FreeBSD/Linux Kernel Cross Reference
sys/netinet/tcp.h

     /*      $OpenBSD: tcp.h,v 1.23 2022/08/11 09:13:21 claudio Exp $        */
     /*      $NetBSD: tcp.h,v 1.8 1995/04/17 05:32:58 cgd Exp $      */
     
     /*
      * 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.
     * 3. 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_
    
    #include <sys/cdefs.h>
    
    #if __BSD_VISIBLE
    
    typedef u_int32_t tcp_seq;
    
    /*
     * TCP header.
     * Per RFC 793, September, 1981.
     */
    struct tcphdr {
            u_int16_t th_sport;             /* source port */
            u_int16_t th_dport;             /* destination port */
            tcp_seq   th_seq;               /* sequence number */
            tcp_seq   th_ack;               /* acknowledgement number */
    #if _BYTE_ORDER == _LITTLE_ENDIAN
            u_int32_t th_x2:4,              /* (unused) */
                      th_off:4;             /* data offset */
    #endif
    #if _BYTE_ORDER == _BIG_ENDIAN
            u_int32_t th_off:4,             /* data offset */
                      th_x2:4;              /* (unused) */
    #endif
            u_int8_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
    #define TH_ECE    0x40
    #define TH_CWR    0x80
            u_int16_t th_win;                       /* window */
            u_int16_t th_sum;                       /* checksum */
            u_int16_t th_urp;                       /* urgent pointer */
    };
    #define th_reseqlen th_urp                      /* TCP data length for
                                                       resequencing/reassembly */
    
    #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 TCPOLEN_SACK            8               /* 2*sizeof(tcp_seq) */
    #define TCPOPT_TIMESTAMP        8
    #define TCPOLEN_TIMESTAMP               10
    #define TCPOLEN_TSTAMP_APPA             (TCPOLEN_TIMESTAMP+2) /* appendix A */
    #define TCPOPT_SIGNATURE        19
    #define TCPOLEN_SIGNATURE               18
    #define TCPOLEN_SIGLEN          (TCPOLEN_SIGNATURE+2) /* padding */
    
    #define MAX_TCPOPTLEN           40      /* Absolute maximum TCP options len */
    
    #define TCPOPT_TSTAMP_HDR       \
        (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
    
    /* Option definitions */
   #define TCPOPT_SACK_PERMIT_HDR \
   (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
   #define TCPOPT_SACK_HDR   (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
   /* Miscellaneous constants */
   #define MAX_SACK_BLKS   6       /* Max # SACK blocks stored at sender side */
   #define TCP_MAX_SACK    3       /* Max # SACKs sent in any segment */
   #define TCP_SACKHOLE_LIMIT 128  /* Max # SACK holes per connection */
   
   /*
    * 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 */
   
   #endif /* __BSD_VISIBLE */
   
   /*
    * User-settable options (used with setsockopt).
    */
   #define TCP_NODELAY             0x01   /* don't delay send to coalesce pkts */
   #define TCP_MAXSEG              0x02   /* set maximum segment size */
   #define TCP_MD5SIG              0x04   /* enable TCP MD5 signature option */
   #define TCP_SACK_ENABLE         0x08   /* enable SACKs (if disabled by def.) */
   #define TCP_INFO                0x09   /* retrieve tcp_info structure */
   #define TCP_NOPUSH              0x10   /* don't push last block of write */
   
   #define TCPI_OPT_TIMESTAMPS     0x01
   #define TCPI_OPT_SACK           0x02
   #define TCPI_OPT_WSCALE         0x04
   #define TCPI_OPT_ECN            0x08
   #define TCPI_OPT_TOE            0x10
   
   /*
    * The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits
    * the caller to query certain information about the state of a TCP
    * connection.  Provide an overlapping set of fields with the Linux
    * implementation, but at the same time add a lot of OpenBSD specific
    * extra information.
    */
   struct tcp_info {
           uint8_t         tcpi_state;             /* TCP FSM state. */
           uint8_t         __tcpi_ca_state;
           uint8_t         __tcpi_retransmits;
           uint8_t         __tcpi_probes;
           uint8_t         __tcpi_backoff;
           uint8_t         tcpi_options;           /* Options enabled on conn. */
           uint8_t         tcpi_snd_wscale;        /* RFC1323 send shift value. */
           uint8_t         tcpi_rcv_wscale;        /* RFC1323 recv shift value. */
   
           uint32_t        tcpi_rto;          /* Retransmission timeout (usec). */
           uint32_t        __tcpi_ato;
           uint32_t        tcpi_snd_mss;           /* Max segment size for send. */
           uint32_t        tcpi_rcv_mss;           /* Max segment size for recv. */
   
           uint32_t        __tcpi_unacked;
           uint32_t        __tcpi_sacked;
           uint32_t        __tcpi_lost;
           uint32_t        __tcpi_retrans;
           uint32_t        __tcpi_fackets;
   
           /* Times; measurements in usecs. */
           uint32_t        tcpi_last_data_sent;    /* since last sent data. */
           uint32_t        tcpi_last_ack_sent;     /* since last sent ack. */
           uint32_t        tcpi_last_data_recv;    /* since last recv data. */
           uint32_t        tcpi_last_ack_recv;     /* since last recv ack. */
   
           /* Metrics; variable units. */
           uint32_t        __tcpi_pmtu;
           uint32_t        __tcpi_rcv_ssthresh;
           uint32_t        tcpi_rtt;               /* Smoothed RTT in usecs. */
           uint32_t        tcpi_rttvar;            /* RTT variance in usecs. */
           uint32_t        tcpi_snd_ssthresh;      /* Slow start threshold. */
           uint32_t        tcpi_snd_cwnd;          /* Send congestion window. */
           uint32_t        __tcpi_advmss;
           uint32_t        __tcpi_reordering;
   
           uint32_t        __tcpi_rcv_rtt;
           uint32_t        tcpi_rcv_space;         /* Advertised recv window. */
   
           /*
            * Members below this point are only set if process is privileged,
            * otherwise values will be 0.
            */
   
           /* FreeBSD/NetBSD extensions to tcp_info. */
           uint32_t        tcpi_snd_wnd;           /* Advertised send window. */
           uint32_t        tcpi_snd_nxt;           /* Next egress seqno */
           uint32_t        tcpi_rcv_nxt;           /* Next ingress seqno */
           uint32_t        tcpi_toe_tid;           /* HWTID for TOE endpoints */
           uint32_t        tcpi_snd_rexmitpack;    /* Retransmitted packets */
           uint32_t        tcpi_rcv_ooopack;       /* Out-of-order packets */
           uint32_t        tcpi_snd_zerowin;       /* Zero-sized windows sent */
   
           /* OpenBSD extensions */
           uint32_t        tcpi_rttmin;
           uint32_t        tcpi_max_sndwnd;
           uint32_t        tcpi_rcv_adv;
           uint32_t        tcpi_rcv_up;
           uint32_t        tcpi_snd_una;
           uint32_t        tcpi_snd_up;
           uint32_t        tcpi_snd_wl1;
           uint32_t        tcpi_snd_wl2;
           uint32_t        tcpi_snd_max;
           uint32_t        tcpi_ts_recent;
           uint32_t        tcpi_ts_recent_age;
           uint32_t        tcpi_rfbuf_cnt;
           uint32_t        tcpi_rfbuf_ts;
           uint32_t        tcpi_so_rcv_sb_cc;
           uint32_t        tcpi_so_rcv_sb_hiwat;
           uint32_t        tcpi_so_rcv_sb_lowat;
           uint32_t        tcpi_so_rcv_sb_wat;
           uint32_t        tcpi_so_snd_sb_cc;
           uint32_t        tcpi_so_snd_sb_hiwat;
           uint32_t        tcpi_so_snd_sb_lowat;
           uint32_t        tcpi_so_snd_sb_wat;
   };
   
   #endif /* _NETINET_TCP_H_ */

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