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

     /*-
      * Copyright (c) 1982, 1986, 1993, 1995
      *      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_seq.h   8.3 (Berkeley) 6/21/95
     * $FreeBSD: releng/11.2/sys/netinet/tcp_seq.h 332818 2018-04-20 14:01:08Z jtl $
     */
    
    #ifndef _NETINET_TCP_SEQ_H_
    #define _NETINET_TCP_SEQ_H_
    /*
     * TCP sequence numbers are 32 bit integers operated
     * on with modular arithmetic.  These macros can be
     * used to compare such integers.
     */
    #define SEQ_LT(a,b)     ((int)((a)-(b)) < 0)
    #define SEQ_LEQ(a,b)    ((int)((a)-(b)) <= 0)
    #define SEQ_GT(a,b)     ((int)((a)-(b)) > 0)
    #define SEQ_GEQ(a,b)    ((int)((a)-(b)) >= 0)
    
    #define SEQ_MIN(a, b)   ((SEQ_LT(a, b)) ? (a) : (b))
    #define SEQ_MAX(a, b)   ((SEQ_GT(a, b)) ? (a) : (b))
    
    #define WIN_LT(a,b)     (ntohs(a) < ntohs(b))
    #define WIN_LEQ(a,b)    (ntohs(a) <= ntohs(b))
    #define WIN_GT(a,b)     (ntohs(a) > ntohs(b))
    #define WIN_GEQ(a,b)    (ntohs(a) >= ntohs(b))
    
    #define WIN_MIN(a, b)   ((WIN_LT(a, b)) ? (a) : (b))
    #define WIN_MAX(a, b)   ((WIN_GT(a, b)) ? (a) : (b))
    
    /* for modulo comparisons of timestamps */
    #define TSTMP_LT(a,b)   ((int)((a)-(b)) < 0)
    #define TSTMP_GT(a,b)   ((int)((a)-(b)) > 0)
    #define TSTMP_GEQ(a,b)  ((int)((a)-(b)) >= 0)
    
    /*
     * Macros to initialize tcp sequence numbers for
     * send and receive from initial send and receive
     * sequence numbers.
     */
    #define tcp_rcvseqinit(tp) \
            (tp)->rcv_adv = (tp)->rcv_nxt = (tp)->irs + 1
    
    #define tcp_sendseqinit(tp) \
            (tp)->snd_una = (tp)->snd_nxt = (tp)->snd_max = (tp)->snd_up = \
                (tp)->snd_recover = (tp)->iss
    
    #ifdef _KERNEL
    /*
     * Clock macros for RFC 1323 timestamps.
     */
    #define TCP_TS_TO_TICKS(_t)     ((_t) * hz / 1000)
    
    /* Timestamp wrap-around time, 24 days. */
    #define TCP_PAWS_IDLE   (24 * 24 * 60 * 60 * 1000)
    
    /*
     * tcp_ts_getticks() in ms, should be 1ms < x < 1000ms according to RFC 1323.
     * We always use 1ms granularity independent of hz.
     */
    static __inline u_int
    tcp_ts_getticks(void)
    {
            struct timeval tv;
            u_long ms;
    
            /*
             * getmicrouptime() should be good enough for any 1-1000ms granularity.
             * Do not use getmicrotime() here as it might break nfsroot/tcp.
             */
            getmicrouptime(&tv);
            ms = tv.tv_sec * 1000 + tv.tv_usec / 1000;
    
            return (ms);
   }
   #endif /* _KERNEL */
   
   #endif /* _NETINET_TCP_SEQ_H_ */

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