rose_route.c

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/*
 *	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 nr_route.c.
 *			Terry(VK2KTJ)	Added support for variable length
 *					address masks.
 *	ROSE 002	Jonathan(G4KLX)	Uprated through routing of packets.
 *					Routing loop detection.
 *	ROSE 003	Jonathan(G4KLX)	New timer architecture.
 *					Added use count to neighbours.
 */

#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 <net/arp.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/fcntl.h>
#include <linux/termios.h>	/* For TIOCINQ/OUTQ */
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/netfilter.h>
#include <linux/init.h>
#include <net/rose.h>

static unsigned int rose_neigh_no = 1;

static struct rose_node  *rose_node_list;
static struct rose_neigh *rose_neigh_list;
static struct rose_route *rose_route_list;

struct rose_neigh *rose_loopback_neigh;

static void rose_remove_neigh(struct rose_neigh *);

/*
 *	Add a new route to a node, and in the process add the node and the
 *	neighbour if it is new.
 */
static int rose_add_node(struct rose_route_struct *rose_route, struct net_device *dev)
{
	struct rose_node  *rose_node, *rose_tmpn, *rose_tmpp;
	struct rose_neigh *rose_neigh;
	unsigned long flags;
	int i;

	for (rose_node = rose_node_list; rose_node != NULL; rose_node = rose_node->next)
		if ((rose_node->mask == rose_route->mask) && (rosecmpm(&rose_route->address, &rose_node->address, rose_route->mask) == 0))
			break;

	if (rose_node != NULL && rose_node->loopback)
		return -EINVAL;

	for (rose_neigh = rose_neigh_list; rose_neigh != NULL; rose_neigh = rose_neigh->next)
		if (ax25cmp(&rose_route->neighbour, &rose_neigh->callsign) == 0 && rose_neigh->dev == dev)
			break;

	if (rose_neigh == NULL) {
		if ((rose_neigh = kmalloc(sizeof(*rose_neigh), GFP_ATOMIC)) == NULL)
			return -ENOMEM;

		rose_neigh->callsign  = rose_route->neighbour;
		rose_neigh->digipeat  = NULL;
		rose_neigh->ax25      = NULL;
		rose_neigh->dev       = dev;
		rose_neigh->count     = 0;
		rose_neigh->use       = 0;
		rose_neigh->dce_mode  = 0;
		rose_neigh->loopback  = 0;
		rose_neigh->number    = rose_neigh_no++;
		rose_neigh->restarted = 0;

		skb_queue_head_init(&rose_neigh->queue);

		init_timer(&rose_neigh->ftimer);
		init_timer(&rose_neigh->t0timer);

		if (rose_route->ndigis != 0) {
			if ((rose_neigh->digipeat = kmalloc(sizeof(ax25_digi), GFP_KERNEL)) == NULL) {
				kfree(rose_neigh);
				return -ENOMEM;
			}

			rose_neigh->digipeat->ndigi      = rose_route->ndigis;
			rose_neigh->digipeat->lastrepeat = -1;

			for (i = 0; i < rose_route->ndigis; i++) {
				rose_neigh->digipeat->calls[i]    = rose_route->digipeaters[i];
				rose_neigh->digipeat->repeated[i] = 0;
			}
		}

		save_flags(flags); cli();
		rose_neigh->next = rose_neigh_list;
		rose_neigh_list  = rose_neigh;
		restore_flags(flags);
	}

	/*
	 * This is a new node to be inserted into the list. Find where it needs
	 * to be inserted into the list, and insert it. We want to be sure
	 * to order the list in descending order of mask size to ensure that
	 * later when we are searching this list the first match will be the
	 * best match.
	 */
	if (rose_node == NULL) {
		rose_tmpn = rose_node_list;
		rose_tmpp = NULL;

		while (rose_tmpn != NULL) {
			if (rose_tmpn->mask > rose_route->mask) {
				rose_tmpp = rose_tmpn;
				rose_tmpn = rose_tmpn->next;
			} else {
				break;
			}
		}

		/* create new node */
		if ((rose_node = kmalloc(sizeof(*rose_node), GFP_ATOMIC)) == NULL)
			return -ENOMEM;

		rose_node->address      = rose_route->address;
		rose_node->mask         = rose_route->mask;
		rose_node->count        = 1;
		rose_node->loopback     = 0;
		rose_node->neighbour[0] = rose_neigh;

		save_flags(flags); cli();

		if (rose_tmpn == NULL) {
			if (rose_tmpp == NULL) {	/* Empty list */
				rose_node_list  = rose_node;
				rose_node->next = NULL;
			} else {
				rose_tmpp->next = rose_node;
				rose_node->next = NULL;
			}
		} else {
			if (rose_tmpp == NULL) {	/* 1st node */
				rose_node->next = rose_node_list;
				rose_node_list  = rose_node;
			} else {
				rose_tmpp->next = rose_node;
				rose_node->next = rose_tmpn;
			}
		}

		restore_flags(flags);

		rose_neigh->count++;

		return 0;
	}

	/* We have space, slot it in */
	if (rose_node->count < 3) {
		rose_node->neighbour[rose_node->count] = rose_neigh;
		rose_node->count++;
		rose_neigh->count++;
	}

	return 0;
}

static void rose_remove_node(struct rose_node *rose_node)
{
	struct rose_node *s;
	unsigned long flags;
	
	save_flags(flags);
	cli();

	if ((s = rose_node_list) == rose_node) {
		rose_node_list = rose_node->next;
		restore_flags(flags);
		kfree(rose_node);
		return;
	}

	while (s != NULL && s->next != NULL) {
		if (s->next == rose_node) {
			s->next = rose_node->next;
			restore_flags(flags);
			kfree(rose_node);
			return;
		}

		s = s->next;
	}

	restore_flags(flags);
}

static void rose_remove_neigh(struct rose_neigh *rose_neigh)
{
	struct rose_neigh *s;
	unsigned long flags;
	struct sk_buff *skb;

	rose_stop_ftimer(rose_neigh);
	rose_stop_t0timer(rose_neigh);

	while ((skb = skb_dequeue(&rose_neigh->queue)) != NULL)
		kfree_skb(skb);

	save_flags(flags); cli();

	if ((s = rose_neigh_list) == rose_neigh) {
		rose_neigh_list = rose_neigh->next;
		restore_flags(flags);
		if (rose_neigh->digipeat != NULL)
			kfree(rose_neigh->digipeat);
		kfree(rose_neigh);
		return;
	}

	while (s != NULL && s->next != NULL) {
		if (s->next == rose_neigh) {
			s->next = rose_neigh->next;
			restore_flags(flags);
			if (rose_neigh->digipeat != NULL)
				kfree(rose_neigh->digipeat);
			kfree(rose_neigh);
			return;
		}

		s = s->next;
	}

	restore_flags(flags);
}

static void rose_remove_route(struct rose_route *rose_route)
{
	struct rose_route *s;
	unsigned long flags;

	if (rose_route->neigh1 != NULL)
		rose_route->neigh1->use--;

	if (rose_route->neigh2 != NULL)
		rose_route->neigh2->use--;

	save_flags(flags); cli();

	if ((s = rose_route_list) == rose_route) {
		rose_route_list = rose_route->next;
		restore_flags(flags);
		kfree(rose_route);
		return;
	}

	while (s != NULL && s->next != NULL) {
		if (s->next == rose_route) {
			s->next = rose_route->next;
			restore_flags(flags);
			kfree(rose_route);
			return;
		}

		s = s->next;
	}

	restore_flags(flags);
}

/*
 *	"Delete" a node. Strictly speaking remove a route to a node. The node
 *	is only deleted if no routes are left to it.
 */
static int rose_del_node(struct rose_route_struct *rose_route, struct net_device *dev)
{
	struct rose_node  *rose_node;
	struct rose_neigh *rose_neigh;
	int i;

	for (rose_node = rose_node_list; rose_node != NULL; rose_node = rose_node->next)
		if ((rose_node->mask == rose_route->mask) && (rosecmpm(&rose_route->address, &rose_node->address, rose_route->mask) == 0))
			break;

	if (rose_node == NULL) return -EINVAL;

	if (rose_node->loopback) return -EINVAL;

	for (rose_neigh = rose_neigh_list; rose_neigh != NULL; rose_neigh = rose_neigh->next)
		if (ax25cmp(&rose_route->neighbour, &rose_neigh->callsign) == 0 && rose_neigh->dev == dev)
			break;

	if (rose_neigh == NULL) return -EINVAL;

	for (i = 0; i < rose_node->count; i++) {
		if (rose_node->neighbour[i] == rose_neigh) {
			rose_neigh->count--;

			if (rose_neigh->count == 0 && rose_neigh->use == 0)
				rose_remove_neigh(rose_neigh);

			rose_node->count--;

			if (rose_node->count == 0) {
				rose_remove_node(rose_node);
			} else {
				switch (i) {
					case 0:
						rose_node->neighbour[0] = rose_node->neighbour[1];
					case 1:
						rose_node->neighbour[1] = rose_node->neighbour[2];
					case 2:
						break;
				}
			}

			return 0;
		}
	}

	return -EINVAL;
}

/*
 *	Add the loopback neighbour.
 */
int rose_add_loopback_neigh(void)
{
	unsigned long flags;

	if ((rose_loopback_neigh = kmalloc(sizeof(struct rose_neigh), GFP_ATOMIC)) == NULL)
		return -ENOMEM;

	rose_loopback_neigh->callsign  = null_ax25_address;
	rose_loopback_neigh->digipeat  = NULL;
	rose_loopback_neigh->ax25      = NULL;
	rose_loopback_neigh->dev       = NULL;
	rose_loopback_neigh->count     = 0;
	rose_loopback_neigh->use       = 0;
	rose_loopback_neigh->dce_mode  = 1;
	rose_loopback_neigh->loopback  = 1;
	rose_loopback_neigh->number    = rose_neigh_no++;
	rose_loopback_neigh->restarted = 1;

	skb_queue_head_init(&rose_loopback_neigh->queue);

	init_timer(&rose_loopback_neigh->ftimer);
	init_timer(&rose_loopback_neigh->t0timer);

	save_flags(flags); cli();
	rose_loopback_neigh->next = rose_neigh_list;
	rose_neigh_list           = rose_loopback_neigh;
	restore_flags(flags);

	return 0;
}

/*
 *	Add a loopback node.
 */
int rose_add_loopback_node(rose_address *address)
{
	struct rose_node *rose_node;
	unsigned long flags;

	for (rose_node = rose_node_list; rose_node != NULL; rose_node = rose_node->next)
		if ((rose_node->mask == 10) && (rosecmpm(address, &rose_node->address, 10) == 0) && rose_node->loopback)
			break;

	if (rose_node != NULL) return 0;
	
	if ((rose_node = kmalloc(sizeof(*rose_node), GFP_ATOMIC)) == NULL)
		return -ENOMEM;

	rose_node->address      = *address;
	rose_node->mask         = 10;
	rose_node->count        = 1;
	rose_node->loopback     = 1;
	rose_node->neighbour[0] = rose_loopback_neigh;

	/* Insert at the head of list. Address is always mask=10 */
	save_flags(flags); cli();
	rose_node->next = rose_node_list;
	rose_node_list  = rose_node;
	restore_flags(flags);

	rose_loopback_neigh->count++;

	return 0;
}

/*
 *	Delete a loopback node.
 */
void rose_del_loopback_node(rose_address *address)
{
	struct rose_node *rose_node;

	for (rose_node = rose_node_list; rose_node != NULL; rose_node = rose_node->next)
		if ((rose_node->mask == 10) && (rosecmpm(address, &rose_node->address, 10) == 0) && rose_node->loopback)
			break;

	if (rose_node == NULL) return;

	rose_remove_node(rose_node);

	rose_loopback_neigh->count--;
}

/*
 *	A device has been removed. Remove its routes and neighbours.
 */
void rose_rt_device_down(struct net_device *dev)
{
	struct rose_neigh *s, *rose_neigh = rose_neigh_list;
	struct rose_node  *t, *rose_node;
	int i;

	while (rose_neigh != NULL) {
		s          = rose_neigh;
		rose_neigh = rose_neigh->next;

		if (s->dev == dev) {
			rose_node = rose_node_list;

			while (rose_node != NULL) {
				t         = rose_node;
				rose_node = rose_node->next;

				for (i = 0; i < t->count; i++) {
					if (t->neighbour[i] == s) {
						t->count--;

						switch (i) {
							case 0:
								t->neighbour[0] = t->neighbour[1];
							case 1:
								t->neighbour[1] = t->neighbour[2];
							case 2:
								break;
						}
					}
				}

				if (t->count <= 0)
					rose_remove_node(t);
			}

			rose_remove_neigh(s);
		}
	}
}

/*
 *	A device has been removed. Remove its links.
 */
void rose_route_device_down(struct net_device *dev)
{
	struct rose_route *s, *rose_route = rose_route_list;

	while (rose_route != NULL) {
		s          = rose_route;
		rose_route = rose_route->next;

		if (s->neigh1->dev == dev || s->neigh2->dev == dev)
			rose_remove_route(s);
	}
}

/*
 *	Clear all nodes and neighbours out, except for neighbours with
 *	active connections going through them.
 *  Do not clear loopback neighbour and nodes.
 */
static int rose_clear_routes(void)
{
	struct rose_neigh *s, *rose_neigh = rose_neigh_list;
	struct rose_node  *t, *rose_node  = rose_node_list;

	while (rose_node != NULL) {
		t         = rose_node;
		rose_node = rose_node->next;
		if (!t->loopback)
			rose_remove_node(t);
	}

	while (rose_neigh != NULL) {
		s          = rose_neigh;
		rose_neigh = rose_neigh->next;

		if (s->use == 0 && !s->loopback) {
			s->count = 0;
			rose_remove_neigh(s);
		}
	}

	return 0;
}

/*
 *	Check that the device given is a valid AX.25 interface that is "up".
 */
struct net_device *rose_ax25_dev_get(char *devname)
{
	struct net_device *dev;

	if ((dev = dev_get_by_name(devname)) == NULL)
		return NULL;

	if ((dev->flags & IFF_UP) && dev->type == ARPHRD_AX25)
		return dev;

	dev_put(dev);
	return NULL;
}

/*
 *	Find the first active ROSE device, usually "rose0".
 */
struct net_device *rose_dev_first(void)
{
	struct net_device *dev, *first = NULL;

	read_lock(&dev_base_lock);
	for (dev = dev_base; dev != NULL; dev = dev->next) {
		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_ROSE)
			if (first == NULL || strncmp(dev->name, first->name, 3) < 0)
				first = dev;
	}
	read_unlock(&dev_base_lock);

	return first;
}

/*
 *	Find the ROSE device for the given address.
 */
struct net_device *rose_dev_get(rose_address *addr)
{
	struct net_device *dev;

	read_lock(&dev_base_lock);
	for (dev = dev_base; dev != NULL; dev = dev->next) {
		if ((dev->flags & IFF_UP) && dev->type == ARPHRD_ROSE && rosecmp(addr, (rose_address *)dev->dev_addr) == 0) {
			dev_hold(dev);
			goto out;
		}
	}
out:
	read_unlock(&dev_base_lock);
	return dev;
}

static int rose_dev_exists(rose_address *addr)
{
	struct net_device *dev;