xref: /openbsd-src/sys/nfs/nfs_socket.c (revision ae3cb403620ab940fbaabb3055fac045a63d56b7)
1 /*	$OpenBSD: nfs_socket.c,v 1.128 2017/09/07 11:35:34 bluhm 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(so, &so->so_timeo, PSOCK, "nfscon", 2 * hz);
319 			if ((so->so_state & SS_ISCONNECTING) &&
320 			    so->so_error == 0 && rep &&
321 			    (error = nfs_sigintr(nmp, rep, rep->r_procp)) != 0){
322 				so->so_state &= ~SS_ISCONNECTING;
323 				goto bad;
324 			}
325 		}
326 		if (so->so_error) {
327 			error = so->so_error;
328 			so->so_error = 0;
329 			goto bad;
330 		}
331 	}
332 	/*
333 	 * Always set receive timeout to detect server crash and reconnect.
334 	 * Otherwise, we can get stuck in soreceive forever.
335 	 */
336 	so->so_rcv.sb_timeo = (5 * hz);
337 	if (nmp->nm_flag & (NFSMNT_SOFT | NFSMNT_INT))
338 		so->so_snd.sb_timeo = (5 * hz);
339 	else
340 		so->so_snd.sb_timeo = 0;
341 	if (nmp->nm_sotype == SOCK_DGRAM) {
342 		sndreserve = nmp->nm_wsize + NFS_MAXPKTHDR;
343 		rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
344 		    NFS_MAXPKTHDR) * 2;
345 	} else if (nmp->nm_sotype == SOCK_STREAM) {
346 		if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
347 			*mtod(mopt, int32_t *) = 1;
348 			mopt->m_len = sizeof(int32_t);
349 			sosetopt(so, SOL_SOCKET, SO_KEEPALIVE, mopt);
350 		}
351 		if (so->so_proto->pr_protocol == IPPROTO_TCP) {
352 			*mtod(mopt, int32_t *) = 1;
353 			mopt->m_len = sizeof(int32_t);
354 			sosetopt(so, IPPROTO_TCP, TCP_NODELAY, mopt);
355 		}
356 		sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR +
357 		    sizeof (u_int32_t)) * 2;
358 		rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR +
359 		    sizeof (u_int32_t)) * 2;
360 	} else {
361 		panic("%s: nm_sotype %d", __func__, nmp->nm_sotype);
362 	}
363 	error = soreserve(so, sndreserve, rcvreserve);
364 	if (error)
365 		goto bad;
366 	so->so_rcv.sb_flags |= SB_NOINTR;
367 	so->so_snd.sb_flags |= SB_NOINTR;
368 	sounlock(s);
369 
370 	m_freem(mopt);
371 	m_freem(nam);
372 
373 	/* Initialize other non-zero congestion variables */
374 	nfs_init_rtt(nmp);
375 	nmp->nm_cwnd = NFS_MAXCWND / 2;	    /* Initial send window */
376 	nmp->nm_sent = 0;
377 	nmp->nm_timeouts = 0;
378 	return (0);
379 
380 bad:
381 	sounlock(s);
382 
383 	m_freem(mopt);
384 	m_freem(nam);
385 
386 	nfs_disconnect(nmp);
387 	return (error);
388 }
389 
390 /*
391  * Reconnect routine:
392  * Called when a connection is broken on a reliable protocol.
393  * - clean up the old socket
394  * - nfs_connect() again
395  * - set R_MUSTRESEND for all outstanding requests on mount point
396  * If this fails the mount point is DEAD!
397  * nb: Must be called with the nfs_sndlock() set on the mount point.
398  */
399 int
400 nfs_reconnect(struct nfsreq *rep)
401 {
402 	struct nfsreq *rp;
403 	struct nfsmount *nmp = rep->r_nmp;
404 	int error;
405 
406 	nfs_disconnect(nmp);
407 	while ((error = nfs_connect(nmp, rep)) != 0) {
408 		if (error == EINTR || error == ERESTART)
409 			return (EINTR);
410 		(void)tsleep((caddr_t)&lbolt, PSOCK, "nfsrecon", 0);
411 	}
412 
413 	/*
414 	 * Loop through outstanding request list and fix up all requests
415 	 * on old socket.
416 	 */
417 	TAILQ_FOREACH(rp, &nmp->nm_reqsq, r_chain) {
418 		rp->r_flags |= R_MUSTRESEND;
419 		rp->r_rexmit = 0;
420 	}
421 	return (0);
422 }
423 
424 /*
425  * NFS disconnect. Clean up and unlink.
426  */
427 void
428 nfs_disconnect(struct nfsmount *nmp)
429 {
430 	struct socket *so;
431 
432 	if (nmp->nm_so) {
433 		so = nmp->nm_so;
434 		nmp->nm_so = NULL;
435 		soshutdown(so, SHUT_RDWR);
436 		soclose(so);
437 	}
438 }
439 
440 /*
441  * This is the nfs send routine. For connection based socket types, it
442  * must be called with an nfs_sndlock() on the socket.
443  * "rep == NULL" indicates that it has been called from a server.
444  * For the client side:
445  * - return EINTR if the RPC is terminated, 0 otherwise
446  * - set R_MUSTRESEND if the send fails for any reason
447  * - do any cleanup required by recoverable socket errors (???)
448  * For the server side:
449  * - return EINTR or ERESTART if interrupted by a signal
450  * - return EPIPE if a connection is lost for connection based sockets (TCP...)
451  * - do any cleanup required by recoverable socket errors (???)
452  */
453 int
454 nfs_send(struct socket *so, struct mbuf *nam, struct mbuf *top,
455     struct nfsreq *rep)
456 {
457 	struct mbuf *sendnam;
458 	int error, soflags, flags;
459 
460 	if (rep) {
461 		if (rep->r_flags & R_SOFTTERM) {
462 			m_freem(top);
463 			return (EINTR);
464 		}
465 		if ((so = rep->r_nmp->nm_so) == NULL) {
466 			rep->r_flags |= R_MUSTRESEND;
467 			m_freem(top);
468 			return (0);
469 		}
470 		rep->r_flags &= ~R_MUSTRESEND;
471 		soflags = rep->r_nmp->nm_soflags;
472 	} else
473 		soflags = so->so_proto->pr_flags;
474 	if ((soflags & PR_CONNREQUIRED) || (so->so_state & SS_ISCONNECTED))
475 		sendnam = NULL;
476 	else
477 		sendnam = nam;
478 	flags = 0;
479 
480 	error = sosend(so, sendnam, NULL, top, NULL, flags);
481 	if (error) {
482 		if (rep) {
483 			/*
484 			 * Deal with errors for the client side.
485 			 */
486 			if (rep->r_flags & R_SOFTTERM)
487 				error = EINTR;
488 			else
489 				rep->r_flags |= R_MUSTRESEND;
490 		}
491 
492 		/*
493 		 * Handle any recoverable (soft) socket errors here. (???)
494 		 */
495 		if (error != EINTR && error != ERESTART &&
496 		    error != EWOULDBLOCK && error != EPIPE)
497 			error = 0;
498 	}
499 	return (error);
500 }
501 
502 #ifdef NFSCLIENT
503 /*
504  * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
505  * done by soreceive(), but for SOCK_STREAM we must deal with the Record
506  * Mark and consolidate the data into a new mbuf list.
507  * nb: Sometimes TCP passes the data up to soreceive() in long lists of
508  *     small mbufs.
509  * For SOCK_STREAM we must be very careful to read an entire record once
510  * we have read any of it, even if the system call has been interrupted.
511  */
512 int
513 nfs_receive(struct nfsreq *rep, struct mbuf **aname, struct mbuf **mp)
514 {
515 	struct socket *so;
516 	struct uio auio;
517 	struct iovec aio;
518 	struct mbuf *m;
519 	struct mbuf *control;
520 	u_int32_t len;
521 	struct mbuf **getnam;
522 	int error, sotype, rcvflg;
523 	struct proc *p = curproc;	/* XXX */
524 
525 	/*
526 	 * Set up arguments for soreceive()
527 	 */
528 	*mp = NULL;
529 	*aname = NULL;
530 	sotype = rep->r_nmp->nm_sotype;
531 
532 	/*
533 	 * For reliable protocols, lock against other senders/receivers
534 	 * in case a reconnect is necessary.
535 	 * For SOCK_STREAM, first get the Record Mark to find out how much
536 	 * more there is to get.
537 	 * We must lock the socket against other receivers
538 	 * until we have an entire rpc request/reply.
539 	 */
540 	if (sotype != SOCK_DGRAM) {
541 		error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
542 		if (error)
543 			return (error);
544 tryagain:
545 		/*
546 		 * Check for fatal errors and resending request.
547 		 */
548 		/*
549 		 * Ugh: If a reconnect attempt just happened, nm_so
550 		 * would have changed. NULL indicates a failed
551 		 * attempt that has essentially shut down this
552 		 * mount point.
553 		 */
554 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
555 			nfs_sndunlock(&rep->r_nmp->nm_flag);
556 			return (EINTR);
557 		}
558 		so = rep->r_nmp->nm_so;
559 		if (!so) {
560 			error = nfs_reconnect(rep);
561 			if (error) {
562 				nfs_sndunlock(&rep->r_nmp->nm_flag);
563 				return (error);
564 			}
565 			goto tryagain;
566 		}
567 		while (rep->r_flags & R_MUSTRESEND) {
568 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
569 			nfsstats.rpcretries++;
570 			rep->r_rtt = 0;
571 			rep->r_flags &= ~R_TIMING;
572 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
573 			if (error) {
574 				if (error == EINTR || error == ERESTART ||
575 				    (error = nfs_reconnect(rep)) != 0) {
576 					nfs_sndunlock(&rep->r_nmp->nm_flag);
577 					return (error);
578 				}
579 				goto tryagain;
580 			}
581 		}
582 		nfs_sndunlock(&rep->r_nmp->nm_flag);
583 		if (sotype == SOCK_STREAM) {
584 			aio.iov_base = (caddr_t) &len;
585 			aio.iov_len = sizeof(u_int32_t);
586 			auio.uio_iov = &aio;
587 			auio.uio_iovcnt = 1;
588 			auio.uio_segflg = UIO_SYSSPACE;
589 			auio.uio_rw = UIO_READ;
590 			auio.uio_offset = 0;
591 			auio.uio_resid = sizeof(u_int32_t);
592 			auio.uio_procp = p;
593 			do {
594 				rcvflg = MSG_WAITALL;
595 				error = soreceive(so, NULL, &auio, NULL, NULL,
596 				    &rcvflg, 0);
597 				if (error == EWOULDBLOCK && rep) {
598 					if (rep->r_flags & R_SOFTTERM)
599 						return (EINTR);
600 					/*
601 					 * looks like the server died after it
602 					 * received the request, make sure
603 					 * that we will retransmit and we
604 					 * don't get stuck here forever.
605 					 */
606 					if (rep->r_rexmit >=
607 					    rep->r_nmp->nm_retry) {
608 						nfsstats.rpctimeouts++;
609 						error = EPIPE;
610 					}
611 				}
612 			} while (error == EWOULDBLOCK);
613 			if (!error && auio.uio_resid > 0) {
614 			    log(LOG_INFO,
615 				 "short receive (%zu/%zu) from nfs server %s\n",
616 				 sizeof(u_int32_t) - auio.uio_resid,
617 				 sizeof(u_int32_t),
618 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
619 			    error = EPIPE;
620 			}
621 			if (error)
622 				goto errout;
623 
624 			len = ntohl(len) & ~0x80000000;
625 			/*
626 			 * This is SERIOUS! We are out of sync with the sender
627 			 * and forcing a disconnect/reconnect is all I can do.
628 			 */
629 			if (len > NFS_MAXPACKET) {
630 			    log(LOG_ERR, "%s (%u) from nfs server %s\n",
631 				"impossible packet length",
632 				len,
633 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
634 			    error = EFBIG;
635 			    goto errout;
636 			}
637 			auio.uio_resid = len;
638 			do {
639 			    rcvflg = MSG_WAITALL;
640 			    error =  soreceive(so, NULL, &auio, mp, NULL,
641 			        &rcvflg, 0);
642 			} while (error == EWOULDBLOCK || error == EINTR ||
643 			    error == ERESTART);
644 			if (!error && auio.uio_resid > 0) {
645 				log(LOG_INFO, "short receive (%zu/%u) from "
646 				    "nfs server %s\n", len - auio.uio_resid,
647 				    len, rep->r_nmp->nm_mountp->
648 				    mnt_stat.f_mntfromname);
649 				error = EPIPE;
650 			}
651 		} else {
652 			/*
653 			 * NB: Since uio_resid is big, MSG_WAITALL is ignored
654 			 * and soreceive() will return when it has either a
655 			 * control msg or a data msg.
656 			 * We have no use for control msg., but must grab them
657 			 * and then throw them away so we know what is going
658 			 * on.
659 			 */
660 			auio.uio_resid = len = 100000000; /* Anything Big */
661 			auio.uio_procp = p;
662 			do {
663 				rcvflg = 0;
664 				error = soreceive(so, NULL, &auio, mp, &control,
665 				    &rcvflg, 0);
666 				m_freem(control);
667 				if (error == EWOULDBLOCK && rep) {
668 					if (rep->r_flags & R_SOFTTERM)
669 						return (EINTR);
670 				}
671 			} while (error == EWOULDBLOCK ||
672 			    (!error && *mp == NULL && control));
673 			if ((rcvflg & MSG_EOR) == 0)
674 				printf("Egad!!\n");
675 			if (!error && *mp == NULL)
676 				error = EPIPE;
677 			len -= auio.uio_resid;
678 		}
679 errout:
680 		if (error && error != EINTR && error != ERESTART) {
681 			m_freemp(mp);
682 			if (error != EPIPE)
683 				log(LOG_INFO,
684 				    "receive error %d from nfs server %s\n",
685 				    error,
686 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
687 			error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
688 			if (!error) {
689 				error = nfs_reconnect(rep);
690 				if (!error)
691 					goto tryagain;
692 				nfs_sndunlock(&rep->r_nmp->nm_flag);
693 			}
694 		}
695 	} else {
696 		if ((so = rep->r_nmp->nm_so) == NULL)
697 			return (EACCES);
698 		if (so->so_state & SS_ISCONNECTED)
699 			getnam = NULL;
700 		else
701 			getnam = aname;
702 		auio.uio_resid = len = 1000000;
703 		auio.uio_procp = p;
704 		do {
705 			rcvflg = 0;
706 			error = soreceive(so, getnam, &auio, mp, NULL,
707 			    &rcvflg, 0);
708 			if (error == EWOULDBLOCK &&
709 			    (rep->r_flags & R_SOFTTERM))
710 				return (EINTR);
711 		} while (error == EWOULDBLOCK);
712 		len -= auio.uio_resid;
713 	}
714 	if (error)
715 		m_freemp(mp);
716 	/*
717 	 * Search for any mbufs that are not a multiple of 4 bytes long
718 	 * or with m_data not longword aligned.
719 	 * These could cause pointer alignment problems, so copy them to
720 	 * well aligned mbufs.
721 	 */
722 	nfs_realign(mp, 5 * NFSX_UNSIGNED);
723 	return (error);
724 }
725 
726 /*
727  * Implement receipt of reply on a socket.
728  * We must search through the list of received datagrams matching them
729  * with outstanding requests using the xid, until ours is found.
730  */
731 int
732 nfs_reply(struct nfsreq *myrep)
733 {
734 	struct nfsreq *rep;
735 	struct nfsmount *nmp = myrep->r_nmp;
736 	struct nfsm_info	info;
737 	struct mbuf *nam;
738 	u_int32_t rxid, *tl, t1;
739 	caddr_t cp2;
740 	int error;
741 
742 	/*
743 	 * Loop around until we get our own reply
744 	 */
745 	for (;;) {
746 		/*
747 		 * Lock against other receivers so that I don't get stuck in
748 		 * sbwait() after someone else has received my reply for me.
749 		 * Also necessary for connection based protocols to avoid
750 		 * race conditions during a reconnect.
751 		 */
752 		error = nfs_rcvlock(myrep);
753 		if (error)
754 			return (error == EALREADY ? 0 : error);
755 
756 		/*
757 		 * Get the next Rpc reply off the socket
758 		 */
759 		error = nfs_receive(myrep, &nam, &info.nmi_mrep);
760 		nfs_rcvunlock(&nmp->nm_flag);
761 		if (error) {
762 
763 			/*
764 			 * Ignore routing errors on connectionless protocols??
765 			 */
766 			if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
767 				if (nmp->nm_so)
768 					nmp->nm_so->so_error = 0;
769 				continue;
770 			}
771 			return (error);
772 		}
773 		m_freem(nam);
774 
775 		/*
776 		 * Get the xid and check that it is an rpc reply
777 		 */
778 		info.nmi_md = info.nmi_mrep;
779 		info.nmi_dpos = mtod(info.nmi_md, caddr_t);
780 		nfsm_dissect(tl, u_int32_t *, 2 * NFSX_UNSIGNED);
781 		rxid = *tl++;
782 		if (*tl != rpc_reply) {
783 			nfsstats.rpcinvalid++;
784 			m_freem(info.nmi_mrep);
785 nfsmout:
786 			continue;
787 		}
788 
789 		/*
790 		 * Loop through the request list to match up the reply
791 		 * Iff no match, just drop the datagram
792 		 */
793 		TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
794 			if (rep->r_mrep == NULL && rxid == rep->r_xid) {
795 				/* Found it.. */
796 				rep->r_mrep = info.nmi_mrep;
797 				rep->r_md = info.nmi_md;
798 				rep->r_dpos = info.nmi_dpos;
799 
800 				/*
801 				 * Update congestion window.
802 				 * Do the additive increase of
803 				 * one rpc/rtt.
804 				 */
805 				if (nmp->nm_cwnd <= nmp->nm_sent) {
806 					nmp->nm_cwnd +=
807 					   (NFS_CWNDSCALE * NFS_CWNDSCALE +
808 					   (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
809 					if (nmp->nm_cwnd > NFS_MAXCWND)
810 						nmp->nm_cwnd = NFS_MAXCWND;
811 				}
812 				rep->r_flags &= ~R_SENT;
813 				nmp->nm_sent -= NFS_CWNDSCALE;
814 
815 				if (rep->r_flags & R_TIMING)
816 					nfs_update_rtt(rep);
817 
818 				nmp->nm_timeouts = 0;
819 				break;
820 			}
821 		}
822 		/*
823 		 * If not matched to a request, drop it.
824 		 * If it's mine, get out.
825 		 */
826 		if (rep == 0) {
827 			nfsstats.rpcunexpected++;
828 			m_freem(info.nmi_mrep);
829 		} else if (rep == myrep) {
830 			if (rep->r_mrep == NULL)
831 				panic("nfsreply nil");
832 			return (0);
833 		}
834 	}
835 }
836 
837 /*
838  * nfs_request - goes something like this
839  *	- fill in request struct
840  *	- links it into list
841  *	- calls nfs_send() for first transmit
842  *	- calls nfs_receive() to get reply
843  *	- break down rpc header and return with nfs reply pointed to
844  *	  by mrep or error
845  * nb: always frees up mreq mbuf list
846  */
847 int
848 nfs_request(struct vnode *vp, int procnum, struct nfsm_info *infop)
849 {
850 	struct mbuf *m;
851 	u_int32_t *tl;
852 	struct nfsmount *nmp;
853 	struct timeval tv;
854 	caddr_t cp2;
855 	int t1, i, error = 0;
856 	int trylater_delay;
857 	struct nfsreq *rep;
858 	int mrest_len;
859 	struct nfsm_info info;
860 
861 	rep = pool_get(&nfsreqpl, PR_WAITOK);
862 	rep->r_nmp = VFSTONFS(vp->v_mount);
863 	rep->r_vp = vp;
864 	rep->r_procp = infop->nmi_procp;
865 	rep->r_procnum = procnum;
866 
867 	mrest_len = 0;
868 	m = infop->nmi_mreq;
869 	while (m) {
870 		mrest_len += m->m_len;
871 		m = m->m_next;
872 	}
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_pkthdr.len = mrest_len;
878 
879 	trylater_delay = NFS_MINTIMEO;
880 
881 	nmp = rep->r_nmp;
882 
883 	/* Get the RPC header with authorization. */
884 	nfsm_rpchead(rep, infop->nmi_cred, RPCAUTH_UNIX);
885 	m = rep->r_mreq;
886 
887 	/*
888 	 * For stream protocols, insert a Sun RPC Record Mark.
889 	 */
890 	if (nmp->nm_sotype == SOCK_STREAM) {
891 		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
892 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
893 		    (m->m_pkthdr.len - NFSX_UNSIGNED));
894 	}
895 
896 tryagain:
897 	rep->r_rtt = rep->r_rexmit = 0;
898 	if (nfs_ptimers[rep->r_procnum] != NFS_DEFAULT_TIMER)
899 		rep->r_flags = R_TIMING;
900 	else
901 		rep->r_flags = 0;
902 	rep->r_mrep = NULL;
903 
904 	/*
905 	 * Do the client side RPC.
906 	 */
907 	nfsstats.rpcrequests++;
908 	/*
909 	 * Chain request into list of outstanding requests. Be sure
910 	 * to put it LAST so timer finds oldest requests first.
911 	 */
912 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
913 		timeout_add(&nmp->nm_rtimeout, nfs_ticks);
914 	TAILQ_INSERT_TAIL(&nmp->nm_reqsq, rep, r_chain);
915 
916 	/*
917 	 * If backing off another request or avoiding congestion, don't
918 	 * send this one now but let timer do it. If not timing a request,
919 	 * do it now.
920 	 */
921 	if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
922 		(nmp->nm_flag & NFSMNT_DUMBTIMR) ||
923 		nmp->nm_sent < nmp->nm_cwnd)) {
924 		if (nmp->nm_soflags & PR_CONNREQUIRED)
925 			error = nfs_sndlock(&nmp->nm_flag, rep);
926 		if (!error) {
927 			error = nfs_send(nmp->nm_so, nmp->nm_nam,
928 			    m_copym(m, 0, M_COPYALL, M_WAIT), rep);
929 			if (nmp->nm_soflags & PR_CONNREQUIRED)
930 				nfs_sndunlock(&nmp->nm_flag);
931 		}
932 		if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
933 			nmp->nm_sent += NFS_CWNDSCALE;
934 			rep->r_flags |= R_SENT;
935 		}
936 	} else {
937 		rep->r_rtt = -1;
938 	}
939 
940 	/*
941 	 * Wait for the reply from our send or the timer's.
942 	 */
943 	if (!error || error == EPIPE)
944 		error = nfs_reply(rep);
945 
946 	/*
947 	 * RPC done, unlink the request.
948 	 */
949 	TAILQ_REMOVE(&nmp->nm_reqsq, rep, r_chain);
950 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
951 		timeout_del(&nmp->nm_rtimeout);
952 
953 	/*
954 	 * Decrement the outstanding request count.
955 	 */
956 	if (rep->r_flags & R_SENT) {
957 		rep->r_flags &= ~R_SENT;	/* paranoia */
958 		nmp->nm_sent -= NFS_CWNDSCALE;
959 	}
960 
961 	/*
962 	 * If there was a successful reply and a tprintf msg.
963 	 * tprintf a response.
964 	 */
965 	if (!error && (rep->r_flags & R_TPRINTFMSG))
966 		nfs_msg(rep, "is alive again");
967 	info.nmi_mrep = rep->r_mrep;
968 	info.nmi_md = rep->r_md;
969 	info.nmi_dpos = rep->r_dpos;
970 	if (error) {
971 		infop->nmi_mrep = NULL;
972 		goto nfsmout1;
973 	}
974 
975 	/*
976 	 * break down the rpc header and check if ok
977 	 */
978 	nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
979 	if (*tl++ == rpc_msgdenied) {
980 		if (*tl == rpc_mismatch)
981 			error = EOPNOTSUPP;
982 		else
983 			error = EACCES;	/* Should be EAUTH. */
984 		infop->nmi_mrep = NULL;
985 		goto nfsmout1;
986 	}
987 
988 	/*
989 	 * Since we only support RPCAUTH_UNIX atm we step over the
990 	 * reply verifer type, and in the (error) case that there really
991 	 * is any data in it, we advance over it.
992 	 */
993 	tl++;			/* Step over verifer type */
994 	i = fxdr_unsigned(int32_t, *tl);
995 	if (i > 0)
996 		nfsm_adv(nfsm_rndup(i));	/* Should not happen */
997 
998 	nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
999 	/* 0 == ok */
1000 	if (*tl == 0) {
1001 		nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
1002 		if (*tl != 0) {
1003 			error = fxdr_unsigned(int, *tl);
1004 			if ((nmp->nm_flag & NFSMNT_NFSV3) &&
1005 			    error == NFSERR_TRYLATER) {
1006 				m_freem(info.nmi_mrep);
1007 				error = 0;
1008 				tv.tv_sec = trylater_delay;
1009 				tv.tv_usec = 0;
1010 				tsleep(&tv, PSOCK, "nfsretry", tvtohz(&tv));
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 retranmit 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 = (*so->so_proto->pr_usrreq)(so, PRU_SEND,
1190 				    m, NULL, NULL, curproc);
1191 			else
1192 			    	error = (*so->so_proto->pr_usrreq)(so, PRU_SEND,
1193 				    m, nmp->nm_nam, NULL, curproc);
1194 			if (error) {
1195 				if (NFSIGNORE_SOERROR(nmp->nm_soflags, error))
1196 					so->so_error = 0;
1197 			} else {
1198 				/*
1199 				 * Iff first send, start timing
1200 				 * else turn timing off, backoff timer
1201 				 * and divide congestion window by 2.
1202 				 */
1203 				if (rep->r_flags & R_SENT) {
1204 					rep->r_flags &= ~R_TIMING;
1205 					if (++rep->r_rexmit > NFS_MAXREXMIT)
1206 						rep->r_rexmit = NFS_MAXREXMIT;
1207 					nmp->nm_cwnd >>= 1;
1208 					if (nmp->nm_cwnd < NFS_CWNDSCALE)
1209 						nmp->nm_cwnd = NFS_CWNDSCALE;
1210 					nfsstats.rpcretries++;
1211 				} else {
1212 					rep->r_flags |= R_SENT;
1213 					nmp->nm_sent += NFS_CWNDSCALE;
1214 				}
1215 				rep->r_rtt = 0;
1216 			}
1217 		}
1218 	}
1219 	NET_UNLOCK();
1220 	timeout_add(&nmp->nm_rtimeout, nfs_ticks);
1221 }
1222 
1223 /*
1224  * Test for a termination condition pending on the process.
1225  * This is used for NFSMNT_INT mounts.
1226  */
1227 int
1228 nfs_sigintr(struct nfsmount *nmp, struct nfsreq *rep, struct proc *p)
1229 {
1230 
1231 	if (rep && (rep->r_flags & R_SOFTTERM))
1232 		return (EINTR);
1233 	if (!(nmp->nm_flag & NFSMNT_INT))
1234 		return (0);
1235 	if (p && p->p_siglist &&
1236 	    (((p->p_siglist & ~p->p_sigmask) &
1237 	    ~p->p_p->ps_sigacts->ps_sigignore) & NFSINT_SIGMASK))
1238 		return (EINTR);
1239 	return (0);
1240 }
1241 
1242 /*
1243  * Lock a socket against others.
1244  * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
1245  * and also to avoid race conditions between the processes with nfs requests
1246  * in progress when a reconnect is necessary.
1247  */
1248 int
1249 nfs_sndlock(int *flagp, struct nfsreq *rep)
1250 {
1251 	struct proc *p;
1252 	int slpflag = 0, slptimeo = 0;
1253 
1254 	if (rep) {
1255 		p = rep->r_procp;
1256 		if (rep->r_nmp->nm_flag & NFSMNT_INT)
1257 			slpflag = PCATCH;
1258 	} else
1259 		p = NULL;
1260 	while (*flagp & NFSMNT_SNDLOCK) {
1261 		if (rep && nfs_sigintr(rep->r_nmp, rep, p))
1262 			return (EINTR);
1263 		*flagp |= NFSMNT_WANTSND;
1264 		(void)tsleep((caddr_t)flagp, slpflag | (PZERO - 1), "nfsndlck",
1265 		    slptimeo);
1266 		if (slpflag == PCATCH) {
1267 			slpflag = 0;
1268 			slptimeo = 2 * hz;
1269 		}
1270 	}
1271 	*flagp |= NFSMNT_SNDLOCK;
1272 	return (0);
1273 }
1274 
1275 /*
1276  * Unlock the stream socket for others.
1277  */
1278 void
1279 nfs_sndunlock(int *flagp)
1280 {
1281 
1282 	if ((*flagp & NFSMNT_SNDLOCK) == 0)
1283 		panic("nfs sndunlock");
1284 	*flagp &= ~NFSMNT_SNDLOCK;
1285 	if (*flagp & NFSMNT_WANTSND) {
1286 		*flagp &= ~NFSMNT_WANTSND;
1287 		wakeup((caddr_t)flagp);
1288 	}
1289 }
1290 
1291 int
1292 nfs_rcvlock(struct nfsreq *rep)
1293 {
1294 	int *flagp = &rep->r_nmp->nm_flag;
1295 	int slpflag, slptimeo = 0;
1296 
1297 	if (*flagp & NFSMNT_INT)
1298 		slpflag = PCATCH;
1299 	else
1300 		slpflag = 0;
1301 
1302 	while (*flagp & NFSMNT_RCVLOCK) {
1303 		if (nfs_sigintr(rep->r_nmp, rep, rep->r_procp))
1304 			return (EINTR);
1305 		*flagp |= NFSMNT_WANTRCV;
1306 		(void)tsleep((caddr_t)flagp, slpflag | (PZERO - 1), "nfsrcvlk",
1307 		    slptimeo);
1308 		if (rep->r_mrep != NULL) {
1309 			/*
1310 			 * Don't take the lock if our reply has been received
1311 			 * while we where sleeping.
1312 			 */
1313 			 return (EALREADY);
1314 		}
1315 		if (slpflag == PCATCH) {
1316 			slpflag = 0;
1317 			slptimeo = 2 * hz;
1318 		}
1319 	}
1320 	*flagp |= NFSMNT_RCVLOCK;
1321 	return (0);
1322 }
1323 
1324 /*
1325  * Unlock the stream socket for others.
1326  */
1327 void
1328 nfs_rcvunlock(int *flagp)
1329 {
1330 
1331 	if ((*flagp & NFSMNT_RCVLOCK) == 0)
1332 		panic("nfs rcvunlock");
1333 	*flagp &= ~NFSMNT_RCVLOCK;
1334 	if (*flagp & NFSMNT_WANTRCV) {
1335 		*flagp &= ~NFSMNT_WANTRCV;
1336 		wakeup(flagp);
1337 	}
1338 }
1339 
1340 /*
1341  * Auxiliary routine to align the length of mbuf copies made with m_copyback().
1342  */
1343 void
1344 nfs_realign_fixup(struct mbuf *m, struct mbuf *n, unsigned int *off)
1345 {
1346 	size_t padding;
1347 
1348 	/*
1349 	 * The maximum number of bytes that m_copyback() places in a mbuf is
1350 	 * always an aligned quantity, so realign happens at the chain's tail.
1351 	 */
1352 	while (n->m_next != NULL)
1353 		n = n->m_next;
1354 
1355 	/*
1356 	 * Pad from the next elements in the source chain. Loop until the
1357 	 * destination chain is aligned, or the end of the source is reached.
1358 	 */
1359 	do {
1360 		m = m->m_next;
1361 		if (m == NULL)
1362 			return;
1363 
1364 		padding = min(ALIGN(n->m_len) - n->m_len, m->m_len);
1365 		if (padding > M_TRAILINGSPACE(n))
1366 			panic("nfs_realign_fixup: no memory to pad to");
1367 
1368 		bcopy(mtod(m, void *), mtod(n, char *) + n->m_len, padding);
1369 
1370 		n->m_len += padding;
1371 		m_adj(m, padding);
1372 		*off += padding;
1373 
1374 	} while (!ALIGNED_POINTER(n->m_len, void *));
1375 }
1376 
1377 /*
1378  * The NFS RPC parsing code uses the data address and the length of mbuf
1379  * structures to calculate on-memory addresses. This function makes sure these
1380  * parameters are correctly aligned.
1381  */
1382 void
1383 nfs_realign(struct mbuf **pm, int hsiz)
1384 {
1385 	struct mbuf *m;
1386 	struct mbuf *n = NULL;
1387 	unsigned int off = 0;
1388 
1389 	++nfs_realign_test;
1390 	while ((m = *pm) != NULL) {
1391 		if (!ALIGNED_POINTER(m->m_data, void *) ||
1392 		    !ALIGNED_POINTER(m->m_len,  void *)) {
1393 			MGET(n, M_WAIT, MT_DATA);
1394 #define ALIGN_POINTER(n) ((u_int)(((n) + sizeof(void *)) & ~sizeof(void *)))
1395 			if (ALIGN_POINTER(m->m_len) >= MINCLSIZE) {
1396 				MCLGET(n, M_WAIT);
1397 			}
1398 			n->m_len = 0;
1399 			break;
1400 		}
1401 		pm = &m->m_next;
1402 	}
1403 	/*
1404 	 * If n is non-NULL, loop on m copying data, then replace the
1405 	 * portion of the chain that had to be realigned.
1406 	 */
1407 	if (n != NULL) {
1408 		++nfs_realign_count;
1409 		while (m) {
1410 			m_copyback(n, off, m->m_len, mtod(m, caddr_t), M_WAIT);
1411 
1412 			/*
1413 			 * If an unaligned amount of memory was copied, fix up
1414 			 * the last mbuf created by m_copyback().
1415 			 */
1416 			if (!ALIGNED_POINTER(m->m_len, void *))
1417 				nfs_realign_fixup(m, n, &off);
1418 
1419 			off += m->m_len;
1420 			m = m->m_next;
1421 		}
1422 		m_freemp(pm);
1423 		*pm = n;
1424 	}
1425 }
1426 
1427 
1428 /*
1429  * Parse an RPC request
1430  * - verify it
1431  * - fill in the cred struct.
1432  */
1433 int
1434 nfs_getreq(struct nfsrv_descript *nd, struct nfsd *nfsd, int has_header)
1435 {
1436 	int len, i;
1437 	u_int32_t *tl;
1438 	int32_t t1;
1439 	caddr_t cp2;
1440 	u_int32_t nfsvers, auth_type;
1441 	int error = 0;
1442 	struct nfsm_info info;
1443 
1444 	info.nmi_mrep = nd->nd_mrep;
1445 	info.nmi_md = nd->nd_md;
1446 	info.nmi_dpos = nd->nd_dpos;
1447 	if (has_header) {
1448 		nfsm_dissect(tl, u_int32_t *, 10 * NFSX_UNSIGNED);
1449 		nd->nd_retxid = fxdr_unsigned(u_int32_t, *tl++);
1450 		if (*tl++ != rpc_call) {
1451 			m_freem(info.nmi_mrep);
1452 			return (EBADRPC);
1453 		}
1454 	} else
1455 		nfsm_dissect(tl, u_int32_t *, 8 * NFSX_UNSIGNED);
1456 	nd->nd_repstat = 0;
1457 	nd->nd_flag = 0;
1458 	if (*tl++ != rpc_vers) {
1459 		nd->nd_repstat = ERPCMISMATCH;
1460 		nd->nd_procnum = NFSPROC_NOOP;
1461 		return (0);
1462 	}
1463 	if (*tl != nfs_prog) {
1464 		nd->nd_repstat = EPROGUNAVAIL;
1465 		nd->nd_procnum = NFSPROC_NOOP;
1466 		return (0);
1467 	}
1468 	tl++;
1469 	nfsvers = fxdr_unsigned(u_int32_t, *tl++);
1470 	if (nfsvers != NFS_VER2 && nfsvers != NFS_VER3) {
1471 		nd->nd_repstat = EPROGMISMATCH;
1472 		nd->nd_procnum = NFSPROC_NOOP;
1473 		return (0);
1474 	}
1475 	if (nfsvers == NFS_VER3)
1476 		nd->nd_flag = ND_NFSV3;
1477 	nd->nd_procnum = fxdr_unsigned(u_int32_t, *tl++);
1478 	if (nd->nd_procnum == NFSPROC_NULL)
1479 		return (0);
1480 	if (nd->nd_procnum >= NFS_NPROCS ||
1481 		(nd->nd_procnum > NFSPROC_COMMIT) ||
1482 		(!nd->nd_flag && nd->nd_procnum > NFSV2PROC_STATFS)) {
1483 		nd->nd_repstat = EPROCUNAVAIL;
1484 		nd->nd_procnum = NFSPROC_NOOP;
1485 		return (0);
1486 	}
1487 	if ((nd->nd_flag & ND_NFSV3) == 0)
1488 		nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
1489 	auth_type = *tl++;
1490 	len = fxdr_unsigned(int, *tl++);
1491 	if (len < 0 || len > RPCAUTH_MAXSIZ) {
1492 		m_freem(info.nmi_mrep);
1493 		return (EBADRPC);
1494 	}
1495 
1496 	/* Handle auth_unix */
1497 	if (auth_type == rpc_auth_unix) {
1498 		len = fxdr_unsigned(int, *++tl);
1499 		if (len < 0 || len > NFS_MAXNAMLEN) {
1500 			m_freem(info.nmi_mrep);
1501 			return (EBADRPC);
1502 		}
1503 		nfsm_adv(nfsm_rndup(len));
1504 		nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
1505 		memset(&nd->nd_cr, 0, sizeof (struct ucred));
1506 		nd->nd_cr.cr_ref = 1;
1507 		nd->nd_cr.cr_uid = fxdr_unsigned(uid_t, *tl++);
1508 		nd->nd_cr.cr_gid = fxdr_unsigned(gid_t, *tl++);
1509 		len = fxdr_unsigned(int, *tl);
1510 		if (len < 0 || len > RPCAUTH_UNIXGIDS) {
1511 			m_freem(info.nmi_mrep);
1512 			return (EBADRPC);
1513 		}
1514 		nfsm_dissect(tl, u_int32_t *, (len + 2) * NFSX_UNSIGNED);
1515 		for (i = 0; i < len; i++) {
1516 			if (i < NGROUPS_MAX)
1517 				nd->nd_cr.cr_groups[i] =
1518 				    fxdr_unsigned(gid_t, *tl++);
1519 			else
1520 				tl++;
1521 		}
1522 		nd->nd_cr.cr_ngroups = (len > NGROUPS_MAX) ? NGROUPS_MAX : len;
1523 		len = fxdr_unsigned(int, *++tl);
1524 		if (len < 0 || len > RPCAUTH_MAXSIZ) {
1525 			m_freem(info.nmi_mrep);
1526 			return (EBADRPC);
1527 		}
1528 		if (len > 0)
1529 			nfsm_adv(nfsm_rndup(len));
1530 	} else {
1531 		nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
1532 		nd->nd_procnum = NFSPROC_NOOP;
1533 		return (0);
1534 	}
1535 
1536 	nd->nd_md = info.nmi_md;
1537 	nd->nd_dpos = info.nmi_dpos;
1538 	return (0);
1539 nfsmout:
1540 	return (error);
1541 }
1542 
1543 void
1544 nfs_msg(struct nfsreq *rep, char *msg)
1545 {
1546 	tpr_t tpr;
1547 
1548 	if (rep->r_procp)
1549 		tpr = tprintf_open(rep->r_procp);
1550 	else
1551 		tpr = NULL;
1552 
1553 	tprintf(tpr, "nfs server %s: %s\n",
1554 	    rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname, msg);
1555 	tprintf_close(tpr);
1556 }
1557 
1558 #ifdef NFSSERVER
1559 /*
1560  * Socket upcall routine for the nfsd sockets.
1561  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
1562  * Essentially do as much as possible non-blocking, else punt and it will
1563  * be called with M_WAIT from an nfsd.
1564  */
1565 void
1566 nfsrv_rcv(struct socket *so, caddr_t arg, int waitflag)
1567 {
1568 	struct nfssvc_sock *slp = (struct nfssvc_sock *)arg;
1569 	struct mbuf *m;
1570 	struct mbuf *mp, *nam;
1571 	struct uio auio;
1572 	int flags, error;
1573 
1574 	if ((slp->ns_flag & SLP_VALID) == 0)
1575 		return;
1576 
1577 	/* Defer soreceive() to an nfsd. */
1578 	if (waitflag == M_DONTWAIT) {
1579 		slp->ns_flag |= SLP_NEEDQ;
1580 		goto dorecs;
1581 	}
1582 
1583 	auio.uio_procp = NULL;
1584 	if (so->so_type == SOCK_STREAM) {
1585 		/*
1586 		 * Do soreceive().
1587 		 */
1588 		auio.uio_resid = 1000000000;
1589 		flags = MSG_DONTWAIT;
1590 		error = soreceive(so, &nam, &auio, &mp, NULL,
1591 		    &flags, 0);
1592 		if (error || mp == NULL) {
1593 			if (error == EWOULDBLOCK)
1594 				slp->ns_flag |= SLP_NEEDQ;
1595 			else
1596 				slp->ns_flag |= SLP_DISCONN;
1597 			goto dorecs;
1598 		}
1599 		m = mp;
1600 		if (slp->ns_rawend) {
1601 			slp->ns_rawend->m_next = m;
1602 			slp->ns_cc += 1000000000 - auio.uio_resid;
1603 		} else {
1604 			slp->ns_raw = m;
1605 			slp->ns_cc = 1000000000 - auio.uio_resid;
1606 		}
1607 		while (m->m_next)
1608 			m = m->m_next;
1609 		slp->ns_rawend = m;
1610 
1611 		/*
1612 		 * Now try and parse record(s) out of the raw stream data.
1613 		 */
1614 		error = nfsrv_getstream(slp, waitflag);
1615 		if (error) {
1616 			if (error == EPERM)
1617 				slp->ns_flag |= SLP_DISCONN;
1618 			else
1619 				slp->ns_flag |= SLP_NEEDQ;
1620 		}
1621 	} else {
1622 		do {
1623 			auio.uio_resid = 1000000000;
1624 			flags = MSG_DONTWAIT;
1625 			error = soreceive(so, &nam, &auio, &mp,
1626 			    NULL, &flags, 0);
1627 			if (mp) {
1628 				if (nam) {
1629 					m = nam;
1630 					m->m_next = mp;
1631 				} else
1632 					m = mp;
1633 				if (slp->ns_recend)
1634 					slp->ns_recend->m_nextpkt = m;
1635 				else
1636 					slp->ns_rec = m;
1637 				slp->ns_recend = m;
1638 				m->m_nextpkt = NULL;
1639 			}
1640 			if (error) {
1641 				if ((so->so_proto->pr_flags & PR_CONNREQUIRED)
1642 					&& error != EWOULDBLOCK) {
1643 					slp->ns_flag |= SLP_DISCONN;
1644 					goto dorecs;
1645 				}
1646 			}
1647 		} while (mp);
1648 	}
1649 
1650 	/*
1651 	 * Now try and process the request records, non-blocking.
1652 	 */
1653 dorecs:
1654 	if (waitflag == M_DONTWAIT &&
1655 		(slp->ns_rec || (slp->ns_flag & (SLP_NEEDQ | SLP_DISCONN))))
1656 		nfsrv_wakenfsd(slp);
1657 }
1658 
1659 /*
1660  * Try and extract an RPC request from the mbuf data list received on a
1661  * stream socket. The "waitflag" argument indicates whether or not it
1662  * can sleep.
1663  */
1664 int
1665 nfsrv_getstream(struct nfssvc_sock *slp, int waitflag)
1666 {
1667 	struct mbuf *m, **mpp;
1668 	char *cp1, *cp2;
1669 	int len;
1670 	struct mbuf *om, *m2, *recm;
1671 	u_int32_t recmark;
1672 
1673 	if (slp->ns_flag & SLP_GETSTREAM)
1674 		return (0);
1675 	slp->ns_flag |= SLP_GETSTREAM;
1676 	for (;;) {
1677 		if (slp->ns_reclen == 0) {
1678 			if (slp->ns_cc < NFSX_UNSIGNED) {
1679 				slp->ns_flag &= ~SLP_GETSTREAM;
1680 				return (0);
1681 			}
1682 			m = slp->ns_raw;
1683 			if (m->m_len >= NFSX_UNSIGNED) {
1684 				bcopy(mtod(m, caddr_t), &recmark,
1685 				    NFSX_UNSIGNED);
1686 				m->m_data += NFSX_UNSIGNED;
1687 				m->m_len -= NFSX_UNSIGNED;
1688 			} else {
1689 				cp1 = (caddr_t)&recmark;
1690 				cp2 = mtod(m, caddr_t);
1691 				while (cp1 < ((caddr_t)&recmark) + NFSX_UNSIGNED) {
1692 					while (m->m_len == 0) {
1693 						m = m->m_next;
1694 						cp2 = mtod(m, caddr_t);
1695 					}
1696 					*cp1++ = *cp2++;
1697 					m->m_data++;
1698 					m->m_len--;
1699 				}
1700 			}
1701 			slp->ns_cc -= NFSX_UNSIGNED;
1702 			recmark = ntohl(recmark);
1703 			slp->ns_reclen = recmark & ~0x80000000;
1704 			if (recmark & 0x80000000)
1705 				slp->ns_flag |= SLP_LASTFRAG;
1706 			else
1707 				slp->ns_flag &= ~SLP_LASTFRAG;
1708 			if (slp->ns_reclen > NFS_MAXPACKET) {
1709 				slp->ns_flag &= ~SLP_GETSTREAM;
1710 				return (EPERM);
1711 			}
1712 		}
1713 
1714 		/*
1715 		 * Now get the record part.
1716 		 */
1717 		recm = NULL;
1718 		if (slp->ns_cc == slp->ns_reclen) {
1719 			recm = slp->ns_raw;
1720 			slp->ns_raw = slp->ns_rawend = NULL;
1721 			slp->ns_cc = slp->ns_reclen = 0;
1722 		} else if (slp->ns_cc > slp->ns_reclen) {
1723 			len = 0;
1724 			m = slp->ns_raw;
1725 			om = NULL;
1726 			while (len < slp->ns_reclen) {
1727 				if ((len + m->m_len) > slp->ns_reclen) {
1728 					m2 = m_copym(m, 0, slp->ns_reclen - len,
1729 					    waitflag);
1730 					if (m2) {
1731 						if (om) {
1732 							om->m_next = m2;
1733 							recm = slp->ns_raw;
1734 						} else
1735 							recm = m2;
1736 						m->m_data += slp->ns_reclen-len;
1737 						m->m_len -= slp->ns_reclen-len;
1738 						len = slp->ns_reclen;
1739 					} else {
1740 						slp->ns_flag &= ~SLP_GETSTREAM;
1741 						return (EWOULDBLOCK);
1742 					}
1743 				} else if ((len + m->m_len) == slp->ns_reclen) {
1744 					om = m;
1745 					len += m->m_len;
1746 					m = m->m_next;
1747 					recm = slp->ns_raw;
1748 					om->m_next = NULL;
1749 				} else {
1750 					om = m;
1751 					len += m->m_len;
1752 					m = m->m_next;
1753 				}
1754 			}
1755 			slp->ns_raw = m;
1756 			slp->ns_cc -= len;
1757 			slp->ns_reclen = 0;
1758 		} else {
1759 			slp->ns_flag &= ~SLP_GETSTREAM;
1760 			return (0);
1761 		}
1762 
1763 		/*
1764 		 * Accumulate the fragments into a record.
1765 		 */
1766 		mpp = &slp->ns_frag;
1767 		while (*mpp)
1768 			mpp = &((*mpp)->m_next);
1769 		*mpp = recm;
1770 		if (slp->ns_flag & SLP_LASTFRAG) {
1771 			if (slp->ns_recend)
1772 			    slp->ns_recend->m_nextpkt = slp->ns_frag;
1773 			else
1774 			    slp->ns_rec = slp->ns_frag;
1775 			slp->ns_recend = slp->ns_frag;
1776 			slp->ns_frag = NULL;
1777 		}
1778 	}
1779 }
1780 
1781 /*
1782  * Parse an RPC header.
1783  */
1784 int
1785 nfsrv_dorec(struct nfssvc_sock *slp, struct nfsd *nfsd,
1786     struct nfsrv_descript **ndp)
1787 {
1788 	struct mbuf *m, *nam;
1789 	struct nfsrv_descript *nd;
1790 	int error;
1791 
1792 	*ndp = NULL;
1793 	if ((slp->ns_flag & SLP_VALID) == 0 ||
1794 	    (m = slp->ns_rec) == NULL)
1795 		return (ENOBUFS);
1796 	slp->ns_rec = m->m_nextpkt;
1797 	if (slp->ns_rec)
1798 		m->m_nextpkt = NULL;
1799 	else
1800 		slp->ns_recend = NULL;
1801 	if (m->m_type == MT_SONAME) {
1802 		nam = m;
1803 		m = m->m_next;
1804 		nam->m_next = NULL;
1805 	} else
1806 		nam = NULL;
1807 	nd = pool_get(&nfsrv_descript_pl, PR_WAITOK);
1808 	nfs_realign(&m, 10 * NFSX_UNSIGNED);
1809 	nd->nd_md = nd->nd_mrep = m;
1810 	nd->nd_nam2 = nam;
1811 	nd->nd_dpos = mtod(m, caddr_t);
1812 	error = nfs_getreq(nd, nfsd, 1);
1813 	if (error) {
1814 		m_freem(nam);
1815 		pool_put(&nfsrv_descript_pl, nd);
1816 		return (error);
1817 	}
1818 	*ndp = nd;
1819 	nfsd->nfsd_nd = nd;
1820 	return (0);
1821 }
1822 
1823 
1824 /*
1825  * Search for a sleeping nfsd and wake it up.
1826  * SIDE EFFECT: If none found, set NFSD_CHECKSLP flag, so that one of the
1827  * running nfsds will go look for the work in the nfssvc_sock list.
1828  */
1829 void
1830 nfsrv_wakenfsd(struct nfssvc_sock *slp)
1831 {
1832 	struct nfsd	*nfsd;
1833 
1834 	if ((slp->ns_flag & SLP_VALID) == 0)
1835 		return;
1836 
1837 	TAILQ_FOREACH(nfsd, &nfsd_head, nfsd_chain) {
1838 		if (nfsd->nfsd_flag & NFSD_WAITING) {
1839 			nfsd->nfsd_flag &= ~NFSD_WAITING;
1840 			if (nfsd->nfsd_slp)
1841 				panic("nfsd wakeup");
1842 			slp->ns_sref++;
1843 			nfsd->nfsd_slp = slp;
1844 			wakeup_one(nfsd);
1845 			return;
1846 		}
1847 	}
1848 
1849 	slp->ns_flag |= SLP_DOREC;
1850 	nfsd_head_flag |= NFSD_CHECKSLP;
1851 }
1852 #endif /* NFSSERVER */
1853