1 files changed, 399 insertions, 0 deletions
diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c
new file mode 100644
index 000000000..1bdd3df08
--- /dev/null
+++ b/drivers/net/wan/hdlc.c
@@ -0,0 +1,399 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Generic HDLC support routines for Linux
+ *
+ * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
+ *
+ * Currently supported:
+ *	* raw IP-in-HDLC
+ *	* Cisco HDLC
+ *	* Frame Relay with ANSI or CCITT LMI (both user and network side)
+ *	* PPP
+ *	* X.25
+ *
+ * Use sethdlc utility to set line parameters, protocol and PVCs
+ *
+ * How does it work:
+ * - proto->open(), close(), start(), stop() calls are serialized.
+ *   The order is: open, [ start, stop ... ] close ...
+ * - proto->start() and stop() are called with spin_lock_irq held.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/hdlc.h>
+#include <linux/if_arp.h>
+#include <linux/inetdevice.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/pkt_sched.h>
+#include <linux/poll.h>
+#include <linux/rtnetlink.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/net_namespace.h>
+
+
+static const char* version = "HDLC support module revision 1.22";
+
+#undef DEBUG_LINK
+
+static struct hdlc_proto *first_proto;
+
+static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
+		    struct packet_type *p, struct net_device *orig_dev)
+{
+	struct hdlc_device *hdlc;
+
+	/* First make sure "dev" is an HDLC device */
+	if (!(dev->priv_flags & IFF_WAN_HDLC)) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	hdlc = dev_to_hdlc(dev);
+
+	if (!net_eq(dev_net(dev), &init_net)) {
+		kfree_skb(skb);
+		return 0;
+	}
+
+	BUG_ON(!hdlc->proto->netif_rx);
+	return hdlc->proto->netif_rx(skb);
+}
+
+netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+
+	if (hdlc->proto->xmit)
+		return hdlc->proto->xmit(skb, dev);
+
+	return hdlc->xmit(skb, dev); /* call hardware driver directly */
+}
+
+static inline void hdlc_proto_start(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	if (hdlc->proto->start)
+		hdlc->proto->start(dev);
+}
+
+
+
+static inline void hdlc_proto_stop(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	if (hdlc->proto->stop)
+		hdlc->proto->stop(dev);
+}
+
+
+
+static int hdlc_device_event(struct notifier_block *this, unsigned long event,
+			     void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	hdlc_device *hdlc;
+	unsigned long flags;
+	int on;
+
+	if (!net_eq(dev_net(dev), &init_net))
+		return NOTIFY_DONE;
+
+	if (!(dev->priv_flags & IFF_WAN_HDLC))
+		return NOTIFY_DONE; /* not an HDLC device */
+
+	if (event != NETDEV_CHANGE)
+		return NOTIFY_DONE; /* Only interested in carrier changes */
+
+	on = netif_carrier_ok(dev);
+
+#ifdef DEBUG_LINK
+	printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
+	       dev->name, on);
+#endif
+
+	hdlc = dev_to_hdlc(dev);
+	spin_lock_irqsave(&hdlc->state_lock, flags);
+
+	if (hdlc->carrier == on)
+		goto carrier_exit; /* no change in DCD line level */
+
+	hdlc->carrier = on;
+
+	if (!hdlc->open)
+		goto carrier_exit;
+
+	if (hdlc->carrier) {
+		netdev_info(dev, "Carrier detected\n");
+		hdlc_proto_start(dev);
+	} else {
+		netdev_info(dev, "Carrier lost\n");
+		hdlc_proto_stop(dev);
+	}
+
+carrier_exit:
+	spin_unlock_irqrestore(&hdlc->state_lock, flags);
+	return NOTIFY_DONE;
+}
+
+
+
+/* Must be called by hardware driver when HDLC device is being opened */
+int hdlc_open(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+#ifdef DEBUG_LINK
+	printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
+	       hdlc->carrier, hdlc->open);
+#endif
+
+	if (hdlc->proto == NULL)
+		return -ENOSYS;	/* no protocol attached */
+
+	if (hdlc->proto->open) {
+		int result = hdlc->proto->open(dev);
+		if (result)
+			return result;
+	}
+
+	spin_lock_irq(&hdlc->state_lock);
+
+	if (hdlc->carrier) {
+		netdev_info(dev, "Carrier detected\n");
+		hdlc_proto_start(dev);
+	} else
+		netdev_info(dev, "No carrier\n");
+
+	hdlc->open = 1;
+
+	spin_unlock_irq(&hdlc->state_lock);
+	return 0;
+}
+
+
+
+/* Must be called by hardware driver when HDLC device is being closed */
+void hdlc_close(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+#ifdef DEBUG_LINK
+	printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
+	       hdlc->carrier, hdlc->open);
+#endif
+
+	spin_lock_irq(&hdlc->state_lock);
+
+	hdlc->open = 0;
+	if (hdlc->carrier)
+		hdlc_proto_stop(dev);
+
+	spin_unlock_irq(&hdlc->state_lock);
+
+	if (hdlc->proto->close)
+		hdlc->proto->close(dev);
+}
+
+
+
+int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	struct hdlc_proto *proto = first_proto;
+	int result;
+
+	if (cmd != SIOCWANDEV)
+		return -EINVAL;
+
+	if (dev_to_hdlc(dev)->proto) {
+		result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
+		if (result != -EINVAL)
+			return result;
+	}
+
+	/* Not handled by currently attached protocol (if any) */
+
+	while (proto) {
+		if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
+			return result;
+		proto = proto->next;
+	}
+	return -EINVAL;
+}
+
+static const struct header_ops hdlc_null_ops;
+
+static void hdlc_setup_dev(struct net_device *dev)
+{
+	/* Re-init all variables changed by HDLC protocol drivers,
+	 * including ether_setup() called from hdlc_raw_eth.c.
+	 */
+	dev->flags		 = IFF_POINTOPOINT | IFF_NOARP;
+	dev->priv_flags		 = IFF_WAN_HDLC;
+	dev->mtu		 = HDLC_MAX_MTU;
+	dev->min_mtu		 = 68;
+	dev->max_mtu		 = HDLC_MAX_MTU;
+	dev->type		 = ARPHRD_RAWHDLC;
+	dev->hard_header_len	 = 0;
+	dev->needed_headroom	 = 0;
+	dev->addr_len		 = 0;
+	dev->header_ops		 = &hdlc_null_ops;
+}
+
+static void hdlc_setup(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+
+	hdlc_setup_dev(dev);
+	hdlc->carrier = 1;
+	hdlc->open = 0;
+	spin_lock_init(&hdlc->state_lock);
+}
+
+struct net_device *alloc_hdlcdev(void *priv)
+{
+	struct net_device *dev;
+	dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
+			   NET_NAME_UNKNOWN, hdlc_setup);
+	if (dev)
+		dev_to_hdlc(dev)->priv = priv;
+	return dev;
+}
+
+void unregister_hdlc_device(struct net_device *dev)
+{
+	rtnl_lock();
+	detach_hdlc_protocol(dev);
+	unregister_netdevice(dev);
+	rtnl_unlock();
+}
+
+
+
+int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
+			 size_t size)
+{
+	int err;
+
+	err = detach_hdlc_protocol(dev);
+	if (err)
+		return err;
+
+	if (!try_module_get(proto->module))
+		return -ENOSYS;
+
+	if (size) {
+		dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
+		if (dev_to_hdlc(dev)->state == NULL) {
+			module_put(proto->module);
+			return -ENOBUFS;
+		}
+	}
+	dev_to_hdlc(dev)->proto = proto;
+
+	return 0;
+}
+
+
+int detach_hdlc_protocol(struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	int err;
+
+	if (hdlc->proto) {
+		err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
+		err = notifier_to_errno(err);
+		if (err) {
+			netdev_err(dev, "Refused to change device type\n");
+			return err;
+		}
+
+		if (hdlc->proto->detach)
+			hdlc->proto->detach(dev);
+		module_put(hdlc->proto->module);
+		hdlc->proto = NULL;
+	}
+	kfree(hdlc->state);
+	hdlc->state = NULL;
+	hdlc_setup_dev(dev);
+
+	return 0;
+}
+
+
+void register_hdlc_protocol(struct hdlc_proto *proto)
+{
+	rtnl_lock();
+	proto->next = first_proto;
+	first_proto = proto;
+	rtnl_unlock();
+}
+
+
+void unregister_hdlc_protocol(struct hdlc_proto *proto)
+{
+	struct hdlc_proto **p;
+
+	rtnl_lock();
+	p = &first_proto;
+	while (*p != proto) {
+		BUG_ON(!*p);
+		p = &((*p)->next);
+	}
+	*p = proto->next;
+	rtnl_unlock();
+}
+
+
+
+MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
+MODULE_DESCRIPTION("HDLC support module");
+MODULE_LICENSE("GPL v2");
+
+EXPORT_SYMBOL(hdlc_start_xmit);
+EXPORT_SYMBOL(hdlc_open);
+EXPORT_SYMBOL(hdlc_close);
+EXPORT_SYMBOL(hdlc_ioctl);
+EXPORT_SYMBOL(alloc_hdlcdev);
+EXPORT_SYMBOL(unregister_hdlc_device);
+EXPORT_SYMBOL(register_hdlc_protocol);
+EXPORT_SYMBOL(unregister_hdlc_protocol);
+EXPORT_SYMBOL(attach_hdlc_protocol);
+EXPORT_SYMBOL(detach_hdlc_protocol);
+
+static struct packet_type hdlc_packet_type __read_mostly = {
+	.type = cpu_to_be16(ETH_P_HDLC),
+	.func = hdlc_rcv,
+};
+
+
+static struct notifier_block hdlc_notifier = {
+	.notifier_call = hdlc_device_event,
+};
+
+
+static int __init hdlc_module_init(void)
+{
+	int result;
+
+	pr_info("%s\n", version);
+	if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
+		return result;
+	dev_add_pack(&hdlc_packet_type);
+	return 0;
+}
+
+
+
+static void __exit hdlc_module_exit(void)
+{
+	dev_remove_pack(&hdlc_packet_type);
+	unregister_netdevice_notifier(&hdlc_notifier);
+}
+
+
+module_init(hdlc_module_init);
+module_exit(hdlc_module_exit);