A CC that implements tcp_congestion_ops.cong_control() should be able to write app_limited. A built-in CC or one from a kernel module is already able to write to this member of struct tcp_sock. For a BPF program, write access has not been allowed, yet. Signed-off-by: Yixin Shen <bobankhshen@xxxxxxxxx> --- net/ipv4/bpf_tcp_ca.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c index e8b27826283e..ea21c96c03aa 100644 --- a/net/ipv4/bpf_tcp_ca.c +++ b/net/ipv4/bpf_tcp_ca.c @@ -113,6 +113,9 @@ static int bpf_tcp_ca_btf_struct_access(struct bpf_verifier_log *log, case offsetof(struct tcp_sock, ecn_flags): end = offsetofend(struct tcp_sock, ecn_flags); break; + case offsetof(struct tcp_sock, app_limited): + end = offsetofend(struct tcp_sock, app_limited); + break; default: bpf_log(log, "no write support to tcp_sock at off %d\n", off); return -EACCES; -- 2.25.1
