tcp: fix cookie_init_timestamp() overflows

cookie_init_timestamp() is supposed to return a 64bit timestamp
suitable for both TSval determination and setting of skb->tstamp.

Unfortunately it uses 32bit fields and overflows after
2^32 * 10^6 nsec (~49 days) of uptime.

Generated TSval are still correct, but skb->tstamp might be set
far away in the past, potentially confusing other layers.

tcp_ns_to_ts() is changed to return a full 64bit value,
ts and ts_now variables are changed to u64 type,
and TSMASK is removed in favor of shifts operations.

While we are at it, change this sequence:
		ts >>= TSBITS;
		ts--;
		ts <<= TSBITS;
		ts |= options;
to:
		ts -= (1UL << TSBITS);

Fixes: 9a568de4818d ("tcp: switch TCP TS option (RFC 7323) to 1ms clock")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index bad304d173a5..d47a57a47b50 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -805,7 +805,7 @@ static inline u32 tcp_time_stamp(const struct tcp_sock *tp)
 }
 
 /* Convert a nsec timestamp into TCP TSval timestamp (ms based currently) */
-static inline u32 tcp_ns_to_ts(u64 ns)
+static inline u64 tcp_ns_to_ts(u64 ns)
 {
 	return div_u64(ns, NSEC_PER_SEC / TCP_TS_HZ);
 }