From ee9a8f7ab2edf801b8b514c310455c94acc232f6 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Mon, 8 Oct 2012 00:56:54 +0000 Subject: [PATCH] ipv4: Don't report stale pmtu values to userspace We report cached pmtu values even if they are already expired. Change this to not report these values after they are expired and fix a race in the expire time calculation, as suggested by Eric Dumazet. Signed-off-by: Steffen Klassert Signed-off-by: David S. Miller --- net/ipv4/route.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 741df67a81ec..132e0dfee53a 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2187,8 +2187,18 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway)) goto nla_put_failure; + expires = rt->dst.expires; + if (expires) { + unsigned long now = jiffies; + + if (time_before(now, expires)) + expires -= now; + else + expires = 0; + } + memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics)); - if (rt->rt_pmtu) + if (rt->rt_pmtu && expires) metrics[RTAX_MTU - 1] = rt->rt_pmtu; if (rtnetlink_put_metrics(skb, metrics) < 0) goto nla_put_failure; @@ -2198,13 +2208,6 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, goto nla_put_failure; error = rt->dst.error; - expires = rt->dst.expires; - if (expires) { - if (time_before(jiffies, expires)) - expires -= jiffies; - else - expires = 0; - } if (rt_is_input_route(rt)) { if (nla_put_u32(skb, RTA_IIF, rt->rt_iif)) -- 2.20.1