ipvs: do not disable bh for long time

[mirror_ubuntu-zesty-kernel.git] / net / netfilter / ipvs / ip_vs_lblcr.c

/*
 * IPVS:        Locality-Based Least-Connection with Replication scheduler
 *
 * Authors:     Wensong Zhang <wensong@gnuchina.org>
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Changes:
 *     Julian Anastasov        :    Added the missing (dest->weight>0)
 *                                  condition in the ip_vs_dest_set_max.
 *
 */

/*
 * The lblc/r algorithm is as follows (pseudo code):
 *
 *       if serverSet[dest_ip] is null then
 *               n, serverSet[dest_ip] <- {weighted least-conn node};
 *       else
 *               n <- {least-conn (alive) node in serverSet[dest_ip]};
 *               if (n is null) OR
 *                  (n.conns>n.weight AND
 *                   there is a node m with m.conns<m.weight/2) then
 *                   n <- {weighted least-conn node};
 *                   add n to serverSet[dest_ip];
 *               if |serverSet[dest_ip]| > 1 AND
 *                   now - serverSet[dest_ip].lastMod > T then
 *                   m <- {most conn node in serverSet[dest_ip]};
 *                   remove m from serverSet[dest_ip];
 *       if serverSet[dest_ip] changed then
 *               serverSet[dest_ip].lastMod <- now;
 *
 *       return n;
 *
 */

#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/ip.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/jiffies.h>
#include <linux/list.h>
#include <linux/slab.h>

/* for sysctl */
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <net/net_namespace.h>

#include <net/ip_vs.h>


/*
 *    It is for garbage collection of stale IPVS lblcr entries,
 *    when the table is full.
 */
#define CHECK_EXPIRE_INTERVAL   (60*HZ)
#define ENTRY_TIMEOUT           (6*60*HZ)

#define DEFAULT_EXPIRATION      (24*60*60*HZ)

/*
 *    It is for full expiration check.
 *    When there is no partial expiration check (garbage collection)
 *    in a half hour, do a full expiration check to collect stale
 *    entries that haven't been touched for a day.
 */
#define COUNT_FOR_FULL_EXPIRATION   30

/*
 *     for IPVS lblcr entry hash table
 */
#ifndef CONFIG_IP_VS_LBLCR_TAB_BITS
#define CONFIG_IP_VS_LBLCR_TAB_BITS      10
#endif
#define IP_VS_LBLCR_TAB_BITS     CONFIG_IP_VS_LBLCR_TAB_BITS
#define IP_VS_LBLCR_TAB_SIZE     (1 << IP_VS_LBLCR_TAB_BITS)
#define IP_VS_LBLCR_TAB_MASK     (IP_VS_LBLCR_TAB_SIZE - 1)


/*
 *      IPVS destination set structure and operations
 */
struct ip_vs_dest_set_elem {
        struct list_head        list;          /* list link */
        struct ip_vs_dest __rcu *dest;         /* destination server */
        struct rcu_head         rcu_head;
};

struct ip_vs_dest_set {
        atomic_t                size;           /* set size */
        unsigned long           lastmod;        /* last modified time */
        struct list_head        list;           /* destination list */
};


static void ip_vs_dest_set_insert(struct ip_vs_dest_set *set,
                                  struct ip_vs_dest *dest, bool check)
{
        struct ip_vs_dest_set_elem *e;

        if (check) {
                list_for_each_entry(e, &set->list, list) {
                        struct ip_vs_dest *d;

                        d = rcu_dereference_protected(e->dest, 1);
                        if (d == dest)
                                /* already existed */
                                return;
                }
        }

        e = kmalloc(sizeof(*e), GFP_ATOMIC);
        if (e == NULL)
                return;

        ip_vs_dest_hold(dest);
        RCU_INIT_POINTER(e->dest, dest);

        list_add_rcu(&e->list, &set->list);
        atomic_inc(&set->size);

        set->lastmod = jiffies;
}

static void
ip_vs_dest_set_erase(struct ip_vs_dest_set *set, struct ip_vs_dest *dest)
{
        struct ip_vs_dest_set_elem *e;

        list_for_each_entry(e, &set->list, list) {
                struct ip_vs_dest *d;

                d = rcu_dereference_protected(e->dest, 1);
                if (d == dest) {
                        /* HIT */
                        atomic_dec(&set->size);
                        set->lastmod = jiffies;
                        ip_vs_dest_put(dest);
                        list_del_rcu(&e->list);
                        kfree_rcu(e, rcu_head);
                        break;
                }
        }
}

static void ip_vs_dest_set_eraseall(struct ip_vs_dest_set *set)
{
        struct ip_vs_dest_set_elem *e, *ep;

        list_for_each_entry_safe(e, ep, &set->list, list) {
                struct ip_vs_dest *d;

                d = rcu_dereference_protected(e->dest, 1);
                /*
                 * We don't kfree dest because it is referred either
                 * by its service or by the trash dest list.
                 */
                ip_vs_dest_put(d);
                list_del_rcu(&e->list);
                kfree_rcu(e, rcu_head);
        }
}

/* get weighted least-connection node in the destination set */
static inline struct ip_vs_dest *ip_vs_dest_set_min(struct ip_vs_dest_set *set)
{
        register struct ip_vs_dest_set_elem *e;
        struct ip_vs_dest *dest, *least;
        int loh, doh;

        if (set == NULL)
                return NULL;

        /* select the first destination server, whose weight > 0 */
        list_for_each_entry_rcu(e, &set->list, list) {
                least = rcu_dereference(e->dest);
                if (least->flags & IP_VS_DEST_F_OVERLOAD)
                        continue;

                if ((atomic_read(&least->weight) > 0)
                    && (least->flags & IP_VS_DEST_F_AVAILABLE)) {
                        loh = ip_vs_dest_conn_overhead(least);
                        goto nextstage;
                }
        }
        return NULL;

        /* find the destination with the weighted least load */
  nextstage:
        list_for_each_entry_continue_rcu(e, &set->list, list) {
                dest = rcu_dereference(e->dest);
                if (dest->flags & IP_VS_DEST_F_OVERLOAD)
                        continue;

                doh = ip_vs_dest_conn_overhead(dest);
                if ((loh * atomic_read(&dest->weight) >
                     doh * atomic_read(&least->weight))
                    && (dest->flags & IP_VS_DEST_F_AVAILABLE)) {
                        least = dest;
                        loh = doh;
                }
        }

        IP_VS_DBG_BUF(6, "%s(): server %s:%d "
                      "activeconns %d refcnt %d weight %d overhead %d\n",
                      __func__,
                      IP_VS_DBG_ADDR(least->af, &least->addr),
                      ntohs(least->port),
                      atomic_read(&least->activeconns),
                      atomic_read(&least->refcnt),
                      atomic_read(&least->weight), loh);
        return least;
}


/* get weighted most-connection node in the destination set */
static inline struct ip_vs_dest *ip_vs_dest_set_max(struct ip_vs_dest_set *set)
{
        register struct ip_vs_dest_set_elem *e;
        struct ip_vs_dest *dest, *most;
        int moh, doh;

        if (set == NULL)
                return NULL;

        /* select the first destination server, whose weight > 0 */
        list_for_each_entry(e, &set->list, list) {
                most = rcu_dereference_protected(e->dest, 1);
                if (atomic_read(&most->weight) > 0) {
                        moh = ip_vs_dest_conn_overhead(most);
                        goto nextstage;
                }
        }
        return NULL;

        /* find the destination with the weighted most load */
  nextstage:
        list_for_each_entry_continue(e, &set->list, list) {
                dest = rcu_dereference_protected(e->dest, 1);
                doh = ip_vs_dest_conn_overhead(dest);
                /* moh/mw < doh/dw ==> moh*dw < doh*mw, where mw,dw>0 */
                if ((moh * atomic_read(&dest->weight) <
                     doh * atomic_read(&most->weight))
                    && (atomic_read(&dest->weight) > 0)) {
                        most = dest;
                        moh = doh;
                }
        }

        IP_VS_DBG_BUF(6, "%s(): server %s:%d "
                      "activeconns %d refcnt %d weight %d overhead %d\n",
                      __func__,
                      IP_VS_DBG_ADDR(most->af, &most->addr), ntohs(most->port),
                      atomic_read(&most->activeconns),
                      atomic_read(&most->refcnt),
                      atomic_read(&most->weight), moh);
        return most;
}


/*
 *      IPVS lblcr entry represents an association between destination
 *      IP address and its destination server set
 */
struct ip_vs_lblcr_entry {
        struct hlist_node       list;
        int                     af;             /* address family */
        union nf_inet_addr      addr;           /* destination IP address */
        struct ip_vs_dest_set   set;            /* destination server set */
        unsigned long           lastuse;        /* last used time */
        struct rcu_head         rcu_head;
};


/*
 *      IPVS lblcr hash table
 */
struct ip_vs_lblcr_table {
        struct rcu_head         rcu_head;
        struct hlist_head __rcu bucket[IP_VS_LBLCR_TAB_SIZE];  /* hash bucket */
        atomic_t                entries;        /* number of entries */
        int                     max_size;       /* maximum size of entries */
        struct timer_list       periodic_timer; /* collect stale entries */
        int                     rover;          /* rover for expire check */
        int                     counter;        /* counter for no expire */
        bool                    dead;
};


#ifdef CONFIG_SYSCTL
/*
 *      IPVS LBLCR sysctl table
 */

static ctl_table vs_vars_table[] = {
        {
                .procname       = "lblcr_expiration",
                .data           = NULL,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        { }
};
#endif

static inline void ip_vs_lblcr_free(struct ip_vs_lblcr_entry *en)
{
        hlist_del_rcu(&en->list);
        ip_vs_dest_set_eraseall(&en->set);
        kfree_rcu(en, rcu_head);
}


/*
 *      Returns hash value for IPVS LBLCR entry
 */
static inline unsigned int
ip_vs_lblcr_hashkey(int af, const union nf_inet_addr *addr)
{
        __be32 addr_fold = addr->ip;

#ifdef CONFIG_IP_VS_IPV6
        if (af == AF_INET6)
                addr_fold = addr->ip6[0]^addr->ip6[1]^
                            addr->ip6[2]^addr->ip6[3];
#endif
        return (ntohl(addr_fold)*2654435761UL) & IP_VS_LBLCR_TAB_MASK;
}


/*
 *      Hash an entry in the ip_vs_lblcr_table.
 *      returns bool success.
 */
static void
ip_vs_lblcr_hash(struct ip_vs_lblcr_table *tbl, struct ip_vs_lblcr_entry *en)
{
        unsigned int hash = ip_vs_lblcr_hashkey(en->af, &en->addr);

        hlist_add_head_rcu(&en->list, &tbl->bucket[hash]);
        atomic_inc(&tbl->entries);
}


/* Get ip_vs_lblcr_entry associated with supplied parameters. */
static inline struct ip_vs_lblcr_entry *
ip_vs_lblcr_get(int af, struct ip_vs_lblcr_table *tbl,
                const union nf_inet_addr *addr)
{
        unsigned int hash = ip_vs_lblcr_hashkey(af, addr);
        struct ip_vs_lblcr_entry *en;

        hlist_for_each_entry_rcu(en, &tbl->bucket[hash], list)
                if (ip_vs_addr_equal(af, &en->addr, addr))
                        return en;

        return NULL;
}


/*
 * Create or update an ip_vs_lblcr_entry, which is a mapping of a destination
 * IP address to a server. Called under spin lock.
 */
static inline struct ip_vs_lblcr_entry *
ip_vs_lblcr_new(struct ip_vs_lblcr_table *tbl, const union nf_inet_addr *daddr,
                struct ip_vs_dest *dest)
{
        struct ip_vs_lblcr_entry *en;

        en = ip_vs_lblcr_get(dest->af, tbl, daddr);
        if (!en) {
                en = kmalloc(sizeof(*en), GFP_ATOMIC);
                if (!en)
                        return NULL;

                en->af = dest->af;
                ip_vs_addr_copy(dest->af, &en->addr, daddr);
                en->lastuse = jiffies;

                /* initialize its dest set */
                atomic_set(&(en->set.size), 0);
                INIT_LIST_HEAD(&en->set.list);

                ip_vs_dest_set_insert(&en->set, dest, false);

                ip_vs_lblcr_hash(tbl, en);
                return en;
        }

        ip_vs_dest_set_insert(&en->set, dest, true);

        return en;
}


/*
 *      Flush all the entries of the specified table.
 */
static void ip_vs_lblcr_flush(struct ip_vs_service *svc)
{
        struct ip_vs_lblcr_table *tbl = svc->sched_data;
        int i;
        struct ip_vs_lblcr_entry *en;
        struct hlist_node *next;

        spin_lock_bh(&svc->sched_lock);
        tbl->dead = 1;
        for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
                hlist_for_each_entry_safe(en, next, &tbl->bucket[i], list) {
                        ip_vs_lblcr_free(en);
                }
        }
        spin_unlock_bh(&svc->sched_lock);
}

static int sysctl_lblcr_expiration(struct ip_vs_service *svc)
{
#ifdef CONFIG_SYSCTL
        struct netns_ipvs *ipvs = net_ipvs(svc->net);
        return ipvs->sysctl_lblcr_expiration;
#else
        return DEFAULT_EXPIRATION;
#endif
}

static inline void ip_vs_lblcr_full_check(struct ip_vs_service *svc)
{
        struct ip_vs_lblcr_table *tbl = svc->sched_data;
        unsigned long now = jiffies;
        int i, j;
        struct ip_vs_lblcr_entry *en;
        struct hlist_node *next;

        for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
                j = (j + 1) & IP_VS_LBLCR_TAB_MASK;

                spin_lock(&svc->sched_lock);
                hlist_for_each_entry_safe(en, next, &tbl->bucket[j], list) {
                        if (time_after(en->lastuse +
                                       sysctl_lblcr_expiration(svc), now))
                                continue;

                        ip_vs_lblcr_free(en);
                        atomic_dec(&tbl->entries);
                }
                spin_unlock(&svc->sched_lock);
        }
        tbl->rover = j;
}


/*
 *      Periodical timer handler for IPVS lblcr table
 *      It is used to collect stale entries when the number of entries
 *      exceeds the maximum size of the table.
 *
 *      Fixme: we probably need more complicated algorithm to collect
 *             entries that have not been used for a long time even
 *             if the number of entries doesn't exceed the maximum size
 *             of the table.
 *      The full expiration check is for this purpose now.
 */
static void ip_vs_lblcr_check_expire(unsigned long data)
{
        struct ip_vs_service *svc = (struct ip_vs_service *) data;
        struct ip_vs_lblcr_table *tbl = svc->sched_data;
        unsigned long now = jiffies;
        int goal;
        int i, j;
        struct ip_vs_lblcr_entry *en;
        struct hlist_node *next;

        if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
                /* do full expiration check */
                ip_vs_lblcr_full_check(svc);
                tbl->counter = 1;
                goto out;
        }

        if (atomic_read(&tbl->entries) <= tbl->max_size) {
                tbl->counter++;
                goto out;
        }

        goal = (atomic_read(&tbl->entries) - tbl->max_size)*4/3;
        if (goal > tbl->max_size/2)
                goal = tbl->max_size/2;

        for (i=0, j=tbl->rover; i<IP_VS_LBLCR_TAB_SIZE; i++) {
                j = (j + 1) & IP_VS_LBLCR_TAB_MASK;

                spin_lock(&svc->sched_lock);
                hlist_for_each_entry_safe(en, next, &tbl->bucket[j], list) {
                        if (time_before(now, en->lastuse+ENTRY_TIMEOUT))
                                continue;

                        ip_vs_lblcr_free(en);
                        atomic_dec(&tbl->entries);
                        goal--;
                }
                spin_unlock(&svc->sched_lock);
                if (goal <= 0)
                        break;
        }
        tbl->rover = j;

  out:
        mod_timer(&tbl->periodic_timer, jiffies+CHECK_EXPIRE_INTERVAL);
}

static int ip_vs_lblcr_init_svc(struct ip_vs_service *svc)
{
        int i;
        struct ip_vs_lblcr_table *tbl;

        /*
         *    Allocate the ip_vs_lblcr_table for this service
         */
        tbl = kmalloc(sizeof(*tbl), GFP_KERNEL);
        if (tbl == NULL)
                return -ENOMEM;

        svc->sched_data = tbl;
        IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) allocated for "
                  "current service\n", sizeof(*tbl));

        /*
         *    Initialize the hash buckets
         */
        for (i=0; i<IP_VS_LBLCR_TAB_SIZE; i++) {
                INIT_HLIST_HEAD(&tbl->bucket[i]);
        }
        tbl->max_size = IP_VS_LBLCR_TAB_SIZE*16;
        tbl->rover = 0;
        tbl->counter = 1;
        tbl->dead = 0;

        /*
         *    Hook periodic timer for garbage collection
         */
        setup_timer(&tbl->periodic_timer, ip_vs_lblcr_check_expire,
                        (unsigned long)svc);
        mod_timer(&tbl->periodic_timer, jiffies + CHECK_EXPIRE_INTERVAL);

        return 0;
}


static void ip_vs_lblcr_done_svc(struct ip_vs_service *svc)
{
        struct ip_vs_lblcr_table *tbl = svc->sched_data;

        /* remove periodic timer */
        del_timer_sync(&tbl->periodic_timer);

        /* got to clean up table entries here */
        ip_vs_lblcr_flush(svc);

        /* release the table itself */
        kfree_rcu(tbl, rcu_head);
        IP_VS_DBG(6, "LBLCR hash table (memory=%Zdbytes) released\n",
                  sizeof(*tbl));
}


static inline struct ip_vs_dest *
__ip_vs_lblcr_schedule(struct ip_vs_service *svc)
{
        struct ip_vs_dest *dest, *least;
        int loh, doh;

        /*
         * We use the following formula to estimate the load:
         *                (dest overhead) / dest->weight
         *
         * Remember -- no floats in kernel mode!!!
         * The comparison of h1*w2 > h2*w1 is equivalent to that of
         *                h1/w1 > h2/w2
         * if every weight is larger than zero.
         *
         * The server with weight=0 is quiesced and will not receive any
         * new connection.
         */
        list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
                if (dest->flags & IP_VS_DEST_F_OVERLOAD)
                        continue;

                if (atomic_read(&dest->weight) > 0) {
                        least = dest;
                        loh = ip_vs_dest_conn_overhead(least);
                        goto nextstage;
                }
        }
        return NULL;

        /*
         *    Find the destination with the least load.
         */
  nextstage:
        list_for_each_entry_continue_rcu(dest, &svc->destinations, n_list) {
                if (dest->flags & IP_VS_DEST_F_OVERLOAD)
                        continue;

                doh = ip_vs_dest_conn_overhead(dest);
                if (loh * atomic_read(&dest->weight) >
                    doh * atomic_read(&least->weight)) {
                        least = dest;
                        loh = doh;
                }
        }

        IP_VS_DBG_BUF(6, "LBLCR: server %s:%d "
                      "activeconns %d refcnt %d weight %d overhead %d\n",
                      IP_VS_DBG_ADDR(least->af, &least->addr),
                      ntohs(least->port),
                      atomic_read(&least->activeconns),
                      atomic_read(&least->refcnt),
                      atomic_read(&least->weight), loh);

        return least;
}


/*
 *   If this destination server is overloaded and there is a less loaded
 *   server, then return true.
 */
static inline int
is_overloaded(struct ip_vs_dest *dest, struct ip_vs_service *svc)
{
        if (atomic_read(&dest->activeconns) > atomic_read(&dest->weight)) {
                struct ip_vs_dest *d;

                list_for_each_entry_rcu(d, &svc->destinations, n_list) {
                        if (atomic_read(&d->activeconns)*2
                            < atomic_read(&d->weight)) {
                                return 1;
                        }
                }
        }
        return 0;
}


/*
 *    Locality-Based (weighted) Least-Connection scheduling
 */
static struct ip_vs_dest *
ip_vs_lblcr_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
{
        struct ip_vs_lblcr_table *tbl = svc->sched_data;
        struct ip_vs_iphdr iph;
        struct ip_vs_dest *dest;
        struct ip_vs_lblcr_entry *en;

        ip_vs_fill_iph_addr_only(svc->af, skb, &iph);

        IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);

        /* First look in our cache */
        en = ip_vs_lblcr_get(svc->af, tbl, &iph.daddr);
        if (en) {
                en->lastuse = jiffies;

                /* Get the least loaded destination */
                dest = ip_vs_dest_set_min(&en->set);

                /* More than one destination + enough time passed by, cleanup */
                if (atomic_read(&en->set.size) > 1 &&
                    time_after(jiffies, en->set.lastmod +
                                sysctl_lblcr_expiration(svc))) {
                        spin_lock_bh(&svc->sched_lock);
                        if (atomic_read(&en->set.size) > 1) {
                                struct ip_vs_dest *m;

                                m = ip_vs_dest_set_max(&en->set);
                                if (m)
                                        ip_vs_dest_set_erase(&en->set, m);
                        }
                        spin_unlock_bh(&svc->sched_lock);
                }

                /* If the destination is not overloaded, use it */
                if (dest && !is_overloaded(dest, svc))
                        goto out;

                /* The cache entry is invalid, time to schedule */
                dest = __ip_vs_lblcr_schedule(svc);
                if (!dest) {
                        ip_vs_scheduler_err(svc, "no destination available");
                        return NULL;
                }

                /* Update our cache entry */
                spin_lock_bh(&svc->sched_lock);
                if (!tbl->dead)
                        ip_vs_dest_set_insert(&en->set, dest, true);
                spin_unlock_bh(&svc->sched_lock);
                goto out;
        }

        /* No cache entry, time to schedule */
        dest = __ip_vs_lblcr_schedule(svc);
        if (!dest) {
                IP_VS_DBG(1, "no destination available\n");
                return NULL;
        }

        /* If we fail to create a cache entry, we'll just use the valid dest */
        spin_lock_bh(&svc->sched_lock);
        if (!tbl->dead)
                ip_vs_lblcr_new(tbl, &iph.daddr, dest);
        spin_unlock_bh(&svc->sched_lock);

out:
        IP_VS_DBG_BUF(6, "LBLCR: destination IP address %s --> server %s:%d\n",
                      IP_VS_DBG_ADDR(svc->af, &iph.daddr),
                      IP_VS_DBG_ADDR(svc->af, &dest->addr), ntohs(dest->port));

        return dest;
}


/*
 *      IPVS LBLCR Scheduler structure
 */
static struct ip_vs_scheduler ip_vs_lblcr_scheduler =
{
        .name =                 "lblcr",
        .refcnt =               ATOMIC_INIT(0),
        .module =               THIS_MODULE,
        .n_list =               LIST_HEAD_INIT(ip_vs_lblcr_scheduler.n_list),
        .init_service =         ip_vs_lblcr_init_svc,
        .done_service =         ip_vs_lblcr_done_svc,
        .schedule =             ip_vs_lblcr_schedule,
};

/*
 *  per netns init.
 */
#ifdef CONFIG_SYSCTL
static int __net_init __ip_vs_lblcr_init(struct net *net)
{
        struct netns_ipvs *ipvs = net_ipvs(net);

        if (!ipvs)
                return -ENOENT;

        if (!net_eq(net, &init_net)) {
                ipvs->lblcr_ctl_table = kmemdup(vs_vars_table,
                                                sizeof(vs_vars_table),
                                                GFP_KERNEL);
                if (ipvs->lblcr_ctl_table == NULL)
                        return -ENOMEM;

                /* Don't export sysctls to unprivileged users */
                if (net->user_ns != &init_user_ns)
                        ipvs->lblcr_ctl_table[0].procname = NULL;
        } else
                ipvs->lblcr_ctl_table = vs_vars_table;
        ipvs->sysctl_lblcr_expiration = DEFAULT_EXPIRATION;
        ipvs->lblcr_ctl_table[0].data = &ipvs->sysctl_lblcr_expiration;

        ipvs->lblcr_ctl_header =
                register_net_sysctl(net, "net/ipv4/vs", ipvs->lblcr_ctl_table);
        if (!ipvs->lblcr_ctl_header) {
                if (!net_eq(net, &init_net))
                        kfree(ipvs->lblcr_ctl_table);
                return -ENOMEM;
        }

        return 0;
}

static void __net_exit __ip_vs_lblcr_exit(struct net *net)
{
        struct netns_ipvs *ipvs = net_ipvs(net);

        unregister_net_sysctl_table(ipvs->lblcr_ctl_header);

        if (!net_eq(net, &init_net))
                kfree(ipvs->lblcr_ctl_table);
}

#else

static int __net_init __ip_vs_lblcr_init(struct net *net) { return 0; }
static void __net_exit __ip_vs_lblcr_exit(struct net *net) { }

#endif

static struct pernet_operations ip_vs_lblcr_ops = {
        .init = __ip_vs_lblcr_init,
        .exit = __ip_vs_lblcr_exit,
};

static int __init ip_vs_lblcr_init(void)
{
        int ret;

        ret = register_pernet_subsys(&ip_vs_lblcr_ops);
        if (ret)
                return ret;

        ret = register_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
        if (ret)
                unregister_pernet_subsys(&ip_vs_lblcr_ops);
        return ret;
}

static void __exit ip_vs_lblcr_cleanup(void)
{
        unregister_ip_vs_scheduler(&ip_vs_lblcr_scheduler);
        unregister_pernet_subsys(&ip_vs_lblcr_ops);
        synchronize_rcu();
}


module_init(ip_vs_lblcr_init);
module_exit(ip_vs_lblcr_cleanup);
MODULE_LICENSE("GPL");