rose_out.c
2.77 KB
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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/gfp.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/rose.h>
/*
* This procedure is passed a buffer descriptor for an iframe. It builds
* the rest of the control part of the frame and then writes it out.
*/
static void rose_send_iframe(struct sock *sk, struct sk_buff *skb)
{
struct rose_sock *rose = rose_sk(sk);
if (skb == NULL)
return;
skb->data[2] |= (rose->vr << 5) & 0xE0;
skb->data[2] |= (rose->vs << 1) & 0x0E;
rose_start_idletimer(sk);
rose_transmit_link(skb, rose->neighbour);
}
void rose_kick(struct sock *sk)
{
struct rose_sock *rose = rose_sk(sk);
struct sk_buff *skb, *skbn;
unsigned short start, end;
if (rose->state != ROSE_STATE_3)
return;
if (rose->condition & ROSE_COND_PEER_RX_BUSY)
return;
if (!skb_peek(&sk->sk_write_queue))
return;
start = (skb_peek(&rose->ack_queue) == NULL) ? rose->va : rose->vs;
end = (rose->va + sysctl_rose_window_size) % ROSE_MODULUS;
if (start == end)
return;
rose->vs = start;
/*
* Transmit data until either we're out of data to send or
* the window is full.
*/
skb = skb_dequeue(&sk->sk_write_queue);
do {
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
skb_queue_head(&sk->sk_write_queue, skb);
break;
}
skb_set_owner_w(skbn, sk);
/*
* Transmit the frame copy.
*/
rose_send_iframe(sk, skbn);
rose->vs = (rose->vs + 1) % ROSE_MODULUS;
/*
* Requeue the original data frame.
*/
skb_queue_tail(&rose->ack_queue, skb);
} while (rose->vs != end &&
(skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
rose->vl = rose->vr;
rose->condition &= ~ROSE_COND_ACK_PENDING;
rose_stop_timer(sk);
}
/*
* The following routines are taken from page 170 of the 7th ARRL Computer
* Networking Conference paper, as is the whole state machine.
*/
void rose_enquiry_response(struct sock *sk)
{
struct rose_sock *rose = rose_sk(sk);
if (rose->condition & ROSE_COND_OWN_RX_BUSY)
rose_write_internal(sk, ROSE_RNR);
else
rose_write_internal(sk, ROSE_RR);
rose->vl = rose->vr;
rose->condition &= ~ROSE_COND_ACK_PENDING;
rose_stop_timer(sk);
}