linux/net/ipv4/ipvs/ip_vs_sync.c
Rumen G. Bogdanovski b209639e8a [IPVS]: Create synced connections with their real state
With this patch the synced connections are created with their real state,
which can be changed on the next synchronizations if necessary. This way
on fail-over all the connections will be treated according to their actual
state, causing no scheduling problems (the active and the nonactive
connections have different weights in the schedulers).
The backwards compatibility is preserved and the existing tools will show
the true connection states even on the backup director.

Signed-off-by: Rumen G. Bogdanovski <rumen@voicecho.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-28 14:54:21 -08:00

982 lines
24 KiB
C

/*
* 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_sync.c,v 1.13 2003/06/08 09:31:19 wensong Exp $
*
* Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
*
* ip_vs_sync: sync connection info from master load balancer to backups
* through multicast
*
* Changes:
* Alexandre Cassen : Added master & backup support at a time.
* Alexandre Cassen : Added SyncID support for incoming sync
* messages filtering.
* Justin Ossevoort : Fix endian problem on sync message size.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/inetdevice.h>
#include <linux/net.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/igmp.h> /* for ip_mc_join_group */
#include <linux/udp.h>
#include <net/ip.h>
#include <net/sock.h>
#include <asm/uaccess.h> /* for get_fs and set_fs */
#include <net/ip_vs.h>
#define IP_VS_SYNC_GROUP 0xe0000051 /* multicast addr - 224.0.0.81 */
#define IP_VS_SYNC_PORT 8848 /* multicast port */
/*
* IPVS sync connection entry
*/
struct ip_vs_sync_conn {
__u8 reserved;
/* Protocol, addresses and port numbers */
__u8 protocol; /* Which protocol (TCP/UDP) */
__be16 cport;
__be16 vport;
__be16 dport;
__be32 caddr; /* client address */
__be32 vaddr; /* virtual address */
__be32 daddr; /* destination address */
/* Flags and state transition */
__be16 flags; /* status flags */
__be16 state; /* state info */
/* The sequence options start here */
};
struct ip_vs_sync_conn_options {
struct ip_vs_seq in_seq; /* incoming seq. struct */
struct ip_vs_seq out_seq; /* outgoing seq. struct */
};
struct ip_vs_sync_thread_data {
struct completion *startup;
int state;
};
#define SIMPLE_CONN_SIZE (sizeof(struct ip_vs_sync_conn))
#define FULL_CONN_SIZE \
(sizeof(struct ip_vs_sync_conn) + sizeof(struct ip_vs_sync_conn_options))
/*
The master mulitcasts messages to the backup load balancers in the
following format.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Count Conns | SyncID | Size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPVS Sync Connection (1) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
| . |
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPVS Sync Connection (n) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
#define SYNC_MESG_HEADER_LEN 4
struct ip_vs_sync_mesg {
__u8 nr_conns;
__u8 syncid;
__u16 size;
/* ip_vs_sync_conn entries start here */
};
/* the maximum length of sync (sending/receiving) message */
static int sync_send_mesg_maxlen;
static int sync_recv_mesg_maxlen;
struct ip_vs_sync_buff {
struct list_head list;
unsigned long firstuse;
/* pointers for the message data */
struct ip_vs_sync_mesg *mesg;
unsigned char *head;
unsigned char *end;
};
/* the sync_buff list head and the lock */
static LIST_HEAD(ip_vs_sync_queue);
static DEFINE_SPINLOCK(ip_vs_sync_lock);
/* current sync_buff for accepting new conn entries */
static struct ip_vs_sync_buff *curr_sb = NULL;
static DEFINE_SPINLOCK(curr_sb_lock);
/* ipvs sync daemon state */
volatile int ip_vs_sync_state = IP_VS_STATE_NONE;
volatile int ip_vs_master_syncid = 0;
volatile int ip_vs_backup_syncid = 0;
/* multicast interface name */
char ip_vs_master_mcast_ifn[IP_VS_IFNAME_MAXLEN];
char ip_vs_backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
/* multicast addr */
static struct sockaddr_in mcast_addr;
static inline void sb_queue_tail(struct ip_vs_sync_buff *sb)
{
spin_lock(&ip_vs_sync_lock);
list_add_tail(&sb->list, &ip_vs_sync_queue);
spin_unlock(&ip_vs_sync_lock);
}
static inline struct ip_vs_sync_buff * sb_dequeue(void)
{
struct ip_vs_sync_buff *sb;
spin_lock_bh(&ip_vs_sync_lock);
if (list_empty(&ip_vs_sync_queue)) {
sb = NULL;
} else {
sb = list_entry(ip_vs_sync_queue.next,
struct ip_vs_sync_buff,
list);
list_del(&sb->list);
}
spin_unlock_bh(&ip_vs_sync_lock);
return sb;
}
static inline struct ip_vs_sync_buff * ip_vs_sync_buff_create(void)
{
struct ip_vs_sync_buff *sb;
if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
return NULL;
if (!(sb->mesg=kmalloc(sync_send_mesg_maxlen, GFP_ATOMIC))) {
kfree(sb);
return NULL;
}
sb->mesg->nr_conns = 0;
sb->mesg->syncid = ip_vs_master_syncid;
sb->mesg->size = 4;
sb->head = (unsigned char *)sb->mesg + 4;
sb->end = (unsigned char *)sb->mesg + sync_send_mesg_maxlen;
sb->firstuse = jiffies;
return sb;
}
static inline void ip_vs_sync_buff_release(struct ip_vs_sync_buff *sb)
{
kfree(sb->mesg);
kfree(sb);
}
/*
* Get the current sync buffer if it has been created for more
* than the specified time or the specified time is zero.
*/
static inline struct ip_vs_sync_buff *
get_curr_sync_buff(unsigned long time)
{
struct ip_vs_sync_buff *sb;
spin_lock_bh(&curr_sb_lock);
if (curr_sb && (time == 0 ||
time_before(jiffies - curr_sb->firstuse, time))) {
sb = curr_sb;
curr_sb = NULL;
} else
sb = NULL;
spin_unlock_bh(&curr_sb_lock);
return sb;
}
/*
* Add an ip_vs_conn information into the current sync_buff.
* Called by ip_vs_in.
*/
void ip_vs_sync_conn(struct ip_vs_conn *cp)
{
struct ip_vs_sync_mesg *m;
struct ip_vs_sync_conn *s;
int len;
spin_lock(&curr_sb_lock);
if (!curr_sb) {
if (!(curr_sb=ip_vs_sync_buff_create())) {
spin_unlock(&curr_sb_lock);
IP_VS_ERR("ip_vs_sync_buff_create failed.\n");
return;
}
}
len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
SIMPLE_CONN_SIZE;
m = curr_sb->mesg;
s = (struct ip_vs_sync_conn *)curr_sb->head;
/* copy members */
s->protocol = cp->protocol;
s->cport = cp->cport;
s->vport = cp->vport;
s->dport = cp->dport;
s->caddr = cp->caddr;
s->vaddr = cp->vaddr;
s->daddr = cp->daddr;
s->flags = htons(cp->flags & ~IP_VS_CONN_F_HASHED);
s->state = htons(cp->state);
if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
struct ip_vs_sync_conn_options *opt =
(struct ip_vs_sync_conn_options *)&s[1];
memcpy(opt, &cp->in_seq, sizeof(*opt));
}
m->nr_conns++;
m->size += len;
curr_sb->head += len;
/* check if there is a space for next one */
if (curr_sb->head+FULL_CONN_SIZE > curr_sb->end) {
sb_queue_tail(curr_sb);
curr_sb = NULL;
}
spin_unlock(&curr_sb_lock);
/* synchronize its controller if it has */
if (cp->control)
ip_vs_sync_conn(cp->control);
}
/*
* Process received multicast message and create the corresponding
* ip_vs_conn entries.
*/
static void ip_vs_process_message(const char *buffer, const size_t buflen)
{
struct ip_vs_sync_mesg *m = (struct ip_vs_sync_mesg *)buffer;
struct ip_vs_sync_conn *s;
struct ip_vs_sync_conn_options *opt;
struct ip_vs_conn *cp;
struct ip_vs_protocol *pp;
struct ip_vs_dest *dest;
char *p;
int i;
/* Convert size back to host byte order */
m->size = ntohs(m->size);
if (buflen != m->size) {
IP_VS_ERR("bogus message\n");
return;
}
/* SyncID sanity check */
if (ip_vs_backup_syncid != 0 && m->syncid != ip_vs_backup_syncid) {
IP_VS_DBG(7, "Ignoring incoming msg with syncid = %d\n",
m->syncid);
return;
}
p = (char *)buffer + sizeof(struct ip_vs_sync_mesg);
for (i=0; i<m->nr_conns; i++) {
unsigned flags, state;
s = (struct ip_vs_sync_conn *)p;
flags = ntohs(s->flags) | IP_VS_CONN_F_SYNC;
state = ntohs(s->state);
if (!(flags & IP_VS_CONN_F_TEMPLATE))
cp = ip_vs_conn_in_get(s->protocol,
s->caddr, s->cport,
s->vaddr, s->vport);
else
cp = ip_vs_ct_in_get(s->protocol,
s->caddr, s->cport,
s->vaddr, s->vport);
if (!cp) {
/*
* Find the appropriate destination for the connection.
* If it is not found the connection will remain unbound
* but still handled.
*/
dest = ip_vs_find_dest(s->daddr, s->dport,
s->vaddr, s->vport,
s->protocol);
/* Set the approprite ativity flag */
if (s->protocol == IPPROTO_TCP) {
if (state != IP_VS_TCP_S_ESTABLISHED)
flags |= IP_VS_CONN_F_INACTIVE;
else
flags &= ~IP_VS_CONN_F_INACTIVE;
}
cp = ip_vs_conn_new(s->protocol,
s->caddr, s->cport,
s->vaddr, s->vport,
s->daddr, s->dport,
flags, dest);
if (dest)
atomic_dec(&dest->refcnt);
if (!cp) {
IP_VS_ERR("ip_vs_conn_new failed\n");
return;
}
cp->state = state;
} else if (!cp->dest) {
dest = ip_vs_try_bind_dest(cp);
if (!dest) {
/* it is an unbound entry created by
* synchronization */
cp->flags = flags | IP_VS_CONN_F_HASHED;
} else
atomic_dec(&dest->refcnt);
} else if ((cp->dest) && (cp->protocol == IPPROTO_TCP) &&
(cp->state != state)) {
/* update active/inactive flag for the connection */
dest = cp->dest;
if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
(state != IP_VS_TCP_S_ESTABLISHED)) {
atomic_dec(&dest->activeconns);
atomic_inc(&dest->inactconns);
cp->flags |= IP_VS_CONN_F_INACTIVE;
} else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
(state == IP_VS_TCP_S_ESTABLISHED)) {
atomic_inc(&dest->activeconns);
atomic_dec(&dest->inactconns);
cp->flags &= ~IP_VS_CONN_F_INACTIVE;
}
}
if (flags & IP_VS_CONN_F_SEQ_MASK) {
opt = (struct ip_vs_sync_conn_options *)&s[1];
memcpy(&cp->in_seq, opt, sizeof(*opt));
p += FULL_CONN_SIZE;
} else
p += SIMPLE_CONN_SIZE;
atomic_set(&cp->in_pkts, sysctl_ip_vs_sync_threshold[0]);
cp->state = state;
pp = ip_vs_proto_get(s->protocol);
cp->timeout = pp->timeout_table[cp->state];
ip_vs_conn_put(cp);
if (p > buffer+buflen) {
IP_VS_ERR("bogus message\n");
return;
}
}
}
/*
* Setup loopback of outgoing multicasts on a sending socket
*/
static void set_mcast_loop(struct sock *sk, u_char loop)
{
struct inet_sock *inet = inet_sk(sk);
/* setsockopt(sock, SOL_IP, IP_MULTICAST_LOOP, &loop, sizeof(loop)); */
lock_sock(sk);
inet->mc_loop = loop ? 1 : 0;
release_sock(sk);
}
/*
* Specify TTL for outgoing multicasts on a sending socket
*/
static void set_mcast_ttl(struct sock *sk, u_char ttl)
{
struct inet_sock *inet = inet_sk(sk);
/* setsockopt(sock, SOL_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)); */
lock_sock(sk);
inet->mc_ttl = ttl;
release_sock(sk);
}
/*
* Specifiy default interface for outgoing multicasts
*/
static int set_mcast_if(struct sock *sk, char *ifname)
{
struct net_device *dev;
struct inet_sock *inet = inet_sk(sk);
if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
return -ENODEV;
if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
return -EINVAL;
lock_sock(sk);
inet->mc_index = dev->ifindex;
/* inet->mc_addr = 0; */
release_sock(sk);
return 0;
}
/*
* Set the maximum length of sync message according to the
* specified interface's MTU.
*/
static int set_sync_mesg_maxlen(int sync_state)
{
struct net_device *dev;
int num;
if (sync_state == IP_VS_STATE_MASTER) {
if ((dev = __dev_get_by_name(&init_net, ip_vs_master_mcast_ifn)) == NULL)
return -ENODEV;
num = (dev->mtu - sizeof(struct iphdr) -
sizeof(struct udphdr) -
SYNC_MESG_HEADER_LEN - 20) / SIMPLE_CONN_SIZE;
sync_send_mesg_maxlen =
SYNC_MESG_HEADER_LEN + SIMPLE_CONN_SIZE * num;
IP_VS_DBG(7, "setting the maximum length of sync sending "
"message %d.\n", sync_send_mesg_maxlen);
} else if (sync_state == IP_VS_STATE_BACKUP) {
if ((dev = __dev_get_by_name(&init_net, ip_vs_backup_mcast_ifn)) == NULL)
return -ENODEV;
sync_recv_mesg_maxlen = dev->mtu -
sizeof(struct iphdr) - sizeof(struct udphdr);
IP_VS_DBG(7, "setting the maximum length of sync receiving "
"message %d.\n", sync_recv_mesg_maxlen);
}
return 0;
}
/*
* Join a multicast group.
* the group is specified by a class D multicast address 224.0.0.0/8
* in the in_addr structure passed in as a parameter.
*/
static int
join_mcast_group(struct sock *sk, struct in_addr *addr, char *ifname)
{
struct ip_mreqn mreq;
struct net_device *dev;
int ret;
memset(&mreq, 0, sizeof(mreq));
memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));
if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
return -ENODEV;
if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
return -EINVAL;
mreq.imr_ifindex = dev->ifindex;
lock_sock(sk);
ret = ip_mc_join_group(sk, &mreq);
release_sock(sk);
return ret;
}
static int bind_mcastif_addr(struct socket *sock, char *ifname)
{
struct net_device *dev;
__be32 addr;
struct sockaddr_in sin;
if ((dev = __dev_get_by_name(&init_net, ifname)) == NULL)
return -ENODEV;
addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
if (!addr)
IP_VS_ERR("You probably need to specify IP address on "
"multicast interface.\n");
IP_VS_DBG(7, "binding socket with (%s) %u.%u.%u.%u\n",
ifname, NIPQUAD(addr));
/* Now bind the socket with the address of multicast interface */
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = addr;
sin.sin_port = 0;
return sock->ops->bind(sock, (struct sockaddr*)&sin, sizeof(sin));
}
/*
* Set up sending multicast socket over UDP
*/
static struct socket * make_send_sock(void)
{
struct socket *sock;
/* First create a socket */
if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
IP_VS_ERR("Error during creation of socket; terminating\n");
return NULL;
}
if (set_mcast_if(sock->sk, ip_vs_master_mcast_ifn) < 0) {
IP_VS_ERR("Error setting outbound mcast interface\n");
goto error;
}
set_mcast_loop(sock->sk, 0);
set_mcast_ttl(sock->sk, 1);
if (bind_mcastif_addr(sock, ip_vs_master_mcast_ifn) < 0) {
IP_VS_ERR("Error binding address of the mcast interface\n");
goto error;
}
if (sock->ops->connect(sock,
(struct sockaddr*)&mcast_addr,
sizeof(struct sockaddr), 0) < 0) {
IP_VS_ERR("Error connecting to the multicast addr\n");
goto error;
}
return sock;
error:
sock_release(sock);
return NULL;
}
/*
* Set up receiving multicast socket over UDP
*/
static struct socket * make_receive_sock(void)
{
struct socket *sock;
/* First create a socket */
if (sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock) < 0) {
IP_VS_ERR("Error during creation of socket; terminating\n");
return NULL;
}
/* it is equivalent to the REUSEADDR option in user-space */
sock->sk->sk_reuse = 1;
if (sock->ops->bind(sock,
(struct sockaddr*)&mcast_addr,
sizeof(struct sockaddr)) < 0) {
IP_VS_ERR("Error binding to the multicast addr\n");
goto error;
}
/* join the multicast group */
if (join_mcast_group(sock->sk,
(struct in_addr*)&mcast_addr.sin_addr,
ip_vs_backup_mcast_ifn) < 0) {
IP_VS_ERR("Error joining to the multicast group\n");
goto error;
}
return sock;
error:
sock_release(sock);
return NULL;
}
static int
ip_vs_send_async(struct socket *sock, const char *buffer, const size_t length)
{
struct msghdr msg = {.msg_flags = MSG_DONTWAIT|MSG_NOSIGNAL};
struct kvec iov;
int len;
EnterFunction(7);
iov.iov_base = (void *)buffer;
iov.iov_len = length;
len = kernel_sendmsg(sock, &msg, &iov, 1, (size_t)(length));
LeaveFunction(7);
return len;
}
static void
ip_vs_send_sync_msg(struct socket *sock, struct ip_vs_sync_mesg *msg)
{
int msize;
msize = msg->size;
/* Put size in network byte order */
msg->size = htons(msg->size);
if (ip_vs_send_async(sock, (char *)msg, msize) != msize)
IP_VS_ERR("ip_vs_send_async error\n");
}
static int
ip_vs_receive(struct socket *sock, char *buffer, const size_t buflen)
{
struct msghdr msg = {NULL,};
struct kvec iov;
int len;
EnterFunction(7);
/* Receive a packet */
iov.iov_base = buffer;
iov.iov_len = (size_t)buflen;
len = kernel_recvmsg(sock, &msg, &iov, 1, buflen, 0);
if (len < 0)
return -1;
LeaveFunction(7);
return len;
}
static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
static pid_t sync_master_pid = 0;
static pid_t sync_backup_pid = 0;
static DECLARE_WAIT_QUEUE_HEAD(stop_sync_wait);
static int stop_master_sync = 0;
static int stop_backup_sync = 0;
static void sync_master_loop(void)
{
struct socket *sock;
struct ip_vs_sync_buff *sb;
/* create the sending multicast socket */
sock = make_send_sock();
if (!sock)
return;
IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, "
"syncid = %d\n",
ip_vs_master_mcast_ifn, ip_vs_master_syncid);
for (;;) {
while ((sb=sb_dequeue())) {
ip_vs_send_sync_msg(sock, sb->mesg);
ip_vs_sync_buff_release(sb);
}
/* check if entries stay in curr_sb for 2 seconds */
if ((sb = get_curr_sync_buff(2*HZ))) {
ip_vs_send_sync_msg(sock, sb->mesg);
ip_vs_sync_buff_release(sb);
}
if (stop_master_sync)
break;
msleep_interruptible(1000);
}
/* clean up the sync_buff queue */
while ((sb=sb_dequeue())) {
ip_vs_sync_buff_release(sb);
}
/* clean up the current sync_buff */
if ((sb = get_curr_sync_buff(0))) {
ip_vs_sync_buff_release(sb);
}
/* release the sending multicast socket */
sock_release(sock);
}
static void sync_backup_loop(void)
{
struct socket *sock;
char *buf;
int len;
if (!(buf = kmalloc(sync_recv_mesg_maxlen, GFP_ATOMIC))) {
IP_VS_ERR("sync_backup_loop: kmalloc error\n");
return;
}
/* create the receiving multicast socket */
sock = make_receive_sock();
if (!sock)
goto out;
IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, "
"syncid = %d\n",
ip_vs_backup_mcast_ifn, ip_vs_backup_syncid);
for (;;) {
/* do you have data now? */
while (!skb_queue_empty(&(sock->sk->sk_receive_queue))) {
if ((len =
ip_vs_receive(sock, buf,
sync_recv_mesg_maxlen)) <= 0) {
IP_VS_ERR("receiving message error\n");
break;
}
/* disable bottom half, because it accessed the data
shared by softirq while getting/creating conns */
local_bh_disable();
ip_vs_process_message(buf, len);
local_bh_enable();
}
if (stop_backup_sync)
break;
msleep_interruptible(1000);
}
/* release the sending multicast socket */
sock_release(sock);
out:
kfree(buf);
}
static void set_sync_pid(int sync_state, pid_t sync_pid)
{
if (sync_state == IP_VS_STATE_MASTER)
sync_master_pid = sync_pid;
else if (sync_state == IP_VS_STATE_BACKUP)
sync_backup_pid = sync_pid;
}
static void set_stop_sync(int sync_state, int set)
{
if (sync_state == IP_VS_STATE_MASTER)
stop_master_sync = set;
else if (sync_state == IP_VS_STATE_BACKUP)
stop_backup_sync = set;
else {
stop_master_sync = set;
stop_backup_sync = set;
}
}
static int sync_thread(void *startup)
{
DECLARE_WAITQUEUE(wait, current);
mm_segment_t oldmm;
int state;
const char *name;
struct ip_vs_sync_thread_data *tinfo = startup;
/* increase the module use count */
ip_vs_use_count_inc();
if (ip_vs_sync_state & IP_VS_STATE_MASTER && !sync_master_pid) {
state = IP_VS_STATE_MASTER;
name = "ipvs_syncmaster";
} else if (ip_vs_sync_state & IP_VS_STATE_BACKUP && !sync_backup_pid) {
state = IP_VS_STATE_BACKUP;
name = "ipvs_syncbackup";
} else {
IP_VS_BUG();
ip_vs_use_count_dec();
return -EINVAL;
}
daemonize(name);
oldmm = get_fs();
set_fs(KERNEL_DS);
/* Block all signals */
spin_lock_irq(&current->sighand->siglock);
siginitsetinv(&current->blocked, 0);
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
/* set the maximum length of sync message */
set_sync_mesg_maxlen(state);
/* set up multicast address */
mcast_addr.sin_family = AF_INET;
mcast_addr.sin_port = htons(IP_VS_SYNC_PORT);
mcast_addr.sin_addr.s_addr = htonl(IP_VS_SYNC_GROUP);
add_wait_queue(&sync_wait, &wait);
set_sync_pid(state, task_pid_nr(current));
complete(tinfo->startup);
/*
* once we call the completion queue above, we should
* null out that reference, since its allocated on the
* stack of the creating kernel thread
*/
tinfo->startup = NULL;
/* processing master/backup loop here */
if (state == IP_VS_STATE_MASTER)
sync_master_loop();
else if (state == IP_VS_STATE_BACKUP)
sync_backup_loop();
else IP_VS_BUG();
remove_wait_queue(&sync_wait, &wait);
/* thread exits */
/*
* If we weren't explicitly stopped, then we
* exited in error, and should undo our state
*/
if ((!stop_master_sync) && (!stop_backup_sync))
ip_vs_sync_state -= tinfo->state;
set_sync_pid(state, 0);
IP_VS_INFO("sync thread stopped!\n");
set_fs(oldmm);
/* decrease the module use count */
ip_vs_use_count_dec();
set_stop_sync(state, 0);
wake_up(&stop_sync_wait);
/*
* we need to free the structure that was allocated
* for us in start_sync_thread
*/
kfree(tinfo);
return 0;
}
static int fork_sync_thread(void *startup)
{
pid_t pid;
/* fork the sync thread here, then the parent process of the
sync thread is the init process after this thread exits. */
repeat:
if ((pid = kernel_thread(sync_thread, startup, 0)) < 0) {
IP_VS_ERR("could not create sync_thread due to %d... "
"retrying.\n", pid);
msleep_interruptible(1000);
goto repeat;
}
return 0;
}
int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
{
DECLARE_COMPLETION_ONSTACK(startup);
pid_t pid;
struct ip_vs_sync_thread_data *tinfo;
if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
(state == IP_VS_STATE_BACKUP && sync_backup_pid))
return -EEXIST;
/*
* Note that tinfo will be freed in sync_thread on exit
*/
tinfo = kmalloc(sizeof(struct ip_vs_sync_thread_data), GFP_KERNEL);
if (!tinfo)
return -ENOMEM;
IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, task_pid_nr(current));
IP_VS_DBG(7, "Each ip_vs_sync_conn entry need %Zd bytes\n",
sizeof(struct ip_vs_sync_conn));
ip_vs_sync_state |= state;
if (state == IP_VS_STATE_MASTER) {
strlcpy(ip_vs_master_mcast_ifn, mcast_ifn,
sizeof(ip_vs_master_mcast_ifn));
ip_vs_master_syncid = syncid;
} else {
strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn,
sizeof(ip_vs_backup_mcast_ifn));
ip_vs_backup_syncid = syncid;
}
tinfo->state = state;
tinfo->startup = &startup;
repeat:
if ((pid = kernel_thread(fork_sync_thread, tinfo, 0)) < 0) {
IP_VS_ERR("could not create fork_sync_thread due to %d... "
"retrying.\n", pid);
msleep_interruptible(1000);
goto repeat;
}
wait_for_completion(&startup);
return 0;
}
int stop_sync_thread(int state)
{
DECLARE_WAITQUEUE(wait, current);
if ((state == IP_VS_STATE_MASTER && !sync_master_pid) ||
(state == IP_VS_STATE_BACKUP && !sync_backup_pid))
return -ESRCH;
IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, task_pid_nr(current));
IP_VS_INFO("stopping sync thread %d ...\n",
(state == IP_VS_STATE_MASTER) ?
sync_master_pid : sync_backup_pid);
__set_current_state(TASK_UNINTERRUPTIBLE);
add_wait_queue(&stop_sync_wait, &wait);
set_stop_sync(state, 1);
ip_vs_sync_state -= state;
wake_up(&sync_wait);
schedule();
__set_current_state(TASK_RUNNING);
remove_wait_queue(&stop_sync_wait, &wait);
/* Note: no need to reap the sync thread, because its parent
process is the init process */
if ((state == IP_VS_STATE_MASTER && stop_master_sync) ||
(state == IP_VS_STATE_BACKUP && stop_backup_sync))
IP_VS_BUG();
return 0;
}