svc.c

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/*
 * 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 ([email protected])
 *
 * Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
 */

#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>

#include "netns.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;

int lockd_net_id;

/*
 * 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 void grace_ender(struct work_struct *grace)
{
    struct delayed_work *dwork = container_of(grace, struct delayed_work,
                          work);
    struct lockd_net *ln = container_of(dwork, struct lockd_net,
                        grace_period_end);

    locks_end_grace(&ln->lockd_manager);
}

static void set_grace_period(struct net *net)
{
    unsigned long grace_period = get_lockd_grace_period();
    struct lockd_net *ln = net_generic(net, lockd_net_id);

    locks_start_grace(net, &ln->lockd_manager);
    cancel_delayed_work_sync(&ln->grace_period_end);
    schedule_delayed_work(&ln->grace_period_end, grace_period);
}

static void restart_grace(void)
{
    if (nlmsvc_ops) {
        struct net *net = &init_net;
        struct lockd_net *ln = net_generic(net, lockd_net_id);

        cancel_delayed_work_sync(&ln->grace_period_end);
        locks_end_grace(&ln->lockd_manager);
        nlmsvc_invalidate_all();
        set_grace_period(net);
    }
}

/*
 * This is the lockd kernel thread
 */
static int
lockd(void *vrqstp)
{
    int     err = 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 ").\n");

    if (!nlm_timeout)
        nlm_timeout = LOCKD_DFLT_TIMEO;
    nlmsvc_timeout = nlm_timeout * HZ;

    /*
     * 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)
            continue;
        dprintk("lockd: request from %s\n",
                svc_print_addr(rqstp, buf, sizeof(buf)));

        svc_process(rqstp);
    }
    flush_signals(current);
    if (nlmsvc_ops)
        nlmsvc_invalidate_all();
    nlm_shutdown_hosts();
    return 0;
}

static int create_lockd_listener(struct svc_serv *serv, const char *name,
                 struct net *net, const int family,
                 const unsigned short port)
{
    struct svc_xprt *xprt;

    xprt = svc_find_xprt(serv, name, net, family, 0);
    if (xprt == NULL)
        return svc_create_xprt(serv, name, net, family, port,
                        SVC_SOCK_DEFAULTS);
    svc_xprt_put(xprt);
    return 0;
}

static int create_lockd_family(struct svc_serv *serv, struct net *net,
                   const int family)
{
    int err;

    err = create_lockd_listener(serv, "udp", net, family, nlm_udpport);
    if (err < 0)
        return err;

    return create_lockd_listener(serv, "tcp", net, 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, struct net *net)
{
    static int warned;
    int err;

    err = create_lockd_family(serv, net, PF_INET);
    if (err < 0)
        goto out_err;

    err = create_lockd_family(serv, net, 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\n", err);
    return err;
}

static int lockd_up_net(struct svc_serv *serv, struct net *net)
{
    struct lockd_net *ln = net_generic(net, lockd_net_id);
    int error;

    if (ln->nlmsvc_users++)
        return 0;

    error = svc_bind(serv, net);
    if (error)
        goto err_bind;

    error = make_socks(serv, net);
    if (error < 0)
        goto err_socks;
    set_grace_period(net);
    dprintk("lockd_up_net: per-net data created; net=%p\n", net);
    return 0;

err_socks:
    svc_rpcb_cleanup(serv, net);
err_bind:
    ln->nlmsvc_users--;
    return error;
}

static void lockd_down_net(struct svc_serv *serv, struct net *net)
{
    struct lockd_net *ln = net_generic(net, lockd_net_id);

    if (ln->nlmsvc_users) {
        if (--ln->nlmsvc_users == 0) {
            nlm_shutdown_hosts_net(net);
            cancel_delayed_work_sync(&ln->grace_period_end);
            locks_end_grace(&ln->lockd_manager);
            svc_shutdown_net(serv, net);
            dprintk("lockd_down_net: per-net data destroyed; net=%p\n", net);
        }
    } else {
        printk(KERN_ERR "lockd_down_net: no users! task=%p, net=%p\n",
                nlmsvc_task, net);
        BUG();
    }
}

static int lockd_start_svc(struct svc_serv *serv)
{
    int error;

    if (nlmsvc_rqst)
        return 0;

    /*
     * 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);
        printk(KERN_WARNING
            "lockd_up: svc_rqst allocation failed, error=%d\n",
            error);
        goto out_rqst;
    }

    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);
        printk(KERN_WARNING
            "lockd_up: kthread_run failed, error=%d\n", error);
        goto out_task;
    }
    dprintk("lockd_up: service started\n");
    return 0;

out_task:
    svc_exit_thread(nlmsvc_rqst);
    nlmsvc_task = NULL;
out_rqst:
    nlmsvc_rqst = NULL;
    return error;
}

static struct svc_serv *lockd_create_svc(void)
{
    struct svc_serv *serv;

    /*
     * Check whether we're already up and running.
     */
    if (nlmsvc_rqst) {
        /*
         * Note: increase service usage, because later in case of error
         * svc_destroy() will be called.
         */
        svc_get(nlmsvc_rqst->rq_server);
        return nlmsvc_rqst->rq_server;
    }

    /*
     * 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??\n", nlmsvc_users);

    serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
    if (!serv) {
        printk(KERN_WARNING "lockd_up: create service failed\n");
        return ERR_PTR(-ENOMEM);
    }
    dprintk("lockd_up: service created\n");
    return serv;
}

/*
 * Bring up the lockd process if it's not already up.
 */
int lockd_up(struct net *net)
{
    struct svc_serv *serv;
    int error;

    mutex_lock(&nlmsvc_mutex);

    serv = lockd_create_svc();
    if (IS_ERR(serv)) {
        error = PTR_ERR(serv);
        goto err_create;
    }

    error = lockd_up_net(serv, net);
    if (error < 0)
        goto err_net;

    error = lockd_start_svc(serv);
    if (error < 0)
        goto err_start;

    nlmsvc_users++;
    /*
     * Note: svc_serv structures have an initial use count of 1,
     * so we exit through here on both success and failure.
     */
err_net:
    svc_destroy(serv);
err_create:
    mutex_unlock(&nlmsvc_mutex);
    return error;

err_start:
    lockd_down_net(serv, net);
    goto err_net;
}
EXPORT_SYMBOL_GPL(lockd_up);

/*
 * Decrement the user count and bring down lockd if we're the last.
 */
void
lockd_down(struct net *net)
{
    mutex_lock(&nlmsvc_mutex);
    lockd_down_net(nlmsvc_rqst->rq_server, net);
    if (nlmsvc_users) {
        if (--nlmsvc_users)
            goto out;
    } else {
        printk(KERN_ERR "lockd_down: no users! task=%p\n",
            nlmsvc_task);
        BUG();
    }

    if (!nlmsvc_task) {
        printk(KERN_ERR "lockd_down: no lockd running.\n");
        BUG();
    }
    kthread_stop(nlmsvc_task);
    dprintk("lockd_down: service stopped\n");
    svc_exit_thread(nlmsvc_rqst);
    dprintk("lockd_down: service destroyed\n");
    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;                     \
    *((type *) 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 <[email protected]>");
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);

static int lockd_init_net(struct net *net)
{
    struct lockd_net *ln = net_generic(net, lockd_net_id);

    INIT_DELAYED_WORK(&ln->grace_period_end, grace_ender);
    INIT_LIST_HEAD(&ln->grace_list);
    spin_lock_init(&ln->nsm_clnt_lock);
    return 0;
}

static void lockd_exit_net(struct net *net)
{
}

static struct pernet_operations lockd_net_ops = {
    .init = lockd_init_net,
    .exit = lockd_exit_net,
    .id = &lockd_net_id,
    .size = sizeof(struct lockd_net),
};


/*
 * Initialising and terminating the module.
 */

static int __init init_nlm(void)
{
    int err;

#ifdef CONFIG_SYSCTL
    err = -ENOMEM;
    nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
    if (nlm_sysctl_table == NULL)
        goto err_sysctl;
#endif
    err = register_pernet_subsys(&lockd_net_ops);
    if (err)
        goto err_pernet;
    return 0;

err_pernet:
#ifdef CONFIG_SYSCTL
    unregister_sysctl_table(nlm_sysctl_table);
#endif
err_sysctl:
    return err;
}

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