v4.19.13 snapshot.
diff --git a/drivers/net/wan/dlci.c b/drivers/net/wan/dlci.c
new file mode 100644
index 0000000..a0d76f7
--- /dev/null
+++ b/drivers/net/wan/dlci.c
@@ -0,0 +1,546 @@
+/*
+ * DLCI		Implementation of Frame Relay protocol for Linux, according to
+ *		RFC 1490.  This generic device provides en/decapsulation for an
+ *		underlying hardware driver.  Routes & IPs are assigned to these
+ *		interfaces.  Requires 'dlcicfg' program to create usable 
+ *		interfaces, the initial one, 'dlci' is for IOCTL use only.
+ *
+ * Version:	@(#)dlci.c	0.35	4 Jan 1997
+ *
+ * Author:	Mike McLagan <mike.mclagan@linux.org>
+ *
+ * Changes:
+ *
+ *		0.15	Mike Mclagan	Packet freeing, bug in kmalloc call
+ *					DLCI_RET handling
+ *		0.20	Mike McLagan	More conservative on which packets
+ *					are returned for retry and which are
+ *					are dropped.  If DLCI_RET_DROP is
+ *					returned from the FRAD, the packet is
+ *				 	sent back to Linux for re-transmission
+ *		0.25	Mike McLagan	Converted to use SIOC IOCTL calls
+ *		0.30	Jim Freeman	Fixed to allow IPX traffic
+ *		0.35	Michael Elizabeth	Fixed incorrect memcpy_fromfs
+ *
+ *		This program 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/ioport.h>
+#include <linux/in.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/if_frad.h>
+#include <linux/bitops.h>
+
+#include <net/sock.h>
+
+#include <asm/io.h>
+#include <asm/dma.h>
+#include <linux/uaccess.h>
+
+static const char version[] = "DLCI driver v0.35, 4 Jan 1997, mike.mclagan@linux.org";
+
+static LIST_HEAD(dlci_devs);
+
+static void dlci_setup(struct net_device *);
+
+/* 
+ * these encapsulate the RFC 1490 requirements as well as 
+ * deal with packet transmission and reception, working with
+ * the upper network layers 
+ */
+
+static int dlci_header(struct sk_buff *skb, struct net_device *dev, 
+		       unsigned short type, const void *daddr,
+		       const void *saddr, unsigned len)
+{
+	struct frhdr		hdr;
+	unsigned int		hlen;
+	char			*dest;
+
+	hdr.control = FRAD_I_UI;
+	switch (type)
+	{
+		case ETH_P_IP:
+			hdr.IP_NLPID = FRAD_P_IP;
+			hlen = sizeof(hdr.control) + sizeof(hdr.IP_NLPID);
+			break;
+
+		/* feel free to add other types, if necessary */
+
+		default:
+			hdr.pad = FRAD_P_PADDING;
+			hdr.NLPID = FRAD_P_SNAP;
+			memset(hdr.OUI, 0, sizeof(hdr.OUI));
+			hdr.PID = htons(type);
+			hlen = sizeof(hdr);
+			break;
+	}
+
+	dest = skb_push(skb, hlen);
+	if (!dest)
+		return 0;
+
+	memcpy(dest, &hdr, hlen);
+
+	return hlen;
+}
+
+static void dlci_receive(struct sk_buff *skb, struct net_device *dev)
+{
+	struct frhdr		*hdr;
+	int					process, header;
+
+	if (!pskb_may_pull(skb, sizeof(*hdr))) {
+		netdev_notice(dev, "invalid data no header\n");
+		dev->stats.rx_errors++;
+		kfree_skb(skb);
+		return;
+	}
+
+	hdr = (struct frhdr *) skb->data;
+	process = 0;
+	header = 0;
+	skb->dev = dev;
+
+	if (hdr->control != FRAD_I_UI)
+	{
+		netdev_notice(dev, "Invalid header flag 0x%02X\n",
+			      hdr->control);
+		dev->stats.rx_errors++;
+	}
+	else
+		switch (hdr->IP_NLPID)
+		{
+			case FRAD_P_PADDING:
+				if (hdr->NLPID != FRAD_P_SNAP)
+				{
+					netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
+						      hdr->NLPID);
+					dev->stats.rx_errors++;
+					break;
+				}
+	 
+				if (hdr->OUI[0] + hdr->OUI[1] + hdr->OUI[2] != 0)
+				{
+					netdev_notice(dev, "Unsupported organizationally unique identifier 0x%02X-%02X-%02X\n",
+						      hdr->OUI[0],
+						      hdr->OUI[1],
+						      hdr->OUI[2]);
+					dev->stats.rx_errors++;
+					break;
+				}
+
+				/* at this point, it's an EtherType frame */
+				header = sizeof(struct frhdr);
+				/* Already in network order ! */
+				skb->protocol = hdr->PID;
+				process = 1;
+				break;
+
+			case FRAD_P_IP:
+				header = sizeof(hdr->control) + sizeof(hdr->IP_NLPID);
+				skb->protocol = htons(ETH_P_IP);
+				process = 1;
+				break;
+
+			case FRAD_P_SNAP:
+			case FRAD_P_Q933:
+			case FRAD_P_CLNP:
+				netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
+					      hdr->pad);
+				dev->stats.rx_errors++;
+				break;
+
+			default:
+				netdev_notice(dev, "Invalid pad byte 0x%02X\n",
+					      hdr->pad);
+				dev->stats.rx_errors++;
+				break;				
+		}
+
+	if (process)
+	{
+		/* we've set up the protocol, so discard the header */
+		skb_reset_mac_header(skb);
+		skb_pull(skb, header);
+		dev->stats.rx_bytes += skb->len;
+		netif_rx(skb);
+		dev->stats.rx_packets++;
+	}
+	else
+		dev_kfree_skb(skb);
+}
+
+static netdev_tx_t dlci_transmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dlci_local *dlp = netdev_priv(dev);
+
+	if (skb) {
+		struct netdev_queue *txq = skb_get_tx_queue(dev, skb);
+		netdev_start_xmit(skb, dlp->slave, txq, false);
+	}
+	return NETDEV_TX_OK;
+}
+
+static int dlci_config(struct net_device *dev, struct dlci_conf __user *conf, int get)
+{
+	struct dlci_conf	config;
+	struct dlci_local	*dlp;
+	struct frad_local	*flp;
+	int			err;
+
+	dlp = netdev_priv(dev);
+
+	flp = netdev_priv(dlp->slave);
+
+	if (!get)
+	{
+		if (copy_from_user(&config, conf, sizeof(struct dlci_conf)))
+			return -EFAULT;
+		if (config.flags & ~DLCI_VALID_FLAGS)
+			return -EINVAL;
+		memcpy(&dlp->config, &config, sizeof(struct dlci_conf));
+		dlp->configured = 1;
+	}
+
+	err = (*flp->dlci_conf)(dlp->slave, dev, get);
+	if (err)
+		return err;
+
+	if (get)
+	{
+		if (copy_to_user(conf, &dlp->config, sizeof(struct dlci_conf)))
+			return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int dlci_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	struct dlci_local *dlp;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	dlp = netdev_priv(dev);
+
+	switch (cmd)
+	{
+		case DLCI_GET_SLAVE:
+			if (!*(short *)(dev->dev_addr))
+				return -EINVAL;
+
+			strncpy(ifr->ifr_slave, dlp->slave->name, sizeof(ifr->ifr_slave));
+			break;
+
+		case DLCI_GET_CONF:
+		case DLCI_SET_CONF:
+			if (!*(short *)(dev->dev_addr))
+				return -EINVAL;
+
+			return dlci_config(dev, ifr->ifr_data, cmd == DLCI_GET_CONF);
+
+		default: 
+			return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int dlci_change_mtu(struct net_device *dev, int new_mtu)
+{
+	struct dlci_local *dlp = netdev_priv(dev);
+
+	return dev_set_mtu(dlp->slave, new_mtu);
+}
+
+static int dlci_open(struct net_device *dev)
+{
+	struct dlci_local	*dlp;
+	struct frad_local	*flp;
+	int			err;
+
+	dlp = netdev_priv(dev);
+
+	if (!*(short *)(dev->dev_addr))
+		return -EINVAL;
+
+	if (!netif_running(dlp->slave))
+		return -ENOTCONN;
+
+	flp = netdev_priv(dlp->slave);
+	err = (*flp->activate)(dlp->slave, dev);
+	if (err)
+		return err;
+
+	netif_start_queue(dev);
+
+	return 0;
+}
+
+static int dlci_close(struct net_device *dev)
+{
+	struct dlci_local	*dlp;
+	struct frad_local	*flp;
+	int			err;
+
+	netif_stop_queue(dev);
+
+	dlp = netdev_priv(dev);
+
+	flp = netdev_priv(dlp->slave);
+	err = (*flp->deactivate)(dlp->slave, dev);
+
+	return 0;
+}
+
+static int dlci_add(struct dlci_add *dlci)
+{
+	struct net_device	*master, *slave;
+	struct dlci_local	*dlp;
+	struct frad_local	*flp;
+	int			err = -EINVAL;
+
+
+	/* validate slave device */
+	slave = dev_get_by_name(&init_net, dlci->devname);
+	if (!slave)
+		return -ENODEV;
+
+	if (slave->type != ARPHRD_FRAD || netdev_priv(slave) == NULL)
+		goto err1;
+
+	/* create device name */
+	master = alloc_netdev(sizeof(struct dlci_local), "dlci%d",
+			      NET_NAME_UNKNOWN, dlci_setup);
+	if (!master) {
+		err = -ENOMEM;
+		goto err1;
+	}
+
+	/* make sure same slave not already registered */
+	rtnl_lock();
+	list_for_each_entry(dlp, &dlci_devs, list) {
+		if (dlp->slave == slave) {
+			err = -EBUSY;
+			goto err2;
+		}
+	}
+
+	*(short *)(master->dev_addr) = dlci->dlci;
+
+	dlp = netdev_priv(master);
+	dlp->slave = slave;
+	dlp->master = master;
+
+	flp = netdev_priv(slave);
+	err = (*flp->assoc)(slave, master);
+	if (err < 0)
+		goto err2;
+
+	err = register_netdevice(master);
+	if (err < 0) 
+		goto err2;
+
+	strcpy(dlci->devname, master->name);
+
+	list_add(&dlp->list, &dlci_devs);
+	rtnl_unlock();
+
+	return 0;
+
+ err2:
+	rtnl_unlock();
+	free_netdev(master);
+ err1:
+	dev_put(slave);
+	return err;
+}
+
+static int dlci_del(struct dlci_add *dlci)
+{
+	struct dlci_local	*dlp;
+	struct frad_local	*flp;
+	struct net_device	*master, *slave;
+	int			err;
+	bool			found = false;
+
+	rtnl_lock();
+
+	/* validate slave device */
+	master = __dev_get_by_name(&init_net, dlci->devname);
+	if (!master) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	list_for_each_entry(dlp, &dlci_devs, list) {
+		if (dlp->master == master) {
+			found = true;
+			break;
+		}
+	}
+	if (!found) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	if (netif_running(master)) {
+		err = -EBUSY;
+		goto out;
+	}
+
+	dlp = netdev_priv(master);
+	slave = dlp->slave;
+	flp = netdev_priv(slave);
+
+	err = (*flp->deassoc)(slave, master);
+	if (!err) {
+		list_del(&dlp->list);
+
+		unregister_netdevice(master);
+
+		dev_put(slave);
+	}
+out:
+	rtnl_unlock();
+	return err;
+}
+
+static int dlci_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct dlci_add add;
+	int err;
+	
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&add, arg, sizeof(struct dlci_add)))
+		return -EFAULT;
+
+	switch (cmd)
+	{
+		case SIOCADDDLCI:
+			err = dlci_add(&add);
+
+			if (!err)
+				if (copy_to_user(arg, &add, sizeof(struct dlci_add)))
+					return -EFAULT;
+			break;
+
+		case SIOCDELDLCI:
+			err = dlci_del(&add);
+			break;
+
+		default:
+			err = -EINVAL;
+	}
+
+	return err;
+}
+
+static const struct header_ops dlci_header_ops = {
+	.create	= dlci_header,
+};
+
+static const struct net_device_ops dlci_netdev_ops = {
+	.ndo_open	= dlci_open,
+	.ndo_stop	= dlci_close,
+	.ndo_do_ioctl	= dlci_dev_ioctl,
+	.ndo_start_xmit	= dlci_transmit,
+	.ndo_change_mtu	= dlci_change_mtu,
+};
+
+static void dlci_setup(struct net_device *dev)
+{
+	struct dlci_local *dlp = netdev_priv(dev);
+
+	dev->flags		= 0;
+	dev->header_ops		= &dlci_header_ops;
+	dev->netdev_ops		= &dlci_netdev_ops;
+	dev->needs_free_netdev	= true;
+
+	dlp->receive		= dlci_receive;
+
+	dev->type		= ARPHRD_DLCI;
+	dev->hard_header_len	= sizeof(struct frhdr);
+	dev->addr_len		= sizeof(short);
+
+}
+
+/* if slave is unregistering, then cleanup master */
+static int dlci_dev_event(struct notifier_block *unused,
+			  unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (dev_net(dev) != &init_net)
+		return NOTIFY_DONE;
+
+	if (event == NETDEV_UNREGISTER) {
+		struct dlci_local *dlp;
+
+		list_for_each_entry(dlp, &dlci_devs, list) {
+			if (dlp->slave == dev) {
+				list_del(&dlp->list);
+				unregister_netdevice(dlp->master);
+				dev_put(dlp->slave);
+				break;
+			}
+		}
+	}
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block dlci_notifier = {
+	.notifier_call = dlci_dev_event,
+};
+
+static int __init init_dlci(void)
+{
+	dlci_ioctl_set(dlci_ioctl);
+	register_netdevice_notifier(&dlci_notifier);
+
+	printk("%s.\n", version);
+
+	return 0;
+}
+
+static void __exit dlci_exit(void)
+{
+	struct dlci_local	*dlp, *nxt;
+	
+	dlci_ioctl_set(NULL);
+	unregister_netdevice_notifier(&dlci_notifier);
+
+	rtnl_lock();
+	list_for_each_entry_safe(dlp, nxt, &dlci_devs, list) {
+		unregister_netdevice(dlp->master);
+		dev_put(dlp->slave);
+	}
+	rtnl_unlock();
+}
+
+module_init(init_dlci);
+module_exit(dlci_exit);
+
+MODULE_AUTHOR("Mike McLagan");
+MODULE_DESCRIPTION("Frame Relay DLCI layer");
+MODULE_LICENSE("GPL");