/* * 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. * * Authors: Wensong Zhang * * 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 #include #include #include #include #include #include #include #include /* for ip_mc_join_group */ #include #include #include #include #include #include #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 socket *sock; char *buf; }; #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]; /* sync daemon tasks */ static struct task_struct *sync_master_thread; static struct task_struct *sync_backup_thread; /* multicast addr */ static struct sockaddr_in mcast_addr = { .sin_family = AF_INET, .sin_port = __constant_htons(IP_VS_SYNC_PORT), .sin_addr.s_addr = __constant_htonl(IP_VS_SYNC_GROUP), }; 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); } static inline void sb_queue_tail(struct ip_vs_sync_buff *sb) { spin_lock(&ip_vs_sync_lock); if (ip_vs_sync_state & IP_VS_STATE_MASTER) list_add_tail(&sb->list, &ip_vs_sync_queue); else ip_vs_sync_buff_release(sb); spin_unlock(&ip_vs_sync_lock); } /* * 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; inr_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; int result; /* First create a socket */ result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock); if (result < 0) { IP_VS_ERR("Error during creation of socket; terminating\n"); return ERR_PTR(result); } result = set_mcast_if(sock->sk, ip_vs_master_mcast_ifn); if (result < 0) { IP_VS_ERR("Error setting outbound mcast interface\n"); goto error; } set_mcast_loop(sock->sk, 0); set_mcast_ttl(sock->sk, 1); result = bind_mcastif_addr(sock, ip_vs_master_mcast_ifn); if (result < 0) { IP_VS_ERR("Error binding address of the mcast interface\n"); goto error; } result = sock->ops->connect(sock, (struct sockaddr *) &mcast_addr, sizeof(struct sockaddr), 0); if (result < 0) { IP_VS_ERR("Error connecting to the multicast addr\n"); goto error; } return sock; error: sock_release(sock); return ERR_PTR(result); } /* * Set up receiving multicast socket over UDP */ static struct socket * make_receive_sock(void) { struct socket *sock; int result; /* First create a socket */ result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock); if (result < 0) { IP_VS_ERR("Error during creation of socket; terminating\n"); return ERR_PTR(result); } /* it is equivalent to the REUSEADDR option in user-space */ sock->sk->sk_reuse = 1; result = sock->ops->bind(sock, (struct sockaddr *) &mcast_addr, sizeof(struct sockaddr)); if (result < 0) { IP_VS_ERR("Error binding to the multicast addr\n"); goto error; } /* join the multicast group */ result = join_mcast_group(sock->sk, (struct in_addr *) &mcast_addr.sin_addr, ip_vs_backup_mcast_ifn); if (result < 0) { IP_VS_ERR("Error joining to the multicast group\n"); goto error; } return sock; error: sock_release(sock); return ERR_PTR(result); } 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 int sync_thread_master(void *data) { struct ip_vs_sync_thread_data *tinfo = data; struct ip_vs_sync_buff *sb; IP_VS_INFO("sync thread started: state = MASTER, mcast_ifn = %s, " "syncid = %d\n", ip_vs_master_mcast_ifn, ip_vs_master_syncid); while (!kthread_should_stop()) { while ((sb = sb_dequeue())) { ip_vs_send_sync_msg(tinfo->sock, sb->mesg); ip_vs_sync_buff_release(sb); } /* check if entries stay in curr_sb for 2 seconds */ sb = get_curr_sync_buff(2 * HZ); if (sb) { ip_vs_send_sync_msg(tinfo->sock, sb->mesg); ip_vs_sync_buff_release(sb); } 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(tinfo->sock); kfree(tinfo); return 0; } static int sync_thread_backup(void *data) { struct ip_vs_sync_thread_data *tinfo = data; int len; IP_VS_INFO("sync thread started: state = BACKUP, mcast_ifn = %s, " "syncid = %d\n", ip_vs_backup_mcast_ifn, ip_vs_backup_syncid); while (!kthread_should_stop()) { /* do we have data now? */ while (!skb_queue_empty(&(tinfo->sock->sk->sk_receive_queue))) { len = ip_vs_receive(tinfo->sock, tinfo->buf, sync_recv_mesg_maxlen); if (len <= 0) { IP_VS_ERR("receiving message error\n"); break; } /* disable bottom half, because it accesses the data shared by softirq while getting/creating conns */ local_bh_disable(); ip_vs_process_message(tinfo->buf, len); local_bh_enable(); } msleep_interruptible(1000); } /* release the sending multicast socket */ sock_release(tinfo->sock); kfree(tinfo->buf); kfree(tinfo); return 0; } int start_sync_thread(int state, char *mcast_ifn, __u8 syncid) { struct ip_vs_sync_thread_data *tinfo; struct task_struct **realtask, *task; struct socket *sock; char *name, *buf = NULL; int (*threadfn)(void *data); int result = -ENOMEM; IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current)); IP_VS_DBG(7, "Each ip_vs_sync_conn entry needs %Zd bytes\n", sizeof(struct ip_vs_sync_conn)); if (state == IP_VS_STATE_MASTER) { if (sync_master_thread) return -EEXIST; strlcpy(ip_vs_master_mcast_ifn, mcast_ifn, sizeof(ip_vs_master_mcast_ifn)); ip_vs_master_syncid = syncid; realtask = &sync_master_thread; name = "ipvs_syncmaster"; threadfn = sync_thread_master; sock = make_send_sock(); } else if (state == IP_VS_STATE_BACKUP) { if (sync_backup_thread) return -EEXIST; strlcpy(ip_vs_backup_mcast_ifn, mcast_ifn, sizeof(ip_vs_backup_mcast_ifn)); ip_vs_backup_syncid = syncid; realtask = &sync_backup_thread; name = "ipvs_syncbackup"; threadfn = sync_thread_backup; sock = make_receive_sock(); } else { return -EINVAL; } if (IS_ERR(sock)) { result = PTR_ERR(sock); goto out; } set_sync_mesg_maxlen(state); if (state == IP_VS_STATE_BACKUP) { buf = kmalloc(sync_recv_mesg_maxlen, GFP_KERNEL); if (!buf) goto outsocket; } tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL); if (!tinfo) goto outbuf; tinfo->sock = sock; tinfo->buf = buf; task = kthread_run(threadfn, tinfo, name); if (IS_ERR(task)) { result = PTR_ERR(task); goto outtinfo; } /* mark as active */ *realtask = task; ip_vs_sync_state |= state; /* increase the module use count */ ip_vs_use_count_inc(); return 0; outtinfo: kfree(tinfo); outbuf: kfree(buf); outsocket: sock_release(sock); out: return result; } int stop_sync_thread(int state) { IP_VS_DBG(7, "%s: pid %d\n", __func__, task_pid_nr(current)); if (state == IP_VS_STATE_MASTER) { if (!sync_master_thread) return -ESRCH; IP_VS_INFO("stopping master sync thread %d ...\n", task_pid_nr(sync_master_thread)); /* * The lock synchronizes with sb_queue_tail(), so that we don't * add sync buffers to the queue, when we are already in * progress of stopping the master sync daemon. */ spin_lock(&ip_vs_sync_lock); ip_vs_sync_state &= ~IP_VS_STATE_MASTER; spin_unlock(&ip_vs_sync_lock); kthread_stop(sync_master_thread); sync_master_thread = NULL; } else if (state == IP_VS_STATE_BACKUP) { if (!sync_backup_thread) return -ESRCH; IP_VS_INFO("stopping backup sync thread %d ...\n", task_pid_nr(sync_backup_thread)); ip_vs_sync_state &= ~IP_VS_STATE_BACKUP; kthread_stop(sync_backup_thread); sync_backup_thread = NULL; } else { return -EINVAL; } /* decrease the module use count */ ip_vs_use_count_dec(); return 0; }