include/uapi/linux/tcp.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
 /*
  * INET		An implementation of the TCP/IP protocol suite for the LINUX
  *		operating system.  INET is implemented using the  BSD Socket
  *		interface as the means of communication with the user level.
  *
  *		Definitions for the TCP protocol.
  *
  * Version:	@(#)tcp.h	1.0.2	04/28/93
  *
  * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  *
  *		This program is free software; you can redistribute it and/or
  *		modify it under the terms of the GNU General Public License
  *		as published by the Free Software Foundation; either version
  *		2 of the License, or (at your option) any later version.
  */
 #ifndef _UAPI_LINUX_TCP_H
 #define _UAPI_LINUX_TCP_H

 #include <linux/types.h>
 #include <asm/byteorder.h>
 #include <linux/socket.h>

 struct tcphdr {
 	__be16	source;
 	__be16	dest;
 	__be32	seq;
 	__be32	ack_seq;
 #if defined(__LITTLE_ENDIAN_BITFIELD)
 	__u16	res1:4,
 		doff:4,
 		fin:1,
 		syn:1,
 		rst:1,
 		psh:1,
 		ack:1,
 		urg:1,
 		ece:1,
 		cwr:1;
 #elif defined(__BIG_ENDIAN_BITFIELD)
 	__u16	doff:4,
 		res1:4,
 		cwr:1,
 		ece:1,
 		urg:1,
 		ack:1,
 		psh:1,
 		rst:1,
 		syn:1,
 		fin:1;
 #else
 #error	"Adjust your <asm/byteorder.h> defines"
 #endif
 	__be16	window;
 	__sum16	check;
 	__be16	urg_ptr;
 };

 /*
  *	The union cast uses a gcc extension to avoid aliasing problems
  *  (union is compatible to any of its members)
  *  This means this part of the code is -fstrict-aliasing safe now.
  */
 union tcp_word_hdr {
 	struct tcphdr hdr;
 	__be32        words[5];
 };

 #define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])

 enum {
 	TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000),
 	TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000),
 	TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000),
 	TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000),
 	TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000),
 	TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000),
 	TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000),
 	TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000),
 	TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000),
 	TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000)
 };

 /*
  * TCP general constants
  */
 #define TCP_MSS_DEFAULT		 536U	/* IPv4 (RFC1122, RFC2581) */
 #define TCP_MSS_DESIRED		1220U	/* IPv6 (tunneled), EDNS0 (RFC3226) */

 /* TCP socket options */
 #define TCP_NODELAY		1	/* Turn off Nagle's algorithm. */
 #define TCP_MAXSEG		2	/* Limit MSS */
 #define TCP_CORK		3	/* Never send partially complete segments */
 #define TCP_KEEPIDLE		4	/* Start keeplives after this period */
 #define TCP_KEEPINTVL		5	/* Interval between keepalives */
 #define TCP_KEEPCNT		6	/* Number of keepalives before death */
 #define TCP_SYNCNT		7	/* Number of SYN retransmits */
 #define TCP_LINGER2		8	/* Life time of orphaned FIN-WAIT-2 state */
 #define TCP_DEFER_ACCEPT	9	/* Wake up listener only when data arrive */
 #define TCP_WINDOW_CLAMP	10	/* Bound advertised window */
 #define TCP_INFO		11	/* Information about this connection. */
 #define TCP_QUICKACK		12	/* Block/reenable quick acks */
 #define TCP_CONGESTION		13	/* Congestion control algorithm */
 #define TCP_MD5SIG		14	/* TCP MD5 Signature (RFC2385) */
 #define TCP_THIN_LINEAR_TIMEOUTS 16	/* Use linear timeouts for thin streams*/
 #define TCP_THIN_DUPACK		17	/* Fast retrans. after 1 dupack */
 #define TCP_USER_TIMEOUT	18	/* How long for loss retry before timeout */
 #define TCP_REPAIR		19	/* TCP sock is under repair right now */
 #define TCP_REPAIR_QUEUE	20
 #define TCP_QUEUE_SEQ		21
 #define TCP_REPAIR_OPTIONS	22
 #define TCP_FASTOPEN		23	/* Enable FastOpen on listeners */
 #define TCP_TIMESTAMP		24
 #define TCP_NOTSENT_LOWAT	25	/* limit number of unsent bytes in write queue */
 #define TCP_CC_INFO		26	/* Get Congestion Control (optional) info */
 #define TCP_SAVE_SYN		27	/* Record SYN headers for new connections */
 #define TCP_SAVED_SYN		28	/* Get SYN headers recorded for connection */
 #define TCP_REPAIR_WINDOW	29	/* Get/set window parameters */
 #define TCP_FASTOPEN_CONNECT	30	/* Attempt FastOpen with connect */
 #define TCP_ULP			31	/* Attach a ULP to a TCP connection */
 #define TCP_MD5SIG_EXT		32	/* TCP MD5 Signature with extensions */
 #define TCP_FASTOPEN_KEY	33	/* Set the key for Fast Open (cookie) */
 #define TCP_FASTOPEN_NO_COOKIE	34	/* Enable TFO without a TFO cookie */
 #define TCP_ZEROCOPY_RECEIVE	35
 #define TCP_INQ			36	/* Notify bytes available to read as a cmsg on read */

 #define TCP_CM_INQ		TCP_INQ

 #define TCP_TX_DELAY		37	/* delay outgoing packets by XX usec */


 #define TCP_REPAIR_ON		1
 #define TCP_REPAIR_OFF		0
 #define TCP_REPAIR_OFF_NO_WP	-1	/* Turn off without window probes */

 struct tcp_repair_opt {
 	__u32	opt_code;
 	__u32	opt_val;
 };

 struct tcp_repair_window {
 	__u32	snd_wl1;
 	__u32	snd_wnd;
 	__u32	max_window;

 	__u32	rcv_wnd;
 	__u32	rcv_wup;
 };

 enum {
 	TCP_NO_QUEUE,
 	TCP_RECV_QUEUE,
 	TCP_SEND_QUEUE,
 	TCP_QUEUES_NR,
 };

 /* why fastopen failed from client perspective */
 enum tcp_fastopen_client_fail {
 	TFO_STATUS_UNSPEC, /* catch-all */
 	TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
 	TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
 	TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
 };

 /* for TCP_INFO socket option */
 #define TCPI_OPT_TIMESTAMPS	1
 #define TCPI_OPT_SACK		2
 #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 */

 /*
  * Sender's congestion state indicating normal or abnormal situations
  * in the last round of packets sent. The state is driven by the ACK
  * information and timer events.
  */
 enum tcp_ca_state {
 	/*
 	 * Nothing bad has been observed recently.
 	 * No apparent reordering, packet loss, or ECN marks.
 	 */
 	TCP_CA_Open = 0,
 #define TCPF_CA_Open	(1<<TCP_CA_Open)
 	/*
 	 * The sender enters disordered state when it has received DUPACKs or
 	 * SACKs in the last round of packets sent. This could be due to packet
 	 * loss or reordering but needs further information to confirm packets
 	 * have been lost.
 	 */
 	TCP_CA_Disorder = 1,
 #define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
 	/*
 	 * The sender enters Congestion Window Reduction (CWR) state when it
 	 * has received ACKs with ECN-ECE marks, or has experienced congestion
 	 * or packet discard on the sender host (e.g. qdisc).
 	 */
 	TCP_CA_CWR = 2,
 #define TCPF_CA_CWR	(1<<TCP_CA_CWR)
 	/*
 	 * The sender is in fast recovery and retransmitting lost packets,
 	 * typically triggered by ACK events.
 	 */
 	TCP_CA_Recovery = 3,
 #define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
 	/*
 	 * The sender is in loss recovery triggered by retransmission timeout.
 	 */
 	TCP_CA_Loss = 4
 #define TCPF_CA_Loss	(1<<TCP_CA_Loss)
 };

 struct tcp_info {
 	__u8	tcpi_state;
 	__u8	tcpi_ca_state;
 	__u8	tcpi_retransmits;
 	__u8	tcpi_probes;
 	__u8	tcpi_backoff;
 	__u8	tcpi_options;
 	__u8	tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
 	__u8	tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;

 	__u32	tcpi_rto;
 	__u32	tcpi_ato;
 	__u32	tcpi_snd_mss;
 	__u32	tcpi_rcv_mss;

 	__u32	tcpi_unacked;
 	__u32	tcpi_sacked;
 	__u32	tcpi_lost;
 	__u32	tcpi_retrans;
 	__u32	tcpi_fackets;

 	/* Times. */
 	__u32	tcpi_last_data_sent;
 	__u32	tcpi_last_ack_sent;     /* Not remembered, sorry. */
 	__u32	tcpi_last_data_recv;
 	__u32	tcpi_last_ack_recv;

 	/* Metrics. */
 	__u32	tcpi_pmtu;
 	__u32	tcpi_rcv_ssthresh;
 	__u32	tcpi_rtt;
 	__u32	tcpi_rttvar;
 	__u32	tcpi_snd_ssthresh;
 	__u32	tcpi_snd_cwnd;
 	__u32	tcpi_advmss;
 	__u32	tcpi_reordering;

 	__u32	tcpi_rcv_rtt;
 	__u32	tcpi_rcv_space;

 	__u32	tcpi_total_retrans;

 	__u64	tcpi_pacing_rate;
 	__u64	tcpi_max_pacing_rate;
 	__u64	tcpi_bytes_acked;    /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
 	__u64	tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
 	__u32	tcpi_segs_out;	     /* RFC4898 tcpEStatsPerfSegsOut */
 	__u32	tcpi_segs_in;	     /* RFC4898 tcpEStatsPerfSegsIn */

 	__u32	tcpi_notsent_bytes;
 	__u32	tcpi_min_rtt;
 	__u32	tcpi_data_segs_in;	/* RFC4898 tcpEStatsDataSegsIn */
 	__u32	tcpi_data_segs_out;	/* RFC4898 tcpEStatsDataSegsOut */

 	__u64   tcpi_delivery_rate;

 	__u64	tcpi_busy_time;      /* Time (usec) busy sending data */
 	__u64	tcpi_rwnd_limited;   /* Time (usec) limited by receive window */
 	__u64	tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */

 	__u32	tcpi_delivered;
 	__u32	tcpi_delivered_ce;

 	__u64	tcpi_bytes_sent;     /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
 	__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 */

 	__u32	tcpi_snd_wnd;	     /* peer's advertised receive window after
 				      * scaling (bytes)
 				      */
 };

 /* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
 enum {
 	TCP_NLA_PAD,
 	TCP_NLA_BUSY,		/* Time (usec) busy sending data */
 	TCP_NLA_RWND_LIMITED,	/* Time (usec) limited by receive window */
 	TCP_NLA_SNDBUF_LIMITED,	/* Time (usec) limited by send buffer */
 	TCP_NLA_DATA_SEGS_OUT,	/* Data pkts sent including retransmission */
 	TCP_NLA_TOTAL_RETRANS,	/* Data pkts retransmitted */
 	TCP_NLA_PACING_RATE,    /* Pacing rate in bytes per second */
 	TCP_NLA_DELIVERY_RATE,  /* Delivery rate in bytes per second */
 	TCP_NLA_SND_CWND,       /* Sending congestion window */
 	TCP_NLA_REORDERING,     /* Reordering metric */
 	TCP_NLA_MIN_RTT,        /* minimum RTT */
 	TCP_NLA_RECUR_RETRANS,  /* Recurring retransmits for the current pkt */
 	TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
 	TCP_NLA_SNDQ_SIZE,	/* Data (bytes) pending in send queue */
 	TCP_NLA_CA_STATE,	/* ca_state of socket */
 	TCP_NLA_SND_SSTHRESH,	/* Slow start size threshold */
 	TCP_NLA_DELIVERED,	/* Data pkts delivered incl. out-of-order */
 	TCP_NLA_DELIVERED_CE,	/* Like above but only ones w/ CE marks */
 	TCP_NLA_BYTES_SENT,	/* Data bytes sent including retransmission */
 	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 */
 	TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
 	TCP_NLA_BYTES_NOTSENT,	/* Bytes in write queue not yet sent */
 	TCP_NLA_EDT,		/* Earliest departure time (CLOCK_MONOTONIC) */
 	TCP_NLA_TTL,		/* TTL or hop limit of a packet received */
 };

 /* for TCP_MD5SIG socket option */
 #define TCP_MD5SIG_MAXKEYLEN	80

 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
 #define TCP_MD5SIG_FLAG_PREFIX		0x1	/* address prefix length */
 #define TCP_MD5SIG_FLAG_IFINDEX		0x2	/* ifindex set */

 struct tcp_md5sig {
 	struct __kernel_sockaddr_storage tcpm_addr;	/* address associated */
 	__u8	tcpm_flags;				/* extension flags */
 	__u8	tcpm_prefixlen;				/* address prefix */
 	__u16	tcpm_keylen;				/* key length */
 	int	tcpm_ifindex;				/* device index for scope */
 	__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];		/* key (binary) */
 };

 /* INET_DIAG_MD5SIG */
 struct tcp_diag_md5sig {
 	__u8	tcpm_family;
 	__u8	tcpm_prefixlen;
 	__u16	tcpm_keylen;
 	__be32	tcpm_addr[4];
 	__u8	tcpm_key[TCP_MD5SIG_MAXKEYLEN];
 };

 /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */

 #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
 struct tcp_zerocopy_receive {
 	__u64 address;		/* in: address of mapping */
 	__u32 length;		/* in/out: number of bytes to map/mapped */
 	__u32 recv_skip_hint;	/* out: amount of bytes to skip */
 	__u32 inq; /* out: amount of bytes in read queue */
 	__s32 err; /* out: socket error */
 	__u64 copybuf_address;	/* in: copybuf address (small reads) */
 	__s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
 	__u32 flags; /* in: flags */
 	__u64 msg_control; /* ancillary data */
 	__u64 msg_controllen;
 	__u32 msg_flags;
 	__u32 reserved; /* set to 0 for now */
 };
 #endif /* _UAPI_LINUX_TCP_H */
	/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
	/*
	* INET An implementation of the TCP/IP protocol suite for the LINUX
	* operating system. INET is implemented using the BSD Socket
	* interface as the means of communication with the user level.
	*
	* Definitions for the TCP protocol.
	*
	* Version: @(#)tcp.h 1.0.2 04/28/93
	*
	* Author: Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/
	#ifndef _UAPI_LINUX_TCP_H
	#define _UAPI_LINUX_TCP_H

	#include <linux/types.h>
	#include <asm/byteorder.h>
	#include <linux/socket.h>

	struct tcphdr {
	__be16 source;
	__be16 dest;
	__be32 seq;
	__be32 ack_seq;
	#if defined(__LITTLE_ENDIAN_BITFIELD)
	__u16 res1:4,
	doff:4,
	fin:1,
	syn:1,
	rst:1,
	psh:1,
	ack:1,
	urg:1,
	ece:1,
	cwr:1;
	#elif defined(__BIG_ENDIAN_BITFIELD)
	__u16 doff:4,
	res1:4,
	cwr:1,
	ece:1,
	urg:1,
	ack:1,
	psh:1,
	rst:1,
	syn:1,
	fin:1;
	#else
	#error "Adjust your <asm/byteorder.h> defines"
	#endif
	__be16 window;
	__sum16 check;
	__be16 urg_ptr;
	};

	/*
	* The union cast uses a gcc extension to avoid aliasing problems
	* (union is compatible to any of its members)
	* This means this part of the code is -fstrict-aliasing safe now.
	*/
	union tcp_word_hdr {
	struct tcphdr hdr;
	__be32 words[5];
	};

	#define tcp_flag_word(tp) (((union tcp_word_hdr *)(tp))->words[3])

	enum {
	TCP_FLAG_CWR = __constant_cpu_to_be32(0x00800000),
	TCP_FLAG_ECE = __constant_cpu_to_be32(0x00400000),
	TCP_FLAG_URG = __constant_cpu_to_be32(0x00200000),
	TCP_FLAG_ACK = __constant_cpu_to_be32(0x00100000),
	TCP_FLAG_PSH = __constant_cpu_to_be32(0x00080000),
	TCP_FLAG_RST = __constant_cpu_to_be32(0x00040000),
	TCP_FLAG_SYN = __constant_cpu_to_be32(0x00020000),
	TCP_FLAG_FIN = __constant_cpu_to_be32(0x00010000),
	TCP_RESERVED_BITS = __constant_cpu_to_be32(0x0F000000),
	TCP_DATA_OFFSET = __constant_cpu_to_be32(0xF0000000)
	};

	/*
	* TCP general constants
	*/
	#define TCP_MSS_DEFAULT 536U /* IPv4 (RFC1122, RFC2581) */
	#define TCP_MSS_DESIRED 1220U /* IPv6 (tunneled), EDNS0 (RFC3226) */

	/* TCP socket options */
	#define TCP_NODELAY 1 /* Turn off Nagle's algorithm. */
	#define TCP_MAXSEG 2 /* Limit MSS */
	#define TCP_CORK 3 /* Never send partially complete segments */
	#define TCP_KEEPIDLE 4 /* Start keeplives after this period */
	#define TCP_KEEPINTVL 5 /* Interval between keepalives */
	#define TCP_KEEPCNT 6 /* Number of keepalives before death */
	#define TCP_SYNCNT 7 /* Number of SYN retransmits */
	#define TCP_LINGER2 8 /* Life time of orphaned FIN-WAIT-2 state */
	#define TCP_DEFER_ACCEPT 9 /* Wake up listener only when data arrive */
	#define TCP_WINDOW_CLAMP 10 /* Bound advertised window */
	#define TCP_INFO 11 /* Information about this connection. */
	#define TCP_QUICKACK 12 /* Block/reenable quick acks */
	#define TCP_CONGESTION 13 /* Congestion control algorithm */
	#define TCP_MD5SIG 14 /* TCP MD5 Signature (RFC2385) */
	#define TCP_THIN_LINEAR_TIMEOUTS 16 /* Use linear timeouts for thin streams*/
	#define TCP_THIN_DUPACK 17 /* Fast retrans. after 1 dupack */
	#define TCP_USER_TIMEOUT 18 /* How long for loss retry before timeout */
	#define TCP_REPAIR 19 /* TCP sock is under repair right now */
	#define TCP_REPAIR_QUEUE 20
	#define TCP_QUEUE_SEQ 21
	#define TCP_REPAIR_OPTIONS 22
	#define TCP_FASTOPEN 23 /* Enable FastOpen on listeners */
	#define TCP_TIMESTAMP 24
	#define TCP_NOTSENT_LOWAT 25 /* limit number of unsent bytes in write queue */
	#define TCP_CC_INFO 26 /* Get Congestion Control (optional) info */
	#define TCP_SAVE_SYN 27 /* Record SYN headers for new connections */
	#define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */
	#define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */
	#define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */
	#define TCP_ULP 31 /* Attach a ULP to a TCP connection */
	#define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with extensions */
	#define TCP_FASTOPEN_KEY 33 /* Set the key for Fast Open (cookie) */
	#define TCP_FASTOPEN_NO_COOKIE 34 /* Enable TFO without a TFO cookie */
	#define TCP_ZEROCOPY_RECEIVE 35
	#define TCP_INQ 36 /* Notify bytes available to read as a cmsg on read */

	#define TCP_CM_INQ TCP_INQ

	#define TCP_TX_DELAY 37 /* delay outgoing packets by XX usec */


	#define TCP_REPAIR_ON 1
	#define TCP_REPAIR_OFF 0
	#define TCP_REPAIR_OFF_NO_WP -1 /* Turn off without window probes */

	struct tcp_repair_opt {
	__u32 opt_code;
	__u32 opt_val;
	};

	struct tcp_repair_window {
	__u32 snd_wl1;
	__u32 snd_wnd;
	__u32 max_window;

	__u32 rcv_wnd;
	__u32 rcv_wup;
	};

	enum {
	TCP_NO_QUEUE,
	TCP_RECV_QUEUE,
	TCP_SEND_QUEUE,
	TCP_QUEUES_NR,
	};

	/* why fastopen failed from client perspective */
	enum tcp_fastopen_client_fail {
	TFO_STATUS_UNSPEC, /* catch-all */
	TFO_COOKIE_UNAVAILABLE, /* if not in TFO_CLIENT_NO_COOKIE mode */
	TFO_DATA_NOT_ACKED, /* SYN-ACK did not ack SYN data */
	TFO_SYN_RETRANSMITTED, /* SYN-ACK did not ack SYN data after timeout */
	};

	/* for TCP_INFO socket option */
	#define TCPI_OPT_TIMESTAMPS 1
	#define TCPI_OPT_SACK 2
	#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 */

	/*
	* Sender's congestion state indicating normal or abnormal situations
	* in the last round of packets sent. The state is driven by the ACK
	* information and timer events.
	*/
	enum tcp_ca_state {
	/*
	* Nothing bad has been observed recently.
	* No apparent reordering, packet loss, or ECN marks.
	*/
	TCP_CA_Open = 0,
	#define TCPF_CA_Open (1<<TCP_CA_Open)
	/*
	* The sender enters disordered state when it has received DUPACKs or
	* SACKs in the last round of packets sent. This could be due to packet
	* loss or reordering but needs further information to confirm packets
	* have been lost.
	*/
	TCP_CA_Disorder = 1,
	#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
	/*
	* The sender enters Congestion Window Reduction (CWR) state when it
	* has received ACKs with ECN-ECE marks, or has experienced congestion
	* or packet discard on the sender host (e.g. qdisc).
	*/
	TCP_CA_CWR = 2,
	#define TCPF_CA_CWR (1<<TCP_CA_CWR)
	/*
	* The sender is in fast recovery and retransmitting lost packets,
	* typically triggered by ACK events.
	*/
	TCP_CA_Recovery = 3,
	#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
	/*
	* The sender is in loss recovery triggered by retransmission timeout.
	*/
	TCP_CA_Loss = 4
	#define TCPF_CA_Loss (1<<TCP_CA_Loss)
	};

	struct tcp_info {
	__u8 tcpi_state;
	__u8 tcpi_ca_state;
	__u8 tcpi_retransmits;
	__u8 tcpi_probes;
	__u8 tcpi_backoff;
	__u8 tcpi_options;
	__u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
	__u8 tcpi_delivery_rate_app_limited:1, tcpi_fastopen_client_fail:2;

	__u32 tcpi_rto;
	__u32 tcpi_ato;
	__u32 tcpi_snd_mss;
	__u32 tcpi_rcv_mss;

	__u32 tcpi_unacked;
	__u32 tcpi_sacked;
	__u32 tcpi_lost;
	__u32 tcpi_retrans;
	__u32 tcpi_fackets;

	/* Times. */
	__u32 tcpi_last_data_sent;
	__u32 tcpi_last_ack_sent; /* Not remembered, sorry. */
	__u32 tcpi_last_data_recv;
	__u32 tcpi_last_ack_recv;

	/* Metrics. */
	__u32 tcpi_pmtu;
	__u32 tcpi_rcv_ssthresh;
	__u32 tcpi_rtt;
	__u32 tcpi_rttvar;
	__u32 tcpi_snd_ssthresh;
	__u32 tcpi_snd_cwnd;
	__u32 tcpi_advmss;
	__u32 tcpi_reordering;

	__u32 tcpi_rcv_rtt;
	__u32 tcpi_rcv_space;

	__u32 tcpi_total_retrans;

	__u64 tcpi_pacing_rate;
	__u64 tcpi_max_pacing_rate;
	__u64 tcpi_bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked */
	__u64 tcpi_bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived */
	__u32 tcpi_segs_out; /* RFC4898 tcpEStatsPerfSegsOut */
	__u32 tcpi_segs_in; /* RFC4898 tcpEStatsPerfSegsIn */

	__u32 tcpi_notsent_bytes;
	__u32 tcpi_min_rtt;
	__u32 tcpi_data_segs_in; /* RFC4898 tcpEStatsDataSegsIn */
	__u32 tcpi_data_segs_out; /* RFC4898 tcpEStatsDataSegsOut */

	__u64 tcpi_delivery_rate;

	__u64 tcpi_busy_time; /* Time (usec) busy sending data */
	__u64 tcpi_rwnd_limited; /* Time (usec) limited by receive window */
	__u64 tcpi_sndbuf_limited; /* Time (usec) limited by send buffer */

	__u32 tcpi_delivered;
	__u32 tcpi_delivered_ce;

	__u64 tcpi_bytes_sent; /* RFC4898 tcpEStatsPerfHCDataOctetsOut */
	__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 */

	__u32 tcpi_snd_wnd; /* peer's advertised receive window after
	* scaling (bytes)
	*/
	};

	/* netlink attributes types for SCM_TIMESTAMPING_OPT_STATS */
	enum {
	TCP_NLA_PAD,
	TCP_NLA_BUSY, /* Time (usec) busy sending data */
	TCP_NLA_RWND_LIMITED, /* Time (usec) limited by receive window */
	TCP_NLA_SNDBUF_LIMITED, /* Time (usec) limited by send buffer */
	TCP_NLA_DATA_SEGS_OUT, /* Data pkts sent including retransmission */
	TCP_NLA_TOTAL_RETRANS, /* Data pkts retransmitted */
	TCP_NLA_PACING_RATE, /* Pacing rate in bytes per second */
	TCP_NLA_DELIVERY_RATE, /* Delivery rate in bytes per second */
	TCP_NLA_SND_CWND, /* Sending congestion window */
	TCP_NLA_REORDERING, /* Reordering metric */
	TCP_NLA_MIN_RTT, /* minimum RTT */
	TCP_NLA_RECUR_RETRANS, /* Recurring retransmits for the current pkt */
	TCP_NLA_DELIVERY_RATE_APP_LMT, /* delivery rate application limited ? */
	TCP_NLA_SNDQ_SIZE, /* Data (bytes) pending in send queue */
	TCP_NLA_CA_STATE, /* ca_state of socket */
	TCP_NLA_SND_SSTHRESH, /* Slow start size threshold */
	TCP_NLA_DELIVERED, /* Data pkts delivered incl. out-of-order */
	TCP_NLA_DELIVERED_CE, /* Like above but only ones w/ CE marks */
	TCP_NLA_BYTES_SENT, /* Data bytes sent including retransmission */
	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 */
	TCP_NLA_TIMEOUT_REHASH, /* Timeout-triggered rehash attempts */
	TCP_NLA_BYTES_NOTSENT, /* Bytes in write queue not yet sent */
	TCP_NLA_EDT, /* Earliest departure time (CLOCK_MONOTONIC) */
	TCP_NLA_TTL, /* TTL or hop limit of a packet received */
	};

	/* for TCP_MD5SIG socket option */
	#define TCP_MD5SIG_MAXKEYLEN 80

	/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */
	#define TCP_MD5SIG_FLAG_PREFIX 0x1 /* address prefix length */
	#define TCP_MD5SIG_FLAG_IFINDEX 0x2 /* ifindex set */

	struct tcp_md5sig {
	struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
	__u8 tcpm_flags; /* extension flags */
	__u8 tcpm_prefixlen; /* address prefix */
	__u16 tcpm_keylen; /* key length */
	int tcpm_ifindex; /* device index for scope */
	__u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
	};

	/* INET_DIAG_MD5SIG */
	struct tcp_diag_md5sig {
	__u8 tcpm_family;
	__u8 tcpm_prefixlen;
	__u16 tcpm_keylen;
	__be32 tcpm_addr[4];
	__u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN];
	};

	/* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */

	#define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1
	struct tcp_zerocopy_receive {
	__u64 address; /* in: address of mapping */
	__u32 length; /* in/out: number of bytes to map/mapped */
	__u32 recv_skip_hint; /* out: amount of bytes to skip */
	__u32 inq; /* out: amount of bytes in read queue */
	__s32 err; /* out: socket error */
	__u64 copybuf_address; /* in: copybuf address (small reads) */
	__s32 copybuf_len; /* in/out: copybuf bytes avail/used or error */
	__u32 flags; /* in: flags */
	__u64 msg_control; /* ancillary data */
	__u64 msg_controllen;
	__u32 msg_flags;
	__u32 reserved; /* set to 0 for now */
	};
	#endif /* _UAPI_LINUX_TCP_H */