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Diffstat (limited to 'net/ipv4/tcp_recovery.c')
-rw-r--r--net/ipv4/tcp_recovery.c80
1 files changed, 63 insertions, 17 deletions
diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index 3a81720ac0c40..71593e4400abe 100644
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -2,7 +2,7 @@
#include <linux/tcp.h>
#include <net/tcp.h>
-static void tcp_rack_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
+void tcp_mark_skb_lost(struct sock *sk, struct sk_buff *skb)
{
struct tcp_sock *tp = tcp_sk(sk);
@@ -21,6 +21,38 @@ static bool tcp_rack_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)
return t1 > t2 || (t1 == t2 && after(seq1, seq2));
}
+static u32 tcp_rack_reo_wnd(const struct sock *sk)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if (!tp->rack.reord) {
+ /* If reordering has not been observed, be aggressive during
+ * the recovery or starting the recovery by DUPACK threshold.
+ */
+ if (inet_csk(sk)->icsk_ca_state >= TCP_CA_Recovery)
+ return 0;
+
+ if (tp->sacked_out >= tp->reordering &&
+ !(sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_NO_DUPTHRESH))
+ return 0;
+ }
+
+ /* To be more reordering resilient, allow min_rtt/4 settling delay.
+ * Use min_rtt instead of the smoothed RTT because reordering is
+ * often a path property and less related to queuing or delayed ACKs.
+ * Upon receiving DSACKs, linearly increase the window up to the
+ * smoothed RTT.
+ */
+ return min((tcp_min_rtt(tp) >> 2) * tp->rack.reo_wnd_steps,
+ tp->srtt_us >> 3);
+}
+
+s32 tcp_rack_skb_timeout(struct tcp_sock *tp, struct sk_buff *skb, u32 reo_wnd)
+{
+ return tp->rack.rtt_us + reo_wnd -
+ tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);
+}
+
/* RACK loss detection (IETF draft draft-ietf-tcpm-rack-01):
*
* Marks a packet lost, if some packet sent later has been (s)acked.
@@ -44,23 +76,11 @@ static bool tcp_rack_sent_after(u64 t1, u64 t2, u32 seq1, u32 seq2)
static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
{
struct tcp_sock *tp = tcp_sk(sk);
- u32 min_rtt = tcp_min_rtt(tp);
struct sk_buff *skb, *n;
u32 reo_wnd;
*reo_timeout = 0;
- /* To be more reordering resilient, allow min_rtt/4 settling delay
- * (lower-bounded to 1000uS). We use min_rtt instead of the smoothed
- * RTT because reordering is often a path property and less related
- * to queuing or delayed ACKs.
- */
- reo_wnd = 1000;
- if ((tp->rack.reord || inet_csk(sk)->icsk_ca_state < TCP_CA_Recovery) &&
- min_rtt != ~0U) {
- reo_wnd = max((min_rtt >> 2) * tp->rack.reo_wnd_steps, reo_wnd);
- reo_wnd = min(reo_wnd, tp->srtt_us >> 3);
- }
-
+ reo_wnd = tcp_rack_reo_wnd(sk);
list_for_each_entry_safe(skb, n, &tp->tsorted_sent_queue,
tcp_tsorted_anchor) {
struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
@@ -78,10 +98,9 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
/* A packet is lost if it has not been s/acked beyond
* the recent RTT plus the reordering window.
*/
- remaining = tp->rack.rtt_us + reo_wnd -
- tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);
+ remaining = tcp_rack_skb_timeout(tp, skb, reo_wnd);
if (remaining <= 0) {
- tcp_rack_mark_skb_lost(sk, skb);
+ tcp_mark_skb_lost(sk, skb);
list_del_init(&skb->tcp_tsorted_anchor);
} else {
/* Record maximum wait time */
@@ -202,3 +221,30 @@ void tcp_rack_update_reo_wnd(struct sock *sk, struct rate_sample *rs)
tp->rack.reo_wnd_steps = 1;
}
}
+
+/* RFC6582 NewReno recovery for non-SACK connection. It simply retransmits
+ * the next unacked packet upon receiving
+ * a) three or more DUPACKs to start the fast recovery
+ * b) an ACK acknowledging new data during the fast recovery.
+ */
+void tcp_newreno_mark_lost(struct sock *sk, bool snd_una_advanced)
+{
+ const u8 state = inet_csk(sk)->icsk_ca_state;
+ struct tcp_sock *tp = tcp_sk(sk);
+
+ if ((state < TCP_CA_Recovery && tp->sacked_out >= tp->reordering) ||
+ (state == TCP_CA_Recovery && snd_una_advanced)) {
+ struct sk_buff *skb = tcp_rtx_queue_head(sk);
+ u32 mss;
+
+ if (TCP_SKB_CB(skb)->sacked & TCPCB_LOST)
+ return;
+
+ mss = tcp_skb_mss(skb);
+ if (tcp_skb_pcount(skb) > 1 && skb->len > mss)
+ tcp_fragment(sk, TCP_FRAG_IN_RTX_QUEUE, skb,
+ mss, mss, GFP_ATOMIC);
+
+ tcp_skb_mark_lost_uncond_verify(tp, skb);
+ }
+}