summaryrefslogtreecommitdiff
path: root/net/netfilter/ipvs/ip_vs_lblc.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_lblc.c')
-rw-r--r--net/netfilter/ipvs/ip_vs_lblc.c633
1 files changed, 633 insertions, 0 deletions
diff --git a/net/netfilter/ipvs/ip_vs_lblc.c b/net/netfilter/ipvs/ip_vs_lblc.c
new file mode 100644
index 000000000..127f14046
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_lblc.c
@@ -0,0 +1,633 @@
+/*
+ * IPVS: Locality-Based Least-Connection scheduling module
+ *
+ * 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:
+ * Martin Hamilton : fixed the terrible locking bugs
+ * *lock(tbl->lock) ==> *lock(&tbl->lock)
+ * Wensong Zhang : fixed the uninitialized tbl->lock bug
+ * Wensong Zhang : added doing full expiration check to
+ * collect stale entries of 24+ hours when
+ * no partial expire check in a half hour
+ * Julian Anastasov : replaced del_timer call with del_timer_sync
+ * to avoid the possible race between timer
+ * handler and del_timer thread in SMP
+ *
+ */
+
+/*
+ * The lblc algorithm is as follows (pseudo code):
+ *
+ * if cachenode[dest_ip] is null then
+ * n, cachenode[dest_ip] <- {weighted least-conn node};
+ * else
+ * n <- cachenode[dest_ip];
+ * if (n is dead) OR
+ * (n.conns>n.weight AND
+ * there is a node m with m.conns<m.weight/2) then
+ * n, cachenode[dest_ip] <- {weighted least-conn node};
+ *
+ * return n;
+ *
+ * Thanks must go to Wenzhuo Zhang for talking WCCP to me and pushing
+ * me to write this module.
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/ip.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/jiffies.h>
+
+/* for sysctl */
+#include <linux/fs.h>
+#include <linux/sysctl.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ * It is for garbage collection of stale IPVS lblc 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 lblc entry hash table
+ */
+#ifndef CONFIG_IP_VS_LBLC_TAB_BITS
+#define CONFIG_IP_VS_LBLC_TAB_BITS 10
+#endif
+#define IP_VS_LBLC_TAB_BITS CONFIG_IP_VS_LBLC_TAB_BITS
+#define IP_VS_LBLC_TAB_SIZE (1 << IP_VS_LBLC_TAB_BITS)
+#define IP_VS_LBLC_TAB_MASK (IP_VS_LBLC_TAB_SIZE - 1)
+
+
+/*
+ * IPVS lblc entry represents an association between destination
+ * IP address and its destination server
+ */
+struct ip_vs_lblc_entry {
+ struct hlist_node list;
+ int af; /* address family */
+ union nf_inet_addr addr; /* destination IP address */
+ struct ip_vs_dest *dest; /* real server (cache) */
+ unsigned long lastuse; /* last used time */
+ struct rcu_head rcu_head;
+};
+
+
+/*
+ * IPVS lblc hash table
+ */
+struct ip_vs_lblc_table {
+ struct rcu_head rcu_head;
+ struct hlist_head bucket[IP_VS_LBLC_TAB_SIZE]; /* hash bucket */
+ struct timer_list periodic_timer; /* collect stale entries */
+ atomic_t entries; /* number of entries */
+ int max_size; /* maximum size of entries */
+ int rover; /* rover for expire check */
+ int counter; /* counter for no expire */
+ bool dead;
+};
+
+
+/*
+ * IPVS LBLC sysctl table
+ */
+#ifdef CONFIG_SYSCTL
+static struct ctl_table vs_vars_table[] = {
+ {
+ .procname = "lblc_expiration",
+ .data = NULL,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec_jiffies,
+ },
+ { }
+};
+#endif
+
+static void ip_vs_lblc_rcu_free(struct rcu_head *head)
+{
+ struct ip_vs_lblc_entry *en = container_of(head,
+ struct ip_vs_lblc_entry,
+ rcu_head);
+
+ ip_vs_dest_put_and_free(en->dest);
+ kfree(en);
+}
+
+static inline void ip_vs_lblc_del(struct ip_vs_lblc_entry *en)
+{
+ hlist_del_rcu(&en->list);
+ call_rcu(&en->rcu_head, ip_vs_lblc_rcu_free);
+}
+
+/*
+ * Returns hash value for IPVS LBLC entry
+ */
+static inline unsigned int
+ip_vs_lblc_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_LBLC_TAB_MASK;
+}
+
+
+/*
+ * Hash an entry in the ip_vs_lblc_table.
+ * returns bool success.
+ */
+static void
+ip_vs_lblc_hash(struct ip_vs_lblc_table *tbl, struct ip_vs_lblc_entry *en)
+{
+ unsigned int hash = ip_vs_lblc_hashkey(en->af, &en->addr);
+
+ hlist_add_head_rcu(&en->list, &tbl->bucket[hash]);
+ atomic_inc(&tbl->entries);
+}
+
+
+/* Get ip_vs_lblc_entry associated with supplied parameters. */
+static inline struct ip_vs_lblc_entry *
+ip_vs_lblc_get(int af, struct ip_vs_lblc_table *tbl,
+ const union nf_inet_addr *addr)
+{
+ unsigned int hash = ip_vs_lblc_hashkey(af, addr);
+ struct ip_vs_lblc_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_lblc_entry, which is a mapping of a destination IP
+ * address to a server. Called under spin lock.
+ */
+static inline struct ip_vs_lblc_entry *
+ip_vs_lblc_new(struct ip_vs_lblc_table *tbl, const union nf_inet_addr *daddr,
+ u16 af, struct ip_vs_dest *dest)
+{
+ struct ip_vs_lblc_entry *en;
+
+ en = ip_vs_lblc_get(af, tbl, daddr);
+ if (en) {
+ if (en->dest == dest)
+ return en;
+ ip_vs_lblc_del(en);
+ }
+ en = kmalloc(sizeof(*en), GFP_ATOMIC);
+ if (!en)
+ return NULL;
+
+ en->af = af;
+ ip_vs_addr_copy(af, &en->addr, daddr);
+ en->lastuse = jiffies;
+
+ ip_vs_dest_hold(dest);
+ en->dest = dest;
+
+ ip_vs_lblc_hash(tbl, en);
+
+ return en;
+}
+
+
+/*
+ * Flush all the entries of the specified table.
+ */
+static void ip_vs_lblc_flush(struct ip_vs_service *svc)
+{
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+ struct ip_vs_lblc_entry *en;
+ struct hlist_node *next;
+ int i;
+
+ spin_lock_bh(&svc->sched_lock);
+ tbl->dead = 1;
+ for (i = 0; i < IP_VS_LBLC_TAB_SIZE; i++) {
+ hlist_for_each_entry_safe(en, next, &tbl->bucket[i], list) {
+ ip_vs_lblc_del(en);
+ atomic_dec(&tbl->entries);
+ }
+ }
+ spin_unlock_bh(&svc->sched_lock);
+}
+
+static int sysctl_lblc_expiration(struct ip_vs_service *svc)
+{
+#ifdef CONFIG_SYSCTL
+ struct netns_ipvs *ipvs = net_ipvs(svc->net);
+ return ipvs->sysctl_lblc_expiration;
+#else
+ return DEFAULT_EXPIRATION;
+#endif
+}
+
+static inline void ip_vs_lblc_full_check(struct ip_vs_service *svc)
+{
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+ struct ip_vs_lblc_entry *en;
+ struct hlist_node *next;
+ unsigned long now = jiffies;
+ int i, j;
+
+ for (i = 0, j = tbl->rover; i < IP_VS_LBLC_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLC_TAB_MASK;
+
+ spin_lock(&svc->sched_lock);
+ hlist_for_each_entry_safe(en, next, &tbl->bucket[j], list) {
+ if (time_before(now,
+ en->lastuse +
+ sysctl_lblc_expiration(svc)))
+ continue;
+
+ ip_vs_lblc_del(en);
+ atomic_dec(&tbl->entries);
+ }
+ spin_unlock(&svc->sched_lock);
+ }
+ tbl->rover = j;
+}
+
+
+/*
+ * Periodical timer handler for IPVS lblc 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_lblc_check_expire(unsigned long data)
+{
+ struct ip_vs_service *svc = (struct ip_vs_service *) data;
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+ unsigned long now = jiffies;
+ int goal;
+ int i, j;
+ struct ip_vs_lblc_entry *en;
+ struct hlist_node *next;
+
+ if ((tbl->counter % COUNT_FOR_FULL_EXPIRATION) == 0) {
+ /* do full expiration check */
+ ip_vs_lblc_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_LBLC_TAB_SIZE; i++) {
+ j = (j + 1) & IP_VS_LBLC_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_lblc_del(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_lblc_init_svc(struct ip_vs_service *svc)
+{
+ int i;
+ struct ip_vs_lblc_table *tbl;
+
+ /*
+ * Allocate the ip_vs_lblc_table for this service
+ */
+ tbl = kmalloc(sizeof(*tbl), GFP_KERNEL);
+ if (tbl == NULL)
+ return -ENOMEM;
+
+ svc->sched_data = tbl;
+ IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) allocated for "
+ "current service\n", sizeof(*tbl));
+
+ /*
+ * Initialize the hash buckets
+ */
+ for (i = 0; i < IP_VS_LBLC_TAB_SIZE; i++) {
+ INIT_HLIST_HEAD(&tbl->bucket[i]);
+ }
+ tbl->max_size = IP_VS_LBLC_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_lblc_check_expire,
+ (unsigned long)svc);
+ mod_timer(&tbl->periodic_timer, jiffies + CHECK_EXPIRE_INTERVAL);
+
+ return 0;
+}
+
+
+static void ip_vs_lblc_done_svc(struct ip_vs_service *svc)
+{
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+
+ /* remove periodic timer */
+ del_timer_sync(&tbl->periodic_timer);
+
+ /* got to clean up table entries here */
+ ip_vs_lblc_flush(svc);
+
+ /* release the table itself */
+ kfree_rcu(tbl, rcu_head);
+ IP_VS_DBG(6, "LBLC hash table (memory=%Zdbytes) released\n",
+ sizeof(*tbl));
+}
+
+
+static inline struct ip_vs_dest *
+__ip_vs_lblc_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 ((__s64)loh * atomic_read(&dest->weight) >
+ (__s64)doh * atomic_read(&least->weight)) {
+ least = dest;
+ loh = doh;
+ }
+ }
+
+ IP_VS_DBG_BUF(6, "LBLC: 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_lblc_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
+ struct ip_vs_iphdr *iph)
+{
+ struct ip_vs_lblc_table *tbl = svc->sched_data;
+ struct ip_vs_dest *dest = NULL;
+ struct ip_vs_lblc_entry *en;
+
+ IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);
+
+ /* First look in our cache */
+ en = ip_vs_lblc_get(svc->af, tbl, &iph->daddr);
+ if (en) {
+ /* We only hold a read lock, but this is atomic */
+ en->lastuse = jiffies;
+
+ /*
+ * If the destination is not available, i.e. it's in the trash,
+ * we must ignore it, as it may be removed from under our feet,
+ * if someone drops our reference count. Our caller only makes
+ * sure that destinations, that are not in the trash, are not
+ * moved to the trash, while we are scheduling. But anyone can
+ * free up entries from the trash at any time.
+ */
+
+ dest = en->dest;
+ if ((dest->flags & IP_VS_DEST_F_AVAILABLE) &&
+ atomic_read(&dest->weight) > 0 && !is_overloaded(dest, svc))
+ goto out;
+ }
+
+ /* No cache entry or it is invalid, time to schedule */
+ dest = __ip_vs_lblc_schedule(svc);
+ if (!dest) {
+ ip_vs_scheduler_err(svc, "no destination available");
+ 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_lblc_new(tbl, &iph->daddr, svc->af, dest);
+ spin_unlock_bh(&svc->sched_lock);
+
+out:
+ IP_VS_DBG_BUF(6, "LBLC: destination IP address %s --> server %s:%d\n",
+ IP_VS_DBG_ADDR(svc->af, &iph->daddr),
+ IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port));
+
+ return dest;
+}
+
+
+/*
+ * IPVS LBLC Scheduler structure
+ */
+static struct ip_vs_scheduler ip_vs_lblc_scheduler = {
+ .name = "lblc",
+ .refcnt = ATOMIC_INIT(0),
+ .module = THIS_MODULE,
+ .n_list = LIST_HEAD_INIT(ip_vs_lblc_scheduler.n_list),
+ .init_service = ip_vs_lblc_init_svc,
+ .done_service = ip_vs_lblc_done_svc,
+ .schedule = ip_vs_lblc_schedule,
+};
+
+/*
+ * per netns init.
+ */
+#ifdef CONFIG_SYSCTL
+static int __net_init __ip_vs_lblc_init(struct net *net)
+{
+ struct netns_ipvs *ipvs = net_ipvs(net);
+
+ if (!ipvs)
+ return -ENOENT;
+
+ if (!net_eq(net, &init_net)) {
+ ipvs->lblc_ctl_table = kmemdup(vs_vars_table,
+ sizeof(vs_vars_table),
+ GFP_KERNEL);
+ if (ipvs->lblc_ctl_table == NULL)
+ return -ENOMEM;
+
+ /* Don't export sysctls to unprivileged users */
+ if (net->user_ns != &init_user_ns)
+ ipvs->lblc_ctl_table[0].procname = NULL;
+
+ } else
+ ipvs->lblc_ctl_table = vs_vars_table;
+ ipvs->sysctl_lblc_expiration = DEFAULT_EXPIRATION;
+ ipvs->lblc_ctl_table[0].data = &ipvs->sysctl_lblc_expiration;
+
+ ipvs->lblc_ctl_header =
+ register_net_sysctl(net, "net/ipv4/vs", ipvs->lblc_ctl_table);
+ if (!ipvs->lblc_ctl_header) {
+ if (!net_eq(net, &init_net))
+ kfree(ipvs->lblc_ctl_table);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void __net_exit __ip_vs_lblc_exit(struct net *net)
+{
+ struct netns_ipvs *ipvs = net_ipvs(net);
+
+ unregister_net_sysctl_table(ipvs->lblc_ctl_header);
+
+ if (!net_eq(net, &init_net))
+ kfree(ipvs->lblc_ctl_table);
+}
+
+#else
+
+static int __net_init __ip_vs_lblc_init(struct net *net) { return 0; }
+static void __net_exit __ip_vs_lblc_exit(struct net *net) { }
+
+#endif
+
+static struct pernet_operations ip_vs_lblc_ops = {
+ .init = __ip_vs_lblc_init,
+ .exit = __ip_vs_lblc_exit,
+};
+
+static int __init ip_vs_lblc_init(void)
+{
+ int ret;
+
+ ret = register_pernet_subsys(&ip_vs_lblc_ops);
+ if (ret)
+ return ret;
+
+ ret = register_ip_vs_scheduler(&ip_vs_lblc_scheduler);
+ if (ret)
+ unregister_pernet_subsys(&ip_vs_lblc_ops);
+ return ret;
+}
+
+static void __exit ip_vs_lblc_cleanup(void)
+{
+ unregister_ip_vs_scheduler(&ip_vs_lblc_scheduler);
+ unregister_pernet_subsys(&ip_vs_lblc_ops);
+ rcu_barrier();
+}
+
+
+module_init(ip_vs_lblc_init);
+module_exit(ip_vs_lblc_cleanup);
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-07 05:33:42 +0000