嵌入式Linux

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rose_link.c：源码内容
							/*
 *	ROSE release 003
 *
 *	This code REQUIRES 2.1.15 or higher/ NET3.038
 *
 *	This module:
 *		This module 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.
 *
 *	History
 *	ROSE 001	Jonathan(G4KLX)	Cloned from rose_timer.c
 *	ROSE 003	Jonathan(G4KLX)	New timer architecture.
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/netfilter.h>
#include <net/rose.h>
static void rose_ftimer_expiry(unsigned long);
static void rose_t0timer_expiry(unsigned long);
void rose_start_ftimer(struct rose_neigh *neigh)
{
	del_timer(&neigh->ftimer);
	neigh->ftimer.data     = (unsigned long)neigh;
	neigh->ftimer.function = &rose_ftimer_expiry;
	neigh->ftimer.expires  = jiffies + sysctl_rose_link_fail_timeout;
	add_timer(&neigh->ftimer);
}
void rose_start_t0timer(struct rose_neigh *neigh)
{
	del_timer(&neigh->t0timer);
	neigh->t0timer.data     = (unsigned long)neigh;
	neigh->t0timer.function = &rose_t0timer_expiry;
	neigh->t0timer.expires  = 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);
}
int rose_t0timer_running(struct rose_neigh *neigh)
{
	return timer_pending(&neigh->t0timer);
}
static void rose_ftimer_expiry(unsigned long param)
{
}
static void rose_t0timer_expiry(unsigned long param)
{
	struct rose_neigh *neigh = (struct rose_neigh *)param;
	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;
	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
		rose_call = (ax25_address *)neigh->dev->dev_addr;
	else
		rose_call = &rose_callsign;
	neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
	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;
	if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
		rose_call = (ax25_address *)neigh->dev->dev_addr;
	else
		rose_call = &rose_callsign;
	neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
	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:
			printk(KERN_WARNING "ROSE: received diagnostic #%d - %02X %02X %02Xn", skb->data[3], skb->data[4], skb->data[5], skb->data[6]);
			break;
		default:
			printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000n", 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
 */
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
 */
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 Diagnostic is required.
 */
void rose_transmit_diagnostic(struct rose_neigh *neigh, unsigned char diag)
{
	struct sk_buff *skb;
	unsigned char *dptr;
	int len;
	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 2;
	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 + 2);
	*dptr++ = AX25_P_ROSE;
	*dptr++ = ROSE_GFI;
	*dptr++ = 0x00;
	*dptr++ = ROSE_DIAGNOSTIC;
	*dptr++ = diag;
	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;
	struct net_device *first;
	int faclen = 0;
	len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
	first = rose_dev_first();
	if (first)
		faclen = 6 + AX25_ADDR_LEN + 3 + ROSE_ADDR_LEN;
	
	if ((skb = alloc_skb(len + faclen, GFP_ATOMIC)) == NULL)
		return;
	skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
	dptr = skb_put(skb, ROSE_MIN_LEN + 3 + faclen);
	*dptr++ = AX25_P_ROSE;
	*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
	*dptr++ = ((lci >> 0) & 0xFF);
	*dptr++ = ROSE_CLEAR_REQUEST;
	*dptr++ = cause;
	*dptr++ = diagnostic;
	if (first) {	
		*dptr++ = 0x00;		/* Address length */
		*dptr++ = 4 + AX25_ADDR_LEN + 3 + ROSE_ADDR_LEN; /* Facilities length */
		*dptr++ = 0;
		*dptr++ = FAC_NATIONAL;
		*dptr++ = FAC_NATIONAL_FAIL_CALL;
		*dptr++ = AX25_ADDR_LEN;
		memcpy(dptr, &rose_callsign, AX25_ADDR_LEN);
		dptr += AX25_ADDR_LEN;
		*dptr++ = FAC_NATIONAL_FAIL_ADD;
		*dptr++ = ROSE_ADDR_LEN + 1;
		*dptr++ = ROSE_ADDR_LEN * 2;
		memcpy(dptr, first->dev_addr, ROSE_ADDR_LEN);
	}
	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 0
	if (call_fw_firewall(PF_ROSE, skb->dev, skb->data, NULL, &skb) != FW_ACCEPT) {
		kfree_skb(skb);
		return;
	}
#endif
	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);
		}
	}
}

						