1 /* tcp_timer.c 4.5 81/12/02 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/mbuf.h" 6 #include "../h/socket.h" 7 #include "../h/socketvar.h" 8 #include "../h/protosw.h" 9 #include "../net/in.h" 10 #include "../net/in_pcb.h" 11 #include "../net/in_systm.h" 12 #include "../net/if.h" 13 #include "../net/ip.h" 14 #include "../net/ip_var.h" 15 #include "../net/tcp.h" 16 #include "../net/tcp_fsm.h" 17 #include "../net/tcp_seq.h" 18 #include "../net/tcp_timer.h" 19 #include "../net/tcp_var.h" 20 #include "../net/tcpip.h" 21 #include "../errno.h" 22 23 /* 24 * Fast timeout routine for processing delayed acks 25 */ 26 tcp_fasttimo() 27 { 28 29 COUNT(TCP_FASTTIMO); 30 } 31 32 /* 33 * Tcp protocol timeout routine called every 500 ms. 34 * Updates the timers in all active tcb's and 35 * causes finite state machine actions if timers expire. 36 */ 37 tcp_slowtimo() 38 { 39 register struct inpcb *ip; 40 register struct tcpcb *tp; 41 int s = splnet(); 42 register int i; 43 COUNT(TCP_SLOWTIMO); 44 45 /* 46 * Search through tcb's and update active timers. 47 */ 48 for (ip = tcb.inp_next; ip != &tcb; ip = ip->inp_next) { 49 tp = intotcpcb(ip); 50 for (i = 0; i < TCPT_NTIMERS; i++) { 51 if (tp->t_timer[i] && --tp->t_timer[i] == 0) 52 (void) tcp_usrreq(tp->t_inpcb->inp_socket, 53 PRU_SLOWTIMO, (struct mbuf *)0, 54 (caddr_t)i); 55 } 56 tp->t_idle++; 57 if (tp->t_rtt) 58 tp->t_rtt++; 59 } 60 tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */ 61 splx(s); 62 } 63 64 /* 65 * Cancel all timers for TCP tp. 66 */ 67 tcp_canceltimers(tp) 68 struct tcpcb *tp; 69 { 70 register int i; 71 72 COUNT(TCP_CANCELTIMERS); 73 for (i = 0; i < TCPT_NTIMERS; i++) 74 tp->t_timer[i] = 0; 75 } 76 77 /* 78 * TCP timer processing. 79 */ 80 tcp_timers(tp, timer) 81 register struct tcpcb *tp; 82 int timer; 83 { 84 85 COUNT(TCP_TIMERS); 86 switch (timer) { 87 88 /* 89 * 2 MSL timeout in shutdown went off. Delete connection 90 * control block. 91 */ 92 case TCPT_2MSL: 93 tcp_close(tp); 94 return; 95 96 /* 97 * Retransmission timer went off. Message has not 98 * been acked within retransmit interval. Back off 99 * to a longer retransmit interval and retransmit all 100 * unacknowledged messages in the window. 101 */ 102 case TCPT_REXMT: 103 tp->t_rxtshift++; 104 TCPT_RANGESET(tp->t_timer[TCPT_REXMT], 105 ((int)(2 * tp->t_srtt)) << tp->t_rxtshift, 106 TCPTV_MIN, TCPTV_MAX); 107 tp->snd_nxt = tp->snd_una; 108 /* this only transmits one segment! */ 109 (void) tcp_output(tp); 110 return; 111 112 /* 113 * Persistance timer into zero window. 114 * Force a byte to be output, if possible. 115 */ 116 case TCPT_PERSIST: 117 tp->t_force = 1; 118 (void) tcp_output(tp); 119 tp->t_force = 0; 120 TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], 121 2 * tp->t_srtt, TCPTV_PERSMIN, TCPTV_MAX); 122 return; 123 124 /* 125 * Keep-alive timer went off; send something 126 * or drop connection if idle for too long. 127 */ 128 case TCPT_KEEP: 129 if (tp->t_state < TCPS_ESTABLISHED || 130 tp->t_idle >= TCPTV_MAXIDLE) { 131 tcp_drop(tp, ETIMEDOUT); 132 return; 133 } 134 tcp_respond(tp->t_template, tp->rcv_nxt, tp->snd_una-1, 0); 135 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 136 return; 137 } 138 } 139