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
  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         struct module *module;
  42         struct hdlc_proto *next; /* next protocol in the list */
  43 };
  44
  45
  46 /* Pointed to by netdev_priv(dev) */
  47 typedef struct hdlc_device {
  48         /* used by HDLC layer to take control over HDLC device from hw driver*/
  49         int (*attach)(struct net_device *dev,
  50                       unsigned short encoding, unsigned short parity);
  51
  52         /* hardware driver must handle this instead of dev->hard_start_xmit */
  53         int (*xmit)(struct sk_buff *skb, struct net_device *dev);
  54
  55         /* Things below are for HDLC layer internal use only */
  56         const struct hdlc_proto *proto;
  57         int carrier;
  58         int open;
  59         spinlock_t state_lock;
  60         void *state;
  61         void *priv;
  62 }hdlc_device;
  63
  64
  65
  66 /* Exported from hdlc module */
  67
  68 /* Called by hardware driver when a user requests HDLC service */
  69 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
  70
  71 /* Must be used by hardware driver on module startup/exit */
  72 #define register_hdlc_device(dev)       register_netdev(dev)
  73 void unregister_hdlc_device(struct net_device *dev);
  74
  75
  76 void register_hdlc_protocol(struct hdlc_proto *proto);
  77 void unregister_hdlc_protocol(struct hdlc_proto *proto);
  78
  79 struct net_device *alloc_hdlcdev(void *priv);
  80
  81 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
  82 {
  83         return netdev_priv(dev);
  84 }
  85
  86 static __inline__ void debug_frame(const struct sk_buff *skb)
  87 {
  88         int i;
  89
  90         for (i=0; i < skb->len; i++) {
  91                 if (i == 100) {
  92                         printk("...\n");
  93                         return;
  94                 }
  95                 printk(" %02X", skb->data[i]);
  96         }
  97         printk("\n");
  98 }
  99
 100
 101 /* Must be called by hardware driver when HDLC device is being opened */
 102 int hdlc_open(struct net_device *dev);
 103 /* Must be called by hardware driver when HDLC device is being closed */
 104 void hdlc_close(struct net_device *dev);
 105
 106 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 107                          size_t size);
 108 /* May be used by hardware driver to gain control over HDLC device */
 109 void detach_hdlc_protocol(struct net_device *dev);
 110
 111 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 112                                          struct net_device *dev)
 113 {
 114         hdlc_device *hdlc = dev_to_hdlc(dev);
 115
 116         skb->dev = dev;
 117         skb_reset_mac_header(skb);
 118
 119         if (hdlc->proto->type_trans)
 120                 return hdlc->proto->type_trans(skb, dev);
 121         else
 122                 return htons(ETH_P_HDLC);
 123 }
 124
 125 #endif /* __KERNEL */
 126 #endif /* __HDLC_H */