1 /* 2 * LAPB release 002 3 * 4 * This code REQUIRES 2.1.15 or higher/ NET3.038 5 * 6 * This module: 7 * This module is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * History 13 * LAPB 001 Jonathan Naylor Started Coding 14 * LAPB 002 Jonathan Naylor New timer architecture. 15 */ 16 17 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 18 19 #include <linux/errno.h> 20 #include <linux/types.h> 21 #include <linux/socket.h> 22 #include <linux/in.h> 23 #include <linux/kernel.h> 24 #include <linux/jiffies.h> 25 #include <linux/timer.h> 26 #include <linux/string.h> 27 #include <linux/sockios.h> 28 #include <linux/net.h> 29 #include <linux/inet.h> 30 #include <linux/skbuff.h> 31 #include <net/sock.h> 32 #include <linux/uaccess.h> 33 #include <linux/fcntl.h> 34 #include <linux/mm.h> 35 #include <linux/interrupt.h> 36 #include <net/lapb.h> 37 38 static void lapb_t1timer_expiry(struct timer_list *); 39 static void lapb_t2timer_expiry(struct timer_list *); 40 41 void lapb_start_t1timer(struct lapb_cb *lapb) 42 { 43 del_timer(&lapb->t1timer); 44 45 lapb->t1timer.function = lapb_t1timer_expiry; 46 lapb->t1timer.expires = jiffies + lapb->t1; 47 48 add_timer(&lapb->t1timer); 49 } 50 51 void lapb_start_t2timer(struct lapb_cb *lapb) 52 { 53 del_timer(&lapb->t2timer); 54 55 lapb->t2timer.function = lapb_t2timer_expiry; 56 lapb->t2timer.expires = jiffies + lapb->t2; 57 58 add_timer(&lapb->t2timer); 59 } 60 61 void lapb_stop_t1timer(struct lapb_cb *lapb) 62 { 63 del_timer(&lapb->t1timer); 64 } 65 66 void lapb_stop_t2timer(struct lapb_cb *lapb) 67 { 68 del_timer(&lapb->t2timer); 69 } 70 71 int lapb_t1timer_running(struct lapb_cb *lapb) 72 { 73 return timer_pending(&lapb->t1timer); 74 } 75 76 static void lapb_t2timer_expiry(struct timer_list *t) 77 { 78 struct lapb_cb *lapb = from_timer(lapb, t, t2timer); 79 80 if (lapb->condition & LAPB_ACK_PENDING_CONDITION) { 81 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 82 lapb_timeout_response(lapb); 83 } 84 } 85 86 static void lapb_t1timer_expiry(struct timer_list *t) 87 { 88 struct lapb_cb *lapb = from_timer(lapb, t, t1timer); 89 90 switch (lapb->state) { 91 92 /* 93 * If we are a DCE, keep going DM .. DM .. DM 94 */ 95 case LAPB_STATE_0: 96 if (lapb->mode & LAPB_DCE) 97 lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE); 98 break; 99 100 /* 101 * Awaiting connection state, send SABM(E), up to N2 times. 102 */ 103 case LAPB_STATE_1: 104 if (lapb->n2count == lapb->n2) { 105 lapb_clear_queues(lapb); 106 lapb->state = LAPB_STATE_0; 107 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 108 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); 109 return; 110 } else { 111 lapb->n2count++; 112 if (lapb->mode & LAPB_EXTENDED) { 113 lapb_dbg(1, "(%p) S1 TX SABME(1)\n", 114 lapb->dev); 115 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); 116 } else { 117 lapb_dbg(1, "(%p) S1 TX SABM(1)\n", 118 lapb->dev); 119 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); 120 } 121 } 122 break; 123 124 /* 125 * Awaiting disconnection state, send DISC, up to N2 times. 126 */ 127 case LAPB_STATE_2: 128 if (lapb->n2count == lapb->n2) { 129 lapb_clear_queues(lapb); 130 lapb->state = LAPB_STATE_0; 131 lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT); 132 lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); 133 return; 134 } else { 135 lapb->n2count++; 136 lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev); 137 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 138 } 139 break; 140 141 /* 142 * Data transfer state, restransmit I frames, up to N2 times. 143 */ 144 case LAPB_STATE_3: 145 if (lapb->n2count == lapb->n2) { 146 lapb_clear_queues(lapb); 147 lapb->state = LAPB_STATE_0; 148 lapb_stop_t2timer(lapb); 149 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 150 lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); 151 return; 152 } else { 153 lapb->n2count++; 154 lapb_requeue_frames(lapb); 155 lapb_kick(lapb); 156 } 157 break; 158 159 /* 160 * Frame reject state, restransmit FRMR frames, up to N2 times. 161 */ 162 case LAPB_STATE_4: 163 if (lapb->n2count == lapb->n2) { 164 lapb_clear_queues(lapb); 165 lapb->state = LAPB_STATE_0; 166 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 167 lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev); 168 return; 169 } else { 170 lapb->n2count++; 171 lapb_transmit_frmr(lapb); 172 } 173 break; 174 } 175 176 lapb_start_t1timer(lapb); 177 } 178