Eric Lee / smarc-fsl-linux-kernel

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net/rose/rose_out.c 2.8 KB
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1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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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>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
5a0e3ad6a   Tejun Heo   include cleanup: ... 
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  #include <linux/gfp.h>
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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  #include <net/ax25.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/skbuff.h>
  #include <net/sock.h>
  #include <asm/system.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);
  }