1 files changed, 107 insertions, 43 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index c96fa0f33db3..27706f6ace34 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
 /*
  * bcm.c - Broadcast Manager to filter/send (cyclic) CAN content
  *
@@ -81,13 +81,13 @@
 		     (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
 		     (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
 
-#define CAN_BCM_VERSION "20170425"
-
 MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
 MODULE_ALIAS("can-proto-2");
 
+#define BCM_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_ifindex)
+
 /*
  * easy access to the first 64 bit of can(fd)_frame payload. cp->data is
  * 64 bit aligned so the offset has to be multiples of 8 which is ensured
@@ -100,6 +100,7 @@ static inline u64 get_u64(const struct canfd_frame *cp, int offset)
 
 struct bcm_op {
 	struct list_head list;
+	struct rcu_head rcu;
 	int ifindex;
 	canid_t can_id;
 	u32 flags;
@@ -125,7 +126,7 @@ struct bcm_sock {
 	struct sock sk;
 	int bound;
 	int ifindex;
-	struct notifier_block notifier;
+	struct list_head notifier;
 	struct list_head rx_ops;
 	struct list_head tx_ops;
 	unsigned long dropped_usr_msgs;
@@ -133,6 +134,10 @@ struct bcm_sock {
 	char procname [32]; /* inode number in decimal with \0 */
 };
 
+static LIST_HEAD(bcm_notifier_list);
+static DEFINE_SPINLOCK(bcm_notifier_lock);
+static struct bcm_sock *bcm_busy_notifier;
+
 static inline struct bcm_sock *bcm_sk(const struct sock *sk)
 {
 	return (struct bcm_sock *)sk;
@@ -189,7 +194,7 @@ static int bcm_proc_show(struct seq_file *m, void *v)
 {
 	char ifname[IFNAMSIZ];
 	struct net *net = m->private;
-	struct sock *sk = (struct sock *)PDE_DATA(m->file->f_inode);
+	struct sock *sk = (struct sock *)pde_data(m->file->f_inode);
 	struct bcm_sock *bo = bcm_sk(sk);
 	struct bcm_op *op;
 
@@ -269,6 +274,7 @@ static void bcm_can_tx(struct bcm_op *op)
 	struct sk_buff *skb;
 	struct net_device *dev;
 	struct canfd_frame *cf = op->frames + op->cfsiz * op->currframe;
+	int err;
 
 	/* no target device? => exit */
 	if (!op->ifindex)
@@ -293,11 +299,11 @@ static void bcm_can_tx(struct bcm_op *op)
 	/* send with loopback */
 	skb->dev = dev;
 	can_skb_set_owner(skb, op->sk);
-	can_send(skb, 1);
+	err = can_send(skb, 1);
+	if (!err)
+		op->frames_abs++;
 
-	/* update statistics */
 	op->currframe++;
-	op->frames_abs++;
 
 	/* reached last frame? */
 	if (op->currframe >= op->nframes)
@@ -402,6 +408,7 @@ static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
 		if (!op->count && (op->flags & TX_COUNTEVT)) {
 
 			/* create notification to user */
+			memset(&msg_head, 0, sizeof(msg_head));
 			msg_head.opcode  = TX_EXPIRED;
 			msg_head.flags   = op->flags;
 			msg_head.count   = op->count;
@@ -439,6 +446,7 @@ static void bcm_rx_changed(struct bcm_op *op, struct canfd_frame *data)
 	/* this element is not throttled anymore */
 	data->flags &= (BCM_CAN_FLAGS_MASK|RX_RECV);
 
+	memset(&head, 0, sizeof(head));
 	head.opcode  = RX_CHANGED;
 	head.flags   = op->flags;
 	head.count   = op->count;
@@ -560,6 +568,7 @@ static enum hrtimer_restart bcm_rx_timeout_handler(struct hrtimer *hrtimer)
 	}
 
 	/* create notification to user */
+	memset(&msg_head, 0, sizeof(msg_head));
 	msg_head.opcode  = RX_TIMEOUT;
 	msg_head.flags   = op->flags;
 	msg_head.count   = op->count;
@@ -618,7 +627,7 @@ static enum hrtimer_restart bcm_rx_thr_handler(struct hrtimer *hrtimer)
 	struct bcm_op *op = container_of(hrtimer, struct bcm_op, thrtimer);
 
 	if (bcm_rx_thr_flush(op)) {
-		hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
+		hrtimer_forward_now(hrtimer, op->kt_ival2);
 		return HRTIMER_RESTART;
 	} else {
 		/* rearm throttle handling */
@@ -640,8 +649,13 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data)
 		return;
 
 	/* make sure to handle the correct frame type (CAN / CAN FD) */
-	if (skb->len != op->cfsiz)
-		return;
+	if (op->flags & CAN_FD_FRAME) {
+		if (!can_is_canfd_skb(skb))
+			return;
+	} else {
+		if (!can_is_can_skb(skb))
+			return;
+	}
 
 	/* disable timeout */
 	hrtimer_cancel(&op->timer);
@@ -711,10 +725,9 @@ static struct bcm_op *bcm_find_op(struct list_head *ops,
 	return NULL;
 }
 
-static void bcm_remove_op(struct bcm_op *op)
+static void bcm_free_op_rcu(struct rcu_head *rcu_head)
 {
-	hrtimer_cancel(&op->timer);
-	hrtimer_cancel(&op->thrtimer);
+	struct bcm_op *op = container_of(rcu_head, struct bcm_op, rcu);
 
 	if ((op->frames) && (op->frames != &op->sframe))
 		kfree(op->frames);
@@ -725,6 +738,14 @@ static void bcm_remove_op(struct bcm_op *op)
 	kfree(op);
 }
 
+static void bcm_remove_op(struct bcm_op *op)
+{
+	hrtimer_cancel(&op->timer);
+	hrtimer_cancel(&op->thrtimer);
+
+	call_rcu(&op->rcu, bcm_free_op_rcu);
+}
+
 static void bcm_rx_unreg(struct net_device *dev, struct bcm_op *op)
 {
 	if (op->rx_reg_dev == dev) {
@@ -750,6 +771,9 @@ static int bcm_delete_rx_op(struct list_head *ops, struct bcm_msg_head *mh,
 		if ((op->can_id == mh->can_id) && (op->ifindex == ifindex) &&
 		    (op->flags & CAN_FD_FRAME) == (mh->flags & CAN_FD_FRAME)) {
 
+			/* disable automatic timer on frame reception */
+			op->flags |= RX_NO_AUTOTIMER;
+
 			/*
 			 * Don't care if we're bound or not (due to netdev
 			 * problems) can_rx_unregister() is always a save
@@ -1294,7 +1318,7 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 		/* no bound device as default => check msg_name */
 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
 
-		if (msg->msg_namelen < CAN_REQUIRED_SIZE(*addr, can_ifindex))
+		if (msg->msg_namelen < BCM_MIN_NAMELEN)
 			return -EINVAL;
 
 		if (addr->can_family != AF_CAN)
@@ -1378,20 +1402,15 @@ static int bcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 /*
  * notification handler for netdevice status changes
  */
-static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
-			void *ptr)
+static void bcm_notify(struct bcm_sock *bo, unsigned long msg,
+		       struct net_device *dev)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct bcm_sock *bo = container_of(nb, struct bcm_sock, notifier);
 	struct sock *sk = &bo->sk;
 	struct bcm_op *op;
 	int notify_enodev = 0;
 
 	if (!net_eq(dev_net(dev), sock_net(sk)))
-		return NOTIFY_DONE;
-
-	if (dev->type != ARPHRD_CAN)
-		return NOTIFY_DONE;
+		return;
 
 	switch (msg) {
 
@@ -1415,7 +1434,7 @@ static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
 		if (notify_enodev) {
 			sk->sk_err = ENODEV;
 			if (!sock_flag(sk, SOCK_DEAD))
-				sk->sk_error_report(sk);
+				sk_error_report(sk);
 		}
 		break;
 
@@ -1423,10 +1442,31 @@ static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
 		if (bo->bound && bo->ifindex == dev->ifindex) {
 			sk->sk_err = ENETDOWN;
 			if (!sock_flag(sk, SOCK_DEAD))
-				sk->sk_error_report(sk);
+				sk_error_report(sk);
 		}
 	}
+}
+
+static int bcm_notifier(struct notifier_block *nb, unsigned long msg,
+			void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 
+	if (dev->type != ARPHRD_CAN)
+		return NOTIFY_DONE;
+	if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+		return NOTIFY_DONE;
+	if (unlikely(bcm_busy_notifier)) /* Check for reentrant bug. */
+		return NOTIFY_DONE;
+
+	spin_lock(&bcm_notifier_lock);
+	list_for_each_entry(bcm_busy_notifier, &bcm_notifier_list, notifier) {
+		spin_unlock(&bcm_notifier_lock);
+		bcm_notify(bcm_busy_notifier, msg, dev);
+		spin_lock(&bcm_notifier_lock);
+	}
+	bcm_busy_notifier = NULL;
+	spin_unlock(&bcm_notifier_lock);
 	return NOTIFY_DONE;
 }
 
@@ -1446,9 +1486,9 @@ static int bcm_init(struct sock *sk)
 	INIT_LIST_HEAD(&bo->rx_ops);
 
 	/* set notifier */
-	bo->notifier.notifier_call = bcm_notifier;
-
-	register_netdevice_notifier(&bo->notifier);
+	spin_lock(&bcm_notifier_lock);
+	list_add_tail(&bo->notifier, &bcm_notifier_list);
+	spin_unlock(&bcm_notifier_lock);
 
 	return 0;
 }
@@ -1471,7 +1511,14 @@ static int bcm_release(struct socket *sock)
 
 	/* remove bcm_ops, timer, rx_unregister(), etc. */
 
-	unregister_netdevice_notifier(&bo->notifier);
+	spin_lock(&bcm_notifier_lock);
+	while (bcm_busy_notifier == bo) {
+		spin_unlock(&bcm_notifier_lock);
+		schedule_timeout_uninterruptible(1);
+		spin_lock(&bcm_notifier_lock);
+	}
+	list_del(&bo->notifier);
+	spin_unlock(&bcm_notifier_lock);
 
 	lock_sock(sk);
 
@@ -1503,9 +1550,13 @@ static int bcm_release(struct socket *sock)
 					  REGMASK(op->can_id),
 					  bcm_rx_handler, op);
 
-		bcm_remove_op(op);
 	}
 
+	synchronize_rcu();
+
+	list_for_each_entry_safe(op, next, &bo->rx_ops, list)
+		bcm_remove_op(op);
+
 #if IS_ENABLED(CONFIG_PROC_FS)
 	/* remove procfs entry */
 	if (net->can.bcmproc_dir && bo->bcm_proc_read)
@@ -1536,7 +1587,7 @@ static int bcm_connect(struct socket *sock, struct sockaddr *uaddr, int len,
 	struct net *net = sock_net(sk);
 	int ret = 0;
 
-	if (len < CAN_REQUIRED_SIZE(*addr, can_ifindex))
+	if (len < BCM_MIN_NAMELEN)
 		return -EINVAL;
 
 	lock_sock(sk);
@@ -1597,12 +1648,9 @@ static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 	struct sock *sk = sock->sk;
 	struct sk_buff *skb;
 	int error = 0;
-	int noblock;
 	int err;
 
-	noblock =  flags & MSG_DONTWAIT;
-	flags   &= ~MSG_DONTWAIT;
-	skb = skb_recv_datagram(sk, flags, noblock, &error);
+	skb = skb_recv_datagram(sk, flags, &error);
 	if (!skb)
 		return error;
 
@@ -1615,11 +1663,11 @@ static int bcm_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
 		return err;
 	}
 
-	sock_recv_ts_and_drops(msg, sk, skb);
+	sock_recv_cmsgs(msg, sk, skb);
 
 	if (msg->msg_name) {
-		__sockaddr_check_size(sizeof(struct sockaddr_can));
-		msg->msg_namelen = sizeof(struct sockaddr_can);
+		__sockaddr_check_size(BCM_MIN_NAMELEN);
+		msg->msg_namelen = BCM_MIN_NAMELEN;
 		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
 	}
 
@@ -1648,8 +1696,6 @@ static const struct proto_ops bcm_ops = {
 	.gettstamp     = sock_gettstamp,
 	.listen        = sock_no_listen,
 	.shutdown      = sock_no_shutdown,
-	.setsockopt    = sock_no_setsockopt,
-	.getsockopt    = sock_no_getsockopt,
 	.sendmsg       = bcm_sendmsg,
 	.recvmsg       = bcm_recvmsg,
 	.mmap          = sock_no_mmap,
@@ -1694,25 +1740,43 @@ static struct pernet_operations canbcm_pernet_ops __read_mostly = {
 	.exit = canbcm_pernet_exit,
 };
 
+static struct notifier_block canbcm_notifier = {
+	.notifier_call = bcm_notifier
+};
+
 static int __init bcm_module_init(void)
 {
 	int err;
 
-	pr_info("can: broadcast manager protocol (rev " CAN_BCM_VERSION " t)\n");
+	pr_info("can: broadcast manager protocol\n");
+
+	err = register_pernet_subsys(&canbcm_pernet_ops);
+	if (err)
+		return err;
+
+	err = register_netdevice_notifier(&canbcm_notifier);
+	if (err)
+		goto register_notifier_failed;
 
 	err = can_proto_register(&bcm_can_proto);
 	if (err < 0) {
 		printk(KERN_ERR "can: registration of bcm protocol failed\n");
-		return err;
+		goto register_proto_failed;
 	}
 
-	register_pernet_subsys(&canbcm_pernet_ops);
 	return 0;
+
+register_proto_failed:
+	unregister_netdevice_notifier(&canbcm_notifier);
+register_notifier_failed:
+	unregister_pernet_subsys(&canbcm_pernet_ops);
+	return err;
 }
 
 static void __exit bcm_module_exit(void)
 {
 	can_proto_unregister(&bcm_can_proto);
+	unregister_netdevice_notifier(&canbcm_notifier);
 	unregister_pernet_subsys(&canbcm_pernet_ops);
 }