Merge tag 'ipvs-for-v4.8' of https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs-next

Simon Horman says:

====================
IPVS Updates for v4.8

please consider these enhancements to the IPVS. This alters the behaviour
of the "least connection" schedulers such that pre-established connections
are included in the active connection count. This avoids overloading
servers when a large number of new connections arrive in a short space of
time - e.g. when clients reconnect after a node or network failure.
====================
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/ipvs/ip_vs_proto_tcp.c

@@ -395,6 +395,20 @@ static const char *const tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
 	[IP_VS_TCP_S_LAST]		=	"BUG!",
 };
 
+static const bool tcp_state_active_table[IP_VS_TCP_S_LAST] = {
+	[IP_VS_TCP_S_NONE]		=	false,
+	[IP_VS_TCP_S_ESTABLISHED]	=	true,
+	[IP_VS_TCP_S_SYN_SENT]		=	true,
+	[IP_VS_TCP_S_SYN_RECV]		=	true,
+	[IP_VS_TCP_S_FIN_WAIT]		=	false,
+	[IP_VS_TCP_S_TIME_WAIT]		=	false,
+	[IP_VS_TCP_S_CLOSE]		=	false,
+	[IP_VS_TCP_S_CLOSE_WAIT]	=	false,
+	[IP_VS_TCP_S_LAST_ACK]		=	false,
+	[IP_VS_TCP_S_LISTEN]		=	false,
+	[IP_VS_TCP_S_SYNACK]		=	true,
+};
+
 #define sNO IP_VS_TCP_S_NONE
 #define sES IP_VS_TCP_S_ESTABLISHED
 #define sSS IP_VS_TCP_S_SYN_SENT
@@ -418,6 +432,13 @@ static const char * tcp_state_name(int state)
 	return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
 }
 
+static bool tcp_state_active(int state)
+{
+	if (state >= IP_VS_TCP_S_LAST)
+		return false;
+	return tcp_state_active_table[state];
+}
+
 static struct tcp_states_t tcp_states [] = {
 /*	INPUT */
 /*        sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA	*/
@@ -540,12 +561,12 @@ set_tcp_state(struct ip_vs_proto_data *pd, struct ip_vs_conn *cp,
 
 		if (dest) {
 			if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
-			    (new_state != IP_VS_TCP_S_ESTABLISHED)) {
+			    !tcp_state_active(new_state)) {
 				atomic_dec(&dest->activeconns);
 				atomic_inc(&dest->inactconns);
 				cp->flags |= IP_VS_CONN_F_INACTIVE;
 			} else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
-				   (new_state == IP_VS_TCP_S_ESTABLISHED)) {
+				   tcp_state_active(new_state)) {
 				atomic_inc(&dest->activeconns);
 				atomic_dec(&dest->inactconns);
 				cp->flags &= ~IP_VS_CONN_F_INACTIVE;