3 files changed, 18 insertions, 0 deletions

diff --git a/include/linux/dccp.h b/include/linux/dccp.h
index fdd4217f1047..e668cf531bab 100644
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -481,10 +481,12 @@ struct dccp_ackvec;
  * @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 bd578c87b2e7..da6ec185ed5b 100644
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -300,6 +300,14 @@ 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) {
+                        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 9074ca7977b2..14b621227323 100644
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -563,6 +563,14 @@ int dccp_insert_options(struct sock *sk, struct sk_buff *skb)
             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) {