i386/linux-2.3.21/net/rose/rose_out.c

   1 /*
   2  *      ROSE release 003
   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  *      ROSE 001        Jonathan(G4KLX) Cloned from nr_out.c
  14  *      ROSE 003        Jonathan(G4KLX) New timer architecture.
  15  *                                      Removed M bit processing.
  16  */
  17
  18 #include <linux/config.h>
  19 #if defined(CONFIG_ROSE) || defined(CONFIG_ROSE_MODULE)
  20 #include <linux/errno.h>
  21 #include <linux/types.h>
  22 #include <linux/socket.h>
  23 #include <linux/in.h>
  24 #include <linux/kernel.h>
  25 #include <linux/sched.h>
  26 #include <linux/timer.h>
  27 #include <linux/string.h>
  28 #include <linux/sockios.h>
  29 #include <linux/net.h>
  30 #include <net/ax25.h>
  31 #include <linux/inet.h>
  32 #include <linux/netdevice.h>
  33 #include <linux/skbuff.h>
  34 #include <net/sock.h>
  35 #include <asm/segment.h>
  36 #include <asm/system.h>
  37 #include <linux/fcntl.h>
  38 #include <linux/mm.h>
  39 #include <linux/interrupt.h>
  40 #include <net/rose.h>
  41
  42 /*
  43  *      This procedure is passed a buffer descriptor for an iframe. It builds
  44  *      the rest of the control part of the frame and then writes it out.
  45  */
  46 static void rose_send_iframe(struct sock *sk, struct sk_buff *skb)
  47 {
  48         if (skb == NULL)
  49                 return;
  50
  51         skb->data[2] |= (sk->protinfo.rose->vr << 5) & 0xE0;
  52         skb->data[2] |= (sk->protinfo.rose->vs << 1) & 0x0E;
  53
  54         rose_start_idletimer(sk);
  55
  56         rose_transmit_link(skb, sk->protinfo.rose->neighbour);
  57 }
  58
  59 void rose_kick(struct sock *sk)
  60 {
  61         struct sk_buff *skb, *skbn;
  62         unsigned short start, end;
  63
  64         if (sk->protinfo.rose->state != ROSE_STATE_3)
  65                 return;
  66
  67         if (sk->protinfo.rose->condition & ROSE_COND_PEER_RX_BUSY)
  68                 return;
  69
  70         if (skb_peek(&sk->write_queue) == NULL)
  71                 return;
  72
  73         start = (skb_peek(&sk->protinfo.rose->ack_queue) == NULL) ? sk->protinfo.rose->va : sk->protinfo.rose->vs;
  74         end   = (sk->protinfo.rose->va + sysctl_rose_window_size) % ROSE_MODULUS;
  75
  76         if (start == end)
  77                 return;
  78
  79         sk->protinfo.rose->vs = start;
  80
  81         /*
  82          * Transmit data until either we're out of data to send or
  83          * the window is full.
  84          */
  85
  86         skb  = skb_dequeue(&sk->write_queue);
  87
  88         do {
  89                 if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
  90                         skb_queue_head(&sk->write_queue, skb);
  91                         break;
  92                 }
  93
  94                 skb_set_owner_w(skbn, sk);
  95
  96                 /*
  97                  * Transmit the frame copy.
  98                  */
  99                 rose_send_iframe(sk, skbn);
 100
 101                 sk->protinfo.rose->vs = (sk->protinfo.rose->vs + 1) % ROSE_MODULUS;
 102
 103                 /*
 104                  * Requeue the original data frame.
 105                  */
 106                 skb_queue_tail(&sk->protinfo.rose->ack_queue, skb);
 107
 108         } while (sk->protinfo.rose->vs != end && (skb = skb_dequeue(&sk->write_queue)) != NULL);
 109
 110         sk->protinfo.rose->vl         = sk->protinfo.rose->vr;
 111         sk->protinfo.rose->condition &= ~ROSE_COND_ACK_PENDING;
 112
 113         rose_stop_timer(sk);
 114 }
 115
 116 /*
 117  * The following routines are taken from page 170 of the 7th ARRL Computer
 118  * Networking Conference paper, as is the whole state machine.
 119  */
 120
 121 void rose_enquiry_response(struct sock *sk)
 122 {
 123         if (sk->protinfo.rose->condition & ROSE_COND_OWN_RX_BUSY)
 124                 rose_write_internal(sk, ROSE_RNR);
 125         else
 126                 rose_write_internal(sk, ROSE_RR);
 127
 128         sk->protinfo.rose->vl         = sk->protinfo.rose->vr;
 129         sk->protinfo.rose->condition &= ~ROSE_COND_ACK_PENDING;
 130
 131         rose_stop_timer(sk);
 132 }
 133
 134 #endif