xref: /openbsd-src/sys/nfs/nfs_socket.c (revision e5157e49389faebcb42b7237d55fbf096d9c2523)
1 /*	$OpenBSD: nfs_socket.c,v 1.106 2014/11/14 23:01:44 tedu 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/nfsnode.h>
70 #include <nfs/nfs_var.h>
71 
72 /* External data, mostly RPC constants in XDR form. */
73 extern u_int32_t rpc_reply, rpc_msgdenied, rpc_mismatch, rpc_vers,
74 	rpc_auth_unix, rpc_msgaccepted, rpc_call, rpc_autherr;
75 extern u_int32_t nfs_prog;
76 extern struct nfsstats nfsstats;
77 extern int nfsv3_procid[NFS_NPROCS];
78 extern int nfs_ticks;
79 
80 extern struct pool nfsrv_descript_pl;
81 
82 /*
83  * There is a congestion window for outstanding rpcs maintained per mount
84  * point. The cwnd size is adjusted in roughly the way that:
85  * Van Jacobson, Congestion avoidance and Control, In "Proceedings of
86  * SIGCOMM '88". ACM, August 1988.
87  * describes for TCP. The cwnd size is chopped in half on a retransmit timeout
88  * and incremented by 1/cwnd when each rpc reply is received and a full cwnd
89  * of rpcs is in progress.
90  * (The sent count and cwnd are scaled for integer arith.)
91  * Variants of "slow start" were tried and were found to be too much of a
92  * performance hit (ave. rtt 3 times larger),
93  * I suspect due to the large rtt that nfs rpcs have.
94  */
95 #define	NFS_CWNDSCALE	256
96 #define	NFS_MAXCWND	(NFS_CWNDSCALE * 32)
97 int nfs_backoff[8] = { 2, 4, 8, 16, 32, 64, 128, 256 };
98 
99 /* RTT estimator */
100 enum nfs_rto_timers nfs_ptimers[NFS_NPROCS] = {
101 	NFS_DEFAULT_TIMER,	/* NULL */
102 	NFS_GETATTR_TIMER,	/* GETATTR */
103 	NFS_DEFAULT_TIMER,	/* SETATTR */
104 	NFS_LOOKUP_TIMER,	/* LOOKUP */
105 	NFS_GETATTR_TIMER,	/* ACCESS */
106 	NFS_READ_TIMER,		/* READLINK */
107 	NFS_READ_TIMER,		/* READ */
108 	NFS_WRITE_TIMER,	/* WRITE */
109 	NFS_DEFAULT_TIMER,	/* CREATE */
110 	NFS_DEFAULT_TIMER,	/* MKDIR */
111 	NFS_DEFAULT_TIMER,	/* SYMLINK */
112 	NFS_DEFAULT_TIMER,	/* MKNOD */
113 	NFS_DEFAULT_TIMER,	/* REMOVE */
114 	NFS_DEFAULT_TIMER,	/* RMDIR */
115 	NFS_DEFAULT_TIMER,	/* RENAME */
116 	NFS_DEFAULT_TIMER,	/* LINK */
117 	NFS_READ_TIMER,		/* READDIR */
118 	NFS_READ_TIMER,		/* READDIRPLUS */
119 	NFS_DEFAULT_TIMER,	/* FSSTAT */
120 	NFS_DEFAULT_TIMER,	/* FSINFO */
121 	NFS_DEFAULT_TIMER,	/* PATHCONF */
122 	NFS_DEFAULT_TIMER,	/* COMMIT */
123 	NFS_DEFAULT_TIMER,	/* NOOP */
124 };
125 
126 void nfs_init_rtt(struct nfsmount *);
127 void nfs_update_rtt(struct nfsreq *);
128 int  nfs_estimate_rto(struct nfsmount *, u_int32_t procnum);
129 
130 void nfs_realign(struct mbuf **, int);
131 void nfs_realign_fixup(struct mbuf *, struct mbuf *, unsigned int *);
132 unsigned int nfs_realign_test = 0;
133 unsigned int nfs_realign_count = 0;
134 
135 /* Initialize the RTT estimator state for a new mount point. */
136 void
137 nfs_init_rtt(struct nfsmount *nmp)
138 {
139 	int i;
140 
141 	for (i = 0; i < NFS_MAX_TIMER; i++)
142 		nmp->nm_srtt[i] = NFS_INITRTT;
143 	for (i = 0; i < NFS_MAX_TIMER; i++)
144 		nmp->nm_sdrtt[i] = 0;
145 }
146 
147 /*
148  * Update a mount point's RTT estimator state using data from the
149  * passed-in request.
150  *
151  * Use a gain of 0.125 on the mean and a gain of 0.25 on the deviation.
152  *
153  * NB: Since the timer resolution of NFS_HZ is so course, it can often
154  * result in r_rtt == 0. Since r_rtt == N means that the actual RTT is
155  * between N + dt and N + 2 - dt ticks, add 1 before calculating the
156  * update values.
157  */
158 void
159 nfs_update_rtt(struct nfsreq *rep)
160 {
161 	int t1 = rep->r_rtt + 1;
162 	int index = nfs_ptimers[rep->r_procnum] - 1;
163 	int *srtt = &rep->r_nmp->nm_srtt[index];
164 	int *sdrtt = &rep->r_nmp->nm_sdrtt[index];
165 
166 	t1 -= *srtt >> 3;
167 	*srtt += t1;
168 	if (t1 < 0)
169 		t1 = -t1;
170 	t1 -= *sdrtt >> 2;
171 	*sdrtt += t1;
172 }
173 
174 /*
175  * Estimate RTO for an NFS RPC sent via an unreliable datagram.
176  *
177  * Use the mean and mean deviation of RTT for the appropriate type
178  * of RPC for the frequent RPCs and a default for the others.
179  * The justification for doing "other" this way is that these RPCs
180  * happen so infrequently that timer est. would probably be stale.
181  * Also, since many of these RPCs are non-idempotent, a conservative
182  * timeout is desired.
183  *
184  * getattr, lookup - A+2D
185  * read, write     - A+4D
186  * other           - nm_timeo
187  */
188 int
189 nfs_estimate_rto(struct nfsmount *nmp, u_int32_t procnum)
190 {
191 	enum nfs_rto_timers timer = nfs_ptimers[procnum];
192 	int index = timer - 1;
193 	int rto;
194 
195 	switch (timer) {
196 	case NFS_GETATTR_TIMER:
197 	case NFS_LOOKUP_TIMER:
198 		rto = ((nmp->nm_srtt[index] + 3) >> 2) +
199 				((nmp->nm_sdrtt[index] + 1) >> 1);
200 		break;
201 	case NFS_READ_TIMER:
202 	case NFS_WRITE_TIMER:
203 		rto = ((nmp->nm_srtt[index] + 7) >> 3) +
204 				(nmp->nm_sdrtt[index] + 1);
205 		break;
206 	default:
207 		rto = nmp->nm_timeo;
208 		return (rto);
209 	}
210 
211 	if (rto < NFS_MINRTO)
212 		rto = NFS_MINRTO;
213 	else if (rto > NFS_MAXRTO)
214 		rto = NFS_MAXRTO;
215 
216 	return (rto);
217 }
218 
219 
220 
221 /*
222  * Initialize sockets and congestion for a new NFS connection.
223  * We do not free the sockaddr if error.
224  */
225 int
226 nfs_connect(struct nfsmount *nmp, struct nfsreq *rep)
227 {
228 	struct socket *so;
229 	int s, error, rcvreserve, sndreserve;
230 	struct sockaddr *saddr;
231 	struct sockaddr_in *sin;
232 	struct mbuf *m;
233 
234 	nmp->nm_so = NULL;
235 	saddr = mtod(nmp->nm_nam, struct sockaddr *);
236 	error = socreate(saddr->sa_family, &nmp->nm_so, nmp->nm_sotype,
237 		nmp->nm_soproto);
238 	if (error)
239 		goto bad;
240 	so = nmp->nm_so;
241 	nmp->nm_soflags = so->so_proto->pr_flags;
242 
243 	/*
244 	 * Some servers require that the client port be a reserved port number.
245 	 * We always allocate a reserved port, as this prevents filehandle
246 	 * disclosure through UDP port capture.
247 	 */
248 	if (saddr->sa_family == AF_INET) {
249 		struct mbuf *mopt;
250 		int *ip;
251 
252 		MGET(mopt, M_WAIT, MT_SOOPTS);
253 		mopt->m_len = sizeof(int);
254 		ip = mtod(mopt, int *);
255 		*ip = IP_PORTRANGE_LOW;
256 		error = sosetopt(so, IPPROTO_IP, IP_PORTRANGE, mopt);
257 		if (error)
258 			goto bad;
259 
260 		MGET(m, M_WAIT, MT_SONAME);
261 		sin = mtod(m, struct sockaddr_in *);
262 		sin->sin_len = m->m_len = sizeof (struct sockaddr_in);
263 		sin->sin_family = AF_INET;
264 		sin->sin_addr.s_addr = INADDR_ANY;
265 		sin->sin_port = htons(0);
266 		error = sobind(so, m, &proc0);
267 		m_freem(m);
268 		if (error)
269 			goto bad;
270 
271 		MGET(mopt, M_WAIT, MT_SOOPTS);
272 		mopt->m_len = sizeof(int);
273 		ip = mtod(mopt, int *);
274 		*ip = IP_PORTRANGE_DEFAULT;
275 		error = sosetopt(so, IPPROTO_IP, IP_PORTRANGE, mopt);
276 		if (error)
277 			goto bad;
278 	}
279 
280 	/*
281 	 * Protocols that do not require connections may be optionally left
282 	 * unconnected for servers that reply from a port other than NFS_PORT.
283 	 */
284 	if (nmp->nm_flag & NFSMNT_NOCONN) {
285 		if (nmp->nm_soflags & PR_CONNREQUIRED) {
286 			error = ENOTCONN;
287 			goto bad;
288 		}
289 	} else {
290 		error = soconnect(so, nmp->nm_nam);
291 		if (error)
292 			goto bad;
293 
294 		/*
295 		 * Wait for the connection to complete. Cribbed from the
296 		 * connect system call but with the wait timing out so
297 		 * that interruptible mounts don't hang here for a long time.
298 		 */
299 		s = splsoftnet();
300 		while ((so->so_state & SS_ISCONNECTING) && so->so_error == 0) {
301 			(void) tsleep((caddr_t)&so->so_timeo, PSOCK,
302 				"nfscon", 2 * hz);
303 			if ((so->so_state & SS_ISCONNECTING) &&
304 			    so->so_error == 0 && rep &&
305 			    (error = nfs_sigintr(nmp, rep, rep->r_procp)) != 0){
306 				so->so_state &= ~SS_ISCONNECTING;
307 				splx(s);
308 				goto bad;
309 			}
310 		}
311 		if (so->so_error) {
312 			error = so->so_error;
313 			so->so_error = 0;
314 			splx(s);
315 			goto bad;
316 		}
317 		splx(s);
318 	}
319 	/*
320 	 * Always set receive timeout to detect server crash and reconnect.
321 	 * Otherwise, we can get stuck in soreceive forever.
322 	 */
323 	so->so_rcv.sb_timeo = (5 * hz);
324 	if (nmp->nm_flag & (NFSMNT_SOFT | NFSMNT_INT))
325 		so->so_snd.sb_timeo = (5 * hz);
326 	else
327 		so->so_snd.sb_timeo = 0;
328 	if (nmp->nm_sotype == SOCK_DGRAM) {
329 		sndreserve = nmp->nm_wsize + NFS_MAXPKTHDR;
330 		rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
331 		    NFS_MAXPKTHDR) * 2;
332 	} else if (nmp->nm_sotype == SOCK_SEQPACKET) {
333 		sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR) * 2;
334 		rcvreserve = (max(nmp->nm_rsize, nmp->nm_readdirsize) +
335 		    NFS_MAXPKTHDR) * 2;
336 	} else {
337 		if (nmp->nm_sotype != SOCK_STREAM)
338 			panic("nfscon sotype");
339 		if (so->so_proto->pr_flags & PR_CONNREQUIRED) {
340 			MGET(m, M_WAIT, MT_SOOPTS);
341 			*mtod(m, int32_t *) = 1;
342 			m->m_len = sizeof(int32_t);
343 			sosetopt(so, SOL_SOCKET, SO_KEEPALIVE, m);
344 		}
345 		if (so->so_proto->pr_protocol == IPPROTO_TCP) {
346 			MGET(m, M_WAIT, MT_SOOPTS);
347 			*mtod(m, int32_t *) = 1;
348 			m->m_len = sizeof(int32_t);
349 			sosetopt(so, IPPROTO_TCP, TCP_NODELAY, m);
350 		}
351 		sndreserve = (nmp->nm_wsize + NFS_MAXPKTHDR +
352 		    sizeof (u_int32_t)) * 2;
353 		rcvreserve = (nmp->nm_rsize + NFS_MAXPKTHDR +
354 		    sizeof (u_int32_t)) * 2;
355 	}
356 	error = soreserve(so, sndreserve, rcvreserve);
357 	if (error)
358 		goto bad;
359 	so->so_rcv.sb_flags |= SB_NOINTR;
360 	so->so_snd.sb_flags |= SB_NOINTR;
361 
362 	/* Initialize other non-zero congestion variables */
363 	nfs_init_rtt(nmp);
364 	nmp->nm_cwnd = NFS_MAXCWND / 2;	    /* Initial send window */
365 	nmp->nm_sent = 0;
366 	nmp->nm_timeouts = 0;
367 	return (0);
368 
369 bad:
370 	nfs_disconnect(nmp);
371 	return (error);
372 }
373 
374 /*
375  * Reconnect routine:
376  * Called when a connection is broken on a reliable protocol.
377  * - clean up the old socket
378  * - nfs_connect() again
379  * - set R_MUSTRESEND for all outstanding requests on mount point
380  * If this fails the mount point is DEAD!
381  * nb: Must be called with the nfs_sndlock() set on the mount point.
382  */
383 int
384 nfs_reconnect(struct nfsreq *rep)
385 {
386 	struct nfsreq *rp;
387 	struct nfsmount *nmp = rep->r_nmp;
388 	int s, error;
389 
390 	nfs_disconnect(nmp);
391 	while ((error = nfs_connect(nmp, rep)) != 0) {
392 		if (error == EINTR || error == ERESTART)
393 			return (EINTR);
394 		(void) tsleep((caddr_t)&lbolt, PSOCK, "nfsrecon", 0);
395 	}
396 
397 	/*
398 	 * Loop through outstanding request list and fix up all requests
399 	 * on old socket.
400 	 */
401 	s = splsoftnet();
402 	TAILQ_FOREACH(rp, &nmp->nm_reqsq, r_chain) {
403 		rp->r_flags |= R_MUSTRESEND;
404 		rp->r_rexmit = 0;
405 	}
406 	splx(s);
407 	return (0);
408 }
409 
410 /*
411  * NFS disconnect. Clean up and unlink.
412  */
413 void
414 nfs_disconnect(struct nfsmount *nmp)
415 {
416 	struct socket *so;
417 
418 	if (nmp->nm_so) {
419 		so = nmp->nm_so;
420 		nmp->nm_so = NULL;
421 		soshutdown(so, SHUT_RDWR);
422 		soclose(so);
423 	}
424 }
425 
426 /*
427  * This is the nfs send routine. For connection based socket types, it
428  * must be called with an nfs_sndlock() on the socket.
429  * "rep == NULL" indicates that it has been called from a server.
430  * For the client side:
431  * - return EINTR if the RPC is terminated, 0 otherwise
432  * - set R_MUSTRESEND if the send fails for any reason
433  * - do any cleanup required by recoverable socket errors (???)
434  * For the server side:
435  * - return EINTR or ERESTART if interrupted by a signal
436  * - return EPIPE if a connection is lost for connection based sockets (TCP...)
437  * - do any cleanup required by recoverable socket errors (???)
438  */
439 int
440 nfs_send(struct socket *so, struct mbuf *nam, struct mbuf *top,
441     struct nfsreq *rep)
442 {
443 	struct mbuf *sendnam;
444 	int error, soflags, flags;
445 
446 	if (rep) {
447 		if (rep->r_flags & R_SOFTTERM) {
448 			m_freem(top);
449 			return (EINTR);
450 		}
451 		if ((so = rep->r_nmp->nm_so) == NULL) {
452 			rep->r_flags |= R_MUSTRESEND;
453 			m_freem(top);
454 			return (0);
455 		}
456 		rep->r_flags &= ~R_MUSTRESEND;
457 		soflags = rep->r_nmp->nm_soflags;
458 	} else
459 		soflags = so->so_proto->pr_flags;
460 	if ((soflags & PR_CONNREQUIRED) || (so->so_state & SS_ISCONNECTED))
461 		sendnam = NULL;
462 	else
463 		sendnam = nam;
464 	if (so->so_type == SOCK_SEQPACKET)
465 		flags = MSG_EOR;
466 	else
467 		flags = 0;
468 
469 	error = sosend(so, sendnam, NULL, top, NULL, flags);
470 	if (error) {
471 		if (rep) {
472 			/*
473 			 * Deal with errors for the client side.
474 			 */
475 			if (rep->r_flags & R_SOFTTERM)
476 				error = EINTR;
477 			else
478 				rep->r_flags |= R_MUSTRESEND;
479 		}
480 
481 		/*
482 		 * Handle any recoverable (soft) socket errors here. (???)
483 		 */
484 		if (error != EINTR && error != ERESTART &&
485 			error != EWOULDBLOCK && error != EPIPE)
486 			error = 0;
487 	}
488 	return (error);
489 }
490 
491 #ifdef NFSCLIENT
492 /*
493  * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
494  * done by soreceive(), but for SOCK_STREAM we must deal with the Record
495  * Mark and consolidate the data into a new mbuf list.
496  * nb: Sometimes TCP passes the data up to soreceive() in long lists of
497  *     small mbufs.
498  * For SOCK_STREAM we must be very careful to read an entire record once
499  * we have read any of it, even if the system call has been interrupted.
500  */
501 int
502 nfs_receive(struct nfsreq *rep, struct mbuf **aname, struct mbuf **mp)
503 {
504 	struct socket *so;
505 	struct uio auio;
506 	struct iovec aio;
507 	struct mbuf *m;
508 	struct mbuf *control;
509 	u_int32_t len;
510 	struct mbuf **getnam;
511 	int error, sotype, rcvflg;
512 	struct proc *p = curproc;	/* XXX */
513 
514 	/*
515 	 * Set up arguments for soreceive()
516 	 */
517 	*mp = NULL;
518 	*aname = NULL;
519 	sotype = rep->r_nmp->nm_sotype;
520 
521 	/*
522 	 * For reliable protocols, lock against other senders/receivers
523 	 * in case a reconnect is necessary.
524 	 * For SOCK_STREAM, first get the Record Mark to find out how much
525 	 * more there is to get.
526 	 * We must lock the socket against other receivers
527 	 * until we have an entire rpc request/reply.
528 	 */
529 	if (sotype != SOCK_DGRAM) {
530 		error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
531 		if (error)
532 			return (error);
533 tryagain:
534 		/*
535 		 * Check for fatal errors and resending request.
536 		 */
537 		/*
538 		 * Ugh: If a reconnect attempt just happened, nm_so
539 		 * would have changed. NULL indicates a failed
540 		 * attempt that has essentially shut down this
541 		 * mount point.
542 		 */
543 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
544 			nfs_sndunlock(&rep->r_nmp->nm_flag);
545 			return (EINTR);
546 		}
547 		so = rep->r_nmp->nm_so;
548 		if (!so) {
549 			error = nfs_reconnect(rep);
550 			if (error) {
551 				nfs_sndunlock(&rep->r_nmp->nm_flag);
552 				return (error);
553 			}
554 			goto tryagain;
555 		}
556 		while (rep->r_flags & R_MUSTRESEND) {
557 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
558 			nfsstats.rpcretries++;
559 			rep->r_rtt = 0;
560 			rep->r_flags &= ~R_TIMING;
561 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep);
562 			if (error) {
563 				if (error == EINTR || error == ERESTART ||
564 				    (error = nfs_reconnect(rep)) != 0) {
565 					nfs_sndunlock(&rep->r_nmp->nm_flag);
566 					return (error);
567 				}
568 				goto tryagain;
569 			}
570 		}
571 		nfs_sndunlock(&rep->r_nmp->nm_flag);
572 		if (sotype == SOCK_STREAM) {
573 			aio.iov_base = (caddr_t) &len;
574 			aio.iov_len = sizeof(u_int32_t);
575 			auio.uio_iov = &aio;
576 			auio.uio_iovcnt = 1;
577 			auio.uio_segflg = UIO_SYSSPACE;
578 			auio.uio_rw = UIO_READ;
579 			auio.uio_offset = 0;
580 			auio.uio_resid = sizeof(u_int32_t);
581 			auio.uio_procp = p;
582 			do {
583 			   rcvflg = MSG_WAITALL;
584 			   error = soreceive(so, NULL, &auio, NULL, NULL,
585 			       &rcvflg, 0);
586 			   if (error == EWOULDBLOCK && rep) {
587 				if (rep->r_flags & R_SOFTTERM)
588 					return (EINTR);
589 				/*
590 				 * looks like the server died after it
591 				 * received the request, make sure
592 				 * that we will retransmit and we
593 				 * don't get stuck here forever.
594 				 */
595 				if (rep->r_rexmit >= rep->r_nmp->nm_retry) {
596 					nfsstats.rpctimeouts++;
597 					error = EPIPE;
598 				}
599 			   }
600 			} while (error == EWOULDBLOCK);
601 			if (!error && auio.uio_resid > 0) {
602 			    log(LOG_INFO,
603 				 "short receive (%zu/%zu) from nfs server %s\n",
604 				 sizeof(u_int32_t) - auio.uio_resid,
605 				 sizeof(u_int32_t),
606 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
607 			    error = EPIPE;
608 			}
609 			if (error)
610 				goto errout;
611 
612 			len = ntohl(len) & ~0x80000000;
613 			/*
614 			 * This is SERIOUS! We are out of sync with the sender
615 			 * and forcing a disconnect/reconnect is all I can do.
616 			 */
617 			if (len > NFS_MAXPACKET) {
618 			    log(LOG_ERR, "%s (%u) from nfs server %s\n",
619 				"impossible packet length",
620 				len,
621 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
622 			    error = EFBIG;
623 			    goto errout;
624 			}
625 			auio.uio_resid = len;
626 			do {
627 			    rcvflg = MSG_WAITALL;
628 			    error =  soreceive(so, NULL, &auio, mp, NULL,
629 			        &rcvflg, 0);
630 			} while (error == EWOULDBLOCK || error == EINTR ||
631 				 error == ERESTART);
632 			if (!error && auio.uio_resid > 0) {
633 			    log(LOG_INFO,
634 				"short receive (%zu/%u) from nfs server %s\n",
635 				len - auio.uio_resid, len,
636 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
637 			    error = EPIPE;
638 			}
639 		} else {
640 			/*
641 			 * NB: Since uio_resid is big, MSG_WAITALL is ignored
642 			 * and soreceive() will return when it has either a
643 			 * control msg or a data msg.
644 			 * We have no use for control msg., but must grab them
645 			 * and then throw them away so we know what is going
646 			 * on.
647 			 */
648 			auio.uio_resid = len = 100000000; /* Anything Big */
649 			auio.uio_procp = p;
650 			do {
651 			    rcvflg = 0;
652 			    error =  soreceive(so, NULL, &auio, mp, &control,
653 			        &rcvflg, 0);
654 			    if (control)
655 				m_freem(control);
656 			    if (error == EWOULDBLOCK && rep) {
657 				if (rep->r_flags & R_SOFTTERM)
658 					return (EINTR);
659 			    }
660 			} while (error == EWOULDBLOCK ||
661 				 (!error && *mp == NULL && control));
662 			if ((rcvflg & MSG_EOR) == 0)
663 				printf("Egad!!\n");
664 			if (!error && *mp == NULL)
665 				error = EPIPE;
666 			len -= auio.uio_resid;
667 		}
668 errout:
669 		if (error && error != EINTR && error != ERESTART) {
670 			m_freem(*mp);
671 			*mp = NULL;
672 			if (error != EPIPE)
673 				log(LOG_INFO,
674 				    "receive error %d from nfs server %s\n",
675 				    error,
676 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
677 			error = nfs_sndlock(&rep->r_nmp->nm_flag, rep);
678 			if (!error) {
679 				error = nfs_reconnect(rep);
680 				if (!error)
681 					goto tryagain;
682 				nfs_sndunlock(&rep->r_nmp->nm_flag);
683 			}
684 		}
685 	} else {
686 		if ((so = rep->r_nmp->nm_so) == NULL)
687 			return (EACCES);
688 		if (so->so_state & SS_ISCONNECTED)
689 			getnam = NULL;
690 		else
691 			getnam = aname;
692 		auio.uio_resid = len = 1000000;
693 		auio.uio_procp = p;
694 		do {
695 			rcvflg = 0;
696 			error =  soreceive(so, getnam, &auio, mp, NULL,
697 			    &rcvflg, 0);
698 			if (error == EWOULDBLOCK &&
699 			    (rep->r_flags & R_SOFTTERM))
700 				return (EINTR);
701 		} while (error == EWOULDBLOCK);
702 		len -= auio.uio_resid;
703 	}
704 	if (error) {
705 		m_freem(*mp);
706 		*mp = NULL;
707 	}
708 	/*
709 	 * Search for any mbufs that are not a multiple of 4 bytes long
710 	 * or with m_data not longword aligned.
711 	 * These could cause pointer alignment problems, so copy them to
712 	 * well aligned mbufs.
713 	 */
714 	nfs_realign(mp, 5 * NFSX_UNSIGNED);
715 	return (error);
716 }
717 
718 /*
719  * Implement receipt of reply on a socket.
720  * We must search through the list of received datagrams matching them
721  * with outstanding requests using the xid, until ours is found.
722  */
723 int
724 nfs_reply(struct nfsreq *myrep)
725 {
726 	struct nfsreq *rep;
727 	struct nfsmount *nmp = myrep->r_nmp;
728 	struct nfsm_info	info;
729 	struct mbuf *nam;
730 	u_int32_t rxid, *tl, t1;
731 	caddr_t cp2;
732 	int s, error;
733 
734 	/*
735 	 * Loop around until we get our own reply
736 	 */
737 	for (;;) {
738 		/*
739 		 * Lock against other receivers so that I don't get stuck in
740 		 * sbwait() after someone else has received my reply for me.
741 		 * Also necessary for connection based protocols to avoid
742 		 * race conditions during a reconnect.
743 		 */
744 		error = nfs_rcvlock(myrep);
745 		if (error)
746 			return (error == EALREADY ? 0 : error);
747 
748 		/*
749 		 * Get the next Rpc reply off the socket
750 		 */
751 		error = nfs_receive(myrep, &nam, &info.nmi_mrep);
752 		nfs_rcvunlock(&nmp->nm_flag);
753 		if (error) {
754 
755 			/*
756 			 * Ignore routing errors on connectionless protocols??
757 			 */
758 			if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
759 				if (nmp->nm_so)
760 					nmp->nm_so->so_error = 0;
761 				continue;
762 			}
763 			return (error);
764 		}
765 		if (nam)
766 			m_freem(nam);
767 
768 		/*
769 		 * Get the xid and check that it is an rpc reply
770 		 */
771 		info.nmi_md = info.nmi_mrep;
772 		info.nmi_dpos = mtod(info.nmi_md, caddr_t);
773 		nfsm_dissect(tl, u_int32_t *, 2*NFSX_UNSIGNED);
774 		rxid = *tl++;
775 		if (*tl != rpc_reply) {
776 			nfsstats.rpcinvalid++;
777 			m_freem(info.nmi_mrep);
778 nfsmout:
779 			continue;
780 		}
781 
782 		/*
783 		 * Loop through the request list to match up the reply
784 		 * Iff no match, just drop the datagram
785 		 */
786 		s = splsoftnet();
787 		TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
788 			if (rep->r_mrep == NULL && rxid == rep->r_xid) {
789 				/* Found it.. */
790 				rep->r_mrep = info.nmi_mrep;
791 				rep->r_md = info.nmi_md;
792 				rep->r_dpos = info.nmi_dpos;
793 
794 				/*
795 				 * Update congestion window.
796 				 * Do the additive increase of
797 				 * one rpc/rtt.
798 				 */
799 				if (nmp->nm_cwnd <= nmp->nm_sent) {
800 					nmp->nm_cwnd +=
801 					   (NFS_CWNDSCALE * NFS_CWNDSCALE +
802 					   (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
803 					if (nmp->nm_cwnd > NFS_MAXCWND)
804 						nmp->nm_cwnd = NFS_MAXCWND;
805 				}
806 				rep->r_flags &= ~R_SENT;
807 				nmp->nm_sent -= NFS_CWNDSCALE;
808 
809 				if (rep->r_flags & R_TIMING)
810 					nfs_update_rtt(rep);
811 
812 				nmp->nm_timeouts = 0;
813 				break;
814 			}
815 		}
816 		splx(s);
817 		/*
818 		 * If not matched to a request, drop it.
819 		 * If it's mine, get out.
820 		 */
821 		if (rep == 0) {
822 			nfsstats.rpcunexpected++;
823 			m_freem(info.nmi_mrep);
824 		} else if (rep == myrep) {
825 			if (rep->r_mrep == NULL)
826 				panic("nfsreply nil");
827 			return (0);
828 		}
829 	}
830 }
831 
832 /*
833  * nfs_request - goes something like this
834  *	- fill in request struct
835  *	- links it into list
836  *	- calls nfs_send() for first transmit
837  *	- calls nfs_receive() to get reply
838  *	- break down rpc header and return with nfs reply pointed to
839  *	  by mrep or error
840  * nb: always frees up mreq mbuf list
841  */
842 int
843 nfs_request(struct vnode *vp, int procnum, struct nfsm_info *infop)
844 {
845 	struct mbuf *m;
846 	u_int32_t *tl;
847 	struct nfsmount *nmp;
848 	struct timeval tv;
849 	caddr_t cp2;
850 	int t1, i, s, error = 0;
851 	int trylater_delay;
852 	struct nfsreq *rep;
853 	int  mrest_len;
854 	struct nfsm_info	info;
855 
856 	rep = pool_get(&nfsreqpl, PR_WAITOK);
857 	rep->r_nmp = VFSTONFS(vp->v_mount);
858 	rep->r_vp = vp;
859 	rep->r_procp = infop->nmi_procp;
860 	rep->r_procnum = procnum;
861 
862 	mrest_len = 0;
863 	m = infop->nmi_mreq;
864 	while (m) {
865 		mrest_len += m->m_len;
866 		m = m->m_next;
867 	}
868 
869 	/* empty mbuf for AUTH_UNIX header */
870 	rep->r_mreq = m_gethdr(M_WAIT, MT_DATA);
871 	rep->r_mreq->m_next = infop->nmi_mreq;
872 	rep->r_mreq->m_pkthdr.len = mrest_len;
873 
874 	trylater_delay = NFS_MINTIMEO;
875 
876 	nmp = rep->r_nmp;
877 
878 	/* Get the RPC header with authorization. */
879 	nfsm_rpchead(rep, infop->nmi_cred, RPCAUTH_UNIX);
880 	m = rep->r_mreq;
881 
882 	/*
883 	 * For stream protocols, insert a Sun RPC Record Mark.
884 	 */
885 	if (nmp->nm_sotype == SOCK_STREAM) {
886 		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
887 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
888 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
889 	}
890 
891 tryagain:
892 	rep->r_rtt = rep->r_rexmit = 0;
893 	if (nfs_ptimers[rep->r_procnum] != NFS_DEFAULT_TIMER)
894 		rep->r_flags = R_TIMING;
895 	else
896 		rep->r_flags = 0;
897 	rep->r_mrep = NULL;
898 
899 	/*
900 	 * Do the client side RPC.
901 	 */
902 	nfsstats.rpcrequests++;
903 	/*
904 	 * Chain request into list of outstanding requests. Be sure
905 	 * to put it LAST so timer finds oldest requests first.
906 	 */
907 	s = splsoftnet();
908 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
909 		timeout_add(&nmp->nm_rtimeout, nfs_ticks);
910 	TAILQ_INSERT_TAIL(&nmp->nm_reqsq, rep, r_chain);
911 
912 	/*
913 	 * If backing off another request or avoiding congestion, don't
914 	 * send this one now but let timer do it. If not timing a request,
915 	 * do it now.
916 	 */
917 	if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
918 		(nmp->nm_flag & NFSMNT_DUMBTIMR) ||
919 		nmp->nm_sent < nmp->nm_cwnd)) {
920 		splx(s);
921 		if (nmp->nm_soflags & PR_CONNREQUIRED)
922 			error = nfs_sndlock(&nmp->nm_flag, rep);
923 		if (!error) {
924 			error = nfs_send(nmp->nm_so, nmp->nm_nam,
925 					m_copym(m, 0, M_COPYALL, M_WAIT),
926 					rep);
927 			if (nmp->nm_soflags & PR_CONNREQUIRED)
928 				nfs_sndunlock(&nmp->nm_flag);
929 		}
930 		if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
931 			nmp->nm_sent += NFS_CWNDSCALE;
932 			rep->r_flags |= R_SENT;
933 		}
934 	} else {
935 		splx(s);
936 		rep->r_rtt = -1;
937 	}
938 
939 	/*
940 	 * Wait for the reply from our send or the timer's.
941 	 */
942 	if (!error || error == EPIPE)
943 		error = nfs_reply(rep);
944 
945 	/*
946 	 * RPC done, unlink the request.
947 	 */
948 	s = splsoftnet();
949 	TAILQ_REMOVE(&nmp->nm_reqsq, rep, r_chain);
950 	if (TAILQ_EMPTY(&nmp->nm_reqsq))
951 		timeout_del(&nmp->nm_rtimeout);
952 	splx(s);
953 
954 	/*
955 	 * Decrement the outstanding request count.
956 	 */
957 	if (rep->r_flags & R_SENT) {
958 		rep->r_flags &= ~R_SENT;	/* paranoia */
959 		nmp->nm_sent -= NFS_CWNDSCALE;
960 	}
961 
962 	/*
963 	 * If there was a successful reply and a tprintf msg.
964 	 * tprintf a response.
965 	 */
966 	if (!error && (rep->r_flags & R_TPRINTFMSG))
967 		nfs_msg(rep, "is alive again");
968 	info.nmi_mrep = rep->r_mrep;
969 	info.nmi_md = rep->r_md;
970 	info.nmi_dpos = rep->r_dpos;
971 	if (error) {
972 		infop->nmi_mrep = NULL;
973 		goto nfsmout1;
974 	}
975 
976 	/*
977 	 * break down the rpc header and check if ok
978 	 */
979 	nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
980 	if (*tl++ == rpc_msgdenied) {
981 		if (*tl == rpc_mismatch)
982 			error = EOPNOTSUPP;
983 		else
984 			error = EACCES;	/* Should be EAUTH. */
985 		infop->nmi_mrep = NULL;
986 		goto nfsmout1;
987 	}
988 
989 	/*
990 	 * Since we only support RPCAUTH_UNIX atm we step over the
991 	 * reply verifer type, and in the (error) case that there really
992 	 * is any data in it, we advance over it.
993 	 */
994 	tl++;			/* Step over verifer type */
995 	i = fxdr_unsigned(int32_t, *tl);
996 	if (i > 0)
997 		nfsm_adv(nfsm_rndup(i));	/* Should not happen */
998 
999 	nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
1000 	/* 0 == ok */
1001 	if (*tl == 0) {
1002 		nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
1003 		if (*tl != 0) {
1004 			error = fxdr_unsigned(int, *tl);
1005 			if ((nmp->nm_flag & NFSMNT_NFSV3) &&
1006 			    error == NFSERR_TRYLATER) {
1007 				m_freem(info.nmi_mrep);
1008 				error = 0;
1009 				tv.tv_sec = time_second + trylater_delay;
1010 				tv.tv_usec = 0;
1011 				tsleep(&tv, PSOCK, "nfsretry", hzto(&tv));
1012 				trylater_delay *= NFS_TIMEOUTMUL;
1013 				if (trylater_delay > NFS_MAXTIMEO)
1014 					trylater_delay = NFS_MAXTIMEO;
1015 
1016 				goto tryagain;
1017 			}
1018 
1019 			/*
1020 			 * If the File Handle was stale, invalidate the
1021 			 * lookup cache, just in case.
1022 			 */
1023 			if (error == ESTALE)
1024 				cache_purge(rep->r_vp);
1025 		}
1026 		goto nfsmout;
1027 	}
1028 
1029 	error = EPROTONOSUPPORT;
1030 
1031 nfsmout:
1032 	infop->nmi_mrep = info.nmi_mrep;
1033 	infop->nmi_md = info.nmi_md;
1034 	infop->nmi_dpos = info.nmi_dpos;
1035 nfsmout1:
1036 	m_freem(rep->r_mreq);
1037 	pool_put(&nfsreqpl, rep);
1038 	return (error);
1039 }
1040 #endif /* NFSCLIENT */
1041 
1042 /*
1043  * Generate the rpc reply header
1044  * siz arg. is used to decide if adding a cluster is worthwhile
1045  */
1046 int
1047 nfs_rephead(int siz, struct nfsrv_descript *nd, struct nfssvc_sock *slp,
1048     int err, struct mbuf **mrq, struct mbuf **mbp)
1049 {
1050 	u_int32_t *tl;
1051 	struct mbuf *mreq;
1052 	struct mbuf *mb;
1053 
1054 	MGETHDR(mreq, M_WAIT, MT_DATA);
1055 	mb = mreq;
1056 	/*
1057 	 * If this is a big reply, use a cluster else
1058 	 * try and leave leading space for the lower level headers.
1059 	 */
1060 	siz += RPC_REPLYSIZ;
1061 	if (siz >= MHLEN - max_hdr) {
1062 		MCLGET(mreq, M_WAIT);
1063 	} else
1064 		mreq->m_data += max_hdr;
1065 	tl = mtod(mreq, u_int32_t *);
1066 	mreq->m_len = 6 * NFSX_UNSIGNED;
1067 	*tl++ = txdr_unsigned(nd->nd_retxid);
1068 	*tl++ = rpc_reply;
1069 	if (err == ERPCMISMATCH || (err & NFSERR_AUTHERR)) {
1070 		*tl++ = rpc_msgdenied;
1071 		if (err & NFSERR_AUTHERR) {
1072 			*tl++ = rpc_autherr;
1073 			*tl = txdr_unsigned(err & ~NFSERR_AUTHERR);
1074 			mreq->m_len -= NFSX_UNSIGNED;
1075 		} else {
1076 			*tl++ = rpc_mismatch;
1077 			*tl++ = txdr_unsigned(RPC_VER2);
1078 			*tl = txdr_unsigned(RPC_VER2);
1079 		}
1080 	} else {
1081 		*tl++ = rpc_msgaccepted;
1082 
1083 		/* AUTH_UNIX requires RPCAUTH_NULL. */
1084 		*tl++ = 0;
1085 		*tl++ = 0;
1086 
1087 		switch (err) {
1088 		case EPROGUNAVAIL:
1089 			*tl = txdr_unsigned(RPC_PROGUNAVAIL);
1090 			break;
1091 		case EPROGMISMATCH:
1092 			*tl = txdr_unsigned(RPC_PROGMISMATCH);
1093 			tl = nfsm_build(&mb, 2 * NFSX_UNSIGNED);
1094 			*tl++ = txdr_unsigned(NFS_VER2);
1095 			*tl = txdr_unsigned(NFS_VER3);
1096 			break;
1097 		case EPROCUNAVAIL:
1098 			*tl = txdr_unsigned(RPC_PROCUNAVAIL);
1099 			break;
1100 		case EBADRPC:
1101 			*tl = txdr_unsigned(RPC_GARBAGE);
1102 			break;
1103 		default:
1104 			*tl = 0;
1105 			if (err != NFSERR_RETVOID) {
1106 				tl = nfsm_build(&mb, NFSX_UNSIGNED);
1107 				if (err)
1108 				    *tl = txdr_unsigned(nfsrv_errmap(nd, err));
1109 				else
1110 				    *tl = 0;
1111 			}
1112 			break;
1113 		};
1114 	}
1115 
1116 	*mrq = mreq;
1117 	if (mbp != NULL)
1118 		*mbp = mb;
1119 	if (err != 0 && err != NFSERR_RETVOID)
1120 		nfsstats.srvrpc_errs++;
1121 	return (0);
1122 }
1123 
1124 /*
1125  * nfs timer routine
1126  * Scan the nfsreq list and retranmit any requests that have timed out.
1127  */
1128 void
1129 nfs_timer(void *arg)
1130 {
1131 	struct nfsmount *nmp = arg;
1132 	struct nfsreq *rep;
1133 	struct mbuf *m;
1134 	struct socket *so;
1135 	int timeo, s, error;
1136 
1137 	s = splsoftnet();
1138 	TAILQ_FOREACH(rep, &nmp->nm_reqsq, r_chain) {
1139 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM))
1140 			continue;
1141 		if (nfs_sigintr(nmp, rep, rep->r_procp)) {
1142 			rep->r_flags |= R_SOFTTERM;
1143 			continue;
1144 		}
1145 		if (rep->r_rtt >= 0) {
1146 			rep->r_rtt++;
1147 			if (nmp->nm_flag & NFSMNT_DUMBTIMR)
1148 				timeo = nmp->nm_timeo;
1149 			else
1150 				timeo = nfs_estimate_rto(nmp, rep->r_procnum);
1151 			if (nmp->nm_timeouts > 0)
1152 				timeo *= nfs_backoff[nmp->nm_timeouts - 1];
1153 			if (rep->r_rtt <= timeo)
1154 				continue;
1155 			if (nmp->nm_timeouts < nitems(nfs_backoff))
1156 				nmp->nm_timeouts++;
1157 		}
1158 
1159 		/* Check for server not responding. */
1160 		if ((rep->r_flags & R_TPRINTFMSG) == 0 && rep->r_rexmit > 4) {
1161 			nfs_msg(rep, "not responding");
1162 			rep->r_flags |= R_TPRINTFMSG;
1163 		}
1164 		if (rep->r_rexmit >= nmp->nm_retry) {	/* too many */
1165 			nfsstats.rpctimeouts++;
1166 			rep->r_flags |= R_SOFTTERM;
1167 			continue;
1168 		}
1169 		if (nmp->nm_sotype != SOCK_DGRAM) {
1170 			if (++rep->r_rexmit > NFS_MAXREXMIT)
1171 				rep->r_rexmit = NFS_MAXREXMIT;
1172 			continue;
1173 		}
1174 
1175 		if ((so = nmp->nm_so) == NULL)
1176 			continue;
1177 
1178 		/*
1179 		 * If there is enough space and the window allows..
1180 		 *	Resend it
1181 		 * Set r_rtt to -1 in case we fail to send it now.
1182 		 */
1183 		rep->r_rtt = -1;
1184 		if (sbspace(&so->so_snd) >= rep->r_mreq->m_pkthdr.len &&
1185 		   ((nmp->nm_flag & NFSMNT_DUMBTIMR) ||
1186 		    (rep->r_flags & R_SENT) ||
1187 		    nmp->nm_sent < nmp->nm_cwnd) &&
1188 		   (m = m_copym(rep->r_mreq, 0, M_COPYALL, M_DONTWAIT))){
1189 			if ((nmp->nm_flag & NFSMNT_NOCONN) == 0)
1190 			    error = (*so->so_proto->pr_usrreq)(so, PRU_SEND, m,
1191 			    NULL, NULL, curproc);
1192 			else
1193 			    error = (*so->so_proto->pr_usrreq)(so, PRU_SEND, m,
1194 			    nmp->nm_nam, NULL, curproc);
1195 			if (error) {
1196 				if (NFSIGNORE_SOERROR(nmp->nm_soflags, error))
1197 					so->so_error = 0;
1198 			} else {
1199 				/*
1200 				 * Iff first send, start timing
1201 				 * else turn timing off, backoff timer
1202 				 * and divide congestion window by 2.
1203 				 */
1204 				if (rep->r_flags & R_SENT) {
1205 					rep->r_flags &= ~R_TIMING;
1206 					if (++rep->r_rexmit > NFS_MAXREXMIT)
1207 						rep->r_rexmit = NFS_MAXREXMIT;
1208 					nmp->nm_cwnd >>= 1;
1209 					if (nmp->nm_cwnd < NFS_CWNDSCALE)
1210 						nmp->nm_cwnd = NFS_CWNDSCALE;
1211 					nfsstats.rpcretries++;
1212 				} else {
1213 					rep->r_flags |= R_SENT;
1214 					nmp->nm_sent += NFS_CWNDSCALE;
1215 				}
1216 				rep->r_rtt = 0;
1217 			}
1218 		}
1219 	}
1220 	splx(s);
1221 	timeout_add(&nmp->nm_rtimeout, nfs_ticks);
1222 }
1223 
1224 /*
1225  * Test for a termination condition pending on the process.
1226  * This is used for NFSMNT_INT mounts.
1227  */
1228 int
1229 nfs_sigintr(struct nfsmount *nmp, struct nfsreq *rep, struct proc *p)
1230 {
1231 
1232 	if (rep && (rep->r_flags & R_SOFTTERM))
1233 		return (EINTR);
1234 	if (!(nmp->nm_flag & NFSMNT_INT))
1235 		return (0);
1236 	if (p && p->p_siglist &&
1237 	    (((p->p_siglist & ~p->p_sigmask) &
1238 	    ~p->p_p->ps_sigacts->ps_sigignore) & NFSINT_SIGMASK))
1239 		return (EINTR);
1240 	return (0);
1241 }
1242 
1243 /*
1244  * Lock a socket against others.
1245  * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
1246  * and also to avoid race conditions between the processes with nfs requests
1247  * in progress when a reconnect is necessary.
1248  */
1249 int
1250 nfs_sndlock(int *flagp, struct nfsreq *rep)
1251 {
1252 	struct proc *p;
1253 	int slpflag = 0, slptimeo = 0;
1254 
1255 	if (rep) {
1256 		p = rep->r_procp;
1257 		if (rep->r_nmp->nm_flag & NFSMNT_INT)
1258 			slpflag = PCATCH;
1259 	} else
1260 		p = NULL;
1261 	while (*flagp & NFSMNT_SNDLOCK) {
1262 		if (rep && nfs_sigintr(rep->r_nmp, rep, p))
1263 			return (EINTR);
1264 		*flagp |= NFSMNT_WANTSND;
1265 		(void) tsleep((caddr_t)flagp, slpflag | (PZERO - 1), "nfsndlck",
1266 			slptimeo);
1267 		if (slpflag == PCATCH) {
1268 			slpflag = 0;
1269 			slptimeo = 2 * hz;
1270 		}
1271 	}
1272 	*flagp |= NFSMNT_SNDLOCK;
1273 	return (0);
1274 }
1275 
1276 /*
1277  * Unlock the stream socket for others.
1278  */
1279 void
1280 nfs_sndunlock(int *flagp)
1281 {
1282 
1283 	if ((*flagp & NFSMNT_SNDLOCK) == 0)
1284 		panic("nfs sndunlock");
1285 	*flagp &= ~NFSMNT_SNDLOCK;
1286 	if (*flagp & NFSMNT_WANTSND) {
1287 		*flagp &= ~NFSMNT_WANTSND;
1288 		wakeup((caddr_t)flagp);
1289 	}
1290 }
1291 
1292 int
1293 nfs_rcvlock(struct nfsreq *rep)
1294 {
1295 	int *flagp = &rep->r_nmp->nm_flag;
1296 	int slpflag, slptimeo = 0;
1297 
1298 	if (*flagp & NFSMNT_INT)
1299 		slpflag = PCATCH;
1300 	else
1301 		slpflag = 0;
1302 
1303 	while (*flagp & NFSMNT_RCVLOCK) {
1304 		if (nfs_sigintr(rep->r_nmp, rep, rep->r_procp))
1305 			return (EINTR);
1306 		*flagp |= NFSMNT_WANTRCV;
1307 		(void) tsleep((caddr_t)flagp, slpflag | (PZERO - 1), "nfsrcvlk",
1308 			slptimeo);
1309 		if (rep->r_mrep != NULL) {
1310 			/*
1311 			 * Don't take the lock if our reply has been received
1312 			 * while we where sleeping.
1313 			 */
1314 			 return (EALREADY);
1315 		}
1316 		if (slpflag == PCATCH) {
1317 			slpflag = 0;
1318 			slptimeo = 2 * hz;
1319 		}
1320 	}
1321 	*flagp |= NFSMNT_RCVLOCK;
1322 	return (0);
1323 }
1324 
1325 /*
1326  * Unlock the stream socket for others.
1327  */
1328 void
1329 nfs_rcvunlock(int *flagp)
1330 {
1331 
1332 	if ((*flagp & NFSMNT_RCVLOCK) == 0)
1333 		panic("nfs rcvunlock");
1334 	*flagp &= ~NFSMNT_RCVLOCK;
1335 	if (*flagp & NFSMNT_WANTRCV) {
1336 		*flagp &= ~NFSMNT_WANTRCV;
1337 		wakeup((caddr_t)flagp);
1338 	}
1339 }
1340 
1341 /*
1342  * Auxiliary routine to align the length of mbuf copies made with m_copyback().
1343  */
1344 void
1345 nfs_realign_fixup(struct mbuf *m, struct mbuf *n, unsigned int *off)
1346 {
1347 	size_t padding;
1348 
1349 	/*
1350 	 * The maximum number of bytes that m_copyback() places in a mbuf is
1351 	 * always an aligned quantity, so realign happens at the chain's tail.
1352 	 */
1353 	while (n->m_next != NULL)
1354 		n = n->m_next;
1355 
1356 	/*
1357 	 * Pad from the next elements in the source chain. Loop until the
1358 	 * destination chain is aligned, or the end of the source is reached.
1359 	 */
1360 	do {
1361 		m = m->m_next;
1362 		if (m == NULL)
1363 			return;
1364 
1365 		padding = min(ALIGN(n->m_len) - n->m_len, m->m_len);
1366 		if (padding > M_TRAILINGSPACE(n))
1367 			panic("nfs_realign_fixup: no memory to pad to");
1368 
1369 		bcopy(mtod(m, void *), mtod(n, char *) + n->m_len, padding);
1370 
1371 		n->m_len += padding;
1372 		m_adj(m, padding);
1373 		*off += padding;
1374 
1375 	} while (!ALIGNED_POINTER(n->m_len, void *));
1376 }
1377 
1378 /*
1379  * The NFS RPC parsing code uses the data address and the length of mbuf
1380  * structures to calculate on-memory addresses. This function makes sure these
1381  * parameters are correctly aligned.
1382  */
1383 void
1384 nfs_realign(struct mbuf **pm, int hsiz)
1385 {
1386 	struct mbuf *m;
1387 	struct mbuf *n = NULL;
1388 	unsigned int off = 0;
1389 
1390 	++nfs_realign_test;
1391 	while ((m = *pm) != NULL) {
1392 		if (!ALIGNED_POINTER(m->m_data, void *) ||
1393 		    !ALIGNED_POINTER(m->m_len,  void *)) {
1394 			MGET(n, M_WAIT, MT_DATA);
1395 #define ALIGN_POINTER(n) ((u_int)(((n) + sizeof(void *)) & ~sizeof(void *)))
1396 			if (ALIGN_POINTER(m->m_len) >= MINCLSIZE) {
1397 				MCLGET(n, M_WAIT);
1398 			}
1399 			n->m_len = 0;
1400 			break;
1401 		}
1402 		pm = &m->m_next;
1403 	}
1404 	/*
1405 	 * If n is non-NULL, loop on m copying data, then replace the
1406 	 * portion of the chain that had to be realigned.
1407 	 */
1408 	if (n != NULL) {
1409 		++nfs_realign_count;
1410 		while (m) {
1411 			m_copyback(n, off, m->m_len, mtod(m, caddr_t), M_WAIT);
1412 
1413 			/*
1414 			 * If an unaligned amount of memory was copied, fix up
1415 			 * the last mbuf created by m_copyback().
1416 			 */
1417 			if (!ALIGNED_POINTER(m->m_len, void *))
1418 				nfs_realign_fixup(m, n, &off);
1419 
1420 			off += m->m_len;
1421 			m = m->m_next;
1422 		}
1423 		m_freem(*pm);
1424 		*pm = n;
1425 	}
1426 }
1427 
1428 
1429 /*
1430  * Parse an RPC request
1431  * - verify it
1432  * - fill in the cred struct.
1433  */
1434 int
1435 nfs_getreq(struct nfsrv_descript *nd, struct nfsd *nfsd, int has_header)
1436 {
1437 	int len, i;
1438 	u_int32_t *tl;
1439 	int32_t t1;
1440 	caddr_t cp2;
1441 	u_int32_t nfsvers, auth_type;
1442 	int error = 0;
1443 	struct nfsm_info	info;
1444 
1445 	info.nmi_mrep = nd->nd_mrep;
1446 	info.nmi_md = nd->nd_md;
1447 	info.nmi_dpos = nd->nd_dpos;
1448 	if (has_header) {
1449 		nfsm_dissect(tl, u_int32_t *, 10 * NFSX_UNSIGNED);
1450 		nd->nd_retxid = fxdr_unsigned(u_int32_t, *tl++);
1451 		if (*tl++ != rpc_call) {
1452 			m_freem(info.nmi_mrep);
1453 			return (EBADRPC);
1454 		}
1455 	} else
1456 		nfsm_dissect(tl, u_int32_t *, 8 * NFSX_UNSIGNED);
1457 	nd->nd_repstat = 0;
1458 	nd->nd_flag = 0;
1459 	if (*tl++ != rpc_vers) {
1460 		nd->nd_repstat = ERPCMISMATCH;
1461 		nd->nd_procnum = NFSPROC_NOOP;
1462 		return (0);
1463 	}
1464 	if (*tl != nfs_prog) {
1465 		nd->nd_repstat = EPROGUNAVAIL;
1466 		nd->nd_procnum = NFSPROC_NOOP;
1467 		return (0);
1468 	}
1469 	tl++;
1470 	nfsvers = fxdr_unsigned(u_int32_t, *tl++);
1471 	if (nfsvers != NFS_VER2 && nfsvers != NFS_VER3) {
1472 		nd->nd_repstat = EPROGMISMATCH;
1473 		nd->nd_procnum = NFSPROC_NOOP;
1474 		return (0);
1475 	}
1476 	if (nfsvers == NFS_VER3)
1477 		nd->nd_flag = ND_NFSV3;
1478 	nd->nd_procnum = fxdr_unsigned(u_int32_t, *tl++);
1479 	if (nd->nd_procnum == NFSPROC_NULL)
1480 		return (0);
1481 	if (nd->nd_procnum >= NFS_NPROCS ||
1482 		(nd->nd_procnum > NFSPROC_COMMIT) ||
1483 		(!nd->nd_flag && nd->nd_procnum > NFSV2PROC_STATFS)) {
1484 		nd->nd_repstat = EPROCUNAVAIL;
1485 		nd->nd_procnum = NFSPROC_NOOP;
1486 		return (0);
1487 	}
1488 	if ((nd->nd_flag & ND_NFSV3) == 0)
1489 		nd->nd_procnum = nfsv3_procid[nd->nd_procnum];
1490 	auth_type = *tl++;
1491 	len = fxdr_unsigned(int, *tl++);
1492 	if (len < 0 || len > RPCAUTH_MAXSIZ) {
1493 		m_freem(info.nmi_mrep);
1494 		return (EBADRPC);
1495 	}
1496 
1497 	/* Handle auth_unix */
1498 	if (auth_type == rpc_auth_unix) {
1499 		len = fxdr_unsigned(int, *++tl);
1500 		if (len < 0 || len > NFS_MAXNAMLEN) {
1501 			m_freem(info.nmi_mrep);
1502 			return (EBADRPC);
1503 		}
1504 		nfsm_adv(nfsm_rndup(len));
1505 		nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
1506 		memset(&nd->nd_cr, 0, sizeof (struct ucred));
1507 		nd->nd_cr.cr_ref = 1;
1508 		nd->nd_cr.cr_uid = fxdr_unsigned(uid_t, *tl++);
1509 		nd->nd_cr.cr_gid = fxdr_unsigned(gid_t, *tl++);
1510 		len = fxdr_unsigned(int, *tl);
1511 		if (len < 0 || len > RPCAUTH_UNIXGIDS) {
1512 			m_freem(info.nmi_mrep);
1513 			return (EBADRPC);
1514 		}
1515 		nfsm_dissect(tl, u_int32_t *, (len + 2) * NFSX_UNSIGNED);
1516 		for (i = 0; i < len; i++)
1517 		    if (i < NGROUPS)
1518 			nd->nd_cr.cr_groups[i] = fxdr_unsigned(gid_t, *tl++);
1519 		    else
1520 			tl++;
1521 		nd->nd_cr.cr_ngroups = (len > NGROUPS) ? NGROUPS : len;
1522 		len = fxdr_unsigned(int, *++tl);
1523 		if (len < 0 || len > RPCAUTH_MAXSIZ) {
1524 			m_freem(info.nmi_mrep);
1525 			return (EBADRPC);
1526 		}
1527 		if (len > 0)
1528 			nfsm_adv(nfsm_rndup(len));
1529 	} else {
1530 		nd->nd_repstat = (NFSERR_AUTHERR | AUTH_REJECTCRED);
1531 		nd->nd_procnum = NFSPROC_NOOP;
1532 		return (0);
1533 	}
1534 
1535 	nd->nd_md = info.nmi_md;
1536 	nd->nd_dpos = info.nmi_dpos;
1537 	return (0);
1538 nfsmout:
1539 	return (error);
1540 }
1541 
1542 void
1543 nfs_msg(struct nfsreq *rep, char *msg)
1544 {
1545 	tpr_t tpr;
1546 
1547 	if (rep->r_procp)
1548 		tpr = tprintf_open(rep->r_procp);
1549 	else
1550 		tpr = NULL;
1551 
1552 	tprintf(tpr, "nfs server %s: %s\n",
1553 	    rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname, msg);
1554 	tprintf_close(tpr);
1555 }
1556 
1557 #ifdef NFSSERVER
1558 /*
1559  * Socket upcall routine for the nfsd sockets.
1560  * The caddr_t arg is a pointer to the "struct nfssvc_sock".
1561  * Essentially do as much as possible non-blocking, else punt and it will
1562  * be called with M_WAIT from an nfsd.
1563  */
1564 void
1565 nfsrv_rcv(struct socket *so, caddr_t arg, int waitflag)
1566 {
1567 	struct nfssvc_sock *slp = (struct nfssvc_sock *)arg;
1568 	struct mbuf *m;
1569 	struct mbuf *mp, *nam;
1570 	struct uio auio;
1571 	int flags, error;
1572 
1573 	if ((slp->ns_flag & SLP_VALID) == 0)
1574 		return;
1575 #ifdef notdef
1576 	/*
1577 	 * Define this to test for nfsds handling this under heavy load.
1578 	 */
1579 	if (waitflag == M_DONTWAIT) {
1580 		slp->ns_flag |= SLP_NEEDQ; goto dorecs;
1581 	}
1582 #endif
1583 	auio.uio_procp = NULL;
1584 	if (so->so_type == SOCK_STREAM) {
1585 		/*
1586 		 * If there are already records on the queue, defer soreceive()
1587 		 * to an nfsd so that there is feedback to the TCP layer that
1588 		 * the nfs servers are heavily loaded.
1589 		 */
1590 		if (slp->ns_rec && waitflag == M_DONTWAIT) {
1591 			slp->ns_flag |= SLP_NEEDQ;
1592 			goto dorecs;
1593 		}
1594 
1595 		/*
1596 		 * Do soreceive().
1597 		 */
1598 		auio.uio_resid = 1000000000;
1599 		flags = MSG_DONTWAIT;
1600 		error = soreceive(so, &nam, &auio, &mp, NULL,
1601 		    &flags, 0);
1602 		if (error || mp == NULL) {
1603 			if (error == EWOULDBLOCK)
1604 				slp->ns_flag |= SLP_NEEDQ;
1605 			else
1606 				slp->ns_flag |= SLP_DISCONN;
1607 			goto dorecs;
1608 		}
1609 		m = mp;
1610 		if (slp->ns_rawend) {
1611 			slp->ns_rawend->m_next = m;
1612 			slp->ns_cc += 1000000000 - auio.uio_resid;
1613 		} else {
1614 			slp->ns_raw = m;
1615 			slp->ns_cc = 1000000000 - auio.uio_resid;
1616 		}
1617 		while (m->m_next)
1618 			m = m->m_next;
1619 		slp->ns_rawend = m;
1620 
1621 		/*
1622 		 * Now try and parse record(s) out of the raw stream data.
1623 		 */
1624 		error = nfsrv_getstream(slp, waitflag);
1625 		if (error) {
1626 			if (error == EPERM)
1627 				slp->ns_flag |= SLP_DISCONN;
1628 			else
1629 				slp->ns_flag |= SLP_NEEDQ;
1630 		}
1631 	} else {
1632 		do {
1633 			auio.uio_resid = 1000000000;
1634 			flags = MSG_DONTWAIT;
1635 			error = soreceive(so, &nam, &auio, &mp,
1636 			    NULL, &flags, 0);
1637 			if (mp) {
1638 				if (nam) {
1639 					m = nam;
1640 					m->m_next = mp;
1641 				} else
1642 					m = mp;
1643 				if (slp->ns_recend)
1644 					slp->ns_recend->m_nextpkt = m;
1645 				else
1646 					slp->ns_rec = m;
1647 				slp->ns_recend = m;
1648 				m->m_nextpkt = NULL;
1649 			}
1650 			if (error) {
1651 				if ((so->so_proto->pr_flags & PR_CONNREQUIRED)
1652 					&& error != EWOULDBLOCK) {
1653 					slp->ns_flag |= SLP_DISCONN;
1654 					goto dorecs;
1655 				}
1656 			}
1657 		} while (mp);
1658 	}
1659 
1660 	/*
1661 	 * Now try and process the request records, non-blocking.
1662 	 */
1663 dorecs:
1664 	if (waitflag == M_DONTWAIT &&
1665 		(slp->ns_rec || (slp->ns_flag & (SLP_NEEDQ | SLP_DISCONN))))
1666 		nfsrv_wakenfsd(slp);
1667 }
1668 
1669 /*
1670  * Try and extract an RPC request from the mbuf data list received on a
1671  * stream socket. The "waitflag" argument indicates whether or not it
1672  * can sleep.
1673  */
1674 int
1675 nfsrv_getstream(struct nfssvc_sock *slp, int waitflag)
1676 {
1677 	struct mbuf *m, **mpp;
1678 	char *cp1, *cp2;
1679 	int len;
1680 	struct mbuf *om, *m2, *recm;
1681 	u_int32_t recmark;
1682 
1683 	if (slp->ns_flag & SLP_GETSTREAM)
1684 		return (0);
1685 	slp->ns_flag |= SLP_GETSTREAM;
1686 	for (;;) {
1687 	    if (slp->ns_reclen == 0) {
1688 		if (slp->ns_cc < NFSX_UNSIGNED) {
1689 			slp->ns_flag &= ~SLP_GETSTREAM;
1690 			return (0);
1691 		}
1692 		m = slp->ns_raw;
1693 		if (m->m_len >= NFSX_UNSIGNED) {
1694 			bcopy(mtod(m, caddr_t), (caddr_t)&recmark, NFSX_UNSIGNED);
1695 			m->m_data += NFSX_UNSIGNED;
1696 			m->m_len -= NFSX_UNSIGNED;
1697 		} else {
1698 			cp1 = (caddr_t)&recmark;
1699 			cp2 = mtod(m, caddr_t);
1700 			while (cp1 < ((caddr_t)&recmark) + NFSX_UNSIGNED) {
1701 				while (m->m_len == 0) {
1702 					m = m->m_next;
1703 					cp2 = mtod(m, caddr_t);
1704 				}
1705 				*cp1++ = *cp2++;
1706 				m->m_data++;
1707 				m->m_len--;
1708 			}
1709 		}
1710 		slp->ns_cc -= NFSX_UNSIGNED;
1711 		recmark = ntohl(recmark);
1712 		slp->ns_reclen = recmark & ~0x80000000;
1713 		if (recmark & 0x80000000)
1714 			slp->ns_flag |= SLP_LASTFRAG;
1715 		else
1716 			slp->ns_flag &= ~SLP_LASTFRAG;
1717 		if (slp->ns_reclen > NFS_MAXPACKET) {
1718 			slp->ns_flag &= ~SLP_GETSTREAM;
1719 			return (EPERM);
1720 		}
1721 	    }
1722 
1723 	    /*
1724 	     * Now get the record part.
1725 	     */
1726 	    recm = NULL;
1727 	    if (slp->ns_cc == slp->ns_reclen) {
1728 		recm = slp->ns_raw;
1729 		slp->ns_raw = slp->ns_rawend = NULL;
1730 		slp->ns_cc = slp->ns_reclen = 0;
1731 	    } else if (slp->ns_cc > slp->ns_reclen) {
1732 		len = 0;
1733 		m = slp->ns_raw;
1734 		om = NULL;
1735 		while (len < slp->ns_reclen) {
1736 			if ((len + m->m_len) > slp->ns_reclen) {
1737 				m2 = m_copym(m, 0, slp->ns_reclen - len,
1738 					waitflag);
1739 				if (m2) {
1740 					if (om) {
1741 						om->m_next = m2;
1742 						recm = slp->ns_raw;
1743 					} else
1744 						recm = m2;
1745 					m->m_data += slp->ns_reclen - len;
1746 					m->m_len -= slp->ns_reclen - len;
1747 					len = slp->ns_reclen;
1748 				} else {
1749 					slp->ns_flag &= ~SLP_GETSTREAM;
1750 					return (EWOULDBLOCK);
1751 				}
1752 			} else if ((len + m->m_len) == slp->ns_reclen) {
1753 				om = m;
1754 				len += m->m_len;
1755 				m = m->m_next;
1756 				recm = slp->ns_raw;
1757 				om->m_next = NULL;
1758 			} else {
1759 				om = m;
1760 				len += m->m_len;
1761 				m = m->m_next;
1762 			}
1763 		}
1764 		slp->ns_raw = m;
1765 		slp->ns_cc -= len;
1766 		slp->ns_reclen = 0;
1767 	    } else {
1768 		slp->ns_flag &= ~SLP_GETSTREAM;
1769 		return (0);
1770 	    }
1771 
1772 	    /*
1773 	     * Accumulate the fragments into a record.
1774 	     */
1775 	    mpp = &slp->ns_frag;
1776 	    while (*mpp)
1777 		mpp = &((*mpp)->m_next);
1778 	    *mpp = recm;
1779 	    if (slp->ns_flag & SLP_LASTFRAG) {
1780 		if (slp->ns_recend)
1781 		    slp->ns_recend->m_nextpkt = slp->ns_frag;
1782 		else
1783 		    slp->ns_rec = slp->ns_frag;
1784 		slp->ns_recend = slp->ns_frag;
1785 		slp->ns_frag = NULL;
1786 	    }
1787 	}
1788 }
1789 
1790 /*
1791  * Parse an RPC header.
1792  */
1793 int
1794 nfsrv_dorec(struct nfssvc_sock *slp, struct nfsd *nfsd,
1795     struct nfsrv_descript **ndp)
1796 {
1797 	struct mbuf *m, *nam;
1798 	struct nfsrv_descript *nd;
1799 	int error;
1800 
1801 	*ndp = NULL;
1802 	if ((slp->ns_flag & SLP_VALID) == 0 ||
1803 	    (m = slp->ns_rec) == NULL)
1804 		return (ENOBUFS);
1805 	slp->ns_rec = m->m_nextpkt;
1806 	if (slp->ns_rec)
1807 		m->m_nextpkt = NULL;
1808 	else
1809 		slp->ns_recend = NULL;
1810 	if (m->m_type == MT_SONAME) {
1811 		nam = m;
1812 		m = m->m_next;
1813 		nam->m_next = NULL;
1814 	} else
1815 		nam = NULL;
1816 	nd = pool_get(&nfsrv_descript_pl, PR_WAITOK);
1817 	nfs_realign(&m, 10 * NFSX_UNSIGNED);
1818 	nd->nd_md = nd->nd_mrep = m;
1819 	nd->nd_nam2 = nam;
1820 	nd->nd_dpos = mtod(m, caddr_t);
1821 	error = nfs_getreq(nd, nfsd, 1);
1822 	if (error) {
1823 		m_freem(nam);
1824 		pool_put(&nfsrv_descript_pl, nd);
1825 		return (error);
1826 	}
1827 	*ndp = nd;
1828 	nfsd->nfsd_nd = nd;
1829 	return (0);
1830 }
1831 
1832 
1833 /*
1834  * Search for a sleeping nfsd and wake it up.
1835  * SIDE EFFECT: If none found, set NFSD_CHECKSLP flag, so that one of the
1836  * running nfsds will go look for the work in the nfssvc_sock list.
1837  */
1838 void
1839 nfsrv_wakenfsd(struct nfssvc_sock *slp)
1840 {
1841 	struct nfsd	*nfsd;
1842 
1843 	if ((slp->ns_flag & SLP_VALID) == 0)
1844 		return;
1845 
1846 	TAILQ_FOREACH(nfsd, &nfsd_head, nfsd_chain) {
1847 		if (nfsd->nfsd_flag & NFSD_WAITING) {
1848 			nfsd->nfsd_flag &= ~NFSD_WAITING;
1849 			if (nfsd->nfsd_slp)
1850 				panic("nfsd wakeup");
1851 			slp->ns_sref++;
1852 			nfsd->nfsd_slp = slp;
1853 			wakeup_one(nfsd);
1854 			return;
1855 		}
1856 	}
1857 
1858 	slp->ns_flag |= SLP_DOREC;
1859 	nfsd_head_flag |= NFSD_CHECKSLP;
1860 }
1861 #endif /* NFSSERVER */
1862