[XFRM]: Hash policies when non-prefixed.
This idea is from Alexey Kuznetsov.
It is common for policies to be non-prefixed. And for
that case we can optimize lookups, insert, etc. quite
a bit.
For each direction, we have a dynamically sized policy
hash table for non-prefixed policies. We also have a
hash table on policy->index.
For prefixed policies, we have a list per-direction which
we will consult on lookups when a non-prefix hashtable
lookup fails.
This still isn't as efficient as I would like it. There
are four immediate problems:
1) Lots of excessive refcounting, which can be fixed just
like xfrm_state was
2) We do 2 hash probes on insert, one to look for dups and
one to allocate a unique policy->index. Althought I wonder
how much this matters since xfrm_state inserts do up to
3 hash probes and that seems to perform fine.
3) xfrm_policy_insert() is very complex because of the priority
ordering and entry replacement logic.
4) Lots of counter bumping, in addition to policy refcounts,
in the form of xfrm_policy_count[]. This is merely used
to let code path(s) know that some IPSEC rules exist. So
this count is indexed per-direction, maybe that is overkill.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index c7870b6..0acabf2 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -331,7 +331,8 @@
struct xfrm_policy
{
struct xfrm_policy *next;
- struct list_head list;
+ struct hlist_node bydst;
+ struct hlist_node byidx;
/* This lock only affects elements except for entry. */
rwlock_t lock;
@@ -385,21 +386,7 @@
extern int xfrm_register_km(struct xfrm_mgr *km);
extern int xfrm_unregister_km(struct xfrm_mgr *km);
-
-extern struct xfrm_policy *xfrm_policy_list[XFRM_POLICY_MAX*2];
-#ifdef CONFIG_XFRM_SUB_POLICY
-extern struct xfrm_policy *xfrm_policy_list_sub[XFRM_POLICY_MAX*2];
-
-static inline int xfrm_policy_lists_empty(int dir)
-{
- return (!xfrm_policy_list[dir] && !xfrm_policy_list_sub[dir]);
-}
-#else
-static inline int xfrm_policy_lists_empty(int dir)
-{
- return (!xfrm_policy_list[dir]);
-}
-#endif
+extern unsigned int xfrm_policy_count[XFRM_POLICY_MAX*2];
static inline void xfrm_pol_hold(struct xfrm_policy *policy)
{
@@ -678,7 +665,7 @@
if (sk && sk->sk_policy[XFRM_POLICY_IN])
return __xfrm_policy_check(sk, dir, skb, family);
- return (xfrm_policy_lists_empty(dir) && !skb->sp) ||
+ return (!xfrm_policy_count[dir] && !skb->sp) ||
(skb->dst->flags & DST_NOPOLICY) ||
__xfrm_policy_check(sk, dir, skb, family);
}
@@ -698,7 +685,7 @@
static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
- return xfrm_policy_lists_empty(XFRM_POLICY_OUT) ||
+ return !xfrm_policy_count[XFRM_POLICY_OUT] ||
(skb->dst->flags & DST_NOXFRM) ||
__xfrm_route_forward(skb, family);
}