[AX25]: Fix ax25_cb locking.

- ax25_cb's use refcounting
- the ax25_cb list uses hlists
- Lots of socket locking.

include/net/ax25.h

@@ -10,6 +10,7 @@
 #include <linux/ax25.h>
 #include <linux/spinlock.h>
 #include <linux/timer.h>
+#include <linux/list.h>
 #include <asm/atomic.h>
 
 #define	AX25_T1CLAMPLO  		1
@@ -180,7 +181,7 @@ typedef struct ax25_dev {
 } ax25_dev;
 
 typedef struct ax25_cb {
-	struct ax25_cb		*next;
+	struct hlist_node	ax25_node;
 	ax25_address		source_addr, dest_addr;
 	ax25_digi		*digipeat;
 	ax25_dev		*ax25_dev;
@@ -197,17 +198,32 @@ typedef struct ax25_cb {
 	struct sk_buff_head	ack_queue;
 	struct sk_buff_head	frag_queue;
 	unsigned char		window;
-	struct timer_list	timer;
+	struct timer_list	timer, dtimer;
 	struct sock		*sk;		/* Backlink to socket */
+	atomic_t		refcount;
 } ax25_cb;
 
 #define ax25_sk(__sk) ((ax25_cb *)(__sk)->sk_protinfo)
 
+#define ax25_for_each(__ax25, node, list) \
+	hlist_for_each_entry(__ax25, node, list, ax25_node)
+
+#define ax25_cb_hold(__ax25) \
+	atomic_inc(&((__ax25)->refcount))
+
+static __inline__ void ax25_cb_put(ax25_cb *ax25)
+{
+	if (atomic_dec_and_test(&ax25->refcount)) {
+		if (ax25->digipeat)
+			kfree(ax25->digipeat);
+		kfree(ax25);
+	}
+}
+
 /* af_ax25.c */
-extern ax25_cb *ax25_list;
+extern struct hlist_head ax25_list;
 extern spinlock_t ax25_list_lock;
-extern void ax25_free_cb(ax25_cb *);
-extern void ax25_insert_socket(ax25_cb *);
+extern void ax25_cb_add(ax25_cb *);
 struct sock *ax25_find_listener(ax25_address *, int, struct net_device *, int);
 struct sock *ax25_get_socket(ax25_address *, ax25_address *, int);
 extern ax25_cb *ax25_find_cb(ax25_address *, ax25_address *, ax25_digi *, struct net_device *);

net/ax25/ax25_ds_in.c

@@ -65,6 +65,7 @@ static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int framet
 		ax25->state   = AX25_STATE_3;
 		ax25->n2count = 0;
 		if (ax25->sk != NULL) {
+			bh_lock_sock(ax25->sk);
 			ax25->sk->sk_state = TCP_ESTABLISHED;
 			/*
 			 * For WAIT_SABM connections we will produce an accept
@@ -72,6 +73,7 @@ static int ax25_ds_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int framet
 			 */
 			if (!sock_flag(ax25->sk, SOCK_DEAD))
 				ax25->sk->sk_state_change(ax25->sk);
+			bh_unlock_sock(ax25->sk);
 		}
 		ax25_dama_on(ax25);
 

net/ax25/ax25_ds_subr.c

@@ -40,6 +40,7 @@ void ax25_ds_nr_error_recovery(ax25_cb *ax25)
 void ax25_ds_enquiry_response(ax25_cb *ax25)
 {
 	ax25_cb *ax25o;
+	struct hlist_node *node;
 
 	/* Please note that neither DK4EGs nor DG2FEFs
 	 * DAMA spec mention the following behaviour as seen
@@ -80,7 +81,7 @@ void ax25_ds_enquiry_response(ax25_cb *ax25)
 	ax25_ds_set_timer(ax25->ax25_dev);
 
 	spin_lock_bh(&ax25_list_lock);
-	for (ax25o = ax25_list; ax25o != NULL; ax25o = ax25o->next) {
+	ax25_for_each(ax25o, node, &ax25_list) {
 		if (ax25o == ax25)
 			continue;
 
@@ -160,9 +161,10 @@ static int ax25_check_dama_slave(ax25_dev *ax25_dev)
 {
 	ax25_cb *ax25;
 	int res = 0;
+	struct hlist_node *node;
 
 	spin_lock_bh(&ax25_list_lock);
-	for (ax25 = ax25_list; ax25 != NULL ; ax25 = ax25->next)
+	ax25_for_each(ax25, node, &ax25_list)
 		if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) {
 			res = 1;
 			break;

net/ax25/ax25_ds_timer.c

@@ -74,6 +74,7 @@ static void ax25_ds_timeout(unsigned long arg)
 {
 	ax25_dev *ax25_dev = (struct ax25_dev *) arg;
 	ax25_cb *ax25;
+	struct hlist_node *node;
 
 	if (ax25_dev == NULL || !ax25_dev->dama.slave)
 		return;			/* Yikes! */
@@ -84,7 +85,7 @@ static void ax25_ds_timeout(unsigned long arg)
 	}
 
 	spin_lock_bh(&ax25_list_lock);
-	for (ax25=ax25_list; ax25 != NULL; ax25 = ax25->next) {
+	ax25_for_each(ax25, node, &ax25_list) {
 		if (ax25->ax25_dev != ax25_dev || !(ax25->condition & AX25_COND_DAMA_MODE))
 			continue;
 
@@ -98,14 +99,25 @@ static void ax25_ds_timeout(unsigned long arg)
 
 void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 {
+	struct sock *sk=ax25->sk;
+
+	if (sk)
+		bh_lock_sock(sk);
+
 	switch (ax25->state) {
 
 	case AX25_STATE_0:
 		/* Magic here: If we listen() and a new link dies before it
 		   is accepted() it isn't 'dead' so doesn't get removed. */
-		if (!ax25->sk || sock_flag(ax25->sk, SOCK_DESTROY) ||
-		    (ax25->sk->sk_state == TCP_LISTEN &&
-		     sock_flag(ax25->sk, SOCK_DEAD))) {
+		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
+		    (sk->sk_state == TCP_LISTEN &&
+		     sock_flag(sk, SOCK_DEAD))) {
+			if (sk) {
+				sock_hold(sk);
+				ax25_destroy_socket(ax25);
+				sock_put(sk);
+				bh_unlock_sock(sk);
+			} else
 				ax25_destroy_socket(ax25);
 			return;
 		}
@@ -115,9 +127,9 @@ void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 		/*
 		 * Check the state of the receive buffer.
 		 */
-		if (ax25->sk != NULL) {
-			if (atomic_read(&ax25->sk->sk_rmem_alloc) <
-			    (ax25->sk->sk_rcvbuf / 2) &&
+		if (sk != NULL) {
+			if (atomic_read(&sk->sk_rmem_alloc) <
+			    (sk->sk_rcvbuf / 2) &&
 			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 				ax25->condition &= ~AX25_COND_ACK_PENDING;
@@ -127,6 +139,9 @@ void ax25_ds_heartbeat_expiry(ax25_cb *ax25)
 		break;
 	}
 
+	if (sk)
+		bh_unlock_sock(sk);
+
 	ax25_start_heartbeat(ax25);
 }
 
@@ -157,6 +172,7 @@ void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 	ax25_stop_t3timer(ax25);
 
 	if (ax25->sk != NULL) {
+		bh_lock_sock(ax25->sk);
 		ax25->sk->sk_state     = TCP_CLOSE;
 		ax25->sk->sk_err       = 0;
 		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
@@ -164,6 +180,7 @@ void ax25_ds_idletimer_expiry(ax25_cb *ax25)
 			ax25->sk->sk_state_change(ax25->sk);
 			sock_set_flag(ax25->sk, SOCK_DEAD);
 		}
+		bh_lock_sock(ax25->sk);
 	}
 }
 

net/ax25/ax25_in.c

@@ -147,6 +147,7 @@ int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
 	}
 
 	if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
+		bh_lock_sock(ax25->sk);
 		if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) ||
 		    ax25->pidincl) {
 			if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
@@ -154,6 +155,7 @@ int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
 			else
 				ax25->condition |= AX25_COND_OWN_RX_BUSY;
 		}
+		bh_unlock_sock(ax25->sk);
 	}
 
 	return queued;
@@ -329,6 +331,7 @@ static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
 		if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
 			kfree_skb(skb);
 
+		ax25_cb_put(ax25);
 		return 0;
 	}
 
@@ -357,11 +360,14 @@ static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
 		sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
 
 	if (sk != NULL) {
+		bh_lock_sock(sk);
 		if (sk->sk_ack_backlog == sk->sk_max_ack_backlog ||
 		    (make = ax25_make_new(sk, ax25_dev)) == NULL) {
 			if (mine)
 				ax25_return_dm(dev, &src, &dest, &dp);
 			kfree_skb(skb);
+			bh_unlock_sock(sk);
+			sock_put(sk);
 
 			return 0;
 		}
@@ -374,6 +380,8 @@ static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
 		make->sk_pair  = sk;
 
 		sk->sk_ack_backlog++;
+		bh_unlock_sock(sk);
+		sock_put(sk);
 	} else {
 		if (!mine) {
 			kfree_skb(skb);
@@ -429,7 +437,7 @@ static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
 
 	ax25->state = AX25_STATE_3;
 
-	ax25_insert_socket(ax25);
+	ax25_cb_add(ax25);
 
 	ax25_start_heartbeat(ax25);
 	ax25_start_t3timer(ax25);

net/ax25/ax25_ip.c

@@ -107,6 +107,7 @@ int ax25_rebuild_header(struct sk_buff *skb)
 	ax25_address *src, *dst;
 	ax25_dev *ax25_dev;
 	ax25_route _route, *route = &_route;
+	ax25_cb *ax25;
 
 	dst = (ax25_address *)(bp + 1);
 	src = (ax25_address *)(bp + 8);
@@ -167,9 +168,14 @@ int ax25_rebuild_header(struct sk_buff *skb)
 			skb_pull(ourskb, AX25_HEADER_LEN - 1);	/* Keep PID */
 			ourskb->nh.raw = ourskb->data;
 
-			ax25_send_frame(ourskb, ax25_dev->values[AX25_VALUES_PACLEN], &src_c,
-&dst_c, route->digipeat, dev);
-
+			ax25=ax25_send_frame(
+			    ourskb, 
+			    ax25_dev->values[AX25_VALUES_PACLEN], 
+			    &src_c,
+			    &dst_c, route->digipeat, dev);
+			if (ax25) {
+				ax25_cb_put(ax25);
+			}
 			goto put;
 		}
 	}

net/ax25/ax25_out.c

@@ -71,7 +71,7 @@ ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax2
 
 	if (digi != NULL) {
 		if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
-			ax25_free_cb(ax25);
+			ax25_cb_put(ax25);
 			return NULL;
 		}
 		memcpy(ax25->digipeat, digi, sizeof(ax25_digi));
@@ -93,7 +93,7 @@ ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax2
 #endif
 	}
 
-	ax25_insert_socket(ax25);
+	ax25_cb_add(ax25);
 
 	ax25->state = AX25_STATE_1;
 

net/ax25/ax25_route.c

@@ -162,6 +162,7 @@ static void ax25_rt_destroy(ax25_route *ax25_rt)
 		if (ax25_rt->digipeat != NULL)
 			kfree(ax25_rt->digipeat);
 		kfree(ax25_rt);
+		return;
 	}
 
 	/*
@@ -434,8 +435,11 @@ int ax25_rt_autobind(ax25_cb *ax25, ax25_address *addr)
 		ax25_adjust_path(addr, ax25->digipeat);
 	}
 
-	if (ax25->sk != NULL)
+	if (ax25->sk != NULL) {
+		bh_lock_sock(ax25->sk);
 		ax25->sk->sk_zapped = 0;
+		bh_unlock_sock(ax25->sk);
+	}
 
 put:
 	ax25_put_route(ax25_rt);

net/ax25/ax25_std_in.c

@@ -73,10 +73,12 @@ static int ax25_std_state1_machine(ax25_cb *ax25, struct sk_buff *skb, int frame
 			ax25->state   = AX25_STATE_3;
 			ax25->n2count = 0;
 			if (ax25->sk != NULL) {
+				bh_lock_sock(ax25->sk);
 				ax25->sk->sk_state = TCP_ESTABLISHED;
 				/* For WAIT_SABM connections we will produce an accept ready socket here */
 				if (!sock_flag(ax25->sk, SOCK_DEAD))
 					ax25->sk->sk_state_change(ax25->sk);
+				bh_unlock_sock(ax25->sk);
 			}
 		}
 		break;

net/ax25/ax25_std_timer.c

@@ -33,13 +33,24 @@
 
 void ax25_std_heartbeat_expiry(ax25_cb *ax25)
 {
+	struct sock *sk=ax25->sk;
+	
+	if (sk)
+		bh_lock_sock(sk);
+
 	switch (ax25->state) {
 	case AX25_STATE_0:
 		/* Magic here: If we listen() and a new link dies before it
 		   is accepted() it isn't 'dead' so doesn't get removed. */
-		if (!ax25->sk || sock_flag(ax25->sk, SOCK_DESTROY) ||
-		    (ax25->sk->sk_state == TCP_LISTEN &&
-		     sock_flag(ax25->sk, SOCK_DEAD))) {
+		if (!sk || sock_flag(sk, SOCK_DESTROY) ||
+		    (sk->sk_state == TCP_LISTEN &&
+		     sock_flag(sk, SOCK_DEAD))) {
+			if (sk) {
+				sock_hold(sk);
+				ax25_destroy_socket(ax25);
+				bh_unlock_sock(sk);
+				sock_put(sk);
+			} else
 				ax25_destroy_socket(ax25);
 			return;
 		}
@@ -50,9 +61,9 @@ void ax25_std_heartbeat_expiry(ax25_cb *ax25)
 		/*
 		 * Check the state of the receive buffer.
 		 */
-		if (ax25->sk != NULL) {
-			if (atomic_read(&ax25->sk->sk_rmem_alloc) <
-			    (ax25->sk->sk_rcvbuf / 2) &&
+		if (sk != NULL) {
+			if (atomic_read(&sk->sk_rmem_alloc) <
+			    (sk->sk_rcvbuf / 2) &&
 			    (ax25->condition & AX25_COND_OWN_RX_BUSY)) {
 				ax25->condition &= ~AX25_COND_OWN_RX_BUSY;
 				ax25->condition &= ~AX25_COND_ACK_PENDING;
@@ -62,6 +73,9 @@ void ax25_std_heartbeat_expiry(ax25_cb *ax25)
 		}
 	}
 
+	if (sk)
+		bh_unlock_sock(sk);
+
 	ax25_start_heartbeat(ax25);
 }
 
@@ -94,6 +108,7 @@ void ax25_std_idletimer_expiry(ax25_cb *ax25)
 	ax25_stop_t3timer(ax25);
 
 	if (ax25->sk != NULL) {
+		bh_lock_sock(ax25->sk);
 		ax25->sk->sk_state     = TCP_CLOSE;
 		ax25->sk->sk_err       = 0;
 		ax25->sk->sk_shutdown |= SEND_SHUTDOWN;
@@ -101,6 +116,7 @@ void ax25_std_idletimer_expiry(ax25_cb *ax25)
 			ax25->sk->sk_state_change(ax25->sk);
 			sock_set_flag(ax25->sk, SOCK_DEAD);
 		}
+		bh_unlock_sock(ax25->sk);
 	}
 }
 

net/ax25/ax25_timer.c

@@ -141,13 +141,10 @@ static void ax25_heartbeat_expiry(unsigned long param)
 {
 	int proto = AX25_PROTO_STD_SIMPLEX;
 	ax25_cb *ax25 = (ax25_cb *)param;
-	struct sock *sk = ax25->sk;
 
 	if (ax25->ax25_dev)
 		proto = ax25->ax25_dev->values[AX25_VALUES_PROTOCOL];
 
-	bh_lock_sock(sk);
-
 	switch (proto) {
 	case AX25_PROTO_STD_SIMPLEX:
 	case AX25_PROTO_STD_DUPLEX:
@@ -163,15 +160,12 @@ static void ax25_heartbeat_expiry(unsigned long param)
 		break;
 #endif
 	}
-	bh_unlock_sock(sk);
 }
 
 static void ax25_t1timer_expiry(unsigned long param)
 {
 	ax25_cb *ax25 = (ax25_cb *)param;
-	struct sock *sk = ax25->sk;
 
-	bh_lock_sock(sk);
 	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
 	case AX25_PROTO_STD_SIMPLEX:
 	case AX25_PROTO_STD_DUPLEX:
@@ -185,15 +179,12 @@ static void ax25_t1timer_expiry(unsigned long param)
 		break;
 #endif
 	}
-	bh_unlock_sock(sk);
 }
 
 static void ax25_t2timer_expiry(unsigned long param)
 {
 	ax25_cb *ax25 = (ax25_cb *)param;
-	struct sock *sk = ax25->sk;
 
-	bh_lock_sock(sk);
 	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
 	case AX25_PROTO_STD_SIMPLEX:
 	case AX25_PROTO_STD_DUPLEX:
@@ -207,15 +198,12 @@ static void ax25_t2timer_expiry(unsigned long param)
 		break;
 #endif
 	}
-	bh_unlock_sock(sk);
 }
 
 static void ax25_t3timer_expiry(unsigned long param)
 {
 	ax25_cb *ax25 = (ax25_cb *)param;
-	struct sock *sk = ax25->sk;
 
-	bh_lock_sock(sk);
 	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
 	case AX25_PROTO_STD_SIMPLEX:
 	case AX25_PROTO_STD_DUPLEX:
@@ -231,15 +219,12 @@ static void ax25_t3timer_expiry(unsigned long param)
 		break;
 #endif
 	}
-	bh_unlock_sock(sk);
 }
 
 static void ax25_idletimer_expiry(unsigned long param)
 {
 	ax25_cb *ax25 = (ax25_cb *)param;
-	struct sock *sk = ax25->sk;
 
-	bh_lock_sock(sk);
 	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
 	case AX25_PROTO_STD_SIMPLEX:
 	case AX25_PROTO_STD_DUPLEX:
@@ -255,5 +240,4 @@ static void ax25_idletimer_expiry(unsigned long param)
 		break;
 #endif
 	}
-	bh_unlock_sock(sk);
 }

net/ax25/sysctl_net_ax25.c

@@ -204,8 +204,10 @@ void ax25_register_sysctl(void)
 	for (ax25_table_size = sizeof(ctl_table), ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
 		ax25_table_size += sizeof(ctl_table);
 
-	if ((ax25_table = kmalloc(ax25_table_size, GFP_ATOMIC)) == NULL)
+	if ((ax25_table = kmalloc(ax25_table_size, GFP_ATOMIC)) == NULL) {
+		spin_unlock_bh(&ax25_dev_lock);
 		return;
+	}
 
 	memset(ax25_table, 0x00, ax25_table_size);