xref: /netbsd-src/sys/nfs/nfs_export.c (revision ce2c90c7c172d95d2402a5b3d96d8f8e6d138a21)
1 /*	$NetBSD: nfs_export.c,v 1.17 2006/10/12 01:32:47 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998, 2004, 2005 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9  * NASA Ames Research Center.
10  * This code is derived from software contributed to The NetBSD Foundation
11  * by Charles M. Hannum.
12  * This code is derived from software contributed to The NetBSD Foundation
13  * by Julio M. Merino Vidal.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. All advertising materials mentioning features or use of this software
24  *    must display the following acknowledgement:
25  *	This product includes software developed by the NetBSD
26  *	Foundation, Inc. and its contributors.
27  * 4. Neither the name of The NetBSD Foundation nor the names of its
28  *    contributors may be used to endorse or promote products derived
29  *    from this software without specific prior written permission.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
32  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
33  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
34  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
35  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
36  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
37  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
38  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
39  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGE.
42  */
43 
44 /*
45  * Copyright (c) 1989, 1993
46  *	The Regents of the University of California.  All rights reserved.
47  * (c) UNIX System Laboratories, Inc.
48  * All or some portions of this file are derived from material licensed
49  * to the University of California by American Telephone and Telegraph
50  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
51  * the permission of UNIX System Laboratories, Inc.
52  *
53  * Redistribution and use in source and binary forms, with or without
54  * modification, are permitted provided that the following conditions
55  * are met:
56  * 1. Redistributions of source code must retain the above copyright
57  *    notice, this list of conditions and the following disclaimer.
58  * 2. Redistributions in binary form must reproduce the above copyright
59  *    notice, this list of conditions and the following disclaimer in the
60  *    documentation and/or other materials provided with the distribution.
61  * 3. Neither the name of the University nor the names of its contributors
62  *    may be used to endorse or promote products derived from this software
63  *    without specific prior written permission.
64  *
65  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
66  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
67  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
68  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
69  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
70  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
71  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
72  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
73  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
74  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
75  * SUCH DAMAGE.
76  *
77  *	@(#)vfs_subr.c	8.13 (Berkeley) 4/18/94
78  */
79 
80 /*
81  * VFS exports list management.
82  */
83 
84 #include <sys/cdefs.h>
85 __KERNEL_RCSID(0, "$NetBSD: nfs_export.c,v 1.17 2006/10/12 01:32:47 christos Exp $");
86 
87 #include "opt_compat_netbsd.h"
88 #include "opt_inet.h"
89 
90 #include <sys/param.h>
91 #include <sys/systm.h>
92 #include <sys/queue.h>
93 #include <sys/proc.h>
94 #include <sys/mount.h>
95 #include <sys/vnode.h>
96 #include <sys/namei.h>
97 #include <sys/errno.h>
98 #include <sys/malloc.h>
99 #include <sys/domain.h>
100 #include <sys/mbuf.h>
101 #include <sys/dirent.h>
102 #include <sys/socket.h>		/* XXX for AF_MAX */
103 #include <sys/kauth.h>
104 
105 #include <net/radix.h>
106 
107 #include <netinet/in.h>
108 
109 #include <nfs/rpcv2.h>
110 #include <nfs/nfsproto.h>
111 #include <nfs/nfs.h>
112 #include <nfs/nfs_var.h>
113 
114 /*
115  * Network address lookup element.
116  */
117 struct netcred {
118 	struct	radix_node netc_rnodes[2];
119 	int	netc_refcnt;
120 	int	netc_exflags;
121 	kauth_cred_t netc_anon;
122 };
123 
124 /*
125  * Network export information.
126  */
127 struct netexport {
128 	CIRCLEQ_ENTRY(netexport) ne_list;
129 	struct mount *ne_mount;
130 	struct netcred ne_defexported;		      /* Default export */
131 	struct radix_node_head *ne_rtable[AF_MAX+1]; /* Individual exports */
132 };
133 CIRCLEQ_HEAD(, netexport) netexport_list =
134     CIRCLEQ_HEAD_INITIALIZER(netexport_list);
135 
136 /* Malloc type used by the mount<->netexport map. */
137 MALLOC_DEFINE(M_NFS_EXPORT, "nfs_export", "NFS export data");
138 
139 /* Publicly exported file system. */
140 struct nfs_public nfs_pub;
141 
142 /*
143  * Local prototypes.
144  */
145 static int init_exports(struct mount *, struct netexport **);
146 static int hang_addrlist(struct mount *, struct netexport *,
147     const struct export_args *);
148 static int sacheck(struct sockaddr *);
149 static int free_netcred(struct radix_node *, void *);
150 static int export(struct netexport *, const struct export_args *);
151 static int setpublicfs(struct mount *, struct netexport *,
152     const struct export_args *);
153 static struct netcred *netcred_lookup(struct netexport *, struct mbuf *);
154 static struct netexport *netexport_lookup(const struct mount *);
155 static struct netexport *netexport_lookup_byfsid(const fsid_t *);
156 static void netexport_clear(struct netexport *);
157 static void netexport_insert(struct netexport *);
158 static void netexport_remove(struct netexport *);
159 static void netexport_wrlock(void);
160 static void netexport_wrunlock(void);
161 
162 /*
163  * PUBLIC INTERFACE
164  */
165 
166 /*
167  * Declare and initialize the file system export hooks.
168  */
169 static void nfs_export_unmount(struct mount *);
170 
171 struct vfs_hooks nfs_export_hooks = {
172 	nfs_export_unmount
173 };
174 VFS_HOOKS_ATTACH(nfs_export_hooks);
175 
176 /*
177  * VFS unmount hook for NFS exports.
178  *
179  * Releases NFS exports list resources if the given mount point has some.
180  * As allocation happens lazily, it may be that it doesn't has this
181  * information, although it theorically should.
182  */
183 static void
184 nfs_export_unmount(struct mount *mp)
185 {
186 	struct netexport *ne;
187 
188 	KASSERT(mp != NULL);
189 
190 	netexport_wrlock();
191 	ne = netexport_lookup(mp);
192 	if (ne == NULL) {
193 		netexport_wrunlock();
194 		return;
195 	}
196 
197 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
198 	    mp->mnt_op->vfs_fhtovp != NULL);
199 	netexport_clear(ne);
200 	netexport_remove(ne);
201 	netexport_wrunlock();
202 	free(ne, M_NFS_EXPORT);
203 }
204 
205 /*
206  * Atomically set the NFS exports list of the given file system, replacing
207  * it with a new list of entries.
208  *
209  * Returns zero on success or an appropriate error code otherwise.
210  *
211  * Helper function for the nfssvc(2) system call (NFSSVC_SETEXPORTSLIST
212  * command).
213  */
214 int
215 mountd_set_exports_list(const struct mountd_exports_list *mel, struct lwp *l)
216 {
217 	int error;
218 #ifdef notyet
219 	/* XXX: See below to see the reason why this is disabled. */
220 	size_t i;
221 #endif
222 	struct mount *mp;
223 	struct netexport *ne;
224 	struct nameidata nd;
225 	struct vnode *vp;
226 	struct fid *fid;
227 	size_t fid_size;
228 
229 	if (kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
230 	    &l->l_acflag) != 0)
231 		return EPERM;
232 
233 	/* Lookup the file system path. */
234 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE, mel->mel_path, l);
235 	error = namei(&nd);
236 	if (error != 0)
237 		return error;
238 	vp = nd.ni_vp;
239 	mp = vp->v_mount;
240 
241 	/* The selected file system may not support NFS exports, so ensure
242 	 * it does. */
243 	if (mp->mnt_op->vfs_vptofh == NULL || mp->mnt_op->vfs_fhtovp == NULL) {
244 		error = EOPNOTSUPP;
245 		goto out_locked;
246 	}
247 	fid_size = 0;
248 	if ((error = VFS_VPTOFH(vp, NULL, &fid_size)) == E2BIG) {
249 		fid = malloc(fid_size, M_TEMP, M_NOWAIT);
250 		if (fid != NULL) {
251 			error = VFS_VPTOFH(vp, fid, &fid_size);
252 			free(fid, M_TEMP);
253 		}
254 	}
255 	if (error != 0) {
256 		error = EOPNOTSUPP;
257 		goto out_locked;
258 	}
259 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
260 	    mp->mnt_op->vfs_fhtovp != NULL);
261 
262 	/* Mark the file system busy. */
263 	error = vfs_busy(mp, LK_NOWAIT, NULL);
264 	if (error != 0)
265 		goto out_locked;
266 
267 	netexport_wrlock();
268 	ne = netexport_lookup(mp);
269 	if (ne == NULL) {
270 		error = init_exports(mp, &ne);
271 		if (error != 0) {
272 			goto out_locked2;
273 		}
274 	}
275 
276 	KASSERT(ne != NULL);
277 	KASSERT(ne->ne_mount == mp);
278 
279 	/*
280 	 * XXX: The part marked as 'notyet' works fine from the kernel's
281 	 * point of view, in the sense that it is able to atomically update
282 	 * the complete exports list for a file system.  However, supporting
283 	 * this in mountd(8) requires a lot of work; so, for now, keep the
284 	 * old behavior of updating a single entry per call.
285 	 *
286 	 * When mountd(8) is fixed, just remove the second branch of this
287 	 * preprocessor conditional and enable the first one.
288 	 */
289 #ifdef notyet
290 	netexport_clear(ne);
291 	for (i = 0; error == 0 && i < mel->mel_nexports; i++)
292 		error = export(ne, &mel->mel_exports[i]);
293 #else
294 	if (mel->mel_nexports == 0)
295 		netexport_clear(ne);
296 	else if (mel->mel_nexports == 1)
297 		error = export(ne, &mel->mel_exports[0]);
298 	else {
299 		printf("mountd_set_exports_list: Cannot set more than one "
300 		    "entry at once (unimplemented)\n");
301 		error = EOPNOTSUPP;
302 	}
303 #endif
304 
305 out_locked2:
306 	netexport_wrunlock();
307 	vfs_unbusy(mp);
308 
309 out_locked:
310 	vput(vp);
311 
312 	return error;
313 }
314 
315 static void
316 netexport_insert(struct netexport *ne)
317 {
318 
319 	CIRCLEQ_INSERT_HEAD(&netexport_list, ne, ne_list);
320 }
321 
322 static void
323 netexport_remove(struct netexport *ne)
324 {
325 
326 	CIRCLEQ_REMOVE(&netexport_list, ne, ne_list);
327 }
328 
329 static struct netexport *
330 netexport_lookup(const struct mount *mp)
331 {
332 	struct netexport *ne;
333 
334 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
335 		if (ne->ne_mount == mp) {
336 			goto done;
337 		}
338 	}
339 	ne = NULL;
340 done:
341 	return ne;
342 }
343 
344 static struct netexport *
345 netexport_lookup_byfsid(const fsid_t *fsid)
346 {
347 	struct netexport *ne;
348 
349 	CIRCLEQ_FOREACH(ne, &netexport_list, ne_list) {
350 		const struct mount *mp = ne->ne_mount;
351 
352 		if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] &&
353 		    mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) {
354 			goto done;
355 		}
356 	}
357 	ne = NULL;
358 done:
359 
360 	return ne;
361 }
362 
363 /*
364  * Check if the file system specified by the 'mp' mount structure is
365  * exported to a client with 'anon' anonymous credentials.  The 'mb'
366  * argument is an mbuf containing the network address of the client.
367  * The return parameters for the export flags for the client are returned
368  * in the address specified by 'wh'.
369  *
370  * This function is used exclusively by the NFS server.  It is generally
371  * invoked before VFS_FHTOVP to validate that client has access to the
372  * file system.
373  */
374 
375 int
376 netexport_check(const fsid_t *fsid, struct mbuf *mb, struct mount **mpp,
377     int *wh, kauth_cred_t *anon)
378 {
379 	struct netexport *ne;
380 	struct netcred *np;
381 
382 	ne = netexport_lookup_byfsid(fsid);
383 	if (ne == NULL) {
384 		return EACCES;
385 	}
386 	np = netcred_lookup(ne, mb);
387 	if (np == NULL) {
388 		return EACCES;
389 	}
390 
391 	*mpp = ne->ne_mount;
392 	*wh = np->netc_exflags;
393 	*anon = np->netc_anon;
394 
395 	return 0;
396 }
397 
398 #ifdef COMPAT_30
399 /*
400  * Handles legacy export requests.  In this case, the export information
401  * is hardcoded in a specific place of the mount arguments structure (given
402  * in data); the request for an update is given through the fspec field
403  * (also in a known location), which must be a null pointer.
404  *
405  * Returns EJUSTRETURN if the given command was not a export request.
406  * Otherwise, returns 0 on success or an appropriate error code otherwise.
407  */
408 int
409 nfs_update_exports_30(struct mount *mp __unused, const char *path, void *data,
410     struct lwp *l)
411 {
412 	int error;
413 	struct {
414 		const char *fspec;
415 		struct export_args30 eargs;
416 	} args;
417 	struct mountd_exports_list mel;
418 
419 	mel.mel_path = path;
420 
421 	error = copyin(data, &args, sizeof(args));
422 	if (error != 0)
423 		return EJUSTRETURN;
424 
425 	if (args.fspec != NULL)
426 		return EJUSTRETURN;
427 
428 	if (args.eargs.ex_flags & 0x00020000) {
429 		/* Request to delete exports.  The mask above holds the
430 		 * value that used to be in MNT_DELEXPORT. */
431 		mel.mel_nexports = 0;
432 	} else {
433 		struct export_args eargs;
434 
435 		/* The following assumes export_args has not changed since
436 		 * export_args30. */
437 		memcpy(&eargs, &args.eargs, sizeof(struct export_args));
438 
439 		mel.mel_nexports = 1;
440 		mel.mel_exports = &eargs;
441 	}
442 
443 	return mountd_set_exports_list(&mel, l);
444 }
445 #endif
446 
447 /*
448  * INTERNAL FUNCTIONS
449  */
450 
451 /*
452  * Initializes NFS exports for the file system given in 'mp' if it supports
453  * file handles; this is determined by checking whether mp's vfs_vptofh and
454  * vfs_fhtovp operations are NULL or not.
455  *
456  * If successful, returns 0 and sets *mnpp to the address of the new
457  * mount_netexport_pair item; otherwise returns and appropriate error code
458  * and *mnpp remains unmodified.
459  */
460 static int
461 init_exports(struct mount *mp, struct netexport **nep)
462 {
463 	int error;
464 	struct export_args ea;
465 	struct netexport *ne;
466 
467 	KASSERT(mp != NULL);
468 	KASSERT(mp->mnt_op->vfs_vptofh != NULL &&
469 	    mp->mnt_op->vfs_fhtovp != NULL);
470 
471 	/* Ensure that we do not already have this mount point. */
472 	KASSERT(netexport_lookup(mp) == NULL);
473 
474 	ne = malloc(sizeof(*ne), M_NFS_EXPORT, M_WAITOK | M_ZERO);
475 	ne->ne_mount = mp;
476 
477 	/* Set the default export entry.  Handled internally by export upon
478 	 * first call. */
479 	memset(&ea, 0, sizeof(ea));
480 	ea.ex_root = -2;
481 	if (mp->mnt_flag & MNT_RDONLY)
482 		ea.ex_flags |= MNT_EXRDONLY;
483 	error = export(ne, &ea);
484 	if (error != 0) {
485 		free(ne, M_NFS_EXPORT);
486 	} else {
487 		netexport_insert(ne);
488 		*nep = ne;
489 	}
490 
491 	return error;
492 }
493 
494 /*
495  * Build hash lists of net addresses and hang them off the mount point.
496  * Called by export() to set up a new entry in the lists of export
497  * addresses.
498  */
499 static int
500 hang_addrlist(struct mount *mp, struct netexport *nep,
501     const struct export_args *argp)
502 {
503 	int error, i;
504 	struct netcred *np, *enp;
505 	struct radix_node_head *rnh;
506 	struct sockaddr *saddr, *smask;
507 	struct domain *dom;
508 
509 	smask = NULL;
510 
511 	if (argp->ex_addrlen == 0) {
512 		if (mp->mnt_flag & MNT_DEFEXPORTED)
513 			return EPERM;
514 		np = &nep->ne_defexported;
515 		KASSERT(np->netc_anon == NULL);
516 		np->netc_anon = kauth_cred_alloc();
517 		np->netc_exflags = argp->ex_flags;
518 		kauth_cred_uucvt(np->netc_anon, &argp->ex_anon);
519 		mp->mnt_flag |= MNT_DEFEXPORTED;
520 		return 0;
521 	}
522 
523 	if (argp->ex_addrlen > MLEN || argp->ex_masklen > MLEN)
524 		return EINVAL;
525 
526 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
527 	np = malloc(i, M_NETADDR, M_WAITOK | M_ZERO);
528 	np->netc_anon = kauth_cred_alloc();
529 	saddr = (struct sockaddr *)(np + 1);
530 	error = copyin(argp->ex_addr, saddr, argp->ex_addrlen);
531 	if (error)
532 		goto out;
533 	if (saddr->sa_len > argp->ex_addrlen)
534 		saddr->sa_len = argp->ex_addrlen;
535 	if (sacheck(saddr) == -1)
536 		return EINVAL;
537 	if (argp->ex_masklen) {
538 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
539 		error = copyin(argp->ex_mask, smask, argp->ex_masklen);
540 		if (error)
541 			goto out;
542 		if (smask->sa_len > argp->ex_masklen)
543 			smask->sa_len = argp->ex_masklen;
544 		if (smask->sa_family != saddr->sa_family)
545 			return EINVAL;
546 		if (sacheck(smask) == -1)
547 			return EINVAL;
548 	}
549 	i = saddr->sa_family;
550 	if ((rnh = nep->ne_rtable[i]) == 0) {
551 		/*
552 		 * Seems silly to initialize every AF when most are not
553 		 * used, do so on demand here
554 		 */
555 		DOMAIN_FOREACH(dom) {
556 			if (dom->dom_family == i && dom->dom_rtattach) {
557 				dom->dom_rtattach((void **)&nep->ne_rtable[i],
558 					dom->dom_rtoffset);
559 				break;
560 			}
561 		}
562 		if ((rnh = nep->ne_rtable[i]) == 0) {
563 			error = ENOBUFS;
564 			goto out;
565 		}
566 	}
567 
568 	enp = (struct netcred *)(*rnh->rnh_addaddr)(saddr, smask, rnh,
569 	    np->netc_rnodes);
570 	if (enp != np) {
571 		if (enp == NULL) {
572 			enp = (struct netcred *)(*rnh->rnh_lookup)(saddr,
573 			    smask, rnh);
574 			if (enp == NULL) {
575 				error = EPERM;
576 				goto out;
577 			}
578 		} else
579 			enp->netc_refcnt++;
580 
581 		goto check;
582 	} else
583 		enp->netc_refcnt = 1;
584 
585 	np->netc_exflags = argp->ex_flags;
586 	kauth_cred_uucvt(np->netc_anon, &argp->ex_anon);
587 	return 0;
588 check:
589 	if (enp->netc_exflags != argp->ex_flags ||
590 	    kauth_cred_uucmp(enp->netc_anon, &argp->ex_anon) != 0)
591 		error = EPERM;
592 	else
593 		error = 0;
594 out:
595 	KASSERT(np->netc_anon != NULL);
596 	kauth_cred_free(np->netc_anon);
597 	free(np, M_NETADDR);
598 	return error;
599 }
600 
601 /*
602  * Ensure that the address stored in 'sa' is valid.
603  * Returns zero on success, otherwise -1.
604  */
605 static int
606 sacheck(struct sockaddr *sa)
607 {
608 
609 	switch (sa->sa_family) {
610 #ifdef INET
611 	case AF_INET: {
612 		struct sockaddr_in *sin = (struct sockaddr_in *)sa;
613 		char *p = (char *)sin->sin_zero;
614 		size_t i;
615 
616 		if (sin->sin_len != sizeof(*sin))
617 			return -1;
618 		if (sin->sin_port != 0)
619 			return -1;
620 		for (i = 0; i < sizeof(sin->sin_zero); i++)
621 			if (*p++ != '\0')
622 				return -1;
623 		return 0;
624 	}
625 #endif
626 #ifdef INET6
627 	case AF_INET6: {
628 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sa;
629 
630 		if (sin6->sin6_len != sizeof(*sin6))
631 			return -1;
632 		if (sin6->sin6_port != 0)
633 			return -1;
634 		return 0;
635 	}
636 #endif
637 	default:
638 		return -1;
639 	}
640 }
641 
642 /*
643  * Free the netcred object pointed to by the 'rn' radix node.
644  * 'w' holds a pointer to the radix tree head.
645  */
646 static int
647 free_netcred(struct radix_node *rn, void *w)
648 {
649 	struct radix_node_head *rnh = (struct radix_node_head *)w;
650 	struct netcred *np = (struct netcred *)(void *)rn;
651 
652 	(*rnh->rnh_deladdr)(rn->rn_key, rn->rn_mask, rnh);
653 	if (--(np->netc_refcnt) <= 0) {
654 		KASSERT(np->netc_anon != NULL);
655 		kauth_cred_free(np->netc_anon);
656 		free(np, M_NETADDR);
657 	}
658 	return 0;
659 }
660 
661 /*
662  * Clears the exports list for a given file system.
663  */
664 static void
665 netexport_clear(struct netexport *ne)
666 {
667 	struct radix_node_head *rnh;
668 	struct mount *mp = ne->ne_mount;
669 	int i;
670 
671 	if (mp->mnt_flag & MNT_EXPUBLIC) {
672 		setpublicfs(NULL, NULL, NULL);
673 		mp->mnt_flag &= ~MNT_EXPUBLIC;
674 	}
675 
676 	for (i = 0; i <= AF_MAX; i++) {
677 		if ((rnh = ne->ne_rtable[i]) != NULL) {
678 			(*rnh->rnh_walktree)(rnh, free_netcred, rnh);
679 			free(rnh, M_RTABLE);
680 			ne->ne_rtable[i] = NULL;
681 		}
682 	}
683 
684 	if ((mp->mnt_flag & MNT_DEFEXPORTED) != 0) {
685 		struct netcred *np = &ne->ne_defexported;
686 
687 		KASSERT(np->netc_anon != NULL);
688 		kauth_cred_free(np->netc_anon);
689 		np->netc_anon = NULL;
690 	} else {
691 		KASSERT(ne->ne_defexported.netc_anon == NULL);
692 	}
693 
694 	mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
695 }
696 
697 /*
698  * Add a new export entry (described by an export_args structure) to the
699  * given file system.
700  */
701 static int
702 export(struct netexport *nep, const struct export_args *argp)
703 {
704 	struct mount *mp = nep->ne_mount;
705 	int error;
706 
707 	if (argp->ex_flags & MNT_EXPORTED) {
708 		if (argp->ex_flags & MNT_EXPUBLIC) {
709 			if ((error = setpublicfs(mp, nep, argp)) != 0)
710 				return error;
711 			mp->mnt_flag |= MNT_EXPUBLIC;
712 		}
713 		if ((error = hang_addrlist(mp, nep, argp)) != 0)
714 			return error;
715 		mp->mnt_flag |= MNT_EXPORTED;
716 	}
717 	return 0;
718 }
719 
720 /*
721  * Set the publicly exported filesystem (WebNFS).  Currently, only
722  * one public filesystem is possible in the spec (RFC 2054 and 2055)
723  */
724 static int
725 setpublicfs(struct mount *mp, struct netexport *nep __unused,
726     const struct export_args *argp)
727 {
728 	char *cp;
729 	int error;
730 	struct vnode *rvp;
731 	size_t fhsize;
732 
733 	/*
734 	 * mp == NULL -> invalidate the current info, the FS is
735 	 * no longer exported. May be called from either export
736 	 * or unmount, so check if it hasn't already been done.
737 	 */
738 	if (mp == NULL) {
739 		if (nfs_pub.np_valid) {
740 			nfs_pub.np_valid = 0;
741 			if (nfs_pub.np_handle != NULL) {
742 				free(nfs_pub.np_handle, M_TEMP);
743 				nfs_pub.np_handle = NULL;
744 			}
745 			if (nfs_pub.np_index != NULL) {
746 				FREE(nfs_pub.np_index, M_TEMP);
747 				nfs_pub.np_index = NULL;
748 			}
749 		}
750 		return 0;
751 	}
752 
753 	/*
754 	 * Only one allowed at a time.
755 	 */
756 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
757 		return EBUSY;
758 
759 	/*
760 	 * Get real filehandle for root of exported FS.
761 	 */
762 	if ((error = VFS_ROOT(mp, &rvp)))
763 		return error;
764 
765 	fhsize = 0;
766 	error = vfs_composefh(rvp, NULL, &fhsize);
767 	if (error != E2BIG)
768 		return error;
769 	nfs_pub.np_handle = malloc(fhsize, M_TEMP, M_NOWAIT);
770 	if (nfs_pub.np_handle == NULL)
771 		error = ENOMEM;
772 	else
773 		error = vfs_composefh(rvp, nfs_pub.np_handle, &fhsize);
774 	if (error)
775 		return error;
776 
777 	vput(rvp);
778 
779 	/*
780 	 * If an indexfile was specified, pull it in.
781 	 */
782 	if (argp->ex_indexfile != NULL) {
783 		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
784 		    M_WAITOK);
785 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
786 		    MAXNAMLEN, (size_t *)0);
787 		if (!error) {
788 			/*
789 			 * Check for illegal filenames.
790 			 */
791 			for (cp = nfs_pub.np_index; *cp; cp++) {
792 				if (*cp == '/') {
793 					error = EINVAL;
794 					break;
795 				}
796 			}
797 		}
798 		if (error) {
799 			FREE(nfs_pub.np_index, M_TEMP);
800 			return error;
801 		}
802 	}
803 
804 	nfs_pub.np_mount = mp;
805 	nfs_pub.np_valid = 1;
806 	return 0;
807 }
808 
809 /*
810  * Lookup an export entry in the exports list that matches the address
811  * stored in 'nam'.  If no entry is found, the default one is used instead
812  * (if available).
813  */
814 static struct netcred *
815 netcred_lookup(struct netexport *ne, struct mbuf *nam)
816 {
817 	struct netcred *np;
818 	struct radix_node_head *rnh;
819 	struct sockaddr *saddr;
820 
821 	if ((ne->ne_mount->mnt_flag & MNT_EXPORTED) == 0) {
822 		return NULL;
823 	}
824 
825 	/*
826 	 * Lookup in the export list first.
827 	 */
828 	np = NULL;
829 	if (nam != NULL) {
830 		saddr = mtod(nam, struct sockaddr *);
831 		rnh = ne->ne_rtable[saddr->sa_family];
832 		if (rnh != NULL) {
833 			np = (struct netcred *)
834 				(*rnh->rnh_matchaddr)((caddr_t)saddr,
835 						      rnh);
836 			if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
837 				np = NULL;
838 		}
839 	}
840 	/*
841 	 * If no address match, use the default if it exists.
842 	 */
843 	if (np == NULL && ne->ne_mount->mnt_flag & MNT_DEFEXPORTED)
844 		np = &ne->ne_defexported;
845 
846 	return np;
847 }
848 
849 static struct lock netexport_lock = LOCK_INITIALIZER(PVFS, "netexp", 0, 0);
850 
851 void
852 netexport_rdlock(void)
853 {
854 
855 	lockmgr(&netexport_lock, LK_SHARED, NULL);
856 }
857 
858 void
859 netexport_rdunlock(void)
860 {
861 
862 	lockmgr(&netexport_lock, LK_RELEASE, NULL);
863 }
864 
865 static void
866 netexport_wrlock(void)
867 {
868 
869 	lockmgr(&netexport_lock, LK_EXCLUSIVE, NULL);
870 }
871 
872 static void
873 netexport_wrunlock(void)
874 {
875 
876 	lockmgr(&netexport_lock, LK_RELEASE, NULL);
877 }
878