ipv4: use separate genid for next hop exceptions
commit 13d82bf5 (ipv4: Fix flushing of cached routing informations)
added the support to flush learned pmtu information.
However, using rt_genid is quite heavy as it is bumped on route
add/change and multicast events amongst other places. These can
happen quite often, especially if using dynamic routing protocols.
While this is ok with routes (as they are just recreated locally),
the pmtu information is learned from remote systems and the icmp
notification can come with long delays. It is worthy to have separate
genid to avoid excessive pmtu resets.
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index e49db91..44424e9 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -51,6 +51,7 @@
struct fib_nh_exception {
struct fib_nh_exception __rcu *fnhe_next;
+ int fnhe_genid;
__be32 fnhe_daddr;
u32 fnhe_pmtu;
__be32 fnhe_gw;
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index b176978..495bc57 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -118,6 +118,7 @@
struct netns_ipvs *ipvs;
struct sock *diag_nlsk;
atomic_t rt_genid;
+ atomic_t fnhe_genid;
};
/*
@@ -340,4 +341,14 @@
atomic_inc(&net->rt_genid);
}
+static inline int fnhe_genid(struct net *net)
+{
+ return atomic_read(&net->fnhe_genid);
+}
+
+static inline void fnhe_genid_bump(struct net *net)
+{
+ atomic_inc(&net->fnhe_genid);
+}
+
#endif /* __NET_NET_NAMESPACE_H */
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a4082be..403e283 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -658,6 +658,7 @@
fnhe->fnhe_next = hash->chain;
rcu_assign_pointer(hash->chain, fnhe);
}
+ fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev));
fnhe->fnhe_daddr = daddr;
fnhe->fnhe_gw = gw;
fnhe->fnhe_pmtu = pmtu;
@@ -1236,8 +1237,11 @@
spin_lock_bh(&fnhe_lock);
if (daddr == fnhe->fnhe_daddr) {
+ int genid = fnhe_genid(dev_net(rt->dst.dev));
struct rtable *orig = rcu_dereference(fnhe->fnhe_rth);
- if (orig && rt_is_expired(orig)) {
+
+ if (fnhe->fnhe_genid != genid) {
+ fnhe->fnhe_genid = genid;
fnhe->fnhe_gw = 0;
fnhe->fnhe_pmtu = 0;
fnhe->fnhe_expires = 0;
@@ -2443,8 +2447,11 @@
void __user *buffer,
size_t *lenp, loff_t *ppos)
{
+ struct net *net = (struct net *)__ctl->extra1;
+
if (write) {
- rt_cache_flush((struct net *)__ctl->extra1);
+ rt_cache_flush(net);
+ fnhe_genid_bump(net);
return 0;
}
@@ -2619,6 +2626,7 @@
static __net_init int rt_genid_init(struct net *net)
{
atomic_set(&net->rt_genid, 0);
+ atomic_set(&net->fnhe_genid, 0);
get_random_bytes(&net->ipv4.dev_addr_genid,
sizeof(net->ipv4.dev_addr_genid));
return 0;
