text: /*
   * 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/jiffies.h>
  #include <linux/timer.h>
  #include <linux/string.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/slab.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>
  
  static void rose_ftimer_expiry(struct timer_list *);
  static void rose_t0timer_expiry(struct timer_list *);
  
  static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
  static void rose_transmit_restart_request(struct rose_neigh *neigh);
  
  void rose_start_ftimer(struct rose_neigh *neigh)
  {
  	del_timer(&neigh->ftimer);
  
  	neigh->ftimer.function = (TIMER_FUNC_TYPE)rose_ftimer_expiry;
  	neigh->ftimer.expires  =
  		jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
  
  	add_timer(&neigh->ftimer);
  }
  
  static void rose_start_t0timer(struct rose_neigh *neigh)
  {
  	del_timer(&neigh->t0timer);
  
  	neigh->t0timer.function = (TIMER_FUNC_TYPE)rose_t0timer_expiry;
  	neigh->t0timer.expires  =
  		jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
  
  	add_timer(&neigh->t0timer);
  }
  
  void rose_stop_ftimer(struct rose_neigh *neigh)
  {
  	del_timer(&neigh->ftimer);
  }
  
  void rose_stop_t0timer(struct rose_neigh *neigh)
  {
  	del_timer(&neigh->t0timer);
  }
  
  int rose_ftimer_running(struct rose_neigh *neigh)
  {
  	return timer_pending(&neigh->ftimer);
  }
  
  static int rose_t0timer_running(struct rose_neigh *neigh)
  {
  	return timer_pending(&neigh->t0timer);
  }
  
  static void rose_ftimer_expiry(struct timer_list *t)
  {
  }
  
  static void rose_t0timer_expiry(struct timer_list *t)
  {
  	struct rose_neigh *neigh = from_timer(neigh, t, t0timer);
  
  	rose_transmit_restart_request(neigh);
  
  	neigh->dce_mode = 0;
  
  	rose_start_t0timer(neigh);
  }
  
  /*
   *	Interface to ax25_send_frame. Changes my level 2 callsign depending
   *	on whether we have a global ROSE callsign or use the default port
   *	callsign.
   */
  static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
  {
  	ax25_address *rose_call;
  	ax25_cb *ax25s;
  
  	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
  		rose_call = (ax25_address *)neigh->dev->dev_addr;
  	else
  		rose_call = &rose_callsign;
  
  	ax25s = neigh->ax25;
  	neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
  	if (ax25s)
  		ax25_cb_put(ax25s);
  
  	return neigh->ax25 != NULL;
  }
  
  /*
   *	Interface to ax25_link_up. Changes my level 2 callsign depending
   *	on whether we have a global ROSE callsign or use the default port
   *	callsign.
   */
  static int rose_link_up(struct rose_neigh *neigh)
  {
  	ax25_address *rose_call;
  	ax25_cb *ax25s;
  
  	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
  		rose_call = (ax25_address *)neigh->dev->dev_addr;
  	else
  		rose_call = &rose_callsign;
  
  	ax25s = neigh->ax25;
  	neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
  	if (ax25s)
  		ax25_cb_put(ax25s);
  
  	return neigh->ax25 != NULL;
  }
  
  /*
   *	This handles all restart and diagnostic frames.
   */
  void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
  {
  	struct sk_buff *skbn;
  
  	switch (frametype) {
  	case ROSE_RESTART_REQUEST:
  		rose_stop_t0timer(neigh);
  		neigh->restarted = 1;
  		neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
  		rose_transmit_restart_confirmation(neigh);
  		break;
  
  	case ROSE_RESTART_CONFIRMATION:
  		rose_stop_t0timer(neigh);
  		neigh->restarted = 1;
  		break;
  
  	case ROSE_DIAGNOSTIC:
  		pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
  			skb->data + 4);
  		break;
  
  	default:
  		printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
  		break;
  	}
  
  	if (neigh->restarted) {
  		while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
  			if (!rose_send_frame(skbn, neigh))
  				kfree_skb(skbn);
  	}
  }
  
  /*
   *	This routine is called when a Restart Request is needed
   */
  static void rose_transmit_restart_request(struct rose_neigh *neigh)
  {
  	struct sk_buff *skb;
  	unsigned char *dptr;
  	int len;
  
  	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
  
  	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
  		return;
  
  	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
  
  	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
  
  	*dptr++ = AX25_P_ROSE;
  	*dptr++ = ROSE_GFI;
  	*dptr++ = 0x00;
  	*dptr++ = ROSE_RESTART_REQUEST;
  	*dptr++ = ROSE_DTE_ORIGINATED;
  	*dptr++ = 0;
  
  	if (!rose_send_frame(skb, neigh))
  		kfree_skb(skb);
  }
  
  /*
   * This routine is called when a Restart Confirmation is needed
   */
  static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
  {
  	struct sk_buff *skb;
  	unsigned char *dptr;
  	int len;
  
  	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
  
  	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
  		return;
  
  	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
  
  	dptr = skb_put(skb, ROSE_MIN_LEN + 1);
  
  	*dptr++ = AX25_P_ROSE;
  	*dptr++ = ROSE_GFI;
  	*dptr++ = 0x00;
  	*dptr++ = ROSE_RESTART_CONFIRMATION;
  
  	if (!rose_send_frame(skb, neigh))
  		kfree_skb(skb);
  }
  
  /*
   * This routine is called when a Clear Request is needed outside of the context
   * of a connected socket.
   */
  void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
  {
  	struct sk_buff *skb;
  	unsigned char *dptr;
  	int len;
  
  	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
  
  	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
  		return;
  
  	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
  
  	dptr = skb_put(skb, ROSE_MIN_LEN + 3);
  
  	*dptr++ = AX25_P_ROSE;
  	*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
  	*dptr++ = ((lci >> 0) & 0xFF);
  	*dptr++ = ROSE_CLEAR_REQUEST;
  	*dptr++ = cause;
  	*dptr++ = diagnostic;
  
  	if (!rose_send_frame(skb, neigh))
  		kfree_skb(skb);
  }
  
  void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
  {
  	unsigned char *dptr;
  
  	if (neigh->loopback) {
  		rose_loopback_queue(skb, neigh);
  		return;
  	}
  
  	if (!rose_link_up(neigh))
  		neigh->restarted = 0;
  
  	dptr = skb_push(skb, 1);
  	*dptr++ = AX25_P_ROSE;
  
  	if (neigh->restarted) {
  		if (!rose_send_frame(skb, neigh))
  			kfree_skb(skb);
  	} else {
  		skb_queue_tail(&neigh->queue, skb);
  
  		if (!rose_t0timer_running(neigh)) {
  			rose_transmit_restart_request(neigh);
  			neigh->dce_mode = 0;
  			rose_start_t0timer(neigh);
  		}
  	}
  }
  