/*
 * ax25_route.c: Routing table management for NEW-AX.25
 *
 * Authors:      Jens David (DG1KJD), Matthias Welwarsky (DG2FEF), Jonathan (G4K
 *               Alan Cox (GW4PTS), Joerg (DL1BKE), et al
 *
 * Comment:
 *
 * Changelog:
 *
 * License:      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.
 */

#include <linux/config.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <net/sock.h>
#include <net/ax25_uid.h>

#include "af_ax25.h"
#include "ax25_core.h"
#include "ax25_route.h"

static struct ax25_route *ax25_route = NULL;
rwlock_t ax25_rt_lock = RW_LOCK_UNLOCKED;

/*
 * delete all routes on a given device
 */
void ax25_rt_device_down(struct net_device *dev)
{
	struct ax25_route *this, *last;

	write_lock(&ax25_rt_lock);

	this = ax25_route;
	last = NULL;

	while (this) {
		if (this->dev != dev) {
			last = this;
			this = this->next;
			continue;
		}
		if (!last) {
			ax25_route = this->next;
			kfree(this);
			this = ax25_route;
			continue;
		}
		last->next = this->next;
		kfree(this);
		this = last->next;
	}

	write_unlock(&ax25_rt_lock);
}

int ax25_add_route(ax25_path_t *path, struct net_device *dev)
{
	struct ax25_route *this;

	write_lock(&ax25_rt_lock);

	for (this = ax25_route; this; this = this->next) {
		if (ax25cmp(&this->path.addr, &path->addr) == 0) {
			this->path = *path;
			this->dev  = dev;
			return 0;
		}
	}

	if ((this = (struct ax25_route *)kmalloc(sizeof(struct ax25_route), GFP_KERNEL)) == NULL)
		return -ENOMEM;
	this->path    = *path;
	this->dev     = dev;
	this->ip_mode = ' ';
        this->next    = ax25_route;
	ax25_route    = this;

	write_unlock(&ax25_rt_lock);

	return 0;
}

int ax25_del_route(ax25_address *addr)
{
	struct ax25_route *this, *last;

	write_lock(&ax25_rt_lock);

	this = ax25_route;
	last = NULL;
	while (this != NULL) {
		if (ax25cmp(&this->path.addr, addr) != 0) {
			last = this;
			this = this->next;
			continue;
		}
		if (!last) {
			ax25_route = this->next;
			kfree(this);
			return 0;
		}
		last->next = this->next;
		kfree(this);
		return 0;
	}

	write_unlock(&ax25_rt_lock);

	return -EINVAL;
}

int ax25_ipopt_route(ax25_address *addr, unsigned char opt)
{
	struct ax25_route *this;
	int err = -EINVAL;

	write_lock(&ax25_rt_lock);

	for (this = ax25_route; this; this = this->next) {
		if (ax25cmp(&this->path.addr, addr) == 0) {
			switch(opt) {
			case ' ':
			case 'D':
			case 'V':
			case 'C':
				this->ip_mode = opt;
				err = 0;
				break;
			}
		}
	}

	write_unlock(&ax25_rt_lock);

	return err;
}

int ax25_rt_ioctl(unsigned int cmd, void *arg)
{
	struct ax25_routes_struct route;
	struct ax25_route_opt_struct rt_option;
	struct net_device *dev;
	ax25_path_t ax25_path;
	int err = -EINVAL;
	int i;

	switch (cmd) {
	case SIOCADDRT:
		/* do some sanity checks */
		if (copy_from_user(&route, arg, sizeof(route))) {
			err = -EFAULT;
			break;
		}
		if ((dev = ax25rtr_get_dev(&route.port_addr)) == NULL)
			break;
		if (route.digi_count > AX25_MAX_DIGIS)
			break;

		ax25_path.addr = route.dest_addr;
		for (i = 0; i < route.digi_count; i++)
			ax25_path.digipeater[i] = route.digi_addr[i];
		ax25_path.dcount = route.digi_count;
		err = ax25_add_route(&ax25_path, dev);
		break;

	case SIOCDELRT:
		/* sanity checks */
		if (copy_from_user(&route, arg, sizeof(route))) {
			err = -EFAULT;
			break;
		}
		if ((dev = ax25rtr_get_dev(&route.port_addr)) == NULL)
			break;

		err = ax25_del_route(&route.dest_addr);
		break;

	case SIOCAX25OPTRT:
		/* sanity checks */
		if (copy_from_user(&rt_option, arg, sizeof(rt_option))) {
			err = -EFAULT;
			break;
		}
		if ((dev = ax25rtr_get_dev(&rt_option.port_addr)) == NULL)
			break;

		switch (rt_option.cmd) {
		case AX25_SET_RT_IPMODE:
			err = ax25_ipopt_route(&rt_option.dest_addr, rt_option.arg);
			break;
		}
	}

	return err;
}

int ax25_rt_get_info(char *buffer, char **start, off_t offset, int length)
{
	struct ax25_route *ax25_rt;
	int len     = 0;
	off_t pos   = 0;
	off_t begin = 0;
	char *callsign;
	int i;
  
	read_lock(&ax25_rt_lock);

	len += sprintf(buffer, "callsign  dev  mode digipeaters\n");

	for (ax25_rt = ax25_route; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
		if (ax25cmp(&ax25_rt->path.addr, &null_ax25_address) == 0)
			callsign = "default";
		else
			callsign = ax2asc(&ax25_rt->path.addr);
		len += sprintf(buffer + len, "%-9s %-4s",
			       callsign,
			       ax25_rt->dev ? ax25_rt->dev->name : "???");

		switch (ax25_rt->ip_mode) {
		case 'V':
			len += sprintf(buffer + len, "   vc");
			break;
		case 'D':
			len += sprintf(buffer + len, "   dg");
			break;
		case 'C':
			len += sprintf(buffer + len, "   vj");
			break;
		default:
			len += sprintf(buffer + len, "    *");
			break;
		}

		for (i = 0; i < ax25_rt->path.dcount; i++)
			len += sprintf(buffer + len, " %s", ax2asc(&ax25_rt->path.digipeater[i]));

		len += sprintf(buffer + len, "\n");

		pos = begin + len;

		if (pos < offset) {
			len   = 0;
			begin = pos;
		}

		if (pos > offset + length)
			break;
	}

	read_unlock(&ax25_rt_lock);

	*start = buffer + (offset - begin);
	len   -= (offset - begin);

	if (len > length) len = length;

	return len;
} 

/*
 *	Find AX.25 route
 */
struct ax25_route *ax25_find_route(ax25_address *addr)
{
	struct ax25_route *ax25_spe_rt = NULL;
	struct ax25_route *ax25_def_rt = NULL;
	struct ax25_route *ax25_rt;

	read_lock(&ax25_rt_lock);

	for (ax25_rt = ax25_route; ax25_rt != NULL; ax25_rt = ax25_rt->next) {
		if (ax25cmp(&ax25_rt->path.addr, addr) == 0)
			ax25_spe_rt = ax25_rt;
		if (ax25cmp(&ax25_rt->path.addr, &null_ax25_address) == 0)
			ax25_def_rt = ax25_rt;
	}

	if (ax25_spe_rt != NULL)
		return ax25_spe_rt;

	read_unlock(&ax25_rt_lock);

	return ax25_def_rt;
}

/*
 * 	MW: This is the core of the digipeating stuff. For a given
 * 	src/dest it finds the appropriate device and digipeaterpath
 *      to route to.
 */
struct net_device *ax25_rt_set_addr(ax25_addr_t *out, ax25_addr_t *in, struct net_device *dev, struct net_device *out_dev)
{
	struct ax25_route *ax25rt;
	ax25_address *next_dest;
	ax25_address *dptr;
	int more_digis;

	/*
	 * find out where to go next. we route the packet either
	 * to the next digi behind us or to the destination. We
	 * NEVER route to the destination if there are digipeaters
	 * left.
	 */
	more_digis = in->dcount - (in->lastrepeat+2);
	if (more_digis > 0)
		next_dest = &in->digipeater[in->lastrepeat+2];
	else
		next_dest = &in->dest;

	/*
	 * check for a route.
	 */
	if ((ax25rt = ax25_find_route(next_dest)) != NULL)
		out_dev = ax25rt->dev;

	/*
	 * set up the digipeater path.
	 * for now we just copy the path of the incoming SABM
	 * up to the digipeater before us, if any.
	 */
	out->dest = in->dest;
	out->src  = in->src;

	if (in->lastrepeat >= 0)
		memcpy(out->digipeater, in->digipeater, sizeof(ax25_address) * (in->lastrepeat+1));

	/*
	 * then we fill in the callsign of the device the frame
	 * came in.
	 */
	out->lastrepeat = in->lastrepeat+1;
	out->dcount     = out->lastrepeat+1;
	dptr    = &out->digipeater[(int) out->lastrepeat];
	*dptr++ = *((ax25_address *)dev->dev_addr);

	/*
	 * insert the route to next_dest, if any.
	 */
	if (ax25rt != NULL && ax25rt->path.dcount != 0) {
		memcpy(dptr, ax25rt->path.digipeater, sizeof(ax25_address) * ax25rt->path.dcount);
		out->dcount += ax25rt->path.dcount;
		dptr += ax25rt->path.dcount;
	}

	/*
	 * append next_dest if we route to a waypoint
	 */
	while (more_digis-- > 0 && out->dcount <= AX25_MAX_DIGIS) {
		*dptr++ = *next_dest++;
		out->dcount++;
	}
	return out_dev;
}

/*
 *      Find the device to use
 */
int ax25_rt_fillin_dev(ax25_cb *ax25, ax25_address *addr)
{
	struct ax25_route *ax25_rt;

	if ((ax25_rt = ax25_find_route(addr)) == NULL)
		return -EHOSTUNREACH;

/* 	ax25_remove_cb(ax25); */
	ax25_fillin_cb(ax25, ax25_rt->dev);
/* 	ax25_insert_cb(ax25); */

	return 0;
}

/*
 *	Return the IP mode of a given callsign/device pair.
 */
char ax25_rt_mode_get(ax25_address *callsign)
{
	struct ax25_route *ax25_rt;

	read_lock(&ax25_rt_lock);

	for (ax25_rt = ax25_route; ax25_rt != NULL; ax25_rt = ax25_rt->next)
		if (ax25cmp(&ax25_rt->path.addr, callsign) == 0)
			return ax25_rt->ip_mode;

	read_unlock(&ax25_rt_lock);

	return ' ';
}



/*
 *	Free all memory associated with routing and device structures.
 */
void ax25_rt_free(void)
{
	struct ax25_route *s, *ax25_rt = ax25_route;

	write_lock(&ax25_rt_lock);

	while (ax25_rt != NULL) {
		s       = ax25_rt;
		ax25_rt = ax25_rt->next;
		kfree(s);
	}

	write_unlock(&ax25_rt_lock);
}