diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
new file mode 100644
index 0000000..503194e
--- /dev/null
+++ b/include/linux/hdlc.h
@@ -0,0 +1,258 @@
+/*
+ * Generic HDLC support routines for Linux
+ *
+ * Copyright (C) 1999-2003 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.
+ */
+
+#ifndef __HDLC_H
+#define __HDLC_H
+
+#define GENERIC_HDLC_VERSION 4	/* For synchronization with sethdlc utility */
+
+#define CLOCK_DEFAULT   0	/* Default setting */
+#define CLOCK_EXT	1	/* External TX and RX clock - DTE */
+#define CLOCK_INT	2	/* Internal TX and RX clock - DCE */
+#define CLOCK_TXINT	3	/* Internal TX and external RX clock */
+#define CLOCK_TXFROMRX	4	/* TX clock derived from external RX clock */
+
+
+#define ENCODING_DEFAULT	0 /* Default setting */
+#define ENCODING_NRZ		1
+#define ENCODING_NRZI		2
+#define ENCODING_FM_MARK	3
+#define ENCODING_FM_SPACE	4
+#define ENCODING_MANCHESTER	5
+
+
+#define PARITY_DEFAULT		0 /* Default setting */
+#define PARITY_NONE		1 /* No parity */
+#define PARITY_CRC16_PR0	2 /* CRC16, initial value 0x0000 */
+#define PARITY_CRC16_PR1	3 /* CRC16, initial value 0xFFFF */
+#define PARITY_CRC16_PR0_CCITT	4 /* CRC16, initial 0x0000, ITU-T version */
+#define PARITY_CRC16_PR1_CCITT	5 /* CRC16, initial 0xFFFF, ITU-T version */
+#define PARITY_CRC32_PR0_CCITT	6 /* CRC32, initial value 0x00000000 */
+#define PARITY_CRC32_PR1_CCITT	7 /* CRC32, initial value 0xFFFFFFFF */
+
+#define LMI_DEFAULT		0 /* Default setting */
+#define LMI_NONE		1 /* No LMI, all PVCs are static */
+#define LMI_ANSI		2 /* ANSI Annex D */
+#define LMI_CCITT		3 /* ITU-T Annex A */
+
+#define HDLC_MAX_MTU 1500	/* Ethernet 1500 bytes */
+#define HDLC_MAX_MRU (HDLC_MAX_MTU + 10 + 14 + 4) /* for ETH+VLAN over FR */
+
+
+#ifdef __KERNEL__
+
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <net/syncppp.h>
+#include <linux/hdlc/ioctl.h>
+
+
+typedef struct {		/* Used in Cisco and PPP mode */
+	u8 address;
+	u8 control;
+	u16 protocol;
+}__attribute__ ((packed)) hdlc_header;
+
+
+
+typedef struct {
+	u32 type;		/* code */
+	u32 par1;
+	u32 par2;
+	u16 rel;		/* reliability */
+	u32 time;
+}__attribute__ ((packed)) cisco_packet;
+#define	CISCO_PACKET_LEN	18
+#define	CISCO_BIG_PACKET_LEN	20
+
+
+
+typedef struct pvc_device_struct {
+	struct net_device *master;
+	struct net_device *main;
+	struct net_device *ether; /* bridged Ethernet interface */
+	struct pvc_device_struct *next;	/* Sorted in ascending DLCI order */
+	int dlci;
+	int open_count;
+
+	struct {
+		unsigned int new: 1;
+		unsigned int active: 1;
+		unsigned int exist: 1;
+		unsigned int deleted: 1;
+		unsigned int fecn: 1;
+		unsigned int becn: 1;
+	}state;
+}pvc_device;
+
+
+
+typedef struct hdlc_device_struct {
+	/* To be initialized by hardware driver */
+	struct net_device_stats stats;
+
+	/* used by HDLC layer to take control over HDLC device from hw driver*/
+	int (*attach)(struct net_device *dev,
+		      unsigned short encoding, unsigned short parity);
+
+	/* hardware driver must handle this instead of dev->hard_start_xmit */
+	int (*xmit)(struct sk_buff *skb, struct net_device *dev);
+
+
+	/* Things below are for HDLC layer internal use only */
+	struct {
+		int (*open)(struct net_device *dev);
+		void (*close)(struct net_device *dev);
+
+		/* if open & DCD */
+		void (*start)(struct net_device *dev);
+		/* if open & !DCD */
+		void (*stop)(struct net_device *dev);
+
+		void (*detach)(struct hdlc_device_struct *hdlc);
+		int (*netif_rx)(struct sk_buff *skb);
+		unsigned short (*type_trans)(struct sk_buff *skb,
+					     struct net_device *dev);
+		int id;		/* IF_PROTO_HDLC/CISCO/FR/etc. */
+	}proto;
+
+	int carrier;
+	int open;
+	spinlock_t state_lock;
+
+	union {
+		struct {
+			fr_proto settings;
+			pvc_device *first_pvc;
+			int dce_pvc_count;
+
+			struct timer_list timer;
+			unsigned long last_poll;
+			int reliable;
+			int dce_changed;
+			int request;
+			int fullrep_sent;
+			u32 last_errors; /* last errors bit list */
+			u8 n391cnt;
+			u8 txseq; /* TX sequence number */
+			u8 rxseq; /* RX sequence number */
+		}fr;
+
+		struct {
+			cisco_proto settings;
+
+			struct timer_list timer;
+			unsigned long last_poll;
+			int up;
+			int request_sent;
+			u32 txseq; /* TX sequence number */
+			u32 rxseq; /* RX sequence number */
+		}cisco;
+
+		struct {
+			raw_hdlc_proto settings;
+		}raw_hdlc;
+
+		struct {
+			struct ppp_device pppdev;
+			struct ppp_device *syncppp_ptr;
+			int (*old_change_mtu)(struct net_device *dev,
+					      int new_mtu);
+		}ppp;
+	}state;
+	void *priv;
+}hdlc_device;
+
+
+
+int hdlc_raw_ioctl(struct net_device *dev, struct ifreq *ifr);
+int hdlc_raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr);
+int hdlc_cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
+int hdlc_ppp_ioctl(struct net_device *dev, struct ifreq *ifr);
+int hdlc_fr_ioctl(struct net_device *dev, struct ifreq *ifr);
+int hdlc_x25_ioctl(struct net_device *dev, struct ifreq *ifr);
+
+
+/* Exported from hdlc.o */
+
+/* Called by hardware driver when a user requests HDLC service */
+int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
+
+/* Must be used by hardware driver on module startup/exit */
+int register_hdlc_device(struct net_device *dev);
+void unregister_hdlc_device(struct net_device *dev);
+
+struct net_device *alloc_hdlcdev(void *priv);
+
+static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
+{
+	return netdev_priv(dev);
+}
+
+
+static __inline__ pvc_device* dev_to_pvc(struct net_device *dev)
+{
+	return (pvc_device*)dev->priv;
+}
+
+
+static __inline__ void debug_frame(const struct sk_buff *skb)
+{
+	int i;
+
+	for (i=0; i < skb->len; i++) {
+		if (i == 100) {
+			printk("...\n");
+			return;
+		}
+		printk(" %02X", skb->data[i]);
+	}
+	printk("\n");
+}
+
+
+/* Must be called by hardware driver when HDLC device is being opened */
+int hdlc_open(struct net_device *dev);
+/* Must be called by hardware driver when HDLC device is being closed */
+void hdlc_close(struct net_device *dev);
+/* Called by hardware driver when DCD line level changes */
+void hdlc_set_carrier(int on, struct net_device *dev);
+
+/* May be used by hardware driver to gain control over HDLC device */
+static __inline__ void hdlc_proto_detach(hdlc_device *hdlc)
+{
+	if (hdlc->proto.detach)
+		hdlc->proto.detach(hdlc);
+	hdlc->proto.detach = NULL;
+}
+
+
+static __inline__ struct net_device_stats *hdlc_stats(struct net_device *dev)
+{
+	return &dev_to_hdlc(dev)->stats;
+}
+
+
+static __inline__ unsigned short hdlc_type_trans(struct sk_buff *skb,
+						 struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+
+	skb->mac.raw  = skb->data;
+	skb->dev      = dev;
+
+	if (hdlc->proto.type_trans)
+		return hdlc->proto.type_trans(skb, dev);
+	else
+		return htons(ETH_P_HDLC);
+}
+
+#endif /* __KERNEL */
+#endif /* __HDLC_H */