tcp: early retransmit

[cascardo/linux.git] / include / net / tcp.h

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 0fb84de..685437a 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -252,6 +252,7 @@ extern int sysctl_tcp_max_ssthresh;
 extern int sysctl_tcp_cookie_size;
 extern int sysctl_tcp_thin_linear_timeouts;
 extern int sysctl_tcp_thin_dupack;
+extern int sysctl_tcp_early_retrans;
 
 extern atomic_long_t tcp_memory_allocated;
 extern struct percpu_counter tcp_sockets_allocated;
@@ -797,6 +798,20 @@ static inline void tcp_enable_fack(struct tcp_sock *tp)
        tp->rx_opt.sack_ok |= TCP_FACK_ENABLED;
 }
 
+/* TCP early-retransmit (ER) is similar to but more conservative than
+ * the thin-dupack feature.  Enable ER only if thin-dupack is disabled.
+ */
+static inline void tcp_enable_early_retrans(struct tcp_sock *tp)
+{
+       tp->do_early_retrans = sysctl_tcp_early_retrans &&
+               !sysctl_tcp_thin_dupack && sysctl_tcp_reordering == 3;
+}
+
+static inline void tcp_disable_early_retrans(struct tcp_sock *tp)
+{
+       tp->do_early_retrans = 0;
+}
+
 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
 {
        return tp->sacked_out + tp->lost_out;