[IPV4]: Make multipath algs into true drivers.

This also makes them configurable on a per-route
basis via rtnetlink route attributes.

Based upon suggestions from Thomas Graf and Alexey
Kuznetsov.

Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 105 insertions, 80 deletions

diff --git a/include/linux/ip_mp_alg.h b/include/linux/ip_mp_alg.h
new file mode 100644
index 000000000000..e234e2008f5d
--- /dev/null
+++ b/include/linux/ip_mp_alg.h
@@ -0,0 +1,22 @@
+/* ip_mp_alg.h: IPV4 multipath algorithm support, user-visible values.
+ *
+ * Copyright (C) 2004, 2005 Einar Lueck <elueck@de.ibm.com>
+ * Copyright (C) 2005 David S. Miller <davem@davemloft.net>
+ */
+
+#ifndef _LINUX_IP_MP_ALG_H
+#define _LINUX_IP_MP_ALG_H
+
+enum ip_mp_alg {
+	IP_MP_ALG_NONE,
+	IP_MP_ALG_RR,
+	IP_MP_ALG_DRR,
+	IP_MP_ALG_RANDOM,
+	IP_MP_ALG_WRANDOM,
+	__IP_MP_ALG_MAX
+};
+
+#define IP_MP_ALG_MAX (__IP_MP_ALG_MAX - 1)
+
+#endif /* _LINUX_IP_MP_ALG_H */
+
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index b3fec31e7e6f..6d6b2eae47e0 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -250,6 +250,7 @@ enum rtattr_type_t
 	RTA_FLOW,
 	RTA_CACHEINFO,
 	RTA_SESSION,
+	RTA_MP_ALGO,
 	__RTA_MAX
 };
 
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index c03741febe66..e5a5f6b62f88 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -37,6 +37,7 @@ struct kern_rta {
 	u32		*rta_flow;
 	struct rta_cacheinfo *rta_ci;
 	struct rta_session *rta_sess;
+	u32		*rta_mp_alg;
 };
 
 struct fib_info;
@@ -81,6 +82,9 @@ struct fib_info {
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	int			fib_power;
 #endif
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
+	u32			fib_mp_alg;
+#endif
 	struct fib_nh		fib_nh[0];
 #define fib_dev		fib_nh[0].nh_dev
 };
@@ -95,7 +99,7 @@ struct fib_result {
 	unsigned char	nh_sel;
 	unsigned char	type;
 	unsigned char	scope;
-#ifdef CONFIG_IP_ROUTE_MULTIPATH_WRANDOM
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 	__u32           network;
 	__u32           netmask;
 #endif
@@ -123,10 +127,10 @@ struct fib_result {
 #define FIB_RES_DEV(res)		(FIB_RES_NH(res).nh_dev)
 #define FIB_RES_OIF(res)		(FIB_RES_NH(res).nh_oif)
 
-#ifdef CONFIG_IP_ROUTE_MULTIPATH_WRANDOM
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
 #define FIB_RES_NETWORK(res)		((res).network)
 #define FIB_RES_NETMASK(res)	        ((res).netmask)
-#else /* CONFIG_IP_ROUTE_MULTIPATH_WRANDOM */
+#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
 #define FIB_RES_NETWORK(res)		(0)
 #define FIB_RES_NETMASK(res)	        (0)
 #endif /* CONFIG_IP_ROUTE_MULTIPATH_WRANDOM */
diff --git a/include/net/ip_mp_alg.h b/include/net/ip_mp_alg.h
index 60cebf0130a8..9431df22782c 100644
--- a/include/net/ip_mp_alg.h
+++ b/include/net/ip_mp_alg.h
@@ -4,13 +4,84 @@
  * Copyright (C) 2005 David S. Miller <davem@davemloft.net>
  */
 
-#ifndef _IP_MP_ALG_H
-#define _IP_MP_ALG_H
+#ifndef _NET_IP_MP_ALG_H
+#define _NET_IP_MP_ALG_H
 
 #include <linux/config.h>
+#include <linux/ip_mp_alg.h>
 #include <net/flow.h>
+#include <net/route.h>
 
-static int inline multipath_comparekeys(const struct flowi *flp1,
+struct fib_nh;
+
+struct ip_mp_alg_ops {
+	void	(*mp_alg_select_route)(const struct flowi *flp,
+				       struct rtable *rth, struct rtable **rp);
+	void	(*mp_alg_flush)(void);
+	void	(*mp_alg_set_nhinfo)(__u32 network, __u32 netmask,
+				     unsigned char prefixlen,
+				     const struct fib_nh *nh);
+	void	(*mp_alg_remove)(struct rtable *rth);
+};
+
+extern int multipath_alg_register(struct ip_mp_alg_ops *, enum ip_mp_alg);
+extern void multipath_alg_unregister(struct ip_mp_alg_ops *, enum ip_mp_alg);
+
+extern struct ip_mp_alg_ops *ip_mp_alg_table[];
+
+static inline int multipath_select_route(const struct flowi *flp,
+					 struct rtable *rth,
+					 struct rtable **rp)
+{
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
+	struct ip_mp_alg_ops *ops = ip_mp_alg_table[rth->rt_multipath_alg];
+
+	if (ops && (rth->u.dst.flags & DST_BALANCED)) {
+		ops->mp_alg_select_route(flp, rth, rp);
+		return 1;
+	}
+#endif
+	return 0;
+}
+
+static inline void multipath_flush(void)
+{
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
+	int i;
+
+	for (i = IP_MP_ALG_NONE; i <= IP_MP_ALG_MAX; i++) {
+		struct ip_mp_alg_ops *ops = ip_mp_alg_table[i];
+
+		if (ops)
+			ops->mp_alg_flush();
+	}
+#endif
+}
+
+static inline void multipath_set_nhinfo(struct rtable *rth,
+					__u32 network, __u32 netmask,
+					unsigned char prefixlen,
+					const struct fib_nh *nh)
+{
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
+	struct ip_mp_alg_ops *ops = ip_mp_alg_table[rth->rt_multipath_alg];
+
+	if (ops)
+		ops->mp_alg_set_nhinfo(network, netmask, prefixlen, nh);
+#endif
+}
+
+static inline void multipath_remove(struct rtable *rth)
+{
+#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
+	struct ip_mp_alg_ops *ops = ip_mp_alg_table[rth->rt_multipath_alg];
+
+	if (ops && (rth->u.dst.flags & DST_BALANCED))
+		ops->mp_alg_remove(rth);
+#endif
+}
+
+static inline int multipath_comparekeys(const struct flowi *flp1,
 					const struct flowi *flp2)
 {
 	return flp1->fl4_dst == flp2->fl4_dst &&
@@ -23,4 +94,4 @@ static int inline multipath_comparekeys(const struct flowi *flp1,
 		  (IPTOS_RT_MASK | RTO_ONLINK));
 }
 
-#endif /* _IP_MP_ALG_H */
+#endif /* _NET_IP_MP_ALG_H */
diff --git a/include/net/route.h b/include/net/route.h
index 4e3b782175d6..22da7579d5de 100644
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -202,77 +202,4 @@ static inline struct inet_peer *rt_get_peer(struct rtable *rt)
 	return rt->peer;
 }
 
-#ifdef CONFIG_IP_ROUTE_MULTIPATH_WRANDOM
-extern void __multipath_flush(void);
-static inline void multipath_flush(void)
-{
-	__multipath_flush();
-}
-#else /* CONFIG_IP_ROUTE_MULTIPATH_WRANDOM */
-static inline void multipath_flush(void)
-{
-}
-#endif /* CONFIG_IP_ROUTE_MULTIPATH_WRANDOM */
-
-#ifdef CONFIG_IP_ROUTE_MULTIPATH_WRANDOM
-extern void __multipath_set_nhinfo(__u32 network,
-				   __u32 netmask,
-				   unsigned char prefixlen,
-				   const struct fib_nh* nh);
-static inline void multipath_set_nhinfo(__u32 network,
-					__u32 netmask,
-					unsigned char prefixlen,
-					const struct fib_nh* nh)
-{
-	__multipath_set_nhinfo(network, netmask, prefixlen, nh);
-}
-#else
-static inline void multipath_set_nhinfo(__u32 network,
-					__u32 netmask,
-					unsigned char prefixlen,
-					const struct fib_nh* nh)
-{
-}
-#endif
-
-
-
-#if defined(CONFIG_IP_ROUTE_MULTIPATH_RR) || defined(CONFIG_IP_ROUTE_MULTIPATH_DRR)
-extern void __multipath_remove(struct rtable *rt);
-static inline void multipath_remove(struct rtable *rt)
-{
-	if ( rt->u.dst.flags & DST_BALANCED )
-		__multipath_remove(rt);
-}
-#else /* CONFIG_IP_ROUTE_MULTIPATH_RR || CONFIG_IP_ROUTE_MULTIPATH_DRR */
-static inline void multipath_remove(struct rtable *rt)
-{
-}
-#endif /* CONFIG_IP_ROUTE_MULTIPATH_RR || CONFIG_IP_ROUTE_MULTIPATH_DRR */
-
-
-#ifdef CONFIG_IP_ROUTE_MULTIPATH_CACHED
-extern void __multipath_selectroute(const struct flowi *flp,
-				    struct rtable *rth,
-				    struct rtable **rp);
-static inline int multipath_selectroute(const struct flowi *flp,
-					struct rtable *rth,
-					struct rtable **rp)
-{
-	if (rth->u.dst.flags & DST_BALANCED) {
-		__multipath_selectroute(flp, rth, rp);
-		return 1;
-	} else {
-		return 0;
-	}
-}
-#else /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
-static inline int multipath_selectroute(const struct flowi *flp,
-					struct rtable *rth,
-					struct rtable **rp)
-{
-	return 0;
-}
-#endif /* CONFIG_IP_ROUTE_MULTIPATH_CACHED */
-
 #endif	/* _ROUTE_H */