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[34.48.67.23]) by smtp.gmail.com with UTF8SMTPSA id 00721157ae682-717c5d70373sm29865247b3.35.2025.07.16.10.38.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Jul 2025 10:38:04 -0700 (PDT) Date: Wed, 16 Jul 2025 13:38:03 -0400 From: Willem de Bruijn To: Daniel Zahka , Donald Hunter , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Jonathan Corbet , Andrew Lunn Cc: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Boris Pismenny , Kuniyuki Iwashima , Willem de Bruijn , David Ahern , Neal Cardwell , Patrisious Haddad , Raed Salem , Jianbo Liu , Dragos Tatulea , Rahul Rameshbabu , Stanislav Fomichev , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Alexander Lobakin , Jacob Keller , netdev@vger.kernel.org Message-ID: <6877e37bbaf6b_796ff294bf@willemb.c.googlers.com.notmuch> In-Reply-To: <20250716144551.3646755-10-daniel.zahka@gmail.com> References: <20250716144551.3646755-1-daniel.zahka@gmail.com> <20250716144551.3646755-10-daniel.zahka@gmail.com> Subject: Re: [PATCH net-next v4 09/19] net: psp: update the TCP MSS to reflect PSP packet overhead Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Daniel Zahka wrote: > From: Jakub Kicinski > > PSP eats 32B 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. > > Signed-off-by: Jakub Kicinski > Signed-off-by: Daniel Zahka Reviewed-by: Willem de Bruijn