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Diffstat (limited to 'net/ipv4/tcp_input.c')
-rw-r--r--net/ipv4/tcp_input.c97
1 files changed, 34 insertions, 63 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 26c936930e92..cad73b7dfef0 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1392,9 +1392,9 @@ static struct sk_buff *tcp_maybe_skipping_dsack(struct sk_buff *skb,
if (before(next_dup->start_seq, skip_to_seq)) {
skb = tcp_sacktag_skip(skb, sk, next_dup->start_seq, fack_count);
- tcp_sacktag_walk(skb, sk, NULL,
- next_dup->start_seq, next_dup->end_seq,
- 1, fack_count, reord, flag);
+ skb = tcp_sacktag_walk(skb, sk, NULL,
+ next_dup->start_seq, next_dup->end_seq,
+ 1, fack_count, reord, flag);
}
return skb;
@@ -1842,9 +1842,16 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
TCP_SKB_CB(skb)->sacked &= ~TCPCB_SACKED_RETRANS;
}
- /* Don't lost mark skbs that were fwd transmitted after RTO */
- if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED) &&
- !after(TCP_SKB_CB(skb)->end_seq, tp->frto_highmark)) {
+ /* Marking forward transmissions that were made after RTO lost
+ * can cause unnecessary retransmissions in some scenarios,
+ * SACK blocks will mitigate that in some but not in all cases.
+ * We used to not mark them but it was causing break-ups with
+ * receivers that do only in-order receival.
+ *
+ * TODO: we could detect presence of such receiver and select
+ * different behavior per flow.
+ */
+ if (!(TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)) {
TCP_SKB_CB(skb)->sacked |= TCPCB_LOST;
tp->lost_out += tcp_skb_pcount(skb);
}
@@ -1860,7 +1867,7 @@ static void tcp_enter_frto_loss(struct sock *sk, int allowed_segments, int flag)
tp->reordering = min_t(unsigned int, tp->reordering,
sysctl_tcp_reordering);
tcp_set_ca_state(sk, TCP_CA_Loss);
- tp->high_seq = tp->frto_highmark;
+ tp->high_seq = tp->snd_nxt;
TCP_ECN_queue_cwr(tp);
tcp_clear_retrans_hints_partial(tp);
@@ -2476,28 +2483,34 @@ static inline void tcp_complete_cwr(struct sock *sk)
tcp_ca_event(sk, CA_EVENT_COMPLETE_CWR);
}
+static void tcp_try_keep_open(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ int state = TCP_CA_Open;
+
+ if (tcp_left_out(tp) || tp->retrans_out || tp->undo_marker)
+ state = TCP_CA_Disorder;
+
+ if (inet_csk(sk)->icsk_ca_state != state) {
+ tcp_set_ca_state(sk, state);
+ tp->high_seq = tp->snd_nxt;
+ }
+}
+
static void tcp_try_to_open(struct sock *sk, int flag)
{
struct tcp_sock *tp = tcp_sk(sk);
tcp_verify_left_out(tp);
- if (tp->retrans_out == 0)
+ if (!tp->frto_counter && tp->retrans_out == 0)
tp->retrans_stamp = 0;
if (flag & FLAG_ECE)
tcp_enter_cwr(sk, 1);
if (inet_csk(sk)->icsk_ca_state != TCP_CA_CWR) {
- int state = TCP_CA_Open;
-
- if (tcp_left_out(tp) || tp->retrans_out || tp->undo_marker)
- state = TCP_CA_Disorder;
-
- if (inet_csk(sk)->icsk_ca_state != state) {
- tcp_set_ca_state(sk, state);
- tp->high_seq = tp->snd_nxt;
- }
+ tcp_try_keep_open(sk);
tcp_moderate_cwnd(tp);
} else {
tcp_cwnd_down(sk, flag);
@@ -3303,8 +3316,11 @@ no_queue:
return 1;
old_ack:
- if (TCP_SKB_CB(skb)->sacked)
+ if (TCP_SKB_CB(skb)->sacked) {
tcp_sacktag_write_queue(sk, skb, prior_snd_una);
+ if (icsk->icsk_ca_state == TCP_CA_Open)
+ tcp_try_keep_open(sk);
+ }
uninteresting_ack:
SOCK_DEBUG(sk, "Ack %u out of %u:%u\n", ack, tp->snd_una, tp->snd_nxt);
@@ -4525,49 +4541,6 @@ static void tcp_urg(struct sock *sk, struct sk_buff *skb, struct tcphdr *th)
}
}
-static int tcp_defer_accept_check(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- if (tp->defer_tcp_accept.request) {
- int queued_data = tp->rcv_nxt - tp->copied_seq;
- int hasfin = !skb_queue_empty(&sk->sk_receive_queue) ?
- tcp_hdr((struct sk_buff *)
- sk->sk_receive_queue.prev)->fin : 0;
-
- if (queued_data && hasfin)
- queued_data--;
-
- if (queued_data &&
- tp->defer_tcp_accept.listen_sk->sk_state == TCP_LISTEN) {
- if (sock_flag(sk, SOCK_KEEPOPEN)) {
- inet_csk_reset_keepalive_timer(sk,
- keepalive_time_when(tp));
- } else {
- inet_csk_delete_keepalive_timer(sk);
- }
-
- inet_csk_reqsk_queue_add(
- tp->defer_tcp_accept.listen_sk,
- tp->defer_tcp_accept.request,
- sk);
-
- tp->defer_tcp_accept.listen_sk->sk_data_ready(
- tp->defer_tcp_accept.listen_sk, 0);
-
- sock_put(tp->defer_tcp_accept.listen_sk);
- sock_put(sk);
- tp->defer_tcp_accept.listen_sk = NULL;
- tp->defer_tcp_accept.request = NULL;
- } else if (hasfin ||
- tp->defer_tcp_accept.listen_sk->sk_state != TCP_LISTEN) {
- tcp_reset(sk);
- return -1;
- }
- }
- return 0;
-}
-
static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen)
{
struct tcp_sock *tp = tcp_sk(sk);
@@ -4928,8 +4901,6 @@ step5:
tcp_data_snd_check(sk);
tcp_ack_snd_check(sk);
-
- tcp_defer_accept_check(sk);
return 0;
csum_error: