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Commit 006f68b8 authored by Ralf Baechle's avatar Ralf Baechle Committed by David S. Miller
Browse files

[AX.25]: Reference counting for AX.25 routes. 



In the past routes could be freed even though the were possibly in use ...

Signed-off-by: default avatarRalf Baechle DL5RB <ralf@linux-mips.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8dc22d2b

include/net/ax25.h

+15 −9
Original line number Diff line number Diff line
@@ -182,14 +182,26 @@ typedef struct { 


typedef struct ax25_route {

	struct ax25_route	*next;

	atomic_t		ref;

	atomic_t		refcount;

	ax25_address		callsign;

	struct net_device	*dev;

	ax25_digi		*digipeat;

	char			ip_mode;

	struct timer_list	timer;

} ax25_route;



static inline void ax25_hold_route(ax25_route *ax25_rt)

{

	atomic_inc(&ax25_rt->refcount);

}



extern void __ax25_put_route(ax25_route *ax25_rt);



static inline void ax25_put_route(ax25_route *ax25_rt)

{

	if (atomic_dec_and_test(&ax25_rt->refcount))

		__ax25_put_route(ax25_rt);

}



typedef struct {

	char			slave;			/* slave_mode?   */

	struct timer_list	slave_timer;		/* timeout timer */
@@ -348,17 +360,11 @@ extern int ax25_check_iframes_acked(ax25_cb *, unsigned short); 
extern void ax25_rt_device_down(struct net_device *);

extern int  ax25_rt_ioctl(unsigned int, void __user *);

extern struct file_operations ax25_route_fops;

extern ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev);

extern int  ax25_rt_autobind(ax25_cb *, ax25_address *);

extern ax25_route *ax25_rt_find_route(ax25_route *, ax25_address *,

	struct net_device *);

extern struct sk_buff *ax25_rt_build_path(struct sk_buff *, ax25_address *, ax25_address *, ax25_digi *);

extern void ax25_rt_free(void);



static inline void ax25_put_route(ax25_route *ax25_rt)

{

	atomic_dec(&ax25_rt->ref);

}



/* ax25_std_in.c */

extern int  ax25_std_frame_in(ax25_cb *, struct sk_buff *, int);

net/ax25/ax25_ip.c

+15 −8
Original line number Diff line number Diff line
@@ -103,11 +103,13 @@ int ax25_rebuild_header(struct sk_buff *skb) 
{

	struct sk_buff *ourskb;

	unsigned char *bp  = skb->data;

	struct net_device *dev;

	ax25_route *route;

	struct net_device *dev = NULL;

	ax25_address *src, *dst;

	ax25_digi *digipeat = NULL;

	ax25_dev *ax25_dev;

	ax25_route _route, *route = &_route;

	ax25_cb *ax25;

	char ip_mode = ' ';



	dst = (ax25_address *)(bp + 1);

	src = (ax25_address *)(bp + 8);
@@ -115,8 +117,12 @@ int ax25_rebuild_header(struct sk_buff *skb) 
  	if (arp_find(bp + 1, skb))

  		return 1;



	route = ax25_rt_find_route(route, dst, NULL);

	route = ax25_get_route(dst, NULL);

	if (route) {

		digipeat = route->digipeat;

		dev = route->dev;

		ip_mode = route->ip_mode;

	};



	if (dev == NULL)

		dev = skb->dev;
@@ -126,7 +132,7 @@ int ax25_rebuild_header(struct sk_buff *skb) 
	}



	if (bp[16] == AX25_P_IP) {

		if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {

		if (ip_mode == 'V' || (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {

			/*

			 *	We copy the buffer and release the original thereby

			 *	keeping it straight
@@ -172,7 +178,7 @@ int ax25_rebuild_header(struct sk_buff *skb) 
			    ourskb, 

			    ax25_dev->values[AX25_VALUES_PACLEN], 

			    &src_c,

			    &dst_c, route->digipeat, dev);

			    &dst_c, digipeat, dev);

			if (ax25) {

				ax25_cb_put(ax25);

			}
@@ -190,7 +196,7 @@ int ax25_rebuild_header(struct sk_buff *skb) 


	skb_pull(skb, AX25_KISS_HEADER_LEN);



	if (route->digipeat != NULL) {

	if (digipeat != NULL) {

		if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {

			kfree_skb(skb);

			goto put;
@@ -202,6 +208,7 @@ int ax25_rebuild_header(struct sk_buff *skb) 
	ax25_queue_xmit(skb, dev);



put:

	if (route)

		ax25_put_route(route);



  	return 1;

net/ax25/ax25_route.c

+8 −41
Original line number Diff line number Diff line
@@ -41,8 +41,6 @@ 
static ax25_route *ax25_route_list;

static DEFINE_RWLOCK(ax25_route_lock);



static ax25_route *ax25_get_route(ax25_address *, struct net_device *);



void ax25_rt_device_down(struct net_device *dev)

{

	ax25_route *s, *t, *ax25_rt;
@@ -115,7 +113,7 @@ static int ax25_rt_add(struct ax25_routes_struct *route) 
		return -ENOMEM;

	}



	atomic_set(&ax25_rt->ref, 0);

	atomic_set(&ax25_rt->refcount, 1);

	ax25_rt->callsign     = route->dest_addr;

	ax25_rt->dev          = ax25_dev->dev;

	ax25_rt->digipeat     = NULL;
@@ -140,23 +138,10 @@ static int ax25_rt_add(struct ax25_routes_struct *route) 
	return 0;

}



static void ax25_rt_destroy(ax25_route *ax25_rt)

void __ax25_put_route(ax25_route *ax25_rt)

{

	if (atomic_read(&ax25_rt->ref) == 0) {

	kfree(ax25_rt->digipeat);

	kfree(ax25_rt);

		return;

	}



	/*

	 * Uh...  Route is still in use; we can't yet destroy it.  Retry later.

	 */

	init_timer(&ax25_rt->timer);

	ax25_rt->timer.data	= (unsigned long) ax25_rt;

	ax25_rt->timer.function	= (void *) ax25_rt_destroy;

	ax25_rt->timer.expires	= jiffies + 5 * HZ;



	add_timer(&ax25_rt->timer);

}



static int ax25_rt_del(struct ax25_routes_struct *route)
@@ -177,12 +162,12 @@ static int ax25_rt_del(struct ax25_routes_struct *route) 
		    ax25cmp(&route->dest_addr, &s->callsign) == 0) {

			if (ax25_route_list == s) {

				ax25_route_list = s->next;

				ax25_rt_destroy(s);

				ax25_put_route(s);

			} else {

				for (t = ax25_route_list; t != NULL; t = t->next) {

					if (t->next == s) {

						t->next = s->next;

						ax25_rt_destroy(s);

						ax25_put_route(s);

						break;

					}

				}
@@ -362,7 +347,7 @@ struct file_operations ax25_route_fops = { 
 *

 *	Only routes with a reference count of zero can be destroyed.

 */

static ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)

ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev)

{

	ax25_route *ax25_spe_rt = NULL;

	ax25_route *ax25_def_rt = NULL;
@@ -392,7 +377,7 @@ static ax25_route *ax25_get_route(ax25_address *addr, struct net_device *dev) 
		ax25_rt = ax25_spe_rt;



	if (ax25_rt != NULL)

		atomic_inc(&ax25_rt->ref);

		ax25_hold_route(ax25_rt);



	read_unlock(&ax25_route_lock);
@@ -467,24 +452,6 @@ put: 
	return 0;

}



ax25_route *ax25_rt_find_route(ax25_route * route, ax25_address *addr,

	struct net_device *dev)

{

	ax25_route *ax25_rt;



	if ((ax25_rt = ax25_get_route(addr, dev)))

		return ax25_rt;



	route->next     = NULL;

	atomic_set(&route->ref, 1);

	route->callsign = *addr;

	route->dev      = dev;

	route->digipeat = NULL;

	route->ip_mode  = ' ';



	return route;

}



struct sk_buff *ax25_rt_build_path(struct sk_buff *skb, ax25_address *src,

	ax25_address *dest, ax25_digi *digi)

{