1 /* tcp_timer.c 4.7 81/12/12 */ 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 ip = tcb.inp_next; 49 if (ip == 0) { 50 splx(s); 51 return; 52 } 53 for (; ip != &tcb; ip = ip->inp_next) { 54 tp = intotcpcb(ip); 55 for (i = 0; i < TCPT_NTIMERS; i++) { 56 if (tp->t_timer[i] && --tp->t_timer[i] == 0) 57 (void) tcp_usrreq(tp->t_inpcb->inp_socket, 58 PRU_SLOWTIMO, (struct mbuf *)0, 59 (caddr_t)i); 60 } 61 tp->t_idle++; 62 if (tp->t_rtt) 63 tp->t_rtt++; 64 } 65 tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */ 66 splx(s); 67 } 68 69 /* 70 * Cancel all timers for TCP tp. 71 */ 72 tcp_canceltimers(tp) 73 struct tcpcb *tp; 74 { 75 register int i; 76 77 COUNT(TCP_CANCELTIMERS); 78 for (i = 0; i < TCPT_NTIMERS; i++) 79 tp->t_timer[i] = 0; 80 } 81 82 /* 83 * TCP timer processing. 84 */ 85 tcp_timers(tp, timer) 86 register struct tcpcb *tp; 87 int timer; 88 { 89 90 COUNT(TCP_TIMERS); 91 switch (timer) { 92 93 /* 94 * 2 MSL timeout in shutdown went off. Delete connection 95 * control block. 96 */ 97 case TCPT_2MSL: 98 tcp_close(tp); 99 return; 100 101 /* 102 * Retransmission timer went off. Message has not 103 * been acked within retransmit interval. Back off 104 * to a longer retransmit interval and retransmit all 105 * unacknowledged messages in the window. 106 */ 107 case TCPT_REXMT: 108 tp->t_rxtshift++; 109 TCPT_RANGESET(tp->t_timer[TCPT_REXMT], 110 ((int)(2 * tp->t_srtt)) << tp->t_rxtshift, 111 TCPTV_MIN, TCPTV_MAX); 112 tp->snd_nxt = tp->snd_una; 113 /* this only transmits one segment! */ 114 (void) tcp_output(tp); 115 return; 116 117 /* 118 * Persistance timer into zero window. 119 * Force a byte to be output, if possible. 120 */ 121 case TCPT_PERSIST: 122 tp->t_force = 1; 123 (void) tcp_output(tp); 124 tp->t_force = 0; 125 TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], 126 2 * tp->t_srtt, TCPTV_PERSMIN, TCPTV_MAX); 127 return; 128 129 /* 130 * Keep-alive timer went off; send something 131 * or drop connection if idle for too long. 132 */ 133 case TCPT_KEEP: 134 if (tp->t_state < TCPS_ESTABLISHED || 135 tp->t_idle >= TCPTV_MAXIDLE) { 136 tcp_drop(tp, ETIMEDOUT); 137 return; 138 } 139 tcp_respond(tp->t_template, tp->rcv_nxt, tp->snd_una-1, 0); 140 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 141 return; 142 } 143 } 144