From 9caad864151e525929d323de96cad382da49c3b2 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 1 Apr 2016 08:52:20 -0700 Subject: tcp: increment sk_drops for listeners Goal: packets dropped by a listener are accounted for. This adds tcp_listendrop() helper, and clears sk_drops in sk_clone_lock() so that children do not inherit their parent drop count. Note that we no longer increment LINUX_MIB_LISTENDROPS counter when sending a SYNCOOKIE, since the SYN packet generated a SYNACK. We already have a separate LINUX_MIB_SYNCOOKIESSENT Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/tcp.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include') diff --git a/include/net/tcp.h b/include/net/tcp.h index a23282996ca9..74d3ed5eb219 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1836,4 +1836,17 @@ static inline void tcp_segs_in(struct tcp_sock *tp, const struct sk_buff *skb) tp->data_segs_in += segs_in; } +/* + * TCP listen path runs lockless. + * We forced "struct sock" to be const qualified to make sure + * we don't modify one of its field by mistake. + * Here, we increment sk_drops which is an atomic_t, so we can safely + * make sock writable again. + */ +static inline void tcp_listendrop(const struct sock *sk) +{ + atomic_inc(&((struct sock *)sk)->sk_drops); + NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS); +} + #endif /* _TCP_H */ -- cgit v1.2.3