[DCCP]: Sample RTT from SYN exchange
Function:
diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index fdd4217..e668cf5 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -481,10 +481,12 @@
* @dccps_hc_rx_insert_options -
* @dccps_hc_tx_insert_options -
* @dccps_xmit_timer - timer for when CCID is not ready to send
+ * @dccps_syn_rtt - RTT sample from Request/Response exchange (in usecs)
*/
struct dccp_sock {
/* inet_connection_sock has to be the first member of dccp_sock */
struct inet_connection_sock dccps_inet_connection;
+#define dccps_syn_rtt dccps_inet_connection.icsk_ack.lrcvtime
__u64 dccps_swl;
__u64 dccps_swh;
__u64 dccps_awl;
diff --git a/net/dccp/input.c b/net/dccp/input.c
index bd578c8..da6ec18 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -300,6 +300,14 @@
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) {
+ struct timeval now;
+
+ dccp_timestamp(sk, &now);
+ dp->dccps_syn_rtt = dccp_sample_rtt(sk, &now, NULL);
+ }
+
if (dccp_msk(sk)->dccpms_send_ack_vector &&
dccp_ackvec_add(dp->dccps_hc_rx_ackvec, sk,
DCCP_SKB_CB(skb)->dccpd_seq,
diff --git a/net/dccp/options.c b/net/dccp/options.c
index 9074ca7..14b6212 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -563,6 +563,14 @@
dccp_insert_options_feat(sk, skb))
return -1;
+ /*
+ * Obtain RTT sample from Request/Response exchange.
+ * This is currently used in CCID 3 initialisation.
+ */
+ if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_REQUEST &&
+ dccp_insert_option_timestamp(sk, skb))
+ return -1;
+
/* XXX: insert other options when appropriate */
if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {