From: Chia-Yu Chang chia-yu.chang@nokia-bell-labs.com
According to Section 3.2.2.1 of AccECN spec (RFC9768), if the Server is in AccECN mode and in SYN-RCVD state, and if it receives a value of zero on a pure ACK with SYN=0 and no SACK blocks, for the rest of the connection the Server MUST NOT set ECT on outgoing packets and MUST NOT respond to AccECN feedback. Nonetheless, as a Data Receiver it MUST NOT disable AccECN feedback.
Signed-off-by: Chia-Yu Chang chia-yu.chang@nokia-bell-labs.com Acked-by: Paolo Abeni pabeni@redhat.com
--- v3: - Remove unnecessary brackets. --- include/net/tcp_ecn.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/net/tcp_ecn.h b/include/net/tcp_ecn.h index 796c613b5ef3..49e0b865fe02 100644 --- a/include/net/tcp_ecn.h +++ b/include/net/tcp_ecn.h @@ -175,7 +175,9 @@ static inline void tcp_accecn_third_ack(struct sock *sk, switch (ace) { case 0x0: /* Invalid value */ - tcp_accecn_fail_mode_set(tp, TCP_ACCECN_ACE_FAIL_RECV); + if (!TCP_SKB_CB(skb)->sacked) + tcp_accecn_fail_mode_set(tp, TCP_ACCECN_ACE_FAIL_RECV | + TCP_ACCECN_OPT_FAIL_RECV); break; case 0x7: case 0x5: