/*      $NetBSD: nlm_prot_impl.c,v 1.5 2023/04/28 22:31:38 andvar Exp $ */
/*-
* Copyright (c) 2008 Isilon Inc http://www.isilon.com/
* Authors: Doug Rabson <[email protected]>
* Developed with Red Inc: Alfred Perlstein <[email protected]>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/

#ifdef _KERNEL_OPT
#include "opt_inet6.h"
#endif

#include <sys/cdefs.h>
/* __FBSDID("FreeBSD: head/sys/nlm/nlm_prot_impl.c 302216 2016-06-26 20:08:42Z kib "); */
__RCSID("$NetBSD: nlm_prot_impl.c,v 1.5 2023/04/28 22:31:38 andvar Exp $");

#include <sys/param.h>
#include <sys/fail.h>
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lockf.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/syslog.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/taskqueue.h>
#include <sys/unistd.h>
#include <sys/vnode.h>

#if 0
#if __FreeBSD_version >= 700000
#include <sys/priv.h>
#endif
#endif

#include <fs/nfs/common/nfsproto.h>
#include <fs/nfs/common/nfs_lock.h>

#include <fs/nfs/nlm/nlm_prot.h>
#include <fs/nfs/nlm/sm_inter.h>
#include <fs/nfs/nlm/nlm.h>

#include <rpc/rpc_com.h>
#include <rpc/rpcb_prot.h>

MALLOC_DEFINE(M_NLM, "NLM", "Network Lock Manager");

/*
* If a host is inactive (and holds no locks) for this amount of
* seconds, we consider it idle and stop tracking it.
*/
#define NLM_IDLE_TIMEOUT        30

/*
* We check the host list for idle every few seconds.
*/
#define NLM_IDLE_PERIOD         5

/*
* We only look for GRANTED_RES messages for a little while.
*/
#define NLM_EXPIRE_TIMEOUT      10

/*
* Support for sysctl vfs.nlm.sysid
*/
static SYSCTL_NODE(_vfs, OID_AUTO, nlm, CTLFLAG_RW, NULL,
   "Network Lock Manager");
static SYSCTL_NODE(_vfs_nlm, OID_AUTO, sysid, CTLFLAG_RW, NULL, "");

/*
* Syscall hooks
*/
static int nlm_syscall_offset = SYS_nlm_syscall;
static struct sysent nlm_syscall_prev_sysent;
#if __FreeBSD_version < 700000
static struct sysent nlm_syscall_sysent = {
       (sizeof(struct nlm_syscall_args) / sizeof(register_t)) | SYF_MPSAFE,
       (sy_call_t *) nlm_syscall
};
#else
MAKE_SYSENT(nlm_syscall);
#endif
static bool_t nlm_syscall_registered = FALSE;

/*
* Debug level passed in from userland. We also support a sysctl hook
* so that it can be changed on a live system.
*/
static int nlm_debug_level;
SYSCTL_INT(_debug, OID_AUTO, nlm_debug, CTLFLAG_RW, &nlm_debug_level, 0, "");

#define NLM_DEBUG(_level, args...)                      \
       do {                                            \
               if (nlm_debug_level >= (_level))        \
                       log(LOG_DEBUG, args);           \
       } while(0)
#define NLM_ERR(args...)                        \
       do {                                    \
               log(LOG_ERR, args);             \
       } while(0)

/*
* Grace period handling. The value of nlm_grace_threshold is the
* value of time_uptime after which we are serving requests normally.
*/
static time_t nlm_grace_threshold;

/*
* We check for idle hosts if time_uptime is greater than
* nlm_next_idle_check,
*/
static time_t nlm_next_idle_check;

/*
* A flag to indicate the server is already running.
*/
static int nlm_is_running;

/*
* A socket to use for RPC - shared by all IPv4 RPC clients.
*/
static struct socket *nlm_socket;

#ifdef INET6

/*
* A socket to use for RPC - shared by all IPv6 RPC clients.
*/
static struct socket *nlm_socket6;

#endif

/*
* An RPC client handle that can be used to communicate with the local
* NSM.
*/
static CLIENT *nlm_nsm;

/*
* An AUTH handle for the server's creds.
*/
static AUTH *nlm_auth;

/*
* A zero timeval for sending async RPC messages.
*/
struct timeval nlm_zero_tv = { 0, 0 };

/*
* The local NSM state number
*/
int nlm_nsm_state;


/*
* A lock to protect the host list and waiting lock list.
*/
static struct mtx nlm_global_lock;

/*
* Locks:
* (l)          locked by nh_lock
* (s)          only accessed via server RPC which is single threaded
* (g)          locked by nlm_global_lock
* (c)          const until freeing
* (a)          modified using atomic ops
*/

/*
* A pending client-side lock request, stored on the nlm_waiting_locks
* list.
*/
struct nlm_waiting_lock {
       TAILQ_ENTRY(nlm_waiting_lock) nw_link; /* (g) */
       bool_t          nw_waiting;            /* (g) */
       nlm4_lock       nw_lock;               /* (c) */
       union nfsfh     nw_fh;                 /* (c) */
       struct vnode    *nw_vp;                /* (c) */
};
TAILQ_HEAD(nlm_waiting_lock_list, nlm_waiting_lock);

struct nlm_waiting_lock_list nlm_waiting_locks; /* (g) */

/*
* A pending server-side asynchronous lock request, stored on the
* nh_pending list of the NLM host.
*/
struct nlm_async_lock {
       TAILQ_ENTRY(nlm_async_lock) af_link; /* (l) host's list of locks */
       struct task     af_task;        /* (c) async callback details */
       void            *af_cookie;     /* (l) lock manager cancel token */
       struct vnode    *af_vp;         /* (l) vnode to lock */
       struct flock    af_fl;          /* (c) lock details */
       struct nlm_host *af_host;       /* (c) host which is locking */
       CLIENT          *af_rpc;        /* (c) rpc client to send message */
       nlm4_testargs   af_granted;     /* (c) notification details */
       time_t          af_expiretime;  /* (c) notification time */
};
TAILQ_HEAD(nlm_async_lock_list, nlm_async_lock);

/*
* NLM host.
*/
enum nlm_host_state {
       NLM_UNMONITORED,
       NLM_MONITORED,
       NLM_MONITOR_FAILED,
       NLM_RECOVERING
};

struct nlm_rpc {
       CLIENT          *nr_client;    /* (l) RPC client handle */
       time_t          nr_create_time; /* (l) when client was created */
};

struct nlm_host {
       struct mtx      nh_lock;
       volatile u_int  nh_refs;       /* (a) reference count */
       TAILQ_ENTRY(nlm_host) nh_link; /* (g) global list of hosts */
       char            nh_caller_name[MAXNAMELEN]; /* (c) printable name of host */
       uint32_t        nh_sysid;        /* (c) our allocated system ID */
       char            nh_sysid_string[10]; /* (c) string rep. of sysid */
       struct sockaddr_storage nh_addr; /* (s) remote address of host */
       struct nlm_rpc  nh_srvrpc;       /* (l) RPC for server replies */
       struct nlm_rpc  nh_clntrpc;      /* (l) RPC for client requests */
       rpcvers_t       nh_vers;         /* (s) NLM version of host */
       int             nh_state;        /* (s) last seen NSM state of host */
       enum nlm_host_state nh_monstate; /* (l) local NSM monitoring state */
       time_t          nh_idle_timeout; /* (s) Time at which host is idle */
       struct sysctl_ctx_list nh_sysctl; /* (c) vfs.nlm.sysid nodes */
       uint32_t        nh_grantcookie;  /* (l) grant cookie counter */
       struct nlm_async_lock_list nh_pending; /* (l) pending async locks */
       struct nlm_async_lock_list nh_granted; /* (l) granted locks */
       struct nlm_async_lock_list nh_finished; /* (l) finished async locks */
};
TAILQ_HEAD(nlm_host_list, nlm_host);

static struct nlm_host_list nlm_hosts; /* (g) */
static uint32_t nlm_next_sysid = 1;    /* (g) */

static void     nlm_host_unmonitor(struct nlm_host *);

struct nlm_grantcookie {
       uint32_t        ng_sysid;
       uint32_t        ng_cookie;
};

static inline uint32_t
ng_sysid(struct netobj *src)
{

       return ((struct nlm_grantcookie *)src->n_bytes)->ng_sysid;
}

static inline uint32_t
ng_cookie(struct netobj *src)
{

       return ((struct nlm_grantcookie *)src->n_bytes)->ng_cookie;
}

/**********************************************************************/

/*
* Initialise NLM globals.
*/
static void
nlm_init(void *dummy)
{
       int error;

       mtx_init(&nlm_global_lock, "nlm_global_lock", NULL, MTX_DEF);
       TAILQ_INIT(&nlm_waiting_locks);
       TAILQ_INIT(&nlm_hosts);

       error = syscall_register(&nlm_syscall_offset, &nlm_syscall_sysent,
           &nlm_syscall_prev_sysent, SY_THR_STATIC_KLD);
       if (error)
               NLM_ERR("Can't register NLM syscall\n");
       else
               nlm_syscall_registered = TRUE;
}
SYSINIT(nlm_init, SI_SUB_LOCK, SI_ORDER_FIRST, nlm_init, NULL);

static void
nlm_uninit(void *dummy)
{

       if (nlm_syscall_registered)
               syscall_deregister(&nlm_syscall_offset,
                   &nlm_syscall_prev_sysent);
}
SYSUNINIT(nlm_uninit, SI_SUB_LOCK, SI_ORDER_FIRST, nlm_uninit, NULL);

/*
* Create a netobj from an arbitrary source.
*/
void
nlm_make_netobj(struct netobj *dst, caddr_t src, size_t srcsize,
   struct malloc_type *type)
{

       dst->n_len = srcsize;
       dst->n_bytes = malloc(srcsize, type, M_WAITOK);
       memcpy(dst->n_bytes, src, srcsize);
}

/*
* Copy a struct netobj.
*/
void
nlm_copy_netobj(struct netobj *dst, struct netobj *src,
   struct malloc_type *type)
{

       nlm_make_netobj(dst, src->n_bytes, src->n_len, type);
}


/*
* Create an RPC client handle for the given (address,prog,vers)
* triple using UDP.
*/
static CLIENT *
nlm_get_rpc(struct sockaddr *sa, rpcprog_t prog, rpcvers_t vers)
{
       char *wchan = "nlmrcv";
       const char* protofmly;
       struct sockaddr_storage ss;
       struct socket *so;
       CLIENT *rpcb;
       struct timeval timo;
       RPCB parms;
       char *uaddr;
       enum clnt_stat stat = RPC_SUCCESS;
       int rpcvers = RPCBVERS4;
       bool_t do_tcp = FALSE;
       bool_t tryagain = FALSE;
       struct portmap mapping;
       u_short port = 0;

       /*
        * First we need to contact the remote RPCBIND service to find
        * the right port.
        */
       memcpy(&ss, sa, sa->sa_len);
       switch (ss.ss_family) {
       case AF_INET:
               ((struct sockaddr_in *)&ss)->sin_port = htons(111);
               protofmly = "inet";
               so = nlm_socket;
               break;

#ifdef INET6
       case AF_INET6:
               ((struct sockaddr_in6 *)&ss)->sin6_port = htons(111);
               protofmly = "inet6";
               so = nlm_socket6;
               break;
#endif

       default:
               /*
                * Unsupported address family - fail.
                */
               return (NULL);
       }

       rpcb = clnt_dg_create(so, (struct sockaddr *)&ss,
           RPCBPROG, rpcvers, 0, 0);
       if (!rpcb)
               return (NULL);

try_tcp:
       parms.r_prog = prog;
       parms.r_vers = vers;
       if (do_tcp)
               parms.r_netid = "tcp";
       else
               parms.r_netid = "udp";
       parms.r_addr = "";
       parms.r_owner = "";

       /*
        * Use the default timeout.
        */
       timo.tv_sec = 25;
       timo.tv_usec = 0;
again:
       switch (rpcvers) {
       case RPCBVERS4:
       case RPCBVERS:
               /*
                * Try RPCBIND 4 then 3.
                */
               uaddr = NULL;
               stat = CLNT_CALL(rpcb, (rpcprog_t) RPCBPROC_GETADDR,
                   (xdrproc_t) xdr_rpcb, &parms,
                   (xdrproc_t) xdr_wrapstring, &uaddr, timo);
               if (stat == RPC_SUCCESS) {
                       /*
                        * We have a reply from the remote RPCBIND - turn it
                        * into an appropriate address and make a new client
                        * that can talk to the remote NLM.
                        *
                        * XXX fixup IPv6 scope ID.
                        */
                       struct netbuf *a;
                       a = __rpc_uaddr2taddr_af(ss.ss_family, uaddr);
                       if (!a) {
                               tryagain = TRUE;
                       } else {
                               tryagain = FALSE;
                               memcpy(&ss, a->buf, a->len);
                               free(a->buf, M_RPC);
                               free(a, M_RPC);
                               xdr_free((xdrproc_t) xdr_wrapstring, &uaddr);
                       }
               }
               if (tryagain || stat == RPC_PROGVERSMISMATCH) {
                       if (rpcvers == RPCBVERS4)
                               rpcvers = RPCBVERS;
                       else if (rpcvers == RPCBVERS)
                               rpcvers = PMAPVERS;
                       CLNT_CONTROL(rpcb, CLSET_VERS, &rpcvers);
                       goto again;
               }
               break;
       case PMAPVERS:
               /*
                * Try portmap.
                */
               mapping.pm_prog = parms.r_prog;
               mapping.pm_vers = parms.r_vers;
               mapping.pm_prot = do_tcp ? IPPROTO_TCP : IPPROTO_UDP;
               mapping.pm_port = 0;

               stat = CLNT_CALL(rpcb, (rpcprog_t) PMAPPROC_GETPORT,
                   (xdrproc_t) xdr_portmap, &mapping,
                   (xdrproc_t) xdr_u_short, &port, timo);

               if (stat == RPC_SUCCESS) {
                       switch (ss.ss_family) {
                       case AF_INET:
                               ((struct sockaddr_in *)&ss)->sin_port =
                                       htons(port);
                               break;

#ifdef INET6
                       case AF_INET6:
                               ((struct sockaddr_in6 *)&ss)->sin6_port =
                                       htons(port);
                               break;
#endif
                       }
               }
               break;
       default:
               panic("invalid rpcvers %d", rpcvers);
       }
       /*
        * We may have a positive response from the portmapper, but the NLM
        * service was not found. Make sure we received a valid port.
        */
       switch (ss.ss_family) {
       case AF_INET:
               port = ((struct sockaddr_in *)&ss)->sin_port;
               break;
#ifdef INET6
       case AF_INET6:
               port = ((struct sockaddr_in6 *)&ss)->sin6_port;
               break;
#endif
       }
       if (stat != RPC_SUCCESS || !port) {
               /*
                * If we were able to talk to rpcbind or portmap, but the udp
                * variant wasn't available, ask about tcp.
                *
                * XXX - We could also check for a TCP portmapper, but
                * if the host is running a portmapper at all, we should be able
                * to hail it over UDP.
                */
               if (stat == RPC_SUCCESS && !do_tcp) {
                       do_tcp = TRUE;
                       goto try_tcp;
               }

               /* Otherwise, bad news. */
               NLM_ERR("NLM: failed to contact remote rpcbind, "
                   "stat = %d, port = %d\n", (int) stat, port);
               CLNT_DESTROY(rpcb);
               return (NULL);
       }

       if (do_tcp) {
               /*
                * Destroy the UDP client we used to speak to rpcbind and
                * recreate as a TCP client.
                */
               struct netconfig *nconf = NULL;

               CLNT_DESTROY(rpcb);

               switch (ss.ss_family) {
               case AF_INET:
                       nconf = getnetconfigent("tcp");
                       break;
#ifdef INET6
               case AF_INET6:
                       nconf = getnetconfigent("tcp6");
                       break;
#endif
               }

               rpcb = clnt_reconnect_create(nconf, (struct sockaddr *)&ss,
                   prog, vers, 0, 0);
               CLNT_CONTROL(rpcb, CLSET_WAITCHAN, wchan);
               rpcb->cl_auth = nlm_auth;

       } else {
               /*
                * Re-use the client we used to speak to rpcbind.
                */
               CLNT_CONTROL(rpcb, CLSET_SVC_ADDR, &ss);
               CLNT_CONTROL(rpcb, CLSET_PROG, &prog);
               CLNT_CONTROL(rpcb, CLSET_VERS, &vers);
               CLNT_CONTROL(rpcb, CLSET_WAITCHAN, wchan);
               rpcb->cl_auth = nlm_auth;
       }

       return (rpcb);
}

/*
* This async callback after when an async lock request has been
* granted. We notify the host which initiated the request.
*/
static void
nlm_lock_callback(void *arg, int pending)
{
       struct nlm_async_lock *af = (struct nlm_async_lock *) arg;
       struct rpc_callextra ext;

       NLM_DEBUG(2, "NLM: async lock %p for %s (sysid %d) granted,"
           " cookie %d:%d\n", af, af->af_host->nh_caller_name,
           af->af_host->nh_sysid, ng_sysid(&af->af_granted.cookie),
           ng_cookie(&af->af_granted.cookie));

       /*
        * Send the results back to the host.
        *
        * Note: there is a possible race here with nlm_host_notify
        * destroying the RPC client. To avoid problems, the first
        * thing nlm_host_notify does is to cancel pending async lock
        * requests.
        */
       memset(&ext, 0, sizeof(ext));
       ext.rc_auth = nlm_auth;
       if (af->af_host->nh_vers == NLM_VERS4) {
               nlm4_granted_msg_4(&af->af_granted,
                   NULL, af->af_rpc, &ext, nlm_zero_tv);
       } else {
               /*
                * Back-convert to legacy protocol
                */
               nlm_testargs granted;
               granted.cookie = af->af_granted.cookie;
               granted.exclusive = af->af_granted.exclusive;
               granted.alock.caller_name =
                       af->af_granted.alock.caller_name;
               granted.alock.fh = af->af_granted.alock.fh;
               granted.alock.oh = af->af_granted.alock.oh;
               granted.alock.svid = af->af_granted.alock.svid;
               granted.alock.l_offset =
                       af->af_granted.alock.l_offset;
               granted.alock.l_len =
                       af->af_granted.alock.l_len;

               nlm_granted_msg_1(&granted,
                   NULL, af->af_rpc, &ext, nlm_zero_tv);
       }

       /*
        * Move this entry to the nh_granted list.
        */
       af->af_expiretime = time_uptime + NLM_EXPIRE_TIMEOUT;
       mtx_lock(&af->af_host->nh_lock);
       TAILQ_REMOVE(&af->af_host->nh_pending, af, af_link);
       TAILQ_INSERT_TAIL(&af->af_host->nh_granted, af, af_link);
       mtx_unlock(&af->af_host->nh_lock);
}

/*
* Free an async lock request. The request must have been removed from
* any list.
*/
static void
nlm_free_async_lock(struct nlm_async_lock *af)
{
       /*
        * Free an async lock.
        */
       if (af->af_rpc)
               CLNT_RELEASE(af->af_rpc);
       xdr_free((xdrproc_t) xdr_nlm4_testargs, &af->af_granted);
       if (af->af_vp)
               vrele(af->af_vp);
       free(af, M_NLM);
}

/*
* Cancel our async request - this must be called with
* af->nh_host->nh_lock held. This is slightly complicated by a
* potential race with our own callback. If we fail to cancel the
* lock, it must already have been granted - we make sure our async
* task has completed by calling taskqueue_drain in this case.
*/
static int
nlm_cancel_async_lock(struct nlm_async_lock *af)
{
       struct nlm_host *host = af->af_host;
       int error;

       mtx_assert(&host->nh_lock, MA_OWNED);

       mtx_unlock(&host->nh_lock);

       error = VOP_ADVLOCKASYNC(af->af_vp, NULL, F_CANCEL, &af->af_fl,
           F_REMOTE, NULL, &af->af_cookie);

       if (error) {
               /*
                * We failed to cancel - make sure our callback has
                * completed before we continue.
                */
               taskqueue_drain(taskqueue_thread, &af->af_task);
       }

       mtx_lock(&host->nh_lock);

       if (!error) {
               NLM_DEBUG(2, "NLM: async lock %p for %s (sysid %d) "
                   "cancelled\n", af, host->nh_caller_name, host->nh_sysid);

               /*
                * Remove from the nh_pending list and free now that
                * we are safe from the callback.
                */
               TAILQ_REMOVE(&host->nh_pending, af, af_link);
               mtx_unlock(&host->nh_lock);
               nlm_free_async_lock(af);
               mtx_lock(&host->nh_lock);
       }

       return (error);
}

static void
nlm_check_expired_locks(struct nlm_host *host)
{
       struct nlm_async_lock *af;
       time_t uptime = time_uptime;

       mtx_lock(&host->nh_lock);
       while ((af = TAILQ_FIRST(&host->nh_granted)) != NULL
           && uptime >= af->af_expiretime) {
               NLM_DEBUG(2, "NLM: async lock %p for %s (sysid %d) expired,"
                   " cookie %d:%d\n", af, af->af_host->nh_caller_name,
                   af->af_host->nh_sysid, ng_sysid(&af->af_granted.cookie),
                   ng_cookie(&af->af_granted.cookie));
               TAILQ_REMOVE(&host->nh_granted, af, af_link);
               mtx_unlock(&host->nh_lock);
               nlm_free_async_lock(af);
               mtx_lock(&host->nh_lock);
       }
       while ((af = TAILQ_FIRST(&host->nh_finished)) != NULL) {
               TAILQ_REMOVE(&host->nh_finished, af, af_link);
               mtx_unlock(&host->nh_lock);
               nlm_free_async_lock(af);
               mtx_lock(&host->nh_lock);
       }
       mtx_unlock(&host->nh_lock);
}

/*
* Free resources used by a host. This is called after the reference
* count has reached zero so it doesn't need to worry about locks.
*/
static void
nlm_host_destroy(struct nlm_host *host)
{

       mtx_lock(&nlm_global_lock);
       TAILQ_REMOVE(&nlm_hosts, host, nh_link);
       mtx_unlock(&nlm_global_lock);

       if (host->nh_srvrpc.nr_client)
               CLNT_RELEASE(host->nh_srvrpc.nr_client);
       if (host->nh_clntrpc.nr_client)
               CLNT_RELEASE(host->nh_clntrpc.nr_client);
       mtx_destroy(&host->nh_lock);
       sysctl_ctx_free(&host->nh_sysctl);
       free(host, M_NLM);
}

/*
* Thread start callback for client lock recovery
*/
static void
nlm_client_recovery_start(void *arg)
{
       struct nlm_host *host = (struct nlm_host *) arg;

       NLM_DEBUG(1, "NLM: client lock recovery for %s started\n",
           host->nh_caller_name);

       nlm_client_recovery(host);

       NLM_DEBUG(1, "NLM: client lock recovery for %s completed\n",
           host->nh_caller_name);

       host->nh_monstate = NLM_MONITORED;
       nlm_host_release(host);

       kthread_exit();
}

/*
* This is called when we receive a host state change notification. We
* unlock any active locks owned by the host. When rpc.lockd is
* shutting down, this function is called with newstate set to zero
* which allows us to cancel any pending async locks and clear the
* locking state.
*/
static void
nlm_host_notify(struct nlm_host *host, int newstate)
{
       struct nlm_async_lock *af;

       if (newstate) {
               NLM_DEBUG(1, "NLM: host %s (sysid %d) rebooted, new "
                   "state is %d\n", host->nh_caller_name,
                   host->nh_sysid, newstate);
       }

       /*
        * Cancel any pending async locks for this host.
        */
       mtx_lock(&host->nh_lock);
       while ((af = TAILQ_FIRST(&host->nh_pending)) != NULL) {
               /*
                * nlm_cancel_async_lock will remove the entry from
                * nh_pending and free it.
                */
               nlm_cancel_async_lock(af);
       }
       mtx_unlock(&host->nh_lock);
       nlm_check_expired_locks(host);

       /*
        * The host just rebooted - trash its locks.
        */
       lf_clearremotesys(host->nh_sysid);
       host->nh_state = newstate;

       /*
        * If we have any remote locks for this host (i.e. it
        * represents a remote NFS server that our local NFS client
        * has locks for), start a recovery thread.
        */
       if (newstate != 0
           && host->nh_monstate != NLM_RECOVERING
           && lf_countlocks(NLM_SYSID_CLIENT | host->nh_sysid) > 0) {
               struct thread *td;
               host->nh_monstate = NLM_RECOVERING;
               refcount_acquire(&host->nh_refs);
               kthread_add(nlm_client_recovery_start, host, curproc, &td, 0, 0,
                   "NFS lock recovery for %s", host->nh_caller_name);
       }
}

/*
* Sysctl handler to count the number of locks for a sysid.
*/
static int
nlm_host_lock_count_sysctl(SYSCTL_HANDLER_ARGS)
{
       struct nlm_host *host;
       int count;

       host = oidp->oid_arg1;
       count = lf_countlocks(host->nh_sysid);
       return sysctl_handle_int(oidp, &count, 0, req);
}

/*
* Sysctl handler to count the number of client locks for a sysid.
*/
static int
nlm_host_client_lock_count_sysctl(SYSCTL_HANDLER_ARGS)
{
       struct nlm_host *host;
       int count;

       host = oidp->oid_arg1;
       count = lf_countlocks(NLM_SYSID_CLIENT | host->nh_sysid);
       return sysctl_handle_int(oidp, &count, 0, req);
}

/*
* Create a new NLM host.
*/
static struct nlm_host *
nlm_create_host(const char* caller_name)
{
       struct nlm_host *host;
       struct sysctl_oid *oid;

       mtx_assert(&nlm_global_lock, MA_OWNED);

       NLM_DEBUG(1, "NLM: new host %s (sysid %d)\n",
           caller_name, nlm_next_sysid);
       host = malloc(sizeof(struct nlm_host), M_NLM, M_NOWAIT|M_ZERO);
       if (!host)
               return (NULL);
       mtx_init(&host->nh_lock, "nh_lock", NULL, MTX_DEF);
       host->nh_refs = 1;
       strlcpy(host->nh_caller_name, caller_name, MAXNAMELEN);
       host->nh_sysid = nlm_next_sysid++;
       snprintf(host->nh_sysid_string, sizeof(host->nh_sysid_string),
               "%d", host->nh_sysid);
       host->nh_vers = 0;
       host->nh_state = 0;
       host->nh_monstate = NLM_UNMONITORED;
       host->nh_grantcookie = 1;
       TAILQ_INIT(&host->nh_pending);
       TAILQ_INIT(&host->nh_granted);
       TAILQ_INIT(&host->nh_finished);
       TAILQ_INSERT_TAIL(&nlm_hosts, host, nh_link);

       mtx_unlock(&nlm_global_lock);

       sysctl_ctx_init(&host->nh_sysctl);
       oid = SYSCTL_ADD_NODE(&host->nh_sysctl,
           SYSCTL_STATIC_CHILDREN(_vfs_nlm_sysid),
           OID_AUTO, host->nh_sysid_string, CTLFLAG_RD, NULL, "");
       SYSCTL_ADD_STRING(&host->nh_sysctl, SYSCTL_CHILDREN(oid), OID_AUTO,
           "hostname", CTLFLAG_RD, host->nh_caller_name, 0, "");
       SYSCTL_ADD_UINT(&host->nh_sysctl, SYSCTL_CHILDREN(oid), OID_AUTO,
           "version", CTLFLAG_RD, &host->nh_vers, 0, "");
       SYSCTL_ADD_UINT(&host->nh_sysctl, SYSCTL_CHILDREN(oid), OID_AUTO,
           "monitored", CTLFLAG_RD, &host->nh_monstate, 0, "");
       SYSCTL_ADD_PROC(&host->nh_sysctl, SYSCTL_CHILDREN(oid), OID_AUTO,
           "lock_count", CTLTYPE_INT | CTLFLAG_RD, host, 0,
           nlm_host_lock_count_sysctl, "I", "");
       SYSCTL_ADD_PROC(&host->nh_sysctl, SYSCTL_CHILDREN(oid), OID_AUTO,
           "client_lock_count", CTLTYPE_INT | CTLFLAG_RD, host, 0,
           nlm_host_client_lock_count_sysctl, "I", "");

       mtx_lock(&nlm_global_lock);

       return (host);
}

/*
* Acquire the next sysid for remote locks not handled by the NLM.
*/
uint32_t
nlm_acquire_next_sysid(void)
{
       uint32_t next_sysid;

       mtx_lock(&nlm_global_lock);
       next_sysid = nlm_next_sysid++;
       mtx_unlock(&nlm_global_lock);
       return (next_sysid);
}

/*
* Return non-zero if the address parts of the two sockaddrs are the
* same.
*/
static int
nlm_compare_addr(const struct sockaddr *a, const struct sockaddr *b)
{
       const struct sockaddr_in *a4, *b4;
#ifdef INET6
       const struct sockaddr_in6 *a6, *b6;
#endif

       if (a->sa_family != b->sa_family)
               return (FALSE);

       switch (a->sa_family) {
       case AF_INET:
               a4 = (const struct sockaddr_in *) a;
               b4 = (const struct sockaddr_in *) b;
               return !memcmp(&a4->sin_addr, &b4->sin_addr,
                   sizeof(a4->sin_addr));
#ifdef INET6
       case AF_INET6:
               a6 = (const struct sockaddr_in6 *) a;
               b6 = (const struct sockaddr_in6 *) b;
               return !memcmp(&a6->sin6_addr, &b6->sin6_addr,
                   sizeof(a6->sin6_addr));
#endif
       }

       return (0);
}

/*
* Check for idle hosts and stop monitoring them. We could also free
* the host structure here, possibly after a larger timeout but that
* would require some care to avoid races with
* e.g. nlm_host_lock_count_sysctl.
*/
static void
nlm_check_idle(void)
{
       struct nlm_host *host;

       mtx_assert(&nlm_global_lock, MA_OWNED);

       if (time_uptime <= nlm_next_idle_check)
               return;

       nlm_next_idle_check = time_uptime + NLM_IDLE_PERIOD;

       TAILQ_FOREACH(host, &nlm_hosts, nh_link) {
               if (host->nh_monstate == NLM_MONITORED
                   && time_uptime > host->nh_idle_timeout) {
                       mtx_unlock(&nlm_global_lock);
                       if (lf_countlocks(host->nh_sysid) > 0
                           || lf_countlocks(NLM_SYSID_CLIENT
                               + host->nh_sysid)) {
                               host->nh_idle_timeout =
                                       time_uptime + NLM_IDLE_TIMEOUT;
                               mtx_lock(&nlm_global_lock);
                               continue;
                       }
                       nlm_host_unmonitor(host);
                       mtx_lock(&nlm_global_lock);
               }
       }
}

/*
* Search for an existing NLM host that matches the given name
* (typically the caller_name element of an nlm4_lock).  If none is
* found, create a new host. If 'addr' is non-NULL, record the remote
* address of the host so that we can call it back for async
* responses. If 'vers' is greater than zero then record the NLM
* program version to use to communicate with this client.
*/
struct nlm_host *
nlm_find_host_by_name(const char *name, const struct sockaddr *addr,
   rpcvers_t vers)
{
       struct nlm_host *host;

       mtx_lock(&nlm_global_lock);

       /*
        * The remote host is determined by caller_name.
        */
       TAILQ_FOREACH(host, &nlm_hosts, nh_link) {
               if (!strcmp(host->nh_caller_name, name))
                       break;
       }

       if (!host) {
               host = nlm_create_host(name);
               if (!host) {
                       mtx_unlock(&nlm_global_lock);
                       return (NULL);
               }
       }
       refcount_acquire(&host->nh_refs);

       host->nh_idle_timeout = time_uptime + NLM_IDLE_TIMEOUT;

       /*
        * If we have an address for the host, record it so that we
        * can send async replies etc.
        */
       if (addr) {

               KASSERT(addr->sa_len < sizeof(struct sockaddr_storage),
                   ("Strange remote transport address length"));

               /*
                * If we have seen an address before and we currently
                * have an RPC client handle, make sure the address is
                * the same, otherwise discard the client handle.
                */
               if (host->nh_addr.ss_len && host->nh_srvrpc.nr_client) {
                       if (!nlm_compare_addr(
                                   (struct sockaddr *) &host->nh_addr,
                                   addr)
                           || host->nh_vers != vers) {
                               CLIENT *client;
                               mtx_lock(&host->nh_lock);
                               client = host->nh_srvrpc.nr_client;
                               host->nh_srvrpc.nr_client = NULL;
                               mtx_unlock(&host->nh_lock);
                               if (client) {
                                       CLNT_RELEASE(client);
                               }
                       }
               }
               memcpy(&host->nh_addr, addr, addr->sa_len);
               host->nh_vers = vers;
       }

       nlm_check_idle();

       mtx_unlock(&nlm_global_lock);

       return (host);
}

/*
* Search for an existing NLM host that matches the given remote
* address. If none is found, create a new host with the requested
* address and remember 'vers' as the NLM protocol version to use for
* that host.
*/
struct nlm_host *
nlm_find_host_by_addr(const struct sockaddr *addr, int vers)
{
       /*
        * Fake up a name using inet_ntop. This buffer is
        * large enough for an IPv6 address.
        */
       char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"];
       struct nlm_host *host;

       switch (addr->sa_family) {
       case AF_INET:
               inet_ntop(AF_INET,
                   &((const struct sockaddr_in *) addr)->sin_addr,
                   tmp, sizeof tmp);
               break;
#ifdef INET6
       case AF_INET6:
               inet_ntop(AF_INET6,
                   &((const struct sockaddr_in6 *) addr)->sin6_addr,
                   tmp, sizeof tmp);
               break;
#endif
       default:
               strlcpy(tmp, "<unknown>", sizeof(tmp));
       }


       mtx_lock(&nlm_global_lock);

       /*
        * The remote host is determined by caller_name.
        */
       TAILQ_FOREACH(host, &nlm_hosts, nh_link) {
               if (nlm_compare_addr(addr,
                       (const struct sockaddr *) &host->nh_addr))
                       break;
       }

       if (!host) {
               host = nlm_create_host(tmp);
               if (!host) {
                       mtx_unlock(&nlm_global_lock);
                       return (NULL);
               }
               memcpy(&host->nh_addr, addr, addr->sa_len);
               host->nh_vers = vers;
       }
       refcount_acquire(&host->nh_refs);

       host->nh_idle_timeout = time_uptime + NLM_IDLE_TIMEOUT;

       nlm_check_idle();

       mtx_unlock(&nlm_global_lock);

       return (host);
}

/*
* Find the NLM host that matches the value of 'sysid'. If none
* exists, return NULL.
*/
static struct nlm_host *
nlm_find_host_by_sysid(int sysid)
{
       struct nlm_host *host;

       TAILQ_FOREACH(host, &nlm_hosts, nh_link) {
               if (host->nh_sysid == sysid) {
                       refcount_acquire(&host->nh_refs);
                       return (host);
               }
       }

       return (NULL);
}

void nlm_host_release(struct nlm_host *host)
{
       if (refcount_release(&host->nh_refs)) {
               /*
                * Free the host
                */
               nlm_host_destroy(host);
       }
}

/*
* Unregister this NLM host with the local NSM due to idleness.
*/
static void
nlm_host_unmonitor(struct nlm_host *host)
{
       mon_id smmonid;
       sm_stat_res smstat;
       struct timeval timo;
       enum clnt_stat stat;

       NLM_DEBUG(1, "NLM: unmonitoring %s (sysid %d)\n",
           host->nh_caller_name, host->nh_sysid);

       /*
        * We put our assigned system ID value in the priv field to
        * make it simpler to find the host if we are notified of a
        * host restart.
        */
       smmonid.mon_name = host->nh_caller_name;
       smmonid.my_id.my_name = "localhost";
       smmonid.my_id.my_prog = NLM_PROG;
       smmonid.my_id.my_vers = NLM_SM;
       smmonid.my_id.my_proc = NLM_SM_NOTIFY;

       timo.tv_sec = 25;
       timo.tv_usec = 0;
       stat = CLNT_CALL(nlm_nsm, SM_UNMON,
           (xdrproc_t) xdr_mon, &smmonid,
           (xdrproc_t) xdr_sm_stat, &smstat, timo);

       if (stat != RPC_SUCCESS) {
               NLM_ERR("Failed to contact local NSM - rpc error %d\n", stat);
               return;
       }
       if (smstat.res_stat == stat_fail) {
               NLM_ERR("Local NSM refuses to unmonitor %s\n",
                   host->nh_caller_name);
               return;
       }

       host->nh_monstate = NLM_UNMONITORED;
}

/*
* Register this NLM host with the local NSM so that we can be
* notified if it reboots.
*/
void
nlm_host_monitor(struct nlm_host *host, int state)
{
       mon smmon;
       sm_stat_res smstat;
       struct timeval timo;
       enum clnt_stat stat;

       if (state && !host->nh_state) {
               /*
                * This is the first time we have seen an NSM state
                * value for this host. We record it here to help
                * detect host reboots.
                */
               host->nh_state = state;
               NLM_DEBUG(1, "NLM: host %s (sysid %d) has NSM state %d\n",
                   host->nh_caller_name, host->nh_sysid, state);
       }

       mtx_lock(&host->nh_lock);
       if (host->nh_monstate != NLM_UNMONITORED) {
               mtx_unlock(&host->nh_lock);
               return;
       }
       host->nh_monstate = NLM_MONITORED;
       mtx_unlock(&host->nh_lock);

       NLM_DEBUG(1, "NLM: monitoring %s (sysid %d)\n",
           host->nh_caller_name, host->nh_sysid);

       /*
        * We put our assigned system ID value in the priv field to
        * make it simpler to find the host if we are notified of a
        * host restart.
        */
       smmon.mon_id.mon_name = host->nh_caller_name;
       smmon.mon_id.my_id.my_name = "localhost";
       smmon.mon_id.my_id.my_prog = NLM_PROG;
       smmon.mon_id.my_id.my_vers = NLM_SM;
       smmon.mon_id.my_id.my_proc = NLM_SM_NOTIFY;
       memcpy(smmon.priv, &host->nh_sysid, sizeof(host->nh_sysid));

       timo.tv_sec = 25;
       timo.tv_usec = 0;
       stat = CLNT_CALL(nlm_nsm, SM_MON,
           (xdrproc_t) xdr_mon, &smmon,
           (xdrproc_t) xdr_sm_stat, &smstat, timo);

       if (stat != RPC_SUCCESS) {
               NLM_ERR("Failed to contact local NSM - rpc error %d\n", stat);
               return;
       }
       if (smstat.res_stat == stat_fail) {
               NLM_ERR("Local NSM refuses to monitor %s\n",
                   host->nh_caller_name);
               mtx_lock(&host->nh_lock);
               host->nh_monstate = NLM_MONITOR_FAILED;
               mtx_unlock(&host->nh_lock);
               return;
       }

       host->nh_monstate = NLM_MONITORED;
}

/*
* Return an RPC client handle that can be used to talk to the NLM
* running on the given host.
*/
CLIENT *
nlm_host_get_rpc(struct nlm_host *host, bool_t isserver)
{
       struct nlm_rpc *rpc;
       CLIENT *client;

       mtx_lock(&host->nh_lock);

       if (isserver)
               rpc = &host->nh_srvrpc;
       else
               rpc = &host->nh_clntrpc;

       /*
        * We can't hold onto RPC handles for too long - the async
        * call/reply protocol used by some NLM clients makes it hard
        * to tell when they change port numbers (e.g. after a
        * reboot). Note that if a client reboots while it isn't
        * holding any locks, it won't bother to notify us. We
        * expire the RPC handles after two minutes.
        */
       if (rpc->nr_client && time_uptime > rpc->nr_create_time + 2*60) {
               client = rpc->nr_client;
               rpc->nr_client = NULL;
               mtx_unlock(&host->nh_lock);
               CLNT_RELEASE(client);
               mtx_lock(&host->nh_lock);
       }

       if (!rpc->nr_client) {
               mtx_unlock(&host->nh_lock);
               client = nlm_get_rpc((struct sockaddr *)&host->nh_addr,
                   NLM_PROG, host->nh_vers);
               mtx_lock(&host->nh_lock);

               if (client) {
                       if (rpc->nr_client) {
                               mtx_unlock(&host->nh_lock);
                               CLNT_DESTROY(client);
                               mtx_lock(&host->nh_lock);
                       } else {
                               rpc->nr_client = client;
                               rpc->nr_create_time = time_uptime;
                       }
               }
       }

       client = rpc->nr_client;
       if (client)
               CLNT_ACQUIRE(client);
       mtx_unlock(&host->nh_lock);

       return (client);

}

int nlm_host_get_sysid(struct nlm_host *host)
{

       return (host->nh_sysid);
}

int
nlm_host_get_state(struct nlm_host *host)
{

       return (host->nh_state);
}

void *
nlm_register_wait_lock(struct nlm4_lock *lock, struct vnode *vp)
{
       struct nlm_waiting_lock *nw;

       nw = malloc(sizeof(struct nlm_waiting_lock), M_NLM, M_WAITOK);
       nw->nw_lock = *lock;
       memcpy(&nw->nw_fh.fh_bytes, nw->nw_lock.fh.n_bytes,
           nw->nw_lock.fh.n_len);
       nw->nw_lock.fh.n_bytes = nw->nw_fh.fh_bytes;
       nw->nw_waiting = TRUE;
       nw->nw_vp = vp;
       mtx_lock(&nlm_global_lock);
       TAILQ_INSERT_TAIL(&nlm_waiting_locks, nw, nw_link);
       mtx_unlock(&nlm_global_lock);

       return nw;
}

void
nlm_deregister_wait_lock(void *handle)
{
       struct nlm_waiting_lock *nw = handle;

       mtx_lock(&nlm_global_lock);
       TAILQ_REMOVE(&nlm_waiting_locks, nw, nw_link);
       mtx_unlock(&nlm_global_lock);

       free(nw, M_NLM);
}

int
nlm_wait_lock(void *handle, int timo)
{
       struct nlm_waiting_lock *nw = handle;
       int error, stops_deferred;

       /*
        * If the granted message arrived before we got here,
        * nw->nw_waiting will be FALSE - in that case, don't sleep.
        */
       mtx_lock(&nlm_global_lock);
       error = 0;
       if (nw->nw_waiting) {
               stops_deferred = sigdeferstop(SIGDEFERSTOP_ERESTART);
               error = msleep(nw, &nlm_global_lock, PCATCH, "nlmlock", timo);
               sigallowstop(stops_deferred);
       }
       TAILQ_REMOVE(&nlm_waiting_locks, nw, nw_link);
       if (error) {
               /*
                * The granted message may arrive after the
                * interrupt/timeout but before we manage to lock the
                * mutex. Detect this by examining nw_lock.
                */
               if (!nw->nw_waiting)
                       error = 0;
       } else {
               /*
                * If nlm_cancel_wait is called, then error will be
                * zero but nw_waiting will still be TRUE. We
                * translate this into EINTR.
                */
               if (nw->nw_waiting)
                       error = EINTR;
       }
       mtx_unlock(&nlm_global_lock);

       free(nw, M_NLM);

       return (error);
}

void
nlm_cancel_wait(struct vnode *vp)
{
       struct nlm_waiting_lock *nw;

       mtx_lock(&nlm_global_lock);
       TAILQ_FOREACH(nw, &nlm_waiting_locks, nw_link) {
               if (nw->nw_vp == vp) {
                       wakeup(nw);
               }
       }
       mtx_unlock(&nlm_global_lock);
}


/**********************************************************************/

/*
* Syscall interface with userland.
*/

extern void nlm_prog_0(struct svc_req *rqstp, SVCXPRT *transp);
extern void nlm_prog_1(struct svc_req *rqstp, SVCXPRT *transp);
extern void nlm_prog_3(struct svc_req *rqstp, SVCXPRT *transp);
extern void nlm_prog_4(struct svc_req *rqstp, SVCXPRT *transp);

static int
nlm_register_services(SVCPOOL *pool, int addr_count, char **addrs)
{
       static rpcvers_t versions[] = {
               NLM_SM, NLM_VERS, NLM_VERSX, NLM_VERS4
       };
       static void (*dispatchers[])(struct svc_req *, SVCXPRT *) = {
               nlm_prog_0, nlm_prog_1, nlm_prog_3, nlm_prog_4
       };

       SVCXPRT **xprts;
       char netid[16];
       char uaddr[128];
       struct netconfig *nconf;
       int i, j, error;

       if (!addr_count) {
               NLM_ERR("NLM: no service addresses given - can't start server");
               return (EINVAL);
       }

       if (addr_count < 0 || addr_count > 256 ) {
               NLM_ERR("NLM:  too many service addresses (%d) given, "
                   "max 256 - can't start server\n", addr_count);
               return (EINVAL);
       }

       xprts = malloc(addr_count * sizeof(SVCXPRT *), M_NLM, M_WAITOK|M_ZERO);
       for (i = 0; i < nitems(versions); i++) {
               for (j = 0; j < addr_count; j++) {
                       /*
                        * Create transports for the first version and
                        * then just register everything else to the
                        * same transports.
                        */
                       if (i == 0) {
                               char *up;

                               error = copyin(&addrs[2*j], &up,
                                   sizeof(char*));
                               if (error)
                                       goto out;
                               error = copyinstr(up, netid, sizeof(netid),
                                   NULL);
                               if (error)
                                       goto out;
                               error = copyin(&addrs[2*j+1], &up,
                                   sizeof(char*));
                               if (error)
                                       goto out;
                               error = copyinstr(up, uaddr, sizeof(uaddr),
                                   NULL);
                               if (error)
                                       goto out;
                               nconf = getnetconfigent(netid);
                               if (!nconf) {
                                       NLM_ERR("Can't lookup netid %s\n",
                                           netid);
                                       error = EINVAL;
                                       goto out;
                               }
                               xprts[j] = svc_tp_create(pool, dispatchers[i],
                                   NLM_PROG, versions[i], uaddr, nconf);
                               if (!xprts[j]) {
                                       NLM_ERR("NLM: unable to create "
                                           "(NLM_PROG, %d).\n", versions[i]);
                                       error = EINVAL;
                                       goto out;
                               }
                               freenetconfigent(nconf);
                       } else {
                               nconf = getnetconfigent(xprts[j]->xp_netid);
                               rpcb_unset(NLM_PROG, versions[i], nconf);
                               if (!svc_reg(xprts[j], NLM_PROG, versions[i],
                                       dispatchers[i], nconf)) {
                                       NLM_ERR("NLM: can't register "
                                           "(NLM_PROG, %d)\n", versions[i]);
                                       error = EINVAL;
                                       goto out;
                               }
                       }
               }
       }
       error = 0;
out:
       for (j = 0; j < addr_count; j++) {
               if (xprts[j])
                       SVC_RELEASE(xprts[j]);
       }
       free(xprts, M_NLM);
       return (error);
}

/*
* Main server entry point. Contacts the local NSM to get its current
* state and send SM_UNMON_ALL. Registers the NLM services and then
* services requests. Does not return until the server is interrupted
* by a signal.
*/
static int
nlm_server_main(int addr_count, char **addrs)
{
       struct thread *td = curthread;
       int error;
       SVCPOOL *pool = NULL;
       struct sockopt opt;
       int portlow;
#ifdef INET6
       struct sockaddr_in6 sin6;
#endif
       struct sockaddr_in sin;
       my_id id;
       sm_stat smstat;
       struct timeval timo;
       enum clnt_stat stat;
       struct nlm_host *host, *nhost;
       struct nlm_waiting_lock *nw;
       vop_advlock_t *old_nfs_advlock;
       vop_reclaim_t *old_nfs_reclaim;

       if (nlm_is_running != 0) {
               NLM_ERR("NLM: can't start server - "
                   "it appears to be running already\n");
               return (EPERM);
       }

       if (nlm_socket == NULL) {
               memset(&opt, 0, sizeof(opt));

               error = socreate(AF_INET, &nlm_socket, SOCK_DGRAM, 0,
                   td->td_ucred, td);
               if (error) {
                       NLM_ERR("NLM: can't create IPv4 socket - error %d\n",
                           error);
                       return (error);
               }
               opt.sopt_dir = SOPT_SET;
               opt.sopt_level = IPPROTO_IP;
               opt.sopt_name = IP_PORTRANGE;
               portlow = IP_PORTRANGE_LOW;
               opt.sopt_val = &portlow;
               opt.sopt_valsize = sizeof(portlow);
               sosetopt(nlm_socket, &opt);

#ifdef INET6
               nlm_socket6 = NULL;
               error = socreate(AF_INET6, &nlm_socket6, SOCK_DGRAM, 0,
                   td->td_ucred, td);
               if (error) {
                       NLM_ERR("NLM: can't create IPv6 socket - error %d\n",
                           error);
                       soclose(nlm_socket);
                       nlm_socket = NULL;
                       return (error);
               }
               opt.sopt_dir = SOPT_SET;
               opt.sopt_level = IPPROTO_IPV6;
               opt.sopt_name = IPV6_PORTRANGE;
               portlow = IPV6_PORTRANGE_LOW;
               opt.sopt_val = &portlow;
               opt.sopt_valsize = sizeof(portlow);
               sosetopt(nlm_socket6, &opt);
#endif
       }

       nlm_auth = authunix_create(curthread->td_ucred);

#ifdef INET6
       memset(&sin6, 0, sizeof(sin6));
       sin6.sin6_len = sizeof(sin6);
       sin6.sin6_family = AF_INET6;
       sin6.sin6_addr = in6addr_loopback;
       nlm_nsm = nlm_get_rpc((struct sockaddr *) &sin6, SM_PROG, SM_VERS);
       if (!nlm_nsm) {
#endif
               memset(&sin, 0, sizeof(sin));
               sin.sin_len = sizeof(sin);
               sin.sin_family = AF_INET;
               sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
               nlm_nsm = nlm_get_rpc((struct sockaddr *) &sin, SM_PROG,
                   SM_VERS);
#ifdef INET6
       }
#endif

       if (!nlm_nsm) {
               NLM_ERR("Can't start NLM - unable to contact NSM\n");
               error = EINVAL;
               goto out;
       }

       pool = svcpool_create("NLM", NULL);

       error = nlm_register_services(pool, addr_count, addrs);
       if (error)
               goto out;

       memset(&id, 0, sizeof(id));
       id.my_name = "NFS NLM";

       timo.tv_sec = 25;
       timo.tv_usec = 0;
       stat = CLNT_CALL(nlm_nsm, SM_UNMON_ALL,
           (xdrproc_t) xdr_my_id, &id,
           (xdrproc_t) xdr_sm_stat, &smstat, timo);

       if (stat != RPC_SUCCESS) {
               struct rpc_err err;

               CLNT_GETERR(nlm_nsm, &err);
               NLM_ERR("NLM: unexpected error contacting NSM, "
                   "stat=%d, errno=%d\n", stat, err.re_errno);
               error = EINVAL;
               goto out;
       }
       nlm_is_running = 1;

       NLM_DEBUG(1, "NLM: local NSM state is %d\n", smstat.state);
       nlm_nsm_state = smstat.state;

       old_nfs_advlock = nfs_advlock_p;
       nfs_advlock_p = nlm_advlock;
       old_nfs_reclaim = nfs_reclaim_p;
       nfs_reclaim_p = nlm_reclaim;

       svc_run(pool);
       error = 0;

       nfs_advlock_p = old_nfs_advlock;
       nfs_reclaim_p = old_nfs_reclaim;

out:
       nlm_is_running = 0;
       if (pool)
               svcpool_destroy(pool);

       /*
        * We are finished communicating with the NSM.
        */
       if (nlm_nsm) {
               CLNT_RELEASE(nlm_nsm);
               nlm_nsm = NULL;
       }

       /*
        * Trash all the existing state so that if the server
        * restarts, it gets a clean slate. This is complicated by the
        * possibility that there may be other threads trying to make
        * client locking requests.
        *
        * First we fake a client reboot notification which will
        * cancel any pending async locks and purge remote lock state
        * from the local lock manager. We release the reference from
        * nlm_hosts to the host (which may remove it from the list
        * and free it). After this phase, the only entries in the
        * nlm_host list should be from other threads performing
        * client lock requests.
        */
       mtx_lock(&nlm_global_lock);
       TAILQ_FOREACH(nw, &nlm_waiting_locks, nw_link) {
               wakeup(nw);
       }
       TAILQ_FOREACH_SAFE(host, &nlm_hosts, nh_link, nhost) {
               mtx_unlock(&nlm_global_lock);
               nlm_host_notify(host, 0);
               nlm_host_release(host);
               mtx_lock(&nlm_global_lock);
       }
       mtx_unlock(&nlm_global_lock);

       AUTH_DESTROY(nlm_auth);

       return (error);
}

int
sys_nlm_syscall(struct thread *td, struct nlm_syscall_args *uap)
{
       int error;

#if __FreeBSD_version >= 700000
       error = priv_check(td, PRIV_NFS_LOCKD);
#else
       error = suser(td);
#endif
       if (error)
               return (error);

       nlm_debug_level = uap->debug_level;
       nlm_grace_threshold = time_uptime + uap->grace_period;
       nlm_next_idle_check = time_uptime + NLM_IDLE_PERIOD;

       return nlm_server_main(uap->addr_count, uap->addrs);
}

/**********************************************************************/

/*
* NLM implementation details, called from the RPC stubs.
*/


void
nlm_sm_notify(struct nlm_sm_status *argp)
{
       uint32_t sysid;
       struct nlm_host *host;

       NLM_DEBUG(3, "nlm_sm_notify(): mon_name = %s\n", argp->mon_name);
       memcpy(&sysid, &argp->priv, sizeof(sysid));
       host = nlm_find_host_by_sysid(sysid);
       if (host) {
               nlm_host_notify(host, argp->state);
               nlm_host_release(host);
       }
}

static void
nlm_convert_to_fhandle_t(fhandle_t *fhp, struct netobj *p)
{
       memcpy(fhp, p->n_bytes, sizeof(fhandle_t));
}

struct vfs_state {
       struct mount    *vs_mp;
       struct vnode    *vs_vp;
       int             vs_vnlocked;
};

static int
nlm_get_vfs_state(struct nlm_host *host, struct svc_req *rqstp,
   fhandle_t *fhp, struct vfs_state *vs, accmode_t accmode)
{
       int error, exflags;
       struct ucred *cred = NULL, *credanon = NULL;

       memset(vs, 0, sizeof(*vs));

       vs->vs_mp = vfs_getvfs(&fhp->fh_fsid);
       if (!vs->vs_mp) {
               return (ESTALE);
       }

       /* accmode == 0 means don't check, since it is an unlock. */
       if (accmode != 0) {
               error = VFS_CHECKEXP(vs->vs_mp,
                   (struct sockaddr *)&host->nh_addr, &exflags, &credanon,
                   NULL, NULL);
               if (error)
                       goto out;

               if (exflags & MNT_EXRDONLY ||
                   (vs->vs_mp->mnt_flag & MNT_RDONLY)) {
                       error = EROFS;
                       goto out;
               }
       }

       error = VFS_FHTOVP(vs->vs_mp, &fhp->fh_fid, LK_EXCLUSIVE, &vs->vs_vp);
       if (error)
               goto out;
       vs->vs_vnlocked = TRUE;

       if (accmode != 0) {
               if (!svc_getcred(rqstp, &cred, NULL)) {
                       error = EINVAL;
                       goto out;
               }
               if (cred->cr_uid == 0 || (exflags & MNT_EXPORTANON)) {
                       crfree(cred);
                       cred = credanon;
                       credanon = NULL;
               }

               /*
                * Check cred.
                */
               error = VOP_ACCESS(vs->vs_vp, accmode, cred, curthread);
               /*
                * If this failed and accmode != VWRITE, try again with
                * VWRITE to maintain backwards compatibility with the
                * old code that always used VWRITE.
                */
               if (error != 0 && accmode != VWRITE)
                       error = VOP_ACCESS(vs->vs_vp, VWRITE, cred, curthread);
               if (error)
                       goto out;
       }

#if __FreeBSD_version < 800011
       VOP_UNLOCK(vs->vs_vp, 0, curthread);
#else
       VOP_UNLOCK(vs->vs_vp, 0);
#endif
       vs->vs_vnlocked = FALSE;

out:
       if (cred)
               crfree(cred);
       if (credanon)
               crfree(credanon);

       return (error);
}

static void
nlm_release_vfs_state(struct vfs_state *vs)
{

       if (vs->vs_vp) {
               if (vs->vs_vnlocked)
                       vput(vs->vs_vp);
               else
                       vrele(vs->vs_vp);
       }
       if (vs->vs_mp)
               vfs_rel(vs->vs_mp);
}

static nlm4_stats
nlm_convert_error(int error)
{

       if (error == ESTALE)
               return nlm4_stale_fh;
       else if (error == EROFS)
               return nlm4_rofs;
       else
               return nlm4_failed;
}

int
nlm_do_test(nlm4_testargs *argp, nlm4_testres *result, struct svc_req *rqstp,
       CLIENT **rpcp)
{
       fhandle_t fh;
       struct vfs_state vs;
       struct nlm_host *host, *bhost;
       int error, sysid;
       struct flock fl;
       accmode_t accmode;

       memset(result, 0, sizeof(*result));
       memset(&vs, 0, sizeof(vs));

       host = nlm_find_host_by_name(argp->alock.caller_name,
           svc_getrpccaller(rqstp), rqstp->rq_vers);
       if (!host) {
               result->stat.stat = nlm4_denied_nolocks;
               return (ENOMEM);
       }

       NLM_DEBUG(3, "nlm_do_test(): caller_name = %s (sysid = %d)\n",
           host->nh_caller_name, host->nh_sysid);

       nlm_check_expired_locks(host);
       sysid = host->nh_sysid;

       nlm_convert_to_fhandle_t(&fh, &argp->alock.fh);
       nlm_copy_netobj(&result->cookie, &argp->cookie, M_RPC);

       if (time_uptime < nlm_grace_threshold) {
               result->stat.stat = nlm4_denied_grace_period;
               goto out;
       }

       accmode = argp->exclusive ? VWRITE : VREAD;
       error = nlm_get_vfs_state(host, rqstp, &fh, &vs, accmode);
       if (error) {
               result->stat.stat = nlm_convert_error(error);
               goto out;
       }

       fl.l_start = argp->alock.l_offset;
       fl.l_len = argp->alock.l_len;
       fl.l_pid = argp->alock.svid;
       fl.l_sysid = sysid;
       fl.l_whence = SEEK_SET;
       if (argp->exclusive)
               fl.l_type = F_WRLCK;
       else
               fl.l_type = F_RDLCK;
       error = VOP_ADVLOCK(vs.vs_vp, NULL, F_GETLK, &fl, F_REMOTE);
       if (error) {
               result->stat.stat = nlm4_failed;
               goto out;
       }

       if (fl.l_type == F_UNLCK) {
               result->stat.stat = nlm4_granted;
       } else {
               result->stat.stat = nlm4_denied;
               result->stat.nlm4_testrply_u.holder.exclusive =
                       (fl.l_type == F_WRLCK);
               result->stat.nlm4_testrply_u.holder.svid = fl.l_pid;
               bhost = nlm_find_host_by_sysid(fl.l_sysid);
               if (bhost) {
                       /*
                        * We don't have any useful way of recording
                        * the value of oh used in the original lock
                        * request. Ideally, the test reply would have
                        * a space for the owning host's name allowing
                        * our caller's NLM to keep track.
                        *
                        * As far as I can see, Solaris uses an eight
                        * byte structure for oh which contains a four
                        * byte pid encoded in local byte order and
                        * the first four bytes of the host
                        * name. Linux uses a variable length string
                        * 'pid@hostname' in ascii but doesn't even
                        * return that in test replies.
                        *
                        * For the moment, return nothing in oh
                        * (already zero'ed above).
                        */
                       nlm_host_release(bhost);
               }
               result->stat.nlm4_testrply_u.holder.l_offset = fl.l_start;
               result->stat.nlm4_testrply_u.holder.l_len = fl.l_len;
       }

out:
       nlm_release_vfs_state(&vs);
       if (rpcp)
               *rpcp = nlm_host_get_rpc(host, TRUE);
       nlm_host_release(host);
       return (0);
}

int
nlm_do_lock(nlm4_lockargs *argp, nlm4_res *result, struct svc_req *rqstp,
   bool_t monitor, CLIENT **rpcp)
{
       fhandle_t fh;
       struct vfs_state vs;
       struct nlm_host *host;
       int error, sysid;
       struct flock fl;
       accmode_t accmode;

       memset(result, 0, sizeof(*result));
       memset(&vs, 0, sizeof(vs));

       host = nlm_find_host_by_name(argp->alock.caller_name,
           svc_getrpccaller(rqstp), rqstp->rq_vers);
       if (!host) {
               result->stat.stat = nlm4_denied_nolocks;
               return (ENOMEM);
       }

       NLM_DEBUG(3, "nlm_do_lock(): caller_name = %s (sysid = %d)\n",
           host->nh_caller_name, host->nh_sysid);

       if (monitor && host->nh_state && argp->state
           && host->nh_state != argp->state) {
               /*
                * The host rebooted without telling us. Trash its
                * locks.
                */
               nlm_host_notify(host, argp->state);
       }

       nlm_check_expired_locks(host);
       sysid = host->nh_sysid;

       nlm_convert_to_fhandle_t(&fh, &argp->alock.fh);
       nlm_copy_netobj(&result->cookie, &argp->cookie, M_RPC);

       if (time_uptime < nlm_grace_threshold && !argp->reclaim) {
               result->stat.stat = nlm4_denied_grace_period;
               goto out;
       }

       accmode = argp->exclusive ? VWRITE : VREAD;
       error = nlm_get_vfs_state(host, rqstp, &fh, &vs, accmode);
       if (error) {
               result->stat.stat = nlm_convert_error(error);
               goto out;
       }

       fl.l_start = argp->alock.l_offset;
       fl.l_len = argp->alock.l_len;
       fl.l_pid = argp->alock.svid;
       fl.l_sysid = sysid;
       fl.l_whence = SEEK_SET;
       if (argp->exclusive)
               fl.l_type = F_WRLCK;
       else
               fl.l_type = F_RDLCK;
       if (argp->block) {
               struct nlm_async_lock *af;
               CLIENT *client;
               struct nlm_grantcookie cookie;

               /*
                * First, make sure we can contact the host's NLM.
                */
               client = nlm_host_get_rpc(host, TRUE);
               if (!client) {
                       result->stat.stat = nlm4_failed;
                       goto out;
               }

               /*
                * First we need to check and see if there is an
                * existing blocked lock that matches. This could be a
                * badly behaved client or an RPC re-send. If we find
                * one, just return nlm4_blocked.
                */
               mtx_lock(&host->nh_lock);
               TAILQ_FOREACH(af, &host->nh_pending, af_link) {
                       if (af->af_fl.l_start == fl.l_start
                           && af->af_fl.l_len == fl.l_len
                           && af->af_fl.l_pid == fl.l_pid
                           && af->af_fl.l_type == fl.l_type) {
                               break;
                       }
               }
               if (!af) {
                       cookie.ng_sysid = host->nh_sysid;
                       cookie.ng_cookie = host->nh_grantcookie++;
               }
               mtx_unlock(&host->nh_lock);
               if (af) {
                       CLNT_RELEASE(client);
                       result->stat.stat = nlm4_blocked;
                       goto out;
               }

               af = malloc(sizeof(struct nlm_async_lock), M_NLM,
                   M_WAITOK|M_ZERO);
               TASK_INIT(&af->af_task, 0, nlm_lock_callback, af);
               af->af_vp = vs.vs_vp;
               af->af_fl = fl;
               af->af_host = host;
               af->af_rpc = client;
               /*
                * We use M_RPC here so that we can xdr_free the thing
                * later.
                */
               nlm_make_netobj(&af->af_granted.cookie,
                   (caddr_t)&cookie, sizeof(cookie), M_RPC);
               af->af_granted.exclusive = argp->exclusive;
               af->af_granted.alock.caller_name =
                       strdup(argp->alock.caller_name, M_RPC);
               nlm_copy_netobj(&af->af_granted.alock.fh,
                   &argp->alock.fh, M_RPC);
               nlm_copy_netobj(&af->af_granted.alock.oh,
                   &argp->alock.oh, M_RPC);
               af->af_granted.alock.svid = argp->alock.svid;
               af->af_granted.alock.l_offset = argp->alock.l_offset;
               af->af_granted.alock.l_len = argp->alock.l_len;

               /*
                * Put the entry on the pending list before calling
                * VOP_ADVLOCKASYNC. We do this in case the lock
                * request was blocked (returning EINPROGRESS) but
                * then granted before we manage to run again. The
                * client may receive the granted message before we
                * send our blocked reply but thats their problem.
                */
               mtx_lock(&host->nh_lock);
               TAILQ_INSERT_TAIL(&host->nh_pending, af, af_link);
               mtx_unlock(&host->nh_lock);

               error = VOP_ADVLOCKASYNC(vs.vs_vp, NULL, F_SETLK, &fl, F_REMOTE,
                   &af->af_task, &af->af_cookie);

               /*
                * If the lock completed synchronously, just free the
                * tracking structure now.
                */
               if (error != EINPROGRESS) {
                       CLNT_RELEASE(af->af_rpc);
                       mtx_lock(&host->nh_lock);
                       TAILQ_REMOVE(&host->nh_pending, af, af_link);
                       mtx_unlock(&host->nh_lock);
                       xdr_free((xdrproc_t) xdr_nlm4_testargs,
                           &af->af_granted);
                       free(af, M_NLM);
               } else {
                       NLM_DEBUG(2, "NLM: pending async lock %p for %s "
                           "(sysid %d)\n", af, host->nh_caller_name, sysid);
                       /*
                        * Don't vrele the vnode just yet - this must
                        * wait until either the async callback
                        * happens or the lock is cancelled.
                        */
                       vs.vs_vp = NULL;
               }
       } else {
               error = VOP_ADVLOCK(vs.vs_vp, NULL, F_SETLK, &fl, F_REMOTE);
       }

       if (error) {
               if (error == EINPROGRESS) {
                       result->stat.stat = nlm4_blocked;
               } else if (error == EDEADLK) {
                       result->stat.stat = nlm4_deadlck;
               } else if (error == EAGAIN) {
                       result->stat.stat = nlm4_denied;
               } else {
                       result->stat.stat = nlm4_failed;
               }
       } else {
               if (monitor)
                       nlm_host_monitor(host, argp->state);
               result->stat.stat = nlm4_granted;
       }

out:
       nlm_release_vfs_state(&vs);
       if (rpcp)
               *rpcp = nlm_host_get_rpc(host, TRUE);
       nlm_host_release(host);
       return (0);
}

int
nlm_do_cancel(nlm4_cancargs *argp, nlm4_res *result, struct svc_req *rqstp,
   CLIENT **rpcp)
{
       fhandle_t fh;
       struct vfs_state vs;
       struct nlm_host *host;
       int error, sysid;
       struct flock fl;
       struct nlm_async_lock *af;

       memset(result, 0, sizeof(*result));
       memset(&vs, 0, sizeof(vs));

       host = nlm_find_host_by_name(argp->alock.caller_name,
           svc_getrpccaller(rqstp), rqstp->rq_vers);
       if (!host) {
               result->stat.stat = nlm4_denied_nolocks;
               return (ENOMEM);
       }

       NLM_DEBUG(3, "nlm_do_cancel(): caller_name = %s (sysid = %d)\n",
           host->nh_caller_name, host->nh_sysid);

       nlm_check_expired_locks(host);
       sysid = host->nh_sysid;

       nlm_convert_to_fhandle_t(&fh, &argp->alock.fh);
       nlm_copy_netobj(&result->cookie, &argp->cookie, M_RPC);

       if (time_uptime < nlm_grace_threshold) {
               result->stat.stat = nlm4_denied_grace_period;
               goto out;
       }

       error = nlm_get_vfs_state(host, rqstp, &fh, &vs, (accmode_t)0);
       if (error) {
               result->stat.stat = nlm_convert_error(error);
               goto out;
       }

       fl.l_start = argp->alock.l_offset;
       fl.l_len = argp->alock.l_len;
       fl.l_pid = argp->alock.svid;
       fl.l_sysid = sysid;
       fl.l_whence = SEEK_SET;
       if (argp->exclusive)
               fl.l_type = F_WRLCK;
       else
               fl.l_type = F_RDLCK;

       /*
        * First we need to try and find the async lock request - if
        * there isn't one, we give up and return nlm4_denied.
        */
       mtx_lock(&host->nh_lock);

       TAILQ_FOREACH(af, &host->nh_pending, af_link) {
               if (af->af_fl.l_start == fl.l_start
                   && af->af_fl.l_len == fl.l_len
                   && af->af_fl.l_pid == fl.l_pid
                   && af->af_fl.l_type == fl.l_type) {
                       break;
               }
       }

       if (!af) {
               mtx_unlock(&host->nh_lock);
               result->stat.stat = nlm4_denied;
               goto out;
       }

       error = nlm_cancel_async_lock(af);

       if (error) {
               result->stat.stat = nlm4_denied;
       } else {
               result->stat.stat = nlm4_granted;
       }

       mtx_unlock(&host->nh_lock);

out:
       nlm_release_vfs_state(&vs);
       if (rpcp)
               *rpcp = nlm_host_get_rpc(host, TRUE);
       nlm_host_release(host);
       return (0);
}

int
nlm_do_unlock(nlm4_unlockargs *argp, nlm4_res *result, struct svc_req *rqstp,
   CLIENT **rpcp)
{
       fhandle_t fh;
       struct vfs_state vs;
       struct nlm_host *host;
       int error, sysid;
       struct flock fl;

       memset(result, 0, sizeof(*result));
       memset(&vs, 0, sizeof(vs));

       host = nlm_find_host_by_name(argp->alock.caller_name,
           svc_getrpccaller(rqstp), rqstp->rq_vers);
       if (!host) {
               result->stat.stat = nlm4_denied_nolocks;
               return (ENOMEM);
       }

       NLM_DEBUG(3, "nlm_do_unlock(): caller_name = %s (sysid = %d)\n",
           host->nh_caller_name, host->nh_sysid);

       nlm_check_expired_locks(host);
       sysid = host->nh_sysid;

       nlm_convert_to_fhandle_t(&fh, &argp->alock.fh);
       nlm_copy_netobj(&result->cookie, &argp->cookie, M_RPC);

       if (time_uptime < nlm_grace_threshold) {
               result->stat.stat = nlm4_denied_grace_period;
               goto out;
       }

       error = nlm_get_vfs_state(host, rqstp, &fh, &vs, (accmode_t)0);
       if (error) {
               result->stat.stat = nlm_convert_error(error);
               goto out;
       }

       fl.l_start = argp->alock.l_offset;
       fl.l_len = argp->alock.l_len;
       fl.l_pid = argp->alock.svid;
       fl.l_sysid = sysid;
       fl.l_whence = SEEK_SET;
       fl.l_type = F_UNLCK;
       error = VOP_ADVLOCK(vs.vs_vp, NULL, F_UNLCK, &fl, F_REMOTE);

       /*
        * Ignore the error - there is no result code for failure,
        * only for grace period.
        */
       result->stat.stat = nlm4_granted;

out:
       nlm_release_vfs_state(&vs);
       if (rpcp)
               *rpcp = nlm_host_get_rpc(host, TRUE);
       nlm_host_release(host);
       return (0);
}

int
nlm_do_granted(nlm4_testargs *argp, nlm4_res *result, struct svc_req *rqstp,

   CLIENT **rpcp)
{
       struct nlm_host *host;
       struct nlm_waiting_lock *nw;

       memset(result, 0, sizeof(*result));

       host = nlm_find_host_by_addr(svc_getrpccaller(rqstp), rqstp->rq_vers);
       if (!host) {
               result->stat.stat = nlm4_denied_nolocks;
               return (ENOMEM);
       }

       nlm_copy_netobj(&result->cookie, &argp->cookie, M_RPC);
       result->stat.stat = nlm4_denied;
       KFAIL_POINT_CODE(DEBUG_FP, nlm_deny_grant, goto out);

       mtx_lock(&nlm_global_lock);
       TAILQ_FOREACH(nw, &nlm_waiting_locks, nw_link) {
               if (!nw->nw_waiting)
                       continue;
               if (argp->alock.svid == nw->nw_lock.svid
                   && argp->alock.l_offset == nw->nw_lock.l_offset
                   && argp->alock.l_len == nw->nw_lock.l_len
                   && argp->alock.fh.n_len == nw->nw_lock.fh.n_len
                   && !memcmp(argp->alock.fh.n_bytes, nw->nw_lock.fh.n_bytes,
                       nw->nw_lock.fh.n_len)) {
                       nw->nw_waiting = FALSE;
                       wakeup(nw);
                       result->stat.stat = nlm4_granted;
                       break;
               }
       }
       mtx_unlock(&nlm_global_lock);

out:
       if (rpcp)
               *rpcp = nlm_host_get_rpc(host, TRUE);
       nlm_host_release(host);
       return (0);
}

void
nlm_do_granted_res(nlm4_res *argp, struct svc_req *rqstp)
{
       struct nlm_host *host = NULL;
       struct nlm_async_lock *af = NULL;
       int error;

       if (argp->cookie.n_len != sizeof(struct nlm_grantcookie)) {
               NLM_DEBUG(1, "NLM: bogus grant cookie");
               goto out;
       }

       host = nlm_find_host_by_sysid(ng_sysid(&argp->cookie));
       if (!host) {
               NLM_DEBUG(1, "NLM: Unknown host rejected our grant");
               goto out;
       }

       mtx_lock(&host->nh_lock);
       TAILQ_FOREACH(af, &host->nh_granted, af_link)
           if (ng_cookie(&argp->cookie) ==
               ng_cookie(&af->af_granted.cookie))
                   break;
       if (af)
               TAILQ_REMOVE(&host->nh_granted, af, af_link);
       mtx_unlock(&host->nh_lock);

       if (!af) {
               NLM_DEBUG(1, "NLM: host %s (sysid %d) replied to our grant "
                   "with unrecognized cookie %d:%d", host->nh_caller_name,
                   host->nh_sysid, ng_sysid(&argp->cookie),
                   ng_cookie(&argp->cookie));
               goto out;
       }

       if (argp->stat.stat != nlm4_granted) {
               af->af_fl.l_type = F_UNLCK;
               error = VOP_ADVLOCK(af->af_vp, NULL, F_UNLCK, &af->af_fl, F_REMOTE);
               if (error) {
                       NLM_DEBUG(1, "NLM: host %s (sysid %d) rejected our grant "
                           "and we failed to unlock (%d)", host->nh_caller_name,
                           host->nh_sysid, error);
                       goto out;
               }

               NLM_DEBUG(5, "NLM: async lock %p rejected by host %s (sysid %d)",
                   af, host->nh_caller_name, host->nh_sysid);
       } else {
               NLM_DEBUG(5, "NLM: async lock %p accepted by host %s (sysid %d)",
                   af, host->nh_caller_name, host->nh_sysid);
       }

out:
       if (af)
               nlm_free_async_lock(af);
       if (host)
               nlm_host_release(host);
}

void
nlm_do_free_all(nlm4_notify *argp)
{
       struct nlm_host *host, *thost;

       TAILQ_FOREACH_SAFE(host, &nlm_hosts, nh_link, thost) {
               if (!strcmp(host->nh_caller_name, argp->name))
                       nlm_host_notify(host, argp->state);
       }
}

/*
* Kernel module glue
*/
static int
nfslockd_modevent(module_t mod, int type, void *data)
{

       switch (type) {
       case MOD_LOAD:
               return (0);
       case MOD_UNLOAD:
               /* The NLM module cannot be safely unloaded. */
               /* FALLTHROUGH */
       default:
               return (EOPNOTSUPP);
       }
}
static moduledata_t nfslockd_mod = {
       "nfslockd",
       nfslockd_modevent,
       NULL,
};
DECLARE_MODULE(nfslockd, nfslockd_mod, SI_SUB_VFS, SI_ORDER_ANY);

/* So that loader and kldload(2) can find us, wherever we are.. */
MODULE_DEPEND(nfslockd, krpc, 1, 1, 1);
MODULE_DEPEND(nfslockd, nfslock, 1, 1, 1);
MODULE_VERSION(nfslockd, 1);