From f38805c5d26fe4af97837c10d58074a7496638bf Mon Sep 17 00:00:00 2001 From: Jason Xing Date: Mon, 17 Mar 2025 20:03:13 +0800 Subject: tcp: support TCP_RTO_MIN_US for set/getsockopt use Support adjusting/reading RTO MIN for socket level by using set/getsockopt(). This new option has the same effect as TCP_BPF_RTO_MIN, which means it doesn't affect RTAX_RTO_MIN usage (by using ip route...). Considering that bpf option was implemented before this patch, so we need to use a standalone new option for pure tcp set/getsockopt() use. When the socket is created, its icsk_rto_min is set to the default value that is controlled by sysctl_tcp_rto_min_us. Then if application calls setsockopt() with TCP_RTO_MIN_US flag to pass a valid value, then icsk_rto_min will be overridden in jiffies unit. This patch adds WRITE_ONCE/READ_ONCE to avoid data-race around icsk_rto_min. Signed-off-by: Jason Xing Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250317120314.41404-2-kerneljasonxing@gmail.com Signed-off-by: Jakub Kicinski --- include/uapi/linux/tcp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 92a2e79222ea..a126b3860e63 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -140,6 +140,7 @@ enum { #define TCP_IS_MPTCP 43 /* Is MPTCP being used? */ #define TCP_RTO_MAX_MS 44 /* max rto time in ms */ +#define TCP_RTO_MIN_US 45 /* min rto time in us */ #define TCP_REPAIR_ON 1 #define TCP_REPAIR_OFF 0 -- cgit v1.2.3