1 files changed, 115 insertions, 0 deletions
diff --git a/net/ipv4/multipath_rr.c b/net/ipv4/multipath_rr.c
new file mode 100644
index 00000000000..554a8256816
--- /dev/null
+++ b/net/ipv4/multipath_rr.c
@@ -0,0 +1,115 @@
+/*
+ *              Round robin policy for multipath.
+ *
+ *
+ * Version:	$Id: multipath_rr.c,v 1.1.2.2 2004/09/16 07:42:34 elueck Exp $
+ *
+ * Authors:	Einar Lueck <elueck@de.ibm.com><lkml@einar-lueck.de>
+ *
+ *		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.
+ */
+
+#include <linux/config.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/kernel.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/inetdevice.h>
+#include <linux/igmp.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/mroute.h>
+#include <linux/init.h>
+#include <net/ip.h>
+#include <net/protocol.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+#include <net/raw.h>
+#include <linux/notifier.h>
+#include <linux/if_arp.h>
+#include <linux/netfilter_ipv4.h>
+#include <net/ipip.h>
+#include <net/checksum.h>
+#include <net/ip_mp_alg.h>
+
+#define MULTIPATH_MAX_CANDIDATES 40
+
+static struct rtable* last_used = NULL;
+
+static void rr_remove(struct rtable *rt)
+{
+	if (last_used == rt)
+		last_used = NULL;
+}
+
+static void rr_select_route(const struct flowi *flp,
+			    struct rtable *first, struct rtable **rp)
+{
+	struct rtable *nh, *result, *min_use_cand = NULL;
+	int min_use = -1;
+
+	/* if necessary and possible utilize the old alternative */
+	if ((flp->flags & FLOWI_FLAG_MULTIPATHOLDROUTE) != 0 &&
+	    last_used != NULL) {
+		result = last_used;
+		goto out;
+	}
+
+	/* 1. make sure all alt. nexthops have the same GC related data
+	 * 2. determine the new candidate to be returned
+	 */
+	result = NULL;
+	for (nh = rcu_dereference(first); nh;
+ 	     nh = rcu_dereference(nh->u.rt_next)) {
+		if ((nh->u.dst.flags & DST_BALANCED) != 0 &&
+		    multipath_comparekeys(&nh->fl, flp)) {
+			nh->u.dst.lastuse = jiffies;
+
+			if (min_use == -1 || nh->u.dst.__use < min_use) {
+				min_use = nh->u.dst.__use;
+				min_use_cand = nh;
+			}
+		}
+	}
+	result = min_use_cand;
+	if (!result)
+		result = first;
+
+out:
+	last_used = result;
+	result->u.dst.__use++;
+	*rp = result;
+}
+
+static struct ip_mp_alg_ops rr_ops = {
+	.mp_alg_select_route	=	rr_select_route,
+	.mp_alg_remove		=	rr_remove,
+};
+
+static int __init rr_init(void)
+{
+	return multipath_alg_register(&rr_ops, IP_MP_ALG_RR);
+}
+
+static void __exit rr_exit(void)
+{
+	multipath_alg_unregister(&rr_ops, IP_MP_ALG_RR);
+}
+
+module_init(rr_init);
+module_exit(rr_exit);