/*
   * linux/fs/lockd/svc.c
   *
   * This is the central lockd service.
   *
   * FIXME: Separate the lockd NFS server functionality from the lockd NFS
   * 	  client functionality. Oh why didn't Sun create two separate
   *	  services in the first place?
   *
   * Authors:	Olaf Kirch (okir@monad.swb.de)
   *
   * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   */

  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/sysctl.h>
  #include <linux/moduleparam.h>
  
  #include <linux/sched.h>
  #include <linux/errno.h>
  #include <linux/in.h>
  #include <linux/uio.h>

  #include <linux/smp.h>

  #include <linux/mutex.h>

  #include <linux/kthread.h>

  #include <linux/freezer.h>

  
  #include <linux/sunrpc/types.h>
  #include <linux/sunrpc/stats.h>
  #include <linux/sunrpc/clnt.h>
  #include <linux/sunrpc/svc.h>
  #include <linux/sunrpc/svcsock.h>

  #include <net/ip.h>

  #include <linux/lockd/lockd.h>
  #include <linux/nfs.h>
  
  #define NLMDBG_FACILITY		NLMDBG_SVC
  #define LOCKD_BUFSIZE		(1024 + NLMSVC_XDRSIZE)
  #define ALLOWED_SIGS		(sigmask(SIGKILL))
  
  static struct svc_program	nlmsvc_program;
  
  struct nlmsvc_binding *		nlmsvc_ops;

  EXPORT_SYMBOL_GPL(nlmsvc_ops);

  static DEFINE_MUTEX(nlmsvc_mutex);

  static unsigned int		nlmsvc_users;

  static struct task_struct	*nlmsvc_task;

  static struct svc_rqst		*nlmsvc_rqst;

  unsigned long			nlmsvc_timeout;

  /*
   * These can be set at insmod time (useful for NFS as root filesystem),
   * and also changed through the sysctl interface.  -- Jamie Lokier, Aug 2003
   */
  static unsigned long		nlm_grace_period;
  static unsigned long		nlm_timeout = LOCKD_DFLT_TIMEO;
  static int			nlm_udpport, nlm_tcpport;

  /* RLIM_NOFILE defaults to 1024. That seems like a reasonable default here. */
  static unsigned int		nlm_max_connections = 1024;

  /*
   * Constants needed for the sysctl interface.
   */
  static const unsigned long	nlm_grace_period_min = 0;
  static const unsigned long	nlm_grace_period_max = 240;
  static const unsigned long	nlm_timeout_min = 3;
  static const unsigned long	nlm_timeout_max = 20;
  static const int		nlm_port_min = 0, nlm_port_max = 65535;

  #ifdef CONFIG_SYSCTL

  static struct ctl_table_header * nlm_sysctl_table;

  #endif

  static unsigned long get_lockd_grace_period(void)

  {

  	/* Note: nlm_timeout should always be nonzero */
  	if (nlm_grace_period)

  		return roundup(nlm_grace_period, nlm_timeout) * HZ;

  	else

  		return nlm_timeout * 5 * HZ;
  }

  static struct lock_manager lockd_manager = {
  };

  static void grace_ender(struct work_struct *not_used)

  {

  	locks_end_grace(&lockd_manager);

  }

  static DECLARE_DELAYED_WORK(grace_period_end, grace_ender);
  
  static void set_grace_period(void)

  {

  	unsigned long grace_period = get_lockd_grace_period();

  	locks_start_grace(&lockd_manager);

  	cancel_delayed_work_sync(&grace_period_end);
  	schedule_delayed_work(&grace_period_end, grace_period);

  }

  static void restart_grace(void)
  {
  	if (nlmsvc_ops) {
  		cancel_delayed_work_sync(&grace_period_end);
  		locks_end_grace(&lockd_manager);
  		nlmsvc_invalidate_all();
  		set_grace_period();
  	}
  }

  /*
   * This is the lockd kernel thread
   */

  static int
  lockd(void *vrqstp)

  {

  	int		err = 0, preverr = 0;

  	struct svc_rqst *rqstp = vrqstp;

  	/* try_to_freeze() is called from svc_recv() */

  	set_freezable();

  	/* Allow SIGKILL to tell lockd to drop all of its locks */

  	allow_signal(SIGKILL);

  	dprintk("NFS locking service started (ver " LOCKD_VERSION ").
  ");
  
  	if (!nlm_timeout)
  		nlm_timeout = LOCKD_DFLT_TIMEO;
  	nlmsvc_timeout = nlm_timeout * HZ;

  	set_grace_period();

  
  	/*
  	 * The main request loop. We don't terminate until the last

  	 * NFS mount or NFS daemon has gone away.

  	 */

  	while (!kthread_should_stop()) {

  		long timeout = MAX_SCHEDULE_TIMEOUT;

  		RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);

  		/* update sv_maxconn if it has changed */
  		rqstp->rq_server->sv_maxconn = nlm_max_connections;

  		if (signalled()) {
  			flush_signals(current);

  			restart_grace();

  			continue;

  		}

  		timeout = nlmsvc_retry_blocked();

  		/*
  		 * Find a socket with data available and call its
  		 * recvfrom routine.
  		 */

  		err = svc_recv(rqstp, timeout);

  		if (err == -EAGAIN || err == -EINTR) {
  			preverr = err;

  			continue;

  		}

  		if (err < 0) {

  			if (err != preverr) {
  				printk(KERN_WARNING "%s: unexpected error "
  					"from svc_recv (%d)
  ", __func__, err);
  				preverr = err;
  			}
  			schedule_timeout_interruptible(HZ);
  			continue;

  		}

  		preverr = err;

  		dprintk("lockd: request from %s
  ",
  				svc_print_addr(rqstp, buf, sizeof(buf)));

  		svc_process(rqstp);

  	}

  	flush_signals(current);

  	cancel_delayed_work_sync(&grace_period_end);

  	locks_end_grace(&lockd_manager);

  	if (nlmsvc_ops)
  		nlmsvc_invalidate_all();
  	nlm_shutdown_hosts();

  	return 0;

  }

  static int create_lockd_listener(struct svc_serv *serv, const char *name,
  				 const int family, const unsigned short port)

  {
  	struct svc_xprt *xprt;

  	xprt = svc_find_xprt(serv, name, family, 0);

  	if (xprt == NULL)

  		return svc_create_xprt(serv, name, &init_net, family, port,

  						SVC_SOCK_DEFAULTS);

  	svc_xprt_put(xprt);
  	return 0;
  }

  static int create_lockd_family(struct svc_serv *serv, const int family)
  {
  	int err;
  
  	err = create_lockd_listener(serv, "udp", family, nlm_udpport);
  	if (err < 0)
  		return err;
  
  	return create_lockd_listener(serv, "tcp", family, nlm_tcpport);
  }

  /*

   * Ensure there are active UDP and TCP listeners for lockd.
   *
   * Even if we have only TCP NFS mounts and/or TCP NFSDs, some
   * local services (such as rpc.statd) still require UDP, and
   * some NFS servers do not yet support NLM over TCP.
   *
   * Returns zero if all listeners are available; otherwise a
   * negative errno value is returned.

   */

  static int make_socks(struct svc_serv *serv)

  {

  	static int warned;

  	int err;

  	err = create_lockd_family(serv, PF_INET);

  	if (err < 0)
  		goto out_err;

  	err = create_lockd_family(serv, PF_INET6);
  	if (err < 0 && err != -EAFNOSUPPORT)

  		goto out_err;
  
  	warned = 0;
  	return 0;
  
  out_err:
  	if (warned++ == 0)

  		printk(KERN_WARNING

  			"lockd_up: makesock failed, error=%d
  ", err);

  	return err;
  }

  /*
   * Bring up the lockd process if it's not already up.
   */

  int lockd_up(void)

  {

  	struct svc_serv *serv;

  	int		error = 0;

  	mutex_lock(&nlmsvc_mutex);

  	/*

  	 * Check whether we're already up and running.
  	 */

  	if (nlmsvc_rqst)

  		goto out;
  
  	/*
  	 * Sanity check: if there's no pid,
  	 * we should be the first user ...
  	 */

  	if (nlmsvc_users)

  		printk(KERN_WARNING
  			"lockd_up: no pid, %d users??
  ", nlmsvc_users);
  
  	error = -ENOMEM;

  	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);

  	if (!serv) {
  		printk(KERN_WARNING "lockd_up: create service failed
  ");
  		goto out;
  	}

  	error = make_socks(serv);
  	if (error < 0)

  		goto destroy_and_out;

  
  	/*
  	 * Create the kernel thread and wait for it to start.
  	 */

  	nlmsvc_rqst = svc_prepare_thread(serv, &serv->sv_pools[0], NUMA_NO_NODE);

  	if (IS_ERR(nlmsvc_rqst)) {
  		error = PTR_ERR(nlmsvc_rqst);
  		nlmsvc_rqst = NULL;

  		printk(KERN_WARNING
  			"lockd_up: svc_rqst allocation failed, error=%d
  ",
  			error);
  		goto destroy_and_out;
  	}
  
  	svc_sock_update_bufs(serv);

  	serv->sv_maxconn = nlm_max_connections;

  	nlmsvc_task = kthread_run(lockd, nlmsvc_rqst, serv->sv_name);

  	if (IS_ERR(nlmsvc_task)) {
  		error = PTR_ERR(nlmsvc_task);

  		svc_exit_thread(nlmsvc_rqst);

  		nlmsvc_task = NULL;

  		nlmsvc_rqst = NULL;

  		printk(KERN_WARNING

  			"lockd_up: kthread_run failed, error=%d
  ", error);

  		goto destroy_and_out;
  	}

  
  	/*
  	 * Note: svc_serv structures have an initial use count of 1,
  	 * so we exit through here on both success and failure.
  	 */
  destroy_and_out:
  	svc_destroy(serv);
  out:

  	if (!error)
  		nlmsvc_users++;

  	mutex_unlock(&nlmsvc_mutex);

  	return error;
  }

  EXPORT_SYMBOL_GPL(lockd_up);

  
  /*
   * Decrement the user count and bring down lockd if we're the last.
   */
  void
  lockd_down(void)
  {

  	mutex_lock(&nlmsvc_mutex);

  	if (nlmsvc_users) {
  		if (--nlmsvc_users)
  			goto out;

  	} else {
  		printk(KERN_ERR "lockd_down: no users! task=%p
  ",
  			nlmsvc_task);
  		BUG();

  	}

  	if (!nlmsvc_task) {
  		printk(KERN_ERR "lockd_down: no lockd running.
  ");
  		BUG();

  	}

  	kthread_stop(nlmsvc_task);

  	svc_exit_thread(nlmsvc_rqst);
  	nlmsvc_task = NULL;
  	nlmsvc_rqst = NULL;

  out:

  	mutex_unlock(&nlmsvc_mutex);

  }

  EXPORT_SYMBOL_GPL(lockd_down);

  #ifdef CONFIG_SYSCTL

  /*
   * Sysctl parameters (same as module parameters, different interface).
   */

  static ctl_table nlm_sysctls[] = {
  	{

  		.procname	= "nlm_grace_period",
  		.data		= &nlm_grace_period,

  		.maxlen		= sizeof(unsigned long),

  		.mode		= 0644,

  		.proc_handler	= proc_doulongvec_minmax,

  		.extra1		= (unsigned long *) &nlm_grace_period_min,
  		.extra2		= (unsigned long *) &nlm_grace_period_max,
  	},
  	{

  		.procname	= "nlm_timeout",
  		.data		= &nlm_timeout,

  		.maxlen		= sizeof(unsigned long),

  		.mode		= 0644,

  		.proc_handler	= proc_doulongvec_minmax,

  		.extra1		= (unsigned long *) &nlm_timeout_min,
  		.extra2		= (unsigned long *) &nlm_timeout_max,
  	},
  	{

  		.procname	= "nlm_udpport",
  		.data		= &nlm_udpport,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec_minmax,

  		.extra1		= (int *) &nlm_port_min,
  		.extra2		= (int *) &nlm_port_max,
  	},
  	{

  		.procname	= "nlm_tcpport",
  		.data		= &nlm_tcpport,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec_minmax,

  		.extra1		= (int *) &nlm_port_min,
  		.extra2		= (int *) &nlm_port_max,
  	},

  	{

  		.procname	= "nsm_use_hostnames",
  		.data		= &nsm_use_hostnames,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec,

  	},

  	{

  		.procname	= "nsm_local_state",
  		.data		= &nsm_local_state,
  		.maxlen		= sizeof(int),
  		.mode		= 0644,

  		.proc_handler	= proc_dointvec,

  	},

  	{ }

  };
  
  static ctl_table nlm_sysctl_dir[] = {
  	{

  		.procname	= "nfs",
  		.mode		= 0555,
  		.child		= nlm_sysctls,
  	},

  	{ }

  };
  
  static ctl_table nlm_sysctl_root[] = {
  	{

  		.procname	= "fs",
  		.mode		= 0555,
  		.child		= nlm_sysctl_dir,
  	},

  	{ }

  };

  #endif	/* CONFIG_SYSCTL */

  /*

   * Module (and sysfs) parameters.

   */
  
  #define param_set_min_max(name, type, which_strtol, min, max)		\
  static int param_set_##name(const char *val, struct kernel_param *kp)	\
  {									\
  	char *endp;							\
  	__typeof__(type) num = which_strtol(val, &endp, 0);		\
  	if (endp == val || *endp || num < (min) || num > (max))		\
  		return -EINVAL;						\
  	*((int *) kp->arg) = num;					\
  	return 0;							\
  }
  
  static inline int is_callback(u32 proc)
  {
  	return proc == NLMPROC_GRANTED
  		|| proc == NLMPROC_GRANTED_MSG
  		|| proc == NLMPROC_TEST_RES
  		|| proc == NLMPROC_LOCK_RES
  		|| proc == NLMPROC_CANCEL_RES
  		|| proc == NLMPROC_UNLOCK_RES
  		|| proc == NLMPROC_NSM_NOTIFY;
  }
  
  
  static int lockd_authenticate(struct svc_rqst *rqstp)
  {
  	rqstp->rq_client = NULL;
  	switch (rqstp->rq_authop->flavour) {
  		case RPC_AUTH_NULL:
  		case RPC_AUTH_UNIX:
  			if (rqstp->rq_proc == 0)
  				return SVC_OK;
  			if (is_callback(rqstp->rq_proc)) {
  				/* Leave it to individual procedures to
  				 * call nlmsvc_lookup_host(rqstp)
  				 */
  				return SVC_OK;
  			}
  			return svc_set_client(rqstp);
  	}
  	return SVC_DENIED;
  }
  
  
  param_set_min_max(port, int, simple_strtol, 0, 65535)
  param_set_min_max(grace_period, unsigned long, simple_strtoul,
  		  nlm_grace_period_min, nlm_grace_period_max)
  param_set_min_max(timeout, unsigned long, simple_strtoul,
  		  nlm_timeout_min, nlm_timeout_max)
  
  MODULE_AUTHOR("Olaf Kirch <okir@monad.swb.de>");
  MODULE_DESCRIPTION("NFS file locking service version " LOCKD_VERSION ".");
  MODULE_LICENSE("GPL");
  
  module_param_call(nlm_grace_period, param_set_grace_period, param_get_ulong,
  		  &nlm_grace_period, 0644);
  module_param_call(nlm_timeout, param_set_timeout, param_get_ulong,
  		  &nlm_timeout, 0644);
  module_param_call(nlm_udpport, param_set_port, param_get_int,
  		  &nlm_udpport, 0644);
  module_param_call(nlm_tcpport, param_set_port, param_get_int,
  		  &nlm_tcpport, 0644);

  module_param(nsm_use_hostnames, bool, 0644);

  module_param(nlm_max_connections, uint, 0644);

  
  /*
   * Initialising and terminating the module.
   */
  
  static int __init init_nlm(void)
  {

  #ifdef CONFIG_SYSCTL

  	nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);

  	return nlm_sysctl_table ? 0 : -ENOMEM;

  #else
  	return 0;
  #endif

  }
  
  static void __exit exit_nlm(void)
  {
  	/* FIXME: delete all NLM clients */
  	nlm_shutdown_hosts();

  #ifdef CONFIG_SYSCTL

  	unregister_sysctl_table(nlm_sysctl_table);

  #endif

  }
  
  module_init(init_nlm);
  module_exit(exit_nlm);
  
  /*
   * Define NLM program and procedures
   */
  static struct svc_version	nlmsvc_version1 = {
  		.vs_vers	= 1,
  		.vs_nproc	= 17,
  		.vs_proc	= nlmsvc_procedures,
  		.vs_xdrsize	= NLMSVC_XDRSIZE,
  };
  static struct svc_version	nlmsvc_version3 = {
  		.vs_vers	= 3,
  		.vs_nproc	= 24,
  		.vs_proc	= nlmsvc_procedures,
  		.vs_xdrsize	= NLMSVC_XDRSIZE,
  };
  #ifdef CONFIG_LOCKD_V4
  static struct svc_version	nlmsvc_version4 = {
  		.vs_vers	= 4,
  		.vs_nproc	= 24,
  		.vs_proc	= nlmsvc_procedures4,
  		.vs_xdrsize	= NLMSVC_XDRSIZE,
  };
  #endif
  static struct svc_version *	nlmsvc_version[] = {
  	[1] = &nlmsvc_version1,
  	[3] = &nlmsvc_version3,
  #ifdef CONFIG_LOCKD_V4
  	[4] = &nlmsvc_version4,
  #endif
  };
  
  static struct svc_stat		nlmsvc_stats;

  #define NLM_NRVERS	ARRAY_SIZE(nlmsvc_version)

  static struct svc_program	nlmsvc_program = {
  	.pg_prog		= NLM_PROGRAM,		/* program number */
  	.pg_nvers		= NLM_NRVERS,		/* number of entries in nlmsvc_version */
  	.pg_vers		= nlmsvc_version,	/* version table */
  	.pg_name		= "lockd",		/* service name */
  	.pg_class		= "nfsd",		/* share authentication with nfsd */
  	.pg_stats		= &nlmsvc_stats,	/* stats table */
  	.pg_authenticate = &lockd_authenticate	/* export authentication */
  };