1 /* tcp_timer.c 4.15 82/02/25 */ 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 int tcpnodelack = 0; 24 /* 25 * Fast timeout routine for processing delayed acks 26 */ 27 tcp_fasttimo() 28 { 29 register struct inpcb *inp; 30 register struct tcpcb *tp; 31 int s = splnet(); 32 COUNT(TCP_FASTTIMO); 33 34 inp = tcb.inp_next; 35 if (inp) 36 for (; inp != &tcb; inp = inp->inp_next) 37 if ((tp = (struct tcpcb *)inp->inp_ppcb) && 38 (tp->t_flags & TF_DELACK)) { 39 tp->t_flags &= ~TF_DELACK; 40 tp->t_flags |= TF_ACKNOW; 41 (void) tcp_output(tp); 42 } 43 splx(s); 44 } 45 46 /* 47 * Tcp protocol timeout routine called every 500 ms. 48 * Updates the timers in all active tcb's and 49 * causes finite state machine actions if timers expire. 50 */ 51 tcp_slowtimo() 52 { 53 register struct inpcb *ip; 54 register struct tcpcb *tp; 55 int s = splnet(); 56 register int i; 57 COUNT(TCP_SLOWTIMO); 58 59 /* 60 * Search through tcb's and update active timers. 61 */ 62 ip = tcb.inp_next; 63 if (ip == 0) { 64 splx(s); 65 return; 66 } 67 for (; ip != &tcb; ip = ip->inp_next) { 68 tp = intotcpcb(ip); 69 if (tp == 0) 70 continue; 71 for (i = 0; i < TCPT_NTIMERS; i++) { 72 if (tp->t_timer[i] && --tp->t_timer[i] == 0) 73 (void) tcp_usrreq(tp->t_inpcb->inp_socket, 74 PRU_SLOWTIMO, (struct mbuf *)0, 75 (caddr_t)i); 76 } 77 tp->t_idle++; 78 if (tp->t_rtt) 79 tp->t_rtt++; 80 } 81 tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */ 82 splx(s); 83 } 84 85 /* 86 * Cancel all timers for TCP tp. 87 */ 88 tcp_canceltimers(tp) 89 struct tcpcb *tp; 90 { 91 register int i; 92 93 COUNT(TCP_CANCELTIMERS); 94 for (i = 0; i < TCPT_NTIMERS; i++) 95 tp->t_timer[i] = 0; 96 } 97 98 int tcprexmtprint; 99 /* 100 * TCP timer processing. 101 */ 102 tcp_timers(tp, timer) 103 register struct tcpcb *tp; 104 int timer; 105 { 106 107 COUNT(TCP_TIMERS); 108 switch (timer) { 109 110 /* 111 * 2 MSL timeout in shutdown went off. Delete connection 112 * control block. 113 */ 114 case TCPT_2MSL: 115 tcp_close(tp); 116 return; 117 118 /* 119 * Retransmission timer went off. Message has not 120 * been acked within retransmit interval. Back off 121 * to a longer retransmit interval and retransmit all 122 * unacknowledged messages in the window. 123 */ 124 case TCPT_REXMT: 125 tp->t_rxtshift++; 126 if (tp->t_rxtshift > TCP_MAXRXTSHIFT) { 127 tcp_drop(tp, ETIMEDOUT); 128 return; 129 } 130 TCPT_RANGESET(tp->t_timer[TCPT_REXMT], 131 (int)tp->t_srtt, TCPTV_MIN, TCPTV_MAX); 132 TCPT_RANGESET(tp->t_timer[TCPT_REXMT], 133 tp->t_timer[TCPT_REXMT] << tp->t_rxtshift, 134 TCPTV_MIN, TCPTV_MAX); 135 if (tcprexmtprint) 136 printf("rexmt set to %d\n", tp->t_timer[TCPT_REXMT]); 137 tp->snd_nxt = tp->snd_una; 138 /* this only transmits one segment! */ 139 (void) tcp_output(tp); 140 return; 141 142 /* 143 * Persistance timer into zero window. 144 * Force a byte to be output, if possible. 145 */ 146 case TCPT_PERSIST: 147 tp->t_force = 1; 148 (void) tcp_output(tp); 149 tp->t_force = 0; 150 TCPT_RANGESET(tp->t_timer[TCPT_PERSIST], 151 tcp_beta * tp->t_srtt, TCPTV_PERSMIN, TCPTV_MAX); 152 return; 153 154 /* 155 * Keep-alive timer went off; send something 156 * or drop connection if idle for too long. 157 */ 158 case TCPT_KEEP: 159 if (tp->t_state < TCPS_ESTABLISHED || 160 tp->t_idle >= TCPTV_MAXIDLE) { 161 tcp_drop(tp, ETIMEDOUT); 162 return; 163 } 164 if (tp->t_inpcb->inp_socket->so_options & SO_NOKEEPALIVE) 165 tp->t_idle = 0; 166 else 167 tcp_respond(tp, 168 tp->t_template, tp->rcv_nxt, tp->snd_una-1, 0); 169 tp->t_timer[TCPT_KEEP] = TCPTV_KEEP; 170 return; 171 172 #ifdef TCPTRUEOOB 173 /* 174 * Out-of-band data retransmit timer. 175 */ 176 case TCPT_OOBREXMT: 177 if (tp->t_flags & TF_NOOPT) 178 return; 179 (void) tcp_output(tp); 180 TCPT_RANGESET(tp->t_timer[TCPT_OOBREXMT], 181 2 * tp->t_srtt, TCPTV_MIN, TCPTV_MAX); 182 return; 183 #endif 184 } 185 } 186