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| author | Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> | 2009-03-14 14:23:03 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-03-15 20:09:52 -0700 |
| commit | c887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72 (patch) | |
| tree | ee267baadce309166ceea5649292f221cd9a6766 /include | |
| parent | c43d558a5139a3b22dcac3f19f64ecb39130b02e (diff) | |
| download | linux-c887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72.tar.gz linux-c887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72.tar.bz2 linux-c887e6d2d9aee56ee7c9f2af4cec3a5efdcc4c72.zip | |
tcp: consolidate paws check
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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/tcp.h | 18 |
1 files changed, 14 insertions, 4 deletions
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, |