From c887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72 Mon Sep 17 00:00:00 2001 From: Ilpo Järvinen Date: Sat, 14 Mar 2009 14:23:03 +0000 Subject: tcp: consolidate paws check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Wow, it was quite tricky to merge that stream of negations but I think I finally got it right: check & replace_ts_recent: (s32)(rcv_tsval - ts_recent) >= 0 => 0 (s32)(ts_recent - rcv_tsval) <= 0 => 0 discard: (s32)(ts_recent - rcv_tsval) > TCP_PAWS_WINDOW => 1 (s32)(ts_recent - rcv_tsval) <= TCP_PAWS_WINDOW => 0 I toggled the return values of tcp_paws_check around since the old encoding added yet-another negation making tracking of truth-values really complicated. Signed-off-by: Ilpo Järvinen Signed-off-by: David S. Miller --- include/net/tcp.h | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) (limited to 'include/net') diff --git a/include/net/tcp.h b/include/net/tcp.h index d74ac301e6bc..255ca35bea05 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -997,11 +997,21 @@ static inline int tcp_fin_time(const struct sock *sk) return fin_timeout; } -static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, int rst) +static inline int tcp_paws_check(const struct tcp_options_received *rx_opt, + int paws_win) { - if ((s32)(rx_opt->rcv_tsval - rx_opt->ts_recent) >= 0) - return 0; - if (get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS) + if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) + return 1; + if (unlikely(get_seconds() >= rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS)) + return 1; + + return 0; +} + +static inline int tcp_paws_reject(const struct tcp_options_received *rx_opt, + int rst) +{ + if (tcp_paws_check(rx_opt, 0)) return 0; /* RST segments are not recommended to carry timestamp, -- cgit v1.2.3