text: /*
   * Copyright (c) 1982, 1986, 1993
   *	The Regents of the University of California.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 4. Neither the name of the University nor the names of its contributors
   *    may be used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
   */
  
  #ifndef _NETINET_TCP_H
  #define _NETINET_TCP_H	1
  
  #include <features.h>
  
  /*
   * User-settable options (used with setsockopt).
   */
  #define	TCP_NODELAY		 1  /* Don't delay send to coalesce packets  */
  #define	TCP_MAXSEG		 2  /* Set maximum segment size  */
  #define TCP_CORK		 3  /* Control sending of partial frames  */
  #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 /* Bock/reenable quick ACKs.  */
  #define TCP_CONGESTION		 13 /* Congestion control algorithm.  */
  #define TCP_MD5SIG		 14 /* TCP MD5 Signature (RFC2385) */
  #define TCP_COOKIE_TRANSACTIONS	 15 /* TCP Cookie Transactions */
  #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 /* Set TCP queue to repair */
  #define TCP_QUEUE_SEQ		 21 /* Set sequence number of repaired queue. */
  #define TCP_REPAIR_OPTIONS	 22 /* Repair TCP connection options */
  #define TCP_FASTOPEN		 23 /* Enable FastOpen on listeners */
  #define TCP_TIMESTAMP		 24 /* TCP time stamp */
  #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.  */
  
  #ifdef __USE_MISC
  # include <sys/types.h>
  # include <sys/socket.h>
  # include <stdint.h>
  
  typedef	uint32_t tcp_seq;
  /*
   * TCP header.
   * Per RFC 793, September, 1981.
   */
  struct tcphdr
    {
      __extension__ union
      {
        struct
        {
  	uint16_t th_sport;	/* source port */
  	uint16_t th_dport;	/* destination port */
  	tcp_seq th_seq;		/* sequence number */
  	tcp_seq th_ack;		/* acknowledgement number */
  # if __BYTE_ORDER == __LITTLE_ENDIAN
  	uint8_t th_x2:4;	/* (unused) */
  	uint8_t th_off:4;	/* data offset */
  # endif
  # if __BYTE_ORDER == __BIG_ENDIAN
  	uint8_t th_off:4;	/* data offset */
  	uint8_t th_x2:4;	/* (unused) */
  # endif
  	uint8_t th_flags;
  # define TH_FIN	0x01
  # define TH_SYN	0x02
  # define TH_RST	0x04
  # define TH_PUSH	0x08
  # define TH_ACK	0x10
  # define TH_URG	0x20
  	uint16_t th_win;	/* window */
  	uint16_t th_sum;	/* checksum */
  	uint16_t th_urp;	/* urgent pointer */
        };
        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;
  # elif __BYTE_ORDER == __BIG_ENDIAN
  	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;
  # else
  #  error "Adjust your <bits/endian.h> defines"
  # endif
  	uint16_t window;
  	uint16_t check;
  	uint16_t urg_ptr;
        };
      };
  };
  
  enum
  {
    TCP_ESTABLISHED = 1,
    TCP_SYN_SENT,
    TCP_SYN_RECV,
    TCP_FIN_WAIT1,
    TCP_FIN_WAIT2,
    TCP_TIME_WAIT,
    TCP_CLOSE,
    TCP_CLOSE_WAIT,
    TCP_LAST_ACK,
    TCP_LISTEN,
    TCP_CLOSING   /* now a valid state */
  };
  
  # define TCPOPT_EOL		0
  # define TCPOPT_NOP		1
  # define TCPOPT_MAXSEG		2
  # define TCPOLEN_MAXSEG		4
  # define TCPOPT_WINDOW		3
  # define TCPOLEN_WINDOW		3
  # define TCPOPT_SACK_PERMITTED	4		/* Experimental */
  # define TCPOLEN_SACK_PERMITTED	2
  # define TCPOPT_SACK		5		/* Experimental */
  # define TCPOPT_TIMESTAMP	8
  # define TCPOLEN_TIMESTAMP	10
  # define TCPOLEN_TSTAMP_APPA	(TCPOLEN_TIMESTAMP+2) /* appendix A */
  
  # define TCPOPT_TSTAMP_HDR	\
      (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
  
  /*
   * Default maximum segment size for TCP.
   * With an IP MSS of 576, this is 536,
   * but 512 is probably more convenient.
   * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
   */
  # define TCP_MSS	512
  
  # define TCP_MAXWIN	65535	/* largest value for (unscaled) window */
  
  # define TCP_MAX_WINSHIFT	14	/* maximum window shift */
  
  # define SOL_TCP		6	/* TCP level */
  
  
  # 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 */
  
  /* Values for tcpi_state.  */
  enum tcp_ca_state
  {
    TCP_CA_Open = 0,
    TCP_CA_Disorder = 1,
    TCP_CA_CWR = 2,
    TCP_CA_Recovery = 3,
    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;
  
    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;
  
    /* Times. */
    uint32_t	tcpi_last_data_sent;
    uint32_t	tcpi_last_ack_sent;	/* Not remembered, sorry.  */
    uint32_t	tcpi_last_data_recv;
    uint32_t	tcpi_last_ack_recv;
  
    /* Metrics. */
    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;
  };
  
  
  /* For TCP_MD5SIG socket option.  */
  #define TCP_MD5SIG_MAXKEYLEN	80
  
  /* tcp_md5sig extension flags for TCP_MD5SIG_EXT.  */
  #define TCP_MD5SIG_FLAG_PREFIX	1 /* Address prefix length.  */
  
  struct tcp_md5sig
  {
    struct sockaddr_storage tcpm_addr;		/* Address associated.  */
    uint8_t	tcpm_flags;			/* Extension flags.  */
    uint8_t	tcpm_prefixlen;			/* Address prefix.  */
    uint16_t	tcpm_keylen;			/* Key length.  */
    uint32_t	__tcpm_pad;			/* Zero.  */
    uint8_t	tcpm_key[TCP_MD5SIG_MAXKEYLEN];	/* Key (binary).  */
  };
  
  /* For socket repair options.  */
  struct tcp_repair_opt
  {
    uint32_t	opt_code;
    uint32_t	opt_val;
  };
  
  /* Queue to repair, for TCP_REPAIR_QUEUE.  */
  enum
  {
    TCP_NO_QUEUE,
    TCP_RECV_QUEUE,
    TCP_SEND_QUEUE,
    TCP_QUEUES_NR,
  };
  
  /* For cookie transactions socket options.  */
  #define TCP_COOKIE_MIN		8		/*  64-bits */
  #define TCP_COOKIE_MAX		16		/* 128-bits */
  #define TCP_COOKIE_PAIR_SIZE	(2*TCP_COOKIE_MAX)
  
  /* Flags for both getsockopt and setsockopt */
  #define TCP_COOKIE_IN_ALWAYS	(1 << 0)	/* Discard SYN without cookie */
  #define TCP_COOKIE_OUT_NEVER	(1 << 1)	/* Prohibit outgoing cookies,
  						 * supercedes everything. */
  
  /* Flags for getsockopt */
  #define TCP_S_DATA_IN		(1 << 2)	/* Was data received? */
  #define TCP_S_DATA_OUT		(1 << 3)	/* Was data sent? */
  
  #define TCP_MSS_DEFAULT		 536U	/* IPv4 (RFC1122, RFC2581) */
  #define TCP_MSS_DESIRED		1220U	/* IPv6 (tunneled), EDNS0 (RFC3226) */
  
  struct tcp_cookie_transactions
  {
    uint16_t	tcpct_flags;
    uint8_t	__tcpct_pad1;
    uint8_t	tcpct_cookie_desired;
    uint16_t	tcpct_s_data_desired;
    uint16_t	tcpct_used;
    uint8_t	tcpct_value[TCP_MSS_DEFAULT];
  };
  
  /* For use with TCP_REPAIR_WINDOW.  */
  struct tcp_repair_window
  {
    uint32_t snd_wl1;
    uint32_t snd_wnd;
    uint32_t max_window;
    uint32_t rcv_wnd;
    uint32_t rcv_wup;
  };
  
  #endif /* Misc.  */
  
  #endif /* netinet/tcp.h */
  