hdlc.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Generic HDLC support routines for Linux
  4 *
  5 * Copyright (C) 1999-2005 Krzysztof Halasa <khc@pm.waw.pl>
  6 */
  7#ifndef __HDLC_H
  8#define __HDLC_H
  9
 10
 11#include <linux/skbuff.h>
 12#include <linux/netdevice.h>
 13#include <linux/hdlc/ioctl.h>
 14#include <uapi/linux/hdlc.h>
 15
 16/* This structure is a private property of HDLC protocols.
 17   Hardware drivers have no interest here */
 18
 19struct hdlc_proto {
 20	int (*open)(struct net_device *dev);
 21	void (*close)(struct net_device *dev);
 22	void (*start)(struct net_device *dev); /* if open & DCD */
 23	void (*stop)(struct net_device *dev); /* if open & !DCD */
 24	void (*detach)(struct net_device *dev);
 25	int (*ioctl)(struct net_device *dev, struct if_settings *ifs);
 26	__be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
 27	int (*netif_rx)(struct sk_buff *skb);
 28	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
 29	struct module *module;
 30	struct hdlc_proto *next; /* next protocol in the list */
 31};
 32
 33
 34/* Pointed to by netdev_priv(dev) */
 35typedef struct hdlc_device {
 36	/* used by HDLC layer to take control over HDLC device from hw driver*/
 37	int (*attach)(struct net_device *dev,
 38		      unsigned short encoding, unsigned short parity);
 39
 40	/* hardware driver must handle this instead of dev->hard_start_xmit */
 41	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
 42
 43	/* Things below are for HDLC layer internal use only */
 44	const struct hdlc_proto *proto;
 45	int carrier;
 46	int open;
 47	spinlock_t state_lock;
 48	void *state;
 49	void *priv;
 50} hdlc_device;
 51
 52
 53
 54/* Exported from hdlc module */
 55
 56/* Called by hardware driver when a user requests HDLC service */
 57int hdlc_ioctl(struct net_device *dev, struct if_settings *ifs);
 58
 59/* Must be used by hardware driver on module startup/exit */
 60#define register_hdlc_device(dev)	register_netdev(dev)
 61void unregister_hdlc_device(struct net_device *dev);
 62
 63
 64void register_hdlc_protocol(struct hdlc_proto *proto);
 65void unregister_hdlc_protocol(struct hdlc_proto *proto);
 66
 67struct net_device *alloc_hdlcdev(void *priv);
 68
 69static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
 70{
 71	return netdev_priv(dev);
 72}
 73
 74static __inline__ void debug_frame(const struct sk_buff *skb)
 75{
 76	int i;
 77
 78	for (i=0; i < skb->len; i++) {
 79		if (i == 100) {
 80			printk("...\n");
 81			return;
 82		}
 83		printk(" %02X", skb->data[i]);
 84	}
 85	printk("\n");
 86}
 87
 88
 89/* Must be called by hardware driver when HDLC device is being opened */
 90int hdlc_open(struct net_device *dev);
 91/* Must be called by hardware driver when HDLC device is being closed */
 92void hdlc_close(struct net_device *dev);
 93/* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
 94netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
 95
 96int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 97			 size_t size);
 98/* May be used by hardware driver to gain control over HDLC device */
 99int detach_hdlc_protocol(struct net_device *dev);
100
101static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
102					 struct net_device *dev)
103{
104	hdlc_device *hdlc = dev_to_hdlc(dev);
105
106	skb->dev = dev;
107	skb_reset_mac_header(skb);
108
109	if (hdlc->proto->type_trans)
110		return hdlc->proto->type_trans(skb, dev);
111	else
112		return htons(ETH_P_HDLC);
113}
114
115#endif /* __HDLC_H */