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/include/net/ip_fib.h b/include/net/ip_fib.h
index 5697ace..e9ee1ca 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -18,6 +18,7 @@
#include <net/flow.h>
#include <linux/seq_file.h>
+#include <linux/rcupdate.h>
#include <net/fib_rules.h>
#include <net/inetpeer.h>
@@ -46,6 +47,22 @@
struct fib_info;
+struct fib_nh_exception {
+ struct fib_nh_exception __rcu *fnhe_next;
+ __be32 fnhe_daddr;
+ u32 fnhe_pmtu;
+ u32 fnhe_gw;
+ unsigned long fnhe_expires;
+ unsigned long fnhe_stamp;
+};
+
+struct fnhe_hash_bucket {
+ struct fib_nh_exception __rcu *chain;
+};
+
+#define FNHE_HASH_SIZE 2048
+#define FNHE_RECLAIM_DEPTH 5
+
struct fib_nh {
struct net_device *nh_dev;
struct hlist_node nh_hash;
@@ -63,6 +80,7 @@
__be32 nh_gw;
__be32 nh_saddr;
int nh_saddr_genid;
+ struct fnhe_hash_bucket *nh_exceptions;
};
/*