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-rw-r--r--net/dccp/ccids/ccid3.c34
-rw-r--r--net/dccp/ccids/lib/packet_history.c40
-rw-r--r--net/dccp/ccids/lib/packet_history.h22
3 files changed, 38 insertions, 58 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c
index eb1bda08eeb..f74e58d9793 100644
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -371,6 +371,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
{
struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
struct ccid3_options_received *opt_recv = &hctx->options_received;
+ struct tfrc_tx_hist_entry *acked;
ktime_t now;
unsigned long t_nfb;
u32 pinv, r_sample;
@@ -384,17 +385,24 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hctx->state != TFRC_SSTATE_NO_FBACK)
return;
- now = ktime_get_real();
-
- /* Estimate RTT from history if ACK number is valid */
- r_sample = tfrc_tx_hist_rtt(hctx->hist,
- DCCP_SKB_CB(skb)->dccpd_ack_seq, now);
- if (r_sample == 0) {
- DCCP_WARN("%s(%p): %s with bogus ACK-%llu\n", dccp_role(sk), sk,
- dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type),
- (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq);
+ /*
+ * Locate the acknowledged packet in the TX history.
+ *
+ * Returning "entry not found" here can for instance happen when
+ * - the host has not sent out anything (e.g. a passive server),
+ * - the Ack is outdated (packet with higher Ack number was received),
+ * - it is a bogus Ack (for a packet not sent on this connection).
+ */
+ acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb));
+ if (acked == NULL)
return;
- }
+ /* For the sake of RTT sampling, ignore/remove all older entries */
+ tfrc_tx_hist_purge(&acked->next);
+
+ /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
+ now = ktime_get_real();
+ r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
+ hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9);
/* Update receive rate in units of 64 * bytes/second */
hctx->x_recv = opt_recv->ccid3or_receive_rate;
@@ -406,11 +414,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
hctx->p = 0;
else /* can not exceed 100% */
hctx->p = scaled_div(1, pinv);
- /*
- * Validate new RTT sample and update moving average
- */
- r_sample = dccp_sample_rtt(sk, r_sample);
- hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9);
+
/*
* Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
*/
diff --git a/net/dccp/ccids/lib/packet_history.c b/net/dccp/ccids/lib/packet_history.c
index 6cc108afdc3..5c445086690 100644
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
@@ -40,18 +40,6 @@
#include "packet_history.h"
#include "../../dccp.h"
-/**
- * tfrc_tx_hist_entry - Simple singly-linked TX history list
- * @next: next oldest entry (LIFO order)
- * @seqno: sequence number of this entry
- * @stamp: send time of packet with sequence number @seqno
- */
-struct tfrc_tx_hist_entry {
- struct tfrc_tx_hist_entry *next;
- u64 seqno;
- ktime_t stamp;
-};
-
/*
* Transmitter History Routines
*/
@@ -73,15 +61,6 @@ void tfrc_tx_packet_history_exit(void)
}
}
-static struct tfrc_tx_hist_entry *
- tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
-{
- while (head != NULL && head->seqno != seqno)
- head = head->next;
-
- return head;
-}
-
int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno)
{
struct tfrc_tx_hist_entry *entry = kmem_cache_alloc(tfrc_tx_hist_slab, gfp_any());
@@ -111,25 +90,6 @@ void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp)
}
EXPORT_SYMBOL_GPL(tfrc_tx_hist_purge);
-u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
- const ktime_t now)
-{
- u32 rtt = 0;
- struct tfrc_tx_hist_entry *packet = tfrc_tx_hist_find_entry(head, seqno);
-
- if (packet != NULL) {
- rtt = ktime_us_delta(now, packet->stamp);
- /*
- * Garbage-collect older (irrelevant) entries:
- */
- tfrc_tx_hist_purge(&packet->next);
- }
-
- return rtt;
-}
-EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
-
-
/*
* Receiver History Routines
*/
diff --git a/net/dccp/ccids/lib/packet_history.h b/net/dccp/ccids/lib/packet_history.h
index 461cc91cce8..221d8102da5 100644
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -40,12 +40,28 @@
#include <linux/slab.h>
#include "tfrc.h"
-struct tfrc_tx_hist_entry;
+/**
+ * tfrc_tx_hist_entry - Simple singly-linked TX history list
+ * @next: next oldest entry (LIFO order)
+ * @seqno: sequence number of this entry
+ * @stamp: send time of packet with sequence number @seqno
+ */
+struct tfrc_tx_hist_entry {
+ struct tfrc_tx_hist_entry *next;
+ u64 seqno;
+ ktime_t stamp;
+};
+
+static inline struct tfrc_tx_hist_entry *
+ tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno)
+{
+ while (head != NULL && head->seqno != seqno)
+ head = head->next;
+ return head;
+}
extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno);
extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
-extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
- const u64 seqno, const ktime_t now);
/* Subtraction a-b modulo-16, respects circular wrap-around */
#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)