 	bool was_bound = nlp->nl_bound;
477 	nlp->nl_active = false;
478 	NLP_UNLOCK(nlp);
479 
480 	/* Wait till all scheduled work has been completed  */
481 	taskqueue_drain_all(nlp->nl_taskqueue);
482 	taskqueue_free(nlp->nl_taskqueue);
483 
484 	NLCTL_WLOCK(ctl);
485 	NLP_LOCK(nlp);
486 	if (was_bound) {
487 		CK_LIST_REMOVE(nlp, nl_port_next);
488 		NL_LOG(LOG_DEBUG3, "socket %p, unlinking bound pid %u", so, nlp->nl_port);
489 	}
490 	CK_LIST_REMOVE(nlp, nl_next);
491 	nlp->nl_socket = NULL;
492 	NLP_UNLOCK(nlp);
493 	NLCTL_WUNLOCK(ctl);
494 
495 	so->so_pcb = NULL;
496 
497 	NL_LOG(LOG_DEBUG3, "socket %p, detached", so);
498 
499 	/* XXX: is delayed free needed? */
500 	NET_EPOCH_CALL(destroy_nlpcb_epoch, &nlp->nl_epoch_ctx);
501 }
502 
503 static int
504 nl_pru_disconnect(struct socket *so)
505 {
506 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
507 	MPASS(sotonlpcb(so) != NULL);
508 	return (ENOTCONN);
509 }
510 
511 static int
512 nl_pru_peeraddr(struct socket *so, struct sockaddr **sa)
513 {
514 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
515 	MPASS(sotonlpcb(so) != NULL);
516 	return (ENOTCONN);
517 }
518 
519 static int
520 nl_pru_shutdown(struct socket *so)
521 {
522 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
523 	MPASS(sotonlpcb(so) != NULL);
524 	socantsendmore(so);
525 	return (0);
526 }
527 
528 static int
529 nl_pru_sockaddr(struct socket *so, struct sockaddr **sa)
530 {
531 	struct sockaddr_nl *snl;
532 
533 	snl = malloc(sizeof(struct sockaddr_nl), M_SONAME, M_WAITOK | M_ZERO);
534 	/* TODO: set other fields */
535 	snl->nl_len = sizeof(struct sockaddr_nl);
536 	snl->nl_family = AF_NETLINK;
537 	snl->nl_pid = sotonlpcb(so)->nl_port;
538 	*sa = (struct sockaddr *)snl;
539 	return (0);
540 }
541 
542 static void
543 nl_pru_close(struct socket *so)
544 {
545 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
546 	MPASS(sotonlpcb(so) != NULL);
547 	soisdisconnected(so);
548 }
549 
550 static int
551 nl_pru_output(struct mbuf *m, struct socket *so, ...)
552 {
553 
554 	if (__predict_false(m == NULL ||
555 	    ((m->m_len < sizeof(struct nlmsghdr)) &&
556 		(m = m_pullup(m, sizeof(struct nlmsghdr))) == NULL)))
557 		return (ENOBUFS);
558 	MPASS((m->m_flags & M_PKTHDR) != 0);
559 
560 	NL_LOG(LOG_DEBUG3, "sending message to kernel async processing");
561 	nl_receive_async(m, so);
562 	return (0);
563 }
564 
565 
566 static int
567 nl_pru_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *sa,
568     struct mbuf *control, struct thread *td)
569 {
570         NL_LOG(LOG_DEBUG2, "sending message to kernel");
571 
572 	if (__predict_false(control != NULL)) {
573 		if (control->m_len) {
574 			m_freem(control);
575 			return (EINVAL);
576 		}
577 		m_freem(control);
578 	}
579 
580 	return (nl_pru_output(m, so));
581 }
582 
583 static int
584 nl_pru_rcvd(struct socket *so, int flags)
585 {
586 	NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
587 	MPASS(sotonlpcb(so) != NULL);
588 
589 	nl_on_transmit(sotonlpcb(so));
590 
591 	return (0);
592 }
593 
594 static int
595 nl_getoptflag(int sopt_name)
596 {
597 	switch (sopt_name) {
598 	case NETLINK_CAP_ACK:
599 		return (NLF_CAP_ACK);
600 	case NETLINK_EXT_ACK:
601 		return (NLF_EXT_ACK);
602 	case NETLINK_GET_STRICT_CHK:
603 		return (NLF_STRICT);
604 	}
605 
606 	return (0);
607 }
608 
609 static int
610 nl_ctloutput(struct socket *so, struct sockopt *sopt)
611 {
612 	struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
613 	struct nlpcb *nlp = sotonlpcb(so);
614 	uint32_t flag;
615 	int optval, error = 0;
616 	NLCTL_TRACKER;
617 
618 	NL_LOG(LOG_DEBUG2, "%ssockopt(%p, %d)", (sopt->sopt_dir) ? "set" : "get",
619 	    so, sopt->sopt_name);
620 
621 	switch (sopt->sopt_dir) {
622 	case SOPT_SET:
623 		switch (sopt->sopt_name) {
624 		case NETLINK_ADD_MEMBERSHIP:
625 		case NETLINK_DROP_MEMBERSHIP:
626 			error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
627 			if (error != 0)
628 				break;
629 			if (optval <= 0 || optval >= NLP_MAX_GROUPS) {
630 				error = ERANGE;
631 				break;
632 			}
633 			NL_LOG(LOG_DEBUG2, "ADD/DEL group %d", (uint32_t)optval);
634 
635 			NLCTL_WLOCK(ctl);
636 			if (sopt->sopt_name == NETLINK_ADD_MEMBERSHIP)
637 				nl_add_group_locked(nlp, optval);
638 			else
639 				nl_del_group_locked(nlp, optval);
640 			NLCTL_WUNLOCK(ctl);
641 			break;
642 		case NETLINK_CAP_ACK:
643 		case NETLINK_EXT_ACK:
644 		case NETLINK_GET_STRICT_CHK:
645 			error = sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
646 			if (error != 0)
647 				break;
648 
649 			flag = nl_getoptflag(sopt->sopt_name);
650 
651 			NLCTL_WLOCK(ctl);
652 			if (optval != 0)
653 				nlp->nl_flags |= flag;
654 			else
655 				nlp->nl_flags &= ~flag;
656 			NLCTL_WUNLOCK(ctl);
657 			break;
658 		default:
659 			error = ENOPROTOOPT;
660 		}
661 		break;
662 	case SOPT_GET:
663 		switch (sopt->sopt_name) {
664 		case NETLINK_LIST_MEMBERSHIPS:
665 			NLCTL_RLOCK(ctl);
666 			optval = nl_get_groups_compat(nlp);
667 			NLCTL_RUNLOCK(ctl);
668 			error = sooptcopyout(sopt, &optval, sizeof(optval));
669 			break;
670 		case NETLINK_CAP_ACK:
671 		case NETLINK_EXT_ACK:
672 		case NETLINK_GET_STRICT_CHK:
673 			NLCTL_RLOCK(ctl);
674 			optval = (nlp->nl_flags & nl_getoptflag(sopt->sopt_name)) != 0;
675 			NLCTL_RUNLOCK(ctl);
676 			error = sooptcopyout(sopt, &optval, sizeof(optval));
677 			break;
678 		default:
679 			error = ENOPROTOOPT;
680 		}
681 		break;
682 	default:
683 		error = ENOPROTOOPT;
684 	}
685 
686 	return (error);
687 }
688 
689 static int
690 sysctl_handle_nl_maxsockbuf(SYSCTL_HANDLER_ARGS)
691 {
692 	int error = 0;
693 	u_long tmp_maxsockbuf = nl_maxsockbuf;
694 
695 	error = sysctl_handle_long(oidp, &tmp_maxsockbuf, arg2, req);
696 	if (error || !req->newptr)
697 		return (error);
698 	if (tmp_maxsockbuf < MSIZE + MCLBYTES)
699 		return (EINVAL);
700 	nl_maxsockbuf = tmp_maxsockbuf;
701 
702 	return (0);
703 }
704 
705 static int
706 nl_setsbopt(struct socket *so, struct sockopt *sopt)
707 {
708 	int error, optval;
709 	bool result;
710 
711 	if (sopt->sopt_name != SO_RCVBUF)
712 		return (sbsetopt(so, sopt));
713 
714 	/* Allow to override max buffer size in certain conditions */
715 
716 	error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
717 	if (error != 0)
718 		return (error);
719 	NL_LOG(LOG_DEBUG2, "socket %p, PID %d, SO_RCVBUF=%d", so, curproc->p_pid, optval);
720 	if (optval > sb_max_adj) {
721 		if (priv_check(curthread, PRIV_NET_ROUTE) != 0)
722 			return (EPERM);
723 	}
724 
725 	SOCK_RECVBUF_LOCK(so);
726 	result = sbreserve_locked_limit(so, SO_RCV, optval, nl_maxsockbuf, curthread);
727 	SOCK_RECVBUF_UNLOCK(so);
728 
729 	return (result ? 0 : ENOBUFS);
730 }
731 
732 #define	NETLINK_PROTOSW						\
733 	.pr_flags = PR_ATOMIC | PR_ADDR | PR_WANTRCVD,		\
734 	.pr_ctloutput = nl_ctloutput,				\
735 	.pr_setsbopt = nl_setsbopt,				\
736 	.pr_abort = nl_pru_abort,				\
737 	.pr_attach = nl_pru_attach,				\
738 	.pr_bind = nl_pru_bind,					\
739 	.pr_connect = nl_pru_connect,				\
740 	.pr_detach = nl_pru_detach,				\
741 	.pr_disconnect = nl_pru_disconnect,			\
742 	.pr_peeraddr = nl_pru_peeraddr,				\
743 	.pr_send = nl_pru_send,					\
744 	.pr_rcvd = nl_pru_rcvd,					\
745 	.pr_shutdown = nl_pru_shutdown,				\
746 	.pr_sockaddr = nl_pru_sockaddr,				\
747 	.pr_close = nl_pru_close
748 
749 static struct protosw netlink_raw_sw = {
750 	.pr_type = SOCK_RAW,
751 	NETLINK_PROTOSW
752 };
753 
754 static struct protosw netlink_dgram_sw = {
755 	.pr_type = SOCK_DGRAM,
756 	NETLINK_PROTOSW
757 };
758 
759 static struct domain netlinkdomain = {
760 	.dom_family = PF_NETLINK,
761 	.dom_name = "netlink",
762 	.dom_flags = DOMF_UNLOADABLE,
763 	.dom_nprotosw =		2,
764 	.dom_protosw =		{ &netlink_raw_sw, &netlink_dgram_sw },
765 };
766 
767 DOMAIN_SET(netlink);
768