diff options
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/sysctl_net_ipv4.c | 10 | ||||
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 1 | ||||
| -rw-r--r-- | net/ipv4/tcp_timer.c | 17 |
3 files changed, 24 insertions, 4 deletions
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c index 40fe70fc2015..6ae3345a3bdf 100644 --- a/net/ipv4/sysctl_net_ipv4.c +++ b/net/ipv4/sysctl_net_ipv4.c @@ -34,6 +34,7 @@ static int ip_ttl_min = 1; static int ip_ttl_max = 255; static int tcp_syn_retries_min = 1; static int tcp_syn_retries_max = MAX_TCP_SYNCNT; +static int tcp_syn_linear_timeouts_max = MAX_TCP_SYNCNT; static int ip_ping_group_range_min[] = { 0, 0 }; static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX }; static u32 u32_max_div_HZ = UINT_MAX / HZ; @@ -1470,6 +1471,15 @@ static struct ctl_table ipv4_net_table[] = { .extra1 = SYSCTL_ZERO, .extra2 = &tcp_plb_max_cong_thresh, }, + { + .procname = "tcp_syn_linear_timeouts", + .data = &init_net.ipv4.sysctl_tcp_syn_linear_timeouts, + .maxlen = sizeof(u8), + .mode = 0644, + .proc_handler = proc_dou8vec_minmax, + .extra1 = SYSCTL_ZERO, + .extra2 = &tcp_syn_linear_timeouts_max, + }, { } }; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 39bda2b1066e..db24ed8f8509 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -3275,6 +3275,7 @@ static int __net_init tcp_sk_init(struct net *net) else net->ipv4.tcp_congestion_control = &tcp_reno; + net->ipv4.sysctl_tcp_syn_linear_timeouts = 4; return 0; } diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index b839c2f91292..0d93a2573807 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -234,14 +234,19 @@ static int tcp_write_timeout(struct sock *sk) struct tcp_sock *tp = tcp_sk(sk); struct net *net = sock_net(sk); bool expired = false, do_reset; - int retry_until; + int retry_until, max_retransmits; if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { if (icsk->icsk_retransmits) __dst_negative_advice(sk); retry_until = icsk->icsk_syn_retries ? : READ_ONCE(net->ipv4.sysctl_tcp_syn_retries); - expired = icsk->icsk_retransmits >= retry_until; + + max_retransmits = retry_until; + if (sk->sk_state == TCP_SYN_SENT) + max_retransmits += READ_ONCE(net->ipv4.sysctl_tcp_syn_linear_timeouts); + + expired = icsk->icsk_retransmits >= max_retransmits; } else { if (retransmits_timed_out(sk, READ_ONCE(net->ipv4.sysctl_tcp_retries1), 0)) { /* Black hole detection */ @@ -577,8 +582,12 @@ out_reset_timer: icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { icsk->icsk_backoff = 0; icsk->icsk_rto = min(__tcp_set_rto(tp), TCP_RTO_MAX); - } else { - /* Use normal (exponential) backoff */ + } else if (sk->sk_state != TCP_SYN_SENT || + icsk->icsk_backoff > + READ_ONCE(net->ipv4.sysctl_tcp_syn_linear_timeouts)) { + /* Use normal (exponential) backoff unless linear timeouts are + * activated. + */ icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); } inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |