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linux/net/ipv4/ipvs/ip_vs_conn.c
Julian Anastasov 87375ab47c [IPVS]: ip_vs_ftp breaks connections using persistence 
ip_vs_ftp when loaded can create NAT connections with unknown client
port for passive FTP. For such expectations we lookup with cport=0 on
incoming packet but it matches the format of the persistence templates
causing packets to other persistent virtual servers to be forwarded to
real server without creating connection. Later the reply packets are
treated as foreign and not SNAT-ed.

This patch changes the connection lookup for packets from clients:

* introduce IP_VS_CONN_F_TEMPLATE connection flag to mark the
  connection as template

* create new connection lookup function just for templates -
  ip_vs_ct_in_get

* make sure ip_vs_conn_in_get hits only connections with
  IP_VS_CONN_F_NO_CPORT flag set when s_port is 0. By this way
  we avoid returning template when looking for cport=0 (ftp)

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-14 21:08:51 -07:00

939 lines
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/*
* 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/kernel.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/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 kmem_cache_t *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, __u32 addr, __u16 port)
{
return jhash_3words(addr, 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, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 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, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 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(7, "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, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 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(7, "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, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 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(7, "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, __u16 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(9, "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 flg:%X cnt:%d destcnt:%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;
}
/*
* 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(9, "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 flg:%X cnt:%d destcnt:%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 != 65535) {
if (ip_vs_conn_unhash(ct)) {
ct->dport = 65535;
ct->vport = 65535;
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: 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, __u32 caddr, __u16 cport, __u32 vaddr, __u16 vport,
__u32 daddr, __u16 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_alloc(ip_vs_conn_cachep, GFP_ATOMIC);
if (cp == NULL) {
IP_VS_ERR_RL("ip_vs_conn_new: no memory available.\n");
return NULL;
}
memset(cp, 0, sizeof(*cp));
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 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 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 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, 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("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("ip_vs_conn");
vfree(ip_vs_conn_tab);
}
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