On 9/4/17 1:36 AM, Haishuang Yan wrote:
In collect_md mode, if the tun dev is down, it still can call __ip6_tnl_rcv to receive on packets, and the rx statistics increase improperly.Fixes: 8d79266bc48c ("ip6_tunnel: add collect_md mode to IPv6 tunnels") Cc: Alexei Starovoitov <a...@fb.com> Signed-off-by: Haishuang Yan <yanhaishu...@cmss.chinamobile.com> --- Change since v3: * Increment rx_dropped if tunnel device is not up, suggested by Pravin B Shelar * Fix wrong recipient address --- net/ipv6/ip6_tunnel.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 10a693a..e91d3b6 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -171,8 +171,11 @@ static struct net_device_stats *ip6_get_stats(struct net_device *dev) } t = rcu_dereference(ip6n->collect_md_tun); - if (t) - return t; + if (t) { + if (t->dev->flags & IFF_UP) + return t; + t->dev->stats.rx_dropped++; + }
Why increment the stats only for this drop case? There are plenty of other conditions where packet will be dropped in ip6 tunnel. I think it's important to present consistent behavior to the users, so I'd increment drop stats either for all drop cases or for none. And today it's none. The ! IFF_UP case should probably be return NULL too.
