1/*
2 * Generic HDLC support routines for Linux
3 *
4 * Copyright (C) 1999-2005 Krzysztof Halasa <khc@pm.waw.pl>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of version 2 of the GNU General Public License
8 * as published by the Free Software Foundation.
9 */
10
11#ifndef __HDLC_H
12#define __HDLC_H
13
14
15#define HDLC_MAX_MTU 1500	/* Ethernet 1500 bytes */
16#if 0
17#define HDLC_MAX_MRU (HDLC_MAX_MTU + 10 + 14 + 4) /* for ETH+VLAN over FR */
18#else
19#define HDLC_MAX_MRU 1600 /* as required for FR network */
20#endif
21
22
23#ifdef __KERNEL__
24
25#include <linux/skbuff.h>
26#include <linux/netdevice.h>
27#include <linux/hdlc/ioctl.h>
28
29/* This structure is a private property of HDLC protocols.
30   Hardware drivers have no interest here */
31
32struct hdlc_proto {
33	int (*open)(struct net_device *dev);
34	void (*close)(struct net_device *dev);
35	void (*start)(struct net_device *dev); /* if open & DCD */
36	void (*stop)(struct net_device *dev); /* if open & !DCD */
37	void (*detach)(struct net_device *dev);
38	int (*ioctl)(struct net_device *dev, struct ifreq *ifr);
39	__be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
40	int (*netif_rx)(struct sk_buff *skb);
41	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
42	struct module *module;
43	struct hdlc_proto *next; /* next protocol in the list */
44};
45
46
47/* Pointed to by netdev_priv(dev) */
48typedef struct hdlc_device {
49	/* used by HDLC layer to take control over HDLC device from hw driver*/
50	int (*attach)(struct net_device *dev,
51		      unsigned short encoding, unsigned short parity);
52
53	/* hardware driver must handle this instead of dev->hard_start_xmit */
54	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
55
56	/* Things below are for HDLC layer internal use only */
57	const struct hdlc_proto *proto;
58	int carrier;
59	int open;
60	spinlock_t state_lock;
61	void *state;
62	void *priv;
63} hdlc_device;
64
65
66
67/* Exported from hdlc module */
68
69/* Called by hardware driver when a user requests HDLC service */
70int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
71
72/* Must be used by hardware driver on module startup/exit */
73#define register_hdlc_device(dev)	register_netdev(dev)
74void unregister_hdlc_device(struct net_device *dev);
75
76
77void register_hdlc_protocol(struct hdlc_proto *proto);
78void unregister_hdlc_protocol(struct hdlc_proto *proto);
79
80struct net_device *alloc_hdlcdev(void *priv);
81
82static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
83{
84	return netdev_priv(dev);
85}
86
87static __inline__ void debug_frame(const struct sk_buff *skb)
88{
89	int i;
90
91	for (i=0; i < skb->len; i++) {
92		if (i == 100) {
93			printk("...\n");
94			return;
95		}
96		printk(" %02X", skb->data[i]);
97	}
98	printk("\n");
99}
100
101
102/* Must be called by hardware driver when HDLC device is being opened */
103int hdlc_open(struct net_device *dev);
104/* Must be called by hardware driver when HDLC device is being closed */
105void hdlc_close(struct net_device *dev);
106/* May be used by hardware driver */
107int hdlc_change_mtu(struct net_device *dev, int new_mtu);
108/* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
109netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
110
111int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
112			 size_t size);
113/* May be used by hardware driver to gain control over HDLC device */
114void detach_hdlc_protocol(struct net_device *dev);
115
116static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
117					 struct net_device *dev)
118{
119	hdlc_device *hdlc = dev_to_hdlc(dev);
120
121	skb->dev = dev;
122	skb_reset_mac_header(skb);
123
124	if (hdlc->proto->type_trans)
125		return hdlc->proto->type_trans(skb, dev);
126	else
127		return htons(ETH_P_HDLC);
128}
129
130#endif /* __KERNEL */
131#endif /* __HDLC_H */
132