From b40671b5ee588c8a61b2d0eacbad32ffc57e9a8f Mon Sep 17 00:00:00 2001 From: Chia-Yu Chang Date: Tue, 16 Sep 2025 10:24:32 +0200 Subject: tcp: accecn: AccECN option failure handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit AccECN option may fail in various way, handle these: - Attempt to negotiate the use of AccECN on the 1st retransmitted SYN - From the 2nd retransmitted SYN, stop AccECN negotiation - Remove option from SYN/ACK rexmits to handle blackholes - If no option arrives in SYN/ACK, assume Option is not usable - If an option arrives later, re-enabled - If option is zeroed, disable AccECN option processing This patch use existing padding bits in tcp_request_sock and holes in tcp_sock without increasing the size. Signed-off-by: Ilpo Järvinen Signed-off-by: Chia-Yu Chang Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250916082434.100722-9-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni --- include/uapi/linux/tcp.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 53e0e85b52be..dce3113787a7 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -323,6 +323,8 @@ struct tcp_info { __u32 tcpi_received_e1_bytes; __u32 tcpi_received_e0_bytes; __u32 tcpi_received_ce_bytes; + __u16 tcpi_accecn_fail_mode; + __u16 tcpi_accecn_opt_seen; }; /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */ -- cgit v1.2.3