xref: /openbsd-src/sys/nfs/nfs_socket.c (revision a0747c9f67a4ae71ccb71e62a28d1ea19e06a63c)
1 /*	$OpenBSD: nfs_socket.c,v 1.137 2021/01/02 02:41:42 cheloha 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/domain.h>
50 #include <sys/protosw.h>
51 #include <sys/signalvar.h>
52 #include <sys/socket.h>
53 #include <sys/socketvar.h>
54 #include <sys/syslog.h>
55 #include <sys/tprintf.h>
56 #include <sys/namei.h>
57 #include <sys/pool.h>
58 #include <sys/queue.h>
59 
60 #include <netinet/in.h>
61 #include <netinet/tcp.h>
62 
63 #include <nfs/rpcv2.h>
64 #include <nfs/nfsproto.h>
65 #include <nfs/nfs.h>
66 #include <nfs/xdr_subs.h>
67 #include <nfs/nfsm_subs.h>
68 #include <nfs/nfsmount.h>
69 #include <nfs/nfs_var.h>
70 
71 /* External data, mostly RPC constants in XDR form. */
72 extern u_int32_t rpc_reply, rpc_msgdenied, rpc_mismatch, rpc_vers,
73 	rpc_auth_unix, rpc_msgaccepted, rpc_call, rpc_autherr;
74 extern u_int32_t nfs_prog;
75 extern struct nfsstats nfsstats;
76 extern int nfsv3_procid[NFS_NPROCS];
77 extern int nfs_ticks;
78 
79 extern struct pool nfsrv_descript_pl;
80 
81 /*
82  * There is a congestion window for outstanding rpcs maintained per mount
83  * point. The cwnd size is adjusted in roughly the way that:
84  * Van Jacobson, Congestion avoidance and Control, In "Proceedings of
85  * SIGCOMM '88". ACM, August 1988.
86  * describes for TCP. The cwnd size is chopped in half on a retransmit timeout
87  * and incremented by 1/cwnd when each rpc reply is received and a full cwnd
88  * of rpcs is in progress.
89  * (The sent count and cwnd are scaled for integer arith.)
90  * Variants of "slow start" were tried and were found to be too much of a
91  * performance hit (ave. rtt 3 times larger),
92  * I suspect due to the large rtt that nfs rpcs have.
93  */
94 #define	NFS_CWNDSCALE	256
95 #define	NFS_MAXCWND	(NFS_CWNDSCALE * 32)
96 int nfs_backoff[8] = { 2, 4, 8, 16, 32, 64, 128, 256 };
97 
98 /* RTT estimator */
99 enum nfs_rto_timers nfs_ptimers[NFS_NPROCS] = {
100 	NFS_DEFAULT_TIMER,	/* NULL */
101 	NFS_GETATTR_TIMER,	/* GETATTR */
102 	NFS_DEFAULT_TIMER,	/* SETATTR */
103 	NFS_LOOKUP_TIMER,	/* LOOKUP */
104 	NFS_GETATTR_TIMER,	/* ACCESS */
105 	NFS_READ_TIMER,		/* READLINK */
106 	NFS_READ_TIMER,		/* READ */
107 	NFS_WRITE_TIMER,	/* WRITE */
108 	NFS_DEFAULT_TIMER,	/* CREATE */
109 	NFS_DEFAULT_TIMER,	/* MKDIR */
110 	NFS_DEFAULT_TIMER,	/* SYMLINK */
111 	NFS_DEFAULT_TIMER,	/* MKNOD */
112 	NFS_DEFAULT_TIMER,	/* REMOVE */
113 	NFS_DEFAULT_TIMER,	/* RMDIR */
114 	NFS_DEFAULT_TIMER,	/* RENAME */
115 	NFS_DEFAULT_TIMER,	/* LINK */
116 	NFS_READ_TIMER,		/* READDIR */
117 	NFS_READ_TIMER,		/* READDIRPLUS */
118 	NFS_DEFAULT_TIMER,	/* FSSTAT */
119 	NFS_DEFAULT_TIMER,	/* FSINFO */
120 	NFS_DEFAULT_TIMER,	/* PATHCONF */
121 	NFS_DEFAULT_TIMER,	/* COMMIT */
122 	NFS_DEFAULT_TIMER,	/* NOOP */
123 };
124 
125 void nfs_init_rtt(struct nfsmount *);
126 void nfs_update_rtt(struct nfsreq *);
127 int  nfs_estimate_rto(struct nfsmount *, u_int32_t procnum);
128 
129 void nfs_realign(struct mbuf **, int);
130 void nfs_realign_fixup(struct mbuf *, struct mbuf *, unsigned int *);
131 
132 int nfs_rcvlock(struct nfsreq *);
133 int nfs_receive(struct nfsreq *, struct mbuf **, struct mbuf **);
134 int nfs_reconnect(struct nfsreq *);
135 int nfs_reply(struct nfsreq *);
136 void nfs_msg(struct nfsreq *, char *);
137 void nfs_rcvunlock(int *);
138 
139 int nfsrv_getstream(struct nfssvc_sock *, int);
140 
141 unsigned int nfs_realign_test = 0;
142 unsigned int nfs_realign_count = 0;
143 
144 /* Initialize the RTT estimator state for a new mount point. */
145 void
146 nfs_init_rtt(struct nfsmount *nmp)
147 {
148 	int i;
149 
150 	for (i = 0; i < NFS_MAX_TIMER; i++)
151 		nmp->nm_srtt[i] = NFS_INITRTT;
152 	for (i = 0; i < NFS_MAX_TIMER; i++)
153 		nmp->nm_sdrtt[i] = 0;
154 }
155 
156 /*
157  * Update a mount point's RTT estimator state using data from the
158  * passed-in request.
159  *
160  * Use a gain of 0.125 on the mean and a gain of 0.25 on the deviation.
161  *
162  * NB: Since the timer resolution of NFS_HZ is so course, it can often
163  * result in r_rtt == 0. Since r_rtt == N means that the actual RTT is
164  * between N + dt and N + 2 - dt ticks, add 1 before calculating the
165  * update values.
166  */
167 void
168 nfs_update_rtt(struct nfsreq *rep)
169 {
170 	int t1 = rep->r_rtt + 1;
171 	int index = nfs_ptimers[rep->r_procnum] - 1;
172 	int *srtt = &rep->r_nmp->nm_srtt[index];
173 	int *sdrtt = &rep->r_nmp->nm_sdrtt[index];
174 
175 	t1 -= *srtt >> 3;
176 	*srtt += t1;
177 	if (t1 < 0)
178 		t1 = -t1;
179 	t1 -= *sdrtt >> 2;
180 	*sdrtt += t1;
181 }
182 
183 /*
184  * Estimate RTO for an NFS RPC sent via an unreliable datagram.
185  *
186  * Use the mean and mean deviation of RTT for the appropriate type
187  * of RPC for the frequent RPCs and a default for the others.
188  * The justification for doing "other" this way is that these RPCs
189  * happen so infrequently that timer est. would probably be stale.
190  * Also, since many of these RPCs are non-idempotent, a conservative
191  * timeout is desired.
192  *
193  * getattr, lookup - A+2D
194  * read, write     - A+4D
195  * other           - nm_timeo
196  */
197 int
198 nfs_estimate_rto(struct nfsmount *nmp, u_int32_t procnum)
199 {
200 	enum nfs_rto_timers timer = nfs_ptimers[procnum];
201 	int index = timer - 1;
202 	int rto;
203 
204 	switch (timer) {
205 	case NFS_GETATTR_TIMER:
206 	case NFS_LOOKUP_TIMER:
207 		rto = ((nmp->nm_srtt[index] + 3) >> 2) +
208 				((nmp->nm_sdrtt[index] + 1) >> 1);
209 		break;
210 	case NFS_READ_TIMER:
211 	case NFS_WRITE_TIMER:
212 		rto = ((nmp->nm_srtt[index] + 7) >> 3) +
213 				(nmp->nm_sdrtt[index] + 1);
214 		break;
215 	default:
216 		rto = nmp->nm_timeo;
217 		return (rto);
218 	}
219 
220 	if (rto < NFS_MINRTO)
221 		rto = NFS_MINRTO;
222 	else if (rto > NFS_MAXRTO)
223 		rto = NFS_MAXRTO;
224 
225 	return (rto);
226 }
227 
228 
229 
230 /*
231  * Initialize sockets and congestion for a new NFS connection.
232  * We do not free the sockaddr if error.
233  */
234 int
235 nfs_connect(struct nfsmount *nmp, struct nfsreq *rep)
236 {
237 	struct socket *so;
238 	int s, error, rcvreserve, sndreserve;
239 	struct sockaddr *saddr;
240 	struct sockaddr_in *sin;
241 	struct mbuf *nam = NULL, *mopt = NULL;
242 
243 	if (!(nmp->nm_sotype == SOCK_DGRAM || nmp->nm_sotype == SOCK_STREAM))
244 		return (EINVAL);
245 
246 	nmp->nm_so = NULL;
247 	saddr = mtod(nmp->nm_nam, struct sockaddr *);
248 	error = socreate(saddr->sa_family, &nmp->nm_so, nmp->nm_sotype,
249 	    nmp->nm_soproto);
250 	if (error) {
251 		nfs_disconnect(nmp);
252 		return (error);
253 	}
254 
255 	/* Allocate mbufs possibly waiting before grabbing the socket lock. */
256 	if (nmp->nm_sotype == SOCK_STREAM || saddr->sa_family == AF_INET)
257 		MGET(mopt, M_WAIT, MT_SOOPTS);
258 	if (saddr->sa_family == AF_INET)
259 		MGET(nam, M_WAIT, MT_SONAME);
260 
261 	so = nmp->nm_so;
262 	s = solock(so);
263 	nmp->nm_soflags = so->so_proto->pr_flags;
264 
265 	/*
266 	 * Some servers require that the client port be a reserved port number.
267 	 * We always allocate a reserved port, as this prevents filehandle
268 	 * disclosure through UDP port capture.
269 	 */
270 	if (saddr->sa_family == AF_INET) {
271 		int *ip;
272 
273 		mopt->m_len = sizeof(int);
274 		ip = mtod(mopt, int *);
275 		*ip = IP_PORTRANGE_LOW;
276 		error = sosetopt(so, IPPROTO_IP, IP_PORTRANGE, mopt);
277 		if (error)
278 			goto bad;
279 
280 		sin = mtod(nam, struct sockaddr_in *);
281 		memset(sin, 0, sizeof(*sin));
282 		sin->sin_len = nam->m_len = sizeof(struct sockaddr_in);
283 		sin->sin_family = AF_INET;
284 		sin->sin_addr.s_addr = INADDR_ANY;
285 		sin->sin_port = htons(0);
286 		error = sobind(so, nam, &proc0);
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 		error = soconnect(so, nmp->nm_nam);
309 		if (error)
310 			goto bad;
311 
312 		/*
313 		 * Wait for the connection to complete. Cribbed from the
314 		 * connect system call but with the wait timing out so
315 		 * that interruptible mounts don't hang here for a long time.
316 		 */
317 		while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
318 			sosleep_nsec(so, &so->so_timeo, PSOCK, "nfscon",
319 			    SEC_TO_NSEC(2));
320 			if ((so->so_state & SS_ISCONNECTING) &&
321 			    so->so_error == 0 && rep &&
322 			    (error = nfs_sigintr(nmp, rep, rep->r_procp)) != 0){
323 				so->so_state &= ~SS_ISCONNECTING;
324 				goto bad;
325 			}
326 		}
327 		if (so->so_error) {
328 			error = so->so_error;
329 			so->so_error = 0;
330 			goto bad;
331 		}
332 	}
333 	/*
334 	 * Always set receive timeout to detect server crash and reconnect.
335 	 * Otherwise, we can get stuck in soreceive forever.
336 	 */
337 	so->so_rcv.sb_timeo_nsecs = SEC_TO_NSEC(5);
338 	if (nmp->nm_flag & (NFSMNT_SOFT | NFSMNT_INT))
339 		so->so_snd.sb_timeo_nsecs = SEC_TO_NSEC(5);
340 	else
341 		so->so_snd.sb_timeo_nsecs = INFSLP;
342 	if (nmp->nm_sotype == SOCK_DGRAM) {
343 		sndreserve = nmp->nm_wsize + NFS_MAXPKTHDR;
344 		rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
345 		    NFS_MAXPKTHDR) * 2;
346 	} else if (nmp->nm_sotype == SOCK_STREAM) {
347 		if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
348 			*mtod(mopt, int32_t *) = 1;
349 			mopt->m_len = sizeof(int32_t);
350 			sosetopt(so, SOL_SOCKET, SO_KEEPALIVE, mopt);
351 		}
352 		if (so->so_proto->pr_protocol == IPPROTO_TCP) {
353 			*mtod(mopt, int32_t *) = 1;
354 			mopt->m_len = sizeof(int32_t);
355 			sosetopt(so, IPPROTO_TCP, TCP_NODELAY, mopt);
356 		}
357 		sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR +
358 		    sizeof (u_int32_t)) * 2;
359 		rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR +
360 		    sizeof (u_int32_t)) * 2;
361 	} else {
362 		panic("%s: nm_sotype %d", __func__, nmp->nm_sotype);
363 	}
364 	error = soreserve(so, sndreserve, rcvreserve);
365 	if (error)
366 		goto bad;
367 	so->so_rcv.sb_flags |= SB_NOINTR;
368 	so->so_snd.sb_flags |= SB_NOINTR;
369 	sounlock(so, s);
370 
371 	m_freem(mopt);
372 	m_freem(nam);
373 
374 	/* Initialize other non-zero congestion variables */
375 	nfs_init_rtt(nmp);
376 	nmp->nm_cwnd = NFS_MAXCWND / 2;	    /* Initial send window */
377 	nmp->nm_sent = 0;
378 	nmp->nm_timeouts = 0;
379 	return (0);
380 
381 bad:
382 	sounlock(so, s);
383 
384 	m_freem(mopt);
385 	m_freem(nam);
386 
387 	nfs_disconnect(nmp);
388 	return (error);
389 }
390 
391 /*
392  * Reconnect routine:
393  * Called when a connection is broken on a reliable protocol.
394  * - clean up the old socket
395  * - nfs_connect() again
396  * - set R_MUSTRESEND for all outstanding requests on mount point
397  * If this fails the mount point is DEAD!
398  * nb: Must be called with the nfs_sndlock() set on the mount point.
399  */
400 int
401 nfs_reconnect(struct nfsreq *rep)
402 {
403 	struct nfsreq *rp;
404 	struct nfsmount *nmp = rep->r_nmp;
405 	int error;
406 
407 	nfs_disconnect(nmp);
408 	while ((error = nfs_connect(nmp, rep)) != 0) {
409 		if (error == EINTR || error == ERESTART)
410 			return (EINTR);
411 		tsleep_nsec(&nowake, PSOCK, "nfsrecon", SEC_TO_NSEC(1));
412 	}
413 
414 	/*
415 	 * Loop through outstanding request list and fix up all requests
416 	 * on old socket.
417 	 */
418 	TAILQ_FOREACH(rp, &nmp->nm_reqsq, r_chain) {
419 		rp->r_flags |= R_MUSTRESEND;
420 		rp->r_rexmit = 0;
421 	}
422 	return (0);
423 }
424 
425 /*
426  * NFS disconnect. Clean up and unlink.
427  */
428 void
429 nfs_disconnect(struct nfsmount *nmp)
430 {
431 	struct socket *so;
432 
433 	if (nmp->nm_so) {
434 		so = nmp->nm_so;
435 		nmp->nm_so = NULL;
436 		soshutdown(so, SHUT_RDWR);
437 		soclose(so, 0);
438 	}
439 }
440 
441 /*
442  * This is the nfs send routine. For connection based socket types, it
443  * must be called with an nfs_sndlock() on the socket.
444  * "rep == NULL" indicates that it has been called from a server.
445  * For the client side:
446  * - return EINTR if the RPC is terminated, 0 otherwise
447  * - set R_MUSTRESEND if the send fails for any reason
448  * - do any cleanup required by recoverable socket errors (???)
449  * For the server side:
450  * - return EINTR or ERESTART if interrupted by a signal
451  * - return EPIPE if a connection is lost for connection based sockets (TCP...)
452  * - do any cleanup required by recoverable socket errors (???)
453  */
454 int
455 nfs_send(struct socket *so, struct mbuf *nam, struct mbuf *top,
456     struct nfsreq *rep)
457 {
458 	struct mbuf *sendnam;
459 	int error, soflags, flags;
460 
461 	if (rep) {
462 		if (rep->r_flags & R_SOFTTERM) {
463 			m_freem(top);
464 			return (EINTR);
465 		}
466 		if ((so = rep->r_nmp->nm_so) == NULL) {
467 			rep->r_flags |= R_MUSTRESEND;
468 			m_freem(top);
469 			return (0);
470 		}
471 		rep->r_flags &= ~R_MUSTRESEND;
472 		soflags = rep->r_nmp->nm_soflags;
473 	} else
474 		soflags = so->so_proto->pr_flags;
475 	if ((soflags & PR_CONNREQUIRED) || (so->so_state & SS_ISCONNECTED))
476 		sendnam = NULL;
477 	else
478 		sendnam = nam;
479 	flags = 0;
480 
481 	error = sosend(so, sendnam, NULL, top, NULL, flags);
482 	if (error) {
483 		if (rep) {
484 			/*
485 			 * Deal with errors for the client side.
486 			 */
487 			if (rep->r_flags & R_SOFTTERM)
488 				error = EINTR;
489 			else
490 				rep->r_flags |= R_MUSTRESEND;
491 		}
492 
493 		/*
494 		 * Handle any recoverable (soft) socket errors here. (???)
495 		 */
496 		if (error != EINTR && error != ERESTART &&
497 		    error != EWOULDBLOCK && error != EPIPE)
498 			error = 0;
499 	}
500 	return (error);
501 }
502 
503 #ifdef NFSCLIENT
504 /*
505  * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
506  * done by soreceive(), but for SOCK_STREAM we must deal with the Record
507  * Mark and consolidate the data into a new mbuf list.
508  * nb: Sometimes TCP passes the data up to soreceive() in long lists of
509  *     small mbufs.
510  * For SOCK_STREAM we must be very careful to read an entire record once
511  * we have read any of it, even if the system call has been interrupted.
512  */
513 int
514 nfs_receive(struct nfsreq *rep, struct mbuf **aname, struct mbuf **mp)
515 {
516 	struct socket *so;
517 	struct uio auio;
518 	struct iovec aio;
519 	struct mbuf *m;
520 	struct mbuf *control;
521 	u_int32_t len;
522 	struct mbuf **getnam;
523 	int error, sotype, rcvflg;
524 	struct proc *p = curproc;	/* XXX */
525 
526 	/*
527 	 * Set up arguments for soreceive()
528 	 */
529 	*mp = NULL;
530 	*aname = NULL;
531 	sotype = rep->r_nmp->nm_sotype;
532 
533 	/*
534 	 * For reliable protocols, lock against other senders/receivers
535 	 * in case a reconnect is necessary.
536 	 * For SOCK_STREAM, first get the Record Mark to find out how much
537 	 * more there is to get.
538 	 * We must lock the socket against other receivers
539 	 * until we have an entire rpc request/reply.
540 	 */
541 	if (sotype != SOCK_DGRAM) {
542 		error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
543 		if (error)
544 			return (error);
545 tryagain:
546 		/*
547 		 * Check for fatal errors and resending request.
548 		 */
549 		/*
550 		 * Ugh: If a reconnect attempt just happened, nm_so
551 		 * would have changed. NULL indicates a failed
552 		 * attempt that has essentially shut down this
553 		 * mount point.
554 		 */
555 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
556 			nfs_sndunlock(&rep->r_nmp->nm_flag);
557 			return (EINTR);
558 		}
559 		so = rep->r_nmp->nm_so;
560 		if (!so) {
561 			error = nfs_reconnect(rep);
562 			if (error) {
563 				nfs_sndunlock(&rep->r_nmp->nm_flag);
564 				return (error);
565 			}
566 			goto tryagain;
567 		}
568 		while (rep->r_flags & R_MUSTRESEND) {
569 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
570 			nfsstats.rpcretries++;
571 			rep->r_rtt = 0;
572 			rep->r_flags &= ~R_TIMING;
573 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
574 			if (error) {
575 				if (error == EINTR || error == ERESTART ||
576 				    (error = nfs_reconnect(rep)) != 0) {
577 					nfs_sndunlock(&rep->r_nmp->nm_flag);
578 					return (error);
579 				}
580 				goto tryagain;
581 			}
582 		}
583 		nfs_sndunlock(&rep->r_nmp->nm_flag);
584 		if (sotype == SOCK_STREAM) {
585 			aio.iov_base = (caddr_t) &len;
586 			aio.iov_len = sizeof(u_int32_t);
587 			auio.uio_iov = &aio;
588 			auio.uio_iovcnt = 1;
589 			auio.uio_segflg = UIO_SYSSPACE;
590 			auio.uio_rw = UIO_READ;
591 			auio.uio_offset = 0;
592 			auio.uio_resid = sizeof(u_int32_t);
593 			auio.uio_procp = p;
594 			do {
595 				rcvflg = MSG_WAITALL;
596 				error = soreceive(so, NULL, &auio, NULL, NULL,
597 				    &rcvflg, 0);
598 				if (error == EWOULDBLOCK && rep) {
599 					if (rep->r_flags & R_SOFTTERM)
600 						return (EINTR);
601 					/*
602 					 * looks like the server died after it
603 					 * received the request, make sure
604 					 * that we will retransmit and we
605 					 * don't get stuck here forever.
606 					 */
607 					if (rep->r_rexmit >=
608 					    rep->r_nmp->nm_retry) {
609 						nfsstats.rpctimeouts++;
610 						error = EPIPE;
611 					}
612 				}
613 			} while (error == EWOULDBLOCK);
614 			if (!error && auio.uio_resid > 0) {
615 			    log(LOG_INFO,
616 				 "short receive (%zu/%zu) from nfs server %s\n",
617 				 sizeof(u_int32_t) - auio.uio_resid,
618 				 sizeof(u_int32_t),
619 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
620 			    error = EPIPE;
621 			}
622 			if (error)
623 				goto errout;
624 
625 			len = ntohl(len) & ~0x80000000;
626 			/*
627 			 * This is SERIOUS! We are out of sync with the sender
628 			 * and forcing a disconnect/reconnect is all I can do.
629 			 */
630 			if (len > NFS_MAXPACKET) {
631 			    log(LOG_ERR, "%s (%u) from nfs server %s\n",
632 				"impossible packet length",
633 				len,
634 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
635 			    error = EFBIG;
636 			    goto errout;
637 			}
638 			auio.uio_resid = len;
639 			do {
640 			    rcvflg = MSG_WAITALL;
641 			    error =  soreceive(so, NULL, &auio, mp, NULL,
642 			        &rcvflg, 0);
643 			} while (error == EWOULDBLOCK || error == EINTR ||
644 			    error == ERESTART);
645 			if (!error && auio.uio_resid > 0) {
646 				log(LOG_INFO, "short receive (%zu/%u) from "
647 				    "nfs server %s\n", len - auio.uio_resid,
648 				    len, rep->r_nmp->nm_mountp->
649 				    mnt_stat.f_mntfromname);
650 				error = EPIPE;
651 			}
652 		} else {
653 			/*
654 			 * NB: Since uio_resid is big, MSG_WAITALL is ignored
655 			 * and soreceive() will return when it has either a
656 			 * control msg or a data msg.
657 			 * We have no use for control msg., but must grab them
658 			 * and then throw them away so we know what is going
659 			 * on.
660 			 */
661 			auio.uio_resid = len = 100000000; /* Anything Big */
662 			auio.uio_procp = p;
663 			do {
664 				rcvflg = 0;
665 				error = soreceive(so, NULL, &auio, mp, &control,
666 				    &rcvflg, 0);
667 				m_freem(control);
668 				if (error == EWOULDBLOCK && rep) {
669 					if (rep->r_flags & R_SOFTTERM)
670 						return (EINTR);
671 				}
672 			} while (error == EWOULDBLOCK ||
673 			    (!error && *mp == NULL && control));
674 			if ((rcvflg & MSG_EOR) == 0)
675 				printf("Egad!!\n");
676 			if (!error && *mp == NULL)
677 				error = EPIPE;
678 			len -= auio.uio_resid;
679 		}
680 errout:
681 		if (error && error != EINTR && error != ERESTART) {
682 			m_freemp(mp);
683 			if (error != EPIPE)
684 				log(LOG_INFO,
685 				    "receive error %d from nfs server %s\n",
686 				    error,
687 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
688 			error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
689 			if (!error) {
690 				error = nfs_reconnect(rep);
691 				if (!error)
692 					goto tryagain;
693 				nfs_sndunlock(&rep->r_nmp->nm_flag);
694 			}
695 		}
696 	} else {
697 		if ((so = rep->r_nmp->nm_so) == NULL)
698 			return (EACCES);
699 		if (so->so_state & SS_ISCONNECTED)
700 			getnam = NULL;
701 		else
702 			getnam = aname;
703 		auio.uio_resid = len = 1000000;
704 		auio.uio_procp = p;
705 		do {
706 			rcvflg = 0;
707 			error = soreceive(so, getnam, &auio, mp, NULL,
708 			    &rcvflg, 0);
709 			if (error == EWOULDBLOCK &&
710 			    (rep->r_flags & R_SOFTTERM))
711 				return (EINTR);
712 		} while (error == EWOULDBLOCK);
713 		len -= auio.uio_resid;
714 	}
715 	if (error)
716 		m_freemp(mp);
717 	/*
718 	 * Search for any mbufs that are not a multiple of 4 bytes long
719 	 * or with m_data not longword aligned.
720 	 * These could cause pointer alignment problems, so copy them to
721 	 * well aligned mbufs.
722 	 */
723 	nfs_realign(mp, 5 * NFSX_UNSIGNED);
724 	return (error);
725 }
726 
727 /*
728  * Implement receipt of reply on a socket.
729  * We must search through the list of received datagrams matching them
730  * with outstanding requests using the xid, until ours is found.
731  */
732 int
733 nfs_reply(struct nfsreq *myrep)
734 {
735 	struct nfsreq *rep;
736 	struct nfsmount *nmp = myrep->r_nmp;
737 	struct nfsm_info	info;
738 	struct mbuf *nam;
739 	u_int32_t rxid, *tl, t1;
740 	caddr_t cp2;
741 	int error;
742 
743 	/*
744 	 * Loop around until we get our own reply
745 	 */
746 	for (;;) {
747 		/*
748 		 * Lock against other receivers so that I don't get stuck in
749 		 * sbwait() after someone else has received my reply for me.
750 		 * Also necessary for connection based protocols to avoid
751 		 * race conditions during a reconnect.
752 		 */
753 		error = nfs_rcvlock(myrep);
754 		if (error)
755 			return (error == EALREADY ? 0 : error);
756 
757 		/*
758 		 * Get the next Rpc reply off the socket
759 		 */
760 		error = nfs_receive(myrep, &nam, &info.nmi_mrep);
761 		nfs_rcvunlock(&nmp->nm_flag);
762 		if (error) {
763 
764 			/*
765 			 * Ignore routing errors on connectionless protocols??
766 			 */
767 			if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
768 				if (nmp->nm_so)
769 					nmp->nm_so->so_error = 0;
770 				continue;
771 			}
772 			return (error);
773 		}
774 		m_freem(nam);
775 
776 		/*
777 		 * Get the xid and check that it is an rpc reply
778 		 */
779 		info.nmi_md = info.nmi_mrep;
780 		info.nmi_dpos = mtod(info.nmi_md, caddr_t);
781 		nfsm_dissect(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
782 		rxid = *tl++;
783 		if (*tl != rpc_reply) {
784 			nfsstats.rpcinvalid++;
785 			m_freem(info.nmi_mrep);
786 nfsmout:
787 			continue;
788 		}
789 
790 		/*
791 		 * Loop through the request list to match up the reply
792 		 * Iff no match, just drop the datagram
793 		 */
794 		TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
795 			if (rep->r_mrep == NULL && rxid == rep->r_xid) {
796 				/* Found it.. */
797 				rep->r_mrep = info.nmi_mrep;
798 				rep->r_md = info.nmi_md;
799 				rep->r_dpos = info.nmi_dpos;
800 
801 				/*
802 				 * Update congestion window.
803 				 * Do the additive increase of
804 				 * one rpc/rtt.
805 				 */
806 				if (nmp->nm_cwnd <= nmp->nm_sent) {
807 					nmp->nm_cwnd +=
808 					   (NFS_CWNDSCALE * NFS_CWNDSCALE +
809 					   (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
810 					if (nmp->nm_cwnd > NFS_MAXCWND)
811 						nmp->nm_cwnd = NFS_MAXCWND;
812 				}
813 				rep->r_flags &= ~R_SENT;
814 				nmp->nm_sent -= NFS_CWNDSCALE;
815 
816 				if (rep->r_flags & R_TIMING)
817 					nfs_update_rtt(rep);
818 
819 				nmp->nm_timeouts = 0;
820 				break;
821 			}
822 		}
823 		/*
824 		 * If not matched to a request, drop it.
825 		 * If it's mine, get out.
826 		 */
827 		if (rep == 0) {
828 			nfsstats.rpcunexpected++;
829 			m_freem(info.nmi_mrep);
830 		} else if (rep == myrep) {
831 			if (rep->r_mrep == NULL)
832 				panic("nfsreply nil");
833 			return (0);
834 		}
835 	}
836 }
837 
838 /*
839  * nfs_request - goes something like this
840  *	- fill in request struct
841  *	- links it into list
842  *	- calls nfs_send() for first transmit
843  *	- calls nfs_receive() to get reply
844  *	- break down rpc header and return with nfs reply pointed to
845  *	  by mrep or error
846  * nb: always frees up mreq mbuf list
847  */
848 int
849 nfs_request(struct vnode *vp, int procnum, struct nfsm_info *infop)
850 {
851 	struct mbuf *m;
852 	u_int32_t *tl;
853 	struct nfsmount *nmp;
854 	caddr_t cp2;
855 	int t1, i, error = 0;
856 	int trylater_delay;
857 	struct nfsreq *rep;
858 	struct nfsm_info info;
859 
860 	rep = pool_get(&nfsreqpl, PR_WAITOK);
861 	rep->r_nmp = VFSTONFS(vp->v_mount);
862 	rep->r_vp = vp;
863 	rep->r_procp = infop->nmi_procp;
864 	rep->r_procnum = procnum;
865 
866 	/* empty mbuf for AUTH_UNIX header */
867 	rep->r_mreq = m_gethdr(M_WAIT, MT_DATA);
868 	rep->r_mreq->m_next = infop->nmi_mreq;
869 	rep->r_mreq->m_len = 0;
870 	m_calchdrlen(rep->r_mreq);
871 
872 	trylater_delay = NFS_MINTIMEO;
873 
874 	nmp = rep->r_nmp;
875 
876 	/* Get the RPC header with authorization. */
877 	nfsm_rpchead(rep, infop->nmi_cred, RPCAUTH_UNIX);
878 	m = rep->r_mreq;
879 
880 	/*
881 	 * For stream protocols, insert a Sun RPC Record Mark.
882 	 */
883 	if (nmp->nm_sotype == SOCK_STREAM) {
884 		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
885 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
886 		    (m->m_pkthdr.len - NFSX_UNSIGNED));
887 	}
888 
889 tryagain:
890 	rep->r_rtt = rep->r_rexmit = 0;
891 	if (nfs_ptimers[rep->r_procnum] != NFS_DEFAULT_TIMER)
892 		rep->r_flags = R_TIMING;
893 	else
894 		rep->r_flags = 0;
895 	rep->r_mrep = NULL;
896 
897 	/*
898 	 * Do the client side RPC.
899 	 */
900 	nfsstats.rpcrequests++;
901 	/*
902 	 * Chain request into list of outstanding requests. Be sure
903 	 * to put it LAST so timer finds oldest requests first.
904 	 */
905 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
906 		timeout_add(&nmp->nm_rtimeout, nfs_ticks);
907 	TAILQ_INSERT_TAIL(&nmp->nm_reqsq, rep, r_chain);
908 
909 	/*
910 	 * If backing off another request or avoiding congestion, don't
911 	 * send this one now but let timer do it. If not timing a request,
912 	 * do it now.
913 	 */
914 	if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
915 		(nmp->nm_flag & NFSMNT_DUMBTIMR) ||
916 		nmp->nm_sent < nmp->nm_cwnd)) {
917 		if (nmp->nm_soflags & PR_CONNREQUIRED)
918 			error = nfs_sndlock(&nmp->nm_flag, rep);
919 		if (!error) {
920 			error = nfs_send(nmp->nm_so, nmp->nm_nam,
921 			    m_copym(m, 0, M_COPYALL, M_WAIT), rep);
922 			if (nmp->nm_soflags & PR_CONNREQUIRED)
923 				nfs_sndunlock(&nmp->nm_flag);
924 		}
925 		if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
926 			nmp->nm_sent += NFS_CWNDSCALE;
927 			rep->r_flags |= R_SENT;
928 		}
929 	} else {
930 		rep->r_rtt = -1;
931 	}
932 
933 	/*
934 	 * Wait for the reply from our send or the timer's.
935 	 */
936 	if (!error || error == EPIPE)
937 		error = nfs_reply(rep);
938 
939 	/*
940 	 * RPC done, unlink the request.
941 	 */
942 	TAILQ_REMOVE(&nmp->nm_reqsq, rep, r_chain);
943 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
944 		timeout_del(&nmp->nm_rtimeout);
945 
946 	/*
947 	 * Decrement the outstanding request count.
948 	 */
949 	if (rep->r_flags & R_SENT) {
950 		rep->r_flags &= ~R_SENT;	/* paranoia */
951 		nmp->nm_sent -= NFS_CWNDSCALE;
952 	}
953 
954 	/*
955 	 * If there was a successful reply and a tprintf msg.
956 	 * tprintf a response.
957 	 */
958 	if (!error && (rep->r_flags & R_TPRINTFMSG))
959 		nfs_msg(rep, "is alive again");
960 	info.nmi_mrep = rep->r_mrep;
961 	info.nmi_md = rep->r_md;
962 	info.nmi_dpos = rep->r_dpos;
963 	if (error) {
964 		infop->nmi_mrep = NULL;
965 		goto nfsmout1;
966 	}
967 
968 	/*
969 	 * break down the rpc header and check if ok
970 	 */
971 	nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
972 	if (*tl++ == rpc_msgdenied) {
973 		if (*tl == rpc_mismatch)
974 			error = EOPNOTSUPP;
975 		else
976 			error = EACCES;	/* Should be EAUTH. */
977 		infop->nmi_mrep = NULL;
978 		goto nfsmout1;
979 	}
980 
981 	/*
982 	 * Since we only support RPCAUTH_UNIX atm we step over the
983 	 * reply verifer type, and in the (error) case that there really
984 	 * is any data in it, we advance over it.
985 	 */
986 	tl++;			/* Step over verifer type */
987 	i = fxdr_unsigned(int32_t, *tl);
988 	if (i > 0)
989 		nfsm_adv(nfsm_rndup(i));	/* Should not happen */
990 
991 	nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
992 	/* 0 == ok */
993 	if (*tl == 0) {
994 		nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
995 		if (*tl != 0) {
996 			error = fxdr_unsigned(int, *tl);
997 			if ((nmp->nm_flag & NFSMNT_NFSV3) &&
998 			    error == NFSERR_TRYLATER) {
999 				m_freem(info.nmi_mrep);
1000 				error = 0;
1001 				tsleep_nsec(&nowake, PSOCK, "nfsretry",
1002 				    SEC_TO_NSEC(trylater_delay));
1003 				trylater_delay *= NFS_TIMEOUTMUL;
1004 				if (trylater_delay > NFS_MAXTIMEO)
1005 					trylater_delay = NFS_MAXTIMEO;
1006 
1007 				goto tryagain;
1008 			}
1009 
1010 			/*
1011 			 * If the File Handle was stale, invalidate the
1012 			 * lookup cache, just in case.
1013 			 */
1014 			if (error == ESTALE)
1015 				cache_purge(rep->r_vp);
1016 		}
1017 		goto nfsmout;
1018 	}
1019 
1020 	error = EPROTONOSUPPORT;
1021 
1022 nfsmout:
1023 	infop->nmi_mrep = info.nmi_mrep;
1024 	infop->nmi_md = info.nmi_md;
1025 	infop->nmi_dpos = info.nmi_dpos;
1026 nfsmout1:
1027 	m_freem(rep->r_mreq);
1028 	pool_put(&nfsreqpl, rep);
1029 	return (error);
1030 }
1031 #endif /* NFSCLIENT */
1032 
1033 /*
1034  * Generate the rpc reply header
1035  * siz arg. is used to decide if adding a cluster is worthwhile
1036  */
1037 int
1038 nfs_rephead(int siz, struct nfsrv_descript *nd, struct nfssvc_sock *slp,
1039     int err, struct mbuf **mrq, struct mbuf **mbp)
1040 {
1041 	u_int32_t *tl;
1042 	struct mbuf *mreq;
1043 	struct mbuf *mb;
1044 
1045 	MGETHDR(mreq, M_WAIT, MT_DATA);
1046 	mb = mreq;
1047 	/*
1048 	 * If this is a big reply, use a cluster else
1049 	 * try and leave leading space for the lower level headers.
1050 	 */
1051 	siz += RPC_REPLYSIZ;
1052 	if (siz >= MHLEN - max_hdr) {
1053 		MCLGET(mreq, M_WAIT);
1054 	} else
1055 		mreq->m_data += max_hdr;
1056 	tl = mtod(mreq, u_int32_t *);
1057 	mreq->m_len = 6 * NFSX_UNSIGNED;
1058 	*tl++ = txdr_unsigned(nd->nd_retxid);
1059 	*tl++ = rpc_reply;
1060 	if (err == ERPCMISMATCH || (err & NFSERR_AUTHERR)) {
1061 		*tl++ = rpc_msgdenied;
1062 		if (err & NFSERR_AUTHERR) {
1063 			*tl++ = rpc_autherr;
1064 			*tl = txdr_unsigned(err & ~NFSERR_AUTHERR);
1065 			mreq->m_len -= NFSX_UNSIGNED;
1066 		} else {
1067 			*tl++ = rpc_mismatch;
1068 			*tl++ = txdr_unsigned(RPC_VER2);
1069 			*tl = txdr_unsigned(RPC_VER2);
1070 		}
1071 	} else {
1072 		*tl++ = rpc_msgaccepted;
1073 
1074 		/* AUTH_UNIX requires RPCAUTH_NULL. */
1075 		*tl++ = 0;
1076 		*tl++ = 0;
1077 
1078 		switch (err) {
1079 		case EPROGUNAVAIL:
1080 			*tl = txdr_unsigned(RPC_PROGUNAVAIL);
1081 			break;
1082 		case EPROGMISMATCH:
1083 			*tl = txdr_unsigned(RPC_PROGMISMATCH);
1084 			tl = nfsm_build(&mb, 2 * NFSX_UNSIGNED);
1085 			*tl++ = txdr_unsigned(NFS_VER2);
1086 			*tl = txdr_unsigned(NFS_VER3);
1087 			break;
1088 		case EPROCUNAVAIL:
1089 			*tl = txdr_unsigned(RPC_PROCUNAVAIL);
1090 			break;
1091 		case EBADRPC:
1092 			*tl = txdr_unsigned(RPC_GARBAGE);
1093 			break;
1094 		default:
1095 			*tl = 0;
1096 			if (err != NFSERR_RETVOID) {
1097 				tl = nfsm_build(&mb, NFSX_UNSIGNED);
1098 				if (err)
1099 				    *tl = txdr_unsigned(nfsrv_errmap(nd, err));
1100 				else
1101 				    *tl = 0;
1102 			}
1103 			break;
1104 		};
1105 	}
1106 
1107 	*mrq = mreq;
1108 	if (mbp != NULL)
1109 		*mbp = mb;
1110 	if (err != 0 && err != NFSERR_RETVOID)
1111 		nfsstats.srvrpc_errs++;
1112 	return (0);
1113 }
1114 
1115 /*
1116  * nfs timer routine
1117  * Scan the nfsreq list and retranmit any requests that have timed out.
1118  */
1119 void
1120 nfs_timer(void *arg)
1121 {
1122 	struct nfsmount *nmp = arg;
1123 	struct nfsreq *rep;
1124 	struct mbuf *m;
1125 	struct socket *so;
1126 	int timeo, error;
1127 
1128 	NET_LOCK();
1129 	TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
1130 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
1131 			continue;
1132 		if (nfs_sigintr(nmp, rep, rep->r_procp)) {
1133 			rep->r_flags |= R_SOFTTERM;
1134 			continue;
1135 		}
1136 		if (rep->r_rtt >= 0) {
1137 			rep->r_rtt++;
1138 			if (nmp->nm_flag & NFSMNT_DUMBTIMR)
1139 				timeo = nmp->nm_timeo;
1140 			else
1141 				timeo = nfs_estimate_rto(nmp, rep->r_procnum);
1142 			if (nmp->nm_timeouts > 0)
1143 				timeo *= nfs_backoff[nmp->nm_timeouts - 1];
1144 			if (rep->r_rtt <= timeo)
1145 				continue;
1146 			if (nmp->nm_timeouts < nitems(nfs_backoff))
1147 				nmp->nm_timeouts++;
1148 		}
1149 
1150 		/* Check for server not responding. */
1151 		if ((rep->r_flags & R_TPRINTFMSG) == 0 && rep->r_rexmit > 4) {
1152 			nfs_msg(rep, "not responding");
1153 			rep->r_flags |= R_TPRINTFMSG;
1154 		}
1155 		if (rep->r_rexmit >= nmp->nm_retry) {	/* too many */
1156 			nfsstats.rpctimeouts++;
1157 			rep->r_flags |= R_SOFTTERM;
1158 			continue;
1159 		}
1160 		if (nmp->nm_sotype != SOCK_DGRAM) {
1161 			if (++rep->r_rexmit > NFS_MAXREXMIT)
1162 				rep->r_rexmit = NFS_MAXREXMIT;
1163 			continue;
1164 		}
1165 
1166 		if ((so = nmp->nm_so) == NULL)
1167 			continue;
1168 
1169 		/*
1170 		 * If there is enough space and the window allows..
1171 		 *	Resend it
1172 		 * Set r_rtt to -1 in case we fail to send it now.
1173 		 */
1174 		rep->r_rtt = -1;
1175 		if (sbspace(so, &so->so_snd) >= rep->r_mreq->m_pkthdr.len &&
1176 		   ((nmp->nm_flag & NFSMNT_DUMBTIMR) ||
1177 		    (rep->r_flags & R_SENT) ||
1178 		    nmp->nm_sent < nmp->nm_cwnd) &&
1179 		   (m = m_copym(rep->r_mreq, 0, M_COPYALL, M_DONTWAIT))){
1180 			if ((nmp->nm_flag & NFSMNT_NOCONN) == 0)
1181 			    	error = (*so->so_proto->pr_usrreq)(so, PRU_SEND,
1182 				    m, NULL, NULL, curproc);
1183 			else
1184 			    	error = (*so->so_proto->pr_usrreq)(so, PRU_SEND,
1185 				    m, nmp->nm_nam, NULL, curproc);
1186 			if (error) {
1187 				if (NFSIGNORE_SOERROR(nmp->nm_soflags, error))
1188 					so->so_error = 0;
1189 			} else {
1190 				/*
1191 				 * Iff first send, start timing
1192 				 * else turn timing off, backoff timer
1193 				 * and divide congestion window by 2.
1194 				 */
1195 				if (rep->r_flags & R_SENT) {
1196 					rep->r_flags &= ~R_TIMING;
1197 					if (++rep->r_rexmit > NFS_MAXREXMIT)
1198 						rep->r_rexmit = NFS_MAXREXMIT;
1199 					nmp->nm_cwnd >>= 1;
1200 					if (nmp->nm_cwnd < NFS_CWNDSCALE)
1201 						nmp->nm_cwnd = NFS_CWNDSCALE;
1202 					nfsstats.rpcretries++;
1203 				} else {
1204 					rep->r_flags |= R_SENT;
1205 					nmp->nm_sent += NFS_CWNDSCALE;
1206 				}
1207 				rep->r_rtt = 0;
1208 			}
1209 		}
1210 	}
1211 	NET_UNLOCK();
1212 	timeout_add(&nmp->nm_rtimeout, nfs_ticks);
1213 }
1214 
1215 /*
1216  * Test for a termination condition pending on the process.
1217  * This is used for NFSMNT_INT mounts.
1218  */
1219 int
1220 nfs_sigintr(struct nfsmount *nmp, struct nfsreq *rep, struct proc *p)
1221 {
1222 
1223 	if (rep && (rep->r_flags & R_SOFTTERM))
1224 		return (EINTR);
1225 	if (!(nmp->nm_flag & NFSMNT_INT))
1226 		return (0);
1227 	if (p && (SIGPENDING(p) & ~p->p_p->ps_sigacts->ps_sigignore &
1228 	    NFSINT_SIGMASK))
1229 		return (EINTR);
1230 	return (0);
1231 }
1232 
1233 /*
1234  * Lock a socket against others.
1235  * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
1236  * and also to avoid race conditions between the processes with nfs requests
1237  * in progress when a reconnect is necessary.
1238  */
1239 int
1240 nfs_sndlock(int *flagp, struct nfsreq *rep)
1241 {
1242 	uint64_t slptimeo = INFSLP;
1243 	struct proc *p;
1244 	int slpflag = 0;
1245 
1246 	if (rep) {
1247 		p = rep->r_procp;
1248 		if (rep->r_nmp->nm_flag & NFSMNT_INT)
1249 			slpflag = PCATCH;
1250 	} else
1251 		p = NULL;
1252 	while (*flagp & NFSMNT_SNDLOCK) {
1253 		if (rep && nfs_sigintr(rep->r_nmp, rep, p))
1254 			return (EINTR);
1255 		*flagp |= NFSMNT_WANTSND;
1256 		tsleep_nsec(flagp, slpflag | (PZERO - 1), "nfsndlck", slptimeo);
1257 		if (slpflag == PCATCH) {
1258 			slpflag = 0;
1259 			slptimeo = SEC_TO_NSEC(2);
1260 		}
1261 	}
1262 	*flagp |= NFSMNT_SNDLOCK;
1263 	return (0);
1264 }
1265 
1266 /*
1267  * Unlock the stream socket for others.
1268  */
1269 void
1270 nfs_sndunlock(int *flagp)
1271 {
1272 
1273 	if ((*flagp & NFSMNT_SNDLOCK) == 0)
1274 		panic("nfs sndunlock");
1275 	*flagp &= ~NFSMNT_SNDLOCK;
1276 	if (*flagp & NFSMNT_WANTSND) {
1277 		*flagp &= ~NFSMNT_WANTSND;
1278 		wakeup((caddr_t)flagp);
1279 	}
1280 }
1281 
1282 int
1283 nfs_rcvlock(struct nfsreq *rep)
1284 {
1285 	uint64_t slptimeo = INFSLP;
1286 	int *flagp = &rep->r_nmp->nm_flag;
1287 	int slpflag;
1288 
1289 	if (*flagp & NFSMNT_INT)
1290 		slpflag = PCATCH;
1291 	else
1292 		slpflag = 0;
1293 
1294 	while (*flagp & NFSMNT_RCVLOCK) {
1295 		if (nfs_sigintr(rep->r_nmp, rep, rep->r_procp))
1296 			return (EINTR);
1297 		*flagp |= NFSMNT_WANTRCV;
1298 		tsleep_nsec(flagp, slpflag | (PZERO - 1), "nfsrcvlk", slptimeo);
1299 		if (rep->r_mrep != NULL) {
1300 			/*
1301 			 * Don't take the lock if our reply has been received
1302 			 * while we where sleeping.
1303 			 */
1304 			 return (EALREADY);
1305 		}
1306 		if (slpflag == PCATCH) {
1307 			slpflag = 0;
1308 			slptimeo = SEC_TO_NSEC(2);
1309 		}
1310 	}
1311 	*flagp |= NFSMNT_RCVLOCK;
1312 	return (0);
1313 }
1314 
1315 /*
1316  * Unlock the stream socket for others.
1317  */
1318 void
1319 nfs_rcvunlock(int *flagp)
1320 {
1321 
1322 	if ((*flagp & NFSMNT_RCVLOCK) == 0)
1323 		panic("nfs rcvunlock");
1324 	*flagp &= ~NFSMNT_RCVLOCK;
1325 	if (*flagp & NFSMNT_WANTRCV) {
1326 		*flagp &= ~NFSMNT_WANTRCV;
1327 		wakeup(flagp);
1328 	}
1329 }
1330 
1331 /*
1332  * Auxiliary routine to align the length of mbuf copies made with m_copyback().
1333  */
1334 void
1335 nfs_realign_fixup(struct mbuf *m, struct mbuf *n, unsigned int *off)
1336 {
1337 	size_t padding;
1338 
1339 	/*
1340 	 * The maximum number of bytes that m_copyback() places in a mbuf is
1341 	 * always an aligned quantity, so realign happens at the chain's tail.
1342 	 */
1343 	while (n->m_next != NULL)
1344 		n = n->m_next;
1345 
1346 	/*
1347 	 * Pad from the next elements in the source chain. Loop until the
1348 	 * destination chain is aligned, or the end of the source is reached.
1349 	 */
1350 	do {
1351 		m = m->m_next;
1352 		if (m == NULL)
1353 			return;
1354 
1355 		padding = min(ALIGN(n->m_len) - n->m_len, m->m_len);
1356 		if (padding > m_trailingspace(n))
1357 			panic("nfs_realign_fixup: no memory to pad to");
1358 
1359 		bcopy(mtod(m, void *), mtod(n, char *) + n->m_len, padding);
1360 
1361 		n->m_len += padding;
1362 		m_adj(m, padding);
1363 		*off += padding;
1364 
1365 	} while (!ALIGNED_POINTER(n->m_len, void *));
1366 }
1367 
1368 /*
1369  * The NFS RPC parsing code uses the data address and the length of mbuf
1370  * structures to calculate on-memory addresses. This function makes sure these
1371  * parameters are correctly aligned.
1372  */
1373 void
1374 nfs_realign(struct mbuf **pm, int hsiz)
1375 {
1376 	struct mbuf *m;
1377 	struct mbuf *n = NULL;
1378 	unsigned int off = 0;
1379 
1380 	++nfs_realign_test;
1381 	while ((m = *pm) != NULL) {
1382 		if (!ALIGNED_POINTER(m->m_data, void *) ||
1383 		    !ALIGNED_POINTER(m->m_len,  void *)) {
1384 			MGET(n, M_WAIT, MT_DATA);
1385 #define ALIGN_POINTER(n) ((u_int)(((n) + sizeof(void *)) & ~sizeof(void *)))
1386 			if (ALIGN_POINTER(m->m_len) >= MINCLSIZE) {
1387 				MCLGET(n, M_WAIT);
1388 			}
1389 			n->m_len = 0;
1390 			break;
1391 		}
1392 		pm = &m->m_next;
1393 	}
1394 	/*
1395 	 * If n is non-NULL, loop on m copying data, then replace the
1396 	 * portion of the chain that had to be realigned.
1397 	 */
1398 	if (n != NULL) {
1399 		++nfs_realign_count;
1400 		while (m) {
1401 			m_copyback(n, off, m->m_len, mtod(m, caddr_t), M_WAIT);
1402 
1403 			/*
1404 			 * If an unaligned amount of memory was copied, fix up
1405 			 * the last mbuf created by m_copyback().
1406 			 */
1407 			if (!ALIGNED_POINTER(m->m_len, void *))
1408 				nfs_realign_fixup(m, n, &off);
1409 
1410 			off += m->m_len;
1411 			m = m->m_next;
1412 		}
1413 		m_freemp(pm);
1414 		*pm = n;
1415 	}
1416 }
1417 
1418 
1419 /*
1420  * Parse an RPC request
1421  * - verify it
1422  * - fill in the cred struct.
1423  */
1424 int
1425 nfs_getreq(struct nfsrv_descript *nd, struct nfsd *nfsd, int has_header)
1426 {
1427 	int len, i;
1428 	u_int32_t *tl;
1429 	int32_t t1;
1430 	caddr_t cp2;
1431 	u_int32_t nfsvers, auth_type;
1432 	int error = 0;
1433 	struct nfsm_info info;
1434 
1435 	info.nmi_mrep = nd->nd_mrep;
1436 	info.nmi_md = nd->nd_md;
1437 	info.nmi_dpos = nd->nd_dpos;
1438 	if (has_header) {
1439 		nfsm_dissect(tl, u_int32_t *, 10 * NFSX_UNSIGNED);
1440 		nd->nd_retxid = fxdr_unsigned(u_int32_t, *tl++);
1441 		if (*tl++ != rpc_call) {
1442 			m_freem(info.nmi_mrep);
1443 			return (EBADRPC);
1444 		}
1445 	} else
1446 		nfsm_dissect(tl, u_int32_t *, 8 * NFSX_UNSIGNED);
1447 	nd->nd_repstat = 0;
1448 	nd->nd_flag = 0;
1449 	if (*tl++ != rpc_vers) {
1450 		nd->nd_repstat = ERPCMISMATCH;
1451 		nd->nd_procnum = NFSPROC_NOOP;
1452 		return (0);
1453 	}
1454 	if (*tl != nfs_prog) {
1455 		nd->nd_repstat = EPROGUNAVAIL;
1456 		nd->nd_procnum = NFSPROC_NOOP;
1457 		return (0);
1458 	}
1459 	tl++;
1460 	nfsvers = fxdr_unsigned(u_int32_t, *tl++);
1461 	if (nfsvers != NFS_VER2 && nfsvers != NFS_VER3) {
1462 		nd->nd_repstat = EPROGMISMATCH;
1463 		nd->nd_procnum = NFSPROC_NOOP;
1464 		return (0);
1465 	}
1466 	if (nfsvers == NFS_VER3)
1467 		nd->nd_flag = ND_NFSV3;
1468 	nd->nd_procnum = fxdr_unsigned(u_int32_t, *tl++);
1469 	if (nd->nd_procnum == NFSPROC_NULL)
1470 		return (0);
1471 	if (nd->nd_procnum >= NFS_NPROCS ||
1472 		(nd->nd_procnum > NFSPROC_COMMIT) ||
1473 		(!nd->nd_flag && nd->nd_procnum > NFSV2PROC_STATFS)) {
1474 		nd->nd_repstat = EPROCUNAVAIL;
1475 		nd->nd_procnum = NFSPROC_NOOP;
1476 		return (0);
1477 	}
1478 	if ((nd->nd_flag & ND_NFSV3) == 0)
1479 		nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
1480 	auth_type = *tl++;
1481 	len = fxdr_unsigned(int, *tl++);
1482 	if (len < 0 || len > RPCAUTH_MAXSIZ) {
1483 		m_freem(info.nmi_mrep);
1484 		return (EBADRPC);
1485 	}
1486 
1487 	/* Handle auth_unix */
1488 	if (auth_type == rpc_auth_unix) {
1489 		len = fxdr_unsigned(int, *++tl);
1490 		if (len < 0 || len > NFS_MAXNAMLEN) {
1491 			m_freem(info.nmi_mrep);
1492 			return (EBADRPC);
1493 		}
1494 		nfsm_adv(nfsm_rndup(len));
1495 		nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
1496 		memset(&nd->nd_cr, 0, sizeof (struct ucred));
1497 		nd->nd_cr.cr_ref = 1;
1498 		nd->nd_cr.cr_uid = fxdr_unsigned(uid_t, *tl++);
1499 		nd->nd_cr.cr_gid = fxdr_unsigned(gid_t, *tl++);
1500 		len = fxdr_unsigned(int, *tl);
1501 		if (len < 0 || len > RPCAUTH_UNIXGIDS) {
1502 			m_freem(info.nmi_mrep);
1503 			return (EBADRPC);
1504 		}
1505 		nfsm_dissect(tl, u_int32_t *, (len + 2) * NFSX_UNSIGNED);
1506 		for (i = 0; i < len; i++) {
1507 			if (i < NGROUPS_MAX)
1508 				nd->nd_cr.cr_groups[i] =
1509 				    fxdr_unsigned(gid_t, *tl++);
1510 			else
1511 				tl++;
1512 		}
1513 		nd->nd_cr.cr_ngroups = (len > NGROUPS_MAX) ? NGROUPS_MAX : len;
1514 		len = fxdr_unsigned(int, *++tl);
1515 		if (len < 0 || len > RPCAUTH_MAXSIZ) {
1516 			m_freem(info.nmi_mrep);
1517 			return (EBADRPC);
1518 		}
1519 		if (len > 0)
1520 			nfsm_adv(nfsm_rndup(len));
1521 	} else {
1522 		nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
1523 		nd->nd_procnum = NFSPROC_NOOP;
1524 		return (0);
1525 	}
1526 
1527 	nd->nd_md = info.nmi_md;
1528 	nd->nd_dpos = info.nmi_dpos;
1529 	return (0);
1530 nfsmout:
1531 	return (error);
1532 }
1533 
1534 void
1535 nfs_msg(struct nfsreq *rep, char *msg)
1536 {
1537 	tpr_t tpr;
1538 
1539 	if (rep->r_procp)
1540 		tpr = tprintf_open(rep->r_procp);
1541 	else
1542 		tpr = NULL;
1543 
1544 	tprintf(tpr, "nfs server %s: %s\n",
1545 	    rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname, msg);
1546 	tprintf_close(tpr);
1547 }
1548 
1549 #ifdef NFSSERVER
1550 /*
1551  * Socket upcall routine for the nfsd sockets.
1552  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
1553  * Essentially do as much as possible non-blocking, else punt and it will
1554  * be called with M_WAIT from an nfsd.
1555  */
1556 void
1557 nfsrv_rcv(struct socket *so, caddr_t arg, int waitflag)
1558 {
1559 	struct nfssvc_sock *slp = (struct nfssvc_sock *)arg;
1560 	struct mbuf *m;
1561 	struct mbuf *mp, *nam;
1562 	struct uio auio;
1563 	int flags, error;
1564 
1565 	if ((slp->ns_flag & SLP_VALID) == 0)
1566 		return;
1567 
1568 	/* Defer soreceive() to an nfsd. */
1569 	if (waitflag == M_DONTWAIT) {
1570 		slp->ns_flag |= SLP_NEEDQ;
1571 		goto dorecs;
1572 	}
1573 
1574 	auio.uio_procp = NULL;
1575 	if (so->so_type == SOCK_STREAM) {
1576 		/*
1577 		 * Do soreceive().
1578 		 */
1579 		auio.uio_resid = 1000000000;
1580 		flags = MSG_DONTWAIT;
1581 		error = soreceive(so, &nam, &auio, &mp, NULL,
1582 		    &flags, 0);
1583 		if (error || mp == NULL) {
1584 			if (error == EWOULDBLOCK)
1585 				slp->ns_flag |= SLP_NEEDQ;
1586 			else
1587 				slp->ns_flag |= SLP_DISCONN;
1588 			goto dorecs;
1589 		}
1590 		m = mp;
1591 		if (slp->ns_rawend) {
1592 			slp->ns_rawend->m_next = m;
1593 			slp->ns_cc += 1000000000 - auio.uio_resid;
1594 		} else {
1595 			slp->ns_raw = m;
1596 			slp->ns_cc = 1000000000 - auio.uio_resid;
1597 		}
1598 		while (m->m_next)
1599 			m = m->m_next;
1600 		slp->ns_rawend = m;
1601 
1602 		/*
1603 		 * Now try and parse record(s) out of the raw stream data.
1604 		 */
1605 		error = nfsrv_getstream(slp, waitflag);
1606 		if (error) {
1607 			if (error == EPERM)
1608 				slp->ns_flag |= SLP_DISCONN;
1609 			else
1610 				slp->ns_flag |= SLP_NEEDQ;
1611 		}
1612 	} else {
1613 		do {
1614 			auio.uio_resid = 1000000000;
1615 			flags = MSG_DONTWAIT;
1616 			error = soreceive(so, &nam, &auio, &mp,
1617 			    NULL, &flags, 0);
1618 			if (mp) {
1619 				if (nam) {
1620 					m = nam;
1621 					m->m_next = mp;
1622 				} else
1623 					m = mp;
1624 				if (slp->ns_recend)
1625 					slp->ns_recend->m_nextpkt = m;
1626 				else
1627 					slp->ns_rec = m;
1628 				slp->ns_recend = m;
1629 				m->m_nextpkt = NULL;
1630 			}
1631 			if (error) {
1632 				if ((so->so_proto->pr_flags & PR_CONNREQUIRED)
1633 					&& error != EWOULDBLOCK) {
1634 					slp->ns_flag |= SLP_DISCONN;
1635 					goto dorecs;
1636 				}
1637 			}
1638 		} while (mp);
1639 	}
1640 
1641 	/*
1642 	 * Now try and process the request records, non-blocking.
1643 	 */
1644 dorecs:
1645 	if (waitflag == M_DONTWAIT &&
1646 		(slp->ns_rec || (slp->ns_flag & (SLP_NEEDQ | SLP_DISCONN))))
1647 		nfsrv_wakenfsd(slp);
1648 }
1649 
1650 /*
1651  * Try and extract an RPC request from the mbuf data list received on a
1652  * stream socket. The "waitflag" argument indicates whether or not it
1653  * can sleep.
1654  */
1655 int
1656 nfsrv_getstream(struct nfssvc_sock *slp, int waitflag)
1657 {
1658 	struct mbuf *m, **mpp;
1659 	char *cp1, *cp2;
1660 	int len;
1661 	struct mbuf *om, *m2, *recm;
1662 	u_int32_t recmark;
1663 
1664 	if (slp->ns_flag & SLP_GETSTREAM)
1665 		return (0);
1666 	slp->ns_flag |= SLP_GETSTREAM;
1667 	for (;;) {
1668 		if (slp->ns_reclen == 0) {
1669 			if (slp->ns_cc < NFSX_UNSIGNED) {
1670 				slp->ns_flag &= ~SLP_GETSTREAM;
1671 				return (0);
1672 			}
1673 			m = slp->ns_raw;
1674 			if (m->m_len >= NFSX_UNSIGNED) {
1675 				bcopy(mtod(m, caddr_t), &recmark,
1676 				    NFSX_UNSIGNED);
1677 				m->m_data += NFSX_UNSIGNED;
1678 				m->m_len -= NFSX_UNSIGNED;
1679 			} else {
1680 				cp1 = (caddr_t)&recmark;
1681 				cp2 = mtod(m, caddr_t);
1682 				while (cp1 < ((caddr_t)&recmark) + NFSX_UNSIGNED) {
1683 					while (m->m_len == 0) {
1684 						m = m->m_next;
1685 						cp2 = mtod(m, caddr_t);
1686 					}
1687 					*cp1++ = *cp2++;
1688 					m->m_data++;
1689 					m->m_len--;
1690 				}
1691 			}
1692 			slp->ns_cc -= NFSX_UNSIGNED;
1693 			recmark = ntohl(recmark);
1694 			slp->ns_reclen = recmark & ~0x80000000;
1695 			if (recmark & 0x80000000)
1696 				slp->ns_flag |= SLP_LASTFRAG;
1697 			else
1698 				slp->ns_flag &= ~SLP_LASTFRAG;
1699 			if (slp->ns_reclen > NFS_MAXPACKET) {
1700 				slp->ns_flag &= ~SLP_GETSTREAM;
1701 				return (EPERM);
1702 			}
1703 		}
1704 
1705 		/*
1706 		 * Now get the record part.
1707 		 */
1708 		recm = NULL;
1709 		if (slp->ns_cc == slp->ns_reclen) {
1710 			recm = slp->ns_raw;
1711 			slp->ns_raw = slp->ns_rawend = NULL;
1712 			slp->ns_cc = slp->ns_reclen = 0;
1713 		} else if (slp->ns_cc > slp->ns_reclen) {
1714 			len = 0;
1715 			m = slp->ns_raw;
1716 			om = NULL;
1717 			while (len < slp->ns_reclen) {
1718 				if ((len + m->m_len) > slp->ns_reclen) {
1719 					m2 = m_copym(m, 0, slp->ns_reclen - len,
1720 					    waitflag);
1721 					if (m2) {
1722 						if (om) {
1723 							om->m_next = m2;
1724 							recm = slp->ns_raw;
1725 						} else
1726 							recm = m2;
1727 						m->m_data += slp->ns_reclen-len;
1728 						m->m_len -= slp->ns_reclen-len;
1729 						len = slp->ns_reclen;
1730 					} else {
1731 						slp->ns_flag &= ~SLP_GETSTREAM;
1732 						return (EWOULDBLOCK);
1733 					}
1734 				} else if ((len + m->m_len) == slp->ns_reclen) {
1735 					om = m;
1736 					len += m->m_len;
1737 					m = m->m_next;
1738 					recm = slp->ns_raw;
1739 					om->m_next = NULL;
1740 				} else {
1741 					om = m;
1742 					len += m->m_len;
1743 					m = m->m_next;
1744 				}
1745 			}
1746 			slp->ns_raw = m;
1747 			slp->ns_cc -= len;
1748 			slp->ns_reclen = 0;
1749 		} else {
1750 			slp->ns_flag &= ~SLP_GETSTREAM;
1751 			return (0);
1752 		}
1753 
1754 		/*
1755 		 * Accumulate the fragments into a record.
1756 		 */
1757 		mpp = &slp->ns_frag;
1758 		while (*mpp)
1759 			mpp = &((*mpp)->m_next);
1760 		*mpp = recm;
1761 		if (slp->ns_flag & SLP_LASTFRAG) {
1762 			if (slp->ns_recend)
1763 			    slp->ns_recend->m_nextpkt = slp->ns_frag;
1764 			else
1765 			    slp->ns_rec = slp->ns_frag;
1766 			slp->ns_recend = slp->ns_frag;
1767 			slp->ns_frag = NULL;
1768 		}
1769 	}
1770 }
1771 
1772 /*
1773  * Parse an RPC header.
1774  */
1775 int
1776 nfsrv_dorec(struct nfssvc_sock *slp, struct nfsd *nfsd,
1777     struct nfsrv_descript **ndp)
1778 {
1779 	struct mbuf *m, *nam;
1780 	struct nfsrv_descript *nd;
1781 	int error;
1782 
1783 	*ndp = NULL;
1784 	if ((slp->ns_flag & SLP_VALID) == 0 ||
1785 	    (m = slp->ns_rec) == NULL)
1786 		return (ENOBUFS);
1787 	slp->ns_rec = m->m_nextpkt;
1788 	if (slp->ns_rec)
1789 		m->m_nextpkt = NULL;
1790 	else
1791 		slp->ns_recend = NULL;
1792 	if (m->m_type == MT_SONAME) {
1793 		nam = m;
1794 		m = m->m_next;
1795 		nam->m_next = NULL;
1796 	} else
1797 		nam = NULL;
1798 	nd = pool_get(&nfsrv_descript_pl, PR_WAITOK);
1799 	nfs_realign(&m, 10 * NFSX_UNSIGNED);
1800 	nd->nd_md = nd->nd_mrep = m;
1801 	nd->nd_nam2 = nam;
1802 	nd->nd_dpos = mtod(m, caddr_t);
1803 	error = nfs_getreq(nd, nfsd, 1);
1804 	if (error) {
1805 		m_freem(nam);
1806 		pool_put(&nfsrv_descript_pl, nd);
1807 		return (error);
1808 	}
1809 	*ndp = nd;
1810 	nfsd->nfsd_nd = nd;
1811 	return (0);
1812 }
1813 
1814 
1815 /*
1816  * Search for a sleeping nfsd and wake it up.
1817  * SIDE EFFECT: If none found, set NFSD_CHECKSLP flag, so that one of the
1818  * running nfsds will go look for the work in the nfssvc_sock list.
1819  */
1820 void
1821 nfsrv_wakenfsd(struct nfssvc_sock *slp)
1822 {
1823 	struct nfsd	*nfsd;
1824 
1825 	if ((slp->ns_flag & SLP_VALID) == 0)
1826 		return;
1827 
1828 	TAILQ_FOREACH(nfsd, &nfsd_head, nfsd_chain) {
1829 		if (nfsd->nfsd_flag & NFSD_WAITING) {
1830 			nfsd->nfsd_flag &= ~NFSD_WAITING;
1831 			if (nfsd->nfsd_slp)
1832 				panic("nfsd wakeup");
1833 			slp->ns_sref++;
1834 			nfsd->nfsd_slp = slp;
1835 			wakeup_one(nfsd);
1836 			return;
1837 		}
1838 	}
1839 
1840 	slp->ns_flag |= SLP_DOREC;
1841 	nfsd_head_flag |= NFSD_CHECKSLP;
1842 }
1843 #endif /* NFSSERVER */
1844