tcp: add SYN/data info to TCP_INFO

Add a bit TCPI_OPT_SYN_DATA (32) to the socket option TCP_INFO:tcpi_options.
It's set if the data in SYN (sent or received) is acked by SYN-ACK. Server or
client application can use this information to check Fast Open success rate.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 8a7fc4b..60b7aac 100644 (file)
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -191,7 +191,8 @@ struct tcp_sock {
        u8      do_early_retrans:1,/* Enable RFC5827 early-retransmit  */
                early_retrans_delayed:1, /* Delayed ER timer installed */
                syn_data:1,     /* SYN includes data */
-               syn_fastopen:1; /* SYN includes Fast Open option */
+               syn_fastopen:1, /* SYN includes Fast Open option */
+               syn_data_acked:1;/* data in SYN is acked by SYN-ACK */
 
 /* RTT measurement */
        u32     srtt;           /* smoothed round trip time << 3        */

diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index c4b89a5..e962faa 100644 (file)
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -130,6 +130,7 @@ enum {
 #define TCPI_OPT_WSCALE                4
 #define TCPI_OPT_ECN           8 /* ECN was negociated at TCP session init */
 #define TCPI_OPT_ECN_SEEN      16 /* we received at least one packet with ECT */
+#define TCPI_OPT_SYN_DATA      32 /* SYN-ACK acked data in SYN sent or rcvd */
 
 enum tcp_ca_state {
        TCP_CA_Open = 0,

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index b7c2f43..197c000 100644 (file)
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2764,6 +2764,8 @@ void tcp_get_info(const struct sock *sk, struct tcp_info *info)
                info->tcpi_options |= TCPI_OPT_ECN;
        if (tp->ecn_flags & TCP_ECN_SEEN)
                info->tcpi_options |= TCPI_OPT_ECN_SEEN;
+       if (tp->syn_data_acked)
+               info->tcpi_options |= TCPI_OPT_SYN_DATA;
 
        info->tcpi_rto = jiffies_to_usecs(icsk->icsk_rto);
        info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 432c366..036f857 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5646,6 +5646,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
                tcp_rearm_rto(sk);
                return true;
        }
+       tp->syn_data_acked = tp->syn_data;
        return false;
 }
 

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index ef998b0..0c4a643 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1461,6 +1461,7 @@ static int tcp_v4_conn_req_fastopen(struct sock *sk,
                skb_set_owner_r(skb, child);
                __skb_queue_tail(&child->sk_receive_queue, skb);
                tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+               tp->syn_data_acked = 1;
        }
        sk->sk_data_ready(sk, 0);
        bh_unlock_sock(child);

diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 27536ba..a7302d9 100644 (file)
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -510,6 +510,7 @@ struct sock *tcp_create_openreq_child(struct sock *sk, struct request_sock *req,
                newtp->rx_opt.mss_clamp = req->mss;
                TCP_ECN_openreq_child(newtp, req);
                newtp->fastopen_rsk = NULL;
+               newtp->syn_data_acked = 0;
 
                TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_PASSIVEOPENS);
        }