/* 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 _LINUX_TCP_H

#define _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<

	/*

	 * 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<

	/*

	 * 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<

	/*

	 * The sender is in fast recovery and retransmitting lost packets,

	 * typically triggered by ACK events.

	 */

	TCP_CA_Recovery = 3,

#define TCPF_CA_Recovery (1<

	/*

	 * The sender is in loss recovery triggered by retransmission timeout.

	 */

	TCP_CA_Loss = 4

#define TCPF_CA_Loss	(1<

};

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) */

};

/* 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, ...) */

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 */

};

#endif /* _LINUX_TCP_H */