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nfs_clntsocket.c revision 1.6
      1 /*	$NetBSD: nfs_clntsocket.c,v 1.6 2018/01/21 20:36:49 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1991, 1993, 1995
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Rick Macklem at The University of Guelph.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)nfs_socket.c	8.5 (Berkeley) 3/30/95
     35  */
     36 
     37 /*
     38  * Socket operations for use by nfs
     39  */
     40 
     41 #include <sys/cdefs.h>
     42 __KERNEL_RCSID(0, "$NetBSD: nfs_clntsocket.c,v 1.6 2018/01/21 20:36:49 christos Exp $");
     43 
     44 #ifdef _KERNEL_OPT
     45 #include "opt_nfs.h"
     46 #include "opt_mbuftrace.h"
     47 #endif
     48 
     49 #include <sys/param.h>
     50 #include <sys/systm.h>
     51 #include <sys/evcnt.h>
     52 #include <sys/callout.h>
     53 #include <sys/proc.h>
     54 #include <sys/mount.h>
     55 #include <sys/kernel.h>
     56 #include <sys/kmem.h>
     57 #include <sys/mbuf.h>
     58 #include <sys/vnode.h>
     59 #include <sys/domain.h>
     60 #include <sys/protosw.h>
     61 #include <sys/socket.h>
     62 #include <sys/socketvar.h>
     63 #include <sys/syslog.h>
     64 #include <sys/tprintf.h>
     65 #include <sys/namei.h>
     66 #include <sys/signal.h>
     67 #include <sys/signalvar.h>
     68 #include <sys/kauth.h>
     69 
     70 #include <netinet/in.h>
     71 #include <netinet/tcp.h>
     72 
     73 #include <nfs/rpcv2.h>
     74 #include <nfs/nfsproto.h>
     75 #include <nfs/nfs.h>
     76 #include <nfs/xdr_subs.h>
     77 #include <nfs/nfsm_subs.h>
     78 #include <nfs/nfsmount.h>
     79 #include <nfs/nfsnode.h>
     80 #include <nfs/nfsrtt.h>
     81 #include <nfs/nfs_var.h>
     82 
     83 static int nfs_sndlock(struct nfsmount *, struct nfsreq *);
     84 static void nfs_sndunlock(struct nfsmount *);
     85 
     86 /*
     87  * Receive a Sun RPC Request/Reply. For SOCK_DGRAM, the work is all
     88  * done by soreceive(), but for SOCK_STREAM we must deal with the Record
     89  * Mark and consolidate the data into a new mbuf list.
     90  * nb: Sometimes TCP passes the data up to soreceive() in long lists of
     91  *     small mbufs.
     92  * For SOCK_STREAM we must be very careful to read an entire record once
     93  * we have read any of it, even if the system call has been interrupted.
     94  */
     95 static int
     96 nfs_receive(struct nfsreq *rep, struct mbuf **aname, struct mbuf **mp,
     97     struct lwp *l)
     98 {
     99 	struct socket *so;
    100 	struct uio auio;
    101 	struct iovec aio;
    102 	struct mbuf *m;
    103 	struct mbuf *control;
    104 	u_int32_t len;
    105 	struct mbuf **getnam;
    106 	int error, sotype, rcvflg;
    107 
    108 	/*
    109 	 * Set up arguments for soreceive()
    110 	 */
    111 	*mp = NULL;
    112 	*aname = NULL;
    113 	sotype = rep->r_nmp->nm_sotype;
    114 
    115 	/*
    116 	 * For reliable protocols, lock against other senders/receivers
    117 	 * in case a reconnect is necessary.
    118 	 * For SOCK_STREAM, first get the Record Mark to find out how much
    119 	 * more there is to get.
    120 	 * We must lock the socket against other receivers
    121 	 * until we have an entire rpc request/reply.
    122 	 */
    123 	if (sotype != SOCK_DGRAM) {
    124 		error = nfs_sndlock(rep->r_nmp, rep);
    125 		if (error)
    126 			return (error);
    127 tryagain:
    128 		/*
    129 		 * Check for fatal errors and resending request.
    130 		 */
    131 		/*
    132 		 * Ugh: If a reconnect attempt just happened, nm_so
    133 		 * would have changed. NULL indicates a failed
    134 		 * attempt that has essentially shut down this
    135 		 * mount point.
    136 		 */
    137 		if (rep->r_mrep || (rep->r_flags & R_SOFTTERM)) {
    138 			nfs_sndunlock(rep->r_nmp);
    139 			return (EINTR);
    140 		}
    141 		so = rep->r_nmp->nm_so;
    142 		if (!so) {
    143 			error = nfs_reconnect(rep);
    144 			if (error) {
    145 				nfs_sndunlock(rep->r_nmp);
    146 				return (error);
    147 			}
    148 			goto tryagain;
    149 		}
    150 		while (rep->r_flags & R_MUSTRESEND) {
    151 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
    152 			nfsstats.rpcretries++;
    153 			rep->r_rtt = 0;
    154 			rep->r_flags &= ~R_TIMING;
    155 			error = nfs_send(so, rep->r_nmp->nm_nam, m, rep, l);
    156 			if (error) {
    157 				if (error == EINTR || error == ERESTART ||
    158 				    (error = nfs_reconnect(rep)) != 0) {
    159 					nfs_sndunlock(rep->r_nmp);
    160 					return (error);
    161 				}
    162 				goto tryagain;
    163 			}
    164 		}
    165 		nfs_sndunlock(rep->r_nmp);
    166 		if (sotype == SOCK_STREAM) {
    167 			aio.iov_base = (void *) &len;
    168 			aio.iov_len = sizeof(u_int32_t);
    169 			auio.uio_iov = &aio;
    170 			auio.uio_iovcnt = 1;
    171 			auio.uio_rw = UIO_READ;
    172 			auio.uio_offset = 0;
    173 			auio.uio_resid = sizeof(u_int32_t);
    174 			UIO_SETUP_SYSSPACE(&auio);
    175 			do {
    176 			   rcvflg = MSG_WAITALL;
    177 			   error = (*so->so_receive)(so, NULL, &auio,
    178 				NULL, NULL, &rcvflg);
    179 			   if (error == EWOULDBLOCK && rep) {
    180 				if (rep->r_flags & R_SOFTTERM)
    181 					return (EINTR);
    182 				/*
    183 				 * if it seems that the server died after it
    184 				 * received our request, set EPIPE so that
    185 				 * we'll reconnect and retransmit requests.
    186 				 */
    187 				if (rep->r_rexmit >= rep->r_nmp->nm_retry) {
    188 					nfsstats.rpctimeouts++;
    189 					error = EPIPE;
    190 				}
    191 			   }
    192 			} while (error == EWOULDBLOCK);
    193 			if (!error && auio.uio_resid > 0) {
    194 			    /*
    195 			     * Don't log a 0 byte receive; it means
    196 			     * that the socket has been closed, and
    197 			     * can happen during normal operation
    198 			     * (forcible unmount or Solaris server).
    199 			     */
    200 			    if (auio.uio_resid != sizeof (u_int32_t))
    201 			      log(LOG_INFO,
    202 				 "short receive (%lu/%lu) from nfs server %s\n",
    203 				 (u_long)sizeof(u_int32_t) - auio.uio_resid,
    204 				 (u_long)sizeof(u_int32_t),
    205 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
    206 			    error = EPIPE;
    207 			}
    208 			if (error)
    209 				goto errout;
    210 			len = ntohl(len) & ~0x80000000;
    211 			/*
    212 			 * This is SERIOUS! We are out of sync with the sender
    213 			 * and forcing a disconnect/reconnect is all I can do.
    214 			 */
    215 			if (len > NFS_MAXPACKET) {
    216 			    log(LOG_ERR, "%s (%d) from nfs server %s\n",
    217 				"impossible packet length",
    218 				len,
    219 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
    220 			    error = EFBIG;
    221 			    goto errout;
    222 			}
    223 			auio.uio_resid = len;
    224 			do {
    225 			    rcvflg = MSG_WAITALL;
    226 			    error =  (*so->so_receive)(so, NULL,
    227 				&auio, mp, NULL, &rcvflg);
    228 			} while (error == EWOULDBLOCK || error == EINTR ||
    229 				 error == ERESTART);
    230 			if (!error && auio.uio_resid > 0) {
    231 			    if (len != auio.uio_resid)
    232 			      log(LOG_INFO,
    233 				"short receive (%lu/%d) from nfs server %s\n",
    234 				(u_long)len - auio.uio_resid, len,
    235 				rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
    236 			    error = EPIPE;
    237 			}
    238 		} else {
    239 			/*
    240 			 * NB: Since uio_resid is big, MSG_WAITALL is ignored
    241 			 * and soreceive() will return when it has either a
    242 			 * control msg or a data msg.
    243 			 * We have no use for control msg., but must grab them
    244 			 * and then throw them away so we know what is going
    245 			 * on.
    246 			 */
    247 			auio.uio_resid = len = 100000000; /* Anything Big */
    248 			/* not need to setup uio_vmspace */
    249 			do {
    250 			    rcvflg = 0;
    251 			    error =  (*so->so_receive)(so, NULL,
    252 				&auio, mp, &control, &rcvflg);
    253 			    if (control)
    254 				m_freem(control);
    255 			    if (error == EWOULDBLOCK && rep) {
    256 				if (rep->r_flags & R_SOFTTERM)
    257 					return (EINTR);
    258 			    }
    259 			} while (error == EWOULDBLOCK ||
    260 				 (!error && *mp == NULL && control));
    261 			if ((rcvflg & MSG_EOR) == 0)
    262 				printf("Egad!!\n");
    263 			if (!error && *mp == NULL)
    264 				error = EPIPE;
    265 			len -= auio.uio_resid;
    266 		}
    267 errout:
    268 		if (error && error != EINTR && error != ERESTART) {
    269 			m_freem(*mp);
    270 			*mp = NULL;
    271 			if (error != EPIPE)
    272 				log(LOG_INFO,
    273 				    "receive error %d from nfs server %s\n",
    274 				    error,
    275 				 rep->r_nmp->nm_mountp->mnt_stat.f_mntfromname);
    276 			error = nfs_sndlock(rep->r_nmp, rep);
    277 			if (!error)
    278 				error = nfs_reconnect(rep);
    279 			if (!error)
    280 				goto tryagain;
    281 			else
    282 				nfs_sndunlock(rep->r_nmp);
    283 		}
    284 	} else {
    285 		if ((so = rep->r_nmp->nm_so) == NULL)
    286 			return (EACCES);
    287 		if (so->so_state & SS_ISCONNECTED)
    288 			getnam = NULL;
    289 		else
    290 			getnam = aname;
    291 		auio.uio_resid = len = 1000000;
    292 		/* not need to setup uio_vmspace */
    293 		do {
    294 			rcvflg = 0;
    295 			error =  (*so->so_receive)(so, getnam, &auio, mp,
    296 				NULL, &rcvflg);
    297 			if (error == EWOULDBLOCK) {
    298 				int intr = nfs_sigintr(rep->r_nmp, rep, l);
    299 				if (intr)
    300 					error = intr;
    301 			}
    302 		} while (error == EWOULDBLOCK);
    303 		len -= auio.uio_resid;
    304 		if (!error && *mp == NULL)
    305 			error = EPIPE;
    306 	}
    307 	if (error) {
    308 		m_freem(*mp);
    309 		*mp = NULL;
    310 	}
    311 	return (error);
    312 }
    313 
    314 /*
    315  * Implement receipt of reply on a socket.
    316  * We must search through the list of received datagrams matching them
    317  * with outstanding requests using the xid, until ours is found.
    318  */
    319 /* ARGSUSED */
    320 static int
    321 nfs_reply(struct nfsreq *myrep, struct lwp *lwp)
    322 {
    323 	struct nfsreq *rep;
    324 	struct nfsmount *nmp = myrep->r_nmp;
    325 	int32_t t1;
    326 	struct mbuf *mrep, *nam, *md;
    327 	u_int32_t rxid, *tl;
    328 	char *dpos, *cp2;
    329 	int error, s;
    330 
    331 	/*
    332 	 * Loop around until we get our own reply
    333 	 */
    334 	for (;;) {
    335 		/*
    336 		 * Lock against other receivers so that I don't get stuck in
    337 		 * sbwait() after someone else has received my reply for me.
    338 		 * Also necessary for connection based protocols to avoid
    339 		 * race conditions during a reconnect.
    340 		 */
    341 		error = nfs_rcvlock(nmp, myrep);
    342 		if (error == EALREADY)
    343 			return (0);
    344 		if (error)
    345 			return (error);
    346 		/*
    347 		 * Get the next Rpc reply off the socket
    348 		 */
    349 
    350 		mutex_enter(&nmp->nm_lock);
    351 		nmp->nm_waiters++;
    352 		mutex_exit(&nmp->nm_lock);
    353 
    354 		error = nfs_receive(myrep, &nam, &mrep, lwp);
    355 
    356 		mutex_enter(&nmp->nm_lock);
    357 		nmp->nm_waiters--;
    358 		cv_signal(&nmp->nm_disconcv);
    359 		mutex_exit(&nmp->nm_lock);
    360 
    361 		if (error) {
    362 			nfs_rcvunlock(nmp);
    363 
    364 			if (nmp->nm_iflag & NFSMNT_DISMNT) {
    365 				/*
    366 				 * Oops, we're going away now..
    367 				 */
    368 				return error;
    369 			}
    370 			/*
    371 			 * Ignore routing errors on connectionless protocols? ?
    372 			 */
    373 			if (NFSIGNORE_SOERROR(nmp->nm_soflags, error)) {
    374 				nmp->nm_so->so_error = 0;
    375 #ifdef DEBUG
    376 				if (ratecheck(&nfs_reply_last_err_time,
    377 				    &nfs_err_interval))
    378 					printf("%s: ignoring error %d\n",
    379 					       __func__, error);
    380 #endif
    381 				continue;
    382 			}
    383 			return (error);
    384 		}
    385 		if (nam)
    386 			m_freem(nam);
    387 
    388 		/*
    389 		 * Get the xid and check that it is an rpc reply
    390 		 */
    391 		md = mrep;
    392 		dpos = mtod(md, void *);
    393 		nfsm_dissect(tl, u_int32_t *, 2*NFSX_UNSIGNED);
    394 		rxid = *tl++;
    395 		if (*tl != rpc_reply) {
    396 			nfsstats.rpcinvalid++;
    397 			m_freem(mrep);
    398 nfsmout:
    399 			nfs_rcvunlock(nmp);
    400 			continue;
    401 		}
    402 
    403 		/*
    404 		 * Loop through the request list to match up the reply
    405 		 * Iff no match, just drop the datagram
    406 		 */
    407 		s = splsoftnet();
    408 		mutex_enter(&nfs_reqq_lock);
    409 		TAILQ_FOREACH(rep, &nfs_reqq, r_chain) {
    410 			if (rep->r_mrep != NULL || rxid != rep->r_xid)
    411 				continue;
    412 
    413 			/* Found it.. */
    414 			rep->r_mrep = mrep;
    415 			rep->r_md = md;
    416 			rep->r_dpos = dpos;
    417 			if (nfsrtton) {
    418 				struct rttl *rt;
    419 				int proct = nfs_proct[rep->r_procnum];
    420 
    421 				rt = &nfsrtt.rttl[nfsrtt.pos];
    422 				rt->proc = rep->r_procnum;
    423 				rt->rto = NFS_RTO(nmp, proct);
    424 				rt->sent = nmp->nm_sent;
    425 				rt->cwnd = nmp->nm_cwnd;
    426 				rt->srtt = nmp->nm_srtt[proct - 1];
    427 				rt->sdrtt = nmp->nm_sdrtt[proct - 1];
    428 				rt->fsid = nmp->nm_mountp->mnt_stat.f_fsidx;
    429 				getmicrotime(&rt->tstamp);
    430 				if (rep->r_flags & R_TIMING)
    431 					rt->rtt = rep->r_rtt;
    432 				else
    433 					rt->rtt = 1000000;
    434 				nfsrtt.pos = (nfsrtt.pos + 1) % NFSRTTLOGSIZ;
    435 			}
    436 			/*
    437 			 * Update congestion window.
    438 			 * Do the additive increase of
    439 			 * one rpc/rtt.
    440 			 */
    441 			if (nmp->nm_cwnd <= nmp->nm_sent) {
    442 				nmp->nm_cwnd +=
    443 				   (NFS_CWNDSCALE * NFS_CWNDSCALE +
    444 				   (nmp->nm_cwnd >> 1)) / nmp->nm_cwnd;
    445 				if (nmp->nm_cwnd > NFS_MAXCWND)
    446 					nmp->nm_cwnd = NFS_MAXCWND;
    447 			}
    448 			rep->r_flags &= ~R_SENT;
    449 			nmp->nm_sent -= NFS_CWNDSCALE;
    450 			/*
    451 			 * Update rtt using a gain of 0.125 on the mean
    452 			 * and a gain of 0.25 on the deviation.
    453 			 */
    454 			if (rep->r_flags & R_TIMING) {
    455 				/*
    456 				 * Since the timer resolution of
    457 				 * NFS_HZ is so course, it can often
    458 				 * result in r_rtt == 0. Since
    459 				 * r_rtt == N means that the actual
    460 				 * rtt is between N+dt and N+2-dt ticks,
    461 				 * add 1.
    462 				 */
    463 				t1 = rep->r_rtt + 1;
    464 				t1 -= (NFS_SRTT(rep) >> 3);
    465 				NFS_SRTT(rep) += t1;
    466 				if (t1 < 0)
    467 					t1 = -t1;
    468 				t1 -= (NFS_SDRTT(rep) >> 2);
    469 				NFS_SDRTT(rep) += t1;
    470 			}
    471 			nmp->nm_timeouts = 0;
    472 			break;
    473 		}
    474 		mutex_exit(&nfs_reqq_lock);
    475 		splx(s);
    476 		nfs_rcvunlock(nmp);
    477 		/*
    478 		 * If not matched to a request, drop it.
    479 		 * If it's mine, get out.
    480 		 */
    481 		if (rep == 0) {
    482 			nfsstats.rpcunexpected++;
    483 			m_freem(mrep);
    484 		} else if (rep == myrep) {
    485 			if (rep->r_mrep == NULL)
    486 				panic("nfsreply nil");
    487 			return (0);
    488 		}
    489 	}
    490 }
    491 
    492 /*
    493  * nfs_request - goes something like this
    494  *	- fill in request struct
    495  *	- links it into list
    496  *	- calls nfs_send() for first transmit
    497  *	- calls nfs_receive() to get reply
    498  *	- break down rpc header and return with nfs reply pointed to
    499  *	  by mrep or error
    500  * nb: always frees up mreq mbuf list
    501  */
    502 int
    503 nfs_request(struct nfsnode *np, struct mbuf *mrest, int procnum, struct lwp *lwp, kauth_cred_t cred, struct mbuf **mrp, struct mbuf **mdp, char **dposp, int *rexmitp)
    504 {
    505 	struct mbuf *m, *mrep;
    506 	struct nfsreq *rep;
    507 	u_int32_t *tl;
    508 	int i;
    509 	struct nfsmount *nmp = VFSTONFS(np->n_vnode->v_mount);
    510 	struct mbuf *md, *mheadend;
    511 	char nickv[RPCX_NICKVERF];
    512 	time_t waituntil;
    513 	char *dpos, *cp2;
    514 	int t1, s, error = 0, mrest_len, auth_len, auth_type;
    515 	int trylater_delay = NFS_TRYLATERDEL, failed_auth = 0;
    516 	int verf_len, verf_type;
    517 	u_int32_t xid;
    518 	char *auth_str, *verf_str;
    519 	NFSKERBKEY_T key;		/* save session key */
    520 	kauth_cred_t acred;
    521 	struct mbuf *mrest_backup = NULL;
    522 	kauth_cred_t origcred = NULL; /* XXX: gcc */
    523 	bool retry_cred = true;
    524 	bool use_opencred = (np->n_flag & NUSEOPENCRED) != 0;
    525 
    526 	if (rexmitp != NULL)
    527 		*rexmitp = 0;
    528 
    529 	acred = kauth_cred_alloc();
    530 
    531 tryagain_cred:
    532 	KASSERT(cred != NULL);
    533 	rep = kmem_alloc(sizeof(*rep), KM_SLEEP);
    534 	rep->r_nmp = nmp;
    535 	KASSERT(lwp == NULL || lwp == curlwp);
    536 	rep->r_lwp = lwp;
    537 	rep->r_procnum = procnum;
    538 	i = 0;
    539 	m = mrest;
    540 	while (m) {
    541 		i += m->m_len;
    542 		m = m->m_next;
    543 	}
    544 	mrest_len = i;
    545 
    546 	/*
    547 	 * Get the RPC header with authorization.
    548 	 */
    549 kerbauth:
    550 	verf_str = auth_str = NULL;
    551 	if (nmp->nm_flag & NFSMNT_KERB) {
    552 		verf_str = nickv;
    553 		verf_len = sizeof (nickv);
    554 		auth_type = RPCAUTH_KERB4;
    555 		memset((void *)key, 0, sizeof (key));
    556 		if (failed_auth || nfs_getnickauth(nmp, cred, &auth_str,
    557 			&auth_len, verf_str, verf_len)) {
    558 			error = nfs_getauth(nmp, rep, cred, &auth_str,
    559 				&auth_len, verf_str, &verf_len, key);
    560 			if (error) {
    561 				kmem_free(rep, sizeof(*rep));
    562 				m_freem(mrest);
    563 				KASSERT(kauth_cred_getrefcnt(acred) == 1);
    564 				kauth_cred_free(acred);
    565 				return (error);
    566 			}
    567 		}
    568 		retry_cred = false;
    569 	} else {
    570 		/* AUTH_UNIX */
    571 		uid_t uid;
    572 		gid_t gid;
    573 
    574 		/*
    575 		 * on the most unix filesystems, permission checks are
    576 		 * done when the file is open(2)'ed.
    577 		 * ie. once a file is successfully open'ed,
    578 		 * following i/o operations never fail with EACCES.
    579 		 * we try to follow the semantics as far as possible.
    580 		 *
    581 		 * note that we expect that the nfs server always grant
    582 		 * accesses by the file's owner.
    583 		 */
    584 		origcred = cred;
    585 		switch (procnum) {
    586 		case NFSPROC_READ:
    587 		case NFSPROC_WRITE:
    588 		case NFSPROC_COMMIT:
    589 			uid = np->n_vattr->va_uid;
    590 			gid = np->n_vattr->va_gid;
    591 			if (kauth_cred_geteuid(cred) == uid &&
    592 			    kauth_cred_getegid(cred) == gid) {
    593 				retry_cred = false;
    594 				break;
    595 			}
    596 			if (use_opencred)
    597 				break;
    598 			kauth_cred_setuid(acred, uid);
    599 			kauth_cred_seteuid(acred, uid);
    600 			kauth_cred_setsvuid(acred, uid);
    601 			kauth_cred_setgid(acred, gid);
    602 			kauth_cred_setegid(acred, gid);
    603 			kauth_cred_setsvgid(acred, gid);
    604 			cred = acred;
    605 			break;
    606 		default:
    607 			retry_cred = false;
    608 			break;
    609 		}
    610 		/*
    611 		 * backup mbuf chain if we can need it later to retry.
    612 		 *
    613 		 * XXX maybe we can keep a direct reference to
    614 		 * mrest without doing m_copym, but it's ...ugly.
    615 		 */
    616 		if (retry_cred)
    617 			mrest_backup = m_copym(mrest, 0, M_COPYALL, M_WAIT);
    618 		auth_type = RPCAUTH_UNIX;
    619 		/* XXX elad - ngroups */
    620 		auth_len = (((kauth_cred_ngroups(cred) > nmp->nm_numgrps) ?
    621 			nmp->nm_numgrps : kauth_cred_ngroups(cred)) << 2) +
    622 			5 * NFSX_UNSIGNED;
    623 	}
    624 	m = nfsm_rpchead(cred, nmp->nm_flag, procnum, auth_type, auth_len,
    625 	     auth_str, verf_len, verf_str, mrest, mrest_len, &mheadend, &xid);
    626 	if (auth_str)
    627 		free(auth_str, M_TEMP);
    628 
    629 	/*
    630 	 * For stream protocols, insert a Sun RPC Record Mark.
    631 	 */
    632 	if (nmp->nm_sotype == SOCK_STREAM) {
    633 		M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
    634 		*mtod(m, u_int32_t *) = htonl(0x80000000 |
    635 			 (m->m_pkthdr.len - NFSX_UNSIGNED));
    636 	}
    637 	rep->r_mreq = m;
    638 	rep->r_xid = xid;
    639 tryagain:
    640 	if (nmp->nm_flag & NFSMNT_SOFT)
    641 		rep->r_retry = nmp->nm_retry;
    642 	else
    643 		rep->r_retry = NFS_MAXREXMIT + 1;	/* past clip limit */
    644 	rep->r_rtt = rep->r_rexmit = 0;
    645 	if (nfs_proct[procnum] > 0)
    646 		rep->r_flags = R_TIMING;
    647 	else
    648 		rep->r_flags = 0;
    649 	rep->r_mrep = NULL;
    650 
    651 	/*
    652 	 * Do the client side RPC.
    653 	 */
    654 	nfsstats.rpcrequests++;
    655 	/*
    656 	 * Chain request into list of outstanding requests. Be sure
    657 	 * to put it LAST so timer finds oldest requests first.
    658 	 */
    659 	s = splsoftnet();
    660 	mutex_enter(&nfs_reqq_lock);
    661 	TAILQ_INSERT_TAIL(&nfs_reqq, rep, r_chain);
    662 	mutex_exit(&nfs_reqq_lock);
    663 	nfs_timer_start();
    664 
    665 	/*
    666 	 * If backing off another request or avoiding congestion, don't
    667 	 * send this one now but let timer do it. If not timing a request,
    668 	 * do it now.
    669 	 */
    670 	if (nmp->nm_so && (nmp->nm_sotype != SOCK_DGRAM ||
    671 	    (nmp->nm_flag & NFSMNT_DUMBTIMR) || nmp->nm_sent < nmp->nm_cwnd)) {
    672 		splx(s);
    673 		if (nmp->nm_soflags & PR_CONNREQUIRED)
    674 			error = nfs_sndlock(nmp, rep);
    675 		if (!error) {
    676 			m = m_copym(rep->r_mreq, 0, M_COPYALL, M_WAIT);
    677 			error = nfs_send(nmp->nm_so, nmp->nm_nam, m, rep, lwp);
    678 			if (nmp->nm_soflags & PR_CONNREQUIRED)
    679 				nfs_sndunlock(nmp);
    680 		}
    681 		s = splsoftnet();
    682 		if (!error && (rep->r_flags & R_MUSTRESEND) == 0) {
    683 			if ((rep->r_flags & R_SENT) == 0) {
    684 				nmp->nm_sent += NFS_CWNDSCALE;
    685 				rep->r_flags |= R_SENT;
    686 			}
    687 		}
    688 		splx(s);
    689 	} else {
    690 		splx(s);
    691 		rep->r_rtt = -1;
    692 	}
    693 
    694 	/*
    695 	 * Wait for the reply from our send or the timer's.
    696 	 */
    697 	if (!error || error == EPIPE || error == EWOULDBLOCK)
    698 		error = nfs_reply(rep, lwp);
    699 
    700 	/*
    701 	 * RPC done, unlink the request.
    702 	 */
    703 	s = splsoftnet();
    704 	mutex_enter(&nfs_reqq_lock);
    705 	TAILQ_REMOVE(&nfs_reqq, rep, r_chain);
    706 	mutex_exit(&nfs_reqq_lock);
    707 
    708 	/*
    709 	 * Decrement the outstanding request count.
    710 	 */
    711 	if (rep->r_flags & R_SENT) {
    712 		rep->r_flags &= ~R_SENT;	/* paranoia */
    713 		nmp->nm_sent -= NFS_CWNDSCALE;
    714 	}
    715 	splx(s);
    716 
    717 	if (rexmitp != NULL) {
    718 		int rexmit;
    719 
    720 		if (nmp->nm_sotype != SOCK_DGRAM)
    721 			rexmit = (rep->r_flags & R_REXMITTED) != 0;
    722 		else
    723 			rexmit = rep->r_rexmit;
    724 		*rexmitp = rexmit;
    725 	}
    726 
    727 	/*
    728 	 * If there was a successful reply and a tprintf msg.
    729 	 * tprintf a response.
    730 	 */
    731 	if (!error && (rep->r_flags & R_TPRINTFMSG))
    732 		nfs_msg(rep->r_lwp, nmp->nm_mountp->mnt_stat.f_mntfromname,
    733 		    "is alive again");
    734 	mrep = rep->r_mrep;
    735 	md = rep->r_md;
    736 	dpos = rep->r_dpos;
    737 	if (error)
    738 		goto nfsmout;
    739 
    740 	/*
    741 	 * break down the rpc header and check if ok
    742 	 */
    743 	nfsm_dissect(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
    744 	if (*tl++ == rpc_msgdenied) {
    745 		if (*tl == rpc_mismatch)
    746 			error = EOPNOTSUPP;
    747 		else if ((nmp->nm_flag & NFSMNT_KERB) && *tl++ == rpc_autherr) {
    748 			if (!failed_auth) {
    749 				failed_auth++;
    750 				mheadend->m_next = NULL;
    751 				m_freem(mrep);
    752 				m_freem(rep->r_mreq);
    753 				goto kerbauth;
    754 			} else
    755 				error = EAUTH;
    756 		} else
    757 			error = EACCES;
    758 		m_freem(mrep);
    759 		goto nfsmout;
    760 	}
    761 
    762 	/*
    763 	 * Grab any Kerberos verifier, otherwise just throw it away.
    764 	 */
    765 	verf_type = fxdr_unsigned(int, *tl++);
    766 	i = fxdr_unsigned(int32_t, *tl);
    767 	if ((nmp->nm_flag & NFSMNT_KERB) && verf_type == RPCAUTH_KERB4) {
    768 		error = nfs_savenickauth(nmp, cred, i, key, &md, &dpos, mrep);
    769 		if (error)
    770 			goto nfsmout;
    771 	} else if (i > 0)
    772 		nfsm_adv(nfsm_rndup(i));
    773 	nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
    774 	/* 0 == ok */
    775 	if (*tl == 0) {
    776 		nfsm_dissect(tl, u_int32_t *, NFSX_UNSIGNED);
    777 		if (*tl != 0) {
    778 			error = fxdr_unsigned(int, *tl);
    779 			switch (error) {
    780 			case NFSERR_PERM:
    781 				error = EPERM;
    782 				break;
    783 
    784 			case NFSERR_NOENT:
    785 				error = ENOENT;
    786 				break;
    787 
    788 			case NFSERR_IO:
    789 				error = EIO;
    790 				break;
    791 
    792 			case NFSERR_NXIO:
    793 				error = ENXIO;
    794 				break;
    795 
    796 			case NFSERR_ACCES:
    797 				error = EACCES;
    798 				if (!retry_cred)
    799 					break;
    800 				m_freem(mrep);
    801 				m_freem(rep->r_mreq);
    802 				kmem_free(rep, sizeof(*rep));
    803 				use_opencred = !use_opencred;
    804 				if (mrest_backup == NULL) {
    805 					/* m_copym failure */
    806 					KASSERT(
    807 					    kauth_cred_getrefcnt(acred) == 1);
    808 					kauth_cred_free(acred);
    809 					return ENOMEM;
    810 				}
    811 				mrest = mrest_backup;
    812 				mrest_backup = NULL;
    813 				cred = origcred;
    814 				error = 0;
    815 				retry_cred = false;
    816 				goto tryagain_cred;
    817 
    818 			case NFSERR_EXIST:
    819 				error = EEXIST;
    820 				break;
    821 
    822 			case NFSERR_XDEV:
    823 				error = EXDEV;
    824 				break;
    825 
    826 			case NFSERR_NODEV:
    827 				error = ENODEV;
    828 				break;
    829 
    830 			case NFSERR_NOTDIR:
    831 				error = ENOTDIR;
    832 				break;
    833 
    834 			case NFSERR_ISDIR:
    835 				error = EISDIR;
    836 				break;
    837 
    838 			case NFSERR_INVAL:
    839 				error = EINVAL;
    840 				break;
    841 
    842 			case NFSERR_FBIG:
    843 				error = EFBIG;
    844 				break;
    845 
    846 			case NFSERR_NOSPC:
    847 				error = ENOSPC;
    848 				break;
    849 
    850 			case NFSERR_ROFS:
    851 				error = EROFS;
    852 				break;
    853 
    854 			case NFSERR_MLINK:
    855 				error = EMLINK;
    856 				break;
    857 
    858 			case NFSERR_TIMEDOUT:
    859 				error = ETIMEDOUT;
    860 				break;
    861 
    862 			case NFSERR_NAMETOL:
    863 				error = ENAMETOOLONG;
    864 				break;
    865 
    866 			case NFSERR_NOTEMPTY:
    867 				error = ENOTEMPTY;
    868 				break;
    869 
    870 			case NFSERR_DQUOT:
    871 				error = EDQUOT;
    872 				break;
    873 
    874 			case NFSERR_STALE:
    875 				/*
    876 				 * If the File Handle was stale, invalidate the
    877 				 * lookup cache, just in case.
    878 				 */
    879 				error = ESTALE;
    880 				cache_purge(NFSTOV(np));
    881 				break;
    882 
    883 			case NFSERR_REMOTE:
    884 				error = EREMOTE;
    885 				break;
    886 
    887 			case NFSERR_WFLUSH:
    888 			case NFSERR_BADHANDLE:
    889 			case NFSERR_NOT_SYNC:
    890 			case NFSERR_BAD_COOKIE:
    891 				error = EINVAL;
    892 				break;
    893 
    894 			case NFSERR_NOTSUPP:
    895 				error = ENOTSUP;
    896 				break;
    897 
    898 			case NFSERR_TOOSMALL:
    899 			case NFSERR_SERVERFAULT:
    900 			case NFSERR_BADTYPE:
    901 				error = EINVAL;
    902 				break;
    903 
    904 			case NFSERR_TRYLATER:
    905 				if ((nmp->nm_flag & NFSMNT_NFSV3) == 0)
    906 					break;
    907 				m_freem(mrep);
    908 				error = 0;
    909 				waituntil = time_second + trylater_delay;
    910 				while (time_second < waituntil) {
    911 					kpause("nfstrylater", false, hz, NULL);
    912 				}
    913 				trylater_delay *= NFS_TRYLATERDELMUL;
    914 				if (trylater_delay > NFS_TRYLATERDELMAX)
    915 					trylater_delay = NFS_TRYLATERDELMAX;
    916 				/*
    917 				 * RFC1813:
    918 				 * The client should wait and then try
    919 				 * the request with a new RPC transaction ID.
    920 				 */
    921 				nfs_renewxid(rep);
    922 				goto tryagain;
    923 
    924 			default:
    925 #ifdef DIAGNOSTIC
    926 				printf("Invalid rpc error code %d\n", error);
    927 #endif
    928 				error = EINVAL;
    929 				break;
    930 			}
    931 
    932 			if (nmp->nm_flag & NFSMNT_NFSV3) {
    933 				*mrp = mrep;
    934 				*mdp = md;
    935 				*dposp = dpos;
    936 				error |= NFSERR_RETERR;
    937 			} else
    938 				m_freem(mrep);
    939 			goto nfsmout;
    940 		}
    941 
    942 		/*
    943 		 * note which credential worked to minimize number of retries.
    944 		 */
    945 		if (use_opencred)
    946 			np->n_flag |= NUSEOPENCRED;
    947 		else
    948 			np->n_flag &= ~NUSEOPENCRED;
    949 
    950 		*mrp = mrep;
    951 		*mdp = md;
    952 		*dposp = dpos;
    953 
    954 		KASSERT(error == 0);
    955 		goto nfsmout;
    956 	}
    957 	m_freem(mrep);
    958 	error = EPROTONOSUPPORT;
    959 nfsmout:
    960 	KASSERT(kauth_cred_getrefcnt(acred) == 1);
    961 	kauth_cred_free(acred);
    962 	m_freem(rep->r_mreq);
    963 	kmem_free(rep, sizeof(*rep));
    964 	m_freem(mrest_backup);
    965 	return (error);
    966 }
    967 
    968 /*
    969  * Lock a socket against others.
    970  * Necessary for STREAM sockets to ensure you get an entire rpc request/reply
    971  * and also to avoid race conditions between the processes with nfs requests
    972  * in progress when a reconnect is necessary.
    973  */
    974 static int
    975 nfs_sndlock(struct nfsmount *nmp, struct nfsreq *rep)
    976 {
    977 	struct lwp *l;
    978 	int timeo = 0;
    979 	bool catch_p = false;
    980 	int error = 0;
    981 
    982 	if (nmp->nm_flag & NFSMNT_SOFT)
    983 		timeo = nmp->nm_retry * nmp->nm_timeo;
    984 
    985 	if (nmp->nm_iflag & NFSMNT_DISMNTFORCE)
    986 		timeo = hz;
    987 
    988 	if (rep) {
    989 		l = rep->r_lwp;
    990 		if (rep->r_nmp->nm_flag & NFSMNT_INT)
    991 			catch_p = true;
    992 	} else
    993 		l = NULL;
    994 	mutex_enter(&nmp->nm_lock);
    995 	while ((nmp->nm_iflag & NFSMNT_SNDLOCK) != 0) {
    996 		if (rep && nfs_sigintr(rep->r_nmp, rep, l)) {
    997 			error = EINTR;
    998 			goto quit;
    999 		}
   1000 		if (catch_p) {
   1001 			error = cv_timedwait_sig(&nmp->nm_sndcv,
   1002 						 &nmp->nm_lock, timeo);
   1003 		} else {
   1004 			error = cv_timedwait(&nmp->nm_sndcv,
   1005 					     &nmp->nm_lock, timeo);
   1006 		}
   1007 
   1008 		if (error) {
   1009 			if ((error == EWOULDBLOCK) &&
   1010 			    (nmp->nm_flag & NFSMNT_SOFT)) {
   1011 				error = EIO;
   1012 				goto quit;
   1013 			}
   1014 			error = 0;
   1015 		}
   1016 		if (catch_p) {
   1017 			catch_p = false;
   1018 			timeo = 2 * hz;
   1019 		}
   1020 	}
   1021 	nmp->nm_iflag |= NFSMNT_SNDLOCK;
   1022 quit:
   1023 	mutex_exit(&nmp->nm_lock);
   1024 	return error;
   1025 }
   1026 
   1027 /*
   1028  * Unlock the stream socket for others.
   1029  */
   1030 static void
   1031 nfs_sndunlock(struct nfsmount *nmp)
   1032 {
   1033 
   1034 	mutex_enter(&nmp->nm_lock);
   1035 	if ((nmp->nm_iflag & NFSMNT_SNDLOCK) == 0)
   1036 		panic("nfs sndunlock");
   1037 	nmp->nm_iflag &= ~NFSMNT_SNDLOCK;
   1038 	cv_signal(&nmp->nm_sndcv);
   1039 	mutex_exit(&nmp->nm_lock);
   1040 }
   1041