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-rw-r--r--net/dccp/input.c44
1 files changed, 15 insertions, 29 deletions
diff --git a/net/dccp/input.c b/net/dccp/input.c
index 782cdb7292f..3b651701cfe 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -280,6 +280,7 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
if (dh->dccph_type == DCCP_PKT_RESPONSE) {
const struct inet_connection_sock *icsk = inet_csk(sk);
struct dccp_sock *dp = dccp_sk(sk);
+ long tstamp = dccp_timestamp();
/* Stop the REQUEST timer */
inet_csk_clear_xmit_timer(sk, ICSK_TIME_RETRANS);
@@ -300,11 +301,10 @@ static int dccp_rcv_request_sent_state_process(struct sock *sk,
if (dccp_parse_options(sk, skb))
goto out_invalid_packet;
- /* Obtain RTT sample from SYN exchange (used by CCID 3) */
- if (dp->dccps_options_received.dccpor_timestamp_echo)
- dp->dccps_syn_rtt = dccp_sample_rtt(sk,
- ktime_get_real(),
- NULL);
+ /* Obtain usec RTT sample from SYN exchange (used by CCID 3) */
+ if (likely(dp->dccps_options_received.dccpor_timestamp_echo))
+ dp->dccps_syn_rtt = dccp_sample_rtt(sk, 10 * (tstamp -
+ dp->dccps_options_received.dccpor_timestamp_echo));
if (dccp_msk(sk)->dccpms_send_ack_vector &&
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
@@ -585,36 +585,22 @@ discard:
EXPORT_SYMBOL_GPL(dccp_rcv_state_process);
/**
- * dccp_sample_rtt - Sample RTT from packet exchange
- *
- * @sk: connected dccp_sock
- * @t_recv: receive timestamp of packet with timestamp echo
- * @t_hist: packet history timestamp or NULL
+ * dccp_sample_rtt - Validate and finalise computation of RTT sample
+ * @delta: number of microseconds between packet and acknowledgment
+ * The routine is kept generic to work in different contexts. It should be
+ * called immediately when the ACK used for the RTT sample arrives.
*/
-u32 dccp_sample_rtt(struct sock *sk, ktime_t t_recv, ktime_t *t_hist)
+u32 dccp_sample_rtt(struct sock *sk, long delta)
{
- struct dccp_sock *dp = dccp_sk(sk);
- struct dccp_options_received *or = &dp->dccps_options_received;
- s64 delta;
-
- if (t_hist == NULL) {
- if (!or->dccpor_timestamp_echo) {
- DCCP_WARN("packet without timestamp echo\n");
- return DCCP_SANE_RTT_MAX;
- }
- ktime_sub_us(t_recv, or->dccpor_timestamp_echo * 10);
- delta = ktime_to_us(t_recv);
- } else
- delta = ktime_us_delta(t_recv, *t_hist);
-
- delta -= or->dccpor_elapsed_time * 10; /* either set or 0 */
+ /* dccpor_elapsed_time is either zeroed out or set and > 0 */
+ delta -= dccp_sk(sk)->dccps_options_received.dccpor_elapsed_time * 10;
if (unlikely(delta <= 0)) {
- DCCP_WARN("unusable RTT sample %ld, using min\n", (long)delta);
+ DCCP_WARN("unusable RTT sample %ld, using min\n", delta);
return DCCP_SANE_RTT_MIN;
}
- if (unlikely(delta - (s64)DCCP_SANE_RTT_MAX > 0)) {
- DCCP_WARN("RTT sample %ld too large, using max\n", (long)delta);
+ if (unlikely(delta > DCCP_SANE_RTT_MAX)) {
+ DCCP_WARN("RTT sample %ld too large, using max\n", delta);
return DCCP_SANE_RTT_MAX;
}