xref: /openbsd-src/sys/nfs/nfs_socket.c (revision 365a24f4da5afba104b57ff7e590a1f7b1edb1dc)
1 /*	$OpenBSD: nfs_socket.c,v 1.146 2024/03/22 07:15:04 claudio Exp $	*/
2 /*	$NetBSD: nfs_socket.c,v 1.27 1996/04/15 20:20:00 thorpej Exp $	*/
3 
4 /*
5  * Copyright (c) 1989, 1991, 1993, 1995
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Rick Macklem at The University of Guelph.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)nfs_socket.c	8.5 (Berkeley) 3/30/95
36  */
37 
38 /*
39  * Socket operations for use by nfs
40  */
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/proc.h>
45 #include <sys/mount.h>
46 #include <sys/kernel.h>
47 #include <sys/mbuf.h>
48 #include <sys/vnode.h>
49 #include <sys/protosw.h>
50 #include <sys/signalvar.h>
51 #include <sys/socket.h>
52 #include <sys/socketvar.h>
53 #include <sys/syslog.h>
54 #include <sys/tprintf.h>
55 #include <sys/namei.h>
56 #include <sys/pool.h>
57 #include <sys/queue.h>
58 
59 #include <netinet/in.h>
60 #include <netinet/tcp.h>
61 
62 #include <nfs/rpcv2.h>
63 #include <nfs/nfsproto.h>
64 #include <nfs/nfs.h>
65 #include <nfs/xdr_subs.h>
66 #include <nfs/nfsm_subs.h>
67 #include <nfs/nfsmount.h>
68 #include <nfs/nfs_var.h>
69 
70 /* External data, mostly RPC constants in XDR form. */
71 extern u_int32_t rpc_reply, rpc_msgdenied, rpc_mismatch, rpc_vers,
72 	rpc_auth_unix, rpc_msgaccepted, rpc_call, rpc_autherr;
73 extern u_int32_t nfs_prog;
74 extern struct nfsstats nfsstats;
75 extern int nfsv3_procid[NFS_NPROCS];
76 extern int nfs_ticks;
77 
78 extern struct pool nfsrv_descript_pl;
79 
80 /*
81  * There is a congestion window for outstanding rpcs maintained per mount
82  * point. The cwnd size is adjusted in roughly the way that:
83  * Van Jacobson, Congestion avoidance and Control, In "Proceedings of
84  * SIGCOMM '88". ACM, August 1988.
85  * describes for TCP. The cwnd size is chopped in half on a retransmit timeout
86  * and incremented by 1/cwnd when each rpc reply is received and a full cwnd
87  * of rpcs is in progress.
88  * (The sent count and cwnd are scaled for integer arith.)
89  * Variants of "slow start" were tried and were found to be too much of a
90  * performance hit (ave. rtt 3 times larger),
91  * I suspect due to the large rtt that nfs rpcs have.
92  */
93 #define	NFS_CWNDSCALE	256
94 #define	NFS_MAXCWND	(NFS_CWNDSCALE * 32)
95 int nfs_backoff[8] = { 2, 4, 8, 16, 32, 64, 128, 256 };
96 
97 /* RTT estimator */
98 enum nfs_rto_timers nfs_ptimers[NFS_NPROCS] = {
99 	NFS_DEFAULT_TIMER,	/* NULL */
100 	NFS_GETATTR_TIMER,	/* GETATTR */
101 	NFS_DEFAULT_TIMER,	/* SETATTR */
102 	NFS_LOOKUP_TIMER,	/* LOOKUP */
103 	NFS_GETATTR_TIMER,	/* ACCESS */
104 	NFS_READ_TIMER,		/* READLINK */
105 	NFS_READ_TIMER,		/* READ */
106 	NFS_WRITE_TIMER,	/* WRITE */
107 	NFS_DEFAULT_TIMER,	/* CREATE */
108 	NFS_DEFAULT_TIMER,	/* MKDIR */
109 	NFS_DEFAULT_TIMER,	/* SYMLINK */
110 	NFS_DEFAULT_TIMER,	/* MKNOD */
111 	NFS_DEFAULT_TIMER,	/* REMOVE */
112 	NFS_DEFAULT_TIMER,	/* RMDIR */
113 	NFS_DEFAULT_TIMER,	/* RENAME */
114 	NFS_DEFAULT_TIMER,	/* LINK */
115 	NFS_READ_TIMER,		/* READDIR */
116 	NFS_READ_TIMER,		/* READDIRPLUS */
117 	NFS_DEFAULT_TIMER,	/* FSSTAT */
118 	NFS_DEFAULT_TIMER,	/* FSINFO */
119 	NFS_DEFAULT_TIMER,	/* PATHCONF */
120 	NFS_DEFAULT_TIMER,	/* COMMIT */
121 	NFS_DEFAULT_TIMER,	/* NOOP */
122 };
123 
124 void nfs_init_rtt(struct nfsmount *);
125 void nfs_update_rtt(struct nfsreq *);
126 int  nfs_estimate_rto(struct nfsmount *, u_int32_t procnum);
127 
128 void nfs_realign(struct mbuf **, int);
129 void nfs_realign_fixup(struct mbuf *, struct mbuf *, unsigned int *);
130 
131 int nfs_rcvlock(struct nfsreq *);
132 int nfs_receive(struct nfsreq *, struct mbuf **, struct mbuf **);
133 int nfs_reconnect(struct nfsreq *);
134 int nfs_reply(struct nfsreq *);
135 void nfs_msg(struct nfsreq *, char *);
136 void nfs_rcvunlock(int *);
137 
138 int nfsrv_getstream(struct nfssvc_sock *, int);
139 
140 unsigned int nfs_realign_test = 0;
141 unsigned int nfs_realign_count = 0;
142 
143 /* Initialize the RTT estimator state for a new mount point. */
144 void
145 nfs_init_rtt(struct nfsmount *nmp)
146 {
147 	int i;
148 
149 	for (i = 0; i < NFS_MAX_TIMER; i++)
150 		nmp->nm_srtt[i] = NFS_INITRTT;
151 	for (i = 0; i < NFS_MAX_TIMER; i++)
152 		nmp->nm_sdrtt[i] = 0;
153 }
154 
155 /*
156  * Update a mount point's RTT estimator state using data from the
157  * passed-in request.
158  *
159  * Use a gain of 0.125 on the mean and a gain of 0.25 on the deviation.
160  *
161  * NB: Since the timer resolution of NFS_HZ is so course, it can often
162  * result in r_rtt == 0. Since r_rtt == N means that the actual RTT is
163  * between N + dt and N + 2 - dt ticks, add 1 before calculating the
164  * update values.
165  */
166 void
167 nfs_update_rtt(struct nfsreq *rep)
168 {
169 	int t1 = rep->r_rtt + 1;
170 	int index = nfs_ptimers[rep->r_procnum] - 1;
171 	int *srtt = &rep->r_nmp->nm_srtt[index];
172 	int *sdrtt = &rep->r_nmp->nm_sdrtt[index];
173 
174 	t1 -= *srtt >> 3;
175 	*srtt += t1;
176 	if (t1 < 0)
177 		t1 = -t1;
178 	t1 -= *sdrtt >> 2;
179 	*sdrtt += t1;
180 }
181 
182 /*
183  * Estimate RTO for an NFS RPC sent via an unreliable datagram.
184  *
185  * Use the mean and mean deviation of RTT for the appropriate type
186  * of RPC for the frequent RPCs and a default for the others.
187  * The justification for doing "other" this way is that these RPCs
188  * happen so infrequently that timer est. would probably be stale.
189  * Also, since many of these RPCs are non-idempotent, a conservative
190  * timeout is desired.
191  *
192  * getattr, lookup - A+2D
193  * read, write     - A+4D
194  * other           - nm_timeo
195  */
196 int
197 nfs_estimate_rto(struct nfsmount *nmp, u_int32_t procnum)
198 {
199 	enum nfs_rto_timers timer = nfs_ptimers[procnum];
200 	int index = timer - 1;
201 	int rto;
202 
203 	switch (timer) {
204 	case NFS_GETATTR_TIMER:
205 	case NFS_LOOKUP_TIMER:
206 		rto = ((nmp->nm_srtt[index] + 3) >> 2) +
207 				((nmp->nm_sdrtt[index] + 1) >> 1);
208 		break;
209 	case NFS_READ_TIMER:
210 	case NFS_WRITE_TIMER:
211 		rto = ((nmp->nm_srtt[index] + 7) >> 3) +
212 				(nmp->nm_sdrtt[index] + 1);
213 		break;
214 	default:
215 		rto = nmp->nm_timeo;
216 		return (rto);
217 	}
218 
219 	if (rto < NFS_MINRTO)
220 		rto = NFS_MINRTO;
221 	else if (rto > NFS_MAXRTO)
222 		rto = NFS_MAXRTO;
223 
224 	return (rto);
225 }
226 
227 
228 
229 /*
230  * Initialize sockets and congestion for a new NFS connection.
231  * We do not free the sockaddr if error.
232  */
233 int
234 nfs_connect(struct nfsmount *nmp, struct nfsreq *rep)
235 {
236 	struct socket *so;
237 	int error, rcvreserve, sndreserve;
238 	struct sockaddr *saddr;
239 	struct sockaddr_in *sin;
240 	struct mbuf *nam = NULL, *mopt = NULL;
241 
242 	if (!(nmp->nm_sotype == SOCK_DGRAM || nmp->nm_sotype == SOCK_STREAM))
243 		return (EINVAL);
244 
245 	nmp->nm_so = NULL;
246 	saddr = mtod(nmp->nm_nam, struct sockaddr *);
247 	error = socreate(saddr->sa_family, &nmp->nm_so, nmp->nm_sotype,
248 	    nmp->nm_soproto);
249 	if (error) {
250 		nfs_disconnect(nmp);
251 		return (error);
252 	}
253 
254 	/* Allocate mbufs possibly waiting before grabbing the socket lock. */
255 	if (nmp->nm_sotype == SOCK_STREAM || saddr->sa_family == AF_INET)
256 		MGET(mopt, M_WAIT, MT_SOOPTS);
257 	if (saddr->sa_family == AF_INET)
258 		MGET(nam, M_WAIT, MT_SONAME);
259 
260 	so = nmp->nm_so;
261 	nmp->nm_soflags = so->so_proto->pr_flags;
262 
263 	/*
264 	 * Some servers require that the client port be a reserved port number.
265 	 * We always allocate a reserved port, as this prevents filehandle
266 	 * disclosure through UDP port capture.
267 	 */
268 	if (saddr->sa_family == AF_INET) {
269 		int *ip;
270 
271 		mopt->m_len = sizeof(int);
272 		ip = mtod(mopt, int *);
273 		*ip = IP_PORTRANGE_LOW;
274 		error = sosetopt(so, IPPROTO_IP, IP_PORTRANGE, mopt);
275 		if (error)
276 			goto bad;
277 
278 		sin = mtod(nam, struct sockaddr_in *);
279 		memset(sin, 0, sizeof(*sin));
280 		sin->sin_len = nam->m_len = sizeof(struct sockaddr_in);
281 		sin->sin_family = AF_INET;
282 		sin->sin_addr.s_addr = INADDR_ANY;
283 		sin->sin_port = htons(0);
284 		solock(so);
285 		error = sobind(so, nam, &proc0);
286 		sounlock(so);
287 		if (error)
288 			goto bad;
289 
290 		mopt->m_len = sizeof(int);
291 		ip = mtod(mopt, int *);
292 		*ip = IP_PORTRANGE_DEFAULT;
293 		error = sosetopt(so, IPPROTO_IP, IP_PORTRANGE, mopt);
294 		if (error)
295 			goto bad;
296 	}
297 
298 	/*
299 	 * Protocols that do not require connections may be optionally left
300 	 * unconnected for servers that reply from a port other than NFS_PORT.
301 	 */
302 	if (nmp->nm_flag & NFSMNT_NOCONN) {
303 		if (nmp->nm_soflags & PR_CONNREQUIRED) {
304 			error = ENOTCONN;
305 			goto bad;
306 		}
307 	} else {
308 		solock(so);
309 		error = soconnect(so, nmp->nm_nam);
310 		if (error)
311 			goto bad_locked;
312 
313 		/*
314 		 * Wait for the connection to complete. Cribbed from the
315 		 * connect system call but with the wait timing out so
316 		 * that interruptible mounts don't hang here for a long time.
317 		 */
318 		while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
319 			sosleep_nsec(so, &so->so_timeo, PSOCK, "nfscon",
320 			    SEC_TO_NSEC(2));
321 			if ((so->so_state & SS_ISCONNECTING) &&
322 			    so->so_error == 0 && rep &&
323 			    (error = nfs_sigintr(nmp, rep, rep->r_procp)) != 0){
324 				so->so_state &= ~SS_ISCONNECTING;
325 				goto bad_locked;
326 			}
327 		}
328 		if (so->so_error) {
329 			error = so->so_error;
330 			so->so_error = 0;
331 			goto bad_locked;
332 		}
333 		sounlock(so);
334 	}
335 	/*
336 	 * Always set receive timeout to detect server crash and reconnect.
337 	 * Otherwise, we can get stuck in soreceive forever.
338 	 */
339 	mtx_enter(&so->so_rcv.sb_mtx);
340 	so->so_rcv.sb_timeo_nsecs = SEC_TO_NSEC(5);
341 	mtx_leave(&so->so_rcv.sb_mtx);
342 	mtx_enter(&so->so_snd.sb_mtx);
343 	if (nmp->nm_flag & (NFSMNT_SOFT | NFSMNT_INT))
344 		so->so_snd.sb_timeo_nsecs = SEC_TO_NSEC(5);
345 	else
346 		so->so_snd.sb_timeo_nsecs = INFSLP;
347 	mtx_leave(&so->so_snd.sb_mtx);
348 	if (nmp->nm_sotype == SOCK_DGRAM) {
349 		sndreserve = nmp->nm_wsize + NFS_MAXPKTHDR;
350 		rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
351 		    NFS_MAXPKTHDR) * 2;
352 	} else if (nmp->nm_sotype == SOCK_STREAM) {
353 		if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
354 			*mtod(mopt, int32_t *) = 1;
355 			mopt->m_len = sizeof(int32_t);
356 			sosetopt(so, SOL_SOCKET, SO_KEEPALIVE, mopt);
357 		}
358 		if (so->so_proto->pr_protocol == IPPROTO_TCP) {
359 			*mtod(mopt, int32_t *) = 1;
360 			mopt->m_len = sizeof(int32_t);
361 			sosetopt(so, IPPROTO_TCP, TCP_NODELAY, mopt);
362 		}
363 		sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR +
364 		    sizeof (u_int32_t)) * 2;
365 		rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR +
366 		    sizeof (u_int32_t)) * 2;
367 	} else {
368 		panic("%s: nm_sotype %d", __func__, nmp->nm_sotype);
369 	}
370 	solock(so);
371 	error = soreserve(so, sndreserve, rcvreserve);
372 	if (error)
373 		goto bad_locked;
374 	so->so_rcv.sb_flags |= SB_NOINTR;
375 	so->so_snd.sb_flags |= SB_NOINTR;
376 	sounlock(so);
377 
378 	m_freem(mopt);
379 	m_freem(nam);
380 
381 	/* Initialize other non-zero congestion variables */
382 	nfs_init_rtt(nmp);
383 	nmp->nm_cwnd = NFS_MAXCWND / 2;	    /* Initial send window */
384 	nmp->nm_sent = 0;
385 	nmp->nm_timeouts = 0;
386 	return (0);
387 
388 bad_locked:
389 	sounlock(so);
390 bad:
391 
392 	m_freem(mopt);
393 	m_freem(nam);
394 
395 	nfs_disconnect(nmp);
396 	return (error);
397 }
398 
399 /*
400  * Reconnect routine:
401  * Called when a connection is broken on a reliable protocol.
402  * - clean up the old socket
403  * - nfs_connect() again
404  * - set R_MUSTRESEND for all outstanding requests on mount point
405  * If this fails the mount point is DEAD!
406  * nb: Must be called with the nfs_sndlock() set on the mount point.
407  */
408 int
409 nfs_reconnect(struct nfsreq *rep)
410 {
411 	struct nfsreq *rp;
412 	struct nfsmount *nmp = rep->r_nmp;
413 	int error;
414 
415 	nfs_disconnect(nmp);
416 	while ((error = nfs_connect(nmp, rep)) != 0) {
417 		if (error == EINTR || error == ERESTART)
418 			return (EINTR);
419 		tsleep_nsec(&nowake, PSOCK, "nfsrecon", SEC_TO_NSEC(1));
420 	}
421 
422 	/*
423 	 * Loop through outstanding request list and fix up all requests
424 	 * on old socket.
425 	 */
426 	TAILQ_FOREACH(rp, &nmp->nm_reqsq, r_chain) {
427 		rp->r_flags |= R_MUSTRESEND;
428 		rp->r_rexmit = 0;
429 	}
430 	return (0);
431 }
432 
433 /*
434  * NFS disconnect. Clean up and unlink.
435  */
436 void
437 nfs_disconnect(struct nfsmount *nmp)
438 {
439 	struct socket *so;
440 
441 	if (nmp->nm_so) {
442 		so = nmp->nm_so;
443 		nmp->nm_so = NULL;
444 		soshutdown(so, SHUT_RDWR);
445 		soclose(so, 0);
446 	}
447 }
448 
449 /*
450  * This is the nfs send routine. For connection based socket types, it
451  * must be called with an nfs_sndlock() on the socket.
452  * "rep == NULL" indicates that it has been called from a server.
453  * For the client side:
454  * - return EINTR if the RPC is terminated, 0 otherwise
455  * - set R_MUSTRESEND if the send fails for any reason
456  * - do any cleanup required by recoverable socket errors (???)
457  * For the server side:
458  * - return EINTR or ERESTART if interrupted by a signal
459  * - return EPIPE if a connection is lost for connection based sockets (TCP...)
460  * - do any cleanup required by recoverable socket errors (???)
461  */
462 int
463 nfs_send(struct socket *so, struct mbuf *nam, struct mbuf *top,
464     struct nfsreq *rep)
465 {
466 	struct mbuf *sendnam;
467 	int error, soflags, flags;
468 
469 	if (rep) {
470 		if (rep->r_flags & R_SOFTTERM) {
471 			m_freem(top);
472 			return (EINTR);
473 		}
474 		if ((so = rep->r_nmp->nm_so) == NULL) {
475 			rep->r_flags |= R_MUSTRESEND;
476 			m_freem(top);
477 			return (0);
478 		}
479 		rep->r_flags &= ~R_MUSTRESEND;
480 		soflags = rep->r_nmp->nm_soflags;
481 	} else
482 		soflags = so->so_proto->pr_flags;
483 	if ((soflags & PR_CONNREQUIRED) || (so->so_state & SS_ISCONNECTED))
484 		sendnam = NULL;
485 	else
486 		sendnam = nam;
487 	flags = 0;
488 
489 	error = sosend(so, sendnam, NULL, top, NULL, flags);
490 	if (error) {
491 		if (rep) {
492 			/*
493 			 * Deal with errors for the client side.
494 			 */
495 			if (rep->r_flags & R_SOFTTERM)
496 				error = EINTR;
497 			else
498 				rep->r_flags |= R_MUSTRESEND;
499 		}
500 
501 		/*
502 		 * Handle any recoverable (soft) socket errors here. (???)
503 		 */
504 		if (error != EINTR && error != ERESTART &&
505 		    error != EWOULDBLOCK && error != EPIPE)
506 			error = 0;
507 	}
508 	return (error);
509 }
510 
511 #ifdef NFSCLIENT
512 /*
513  * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
514  * done by soreceive(), but for SOCK_STREAM we must deal with the Record
515  * Mark and consolidate the data into a new mbuf list.
516  * nb: Sometimes TCP passes the data up to soreceive() in long lists of
517  *     small mbufs.
518  * For SOCK_STREAM we must be very careful to read an entire record once
519  * we have read any of it, even if the system call has been interrupted.
520  */
521 int
522 nfs_receive(struct nfsreq *rep, struct mbuf **aname, struct mbuf **mp)
523 {
524 	struct socket *so;
525 	struct uio auio;
526 	struct iovec aio;
527 	struct mbuf *m;
528 	struct mbuf *control;
529 	u_int32_t len;
530 	struct mbuf **getnam;
531 	int error, sotype, rcvflg;
532 	struct proc *p = curproc;	/* XXX */
533 
534 	/*
535 	 * Set up arguments for soreceive()
536 	 */
537 	*mp = NULL;
538 	*aname = NULL;
539 	sotype = rep->r_nmp->nm_sotype;
540 
541 	/*
542 	 * For reliable protocols, lock against other senders/receivers
543 	 * in case a reconnect is necessary.
544 	 * For SOCK_STREAM, first get the Record Mark to find out how much
545 	 * more there is to get.
546 	 * We must lock the socket against other receivers
547 	 * until we have an entire rpc request/reply.
548 	 */
549 	if (sotype != SOCK_DGRAM) {
550 		error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
551 		if (error)
552 			return (error);
553 tryagain:
554 		/*
555 		 * Check for fatal errors and resending request.
556 		 */
557 		/*
558 		 * Ugh: If a reconnect attempt just happened, nm_so
559 		 * would have changed. NULL indicates a failed
560 		 * attempt that has essentially shut down this
561 		 * mount point.
562 		 */
563 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
564 			nfs_sndunlock(&rep->r_nmp->nm_flag);
565 			return (EINTR);
566 		}
567 		so = rep->r_nmp->nm_so;
568 		if (!so) {
569 			error = nfs_reconnect(rep);
570 			if (error) {
571 				nfs_sndunlock(&rep->r_nmp->nm_flag);
572 				return (error);
573 			}
574 			goto tryagain;
575 		}
576 		while (rep->r_flags & R_MUSTRESEND) {
577 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
578 			nfsstats.rpcretries++;
579 			rep->r_rtt = 0;
580 			rep->r_flags &= ~R_TIMING;
581 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
582 			if (error) {
583 				if (error == EINTR || error == ERESTART ||
584 				    (error = nfs_reconnect(rep)) != 0) {
585 					nfs_sndunlock(&rep->r_nmp->nm_flag);
586 					return (error);
587 				}
588 				goto tryagain;
589 			}
590 		}
591 		nfs_sndunlock(&rep->r_nmp->nm_flag);
592 		if (sotype == SOCK_STREAM) {
593 			aio.iov_base = (caddr_t) &len;
594 			aio.iov_len = sizeof(u_int32_t);
595 			auio.uio_iov = &aio;
596 			auio.uio_iovcnt = 1;
597 			auio.uio_segflg = UIO_SYSSPACE;
598 			auio.uio_rw = UIO_READ;
599 			auio.uio_offset = 0;
600 			auio.uio_resid = sizeof(u_int32_t);
601 			auio.uio_procp = p;
602 			do {
603 				rcvflg = MSG_WAITALL;
604 				error = soreceive(so, NULL, &auio, NULL, NULL,
605 				    &rcvflg, 0);
606 				if (error == EWOULDBLOCK && rep) {
607 					if (rep->r_flags & R_SOFTTERM)
608 						return (EINTR);
609 					/*
610 					 * looks like the server died after it
611 					 * received the request, make sure
612 					 * that we will retransmit and we
613 					 * don't get stuck here forever.
614 					 */
615 					if (rep->r_rexmit >=
616 					    rep->r_nmp->nm_retry) {
617 						nfsstats.rpctimeouts++;
618 						error = EPIPE;
619 					}
620 				}
621 			} while (error == EWOULDBLOCK);
622 			if (!error && auio.uio_resid > 0) {
623 			    log(LOG_INFO,
624 				 "short receive (%zu/%zu) from nfs server %s\n",
625 				 sizeof(u_int32_t) - auio.uio_resid,
626 				 sizeof(u_int32_t),
627 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
628 			    error = EPIPE;
629 			}
630 			if (error)
631 				goto errout;
632 
633 			len = ntohl(len) & ~0x80000000;
634 			/*
635 			 * This is SERIOUS! We are out of sync with the sender
636 			 * and forcing a disconnect/reconnect is all I can do.
637 			 */
638 			if (len > NFS_MAXPACKET) {
639 			    log(LOG_ERR, "%s (%u) from nfs server %s\n",
640 				"impossible packet length",
641 				len,
642 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
643 			    error = EFBIG;
644 			    goto errout;
645 			}
646 			auio.uio_resid = len;
647 			do {
648 			    rcvflg = MSG_WAITALL;
649 			    error =  soreceive(so, NULL, &auio, mp, NULL,
650 			        &rcvflg, 0);
651 			} while (error == EWOULDBLOCK || error == EINTR ||
652 			    error == ERESTART);
653 			if (!error && auio.uio_resid > 0) {
654 				log(LOG_INFO, "short receive (%zu/%u) from "
655 				    "nfs server %s\n", len - auio.uio_resid,
656 				    len, rep->r_nmp->nm_mountp->
657 				    mnt_stat.f_mntfromname);
658 				error = EPIPE;
659 			}
660 		} else {
661 			/*
662 			 * NB: Since uio_resid is big, MSG_WAITALL is ignored
663 			 * and soreceive() will return when it has either a
664 			 * control msg or a data msg.
665 			 * We have no use for control msg., but must grab them
666 			 * and then throw them away so we know what is going
667 			 * on.
668 			 */
669 			auio.uio_resid = len = 100000000; /* Anything Big */
670 			auio.uio_procp = p;
671 			do {
672 				rcvflg = 0;
673 				error = soreceive(so, NULL, &auio, mp, &control,
674 				    &rcvflg, 0);
675 				m_freem(control);
676 				if (error == EWOULDBLOCK && rep) {
677 					if (rep->r_flags & R_SOFTTERM)
678 						return (EINTR);
679 				}
680 			} while (error == EWOULDBLOCK ||
681 			    (!error && *mp == NULL && control));
682 			if ((rcvflg & MSG_EOR) == 0)
683 				printf("Egad!!\n");
684 			if (!error && *mp == NULL)
685 				error = EPIPE;
686 			len -= auio.uio_resid;
687 		}
688 errout:
689 		if (error && error != EINTR && error != ERESTART) {
690 			m_freemp(mp);
691 			if (error != EPIPE)
692 				log(LOG_INFO,
693 				    "receive error %d from nfs server %s\n",
694 				    error,
695 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
696 			error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
697 			if (!error) {
698 				error = nfs_reconnect(rep);
699 				if (!error)
700 					goto tryagain;
701 				nfs_sndunlock(&rep->r_nmp->nm_flag);
702 			}
703 		}
704 	} else {
705 		if ((so = rep->r_nmp->nm_so) == NULL)
706 			return (EACCES);
707 		if (so->so_state & SS_ISCONNECTED)
708 			getnam = NULL;
709 		else
710 			getnam = aname;
711 		auio.uio_resid = len = 1000000;
712 		auio.uio_procp = p;
713 		do {
714 			rcvflg = 0;
715 			error = soreceive(so, getnam, &auio, mp, NULL,
716 			    &rcvflg, 0);
717 			if (error == EWOULDBLOCK &&
718 			    (rep->r_flags & R_SOFTTERM))
719 				return (EINTR);
720 		} while (error == EWOULDBLOCK);
721 		len -= auio.uio_resid;
722 	}
723 	if (error)
724 		m_freemp(mp);
725 	/*
726 	 * Search for any mbufs that are not a multiple of 4 bytes long
727 	 * or with m_data not longword aligned.
728 	 * These could cause pointer alignment problems, so copy them to
729 	 * well aligned mbufs.
730 	 */
731 	nfs_realign(mp, 5 * NFSX_UNSIGNED);
732 	return (error);
733 }
734 
735 /*
736  * Implement receipt of reply on a socket.
737  * We must search through the list of received datagrams matching them
738  * with outstanding requests using the xid, until ours is found.
739  */
740 int
741 nfs_reply(struct nfsreq *myrep)
742 {
743 	struct nfsreq *rep;
744 	struct nfsmount *nmp = myrep->r_nmp;
745 	struct nfsm_info	info;
746 	struct mbuf *nam;
747 	u_int32_t rxid, *tl, t1;
748 	caddr_t cp2;
749 	int error;
750 
751 	/*
752 	 * Loop around until we get our own reply
753 	 */
754 	for (;;) {
755 		/*
756 		 * Lock against other receivers so that I don't get stuck in
757 		 * sbwait() after someone else has received my reply for me.
758 		 * Also necessary for connection based protocols to avoid
759 		 * race conditions during a reconnect.
760 		 */
761 		error = nfs_rcvlock(myrep);
762 		if (error)
763 			return (error == EALREADY ? 0 : error);
764 
765 		/*
766 		 * Get the next Rpc reply off the socket
767 		 */
768 		error = nfs_receive(myrep, &nam, &info.nmi_mrep);
769 		nfs_rcvunlock(&nmp->nm_flag);
770 		if (error) {
771 
772 			/*
773 			 * Ignore routing errors on connectionless protocols??
774 			 */
775 			if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
776 				if (nmp->nm_so)
777 					nmp->nm_so->so_error = 0;
778 				continue;
779 			}
780 			return (error);
781 		}
782 		m_freem(nam);
783 
784 		/*
785 		 * Get the xid and check that it is an rpc reply
786 		 */
787 		info.nmi_md = info.nmi_mrep;
788 		info.nmi_dpos = mtod(info.nmi_md, caddr_t);
789 		nfsm_dissect(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
790 		rxid = *tl++;
791 		if (*tl != rpc_reply) {
792 			nfsstats.rpcinvalid++;
793 			m_freem(info.nmi_mrep);
794 nfsmout:
795 			continue;
796 		}
797 
798 		/*
799 		 * Loop through the request list to match up the reply
800 		 * Iff no match, just drop the datagram
801 		 */
802 		TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
803 			if (rep->r_mrep == NULL && rxid == rep->r_xid) {
804 				/* Found it.. */
805 				rep->r_mrep = info.nmi_mrep;
806 				rep->r_md = info.nmi_md;
807 				rep->r_dpos = info.nmi_dpos;
808 
809 				/*
810 				 * Update congestion window.
811 				 * Do the additive increase of
812 				 * one rpc/rtt.
813 				 */
814 				if (nmp->nm_cwnd <= nmp->nm_sent) {
815 					nmp->nm_cwnd +=
816 					   (NFS_CWNDSCALE * NFS_CWNDSCALE +
817 					   (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
818 					if (nmp->nm_cwnd > NFS_MAXCWND)
819 						nmp->nm_cwnd = NFS_MAXCWND;
820 				}
821 				rep->r_flags &= ~R_SENT;
822 				nmp->nm_sent -= NFS_CWNDSCALE;
823 
824 				if (rep->r_flags & R_TIMING)
825 					nfs_update_rtt(rep);
826 
827 				nmp->nm_timeouts = 0;
828 				break;
829 			}
830 		}
831 		/*
832 		 * If not matched to a request, drop it.
833 		 * If it's mine, get out.
834 		 */
835 		if (rep == 0) {
836 			nfsstats.rpcunexpected++;
837 			m_freem(info.nmi_mrep);
838 		} else if (rep == myrep) {
839 			if (rep->r_mrep == NULL)
840 				panic("nfsreply nil");
841 			return (0);
842 		}
843 	}
844 }
845 
846 /*
847  * nfs_request - goes something like this
848  *	- fill in request struct
849  *	- links it into list
850  *	- calls nfs_send() for first transmit
851  *	- calls nfs_receive() to get reply
852  *	- break down rpc header and return with nfs reply pointed to
853  *	  by mrep or error
854  * nb: always frees up mreq mbuf list
855  */
856 int
857 nfs_request(struct vnode *vp, int procnum, struct nfsm_info *infop)
858 {
859 	struct mbuf *m;
860 	u_int32_t *tl;
861 	struct nfsmount *nmp;
862 	caddr_t cp2;
863 	int t1, i, error = 0;
864 	int trylater_delay;
865 	struct nfsreq *rep;
866 	struct nfsm_info info;
867 
868 	rep = pool_get(&nfsreqpl, PR_WAITOK);
869 	rep->r_nmp = VFSTONFS(vp->v_mount);
870 	rep->r_vp = vp;
871 	rep->r_procp = infop->nmi_procp;
872 	rep->r_procnum = procnum;
873 
874 	/* empty mbuf for AUTH_UNIX header */
875 	rep->r_mreq = m_gethdr(M_WAIT, MT_DATA);
876 	rep->r_mreq->m_next = infop->nmi_mreq;
877 	rep->r_mreq->m_len = 0;
878 	m_calchdrlen(rep->r_mreq);
879 
880 	trylater_delay = NFS_MINTIMEO;
881 
882 	nmp = rep->r_nmp;
883 
884 	/* Get the RPC header with authorization. */
885 	nfsm_rpchead(rep, infop->nmi_cred, RPCAUTH_UNIX);
886 	m = rep->r_mreq;
887 
888 	/*
889 	 * For stream protocols, insert a Sun RPC Record Mark.
890 	 */
891 	if (nmp->nm_sotype == SOCK_STREAM) {
892 		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
893 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
894 		    (m->m_pkthdr.len - NFSX_UNSIGNED));
895 	}
896 
897 tryagain:
898 	rep->r_rtt = rep->r_rexmit = 0;
899 	if (nfs_ptimers[rep->r_procnum] != NFS_DEFAULT_TIMER)
900 		rep->r_flags = R_TIMING;
901 	else
902 		rep->r_flags = 0;
903 	rep->r_mrep = NULL;
904 
905 	/*
906 	 * Do the client side RPC.
907 	 */
908 	nfsstats.rpcrequests++;
909 	/*
910 	 * Chain request into list of outstanding requests. Be sure
911 	 * to put it LAST so timer finds oldest requests first.
912 	 */
913 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
914 		timeout_add(&nmp->nm_rtimeout, nfs_ticks);
915 	TAILQ_INSERT_TAIL(&nmp->nm_reqsq, rep, r_chain);
916 
917 	/*
918 	 * If backing off another request or avoiding congestion, don't
919 	 * send this one now but let timer do it. If not timing a request,
920 	 * do it now.
921 	 */
922 	if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
923 		(nmp->nm_flag & NFSMNT_DUMBTIMR) ||
924 		nmp->nm_sent < nmp->nm_cwnd)) {
925 		if (nmp->nm_soflags & PR_CONNREQUIRED)
926 			error = nfs_sndlock(&nmp->nm_flag, rep);
927 		if (!error) {
928 			error = nfs_send(nmp->nm_so, nmp->nm_nam,
929 			    m_copym(m, 0, M_COPYALL, M_WAIT), rep);
930 			if (nmp->nm_soflags & PR_CONNREQUIRED)
931 				nfs_sndunlock(&nmp->nm_flag);
932 		}
933 		if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
934 			nmp->nm_sent += NFS_CWNDSCALE;
935 			rep->r_flags |= R_SENT;
936 		}
937 	} else {
938 		rep->r_rtt = -1;
939 	}
940 
941 	/*
942 	 * Wait for the reply from our send or the timer's.
943 	 */
944 	if (!error || error == EPIPE)
945 		error = nfs_reply(rep);
946 
947 	/*
948 	 * RPC done, unlink the request.
949 	 */
950 	TAILQ_REMOVE(&nmp->nm_reqsq, rep, r_chain);
951 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
952 		timeout_del(&nmp->nm_rtimeout);
953 
954 	/*
955 	 * Decrement the outstanding request count.
956 	 */
957 	if (rep->r_flags & R_SENT) {
958 		rep->r_flags &= ~R_SENT;	/* paranoia */
959 		nmp->nm_sent -= NFS_CWNDSCALE;
960 	}
961 
962 	/*
963 	 * If there was a successful reply and a tprintf msg.
964 	 * tprintf a response.
965 	 */
966 	if (!error && (rep->r_flags & R_TPRINTFMSG))
967 		nfs_msg(rep, "is alive again");
968 	info.nmi_mrep = rep->r_mrep;
969 	info.nmi_md = rep->r_md;
970 	info.nmi_dpos = rep->r_dpos;
971 	if (error) {
972 		infop->nmi_mrep = NULL;
973 		goto nfsmout1;
974 	}
975 
976 	/*
977 	 * break down the rpc header and check if ok
978 	 */
979 	nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
980 	if (*tl++ == rpc_msgdenied) {
981 		if (*tl == rpc_mismatch)
982 			error = EOPNOTSUPP;
983 		else
984 			error = EACCES;	/* Should be EAUTH. */
985 		infop->nmi_mrep = NULL;
986 		goto nfsmout1;
987 	}
988 
989 	/*
990 	 * Since we only support RPCAUTH_UNIX atm we step over the
991 	 * reply verifer type, and in the (error) case that there really
992 	 * is any data in it, we advance over it.
993 	 */
994 	tl++;			/* Step over verifer type */
995 	i = fxdr_unsigned(int32_t, *tl);
996 	if (i > 0)
997 		nfsm_adv(nfsm_rndup(i));	/* Should not happen */
998 
999 	nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
1000 	/* 0 == ok */
1001 	if (*tl == 0) {
1002 		nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
1003 		if (*tl != 0) {
1004 			error = fxdr_unsigned(int, *tl);
1005 			if ((nmp->nm_flag & NFSMNT_NFSV3) &&
1006 			    error == NFSERR_TRYLATER) {
1007 				m_freem(info.nmi_mrep);
1008 				error = 0;
1009 				tsleep_nsec(&nowake, PSOCK, "nfsretry",
1010 				    SEC_TO_NSEC(trylater_delay));
1011 				trylater_delay *= NFS_TIMEOUTMUL;
1012 				if (trylater_delay > NFS_MAXTIMEO)
1013 					trylater_delay = NFS_MAXTIMEO;
1014 
1015 				goto tryagain;
1016 			}
1017 
1018 			/*
1019 			 * If the File Handle was stale, invalidate the
1020 			 * lookup cache, just in case.
1021 			 */
1022 			if (error == ESTALE)
1023 				cache_purge(rep->r_vp);
1024 		}
1025 		goto nfsmout;
1026 	}
1027 
1028 	error = EPROTONOSUPPORT;
1029 
1030 nfsmout:
1031 	infop->nmi_mrep = info.nmi_mrep;
1032 	infop->nmi_md = info.nmi_md;
1033 	infop->nmi_dpos = info.nmi_dpos;
1034 nfsmout1:
1035 	m_freem(rep->r_mreq);
1036 	pool_put(&nfsreqpl, rep);
1037 	return (error);
1038 }
1039 #endif /* NFSCLIENT */
1040 
1041 /*
1042  * Generate the rpc reply header
1043  * siz arg. is used to decide if adding a cluster is worthwhile
1044  */
1045 int
1046 nfs_rephead(int siz, struct nfsrv_descript *nd, struct nfssvc_sock *slp,
1047     int err, struct mbuf **mrq, struct mbuf **mbp)
1048 {
1049 	u_int32_t *tl;
1050 	struct mbuf *mreq;
1051 	struct mbuf *mb;
1052 
1053 	MGETHDR(mreq, M_WAIT, MT_DATA);
1054 	mb = mreq;
1055 	/*
1056 	 * If this is a big reply, use a cluster else
1057 	 * try and leave leading space for the lower level headers.
1058 	 */
1059 	siz += RPC_REPLYSIZ;
1060 	if (siz >= MHLEN - max_hdr) {
1061 		MCLGET(mreq, M_WAIT);
1062 	} else
1063 		mreq->m_data += max_hdr;
1064 	tl = mtod(mreq, u_int32_t *);
1065 	mreq->m_len = 6 * NFSX_UNSIGNED;
1066 	*tl++ = txdr_unsigned(nd->nd_retxid);
1067 	*tl++ = rpc_reply;
1068 	if (err == ERPCMISMATCH || (err & NFSERR_AUTHERR)) {
1069 		*tl++ = rpc_msgdenied;
1070 		if (err & NFSERR_AUTHERR) {
1071 			*tl++ = rpc_autherr;
1072 			*tl = txdr_unsigned(err & ~NFSERR_AUTHERR);
1073 			mreq->m_len -= NFSX_UNSIGNED;
1074 		} else {
1075 			*tl++ = rpc_mismatch;
1076 			*tl++ = txdr_unsigned(RPC_VER2);
1077 			*tl = txdr_unsigned(RPC_VER2);
1078 		}
1079 	} else {
1080 		*tl++ = rpc_msgaccepted;
1081 
1082 		/* AUTH_UNIX requires RPCAUTH_NULL. */
1083 		*tl++ = 0;
1084 		*tl++ = 0;
1085 
1086 		switch (err) {
1087 		case EPROGUNAVAIL:
1088 			*tl = txdr_unsigned(RPC_PROGUNAVAIL);
1089 			break;
1090 		case EPROGMISMATCH:
1091 			*tl = txdr_unsigned(RPC_PROGMISMATCH);
1092 			tl = nfsm_build(&mb, 2 * NFSX_UNSIGNED);
1093 			*tl++ = txdr_unsigned(NFS_VER2);
1094 			*tl = txdr_unsigned(NFS_VER3);
1095 			break;
1096 		case EPROCUNAVAIL:
1097 			*tl = txdr_unsigned(RPC_PROCUNAVAIL);
1098 			break;
1099 		case EBADRPC:
1100 			*tl = txdr_unsigned(RPC_GARBAGE);
1101 			break;
1102 		default:
1103 			*tl = 0;
1104 			if (err != NFSERR_RETVOID) {
1105 				tl = nfsm_build(&mb, NFSX_UNSIGNED);
1106 				if (err)
1107 				    *tl = txdr_unsigned(nfsrv_errmap(nd, err));
1108 				else
1109 				    *tl = 0;
1110 			}
1111 			break;
1112 		};
1113 	}
1114 
1115 	*mrq = mreq;
1116 	if (mbp != NULL)
1117 		*mbp = mb;
1118 	if (err != 0 && err != NFSERR_RETVOID)
1119 		nfsstats.srvrpc_errs++;
1120 	return (0);
1121 }
1122 
1123 /*
1124  * nfs timer routine
1125  * Scan the nfsreq list and retransmit any requests that have timed out.
1126  */
1127 void
1128 nfs_timer(void *arg)
1129 {
1130 	struct nfsmount *nmp = arg;
1131 	struct nfsreq *rep;
1132 	struct mbuf *m;
1133 	struct socket *so;
1134 	int timeo, error;
1135 
1136 	NET_LOCK();
1137 	TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
1138 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
1139 			continue;
1140 		if (nfs_sigintr(nmp, rep, rep->r_procp)) {
1141 			rep->r_flags |= R_SOFTTERM;
1142 			continue;
1143 		}
1144 		if (rep->r_rtt >= 0) {
1145 			rep->r_rtt++;
1146 			if (nmp->nm_flag & NFSMNT_DUMBTIMR)
1147 				timeo = nmp->nm_timeo;
1148 			else
1149 				timeo = nfs_estimate_rto(nmp, rep->r_procnum);
1150 			if (nmp->nm_timeouts > 0)
1151 				timeo *= nfs_backoff[nmp->nm_timeouts - 1];
1152 			if (rep->r_rtt <= timeo)
1153 				continue;
1154 			if (nmp->nm_timeouts < nitems(nfs_backoff))
1155 				nmp->nm_timeouts++;
1156 		}
1157 
1158 		/* Check for server not responding. */
1159 		if ((rep->r_flags & R_TPRINTFMSG) == 0 && rep->r_rexmit > 4) {
1160 			nfs_msg(rep, "not responding");
1161 			rep->r_flags |= R_TPRINTFMSG;
1162 		}
1163 		if (rep->r_rexmit >= nmp->nm_retry) {	/* too many */
1164 			nfsstats.rpctimeouts++;
1165 			rep->r_flags |= R_SOFTTERM;
1166 			continue;
1167 		}
1168 		if (nmp->nm_sotype != SOCK_DGRAM) {
1169 			if (++rep->r_rexmit > NFS_MAXREXMIT)
1170 				rep->r_rexmit = NFS_MAXREXMIT;
1171 			continue;
1172 		}
1173 
1174 		if ((so = nmp->nm_so) == NULL)
1175 			continue;
1176 
1177 		/*
1178 		 * If there is enough space and the window allows..
1179 		 *	Resend it
1180 		 * Set r_rtt to -1 in case we fail to send it now.
1181 		 */
1182 		rep->r_rtt = -1;
1183 		if (sbspace(so, &so->so_snd) >= rep->r_mreq->m_pkthdr.len &&
1184 		   ((nmp->nm_flag & NFSMNT_DUMBTIMR) ||
1185 		    (rep->r_flags & R_SENT) ||
1186 		    nmp->nm_sent < nmp->nm_cwnd) &&
1187 		   (m = m_copym(rep->r_mreq, 0, M_COPYALL, M_DONTWAIT))){
1188 			if ((nmp->nm_flag & NFSMNT_NOCONN) == 0)
1189 				error = pru_send(so, m, NULL, NULL);
1190 			else
1191 				error = pru_send(so, m, nmp->nm_nam, NULL);
1192 			if (error) {
1193 				if (NFSIGNORE_SOERROR(nmp->nm_soflags, error))
1194 					so->so_error = 0;
1195 			} else {
1196 				/*
1197 				 * Iff first send, start timing
1198 				 * else turn timing off, backoff timer
1199 				 * and divide congestion window by 2.
1200 				 */
1201 				if (rep->r_flags & R_SENT) {
1202 					rep->r_flags &= ~R_TIMING;
1203 					if (++rep->r_rexmit > NFS_MAXREXMIT)
1204 						rep->r_rexmit = NFS_MAXREXMIT;
1205 					nmp->nm_cwnd >>= 1;
1206 					if (nmp->nm_cwnd < NFS_CWNDSCALE)
1207 						nmp->nm_cwnd = NFS_CWNDSCALE;
1208 					nfsstats.rpcretries++;
1209 				} else {
1210 					rep->r_flags |= R_SENT;
1211 					nmp->nm_sent += NFS_CWNDSCALE;
1212 				}
1213 				rep->r_rtt = 0;
1214 			}
1215 		}
1216 	}
1217 	NET_UNLOCK();
1218 	timeout_add(&nmp->nm_rtimeout, nfs_ticks);
1219 }
1220 
1221 /*
1222  * Test for a termination condition pending on the process.
1223  * This is used for NFSMNT_INT mounts.
1224  */
1225 int
1226 nfs_sigintr(struct nfsmount *nmp, struct nfsreq *rep, struct proc *p)
1227 {
1228 
1229 	if (rep && (rep->r_flags & R_SOFTTERM))
1230 		return (EINTR);
1231 	if (!(nmp->nm_flag & NFSMNT_INT))
1232 		return (0);
1233 	if (p && (SIGPENDING(p) & ~p->p_p->ps_sigacts->ps_sigignore &
1234 	    NFSINT_SIGMASK))
1235 		return (EINTR);
1236 	return (0);
1237 }
1238 
1239 /*
1240  * Lock a socket against others.
1241  * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
1242  * and also to avoid race conditions between the processes with nfs requests
1243  * in progress when a reconnect is necessary.
1244  */
1245 int
1246 nfs_sndlock(int *flagp, struct nfsreq *rep)
1247 {
1248 	uint64_t slptimeo = INFSLP;
1249 	struct proc *p;
1250 	int slpflag = 0;
1251 
1252 	if (rep) {
1253 		p = rep->r_procp;
1254 		if (rep->r_nmp->nm_flag & NFSMNT_INT)
1255 			slpflag = PCATCH;
1256 	} else
1257 		p = NULL;
1258 	while (*flagp & NFSMNT_SNDLOCK) {
1259 		if (rep && nfs_sigintr(rep->r_nmp, rep, p))
1260 			return (EINTR);
1261 		*flagp |= NFSMNT_WANTSND;
1262 		tsleep_nsec(flagp, slpflag | (PZERO - 1), "nfsndlck", slptimeo);
1263 		if (slpflag == PCATCH) {
1264 			slpflag = 0;
1265 			slptimeo = SEC_TO_NSEC(2);
1266 		}
1267 	}
1268 	*flagp |= NFSMNT_SNDLOCK;
1269 	return (0);
1270 }
1271 
1272 /*
1273  * Unlock the stream socket for others.
1274  */
1275 void
1276 nfs_sndunlock(int *flagp)
1277 {
1278 
1279 	if ((*flagp & NFSMNT_SNDLOCK) == 0)
1280 		panic("nfs sndunlock");
1281 	*flagp &= ~NFSMNT_SNDLOCK;
1282 	if (*flagp & NFSMNT_WANTSND) {
1283 		*flagp &= ~NFSMNT_WANTSND;
1284 		wakeup((caddr_t)flagp);
1285 	}
1286 }
1287 
1288 int
1289 nfs_rcvlock(struct nfsreq *rep)
1290 {
1291 	uint64_t slptimeo = INFSLP;
1292 	int *flagp = &rep->r_nmp->nm_flag;
1293 	int slpflag;
1294 
1295 	if (*flagp & NFSMNT_INT)
1296 		slpflag = PCATCH;
1297 	else
1298 		slpflag = 0;
1299 
1300 	while (*flagp & NFSMNT_RCVLOCK) {
1301 		if (nfs_sigintr(rep->r_nmp, rep, rep->r_procp))
1302 			return (EINTR);
1303 		*flagp |= NFSMNT_WANTRCV;
1304 		tsleep_nsec(flagp, slpflag | (PZERO - 1), "nfsrcvlk", slptimeo);
1305 		if (rep->r_mrep != NULL) {
1306 			/*
1307 			 * Don't take the lock if our reply has been received
1308 			 * while we where sleeping.
1309 			 */
1310 			 return (EALREADY);
1311 		}
1312 		if (slpflag == PCATCH) {
1313 			slpflag = 0;
1314 			slptimeo = SEC_TO_NSEC(2);
1315 		}
1316 	}
1317 	*flagp |= NFSMNT_RCVLOCK;
1318 	return (0);
1319 }
1320 
1321 /*
1322  * Unlock the stream socket for others.
1323  */
1324 void
1325 nfs_rcvunlock(int *flagp)
1326 {
1327 
1328 	if ((*flagp & NFSMNT_RCVLOCK) == 0)
1329 		panic("nfs rcvunlock");
1330 	*flagp &= ~NFSMNT_RCVLOCK;
1331 	if (*flagp & NFSMNT_WANTRCV) {
1332 		*flagp &= ~NFSMNT_WANTRCV;
1333 		wakeup(flagp);
1334 	}
1335 }
1336 
1337 /*
1338  * Auxiliary routine to align the length of mbuf copies made with m_copyback().
1339  */
1340 void
1341 nfs_realign_fixup(struct mbuf *m, struct mbuf *n, unsigned int *off)
1342 {
1343 	size_t padding;
1344 
1345 	/*
1346 	 * The maximum number of bytes that m_copyback() places in a mbuf is
1347 	 * always an aligned quantity, so realign happens at the chain's tail.
1348 	 */
1349 	while (n->m_next != NULL)
1350 		n = n->m_next;
1351 
1352 	/*
1353 	 * Pad from the next elements in the source chain. Loop until the
1354 	 * destination chain is aligned, or the end of the source is reached.
1355 	 */
1356 	do {
1357 		m = m->m_next;
1358 		if (m == NULL)
1359 			return;
1360 
1361 		padding = min(ALIGN(n->m_len) - n->m_len, m->m_len);
1362 		if (padding > m_trailingspace(n))
1363 			panic("nfs_realign_fixup: no memory to pad to");
1364 
1365 		bcopy(mtod(m, void *), mtod(n, char *) + n->m_len, padding);
1366 
1367 		n->m_len += padding;
1368 		m_adj(m, padding);
1369 		*off += padding;
1370 
1371 	} while (!ALIGNED_POINTER(n->m_len, void *));
1372 }
1373 
1374 /*
1375  * The NFS RPC parsing code uses the data address and the length of mbuf
1376  * structures to calculate on-memory addresses. This function makes sure these
1377  * parameters are correctly aligned.
1378  */
1379 void
1380 nfs_realign(struct mbuf **pm, int hsiz)
1381 {
1382 	struct mbuf *m;
1383 	struct mbuf *n = NULL;
1384 	unsigned int off = 0;
1385 
1386 	++nfs_realign_test;
1387 	while ((m = *pm) != NULL) {
1388 		if (!ALIGNED_POINTER(m->m_data, void *) ||
1389 		    !ALIGNED_POINTER(m->m_len,  void *)) {
1390 			MGET(n, M_WAIT, MT_DATA);
1391 #define ALIGN_POINTER(n) ((u_int)(((n) + sizeof(void *)) & ~sizeof(void *)))
1392 			if (ALIGN_POINTER(m->m_len) >= MINCLSIZE) {
1393 				MCLGET(n, M_WAIT);
1394 			}
1395 			n->m_len = 0;
1396 			break;
1397 		}
1398 		pm = &m->m_next;
1399 	}
1400 	/*
1401 	 * If n is non-NULL, loop on m copying data, then replace the
1402 	 * portion of the chain that had to be realigned.
1403 	 */
1404 	if (n != NULL) {
1405 		++nfs_realign_count;
1406 		while (m) {
1407 			m_copyback(n, off, m->m_len, mtod(m, caddr_t), M_WAIT);
1408 
1409 			/*
1410 			 * If an unaligned amount of memory was copied, fix up
1411 			 * the last mbuf created by m_copyback().
1412 			 */
1413 			if (!ALIGNED_POINTER(m->m_len, void *))
1414 				nfs_realign_fixup(m, n, &off);
1415 
1416 			off += m->m_len;
1417 			m = m->m_next;
1418 		}
1419 		m_freemp(pm);
1420 		*pm = n;
1421 	}
1422 }
1423 
1424 
1425 /*
1426  * Parse an RPC request
1427  * - verify it
1428  * - fill in the cred struct.
1429  */
1430 int
1431 nfs_getreq(struct nfsrv_descript *nd, struct nfsd *nfsd, int has_header)
1432 {
1433 	int len, i;
1434 	u_int32_t *tl;
1435 	int32_t t1;
1436 	caddr_t cp2;
1437 	u_int32_t nfsvers, auth_type;
1438 	int error = 0;
1439 	struct nfsm_info info;
1440 
1441 	info.nmi_mrep = nd->nd_mrep;
1442 	info.nmi_md = nd->nd_md;
1443 	info.nmi_dpos = nd->nd_dpos;
1444 	if (has_header) {
1445 		nfsm_dissect(tl, u_int32_t *, 10 * NFSX_UNSIGNED);
1446 		nd->nd_retxid = fxdr_unsigned(u_int32_t, *tl++);
1447 		if (*tl++ != rpc_call) {
1448 			m_freem(info.nmi_mrep);
1449 			return (EBADRPC);
1450 		}
1451 	} else
1452 		nfsm_dissect(tl, u_int32_t *, 8 * NFSX_UNSIGNED);
1453 	nd->nd_repstat = 0;
1454 	nd->nd_flag = 0;
1455 	if (*tl++ != rpc_vers) {
1456 		nd->nd_repstat = ERPCMISMATCH;
1457 		nd->nd_procnum = NFSPROC_NOOP;
1458 		return (0);
1459 	}
1460 	if (*tl != nfs_prog) {
1461 		nd->nd_repstat = EPROGUNAVAIL;
1462 		nd->nd_procnum = NFSPROC_NOOP;
1463 		return (0);
1464 	}
1465 	tl++;
1466 	nfsvers = fxdr_unsigned(u_int32_t, *tl++);
1467 	if (nfsvers != NFS_VER2 && nfsvers != NFS_VER3) {
1468 		nd->nd_repstat = EPROGMISMATCH;
1469 		nd->nd_procnum = NFSPROC_NOOP;
1470 		return (0);
1471 	}
1472 	if (nfsvers == NFS_VER3)
1473 		nd->nd_flag = ND_NFSV3;
1474 	nd->nd_procnum = fxdr_unsigned(u_int32_t, *tl++);
1475 	if (nd->nd_procnum == NFSPROC_NULL)
1476 		return (0);
1477 	if (nd->nd_procnum >= NFS_NPROCS ||
1478 		(nd->nd_procnum > NFSPROC_COMMIT) ||
1479 		(!nd->nd_flag && nd->nd_procnum > NFSV2PROC_STATFS)) {
1480 		nd->nd_repstat = EPROCUNAVAIL;
1481 		nd->nd_procnum = NFSPROC_NOOP;
1482 		return (0);
1483 	}
1484 	if ((nd->nd_flag & ND_NFSV3) == 0)
1485 		nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
1486 	auth_type = *tl++;
1487 	len = fxdr_unsigned(int, *tl++);
1488 	if (len < 0 || len > RPCAUTH_MAXSIZ) {
1489 		m_freem(info.nmi_mrep);
1490 		return (EBADRPC);
1491 	}
1492 
1493 	/* Handle auth_unix */
1494 	if (auth_type == rpc_auth_unix) {
1495 		len = fxdr_unsigned(int, *++tl);
1496 		if (len < 0 || len > NFS_MAXNAMLEN) {
1497 			m_freem(info.nmi_mrep);
1498 			return (EBADRPC);
1499 		}
1500 		nfsm_adv(nfsm_rndup(len));
1501 		nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
1502 		memset(&nd->nd_cr, 0, sizeof (struct ucred));
1503 		refcnt_init(&nd->nd_cr.cr_refcnt);
1504 		nd->nd_cr.cr_uid = fxdr_unsigned(uid_t, *tl++);
1505 		nd->nd_cr.cr_gid = fxdr_unsigned(gid_t, *tl++);
1506 		len = fxdr_unsigned(int, *tl);
1507 		if (len < 0 || len > RPCAUTH_UNIXGIDS) {
1508 			m_freem(info.nmi_mrep);
1509 			return (EBADRPC);
1510 		}
1511 		nfsm_dissect(tl, u_int32_t *, (len + 2) * NFSX_UNSIGNED);
1512 		for (i = 0; i < len; i++) {
1513 			if (i < NGROUPS_MAX)
1514 				nd->nd_cr.cr_groups[i] =
1515 				    fxdr_unsigned(gid_t, *tl++);
1516 			else
1517 				tl++;
1518 		}
1519 		nd->nd_cr.cr_ngroups = (len > NGROUPS_MAX) ? NGROUPS_MAX : len;
1520 		len = fxdr_unsigned(int, *++tl);
1521 		if (len < 0 || len > RPCAUTH_MAXSIZ) {
1522 			m_freem(info.nmi_mrep);
1523 			return (EBADRPC);
1524 		}
1525 		if (len > 0)
1526 			nfsm_adv(nfsm_rndup(len));
1527 	} else {
1528 		nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
1529 		nd->nd_procnum = NFSPROC_NOOP;
1530 		return (0);
1531 	}
1532 
1533 	nd->nd_md = info.nmi_md;
1534 	nd->nd_dpos = info.nmi_dpos;
1535 	return (0);
1536 nfsmout:
1537 	return (error);
1538 }
1539 
1540 void
1541 nfs_msg(struct nfsreq *rep, char *msg)
1542 {
1543 	tpr_t tpr;
1544 
1545 	if (rep->r_procp)
1546 		tpr = tprintf_open(rep->r_procp);
1547 	else
1548 		tpr = NULL;
1549 
1550 	tprintf(tpr, "nfs server %s: %s\n",
1551 	    rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname, msg);
1552 	tprintf_close(tpr);
1553 }
1554 
1555 #ifdef NFSSERVER
1556 /*
1557  * Socket upcall routine for the nfsd sockets.
1558  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
1559  * Essentially do as much as possible non-blocking, else punt and it will
1560  * be called with M_WAIT from an nfsd.
1561  */
1562 void
1563 nfsrv_rcv(struct socket *so, caddr_t arg, int waitflag)
1564 {
1565 	struct nfssvc_sock *slp = (struct nfssvc_sock *)arg;
1566 	struct mbuf *m;
1567 	struct mbuf *mp, *nam;
1568 	struct uio auio;
1569 	int flags, error;
1570 
1571 	KERNEL_LOCK();
1572 
1573 	if ((slp->ns_flag & SLP_VALID) == 0)
1574 		goto out;
1575 
1576 	/* Defer soreceive() to an nfsd. */
1577 	if (waitflag == M_DONTWAIT) {
1578 		slp->ns_flag |= SLP_NEEDQ;
1579 		goto dorecs;
1580 	}
1581 
1582 	auio.uio_procp = NULL;
1583 	if (so->so_type == SOCK_STREAM) {
1584 		/*
1585 		 * Do soreceive().
1586 		 */
1587 		auio.uio_resid = 1000000000;
1588 		flags = MSG_DONTWAIT;
1589 		error = soreceive(so, &nam, &auio, &mp, NULL,
1590 		    &flags, 0);
1591 		if (error || mp == NULL) {
1592 			if (error == EWOULDBLOCK)
1593 				slp->ns_flag |= SLP_NEEDQ;
1594 			else
1595 				slp->ns_flag |= SLP_DISCONN;
1596 			goto dorecs;
1597 		}
1598 		m = mp;
1599 		if (slp->ns_rawend) {
1600 			slp->ns_rawend->m_next = m;
1601 			slp->ns_cc += 1000000000 - auio.uio_resid;
1602 		} else {
1603 			slp->ns_raw = m;
1604 			slp->ns_cc = 1000000000 - auio.uio_resid;
1605 		}
1606 		while (m->m_next)
1607 			m = m->m_next;
1608 		slp->ns_rawend = m;
1609 
1610 		/*
1611 		 * Now try and parse record(s) out of the raw stream data.
1612 		 */
1613 		error = nfsrv_getstream(slp, waitflag);
1614 		if (error) {
1615 			if (error == EPERM)
1616 				slp->ns_flag |= SLP_DISCONN;
1617 			else
1618 				slp->ns_flag |= SLP_NEEDQ;
1619 		}
1620 	} else {
1621 		do {
1622 			auio.uio_resid = 1000000000;
1623 			flags = MSG_DONTWAIT;
1624 			error = soreceive(so, &nam, &auio, &mp,
1625 			    NULL, &flags, 0);
1626 			if (mp) {
1627 				struct sockaddr_in *sin;
1628 
1629 				if (nam == NULL) {
1630 					nfsstats.srv_errs++;
1631 					m_freem(mp);
1632 					continue;
1633 				}
1634 				if (in_nam2sin(nam, &sin) != 0 ||
1635 				    ntohs(sin->sin_port) >= IPPORT_RESERVED) {
1636 					nfsstats.srv_errs++;
1637 					m_freem(nam);
1638 					m_freem(mp);
1639 					continue;
1640 				}
1641 				m = nam;
1642 				m->m_next = mp;
1643 				if (slp->ns_recend)
1644 					slp->ns_recend->m_nextpkt = m;
1645 				else
1646 					slp->ns_rec = m;
1647 				slp->ns_recend = m;
1648 				m->m_nextpkt = NULL;
1649 			}
1650 			if (error) {
1651 				if ((so->so_proto->pr_flags & PR_CONNREQUIRED)
1652 					&& error != EWOULDBLOCK) {
1653 					slp->ns_flag |= SLP_DISCONN;
1654 					goto dorecs;
1655 				}
1656 			}
1657 		} while (mp);
1658 	}
1659 
1660 	/*
1661 	 * Now try and process the request records, non-blocking.
1662 	 */
1663 dorecs:
1664 	if (waitflag == M_DONTWAIT &&
1665 		(slp->ns_rec || (slp->ns_flag & (SLP_NEEDQ | SLP_DISCONN))))
1666 		nfsrv_wakenfsd(slp);
1667 
1668 out:
1669 	KERNEL_UNLOCK();
1670 }
1671 
1672 /*
1673  * Try and extract an RPC request from the mbuf data list received on a
1674  * stream socket. The "waitflag" argument indicates whether or not it
1675  * can sleep.
1676  */
1677 int
1678 nfsrv_getstream(struct nfssvc_sock *slp, int waitflag)
1679 {
1680 	struct mbuf *m, **mpp;
1681 	char *cp1, *cp2;
1682 	int len;
1683 	struct mbuf *om, *m2, *recm;
1684 	u_int32_t recmark;
1685 
1686 	if (slp->ns_flag & SLP_GETSTREAM)
1687 		return (0);
1688 	slp->ns_flag |= SLP_GETSTREAM;
1689 	for (;;) {
1690 		if (slp->ns_reclen == 0) {
1691 			if (slp->ns_cc < NFSX_UNSIGNED) {
1692 				slp->ns_flag &= ~SLP_GETSTREAM;
1693 				return (0);
1694 			}
1695 			m = slp->ns_raw;
1696 			if (m->m_len >= NFSX_UNSIGNED) {
1697 				bcopy(mtod(m, caddr_t), &recmark,
1698 				    NFSX_UNSIGNED);
1699 				m->m_data += NFSX_UNSIGNED;
1700 				m->m_len -= NFSX_UNSIGNED;
1701 			} else {
1702 				cp1 = (caddr_t)&recmark;
1703 				cp2 = mtod(m, caddr_t);
1704 				while (cp1 < ((caddr_t)&recmark) + NFSX_UNSIGNED) {
1705 					while (m->m_len == 0) {
1706 						m = m->m_next;
1707 						cp2 = mtod(m, caddr_t);
1708 					}
1709 					*cp1++ = *cp2++;
1710 					m->m_data++;
1711 					m->m_len--;
1712 				}
1713 			}
1714 			slp->ns_cc -= NFSX_UNSIGNED;
1715 			recmark = ntohl(recmark);
1716 			slp->ns_reclen = recmark & ~0x80000000;
1717 			if (recmark & 0x80000000)
1718 				slp->ns_flag |= SLP_LASTFRAG;
1719 			else
1720 				slp->ns_flag &= ~SLP_LASTFRAG;
1721 			if (slp->ns_reclen > NFS_MAXPACKET) {
1722 				slp->ns_flag &= ~SLP_GETSTREAM;
1723 				return (EPERM);
1724 			}
1725 		}
1726 
1727 		/*
1728 		 * Now get the record part.
1729 		 */
1730 		recm = NULL;
1731 		if (slp->ns_cc == slp->ns_reclen) {
1732 			recm = slp->ns_raw;
1733 			slp->ns_raw = slp->ns_rawend = NULL;
1734 			slp->ns_cc = slp->ns_reclen = 0;
1735 		} else if (slp->ns_cc > slp->ns_reclen) {
1736 			len = 0;
1737 			m = slp->ns_raw;
1738 			om = NULL;
1739 			while (len < slp->ns_reclen) {
1740 				if ((len + m->m_len) > slp->ns_reclen) {
1741 					m2 = m_copym(m, 0, slp->ns_reclen - len,
1742 					    waitflag);
1743 					if (m2) {
1744 						if (om) {
1745 							om->m_next = m2;
1746 							recm = slp->ns_raw;
1747 						} else
1748 							recm = m2;
1749 						m->m_data += slp->ns_reclen-len;
1750 						m->m_len -= slp->ns_reclen-len;
1751 						len = slp->ns_reclen;
1752 					} else {
1753 						slp->ns_flag &= ~SLP_GETSTREAM;
1754 						return (EWOULDBLOCK);
1755 					}
1756 				} else if ((len + m->m_len) == slp->ns_reclen) {
1757 					om = m;
1758 					len += m->m_len;
1759 					m = m->m_next;
1760 					recm = slp->ns_raw;
1761 					om->m_next = NULL;
1762 				} else {
1763 					om = m;
1764 					len += m->m_len;
1765 					m = m->m_next;
1766 				}
1767 			}
1768 			slp->ns_raw = m;
1769 			slp->ns_cc -= len;
1770 			slp->ns_reclen = 0;
1771 		} else {
1772 			slp->ns_flag &= ~SLP_GETSTREAM;
1773 			return (0);
1774 		}
1775 
1776 		/*
1777 		 * Accumulate the fragments into a record.
1778 		 */
1779 		mpp = &slp->ns_frag;
1780 		while (*mpp)
1781 			mpp = &((*mpp)->m_next);
1782 		*mpp = recm;
1783 		if (slp->ns_flag & SLP_LASTFRAG) {
1784 			if (slp->ns_recend)
1785 			    slp->ns_recend->m_nextpkt = slp->ns_frag;
1786 			else
1787 			    slp->ns_rec = slp->ns_frag;
1788 			slp->ns_recend = slp->ns_frag;
1789 			slp->ns_frag = NULL;
1790 		}
1791 	}
1792 }
1793 
1794 /*
1795  * Parse an RPC header.
1796  */
1797 int
1798 nfsrv_dorec(struct nfssvc_sock *slp, struct nfsd *nfsd,
1799     struct nfsrv_descript **ndp)
1800 {
1801 	struct mbuf *m, *nam;
1802 	struct nfsrv_descript *nd;
1803 	int error;
1804 
1805 	*ndp = NULL;
1806 	if ((slp->ns_flag & SLP_VALID) == 0 ||
1807 	    (m = slp->ns_rec) == NULL)
1808 		return (ENOBUFS);
1809 	slp->ns_rec = m->m_nextpkt;
1810 	if (slp->ns_rec)
1811 		m->m_nextpkt = NULL;
1812 	else
1813 		slp->ns_recend = NULL;
1814 	if (m->m_type == MT_SONAME) {
1815 		nam = m;
1816 		m = m->m_next;
1817 		nam->m_next = NULL;
1818 	} else
1819 		nam = NULL;
1820 	nd = pool_get(&nfsrv_descript_pl, PR_WAITOK);
1821 	nfs_realign(&m, 10 * NFSX_UNSIGNED);
1822 	nd->nd_md = nd->nd_mrep = m;
1823 	nd->nd_nam2 = nam;
1824 	nd->nd_dpos = mtod(m, caddr_t);
1825 	error = nfs_getreq(nd, nfsd, 1);
1826 	if (error) {
1827 		m_freem(nam);
1828 		pool_put(&nfsrv_descript_pl, nd);
1829 		return (error);
1830 	}
1831 	*ndp = nd;
1832 	nfsd->nfsd_nd = nd;
1833 	return (0);
1834 }
1835 
1836 
1837 /*
1838  * Search for a sleeping nfsd and wake it up.
1839  * SIDE EFFECT: If none found, set NFSD_CHECKSLP flag, so that one of the
1840  * running nfsds will go look for the work in the nfssvc_sock list.
1841  */
1842 void
1843 nfsrv_wakenfsd(struct nfssvc_sock *slp)
1844 {
1845 	struct nfsd	*nfsd;
1846 
1847 	if ((slp->ns_flag & SLP_VALID) == 0)
1848 		return;
1849 
1850 	TAILQ_FOREACH(nfsd, &nfsd_head, nfsd_chain) {
1851 		if (nfsd->nfsd_flag & NFSD_WAITING) {
1852 			nfsd->nfsd_flag &= ~NFSD_WAITING;
1853 			if (nfsd->nfsd_slp)
1854 				panic("nfsd wakeup");
1855 			slp->ns_sref++;
1856 			nfsd->nfsd_slp = slp;
1857 			wakeup_one(nfsd);
1858 			return;
1859 		}
1860 	}
1861 
1862 	slp->ns_flag |= SLP_DOREC;
1863 	nfsd_head_flag |= NFSD_CHECKSLP;
1864 }
1865 #endif /* NFSSERVER */
1866