diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-10-20 12:57:46 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-23 09:35:01 +0100 |
| commit | af7721448a609d1912b57c825194ef6e17fc71a4 (patch) | |
| tree | c202fc0e94d15dcc834e0444c7d53a4cfe4a1f2d /include/net/tcp.h | |
| parent | 3d44de9a10ea2b1658dfaed8ea6d3d7b6e0defbb (diff) | |
| download | linux-af7721448a609d1912b57c825194ef6e17fc71a4.tar.gz | |
tcp: introduce TCP_PAWS_WRAP
tcp_paws_check() uses TCP_PAWS_24DAYS constant to detect if TCP TS
values might have wrapped after a long idle period.
This mechanism is described in RFC 7323 5.5 (Outdated Timestamps)
TCP_PAWS_24DAYS value was based on the assumption of a clock
of 1 Khz.
As we want to adopt a 1 Mhz clock in the future, we reduce
this constant.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/tcp.h')
| -rw-r--r-- | include/net/tcp.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index af72c1dc37f3d..0ab577869d7ac 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -166,7 +166,12 @@ static_assert((1 << ATO_BITS) > TCP_DELACK_MAX); #define MAX_TCP_KEEPCNT 127 #define MAX_TCP_SYNCNT 127 -#define TCP_PAWS_24DAYS (60 * 60 * 24 * 24) +/* Ensure that TCP PAWS checks are relaxed after ~2147 seconds + * to avoid overflows. This assumes a clock smaller than 1 Mhz. + * Default clock is 1 Khz, tcp_usec_ts uses 1 Mhz. + */ +#define TCP_PAWS_WRAP (INT_MAX / USEC_PER_SEC) + #define TCP_PAWS_MSL 60 /* Per-host timestamps are invalidated * after this time. It should be equal * (or greater than) TCP_TIMEWAIT_LEN @@ -1619,7 +1624,7 @@ static inline bool tcp_paws_check(const struct tcp_options_received *rx_opt, if ((s32)(rx_opt->ts_recent - rx_opt->rcv_tsval) <= paws_win) return true; if (unlikely(!time_before32(ktime_get_seconds(), - rx_opt->ts_recent_stamp + TCP_PAWS_24DAYS))) + rx_opt->ts_recent_stamp + TCP_PAWS_WRAP))) return true; /* * Some OSes send SYN and SYNACK messages with tsval=0 tsecr=0, |