/*
* IPVS An implementation of the IP virtual server support for the
* LINUX operating system. IPVS is now implemented as a module
* over the Netfilter framework. IPVS can be used to build a
* high-performance and highly available server based on a
* cluster of servers.
*
* Version: $Id: ip_vs_conn.c,v 1.31 2003/04/18 09:03:16 wensong Exp $
*
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
* Peter Kese <peter.kese@ijs.si>
* Julian Anastasov <ja@ssi.bg>
*
* 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.
*
* The IPVS code for kernel 2.2 was done by Wensong Zhang and Peter Kese,
* with changes/fixes from Julian Anastasov, Lars Marowsky-Bree, Horms
* and others. Many code here is taken from IP MASQ code of kernel 2.2.
*
* Changes:
*
*/
#include <linux/interrupt.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/proc_fs.h> /* for proc_net_* */
#include <linux/seq_file.h>
#include <linux/jhash.h>
#include <linux/random.h>
#include <net/net_namespace.h>
#include <net/ip_vs.h>
/*
* Connection hash table: for input and output packets lookups of IPVS
*/
static struct list_head *ip_vs_conn_tab;
/* SLAB cache for IPVS connections */
static struct kmem_cache *ip_vs_conn_cachep __read_mostly;
/* counter for current IPVS connections */
static atomic_t ip_vs_conn_count = ATOMIC_INIT(0);
/* counter for no client port connections */
static atomic_t ip_vs_conn_no_cport_cnt = ATOMIC_INIT(0);
/* random value for IPVS connection hash */
static unsigned int ip_vs_conn_rnd;
/*
* Fine locking granularity for big connection hash table
*/
#define CT_LOCKARRAY_BITS 4
#define CT_LOCKARRAY_SIZE (1<<CT_LOCKARRAY_BITS)
#define CT_LOCKARRAY_MASK (CT_LOCKARRAY_SIZE-1)
struct ip_vs_aligned_lock
{
rwlock_t l;
} __attribute__((__aligned__(SMP_CACHE_BYTES)));
/* lock array for conn table */
static struct ip_vs_aligned_lock
__ip_vs_conntbl_lock_array[CT_LOCKARRAY_SIZE] __cacheline_aligned;
static inline void ct_read_lock(unsigned key)
{
read_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_read_unlock(unsigned key)
{
read_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_write_lock(unsigned key)
{
write_lock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_write_unlock(unsigned key)
{
write_unlock(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_read_lock_bh(unsigned key)
{
read_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_read_unlock_bh(unsigned key)
{
read_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_write_lock_bh(unsigned key)
{
write_lock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
static inline void ct_write_unlock_bh(unsigned key)
{
write_unlock_bh(&__ip_vs_conntbl_lock_array[key&CT_LOCKARRAY_MASK].l);
}
/*
* Returns hash value for IPVS connection entry
*/
static unsigned int ip_vs_conn_hashkey(unsigned proto, __be32 addr, __be16 port)
{
return jhash_3words((__force u32)addr, (__force u32)port, proto, ip_vs_conn_rnd)
& IP_VS_CONN_TAB_MASK;
}
/*
* Hashes ip_vs_conn in ip_vs_conn_tab by proto,addr,port.
* returns bool success.
*/
static inline int ip_vs_conn_hash(struct ip_vs_conn *cp)
{
unsigned hash;
int ret;
/* Hash by protocol, client address and port */
hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
ct_write_lock(hash);
if (!(cp->flags & IP_VS_CONN_F_HASHED)) {
list_add(&cp->c_list, &ip_vs_conn_tab[hash]);
cp->flags |= IP_VS_CONN_F_HASHED;
atomic_inc(&cp->refcnt);
ret = 1;
} else {
IP_VS_ERR("ip_vs_conn_hash(): request for already hashed, "
"called from %p\n", __builtin_return_address(0));
ret = 0;
}
ct_write_unlock(hash);
return ret;
}
/*
* UNhashes ip_vs_conn from ip_vs_conn_tab.
* returns bool success.
*/
static inline int ip_vs_conn_unhash(struct ip_vs_conn *cp)
{
unsigned hash;
int ret;
/* unhash it and decrease its reference counter */
hash = ip_vs_conn_hashkey(cp->protocol, cp->caddr, cp->cport);
ct_write_lock(hash);
if (cp->flags & IP_VS_CONN_F_HASHED) {
list_del(&cp->c_list);
cp->flags &= ~IP_VS_CONN_F_HASHED;
atomic_dec(&cp->refcnt);
ret = 1;
} else
ret = 0;
ct_write_unlock(hash);
return ret;
}
/*
* Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
* Called for pkts coming from OUTside-to-INside.
* s_addr, s_port: pkt source address (foreign host)
* d_addr, d_port: pkt dest address (load balancer)
*/
static inline struct ip_vs_conn *__ip_vs_conn_in_get
(int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
{
unsigned hash;
struct ip_vs_conn *cp;
hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
ct_read_lock(hash);
list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
if (s_addr==cp->caddr && s_port==cp->cport &&
d_port==cp->vport && d_addr==cp->vaddr &&
((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&
protocol==cp->protocol) {
/* HIT */
atomic_inc(&cp->refcnt);
ct_read_unlock(hash);
return cp;
}
}
ct_read_unlock(hash);
return NULL;
}
struct ip_vs_conn *ip_vs_conn_in_get
(int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
{
struct ip_vs_conn *cp;
cp = __ip_vs_conn_in_get(protocol, s_addr, s_port, d_addr, d_port);
if (!cp && atomic_read(&ip_vs_conn_no_cport_cnt))
cp = __ip_vs_conn_in_get(protocol, s_addr, 0, d_addr, d_port);
IP_VS_DBG(9, "lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
ip_vs_proto_name(protocol),
NIPQUAD(s_addr), ntohs(s_port),
NIPQUAD(d_addr), ntohs(d_port),
cp?"hit":"not hit");
return cp;
}
/* Get reference to connection template */
struct ip_vs_conn *ip_vs_ct_in_get
(int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
{
unsigned hash;
struct ip_vs_conn *cp;
hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);
ct_read_lock(hash);
list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
if (s_addr==cp->caddr && s_port==cp->cport &&
d_port==cp->vport && d_addr==cp->vaddr &&
cp->flags & IP_VS_CONN_F_TEMPLATE &&
protocol==cp->protocol) {
/* HIT */
atomic_inc(&cp->refcnt);
goto out;
}
}
cp = NULL;
out:
ct_read_unlock(hash);
IP_VS_DBG(9, "template lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
ip_vs_proto_name(protocol),
NIPQUAD(s_addr), ntohs(s_port),
NIPQUAD(d_addr), ntohs(d_port),
cp?"hit":"not hit");
return cp;
}
/*
* Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
* Called for pkts coming from inside-to-OUTside.
* s_addr, s_port: pkt source address (inside host)
* d_addr, d_port: pkt dest address (foreign host)
*/
struct ip_vs_conn *ip_vs_conn_out_get
(int protocol, __be32 s_addr, __be16 s_port, __be32 d_addr, __be16 d_port)
{
unsigned hash;
struct ip_vs_conn *cp, *ret=NULL;
/*
* Check for "full" addressed entries
*/
hash = ip_vs_conn_hashkey(protocol, d_addr, d_port);
ct_read_lock(hash);
list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
if (d_addr == cp->caddr && d_port == cp->cport &&
s_port == cp->dport && s_addr == cp->daddr &&
protocol == cp->protocol) {
/* HIT */
atomic_inc(&cp->refcnt);
ret = cp;
break;
}
}
ct_read_unlock(hash);
IP_VS_DBG(9, "lookup/out %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",
ip_vs_proto_name(protocol),
NIPQUAD(s_addr), ntohs(s_port),
NIPQUAD(d_addr), ntohs(d_port),
ret?"hit":"not hit");
return ret;
}
/*
* Put back the conn and restart its timer with its timeout
*/
void ip_vs_conn_put(struct ip_vs_conn *cp)
{
/* reset it expire in its timeout */
mod_timer(&cp->timer, jiffies+cp->timeout);
__ip_vs_conn_put(cp);
}
/*
* Fill a no_client_port connection with a client port number
*/
void ip_vs_conn_fill_cport(struct ip_vs_conn *cp, __be16 cport)
{
if (ip_vs_conn_unhash(cp)) {
spin_lock(&cp->lock);
if (cp->flags & IP_VS_CONN_F_NO_CPORT) {
atomic_dec(&ip_vs_conn_no_cport_cnt);
cp->flags &= ~IP_VS_CONN_F_NO_CPORT;
cp->cport = cport;
}
spin_unlock(&cp->lock);
/* hash on new dport */
ip_vs_conn_hash(cp);
}
}
/*
* Bind a connection entry with the corresponding packet_xmit.
* Called by ip_vs_conn_new.
*/
static inline void ip_vs_bind_xmit(struct ip_vs_conn *cp)
{
switch (IP_VS_FWD_METHOD(cp)) {
case IP_VS_CONN_F_MASQ:
cp->packet_xmit = ip_vs_nat_xmit;
break;
case IP_VS_CONN_F_TUNNEL:
cp->packet_xmit = ip_vs_tunnel_xmit;
break;
case IP_VS_CONN_F_DROUTE:
cp->packet_xmit = ip_vs_dr_xmit;
break;
case IP_VS_CONN_F_LOCALNODE:
cp->packet_xmit = ip_vs_null_xmit;
break;
case IP_VS_CONN_F_BYPASS:
cp->packet_xmit = ip_vs_bypass_xmit;
break;
}
}
static inline int ip_vs_dest_totalconns(struct ip_vs_dest *dest)
{
return atomic_read(&dest->activeconns)
+ atomic_read(&dest->inactconns);
}
/*
* Bind a connection entry with a virtual service destination
* Called just after a new connection entry is created.
*/
static inline void
ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest)
{
/* if dest is NULL, then return directly */
if (!dest)
return;
/* Increase the refcnt counter of the dest */
atomic_inc(&dest->refcnt);
/* Bind with the destination and its corresponding transmitter */
cp->flags |= atomic_read(&dest->conn_flags);
cp->dest = dest;
IP_VS_DBG(7, "Bind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
"d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
"dest->refcnt:%d\n",
ip_vs_proto_name(cp->protocol),
NIPQUAD(cp->caddr), ntohs(cp->cport),
NIPQUAD(cp->vaddr), ntohs(cp->vport),
NIPQUAD(cp->daddr), ntohs(cp->dport),
ip_vs_fwd_tag(cp), cp->state,
cp->flags, atomic_read(&cp->refcnt),
atomic_read(&dest->refcnt));
/* Update the connection counters */
if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
/* It is a normal connection, so increase the inactive
connection counter because it is in TCP SYNRECV
state (inactive) or other protocol inacive state */
atomic_inc(&dest->inactconns);
} else {
/* It is a persistent connection/template, so increase
the peristent connection counter */
atomic_inc(&dest->persistconns);
}
if (dest->u_threshold != 0 &&
ip_vs_dest_totalconns(dest) >= dest->u_threshold)
dest->flags |= IP_VS_DEST_F_OVERLOAD;
}
/*
* Check if there is a destination for the connection, if so
* bind the connection to the destination.
*/
struct ip_vs_dest *ip_vs_try_bind_dest(struct ip_vs_conn *cp)
{
struct ip_vs_dest *dest;
if ((cp) && (!cp->dest)) {
dest = ip_vs_find_dest(cp->daddr, cp->dport,
cp->vaddr, cp->vport, cp->protocol);
ip_vs_bind_dest(cp, dest);
return dest;
} else
return NULL;
}
/*
* Unbind a connection entry with its VS destination
* Called by the ip_vs_conn_expire function.
*/
static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp)
{
struct ip_vs_dest *dest = cp->dest;
if (!dest)
return;
IP_VS_DBG(7, "Unbind-dest %s c:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
"d:%u.%u.%u.%u:%d fwd:%c s:%u conn->flags:%X conn->refcnt:%d "
"dest->refcnt:%d\n",
ip_vs_proto_name(cp->protocol),
NIPQUAD(cp->caddr), ntohs(cp->cport),
NIPQUAD(cp->vaddr), ntohs(cp->vport),
NIPQUAD(cp->daddr), ntohs(cp->dport),
ip_vs_fwd_tag(cp), cp->state,
cp->flags, atomic_read(&cp->refcnt),
atomic_read(&dest->refcnt));
/* Update the connection counters */
if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {
/* It is a normal connection, so decrease the inactconns
or activeconns counter */
if (cp->flags & IP_VS_CONN_F_INACTIVE) {
atomic_dec(&dest->inactconns);
} else {
atomic_dec(&dest->activeconns);
}
} else {
/* It is a persistent connection/template, so decrease
the peristent connection counter */
atomic_dec(&dest->persistconns);
}
if (dest->l_threshold != 0) {
if (ip_vs_dest_totalconns(dest) < dest->l_threshold)
dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
} else if (dest->u_threshold != 0) {
if (ip_vs_dest_totalconns(dest) * 4 < dest->u_threshold * 3)
dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
} else {
if (dest->flags & IP_VS_DEST_F_OVERLOAD)
dest->flags &= ~IP_VS_DEST_F_OVERLOAD;
}
/*
* Simply decrease the refcnt of the dest, because the
* dest will be either in service's destination list
* or in the trash.
*/
atomic_dec(&dest->refcnt);
}
/*
* Checking if the destination of a connection template is available.
* If available, return 1, otherwise invalidate this connection
* template and return 0.
*/
int ip_vs_check_template(struct ip_vs_conn *ct)
{
struct ip_vs_dest *dest = ct->dest;
/*
* Checking the dest server status.
*/
if ((dest == NULL) ||
!(dest->flags & IP_VS_DEST_F_AVAILABLE) ||
(sysctl_ip_vs_expire_quiescent_template &&
(atomic_read(&dest->weight) == 0))) {
IP_VS_DBG(9, "check_template: dest not available for "
"protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
"-> d:%u.%u.%u.%u:%d\n",
ip_vs_proto_name(ct->protocol),
NIPQUAD(ct->caddr), ntohs(ct->cport),
NIPQUAD(ct->vaddr), ntohs(ct->vport),
NIPQUAD(ct->daddr), ntohs(ct->dport));
/*
* Invalidate the connection template
*/
if (ct->vport != htons(0xffff)) {
if (ip_vs_conn_unhash(ct)) {
ct->dport = htons(0xffff);
ct->vport = htons(0xffff);
ct->cport = 0;
ip_vs_conn_hash(ct);
}
}
/*
* Simply decrease the refcnt of the template,
* don't restart its timer.
*/
atomic_dec(&ct->refcnt);
return 0;
}
return 1;
}
static void ip_vs_conn_expire(unsigned long data)
{
struct ip_vs_conn *cp = (struct ip_vs_conn *)data;
cp->timeout = 60*HZ;
/*
* hey, I'm using it
*/
atomic_inc(&cp->refcnt);
/*
* do I control anybody?
*/
if (atomic_read(&cp->n_control))
goto expire_later;
/*
* unhash it if it is hashed in the conn table
*/
if (!ip_vs_conn_unhash(cp))
goto expire_later;
/*
* refcnt==1 implies I'm the only one referrer
*/
if (likely(atomic_read(&cp->refcnt) == 1)) {
/* delete the timer if it is activated by other users */
if (timer_pending(&cp->timer))
del_timer(&cp->timer);
/* does anybody control me? */
if (cp->control)
ip_vs_control_del(cp);
if (unlikely(cp->app != NULL))
ip_vs_unbind_app(cp);
ip_vs_unbind_dest(cp);
if (cp->flags & IP_VS_CONN_F_NO_CPORT)
atomic_dec(&ip_vs_conn_no_cport_cnt);
atomic_dec(&ip_vs_conn_count);
kmem_cache_free(ip_vs_conn_cachep, cp);
return;
}
/* hash it back to the table */
ip_vs_conn_hash(cp);
expire_later:
IP_VS_DBG(7, "delayed: conn->refcnt-1=%d conn->n_control=%d\n",
atomic_read(&cp->refcnt)-1,
atomic_read(&cp->n_control));
ip_vs_conn_put(cp);
}
void ip_vs_conn_expire_now(struct ip_vs_conn *cp)
{
if (del_timer(&cp->timer))
mod_timer(&cp->timer, jiffies);
}
/*
* Create a new connection entry and hash it into the ip_vs_conn_tab
*/
struct ip_vs_conn *
ip_vs_conn_new(int proto, __be32 caddr, __be16 cport, __be32 vaddr, __be16 vport,
__be32 daddr, __be16 dport, unsigned flags,
struct ip_vs_dest *dest)
{
struct ip_vs_conn *cp;
struct ip_vs_protocol *pp = ip_vs_proto_get(proto);
cp = kmem_cache_zalloc(ip_vs_conn_cachep, GFP_ATOMIC);
if (cp == NULL) {
IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
return NULL;
}
INIT_LIST_HEAD(&cp->c_list);
init_timer(&cp->timer);
cp->timer.data = (unsigned long)cp;
cp->timer.function = ip_vs_conn_expire;
cp->protocol = proto;
cp->caddr = caddr;
cp->cport = cport;
cp->vaddr = vaddr;
cp->vport = vport;
cp->daddr = daddr;
cp->dport = dport;
cp->flags = flags;
spin_lock_init(&cp->lock);
/*
* Set the entry is referenced by the current thread before hashing
* it in the table, so that other thread run ip_vs_random_dropentry
* but cannot drop this entry.
*/
atomic_set(&cp->refcnt, 1);
atomic_set(&cp->n_control, 0);
atomic_set(&cp->in_pkts, 0);
atomic_inc(&ip_vs_conn_count);
if (flags & IP_VS_CONN_F_NO_CPORT)
atomic_inc(&ip_vs_conn_no_cport_cnt);
/* Bind the connection with a destination server */
ip_vs_bind_dest(cp, dest);
/* Set its state and timeout */
cp->state = 0;
cp->timeout = 3*HZ;
/* Bind its packet transmitter */
ip_vs_bind_xmit(cp);
if (unlikely(pp && atomic_read(&pp->appcnt)))
ip_vs_bind_app(cp, pp);
/* Hash it in the ip_vs_conn_tab finally */
ip_vs_conn_hash(cp);
return cp;
}
/*
* /proc/net/ip_vs_conn entries
*/
#ifdef CONFIG_PROC_FS
static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
{
int idx;
struct ip_vs_conn *cp;
for(idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
ct_read_lock_bh(idx);
list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
if (pos-- == 0) {
seq->private = &ip_vs_conn_tab[idx];
return cp;
}
}
ct_read_unlock_bh(idx);
}
return NULL;
}
static void *ip_vs_conn_seq_start(struct seq_file *seq, loff_t *pos)
{
seq->private = NULL;
return *pos ? ip_vs_conn_array(seq, *pos - 1) :SEQ_START_TOKEN;
}
static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct ip_vs_conn *cp = v;
struct list_head *e, *l = seq->private;
int idx;
++*pos;
if (v == SEQ_START_TOKEN)
return ip_vs_conn_array(seq, 0);
/* more on same hash chain? */
if ((e = cp->c_list.next) != l)
return list_entry(e, struct ip_vs_conn, c_list);
idx = l - ip_vs_conn_tab;
ct_read_unlock_bh(idx);
while (++idx < IP_VS_CONN_TAB_SIZE) {
ct_read_lock_bh(idx);
list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
seq->private = &ip_vs_conn_tab[idx];
return cp;
}
ct_read_unlock_bh(idx);
}
seq->private = NULL;
return NULL;
}
static void ip_vs_conn_seq_stop(struct seq_file *seq, void *v)
{
struct list_head *l = seq->private;
if (l)
ct_read_unlock_bh(l - ip_vs_conn_tab);
}
static int ip_vs_conn_seq_show(struct seq_file *seq, void *v)
{
if (v == SEQ_START_TOKEN)
seq_puts(seq,
"Pro FromIP FPrt ToIP TPrt DestIP DPrt State Expires\n");
else {
const struct ip_vs_conn *cp = v;
seq_printf(seq,
"%-3s %08X %04X %08X %04X %08X %04X %-11s %7lu\n",
ip_vs_proto_name(cp->protocol),
ntohl(cp->caddr), ntohs(cp->cport),
ntohl(cp->vaddr), ntohs(cp->vport),
ntohl(cp->daddr), ntohs(cp->dport),
ip_vs_state_name(cp->protocol, cp->state),
(cp->timer.expires-jiffies)/HZ);
}
return 0;
}
static const struct seq_operations ip_vs_conn_seq_ops = {
.start = ip_vs_conn_seq_start,
.next = ip_vs_conn_seq_next,
.stop = ip_vs_conn_seq_stop,
.show = ip_vs_conn_seq_show,
};
static int ip_vs_conn_open(struct inode *inode, struct file *file)
{
return seq_open(file, &ip_vs_conn_seq_ops);
}
static const struct file_operations ip_vs_conn_fops = {
.owner = THIS_MODULE,
.open = ip_vs_conn_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
#endif
/*
* Randomly drop connection entries before running out of memory
*/
static inline int todrop_entry(struct ip_vs_conn *cp)
{
/*
* The drop rate array needs tuning for real environments.
* Called from timer bh only => no locking
*/
static const char todrop_rate[9] = {0, 1, 2, 3, 4, 5, 6, 7, 8};
static char todrop_counter[9] = {0};
int i;
/* if the conn entry hasn't lasted for 60 seconds, don't drop it.
This will leave enough time for normal connection to get
through. */
if (time_before(cp->timeout + jiffies, cp->timer.expires + 60*HZ))
return 0;
/* Don't drop the entry if its number of incoming packets is not
located in [0, 8] */
i = atomic_read(&cp->in_pkts);
if (i > 8 || i < 0) return 0;
if (!todrop_rate[i]) return 0;
if (--todrop_counter[i] > 0) return 0;
todrop_counter[i] = todrop_rate[i];
return 1;
}
/* Called from keventd and must protect itself from softirqs */
void ip_vs_random_dropentry(void)
{
int idx;
struct ip_vs_conn *cp;
/*
* Randomly scan 1/32 of the whole table every second
*/
for (idx = 0; idx < (IP_VS_CONN_TAB_SIZE>>5); idx++) {
unsigned hash = net_random() & IP_VS_CONN_TAB_MASK;
/*
* Lock is actually needed in this loop.
*/
ct_write_lock_bh(hash);
list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {
if (cp->flags & IP_VS_CONN_F_TEMPLATE)
/* connection template */
continue;
if (cp->protocol == IPPROTO_TCP) {
switch(cp->state) {
case IP_VS_TCP_S_SYN_RECV:
case IP_VS_TCP_S_SYNACK:
break;
case IP_VS_TCP_S_ESTABLISHED:
if (todrop_entry(cp))
break;
continue;
default:
continue;
}
} else {
if (!todrop_entry(cp))
continue;
}
IP_VS_DBG(4, "del connection\n");
ip_vs_conn_expire_now(cp);
if (cp->control) {
IP_VS_DBG(4, "del conn template\n");
ip_vs_conn_expire_now(cp->control);
}
}
ct_write_unlock_bh(hash);
}
}
/*
* Flush all the connection entries in the ip_vs_conn_tab
*/
static void ip_vs_conn_flush(void)
{
int idx;
struct ip_vs_conn *cp;
flush_again:
for (idx=0; idx<IP_VS_CONN_TAB_SIZE; idx++) {
/*
* Lock is actually needed in this loop.
*/
ct_write_lock_bh(idx);
list_for_each_entry(cp, &ip_vs_conn_tab[idx], c_list) {
IP_VS_DBG(4, "del connection\n");
ip_vs_conn_expire_now(cp);
if (cp->control) {
IP_VS_DBG(4, "del conn template\n");
ip_vs_conn_expire_now(cp->control);
}
}
ct_write_unlock_bh(idx);
}
/* the counter may be not NULL, because maybe some conn entries
are run by slow timer handler or unhashed but still referred */
if (atomic_read(&ip_vs_conn_count) != 0) {
schedule();
goto flush_again;
}
}
int ip_vs_conn_init(void)
{
int idx;
/*
* Allocate the connection hash table and initialize its list heads
*/
ip_vs_conn_tab = vmalloc(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head));
if (!ip_vs_conn_tab)
return -ENOMEM;
/* Allocate ip_vs_conn slab cache */
ip_vs_conn_cachep = kmem_cache_create("ip_vs_conn",
sizeof(struct ip_vs_conn), 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!ip_vs_conn_cachep) {
vfree(ip_vs_conn_tab);
return -ENOMEM;
}
IP_VS_INFO("Connection hash table configured "
"(size=%d, memory=%ldKbytes)\n",
IP_VS_CONN_TAB_SIZE,
(long)(IP_VS_CONN_TAB_SIZE*sizeof(struct list_head))/1024);
IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
sizeof(struct ip_vs_conn));
for (idx = 0; idx < IP_VS_CONN_TAB_SIZE; idx++) {
INIT_LIST_HEAD(&ip_vs_conn_tab[idx]);
}
for (idx = 0; idx < CT_LOCKARRAY_SIZE; idx++) {
rwlock_init(&__ip_vs_conntbl_lock_array[idx].l);
}
proc_net_fops_create(&init_net, "ip_vs_conn", 0, &ip_vs_conn_fops);
/* calculate the random value for connection hash */
get_random_bytes(&ip_vs_conn_rnd, sizeof(ip_vs_conn_rnd));
return 0;
}
void ip_vs_conn_cleanup(void)
{
/* flush all the connection entries first */
ip_vs_conn_flush();
/* Release the empty cache */
kmem_cache_destroy(ip_vs_conn_cachep);
proc_net_remove(&init_net, "ip_vs_conn");
vfree(ip_vs_conn_tab);
}
