/* F-RTO can only be used if TCP has never retransmitted anything other than
* head (SACK enhanced variant from Appendix B of RFC4138 is more robust here)
*/
+static void tcp_check_reno_reordering(struct sock *sk, const int addend)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ u32 holes;
+
+ holes = max(tp->lost_out, 1U);
+ holes = min(holes, tp->packets_out);
+
+ if ((tp->sacked_out + holes) > tp->packets_out) {
+ tp->sacked_out = tp->packets_out - holes;
+ tcp_update_reordering(sk, tp->packets_out + addend, 0);
+ }
+}
+
+/* Emulate SACKs for SACKless connection: account for a new dupack. */
+
+static void tcp_add_reno_sack(struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ tp->sacked_out++;
+ tcp_check_reno_reordering(sk, 0);
+ tcp_sync_left_out(tp);
+}
+
+/* Account for ACK, ACKing some data in Reno Recovery phase. */
+
+static void tcp_remove_reno_sacks(struct sock *sk, int acked)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (acked > 0) {
+ /* One ACK acked hole. The rest eat duplicate ACKs. */
+ if (acked-1 >= tp->sacked_out)
+ tp->sacked_out = 0;
+ else
+ tp->sacked_out -= acked-1;
+ }
+ tcp_check_reno_reordering(sk, acked);
+ tcp_sync_left_out(tp);
+}
+
+static inline void tcp_reset_reno_sack(struct tcp_sock *tp)
+{
+ tp->sacked_out = 0;
+ tp->left_out = tp->lost_out;
+}
+
int tcp_use_frto(struct sock *sk)
{
const struct tcp_sock *tp = tcp_sk(sk);
return 0;
}
-/* If we receive more dupacks than we expected counting segments
- * in assumption of absent reordering, interpret this as reordering.
- * The only another reason could be bug in receiver TCP.
- */
-static void tcp_check_reno_reordering(struct sock *sk, const int addend)
-{
- struct tcp_sock *tp = tcp_sk(sk);
- u32 holes;
-
- holes = max(tp->lost_out, 1U);
- holes = min(holes, tp->packets_out);
-
- if ((tp->sacked_out + holes) > tp->packets_out) {
- tp->sacked_out = tp->packets_out - holes;
- tcp_update_reordering(sk, tp->packets_out + addend, 0);
- }
-}
-
-/* Emulate SACKs for SACKless connection: account for a new dupack. */
-
-static void tcp_add_reno_sack(struct sock *sk)
-{
- struct tcp_sock *tp = tcp_sk(sk);
- tp->sacked_out++;
- tcp_check_reno_reordering(sk, 0);
- tcp_sync_left_out(tp);
-}
-
-/* Account for ACK, ACKing some data in Reno Recovery phase. */
-
-static void tcp_remove_reno_sacks(struct sock *sk, int acked)
-{
- struct tcp_sock *tp = tcp_sk(sk);
-
- if (acked > 0) {
- /* One ACK acked hole. The rest eat duplicate ACKs. */
- if (acked-1 >= tp->sacked_out)
- tp->sacked_out = 0;
- else
- tp->sacked_out -= acked-1;
- }
- tcp_check_reno_reordering(sk, acked);
- tcp_sync_left_out(tp);
-}
-
-static inline void tcp_reset_reno_sack(struct tcp_sock *tp)
-{
- tp->sacked_out = 0;
- tp->left_out = tp->lost_out;
-}
-
/* RFC: This is from the original, I doubt that this is necessary at all:
* clear xmit_retrans hint if seq of this skb is beyond hint. How could we
* retransmitted past LOST markings in the first place? I'm not fully sure