[IPSEC]: Perform SA switchover immediately.

When we insert a new xfrm_state which potentially
subsumes an existing one, make sure all cached
bundles are flushed so that the new SA is used
immediately.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/xfrm.h

@@ -890,6 +890,7 @@ struct xfrm_state * xfrm_find_acq(u8 mode, u32 reqid, u8 proto,
 extern void xfrm_policy_flush(void);
 extern int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol);
 extern int xfrm_flush_bundles(void);
+extern void xfrm_flush_all_bundles(void);
 extern int xfrm_bundle_ok(struct xfrm_dst *xdst, struct flowi *fl, int family);
 extern void xfrm_init_pmtu(struct dst_entry *dst);
 

net/xfrm/xfrm_policy.c

@@ -1014,13 +1014,12 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
 }
 EXPORT_SYMBOL(__xfrm_route_forward);
 
-/* Optimize later using cookies and generation ids. */
-
 static struct dst_entry *xfrm_dst_check(struct dst_entry *dst, u32 cookie)
 {
-	if (!stale_bundle(dst))
-		return dst;
-
+	/* If it is marked obsolete, which is how we even get here,
+	 * then we have purged it from the policy bundle list and we
+	 * did that for a good reason.
+	 */
 	return NULL;
 }
 
@@ -1104,6 +1103,16 @@ int xfrm_flush_bundles(void)
 	return 0;
 }
 
+static int always_true(struct dst_entry *dst)
+{
+	return 1;
+}
+
+void xfrm_flush_all_bundles(void)
+{
+	xfrm_prune_bundles(always_true);
+}
+
 void xfrm_init_pmtu(struct dst_entry *dst)
 {
 	do {

net/xfrm/xfrm_state.c

@@ -431,6 +431,8 @@ void xfrm_state_insert(struct xfrm_state *x)
 	spin_lock_bh(&xfrm_state_lock);
 	__xfrm_state_insert(x);
 	spin_unlock_bh(&xfrm_state_lock);
+
+	xfrm_flush_all_bundles();
 }
 EXPORT_SYMBOL(xfrm_state_insert);
 
@@ -478,6 +480,9 @@ out:
 	spin_unlock_bh(&xfrm_state_lock);
 	xfrm_state_put_afinfo(afinfo);
 
+	if (!err)
+		xfrm_flush_all_bundles();
+
 	if (x1) {
 		xfrm_state_delete(x1);
 		xfrm_state_put(x1);