diff options
author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-01-15 23:55:09 +0300 |
---|---|---|
committer | Alexei Starovoitov <ast@kernel.org> | 2024-01-24 01:40:23 +0300 |
commit | b18afb6f42292a9154102fed7265ae747bbfbc57 (patch) | |
tree | cdca19b0c57e2ab62989866c8a7eddcab25ea338 /include/net/tcp.h | |
parent | d177c1be06ce28aa8c8710ac55be1b5ad3f314c6 (diff) | |
download | linux-b18afb6f42292a9154102fed7265ae747bbfbc57.tar.xz |
tcp: Move tcp_ns_to_ts() to tcp.h
We will support arbitrary SYN Cookie with BPF.
When BPF prog validates ACK and kfunc allocates a reqsk, we need
to call tcp_ns_to_ts() to calculate an offset of TSval for later
use:
time
t0 : Send SYN+ACK
-> tsval = Initial TSval (Random Number)
t1 : Recv ACK of 3WHS
-> tsoff = TSecr - tcp_ns_to_ts(usec_ts_ok, tcp_clock_ns())
= Initial TSval - t1
t2 : Send ACK
-> tsval = t2 + tsoff
= Initial TSval + (t2 - t1)
= Initial TSval + Time Delta (x)
(x) Note that the time delta does not include the initial RTT
from t0 to t1.
Let's move tcp_ns_to_ts() to tcp.h.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240115205514.68364-2-kuniyu@amazon.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/net/tcp.h')
-rw-r--r-- | include/net/tcp.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index dd78a1181031..114000e71a46 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -577,6 +577,15 @@ static inline u32 tcp_cookie_time(void) return val; } +/* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */ +static inline u64 tcp_ns_to_ts(bool usec_ts, u64 val) +{ + if (usec_ts) + return div_u64(val, NSEC_PER_USEC); + + return div_u64(val, NSEC_PER_MSEC); +} + u32 __cookie_v4_init_sequence(const struct iphdr *iph, const struct tcphdr *th, u16 *mssp); __u32 cookie_v4_init_sequence(const struct sk_buff *skb, __u16 *mss); |