Commit 4895c771 authored by David S. Miller's avatar David S. Miller

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: default avatarDavid S. Miller <davem@davemloft.net>
parent 6700c270
......@@ -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_config {
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 @@ struct fib_nh {
__be32 nh_gw;
__be32 nh_saddr;
int nh_saddr_genid;
struct fnhe_hash_bucket *nh_exceptions;
};
/*
......
......@@ -140,6 +140,27 @@ const struct fib_prop fib_props[RTN_MAX + 1] = {
},
};
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 @@ static void free_fib_info_rcu(struct rcu_head *head)
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);
......
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