[IPVS] add a sysctl variable to expire quiescent template

The patch is from Horms <horms@vergenet.net>
Signed-off-by: Horms <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_vs.h

@@ -358,6 +358,7 @@ enum {
 	NET_IPV4_VS_EXPIRE_NODEST_CONN=23,
 	NET_IPV4_VS_SYNC_THRESHOLD=24,
 	NET_IPV4_VS_NAT_ICMP_SEND=25,
+	NET_IPV4_VS_EXPIRE_QUIESCENT_TEMPLATE=26,
 	NET_IPV4_VS_LAST
 };
 
@@ -879,6 +880,7 @@ extern int ip_vs_leave(struct ip_vs_service *svc, struct sk_buff *skb,
  */
 extern int sysctl_ip_vs_cache_bypass;
 extern int sysctl_ip_vs_expire_nodest_conn;
+extern int sysctl_ip_vs_expire_quiescent_template;
 extern int sysctl_ip_vs_sync_threshold[2];
 extern int sysctl_ip_vs_nat_icmp_send;
 extern struct ip_vs_stats ip_vs_stats;

net/ipv4/ipvs/ip_vs_conn.c

@@ -453,7 +453,9 @@ int ip_vs_check_template(struct ip_vs_conn *ct)
 	 * Checking the dest server status.
 	 */
 	if ((dest == NULL) ||
-	    !(dest->flags & IP_VS_DEST_F_AVAILABLE)) {
+	    !(dest->flags & IP_VS_DEST_F_AVAILABLE) || 
+	    (sysctl_ip_vs_expire_quiescent_template && 
+	     (atomic_read(&dest->weight) == 0))) {
 		IP_VS_DBG(9, "check_template: dest not available for "
 			  "protocol %s s:%u.%u.%u.%u:%d v:%u.%u.%u.%u:%d "
 			  "-> d:%u.%u.%u.%u:%d\n",

net/ipv4/ipvs/ip_vs_ctl.c

@@ -75,6 +75,7 @@ static int sysctl_ip_vs_amemthresh = 1024;
 static int sysctl_ip_vs_am_droprate = 10;
 int sysctl_ip_vs_cache_bypass = 0;
 int sysctl_ip_vs_expire_nodest_conn = 0;
+int sysctl_ip_vs_expire_quiescent_template = 0;
 int sysctl_ip_vs_sync_threshold[2] = { 3, 50 };
 int sysctl_ip_vs_nat_icmp_send = 0;
 
@@ -1557,6 +1558,14 @@ static struct ctl_table vs_vars[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
+	{
+		.ctl_name	= NET_IPV4_VS_EXPIRE_QUIESCENT_TEMPLATE,
+		.procname	= "expire_quiescent_template",
+		.data		= &sysctl_ip_vs_expire_quiescent_template,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
 	{
 		.ctl_name	= NET_IPV4_VS_SYNC_THRESHOLD,
 		.procname	= "sync_threshold",