File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/net/wan/hdlc_raw.c b/drivers/net/wan/hdlc_raw.c
new file mode 100644
index 0000000..5dc153e
--- /dev/null
+++ b/drivers/net/wan/hdlc_raw.c
@@ -0,0 +1,114 @@
+/*
+ * Generic HDLC support routines for Linux
+ * HDLC support
+ *
+ * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ */
+
+#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/pkt_sched.h>
+#include <linux/poll.h>
+#include <linux/rtnetlink.h>
+#include <linux/skbuff.h>
+
+
+static int raw_ioctl(struct net_device *dev, struct ifreq *ifr);
+
+static __be16 raw_type_trans(struct sk_buff *skb, struct net_device *dev)
+{
+	return cpu_to_be16(ETH_P_IP);
+}
+
+static struct hdlc_proto proto = {
+	.type_trans	= raw_type_trans,
+	.ioctl		= raw_ioctl,
+	.module		= THIS_MODULE,
+};
+
+
+static int raw_ioctl(struct net_device *dev, struct ifreq *ifr)
+{
+	raw_hdlc_proto __user *raw_s = ifr->ifr_settings.ifs_ifsu.raw_hdlc;
+	const size_t size = sizeof(raw_hdlc_proto);
+	raw_hdlc_proto new_settings;
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	int result;
+
+	switch (ifr->ifr_settings.type) {
+	case IF_GET_PROTO:
+		if (dev_to_hdlc(dev)->proto != &proto)
+			return -EINVAL;
+		ifr->ifr_settings.type = IF_PROTO_HDLC;
+		if (ifr->ifr_settings.size < size) {
+			ifr->ifr_settings.size = size; /* data size wanted */
+			return -ENOBUFS;
+		}
+		if (copy_to_user(raw_s, hdlc->state, size))
+			return -EFAULT;
+		return 0;
+
+	case IF_PROTO_HDLC:
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+
+		if (dev->flags & IFF_UP)
+			return -EBUSY;
+
+		if (copy_from_user(&new_settings, raw_s, size))
+			return -EFAULT;
+
+		if (new_settings.encoding == ENCODING_DEFAULT)
+			new_settings.encoding = ENCODING_NRZ;
+
+		if (new_settings.parity == PARITY_DEFAULT)
+			new_settings.parity = PARITY_CRC16_PR1_CCITT;
+
+		result = hdlc->attach(dev, new_settings.encoding,
+				      new_settings.parity);
+		if (result)
+			return result;
+
+		result = attach_hdlc_protocol(dev, &proto,
+					      sizeof(raw_hdlc_proto));
+		if (result)
+			return result;
+		memcpy(hdlc->state, &new_settings, size);
+		dev->type = ARPHRD_RAWHDLC;
+		netif_dormant_off(dev);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+
+static int __init mod_init(void)
+{
+	register_hdlc_protocol(&proto);
+	return 0;
+}
+
+
+
+static void __exit mod_exit(void)
+{
+	unregister_hdlc_protocol(&proto);
+}
+
+
+module_init(mod_init);
+module_exit(mod_exit);
+
+MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
+MODULE_DESCRIPTION("Raw HDLC protocol support for generic HDLC");
+MODULE_LICENSE("GPL v2");