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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/netfilter/ipvs/ip_vs_lblc.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_lblc.c')
-rw-r--r-- | net/netfilter/ipvs/ip_vs_lblc.c | 630 |
1 files changed, 630 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..7ac7473e3 --- /dev/null +++ b/net/netfilter/ipvs/ip_vs_lblc.c @@ -0,0 +1,630 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IPVS: Locality-Based Least-Connection scheduling module + * + * Authors: Wensong Zhang <wensong@gnuchina.org> + * + * 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> +#include <linux/hash.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 */ + struct ip_vs_service *svc; /* pointer back to service */ + 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 hash_32(ntohl(addr_fold), IP_VS_LBLC_TAB_BITS); +} + + +/* + * 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 = true; + 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 + return svc->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(struct timer_list *t) +{ + struct ip_vs_lblc_table *tbl = from_timer(tbl, t, periodic_timer); + struct ip_vs_service *svc = tbl->svc; + 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 = false; + tbl->svc = svc; + atomic_set(&tbl->entries, 0); + + /* + * Hook periodic timer for garbage collection + */ + timer_setup(&tbl->periodic_timer, ip_vs_lblc_check_expire, 0); + 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), + refcount_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"); |