/*
 * 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 */

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,
};

/* 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 */

enum tcp_ca_state {
        TCP_CA_Open = 0,
#define TCPF_CA_Open    (1<<TCP_CA_Open)
        TCP_CA_Disorder = 1,
#define TCPF_CA_Disorder (1<<TCP_CA_Disorder)
        TCP_CA_CWR = 2,
#define TCPF_CA_CWR     (1<<TCP_CA_CWR)
        TCP_CA_Recovery = 3,
#define TCPF_CA_Recovery (1<<TCP_CA_Recovery)
        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;

        __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;
};

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

struct tcp_md5sig {
        struct __kernel_sockaddr_storage tcpm_addr;     /* address associated */
        __u16   __tcpm_pad1;                            /* zero */
        __u16   tcpm_keylen;                            /* key length */
        __u32   __tcpm_pad2;                            /* zero */
        __u8    tcpm_key[TCP_MD5SIG_MAXKEYLEN];         /* key (binary) */
};

#endif /* _UAPI_LINUX_TCP_H */