net/lapb/lapb_out.c

   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/config.h>
  18 #if defined(CONFIG_LAPB) || defined(CONFIG_LAPB_MODULE)
  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/sched.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 <asm/uaccess.h>
  33 #include <asm/system.h>
  34 #include <linux/fcntl.h>
  35 #include <linux/mm.h>
  36 #include <linux/interrupt.h>
  37 #include <net/lapb.h>
  38
  39 /*
  40  *  This procedure is passed a buffer descriptor for an iframe. It builds
  41  *  the rest of the control part of the frame and then writes it out.
  42  */
  43 static void lapb_send_iframe(lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
  44 {
  45         unsigned char *frame;
  46
  47         if (skb == NULL)
  48                 return;
  49
  50         if (lapb->mode & LAPB_EXTENDED) {
  51                 frame = skb_push(skb, 2);
  52
  53                 frame[0] = LAPB_I;
  54                 frame[0] |= (lapb->vs << 1);
  55                 frame[1] = (poll_bit) ? LAPB_EPF : 0;
  56                 frame[1] |= (lapb->vr << 1);
  57         } else {
  58                 frame = skb_push(skb, 1);
  59
  60                 *frame = LAPB_I;
  61                 *frame |= (poll_bit) ? LAPB_SPF : 0;
  62                 *frame |= (lapb->vr << 5);
  63                 *frame |= (lapb->vs << 1);
  64         }
  65
  66 #if LAPB_DEBUG > 1
  67         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);
  68 #endif
  69
  70         lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
  71 }
  72
  73 void lapb_kick(lapb_cb *lapb)
  74 {
  75         struct sk_buff *skb, *skbn;
  76         unsigned short modulus, start, end;
  77
  78         modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
  79
  80         start = (skb_peek(&lapb->ack_queue) == NULL) ? lapb->va : lapb->vs;
  81         end   = (lapb->va + lapb->window) % modulus;
  82
  83         if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) &&
  84             start != end                                &&
  85             skb_peek(&lapb->write_queue) != NULL) {
  86
  87                 lapb->vs = start;
  88
  89                 /*
  90                  * Dequeue the frame and copy it.
  91                  */
  92                 skb  = skb_dequeue(&lapb->write_queue);
  93
  94                 do {
  95                         if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
  96                                 skb_queue_head(&lapb->write_queue, skb);
  97                                 break;
  98                         }
  99
 100                         if (skb->sk != NULL)
 101                                 skb_set_owner_w(skbn, skb->sk);
 102
 103                         /*
 104                          * Transmit the frame copy.
 105                          */
 106                         lapb_send_iframe(lapb, skbn, LAPB_POLLOFF);
 107
 108                         lapb->vs = (lapb->vs + 1) % modulus;
 109
 110                         /*
 111                          * Requeue the original data frame.
 112                          */
 113                         skb_queue_tail(&lapb->ack_queue, skb);
 114
 115                 } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL);
 116
 117                 lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
 118
 119                 if (!lapb_t1timer_running(lapb))
 120                         lapb_start_t1timer(lapb);
 121         }
 122 }
 123
 124 void lapb_transmit_buffer(lapb_cb *lapb, struct sk_buff *skb, int type)
 125 {
 126         unsigned char *ptr;
 127
 128         ptr = skb_push(skb, 1);
 129
 130         if (lapb->mode & LAPB_MLP) {
 131                 if (lapb->mode & LAPB_DCE) {
 132                         if (type == LAPB_COMMAND)
 133                                 *ptr = LAPB_ADDR_C;
 134                         if (type == LAPB_RESPONSE)
 135                                 *ptr = LAPB_ADDR_D;
 136                 } else {
 137                         if (type == LAPB_COMMAND)
 138                                 *ptr = LAPB_ADDR_D;
 139                         if (type == LAPB_RESPONSE)
 140                                 *ptr = LAPB_ADDR_C;
 141                 }
 142         } else {
 143                 if (lapb->mode & LAPB_DCE) {
 144                         if (type == LAPB_COMMAND)
 145                                 *ptr = LAPB_ADDR_A;
 146                         if (type == LAPB_RESPONSE)
 147                                 *ptr = LAPB_ADDR_B;
 148                 } else {
 149                         if (type == LAPB_COMMAND)
 150                                 *ptr = LAPB_ADDR_B;
 151                         if (type == LAPB_RESPONSE)
 152                                 *ptr = LAPB_ADDR_A;
 153                 }
 154         }
 155
 156 #if LAPB_DEBUG > 2
 157         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]);
 158 #endif
 159
 160         if (!lapb_data_transmit(lapb, skb))
 161                 kfree_skb(skb);
 162 }
 163
 164 void lapb_establish_data_link(lapb_cb *lapb)
 165 {
 166         lapb->condition = 0x00;
 167         lapb->n2count   = 0;
 168
 169         if (lapb->mode & LAPB_EXTENDED) {
 170 #if LAPB_DEBUG > 1
 171                 printk(KERN_DEBUG "lapb: (%p) S%d TX SABME(1)\n", lapb->token, lapb->state);
 172 #endif
 173                 lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
 174         } else {
 175 #if LAPB_DEBUG > 1
 176                 printk(KERN_DEBUG "lapb: (%p) S%d TX SABM(1)\n", lapb->token, 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(lapb_cb *lapb)
 186 {
 187 #if LAPB_DEBUG > 1
 188         printk(KERN_DEBUG "lapb: (%p) S%d TX RR(1) R%d\n", lapb->token, lapb->state, lapb->vr);
 189 #endif
 190
 191         lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);
 192
 193         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
 194 }
 195
 196 void lapb_timeout_response(lapb_cb *lapb)
 197 {
 198 #if LAPB_DEBUG > 1
 199         printk(KERN_DEBUG "lapb: (%p) S%d TX RR(0) R%d\n", lapb->token, lapb->state, lapb->vr);
 200 #endif
 201
 202         lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
 203
 204         lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
 205 }
 206
 207 void lapb_check_iframes_acked(lapb_cb *lapb, unsigned short nr)
 208 {
 209         if (lapb->vs == nr) {
 210                 lapb_frames_acked(lapb, nr);
 211                 lapb_stop_t1timer(lapb);
 212                 lapb->n2count = 0;
 213         } else {
 214                 if (lapb->va != nr) {
 215                         lapb_frames_acked(lapb, nr);
 216                         lapb_start_t1timer(lapb);
 217                 }
 218         }
 219 }
 220
 221 void lapb_check_need_response(lapb_cb *lapb, int type, int pf)
 222 {
 223         if (type == LAPB_COMMAND && pf)
 224                 lapb_enquiry_response(lapb);
 225 }
 226
 227 #endif