Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / net / netfilter / ipvs / ip_vs_sync.c
diff --git a/kernel/net/netfilter/ipvs/ip_vs_sync.c b/kernel/net/netfilter/ipvs/ip_vs_sync.c
new file mode 100644 (file)
index 0000000..19b9cce
--- /dev/null
@@ -0,0 +1,1975 @@
+/*
+ * 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 1,   is capable of handling both version 0 and 1 messages.
+ *              Version 0 is the plain old format.
+ *              Note Version 0 receivers will just drop Ver 1 messages.
+ *              Version 1 is capable of handle IPv6, Persistence data,
+ *              time-outs, and firewall marks.
+ *              In ver.1 "ip_vs_sync_conn_options" will be sent in netw. order.
+ *              Ver. 0 can be turned on by sysctl -w net.ipv4.vs.sync_version=0
+ *
+ * Definitions  Message: is a complete datagram
+ *              Sync_conn: is a part of a Message
+ *              Param Data is an option to a Sync_conn.
+ *
+ * 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.
+ *     Hans Schillstrom        :       Added Version 1: i.e. IPv6,
+ *                                     Persistence support, fwmark and time-out.
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#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 <linux/err.h>
+#include <linux/kthread.h>
+#include <linux/wait.h>
+#include <linux/kernel.h>
+
+#include <asm/unaligned.h>             /* Used for ntoh_seq and hton_seq */
+
+#include <net/ip.h>
+#include <net/sock.h>
+
+#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 */
+
+#define SYNC_PROTO_VER  1              /* Protocol version in header */
+
+static struct lock_class_key __ipvs_sync_key;
+/*
+ *     IPVS sync connection entry
+ *     Version 0, i.e. original version.
+ */
+struct ip_vs_sync_conn_v0 {
+       __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 */
+};
+
+/*
+     Sync Connection format (sync_conn)
+
+       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
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |    Type       |    Protocol   | Ver.  |        Size           |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                             Flags                             |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |            State              |         cport                 |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |            vport              |         dport                 |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                             fwmark                            |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                             timeout  (in sec.)                |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                              ...                              |
+      |                        IP-Addresses  (v4 or v6)               |
+      |                              ...                              |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+  Optional Parameters.
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      | Param. Type    | Param. Length |   Param. data                |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
+      |                              ...                              |
+      |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                               | Param Type    | Param. Length |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                           Param  data                         |
+      |         Last Param data should be padded for 32 bit alignment |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+*/
+
+/*
+ *  Type 0, IPv4 sync connection format
+ */
+struct ip_vs_sync_v4 {
+       __u8                    type;
+       __u8                    protocol;       /* Which protocol (TCP/UDP) */
+       __be16                  ver_size;       /* Version msb 4 bits */
+       /* Flags and state transition */
+       __be32                  flags;          /* status flags */
+       __be16                  state;          /* state info   */
+       /* Protocol, addresses and port numbers */
+       __be16                  cport;
+       __be16                  vport;
+       __be16                  dport;
+       __be32                  fwmark;         /* Firewall mark from skb */
+       __be32                  timeout;        /* cp timeout */
+       __be32                  caddr;          /* client address */
+       __be32                  vaddr;          /* virtual address */
+       __be32                  daddr;          /* destination address */
+       /* The sequence options start here */
+       /* PE data padded to 32bit alignment after seq. options */
+};
+/*
+ * Type 2 messages IPv6
+ */
+struct ip_vs_sync_v6 {
+       __u8                    type;
+       __u8                    protocol;       /* Which protocol (TCP/UDP) */
+       __be16                  ver_size;       /* Version msb 4 bits */
+       /* Flags and state transition */
+       __be32                  flags;          /* status flags */
+       __be16                  state;          /* state info   */
+       /* Protocol, addresses and port numbers */
+       __be16                  cport;
+       __be16                  vport;
+       __be16                  dport;
+       __be32                  fwmark;         /* Firewall mark from skb */
+       __be32                  timeout;        /* cp timeout */
+       struct in6_addr         caddr;          /* client address */
+       struct in6_addr         vaddr;          /* virtual address */
+       struct in6_addr         daddr;          /* destination address */
+       /* The sequence options start here */
+       /* PE data padded to 32bit alignment after seq. options */
+};
+
+union ip_vs_sync_conn {
+       struct ip_vs_sync_v4    v4;
+       struct ip_vs_sync_v6    v6;
+};
+
+/* Bits in Type field in above */
+#define STYPE_INET6            0
+#define STYPE_F_INET6          (1 << STYPE_INET6)
+
+#define SVER_SHIFT             12              /* Shift to get version */
+#define SVER_MASK              0x0fff          /* Mask to strip version */
+
+#define IPVS_OPT_SEQ_DATA      1
+#define IPVS_OPT_PE_DATA       2
+#define IPVS_OPT_PE_NAME       3
+#define IPVS_OPT_PARAM         7
+
+#define IPVS_OPT_F_SEQ_DATA    (1 << (IPVS_OPT_SEQ_DATA-1))
+#define IPVS_OPT_F_PE_DATA     (1 << (IPVS_OPT_PE_DATA-1))
+#define IPVS_OPT_F_PE_NAME     (1 << (IPVS_OPT_PE_NAME-1))
+#define IPVS_OPT_F_PARAM       (1 << (IPVS_OPT_PARAM-1))
+
+struct ip_vs_sync_thread_data {
+       struct net *net;
+       struct socket *sock;
+       char *buf;
+       int id;
+};
+
+/* Version 0 definition of packet sizes */
+#define SIMPLE_CONN_SIZE  (sizeof(struct ip_vs_sync_conn_v0))
+#define FULL_CONN_SIZE  \
+(sizeof(struct ip_vs_sync_conn_v0) + sizeof(struct ip_vs_sync_conn_options))
+
+
+/*
+  The master mulitcasts messages (Datagrams) to the backup load balancers
+  in the following format.
+
+ Version 1:
+  Note, first byte should be Zero, so ver 0 receivers will drop the packet.
+
+       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
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |      0        |    SyncID     |            Size               |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |  Count Conns  |    Version    |    Reserved, set to Zero      |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                                                               |
+      |                    IPVS Sync Connection (1)                   |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                            .                                  |
+      ~                            .                                  ~
+      |                            .                                  |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+      |                                                               |
+      |                    IPVS Sync Connection (n)                   |
+      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+ Version 0 Header
+       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)                   |
+*/
+
+#define SYNC_MESG_HEADER_LEN   4
+#define MAX_CONNS_PER_SYNCBUFF 255 /* nr_conns in ip_vs_sync_mesg is 8 bit */
+
+/* Version 0 header */
+struct ip_vs_sync_mesg_v0 {
+       __u8                    nr_conns;
+       __u8                    syncid;
+       __be16                  size;
+
+       /* ip_vs_sync_conn entries start here */
+};
+
+/* Version 1 header */
+struct ip_vs_sync_mesg {
+       __u8                    reserved;       /* must be zero */
+       __u8                    syncid;
+       __be16                  size;
+       __u8                    nr_conns;
+       __s8                    version;        /* SYNC_PROTO_VER  */
+       __u16                   spare;
+       /* ip_vs_sync_conn entries start here */
+};
+
+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;
+};
+
+/*
+ * Copy of struct ip_vs_seq
+ * From unaligned network order to aligned host order
+ */
+static void ntoh_seq(struct ip_vs_seq *no, struct ip_vs_seq *ho)
+{
+       ho->init_seq       = get_unaligned_be32(&no->init_seq);
+       ho->delta          = get_unaligned_be32(&no->delta);
+       ho->previous_delta = get_unaligned_be32(&no->previous_delta);
+}
+
+/*
+ * Copy of struct ip_vs_seq
+ * From Aligned host order to unaligned network order
+ */
+static void hton_seq(struct ip_vs_seq *ho, struct ip_vs_seq *no)
+{
+       put_unaligned_be32(ho->init_seq, &no->init_seq);
+       put_unaligned_be32(ho->delta, &no->delta);
+       put_unaligned_be32(ho->previous_delta, &no->previous_delta);
+}
+
+static inline struct ip_vs_sync_buff *
+sb_dequeue(struct netns_ipvs *ipvs, struct ipvs_master_sync_state *ms)
+{
+       struct ip_vs_sync_buff *sb;
+
+       spin_lock_bh(&ipvs->sync_lock);
+       if (list_empty(&ms->sync_queue)) {
+               sb = NULL;
+               __set_current_state(TASK_INTERRUPTIBLE);
+       } else {
+               sb = list_entry(ms->sync_queue.next, struct ip_vs_sync_buff,
+                               list);
+               list_del(&sb->list);
+               ms->sync_queue_len--;
+               if (!ms->sync_queue_len)
+                       ms->sync_queue_delay = 0;
+       }
+       spin_unlock_bh(&ipvs->sync_lock);
+
+       return sb;
+}
+
+/*
+ * Create a new sync buffer for Version 1 proto.
+ */
+static inline struct ip_vs_sync_buff *
+ip_vs_sync_buff_create(struct netns_ipvs *ipvs)
+{
+       struct ip_vs_sync_buff *sb;
+
+       if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
+               return NULL;
+
+       sb->mesg = kmalloc(ipvs->send_mesg_maxlen, GFP_ATOMIC);
+       if (!sb->mesg) {
+               kfree(sb);
+               return NULL;
+       }
+       sb->mesg->reserved = 0;  /* old nr_conns i.e. must be zero now */
+       sb->mesg->version = SYNC_PROTO_VER;
+       sb->mesg->syncid = ipvs->master_syncid;
+       sb->mesg->size = htons(sizeof(struct ip_vs_sync_mesg));
+       sb->mesg->nr_conns = 0;
+       sb->mesg->spare = 0;
+       sb->head = (unsigned char *)sb->mesg + sizeof(struct ip_vs_sync_mesg);
+       sb->end = (unsigned char *)sb->mesg + ipvs->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 netns_ipvs *ipvs,
+                                struct ipvs_master_sync_state *ms)
+{
+       struct ip_vs_sync_buff *sb = ms->sync_buff;
+
+       spin_lock(&ipvs->sync_lock);
+       if (ipvs->sync_state & IP_VS_STATE_MASTER &&
+           ms->sync_queue_len < sysctl_sync_qlen_max(ipvs)) {
+               if (!ms->sync_queue_len)
+                       schedule_delayed_work(&ms->master_wakeup_work,
+                                             max(IPVS_SYNC_SEND_DELAY, 1));
+               ms->sync_queue_len++;
+               list_add_tail(&sb->list, &ms->sync_queue);
+               if ((++ms->sync_queue_delay) == IPVS_SYNC_WAKEUP_RATE)
+                       wake_up_process(ms->master_thread);
+       } else
+               ip_vs_sync_buff_release(sb);
+       spin_unlock(&ipvs->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(struct netns_ipvs *ipvs, struct ipvs_master_sync_state *ms,
+                  unsigned long time)
+{
+       struct ip_vs_sync_buff *sb;
+
+       spin_lock_bh(&ipvs->sync_buff_lock);
+       sb = ms->sync_buff;
+       if (sb && time_after_eq(jiffies - sb->firstuse, time)) {
+               ms->sync_buff = NULL;
+               __set_current_state(TASK_RUNNING);
+       } else
+               sb = NULL;
+       spin_unlock_bh(&ipvs->sync_buff_lock);
+       return sb;
+}
+
+static inline int
+select_master_thread_id(struct netns_ipvs *ipvs, struct ip_vs_conn *cp)
+{
+       return ((long) cp >> (1 + ilog2(sizeof(*cp)))) & ipvs->threads_mask;
+}
+
+/*
+ * Create a new sync buffer for Version 0 proto.
+ */
+static inline struct ip_vs_sync_buff *
+ip_vs_sync_buff_create_v0(struct netns_ipvs *ipvs)
+{
+       struct ip_vs_sync_buff *sb;
+       struct ip_vs_sync_mesg_v0 *mesg;
+
+       if (!(sb=kmalloc(sizeof(struct ip_vs_sync_buff), GFP_ATOMIC)))
+               return NULL;
+
+       sb->mesg = kmalloc(ipvs->send_mesg_maxlen, GFP_ATOMIC);
+       if (!sb->mesg) {
+               kfree(sb);
+               return NULL;
+       }
+       mesg = (struct ip_vs_sync_mesg_v0 *)sb->mesg;
+       mesg->nr_conns = 0;
+       mesg->syncid = ipvs->master_syncid;
+       mesg->size = htons(sizeof(struct ip_vs_sync_mesg_v0));
+       sb->head = (unsigned char *)mesg + sizeof(struct ip_vs_sync_mesg_v0);
+       sb->end = (unsigned char *)mesg + ipvs->send_mesg_maxlen;
+       sb->firstuse = jiffies;
+       return sb;
+}
+
+/* Check if connection is controlled by persistence */
+static inline bool in_persistence(struct ip_vs_conn *cp)
+{
+       for (cp = cp->control; cp; cp = cp->control) {
+               if (cp->flags & IP_VS_CONN_F_TEMPLATE)
+                       return true;
+       }
+       return false;
+}
+
+/* Check if conn should be synced.
+ * pkts: conn packets, use sysctl_sync_threshold to avoid packet check
+ * - (1) sync_refresh_period: reduce sync rate. Additionally, retry
+ *     sync_retries times with period of sync_refresh_period/8
+ * - (2) if both sync_refresh_period and sync_period are 0 send sync only
+ *     for state changes or only once when pkts matches sync_threshold
+ * - (3) templates: rate can be reduced only with sync_refresh_period or
+ *     with (2)
+ */
+static int ip_vs_sync_conn_needed(struct netns_ipvs *ipvs,
+                                 struct ip_vs_conn *cp, int pkts)
+{
+       unsigned long orig = ACCESS_ONCE(cp->sync_endtime);
+       unsigned long now = jiffies;
+       unsigned long n = (now + cp->timeout) & ~3UL;
+       unsigned int sync_refresh_period;
+       int sync_period;
+       int force;
+
+       /* Check if we sync in current state */
+       if (unlikely(cp->flags & IP_VS_CONN_F_TEMPLATE))
+               force = 0;
+       else if (unlikely(sysctl_sync_persist_mode(ipvs) && in_persistence(cp)))
+               return 0;
+       else if (likely(cp->protocol == IPPROTO_TCP)) {
+               if (!((1 << cp->state) &
+                     ((1 << IP_VS_TCP_S_ESTABLISHED) |
+                      (1 << IP_VS_TCP_S_FIN_WAIT) |
+                      (1 << IP_VS_TCP_S_CLOSE) |
+                      (1 << IP_VS_TCP_S_CLOSE_WAIT) |
+                      (1 << IP_VS_TCP_S_TIME_WAIT))))
+                       return 0;
+               force = cp->state != cp->old_state;
+               if (force && cp->state != IP_VS_TCP_S_ESTABLISHED)
+                       goto set;
+       } else if (unlikely(cp->protocol == IPPROTO_SCTP)) {
+               if (!((1 << cp->state) &
+                     ((1 << IP_VS_SCTP_S_ESTABLISHED) |
+                      (1 << IP_VS_SCTP_S_SHUTDOWN_SENT) |
+                      (1 << IP_VS_SCTP_S_SHUTDOWN_RECEIVED) |
+                      (1 << IP_VS_SCTP_S_SHUTDOWN_ACK_SENT) |
+                      (1 << IP_VS_SCTP_S_CLOSED))))
+                       return 0;
+               force = cp->state != cp->old_state;
+               if (force && cp->state != IP_VS_SCTP_S_ESTABLISHED)
+                       goto set;
+       } else {
+               /* UDP or another protocol with single state */
+               force = 0;
+       }
+
+       sync_refresh_period = sysctl_sync_refresh_period(ipvs);
+       if (sync_refresh_period > 0) {
+               long diff = n - orig;
+               long min_diff = max(cp->timeout >> 1, 10UL * HZ);
+
+               /* Avoid sync if difference is below sync_refresh_period
+                * and below the half timeout.
+                */
+               if (abs(diff) < min_t(long, sync_refresh_period, min_diff)) {
+                       int retries = orig & 3;
+
+                       if (retries >= sysctl_sync_retries(ipvs))
+                               return 0;
+                       if (time_before(now, orig - cp->timeout +
+                                       (sync_refresh_period >> 3)))
+                               return 0;
+                       n |= retries + 1;
+               }
+       }
+       sync_period = sysctl_sync_period(ipvs);
+       if (sync_period > 0) {
+               if (!(cp->flags & IP_VS_CONN_F_TEMPLATE) &&
+                   pkts % sync_period != sysctl_sync_threshold(ipvs))
+                       return 0;
+       } else if (sync_refresh_period <= 0 &&
+                  pkts != sysctl_sync_threshold(ipvs))
+               return 0;
+
+set:
+       cp->old_state = cp->state;
+       n = cmpxchg(&cp->sync_endtime, orig, n);
+       return n == orig || force;
+}
+
+/*
+ *      Version 0 , could be switched in by sys_ctl.
+ *      Add an ip_vs_conn information into the current sync_buff.
+ */
+static void ip_vs_sync_conn_v0(struct net *net, struct ip_vs_conn *cp,
+                              int pkts)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       struct ip_vs_sync_mesg_v0 *m;
+       struct ip_vs_sync_conn_v0 *s;
+       struct ip_vs_sync_buff *buff;
+       struct ipvs_master_sync_state *ms;
+       int id;
+       int len;
+
+       if (unlikely(cp->af != AF_INET))
+               return;
+       /* Do not sync ONE PACKET */
+       if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
+               return;
+
+       if (!ip_vs_sync_conn_needed(ipvs, cp, pkts))
+               return;
+
+       spin_lock_bh(&ipvs->sync_buff_lock);
+       if (!(ipvs->sync_state & IP_VS_STATE_MASTER)) {
+               spin_unlock_bh(&ipvs->sync_buff_lock);
+               return;
+       }
+
+       id = select_master_thread_id(ipvs, cp);
+       ms = &ipvs->ms[id];
+       buff = ms->sync_buff;
+       if (buff) {
+               m = (struct ip_vs_sync_mesg_v0 *) buff->mesg;
+               /* Send buffer if it is for v1 */
+               if (!m->nr_conns) {
+                       sb_queue_tail(ipvs, ms);
+                       ms->sync_buff = NULL;
+                       buff = NULL;
+               }
+       }
+       if (!buff) {
+               buff = ip_vs_sync_buff_create_v0(ipvs);
+               if (!buff) {
+                       spin_unlock_bh(&ipvs->sync_buff_lock);
+                       pr_err("ip_vs_sync_buff_create failed.\n");
+                       return;
+               }
+               ms->sync_buff = buff;
+       }
+
+       len = (cp->flags & IP_VS_CONN_F_SEQ_MASK) ? FULL_CONN_SIZE :
+               SIMPLE_CONN_SIZE;
+       m = (struct ip_vs_sync_mesg_v0 *) buff->mesg;
+       s = (struct ip_vs_sync_conn_v0 *) buff->head;
+
+       /* copy members */
+       s->reserved = 0;
+       s->protocol = cp->protocol;
+       s->cport = cp->cport;
+       s->vport = cp->vport;
+       s->dport = cp->dport;
+       s->caddr = cp->caddr.ip;
+       s->vaddr = cp->vaddr.ip;
+       s->daddr = cp->daddr.ip;
+       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 = htons(ntohs(m->size) + len);
+       buff->head += len;
+
+       /* check if there is a space for next one */
+       if (buff->head + FULL_CONN_SIZE > buff->end) {
+               sb_queue_tail(ipvs, ms);
+               ms->sync_buff = NULL;
+       }
+       spin_unlock_bh(&ipvs->sync_buff_lock);
+
+       /* synchronize its controller if it has */
+       cp = cp->control;
+       if (cp) {
+               if (cp->flags & IP_VS_CONN_F_TEMPLATE)
+                       pkts = atomic_add_return(1, &cp->in_pkts);
+               else
+                       pkts = sysctl_sync_threshold(ipvs);
+               ip_vs_sync_conn(net, cp->control, pkts);
+       }
+}
+
+/*
+ *      Add an ip_vs_conn information into the current sync_buff.
+ *      Called by ip_vs_in.
+ *      Sending Version 1 messages
+ */
+void ip_vs_sync_conn(struct net *net, struct ip_vs_conn *cp, int pkts)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       struct ip_vs_sync_mesg *m;
+       union ip_vs_sync_conn *s;
+       struct ip_vs_sync_buff *buff;
+       struct ipvs_master_sync_state *ms;
+       int id;
+       __u8 *p;
+       unsigned int len, pe_name_len, pad;
+
+       /* Handle old version of the protocol */
+       if (sysctl_sync_ver(ipvs) == 0) {
+               ip_vs_sync_conn_v0(net, cp, pkts);
+               return;
+       }
+       /* Do not sync ONE PACKET */
+       if (cp->flags & IP_VS_CONN_F_ONE_PACKET)
+               goto control;
+sloop:
+       if (!ip_vs_sync_conn_needed(ipvs, cp, pkts))
+               goto control;
+
+       /* Sanity checks */
+       pe_name_len = 0;
+       if (cp->pe_data_len) {
+               if (!cp->pe_data || !cp->dest) {
+                       IP_VS_ERR_RL("SYNC, connection pe_data invalid\n");
+                       return;
+               }
+               pe_name_len = strnlen(cp->pe->name, IP_VS_PENAME_MAXLEN);
+       }
+
+       spin_lock_bh(&ipvs->sync_buff_lock);
+       if (!(ipvs->sync_state & IP_VS_STATE_MASTER)) {
+               spin_unlock_bh(&ipvs->sync_buff_lock);
+               return;
+       }
+
+       id = select_master_thread_id(ipvs, cp);
+       ms = &ipvs->ms[id];
+
+#ifdef CONFIG_IP_VS_IPV6
+       if (cp->af == AF_INET6)
+               len = sizeof(struct ip_vs_sync_v6);
+       else
+#endif
+               len = sizeof(struct ip_vs_sync_v4);
+
+       if (cp->flags & IP_VS_CONN_F_SEQ_MASK)
+               len += sizeof(struct ip_vs_sync_conn_options) + 2;
+
+       if (cp->pe_data_len)
+               len += cp->pe_data_len + 2;     /* + Param hdr field */
+       if (pe_name_len)
+               len += pe_name_len + 2;
+
+       /* check if there is a space for this one  */
+       pad = 0;
+       buff = ms->sync_buff;
+       if (buff) {
+               m = buff->mesg;
+               pad = (4 - (size_t) buff->head) & 3;
+               /* Send buffer if it is for v0 */
+               if (buff->head + len + pad > buff->end || m->reserved) {
+                       sb_queue_tail(ipvs, ms);
+                       ms->sync_buff = NULL;
+                       buff = NULL;
+                       pad = 0;
+               }
+       }
+
+       if (!buff) {
+               buff = ip_vs_sync_buff_create(ipvs);
+               if (!buff) {
+                       spin_unlock_bh(&ipvs->sync_buff_lock);
+                       pr_err("ip_vs_sync_buff_create failed.\n");
+                       return;
+               }
+               ms->sync_buff = buff;
+               m = buff->mesg;
+       }
+
+       p = buff->head;
+       buff->head += pad + len;
+       m->size = htons(ntohs(m->size) + pad + len);
+       /* Add ev. padding from prev. sync_conn */
+       while (pad--)
+               *(p++) = 0;
+
+       s = (union ip_vs_sync_conn *)p;
+
+       /* Set message type  & copy members */
+       s->v4.type = (cp->af == AF_INET6 ? STYPE_F_INET6 : 0);
+       s->v4.ver_size = htons(len & SVER_MASK);        /* Version 0 */
+       s->v4.flags = htonl(cp->flags & ~IP_VS_CONN_F_HASHED);
+       s->v4.state = htons(cp->state);
+       s->v4.protocol = cp->protocol;
+       s->v4.cport = cp->cport;
+       s->v4.vport = cp->vport;
+       s->v4.dport = cp->dport;
+       s->v4.fwmark = htonl(cp->fwmark);
+       s->v4.timeout = htonl(cp->timeout / HZ);
+       m->nr_conns++;
+
+#ifdef CONFIG_IP_VS_IPV6
+       if (cp->af == AF_INET6) {
+               p += sizeof(struct ip_vs_sync_v6);
+               s->v6.caddr = cp->caddr.in6;
+               s->v6.vaddr = cp->vaddr.in6;
+               s->v6.daddr = cp->daddr.in6;
+       } else
+#endif
+       {
+               p += sizeof(struct ip_vs_sync_v4);      /* options ptr */
+               s->v4.caddr = cp->caddr.ip;
+               s->v4.vaddr = cp->vaddr.ip;
+               s->v4.daddr = cp->daddr.ip;
+       }
+       if (cp->flags & IP_VS_CONN_F_SEQ_MASK) {
+               *(p++) = IPVS_OPT_SEQ_DATA;
+               *(p++) = sizeof(struct ip_vs_sync_conn_options);
+               hton_seq((struct ip_vs_seq *)p, &cp->in_seq);
+               p += sizeof(struct ip_vs_seq);
+               hton_seq((struct ip_vs_seq *)p, &cp->out_seq);
+               p += sizeof(struct ip_vs_seq);
+       }
+       /* Handle pe data */
+       if (cp->pe_data_len && cp->pe_data) {
+               *(p++) = IPVS_OPT_PE_DATA;
+               *(p++) = cp->pe_data_len;
+               memcpy(p, cp->pe_data, cp->pe_data_len);
+               p += cp->pe_data_len;
+               if (pe_name_len) {
+                       /* Add PE_NAME */
+                       *(p++) = IPVS_OPT_PE_NAME;
+                       *(p++) = pe_name_len;
+                       memcpy(p, cp->pe->name, pe_name_len);
+                       p += pe_name_len;
+               }
+       }
+
+       spin_unlock_bh(&ipvs->sync_buff_lock);
+
+control:
+       /* synchronize its controller if it has */
+       cp = cp->control;
+       if (!cp)
+               return;
+       if (cp->flags & IP_VS_CONN_F_TEMPLATE)
+               pkts = atomic_add_return(1, &cp->in_pkts);
+       else
+               pkts = sysctl_sync_threshold(ipvs);
+       goto sloop;
+}
+
+/*
+ *  fill_param used by version 1
+ */
+static inline int
+ip_vs_conn_fill_param_sync(struct net *net, int af, union ip_vs_sync_conn *sc,
+                          struct ip_vs_conn_param *p,
+                          __u8 *pe_data, unsigned int pe_data_len,
+                          __u8 *pe_name, unsigned int pe_name_len)
+{
+#ifdef CONFIG_IP_VS_IPV6
+       if (af == AF_INET6)
+               ip_vs_conn_fill_param(net, af, sc->v6.protocol,
+                                     (const union nf_inet_addr *)&sc->v6.caddr,
+                                     sc->v6.cport,
+                                     (const union nf_inet_addr *)&sc->v6.vaddr,
+                                     sc->v6.vport, p);
+       else
+#endif
+               ip_vs_conn_fill_param(net, af, sc->v4.protocol,
+                                     (const union nf_inet_addr *)&sc->v4.caddr,
+                                     sc->v4.cport,
+                                     (const union nf_inet_addr *)&sc->v4.vaddr,
+                                     sc->v4.vport, p);
+       /* Handle pe data */
+       if (pe_data_len) {
+               if (pe_name_len) {
+                       char buff[IP_VS_PENAME_MAXLEN+1];
+
+                       memcpy(buff, pe_name, pe_name_len);
+                       buff[pe_name_len]=0;
+                       p->pe = __ip_vs_pe_getbyname(buff);
+                       if (!p->pe) {
+                               IP_VS_DBG(3, "BACKUP, no %s engine found/loaded\n",
+                                            buff);
+                               return 1;
+                       }
+               } else {
+                       IP_VS_ERR_RL("BACKUP, Invalid PE parameters\n");
+                       return 1;
+               }
+
+               p->pe_data = kmemdup(pe_data, pe_data_len, GFP_ATOMIC);
+               if (!p->pe_data) {
+                       module_put(p->pe->module);
+                       return -ENOMEM;
+               }
+               p->pe_data_len = pe_data_len;
+       }
+       return 0;
+}
+
+/*
+ *  Connection Add / Update.
+ *  Common for version 0 and 1 reception of backup sync_conns.
+ *  Param: ...
+ *         timeout is in sec.
+ */
+static void ip_vs_proc_conn(struct net *net, struct ip_vs_conn_param *param,
+                           unsigned int flags, unsigned int state,
+                           unsigned int protocol, unsigned int type,
+                           const union nf_inet_addr *daddr, __be16 dport,
+                           unsigned long timeout, __u32 fwmark,
+                           struct ip_vs_sync_conn_options *opt)
+{
+       struct ip_vs_dest *dest;
+       struct ip_vs_conn *cp;
+       struct netns_ipvs *ipvs = net_ipvs(net);
+
+       if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
+               cp = ip_vs_conn_in_get(param);
+               if (cp && ((cp->dport != dport) ||
+                          !ip_vs_addr_equal(cp->daf, &cp->daddr, daddr))) {
+                       if (!(flags & IP_VS_CONN_F_INACTIVE)) {
+                               ip_vs_conn_expire_now(cp);
+                               __ip_vs_conn_put(cp);
+                               cp = NULL;
+                       } else {
+                               /* This is the expiration message for the
+                                * connection that was already replaced, so we
+                                * just ignore it.
+                                */
+                               __ip_vs_conn_put(cp);
+                               kfree(param->pe_data);
+                               return;
+                       }
+               }
+       } else {
+               cp = ip_vs_ct_in_get(param);
+       }
+
+       if (cp) {
+               /* Free pe_data */
+               kfree(param->pe_data);
+
+               dest = cp->dest;
+               spin_lock_bh(&cp->lock);
+               if ((cp->flags ^ flags) & IP_VS_CONN_F_INACTIVE &&
+                   !(flags & IP_VS_CONN_F_TEMPLATE) && dest) {
+                       if (flags & IP_VS_CONN_F_INACTIVE) {
+                               atomic_dec(&dest->activeconns);
+                               atomic_inc(&dest->inactconns);
+                       } else {
+                               atomic_inc(&dest->activeconns);
+                               atomic_dec(&dest->inactconns);
+                       }
+               }
+               flags &= IP_VS_CONN_F_BACKUP_UPD_MASK;
+               flags |= cp->flags & ~IP_VS_CONN_F_BACKUP_UPD_MASK;
+               cp->flags = flags;
+               spin_unlock_bh(&cp->lock);
+               if (!dest)
+                       ip_vs_try_bind_dest(cp);
+       } else {
+               /*
+                * Find the appropriate destination for the connection.
+                * If it is not found the connection will remain unbound
+                * but still handled.
+                */
+               rcu_read_lock();
+               /* This function is only invoked by the synchronization
+                * code. We do not currently support heterogeneous pools
+                * with synchronization, so we can make the assumption that
+                * the svc_af is the same as the dest_af
+                */
+               dest = ip_vs_find_dest(net, type, type, daddr, dport,
+                                      param->vaddr, param->vport, protocol,
+                                      fwmark, flags);
+
+               cp = ip_vs_conn_new(param, type, daddr, dport, flags, dest,
+                                   fwmark);
+               rcu_read_unlock();
+               if (!cp) {
+                       kfree(param->pe_data);
+                       IP_VS_DBG(2, "BACKUP, add new conn. failed\n");
+                       return;
+               }
+               if (!(flags & IP_VS_CONN_F_TEMPLATE))
+                       kfree(param->pe_data);
+       }
+
+       if (opt)
+               memcpy(&cp->in_seq, opt, sizeof(*opt));
+       atomic_set(&cp->in_pkts, sysctl_sync_threshold(ipvs));
+       cp->state = state;
+       cp->old_state = cp->state;
+       /*
+        * For Ver 0 messages style
+        *  - Not possible to recover the right timeout for templates
+        *  - can not find the right fwmark
+        *    virtual service. If needed, we can do it for
+        *    non-fwmark persistent services.
+        * Ver 1 messages style.
+        *  - No problem.
+        */
+       if (timeout) {
+               if (timeout > MAX_SCHEDULE_TIMEOUT / HZ)
+                       timeout = MAX_SCHEDULE_TIMEOUT / HZ;
+               cp->timeout = timeout*HZ;
+       } else {
+               struct ip_vs_proto_data *pd;
+
+               pd = ip_vs_proto_data_get(net, protocol);
+               if (!(flags & IP_VS_CONN_F_TEMPLATE) && pd && pd->timeout_table)
+                       cp->timeout = pd->timeout_table[state];
+               else
+                       cp->timeout = (3*60*HZ);
+       }
+       ip_vs_conn_put(cp);
+}
+
+/*
+ *  Process received multicast message for Version 0
+ */
+static void ip_vs_process_message_v0(struct net *net, const char *buffer,
+                                    const size_t buflen)
+{
+       struct ip_vs_sync_mesg_v0 *m = (struct ip_vs_sync_mesg_v0 *)buffer;
+       struct ip_vs_sync_conn_v0 *s;
+       struct ip_vs_sync_conn_options *opt;
+       struct ip_vs_protocol *pp;
+       struct ip_vs_conn_param param;
+       char *p;
+       int i;
+
+       p = (char *)buffer + sizeof(struct ip_vs_sync_mesg_v0);
+       for (i=0; i<m->nr_conns; i++) {
+               unsigned int flags, state;
+
+               if (p + SIMPLE_CONN_SIZE > buffer+buflen) {
+                       IP_VS_ERR_RL("BACKUP v0, bogus conn\n");
+                       return;
+               }
+               s = (struct ip_vs_sync_conn_v0 *) 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("BACKUP v0, Dropping buffer bogus conn options\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_DBG(2, "BACKUP v0, Unsupported protocol %u\n",
+                                       s->protocol);
+                               continue;
+                       }
+                       if (state >= pp->num_states) {
+                               IP_VS_DBG(2, "BACKUP v0, Invalid %s state %u\n",
+                                       pp->name, state);
+                               continue;
+                       }
+               } else {
+                       /* protocol in templates is not used for state/timeout */
+                       if (state > 0) {
+                               IP_VS_DBG(2, "BACKUP v0, Invalid template state %u\n",
+                                       state);
+                               state = 0;
+                       }
+               }
+
+               ip_vs_conn_fill_param(net, AF_INET, s->protocol,
+                                     (const union nf_inet_addr *)&s->caddr,
+                                     s->cport,
+                                     (const union nf_inet_addr *)&s->vaddr,
+                                     s->vport, &param);
+
+               /* Send timeout as Zero */
+               ip_vs_proc_conn(net, &param, flags, state, s->protocol, AF_INET,
+                               (union nf_inet_addr *)&s->daddr, s->dport,
+                               0, 0, opt);
+       }
+}
+
+/*
+ * Handle options
+ */
+static inline int ip_vs_proc_seqopt(__u8 *p, unsigned int plen,
+                                   __u32 *opt_flags,
+                                   struct ip_vs_sync_conn_options *opt)
+{
+       struct ip_vs_sync_conn_options *topt;
+
+       topt = (struct ip_vs_sync_conn_options *)p;
+
+       if (plen != sizeof(struct ip_vs_sync_conn_options)) {
+               IP_VS_DBG(2, "BACKUP, bogus conn options length\n");
+               return -EINVAL;
+       }
+       if (*opt_flags & IPVS_OPT_F_SEQ_DATA) {
+               IP_VS_DBG(2, "BACKUP, conn options found twice\n");
+               return -EINVAL;
+       }
+       ntoh_seq(&topt->in_seq, &opt->in_seq);
+       ntoh_seq(&topt->out_seq, &opt->out_seq);
+       *opt_flags |= IPVS_OPT_F_SEQ_DATA;
+       return 0;
+}
+
+static int ip_vs_proc_str(__u8 *p, unsigned int plen, unsigned int *data_len,
+                         __u8 **data, unsigned int maxlen,
+                         __u32 *opt_flags, __u32 flag)
+{
+       if (plen > maxlen) {
+               IP_VS_DBG(2, "BACKUP, bogus par.data len > %d\n", maxlen);
+               return -EINVAL;
+       }
+       if (*opt_flags & flag) {
+               IP_VS_DBG(2, "BACKUP, Par.data found twice 0x%x\n", flag);
+               return -EINVAL;
+       }
+       *data_len = plen;
+       *data = p;
+       *opt_flags |= flag;
+       return 0;
+}
+/*
+ *   Process a Version 1 sync. connection
+ */
+static inline int ip_vs_proc_sync_conn(struct net *net, __u8 *p, __u8 *msg_end)
+{
+       struct ip_vs_sync_conn_options opt;
+       union  ip_vs_sync_conn *s;
+       struct ip_vs_protocol *pp;
+       struct ip_vs_conn_param param;
+       __u32 flags;
+       unsigned int af, state, pe_data_len=0, pe_name_len=0;
+       __u8 *pe_data=NULL, *pe_name=NULL;
+       __u32 opt_flags=0;
+       int retc=0;
+
+       s = (union ip_vs_sync_conn *) p;
+
+       if (s->v6.type & STYPE_F_INET6) {
+#ifdef CONFIG_IP_VS_IPV6
+               af = AF_INET6;
+               p += sizeof(struct ip_vs_sync_v6);
+#else
+               IP_VS_DBG(3,"BACKUP, IPv6 msg received, and IPVS is not compiled for IPv6\n");
+               retc = 10;
+               goto out;
+#endif
+       } else if (!s->v4.type) {
+               af = AF_INET;
+               p += sizeof(struct ip_vs_sync_v4);
+       } else {
+               return -10;
+       }
+       if (p > msg_end)
+               return -20;
+
+       /* Process optional params check Type & Len. */
+       while (p < msg_end) {
+               int ptype;
+               int plen;
+
+               if (p+2 > msg_end)
+                       return -30;
+               ptype = *(p++);
+               plen  = *(p++);
+
+               if (!plen || ((p + plen) > msg_end))
+                       return -40;
+               /* Handle seq option  p = param data */
+               switch (ptype & ~IPVS_OPT_F_PARAM) {
+               case IPVS_OPT_SEQ_DATA:
+                       if (ip_vs_proc_seqopt(p, plen, &opt_flags, &opt))
+                               return -50;
+                       break;
+
+               case IPVS_OPT_PE_DATA:
+                       if (ip_vs_proc_str(p, plen, &pe_data_len, &pe_data,
+                                          IP_VS_PEDATA_MAXLEN, &opt_flags,
+                                          IPVS_OPT_F_PE_DATA))
+                               return -60;
+                       break;
+
+               case IPVS_OPT_PE_NAME:
+                       if (ip_vs_proc_str(p, plen,&pe_name_len, &pe_name,
+                                          IP_VS_PENAME_MAXLEN, &opt_flags,
+                                          IPVS_OPT_F_PE_NAME))
+                               return -70;
+                       break;
+
+               default:
+                       /* Param data mandatory ? */
+                       if (!(ptype & IPVS_OPT_F_PARAM)) {
+                               IP_VS_DBG(3, "BACKUP, Unknown mandatory param %d found\n",
+                                         ptype & ~IPVS_OPT_F_PARAM);
+                               retc = 20;
+                               goto out;
+                       }
+               }
+               p += plen;  /* Next option */
+       }
+
+       /* Get flags and Mask off unsupported */
+       flags  = ntohl(s->v4.flags) & IP_VS_CONN_F_BACKUP_MASK;
+       flags |= IP_VS_CONN_F_SYNC;
+       state = ntohs(s->v4.state);
+
+       if (!(flags & IP_VS_CONN_F_TEMPLATE)) {
+               pp = ip_vs_proto_get(s->v4.protocol);
+               if (!pp) {
+                       IP_VS_DBG(3,"BACKUP, Unsupported protocol %u\n",
+                               s->v4.protocol);
+                       retc = 30;
+                       goto out;
+               }
+               if (state >= pp->num_states) {
+                       IP_VS_DBG(3, "BACKUP, Invalid %s state %u\n",
+                               pp->name, state);
+                       retc = 40;
+                       goto out;
+               }
+       } else {
+               /* protocol in templates is not used for state/timeout */
+               if (state > 0) {
+                       IP_VS_DBG(3, "BACKUP, Invalid template state %u\n",
+                               state);
+                       state = 0;
+               }
+       }
+       if (ip_vs_conn_fill_param_sync(net, af, s, &param, pe_data,
+                                      pe_data_len, pe_name, pe_name_len)) {
+               retc = 50;
+               goto out;
+       }
+       /* If only IPv4, just silent skip IPv6 */
+       if (af == AF_INET)
+               ip_vs_proc_conn(net, &param, flags, state, s->v4.protocol, af,
+                               (union nf_inet_addr *)&s->v4.daddr, s->v4.dport,
+                               ntohl(s->v4.timeout), ntohl(s->v4.fwmark),
+                               (opt_flags & IPVS_OPT_F_SEQ_DATA ? &opt : NULL)
+                               );
+#ifdef CONFIG_IP_VS_IPV6
+       else
+               ip_vs_proc_conn(net, &param, flags, state, s->v6.protocol, af,
+                               (union nf_inet_addr *)&s->v6.daddr, s->v6.dport,
+                               ntohl(s->v6.timeout), ntohl(s->v6.fwmark),
+                               (opt_flags & IPVS_OPT_F_SEQ_DATA ? &opt : NULL)
+                               );
+#endif
+       ip_vs_pe_put(param.pe);
+       return 0;
+       /* Error exit */
+out:
+       IP_VS_DBG(2, "BACKUP, Single msg dropped err:%d\n", retc);
+       return retc;
+
+}
+/*
+ *      Process received multicast message and create the corresponding
+ *      ip_vs_conn entries.
+ *      Handles Version 0 & 1
+ */
+static void ip_vs_process_message(struct net *net, __u8 *buffer,
+                                 const size_t buflen)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       struct ip_vs_sync_mesg *m2 = (struct ip_vs_sync_mesg *)buffer;
+       __u8 *p, *msg_end;
+       int i, nr_conns;
+
+       if (buflen < sizeof(struct ip_vs_sync_mesg_v0)) {
+               IP_VS_DBG(2, "BACKUP, message header too short\n");
+               return;
+       }
+
+       if (buflen != ntohs(m2->size)) {
+               IP_VS_DBG(2, "BACKUP, bogus message size\n");
+               return;
+       }
+       /* SyncID sanity check */
+       if (ipvs->backup_syncid != 0 && m2->syncid != ipvs->backup_syncid) {
+               IP_VS_DBG(7, "BACKUP, Ignoring syncid = %d\n", m2->syncid);
+               return;
+       }
+       /* Handle version 1  message */
+       if ((m2->version == SYNC_PROTO_VER) && (m2->reserved == 0)
+           && (m2->spare == 0)) {
+
+               msg_end = buffer + sizeof(struct ip_vs_sync_mesg);
+               nr_conns = m2->nr_conns;
+
+               for (i=0; i<nr_conns; i++) {
+                       union ip_vs_sync_conn *s;
+                       unsigned int size;
+                       int retc;
+
+                       p = msg_end;
+                       if (p + sizeof(s->v4) > buffer+buflen) {
+                               IP_VS_ERR_RL("BACKUP, Dropping buffer, to small\n");
+                               return;
+                       }
+                       s = (union ip_vs_sync_conn *)p;
+                       size = ntohs(s->v4.ver_size) & SVER_MASK;
+                       msg_end = p + size;
+                       /* Basic sanity checks */
+                       if (msg_end  > buffer+buflen) {
+                               IP_VS_ERR_RL("BACKUP, Dropping buffer, msg > buffer\n");
+                               return;
+                       }
+                       if (ntohs(s->v4.ver_size) >> SVER_SHIFT) {
+                               IP_VS_ERR_RL("BACKUP, Dropping buffer, Unknown version %d\n",
+                                             ntohs(s->v4.ver_size) >> SVER_SHIFT);
+                               return;
+                       }
+                       /* Process a single sync_conn */
+                       retc = ip_vs_proc_sync_conn(net, p, msg_end);
+                       if (retc < 0) {
+                               IP_VS_ERR_RL("BACKUP, Dropping buffer, Err: %d in decoding\n",
+                                            retc);
+                               return;
+                       }
+                       /* Make sure we have 32 bit alignment */
+                       msg_end = p + ((size + 3) & ~3);
+               }
+       } else {
+               /* Old type of message */
+               ip_vs_process_message_v0(net, buffer, buflen);
+               return;
+       }
+}
+
+
+/*
+ *      Setup sndbuf (mode=1) or rcvbuf (mode=0)
+ */
+static void set_sock_size(struct sock *sk, int mode, int val)
+{
+       /* setsockopt(sock, SOL_SOCKET, SO_SNDBUF, &val, sizeof(val)); */
+       /* setsockopt(sock, SOL_SOCKET, SO_RCVBUF, &val, sizeof(val)); */
+       lock_sock(sk);
+       if (mode) {
+               val = clamp_t(int, val, (SOCK_MIN_SNDBUF + 1) / 2,
+                             sysctl_wmem_max);
+               sk->sk_sndbuf = val * 2;
+               sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+       } else {
+               val = clamp_t(int, val, (SOCK_MIN_RCVBUF + 1) / 2,
+                             sysctl_rmem_max);
+               sk->sk_rcvbuf = val * 2;
+               sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
+       }
+       release_sock(sk);
+}
+
+/*
+ *      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);
+       struct net *net = sock_net(sk);
+
+       dev = __dev_get_by_name(net, ifname);
+       if (!dev)
+               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(struct net *net, int sync_state)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       struct net_device *dev;
+       int num;
+
+       if (sync_state == IP_VS_STATE_MASTER) {
+               dev = __dev_get_by_name(net, ipvs->master_mcast_ifn);
+               if (!dev)
+                       return -ENODEV;
+
+               num = (dev->mtu - sizeof(struct iphdr) -
+                      sizeof(struct udphdr) -
+                      SYNC_MESG_HEADER_LEN - 20) / SIMPLE_CONN_SIZE;
+               ipvs->send_mesg_maxlen = SYNC_MESG_HEADER_LEN +
+                       SIMPLE_CONN_SIZE * min(num, MAX_CONNS_PER_SYNCBUFF);
+               IP_VS_DBG(7, "setting the maximum length of sync sending "
+                         "message %d.\n", ipvs->send_mesg_maxlen);
+       } else if (sync_state == IP_VS_STATE_BACKUP) {
+               dev = __dev_get_by_name(net, ipvs->backup_mcast_ifn);
+               if (!dev)
+                       return -ENODEV;
+
+               ipvs->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", ipvs->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 net *net = sock_net(sk);
+       struct ip_mreqn mreq;
+       struct net_device *dev;
+       int ret;
+
+       memset(&mreq, 0, sizeof(mreq));
+       memcpy(&mreq.imr_multiaddr, addr, sizeof(struct in_addr));
+
+       dev = __dev_get_by_name(net, ifname);
+       if (!dev)
+               return -ENODEV;
+       if (sk->sk_bound_dev_if && dev->ifindex != sk->sk_bound_dev_if)
+               return -EINVAL;
+
+       mreq.imr_ifindex = dev->ifindex;
+
+       rtnl_lock();
+       lock_sock(sk);
+       ret = ip_mc_join_group(sk, &mreq);
+       release_sock(sk);
+       rtnl_unlock();
+
+       return ret;
+}
+
+
+static int bind_mcastif_addr(struct socket *sock, char *ifname)
+{
+       struct net *net = sock_net(sock->sk);
+       struct net_device *dev;
+       __be32 addr;
+       struct sockaddr_in sin;
+
+       dev = __dev_get_by_name(net, ifname);
+       if (!dev)
+               return -ENODEV;
+
+       addr = inet_select_addr(dev, 0, RT_SCOPE_UNIVERSE);
+       if (!addr)
+               pr_err("You probably need to specify IP address on "
+                      "multicast interface.\n");
+
+       IP_VS_DBG(7, "binding socket with (%s) %pI4\n",
+                 ifname, &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(struct net *net, int id)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       /* multicast addr */
+       struct sockaddr_in mcast_addr = {
+               .sin_family             = AF_INET,
+               .sin_port               = cpu_to_be16(IP_VS_SYNC_PORT + id),
+               .sin_addr.s_addr        = cpu_to_be32(IP_VS_SYNC_GROUP),
+       };
+       struct socket *sock;
+       int result;
+
+       /* First create a socket move it to right name space later */
+       result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+       if (result < 0) {
+               pr_err("Error during creation of socket; terminating\n");
+               return ERR_PTR(result);
+       }
+       /*
+        * Kernel sockets that are a part of a namespace, should not
+        * hold a reference to a namespace in order to allow to stop it.
+        * After sk_change_net should be released using sk_release_kernel.
+        */
+       sk_change_net(sock->sk, net);
+       result = set_mcast_if(sock->sk, ipvs->master_mcast_ifn);
+       if (result < 0) {
+               pr_err("Error setting outbound mcast interface\n");
+               goto error;
+       }
+
+       set_mcast_loop(sock->sk, 0);
+       set_mcast_ttl(sock->sk, 1);
+       result = sysctl_sync_sock_size(ipvs);
+       if (result > 0)
+               set_sock_size(sock->sk, 1, result);
+
+       result = bind_mcastif_addr(sock, ipvs->master_mcast_ifn);
+       if (result < 0) {
+               pr_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) {
+               pr_err("Error connecting to the multicast addr\n");
+               goto error;
+       }
+
+       return sock;
+
+error:
+       sk_release_kernel(sock->sk);
+       return ERR_PTR(result);
+}
+
+
+/*
+ *      Set up receiving multicast socket over UDP
+ */
+static struct socket *make_receive_sock(struct net *net, int id)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       /* multicast addr */
+       struct sockaddr_in mcast_addr = {
+               .sin_family             = AF_INET,
+               .sin_port               = cpu_to_be16(IP_VS_SYNC_PORT + id),
+               .sin_addr.s_addr        = cpu_to_be32(IP_VS_SYNC_GROUP),
+       };
+       struct socket *sock;
+       int result;
+
+       /* First create a socket */
+       result = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock);
+       if (result < 0) {
+               pr_err("Error during creation of socket; terminating\n");
+               return ERR_PTR(result);
+       }
+       /*
+        * Kernel sockets that are a part of a namespace, should not
+        * hold a reference to a namespace in order to allow to stop it.
+        * After sk_change_net should be released using sk_release_kernel.
+        */
+       sk_change_net(sock->sk, net);
+       /* it is equivalent to the REUSEADDR option in user-space */
+       sock->sk->sk_reuse = SK_CAN_REUSE;
+       result = sysctl_sync_sock_size(ipvs);
+       if (result > 0)
+               set_sock_size(sock->sk, 0, result);
+
+       result = sock->ops->bind(sock, (struct sockaddr *) &mcast_addr,
+                       sizeof(struct sockaddr));
+       if (result < 0) {
+               pr_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,
+                       ipvs->backup_mcast_ifn);
+       if (result < 0) {
+               pr_err("Error joining to the multicast group\n");
+               goto error;
+       }
+
+       return sock;
+
+error:
+       sk_release_kernel(sock->sk);
+       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 int
+ip_vs_send_sync_msg(struct socket *sock, struct ip_vs_sync_mesg *msg)
+{
+       int msize;
+       int ret;
+
+       msize = ntohs(msg->size);
+
+       ret = ip_vs_send_async(sock, (char *)msg, msize);
+       if (ret >= 0 || ret == -EAGAIN)
+               return ret;
+       pr_err("ip_vs_send_async error %d\n", ret);
+       return 0;
+}
+
+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, MSG_DONTWAIT);
+
+       if (len < 0)
+               return len;
+
+       LeaveFunction(7);
+       return len;
+}
+
+/* Wakeup the master thread for sending */
+static void master_wakeup_work_handler(struct work_struct *work)
+{
+       struct ipvs_master_sync_state *ms =
+               container_of(work, struct ipvs_master_sync_state,
+                            master_wakeup_work.work);
+       struct netns_ipvs *ipvs = ms->ipvs;
+
+       spin_lock_bh(&ipvs->sync_lock);
+       if (ms->sync_queue_len &&
+           ms->sync_queue_delay < IPVS_SYNC_WAKEUP_RATE) {
+               ms->sync_queue_delay = IPVS_SYNC_WAKEUP_RATE;
+               wake_up_process(ms->master_thread);
+       }
+       spin_unlock_bh(&ipvs->sync_lock);
+}
+
+/* Get next buffer to send */
+static inline struct ip_vs_sync_buff *
+next_sync_buff(struct netns_ipvs *ipvs, struct ipvs_master_sync_state *ms)
+{
+       struct ip_vs_sync_buff *sb;
+
+       sb = sb_dequeue(ipvs, ms);
+       if (sb)
+               return sb;
+       /* Do not delay entries in buffer for more than 2 seconds */
+       return get_curr_sync_buff(ipvs, ms, IPVS_SYNC_FLUSH_TIME);
+}
+
+static int sync_thread_master(void *data)
+{
+       struct ip_vs_sync_thread_data *tinfo = data;
+       struct netns_ipvs *ipvs = net_ipvs(tinfo->net);
+       struct ipvs_master_sync_state *ms = &ipvs->ms[tinfo->id];
+       struct sock *sk = tinfo->sock->sk;
+       struct ip_vs_sync_buff *sb;
+
+       pr_info("sync thread started: state = MASTER, mcast_ifn = %s, "
+               "syncid = %d, id = %d\n",
+               ipvs->master_mcast_ifn, ipvs->master_syncid, tinfo->id);
+
+       for (;;) {
+               sb = next_sync_buff(ipvs, ms);
+               if (unlikely(kthread_should_stop()))
+                       break;
+               if (!sb) {
+                       schedule_timeout(IPVS_SYNC_CHECK_PERIOD);
+                       continue;
+               }
+               while (ip_vs_send_sync_msg(tinfo->sock, sb->mesg) < 0) {
+                       /* (Ab)use interruptible sleep to avoid increasing
+                        * the load avg.
+                        */
+                       __wait_event_interruptible(*sk_sleep(sk),
+                                                  sock_writeable(sk) ||
+                                                  kthread_should_stop());
+                       if (unlikely(kthread_should_stop()))
+                               goto done;
+               }
+               ip_vs_sync_buff_release(sb);
+       }
+
+done:
+       __set_current_state(TASK_RUNNING);
+       if (sb)
+               ip_vs_sync_buff_release(sb);
+
+       /* clean up the sync_buff queue */
+       while ((sb = sb_dequeue(ipvs, ms)))
+               ip_vs_sync_buff_release(sb);
+       __set_current_state(TASK_RUNNING);
+
+       /* clean up the current sync_buff */
+       sb = get_curr_sync_buff(ipvs, ms, 0);
+       if (sb)
+               ip_vs_sync_buff_release(sb);
+
+       /* release the sending multicast socket */
+       sk_release_kernel(tinfo->sock->sk);
+       kfree(tinfo);
+
+       return 0;
+}
+
+
+static int sync_thread_backup(void *data)
+{
+       struct ip_vs_sync_thread_data *tinfo = data;
+       struct netns_ipvs *ipvs = net_ipvs(tinfo->net);
+       int len;
+
+       pr_info("sync thread started: state = BACKUP, mcast_ifn = %s, "
+               "syncid = %d, id = %d\n",
+               ipvs->backup_mcast_ifn, ipvs->backup_syncid, tinfo->id);
+
+       while (!kthread_should_stop()) {
+               wait_event_interruptible(*sk_sleep(tinfo->sock->sk),
+                        !skb_queue_empty(&tinfo->sock->sk->sk_receive_queue)
+                        || 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,
+                                       ipvs->recv_mesg_maxlen);
+                       if (len <= 0) {
+                               if (len != -EAGAIN)
+                                       pr_err("receiving message error\n");
+                               break;
+                       }
+
+                       ip_vs_process_message(tinfo->net, tinfo->buf, len);
+               }
+       }
+
+       /* release the sending multicast socket */
+       sk_release_kernel(tinfo->sock->sk);
+       kfree(tinfo->buf);
+       kfree(tinfo);
+
+       return 0;
+}
+
+
+int start_sync_thread(struct net *net, int state, char *mcast_ifn, __u8 syncid)
+{
+       struct ip_vs_sync_thread_data *tinfo;
+       struct task_struct **array = NULL, *task;
+       struct socket *sock;
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       char *name;
+       int (*threadfn)(void *data);
+       int id, count;
+       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_v0));
+
+       if (!ipvs->sync_state) {
+               count = clamp(sysctl_sync_ports(ipvs), 1, IPVS_SYNC_PORTS_MAX);
+               ipvs->threads_mask = count - 1;
+       } else
+               count = ipvs->threads_mask + 1;
+
+       if (state == IP_VS_STATE_MASTER) {
+               if (ipvs->ms)
+                       return -EEXIST;
+
+               strlcpy(ipvs->master_mcast_ifn, mcast_ifn,
+                       sizeof(ipvs->master_mcast_ifn));
+               ipvs->master_syncid = syncid;
+               name = "ipvs-m:%d:%d";
+               threadfn = sync_thread_master;
+       } else if (state == IP_VS_STATE_BACKUP) {
+               if (ipvs->backup_threads)
+                       return -EEXIST;
+
+               strlcpy(ipvs->backup_mcast_ifn, mcast_ifn,
+                       sizeof(ipvs->backup_mcast_ifn));
+               ipvs->backup_syncid = syncid;
+               name = "ipvs-b:%d:%d";
+               threadfn = sync_thread_backup;
+       } else {
+               return -EINVAL;
+       }
+
+       if (state == IP_VS_STATE_MASTER) {
+               struct ipvs_master_sync_state *ms;
+
+               ipvs->ms = kzalloc(count * sizeof(ipvs->ms[0]), GFP_KERNEL);
+               if (!ipvs->ms)
+                       goto out;
+               ms = ipvs->ms;
+               for (id = 0; id < count; id++, ms++) {
+                       INIT_LIST_HEAD(&ms->sync_queue);
+                       ms->sync_queue_len = 0;
+                       ms->sync_queue_delay = 0;
+                       INIT_DELAYED_WORK(&ms->master_wakeup_work,
+                                         master_wakeup_work_handler);
+                       ms->ipvs = ipvs;
+               }
+       } else {
+               array = kzalloc(count * sizeof(struct task_struct *),
+                               GFP_KERNEL);
+               if (!array)
+                       goto out;
+       }
+       set_sync_mesg_maxlen(net, state);
+
+       tinfo = NULL;
+       for (id = 0; id < count; id++) {
+               if (state == IP_VS_STATE_MASTER)
+                       sock = make_send_sock(net, id);
+               else
+                       sock = make_receive_sock(net, id);
+               if (IS_ERR(sock)) {
+                       result = PTR_ERR(sock);
+                       goto outtinfo;
+               }
+               tinfo = kmalloc(sizeof(*tinfo), GFP_KERNEL);
+               if (!tinfo)
+                       goto outsocket;
+               tinfo->net = net;
+               tinfo->sock = sock;
+               if (state == IP_VS_STATE_BACKUP) {
+                       tinfo->buf = kmalloc(ipvs->recv_mesg_maxlen,
+                                            GFP_KERNEL);
+                       if (!tinfo->buf)
+                               goto outtinfo;
+               } else {
+                       tinfo->buf = NULL;
+               }
+               tinfo->id = id;
+
+               task = kthread_run(threadfn, tinfo, name, ipvs->gen, id);
+               if (IS_ERR(task)) {
+                       result = PTR_ERR(task);
+                       goto outtinfo;
+               }
+               tinfo = NULL;
+               if (state == IP_VS_STATE_MASTER)
+                       ipvs->ms[id].master_thread = task;
+               else
+                       array[id] = task;
+       }
+
+       /* mark as active */
+
+       if (state == IP_VS_STATE_BACKUP)
+               ipvs->backup_threads = array;
+       spin_lock_bh(&ipvs->sync_buff_lock);
+       ipvs->sync_state |= state;
+       spin_unlock_bh(&ipvs->sync_buff_lock);
+
+       /* increase the module use count */
+       ip_vs_use_count_inc();
+
+       return 0;
+
+outsocket:
+       sk_release_kernel(sock->sk);
+
+outtinfo:
+       if (tinfo) {
+               sk_release_kernel(tinfo->sock->sk);
+               kfree(tinfo->buf);
+               kfree(tinfo);
+       }
+       count = id;
+       while (count-- > 0) {
+               if (state == IP_VS_STATE_MASTER)
+                       kthread_stop(ipvs->ms[count].master_thread);
+               else
+                       kthread_stop(array[count]);
+       }
+       kfree(array);
+
+out:
+       if (!(ipvs->sync_state & IP_VS_STATE_MASTER)) {
+               kfree(ipvs->ms);
+               ipvs->ms = NULL;
+       }
+       return result;
+}
+
+
+int stop_sync_thread(struct net *net, int state)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+       struct task_struct **array;
+       int id;
+       int retc = -EINVAL;
+
+       IP_VS_DBG(7, "%s(): pid %d\n", __func__, task_pid_nr(current));
+
+       if (state == IP_VS_STATE_MASTER) {
+               if (!ipvs->ms)
+                       return -ESRCH;
+
+               /*
+                * 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_bh(&ipvs->sync_buff_lock);
+               spin_lock(&ipvs->sync_lock);
+               ipvs->sync_state &= ~IP_VS_STATE_MASTER;
+               spin_unlock(&ipvs->sync_lock);
+               spin_unlock_bh(&ipvs->sync_buff_lock);
+
+               retc = 0;
+               for (id = ipvs->threads_mask; id >= 0; id--) {
+                       struct ipvs_master_sync_state *ms = &ipvs->ms[id];
+                       int ret;
+
+                       pr_info("stopping master sync thread %d ...\n",
+                               task_pid_nr(ms->master_thread));
+                       cancel_delayed_work_sync(&ms->master_wakeup_work);
+                       ret = kthread_stop(ms->master_thread);
+                       if (retc >= 0)
+                               retc = ret;
+               }
+               kfree(ipvs->ms);
+               ipvs->ms = NULL;
+       } else if (state == IP_VS_STATE_BACKUP) {
+               if (!ipvs->backup_threads)
+                       return -ESRCH;
+
+               ipvs->sync_state &= ~IP_VS_STATE_BACKUP;
+               array = ipvs->backup_threads;
+               retc = 0;
+               for (id = ipvs->threads_mask; id >= 0; id--) {
+                       int ret;
+
+                       pr_info("stopping backup sync thread %d ...\n",
+                               task_pid_nr(array[id]));
+                       ret = kthread_stop(array[id]);
+                       if (retc >= 0)
+                               retc = ret;
+               }
+               kfree(array);
+               ipvs->backup_threads = NULL;
+       }
+
+       /* decrease the module use count */
+       ip_vs_use_count_dec();
+
+       return retc;
+}
+
+/*
+ * Initialize data struct for each netns
+ */
+int __net_init ip_vs_sync_net_init(struct net *net)
+{
+       struct netns_ipvs *ipvs = net_ipvs(net);
+
+       __mutex_init(&ipvs->sync_mutex, "ipvs->sync_mutex", &__ipvs_sync_key);
+       spin_lock_init(&ipvs->sync_lock);
+       spin_lock_init(&ipvs->sync_buff_lock);
+       return 0;
+}
+
+void ip_vs_sync_net_cleanup(struct net *net)
+{
+       int retc;
+       struct netns_ipvs *ipvs = net_ipvs(net);
+
+       mutex_lock(&ipvs->sync_mutex);
+       retc = stop_sync_thread(net, IP_VS_STATE_MASTER);
+       if (retc && retc != -ESRCH)
+               pr_err("Failed to stop Master Daemon\n");
+
+       retc = stop_sync_thread(net, IP_VS_STATE_BACKUP);
+       if (retc && retc != -ESRCH)
+               pr_err("Failed to stop Backup Daemon\n");
+       mutex_unlock(&ipvs->sync_mutex);
+}