Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2025-01-01 10:45:49 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

tcp: Move tcp_ns_to_ts() to tcp.h

Browse Source 
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>
This commit is contained in:
Kuniyuki Iwashima 2024-01-15 12:55:09 -08:00 committed by Alexei Starovoitov
parent d177c1be06
commit b18afb6f42
2 changed files with 9 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
include/net/tcp.h
View File

@ -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);

9
net/ipv4/syncookies.c
View File

@ -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