/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1991, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Rick Macklem at The University of Guelph.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#include <sys/cdefs.h>
/*
 * Socket operations for use by nfs
 */

#include "opt_kgssapi.h"
#include "opt_nfs.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/vnode.h>

#include <rpc/rpc.h>
#include <rpc/krpc.h>

#include <kgssapi/krb5/kcrypto.h>

#include <fs/nfs/nfsport.h>

#ifdef KDTRACE_HOOKS
#include <sys/dtrace_bsd.h>

dtrace_nfsclient_nfs23_start_probe_func_t
                dtrace_nfscl_nfs234_start_probe;

dtrace_nfsclient_nfs23_done_probe_func_t
                dtrace_nfscl_nfs234_done_probe;

/*
 * Registered probes by RPC type.
 */
uint32_t        nfscl_nfs2_start_probes[NFSV41_NPROCS + 1];
uint32_t        nfscl_nfs2_done_probes[NFSV41_NPROCS + 1];

uint32_t        nfscl_nfs3_start_probes[NFSV41_NPROCS + 1];
uint32_t        nfscl_nfs3_done_probes[NFSV41_NPROCS + 1];

uint32_t        nfscl_nfs4_start_probes[NFSV41_NPROCS + 1];
uint32_t        nfscl_nfs4_done_probes[NFSV41_NPROCS + 1];
#endif

NFSSTATESPINLOCK;
NFSREQSPINLOCK;
NFSDLOCKMUTEX;
NFSCLSTATEMUTEX;
extern struct nfsstatsv1 nfsstatsv1;
extern struct nfsreqhead nfsd_reqq;
extern int nfscl_ticks;
extern void (*ncl_call_invalcaches)(struct vnode *);
extern int nfs_numnfscbd;
extern int nfscl_debuglevel;
extern int nfsrv_lease;

SVCPOOL         *nfscbd_pool;
int             nfs_bufpackets = 4;
static int      nfsrv_gsscallbackson = 0;
static int      nfs_reconnects;
static int      nfs3_jukebox_delay = 10;
static int      nfs_skip_wcc_data_onerr = 1;
static int      nfs_dsretries = 2;
static struct timespec  nfs_trylater_max = {
        .tv_sec         = NFS_TRYLATERDEL,
        .tv_nsec        = 0,
};

SYSCTL_DECL(_vfs_nfs);

SYSCTL_INT(_vfs_nfs, OID_AUTO, bufpackets, CTLFLAG_RW, &nfs_bufpackets, 0,
    "Buffer reservation size 2 < x < 64");
SYSCTL_INT(_vfs_nfs, OID_AUTO, reconnects, CTLFLAG_RD, &nfs_reconnects, 0,
    "Number of times the nfs client has had to reconnect");
SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs3_jukebox_delay, CTLFLAG_RW, &nfs3_jukebox_delay, 0,
    "Number of seconds to delay a retry after receiving EJUKEBOX");
SYSCTL_INT(_vfs_nfs, OID_AUTO, skip_wcc_data_onerr, CTLFLAG_RW, &nfs_skip_wcc_data_onerr, 0,
    "Disable weak cache consistency checking when server returns an error");
SYSCTL_INT(_vfs_nfs, OID_AUTO, dsretries, CTLFLAG_RW, &nfs_dsretries, 0,
    "Number of retries for a DS RPC before failure");

static void     nfs_down(struct nfsmount *, struct thread *, const char *,
    int, int);
static void     nfs_up(struct nfsmount *, struct thread *, const char *,
    int, int);
static int      nfs_msg(struct thread *, const char *, const char *, int);

struct nfs_cached_auth {
        int             ca_refs; /* refcount, including 1 from the cache */
        uid_t           ca_uid;  /* uid that corresponds to this auth */
        AUTH            *ca_auth; /* RPC auth handle */
};

static int nfsv2_procid[NFS_V3NPROCS] = {
        NFSV2PROC_NULL,
        NFSV2PROC_GETATTR,
        NFSV2PROC_SETATTR,
        NFSV2PROC_LOOKUP,
        NFSV2PROC_NOOP,
        NFSV2PROC_READLINK,
        NFSV2PROC_READ,
        NFSV2PROC_WRITE,
        NFSV2PROC_CREATE,
        NFSV2PROC_MKDIR,
        NFSV2PROC_SYMLINK,
        NFSV2PROC_CREATE,
        NFSV2PROC_REMOVE,
        NFSV2PROC_RMDIR,
        NFSV2PROC_RENAME,
        NFSV2PROC_LINK,
        NFSV2PROC_READDIR,
        NFSV2PROC_NOOP,
        NFSV2PROC_STATFS,
        NFSV2PROC_NOOP,
        NFSV2PROC_NOOP,
        NFSV2PROC_NOOP,
};

/*
 * This static array indicates that a NFSv4 RPC should use
 * RPCSEC_GSS, if the mount indicates that via sec=krb5[ip].
 * System RPCs that do not use file handles will be false
 * in this array so that they will use AUTH_SYS when the
 * "syskrb5" mount option is specified, along with
 * "sec=krb5[ip]".
 */
static bool nfscl_use_gss[NFSV42_NPROCS] = {
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        false,          /* SetClientID */
        false,          /* SetClientIDConfirm */
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        false,          /* Renew */
        true,
        false,          /* ReleaseLockOwn */
        true,
        true,
        true,
        true,
        true,
        true,
        false,          /* ExchangeID */
        false,          /* CreateSession */
        false,          /* DestroySession */
        false,          /* DestroyClientID */
        false,          /* FreeStateID */
        true,
        true,
        true,
        true,
        false,          /* ReclaimComplete */
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        true,
        false,          /* BindConnectionToSession */
        true,
        true,
        true,
        true,
        true,
};

/*
 * Initialize sockets and congestion for a new NFS connection.
 * We do not free the sockaddr if error.
 * Which arguments are set to NULL indicate what kind of call it is.
 * cred == NULL --> a call to connect to a pNFS DS
 * nmp == NULL --> indicates an upcall to userland or a NFSv4.0 callback
 */
int
newnfs_connect(struct nfsmount *nmp, struct nfssockreq *nrp,
    struct ucred *cred, NFSPROC_T *p, int callback_retry_mult, bool dotls,
    struct __rpc_client **clipp)
{
        int rcvreserve, sndreserve;
        int pktscale, pktscalesav;
        struct sockaddr *saddr;
        struct ucred *origcred;
        CLIENT *client;
        struct netconfig *nconf;
        struct socket *so;
        int one = 1, retries, error = 0;
        struct thread *td = curthread;
        SVCXPRT *xprt;
        struct timeval timo;
        uint64_t tval;

        /*
         * We need to establish the socket using the credentials of
         * the mountpoint.  Some parts of this process (such as
         * sobind() and soconnect()) will use the curent thread's
         * credential instead of the socket credential.  To work
         * around this, temporarily change the current thread's
         * credential to that of the mountpoint.
         *
         * XXX: It would be better to explicitly pass the correct
         * credential to sobind() and soconnect().
         */
        origcred = td->td_ucred;

        /*
         * Use the credential in nr_cred, if not NULL.
         */
        if (nrp->nr_cred != NULL)
                td->td_ucred = nrp->nr_cred;
        else
                td->td_ucred = cred;
        saddr = nrp->nr_nam;

        if (saddr->sa_family == AF_INET)
                if (nrp->nr_sotype == SOCK_DGRAM)
                        nconf = getnetconfigent("udp");
                else
                        nconf = getnetconfigent("tcp");
        else
                if (nrp->nr_sotype == SOCK_DGRAM)
                        nconf = getnetconfigent("udp6");
                else
                        nconf = getnetconfigent("tcp6");
                        
        pktscale = nfs_bufpackets;
        if (pktscale < 2)
                pktscale = 2;
        if (pktscale > 64)
                pktscale = 64;
        pktscalesav = pktscale;
        /*
         * soreserve() can fail if sb_max is too small, so shrink pktscale
         * and try again if there is an error.
         * Print a log message suggesting increasing sb_max.
         * Creating a socket and doing this is necessary since, if the
         * reservation sizes are too large and will make soreserve() fail,
         * the connection will work until a large send is attempted and
         * then it will loop in the krpc code.
         */
        so = NULL;
        saddr = NFSSOCKADDR(nrp->nr_nam, struct sockaddr *);
        error = socreate(saddr->sa_family, &so, nrp->nr_sotype, 
            nrp->nr_soproto, td->td_ucred, td);
        if (error != 0)
                goto out;
        do {
            if (error != 0 && pktscale > 2) {
                if (nmp != NULL && nrp->nr_sotype == SOCK_STREAM &&
                    pktscale == pktscalesav) {
                    /*
                     * Suggest vfs.nfs.bufpackets * maximum RPC message,
                     * adjusted for the sb_max->sb_max_adj conversion of
                     * MCLBYTES / (MSIZE + MCLBYTES) as the minimum setting
                     * for kern.ipc.maxsockbuf.
                     */
                    tval = (NFS_MAXBSIZE + NFS_MAXXDR) * nfs_bufpackets;
                    tval *= MSIZE + MCLBYTES;
                    tval += MCLBYTES - 1; /* Round up divide by MCLBYTES. */
                    tval /= MCLBYTES;
                    printf("Consider increasing kern.ipc.maxsockbuf to a "
                        "minimum of %ju to support %ubyte NFS I/O\n",
                        (uintmax_t)tval, NFS_MAXBSIZE);
                }
                pktscale--;
            }
            if (nrp->nr_sotype == SOCK_DGRAM) {
                if (nmp != NULL) {
                        sndreserve = (NFS_MAXDGRAMDATA + NFS_MAXPKTHDR) *
                            pktscale;
                        rcvreserve = (NFS_MAXDGRAMDATA + NFS_MAXPKTHDR) *
                            pktscale;
                } else {
                        sndreserve = rcvreserve = 1024 * pktscale;
                }
            } else {
                if (nrp->nr_sotype != SOCK_STREAM)
                        panic("nfscon sotype");
                if (nmp != NULL) {
                        sndreserve = (NFS_MAXBSIZE + NFS_MAXXDR) *
                            pktscale;
                        rcvreserve = (NFS_MAXBSIZE + NFS_MAXXDR) *
                            pktscale;
                } else {
                        sndreserve = rcvreserve = 1024 * pktscale;
                }
            }
            error = soreserve(so, sndreserve, rcvreserve);
            if (error != 0 && nmp != NULL && nrp->nr_sotype == SOCK_STREAM &&
                pktscale <= 2)
                printf("Must increase kern.ipc.maxsockbuf or reduce"
                    " rsize, wsize\n");
        } while (error != 0 && pktscale > 2);
        soclose(so);
        if (error != 0)
                goto out;

        client = clnt_reconnect_create(nconf, saddr, nrp->nr_prog,
            nrp->nr_vers, sndreserve, rcvreserve);
        CLNT_CONTROL(client, CLSET_WAITCHAN, "nfsreq");
        if (nmp != NULL) {
                if ((nmp->nm_flag & NFSMNT_INT))
                        CLNT_CONTROL(client, CLSET_INTERRUPTIBLE, &one);
                if ((nmp->nm_flag & NFSMNT_RESVPORT))
                        CLNT_CONTROL(client, CLSET_PRIVPORT, &one);
                if (NFSHASTLS(nmp)) {
                        CLNT_CONTROL(client, CLSET_TLS, &one);
                        if (nmp->nm_tlscertname != NULL)
                                CLNT_CONTROL(client, CLSET_TLSCERTNAME,
                                    nmp->nm_tlscertname);
                }
                if (NFSHASSOFT(nmp)) {
                        if (nmp->nm_sotype == SOCK_DGRAM)
                                /*
                                 * For UDP, the large timeout for a reconnect
                                 * will be set to "nm_retry * nm_timeo / 2", so
                                 * we only want to do 2 reconnect timeout
                                 * retries.
                                 */
                                retries = 2;
                        else
                                retries = nmp->nm_retry;
                } else
                        retries = INT_MAX;
                if (NFSHASNFSV4N(nmp)) {
                        if (cred != NULL) {
                                if (NFSHASSOFT(nmp)) {
                                        /*
                                         * This should be a DS mount.
                                         * Use CLSET_TIMEOUT to set the timeout
                                         * for connections to DSs instead of
                                         * specifying a timeout on each RPC.
                                         * This is done so that SO_SNDTIMEO
                                         * is set on the TCP socket as well
                                         * as specifying a time limit when
                                         * waiting for an RPC reply.  Useful
                                         * if the send queue for the TCP
                                         * connection has become constipated,
                                         * due to a failed DS.
                                         * The choice of lease_duration / 4 is
                                         * fairly arbitrary, but seems to work
                                         * ok, with a lower bound of 10sec.
                                         */
                                        timo.tv_sec = nfsrv_lease / 4;
                                        if (timo.tv_sec < 10)
                                                timo.tv_sec = 10;
                                        timo.tv_usec = 0;
                                        CLNT_CONTROL(client, CLSET_TIMEOUT,
                                            &timo);
                                }
                                /*
                                 * Make sure the nfscbd_pool doesn't get
                                 * destroyed while doing this.
                                 */
                                NFSD_LOCK();
                                if (nfs_numnfscbd > 0) {
                                        nfs_numnfscbd++;
                                        NFSD_UNLOCK();
                                        xprt = svc_vc_create_backchannel(
                                            nfscbd_pool);
                                        CLNT_CONTROL(client, CLSET_BACKCHANNEL,
                                            xprt);
                                        NFSD_LOCK();
                                        nfs_numnfscbd--;
                                        if (nfs_numnfscbd == 0)
                                                wakeup(&nfs_numnfscbd);
                                }
                                NFSD_UNLOCK();
                        } else {
                                /*
                                 * cred == NULL for a DS connect.
                                 * For connects to a DS, set a retry limit
                                 * so that failed DSs will be detected.
                                 * This is ok for NFSv4.1, since a DS does
                                 * not maintain open/lock state and is the
                                 * only case where using a "soft" mount is
                                 * recommended for NFSv4.
                                 * For mounts from the MDS to DS, this is done
                                 * via mount options, but that is not the case
                                 * here.  The retry limit here can be adjusted
                                 * via the sysctl vfs.nfs.dsretries.
                                 * See the comment above w.r.t. timeout.
                                 */
                                timo.tv_sec = nfsrv_lease / 4;
                                if (timo.tv_sec < 10)
                                        timo.tv_sec = 10;
                                timo.tv_usec = 0;
                                CLNT_CONTROL(client, CLSET_TIMEOUT, &timo);
                                retries = nfs_dsretries;
                        }
                }
        } else {
                /*
                 * Three cases:
                 * - Null RPC callback to client
                 * - Non-Null RPC callback to client, wait a little longer
                 * - upcalls to nfsuserd and gssd (clp == NULL)
                 */
                if (callback_retry_mult == 0) {
                        retries = NFSV4_UPCALLRETRY;
                        CLNT_CONTROL(client, CLSET_PRIVPORT, &one);
                } else {
                        retries = NFSV4_CALLBACKRETRY * callback_retry_mult;
                }
                if (dotls)
                        CLNT_CONTROL(client, CLSET_TLS, &one);
        }
        CLNT_CONTROL(client, CLSET_RETRIES, &retries);

        if (nmp != NULL) {
                /*
                 * For UDP, there are 2 timeouts:
                 * - CLSET_RETRY_TIMEOUT sets the initial timeout for the timer
                 *   that does a retransmit of an RPC request using the same 
                 *   socket and xid. This is what you normally want to do,
                 *   since NFS servers depend on "same xid" for their
                 *   Duplicate Request Cache.
                 * - timeout specified in CLNT_CALL_MBUF(), which specifies when
                 *   retransmits on the same socket should fail and a fresh
                 *   socket created. Each of these timeouts counts as one
                 *   CLSET_RETRIES as set above.
                 * Set the initial retransmit timeout for UDP. This timeout
                 * doesn't exist for TCP and the following call just fails,
                 * which is ok.
                 */
                timo.tv_sec = nmp->nm_timeo / NFS_HZ;
                timo.tv_usec = (nmp->nm_timeo % NFS_HZ) * 1000000 / NFS_HZ;
                CLNT_CONTROL(client, CLSET_RETRY_TIMEOUT, &timo);
        }

        /*
         * *clipp is &nrp->nr_client or &nm_aconn[nmp->nm_nextaconn].
         * The latter case is for additional connections specified by the
         * "nconnect" mount option.  nr_mtx etc is used for these additional
         * connections, as well as nr_client in the nfssockreq
         * structure for the mount.
         */
        mtx_lock(&nrp->nr_mtx);
        if (*clipp != NULL) {
                mtx_unlock(&nrp->nr_mtx);
                /*
                 * Someone else already connected.
                 */
                CLNT_RELEASE(client);
        } else {
                *clipp = client;
                /*
                 * Protocols that do not require connections may be optionally
                 * left unconnected for servers that reply from a port other
                 * than NFS_PORT.
                 */
                if (nmp == NULL || (nmp->nm_flag & NFSMNT_NOCONN) == 0) {
                        mtx_unlock(&nrp->nr_mtx);
                        CLNT_CONTROL(client, CLSET_CONNECT, &one);
                } else
                        mtx_unlock(&nrp->nr_mtx);
        }

out:
        /* Restore current thread's credentials. */
        td->td_ucred = origcred;

        NFSEXITCODE(error);
        return (error);
}

/*
 * NFS disconnect. Clean up and unlink.
 */
void
newnfs_disconnect(struct nfsmount *nmp, struct nfssockreq *nrp)
{
        CLIENT *client, *aconn[NFS_MAXNCONN - 1];
        int i;

        mtx_lock(&nrp->nr_mtx);
        if (nrp->nr_client != NULL) {
                client = nrp->nr_client;
                nrp->nr_client = NULL;
                if (nmp != NULL && nmp->nm_aconnect > 0) {
                        for (i = 0; i < nmp->nm_aconnect; i++) {
                                aconn[i] = nmp->nm_aconn[i];
                                nmp->nm_aconn[i] = NULL;
                        }
                }
                mtx_unlock(&nrp->nr_mtx);
                rpc_gss_secpurge_call(client);
                CLNT_CLOSE(client);
                CLNT_RELEASE(client);
                if (nmp != NULL && nmp->nm_aconnect > 0) {
                        for (i = 0; i < nmp->nm_aconnect; i++) {
                                if (aconn[i] != NULL) {
                                        rpc_gss_secpurge_call(aconn[i]);
                                        CLNT_CLOSE(aconn[i]);
                                        CLNT_RELEASE(aconn[i]);
                                }
                        }
                }
        } else {
                mtx_unlock(&nrp->nr_mtx);
        }
}

static AUTH *
nfs_getauth(struct nfssockreq *nrp, int secflavour, char *clnt_principal,
    char *srv_principal, gss_OID mech_oid, struct ucred *cred)
{
        rpc_gss_service_t svc;
        AUTH *auth;

        switch (secflavour) {
        case RPCSEC_GSS_KRB5:
        case RPCSEC_GSS_KRB5I:
        case RPCSEC_GSS_KRB5P:
                if (!mech_oid) {
                        if (!rpc_gss_mech_to_oid_call("kerberosv5", &mech_oid))
                                return (NULL);
                }
                if (secflavour == RPCSEC_GSS_KRB5)
                        svc = rpc_gss_svc_none;
                else if (secflavour == RPCSEC_GSS_KRB5I)
                        svc = rpc_gss_svc_integrity;
                else
                        svc = rpc_gss_svc_privacy;

                if (clnt_principal == NULL) {
                        NFSCL_DEBUG(1, "nfs_getauth: clnt princ=NULL, "
                            "srv princ=%s\n", srv_principal);
                        auth = rpc_gss_secfind_call(nrp->nr_client, cred,
                            srv_principal, mech_oid, svc);
                } else {
                        NFSCL_DEBUG(1, "nfs_getauth: clnt princ=%s "
                            "srv princ=%s\n", clnt_principal, srv_principal);
                        auth = rpc_gss_seccreate_call(nrp->nr_client, cred,
                            clnt_principal, srv_principal, "kerberosv5",
                            svc, NULL, NULL, NULL);
                        return (auth);
                }
                if (auth != NULL)
                        return (auth);
                /* fallthrough */
        case AUTH_SYS:
        default:
                return (authunix_create(cred));
        }
}

/*
 * Callback from the RPC code to generate up/down notifications.
 */

struct nfs_feedback_arg {
        struct nfsmount *nf_mount;
        int             nf_lastmsg;     /* last tprintf */
        int             nf_tprintfmsg;
        struct thread   *nf_td;
};

static void
nfs_feedback(int type, int proc, void *arg)
{
        struct nfs_feedback_arg *nf = (struct nfs_feedback_arg *) arg;
        struct nfsmount *nmp = nf->nf_mount;
        time_t now;

        switch (type) {
        case FEEDBACK_REXMIT2:
        case FEEDBACK_RECONNECT:
                now = NFSD_MONOSEC;
                if (nf->nf_lastmsg + nmp->nm_tprintf_delay < now) {
                        nfs_down(nmp, nf->nf_td,
                            "not responding", 0, NFSSTA_TIMEO);
                        nf->nf_tprintfmsg = TRUE;
                        nf->nf_lastmsg = now;
                }
                break;

        case FEEDBACK_OK:
                nfs_up(nf->nf_mount, nf->nf_td,
                    "is alive again", NFSSTA_TIMEO, nf->nf_tprintfmsg);
                break;
        }
}

/*
 * newnfs_request - goes something like this
 *      - does the rpc by calling the krpc layer
 *      - break down rpc header and return with nfs reply
 * nb: always frees up nd_mreq mbuf list
 */
int
newnfs_request(struct nfsrv_descript *nd, struct nfsmount *nmp,
    struct nfsclient *clp, struct nfssockreq *nrp, vnode_t vp,
    struct thread *td, struct ucred *cred, u_int32_t prog, u_int32_t vers,
    u_char *retsum, int toplevel, u_int64_t *xidp, struct nfsclsession *dssep)
{
        uint32_t retseq, retval, retval0, slotseq, *tl;
        int i = 0, j = 0, opcnt, set_sigset = 0, slot;
        int error = 0, usegssname = 0, secflavour = AUTH_SYS;
        int freeslot, maxslot, reterr, slotpos, timeo;
        u_int16_t procnum;
        u_int nextconn;
        struct nfs_feedback_arg nf;
        struct timeval timo;
        AUTH *auth;
        struct rpc_callextra ext;
        enum clnt_stat stat;
        struct nfsreq *rep = NULL;
        char *srv_principal = NULL, *clnt_principal = NULL;
        sigset_t oldset;
        struct ucred *authcred;
        struct nfsclsession *sep;
        uint8_t sessionid[NFSX_V4SESSIONID];
        bool nextconn_set;
        struct timespec trylater_delay, ts, waituntil;

        /* Initially 1msec. */
        trylater_delay.tv_sec = 0;
        trylater_delay.tv_nsec = 1000000;
        sep = dssep;
        if (xidp != NULL)
                *xidp = 0;
        /* Reject requests while attempting a forced unmount. */
        if (nmp != NULL && NFSCL_FORCEDISM(nmp->nm_mountp)) {
                m_freem(nd->nd_mreq);
                return (ESTALE);
        }

        /*
         * Set authcred, which is used to acquire RPC credentials to
         * the cred argument, by default. The crhold() should not be
         * necessary, but will ensure that some future code change
         * doesn't result in the credential being free'd prematurely.
         */
        authcred = crhold(cred);

        /* For client side interruptible mounts, mask off the signals. */
        if (nmp != NULL && td != NULL && NFSHASINT(nmp)) {
                newnfs_set_sigmask(td, &oldset);
                set_sigset = 1;
        }

        /*
         * If not already connected call newnfs_connect now.
         */
        if (nrp->nr_client == NULL)
                newnfs_connect(nmp, nrp, cred, td, 0, false, &nrp->nr_client);

        /*
         * If the "nconnect" mount option was specified and this RPC is
         * one that can have a large RPC message and is being done through
         * the NFS/MDS server, use an additional connection. (When the RPC is
         * being done through the server/MDS, nrp == &nmp->nm_sockreq.)
         * The "nconnect" mount option normally has minimal effect when the
         * "pnfs" mount option is specified, since only Readdir RPCs are
         * normally done through the NFS/MDS server.
         */
        nextconn_set = false;
        if (nmp != NULL && nmp->nm_aconnect > 0 && nrp == &nmp->nm_sockreq &&
            (nd->nd_procnum == NFSPROC_READ ||
             nd->nd_procnum == NFSPROC_READDIR ||
             nd->nd_procnum == NFSPROC_READDIRPLUS ||
             nd->nd_procnum == NFSPROC_WRITE)) {
                nextconn = atomic_fetchadd_int(&nmp->nm_nextaconn, 1);
                nextconn %= nmp->nm_aconnect;
                nextconn_set = true;
                if (nmp->nm_aconn[nextconn] == NULL)
                        newnfs_connect(nmp, nrp, cred, td, 0, false,
                            &nmp->nm_aconn[nextconn]);
        }

        /*
         * For a client side mount, nmp is != NULL and clp == NULL. For
         * server calls (callbacks or upcalls), nmp == NULL.
         */
        if (clp != NULL) {
                NFSLOCKSTATE();
                if ((clp->lc_flags & LCL_GSS) && nfsrv_gsscallbackson) {
                        secflavour = RPCSEC_GSS_KRB5;
                        if (nd->nd_procnum != NFSPROC_NULL) {
                                if (clp->lc_flags & LCL_GSSINTEGRITY)
                                        secflavour = RPCSEC_GSS_KRB5I;
                                else if (clp->lc_flags & LCL_GSSPRIVACY)
                                        secflavour = RPCSEC_GSS_KRB5P;
                        }
                }
                NFSUNLOCKSTATE();
        } else if (nmp != NULL && NFSHASKERB(nmp) &&
             nd->nd_procnum != NFSPROC_NULL && (!NFSHASSYSKRB5(nmp) ||
             nfscl_use_gss[nd->nd_procnum])) {
                if (NFSHASALLGSSNAME(nmp) && nmp->nm_krbnamelen > 0)
                        nd->nd_flag |= ND_USEGSSNAME;
                if ((nd->nd_flag & ND_USEGSSNAME) != 0) {
                        /*
                         * If there is a client side host based credential,
                         * use that, otherwise use the system uid, if set.
                         * The system uid is in the nmp->nm_sockreq.nr_cred
                         * credentials.
                         */
                        if (nmp->nm_krbnamelen > 0) {
                                usegssname = 1;
                                clnt_principal = nmp->nm_krbname;
                        } else if (nmp->nm_uid != (uid_t)-1) {
                                KASSERT(nmp->nm_sockreq.nr_cred != NULL,
                                    ("newnfs_request: NULL nr_cred"));
                                crfree(authcred);
                                authcred = crhold(nmp->nm_sockreq.nr_cred);
                        }
                } else if (nmp->nm_krbnamelen == 0 &&
                    nmp->nm_uid != (uid_t)-1 && cred->cr_uid == (uid_t)0) {
                        /*
                         * If there is no host based principal name and
                         * the system uid is set and this is root, use the
                         * system uid, since root won't have user
                         * credentials in a credentials cache file.
                         * The system uid is in the nmp->nm_sockreq.nr_cred
                         * credentials.
                         */
                        KASSERT(nmp->nm_sockreq.nr_cred != NULL,
                            ("newnfs_request: NULL nr_cred"));
                        crfree(authcred);
                        authcred = crhold(nmp->nm_sockreq.nr_cred);
                }
                if (NFSHASINTEGRITY(nmp))
                        secflavour = RPCSEC_GSS_KRB5I;
                else if (NFSHASPRIVACY(nmp))
                        secflavour = RPCSEC_GSS_KRB5P;
                else
                        secflavour = RPCSEC_GSS_KRB5;
                if (nrp->nr_srvprinc[0] == '\0')
                        srv_principal = NFSMNT_SRVKRBNAME(nmp);
                else
                        srv_principal = nrp->nr_srvprinc;
        } else if (nmp != NULL && (!NFSHASKERB(nmp) || NFSHASSYSKRB5(nmp)) &&
            nd->nd_procnum != NFSPROC_NULL &&
            (nd->nd_flag & ND_USEGSSNAME) != 0) {
                /*
                 * Use the uid that did the mount when the RPC is doing
                 * NFSv4 system operations, as indicated by the
                 * ND_USEGSSNAME flag, for the AUTH_SYS case.
                 * The credentials in nm_sockreq.nr_cred were used for the
                 * mount.
                 */
                KASSERT(nmp->nm_sockreq.nr_cred != NULL,
                    ("newnfs_request: NULL nr_cred"));
                crfree(authcred);
                authcred = crhold(nmp->nm_sockreq.nr_cred);
        }

        if (nmp != NULL) {
                bzero(&nf, sizeof(struct nfs_feedback_arg));
                nf.nf_mount = nmp;
                nf.nf_td = td;
                nf.nf_lastmsg = NFSD_MONOSEC -
                    ((nmp->nm_tprintf_delay)-(nmp->nm_tprintf_initial_delay));
        }

        if (nd->nd_procnum == NFSPROC_NULL)
                auth = authnone_create();
        else if (usegssname) {
                /*
                 * For this case, the authenticator is held in the
                 * nfssockreq structure, so don't release the reference count
                 * held on it. --> Don't AUTH_DESTROY() it in this function.
                 */
                if (nrp->nr_auth == NULL)
                        nrp->nr_auth = nfs_getauth(nrp, secflavour,
                            clnt_principal, srv_principal, NULL, authcred);
                else
                        rpc_gss_refresh_auth_call(nrp->nr_auth);
                auth = nrp->nr_auth;
        } else
                auth = nfs_getauth(nrp, secflavour, NULL,
                    srv_principal, NULL, authcred);
        crfree(authcred);
        if (auth == NULL) {
                m_freem(nd->nd_mreq);
                if (set_sigset)
                        newnfs_restore_sigmask(td, &oldset);
                return (EACCES);
        }
        bzero(&ext, sizeof(ext));
        ext.rc_auth = auth;
        if (nmp != NULL) {
                ext.rc_feedback = nfs_feedback;
                ext.rc_feedback_arg = &nf;
        }

        procnum = nd->nd_procnum;
        if ((nd->nd_flag & ND_NFSV4) &&
            nd->nd_procnum != NFSPROC_NULL &&
            nd->nd_procnum != NFSV4PROC_CBCOMPOUND)
                procnum = NFSV4PROC_COMPOUND;

        if (nmp != NULL) {
                NFSINCRGLOBAL(nfsstatsv1.rpcrequests);

                /* Map the procnum to the old NFSv2 one, as required. */
                if ((nd->nd_flag & ND_NFSV2) != 0) {
                        if (nd->nd_procnum < NFS_V3NPROCS)
                                procnum = nfsv2_procid[nd->nd_procnum];
                        else
                                procnum = NFSV2PROC_NOOP;
                }

                /*
                 * Now only used for the R_DONTRECOVER case, but until that is
                 * supported within the krpc code, I need to keep a queue of
                 * outstanding RPCs for nfsv4 client requests.
                 */
                if ((nd->nd_flag & ND_NFSV4) && procnum == NFSV4PROC_COMPOUND)
                        rep = malloc(sizeof(struct nfsreq),
                            M_NFSDREQ, M_WAITOK);
#ifdef KDTRACE_HOOKS
                if (dtrace_nfscl_nfs234_start_probe != NULL) {
                        uint32_t probe_id;
                        int probe_procnum;

                        if (nd->nd_flag & ND_NFSV4) {
                                probe_id =
                                    nfscl_nfs4_start_probes[nd->nd_procnum];
                                probe_procnum = nd->nd_procnum;
                        } else if (nd->nd_flag & ND_NFSV3) {
                                probe_id = nfscl_nfs3_start_probes[procnum];
                                probe_procnum = procnum;
                        } else {
                                probe_id =
                                    nfscl_nfs2_start_probes[nd->nd_procnum];
                                probe_procnum = procnum;
                        }
                        if (probe_id != 0)
                                (dtrace_nfscl_nfs234_start_probe)
                                    (probe_id, vp, nd->nd_mreq, cred,
                                     probe_procnum);
                }
#endif
        }
        freeslot = -1;          /* Set to slot that needs to be free'd */
tryagain:
        slot = -1;              /* Slot that needs a sequence# increment. */
        /*
         * This timeout specifies when a new socket should be created,
         * along with new xid values. For UDP, this should be done
         * infrequently, since retransmits of RPC requests should normally
         * use the same xid.
         */
        if (nmp == NULL) {
                if (clp == NULL) {
                        timo.tv_sec = NFSV4_UPCALLTIMEO;
                        timo.tv_usec = 0;
                } else {
                        timo.tv_sec = NFSV4_CALLBACKTIMEO / 1000;
                        timo.tv_usec = NFSV4_CALLBACKTIMEO * 1000;
                }
        } else {
                if (nrp->nr_sotype != SOCK_DGRAM) {
                        timo.tv_usec = 0;
                        if ((nmp->nm_flag & NFSMNT_NFSV4))
                                timo.tv_sec = INT_MAX;
                        else
                                timo.tv_sec = NFS_TCPTIMEO;
                } else {
                        if (NFSHASSOFT(nmp)) {
                                /*
                                 * CLSET_RETRIES is set to 2, so this should be
                                 * half of the total timeout required.
                                 */
                                timeo = nmp->nm_retry * nmp->nm_timeo / 2;
                                if (timeo < 1)
                                        timeo = 1;
                                timo.tv_sec = timeo / NFS_HZ;
                                timo.tv_usec = (timeo % NFS_HZ) * 1000000 /
                                    NFS_HZ;
                        } else {
                                /* For UDP hard mounts, use a large value. */
                                timo.tv_sec = NFS_MAXTIMEO / NFS_HZ;
                                timo.tv_usec = 0;
                        }
                }

                if (rep != NULL) {
                        rep->r_flags = 0;
                        rep->r_nmp = nmp;
                        /*
                         * Chain request into list of outstanding requests.
                         */
                        NFSLOCKREQ();
                        TAILQ_INSERT_TAIL(&nfsd_reqq, rep, r_chain);
                        NFSUNLOCKREQ();
                }
        }

        nd->nd_mrep = NULL;
        if (clp != NULL && sep != NULL)
                stat = clnt_bck_call(nrp->nr_client, &ext, procnum,
                    nd->nd_mreq, &nd->nd_mrep, timo, sep->nfsess_xprt);
        else if (nextconn_set)
                /*
                 * When there are multiple TCP connections, send the
                 * RPCs with large messages on the alternate TCP
                 * connection(s) in a round robin fashion.
                 * The small RPC messages are sent on the default
                 * TCP connection because they do not require much
                 * network bandwidth and separating them from the
                 * large RPC messages avoids them getting "log jammed"
                 * behind several large RPC messages.
                 */
                stat = CLNT_CALL_MBUF(nmp->nm_aconn[nextconn],
                    &ext, procnum, nd->nd_mreq, &nd->nd_mrep, timo);
        else
                stat = CLNT_CALL_MBUF(nrp->nr_client, &ext, procnum,
                    nd->nd_mreq, &nd->nd_mrep, timo);
        NFSCL_DEBUG(2, "clnt call=%d\n", stat);

        if (rep != NULL) {
                /*
                 * RPC done, unlink the request.
                 */
                NFSLOCKREQ();
                TAILQ_REMOVE(&nfsd_reqq, rep, r_chain);
                NFSUNLOCKREQ();
        }

        /*
         * If there was a successful reply and a tprintf msg.
         * tprintf a response.
         */
        if (stat == RPC_SUCCESS) {
                error = 0;
        } else if (stat == RPC_TIMEDOUT) {
                NFSINCRGLOBAL(nfsstatsv1.rpctimeouts);
                error = ETIMEDOUT;
        } else if (stat == RPC_VERSMISMATCH) {
                NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
                error = EOPNOTSUPP;
        } else if (stat == RPC_PROGVERSMISMATCH) {
                NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
                error = EPROTONOSUPPORT;
        } else if (stat == RPC_CANTSEND || stat == RPC_CANTRECV ||
             stat == RPC_SYSTEMERROR || stat == RPC_INTR) {
                /* Check for a session slot that needs to be free'd. */
                if ((nd->nd_flag & (ND_NFSV41 | ND_HASSLOTID)) ==
                    (ND_NFSV41 | ND_HASSLOTID) && nmp != NULL &&
                    nd->nd_procnum != NFSPROC_NULL) {
                        /*
                         * This should only occur when either the MDS or
                         * a client has an RPC against a DS fail.
                         * This happens because these cases use "soft"
                         * connections that can time out and fail.
                         * The slot used for this RPC is now in a
                         * non-deterministic state, but if the slot isn't
                         * free'd, threads can get stuck waiting for a slot.
                         */
                        if (sep == NULL)
                                sep = nfsmnt_mdssession(nmp);
                        /*
                         * Bump the sequence# out of range, so that reuse of
                         * this slot will result in an NFSERR_SEQMISORDERED
                         * error and not a bogus cached RPC reply.
                         */
                        mtx_lock(&sep->nfsess_mtx);
                        sep->nfsess_slotseq[nd->nd_slotid] += 10;
                        sep->nfsess_badslots |= (0x1ULL << nd->nd_slotid);
                        mtx_unlock(&sep->nfsess_mtx);
                        /* And free the slot. */
                        nfsv4_freeslot(sep, nd->nd_slotid, true);
                }
                if (stat == RPC_INTR)
                        error = EINTR;
                else {
                        NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
                        error = ENXIO;
                }
        } else if (stat == RPC_AUTHERROR) {
                /* Check for a session slot that needs to be free'd. */
                if ((nd->nd_flag & (ND_NFSV41 | ND_HASSLOTID)) ==
                    (ND_NFSV41 | ND_HASSLOTID) && nmp != NULL &&
                    nd->nd_procnum != NFSPROC_NULL) {
                        /*
                         * This can occur when a Kerberos/RPCSEC_GSS session
                         * expires, due to TGT expiration.
                         * Free the slot, resetting the slot's sequence#.
                         */
                        if (sep == NULL)
                                sep = nfsmnt_mdssession(nmp);
                        nfsv4_freeslot(sep, nd->nd_slotid, true);
                }
                NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
                error = EACCES;
        } else {
                NFSINCRGLOBAL(nfsstatsv1.rpcinvalid);
                error = EACCES;
        }
        if (error) {
                m_freem(nd->nd_mreq);
                if (usegssname == 0)
                        AUTH_DESTROY(auth);
                if (rep != NULL)
                        free(rep, M_NFSDREQ);
                if (set_sigset)
                        newnfs_restore_sigmask(td, &oldset);
                return (error);
        }

        KASSERT(nd->nd_mrep != NULL, ("mrep shouldn't be NULL if no error\n"));

        /*
         * Search for any mbufs that are not a multiple of 4 bytes long
         * or with m_data not longword aligned.
         * These could cause pointer alignment problems, so copy them to
         * well aligned mbufs.
         */
        newnfs_realign(&nd->nd_mrep, M_WAITOK);
        nd->nd_md = nd->nd_mrep;
        nd->nd_dpos = mtod(nd->nd_md, caddr_t);
        nd->nd_repstat = 0;
        if (nd->nd_procnum != NFSPROC_NULL &&
            nd->nd_procnum != NFSV4PROC_CBNULL) {
                /* If sep == NULL, set it to the default in nmp. */
                if (sep == NULL && nmp != NULL)
                        sep = nfsmnt_mdssession(nmp);
                /*
                 * and now the actual NFS xdr.
                 */
                NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                nd->nd_repstat = fxdr_unsigned(u_int32_t, *tl);
                if (nd->nd_repstat >= 10000)
                        NFSCL_DEBUG(1, "proc=%d reps=%d\n", (int)nd->nd_procnum,
                            (int)nd->nd_repstat);

                /*
                 * Get rid of the tag, return count and SEQUENCE result for
                 * NFSv4.
                 */
                if ((nd->nd_flag & ND_NFSV4) != 0 && nd->nd_repstat !=
                    NFSERR_MINORVERMISMATCH) {
                        NFSM_DISSECT(tl, u_int32_t *, NFSX_UNSIGNED);
                        i = fxdr_unsigned(int, *tl);
                        error = nfsm_advance(nd, NFSM_RNDUP(i), -1);
                        if (error)
                                goto nfsmout;
                        NFSM_DISSECT(tl, u_int32_t *, 3 * NFSX_UNSIGNED);
                        opcnt = fxdr_unsigned(int, *tl++);
                        i = fxdr_unsigned(int, *tl++);
                        j = fxdr_unsigned(int, *tl);
                        if (j >= 10000)
                                NFSCL_DEBUG(1, "fop=%d fst=%d\n", i, j);
                        /*
                         * If the first op is Sequence, free up the slot.
                         */
                        if ((nmp != NULL && i == NFSV4OP_SEQUENCE && j != 0) ||
                           (clp != NULL && i == NFSV4OP_CBSEQUENCE && j != 0)) {
                                NFSCL_DEBUG(1, "failed seq=%d\n", j);
                                if (sep != NULL && i == NFSV4OP_SEQUENCE &&
                                    j == NFSERR_SEQMISORDERED) {
                                        mtx_lock(&sep->nfsess_mtx);
                                        sep->nfsess_badslots |=
                                            (0x1ULL << nd->nd_slotid);
                                        mtx_unlock(&sep->nfsess_mtx);
                                }
                        }
                        if (((nmp != NULL && i == NFSV4OP_SEQUENCE && j == 0) ||
                            (clp != NULL && i == NFSV4OP_CBSEQUENCE &&
                            j == 0)) && sep != NULL) {
                                if (i == NFSV4OP_SEQUENCE)
                                        NFSM_DISSECT(tl, uint32_t *,
                                            NFSX_V4SESSIONID +
                                            5 * NFSX_UNSIGNED);
                                else
                                        NFSM_DISSECT(tl, uint32_t *,
                                            NFSX_V4SESSIONID +
                                            4 * NFSX_UNSIGNED);
                                mtx_lock(&sep->nfsess_mtx);
                                if (bcmp(tl, sep->nfsess_sessionid,
                                    NFSX_V4SESSIONID) == 0) {
                                        tl += NFSX_V4SESSIONID / NFSX_UNSIGNED;
                                        retseq = fxdr_unsigned(uint32_t, *tl++);
                                        slot = fxdr_unsigned(int, *tl++);
                                        if ((nd->nd_flag & ND_HASSLOTID) != 0) {
                                                if (slot >= NFSV4_SLOTS ||
                                                    (i == NFSV4OP_CBSEQUENCE &&
                                                     slot >= NFSV4_CBSLOTS)) {
                                                        printf("newnfs_request:"
                                                            " Bogus slot\n");
                                                        slot = nd->nd_slotid;
                                                } else if (slot !=
                                                    nd->nd_slotid) {
                                                    printf("newnfs_request:"
                                                        " Wrong session "
                                                        "srvslot=%d "
                                                        "slot=%d\n", slot,
                                                        nd->nd_slotid);
                                                    if (i == NFSV4OP_SEQUENCE) {
                                                        /*
                                                         * Mark both slots as
                                                         * bad, because we do
                                                         * not know if the
                                                         * server has advanced
                                                         * the sequence# for
                                                         * either of them.
                                                         */
                                                        sep->nfsess_badslots |=
                                                            (0x1ULL << slot);
                                                        sep->nfsess_badslots |=
                                                            (0x1ULL <<
                                                             nd->nd_slotid);
                                                    }
                                                    slot = nd->nd_slotid;
                                                }
                                                freeslot = slot;
                                        } else if (slot != 0) {
                                                printf("newnfs_request: Bad "
                                                    "session slot=%d\n", slot);
                                                slot = 0;
                                        }
                                        if (retseq != sep->nfsess_slotseq[slot])
                                                printf("retseq diff 0x%x\n",
                                                    retseq);
                                        retval0 = fxdr_unsigned(uint32_t,*tl++);
                                        retval = fxdr_unsigned(uint32_t, *tl);
                                        if ((retval + 1) < sep->nfsess_foreslots
                                            ) {
                                                sep->nfsess_foreslots = (retval
                                                    + 1);
                                                nfs_resetslots(sep);
                                        } else if ((retval + 1) >
                                            sep->nfsess_foreslots) {
                                                if (retval0 > retval)
                                                        printf("Sess:highest > "
                                                            "target_highest\n");
                                                sep->nfsess_foreslots =
                                                    (retval < NFSV4_SLOTS) ?
                                                    (retval + 1) : NFSV4_SLOTS;
                                        }
                                }
                                mtx_unlock(&sep->nfsess_mtx);

                                /* Grab the op and status for the next one. */
                                if (opcnt > 1) {
                                        NFSM_DISSECT(tl, uint32_t *,
                                            2 * NFSX_UNSIGNED);
                                        i = fxdr_unsigned(int, *tl++);
                                        j = fxdr_unsigned(int, *tl);
                                }
                        }
                }
                if (nd->nd_repstat != 0) {
                        if (nd->nd_repstat == NFSERR_BADSESSION &&
                            nmp != NULL && dssep == NULL &&
                            (nd->nd_flag & ND_NFSV41) != 0) {
                                /*
                                 * If this is a client side MDS RPC, mark
                                 * the MDS session defunct and initiate
                                 * recovery, as required.
                                 * The nfsess_defunct field is protected by
                                 * the NFSLOCKMNT()/nm_mtx lock and not the
                                 * nfsess_mtx lock to simplify its handling,
                                 * for the MDS session. This lock is also
                                 * sufficient for nfsess_sessionid, since it
                                 * never changes in the structure.
                                 */
                                NFSCL_DEBUG(1, "Got badsession\n");
                                NFSLOCKCLSTATE();
                                NFSLOCKMNT(nmp);
                                if (TAILQ_EMPTY(&nmp->nm_sess)) {
                                        NFSUNLOCKMNT(nmp);
                                        NFSUNLOCKCLSTATE();
                                        printf("If server has not rebooted, "
                                            "check NFS clients for unique "
                                            "/etc/hostid's\n");
                                        goto out;
                                }
                                sep = NFSMNT_MDSSESSION(nmp);
                                if (bcmp(sep->nfsess_sessionid, nd->nd_sequence,
                                    NFSX_V4SESSIONID) == 0) {
                                        printf("Initiate recovery. If server "
                                            "has not rebooted, "
                                            "check NFS clients for unique "
                                            "/etc/hostid's\n");
                                        /* Initiate recovery. */
                                        sep->nfsess_defunct = 1;
                                        NFSCL_DEBUG(1, "Marked defunct\n");
                                        if (nmp->nm_clp != NULL) {
                                                nmp->nm_clp->nfsc_flags |=
                                                    NFSCLFLAGS_RECOVER;
                                                wakeup(nmp->nm_clp);
                                        }
                                }
                                NFSUNLOCKCLSTATE();
                                /*
                                 * Sleep for up to 1sec waiting for a new
                                 * session.
                                 */
                                mtx_sleep(&nmp->nm_sess, &nmp->nm_mtx, PZERO,
                                    "nfsbadsess", hz);
                                /*
                                 * Get the session again, in case a new one
                                 * has been created during the sleep.
                                 */
                                sep = NFSMNT_MDSSESSION(nmp);
                                NFSUNLOCKMNT(nmp);
                                if ((nd->nd_flag & ND_LOOPBADSESS) != 0) {
                                        reterr = nfsv4_sequencelookup(nmp, sep,
                                            &slotpos, &maxslot, &slotseq,
                                            sessionid, true);
                                        if (reterr == 0) {
                                                /* Fill in new session info. */
                                                NFSCL_DEBUG(1,
                                                  "Filling in new sequence\n");
                                                tl = nd->nd_sequence;
                                                bcopy(sessionid, tl,
                                                    NFSX_V4SESSIONID);
                                                tl += NFSX_V4SESSIONID /
                                                    NFSX_UNSIGNED;
                                                *tl++ = txdr_unsigned(slotseq);
                                                *tl++ = txdr_unsigned(slotpos);
                                                *tl = txdr_unsigned(maxslot);
                                                nd->nd_slotid = slotpos;
                                                nd->nd_flag |= ND_HASSLOTID;
                                        }
                                        if (reterr == NFSERR_BADSESSION ||
                                            reterr == 0) {
                                                NFSCL_DEBUG(1,
                                                    "Badsession looping\n");
                                                m_freem(nd->nd_mrep);
                                                nd->nd_mrep = NULL;
                                                goto tryagain;
                                        }
                                        nd->nd_repstat = reterr;
                                        NFSCL_DEBUG(1, "Got err=%d\n", reterr);
                                }
                        }
                        /*
                         * When clp != NULL, it is a callback and all
                         * callback operations can be retried for NFSERR_DELAY.
                         */
                        if (((nd->nd_repstat == NFSERR_DELAY ||
                              nd->nd_repstat == NFSERR_GRACE) &&
                             (nd->nd_flag & ND_NFSV4) && (clp != NULL ||
                             (nd->nd_procnum != NFSPROC_DELEGRETURN &&
                             nd->nd_procnum != NFSPROC_SETATTR &&
                             nd->nd_procnum != NFSPROC_READ &&
                             nd->nd_procnum != NFSPROC_READDS &&
                             nd->nd_procnum != NFSPROC_WRITE &&
                             nd->nd_procnum != NFSPROC_WRITEDS &&
                             nd->nd_procnum != NFSPROC_OPEN &&
                             nd->nd_procnum != NFSPROC_OPENLAYGET &&
                             nd->nd_procnum != NFSPROC_CREATE &&
                             nd->nd_procnum != NFSPROC_CREATELAYGET &&
                             nd->nd_procnum != NFSPROC_OPENCONFIRM &&
                             nd->nd_procnum != NFSPROC_OPENDOWNGRADE &&
                             nd->nd_procnum != NFSPROC_CLOSE &&
                             nd->nd_procnum != NFSPROC_LOCK &&
                             nd->nd_procnum != NFSPROC_LOCKU))) ||
                            (nd->nd_repstat == NFSERR_DELAY &&
                             (nd->nd_flag & ND_NFSV4) == 0) ||
                            nd->nd_repstat == NFSERR_RESOURCE ||
                            nd->nd_repstat == NFSERR_RETRYUNCACHEDREP) {
                                /* Clip at NFS_TRYLATERDEL. */
                                if (timespeccmp(&trylater_delay,
                                    &nfs_trylater_max, >))
                                        trylater_delay = nfs_trylater_max;
                                getnanouptime(&waituntil);
                                timespecadd(&waituntil, &trylater_delay,
                                    &waituntil);
                                do {
                                        nfs_catnap(PZERO, 0, "nfstry");
                                        getnanouptime(&ts);
                                } while (timespeccmp(&ts, &waituntil, <));
                                timespecadd(&trylater_delay, &trylater_delay,
                                    &trylater_delay);   /* Double each time. */
                                if (slot != -1) {
                                        mtx_lock(&sep->nfsess_mtx);
                                        sep->nfsess_slotseq[slot]++;
                                        *nd->nd_slotseq = txdr_unsigned(
                                            sep->nfsess_slotseq[slot]);
                                        mtx_unlock(&sep->nfsess_mtx);
                                }
                                m_freem(nd->nd_mrep);
                                nd->nd_mrep = NULL;
                                goto tryagain;
                        }

                        /*
                         * If the File Handle was stale, invalidate the
                         * lookup cache, just in case.
                         * (vp != NULL implies a client side call)
                         */
                        if (nd->nd_repstat == ESTALE && vp != NULL) {
                                cache_purge(vp);
                                if (ncl_call_invalcaches != NULL)
                                        (*ncl_call_invalcaches)(vp);
                        }
                }
                if ((nd->nd_flag & ND_NFSV4) != 0) {
                        /* Free the slot, as required. */
                        if (freeslot != -1)
                                nfsv4_freeslot(sep, freeslot, false);
                        /*
                         * If this op is Putfh, throw its results away.
                         */
                        if (j >= 10000)
                                NFSCL_DEBUG(1, "nop=%d nst=%d\n", i, j);
                        if (nmp != NULL && i == NFSV4OP_PUTFH && j == 0) {
                                NFSM_DISSECT(tl,u_int32_t *,2 * NFSX_UNSIGNED);
                                i = fxdr_unsigned(int, *tl++);
                                j = fxdr_unsigned(int, *tl);
                                if (j >= 10000)
                                        NFSCL_DEBUG(1, "n2op=%d n2st=%d\n", i,
                                            j);
                                /*
                                 * All Compounds that do an Op that must
                                 * be in sequence consist of NFSV4OP_PUTFH
                                 * followed by one of these. As such, we
                                 * can determine if the seqid# should be
                                 * incremented, here.
                                 */
                                if ((i == NFSV4OP_OPEN ||
                                     i == NFSV4OP_OPENCONFIRM ||
                                     i == NFSV4OP_OPENDOWNGRADE ||
                                     i == NFSV4OP_CLOSE ||
                                     i == NFSV4OP_LOCK ||
                                     i == NFSV4OP_LOCKU) &&
                                    (j == 0 ||
                                     (j != NFSERR_STALECLIENTID &&
                                      j != NFSERR_STALESTATEID &&
                                      j != NFSERR_BADSTATEID &&
                                      j != NFSERR_BADSEQID &&
                                      j != NFSERR_BADXDR &&      
                                      j != NFSERR_RESOURCE &&
                                      j != NFSERR_NOFILEHANDLE)))                
                                        nd->nd_flag |= ND_INCRSEQID;
                        }
                        /*
                         * If this op's status is non-zero, mark
                         * that there is no more data to process.
                         * The exception is Setattr, which always has xdr
                         * when it has failed.
                         */
                        if (j != 0 && i != NFSV4OP_SETATTR)
                                nd->nd_flag |= ND_NOMOREDATA;

                        /*
                         * If R_DONTRECOVER is set, replace the stale error
                         * reply, so that recovery isn't initiated.
                         */
                        if ((nd->nd_repstat == NFSERR_STALECLIENTID ||
                             nd->nd_repstat == NFSERR_BADSESSION ||
                             nd->nd_repstat == NFSERR_STALESTATEID) &&
                            rep != NULL && (rep->r_flags & R_DONTRECOVER))
                                nd->nd_repstat = NFSERR_STALEDONTRECOVER;
                }
        }
out:

#ifdef KDTRACE_HOOKS
        if (nmp != NULL && dtrace_nfscl_nfs234_done_probe != NULL) {
                uint32_t probe_id;
                int probe_procnum;

                if (nd->nd_flag & ND_NFSV4) {
                        probe_id = nfscl_nfs4_done_probes[nd->nd_procnum];
                        probe_procnum = nd->nd_procnum;
                } else if (nd->nd_flag & ND_NFSV3) {
                        probe_id = nfscl_nfs3_done_probes[procnum];
                        probe_procnum = procnum;
                } else {
                        probe_id = nfscl_nfs2_done_probes[nd->nd_procnum];
                        probe_procnum = procnum;
                }
                if (probe_id != 0)
                        (dtrace_nfscl_nfs234_done_probe)(probe_id, vp,
                            nd->nd_mreq, cred, probe_procnum, 0);
        }
#endif

        m_freem(nd->nd_mreq);
        if (usegssname == 0)
                AUTH_DESTROY(auth);
        if (rep != NULL)
                free(rep, M_NFSDREQ);
        if (set_sigset)
                newnfs_restore_sigmask(td, &oldset);
        return (0);
nfsmout:
        m_freem(nd->nd_mrep);
        m_freem(nd->nd_mreq);
        if (usegssname == 0)
                AUTH_DESTROY(auth);
        if (rep != NULL)
                free(rep, M_NFSDREQ);
        if (set_sigset)
                newnfs_restore_sigmask(td, &oldset);
        return (error);
}

/*
 * Reset slots above nfsess_foreslots that are not busy.
 */
void
nfs_resetslots(struct nfsclsession *sep)
{
        int i;
        uint64_t bitval;

        mtx_assert(&sep->nfsess_mtx, MA_OWNED);
        bitval = (1 << sep->nfsess_foreslots);
        for (i = sep->nfsess_foreslots; i < NFSV4_SLOTS; i++) {
                if ((sep->nfsess_slots & bitval) == 0 &&
                    (sep->nfsess_badslots & bitval) == 0)
                        sep->nfsess_slotseq[i] = 0;
                bitval <<= 1;
        }
}

/*
 * Mark all of an nfs mount's outstanding requests with R_SOFTTERM and
 * wait for all requests to complete. This is used by forced unmounts
 * to terminate any outstanding RPCs.
 */
int
newnfs_nmcancelreqs(struct nfsmount *nmp)
{
        struct nfsclds *dsp;
        struct __rpc_client *cl;
        int i;

        if (nmp->nm_sockreq.nr_client != NULL)
                CLNT_CLOSE(nmp->nm_sockreq.nr_client);
        for (i = 0; i < nmp->nm_aconnect; i++)
                if (nmp->nm_aconn[i] != NULL)
                        CLNT_CLOSE(nmp->nm_aconn[i]);
lookformore:
        NFSLOCKMNT(nmp);
        TAILQ_FOREACH(dsp, &nmp->nm_sess, nfsclds_list) {
                NFSLOCKDS(dsp);
                if (dsp != TAILQ_FIRST(&nmp->nm_sess) &&
                    (dsp->nfsclds_flags & NFSCLDS_CLOSED) == 0 &&
                    dsp->nfsclds_sockp != NULL &&
                    dsp->nfsclds_sockp->nr_client != NULL) {
                        dsp->nfsclds_flags |= NFSCLDS_CLOSED;
                        cl = dsp->nfsclds_sockp->nr_client;
                        NFSUNLOCKDS(dsp);
                        NFSUNLOCKMNT(nmp);
                        CLNT_CLOSE(cl);
                        goto lookformore;
                }
                NFSUNLOCKDS(dsp);
        }
        NFSUNLOCKMNT(nmp);
        return (0);
}

/*
 * Any signal that can interrupt an NFS operation in an intr mount
 * should be added to this set. SIGSTOP and SIGKILL cannot be masked.
 */
int newnfs_sig_set[] = {
        SIGINT,
        SIGTERM,
        SIGHUP,
        SIGKILL,
        SIGQUIT
};

/*
 * Check to see if one of the signals in our subset is pending on
 * the process (in an intr mount).
 */
static int
nfs_sig_pending(sigset_t set)
{
        int i;

        for (i = 0 ; i < nitems(newnfs_sig_set); i++)
                if (SIGISMEMBER(set, newnfs_sig_set[i]))
                        return (1);
        return (0);
}

/*
 * The set/restore sigmask functions are used to (temporarily) overwrite
 * the thread td_sigmask during an RPC call (for example). These are also
 * used in other places in the NFS client that might tsleep().
 */
void
newnfs_set_sigmask(struct thread *td, sigset_t *oldset)
{
        sigset_t newset;
        int i;
        struct proc *p;

        SIGFILLSET(newset);
        if (td == NULL)
                td = curthread; /* XXX */
        p = td->td_proc;
        /* Remove the NFS set of signals from newset */
        PROC_LOCK(p);
        mtx_lock(&p->p_sigacts->ps_mtx);
        for (i = 0 ; i < nitems(newnfs_sig_set); i++) {
                /*
                 * But make sure we leave the ones already masked
                 * by the process, ie. remove the signal from the
                 * temporary signalmask only if it wasn't already
                 * in p_sigmask.
                 */
                if (!SIGISMEMBER(td->td_sigmask, newnfs_sig_set[i]) &&
                    !SIGISMEMBER(p->p_sigacts->ps_sigignore, newnfs_sig_set[i]))
                        SIGDELSET(newset, newnfs_sig_set[i]);
        }
        mtx_unlock(&p->p_sigacts->ps_mtx);
        kern_sigprocmask(td, SIG_SETMASK, &newset, oldset,
            SIGPROCMASK_PROC_LOCKED);
        PROC_UNLOCK(p);
}

void
newnfs_restore_sigmask(struct thread *td, sigset_t *set)
{
        if (td == NULL)
                td = curthread; /* XXX */
        kern_sigprocmask(td, SIG_SETMASK, set, NULL, 0);
}

/*
 * NFS wrapper to msleep(), that shoves a new p_sigmask and restores the
 * old one after msleep() returns.
 */
int
newnfs_msleep(struct thread *td, void *ident, struct mtx *mtx, int priority, char *wmesg, int timo)
{
        sigset_t oldset;
        int error;

        if ((priority & PCATCH) == 0)
                return msleep(ident, mtx, priority, wmesg, timo);
        if (td == NULL)
                td = curthread; /* XXX */
        newnfs_set_sigmask(td, &oldset);
        error = msleep(ident, mtx, priority, wmesg, timo);
        newnfs_restore_sigmask(td, &oldset);
        return (error);
}

/*
 * Test for a termination condition pending on the process.
 * This is used for NFSMNT_INT mounts.
 */
int
newnfs_sigintr(struct nfsmount *nmp, struct thread *td)
{
        struct proc *p;
        sigset_t tmpset;

        /* Terminate all requests while attempting a forced unmount. */
        if (NFSCL_FORCEDISM(nmp->nm_mountp))
                return (EIO);
        if (!(nmp->nm_flag & NFSMNT_INT))
                return (0);
        if (td == NULL)
                return (0);
        p = td->td_proc;
        PROC_LOCK(p);
        tmpset = p->p_siglist;
        SIGSETOR(tmpset, td->td_siglist);
        SIGSETNAND(tmpset, td->td_sigmask);
        mtx_lock(&p->p_sigacts->ps_mtx);
        SIGSETNAND(tmpset, p->p_sigacts->ps_sigignore);
        mtx_unlock(&p->p_sigacts->ps_mtx);
        if ((SIGNOTEMPTY(p->p_siglist) || SIGNOTEMPTY(td->td_siglist))
            && nfs_sig_pending(tmpset)) {
                PROC_UNLOCK(p);
                return (EINTR);
        }
        PROC_UNLOCK(p);
        return (0);
}

static int
nfs_msg(struct thread *td, const char *server, const char *msg, int error)
{
        struct proc *p;

        p = td ? td->td_proc : NULL;
        if (error) {
                tprintf(p, LOG_INFO, "nfs server %s: %s, error %d\n",
                    server, msg, error);
        } else {
                tprintf(p, LOG_INFO, "nfs server %s: %s\n", server, msg);
        }
        return (0);
}

static void
nfs_down(struct nfsmount *nmp, struct thread *td, const char *msg,
    int error, int flags)
{
        if (nmp == NULL)
                return;
        mtx_lock(&nmp->nm_mtx);
        if ((flags & NFSSTA_TIMEO) && !(nmp->nm_state & NFSSTA_TIMEO)) {
                nmp->nm_state |= NFSSTA_TIMEO;
                mtx_unlock(&nmp->nm_mtx);
                vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
                    VQ_NOTRESP, 0);
        } else
                mtx_unlock(&nmp->nm_mtx);
        mtx_lock(&nmp->nm_mtx);
        if ((flags & NFSSTA_LOCKTIMEO) && !(nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                nmp->nm_state |= NFSSTA_LOCKTIMEO;
                mtx_unlock(&nmp->nm_mtx);
                vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
                    VQ_NOTRESPLOCK, 0);
        } else
                mtx_unlock(&nmp->nm_mtx);
        nfs_msg(td, nmp->nm_mountp->mnt_stat.f_mntfromname, msg, error);
}

static void
nfs_up(struct nfsmount *nmp, struct thread *td, const char *msg,
    int flags, int tprintfmsg)
{
        if (nmp == NULL)
                return;
        if (tprintfmsg) {
                nfs_msg(td, nmp->nm_mountp->mnt_stat.f_mntfromname, msg, 0);
        }

        mtx_lock(&nmp->nm_mtx);
        if ((flags & NFSSTA_TIMEO) && (nmp->nm_state & NFSSTA_TIMEO)) {
                nmp->nm_state &= ~NFSSTA_TIMEO;
                mtx_unlock(&nmp->nm_mtx);
                vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
                    VQ_NOTRESP, 1);
        } else
                mtx_unlock(&nmp->nm_mtx);

        mtx_lock(&nmp->nm_mtx);
        if ((flags & NFSSTA_LOCKTIMEO) && (nmp->nm_state & NFSSTA_LOCKTIMEO)) {
                nmp->nm_state &= ~NFSSTA_LOCKTIMEO;
                mtx_unlock(&nmp->nm_mtx);
                vfs_event_signal(&nmp->nm_mountp->mnt_stat.f_fsid,
                    VQ_NOTRESPLOCK, 1);
        } else
                mtx_unlock(&nmp->nm_mtx);
}