@@ -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);
}
@@ -41,7 +41,6 @@ static siphash_aligned_key_t syncookie_secret[2];
* requested/supported by the syn/synack exchange.
*/
#define TSBITS 6
-#define TSMASK (((__u32)1 << TSBITS) - 1)
static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
u32 count, int c)
@@ -62,27 +61,22 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport,
*/
u64 cookie_init_timestamp(struct request_sock *req, u64 now)
{
- struct inet_request_sock *ireq;
- u32 ts, ts_now = tcp_ns_to_ts(now);
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ u64 ts, ts_now = tcp_ns_to_ts(now);
u32 options = 0;
- ireq = inet_rsk(req);
-
options = ireq->wscale_ok ? ireq->snd_wscale : TS_OPT_WSCALE_MASK;
if (ireq->sack_ok)
options |= TS_OPT_SACK;
if (ireq->ecn_ok)
options |= TS_OPT_ECN;
- ts = ts_now & ~TSMASK;
+ ts = (ts_now >> TSBITS) << TSBITS;
ts |= options;
- if (ts > ts_now) {
- ts >>= TSBITS;
- ts--;
- ts <<= TSBITS;
- ts |= options;
- }
- return (u64)ts * (NSEC_PER_SEC / TCP_TS_HZ);
+ if (ts > ts_now)
+ ts -= (1UL << TSBITS);
+
+ return ts * (NSEC_PER_SEC / TCP_TS_HZ);
}
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> --- include/net/tcp.h | 2 +- net/ipv4/syncookies.c | 20 +++++++------------- 2 files changed, 8 insertions(+), 14 deletions(-)