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
32 struct 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) */
48 typedef 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 */
70 int 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)
74 void unregister_hdlc_device(struct net_device *dev);
75
76
77 void register_hdlc_protocol(struct hdlc_proto *proto);
78 void unregister_hdlc_protocol(struct hdlc_proto *proto);
79
80 struct net_device *alloc_hdlcdev(void *priv);
81
dev_to_hdlc(struct net_device * dev)82 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
83 {
84 return netdev_priv(dev);
85 }
86
debug_frame(const struct sk_buff * skb)87 static __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 */
103 int hdlc_open(struct net_device *dev);
104 /* Must be called by hardware driver when HDLC device is being closed */
105 void hdlc_close(struct net_device *dev);
106 /* May be used by hardware driver */
107 int 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 */
109 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
110
111 int 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 */
114 void detach_hdlc_protocol(struct net_device *dev);
115
hdlc_type_trans(struct sk_buff * skb,struct net_device * dev)116 static __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