1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * LAPB release 002 4 * 5 * This code REQUIRES 2.1.15 or higher/ NET3.038 6 * 7 * History 8 * LAPB 001 Jonathan Naylor Started Coding 9 * LAPB 002 Jonathan Naylor New timer architecture. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/errno.h> 15 #include <linux/types.h> 16 #include <linux/socket.h> 17 #include <linux/in.h> 18 #include <linux/kernel.h> 19 #include <linux/jiffies.h> 20 #include <linux/timer.h> 21 #include <linux/string.h> 22 #include <linux/sockios.h> 23 #include <linux/net.h> 24 #include <linux/inet.h> 25 #include <linux/skbuff.h> 26 #include <net/sock.h> 27 #include <linux/uaccess.h> 28 #include <linux/fcntl.h> 29 #include <linux/mm.h> 30 #include <linux/interrupt.h> 31 #include <net/lapb.h> 32 33 static void lapb_t1timer_expiry(struct timer_list *); 34 static void lapb_t2timer_expiry(struct timer_list *); 35 36 void lapb_start_t1timer(struct lapb_cb *lapb) 37 { 38 del_timer(&lapb->t1timer); 39 40 lapb->t1timer.function = lapb_t1timer_expiry; 41 lapb->t1timer.expires = jiffies + lapb->t1; 42 43 add_timer(&lapb->t1timer); 44 } 45 46 void lapb_start_t2timer(struct lapb_cb *lapb) 47 { 48 del_timer(&lapb->t2timer); 49 50 lapb->t2timer.function = lapb_t2timer_expiry; 51 lapb->t2timer.expires = jiffies + lapb->t2; 52 53 add_timer(&lapb->t2timer); 54 } 55 56 void lapb_stop_t1timer(struct lapb_cb *lapb) 57 { 58 del_timer(&lapb->t1timer); 59 } 60 61 void lapb_stop_t2timer(struct lapb_cb *lapb) 62 { 63 del_timer(&lapb->t2timer); 64 } 65 66 int lapb_t1timer_running(struct lapb_cb *lapb) 67 { 68 return timer_pending(&lapb->t1timer); 69 } 70 71 static void lapb_t2timer_expiry(struct timer_list *t) 72 { 73 struct lapb_cb *lapb = from_timer(lapb, t, t2timer); 74 75 if (lapb->condition & LAPB_ACK_PENDING_CONDITION) { 76 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 77 lapb_timeout_response(lapb); 78 } 79 } 80 81 static void lapb_t1timer_expiry(struct timer_list *t) 82 { 83 struct lapb_cb *lapb = from_timer(lapb, t, t1timer); 84 85 switch (lapb->state) { 86 87 /* 88 * If we are a DCE, keep going DM .. DM .. DM 89 */ 90 case LAPB_STATE_0: 91 if (lapb->mode & LAPB_DCE) 92 lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE); 93 break; 94 95 /* 96 * Awaiting connection state, send SABM(E), up to N2 times. 97 */ 98 case LAPB_STATE_1: 99 if (lapb->n2count == lapb->n2) { 100 lapb_clear_queues(lapb); 101 lapb->state = LAPB_STATE_0; 102 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 103 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); 104 return; 105 } else { 106 lapb->n2count++; 107 if (lapb->mode & LAPB_EXTENDED) { 108 lapb_dbg(1, "(%p) S1 TX SABME(1)\n", 109 lapb->dev); 110 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); 111 } else { 112 lapb_dbg(1, "(%p) S1 TX SABM(1)\n", 113 lapb->dev); 114 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); 115 } 116 } 117 break; 118 119 /* 120 * Awaiting disconnection state, send DISC, up to N2 times. 121 */ 122 case LAPB_STATE_2: 123 if (lapb->n2count == lapb->n2) { 124 lapb_clear_queues(lapb); 125 lapb->state = LAPB_STATE_0; 126 lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT); 127 lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); 128 return; 129 } else { 130 lapb->n2count++; 131 lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev); 132 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 133 } 134 break; 135 136 /* 137 * Data transfer state, restransmit I frames, up to N2 times. 138 */ 139 case LAPB_STATE_3: 140 if (lapb->n2count == lapb->n2) { 141 lapb_clear_queues(lapb); 142 lapb->state = LAPB_STATE_0; 143 lapb_stop_t2timer(lapb); 144 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 145 lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); 146 return; 147 } else { 148 lapb->n2count++; 149 lapb_requeue_frames(lapb); 150 lapb_kick(lapb); 151 } 152 break; 153 154 /* 155 * Frame reject state, restransmit FRMR frames, up to N2 times. 156 */ 157 case LAPB_STATE_4: 158 if (lapb->n2count == lapb->n2) { 159 lapb_clear_queues(lapb); 160 lapb->state = LAPB_STATE_0; 161 lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); 162 lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev); 163 return; 164 } else { 165 lapb->n2count++; 166 lapb_transmit_frmr(lapb); 167 } 168 break; 169 } 170 171 lapb_start_t1timer(lapb); 172 } 173