xref: /freebsd/sys/kern/uipc_usrreq.c (revision eaa797943eeac5614edfdc8f6309f332343c3dd2)
1 /*-
2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
3  *	The Regents of the University of California.
4  * Copyright (c) 2004-2009 Robert N. M. Watson
5  * All rights reserved.
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  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	From: @(#)uipc_usrreq.c	8.3 (Berkeley) 1/4/94
32  */
33 
34 /*
35  * UNIX Domain (Local) Sockets
36  *
37  * This is an implementation of UNIX (local) domain sockets.  Each socket has
38  * an associated struct unpcb (UNIX protocol control block).  Stream sockets
39  * may be connected to 0 or 1 other socket.  Datagram sockets may be
40  * connected to 0, 1, or many other sockets.  Sockets may be created and
41  * connected in pairs (socketpair(2)), or bound/connected to using the file
42  * system name space.  For most purposes, only the receive socket buffer is
43  * used, as sending on one socket delivers directly to the receive socket
44  * buffer of a second socket.
45  *
46  * The implementation is substantially complicated by the fact that
47  * "ancillary data", such as file descriptors or credentials, may be passed
48  * across UNIX domain sockets.  The potential for passing UNIX domain sockets
49  * over other UNIX domain sockets requires the implementation of a simple
50  * garbage collector to find and tear down cycles of disconnected sockets.
51  *
52  * TODO:
53  *	RDM
54  *	rethink name space problems
55  *	need a proper out-of-band
56  */
57 
58 #include <sys/cdefs.h>
59 __FBSDID("$FreeBSD$");
60 
61 #include "opt_ddb.h"
62 
63 #include <sys/param.h>
64 #include <sys/capsicum.h>
65 #include <sys/domain.h>
66 #include <sys/fcntl.h>
67 #include <sys/malloc.h>		/* XXX must be before <sys/file.h> */
68 #include <sys/eventhandler.h>
69 #include <sys/file.h>
70 #include <sys/filedesc.h>
71 #include <sys/kernel.h>
72 #include <sys/lock.h>
73 #include <sys/mbuf.h>
74 #include <sys/mount.h>
75 #include <sys/mutex.h>
76 #include <sys/namei.h>
77 #include <sys/proc.h>
78 #include <sys/protosw.h>
79 #include <sys/queue.h>
80 #include <sys/resourcevar.h>
81 #include <sys/rwlock.h>
82 #include <sys/socket.h>
83 #include <sys/socketvar.h>
84 #include <sys/signalvar.h>
85 #include <sys/stat.h>
86 #include <sys/sx.h>
87 #include <sys/sysctl.h>
88 #include <sys/systm.h>
89 #include <sys/taskqueue.h>
90 #include <sys/un.h>
91 #include <sys/unpcb.h>
92 #include <sys/vnode.h>
93 
94 #include <net/vnet.h>
95 
96 #ifdef DDB
97 #include <ddb/ddb.h>
98 #endif
99 
100 #include <security/mac/mac_framework.h>
101 
102 #include <vm/uma.h>
103 
104 MALLOC_DECLARE(M_FILECAPS);
105 
106 /*
107  * Locking key:
108  * (l)	Locked using list lock
109  * (g)	Locked using linkage lock
110  */
111 
112 static uma_zone_t	unp_zone;
113 static unp_gen_t	unp_gencnt;	/* (l) */
114 static u_int		unp_count;	/* (l) Count of local sockets. */
115 static ino_t		unp_ino;	/* Prototype for fake inode numbers. */
116 static int		unp_rights;	/* (g) File descriptors in flight. */
117 static struct unp_head	unp_shead;	/* (l) List of stream sockets. */
118 static struct unp_head	unp_dhead;	/* (l) List of datagram sockets. */
119 static struct unp_head	unp_sphead;	/* (l) List of seqpacket sockets. */
120 
121 struct unp_defer {
122 	SLIST_ENTRY(unp_defer) ud_link;
123 	struct file *ud_fp;
124 };
125 static SLIST_HEAD(, unp_defer) unp_defers;
126 static int unp_defers_count;
127 
128 static const struct sockaddr	sun_noname = { sizeof(sun_noname), AF_LOCAL };
129 
130 /*
131  * Garbage collection of cyclic file descriptor/socket references occurs
132  * asynchronously in a taskqueue context in order to avoid recursion and
133  * reentrance in the UNIX domain socket, file descriptor, and socket layer
134  * code.  See unp_gc() for a full description.
135  */
136 static struct timeout_task unp_gc_task;
137 
138 /*
139  * The close of unix domain sockets attached as SCM_RIGHTS is
140  * postponed to the taskqueue, to avoid arbitrary recursion depth.
141  * The attached sockets might have another sockets attached.
142  */
143 static struct task	unp_defer_task;
144 
145 /*
146  * Both send and receive buffers are allocated PIPSIZ bytes of buffering for
147  * stream sockets, although the total for sender and receiver is actually
148  * only PIPSIZ.
149  *
150  * Datagram sockets really use the sendspace as the maximum datagram size,
151  * and don't really want to reserve the sendspace.  Their recvspace should be
152  * large enough for at least one max-size datagram plus address.
153  */
154 #ifndef PIPSIZ
155 #define	PIPSIZ	8192
156 #endif
157 static u_long	unpst_sendspace = PIPSIZ;
158 static u_long	unpst_recvspace = PIPSIZ;
159 static u_long	unpdg_sendspace = 2*1024;	/* really max datagram size */
160 static u_long	unpdg_recvspace = 4*1024;
161 static u_long	unpsp_sendspace = PIPSIZ;	/* really max datagram size */
162 static u_long	unpsp_recvspace = PIPSIZ;
163 
164 static SYSCTL_NODE(_net, PF_LOCAL, local, CTLFLAG_RW, 0, "Local domain");
165 static SYSCTL_NODE(_net_local, SOCK_STREAM, stream, CTLFLAG_RW, 0,
166     "SOCK_STREAM");
167 static SYSCTL_NODE(_net_local, SOCK_DGRAM, dgram, CTLFLAG_RW, 0, "SOCK_DGRAM");
168 static SYSCTL_NODE(_net_local, SOCK_SEQPACKET, seqpacket, CTLFLAG_RW, 0,
169     "SOCK_SEQPACKET");
170 
171 SYSCTL_ULONG(_net_local_stream, OID_AUTO, sendspace, CTLFLAG_RW,
172 	   &unpst_sendspace, 0, "Default stream send space.");
173 SYSCTL_ULONG(_net_local_stream, OID_AUTO, recvspace, CTLFLAG_RW,
174 	   &unpst_recvspace, 0, "Default stream receive space.");
175 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, maxdgram, CTLFLAG_RW,
176 	   &unpdg_sendspace, 0, "Default datagram send space.");
177 SYSCTL_ULONG(_net_local_dgram, OID_AUTO, recvspace, CTLFLAG_RW,
178 	   &unpdg_recvspace, 0, "Default datagram receive space.");
179 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, maxseqpacket, CTLFLAG_RW,
180 	   &unpsp_sendspace, 0, "Default seqpacket send space.");
181 SYSCTL_ULONG(_net_local_seqpacket, OID_AUTO, recvspace, CTLFLAG_RW,
182 	   &unpsp_recvspace, 0, "Default seqpacket receive space.");
183 SYSCTL_INT(_net_local, OID_AUTO, inflight, CTLFLAG_RD, &unp_rights, 0,
184     "File descriptors in flight.");
185 SYSCTL_INT(_net_local, OID_AUTO, deferred, CTLFLAG_RD,
186     &unp_defers_count, 0,
187     "File descriptors deferred to taskqueue for close.");
188 
189 /*
190  * Locking and synchronization:
191  *
192  * Three types of locks exit in the local domain socket implementation: a
193  * global list mutex, a global linkage rwlock, and per-unpcb mutexes.  Of the
194  * global locks, the list lock protects the socket count, global generation
195  * number, and stream/datagram global lists.  The linkage lock protects the
196  * interconnection of unpcbs, the v_socket and unp_vnode pointers, and can be
197  * held exclusively over the acquisition of multiple unpcb locks to prevent
198  * deadlock.
199  *
200  * UNIX domain sockets each have an unpcb hung off of their so_pcb pointer,
201  * allocated in pru_attach() and freed in pru_detach().  The validity of that
202  * pointer is an invariant, so no lock is required to dereference the so_pcb
203  * pointer if a valid socket reference is held by the caller.  In practice,
204  * this is always true during operations performed on a socket.  Each unpcb
205  * has a back-pointer to its socket, unp_socket, which will be stable under
206  * the same circumstances.
207  *
208  * This pointer may only be safely dereferenced as long as a valid reference
209  * to the unpcb is held.  Typically, this reference will be from the socket,
210  * or from another unpcb when the referring unpcb's lock is held (in order
211  * that the reference not be invalidated during use).  For example, to follow
212  * unp->unp_conn->unp_socket, you need unlock the lock on unp, not unp_conn,
213  * as unp_socket remains valid as long as the reference to unp_conn is valid.
214  *
215  * Fields of unpcbss are locked using a per-unpcb lock, unp_mtx.  Individual
216  * atomic reads without the lock may be performed "lockless", but more
217  * complex reads and read-modify-writes require the mutex to be held.  No
218  * lock order is defined between unpcb locks -- multiple unpcb locks may be
219  * acquired at the same time only when holding the linkage rwlock
220  * exclusively, which prevents deadlocks.
221  *
222  * Blocking with UNIX domain sockets is a tricky issue: unlike most network
223  * protocols, bind() is a non-atomic operation, and connect() requires
224  * potential sleeping in the protocol, due to potentially waiting on local or
225  * distributed file systems.  We try to separate "lookup" operations, which
226  * may sleep, and the IPC operations themselves, which typically can occur
227  * with relative atomicity as locks can be held over the entire operation.
228  *
229  * Another tricky issue is simultaneous multi-threaded or multi-process
230  * access to a single UNIX domain socket.  These are handled by the flags
231  * UNP_CONNECTING and UNP_BINDING, which prevent concurrent connecting or
232  * binding, both of which involve dropping UNIX domain socket locks in order
233  * to perform namei() and other file system operations.
234  */
235 static struct rwlock	unp_link_rwlock;
236 static struct mtx	unp_list_lock;
237 static struct mtx	unp_defers_lock;
238 
239 #define	UNP_LINK_LOCK_INIT()		rw_init(&unp_link_rwlock,	\
240 					    "unp_link_rwlock")
241 
242 #define	UNP_LINK_LOCK_ASSERT()	rw_assert(&unp_link_rwlock,	\
243 					    RA_LOCKED)
244 #define	UNP_LINK_UNLOCK_ASSERT()	rw_assert(&unp_link_rwlock,	\
245 					    RA_UNLOCKED)
246 
247 #define	UNP_LINK_RLOCK()		rw_rlock(&unp_link_rwlock)
248 #define	UNP_LINK_RUNLOCK()		rw_runlock(&unp_link_rwlock)
249 #define	UNP_LINK_WLOCK()		rw_wlock(&unp_link_rwlock)
250 #define	UNP_LINK_WUNLOCK()		rw_wunlock(&unp_link_rwlock)
251 #define	UNP_LINK_WLOCK_ASSERT()		rw_assert(&unp_link_rwlock,	\
252 					    RA_WLOCKED)
253 
254 #define	UNP_LIST_LOCK_INIT()		mtx_init(&unp_list_lock,	\
255 					    "unp_list_lock", NULL, MTX_DEF)
256 #define	UNP_LIST_LOCK()			mtx_lock(&unp_list_lock)
257 #define	UNP_LIST_UNLOCK()		mtx_unlock(&unp_list_lock)
258 
259 #define	UNP_DEFERRED_LOCK_INIT()	mtx_init(&unp_defers_lock, \
260 					    "unp_defer", NULL, MTX_DEF)
261 #define	UNP_DEFERRED_LOCK()		mtx_lock(&unp_defers_lock)
262 #define	UNP_DEFERRED_UNLOCK()		mtx_unlock(&unp_defers_lock)
263 
264 #define UNP_PCB_LOCK_INIT(unp)		mtx_init(&(unp)->unp_mtx,	\
265 					    "unp_mtx", "unp_mtx",	\
266 					    MTX_DUPOK|MTX_DEF|MTX_RECURSE)
267 #define	UNP_PCB_LOCK_DESTROY(unp)	mtx_destroy(&(unp)->unp_mtx)
268 #define	UNP_PCB_LOCK(unp)		mtx_lock(&(unp)->unp_mtx)
269 #define	UNP_PCB_UNLOCK(unp)		mtx_unlock(&(unp)->unp_mtx)
270 #define	UNP_PCB_LOCK_ASSERT(unp)	mtx_assert(&(unp)->unp_mtx, MA_OWNED)
271 
272 static int	uipc_connect2(struct socket *, struct socket *);
273 static int	uipc_ctloutput(struct socket *, struct sockopt *);
274 static int	unp_connect(struct socket *, struct sockaddr *,
275 		    struct thread *);
276 static int	unp_connectat(int, struct socket *, struct sockaddr *,
277 		    struct thread *);
278 static int	unp_connect2(struct socket *so, struct socket *so2, int);
279 static void	unp_disconnect(struct unpcb *unp, struct unpcb *unp2);
280 static void	unp_dispose(struct socket *so);
281 static void	unp_dispose_mbuf(struct mbuf *);
282 static void	unp_shutdown(struct unpcb *);
283 static void	unp_drop(struct unpcb *);
284 static void	unp_gc(__unused void *, int);
285 static void	unp_scan(struct mbuf *, void (*)(struct filedescent **, int));
286 static void	unp_discard(struct file *);
287 static void	unp_freerights(struct filedescent **, int);
288 static void	unp_init(void);
289 static int	unp_internalize(struct mbuf **, struct thread *);
290 static void	unp_internalize_fp(struct file *);
291 static int	unp_externalize(struct mbuf *, struct mbuf **, int);
292 static int	unp_externalize_fp(struct file *);
293 static struct mbuf	*unp_addsockcred(struct thread *, struct mbuf *);
294 static void	unp_process_defers(void * __unused, int);
295 
296 /*
297  * Definitions of protocols supported in the LOCAL domain.
298  */
299 static struct domain localdomain;
300 static struct pr_usrreqs uipc_usrreqs_dgram, uipc_usrreqs_stream;
301 static struct pr_usrreqs uipc_usrreqs_seqpacket;
302 static struct protosw localsw[] = {
303 {
304 	.pr_type =		SOCK_STREAM,
305 	.pr_domain =		&localdomain,
306 	.pr_flags =		PR_CONNREQUIRED|PR_WANTRCVD|PR_RIGHTS,
307 	.pr_ctloutput =		&uipc_ctloutput,
308 	.pr_usrreqs =		&uipc_usrreqs_stream
309 },
310 {
311 	.pr_type =		SOCK_DGRAM,
312 	.pr_domain =		&localdomain,
313 	.pr_flags =		PR_ATOMIC|PR_ADDR|PR_RIGHTS,
314 	.pr_ctloutput =		&uipc_ctloutput,
315 	.pr_usrreqs =		&uipc_usrreqs_dgram
316 },
317 {
318 	.pr_type =		SOCK_SEQPACKET,
319 	.pr_domain =		&localdomain,
320 
321 	/*
322 	 * XXXRW: For now, PR_ADDR because soreceive will bump into them
323 	 * due to our use of sbappendaddr.  A new sbappend variants is needed
324 	 * that supports both atomic record writes and control data.
325 	 */
326 	.pr_flags =		PR_ADDR|PR_ATOMIC|PR_CONNREQUIRED|PR_WANTRCVD|
327 				    PR_RIGHTS,
328 	.pr_ctloutput =		&uipc_ctloutput,
329 	.pr_usrreqs =		&uipc_usrreqs_seqpacket,
330 },
331 };
332 
333 static struct domain localdomain = {
334 	.dom_family =		AF_LOCAL,
335 	.dom_name =		"local",
336 	.dom_init =		unp_init,
337 	.dom_externalize =	unp_externalize,
338 	.dom_dispose =		unp_dispose,
339 	.dom_protosw =		localsw,
340 	.dom_protoswNPROTOSW =	&localsw[nitems(localsw)]
341 };
342 DOMAIN_SET(local);
343 
344 static void
345 uipc_abort(struct socket *so)
346 {
347 	struct unpcb *unp, *unp2;
348 
349 	unp = sotounpcb(so);
350 	KASSERT(unp != NULL, ("uipc_abort: unp == NULL"));
351 
352 	UNP_LINK_WLOCK();
353 	UNP_PCB_LOCK(unp);
354 	unp2 = unp->unp_conn;
355 	if (unp2 != NULL) {
356 		UNP_PCB_LOCK(unp2);
357 		unp_drop(unp2);
358 		UNP_PCB_UNLOCK(unp2);
359 	}
360 	UNP_PCB_UNLOCK(unp);
361 	UNP_LINK_WUNLOCK();
362 }
363 
364 static int
365 uipc_accept(struct socket *so, struct sockaddr **nam)
366 {
367 	struct unpcb *unp, *unp2;
368 	const struct sockaddr *sa;
369 
370 	/*
371 	 * Pass back name of connected socket, if it was bound and we are
372 	 * still connected (our peer may have closed already!).
373 	 */
374 	unp = sotounpcb(so);
375 	KASSERT(unp != NULL, ("uipc_accept: unp == NULL"));
376 
377 	*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
378 	UNP_LINK_RLOCK();
379 	unp2 = unp->unp_conn;
380 	if (unp2 != NULL && unp2->unp_addr != NULL) {
381 		UNP_PCB_LOCK(unp2);
382 		sa = (struct sockaddr *) unp2->unp_addr;
383 		bcopy(sa, *nam, sa->sa_len);
384 		UNP_PCB_UNLOCK(unp2);
385 	} else {
386 		sa = &sun_noname;
387 		bcopy(sa, *nam, sa->sa_len);
388 	}
389 	UNP_LINK_RUNLOCK();
390 	return (0);
391 }
392 
393 static int
394 uipc_attach(struct socket *so, int proto, struct thread *td)
395 {
396 	u_long sendspace, recvspace;
397 	struct unpcb *unp;
398 	int error;
399 
400 	KASSERT(so->so_pcb == NULL, ("uipc_attach: so_pcb != NULL"));
401 	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
402 		switch (so->so_type) {
403 		case SOCK_STREAM:
404 			sendspace = unpst_sendspace;
405 			recvspace = unpst_recvspace;
406 			break;
407 
408 		case SOCK_DGRAM:
409 			sendspace = unpdg_sendspace;
410 			recvspace = unpdg_recvspace;
411 			break;
412 
413 		case SOCK_SEQPACKET:
414 			sendspace = unpsp_sendspace;
415 			recvspace = unpsp_recvspace;
416 			break;
417 
418 		default:
419 			panic("uipc_attach");
420 		}
421 		error = soreserve(so, sendspace, recvspace);
422 		if (error)
423 			return (error);
424 	}
425 	unp = uma_zalloc(unp_zone, M_NOWAIT | M_ZERO);
426 	if (unp == NULL)
427 		return (ENOBUFS);
428 	LIST_INIT(&unp->unp_refs);
429 	UNP_PCB_LOCK_INIT(unp);
430 	unp->unp_socket = so;
431 	so->so_pcb = unp;
432 	unp->unp_refcount = 1;
433 	if (so->so_head != NULL)
434 		unp->unp_flags |= UNP_NASCENT;
435 
436 	UNP_LIST_LOCK();
437 	unp->unp_gencnt = ++unp_gencnt;
438 	unp_count++;
439 	switch (so->so_type) {
440 	case SOCK_STREAM:
441 		LIST_INSERT_HEAD(&unp_shead, unp, unp_link);
442 		break;
443 
444 	case SOCK_DGRAM:
445 		LIST_INSERT_HEAD(&unp_dhead, unp, unp_link);
446 		break;
447 
448 	case SOCK_SEQPACKET:
449 		LIST_INSERT_HEAD(&unp_sphead, unp, unp_link);
450 		break;
451 
452 	default:
453 		panic("uipc_attach");
454 	}
455 	UNP_LIST_UNLOCK();
456 
457 	return (0);
458 }
459 
460 static int
461 uipc_bindat(int fd, struct socket *so, struct sockaddr *nam, struct thread *td)
462 {
463 	struct sockaddr_un *soun = (struct sockaddr_un *)nam;
464 	struct vattr vattr;
465 	int error, namelen;
466 	struct nameidata nd;
467 	struct unpcb *unp;
468 	struct vnode *vp;
469 	struct mount *mp;
470 	cap_rights_t rights;
471 	char *buf;
472 
473 	if (nam->sa_family != AF_UNIX)
474 		return (EAFNOSUPPORT);
475 
476 	unp = sotounpcb(so);
477 	KASSERT(unp != NULL, ("uipc_bind: unp == NULL"));
478 
479 	if (soun->sun_len > sizeof(struct sockaddr_un))
480 		return (EINVAL);
481 	namelen = soun->sun_len - offsetof(struct sockaddr_un, sun_path);
482 	if (namelen <= 0)
483 		return (EINVAL);
484 
485 	/*
486 	 * We don't allow simultaneous bind() calls on a single UNIX domain
487 	 * socket, so flag in-progress operations, and return an error if an
488 	 * operation is already in progress.
489 	 *
490 	 * Historically, we have not allowed a socket to be rebound, so this
491 	 * also returns an error.  Not allowing re-binding simplifies the
492 	 * implementation and avoids a great many possible failure modes.
493 	 */
494 	UNP_PCB_LOCK(unp);
495 	if (unp->unp_vnode != NULL) {
496 		UNP_PCB_UNLOCK(unp);
497 		return (EINVAL);
498 	}
499 	if (unp->unp_flags & UNP_BINDING) {
500 		UNP_PCB_UNLOCK(unp);
501 		return (EALREADY);
502 	}
503 	unp->unp_flags |= UNP_BINDING;
504 	UNP_PCB_UNLOCK(unp);
505 
506 	buf = malloc(namelen + 1, M_TEMP, M_WAITOK);
507 	bcopy(soun->sun_path, buf, namelen);
508 	buf[namelen] = 0;
509 
510 restart:
511 	NDINIT_ATRIGHTS(&nd, CREATE, NOFOLLOW | LOCKPARENT | SAVENAME | NOCACHE,
512 	    UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_BINDAT), td);
513 /* SHOULD BE ABLE TO ADOPT EXISTING AND wakeup() ALA FIFO's */
514 	error = namei(&nd);
515 	if (error)
516 		goto error;
517 	vp = nd.ni_vp;
518 	if (vp != NULL || vn_start_write(nd.ni_dvp, &mp, V_NOWAIT) != 0) {
519 		NDFREE(&nd, NDF_ONLY_PNBUF);
520 		if (nd.ni_dvp == vp)
521 			vrele(nd.ni_dvp);
522 		else
523 			vput(nd.ni_dvp);
524 		if (vp != NULL) {
525 			vrele(vp);
526 			error = EADDRINUSE;
527 			goto error;
528 		}
529 		error = vn_start_write(NULL, &mp, V_XSLEEP | PCATCH);
530 		if (error)
531 			goto error;
532 		goto restart;
533 	}
534 	VATTR_NULL(&vattr);
535 	vattr.va_type = VSOCK;
536 	vattr.va_mode = (ACCESSPERMS & ~td->td_proc->p_fd->fd_cmask);
537 #ifdef MAC
538 	error = mac_vnode_check_create(td->td_ucred, nd.ni_dvp, &nd.ni_cnd,
539 	    &vattr);
540 #endif
541 	if (error == 0)
542 		error = VOP_CREATE(nd.ni_dvp, &nd.ni_vp, &nd.ni_cnd, &vattr);
543 	NDFREE(&nd, NDF_ONLY_PNBUF);
544 	vput(nd.ni_dvp);
545 	if (error) {
546 		vn_finished_write(mp);
547 		goto error;
548 	}
549 	vp = nd.ni_vp;
550 	ASSERT_VOP_ELOCKED(vp, "uipc_bind");
551 	soun = (struct sockaddr_un *)sodupsockaddr(nam, M_WAITOK);
552 
553 	UNP_LINK_WLOCK();
554 	UNP_PCB_LOCK(unp);
555 	VOP_UNP_BIND(vp, unp->unp_socket);
556 	unp->unp_vnode = vp;
557 	unp->unp_addr = soun;
558 	unp->unp_flags &= ~UNP_BINDING;
559 	UNP_PCB_UNLOCK(unp);
560 	UNP_LINK_WUNLOCK();
561 	VOP_UNLOCK(vp, 0);
562 	vn_finished_write(mp);
563 	free(buf, M_TEMP);
564 	return (0);
565 
566 error:
567 	UNP_PCB_LOCK(unp);
568 	unp->unp_flags &= ~UNP_BINDING;
569 	UNP_PCB_UNLOCK(unp);
570 	free(buf, M_TEMP);
571 	return (error);
572 }
573 
574 static int
575 uipc_bind(struct socket *so, struct sockaddr *nam, struct thread *td)
576 {
577 
578 	return (uipc_bindat(AT_FDCWD, so, nam, td));
579 }
580 
581 static int
582 uipc_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
583 {
584 	int error;
585 
586 	KASSERT(td == curthread, ("uipc_connect: td != curthread"));
587 	UNP_LINK_WLOCK();
588 	error = unp_connect(so, nam, td);
589 	UNP_LINK_WUNLOCK();
590 	return (error);
591 }
592 
593 static int
594 uipc_connectat(int fd, struct socket *so, struct sockaddr *nam,
595     struct thread *td)
596 {
597 	int error;
598 
599 	KASSERT(td == curthread, ("uipc_connectat: td != curthread"));
600 	UNP_LINK_WLOCK();
601 	error = unp_connectat(fd, so, nam, td);
602 	UNP_LINK_WUNLOCK();
603 	return (error);
604 }
605 
606 static void
607 uipc_close(struct socket *so)
608 {
609 	struct unpcb *unp, *unp2;
610 
611 	unp = sotounpcb(so);
612 	KASSERT(unp != NULL, ("uipc_close: unp == NULL"));
613 
614 	UNP_LINK_WLOCK();
615 	UNP_PCB_LOCK(unp);
616 	unp2 = unp->unp_conn;
617 	if (unp2 != NULL) {
618 		UNP_PCB_LOCK(unp2);
619 		unp_disconnect(unp, unp2);
620 		UNP_PCB_UNLOCK(unp2);
621 	}
622 	UNP_PCB_UNLOCK(unp);
623 	UNP_LINK_WUNLOCK();
624 }
625 
626 static int
627 uipc_connect2(struct socket *so1, struct socket *so2)
628 {
629 	struct unpcb *unp, *unp2;
630 	int error;
631 
632 	UNP_LINK_WLOCK();
633 	unp = so1->so_pcb;
634 	KASSERT(unp != NULL, ("uipc_connect2: unp == NULL"));
635 	UNP_PCB_LOCK(unp);
636 	unp2 = so2->so_pcb;
637 	KASSERT(unp2 != NULL, ("uipc_connect2: unp2 == NULL"));
638 	UNP_PCB_LOCK(unp2);
639 	error = unp_connect2(so1, so2, PRU_CONNECT2);
640 	UNP_PCB_UNLOCK(unp2);
641 	UNP_PCB_UNLOCK(unp);
642 	UNP_LINK_WUNLOCK();
643 	return (error);
644 }
645 
646 static void
647 uipc_detach(struct socket *so)
648 {
649 	struct unpcb *unp, *unp2;
650 	struct sockaddr_un *saved_unp_addr;
651 	struct vnode *vp;
652 	int freeunp, local_unp_rights;
653 
654 	unp = sotounpcb(so);
655 	KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
656 
657 	vp = NULL;
658 	local_unp_rights = 0;
659 
660 	UNP_LIST_LOCK();
661 	LIST_REMOVE(unp, unp_link);
662 	unp->unp_gencnt = ++unp_gencnt;
663 	--unp_count;
664 	UNP_LIST_UNLOCK();
665 
666 	if ((unp->unp_flags & UNP_NASCENT) != 0) {
667 		UNP_PCB_LOCK(unp);
668 		goto teardown;
669 	}
670 	UNP_LINK_WLOCK();
671 	UNP_PCB_LOCK(unp);
672 
673 	/*
674 	 * XXXRW: Should assert vp->v_socket == so.
675 	 */
676 	if ((vp = unp->unp_vnode) != NULL) {
677 		VOP_UNP_DETACH(vp);
678 		unp->unp_vnode = NULL;
679 	}
680 	unp2 = unp->unp_conn;
681 	if (unp2 != NULL) {
682 		UNP_PCB_LOCK(unp2);
683 		unp_disconnect(unp, unp2);
684 		UNP_PCB_UNLOCK(unp2);
685 	}
686 
687 	/*
688 	 * We hold the linkage lock exclusively, so it's OK to acquire
689 	 * multiple pcb locks at a time.
690 	 */
691 	while (!LIST_EMPTY(&unp->unp_refs)) {
692 		struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
693 
694 		UNP_PCB_LOCK(ref);
695 		unp_drop(ref);
696 		UNP_PCB_UNLOCK(ref);
697 	}
698 	local_unp_rights = unp_rights;
699 	UNP_LINK_WUNLOCK();
700 teardown:
701 	unp->unp_socket->so_pcb = NULL;
702 	saved_unp_addr = unp->unp_addr;
703 	unp->unp_addr = NULL;
704 	unp->unp_refcount--;
705 	freeunp = (unp->unp_refcount == 0);
706 	if (saved_unp_addr != NULL)
707 		free(saved_unp_addr, M_SONAME);
708 	if (freeunp) {
709 		UNP_PCB_LOCK_DESTROY(unp);
710 		uma_zfree(unp_zone, unp);
711 	} else
712 		UNP_PCB_UNLOCK(unp);
713 	if (vp)
714 		vrele(vp);
715 	if (local_unp_rights)
716 		taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1);
717 }
718 
719 static int
720 uipc_disconnect(struct socket *so)
721 {
722 	struct unpcb *unp, *unp2;
723 
724 	unp = sotounpcb(so);
725 	KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
726 
727 	UNP_LINK_WLOCK();
728 	UNP_PCB_LOCK(unp);
729 	unp2 = unp->unp_conn;
730 	if (unp2 != NULL) {
731 		UNP_PCB_LOCK(unp2);
732 		unp_disconnect(unp, unp2);
733 		UNP_PCB_UNLOCK(unp2);
734 	}
735 	UNP_PCB_UNLOCK(unp);
736 	UNP_LINK_WUNLOCK();
737 	return (0);
738 }
739 
740 static int
741 uipc_listen(struct socket *so, int backlog, struct thread *td)
742 {
743 	struct unpcb *unp;
744 	int error;
745 
746 	unp = sotounpcb(so);
747 	KASSERT(unp != NULL, ("uipc_listen: unp == NULL"));
748 
749 	UNP_PCB_LOCK(unp);
750 	if (unp->unp_vnode == NULL) {
751 		/* Already connected or not bound to an address. */
752 		error = unp->unp_conn != NULL ? EINVAL : EDESTADDRREQ;
753 		UNP_PCB_UNLOCK(unp);
754 		return (error);
755 	}
756 
757 	SOCK_LOCK(so);
758 	error = solisten_proto_check(so);
759 	if (error == 0) {
760 		cru2x(td->td_ucred, &unp->unp_peercred);
761 		unp->unp_flags |= UNP_HAVEPCCACHED;
762 		solisten_proto(so, backlog);
763 	}
764 	SOCK_UNLOCK(so);
765 	UNP_PCB_UNLOCK(unp);
766 	return (error);
767 }
768 
769 static int
770 uipc_peeraddr(struct socket *so, struct sockaddr **nam)
771 {
772 	struct unpcb *unp, *unp2;
773 	const struct sockaddr *sa;
774 
775 	unp = sotounpcb(so);
776 	KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
777 
778 	*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
779 	UNP_LINK_RLOCK();
780 	/*
781 	 * XXX: It seems that this test always fails even when connection is
782 	 * established.  So, this else clause is added as workaround to
783 	 * return PF_LOCAL sockaddr.
784 	 */
785 	unp2 = unp->unp_conn;
786 	if (unp2 != NULL) {
787 		UNP_PCB_LOCK(unp2);
788 		if (unp2->unp_addr != NULL)
789 			sa = (struct sockaddr *) unp2->unp_addr;
790 		else
791 			sa = &sun_noname;
792 		bcopy(sa, *nam, sa->sa_len);
793 		UNP_PCB_UNLOCK(unp2);
794 	} else {
795 		sa = &sun_noname;
796 		bcopy(sa, *nam, sa->sa_len);
797 	}
798 	UNP_LINK_RUNLOCK();
799 	return (0);
800 }
801 
802 static int
803 uipc_rcvd(struct socket *so, int flags)
804 {
805 	struct unpcb *unp, *unp2;
806 	struct socket *so2;
807 	u_int mbcnt, sbcc;
808 
809 	unp = sotounpcb(so);
810 	KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
811 	KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
812 	    ("%s: socktype %d", __func__, so->so_type));
813 
814 	/*
815 	 * Adjust backpressure on sender and wakeup any waiting to write.
816 	 *
817 	 * The unp lock is acquired to maintain the validity of the unp_conn
818 	 * pointer; no lock on unp2 is required as unp2->unp_socket will be
819 	 * static as long as we don't permit unp2 to disconnect from unp,
820 	 * which is prevented by the lock on unp.  We cache values from
821 	 * so_rcv to avoid holding the so_rcv lock over the entire
822 	 * transaction on the remote so_snd.
823 	 */
824 	SOCKBUF_LOCK(&so->so_rcv);
825 	mbcnt = so->so_rcv.sb_mbcnt;
826 	sbcc = sbavail(&so->so_rcv);
827 	SOCKBUF_UNLOCK(&so->so_rcv);
828 	/*
829 	 * There is a benign race condition at this point.  If we're planning to
830 	 * clear SB_STOP, but uipc_send is called on the connected socket at
831 	 * this instant, it might add data to the sockbuf and set SB_STOP.  Then
832 	 * we would erroneously clear SB_STOP below, even though the sockbuf is
833 	 * full.  The race is benign because the only ill effect is to allow the
834 	 * sockbuf to exceed its size limit, and the size limits are not
835 	 * strictly guaranteed anyway.
836 	 */
837 	UNP_PCB_LOCK(unp);
838 	unp2 = unp->unp_conn;
839 	if (unp2 == NULL) {
840 		UNP_PCB_UNLOCK(unp);
841 		return (0);
842 	}
843 	so2 = unp2->unp_socket;
844 	SOCKBUF_LOCK(&so2->so_snd);
845 	if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax)
846 		so2->so_snd.sb_flags &= ~SB_STOP;
847 	sowwakeup_locked(so2);
848 	UNP_PCB_UNLOCK(unp);
849 	return (0);
850 }
851 
852 static int
853 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
854     struct mbuf *control, struct thread *td)
855 {
856 	struct unpcb *unp, *unp2;
857 	struct socket *so2;
858 	u_int mbcnt, sbcc;
859 	int error = 0;
860 
861 	unp = sotounpcb(so);
862 	KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
863 	KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_DGRAM ||
864 	    so->so_type == SOCK_SEQPACKET,
865 	    ("%s: socktype %d", __func__, so->so_type));
866 
867 	if (flags & PRUS_OOB) {
868 		error = EOPNOTSUPP;
869 		goto release;
870 	}
871 	if (control != NULL && (error = unp_internalize(&control, td)))
872 		goto release;
873 	if ((nam != NULL) || (flags & PRUS_EOF))
874 		UNP_LINK_WLOCK();
875 	else
876 		UNP_LINK_RLOCK();
877 	switch (so->so_type) {
878 	case SOCK_DGRAM:
879 	{
880 		const struct sockaddr *from;
881 
882 		unp2 = unp->unp_conn;
883 		if (nam != NULL) {
884 			UNP_LINK_WLOCK_ASSERT();
885 			if (unp2 != NULL) {
886 				error = EISCONN;
887 				break;
888 			}
889 			error = unp_connect(so, nam, td);
890 			if (error)
891 				break;
892 			unp2 = unp->unp_conn;
893 		}
894 
895 		/*
896 		 * Because connect() and send() are non-atomic in a sendto()
897 		 * with a target address, it's possible that the socket will
898 		 * have disconnected before the send() can run.  In that case
899 		 * return the slightly counter-intuitive but otherwise
900 		 * correct error that the socket is not connected.
901 		 */
902 		if (unp2 == NULL) {
903 			error = ENOTCONN;
904 			break;
905 		}
906 		/* Lockless read. */
907 		if (unp2->unp_flags & UNP_WANTCRED)
908 			control = unp_addsockcred(td, control);
909 		UNP_PCB_LOCK(unp);
910 		if (unp->unp_addr != NULL)
911 			from = (struct sockaddr *)unp->unp_addr;
912 		else
913 			from = &sun_noname;
914 		so2 = unp2->unp_socket;
915 		SOCKBUF_LOCK(&so2->so_rcv);
916 		if (sbappendaddr_locked(&so2->so_rcv, from, m,
917 		    control)) {
918 			sorwakeup_locked(so2);
919 			m = NULL;
920 			control = NULL;
921 		} else {
922 			SOCKBUF_UNLOCK(&so2->so_rcv);
923 			error = ENOBUFS;
924 		}
925 		if (nam != NULL) {
926 			UNP_LINK_WLOCK_ASSERT();
927 			UNP_PCB_LOCK(unp2);
928 			unp_disconnect(unp, unp2);
929 			UNP_PCB_UNLOCK(unp2);
930 		}
931 		UNP_PCB_UNLOCK(unp);
932 		break;
933 	}
934 
935 	case SOCK_SEQPACKET:
936 	case SOCK_STREAM:
937 		if ((so->so_state & SS_ISCONNECTED) == 0) {
938 			if (nam != NULL) {
939 				UNP_LINK_WLOCK_ASSERT();
940 				error = unp_connect(so, nam, td);
941 				if (error)
942 					break;	/* XXX */
943 			} else {
944 				error = ENOTCONN;
945 				break;
946 			}
947 		}
948 
949 		/* Lockless read. */
950 		if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
951 			error = EPIPE;
952 			break;
953 		}
954 
955 		/*
956 		 * Because connect() and send() are non-atomic in a sendto()
957 		 * with a target address, it's possible that the socket will
958 		 * have disconnected before the send() can run.  In that case
959 		 * return the slightly counter-intuitive but otherwise
960 		 * correct error that the socket is not connected.
961 		 *
962 		 * Locking here must be done carefully: the linkage lock
963 		 * prevents interconnections between unpcbs from changing, so
964 		 * we can traverse from unp to unp2 without acquiring unp's
965 		 * lock.  Socket buffer locks follow unpcb locks, so we can
966 		 * acquire both remote and lock socket buffer locks.
967 		 */
968 		unp2 = unp->unp_conn;
969 		if (unp2 == NULL) {
970 			error = ENOTCONN;
971 			break;
972 		}
973 		so2 = unp2->unp_socket;
974 		UNP_PCB_LOCK(unp2);
975 		SOCKBUF_LOCK(&so2->so_rcv);
976 		if (unp2->unp_flags & UNP_WANTCRED) {
977 			/*
978 			 * Credentials are passed only once on SOCK_STREAM
979 			 * and SOCK_SEQPACKET.
980 			 */
981 			unp2->unp_flags &= ~UNP_WANTCRED;
982 			control = unp_addsockcred(td, control);
983 		}
984 		/*
985 		 * Send to paired receive port, and then reduce send buffer
986 		 * hiwater marks to maintain backpressure.  Wake up readers.
987 		 */
988 		switch (so->so_type) {
989 		case SOCK_STREAM:
990 			if (control != NULL) {
991 				if (sbappendcontrol_locked(&so2->so_rcv, m,
992 				    control))
993 					control = NULL;
994 			} else
995 				sbappend_locked(&so2->so_rcv, m, flags);
996 			break;
997 
998 		case SOCK_SEQPACKET: {
999 			const struct sockaddr *from;
1000 
1001 			from = &sun_noname;
1002 			/*
1003 			 * Don't check for space available in so2->so_rcv.
1004 			 * Unix domain sockets only check for space in the
1005 			 * sending sockbuf, and that check is performed one
1006 			 * level up the stack.
1007 			 */
1008 			if (sbappendaddr_nospacecheck_locked(&so2->so_rcv,
1009 				from, m, control))
1010 				control = NULL;
1011 			break;
1012 			}
1013 		}
1014 
1015 		mbcnt = so2->so_rcv.sb_mbcnt;
1016 		sbcc = sbavail(&so2->so_rcv);
1017 		if (sbcc)
1018 			sorwakeup_locked(so2);
1019 		else
1020 			SOCKBUF_UNLOCK(&so2->so_rcv);
1021 
1022 		/*
1023 		 * The PCB lock on unp2 protects the SB_STOP flag.  Without it,
1024 		 * it would be possible for uipc_rcvd to be called at this
1025 		 * point, drain the receiving sockbuf, clear SB_STOP, and then
1026 		 * we would set SB_STOP below.  That could lead to an empty
1027 		 * sockbuf having SB_STOP set
1028 		 */
1029 		SOCKBUF_LOCK(&so->so_snd);
1030 		if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax)
1031 			so->so_snd.sb_flags |= SB_STOP;
1032 		SOCKBUF_UNLOCK(&so->so_snd);
1033 		UNP_PCB_UNLOCK(unp2);
1034 		m = NULL;
1035 		break;
1036 	}
1037 
1038 	/*
1039 	 * PRUS_EOF is equivalent to pru_send followed by pru_shutdown.
1040 	 */
1041 	if (flags & PRUS_EOF) {
1042 		UNP_PCB_LOCK(unp);
1043 		socantsendmore(so);
1044 		unp_shutdown(unp);
1045 		UNP_PCB_UNLOCK(unp);
1046 	}
1047 
1048 	if ((nam != NULL) || (flags & PRUS_EOF))
1049 		UNP_LINK_WUNLOCK();
1050 	else
1051 		UNP_LINK_RUNLOCK();
1052 
1053 	if (control != NULL && error != 0)
1054 		unp_dispose_mbuf(control);
1055 
1056 release:
1057 	if (control != NULL)
1058 		m_freem(control);
1059 	if (m != NULL)
1060 		m_freem(m);
1061 	return (error);
1062 }
1063 
1064 static int
1065 uipc_ready(struct socket *so, struct mbuf *m, int count)
1066 {
1067 	struct unpcb *unp, *unp2;
1068 	struct socket *so2;
1069 	int error;
1070 
1071 	unp = sotounpcb(so);
1072 
1073 	UNP_LINK_RLOCK();
1074 	unp2 = unp->unp_conn;
1075 	UNP_PCB_LOCK(unp2);
1076 	so2 = unp2->unp_socket;
1077 
1078 	SOCKBUF_LOCK(&so2->so_rcv);
1079 	if ((error = sbready(&so2->so_rcv, m, count)) == 0)
1080 		sorwakeup_locked(so2);
1081 	else
1082 		SOCKBUF_UNLOCK(&so2->so_rcv);
1083 
1084 	UNP_PCB_UNLOCK(unp2);
1085 	UNP_LINK_RUNLOCK();
1086 
1087 	return (error);
1088 }
1089 
1090 static int
1091 uipc_sense(struct socket *so, struct stat *sb)
1092 {
1093 	struct unpcb *unp;
1094 
1095 	unp = sotounpcb(so);
1096 	KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
1097 
1098 	sb->st_blksize = so->so_snd.sb_hiwat;
1099 	UNP_PCB_LOCK(unp);
1100 	sb->st_dev = NODEV;
1101 	if (unp->unp_ino == 0)
1102 		unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
1103 	sb->st_ino = unp->unp_ino;
1104 	UNP_PCB_UNLOCK(unp);
1105 	return (0);
1106 }
1107 
1108 static int
1109 uipc_shutdown(struct socket *so)
1110 {
1111 	struct unpcb *unp;
1112 
1113 	unp = sotounpcb(so);
1114 	KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
1115 
1116 	UNP_LINK_WLOCK();
1117 	UNP_PCB_LOCK(unp);
1118 	socantsendmore(so);
1119 	unp_shutdown(unp);
1120 	UNP_PCB_UNLOCK(unp);
1121 	UNP_LINK_WUNLOCK();
1122 	return (0);
1123 }
1124 
1125 static int
1126 uipc_sockaddr(struct socket *so, struct sockaddr **nam)
1127 {
1128 	struct unpcb *unp;
1129 	const struct sockaddr *sa;
1130 
1131 	unp = sotounpcb(so);
1132 	KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
1133 
1134 	*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1135 	UNP_PCB_LOCK(unp);
1136 	if (unp->unp_addr != NULL)
1137 		sa = (struct sockaddr *) unp->unp_addr;
1138 	else
1139 		sa = &sun_noname;
1140 	bcopy(sa, *nam, sa->sa_len);
1141 	UNP_PCB_UNLOCK(unp);
1142 	return (0);
1143 }
1144 
1145 static struct pr_usrreqs uipc_usrreqs_dgram = {
1146 	.pru_abort = 		uipc_abort,
1147 	.pru_accept =		uipc_accept,
1148 	.pru_attach =		uipc_attach,
1149 	.pru_bind =		uipc_bind,
1150 	.pru_bindat =		uipc_bindat,
1151 	.pru_connect =		uipc_connect,
1152 	.pru_connectat =	uipc_connectat,
1153 	.pru_connect2 =		uipc_connect2,
1154 	.pru_detach =		uipc_detach,
1155 	.pru_disconnect =	uipc_disconnect,
1156 	.pru_listen =		uipc_listen,
1157 	.pru_peeraddr =		uipc_peeraddr,
1158 	.pru_rcvd =		uipc_rcvd,
1159 	.pru_send =		uipc_send,
1160 	.pru_sense =		uipc_sense,
1161 	.pru_shutdown =		uipc_shutdown,
1162 	.pru_sockaddr =		uipc_sockaddr,
1163 	.pru_soreceive =	soreceive_dgram,
1164 	.pru_close =		uipc_close,
1165 };
1166 
1167 static struct pr_usrreqs uipc_usrreqs_seqpacket = {
1168 	.pru_abort =		uipc_abort,
1169 	.pru_accept =		uipc_accept,
1170 	.pru_attach =		uipc_attach,
1171 	.pru_bind =		uipc_bind,
1172 	.pru_bindat =		uipc_bindat,
1173 	.pru_connect =		uipc_connect,
1174 	.pru_connectat =	uipc_connectat,
1175 	.pru_connect2 =		uipc_connect2,
1176 	.pru_detach =		uipc_detach,
1177 	.pru_disconnect =	uipc_disconnect,
1178 	.pru_listen =		uipc_listen,
1179 	.pru_peeraddr =		uipc_peeraddr,
1180 	.pru_rcvd =		uipc_rcvd,
1181 	.pru_send =		uipc_send,
1182 	.pru_sense =		uipc_sense,
1183 	.pru_shutdown =		uipc_shutdown,
1184 	.pru_sockaddr =		uipc_sockaddr,
1185 	.pru_soreceive =	soreceive_generic,	/* XXX: or...? */
1186 	.pru_close =		uipc_close,
1187 };
1188 
1189 static struct pr_usrreqs uipc_usrreqs_stream = {
1190 	.pru_abort = 		uipc_abort,
1191 	.pru_accept =		uipc_accept,
1192 	.pru_attach =		uipc_attach,
1193 	.pru_bind =		uipc_bind,
1194 	.pru_bindat =		uipc_bindat,
1195 	.pru_connect =		uipc_connect,
1196 	.pru_connectat =	uipc_connectat,
1197 	.pru_connect2 =		uipc_connect2,
1198 	.pru_detach =		uipc_detach,
1199 	.pru_disconnect =	uipc_disconnect,
1200 	.pru_listen =		uipc_listen,
1201 	.pru_peeraddr =		uipc_peeraddr,
1202 	.pru_rcvd =		uipc_rcvd,
1203 	.pru_send =		uipc_send,
1204 	.pru_ready =		uipc_ready,
1205 	.pru_sense =		uipc_sense,
1206 	.pru_shutdown =		uipc_shutdown,
1207 	.pru_sockaddr =		uipc_sockaddr,
1208 	.pru_soreceive =	soreceive_generic,
1209 	.pru_close =		uipc_close,
1210 };
1211 
1212 static int
1213 uipc_ctloutput(struct socket *so, struct sockopt *sopt)
1214 {
1215 	struct unpcb *unp;
1216 	struct xucred xu;
1217 	int error, optval;
1218 
1219 	if (sopt->sopt_level != 0)
1220 		return (EINVAL);
1221 
1222 	unp = sotounpcb(so);
1223 	KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
1224 	error = 0;
1225 	switch (sopt->sopt_dir) {
1226 	case SOPT_GET:
1227 		switch (sopt->sopt_name) {
1228 		case LOCAL_PEERCRED:
1229 			UNP_PCB_LOCK(unp);
1230 			if (unp->unp_flags & UNP_HAVEPC)
1231 				xu = unp->unp_peercred;
1232 			else {
1233 				if (so->so_type == SOCK_STREAM)
1234 					error = ENOTCONN;
1235 				else
1236 					error = EINVAL;
1237 			}
1238 			UNP_PCB_UNLOCK(unp);
1239 			if (error == 0)
1240 				error = sooptcopyout(sopt, &xu, sizeof(xu));
1241 			break;
1242 
1243 		case LOCAL_CREDS:
1244 			/* Unlocked read. */
1245 			optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
1246 			error = sooptcopyout(sopt, &optval, sizeof(optval));
1247 			break;
1248 
1249 		case LOCAL_CONNWAIT:
1250 			/* Unlocked read. */
1251 			optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
1252 			error = sooptcopyout(sopt, &optval, sizeof(optval));
1253 			break;
1254 
1255 		default:
1256 			error = EOPNOTSUPP;
1257 			break;
1258 		}
1259 		break;
1260 
1261 	case SOPT_SET:
1262 		switch (sopt->sopt_name) {
1263 		case LOCAL_CREDS:
1264 		case LOCAL_CONNWAIT:
1265 			error = sooptcopyin(sopt, &optval, sizeof(optval),
1266 					    sizeof(optval));
1267 			if (error)
1268 				break;
1269 
1270 #define	OPTSET(bit) do {						\
1271 	UNP_PCB_LOCK(unp);						\
1272 	if (optval)							\
1273 		unp->unp_flags |= bit;					\
1274 	else								\
1275 		unp->unp_flags &= ~bit;					\
1276 	UNP_PCB_UNLOCK(unp);						\
1277 } while (0)
1278 
1279 			switch (sopt->sopt_name) {
1280 			case LOCAL_CREDS:
1281 				OPTSET(UNP_WANTCRED);
1282 				break;
1283 
1284 			case LOCAL_CONNWAIT:
1285 				OPTSET(UNP_CONNWAIT);
1286 				break;
1287 
1288 			default:
1289 				break;
1290 			}
1291 			break;
1292 #undef	OPTSET
1293 		default:
1294 			error = ENOPROTOOPT;
1295 			break;
1296 		}
1297 		break;
1298 
1299 	default:
1300 		error = EOPNOTSUPP;
1301 		break;
1302 	}
1303 	return (error);
1304 }
1305 
1306 static int
1307 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1308 {
1309 
1310 	return (unp_connectat(AT_FDCWD, so, nam, td));
1311 }
1312 
1313 static int
1314 unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
1315     struct thread *td)
1316 {
1317 	struct sockaddr_un *soun = (struct sockaddr_un *)nam;
1318 	struct vnode *vp;
1319 	struct socket *so2, *so3;
1320 	struct unpcb *unp, *unp2, *unp3;
1321 	struct nameidata nd;
1322 	char buf[SOCK_MAXADDRLEN];
1323 	struct sockaddr *sa;
1324 	cap_rights_t rights;
1325 	int error, len;
1326 
1327 	if (nam->sa_family != AF_UNIX)
1328 		return (EAFNOSUPPORT);
1329 
1330 	UNP_LINK_WLOCK_ASSERT();
1331 
1332 	unp = sotounpcb(so);
1333 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1334 
1335 	if (nam->sa_len > sizeof(struct sockaddr_un))
1336 		return (EINVAL);
1337 	len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
1338 	if (len <= 0)
1339 		return (EINVAL);
1340 	bcopy(soun->sun_path, buf, len);
1341 	buf[len] = 0;
1342 
1343 	UNP_PCB_LOCK(unp);
1344 	if (unp->unp_flags & UNP_CONNECTING) {
1345 		UNP_PCB_UNLOCK(unp);
1346 		return (EALREADY);
1347 	}
1348 	UNP_LINK_WUNLOCK();
1349 	unp->unp_flags |= UNP_CONNECTING;
1350 	UNP_PCB_UNLOCK(unp);
1351 
1352 	sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1353 	NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
1354 	    UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_CONNECTAT), td);
1355 	error = namei(&nd);
1356 	if (error)
1357 		vp = NULL;
1358 	else
1359 		vp = nd.ni_vp;
1360 	ASSERT_VOP_LOCKED(vp, "unp_connect");
1361 	NDFREE(&nd, NDF_ONLY_PNBUF);
1362 	if (error)
1363 		goto bad;
1364 
1365 	if (vp->v_type != VSOCK) {
1366 		error = ENOTSOCK;
1367 		goto bad;
1368 	}
1369 #ifdef MAC
1370 	error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD);
1371 	if (error)
1372 		goto bad;
1373 #endif
1374 	error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
1375 	if (error)
1376 		goto bad;
1377 
1378 	unp = sotounpcb(so);
1379 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1380 
1381 	/*
1382 	 * Lock linkage lock for two reasons: make sure v_socket is stable,
1383 	 * and to protect simultaneous locking of multiple pcbs.
1384 	 */
1385 	UNP_LINK_WLOCK();
1386 	VOP_UNP_CONNECT(vp, &so2);
1387 	if (so2 == NULL) {
1388 		error = ECONNREFUSED;
1389 		goto bad2;
1390 	}
1391 	if (so->so_type != so2->so_type) {
1392 		error = EPROTOTYPE;
1393 		goto bad2;
1394 	}
1395 	if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
1396 		if (so2->so_options & SO_ACCEPTCONN) {
1397 			CURVNET_SET(so2->so_vnet);
1398 			so3 = sonewconn(so2, 0);
1399 			CURVNET_RESTORE();
1400 		} else
1401 			so3 = NULL;
1402 		if (so3 == NULL) {
1403 			error = ECONNREFUSED;
1404 			goto bad2;
1405 		}
1406 		unp = sotounpcb(so);
1407 		unp2 = sotounpcb(so2);
1408 		unp3 = sotounpcb(so3);
1409 		UNP_PCB_LOCK(unp);
1410 		UNP_PCB_LOCK(unp2);
1411 		UNP_PCB_LOCK(unp3);
1412 		if (unp2->unp_addr != NULL) {
1413 			bcopy(unp2->unp_addr, sa, unp2->unp_addr->sun_len);
1414 			unp3->unp_addr = (struct sockaddr_un *) sa;
1415 			sa = NULL;
1416 		}
1417 
1418 		/*
1419 		 * The connector's (client's) credentials are copied from its
1420 		 * process structure at the time of connect() (which is now).
1421 		 */
1422 		cru2x(td->td_ucred, &unp3->unp_peercred);
1423 		unp3->unp_flags |= UNP_HAVEPC;
1424 
1425 		/*
1426 		 * The receiver's (server's) credentials are copied from the
1427 		 * unp_peercred member of socket on which the former called
1428 		 * listen(); uipc_listen() cached that process's credentials
1429 		 * at that time so we can use them now.
1430 		 */
1431 		KASSERT(unp2->unp_flags & UNP_HAVEPCCACHED,
1432 		    ("unp_connect: listener without cached peercred"));
1433 		memcpy(&unp->unp_peercred, &unp2->unp_peercred,
1434 		    sizeof(unp->unp_peercred));
1435 		unp->unp_flags |= UNP_HAVEPC;
1436 		if (unp2->unp_flags & UNP_WANTCRED)
1437 			unp3->unp_flags |= UNP_WANTCRED;
1438 		UNP_PCB_UNLOCK(unp3);
1439 		UNP_PCB_UNLOCK(unp2);
1440 		UNP_PCB_UNLOCK(unp);
1441 #ifdef MAC
1442 		mac_socketpeer_set_from_socket(so, so3);
1443 		mac_socketpeer_set_from_socket(so3, so);
1444 #endif
1445 
1446 		so2 = so3;
1447 	}
1448 	unp = sotounpcb(so);
1449 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1450 	unp2 = sotounpcb(so2);
1451 	KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL"));
1452 	UNP_PCB_LOCK(unp);
1453 	UNP_PCB_LOCK(unp2);
1454 	error = unp_connect2(so, so2, PRU_CONNECT);
1455 	UNP_PCB_UNLOCK(unp2);
1456 	UNP_PCB_UNLOCK(unp);
1457 bad2:
1458 	UNP_LINK_WUNLOCK();
1459 bad:
1460 	if (vp != NULL)
1461 		vput(vp);
1462 	free(sa, M_SONAME);
1463 	UNP_LINK_WLOCK();
1464 	UNP_PCB_LOCK(unp);
1465 	unp->unp_flags &= ~UNP_CONNECTING;
1466 	UNP_PCB_UNLOCK(unp);
1467 	return (error);
1468 }
1469 
1470 static int
1471 unp_connect2(struct socket *so, struct socket *so2, int req)
1472 {
1473 	struct unpcb *unp;
1474 	struct unpcb *unp2;
1475 
1476 	unp = sotounpcb(so);
1477 	KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
1478 	unp2 = sotounpcb(so2);
1479 	KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
1480 
1481 	UNP_LINK_WLOCK_ASSERT();
1482 	UNP_PCB_LOCK_ASSERT(unp);
1483 	UNP_PCB_LOCK_ASSERT(unp2);
1484 
1485 	if (so2->so_type != so->so_type)
1486 		return (EPROTOTYPE);
1487 	unp2->unp_flags &= ~UNP_NASCENT;
1488 	unp->unp_conn = unp2;
1489 
1490 	switch (so->so_type) {
1491 	case SOCK_DGRAM:
1492 		LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
1493 		soisconnected(so);
1494 		break;
1495 
1496 	case SOCK_STREAM:
1497 	case SOCK_SEQPACKET:
1498 		unp2->unp_conn = unp;
1499 		if (req == PRU_CONNECT &&
1500 		    ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
1501 			soisconnecting(so);
1502 		else
1503 			soisconnected(so);
1504 		soisconnected(so2);
1505 		break;
1506 
1507 	default:
1508 		panic("unp_connect2");
1509 	}
1510 	return (0);
1511 }
1512 
1513 static void
1514 unp_disconnect(struct unpcb *unp, struct unpcb *unp2)
1515 {
1516 	struct socket *so;
1517 
1518 	KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
1519 
1520 	UNP_LINK_WLOCK_ASSERT();
1521 	UNP_PCB_LOCK_ASSERT(unp);
1522 	UNP_PCB_LOCK_ASSERT(unp2);
1523 
1524 	unp->unp_conn = NULL;
1525 	switch (unp->unp_socket->so_type) {
1526 	case SOCK_DGRAM:
1527 		LIST_REMOVE(unp, unp_reflink);
1528 		so = unp->unp_socket;
1529 		SOCK_LOCK(so);
1530 		so->so_state &= ~SS_ISCONNECTED;
1531 		SOCK_UNLOCK(so);
1532 		break;
1533 
1534 	case SOCK_STREAM:
1535 	case SOCK_SEQPACKET:
1536 		soisdisconnected(unp->unp_socket);
1537 		unp2->unp_conn = NULL;
1538 		soisdisconnected(unp2->unp_socket);
1539 		break;
1540 	}
1541 }
1542 
1543 /*
1544  * unp_pcblist() walks the global list of struct unpcb's to generate a
1545  * pointer list, bumping the refcount on each unpcb.  It then copies them out
1546  * sequentially, validating the generation number on each to see if it has
1547  * been detached.  All of this is necessary because copyout() may sleep on
1548  * disk I/O.
1549  */
1550 static int
1551 unp_pcblist(SYSCTL_HANDLER_ARGS)
1552 {
1553 	int error, i, n;
1554 	int freeunp;
1555 	struct unpcb *unp, **unp_list;
1556 	unp_gen_t gencnt;
1557 	struct xunpgen *xug;
1558 	struct unp_head *head;
1559 	struct xunpcb *xu;
1560 
1561 	switch ((intptr_t)arg1) {
1562 	case SOCK_STREAM:
1563 		head = &unp_shead;
1564 		break;
1565 
1566 	case SOCK_DGRAM:
1567 		head = &unp_dhead;
1568 		break;
1569 
1570 	case SOCK_SEQPACKET:
1571 		head = &unp_sphead;
1572 		break;
1573 
1574 	default:
1575 		panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1);
1576 	}
1577 
1578 	/*
1579 	 * The process of preparing the PCB list is too time-consuming and
1580 	 * resource-intensive to repeat twice on every request.
1581 	 */
1582 	if (req->oldptr == NULL) {
1583 		n = unp_count;
1584 		req->oldidx = 2 * (sizeof *xug)
1585 			+ (n + n/8) * sizeof(struct xunpcb);
1586 		return (0);
1587 	}
1588 
1589 	if (req->newptr != NULL)
1590 		return (EPERM);
1591 
1592 	/*
1593 	 * OK, now we're committed to doing something.
1594 	 */
1595 	xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK);
1596 	UNP_LIST_LOCK();
1597 	gencnt = unp_gencnt;
1598 	n = unp_count;
1599 	UNP_LIST_UNLOCK();
1600 
1601 	xug->xug_len = sizeof *xug;
1602 	xug->xug_count = n;
1603 	xug->xug_gen = gencnt;
1604 	xug->xug_sogen = so_gencnt;
1605 	error = SYSCTL_OUT(req, xug, sizeof *xug);
1606 	if (error) {
1607 		free(xug, M_TEMP);
1608 		return (error);
1609 	}
1610 
1611 	unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
1612 
1613 	UNP_LIST_LOCK();
1614 	for (unp = LIST_FIRST(head), i = 0; unp && i < n;
1615 	     unp = LIST_NEXT(unp, unp_link)) {
1616 		UNP_PCB_LOCK(unp);
1617 		if (unp->unp_gencnt <= gencnt) {
1618 			if (cr_cansee(req->td->td_ucred,
1619 			    unp->unp_socket->so_cred)) {
1620 				UNP_PCB_UNLOCK(unp);
1621 				continue;
1622 			}
1623 			unp_list[i++] = unp;
1624 			unp->unp_refcount++;
1625 		}
1626 		UNP_PCB_UNLOCK(unp);
1627 	}
1628 	UNP_LIST_UNLOCK();
1629 	n = i;			/* In case we lost some during malloc. */
1630 
1631 	error = 0;
1632 	xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
1633 	for (i = 0; i < n; i++) {
1634 		unp = unp_list[i];
1635 		UNP_PCB_LOCK(unp);
1636 		unp->unp_refcount--;
1637 	        if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) {
1638 			xu->xu_len = sizeof *xu;
1639 			xu->xu_unpp = unp;
1640 			/*
1641 			 * XXX - need more locking here to protect against
1642 			 * connect/disconnect races for SMP.
1643 			 */
1644 			if (unp->unp_addr != NULL)
1645 				bcopy(unp->unp_addr, &xu->xu_addr,
1646 				      unp->unp_addr->sun_len);
1647 			if (unp->unp_conn != NULL &&
1648 			    unp->unp_conn->unp_addr != NULL)
1649 				bcopy(unp->unp_conn->unp_addr,
1650 				      &xu->xu_caddr,
1651 				      unp->unp_conn->unp_addr->sun_len);
1652 			bcopy(unp, &xu->xu_unp, sizeof *unp);
1653 			sotoxsocket(unp->unp_socket, &xu->xu_socket);
1654 			UNP_PCB_UNLOCK(unp);
1655 			error = SYSCTL_OUT(req, xu, sizeof *xu);
1656 		} else {
1657 			freeunp = (unp->unp_refcount == 0);
1658 			UNP_PCB_UNLOCK(unp);
1659 			if (freeunp) {
1660 				UNP_PCB_LOCK_DESTROY(unp);
1661 				uma_zfree(unp_zone, unp);
1662 			}
1663 		}
1664 	}
1665 	free(xu, M_TEMP);
1666 	if (!error) {
1667 		/*
1668 		 * Give the user an updated idea of our state.  If the
1669 		 * generation differs from what we told her before, she knows
1670 		 * that something happened while we were processing this
1671 		 * request, and it might be necessary to retry.
1672 		 */
1673 		xug->xug_gen = unp_gencnt;
1674 		xug->xug_sogen = so_gencnt;
1675 		xug->xug_count = unp_count;
1676 		error = SYSCTL_OUT(req, xug, sizeof *xug);
1677 	}
1678 	free(unp_list, M_TEMP);
1679 	free(xug, M_TEMP);
1680 	return (error);
1681 }
1682 
1683 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1684     (void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
1685     "List of active local datagram sockets");
1686 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1687     (void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
1688     "List of active local stream sockets");
1689 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist,
1690     CTLTYPE_OPAQUE | CTLFLAG_RD,
1691     (void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb",
1692     "List of active local seqpacket sockets");
1693 
1694 static void
1695 unp_shutdown(struct unpcb *unp)
1696 {
1697 	struct unpcb *unp2;
1698 	struct socket *so;
1699 
1700 	UNP_LINK_WLOCK_ASSERT();
1701 	UNP_PCB_LOCK_ASSERT(unp);
1702 
1703 	unp2 = unp->unp_conn;
1704 	if ((unp->unp_socket->so_type == SOCK_STREAM ||
1705 	    (unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) {
1706 		so = unp2->unp_socket;
1707 		if (so != NULL)
1708 			socantrcvmore(so);
1709 	}
1710 }
1711 
1712 static void
1713 unp_drop(struct unpcb *unp)
1714 {
1715 	struct socket *so = unp->unp_socket;
1716 	struct unpcb *unp2;
1717 
1718 	UNP_LINK_WLOCK_ASSERT();
1719 	UNP_PCB_LOCK_ASSERT(unp);
1720 
1721 	/*
1722 	 * Regardless of whether the socket's peer dropped the connection
1723 	 * with this socket by aborting or disconnecting, POSIX requires
1724 	 * that ECONNRESET is returned.
1725 	 */
1726 	so->so_error = ECONNRESET;
1727 	unp2 = unp->unp_conn;
1728 	if (unp2 == NULL)
1729 		return;
1730 	UNP_PCB_LOCK(unp2);
1731 	unp_disconnect(unp, unp2);
1732 	UNP_PCB_UNLOCK(unp2);
1733 }
1734 
1735 static void
1736 unp_freerights(struct filedescent **fdep, int fdcount)
1737 {
1738 	struct file *fp;
1739 	int i;
1740 
1741 	KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount));
1742 
1743 	for (i = 0; i < fdcount; i++) {
1744 		fp = fdep[i]->fde_file;
1745 		filecaps_free(&fdep[i]->fde_caps);
1746 		unp_discard(fp);
1747 	}
1748 	free(fdep[0], M_FILECAPS);
1749 }
1750 
1751 static int
1752 unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
1753 {
1754 	struct thread *td = curthread;		/* XXX */
1755 	struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1756 	int i;
1757 	int *fdp;
1758 	struct filedesc *fdesc = td->td_proc->p_fd;
1759 	struct filedescent **fdep;
1760 	void *data;
1761 	socklen_t clen = control->m_len, datalen;
1762 	int error, newfds;
1763 	u_int newlen;
1764 
1765 	UNP_LINK_UNLOCK_ASSERT();
1766 
1767 	error = 0;
1768 	if (controlp != NULL) /* controlp == NULL => free control messages */
1769 		*controlp = NULL;
1770 	while (cm != NULL) {
1771 		if (sizeof(*cm) > clen || cm->cmsg_len > clen) {
1772 			error = EINVAL;
1773 			break;
1774 		}
1775 		data = CMSG_DATA(cm);
1776 		datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1777 		if (cm->cmsg_level == SOL_SOCKET
1778 		    && cm->cmsg_type == SCM_RIGHTS) {
1779 			newfds = datalen / sizeof(*fdep);
1780 			if (newfds == 0)
1781 				goto next;
1782 			fdep = data;
1783 
1784 			/* If we're not outputting the descriptors free them. */
1785 			if (error || controlp == NULL) {
1786 				unp_freerights(fdep, newfds);
1787 				goto next;
1788 			}
1789 			FILEDESC_XLOCK(fdesc);
1790 
1791 			/*
1792 			 * Now change each pointer to an fd in the global
1793 			 * table to an integer that is the index to the local
1794 			 * fd table entry that we set up to point to the
1795 			 * global one we are transferring.
1796 			 */
1797 			newlen = newfds * sizeof(int);
1798 			*controlp = sbcreatecontrol(NULL, newlen,
1799 			    SCM_RIGHTS, SOL_SOCKET);
1800 			if (*controlp == NULL) {
1801 				FILEDESC_XUNLOCK(fdesc);
1802 				error = E2BIG;
1803 				unp_freerights(fdep, newfds);
1804 				goto next;
1805 			}
1806 
1807 			fdp = (int *)
1808 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1809 			if (fdallocn(td, 0, fdp, newfds) != 0) {
1810 				FILEDESC_XUNLOCK(fdesc);
1811 				error = EMSGSIZE;
1812 				unp_freerights(fdep, newfds);
1813 				m_freem(*controlp);
1814 				*controlp = NULL;
1815 				goto next;
1816 			}
1817 			for (i = 0; i < newfds; i++, fdp++) {
1818 				_finstall(fdesc, fdep[i]->fde_file, *fdp,
1819 				    (flags & MSG_CMSG_CLOEXEC) != 0 ? UF_EXCLOSE : 0,
1820 				    &fdep[i]->fde_caps);
1821 				unp_externalize_fp(fdep[i]->fde_file);
1822 			}
1823 			FILEDESC_XUNLOCK(fdesc);
1824 			free(fdep[0], M_FILECAPS);
1825 		} else {
1826 			/* We can just copy anything else across. */
1827 			if (error || controlp == NULL)
1828 				goto next;
1829 			*controlp = sbcreatecontrol(NULL, datalen,
1830 			    cm->cmsg_type, cm->cmsg_level);
1831 			if (*controlp == NULL) {
1832 				error = ENOBUFS;
1833 				goto next;
1834 			}
1835 			bcopy(data,
1836 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
1837 			    datalen);
1838 		}
1839 		controlp = &(*controlp)->m_next;
1840 
1841 next:
1842 		if (CMSG_SPACE(datalen) < clen) {
1843 			clen -= CMSG_SPACE(datalen);
1844 			cm = (struct cmsghdr *)
1845 			    ((caddr_t)cm + CMSG_SPACE(datalen));
1846 		} else {
1847 			clen = 0;
1848 			cm = NULL;
1849 		}
1850 	}
1851 
1852 	m_freem(control);
1853 	return (error);
1854 }
1855 
1856 static void
1857 unp_zone_change(void *tag)
1858 {
1859 
1860 	uma_zone_set_max(unp_zone, maxsockets);
1861 }
1862 
1863 static void
1864 unp_init(void)
1865 {
1866 
1867 #ifdef VIMAGE
1868 	if (!IS_DEFAULT_VNET(curvnet))
1869 		return;
1870 #endif
1871 	unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
1872 	    NULL, NULL, UMA_ALIGN_PTR, 0);
1873 	if (unp_zone == NULL)
1874 		panic("unp_init");
1875 	uma_zone_set_max(unp_zone, maxsockets);
1876 	uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached");
1877 	EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
1878 	    NULL, EVENTHANDLER_PRI_ANY);
1879 	LIST_INIT(&unp_dhead);
1880 	LIST_INIT(&unp_shead);
1881 	LIST_INIT(&unp_sphead);
1882 	SLIST_INIT(&unp_defers);
1883 	TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL);
1884 	TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
1885 	UNP_LINK_LOCK_INIT();
1886 	UNP_LIST_LOCK_INIT();
1887 	UNP_DEFERRED_LOCK_INIT();
1888 }
1889 
1890 static int
1891 unp_internalize(struct mbuf **controlp, struct thread *td)
1892 {
1893 	struct mbuf *control = *controlp;
1894 	struct proc *p = td->td_proc;
1895 	struct filedesc *fdesc = p->p_fd;
1896 	struct bintime *bt;
1897 	struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1898 	struct cmsgcred *cmcred;
1899 	struct filedescent *fde, **fdep, *fdev;
1900 	struct file *fp;
1901 	struct timeval *tv;
1902 	int i, *fdp;
1903 	void *data;
1904 	socklen_t clen = control->m_len, datalen;
1905 	int error, oldfds;
1906 	u_int newlen;
1907 
1908 	UNP_LINK_UNLOCK_ASSERT();
1909 
1910 	error = 0;
1911 	*controlp = NULL;
1912 	while (cm != NULL) {
1913 		if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
1914 		    || cm->cmsg_len > clen || cm->cmsg_len < sizeof(*cm)) {
1915 			error = EINVAL;
1916 			goto out;
1917 		}
1918 		data = CMSG_DATA(cm);
1919 		datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1920 
1921 		switch (cm->cmsg_type) {
1922 		/*
1923 		 * Fill in credential information.
1924 		 */
1925 		case SCM_CREDS:
1926 			*controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
1927 			    SCM_CREDS, SOL_SOCKET);
1928 			if (*controlp == NULL) {
1929 				error = ENOBUFS;
1930 				goto out;
1931 			}
1932 			cmcred = (struct cmsgcred *)
1933 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1934 			cmcred->cmcred_pid = p->p_pid;
1935 			cmcred->cmcred_uid = td->td_ucred->cr_ruid;
1936 			cmcred->cmcred_gid = td->td_ucred->cr_rgid;
1937 			cmcred->cmcred_euid = td->td_ucred->cr_uid;
1938 			cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
1939 			    CMGROUP_MAX);
1940 			for (i = 0; i < cmcred->cmcred_ngroups; i++)
1941 				cmcred->cmcred_groups[i] =
1942 				    td->td_ucred->cr_groups[i];
1943 			break;
1944 
1945 		case SCM_RIGHTS:
1946 			oldfds = datalen / sizeof (int);
1947 			if (oldfds == 0)
1948 				break;
1949 			/*
1950 			 * Check that all the FDs passed in refer to legal
1951 			 * files.  If not, reject the entire operation.
1952 			 */
1953 			fdp = data;
1954 			FILEDESC_SLOCK(fdesc);
1955 			for (i = 0; i < oldfds; i++, fdp++) {
1956 				fp = fget_locked(fdesc, *fdp);
1957 				if (fp == NULL) {
1958 					FILEDESC_SUNLOCK(fdesc);
1959 					error = EBADF;
1960 					goto out;
1961 				}
1962 				if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
1963 					FILEDESC_SUNLOCK(fdesc);
1964 					error = EOPNOTSUPP;
1965 					goto out;
1966 				}
1967 
1968 			}
1969 
1970 			/*
1971 			 * Now replace the integer FDs with pointers to the
1972 			 * file structure and capability rights.
1973 			 */
1974 			newlen = oldfds * sizeof(fdep[0]);
1975 			*controlp = sbcreatecontrol(NULL, newlen,
1976 			    SCM_RIGHTS, SOL_SOCKET);
1977 			if (*controlp == NULL) {
1978 				FILEDESC_SUNLOCK(fdesc);
1979 				error = E2BIG;
1980 				goto out;
1981 			}
1982 			fdp = data;
1983 			fdep = (struct filedescent **)
1984 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1985 			fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
1986 			    M_WAITOK);
1987 			for (i = 0; i < oldfds; i++, fdev++, fdp++) {
1988 				fde = &fdesc->fd_ofiles[*fdp];
1989 				fdep[i] = fdev;
1990 				fdep[i]->fde_file = fde->fde_file;
1991 				filecaps_copy(&fde->fde_caps,
1992 				    &fdep[i]->fde_caps, true);
1993 				unp_internalize_fp(fdep[i]->fde_file);
1994 			}
1995 			FILEDESC_SUNLOCK(fdesc);
1996 			break;
1997 
1998 		case SCM_TIMESTAMP:
1999 			*controlp = sbcreatecontrol(NULL, sizeof(*tv),
2000 			    SCM_TIMESTAMP, SOL_SOCKET);
2001 			if (*controlp == NULL) {
2002 				error = ENOBUFS;
2003 				goto out;
2004 			}
2005 			tv = (struct timeval *)
2006 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2007 			microtime(tv);
2008 			break;
2009 
2010 		case SCM_BINTIME:
2011 			*controlp = sbcreatecontrol(NULL, sizeof(*bt),
2012 			    SCM_BINTIME, SOL_SOCKET);
2013 			if (*controlp == NULL) {
2014 				error = ENOBUFS;
2015 				goto out;
2016 			}
2017 			bt = (struct bintime *)
2018 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2019 			bintime(bt);
2020 			break;
2021 
2022 		default:
2023 			error = EINVAL;
2024 			goto out;
2025 		}
2026 
2027 		controlp = &(*controlp)->m_next;
2028 		if (CMSG_SPACE(datalen) < clen) {
2029 			clen -= CMSG_SPACE(datalen);
2030 			cm = (struct cmsghdr *)
2031 			    ((caddr_t)cm + CMSG_SPACE(datalen));
2032 		} else {
2033 			clen = 0;
2034 			cm = NULL;
2035 		}
2036 	}
2037 
2038 out:
2039 	m_freem(control);
2040 	return (error);
2041 }
2042 
2043 static struct mbuf *
2044 unp_addsockcred(struct thread *td, struct mbuf *control)
2045 {
2046 	struct mbuf *m, *n, *n_prev;
2047 	struct sockcred *sc;
2048 	const struct cmsghdr *cm;
2049 	int ngroups;
2050 	int i;
2051 
2052 	ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
2053 	m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET);
2054 	if (m == NULL)
2055 		return (control);
2056 
2057 	sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *));
2058 	sc->sc_uid = td->td_ucred->cr_ruid;
2059 	sc->sc_euid = td->td_ucred->cr_uid;
2060 	sc->sc_gid = td->td_ucred->cr_rgid;
2061 	sc->sc_egid = td->td_ucred->cr_gid;
2062 	sc->sc_ngroups = ngroups;
2063 	for (i = 0; i < sc->sc_ngroups; i++)
2064 		sc->sc_groups[i] = td->td_ucred->cr_groups[i];
2065 
2066 	/*
2067 	 * Unlink SCM_CREDS control messages (struct cmsgcred), since just
2068 	 * created SCM_CREDS control message (struct sockcred) has another
2069 	 * format.
2070 	 */
2071 	if (control != NULL)
2072 		for (n = control, n_prev = NULL; n != NULL;) {
2073 			cm = mtod(n, struct cmsghdr *);
2074     			if (cm->cmsg_level == SOL_SOCKET &&
2075 			    cm->cmsg_type == SCM_CREDS) {
2076     				if (n_prev == NULL)
2077 					control = n->m_next;
2078 				else
2079 					n_prev->m_next = n->m_next;
2080 				n = m_free(n);
2081 			} else {
2082 				n_prev = n;
2083 				n = n->m_next;
2084 			}
2085 		}
2086 
2087 	/* Prepend it to the head. */
2088 	m->m_next = control;
2089 	return (m);
2090 }
2091 
2092 static struct unpcb *
2093 fptounp(struct file *fp)
2094 {
2095 	struct socket *so;
2096 
2097 	if (fp->f_type != DTYPE_SOCKET)
2098 		return (NULL);
2099 	if ((so = fp->f_data) == NULL)
2100 		return (NULL);
2101 	if (so->so_proto->pr_domain != &localdomain)
2102 		return (NULL);
2103 	return sotounpcb(so);
2104 }
2105 
2106 static void
2107 unp_discard(struct file *fp)
2108 {
2109 	struct unp_defer *dr;
2110 
2111 	if (unp_externalize_fp(fp)) {
2112 		dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
2113 		dr->ud_fp = fp;
2114 		UNP_DEFERRED_LOCK();
2115 		SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
2116 		UNP_DEFERRED_UNLOCK();
2117 		atomic_add_int(&unp_defers_count, 1);
2118 		taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
2119 	} else
2120 		(void) closef(fp, (struct thread *)NULL);
2121 }
2122 
2123 static void
2124 unp_process_defers(void *arg __unused, int pending)
2125 {
2126 	struct unp_defer *dr;
2127 	SLIST_HEAD(, unp_defer) drl;
2128 	int count;
2129 
2130 	SLIST_INIT(&drl);
2131 	for (;;) {
2132 		UNP_DEFERRED_LOCK();
2133 		if (SLIST_FIRST(&unp_defers) == NULL) {
2134 			UNP_DEFERRED_UNLOCK();
2135 			break;
2136 		}
2137 		SLIST_SWAP(&unp_defers, &drl, unp_defer);
2138 		UNP_DEFERRED_UNLOCK();
2139 		count = 0;
2140 		while ((dr = SLIST_FIRST(&drl)) != NULL) {
2141 			SLIST_REMOVE_HEAD(&drl, ud_link);
2142 			closef(dr->ud_fp, NULL);
2143 			free(dr, M_TEMP);
2144 			count++;
2145 		}
2146 		atomic_add_int(&unp_defers_count, -count);
2147 	}
2148 }
2149 
2150 static void
2151 unp_internalize_fp(struct file *fp)
2152 {
2153 	struct unpcb *unp;
2154 
2155 	UNP_LINK_WLOCK();
2156 	if ((unp = fptounp(fp)) != NULL) {
2157 		unp->unp_file = fp;
2158 		unp->unp_msgcount++;
2159 	}
2160 	fhold(fp);
2161 	unp_rights++;
2162 	UNP_LINK_WUNLOCK();
2163 }
2164 
2165 static int
2166 unp_externalize_fp(struct file *fp)
2167 {
2168 	struct unpcb *unp;
2169 	int ret;
2170 
2171 	UNP_LINK_WLOCK();
2172 	if ((unp = fptounp(fp)) != NULL) {
2173 		unp->unp_msgcount--;
2174 		ret = 1;
2175 	} else
2176 		ret = 0;
2177 	unp_rights--;
2178 	UNP_LINK_WUNLOCK();
2179 	return (ret);
2180 }
2181 
2182 /*
2183  * unp_defer indicates whether additional work has been defered for a future
2184  * pass through unp_gc().  It is thread local and does not require explicit
2185  * synchronization.
2186  */
2187 static int	unp_marked;
2188 static int	unp_unreachable;
2189 
2190 static void
2191 unp_accessable(struct filedescent **fdep, int fdcount)
2192 {
2193 	struct unpcb *unp;
2194 	struct file *fp;
2195 	int i;
2196 
2197 	for (i = 0; i < fdcount; i++) {
2198 		fp = fdep[i]->fde_file;
2199 		if ((unp = fptounp(fp)) == NULL)
2200 			continue;
2201 		if (unp->unp_gcflag & UNPGC_REF)
2202 			continue;
2203 		unp->unp_gcflag &= ~UNPGC_DEAD;
2204 		unp->unp_gcflag |= UNPGC_REF;
2205 		unp_marked++;
2206 	}
2207 }
2208 
2209 static void
2210 unp_gc_process(struct unpcb *unp)
2211 {
2212 	struct socket *soa;
2213 	struct socket *so;
2214 	struct file *fp;
2215 
2216 	/* Already processed. */
2217 	if (unp->unp_gcflag & UNPGC_SCANNED)
2218 		return;
2219 	fp = unp->unp_file;
2220 
2221 	/*
2222 	 * Check for a socket potentially in a cycle.  It must be in a
2223 	 * queue as indicated by msgcount, and this must equal the file
2224 	 * reference count.  Note that when msgcount is 0 the file is NULL.
2225 	 */
2226 	if ((unp->unp_gcflag & UNPGC_REF) == 0 && fp &&
2227 	    unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) {
2228 		unp->unp_gcflag |= UNPGC_DEAD;
2229 		unp_unreachable++;
2230 		return;
2231 	}
2232 
2233 	/*
2234 	 * Mark all sockets we reference with RIGHTS.
2235 	 */
2236 	so = unp->unp_socket;
2237 	if ((unp->unp_gcflag & UNPGC_IGNORE_RIGHTS) == 0) {
2238 		SOCKBUF_LOCK(&so->so_rcv);
2239 		unp_scan(so->so_rcv.sb_mb, unp_accessable);
2240 		SOCKBUF_UNLOCK(&so->so_rcv);
2241 	}
2242 
2243 	/*
2244 	 * Mark all sockets in our accept queue.
2245 	 */
2246 	ACCEPT_LOCK();
2247 	TAILQ_FOREACH(soa, &so->so_comp, so_list) {
2248 		if ((sotounpcb(soa)->unp_gcflag & UNPGC_IGNORE_RIGHTS) != 0)
2249 			continue;
2250 		SOCKBUF_LOCK(&soa->so_rcv);
2251 		unp_scan(soa->so_rcv.sb_mb, unp_accessable);
2252 		SOCKBUF_UNLOCK(&soa->so_rcv);
2253 	}
2254 	ACCEPT_UNLOCK();
2255 	unp->unp_gcflag |= UNPGC_SCANNED;
2256 }
2257 
2258 static int unp_recycled;
2259 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0,
2260     "Number of unreachable sockets claimed by the garbage collector.");
2261 
2262 static int unp_taskcount;
2263 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0,
2264     "Number of times the garbage collector has run.");
2265 
2266 static void
2267 unp_gc(__unused void *arg, int pending)
2268 {
2269 	struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead,
2270 				    NULL };
2271 	struct unp_head **head;
2272 	struct file *f, **unref;
2273 	struct unpcb *unp;
2274 	int i, total;
2275 
2276 	unp_taskcount++;
2277 	UNP_LIST_LOCK();
2278 	/*
2279 	 * First clear all gc flags from previous runs, apart from
2280 	 * UNPGC_IGNORE_RIGHTS.
2281 	 */
2282 	for (head = heads; *head != NULL; head++)
2283 		LIST_FOREACH(unp, *head, unp_link)
2284 			unp->unp_gcflag =
2285 			    (unp->unp_gcflag & UNPGC_IGNORE_RIGHTS);
2286 
2287 	/*
2288 	 * Scan marking all reachable sockets with UNPGC_REF.  Once a socket
2289 	 * is reachable all of the sockets it references are reachable.
2290 	 * Stop the scan once we do a complete loop without discovering
2291 	 * a new reachable socket.
2292 	 */
2293 	do {
2294 		unp_unreachable = 0;
2295 		unp_marked = 0;
2296 		for (head = heads; *head != NULL; head++)
2297 			LIST_FOREACH(unp, *head, unp_link)
2298 				unp_gc_process(unp);
2299 	} while (unp_marked);
2300 	UNP_LIST_UNLOCK();
2301 	if (unp_unreachable == 0)
2302 		return;
2303 
2304 	/*
2305 	 * Allocate space for a local list of dead unpcbs.
2306 	 */
2307 	unref = malloc(unp_unreachable * sizeof(struct file *),
2308 	    M_TEMP, M_WAITOK);
2309 
2310 	/*
2311 	 * Iterate looking for sockets which have been specifically marked
2312 	 * as as unreachable and store them locally.
2313 	 */
2314 	UNP_LINK_RLOCK();
2315 	UNP_LIST_LOCK();
2316 	for (total = 0, head = heads; *head != NULL; head++)
2317 		LIST_FOREACH(unp, *head, unp_link)
2318 			if ((unp->unp_gcflag & UNPGC_DEAD) != 0) {
2319 				f = unp->unp_file;
2320 				if (unp->unp_msgcount == 0 || f == NULL ||
2321 				    f->f_count != unp->unp_msgcount)
2322 					continue;
2323 				unref[total++] = f;
2324 				fhold(f);
2325 				KASSERT(total <= unp_unreachable,
2326 				    ("unp_gc: incorrect unreachable count."));
2327 			}
2328 	UNP_LIST_UNLOCK();
2329 	UNP_LINK_RUNLOCK();
2330 
2331 	/*
2332 	 * Now flush all sockets, free'ing rights.  This will free the
2333 	 * struct files associated with these sockets but leave each socket
2334 	 * with one remaining ref.
2335 	 */
2336 	for (i = 0; i < total; i++) {
2337 		struct socket *so;
2338 
2339 		so = unref[i]->f_data;
2340 		CURVNET_SET(so->so_vnet);
2341 		sorflush(so);
2342 		CURVNET_RESTORE();
2343 	}
2344 
2345 	/*
2346 	 * And finally release the sockets so they can be reclaimed.
2347 	 */
2348 	for (i = 0; i < total; i++)
2349 		fdrop(unref[i], NULL);
2350 	unp_recycled += total;
2351 	free(unref, M_TEMP);
2352 }
2353 
2354 static void
2355 unp_dispose_mbuf(struct mbuf *m)
2356 {
2357 
2358 	if (m)
2359 		unp_scan(m, unp_freerights);
2360 }
2361 
2362 /*
2363  * Synchronize against unp_gc, which can trip over data as we are freeing it.
2364  */
2365 static void
2366 unp_dispose(struct socket *so)
2367 {
2368 	struct unpcb *unp;
2369 
2370 	unp = sotounpcb(so);
2371 	UNP_LIST_LOCK();
2372 	unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
2373 	UNP_LIST_UNLOCK();
2374 	unp_dispose_mbuf(so->so_rcv.sb_mb);
2375 }
2376 
2377 static void
2378 unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
2379 {
2380 	struct mbuf *m;
2381 	struct cmsghdr *cm;
2382 	void *data;
2383 	socklen_t clen, datalen;
2384 
2385 	while (m0 != NULL) {
2386 		for (m = m0; m; m = m->m_next) {
2387 			if (m->m_type != MT_CONTROL)
2388 				continue;
2389 
2390 			cm = mtod(m, struct cmsghdr *);
2391 			clen = m->m_len;
2392 
2393 			while (cm != NULL) {
2394 				if (sizeof(*cm) > clen || cm->cmsg_len > clen)
2395 					break;
2396 
2397 				data = CMSG_DATA(cm);
2398 				datalen = (caddr_t)cm + cm->cmsg_len
2399 				    - (caddr_t)data;
2400 
2401 				if (cm->cmsg_level == SOL_SOCKET &&
2402 				    cm->cmsg_type == SCM_RIGHTS) {
2403 					(*op)(data, datalen /
2404 					    sizeof(struct filedescent *));
2405 				}
2406 
2407 				if (CMSG_SPACE(datalen) < clen) {
2408 					clen -= CMSG_SPACE(datalen);
2409 					cm = (struct cmsghdr *)
2410 					    ((caddr_t)cm + CMSG_SPACE(datalen));
2411 				} else {
2412 					clen = 0;
2413 					cm = NULL;
2414 				}
2415 			}
2416 		}
2417 		m0 = m0->m_nextpkt;
2418 	}
2419 }
2420 
2421 /*
2422  * A helper function called by VFS before socket-type vnode reclamation.
2423  * For an active vnode it clears unp_vnode pointer and decrements unp_vnode
2424  * use count.
2425  */
2426 void
2427 vfs_unp_reclaim(struct vnode *vp)
2428 {
2429 	struct socket *so;
2430 	struct unpcb *unp;
2431 	int active;
2432 
2433 	ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
2434 	KASSERT(vp->v_type == VSOCK,
2435 	    ("vfs_unp_reclaim: vp->v_type != VSOCK"));
2436 
2437 	active = 0;
2438 	UNP_LINK_WLOCK();
2439 	VOP_UNP_CONNECT(vp, &so);
2440 	if (so == NULL)
2441 		goto done;
2442 	unp = sotounpcb(so);
2443 	if (unp == NULL)
2444 		goto done;
2445 	UNP_PCB_LOCK(unp);
2446 	if (unp->unp_vnode == vp) {
2447 		VOP_UNP_DETACH(vp);
2448 		unp->unp_vnode = NULL;
2449 		active = 1;
2450 	}
2451 	UNP_PCB_UNLOCK(unp);
2452 done:
2453 	UNP_LINK_WUNLOCK();
2454 	if (active)
2455 		vunref(vp);
2456 }
2457 
2458 #ifdef DDB
2459 static void
2460 db_print_indent(int indent)
2461 {
2462 	int i;
2463 
2464 	for (i = 0; i < indent; i++)
2465 		db_printf(" ");
2466 }
2467 
2468 static void
2469 db_print_unpflags(int unp_flags)
2470 {
2471 	int comma;
2472 
2473 	comma = 0;
2474 	if (unp_flags & UNP_HAVEPC) {
2475 		db_printf("%sUNP_HAVEPC", comma ? ", " : "");
2476 		comma = 1;
2477 	}
2478 	if (unp_flags & UNP_HAVEPCCACHED) {
2479 		db_printf("%sUNP_HAVEPCCACHED", comma ? ", " : "");
2480 		comma = 1;
2481 	}
2482 	if (unp_flags & UNP_WANTCRED) {
2483 		db_printf("%sUNP_WANTCRED", comma ? ", " : "");
2484 		comma = 1;
2485 	}
2486 	if (unp_flags & UNP_CONNWAIT) {
2487 		db_printf("%sUNP_CONNWAIT", comma ? ", " : "");
2488 		comma = 1;
2489 	}
2490 	if (unp_flags & UNP_CONNECTING) {
2491 		db_printf("%sUNP_CONNECTING", comma ? ", " : "");
2492 		comma = 1;
2493 	}
2494 	if (unp_flags & UNP_BINDING) {
2495 		db_printf("%sUNP_BINDING", comma ? ", " : "");
2496 		comma = 1;
2497 	}
2498 }
2499 
2500 static void
2501 db_print_xucred(int indent, struct xucred *xu)
2502 {
2503 	int comma, i;
2504 
2505 	db_print_indent(indent);
2506 	db_printf("cr_version: %u   cr_uid: %u   cr_ngroups: %d\n",
2507 	    xu->cr_version, xu->cr_uid, xu->cr_ngroups);
2508 	db_print_indent(indent);
2509 	db_printf("cr_groups: ");
2510 	comma = 0;
2511 	for (i = 0; i < xu->cr_ngroups; i++) {
2512 		db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
2513 		comma = 1;
2514 	}
2515 	db_printf("\n");
2516 }
2517 
2518 static void
2519 db_print_unprefs(int indent, struct unp_head *uh)
2520 {
2521 	struct unpcb *unp;
2522 	int counter;
2523 
2524 	counter = 0;
2525 	LIST_FOREACH(unp, uh, unp_reflink) {
2526 		if (counter % 4 == 0)
2527 			db_print_indent(indent);
2528 		db_printf("%p  ", unp);
2529 		if (counter % 4 == 3)
2530 			db_printf("\n");
2531 		counter++;
2532 	}
2533 	if (counter != 0 && counter % 4 != 0)
2534 		db_printf("\n");
2535 }
2536 
2537 DB_SHOW_COMMAND(unpcb, db_show_unpcb)
2538 {
2539 	struct unpcb *unp;
2540 
2541         if (!have_addr) {
2542                 db_printf("usage: show unpcb <addr>\n");
2543                 return;
2544         }
2545         unp = (struct unpcb *)addr;
2546 
2547 	db_printf("unp_socket: %p   unp_vnode: %p\n", unp->unp_socket,
2548 	    unp->unp_vnode);
2549 
2550 	db_printf("unp_ino: %ju   unp_conn: %p\n", (uintmax_t)unp->unp_ino,
2551 	    unp->unp_conn);
2552 
2553 	db_printf("unp_refs:\n");
2554 	db_print_unprefs(2, &unp->unp_refs);
2555 
2556 	/* XXXRW: Would be nice to print the full address, if any. */
2557 	db_printf("unp_addr: %p\n", unp->unp_addr);
2558 
2559 	db_printf("unp_gencnt: %llu\n",
2560 	    (unsigned long long)unp->unp_gencnt);
2561 
2562 	db_printf("unp_flags: %x (", unp->unp_flags);
2563 	db_print_unpflags(unp->unp_flags);
2564 	db_printf(")\n");
2565 
2566 	db_printf("unp_peercred:\n");
2567 	db_print_xucred(2, &unp->unp_peercred);
2568 
2569 	db_printf("unp_refcount: %u\n", unp->unp_refcount);
2570 }
2571 #endif
2572