diff options
Diffstat (limited to 'net/ipv4/tcp_output.c')
| -rw-r--r-- | net/ipv4/tcp_output.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index f897c2594954..65b90f73daa0 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -985,9 +985,14 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, } } - /* Simultaneous open SYN/ACK needs AccECN option but not SYN */ + /* Simultaneous open SYN/ACK needs AccECN option but not SYN. + * It is attempted to negotiate the use of AccECN also on the first + * retransmitted SYN, as mentioned in "3.1.4.1. Retransmitted SYNs" + * of AccECN draft. + */ if (unlikely((TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) && tcp_ecn_mode_accecn(tp) && + inet_csk(sk)->icsk_retransmits < 2 && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option) && remaining >= TCPOLEN_ACCECN_BASE)) { opts->use_synack_ecn_bytes = 1; @@ -1076,7 +1081,7 @@ static unsigned int tcp_synack_options(const struct sock *sk, if (treq->accecn_ok && READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option) && - remaining >= TCPOLEN_ACCECN_BASE) { + req->num_timeout < 1 && remaining >= TCPOLEN_ACCECN_BASE) { opts->use_synack_ecn_bytes = 1; remaining -= tcp_options_fit_accecn(opts, 0, remaining); } @@ -1156,7 +1161,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb if (tcp_ecn_mode_accecn(tp)) { int ecn_opt = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_ecn_option); - if (ecn_opt && + if (ecn_opt && tp->saw_accecn_opt && !tcp_accecn_opt_fail_send(tp) && (ecn_opt >= TCP_ACCECN_OPTION_FULL || tp->accecn_opt_demand || tcp_accecn_option_beacon_check(sk))) { opts->use_synack_ecn_bytes = 0; |