usr/src/sys/netinet/tcp_timer.h

/*      tcp_timer.h     4.1     81/11/29        */

/*
 * Definitions of the TCP timers.  These timers are counted
 * down PR_SLOWHZ times a second.
 */
#define TCPT_NTIMERS    4

#define TCPT_REXMT      0               /* retransmit */
#define TCPT_2MSL       1               /* 2*msl quiet time timer */
#define TCPT_PERSIST    2               /* retransmit persistance */
#define TCPT_KEEP       3               /* keep alive */

#define TCP_TTL         60              /* time to live for TCP segs */
/*
 * TCPSC constants give various timeouts in ``slow-clock'' ticks.
 */
#define TCPSC_MSL       (120*PR_SLOWHZ)         /* max seg lifetime */
#define TCPSC_REXMT     (  1*PR_SLOWHZ)         /* base retransmit time */
#define TCPSC_KEEP      (240*PR_SLOWHZ)         /* keep alive */
#define TCPSC_PERSIST   (  5*PR_SLOWHZ)         /* retransmit persistance */

#define TCPSC_KEEPTTL   (  4*TCPSC_KEEP)        /* keep alive too long */
#define TCPSC_2MSL      (  2*TCPSC_MSL)         /* 2*msl quiet time timer */

#define TCPSC_TOOLONG   (480*PR_SLOWHZ)

#ifdef  TCPTIMERS
char *tcptimers[] =
    { "INIT", "REXMT", "REXMTTL", "KEEP", "KEEPTTL", "PERSIST", "2MSL" };
#endif