xfrm: cache bundles instead of policies for outgoing flows

__xfrm_lookup() is called for each packet transmitted out of
system. The xfrm_find_bundle() does a linear search which can
kill system performance depending on how many bundles are
required per policy.

This modifies __xfrm_lookup() to store bundles directly in
the flow cache. If we did not get a hit, we just create a new
bundle instead of doing slow search. This means that we can now
get multiple xfrm_dst's for same flow (on per-cpu basis).

Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -267,7 +267,6 @@ struct xfrm_policy_afinfo {
 					       xfrm_address_t *saddr,
 					       xfrm_address_t *daddr);
 	int			(*get_saddr)(struct net *net, xfrm_address_t *saddr, xfrm_address_t *daddr);
-	struct dst_entry	*(*find_bundle)(struct flowi *fl, struct xfrm_policy *policy);
 	void			(*decode_session)(struct sk_buff *skb,
 						  struct flowi *fl,
 						  int reverse);
@@ -483,13 +482,13 @@ struct xfrm_policy {
 	struct timer_list	timer;
 
 	struct flow_cache_object flo;
+	atomic_t		genid;
 	u32			priority;
 	u32			index;
 	struct xfrm_mark	mark;
 	struct xfrm_selector	selector;
 	struct xfrm_lifetime_cfg lft;
 	struct xfrm_lifetime_cur curlft;
-	struct dst_entry       *bundles;
 	struct xfrm_policy_walk_entry walk;
 	u8			type;
 	u8			action;
@@ -879,11 +878,15 @@ struct xfrm_dst {
 		struct rt6_info		rt6;
 	} u;
 	struct dst_entry *route;
+	struct flow_cache_object flo;
+	struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
+	int num_pols, num_xfrms;
 #ifdef CONFIG_XFRM_SUB_POLICY
 	struct flowi *origin;
 	struct xfrm_selector *partner;
 #endif
-	u32 genid;
+	u32 xfrm_genid;
+	u32 policy_genid;
 	u32 route_mtu_cached;
 	u32 child_mtu_cached;
 	u32 route_cookie;
@@ -893,6 +896,7 @@ struct xfrm_dst {
 #ifdef CONFIG_XFRM
 static inline void xfrm_dst_destroy(struct xfrm_dst *xdst)
 {
+	xfrm_pols_put(xdst->pols, xdst->num_pols);
 	dst_release(xdst->route);
 	if (likely(xdst->u.dst.xfrm))
 		xfrm_state_put(xdst->u.dst.xfrm);

net/ipv4/xfrm4_policy.c

@@ -59,27 +59,6 @@ static int xfrm4_get_saddr(struct net *net,
 	return 0;
 }
 
-static struct dst_entry *
-__xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
-{
-	struct dst_entry *dst;
-
-	read_lock_bh(&policy->lock);
-	for (dst = policy->bundles; dst; dst = dst->next) {
-		struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
-		if (xdst->u.rt.fl.oif == fl->oif &&	/*XXX*/
-		    xdst->u.rt.fl.fl4_dst == fl->fl4_dst &&
-		    xdst->u.rt.fl.fl4_src == fl->fl4_src &&
-		    xdst->u.rt.fl.fl4_tos == fl->fl4_tos &&
-		    xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) {
-			dst_clone(dst);
-			break;
-		}
-	}
-	read_unlock_bh(&policy->lock);
-	return dst;
-}
-
 static int xfrm4_get_tos(struct flowi *fl)
 {
 	return fl->fl4_tos;
@@ -259,7 +238,6 @@ static struct xfrm_policy_afinfo xfrm4_policy_afinfo = {
 	.dst_ops =		&xfrm4_dst_ops,
 	.dst_lookup =		xfrm4_dst_lookup,
 	.get_saddr =		xfrm4_get_saddr,
-	.find_bundle = 		__xfrm4_find_bundle,
 	.decode_session =	_decode_session4,
 	.get_tos =		xfrm4_get_tos,
 	.init_path =		xfrm4_init_path,

net/ipv6/xfrm6_policy.c

@@ -67,36 +67,6 @@ static int xfrm6_get_saddr(struct net *net,
 	return 0;
 }
 
-static struct dst_entry *
-__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
-{
-	struct dst_entry *dst;
-
-	/* Still not clear if we should set fl->fl6_{src,dst}... */
-	read_lock_bh(&policy->lock);
-	for (dst = policy->bundles; dst; dst = dst->next) {
-		struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
-		struct in6_addr fl_dst_prefix, fl_src_prefix;
-
-		ipv6_addr_prefix(&fl_dst_prefix,
-				 &fl->fl6_dst,
-				 xdst->u.rt6.rt6i_dst.plen);
-		ipv6_addr_prefix(&fl_src_prefix,
-				 &fl->fl6_src,
-				 xdst->u.rt6.rt6i_src.plen);
-		if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
-		    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
-		    xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
-				   (xdst->u.rt6.rt6i_dst.plen != 128 ||
-				    xdst->u.rt6.rt6i_src.plen != 128))) {
-			dst_clone(dst);
-			break;
-		}
-	}
-	read_unlock_bh(&policy->lock);
-	return dst;
-}
-
 static int xfrm6_get_tos(struct flowi *fl)
 {
 	return 0;
@@ -291,7 +261,6 @@ static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 	.dst_ops =		&xfrm6_dst_ops,
 	.dst_lookup =		xfrm6_dst_lookup,
 	.get_saddr = 		xfrm6_get_saddr,
-	.find_bundle =		__xfrm6_find_bundle,
 	.decode_session =	_decode_session6,
 	.get_tos =		xfrm6_get_tos,
 	.init_path =		xfrm6_init_path,