On 7/4/25 10:53 AM, chia-yu.chang@xxxxxxxxxxxxxxxxxxx wrote:
> @@ -285,9 +297,33 @@ static inline void tcp_ecn_received_counters(struct sock *sk,
>
> if (len > 0) {
> u8 minlen = tcp_ecnfield_to_accecn_optfield(ecnfield);
> + u32 oldbytes = tp->received_ecn_bytes[ecnfield - 1];
> +
> tp->received_ecn_bytes[ecnfield - 1] += len;
> tp->accecn_minlen = max_t(u8, tp->accecn_minlen,
> minlen);
> +
> + /* Demand AccECN option at least every 2^22 bytes to
> + * avoid overflowing the ECN byte counters.
> + */
> + if ((tp->received_ecn_bytes[ecnfield - 1] ^ oldbytes) &
> + ~((1 << 22) - 1)) {
I don't understand the above statement, I don't think it yield the
result expected according to the above comment.
> @@ -365,6 +401,7 @@ static inline void tcp_accecn_init_counters(struct tcp_sock *tp)
> __tcp_accecn_init_bytes_counters(tp->received_ecn_bytes);
> __tcp_accecn_init_bytes_counters(tp->delivered_ecn_bytes);
> tp->accecn_minlen = 0;
> + tp->accecn_opt_demand = 0;
> tp->est_ecnfield = 0;
> }
>
> @@ -447,6 +484,7 @@ static inline void tcp_ecn_rcv_synack(struct sock *sk, const struct tcphdr *th,
> default:
> tcp_ecn_mode_set(tp, TCP_ECN_MODE_ACCECN);
> tp->syn_ect_rcv = ip_dsfield & INET_ECN_MASK;
> + tp->accecn_opt_demand = 2;
> if (INET_ECN_is_ce(ip_dsfield) &&
> tcp_accecn_validate_syn_feedback(sk, ace,
> tp->syn_ect_snt)) {
> @@ -467,6 +505,7 @@ static inline void tcp_ecn_rcv_syn(struct tcp_sock *tp, const struct tcphdr *th,
> } else {
> tp->syn_ect_rcv = TCP_SKB_CB(skb)->ip_dsfield &
> INET_ECN_MASK;
> + tp->prev_ecnfield = tp->syn_ect_rcv;
> tcp_ecn_mode_set(tp, TCP_ECN_MODE_ACCECN);
> }
> }
> @@ -565,4 +604,16 @@ tcp_ecn_make_synack(const struct request_sock *req, struct tcphdr *th)
> th->ece = 1;
> }
>
> +static inline bool tcp_accecn_option_beacon_check(const struct sock *sk)
> +{
> + const struct tcp_sock *tp = tcp_sk(sk);
> +
> + if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option_beacon))
> + return false;
> +
> + return tcp_stamp_us_delta(tp->tcp_mstamp, tp->accecn_opt_tstamp) *
> + READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option_beacon) >=
> + (tp->srtt_us >> 3);
To be consistent:
u32 ecn_beacon =
READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option_beacon);
if (!ecn_beacon)
return false;
return tcp_stamp_us_delta(tp->tcp_mstamp, tp->accecn_opt_tstamp) *
ecn_beacon // ...
/P
