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Commit 6f73601e authored Oct 19, 2012 by Yuchung Cheng Committed by David S. Miller Oct 22, 2012

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>

parent e6e71054

include/linux/tcp.h

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -191,7 +191,8 @@ struct tcp_sock {
	u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */		u8 do_early_retrans:1,/* Enable RFC5827 early-retransmit */
	early_retrans_delayed:1, /* Delayed ER timer installed */		early_retrans_delayed:1, /* Delayed ER timer installed */
	syn_data:1, /* SYN includes data */		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 */		/* RTT measurement */
	u32 srtt; /* smoothed round trip time << 3 */		u32 srtt; /* smoothed round trip time << 3 */

include/uapi/linux/tcp.h

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -130,6 +130,7 @@ enum {
	#define TCPI_OPT_WSCALE 4		#define TCPI_OPT_WSCALE 4
	#define TCPI_OPT_ECN 8 /* ECN was negociated at TCP session init */		#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_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 {		enum tcp_ca_state {
	TCP_CA_Open = 0,		TCP_CA_Open = 0,

net/ipv4/tcp.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -2764,6 +2764,8 @@ void tcp_get_info(const struct sock sk, struct tcp_info info)
	info->tcpi_options \|= TCPI_OPT_ECN;		info->tcpi_options \|= TCPI_OPT_ECN;
	if (tp->ecn_flags & TCP_ECN_SEEN)		if (tp->ecn_flags & TCP_ECN_SEEN)
	info->tcpi_options \|= TCPI_OPT_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_rto = jiffies_to_usecs(icsk->icsk_rto);
	info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);		info->tcpi_ato = jiffies_to_usecs(icsk->icsk_ack.ato);

net/ipv4/tcp_input.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -5646,6 +5646,7 @@ static bool tcp_rcv_fastopen_synack(struct sock sk, struct sk_buff synack,
	tcp_rearm_rto(sk);		tcp_rearm_rto(sk);
	return true;		return true;
	}		}
			tp->syn_data_acked = tp->syn_data;
	return false;		return false;
	}		}

net/ipv4/tcp_ipv4.c

+1 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1461,6 +1461,7 @@ static int tcp_v4_conn_req_fastopen(struct sock *sk,
	skb_set_owner_r(skb, child);		skb_set_owner_r(skb, child);
	__skb_queue_tail(&child->sk_receive_queue, skb);		__skb_queue_tail(&child->sk_receive_queue, skb);
	tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;		tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
			tp->syn_data_acked = 1;
	}		}
	sk->sk_data_ready(sk, 0);		sk->sk_data_ready(sk, 0);
	bh_unlock_sock(child);		bh_unlock_sock(child);