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authorYuchung Cheng <ycheng@google.com>2013-03-20 13:32:59 +0000
committerDavid S. Miller <davem@davemloft.net>2013-03-21 11:47:51 -0400
commitab42d9ee3d215ab74a49818ffc53771a88ce7ddf (patch)
treedb72c31294c11da6fcb53581dcb47340bc02f2cb /net/ipv4
parent9b44190dc114c1720b34975b5bfc65aece112ced (diff)
tcp: refactor CA_Loss state processing
Consolidate all of TCP CA_Loss state processing in tcp_fastretrans_alert() into a new function called tcp_process_loss(). This is to prepare the new F-RTO implementation in the next patch. Signed-off-by: Yuchung Cheng <ycheng@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_input.c42
1 files changed, 26 insertions, 16 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 231c79fe91f3..8d821e45b917 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2664,6 +2664,30 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack)
tcp_set_ca_state(sk, TCP_CA_Recovery);
}
+/* Process an ACK in CA_Loss state. Move to CA_Open if lost data are
+ * recovered or spurious. Otherwise retransmits more on partial ACKs.
+ */
+static void tcp_process_loss(struct sock *sk, int flag)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (!before(tp->snd_una, tp->high_seq)) {
+ icsk->icsk_retransmits = 0;
+ tcp_try_undo_recovery(sk);
+ return;
+ }
+
+ if (flag & FLAG_DATA_ACKED)
+ icsk->icsk_retransmits = 0;
+ if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)
+ tcp_reset_reno_sack(tp);
+ if (tcp_try_undo_loss(sk))
+ return;
+ tcp_moderate_cwnd(tp);
+ tcp_xmit_retransmit_queue(sk);
+}
+
/* Process an event, which can update packets-in-flight not trivially.
* Main goal of this function is to calculate new estimate for left_out,
* taking into account both packets sitting in receiver's buffer and
@@ -2710,12 +2734,6 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
tp->retrans_stamp = 0;
} else if (!before(tp->snd_una, tp->high_seq)) {
switch (icsk->icsk_ca_state) {
- case TCP_CA_Loss:
- icsk->icsk_retransmits = 0;
- if (tcp_try_undo_recovery(sk))
- return;
- break;
-
case TCP_CA_CWR:
/* CWR is to be held something *above* high_seq
* is ACKed for CWR bit to reach receiver. */
@@ -2746,18 +2764,10 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked,
newly_acked_sacked = pkts_acked + tp->sacked_out - prior_sacked;
break;
case TCP_CA_Loss:
- if (flag & FLAG_DATA_ACKED)
- icsk->icsk_retransmits = 0;
- if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)
- tcp_reset_reno_sack(tp);
- if (!tcp_try_undo_loss(sk)) {
- tcp_moderate_cwnd(tp);
- tcp_xmit_retransmit_queue(sk);
- return;
- }
+ tcp_process_loss(sk, flag);
if (icsk->icsk_ca_state != TCP_CA_Open)
return;
- /* Loss is undone; fall through to processing in Open state. */
+ /* Fall through to processing in Open state. */
default:
if (tcp_is_reno(tp)) {
if (flag & FLAG_SND_UNA_ADVANCED)