1 files changed, 115 insertions, 0 deletions
diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
new file mode 100644
index 000000000..630a38803
--- /dev/null
+++ b/include/linux/hdlc.h
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Generic HDLC support routines for Linux
+ *
+ * Copyright (C) 1999-2005 Krzysztof Halasa <khc@pm.waw.pl>
+ */
+#ifndef __HDLC_H
+#define __HDLC_H
+
+
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/hdlc/ioctl.h>
+#include <uapi/linux/hdlc.h>
+
+/* This structure is a private property of HDLC protocols.
+   Hardware drivers have no interest here */
+
+struct hdlc_proto {
+	int (*open)(struct net_device *dev);
+	void (*close)(struct net_device *dev);
+	void (*start)(struct net_device *dev); /* if open & DCD */
+	void (*stop)(struct net_device *dev); /* if open & !DCD */
+	void (*detach)(struct net_device *dev);
+	int (*ioctl)(struct net_device *dev, struct if_settings *ifs);
+	__be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
+	int (*netif_rx)(struct sk_buff *skb);
+	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
+	struct module *module;
+	struct hdlc_proto *next; /* next protocol in the list */
+};
+
+
+/* Pointed to by netdev_priv(dev) */
+typedef struct hdlc_device {
+	/* 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 */
+	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
+
+	/* Things below are for HDLC layer internal use only */
+	const struct hdlc_proto *proto;
+	int carrier;
+	int open;
+	spinlock_t state_lock;
+	void *state;
+	void *priv;
+} hdlc_device;
+
+
+
+/* Exported from hdlc module */
+
+/* Called by hardware driver when a user requests HDLC service */
+int hdlc_ioctl(struct net_device *dev, struct if_settings *ifs);
+
+/* Must be used by hardware driver on module startup/exit */
+#define register_hdlc_device(dev)	register_netdev(dev)
+void unregister_hdlc_device(struct net_device *dev);
+
+
+void register_hdlc_protocol(struct hdlc_proto *proto);
+void unregister_hdlc_protocol(struct hdlc_proto *proto);
+
+struct net_device *alloc_hdlcdev(void *priv);
+
+static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
+{
+	return netdev_priv(dev);
+}
+
+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);
+/* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
+netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
+
+int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
+			 size_t size);
+/* May be used by hardware driver to gain control over HDLC device */
+int detach_hdlc_protocol(struct net_device *dev);
+
+static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
+					 struct net_device *dev)
+{
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+
+	skb->dev = dev;
+	skb_reset_mac_header(skb);
+
+	if (hdlc->proto->type_trans)
+		return hdlc->proto->type_trans(skb, dev);
+	else
+		return htons(ETH_P_HDLC);
+}
+
+#endif /* __HDLC_H */