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linux-stable-rt/net/ipv4/ipvs/ip_vs_sync.c

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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_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;
if (buflen < sizeof(struct ip_vs_sync_mesg)) {
IP_VS_ERR_RL("sync message header too short\n");
return;
}
/* Convert size back to host byte order */
m->size = ntohs(m->size);
if (buflen != m->size) {
IP_VS_ERR_RL("bogus sync message size\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;
if (p + SIMPLE_CONN_SIZE > buffer+buflen) {
IP_VS_ERR_RL("bogus conn in sync message\n");
return;
}
s = (struct ip_vs_sync_conn *) p;
flags = ntohs(s->flags) | IP_VS_CONN_F_SYNC;
flags &= ~IP_VS_CONN_F_HASHED;
if (flags & IP_VS_CONN_F_SEQ_MASK) {
opt = (struct ip_vs_sync_conn_options *)&s[1];
p += FULL_CONN_SIZE;
if (p > buffer+buflen) {
IP_VS_ERR_RL("bogus conn options in sync message\n");
return;
}
} else {
opt = NULL;
p += SIMPLE_CONN_SIZE;
}
state = ntohs(s->state);
if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
pp = ip_vs_proto_get(s->protocol);
if (!pp) {
IP_VS_ERR_RL("Unsupported protocol %u in sync msg\n",
s->protocol);
continue;
}
if (state >= pp->num_states) {
IP_VS_DBG(2, "Invalid %s state %u in sync msg\n",
pp->name, state);
continue;
}
} else {
/* protocol in templates is not used for state/timeout */
pp = NULL;
if (state > 0) {
IP_VS_DBG(2, "Invalid template state %u in sync msg\n",
state);
state = 0;
}
}
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;
}
} else if (!cp->dest) {
dest = ip_vs_try_bind_dest(cp);
if (dest)
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 (opt)
memcpy(&cp->in_seq, opt, sizeof(*opt));
atomic_set(&cp->in_pkts, sysctl_ip_vs_sync_threshold[0]);
cp->state = state;
cp->old_state = cp->state;
/*
* We can not recover the right timeout for templates
* in all cases, we can not find the right fwmark
* virtual service. If needed, we can do it for
* non-fwmark persistent services.
*/
if (!(flags & IP_VS_CONN_F_TEMPLATE) && pp->timeout_table)
cp->timeout = pp->timeout_table[state];
else
cp->timeout = (3*60*HZ);
ip_vs_conn_put(cp);
}
}
/*
* 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", __func__, 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", __func__, 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;
}
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