ipv4: Add FIB nexthop exceptions.
In a regime where we have subnetted route entries, we need a way to
store persistent storage about destination specific learned values
such as redirects and PMTU values.
This is implemented here via nexthop exceptions.
The initial implementation is a 2048 entry hash table with relaiming
starting at chain length 5. A more sophisticated scheme can be
devised if that proves necessary.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index d71bfbd..1e09852 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -140,6 +140,27 @@
},
};
+static void free_nh_exceptions(struct fib_nh *nh)
+{
+ struct fnhe_hash_bucket *hash = nh->nh_exceptions;
+ int i;
+
+ for (i = 0; i < FNHE_HASH_SIZE; i++) {
+ struct fib_nh_exception *fnhe;
+
+ fnhe = rcu_dereference(hash[i].chain);
+ while (fnhe) {
+ struct fib_nh_exception *next;
+
+ next = rcu_dereference(fnhe->fnhe_next);
+ kfree(fnhe);
+
+ fnhe = next;
+ }
+ }
+ kfree(hash);
+}
+
/* Release a nexthop info record */
static void free_fib_info_rcu(struct rcu_head *head)
{
@@ -148,6 +169,8 @@
change_nexthops(fi) {
if (nexthop_nh->nh_dev)
dev_put(nexthop_nh->nh_dev);
+ if (nexthop_nh->nh_exceptions)
+ free_nh_exceptions(nexthop_nh);
} endfor_nexthops(fi);
release_net(fi->fib_net);