diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-01-15 12:55:09 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-01-23 14:40:23 -0800 |
| commit | b18afb6f42292a9154102fed7265ae747bbfbc57 (patch) | |
| tree | cdca19b0c57e2ab62989866c8a7eddcab25ea338 | |
| parent | d177c1be06ce28aa8c8710ac55be1b5ad3f314c6 (diff) | |
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>
| -rw-r--r-- | include/net/tcp.h | 9 | ||||
| -rw-r--r-- | net/ipv4/syncookies.c | 9 |
2 files changed, 9 insertions, 9 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); diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 61f1c96cfe63..981944c22820 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -51,15 +51,6 @@ static u32 cookie_hash(__be32 saddr, __be32 daddr, __be16 sport, __be16 dport, count, &syncookie_secret[c]); } -/* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */ -static 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); -} - /* * when syncookies are in effect and tcp timestamps are enabled we encode * tcp options in the lower bits of the timestamp value that will be |