> -----Original Message----- > From: Paolo Abeni <[email protected]> > Sent: Thursday, November 6, 2025 12:39 PM > To: Chia-Yu Chang (Nokia) <[email protected]>; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; Koen De Schepper (Nokia) > <[email protected]>; [email protected]; > [email protected]; [email protected]; cheshire > <[email protected]>; [email protected]; [email protected]; Vidhi Goel > <[email protected]> > Cc: Olivier Tilmans (Nokia) <[email protected]> > Subject: Re: [PATCH v5 net-next 05/14] tcp: L4S ECT(1) identifier and > NEEDS_ACCECN for CC modules > > > CAUTION: This is an external email. Please be very careful when clicking > links or opening attachments. See the URL nok.it/ext for additional > information. > > > > On 10/30/25 3:34 PM, [email protected] wrote: > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index > > 7f5df7a71f62..d475f80b2248 100644 > > --- a/net/ipv4/tcp_output.c > > +++ b/net/ipv4/tcp_output.c > > @@ -328,12 +328,17 @@ static void tcp_ecn_send(struct sock *sk, struct > > sk_buff *skb, > > struct tcphdr *th, int tcp_header_len) { > > struct tcp_sock *tp = tcp_sk(sk); > > + bool ecn_ect_1; > > > > if (!tcp_ecn_mode_any(tp)) > > return; > > > > + ecn_ect_1 = tp->ecn_flags & TCP_ECN_ECT_1; > > + if (ecn_ect_1 && !tcp_accecn_ace_fail_recv(tp)) > > + __INET_ECN_xmit(sk, true); > > I'm possibly lost, but I can't find ecn_flags TCP_ECN_ECT_1 bit being > set here or elsewhere in this series. > > Also why isn't this chunk under `if (tcp_ecn_mode_accecn(tp))` ? > > /P Hi Paolo,
This bit will be set by congestion control (TCP Prague, which will be submitted after AccECN patch series). It is intended to use ECT-1 rather than ECT-0, and we were thinking this flag can be irrespective to AccECN negotiation. Shall I put in the Prague patch series? Chia-Yu
