/*      $NetBSD: nfs_syscalls.c,v 1.165 2026/06/18 19:56:09 christos Exp $      */

/*
 * Copyright (c) 1989, 1993
 *      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.
 *
 *      @(#)nfs_syscalls.c      8.5 (Berkeley) 3/30/95
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: nfs_syscalls.c,v 1.165 2026/06/18 19:56:09 christos Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/kmem.h>
#include <sys/buf.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/signalvar.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/namei.h>
#include <sys/syslog.h>
#include <sys/filedesc.h>
#include <sys/kthread.h>
#include <sys/kauth.h>
#include <sys/syscallargs.h>
#include <sys/cprng.h>
#include <sys/rbtree.h>

#include <netinet/in.h>
#include <netinet/tcp.h>
#include <nfs/xdr_subs.h>
#include <nfs/rpcv2.h>
#include <nfs/nfsproto.h>
#include <nfs/nfs.h>
#include <nfs/nfsm_subs.h>
#include <nfs/nfsrvcache.h>
#include <nfs/nfsmount.h>
#include <nfs/nfsnode.h>
#include <nfs/nfsrtt.h>
#include <nfs/nfs_var.h>

extern int32_t (*nfsrv3_procs[NFS_NPROCS])(struct nfsrv_descript *,
                                                struct nfssvc_sock *,
                                                struct lwp *, struct mbuf **);
extern int nfsrvw_procrastinate;
extern int nuidhash_max;

static int nfs_numnfsd = 0;
static struct nfsdrt nfsdrt;
kmutex_t nfsd_lock;
struct nfssvc_sockhead nfssvc_sockhead;
kcondvar_t nfsd_initcv;
struct nfssvc_sockhead nfssvc_sockpending;
struct nfsdidlehead nfsd_idle_head;

static rb_tree_t nfsd_tree;
static const rb_tree_ops_t nfsd_tree_ops;

int nfssvc_sockhead_flag;
int nfsd_head_flag;

struct nfssvc_sock *nfs_udpsock;
struct nfssvc_sock *nfs_udp6sock;

static struct nfssvc_sock *nfsrv_sockalloc(void);
static void nfsrv_sockfree(struct nfssvc_sock *);
static void nfsd_rt(int, struct nfsrv_descript *, int);
static int nfssvc_nfsd(struct nfssvc_copy_ops *, struct nfsd_srvargs *, void *,
                struct lwp *);

static int nfsd_compare_nodes(void *, const void *, const void *);
static int nfsd_compare_key(void *, const void *, const void *);

static struct nfsd *nfsd_bake_cookie(struct nfsd *);
static void nfsd_toss_cookie(struct nfsd *);
static struct nfsd *nfsd_get(struct nfsd *);

static int nfssvc_addsock_in(struct nfsd_args *, const void *);
static int nfssvc_setexports_in(struct mountd_exports_list *, const void *);
static int nfssvc_nsd_in(struct nfsd_srvargs *, const void *);
static int nfssvc_nsd_out(void *, const struct nfsd_srvargs *);
static int nfssvc_exp_in(struct export_args *, const void *, size_t);

static const rb_tree_ops_t nfsd_tree_ops = {
        .rbto_compare_nodes = nfsd_compare_nodes,
        .rbto_compare_key = nfsd_compare_key,
        .rbto_node_offset = offsetof(struct nfsd, nfsd_node),
};

static int
nfsd_compare_nodes(void *cookie, const void *va, const void *vb)
{
        const struct nfsd *na = va;
        const struct nfsd *nb = vb;

        if (na->nfsd_cookie < nb->nfsd_cookie)
                return -1;
        if (na->nfsd_cookie > nb->nfsd_cookie)
                return +1;
        return 0;
}

static int
nfsd_compare_key(void *cookie, const void *vn, const void *vk)
{
        const struct nfsd *n = vn;
        const uint32_t *k = vk;

        if (n->nfsd_cookie < *k)
                return -1;
        if (n->nfsd_cookie > *k)
                return +1;
        return 0;
}

/*
 * nfsd_bake_cookie(nfsd)
 *
 *      Bake a cookie for nfsd, hang it on the tree of nfsds, and
 *      return a userland-safe pointer nfsdu neatly packed for
 *      transport in struct nfsd_srvargs::nsd_nfsd.
 */
static struct nfsd *
nfsd_bake_cookie(struct nfsd *nfsd)
{

        KASSERT(mutex_owned(&nfsd_lock));

        do {
                nfsd->nfsd_cookie = cprng_fast32();
        } while (nfsd->nfsd_cookie == 0 ||
            rb_tree_insert_node(&nfsd_tree, nfsd) != nfsd);

        return (struct nfsd *)(uintptr_t)nfsd->nfsd_cookie;
}

/*
 * nfsd_toss_cookie(nfsd)
 *
 *      Toss nfsd's cookie.
 */
static void
nfsd_toss_cookie(struct nfsd *nfsd)
{

        KASSERT(mutex_owned(&nfsd_lock));
        KASSERT(nfsd->nfsd_cookie != 0);

        rb_tree_remove_node(&nfsd_tree, nfsd);
        nfsd->nfsd_cookie = 0;  /* paranoia */
}

/*
 * nfsd_get(nfsdu)
 *
 *      Return the struct nfsd pointer for the userland nfsdu cookie,
 *      as stored in struct nfsd_srvargs::nsd_nfsd, or NULL if nfsdu is
 *      not a current valid nfsd cookie.
 *
 *      Caller MUST NOT hold nfsd_lock.  Caller MUST NOT pass (struct
 *      nfsd *)(uintptr_t)0, which is the sentinel value for no nfsd
 *      cookie, for which the caller should check first.
 */
static struct nfsd *
nfsd_get(struct nfsd *nfsdu)
{
        uintptr_t cookie = (uintptr_t)nfsdu;
        uint32_t key;
        struct nfsd *nfsd;

        KASSERT(cookie != 0);
        if (cookie > UINT32_MAX)
                return NULL;
        key = cookie;

        mutex_enter(&nfsd_lock);
        nfsd = rb_tree_find_node(&nfsd_tree, &key);
        mutex_exit(&nfsd_lock);

        return nfsd;
}

static int
nfssvc_addsock_in(struct nfsd_args *nfsdarg, const void *argp)
{

        return copyin(argp, nfsdarg, sizeof *nfsdarg);
}

static int
nfssvc_setexports_in(struct mountd_exports_list *mel, const void *argp)
{

        return copyin(argp, mel, sizeof *mel);
}

static int
nfssvc_nsd_in(struct nfsd_srvargs *nsd, const void *argp)
{

        return copyin(argp, nsd, sizeof *nsd);
}

static int
nfssvc_nsd_out(void *argp, const struct nfsd_srvargs *nsd)
{

        return copyout(nsd, argp, sizeof *nsd);
}

static int
nfssvc_exp_in(struct export_args *exp, const void *argp, size_t nexports)
{

        return copyin(argp, exp, sizeof(*exp) * nexports);
}

/*
 * NFS server system calls
 */

static struct nfssvc_copy_ops native_ops = {
        .addsock_in = nfssvc_addsock_in,
        .setexports_in = nfssvc_setexports_in,
        .nsd_in = nfssvc_nsd_in,
        .nsd_out = nfssvc_nsd_out,
        .exp_in = nfssvc_exp_in,
};

/*
 * Nfs server pseudo system call for the nfsd's
 * Based on the flag value it either:
 * - adds a socket to the selection list
 * - remains in the kernel as an nfsd
 * - remains in the kernel as an nfsiod
 */

int
sys_nfssvc(struct lwp *l, const struct sys_nfssvc_args *uap, register_t *retval)
{
        /* {
                syscallarg(int) flag;
                syscallarg(void *) argp;
        } */
        int     flag = SCARG(uap, flag);
        void    *argp = SCARG(uap, argp);

        return do_nfssvc(&native_ops, l, flag, argp, retval);
}

int
do_nfssvc(struct nfssvc_copy_ops *ops, struct lwp *l, int flag, void *argp, register_t *retval)
{
        int error;
        file_t *fp;
        struct mbuf *nam;
        struct nfsd_args nfsdarg;
        struct nfsd_srvargs nfsd_srvargs, *nsd = &nfsd_srvargs;
        struct nfsd *nfsd = NULL;
        struct nfssvc_sock *slp;
        struct nfsuid *nuidp;

        error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_NFS,
            KAUTH_REQ_NETWORK_NFS_SVC, NULL, NULL, NULL);
        if (error)
                return (error);

        mutex_enter(&nfsd_lock);
        while (nfssvc_sockhead_flag & SLP_INIT) {
                cv_wait(&nfsd_initcv, &nfsd_lock);
        }
        mutex_exit(&nfsd_lock);

        if (flag & NFSSVC_BIOD) {
                /* Dummy implementation of nfsios for 1.4 and earlier. */
                error = kpause("nfsbiod", true, 0, NULL);
        } else if (flag & NFSSVC_MNTD) {
                error = ENOSYS;
        } else if (flag & NFSSVC_ADDSOCK) {
                error = ops->addsock_in(&nfsdarg, argp);
                if (error)
                        return (error);
                /* getsock() will use the descriptor for us */
                if ((fp = fd_getfile(nfsdarg.sock)) == NULL)
                        return (EBADF);
                if (fp->f_type != DTYPE_SOCKET) {
                        fd_putfile(nfsdarg.sock);
                        return (ENOTSOCK);
                }
                /*
                 * Get the client address for connected sockets.
                 */
                if (nfsdarg.name == NULL || nfsdarg.namelen == 0)
                        nam = (struct mbuf *)0;
                else {
                        error = sockargs(&nam, nfsdarg.name, nfsdarg.namelen,
                                UIO_USERSPACE, MT_SONAME);
                        if (error) {
                                fd_putfile(nfsdarg.sock);
                                return (error);
                        }
                }
                error = nfssvc_addsock(fp, nam);
                fd_putfile(nfsdarg.sock);
        } else if (flag & (NFSSVC_SETEXPORTSLIST | NFSSVC_REPLACEEXPORTSLIST)) {
                struct export_args *args;
                struct mountd_exports_list mel;

                error = ops->setexports_in(&mel, argp);
                if (error != 0)
                        return error;

                args = (struct export_args *)malloc(mel.mel_nexports *
                    sizeof(struct export_args), M_TEMP, M_WAITOK);
                error = ops->exp_in(args, mel.mel_exports, mel.mel_nexports);
                if (error != 0) {
                        free(args, M_TEMP);
                        return error;
                }
                mel.mel_exports = args;

                error = mountd_set_exports_list(&mel, l, NULL,
                    flag & (NFSSVC_SETEXPORTSLIST | NFSSVC_REPLACEEXPORTSLIST));

                free(args, M_TEMP);
        } else {
                error = ops->nsd_in(nsd, argp);
                if (error)
                        return (error);
                if ((uintptr_t)nsd->nsd_nfsd != 0 &&
                    (nfsd = nfsd_get(nsd->nsd_nfsd)) == NULL)
                        return (EINVAL);
                if ((flag & NFSSVC_AUTHIN) &&
                    nfsd != NULL &&
                    (nfsd->nfsd_slp->ns_flags & SLP_VALID)) {
                        slp = nfsd->nfsd_slp;

                        /*
                         * First check to see if another nfsd has already
                         * added this credential.
                         */
                        LIST_FOREACH(nuidp, NUIDHASH(slp, nsd->nsd_cr.cr_uid),
                            nu_hash) {
                                if (kauth_cred_geteuid(nuidp->nu_cr) ==
                                    nsd->nsd_cr.cr_uid &&
                                    (!nfsd->nfsd_nd->nd_nam2 ||
                                     netaddr_match(NU_NETFAM(nuidp),
                                     &nuidp->nu_haddr, nfsd->nfsd_nd->nd_nam2)))
                                        break;
                        }
                        if (nuidp) {
                            kauth_cred_hold(nuidp->nu_cr);
                            nfsd->nfsd_nd->nd_cr = nuidp->nu_cr;
                            nfsd->nfsd_nd->nd_flag |= ND_KERBFULL;
                        } else {
                            /*
                             * Nope, so we will.
                             */
                            if (slp->ns_numuids < nuidhash_max) {
                                slp->ns_numuids++;
                                nuidp = kmem_alloc(sizeof(*nuidp), KM_SLEEP);
                            } else
                                nuidp = (struct nfsuid *)0;
                            if ((slp->ns_flags & SLP_VALID) == 0) {
                                if (nuidp)
                                    kmem_free(nuidp, sizeof(*nuidp));
                            } else {
                                if (nuidp == (struct nfsuid *)0) {
                                    nuidp = TAILQ_FIRST(&slp->ns_uidlruhead);
                                    LIST_REMOVE(nuidp, nu_hash);
                                    TAILQ_REMOVE(&slp->ns_uidlruhead, nuidp,
                                        nu_lru);
                                    if (nuidp->nu_flag & NU_NAM)
                                        m_freem(nuidp->nu_nam);
                                }
                                nuidp->nu_flag = 0;
                                kauth_uucred_to_cred(nuidp->nu_cr,
                                    &nsd->nsd_cr);
                                nuidp->nu_timestamp = nsd->nsd_timestamp;
                                nuidp->nu_expire = time_second + nsd->nsd_ttl;
                                /*
                                 * and save the session key in nu_key.
                                 */
                                memcpy(nuidp->nu_key, nsd->nsd_key,
                                    sizeof(nsd->nsd_key));
                                if (nfsd->nfsd_nd->nd_nam2) {
                                    struct sockaddr_in *saddr;

                                    saddr = mtod(nfsd->nfsd_nd->nd_nam2,
                                         struct sockaddr_in *);
                                    switch (saddr->sin_family) {
                                    case AF_INET:
                                        nuidp->nu_flag |= NU_INETADDR;
                                        nuidp->nu_inetaddr =
                                             saddr->sin_addr.s_addr;
                                        break;
                                    case AF_INET6:
                                        nuidp->nu_flag |= NU_NAM;
                                        nuidp->nu_nam = m_copym(
                                            nfsd->nfsd_nd->nd_nam2, 0,
                                             M_COPYALL, M_WAIT);
                                        break;
                                    default:
                                        kmem_free(nuidp, sizeof(*nuidp));
                                        return EAFNOSUPPORT;
                                    };
                                }
                                TAILQ_INSERT_TAIL(&slp->ns_uidlruhead, nuidp,
                                        nu_lru);
                                LIST_INSERT_HEAD(NUIDHASH(slp, nsd->nsd_uid),
                                        nuidp, nu_hash);
                                kauth_cred_hold(nuidp->nu_cr);
                                nfsd->nfsd_nd->nd_cr = nuidp->nu_cr;
                                nfsd->nfsd_nd->nd_flag |= ND_KERBFULL;
                            }
                        }
                }
                if ((flag & NFSSVC_AUTHINFAIL) &&
                    nfsd != NULL)
                        nfsd->nfsd_flag |= NFSD_AUTHFAIL;
                error = nfssvc_nfsd(ops, nsd, argp, l);
        }
        if (error == EINTR || error == ERESTART)
                error = 0;
        return (error);
}

static struct nfssvc_sock *
nfsrv_sockalloc(void)
{
        struct nfssvc_sock *slp;

        slp = kmem_alloc(sizeof(*slp), KM_SLEEP);
        memset(slp, 0, sizeof (struct nfssvc_sock));
        mutex_init(&slp->ns_lock, MUTEX_DRIVER, IPL_SOFTNET);
        mutex_init(&slp->ns_alock, MUTEX_DRIVER, IPL_SOFTNET);
        cv_init(&slp->ns_cv, "nfsdsock");
        TAILQ_INIT(&slp->ns_uidlruhead);
        LIST_INIT(&slp->ns_tq);
        SIMPLEQ_INIT(&slp->ns_sendq);
        mutex_enter(&nfsd_lock);
        TAILQ_INSERT_TAIL(&nfssvc_sockhead, slp, ns_chain);
        mutex_exit(&nfsd_lock);

        return slp;
}

static void
nfsrv_sockfree(struct nfssvc_sock *slp)
{

        KASSERT(slp->ns_so == NULL);
        KASSERT(slp->ns_fp == NULL);
        KASSERT((slp->ns_flags & SLP_VALID) == 0);
        mutex_destroy(&slp->ns_lock);
        mutex_destroy(&slp->ns_alock);
        cv_destroy(&slp->ns_cv);
        kmem_free(slp, sizeof(*slp));
}

/*
 * Adds a socket to the list for servicing by nfsds.
 */
int
nfssvc_addsock(file_t *fp, struct mbuf *mynam)
{
        int siz;
        struct nfssvc_sock *slp;
        struct socket *so;
        struct nfssvc_sock *tslp;
        int error;
        int val;

        so = fp->f_socket;
        tslp = (struct nfssvc_sock *)0;
        /*
         * Add it to the list, as required.
         */
        if (so->so_proto->pr_protocol == IPPROTO_UDP) {
                if (so->so_proto->pr_domain->dom_family == AF_INET6)
                        tslp = nfs_udp6sock;
                else {
                        tslp = nfs_udpsock;
                        if (tslp->ns_flags & SLP_VALID) {
                                m_freem(mynam);
                                return (EPERM);
                        }
                }
        }
        if (so->so_type == SOCK_STREAM)
                siz = NFS_MAXPACKET + sizeof (u_long);
        else
                siz = NFS_MAXPACKET;
        solock(so);
        error = soreserve(so, siz, siz);
        sounlock(so);
        if (error) {
                m_freem(mynam);
                return (error);
        }

        /*
         * Set protocol specific options { for now TCP only } and
         * reserve some space. For datagram sockets, this can get called
         * repeatedly for the same socket, but that isn't harmful.
         */
        if (so->so_type == SOCK_STREAM) {
                val = 1;
                so_setsockopt(NULL, so, SOL_SOCKET, SO_KEEPALIVE, &val,
                    sizeof(val));
        }
        if ((so->so_proto->pr_domain->dom_family == AF_INET ||
            so->so_proto->pr_domain->dom_family == AF_INET6) &&
            so->so_proto->pr_protocol == IPPROTO_TCP) {
                val = 1;
                so_setsockopt(NULL, so, IPPROTO_TCP, TCP_NODELAY, &val,
                    sizeof(val));
        }
        solock(so);
        so->so_rcv.sb_flags &= ~SB_NOINTR;
        so->so_rcv.sb_timeo = 0;
        so->so_snd.sb_flags &= ~SB_NOINTR;
        so->so_snd.sb_timeo = 0;
        sounlock(so);
        if (tslp) {
                slp = tslp;
        } else {
                slp = nfsrv_sockalloc();
        }
        slp->ns_so = so;
        slp->ns_nam = mynam;
        mutex_enter(&fp->f_lock);
        fp->f_count++;
        mutex_exit(&fp->f_lock);
        slp->ns_fp = fp;
        slp->ns_flags = SLP_VALID;
        slp->ns_aflags = SLP_A_NEEDQ;
        slp->ns_gflags = 0;
        slp->ns_sflags = 0;
        solock(so);
        so->so_upcallarg = (void *)slp;
        so->so_upcall = nfsrv_soupcall;
        so->so_rcv.sb_flags |= SB_UPCALL;
        sounlock(so);
        nfsrv_wakenfsd(slp);
        return (0);
}

/*
 * Called by nfssvc() for nfsds. Just loops around servicing rpc requests
 * until it is killed by a signal.
 */
static int
nfssvc_nfsd(struct nfssvc_copy_ops *ops, struct nfsd_srvargs *nsd,
            void *argp, struct lwp *l)
{
        struct timeval tv;
        struct mbuf *m;
        struct nfssvc_sock *slp;
        struct nfsd *nfsd;
        struct nfsrv_descript *nd = NULL;
        struct mbuf *mreq;
        u_quad_t cur_usec;
        int error = 0, cacherep, siz, sotype, writes_todo;
        struct proc *p = l->l_proc;
        bool doreinit;

#ifndef nolint
        cacherep = RC_DOIT;
        writes_todo = 0;
#endif
        /*
         * If userland didn't provide an nfsd cookie, bake a fresh one;
         * if they did provide one, look it up.
         */
        if ((uintptr_t)nsd->nsd_nfsd == 0) {
                nfsd = kmem_alloc(sizeof(*nfsd), KM_SLEEP);
                memset(nfsd, 0, sizeof (struct nfsd));
                cv_init(&nfsd->nfsd_cv, "nfsd");
                nfsd->nfsd_procp = p;
                mutex_enter(&nfsd_lock);
                while ((nfssvc_sockhead_flag & SLP_INIT) != 0) {
                        KASSERT(nfs_numnfsd == 0);
                        cv_wait(&nfsd_initcv, &nfsd_lock);
                }
                nsd->nsd_nfsd = nfsd_bake_cookie(nfsd);
                nfs_numnfsd++;
                mutex_exit(&nfsd_lock);
        } else if ((nfsd = nfsd_get(nsd->nsd_nfsd)) == NULL) {
                return (EINVAL);
        }
        KASSERT(nfsd != NULL);
        KASSERT(nsd->nsd_nfsd != (struct nfsd *)(uintptr_t)0);

        /*
         * Loop getting rpc requests until SIGKILL.
         */
        for (;;) {
                bool dummy;

                preempt_point();

                if (nfsd->nfsd_slp == NULL) {
                        mutex_enter(&nfsd_lock);
                        while (nfsd->nfsd_slp == NULL &&
                            (nfsd_head_flag & NFSD_CHECKSLP) == 0) {
                                SLIST_INSERT_HEAD(&nfsd_idle_head, nfsd,
                                    nfsd_idle);
                                error = cv_wait_sig(&nfsd->nfsd_cv, &nfsd_lock);
                                if (error) {
                                        slp = nfsd->nfsd_slp;
                                        nfsd->nfsd_slp = NULL;
                                        if (!slp)
                                                SLIST_REMOVE(&nfsd_idle_head,
                                                    nfsd, nfsd, nfsd_idle);
                                        mutex_exit(&nfsd_lock);
                                        if (slp) {
                                                nfsrv_wakenfsd(slp);
                                                nfsrv_slpderef(slp);
                                        }
                                        goto done;
                                }
                        }
                        if (nfsd->nfsd_slp == NULL &&
                            (nfsd_head_flag & NFSD_CHECKSLP) != 0) {
                                slp = TAILQ_FIRST(&nfssvc_sockpending);
                                if (slp) {
                                        KASSERT((slp->ns_gflags & SLP_G_DOREC)
                                            != 0);
                                        TAILQ_REMOVE(&nfssvc_sockpending, slp,
                                            ns_pending);
                                        slp->ns_gflags &= ~SLP_G_DOREC;
                                        slp->ns_sref++;
                                        nfsd->nfsd_slp = slp;
                                } else
                                        nfsd_head_flag &= ~NFSD_CHECKSLP;
                        }
                        KASSERT(nfsd->nfsd_slp == NULL ||
                            nfsd->nfsd_slp->ns_sref > 0);
                        mutex_exit(&nfsd_lock);
                        if ((slp = nfsd->nfsd_slp) == NULL)
                                continue;
                        if (slp->ns_flags & SLP_VALID) {
                                bool more;

                                if (nfsdsock_testbits(slp, SLP_A_NEEDQ)) {
                                        nfsrv_rcv(slp);
                                }
                                if (nfsdsock_testbits(slp, SLP_A_DISCONN)) {
                                        nfsrv_zapsock(slp);
                                }
                                error = nfsrv_dorec(slp, nfsd, &nd, &more);
                                getmicrotime(&tv);
                                cur_usec = (u_quad_t)tv.tv_sec * 1000000 +
                                        (u_quad_t)tv.tv_usec;
                                writes_todo = 0;
                                if (error) {
                                        struct nfsrv_descript *nd2;

                                        mutex_enter(&nfsd_lock);
                                        nd2 = LIST_FIRST(&slp->ns_tq);
                                        if (nd2 != NULL &&
                                            nd2->nd_time <= cur_usec) {
                                                error = 0;
                                                cacherep = RC_DOIT;
                                                writes_todo = 1;
                                        }
                                        mutex_exit(&nfsd_lock);
                                }
                                if (error == 0 && more) {
                                        nfsrv_wakenfsd(slp);
                                }
                        }
                } else {
                        error = 0;
                        slp = nfsd->nfsd_slp;
                }
                KASSERT(slp != NULL);
                KASSERT(nfsd->nfsd_slp == slp);
                if (error || (slp->ns_flags & SLP_VALID) == 0) {
                        if (nd) {
                                nfsdreq_free(nd);
                                nd = NULL;
                        }
                        nfsd->nfsd_slp = NULL;
                        nfsrv_slpderef(slp);
                        continue;
                }
                sotype = slp->ns_so->so_type;
                if (nd) {
                        getmicrotime(&nd->nd_starttime);
                        if (nd->nd_nam2)
                                nd->nd_nam = nd->nd_nam2;
                        else
                                nd->nd_nam = slp->ns_nam;

                        /*
                         * Check to see if authorization is needed.
                         */
                        if (nfsd->nfsd_flag & NFSD_NEEDAUTH) {
                                nfsd->nfsd_flag &= ~NFSD_NEEDAUTH;
                                nsd->nsd_haddr = mtod(nd->nd_nam,
                                    struct sockaddr_in *)->sin_addr.s_addr;
                                nsd->nsd_authlen = nfsd->nfsd_authlen;
                                nsd->nsd_verflen = nfsd->nfsd_verflen;
                                if (!copyout(nfsd->nfsd_authstr,
                                    nsd->nsd_authstr, nfsd->nfsd_authlen) &&
                                    !copyout(nfsd->nfsd_verfstr,
                                    nsd->nsd_verfstr, nfsd->nfsd_verflen) &&
                                    !ops->nsd_out(argp, nsd)) {
                                        return (ENEEDAUTH);
                                }
                                cacherep = RC_DROPIT;
                        } else
                                cacherep = nfsrv_getcache(nd, slp, &mreq);

                        if (nfsd->nfsd_flag & NFSD_AUTHFAIL) {
                                nfsd->nfsd_flag &= ~NFSD_AUTHFAIL;
                                nd->nd_procnum = NFSPROC_NOOP;
                                nd->nd_repstat =
                                    (NFSERR_AUTHERR | AUTH_TOOWEAK);
                                cacherep = RC_DOIT;
                        }
                }

                /*
                 * Loop to get all the write rpc relies that have been
                 * gathered together.
                 */
                do {
                        switch (cacherep) {
                        case RC_DOIT:
                                mreq = NULL;
                                netexport_rdlock();
                                if (writes_todo || nd == NULL ||
                                     (!(nd->nd_flag & ND_NFSV3) &&
                                     nd->nd_procnum == NFSPROC_WRITE &&
                                     nfsrvw_procrastinate > 0))
                                        error = nfsrv_writegather(&nd, slp,
                                            l, &mreq);
                                else
                                        error =
                                            (*(nfsrv3_procs[nd->nd_procnum]))
                                            (nd, slp, l, &mreq);
                                netexport_rdunlock();
                                if (mreq == NULL) {
                                        if (nd != NULL) {
                                                if (nd->nd_nam2)
                                                        m_free(nd->nd_nam2);
                                        }
                                        break;
                                }
                                if (error) {
                                        nfsstats.srv_errs++;
                                        if (nd) {
                                                nfsrv_updatecache(nd, false,
                                                    mreq);
                                                m_freem(nd->nd_nam2);
                                        }
                                        break;
                                }
                                if (nd) {
                                        nfsstats.srvrpccnt[nd->nd_procnum]++;
                                        nfsrv_updatecache(nd, true, mreq);
                                        nd->nd_mrep = NULL;
                                }
                                /* FALLTHROUGH */
                        case RC_REPLY:
                                m = mreq;
                                siz = 0;
                                while (m) {
                                        siz += m->m_len;
                                        m = m->m_next;
                                }
                                if (siz <= 0 || siz > NFS_MAXPACKET) {
                                        printf("mbuf siz=%d\n",siz);
                                        panic("Bad nfs svc reply");
                                }
                                m = mreq;
                                m->m_pkthdr.len = siz;
                                m_reset_rcvif(m);
                                /*
                                 * For stream protocols, prepend a Sun RPC
                                 * Record Mark.
                                 */
                                if (sotype == SOCK_STREAM) {
                                        M_PREPEND(m, NFSX_UNSIGNED, M_WAIT);
                                        *mtod(m, u_int32_t *) =
                                            htonl(0x80000000 | siz);
                                }
                                if (nd) {
                                        nd->nd_mreq = m;
                                        if (nfsrtton) {
                                                nfsd_rt(slp->ns_so->so_type, nd,
                                                    cacherep);
                                        }
                                        error = nfsdsock_sendreply(slp, nd);
                                        nd = NULL;
                                }
                                if (error == EPIPE)
                                        nfsrv_zapsock(slp);
                                if (error == EINTR || error == ERESTART) {
                                        nfsd->nfsd_slp = NULL;
                                        nfsrv_slpderef(slp);
                                        goto done;
                                }
                                break;
                        case RC_DROPIT:
                                if (nd) {
                                        if (nfsrtton)
                                                nfsd_rt(sotype, nd, cacherep);
                                        m_freem(nd->nd_mrep);
                                        m_freem(nd->nd_nam2);
                                }
                                break;
                        }
                        if (nd) {
                                nfsdreq_free(nd);
                                nd = NULL;
                        }

                        /*
                         * Check to see if there are outstanding writes that
                         * need to be serviced.
                         */
                        getmicrotime(&tv);
                        cur_usec = (u_quad_t)tv.tv_sec * 1000000 +
                            (u_quad_t)tv.tv_usec;
                        mutex_enter(&nfsd_lock);
                        if (LIST_FIRST(&slp->ns_tq) &&
                            LIST_FIRST(&slp->ns_tq)->nd_time <= cur_usec) {
                                cacherep = RC_DOIT;
                                writes_todo = 1;
                        } else
                                writes_todo = 0;
                        mutex_exit(&nfsd_lock);
                } while (writes_todo);
                if (nfsrv_dorec(slp, nfsd, &nd, &dummy)) {
                        nfsd->nfsd_slp = NULL;
                        nfsrv_slpderef(slp);
                }
        }
done:
        mutex_enter(&nfsd_lock);
        nfsd_toss_cookie(nfsd);
        doreinit = --nfs_numnfsd == 0;
        if (doreinit)
                nfssvc_sockhead_flag |= SLP_INIT;
        mutex_exit(&nfsd_lock);
        cv_destroy(&nfsd->nfsd_cv);
        kmem_free(nfsd, sizeof(*nfsd));
        KASSERT(nsd->nsd_nfsd != (struct nfsd *)(uintptr_t)0);
        nsd->nsd_nfsd = (struct nfsd *)(uintptr_t)0;
        if (doreinit)
                nfsrv_init(true);       /* Reinitialize everything */
        return (error);
}

/*
 * Shut down a socket associated with an nfssvc_sock structure.
 * Should be called with the send lock set, if required.
 * The trick here is to increment the sref at the start, so that the nfsds
 * will stop using it and clear ns_flag at the end so that it will not be
 * reassigned during cleanup.
 *
 * called at splsoftnet.
 */
void
nfsrv_zapsock(struct nfssvc_sock *slp)
{
        struct nfsuid *nuidp, *nnuidp;
        struct nfsrv_descript *nwp;
        struct socket *so;
        struct mbuf *m;

        if (nfsdsock_drain(slp)) {
                return;
        }
        mutex_enter(&nfsd_lock);
        if (slp->ns_gflags & SLP_G_DOREC) {
                TAILQ_REMOVE(&nfssvc_sockpending, slp, ns_pending);
                slp->ns_gflags &= ~SLP_G_DOREC;
        }
        mutex_exit(&nfsd_lock);

        so = slp->ns_so;
        KASSERT(so != NULL);
        solock(so);
        so->so_upcall = NULL;
        so->so_upcallarg = NULL;
        so->so_rcv.sb_flags &= ~SB_UPCALL;
        soshutdown(so, SHUT_RDWR);
        sounlock(so);

        m_freem(slp->ns_raw);
        m_freem(slp->ns_frag);
        m = slp->ns_rec;
        while (m != NULL) {
                struct mbuf *n;

                n = m->m_nextpkt;
                m_freem(m);
                m = n;
        }
        for (nuidp = TAILQ_FIRST(&slp->ns_uidlruhead); nuidp != 0;
            nuidp = nnuidp) {
                nnuidp = TAILQ_NEXT(nuidp, nu_lru);
                LIST_REMOVE(nuidp, nu_hash);
                TAILQ_REMOVE(&slp->ns_uidlruhead, nuidp, nu_lru);
                if (nuidp->nu_flag & NU_NAM)
                        m_freem(nuidp->nu_nam);
                kmem_free(nuidp, sizeof(*nuidp));
        }
        mutex_enter(&nfsd_lock);
        while ((nwp = LIST_FIRST(&slp->ns_tq)) != NULL) {
                LIST_REMOVE(nwp, nd_tq);
                mutex_exit(&nfsd_lock);
                nfsdreq_free(nwp);
                mutex_enter(&nfsd_lock);
        }
        mutex_exit(&nfsd_lock);
}

/*
 * Derefence a server socket structure. If it has no more references and
 * is no longer valid, you can throw it away.
 */
void
nfsrv_slpderef(struct nfssvc_sock *slp)
{
        uint32_t ref;

        mutex_enter(&nfsd_lock);
        KASSERT(slp->ns_sref > 0);
        ref = --slp->ns_sref;
        if (ref == 0 && (slp->ns_flags & SLP_VALID) == 0) {
                file_t *fp;

                KASSERT((slp->ns_gflags & SLP_G_DOREC) == 0);
                TAILQ_REMOVE(&nfssvc_sockhead, slp, ns_chain);
                mutex_exit(&nfsd_lock);

                fp = slp->ns_fp;
                if (fp != NULL) {
                        slp->ns_fp = NULL;
                        KASSERT(fp != NULL);
                        KASSERT(fp->f_socket == slp->ns_so);
                        KASSERT(fp->f_count > 0);
                        closef(fp);
                        slp->ns_so = NULL;
                }
                
                if (slp->ns_nam)
                        m_free(slp->ns_nam);
                nfsrv_sockfree(slp);
        } else
                mutex_exit(&nfsd_lock);
}

/*
 * Initialize the data structures for the server.
 * Handshake with any new nfsds starting up to avoid any chance of
 * corruption.
 */
void
nfsrv_init(int terminating)
{
        struct nfssvc_sock *slp;

        if (!terminating) {
                mutex_init(&nfsd_lock, MUTEX_DRIVER, IPL_SOFTNET);
                cv_init(&nfsd_initcv, "nfsdinit");
        }

        mutex_enter(&nfsd_lock);
        if (!terminating && (nfssvc_sockhead_flag & SLP_INIT) != 0)
                panic("nfsd init");
        nfssvc_sockhead_flag |= SLP_INIT;

        if (terminating) {
                KASSERT(SLIST_EMPTY(&nfsd_idle_head));
                KASSERT(RB_TREE_MIN(&nfsd_tree) == NULL);
                while ((slp = TAILQ_FIRST(&nfssvc_sockhead)) != NULL) {
                        mutex_exit(&nfsd_lock);
                        KASSERT(slp->ns_sref == 0);
                        slp->ns_sref++;
                        nfsrv_zapsock(slp);
                        nfsrv_slpderef(slp);
                        mutex_enter(&nfsd_lock);
                }
                KASSERT(TAILQ_EMPTY(&nfssvc_sockpending));
                mutex_exit(&nfsd_lock);
                nfsrv_cleancache();     /* And clear out server cache */
        } else {
                mutex_exit(&nfsd_lock);
                nfs_pub.np_valid = 0;
        }

        TAILQ_INIT(&nfssvc_sockhead);
        TAILQ_INIT(&nfssvc_sockpending);

        rb_tree_init(&nfsd_tree, &nfsd_tree_ops);
        SLIST_INIT(&nfsd_idle_head);
        nfsd_head_flag &= ~NFSD_CHECKSLP;

        nfs_udpsock = nfsrv_sockalloc();
        nfs_udp6sock = nfsrv_sockalloc();

        mutex_enter(&nfsd_lock);
        nfssvc_sockhead_flag &= ~SLP_INIT;
        cv_broadcast(&nfsd_initcv);
        mutex_exit(&nfsd_lock);
}

void
nfsrv_fini(void)
{

        nfsrv_init(true);
        cv_destroy(&nfsd_initcv);
        mutex_destroy(&nfsd_lock);
}       

/*
 * Add entries to the server monitor log.
 */
static void
nfsd_rt(int sotype, struct nfsrv_descript *nd, int cacherep)
{
        struct timeval tv;
        struct drt *rt;

        rt = &nfsdrt.drt[nfsdrt.pos];
        if (cacherep == RC_DOIT)
                rt->flag = 0;
        else if (cacherep == RC_REPLY)
                rt->flag = DRT_CACHEREPLY;
        else
                rt->flag = DRT_CACHEDROP;
        if (sotype == SOCK_STREAM)
                rt->flag |= DRT_TCP;
        if (nd->nd_flag & ND_NFSV3)
                rt->flag |= DRT_NFSV3;
        rt->proc = nd->nd_procnum;
        if (mtod(nd->nd_nam, struct sockaddr *)->sa_family == AF_INET)
            rt->ipadr = mtod(nd->nd_nam, struct sockaddr_in *)->sin_addr.s_addr;
        else
            rt->ipadr = INADDR_ANY;
        getmicrotime(&tv);
        rt->resptime = ((tv.tv_sec - nd->nd_starttime.tv_sec) * 1000000) +
                (tv.tv_usec - nd->nd_starttime.tv_usec);
        rt->tstamp = tv;
        nfsdrt.pos = (nfsdrt.pos + 1) % NFSRTTLOGSIZ;
}