tcp: add SRTT to SCM_TIMESTAMPING_OPT_STATS

Add TCP_NLA_SRTT to SCM_TIMESTAMPING_OPT_STATS that reports the smoothed
round trip time in microseconds (tcp_sock.srtt_us >> 3).

Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index e02d31986ff911b0547bd954abcc7339f4668ca6..8bb6cc5f3235696ad264623b19440dd20f1019c7 100644 (file)
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -266,6 +266,7 @@ enum {
        TCP_NLA_BYTES_RETRANS,  /* Data bytes retransmitted */
        TCP_NLA_DSACK_DUPS,     /* DSACK blocks received */
        TCP_NLA_REORD_SEEN,     /* reordering events seen */
+       TCP_NLA_SRTT,           /* smoothed RTT in usecs */
 };
 
 /* for TCP_MD5SIG socket option */

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index ca2b08c0b4a006696e81a5cfc81d3506b7a61569..252048776dbb0727737eb60bde6d606dbf057488 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3242,6 +3242,7 @@ static size_t tcp_opt_stats_get_size(void)
                nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_BYTES_RETRANS */
                nla_total_size(sizeof(u32)) + /* TCP_NLA_DSACK_DUPS */
                nla_total_size(sizeof(u32)) + /* TCP_NLA_REORD_SEEN */
+               nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */
                0;
 }
 
@@ -3295,6 +3296,7 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
                          TCP_NLA_PAD);
        nla_put_u32(stats, TCP_NLA_DSACK_DUPS, tp->dsack_dups);
        nla_put_u32(stats, TCP_NLA_REORD_SEEN, tp->reord_seen);
+       nla_put_u32(stats, TCP_NLA_SRTT, tp->srtt_us >> 3);
 
        return stats;
 }