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/sched.h> 23#include <linux/timer.h> 24#include <linux/string.h> 25#include <linux/sockios.h> 26#include <linux/net.h> 27#include <linux/inet.h> 28#include <linux/skbuff.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 */ 41static void lapb_send_iframe(lapb_cb *lapb, struct sk_buff *skb, int poll_bit) 42{ 43 unsigned char *frame; 44 45 if (skb == NULL) 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", lapb->token, lapb->state, poll_bit, lapb->vs, lapb->vr); 66#endif 67 68 lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); 69} 70 71void lapb_kick(lapb_cb *lapb) 72{ 73 struct sk_buff *skb, *skbn; 74 unsigned short modulus, start, end; 75 76 modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; 77 78 start = (skb_peek(&lapb->ack_queue) == NULL) ? lapb->va : lapb->vs; 79 end = (lapb->va + lapb->window) % modulus; 80 81 if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && 82 start != end && 83 skb_peek(&lapb->write_queue) != NULL) { 84 85 lapb->vs = start; 86 87 /* 88 * Dequeue the frame and copy it. 89 */ 90 skb = skb_dequeue(&lapb->write_queue); 91 92 do { 93 if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { 94 skb_queue_head(&lapb->write_queue, skb); 95 break; 96 } 97 98 if (skb->sk != NULL) 99 skb_set_owner_w(skbn, skb->sk); 100 101 /* 102 * Transmit the frame copy. 103 */ 104 lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); 105 106 lapb->vs = (lapb->vs + 1) % modulus; 107 108 /* 109 * Requeue the original data frame. 110 */ 111 skb_queue_tail(&lapb->ack_queue, skb); 112 113 } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); 114 115 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 116 117 if (!lapb_t1timer_running(lapb)) 118 lapb_start_t1timer(lapb); 119 } 120} 121 122void lapb_transmit_buffer(lapb_cb *lapb, struct sk_buff *skb, int type) 123{ 124 unsigned char *ptr; 125 126 ptr = skb_push(skb, 1); 127 128 if (lapb->mode & LAPB_MLP) { 129 if (lapb->mode & LAPB_DCE) { 130 if (type == LAPB_COMMAND) 131 *ptr = LAPB_ADDR_C; 132 if (type == LAPB_RESPONSE) 133 *ptr = LAPB_ADDR_D; 134 } else { 135 if (type == LAPB_COMMAND) 136 *ptr = LAPB_ADDR_D; 137 if (type == LAPB_RESPONSE) 138 *ptr = LAPB_ADDR_C; 139 } 140 } else { 141 if (lapb->mode & LAPB_DCE) { 142 if (type == LAPB_COMMAND) 143 *ptr = LAPB_ADDR_A; 144 if (type == LAPB_RESPONSE) 145 *ptr = LAPB_ADDR_B; 146 } else { 147 if (type == LAPB_COMMAND) 148 *ptr = LAPB_ADDR_B; 149 if (type == LAPB_RESPONSE) 150 *ptr = LAPB_ADDR_A; 151 } 152 } 153 154#if LAPB_DEBUG > 2 155 printk(KERN_DEBUG "lapb: (%p) S%d TX %02X %02X %02X\n", lapb->token, lapb->state, 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 162void lapb_establish_data_link(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", lapb->token, lapb->state); 170#endif 171 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); 172 } else { 173#if LAPB_DEBUG > 1 174 printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n", lapb->token, lapb->state); 175#endif 176 lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); 177 } 178 179 lapb_start_t1timer(lapb); 180 lapb_stop_t2timer(lapb); 181} 182 183void lapb_enquiry_response(lapb_cb *lapb) 184{ 185#if LAPB_DEBUG > 1 186 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n", lapb->token, lapb->state, lapb->vr); 187#endif 188 189 lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); 190 191 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 192} 193 194void lapb_timeout_response(lapb_cb *lapb) 195{ 196#if LAPB_DEBUG > 1 197 printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n", lapb->token, lapb->state, lapb->vr); 198#endif 199 200 lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); 201 202 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; 203} 204 205void lapb_check_iframes_acked(lapb_cb *lapb, unsigned short nr) 206{ 207 if (lapb->vs == nr) { 208 lapb_frames_acked(lapb, nr); 209 lapb_stop_t1timer(lapb); 210 lapb->n2count = 0; 211 } else { 212 if (lapb->va != nr) { 213 lapb_frames_acked(lapb, nr); 214 lapb_start_t1timer(lapb); 215 } 216 } 217} 218 219void lapb_check_need_response(lapb_cb *lapb, int type, int pf) 220{ 221 if (type == LAPB_COMMAND && pf) 222 lapb_enquiry_response(lapb); 223} 224