Re: [PATCH net-next v4 0/2] tcp: add a new TW_PAWS drop reason

Eric Dumazet
2025-04-09T15:59:02Z

On Wed, Apr 9, 2025 at 1:27 PM Jiayuan Chen <jiayuan.chen@linux.dev> wrote:
>
> Devices in the networking path, such as firewalls, NATs, or routers, which
> can perform SNAT or DNAT, use addresses from their own limited address
> pools to masquerade the source address during forwarding, causing PAWS
> verification to fail more easily under TW status.
>
> Currently, packet loss statistics for PAWS can only be viewed through MIB,
> which is a global metric and cannot be precisely obtained through tracing
> to get the specific 4-tuple of the dropped packet. In the past, we had to
> use kprobe ret to retrieve relevant skb information from
> tcp_timewait_state_process().
>
> We add a drop_reason pointer and a new counter.

Reviewed-by: Eric Dumazet <edumazet@google.com>

Thanks !