Re: [PATCH net-next v13 09/19] net: psp: update the TCP MSS to reflect PSP packet overhead

On Tue, Sep 16, 2025 at 5:10 PM Daniel Zahka [off-list ref] wrote:

From: Jakub Kicinski <kuba@kernel.org>

PSP eats 40B of header space. Adjust MSS appropriately.

We can either modify tcp_mtu_to_mss() / tcp_mss_to_mtu()
or reuse icsk_ext_hdr_len. The former option is more TCP
specific and has runtime overhead. The latter is a bit
of a hack as PSP is not an ext_hdr. If one squints hard
enough, UDP encap is just a more practical version of
IPv6 exthdr, so go with the latter. Happy to change.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Daniel Zahka <daniel.zahka@gmail.com>

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