tcp: bpf: Support bpf_getsockopt for TCP_BPF_RTO_MIN

Support bpf_getsockopt if application tries to know what the RTO MIN
of this socket is.

Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250312153523.9860-3-kerneljasonxing@gmail.com

diff --git a/net/core/filter.c b/net/core/filter.c
index 2932de5cc57cedc9490705a382c1211d77e1be78..4d34d35af5c788106250d5974a35288c17461e92 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5295,6 +5295,12 @@ static int bpf_sol_tcp_getsockopt(struct sock *sk, int optname,
                memcpy(optval, &cb_flags, optlen);
                break;
        }
+       case TCP_BPF_RTO_MIN: {
+               int rto_min_us = jiffies_to_usecs(inet_csk(sk)->icsk_rto_min);
+
+               memcpy(optval, &rto_min_us, optlen);
+               break;
+       }
        default:
                return -EINVAL;
        }