text: #ifndef _NETINET_TCP_H
  #define _NETINET_TCP_H
  
  #include <features.h>
  
  #define TCP_NODELAY 1
  #define TCP_MAXSEG	 2
  #define TCP_CORK	 3
  #define TCP_KEEPIDLE	 4
  #define TCP_KEEPINTVL	 5
  #define TCP_KEEPCNT	 6
  #define TCP_SYNCNT	 7
  #define TCP_LINGER2	 8
  #define TCP_DEFER_ACCEPT 9
  #define TCP_WINDOW_CLAMP 10
  #define TCP_INFO	 11
  #define	TCP_QUICKACK	 12
  #define TCP_CONGESTION	 13
  #define TCP_MD5SIG	 14
  #define TCP_THIN_LINEAR_TIMEOUTS 16
  #define TCP_THIN_DUPACK  17
  #define TCP_USER_TIMEOUT 18
  #define TCP_REPAIR       19
  #define TCP_REPAIR_QUEUE 20
  #define TCP_QUEUE_SEQ    21
  #define TCP_REPAIR_OPTIONS 22
  #define TCP_FASTOPEN     23
  #define TCP_TIMESTAMP    24
  #define TCP_NOTSENT_LOWAT 25
  #define TCP_CC_INFO      26
  #define TCP_SAVE_SYN     27
  #define TCP_SAVED_SYN    28
  #define TCP_REPAIR_WINDOW 29
  #define TCP_FASTOPEN_CONNECT 30
  #define TCP_ULP          31
  #define TCP_MD5SIG_EXT   32
  #define TCP_FASTOPEN_KEY 33
  #define TCP_FASTOPEN_NO_COOKIE 34
  #define TCP_ZEROCOPY_RECEIVE   35
  #define TCP_INQ          36
  #define TCP_TX_DELAY     37
  
  #define TCP_CM_INQ TCP_INQ
  
  #define TCP_ESTABLISHED  1
  #define TCP_SYN_SENT     2
  #define TCP_SYN_RECV     3
  #define TCP_FIN_WAIT1    4
  #define TCP_FIN_WAIT2    5
  #define TCP_TIME_WAIT    6
  #define TCP_CLOSE        7
  #define TCP_CLOSE_WAIT   8
  #define TCP_LAST_ACK     9
  #define TCP_LISTEN       10
  #define TCP_CLOSING      11
  
  enum {
  	TCP_NLA_PAD,
  	TCP_NLA_BUSY,
  	TCP_NLA_RWND_LIMITED,
  	TCP_NLA_SNDBUF_LIMITED,
  	TCP_NLA_DATA_SEGS_OUT,
  	TCP_NLA_TOTAL_RETRANS,
  	TCP_NLA_PACING_RATE,
  	TCP_NLA_DELIVERY_RATE,
  	TCP_NLA_SND_CWND,
  	TCP_NLA_REORDERING,
  	TCP_NLA_MIN_RTT,
  	TCP_NLA_RECUR_RETRANS,
  	TCP_NLA_DELIVERY_RATE_APP_LMT,
  	TCP_NLA_SNDQ_SIZE,
  	TCP_NLA_CA_STATE,
  	TCP_NLA_SND_SSTHRESH,
  	TCP_NLA_DELIVERED,
  	TCP_NLA_DELIVERED_CE,
  	TCP_NLA_BYTES_SENT,
  	TCP_NLA_BYTES_RETRANS,
  	TCP_NLA_DSACK_DUPS,
  	TCP_NLA_REORD_SEEN,
  	TCP_NLA_SRTT,
  };
  
  #if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
  #define TCPOPT_EOL              0
  #define TCPOPT_NOP              1
  #define TCPOPT_MAXSEG           2
  #define TCPOPT_WINDOW           3
  #define TCPOPT_SACK_PERMITTED   4
  #define TCPOPT_SACK             5
  #define TCPOPT_TIMESTAMP        8
  #define TCPOLEN_SACK_PERMITTED  2
  #define TCPOLEN_WINDOW          3
  #define TCPOLEN_MAXSEG          4
  #define TCPOLEN_TIMESTAMP       10
  
  #define SOL_TCP 6
  
  #include <sys/types.h>
  #include <sys/socket.h>
  #include <stdint.h>
  
  typedef uint32_t tcp_seq;
  
  #define TH_FIN 0x01
  #define TH_SYN 0x02
  #define TH_RST 0x04
  #define TH_PUSH 0x08
  #define TH_ACK 0x10
  #define TH_URG 0x20
  
  struct tcphdr {
  #ifdef _GNU_SOURCE
  #ifdef __GNUC__
  	__extension__
  #endif
  	union { struct {
  
  	uint16_t source;
  	uint16_t dest;
  	uint32_t seq;
  	uint32_t ack_seq;
  #if __BYTE_ORDER == __LITTLE_ENDIAN
  	uint16_t res1:4;
  	uint16_t doff:4;
  	uint16_t fin:1;
  	uint16_t syn:1;
  	uint16_t rst:1;
  	uint16_t psh:1;
  	uint16_t ack:1;
  	uint16_t urg:1;
  	uint16_t res2:2;
  #else
  	uint16_t doff:4;
  	uint16_t res1:4;
  	uint16_t res2:2;
  	uint16_t urg:1;
  	uint16_t ack:1;
  	uint16_t psh:1;
  	uint16_t rst:1;
  	uint16_t syn:1;
  	uint16_t fin:1;
  #endif
  	uint16_t window;
  	uint16_t check;
  	uint16_t urg_ptr;
  
  	}; struct {
  #endif
  
  	uint16_t th_sport;
  	uint16_t th_dport;
  	uint32_t th_seq;
  	uint32_t th_ack;
  #if __BYTE_ORDER == __LITTLE_ENDIAN
  	uint8_t th_x2:4;
  	uint8_t th_off:4;
  #else
  	uint8_t th_off:4;
  	uint8_t th_x2:4;
  #endif
  	uint8_t th_flags;
  	uint16_t th_win;
  	uint16_t th_sum;
  	uint16_t th_urp;
  
  #ifdef _GNU_SOURCE
  	}; };
  #endif
  };
  #endif
  
  #ifdef _GNU_SOURCE
  #define TCPI_OPT_TIMESTAMPS	1
  #define TCPI_OPT_SACK		2
  #define TCPI_OPT_WSCALE		4
  #define TCPI_OPT_ECN		8
  
  #define TCP_CA_Open		0
  #define TCP_CA_Disorder		1
  #define TCP_CA_CWR		2
  #define TCP_CA_Recovery		3
  #define TCP_CA_Loss		4
  
  struct tcp_info {
  	uint8_t tcpi_state;
  	uint8_t tcpi_ca_state;
  	uint8_t tcpi_retransmits;
  	uint8_t tcpi_probes;
  	uint8_t tcpi_backoff;
  	uint8_t tcpi_options;
  	uint8_t tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
  	uint8_t tcpi_delivery_rate_app_limited : 1;
  	uint32_t tcpi_rto;
  	uint32_t tcpi_ato;
  	uint32_t tcpi_snd_mss;
  	uint32_t tcpi_rcv_mss;
  	uint32_t tcpi_unacked;
  	uint32_t tcpi_sacked;
  	uint32_t tcpi_lost;
  	uint32_t tcpi_retrans;
  	uint32_t tcpi_fackets;
  	uint32_t tcpi_last_data_sent;
  	uint32_t tcpi_last_ack_sent;
  	uint32_t tcpi_last_data_recv;
  	uint32_t tcpi_last_ack_recv;
  	uint32_t tcpi_pmtu;
  	uint32_t tcpi_rcv_ssthresh;
  	uint32_t tcpi_rtt;
  	uint32_t tcpi_rttvar;
  	uint32_t tcpi_snd_ssthresh;
  	uint32_t tcpi_snd_cwnd;
  	uint32_t tcpi_advmss;
  	uint32_t tcpi_reordering;
  	uint32_t tcpi_rcv_rtt;
  	uint32_t tcpi_rcv_space;
  	uint32_t tcpi_total_retrans;
  	uint64_t tcpi_pacing_rate;
  	uint64_t tcpi_max_pacing_rate;
  	uint64_t tcpi_bytes_acked;
  	uint64_t tcpi_bytes_received;
  	uint32_t tcpi_segs_out;
  	uint32_t tcpi_segs_in;
  	uint32_t tcpi_notsent_bytes;
  	uint32_t tcpi_min_rtt;
  	uint32_t tcpi_data_segs_in;
  	uint32_t tcpi_data_segs_out;
  	uint64_t tcpi_delivery_rate;
  	uint64_t tcpi_busy_time;
  	uint64_t tcpi_rwnd_limited;
  	uint64_t tcpi_sndbuf_limited;
  	uint32_t tcpi_delivered;
  	uint32_t tcpi_delivered_ce;
  	uint64_t tcpi_bytes_sent;
  	uint64_t tcpi_bytes_retrans;
  	uint32_t tcpi_dsack_dups;
  	uint32_t tcpi_reord_seen;
  	uint32_t tcpi_rcv_ooopack;
  	uint32_t tcpi_snd_wnd;
  };
  
  #define TCP_MD5SIG_MAXKEYLEN    80
  
  #define TCP_MD5SIG_FLAG_PREFIX  1
  
  struct tcp_md5sig {
  	struct sockaddr_storage tcpm_addr;
  	uint8_t tcpm_flags;
  	uint8_t tcpm_prefixlen;
  	uint16_t tcpm_keylen;
  	uint32_t __tcpm_pad;
  	uint8_t tcpm_key[TCP_MD5SIG_MAXKEYLEN];
  };
  
  struct tcp_diag_md5sig {
  	uint8_t tcpm_family;
  	uint8_t tcpm_prefixlen;
  	uint16_t tcpm_keylen;
  	uint32_t tcpm_addr[4];
  	uint8_t tcpm_key[TCP_MD5SIG_MAXKEYLEN];
  };
  
  #define TCP_REPAIR_ON		1
  #define TCP_REPAIR_OFF		0
  #define TCP_REPAIR_OFF_NO_WP	-1
  
  struct tcp_repair_window {
  	uint32_t snd_wl1;
  	uint32_t snd_wnd;
  	uint32_t max_window;
  	uint32_t rcv_wnd;
  	uint32_t rcv_wup;
  };
  
  struct tcp_zerocopy_receive {
  	uint64_t address;
  	uint32_t length;
  	uint32_t recv_skip_hint;
  };
  
  #endif
  
  #endif
  