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 #include <linux/errno.h> 18 #include <linux/types.h> 19 #include <linux/socket.h> 20 #include <linux/in.h> 21 #include <linux/kernel.h> 22 #include <linux/timer.h> 23 #include <linux/string.h> 24 #include <linux/sockios.h> 25 #include <linux/net.h> 26 #include <linux/inet.h> 27 #include <linux/skbuff.h> 28 #include <linux/slab.h> 29 #include <net/sock.h> 30 #include <asm/uaccess.h> 31 #include <asm/system.h> 32 #include <linux/fcntl.h> 33 #include <linux/mm.h> 34 #include <linux/interrupt.h> 35 #include <net/lapb.h> 36 37 /* 38 * This procedure is passed a buffer descriptor for an iframe. It builds 39 * the rest of the control part of the frame and then writes it out. 40 */ 41 static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) 42 { 43 unsigned char *frame; 44 45 if (!skb) 46 return; 47 48 if (lapb->mode & LAPB_EXTENDED) { 49 frame = skb_push(skb, 2); 50 51 frame[0] = LAPB_I; 52 frame[0] |= lapb->vs << 1; 53 frame[1] = poll_bit ? LAPB_EPF : 0; 54 frame[1] |= lapb->vr << 1; 55 } else { 56 frame = skb_push(skb, 1); 57 58 *frame = LAPB_I; 59 *frame |= poll_bit ? LAPB_SPF : 0; 60 *frame |= lapb->vr << 5; 61 *frame |= lapb->vs << 1; 62 } 63 64 #if LAPB_DEBUG > 1 65 printk(KERN_DEBUG "lapb: (%p) S%d TX I(%d) S%d R%d\n", 66 lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); 67 #endif 68 69 lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); 70 } 71 72 void lapb_kick(struct lapb_cb *lapb) 73 { 74 struct sk_buff *skb, *skbn; 75 unsigned short modulus, start, end; 76 77 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; 78 start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; 79 end = (lapb->va + lapb->window) % modulus; 80 81 if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && 82 start != end && skb_peek(&lapb->write_queue)) { 83 lapb->vs = start; 84 85 /* 86 * Dequeue the frame and copy it. 87 */ 88 skb = skb_dequeue(&lapb->write_queue); 89 90 do { 91 if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { 92 skb_queue_head(&lapb->write_queue, skb); 93 break; 94 } 95 96 if (skb->sk) 97 skb_set_owner_w(skbn, skb->sk); 98 99 /* 100 * Transmit the frame copy. 101 */ 102 lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); 103 104 lapb->vs = (lapb->vs + 1) % modulus; 105 106 /* 107 * Requeue the original data frame. 108 */ 109 skb_queue_tail(&lapb->ack_queue, skb); 110 111 } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); 112 113 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 114 115 if (!lapb_t1timer_running(lapb)) 116 lapb_start_t1timer(lapb); 117 } 118 } 119 120 void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) 121 { 122 unsigned char *ptr; 123 124 ptr = skb_push(skb, 1); 125 126 if (lapb->mode & LAPB_MLP) { 127 if (lapb->mode & LAPB_DCE) { 128 if (type == LAPB_COMMAND) 129 *ptr = LAPB_ADDR_C; 130 if (type == LAPB_RESPONSE) 131 *ptr = LAPB_ADDR_D; 132 } else { 133 if (type == LAPB_COMMAND) 134 *ptr = LAPB_ADDR_D; 135 if (type == LAPB_RESPONSE) 136 *ptr = LAPB_ADDR_C; 137 } 138 } else { 139 if (lapb->mode & LAPB_DCE) { 140 if (type == LAPB_COMMAND) 141 *ptr = LAPB_ADDR_A; 142 if (type == LAPB_RESPONSE) 143 *ptr = LAPB_ADDR_B; 144 } else { 145 if (type == LAPB_COMMAND) 146 *ptr = LAPB_ADDR_B; 147 if (type == LAPB_RESPONSE) 148 *ptr = LAPB_ADDR_A; 149 } 150 } 151 152 #if LAPB_DEBUG > 2 153 printk(KERN_DEBUG "lapb: (%p) S%d TX %02X %02X %02X\n", 154 lapb->dev, lapb->state, 155 skb->data[0], skb->data[1], skb->data[2]); 156 #endif 157 158 if (!lapb_data_transmit(lapb, skb)) 159 kfree_skb(skb); 160 } 161 162 void lapb_establish_data_link(struct lapb_cb *lapb) 163 { 164 lapb->condition = 0x00; 165 lapb->n2count = 0; 166 167 if (lapb->mode & LAPB_EXTENDED) { 168 #if LAPB_DEBUG > 1 169 printk(KERN_DEBUG "lapb: (%p) S%d TX SABME(1)\n", 170 lapb->dev, lapb->state); 171 #endif 172 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); 173 } else { 174 #if LAPB_DEBUG > 1 175 printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n", 176 lapb->dev, lapb->state); 177 #endif 178 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); 179 } 180 181 lapb_start_t1timer(lapb); 182 lapb_stop_t2timer(lapb); 183 } 184 185 void lapb_enquiry_response(struct lapb_cb *lapb) 186 { 187 #if LAPB_DEBUG > 1 188 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n", 189 lapb->dev, lapb->state, lapb->vr); 190 #endif 191 192 lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); 193 194 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 195 } 196 197 void lapb_timeout_response(struct lapb_cb *lapb) 198 { 199 #if LAPB_DEBUG > 1 200 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n", 201 lapb->dev, lapb->state, lapb->vr); 202 #endif 203 lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); 204 205 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 206 } 207 208 void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) 209 { 210 if (lapb->vs == nr) { 211 lapb_frames_acked(lapb, nr); 212 lapb_stop_t1timer(lapb); 213 lapb->n2count = 0; 214 } else if (lapb->va != nr) { 215 lapb_frames_acked(lapb, nr); 216 lapb_start_t1timer(lapb); 217 } 218 } 219 220 void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) 221 { 222 if (type == LAPB_COMMAND && pf) 223 lapb_enquiry_response(lapb); 224 } 225