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 */
116

source code of linux/include/linux/hdlc.h