diff options
Diffstat (limited to 'net/ipv4/ipvs/ip_vs_sync.c')
| -rw-r--r-- | net/ipv4/ipvs/ip_vs_sync.c | 892 |
1 files changed, 892 insertions, 0 deletions
diff --git a/net/ipv4/ipvs/ip_vs_sync.c b/net/ipv4/ipvs/ip_vs_sync.c new file mode 100644 index 00000000000..25c479550a3 --- /dev/null +++ b/net/ipv4/ipvs/ip_vs_sync.c @@ -0,0 +1,892 @@ +/* + * 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/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 <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) */ + __u16 cport; + __u16 vport; + __u16 dport; + __u32 caddr; /* client address */ + __u32 vaddr; /* virtual address */ + __u32 daddr; /* destination address */ + + /* Flags and state transition */ + __u16 flags; /* status flags */ + __u16 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 */ +}; + +#define IP_VS_SYNC_CONN_TIMEOUT (3*60*HZ) +#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; + 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++) { + s = (struct ip_vs_sync_conn *)p; + cp = ip_vs_conn_in_get(s->protocol, + s->caddr, s->cport, + s->vaddr, s->vport); + if (!cp) { + cp = ip_vs_conn_new(s->protocol, + s->caddr, s->cport, + s->vaddr, s->vport, + s->daddr, s->dport, + ntohs(s->flags), NULL); + if (!cp) { + IP_VS_ERR("ip_vs_conn_new failed\n"); + return; + } + cp->state = ntohs(s->state); + } else if (!cp->dest) { + /* it is an entry created by the synchronization */ + cp->state = ntohs(s->state); + cp->flags = ntohs(s->flags) | IP_VS_CONN_F_HASHED; + } /* Note that we don't touch its state and flags + if it is a normal entry. */ + + if (ntohs(s->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->timeout = IP_VS_SYNC_CONN_TIMEOUT; + 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(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(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(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(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; + u32 addr; + struct sockaddr_in sin; + + if ((dev = __dev_get_by_name(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; + + ssleep(1); + } + + /* 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; + + ssleep(1); + } + + /* 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; + + /* 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(¤t->sighand->siglock); + siginitsetinv(¤t->blocked, 0); + recalc_sigpending(); + spin_unlock_irq(¤t->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, current->pid); + complete((struct completion *)startup); + + /* 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 */ + 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); + + 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); + ssleep(1); + goto repeat; + } + + return 0; +} + + +int start_sync_thread(int state, char *mcast_ifn, __u8 syncid) +{ + DECLARE_COMPLETION(startup); + pid_t pid; + + if ((state == IP_VS_STATE_MASTER && sync_master_pid) || + (state == IP_VS_STATE_BACKUP && sync_backup_pid)) + return -EEXIST; + + IP_VS_DBG(7, "%s: pid %d\n", __FUNCTION__, current->pid); + 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) { + strcpy(ip_vs_master_mcast_ifn, mcast_ifn); + ip_vs_master_syncid = syncid; + } else { + strcpy(ip_vs_backup_mcast_ifn, mcast_ifn); + ip_vs_backup_syncid = syncid; + } + + repeat: + if ((pid = kernel_thread(fork_sync_thread, &startup, 0)) < 0) { + IP_VS_ERR("could not create fork_sync_thread due to %d... " + "retrying.\n", pid); + ssleep(1); + 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__, current->pid); + 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; +} |