3 files changed, 98 insertions, 0 deletions

diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
index 3b6929dec748..b32fb0dbe237 100644
--- a/net/netfilter/ipvs/Kconfig
+++ b/net/netfilter/ipvs/Kconfig
@@ -162,6 +162,17 @@ config  IP_VS_FO
 	  If you want to compile it in kernel, say Y. To compile it as a
 	  module, choose M here. If unsure, say N.
 
+config  IP_VS_OVF
+	tristate "weighted overflow scheduling"
+	---help---
+	  The weighted overflow scheduling algorithm directs network
+	  connections to the server with the highest weight that is
+	  currently available and overflows to the next when active
+	  connections exceed the node's weight.
+
+	  If you want to compile it in kernel, say Y. To compile it as a
+	  module, choose M here. If unsure, say N.
+
 config	IP_VS_LBLC
 	tristate "locality-based least-connection scheduling"
 	---help---
diff --git a/net/netfilter/ipvs/Makefile b/net/netfilter/ipvs/Makefile
index 38b2723b2e3d..67f3f4389602 100644
--- a/net/netfilter/ipvs/Makefile
+++ b/net/netfilter/ipvs/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_IP_VS_WRR) += ip_vs_wrr.o
 obj-$(CONFIG_IP_VS_LC) += ip_vs_lc.o
 obj-$(CONFIG_IP_VS_WLC) += ip_vs_wlc.o
 obj-$(CONFIG_IP_VS_FO) += ip_vs_fo.o
+obj-$(CONFIG_IP_VS_OVF) += ip_vs_ovf.o
 obj-$(CONFIG_IP_VS_LBLC) += ip_vs_lblc.o
 obj-$(CONFIG_IP_VS_LBLCR) += ip_vs_lblcr.o
 obj-$(CONFIG_IP_VS_DH) += ip_vs_dh.o
diff --git a/net/netfilter/ipvs/ip_vs_ovf.c b/net/netfilter/ipvs/ip_vs_ovf.c
new file mode 100644
index 000000000000..f7d62c3b7329
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_ovf.c
@@ -0,0 +1,86 @@
+/*
+ * IPVS:        Overflow-Connection Scheduling module
+ *
+ * Authors:     Raducu Deaconu <rhadoo_io@yahoo.com>
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ * Scheduler implements "overflow" loadbalancing according to number of active
+ * connections , will keep all conections to the node with the highest weight
+ * and overflow to the next node if the number of connections exceeds the node's
+ * weight.
+ * Note that this scheduler might not be suitable for UDP because it only uses
+ * active connections
+ *
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <net/ip_vs.h>
+
+/* OVF Connection scheduling  */
+static struct ip_vs_dest *
+ip_vs_ovf_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
+		   struct ip_vs_iphdr *iph)
+{
+	struct ip_vs_dest *dest, *h = NULL;
+	int hw = 0, w;
+
+	IP_VS_DBG(6, "ip_vs_ovf_schedule(): Scheduling...\n");
+	/* select the node with highest weight, go to next in line if active
+	* connections exceed weight
+	*/
+	list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
+		w = atomic_read(&dest->weight);
+		if ((dest->flags & IP_VS_DEST_F_OVERLOAD) ||
+		    atomic_read(&dest->activeconns) > w ||
+		    w == 0)
+			continue;
+		if (!h || w > hw) {
+			h = dest;
+			hw = w;
+		}
+	}
+
+	if (h) {
+		IP_VS_DBG_BUF(6, "OVF: server %s:%u active %d w %d\n",
+			      IP_VS_DBG_ADDR(h->af, &h->addr),
+			      ntohs(h->port),
+			      atomic_read(&h->activeconns),
+			      atomic_read(&h->weight));
+		return h;
+	}
+
+	ip_vs_scheduler_err(svc, "no destination available");
+	return NULL;
+}
+
+static struct ip_vs_scheduler ip_vs_ovf_scheduler = {
+	.name =			"ovf",
+	.refcnt =		ATOMIC_INIT(0),
+	.module =		THIS_MODULE,
+	.n_list =		LIST_HEAD_INIT(ip_vs_ovf_scheduler.n_list),
+	.schedule =		ip_vs_ovf_schedule,
+};
+
+static int __init ip_vs_ovf_init(void)
+{
+	return register_ip_vs_scheduler(&ip_vs_ovf_scheduler);
+}
+
+static void __exit ip_vs_ovf_cleanup(void)
+{
+	unregister_ip_vs_scheduler(&ip_vs_ovf_scheduler);
+	synchronize_rcu();
+}
+
+module_init(ip_vs_ovf_init);
+module_exit(ip_vs_ovf_cleanup);
+MODULE_LICENSE("GPL");