Commit f9af2dbb authored by Thomas Higdon's avatar Thomas Higdon Committed by David S. Miller
Browse files

tcp: Add TCP_INFO counter for packets received out-of-order 



For receive-heavy cases on the server-side, we want to track the
connection quality for individual client IPs. This counter, similar to
the existing system-wide TCPOFOQueue counter in /proc/net/netstat,
tracks out-of-order packet reception. By providing this counter in
TCP_INFO, it will allow understanding to what degree receive-heavy
sockets are experiencing out-of-order delivery and packet drops
indicating congestion.

Please note that this is similar to the counter in NetBSD TCP_INFO, and
has the same name.

Also note that we avoid increasing the size of the tcp_sock struct by
taking advantage of a hole.

Signed-off-by: default avatarThomas Higdon <tph@fb.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 40ba6a12

include/linux/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -354,6 +354,8 @@ struct tcp_sock { 
#define BPF_SOCK_OPS_TEST_FLAG(TP, ARG) 0

#endif



	u32 rcv_ooopack; /* Received out-of-order packets, for tcpinfo */



/* Receiver side RTT estimation */

	u32 rcv_rtt_last_tsecr;

	struct {

include/uapi/linux/tcp.h

+2 −0
Original line number Diff line number Diff line
@@ -270,6 +270,8 @@ struct tcp_info { 
	__u64	tcpi_bytes_retrans;  /* RFC4898 tcpEStatsPerfOctetsRetrans */

	__u32	tcpi_dsack_dups;     /* RFC4898 tcpEStatsStackDSACKDups */

	__u32	tcpi_reord_seen;     /* reordering events seen */



	__u32	tcpi_rcv_ooopack;    /* Out-of-order packets received */

};



/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */

net/ipv4/tcp.c

+2 −0
Original line number Diff line number Diff line
@@ -2653,6 +2653,7 @@ int tcp_disconnect(struct sock *sk, int flags) 
	tp->rx_opt.saw_tstamp = 0;

	tp->rx_opt.dsack = 0;

	tp->rx_opt.num_sacks = 0;

	tp->rcv_ooopack = 0;





	/* Clean up fastopen related fields */
@@ -3295,6 +3296,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info) 
	info->tcpi_bytes_retrans = tp->bytes_retrans;

	info->tcpi_dsack_dups = tp->dsack_dups;

	info->tcpi_reord_seen = tp->reord_seen;

	info->tcpi_rcv_ooopack = tp->rcv_ooopack;

	unlock_sock_fast(sk, slow);

}

EXPORT_SYMBOL_GPL(tcp_get_info);

net/ipv4/tcp_input.c

+1 −0
Original line number Diff line number Diff line
@@ -4555,6 +4555,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) 
	tp->pred_flags = 0;

	inet_csk_schedule_ack(sk);



	tp->rcv_ooopack += max_t(u16, 1, skb_shinfo(skb)->gso_segs);

	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFOQUEUE);

	seq = TCP_SKB_CB(skb)->seq;

	end_seq = TCP_SKB_CB(skb)->end_seq;

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