xref: /freebsd/sys/kern/uipc_usrreq.c (revision f2b7bf8afcfd630e0fbd8417f1ce974de79feaf0)
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);
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 	if ((vp = unp->unp_vnode) != NULL) {
674 		VOP_UNP_DETACH(vp);
675 		unp->unp_vnode = NULL;
676 	}
677 	unp2 = unp->unp_conn;
678 	if (unp2 != NULL) {
679 		UNP_PCB_LOCK(unp2);
680 		unp_disconnect(unp, unp2);
681 		UNP_PCB_UNLOCK(unp2);
682 	}
683 
684 	/*
685 	 * We hold the linkage lock exclusively, so it's OK to acquire
686 	 * multiple pcb locks at a time.
687 	 */
688 	while (!LIST_EMPTY(&unp->unp_refs)) {
689 		struct unpcb *ref = LIST_FIRST(&unp->unp_refs);
690 
691 		UNP_PCB_LOCK(ref);
692 		unp_drop(ref);
693 		UNP_PCB_UNLOCK(ref);
694 	}
695 	local_unp_rights = unp_rights;
696 	UNP_LINK_WUNLOCK();
697 teardown:
698 	unp->unp_socket->so_pcb = NULL;
699 	saved_unp_addr = unp->unp_addr;
700 	unp->unp_addr = NULL;
701 	unp->unp_refcount--;
702 	freeunp = (unp->unp_refcount == 0);
703 	if (saved_unp_addr != NULL)
704 		free(saved_unp_addr, M_SONAME);
705 	if (freeunp) {
706 		UNP_PCB_LOCK_DESTROY(unp);
707 		uma_zfree(unp_zone, unp);
708 	} else
709 		UNP_PCB_UNLOCK(unp);
710 	if (vp)
711 		vrele(vp);
712 	if (local_unp_rights)
713 		taskqueue_enqueue_timeout(taskqueue_thread, &unp_gc_task, -1);
714 }
715 
716 static int
717 uipc_disconnect(struct socket *so)
718 {
719 	struct unpcb *unp, *unp2;
720 
721 	unp = sotounpcb(so);
722 	KASSERT(unp != NULL, ("uipc_disconnect: unp == NULL"));
723 
724 	UNP_LINK_WLOCK();
725 	UNP_PCB_LOCK(unp);
726 	unp2 = unp->unp_conn;
727 	if (unp2 != NULL) {
728 		UNP_PCB_LOCK(unp2);
729 		unp_disconnect(unp, unp2);
730 		UNP_PCB_UNLOCK(unp2);
731 	}
732 	UNP_PCB_UNLOCK(unp);
733 	UNP_LINK_WUNLOCK();
734 	return (0);
735 }
736 
737 static int
738 uipc_listen(struct socket *so, int backlog, struct thread *td)
739 {
740 	struct unpcb *unp;
741 	int error;
742 
743 	if (so->so_type != SOCK_STREAM && so->so_type != SOCK_SEQPACKET)
744 		return (EOPNOTSUPP);
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 		solisten_proto(so, backlog);
762 	}
763 	SOCK_UNLOCK(so);
764 	UNP_PCB_UNLOCK(unp);
765 	return (error);
766 }
767 
768 static int
769 uipc_peeraddr(struct socket *so, struct sockaddr **nam)
770 {
771 	struct unpcb *unp, *unp2;
772 	const struct sockaddr *sa;
773 
774 	unp = sotounpcb(so);
775 	KASSERT(unp != NULL, ("uipc_peeraddr: unp == NULL"));
776 
777 	*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
778 	UNP_LINK_RLOCK();
779 	/*
780 	 * XXX: It seems that this test always fails even when connection is
781 	 * established.  So, this else clause is added as workaround to
782 	 * return PF_LOCAL sockaddr.
783 	 */
784 	unp2 = unp->unp_conn;
785 	if (unp2 != NULL) {
786 		UNP_PCB_LOCK(unp2);
787 		if (unp2->unp_addr != NULL)
788 			sa = (struct sockaddr *) unp2->unp_addr;
789 		else
790 			sa = &sun_noname;
791 		bcopy(sa, *nam, sa->sa_len);
792 		UNP_PCB_UNLOCK(unp2);
793 	} else {
794 		sa = &sun_noname;
795 		bcopy(sa, *nam, sa->sa_len);
796 	}
797 	UNP_LINK_RUNLOCK();
798 	return (0);
799 }
800 
801 static int
802 uipc_rcvd(struct socket *so, int flags)
803 {
804 	struct unpcb *unp, *unp2;
805 	struct socket *so2;
806 	u_int mbcnt, sbcc;
807 
808 	unp = sotounpcb(so);
809 	KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
810 	KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_SEQPACKET,
811 	    ("%s: socktype %d", __func__, so->so_type));
812 
813 	/*
814 	 * Adjust backpressure on sender and wakeup any waiting to write.
815 	 *
816 	 * The unp lock is acquired to maintain the validity of the unp_conn
817 	 * pointer; no lock on unp2 is required as unp2->unp_socket will be
818 	 * static as long as we don't permit unp2 to disconnect from unp,
819 	 * which is prevented by the lock on unp.  We cache values from
820 	 * so_rcv to avoid holding the so_rcv lock over the entire
821 	 * transaction on the remote so_snd.
822 	 */
823 	SOCKBUF_LOCK(&so->so_rcv);
824 	mbcnt = so->so_rcv.sb_mbcnt;
825 	sbcc = sbavail(&so->so_rcv);
826 	SOCKBUF_UNLOCK(&so->so_rcv);
827 	/*
828 	 * There is a benign race condition at this point.  If we're planning to
829 	 * clear SB_STOP, but uipc_send is called on the connected socket at
830 	 * this instant, it might add data to the sockbuf and set SB_STOP.  Then
831 	 * we would erroneously clear SB_STOP below, even though the sockbuf is
832 	 * full.  The race is benign because the only ill effect is to allow the
833 	 * sockbuf to exceed its size limit, and the size limits are not
834 	 * strictly guaranteed anyway.
835 	 */
836 	UNP_PCB_LOCK(unp);
837 	unp2 = unp->unp_conn;
838 	if (unp2 == NULL) {
839 		UNP_PCB_UNLOCK(unp);
840 		return (0);
841 	}
842 	so2 = unp2->unp_socket;
843 	SOCKBUF_LOCK(&so2->so_snd);
844 	if (sbcc < so2->so_snd.sb_hiwat && mbcnt < so2->so_snd.sb_mbmax)
845 		so2->so_snd.sb_flags &= ~SB_STOP;
846 	sowwakeup_locked(so2);
847 	UNP_PCB_UNLOCK(unp);
848 	return (0);
849 }
850 
851 static int
852 uipc_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *nam,
853     struct mbuf *control, struct thread *td)
854 {
855 	struct unpcb *unp, *unp2;
856 	struct socket *so2;
857 	u_int mbcnt, sbcc;
858 	int error = 0;
859 
860 	unp = sotounpcb(so);
861 	KASSERT(unp != NULL, ("%s: unp == NULL", __func__));
862 	KASSERT(so->so_type == SOCK_STREAM || so->so_type == SOCK_DGRAM ||
863 	    so->so_type == SOCK_SEQPACKET,
864 	    ("%s: socktype %d", __func__, so->so_type));
865 
866 	if (flags & PRUS_OOB) {
867 		error = EOPNOTSUPP;
868 		goto release;
869 	}
870 	if (control != NULL && (error = unp_internalize(&control, td)))
871 		goto release;
872 	if ((nam != NULL) || (flags & PRUS_EOF))
873 		UNP_LINK_WLOCK();
874 	else
875 		UNP_LINK_RLOCK();
876 	switch (so->so_type) {
877 	case SOCK_DGRAM:
878 	{
879 		const struct sockaddr *from;
880 
881 		unp2 = unp->unp_conn;
882 		if (nam != NULL) {
883 			UNP_LINK_WLOCK_ASSERT();
884 			if (unp2 != NULL) {
885 				error = EISCONN;
886 				break;
887 			}
888 			error = unp_connect(so, nam, td);
889 			if (error)
890 				break;
891 			unp2 = unp->unp_conn;
892 		}
893 
894 		/*
895 		 * Because connect() and send() are non-atomic in a sendto()
896 		 * with a target address, it's possible that the socket will
897 		 * have disconnected before the send() can run.  In that case
898 		 * return the slightly counter-intuitive but otherwise
899 		 * correct error that the socket is not connected.
900 		 */
901 		if (unp2 == NULL) {
902 			error = ENOTCONN;
903 			break;
904 		}
905 		/* Lockless read. */
906 		if (unp2->unp_flags & UNP_WANTCRED)
907 			control = unp_addsockcred(td, control);
908 		UNP_PCB_LOCK(unp);
909 		if (unp->unp_addr != NULL)
910 			from = (struct sockaddr *)unp->unp_addr;
911 		else
912 			from = &sun_noname;
913 		so2 = unp2->unp_socket;
914 		SOCKBUF_LOCK(&so2->so_rcv);
915 		if (sbappendaddr_locked(&so2->so_rcv, from, m,
916 		    control)) {
917 			sorwakeup_locked(so2);
918 			m = NULL;
919 			control = NULL;
920 		} else {
921 			SOCKBUF_UNLOCK(&so2->so_rcv);
922 			error = ENOBUFS;
923 		}
924 		if (nam != NULL) {
925 			UNP_LINK_WLOCK_ASSERT();
926 			UNP_PCB_LOCK(unp2);
927 			unp_disconnect(unp, unp2);
928 			UNP_PCB_UNLOCK(unp2);
929 		}
930 		UNP_PCB_UNLOCK(unp);
931 		break;
932 	}
933 
934 	case SOCK_SEQPACKET:
935 	case SOCK_STREAM:
936 		if ((so->so_state & SS_ISCONNECTED) == 0) {
937 			if (nam != NULL) {
938 				UNP_LINK_WLOCK_ASSERT();
939 				error = unp_connect(so, nam, td);
940 				if (error)
941 					break;	/* XXX */
942 			} else {
943 				error = ENOTCONN;
944 				break;
945 			}
946 		}
947 
948 		/* Lockless read. */
949 		if (so->so_snd.sb_state & SBS_CANTSENDMORE) {
950 			error = EPIPE;
951 			break;
952 		}
953 
954 		/*
955 		 * Because connect() and send() are non-atomic in a sendto()
956 		 * with a target address, it's possible that the socket will
957 		 * have disconnected before the send() can run.  In that case
958 		 * return the slightly counter-intuitive but otherwise
959 		 * correct error that the socket is not connected.
960 		 *
961 		 * Locking here must be done carefully: the linkage lock
962 		 * prevents interconnections between unpcbs from changing, so
963 		 * we can traverse from unp to unp2 without acquiring unp's
964 		 * lock.  Socket buffer locks follow unpcb locks, so we can
965 		 * acquire both remote and lock socket buffer locks.
966 		 */
967 		unp2 = unp->unp_conn;
968 		if (unp2 == NULL) {
969 			error = ENOTCONN;
970 			break;
971 		}
972 		so2 = unp2->unp_socket;
973 		UNP_PCB_LOCK(unp2);
974 		SOCKBUF_LOCK(&so2->so_rcv);
975 		if (unp2->unp_flags & UNP_WANTCRED) {
976 			/*
977 			 * Credentials are passed only once on SOCK_STREAM
978 			 * and SOCK_SEQPACKET.
979 			 */
980 			unp2->unp_flags &= ~UNP_WANTCRED;
981 			control = unp_addsockcred(td, control);
982 		}
983 		/*
984 		 * Send to paired receive port, and then reduce send buffer
985 		 * hiwater marks to maintain backpressure.  Wake up readers.
986 		 */
987 		switch (so->so_type) {
988 		case SOCK_STREAM:
989 			if (control != NULL) {
990 				if (sbappendcontrol_locked(&so2->so_rcv, m,
991 				    control))
992 					control = NULL;
993 			} else
994 				sbappend_locked(&so2->so_rcv, m, flags);
995 			break;
996 
997 		case SOCK_SEQPACKET: {
998 			const struct sockaddr *from;
999 
1000 			from = &sun_noname;
1001 			/*
1002 			 * Don't check for space available in so2->so_rcv.
1003 			 * Unix domain sockets only check for space in the
1004 			 * sending sockbuf, and that check is performed one
1005 			 * level up the stack.
1006 			 */
1007 			if (sbappendaddr_nospacecheck_locked(&so2->so_rcv,
1008 				from, m, control))
1009 				control = NULL;
1010 			break;
1011 			}
1012 		}
1013 
1014 		mbcnt = so2->so_rcv.sb_mbcnt;
1015 		sbcc = sbavail(&so2->so_rcv);
1016 		if (sbcc)
1017 			sorwakeup_locked(so2);
1018 		else
1019 			SOCKBUF_UNLOCK(&so2->so_rcv);
1020 
1021 		/*
1022 		 * The PCB lock on unp2 protects the SB_STOP flag.  Without it,
1023 		 * it would be possible for uipc_rcvd to be called at this
1024 		 * point, drain the receiving sockbuf, clear SB_STOP, and then
1025 		 * we would set SB_STOP below.  That could lead to an empty
1026 		 * sockbuf having SB_STOP set
1027 		 */
1028 		SOCKBUF_LOCK(&so->so_snd);
1029 		if (sbcc >= so->so_snd.sb_hiwat || mbcnt >= so->so_snd.sb_mbmax)
1030 			so->so_snd.sb_flags |= SB_STOP;
1031 		SOCKBUF_UNLOCK(&so->so_snd);
1032 		UNP_PCB_UNLOCK(unp2);
1033 		m = NULL;
1034 		break;
1035 	}
1036 
1037 	/*
1038 	 * PRUS_EOF is equivalent to pru_send followed by pru_shutdown.
1039 	 */
1040 	if (flags & PRUS_EOF) {
1041 		UNP_PCB_LOCK(unp);
1042 		socantsendmore(so);
1043 		unp_shutdown(unp);
1044 		UNP_PCB_UNLOCK(unp);
1045 	}
1046 
1047 	if ((nam != NULL) || (flags & PRUS_EOF))
1048 		UNP_LINK_WUNLOCK();
1049 	else
1050 		UNP_LINK_RUNLOCK();
1051 
1052 	if (control != NULL && error != 0)
1053 		unp_dispose_mbuf(control);
1054 
1055 release:
1056 	if (control != NULL)
1057 		m_freem(control);
1058 	if (m != NULL)
1059 		m_freem(m);
1060 	return (error);
1061 }
1062 
1063 static int
1064 uipc_ready(struct socket *so, struct mbuf *m, int count)
1065 {
1066 	struct unpcb *unp, *unp2;
1067 	struct socket *so2;
1068 	int error;
1069 
1070 	unp = sotounpcb(so);
1071 
1072 	UNP_LINK_RLOCK();
1073 	unp2 = unp->unp_conn;
1074 	UNP_PCB_LOCK(unp2);
1075 	so2 = unp2->unp_socket;
1076 
1077 	SOCKBUF_LOCK(&so2->so_rcv);
1078 	if ((error = sbready(&so2->so_rcv, m, count)) == 0)
1079 		sorwakeup_locked(so2);
1080 	else
1081 		SOCKBUF_UNLOCK(&so2->so_rcv);
1082 
1083 	UNP_PCB_UNLOCK(unp2);
1084 	UNP_LINK_RUNLOCK();
1085 
1086 	return (error);
1087 }
1088 
1089 static int
1090 uipc_sense(struct socket *so, struct stat *sb)
1091 {
1092 	struct unpcb *unp;
1093 
1094 	unp = sotounpcb(so);
1095 	KASSERT(unp != NULL, ("uipc_sense: unp == NULL"));
1096 
1097 	sb->st_blksize = so->so_snd.sb_hiwat;
1098 	UNP_PCB_LOCK(unp);
1099 	sb->st_dev = NODEV;
1100 	if (unp->unp_ino == 0)
1101 		unp->unp_ino = (++unp_ino == 0) ? ++unp_ino : unp_ino;
1102 	sb->st_ino = unp->unp_ino;
1103 	UNP_PCB_UNLOCK(unp);
1104 	return (0);
1105 }
1106 
1107 static int
1108 uipc_shutdown(struct socket *so)
1109 {
1110 	struct unpcb *unp;
1111 
1112 	unp = sotounpcb(so);
1113 	KASSERT(unp != NULL, ("uipc_shutdown: unp == NULL"));
1114 
1115 	UNP_LINK_WLOCK();
1116 	UNP_PCB_LOCK(unp);
1117 	socantsendmore(so);
1118 	unp_shutdown(unp);
1119 	UNP_PCB_UNLOCK(unp);
1120 	UNP_LINK_WUNLOCK();
1121 	return (0);
1122 }
1123 
1124 static int
1125 uipc_sockaddr(struct socket *so, struct sockaddr **nam)
1126 {
1127 	struct unpcb *unp;
1128 	const struct sockaddr *sa;
1129 
1130 	unp = sotounpcb(so);
1131 	KASSERT(unp != NULL, ("uipc_sockaddr: unp == NULL"));
1132 
1133 	*nam = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1134 	UNP_PCB_LOCK(unp);
1135 	if (unp->unp_addr != NULL)
1136 		sa = (struct sockaddr *) unp->unp_addr;
1137 	else
1138 		sa = &sun_noname;
1139 	bcopy(sa, *nam, sa->sa_len);
1140 	UNP_PCB_UNLOCK(unp);
1141 	return (0);
1142 }
1143 
1144 static struct pr_usrreqs uipc_usrreqs_dgram = {
1145 	.pru_abort = 		uipc_abort,
1146 	.pru_accept =		uipc_accept,
1147 	.pru_attach =		uipc_attach,
1148 	.pru_bind =		uipc_bind,
1149 	.pru_bindat =		uipc_bindat,
1150 	.pru_connect =		uipc_connect,
1151 	.pru_connectat =	uipc_connectat,
1152 	.pru_connect2 =		uipc_connect2,
1153 	.pru_detach =		uipc_detach,
1154 	.pru_disconnect =	uipc_disconnect,
1155 	.pru_listen =		uipc_listen,
1156 	.pru_peeraddr =		uipc_peeraddr,
1157 	.pru_rcvd =		uipc_rcvd,
1158 	.pru_send =		uipc_send,
1159 	.pru_sense =		uipc_sense,
1160 	.pru_shutdown =		uipc_shutdown,
1161 	.pru_sockaddr =		uipc_sockaddr,
1162 	.pru_soreceive =	soreceive_dgram,
1163 	.pru_close =		uipc_close,
1164 };
1165 
1166 static struct pr_usrreqs uipc_usrreqs_seqpacket = {
1167 	.pru_abort =		uipc_abort,
1168 	.pru_accept =		uipc_accept,
1169 	.pru_attach =		uipc_attach,
1170 	.pru_bind =		uipc_bind,
1171 	.pru_bindat =		uipc_bindat,
1172 	.pru_connect =		uipc_connect,
1173 	.pru_connectat =	uipc_connectat,
1174 	.pru_connect2 =		uipc_connect2,
1175 	.pru_detach =		uipc_detach,
1176 	.pru_disconnect =	uipc_disconnect,
1177 	.pru_listen =		uipc_listen,
1178 	.pru_peeraddr =		uipc_peeraddr,
1179 	.pru_rcvd =		uipc_rcvd,
1180 	.pru_send =		uipc_send,
1181 	.pru_sense =		uipc_sense,
1182 	.pru_shutdown =		uipc_shutdown,
1183 	.pru_sockaddr =		uipc_sockaddr,
1184 	.pru_soreceive =	soreceive_generic,	/* XXX: or...? */
1185 	.pru_close =		uipc_close,
1186 };
1187 
1188 static struct pr_usrreqs uipc_usrreqs_stream = {
1189 	.pru_abort = 		uipc_abort,
1190 	.pru_accept =		uipc_accept,
1191 	.pru_attach =		uipc_attach,
1192 	.pru_bind =		uipc_bind,
1193 	.pru_bindat =		uipc_bindat,
1194 	.pru_connect =		uipc_connect,
1195 	.pru_connectat =	uipc_connectat,
1196 	.pru_connect2 =		uipc_connect2,
1197 	.pru_detach =		uipc_detach,
1198 	.pru_disconnect =	uipc_disconnect,
1199 	.pru_listen =		uipc_listen,
1200 	.pru_peeraddr =		uipc_peeraddr,
1201 	.pru_rcvd =		uipc_rcvd,
1202 	.pru_send =		uipc_send,
1203 	.pru_ready =		uipc_ready,
1204 	.pru_sense =		uipc_sense,
1205 	.pru_shutdown =		uipc_shutdown,
1206 	.pru_sockaddr =		uipc_sockaddr,
1207 	.pru_soreceive =	soreceive_generic,
1208 	.pru_close =		uipc_close,
1209 };
1210 
1211 static int
1212 uipc_ctloutput(struct socket *so, struct sockopt *sopt)
1213 {
1214 	struct unpcb *unp;
1215 	struct xucred xu;
1216 	int error, optval;
1217 
1218 	if (sopt->sopt_level != 0)
1219 		return (EINVAL);
1220 
1221 	unp = sotounpcb(so);
1222 	KASSERT(unp != NULL, ("uipc_ctloutput: unp == NULL"));
1223 	error = 0;
1224 	switch (sopt->sopt_dir) {
1225 	case SOPT_GET:
1226 		switch (sopt->sopt_name) {
1227 		case LOCAL_PEERCRED:
1228 			UNP_PCB_LOCK(unp);
1229 			if (unp->unp_flags & UNP_HAVEPC)
1230 				xu = unp->unp_peercred;
1231 			else {
1232 				if (so->so_type == SOCK_STREAM)
1233 					error = ENOTCONN;
1234 				else
1235 					error = EINVAL;
1236 			}
1237 			UNP_PCB_UNLOCK(unp);
1238 			if (error == 0)
1239 				error = sooptcopyout(sopt, &xu, sizeof(xu));
1240 			break;
1241 
1242 		case LOCAL_CREDS:
1243 			/* Unlocked read. */
1244 			optval = unp->unp_flags & UNP_WANTCRED ? 1 : 0;
1245 			error = sooptcopyout(sopt, &optval, sizeof(optval));
1246 			break;
1247 
1248 		case LOCAL_CONNWAIT:
1249 			/* Unlocked read. */
1250 			optval = unp->unp_flags & UNP_CONNWAIT ? 1 : 0;
1251 			error = sooptcopyout(sopt, &optval, sizeof(optval));
1252 			break;
1253 
1254 		default:
1255 			error = EOPNOTSUPP;
1256 			break;
1257 		}
1258 		break;
1259 
1260 	case SOPT_SET:
1261 		switch (sopt->sopt_name) {
1262 		case LOCAL_CREDS:
1263 		case LOCAL_CONNWAIT:
1264 			error = sooptcopyin(sopt, &optval, sizeof(optval),
1265 					    sizeof(optval));
1266 			if (error)
1267 				break;
1268 
1269 #define	OPTSET(bit) do {						\
1270 	UNP_PCB_LOCK(unp);						\
1271 	if (optval)							\
1272 		unp->unp_flags |= bit;					\
1273 	else								\
1274 		unp->unp_flags &= ~bit;					\
1275 	UNP_PCB_UNLOCK(unp);						\
1276 } while (0)
1277 
1278 			switch (sopt->sopt_name) {
1279 			case LOCAL_CREDS:
1280 				OPTSET(UNP_WANTCRED);
1281 				break;
1282 
1283 			case LOCAL_CONNWAIT:
1284 				OPTSET(UNP_CONNWAIT);
1285 				break;
1286 
1287 			default:
1288 				break;
1289 			}
1290 			break;
1291 #undef	OPTSET
1292 		default:
1293 			error = ENOPROTOOPT;
1294 			break;
1295 		}
1296 		break;
1297 
1298 	default:
1299 		error = EOPNOTSUPP;
1300 		break;
1301 	}
1302 	return (error);
1303 }
1304 
1305 static int
1306 unp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
1307 {
1308 
1309 	return (unp_connectat(AT_FDCWD, so, nam, td));
1310 }
1311 
1312 static int
1313 unp_connectat(int fd, struct socket *so, struct sockaddr *nam,
1314     struct thread *td)
1315 {
1316 	struct sockaddr_un *soun = (struct sockaddr_un *)nam;
1317 	struct vnode *vp;
1318 	struct socket *so2, *so3;
1319 	struct unpcb *unp, *unp2, *unp3;
1320 	struct nameidata nd;
1321 	char buf[SOCK_MAXADDRLEN];
1322 	struct sockaddr *sa;
1323 	cap_rights_t rights;
1324 	int error, len;
1325 
1326 	if (nam->sa_family != AF_UNIX)
1327 		return (EAFNOSUPPORT);
1328 
1329 	UNP_LINK_WLOCK_ASSERT();
1330 
1331 	unp = sotounpcb(so);
1332 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1333 
1334 	if (nam->sa_len > sizeof(struct sockaddr_un))
1335 		return (EINVAL);
1336 	len = nam->sa_len - offsetof(struct sockaddr_un, sun_path);
1337 	if (len <= 0)
1338 		return (EINVAL);
1339 	bcopy(soun->sun_path, buf, len);
1340 	buf[len] = 0;
1341 
1342 	UNP_PCB_LOCK(unp);
1343 	if (unp->unp_flags & UNP_CONNECTING) {
1344 		UNP_PCB_UNLOCK(unp);
1345 		return (EALREADY);
1346 	}
1347 	UNP_LINK_WUNLOCK();
1348 	unp->unp_flags |= UNP_CONNECTING;
1349 	UNP_PCB_UNLOCK(unp);
1350 
1351 	sa = malloc(sizeof(struct sockaddr_un), M_SONAME, M_WAITOK);
1352 	NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF,
1353 	    UIO_SYSSPACE, buf, fd, cap_rights_init(&rights, CAP_CONNECTAT), td);
1354 	error = namei(&nd);
1355 	if (error)
1356 		vp = NULL;
1357 	else
1358 		vp = nd.ni_vp;
1359 	ASSERT_VOP_LOCKED(vp, "unp_connect");
1360 	NDFREE(&nd, NDF_ONLY_PNBUF);
1361 	if (error)
1362 		goto bad;
1363 
1364 	if (vp->v_type != VSOCK) {
1365 		error = ENOTSOCK;
1366 		goto bad;
1367 	}
1368 #ifdef MAC
1369 	error = mac_vnode_check_open(td->td_ucred, vp, VWRITE | VREAD);
1370 	if (error)
1371 		goto bad;
1372 #endif
1373 	error = VOP_ACCESS(vp, VWRITE, td->td_ucred, td);
1374 	if (error)
1375 		goto bad;
1376 
1377 	unp = sotounpcb(so);
1378 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1379 
1380 	/*
1381 	 * Lock linkage lock for two reasons: make sure v_socket is stable,
1382 	 * and to protect simultaneous locking of multiple pcbs.
1383 	 */
1384 	UNP_LINK_WLOCK();
1385 	VOP_UNP_CONNECT(vp, &unp2);
1386 	if (unp2 == NULL) {
1387 		error = ECONNREFUSED;
1388 		goto bad2;
1389 	}
1390 	so2 = unp2->unp_socket;
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 		memcpy(&unp->unp_peercred, &unp2->unp_peercred,
1432 		    sizeof(unp->unp_peercred));
1433 		unp->unp_flags |= UNP_HAVEPC;
1434 		if (unp2->unp_flags & UNP_WANTCRED)
1435 			unp3->unp_flags |= UNP_WANTCRED;
1436 		UNP_PCB_UNLOCK(unp3);
1437 		UNP_PCB_UNLOCK(unp2);
1438 		UNP_PCB_UNLOCK(unp);
1439 #ifdef MAC
1440 		mac_socketpeer_set_from_socket(so, so3);
1441 		mac_socketpeer_set_from_socket(so3, so);
1442 #endif
1443 
1444 		so2 = so3;
1445 	}
1446 	unp = sotounpcb(so);
1447 	KASSERT(unp != NULL, ("unp_connect: unp == NULL"));
1448 	unp2 = sotounpcb(so2);
1449 	KASSERT(unp2 != NULL, ("unp_connect: unp2 == NULL"));
1450 	UNP_PCB_LOCK(unp);
1451 	UNP_PCB_LOCK(unp2);
1452 	error = unp_connect2(so, so2, PRU_CONNECT);
1453 	UNP_PCB_UNLOCK(unp2);
1454 	UNP_PCB_UNLOCK(unp);
1455 bad2:
1456 	UNP_LINK_WUNLOCK();
1457 bad:
1458 	if (vp != NULL)
1459 		vput(vp);
1460 	free(sa, M_SONAME);
1461 	UNP_LINK_WLOCK();
1462 	UNP_PCB_LOCK(unp);
1463 	unp->unp_flags &= ~UNP_CONNECTING;
1464 	UNP_PCB_UNLOCK(unp);
1465 	return (error);
1466 }
1467 
1468 static int
1469 unp_connect2(struct socket *so, struct socket *so2, int req)
1470 {
1471 	struct unpcb *unp;
1472 	struct unpcb *unp2;
1473 
1474 	unp = sotounpcb(so);
1475 	KASSERT(unp != NULL, ("unp_connect2: unp == NULL"));
1476 	unp2 = sotounpcb(so2);
1477 	KASSERT(unp2 != NULL, ("unp_connect2: unp2 == NULL"));
1478 
1479 	UNP_LINK_WLOCK_ASSERT();
1480 	UNP_PCB_LOCK_ASSERT(unp);
1481 	UNP_PCB_LOCK_ASSERT(unp2);
1482 
1483 	if (so2->so_type != so->so_type)
1484 		return (EPROTOTYPE);
1485 	unp2->unp_flags &= ~UNP_NASCENT;
1486 	unp->unp_conn = unp2;
1487 
1488 	switch (so->so_type) {
1489 	case SOCK_DGRAM:
1490 		LIST_INSERT_HEAD(&unp2->unp_refs, unp, unp_reflink);
1491 		soisconnected(so);
1492 		break;
1493 
1494 	case SOCK_STREAM:
1495 	case SOCK_SEQPACKET:
1496 		unp2->unp_conn = unp;
1497 		if (req == PRU_CONNECT &&
1498 		    ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
1499 			soisconnecting(so);
1500 		else
1501 			soisconnected(so);
1502 		soisconnected(so2);
1503 		break;
1504 
1505 	default:
1506 		panic("unp_connect2");
1507 	}
1508 	return (0);
1509 }
1510 
1511 static void
1512 unp_disconnect(struct unpcb *unp, struct unpcb *unp2)
1513 {
1514 	struct socket *so;
1515 
1516 	KASSERT(unp2 != NULL, ("unp_disconnect: unp2 == NULL"));
1517 
1518 	UNP_LINK_WLOCK_ASSERT();
1519 	UNP_PCB_LOCK_ASSERT(unp);
1520 	UNP_PCB_LOCK_ASSERT(unp2);
1521 
1522 	unp->unp_conn = NULL;
1523 	switch (unp->unp_socket->so_type) {
1524 	case SOCK_DGRAM:
1525 		LIST_REMOVE(unp, unp_reflink);
1526 		so = unp->unp_socket;
1527 		SOCK_LOCK(so);
1528 		so->so_state &= ~SS_ISCONNECTED;
1529 		SOCK_UNLOCK(so);
1530 		break;
1531 
1532 	case SOCK_STREAM:
1533 	case SOCK_SEQPACKET:
1534 		soisdisconnected(unp->unp_socket);
1535 		unp2->unp_conn = NULL;
1536 		soisdisconnected(unp2->unp_socket);
1537 		break;
1538 	}
1539 }
1540 
1541 /*
1542  * unp_pcblist() walks the global list of struct unpcb's to generate a
1543  * pointer list, bumping the refcount on each unpcb.  It then copies them out
1544  * sequentially, validating the generation number on each to see if it has
1545  * been detached.  All of this is necessary because copyout() may sleep on
1546  * disk I/O.
1547  */
1548 static int
1549 unp_pcblist(SYSCTL_HANDLER_ARGS)
1550 {
1551 	int error, i, n;
1552 	int freeunp;
1553 	struct unpcb *unp, **unp_list;
1554 	unp_gen_t gencnt;
1555 	struct xunpgen *xug;
1556 	struct unp_head *head;
1557 	struct xunpcb *xu;
1558 
1559 	switch ((intptr_t)arg1) {
1560 	case SOCK_STREAM:
1561 		head = &unp_shead;
1562 		break;
1563 
1564 	case SOCK_DGRAM:
1565 		head = &unp_dhead;
1566 		break;
1567 
1568 	case SOCK_SEQPACKET:
1569 		head = &unp_sphead;
1570 		break;
1571 
1572 	default:
1573 		panic("unp_pcblist: arg1 %d", (int)(intptr_t)arg1);
1574 	}
1575 
1576 	/*
1577 	 * The process of preparing the PCB list is too time-consuming and
1578 	 * resource-intensive to repeat twice on every request.
1579 	 */
1580 	if (req->oldptr == NULL) {
1581 		n = unp_count;
1582 		req->oldidx = 2 * (sizeof *xug)
1583 			+ (n + n/8) * sizeof(struct xunpcb);
1584 		return (0);
1585 	}
1586 
1587 	if (req->newptr != NULL)
1588 		return (EPERM);
1589 
1590 	/*
1591 	 * OK, now we're committed to doing something.
1592 	 */
1593 	xug = malloc(sizeof(*xug), M_TEMP, M_WAITOK);
1594 	UNP_LIST_LOCK();
1595 	gencnt = unp_gencnt;
1596 	n = unp_count;
1597 	UNP_LIST_UNLOCK();
1598 
1599 	xug->xug_len = sizeof *xug;
1600 	xug->xug_count = n;
1601 	xug->xug_gen = gencnt;
1602 	xug->xug_sogen = so_gencnt;
1603 	error = SYSCTL_OUT(req, xug, sizeof *xug);
1604 	if (error) {
1605 		free(xug, M_TEMP);
1606 		return (error);
1607 	}
1608 
1609 	unp_list = malloc(n * sizeof *unp_list, M_TEMP, M_WAITOK);
1610 
1611 	UNP_LIST_LOCK();
1612 	for (unp = LIST_FIRST(head), i = 0; unp && i < n;
1613 	     unp = LIST_NEXT(unp, unp_link)) {
1614 		UNP_PCB_LOCK(unp);
1615 		if (unp->unp_gencnt <= gencnt) {
1616 			if (cr_cansee(req->td->td_ucred,
1617 			    unp->unp_socket->so_cred)) {
1618 				UNP_PCB_UNLOCK(unp);
1619 				continue;
1620 			}
1621 			unp_list[i++] = unp;
1622 			unp->unp_refcount++;
1623 		}
1624 		UNP_PCB_UNLOCK(unp);
1625 	}
1626 	UNP_LIST_UNLOCK();
1627 	n = i;			/* In case we lost some during malloc. */
1628 
1629 	error = 0;
1630 	xu = malloc(sizeof(*xu), M_TEMP, M_WAITOK | M_ZERO);
1631 	for (i = 0; i < n; i++) {
1632 		unp = unp_list[i];
1633 		UNP_PCB_LOCK(unp);
1634 		unp->unp_refcount--;
1635 	        if (unp->unp_refcount != 0 && unp->unp_gencnt <= gencnt) {
1636 			xu->xu_len = sizeof *xu;
1637 			xu->xu_unpp = unp;
1638 			/*
1639 			 * XXX - need more locking here to protect against
1640 			 * connect/disconnect races for SMP.
1641 			 */
1642 			if (unp->unp_addr != NULL)
1643 				bcopy(unp->unp_addr, &xu->xu_addr,
1644 				      unp->unp_addr->sun_len);
1645 			if (unp->unp_conn != NULL &&
1646 			    unp->unp_conn->unp_addr != NULL)
1647 				bcopy(unp->unp_conn->unp_addr,
1648 				      &xu->xu_caddr,
1649 				      unp->unp_conn->unp_addr->sun_len);
1650 			bcopy(unp, &xu->xu_unp, sizeof *unp);
1651 			sotoxsocket(unp->unp_socket, &xu->xu_socket);
1652 			UNP_PCB_UNLOCK(unp);
1653 			error = SYSCTL_OUT(req, xu, sizeof *xu);
1654 		} else {
1655 			freeunp = (unp->unp_refcount == 0);
1656 			UNP_PCB_UNLOCK(unp);
1657 			if (freeunp) {
1658 				UNP_PCB_LOCK_DESTROY(unp);
1659 				uma_zfree(unp_zone, unp);
1660 			}
1661 		}
1662 	}
1663 	free(xu, M_TEMP);
1664 	if (!error) {
1665 		/*
1666 		 * Give the user an updated idea of our state.  If the
1667 		 * generation differs from what we told her before, she knows
1668 		 * that something happened while we were processing this
1669 		 * request, and it might be necessary to retry.
1670 		 */
1671 		xug->xug_gen = unp_gencnt;
1672 		xug->xug_sogen = so_gencnt;
1673 		xug->xug_count = unp_count;
1674 		error = SYSCTL_OUT(req, xug, sizeof *xug);
1675 	}
1676 	free(unp_list, M_TEMP);
1677 	free(xug, M_TEMP);
1678 	return (error);
1679 }
1680 
1681 SYSCTL_PROC(_net_local_dgram, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1682     (void *)(intptr_t)SOCK_DGRAM, 0, unp_pcblist, "S,xunpcb",
1683     "List of active local datagram sockets");
1684 SYSCTL_PROC(_net_local_stream, OID_AUTO, pcblist, CTLTYPE_OPAQUE | CTLFLAG_RD,
1685     (void *)(intptr_t)SOCK_STREAM, 0, unp_pcblist, "S,xunpcb",
1686     "List of active local stream sockets");
1687 SYSCTL_PROC(_net_local_seqpacket, OID_AUTO, pcblist,
1688     CTLTYPE_OPAQUE | CTLFLAG_RD,
1689     (void *)(intptr_t)SOCK_SEQPACKET, 0, unp_pcblist, "S,xunpcb",
1690     "List of active local seqpacket sockets");
1691 
1692 static void
1693 unp_shutdown(struct unpcb *unp)
1694 {
1695 	struct unpcb *unp2;
1696 	struct socket *so;
1697 
1698 	UNP_LINK_WLOCK_ASSERT();
1699 	UNP_PCB_LOCK_ASSERT(unp);
1700 
1701 	unp2 = unp->unp_conn;
1702 	if ((unp->unp_socket->so_type == SOCK_STREAM ||
1703 	    (unp->unp_socket->so_type == SOCK_SEQPACKET)) && unp2 != NULL) {
1704 		so = unp2->unp_socket;
1705 		if (so != NULL)
1706 			socantrcvmore(so);
1707 	}
1708 }
1709 
1710 static void
1711 unp_drop(struct unpcb *unp)
1712 {
1713 	struct socket *so = unp->unp_socket;
1714 	struct unpcb *unp2;
1715 
1716 	UNP_LINK_WLOCK_ASSERT();
1717 	UNP_PCB_LOCK_ASSERT(unp);
1718 
1719 	/*
1720 	 * Regardless of whether the socket's peer dropped the connection
1721 	 * with this socket by aborting or disconnecting, POSIX requires
1722 	 * that ECONNRESET is returned.
1723 	 */
1724 	so->so_error = ECONNRESET;
1725 	unp2 = unp->unp_conn;
1726 	if (unp2 == NULL)
1727 		return;
1728 	UNP_PCB_LOCK(unp2);
1729 	unp_disconnect(unp, unp2);
1730 	UNP_PCB_UNLOCK(unp2);
1731 }
1732 
1733 static void
1734 unp_freerights(struct filedescent **fdep, int fdcount)
1735 {
1736 	struct file *fp;
1737 	int i;
1738 
1739 	KASSERT(fdcount > 0, ("%s: fdcount %d", __func__, fdcount));
1740 
1741 	for (i = 0; i < fdcount; i++) {
1742 		fp = fdep[i]->fde_file;
1743 		filecaps_free(&fdep[i]->fde_caps);
1744 		unp_discard(fp);
1745 	}
1746 	free(fdep[0], M_FILECAPS);
1747 }
1748 
1749 static int
1750 unp_externalize(struct mbuf *control, struct mbuf **controlp, int flags)
1751 {
1752 	struct thread *td = curthread;		/* XXX */
1753 	struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1754 	int i;
1755 	int *fdp;
1756 	struct filedesc *fdesc = td->td_proc->p_fd;
1757 	struct filedescent **fdep;
1758 	void *data;
1759 	socklen_t clen = control->m_len, datalen;
1760 	int error, newfds;
1761 	u_int newlen;
1762 
1763 	UNP_LINK_UNLOCK_ASSERT();
1764 
1765 	error = 0;
1766 	if (controlp != NULL) /* controlp == NULL => free control messages */
1767 		*controlp = NULL;
1768 	while (cm != NULL) {
1769 		if (sizeof(*cm) > clen || cm->cmsg_len > clen) {
1770 			error = EINVAL;
1771 			break;
1772 		}
1773 		data = CMSG_DATA(cm);
1774 		datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1775 		if (cm->cmsg_level == SOL_SOCKET
1776 		    && cm->cmsg_type == SCM_RIGHTS) {
1777 			newfds = datalen / sizeof(*fdep);
1778 			if (newfds == 0)
1779 				goto next;
1780 			fdep = data;
1781 
1782 			/* If we're not outputting the descriptors free them. */
1783 			if (error || controlp == NULL) {
1784 				unp_freerights(fdep, newfds);
1785 				goto next;
1786 			}
1787 			FILEDESC_XLOCK(fdesc);
1788 
1789 			/*
1790 			 * Now change each pointer to an fd in the global
1791 			 * table to an integer that is the index to the local
1792 			 * fd table entry that we set up to point to the
1793 			 * global one we are transferring.
1794 			 */
1795 			newlen = newfds * sizeof(int);
1796 			*controlp = sbcreatecontrol(NULL, newlen,
1797 			    SCM_RIGHTS, SOL_SOCKET);
1798 			if (*controlp == NULL) {
1799 				FILEDESC_XUNLOCK(fdesc);
1800 				error = E2BIG;
1801 				unp_freerights(fdep, newfds);
1802 				goto next;
1803 			}
1804 
1805 			fdp = (int *)
1806 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1807 			if (fdallocn(td, 0, fdp, newfds) != 0) {
1808 				FILEDESC_XUNLOCK(fdesc);
1809 				error = EMSGSIZE;
1810 				unp_freerights(fdep, newfds);
1811 				m_freem(*controlp);
1812 				*controlp = NULL;
1813 				goto next;
1814 			}
1815 			for (i = 0; i < newfds; i++, fdp++) {
1816 				_finstall(fdesc, fdep[i]->fde_file, *fdp,
1817 				    (flags & MSG_CMSG_CLOEXEC) != 0 ? UF_EXCLOSE : 0,
1818 				    &fdep[i]->fde_caps);
1819 				unp_externalize_fp(fdep[i]->fde_file);
1820 			}
1821 			FILEDESC_XUNLOCK(fdesc);
1822 			free(fdep[0], M_FILECAPS);
1823 		} else {
1824 			/* We can just copy anything else across. */
1825 			if (error || controlp == NULL)
1826 				goto next;
1827 			*controlp = sbcreatecontrol(NULL, datalen,
1828 			    cm->cmsg_type, cm->cmsg_level);
1829 			if (*controlp == NULL) {
1830 				error = ENOBUFS;
1831 				goto next;
1832 			}
1833 			bcopy(data,
1834 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *)),
1835 			    datalen);
1836 		}
1837 		controlp = &(*controlp)->m_next;
1838 
1839 next:
1840 		if (CMSG_SPACE(datalen) < clen) {
1841 			clen -= CMSG_SPACE(datalen);
1842 			cm = (struct cmsghdr *)
1843 			    ((caddr_t)cm + CMSG_SPACE(datalen));
1844 		} else {
1845 			clen = 0;
1846 			cm = NULL;
1847 		}
1848 	}
1849 
1850 	m_freem(control);
1851 	return (error);
1852 }
1853 
1854 static void
1855 unp_zone_change(void *tag)
1856 {
1857 
1858 	uma_zone_set_max(unp_zone, maxsockets);
1859 }
1860 
1861 static void
1862 unp_init(void)
1863 {
1864 
1865 #ifdef VIMAGE
1866 	if (!IS_DEFAULT_VNET(curvnet))
1867 		return;
1868 #endif
1869 	unp_zone = uma_zcreate("unpcb", sizeof(struct unpcb), NULL, NULL,
1870 	    NULL, NULL, UMA_ALIGN_PTR, 0);
1871 	if (unp_zone == NULL)
1872 		panic("unp_init");
1873 	uma_zone_set_max(unp_zone, maxsockets);
1874 	uma_zone_set_warning(unp_zone, "kern.ipc.maxsockets limit reached");
1875 	EVENTHANDLER_REGISTER(maxsockets_change, unp_zone_change,
1876 	    NULL, EVENTHANDLER_PRI_ANY);
1877 	LIST_INIT(&unp_dhead);
1878 	LIST_INIT(&unp_shead);
1879 	LIST_INIT(&unp_sphead);
1880 	SLIST_INIT(&unp_defers);
1881 	TIMEOUT_TASK_INIT(taskqueue_thread, &unp_gc_task, 0, unp_gc, NULL);
1882 	TASK_INIT(&unp_defer_task, 0, unp_process_defers, NULL);
1883 	UNP_LINK_LOCK_INIT();
1884 	UNP_LIST_LOCK_INIT();
1885 	UNP_DEFERRED_LOCK_INIT();
1886 }
1887 
1888 static int
1889 unp_internalize(struct mbuf **controlp, struct thread *td)
1890 {
1891 	struct mbuf *control = *controlp;
1892 	struct proc *p = td->td_proc;
1893 	struct filedesc *fdesc = p->p_fd;
1894 	struct bintime *bt;
1895 	struct cmsghdr *cm = mtod(control, struct cmsghdr *);
1896 	struct cmsgcred *cmcred;
1897 	struct filedescent *fde, **fdep, *fdev;
1898 	struct file *fp;
1899 	struct timeval *tv;
1900 	struct timespec *ts;
1901 	int i, *fdp;
1902 	void *data;
1903 	socklen_t clen = control->m_len, datalen;
1904 	int error, oldfds;
1905 	u_int newlen;
1906 
1907 	UNP_LINK_UNLOCK_ASSERT();
1908 
1909 	error = 0;
1910 	*controlp = NULL;
1911 	while (cm != NULL) {
1912 		if (sizeof(*cm) > clen || cm->cmsg_level != SOL_SOCKET
1913 		    || cm->cmsg_len > clen || cm->cmsg_len < sizeof(*cm)) {
1914 			error = EINVAL;
1915 			goto out;
1916 		}
1917 		data = CMSG_DATA(cm);
1918 		datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
1919 
1920 		switch (cm->cmsg_type) {
1921 		/*
1922 		 * Fill in credential information.
1923 		 */
1924 		case SCM_CREDS:
1925 			*controlp = sbcreatecontrol(NULL, sizeof(*cmcred),
1926 			    SCM_CREDS, SOL_SOCKET);
1927 			if (*controlp == NULL) {
1928 				error = ENOBUFS;
1929 				goto out;
1930 			}
1931 			cmcred = (struct cmsgcred *)
1932 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1933 			cmcred->cmcred_pid = p->p_pid;
1934 			cmcred->cmcred_uid = td->td_ucred->cr_ruid;
1935 			cmcred->cmcred_gid = td->td_ucred->cr_rgid;
1936 			cmcred->cmcred_euid = td->td_ucred->cr_uid;
1937 			cmcred->cmcred_ngroups = MIN(td->td_ucred->cr_ngroups,
1938 			    CMGROUP_MAX);
1939 			for (i = 0; i < cmcred->cmcred_ngroups; i++)
1940 				cmcred->cmcred_groups[i] =
1941 				    td->td_ucred->cr_groups[i];
1942 			break;
1943 
1944 		case SCM_RIGHTS:
1945 			oldfds = datalen / sizeof (int);
1946 			if (oldfds == 0)
1947 				break;
1948 			/*
1949 			 * Check that all the FDs passed in refer to legal
1950 			 * files.  If not, reject the entire operation.
1951 			 */
1952 			fdp = data;
1953 			FILEDESC_SLOCK(fdesc);
1954 			for (i = 0; i < oldfds; i++, fdp++) {
1955 				fp = fget_locked(fdesc, *fdp);
1956 				if (fp == NULL) {
1957 					FILEDESC_SUNLOCK(fdesc);
1958 					error = EBADF;
1959 					goto out;
1960 				}
1961 				if (!(fp->f_ops->fo_flags & DFLAG_PASSABLE)) {
1962 					FILEDESC_SUNLOCK(fdesc);
1963 					error = EOPNOTSUPP;
1964 					goto out;
1965 				}
1966 
1967 			}
1968 
1969 			/*
1970 			 * Now replace the integer FDs with pointers to the
1971 			 * file structure and capability rights.
1972 			 */
1973 			newlen = oldfds * sizeof(fdep[0]);
1974 			*controlp = sbcreatecontrol(NULL, newlen,
1975 			    SCM_RIGHTS, SOL_SOCKET);
1976 			if (*controlp == NULL) {
1977 				FILEDESC_SUNLOCK(fdesc);
1978 				error = E2BIG;
1979 				goto out;
1980 			}
1981 			fdp = data;
1982 			fdep = (struct filedescent **)
1983 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
1984 			fdev = malloc(sizeof(*fdev) * oldfds, M_FILECAPS,
1985 			    M_WAITOK);
1986 			for (i = 0; i < oldfds; i++, fdev++, fdp++) {
1987 				fde = &fdesc->fd_ofiles[*fdp];
1988 				fdep[i] = fdev;
1989 				fdep[i]->fde_file = fde->fde_file;
1990 				filecaps_copy(&fde->fde_caps,
1991 				    &fdep[i]->fde_caps, true);
1992 				unp_internalize_fp(fdep[i]->fde_file);
1993 			}
1994 			FILEDESC_SUNLOCK(fdesc);
1995 			break;
1996 
1997 		case SCM_TIMESTAMP:
1998 			*controlp = sbcreatecontrol(NULL, sizeof(*tv),
1999 			    SCM_TIMESTAMP, SOL_SOCKET);
2000 			if (*controlp == NULL) {
2001 				error = ENOBUFS;
2002 				goto out;
2003 			}
2004 			tv = (struct timeval *)
2005 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2006 			microtime(tv);
2007 			break;
2008 
2009 		case SCM_BINTIME:
2010 			*controlp = sbcreatecontrol(NULL, sizeof(*bt),
2011 			    SCM_BINTIME, SOL_SOCKET);
2012 			if (*controlp == NULL) {
2013 				error = ENOBUFS;
2014 				goto out;
2015 			}
2016 			bt = (struct bintime *)
2017 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2018 			bintime(bt);
2019 			break;
2020 
2021 		case SCM_REALTIME:
2022 			*controlp = sbcreatecontrol(NULL, sizeof(*ts),
2023 			    SCM_REALTIME, SOL_SOCKET);
2024 			if (*controlp == NULL) {
2025 				error = ENOBUFS;
2026 				goto out;
2027 			}
2028 			ts = (struct timespec *)
2029 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2030 			nanotime(ts);
2031 			break;
2032 
2033 		case SCM_MONOTONIC:
2034 			*controlp = sbcreatecontrol(NULL, sizeof(*ts),
2035 			    SCM_MONOTONIC, SOL_SOCKET);
2036 			if (*controlp == NULL) {
2037 				error = ENOBUFS;
2038 				goto out;
2039 			}
2040 			ts = (struct timespec *)
2041 			    CMSG_DATA(mtod(*controlp, struct cmsghdr *));
2042 			nanouptime(ts);
2043 			break;
2044 
2045 		default:
2046 			error = EINVAL;
2047 			goto out;
2048 		}
2049 
2050 		controlp = &(*controlp)->m_next;
2051 		if (CMSG_SPACE(datalen) < clen) {
2052 			clen -= CMSG_SPACE(datalen);
2053 			cm = (struct cmsghdr *)
2054 			    ((caddr_t)cm + CMSG_SPACE(datalen));
2055 		} else {
2056 			clen = 0;
2057 			cm = NULL;
2058 		}
2059 	}
2060 
2061 out:
2062 	m_freem(control);
2063 	return (error);
2064 }
2065 
2066 static struct mbuf *
2067 unp_addsockcred(struct thread *td, struct mbuf *control)
2068 {
2069 	struct mbuf *m, *n, *n_prev;
2070 	struct sockcred *sc;
2071 	const struct cmsghdr *cm;
2072 	int ngroups;
2073 	int i;
2074 
2075 	ngroups = MIN(td->td_ucred->cr_ngroups, CMGROUP_MAX);
2076 	m = sbcreatecontrol(NULL, SOCKCREDSIZE(ngroups), SCM_CREDS, SOL_SOCKET);
2077 	if (m == NULL)
2078 		return (control);
2079 
2080 	sc = (struct sockcred *) CMSG_DATA(mtod(m, struct cmsghdr *));
2081 	sc->sc_uid = td->td_ucred->cr_ruid;
2082 	sc->sc_euid = td->td_ucred->cr_uid;
2083 	sc->sc_gid = td->td_ucred->cr_rgid;
2084 	sc->sc_egid = td->td_ucred->cr_gid;
2085 	sc->sc_ngroups = ngroups;
2086 	for (i = 0; i < sc->sc_ngroups; i++)
2087 		sc->sc_groups[i] = td->td_ucred->cr_groups[i];
2088 
2089 	/*
2090 	 * Unlink SCM_CREDS control messages (struct cmsgcred), since just
2091 	 * created SCM_CREDS control message (struct sockcred) has another
2092 	 * format.
2093 	 */
2094 	if (control != NULL)
2095 		for (n = control, n_prev = NULL; n != NULL;) {
2096 			cm = mtod(n, struct cmsghdr *);
2097     			if (cm->cmsg_level == SOL_SOCKET &&
2098 			    cm->cmsg_type == SCM_CREDS) {
2099     				if (n_prev == NULL)
2100 					control = n->m_next;
2101 				else
2102 					n_prev->m_next = n->m_next;
2103 				n = m_free(n);
2104 			} else {
2105 				n_prev = n;
2106 				n = n->m_next;
2107 			}
2108 		}
2109 
2110 	/* Prepend it to the head. */
2111 	m->m_next = control;
2112 	return (m);
2113 }
2114 
2115 static struct unpcb *
2116 fptounp(struct file *fp)
2117 {
2118 	struct socket *so;
2119 
2120 	if (fp->f_type != DTYPE_SOCKET)
2121 		return (NULL);
2122 	if ((so = fp->f_data) == NULL)
2123 		return (NULL);
2124 	if (so->so_proto->pr_domain != &localdomain)
2125 		return (NULL);
2126 	return sotounpcb(so);
2127 }
2128 
2129 static void
2130 unp_discard(struct file *fp)
2131 {
2132 	struct unp_defer *dr;
2133 
2134 	if (unp_externalize_fp(fp)) {
2135 		dr = malloc(sizeof(*dr), M_TEMP, M_WAITOK);
2136 		dr->ud_fp = fp;
2137 		UNP_DEFERRED_LOCK();
2138 		SLIST_INSERT_HEAD(&unp_defers, dr, ud_link);
2139 		UNP_DEFERRED_UNLOCK();
2140 		atomic_add_int(&unp_defers_count, 1);
2141 		taskqueue_enqueue(taskqueue_thread, &unp_defer_task);
2142 	} else
2143 		(void) closef(fp, (struct thread *)NULL);
2144 }
2145 
2146 static void
2147 unp_process_defers(void *arg __unused, int pending)
2148 {
2149 	struct unp_defer *dr;
2150 	SLIST_HEAD(, unp_defer) drl;
2151 	int count;
2152 
2153 	SLIST_INIT(&drl);
2154 	for (;;) {
2155 		UNP_DEFERRED_LOCK();
2156 		if (SLIST_FIRST(&unp_defers) == NULL) {
2157 			UNP_DEFERRED_UNLOCK();
2158 			break;
2159 		}
2160 		SLIST_SWAP(&unp_defers, &drl, unp_defer);
2161 		UNP_DEFERRED_UNLOCK();
2162 		count = 0;
2163 		while ((dr = SLIST_FIRST(&drl)) != NULL) {
2164 			SLIST_REMOVE_HEAD(&drl, ud_link);
2165 			closef(dr->ud_fp, NULL);
2166 			free(dr, M_TEMP);
2167 			count++;
2168 		}
2169 		atomic_add_int(&unp_defers_count, -count);
2170 	}
2171 }
2172 
2173 static void
2174 unp_internalize_fp(struct file *fp)
2175 {
2176 	struct unpcb *unp;
2177 
2178 	UNP_LINK_WLOCK();
2179 	if ((unp = fptounp(fp)) != NULL) {
2180 		unp->unp_file = fp;
2181 		unp->unp_msgcount++;
2182 	}
2183 	fhold(fp);
2184 	unp_rights++;
2185 	UNP_LINK_WUNLOCK();
2186 }
2187 
2188 static int
2189 unp_externalize_fp(struct file *fp)
2190 {
2191 	struct unpcb *unp;
2192 	int ret;
2193 
2194 	UNP_LINK_WLOCK();
2195 	if ((unp = fptounp(fp)) != NULL) {
2196 		unp->unp_msgcount--;
2197 		ret = 1;
2198 	} else
2199 		ret = 0;
2200 	unp_rights--;
2201 	UNP_LINK_WUNLOCK();
2202 	return (ret);
2203 }
2204 
2205 /*
2206  * unp_defer indicates whether additional work has been defered for a future
2207  * pass through unp_gc().  It is thread local and does not require explicit
2208  * synchronization.
2209  */
2210 static int	unp_marked;
2211 static int	unp_unreachable;
2212 
2213 static void
2214 unp_accessable(struct filedescent **fdep, int fdcount)
2215 {
2216 	struct unpcb *unp;
2217 	struct file *fp;
2218 	int i;
2219 
2220 	for (i = 0; i < fdcount; i++) {
2221 		fp = fdep[i]->fde_file;
2222 		if ((unp = fptounp(fp)) == NULL)
2223 			continue;
2224 		if (unp->unp_gcflag & UNPGC_REF)
2225 			continue;
2226 		unp->unp_gcflag &= ~UNPGC_DEAD;
2227 		unp->unp_gcflag |= UNPGC_REF;
2228 		unp_marked++;
2229 	}
2230 }
2231 
2232 static void
2233 unp_gc_process(struct unpcb *unp)
2234 {
2235 	struct socket *soa;
2236 	struct socket *so;
2237 	struct file *fp;
2238 
2239 	/* Already processed. */
2240 	if (unp->unp_gcflag & UNPGC_SCANNED)
2241 		return;
2242 	fp = unp->unp_file;
2243 
2244 	/*
2245 	 * Check for a socket potentially in a cycle.  It must be in a
2246 	 * queue as indicated by msgcount, and this must equal the file
2247 	 * reference count.  Note that when msgcount is 0 the file is NULL.
2248 	 */
2249 	if ((unp->unp_gcflag & UNPGC_REF) == 0 && fp &&
2250 	    unp->unp_msgcount != 0 && fp->f_count == unp->unp_msgcount) {
2251 		unp->unp_gcflag |= UNPGC_DEAD;
2252 		unp_unreachable++;
2253 		return;
2254 	}
2255 
2256 	/*
2257 	 * Mark all sockets we reference with RIGHTS.
2258 	 */
2259 	so = unp->unp_socket;
2260 	if ((unp->unp_gcflag & UNPGC_IGNORE_RIGHTS) == 0) {
2261 		SOCKBUF_LOCK(&so->so_rcv);
2262 		unp_scan(so->so_rcv.sb_mb, unp_accessable);
2263 		SOCKBUF_UNLOCK(&so->so_rcv);
2264 	}
2265 
2266 	/*
2267 	 * Mark all sockets in our accept queue.
2268 	 */
2269 	ACCEPT_LOCK();
2270 	TAILQ_FOREACH(soa, &so->so_comp, so_list) {
2271 		if ((sotounpcb(soa)->unp_gcflag & UNPGC_IGNORE_RIGHTS) != 0)
2272 			continue;
2273 		SOCKBUF_LOCK(&soa->so_rcv);
2274 		unp_scan(soa->so_rcv.sb_mb, unp_accessable);
2275 		SOCKBUF_UNLOCK(&soa->so_rcv);
2276 	}
2277 	ACCEPT_UNLOCK();
2278 	unp->unp_gcflag |= UNPGC_SCANNED;
2279 }
2280 
2281 static int unp_recycled;
2282 SYSCTL_INT(_net_local, OID_AUTO, recycled, CTLFLAG_RD, &unp_recycled, 0,
2283     "Number of unreachable sockets claimed by the garbage collector.");
2284 
2285 static int unp_taskcount;
2286 SYSCTL_INT(_net_local, OID_AUTO, taskcount, CTLFLAG_RD, &unp_taskcount, 0,
2287     "Number of times the garbage collector has run.");
2288 
2289 static void
2290 unp_gc(__unused void *arg, int pending)
2291 {
2292 	struct unp_head *heads[] = { &unp_dhead, &unp_shead, &unp_sphead,
2293 				    NULL };
2294 	struct unp_head **head;
2295 	struct file *f, **unref;
2296 	struct unpcb *unp;
2297 	int i, total;
2298 
2299 	unp_taskcount++;
2300 	UNP_LIST_LOCK();
2301 	/*
2302 	 * First clear all gc flags from previous runs, apart from
2303 	 * UNPGC_IGNORE_RIGHTS.
2304 	 */
2305 	for (head = heads; *head != NULL; head++)
2306 		LIST_FOREACH(unp, *head, unp_link)
2307 			unp->unp_gcflag =
2308 			    (unp->unp_gcflag & UNPGC_IGNORE_RIGHTS);
2309 
2310 	/*
2311 	 * Scan marking all reachable sockets with UNPGC_REF.  Once a socket
2312 	 * is reachable all of the sockets it references are reachable.
2313 	 * Stop the scan once we do a complete loop without discovering
2314 	 * a new reachable socket.
2315 	 */
2316 	do {
2317 		unp_unreachable = 0;
2318 		unp_marked = 0;
2319 		for (head = heads; *head != NULL; head++)
2320 			LIST_FOREACH(unp, *head, unp_link)
2321 				unp_gc_process(unp);
2322 	} while (unp_marked);
2323 	UNP_LIST_UNLOCK();
2324 	if (unp_unreachable == 0)
2325 		return;
2326 
2327 	/*
2328 	 * Allocate space for a local list of dead unpcbs.
2329 	 */
2330 	unref = malloc(unp_unreachable * sizeof(struct file *),
2331 	    M_TEMP, M_WAITOK);
2332 
2333 	/*
2334 	 * Iterate looking for sockets which have been specifically marked
2335 	 * as as unreachable and store them locally.
2336 	 */
2337 	UNP_LINK_RLOCK();
2338 	UNP_LIST_LOCK();
2339 	for (total = 0, head = heads; *head != NULL; head++)
2340 		LIST_FOREACH(unp, *head, unp_link)
2341 			if ((unp->unp_gcflag & UNPGC_DEAD) != 0) {
2342 				f = unp->unp_file;
2343 				if (unp->unp_msgcount == 0 || f == NULL ||
2344 				    f->f_count != unp->unp_msgcount)
2345 					continue;
2346 				unref[total++] = f;
2347 				fhold(f);
2348 				KASSERT(total <= unp_unreachable,
2349 				    ("unp_gc: incorrect unreachable count."));
2350 			}
2351 	UNP_LIST_UNLOCK();
2352 	UNP_LINK_RUNLOCK();
2353 
2354 	/*
2355 	 * Now flush all sockets, free'ing rights.  This will free the
2356 	 * struct files associated with these sockets but leave each socket
2357 	 * with one remaining ref.
2358 	 */
2359 	for (i = 0; i < total; i++) {
2360 		struct socket *so;
2361 
2362 		so = unref[i]->f_data;
2363 		CURVNET_SET(so->so_vnet);
2364 		sorflush(so);
2365 		CURVNET_RESTORE();
2366 	}
2367 
2368 	/*
2369 	 * And finally release the sockets so they can be reclaimed.
2370 	 */
2371 	for (i = 0; i < total; i++)
2372 		fdrop(unref[i], NULL);
2373 	unp_recycled += total;
2374 	free(unref, M_TEMP);
2375 }
2376 
2377 static void
2378 unp_dispose_mbuf(struct mbuf *m)
2379 {
2380 
2381 	if (m)
2382 		unp_scan(m, unp_freerights);
2383 }
2384 
2385 /*
2386  * Synchronize against unp_gc, which can trip over data as we are freeing it.
2387  */
2388 static void
2389 unp_dispose(struct socket *so)
2390 {
2391 	struct unpcb *unp;
2392 
2393 	unp = sotounpcb(so);
2394 	UNP_LIST_LOCK();
2395 	unp->unp_gcflag |= UNPGC_IGNORE_RIGHTS;
2396 	UNP_LIST_UNLOCK();
2397 	unp_dispose_mbuf(so->so_rcv.sb_mb);
2398 }
2399 
2400 static void
2401 unp_scan(struct mbuf *m0, void (*op)(struct filedescent **, int))
2402 {
2403 	struct mbuf *m;
2404 	struct cmsghdr *cm;
2405 	void *data;
2406 	socklen_t clen, datalen;
2407 
2408 	while (m0 != NULL) {
2409 		for (m = m0; m; m = m->m_next) {
2410 			if (m->m_type != MT_CONTROL)
2411 				continue;
2412 
2413 			cm = mtod(m, struct cmsghdr *);
2414 			clen = m->m_len;
2415 
2416 			while (cm != NULL) {
2417 				if (sizeof(*cm) > clen || cm->cmsg_len > clen)
2418 					break;
2419 
2420 				data = CMSG_DATA(cm);
2421 				datalen = (caddr_t)cm + cm->cmsg_len
2422 				    - (caddr_t)data;
2423 
2424 				if (cm->cmsg_level == SOL_SOCKET &&
2425 				    cm->cmsg_type == SCM_RIGHTS) {
2426 					(*op)(data, datalen /
2427 					    sizeof(struct filedescent *));
2428 				}
2429 
2430 				if (CMSG_SPACE(datalen) < clen) {
2431 					clen -= CMSG_SPACE(datalen);
2432 					cm = (struct cmsghdr *)
2433 					    ((caddr_t)cm + CMSG_SPACE(datalen));
2434 				} else {
2435 					clen = 0;
2436 					cm = NULL;
2437 				}
2438 			}
2439 		}
2440 		m0 = m0->m_nextpkt;
2441 	}
2442 }
2443 
2444 /*
2445  * A helper function called by VFS before socket-type vnode reclamation.
2446  * For an active vnode it clears unp_vnode pointer and decrements unp_vnode
2447  * use count.
2448  */
2449 void
2450 vfs_unp_reclaim(struct vnode *vp)
2451 {
2452 	struct unpcb *unp;
2453 	int active;
2454 
2455 	ASSERT_VOP_ELOCKED(vp, "vfs_unp_reclaim");
2456 	KASSERT(vp->v_type == VSOCK,
2457 	    ("vfs_unp_reclaim: vp->v_type != VSOCK"));
2458 
2459 	active = 0;
2460 	UNP_LINK_WLOCK();
2461 	VOP_UNP_CONNECT(vp, &unp);
2462 	if (unp == NULL)
2463 		goto done;
2464 	UNP_PCB_LOCK(unp);
2465 	if (unp->unp_vnode == vp) {
2466 		VOP_UNP_DETACH(vp);
2467 		unp->unp_vnode = NULL;
2468 		active = 1;
2469 	}
2470 	UNP_PCB_UNLOCK(unp);
2471 done:
2472 	UNP_LINK_WUNLOCK();
2473 	if (active)
2474 		vunref(vp);
2475 }
2476 
2477 #ifdef DDB
2478 static void
2479 db_print_indent(int indent)
2480 {
2481 	int i;
2482 
2483 	for (i = 0; i < indent; i++)
2484 		db_printf(" ");
2485 }
2486 
2487 static void
2488 db_print_unpflags(int unp_flags)
2489 {
2490 	int comma;
2491 
2492 	comma = 0;
2493 	if (unp_flags & UNP_HAVEPC) {
2494 		db_printf("%sUNP_HAVEPC", comma ? ", " : "");
2495 		comma = 1;
2496 	}
2497 	if (unp_flags & UNP_WANTCRED) {
2498 		db_printf("%sUNP_WANTCRED", comma ? ", " : "");
2499 		comma = 1;
2500 	}
2501 	if (unp_flags & UNP_CONNWAIT) {
2502 		db_printf("%sUNP_CONNWAIT", comma ? ", " : "");
2503 		comma = 1;
2504 	}
2505 	if (unp_flags & UNP_CONNECTING) {
2506 		db_printf("%sUNP_CONNECTING", comma ? ", " : "");
2507 		comma = 1;
2508 	}
2509 	if (unp_flags & UNP_BINDING) {
2510 		db_printf("%sUNP_BINDING", comma ? ", " : "");
2511 		comma = 1;
2512 	}
2513 }
2514 
2515 static void
2516 db_print_xucred(int indent, struct xucred *xu)
2517 {
2518 	int comma, i;
2519 
2520 	db_print_indent(indent);
2521 	db_printf("cr_version: %u   cr_uid: %u   cr_ngroups: %d\n",
2522 	    xu->cr_version, xu->cr_uid, xu->cr_ngroups);
2523 	db_print_indent(indent);
2524 	db_printf("cr_groups: ");
2525 	comma = 0;
2526 	for (i = 0; i < xu->cr_ngroups; i++) {
2527 		db_printf("%s%u", comma ? ", " : "", xu->cr_groups[i]);
2528 		comma = 1;
2529 	}
2530 	db_printf("\n");
2531 }
2532 
2533 static void
2534 db_print_unprefs(int indent, struct unp_head *uh)
2535 {
2536 	struct unpcb *unp;
2537 	int counter;
2538 
2539 	counter = 0;
2540 	LIST_FOREACH(unp, uh, unp_reflink) {
2541 		if (counter % 4 == 0)
2542 			db_print_indent(indent);
2543 		db_printf("%p  ", unp);
2544 		if (counter % 4 == 3)
2545 			db_printf("\n");
2546 		counter++;
2547 	}
2548 	if (counter != 0 && counter % 4 != 0)
2549 		db_printf("\n");
2550 }
2551 
2552 DB_SHOW_COMMAND(unpcb, db_show_unpcb)
2553 {
2554 	struct unpcb *unp;
2555 
2556         if (!have_addr) {
2557                 db_printf("usage: show unpcb <addr>\n");
2558                 return;
2559         }
2560         unp = (struct unpcb *)addr;
2561 
2562 	db_printf("unp_socket: %p   unp_vnode: %p\n", unp->unp_socket,
2563 	    unp->unp_vnode);
2564 
2565 	db_printf("unp_ino: %ju   unp_conn: %p\n", (uintmax_t)unp->unp_ino,
2566 	    unp->unp_conn);
2567 
2568 	db_printf("unp_refs:\n");
2569 	db_print_unprefs(2, &unp->unp_refs);
2570 
2571 	/* XXXRW: Would be nice to print the full address, if any. */
2572 	db_printf("unp_addr: %p\n", unp->unp_addr);
2573 
2574 	db_printf("unp_gencnt: %llu\n",
2575 	    (unsigned long long)unp->unp_gencnt);
2576 
2577 	db_printf("unp_flags: %x (", unp->unp_flags);
2578 	db_print_unpflags(unp->unp_flags);
2579 	db_printf(")\n");
2580 
2581 	db_printf("unp_peercred:\n");
2582 	db_print_xucred(2, &unp->unp_peercred);
2583 
2584 	db_printf("unp_refcount: %u\n", unp->unp_refcount);
2585 }
2586 #endif
2587