include/linux/hdlc.h

   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 #ifndef __HDLC_H
  11 #define __HDLC_H
  12
  13
  14 #include <linux/skbuff.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/hdlc/ioctl.h>
  17 #include <uapi/linux/hdlc.h>
  18
  19 /* This structure is a private property of HDLC protocols.
  20    Hardware drivers have no interest here */
  21
  22 struct hdlc_proto {
  23         int (*open)(struct net_device *dev);
  24         void (*close)(struct net_device *dev);
  25         void (*start)(struct net_device *dev); /* if open & DCD */
  26         void (*stop)(struct net_device *dev); /* if open & !DCD */
  27         void (*detach)(struct net_device *dev);
  28         int (*ioctl)(struct net_device *dev, struct ifreq *ifr);
  29         __be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
  30         int (*netif_rx)(struct sk_buff *skb);
  31         netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
  32         struct module *module;
  33         struct hdlc_proto *next; /* next protocol in the list */
  34 };
  35
  36
  37 /* Pointed to by netdev_priv(dev) */
  38 typedef struct hdlc_device {
  39         /* used by HDLC layer to take control over HDLC device from hw driver*/
  40         int (*attach)(struct net_device *dev,
  41                       unsigned short encoding, unsigned short parity);
  42
  43         /* hardware driver must handle this instead of dev->hard_start_xmit */
  44         netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
  45
  46         /* Things below are for HDLC layer internal use only */
  47         const struct hdlc_proto *proto;
  48         int carrier;
  49         int open;
  50         spinlock_t state_lock;
  51         void *state;
  52         void *priv;
  53 } hdlc_device;
  54
  55
  56
  57 /* Exported from hdlc module */
  58
  59 /* Called by hardware driver when a user requests HDLC service */
  60 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
  61
  62 /* Must be used by hardware driver on module startup/exit */
  63 #define register_hdlc_device(dev)       register_netdev(dev)
  64 void unregister_hdlc_device(struct net_device *dev);
  65
  66
  67 void register_hdlc_protocol(struct hdlc_proto *proto);
  68 void unregister_hdlc_protocol(struct hdlc_proto *proto);
  69
  70 struct net_device *alloc_hdlcdev(void *priv);
  71
  72 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
  73 {
  74         return netdev_priv(dev);
  75 }
  76
  77 static __inline__ void debug_frame(const struct sk_buff *skb)
  78 {
  79         int i;
  80
  81         for (i=0; i < skb->len; i++) {
  82                 if (i == 100) {
  83                         printk("...\n");
  84                         return;
  85                 }
  86                 printk(" %02X", skb->data[i]);
  87         }
  88         printk("\n");
  89 }
  90
  91
  92 /* Must be called by hardware driver when HDLC device is being opened */
  93 int hdlc_open(struct net_device *dev);
  94 /* Must be called by hardware driver when HDLC device is being closed */
  95 void hdlc_close(struct net_device *dev);
  96 /* May be used by hardware driver */
  97 int hdlc_change_mtu(struct net_device *dev, int new_mtu);
  98 /* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
  99 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
 100
 101 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 102                          size_t size);
 103 /* May be used by hardware driver to gain control over HDLC device */
 104 void detach_hdlc_protocol(struct net_device *dev);
 105
 106 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 107                                          struct net_device *dev)
 108 {
 109         hdlc_device *hdlc = dev_to_hdlc(dev);
 110
 111         skb->dev = dev;
 112         skb_reset_mac_header(skb);
 113
 114         if (hdlc->proto->type_trans)
 115                 return hdlc->proto->type_trans(skb, dev);
 116         else
 117                 return htons(ETH_P_HDLC);
 118 }
 119
 120 #endif /* __HDLC_H */