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/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;