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authorYuchung Cheng <ycheng@google.com>2013-01-31 11:16:46 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-02-14 10:48:34 -0800
commit3005cf62aac8c1b68c0201ead876b30a6c0f9ddd (patch)
tree449560481ad3af88b979eacc354d59092f5888d0
parent3cea56174bd3d79f8bb9ec500dfc95c4660a6ca9 (diff)
tcp: detect SYN/data drop when F-RTO is disabled
[ Upstream commit 66555e92fb7a619188c02cceae4bbc414f15f96d ] On receiving the SYN-ACK, Fast Open checks icsk_retransmit for SYN retransmission to detect SYN/data drops. But if F-RTO is disabled, icsk_retransmit is reset at step D of tcp_fastretrans_alert() ( under tcp_ack()) before tcp_rcv_fastopen_synack(). The fix is to use total_retrans instead which accounts for SYN retransmission regardless the use of F-RTO. Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/tcp_input.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 181fc8234a52..765db33e6045 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5639,8 +5639,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
* the remote receives only the retransmitted (regular) SYNs: either
* the original SYN-data or the corresponding SYN-ACK is lost.
*/
- syn_drop = (cookie->len <= 0 && data &&
- inet_csk(sk)->icsk_retransmits);
+ syn_drop = (cookie->len <= 0 && data && tp->total_retrans);
tcp_fastopen_cache_set(sk, mss, cookie, syn_drop);