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
  30 /* Used by all network devices here, pointed to by netdev_priv(dev) */
  31 struct hdlc_device_desc {
  32         int (*netif_rx)(struct sk_buff *skb);
  33         struct net_device_stats stats;
  34 };
  35
  36 /* This structure is a private property of HDLC protocols.
  37    Hardware drivers have no interest here */
  38
  39 struct hdlc_proto {
  40         int (*open)(struct net_device *dev);
  41         void (*close)(struct net_device *dev);
  42         void (*start)(struct net_device *dev); /* if open & DCD */
  43         void (*stop)(struct net_device *dev); /* if open & !DCD */
  44         void (*detach)(struct net_device *dev);
  45         int (*ioctl)(struct net_device *dev, struct ifreq *ifr);
  46         unsigned short (*type_trans)(struct sk_buff *skb,
  47                                      struct net_device *dev);
  48         struct module *module;
  49         struct hdlc_proto *next; /* next protocol in the list */
  50 };
  51
  52
  53 typedef struct hdlc_device {
  54         /* used by HDLC layer to take control over HDLC device from hw driver*/
  55         int (*attach)(struct net_device *dev,
  56                       unsigned short encoding, unsigned short parity);
  57
  58         /* hardware driver must handle this instead of dev->hard_start_xmit */
  59         int (*xmit)(struct sk_buff *skb, struct net_device *dev);
  60
  61         /* Things below are for HDLC layer internal use only */
  62         const struct hdlc_proto *proto;
  63         int carrier;
  64         int open;
  65         spinlock_t state_lock;
  66         void *state;
  67         void *priv;
  68 }hdlc_device;
  69
  70
  71
  72 /* Exported from hdlc module */
  73
  74 /* Called by hardware driver when a user requests HDLC service */
  75 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
  76
  77 /* Must be used by hardware driver on module startup/exit */
  78 #define register_hdlc_device(dev)       register_netdev(dev)
  79 void unregister_hdlc_device(struct net_device *dev);
  80
  81
  82 void register_hdlc_protocol(struct hdlc_proto *proto);
  83 void unregister_hdlc_protocol(struct hdlc_proto *proto);
  84
  85 struct net_device *alloc_hdlcdev(void *priv);
  86
  87
  88 static __inline__ struct hdlc_device_desc* dev_to_desc(struct net_device *dev)
  89 {
  90         return netdev_priv(dev);
  91 }
  92
  93 static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
  94 {
  95         return netdev_priv(dev) + sizeof(struct hdlc_device_desc);
  96 }
  97
  98
  99 static __inline__ void debug_frame(const struct sk_buff *skb)
 100 {
 101         int i;
 102
 103         for (i=0; i < skb->len; i++) {
 104                 if (i == 100) {
 105                         printk("...\n");
 106                         return;
 107                 }
 108                 printk(" %02X", skb->data[i]);
 109         }
 110         printk("\n");
 111 }
 112
 113
 114 /* Must be called by hardware driver when HDLC device is being opened */
 115 int hdlc_open(struct net_device *dev);
 116 /* Must be called by hardware driver when HDLC device is being closed */
 117 void hdlc_close(struct net_device *dev);
 118
 119 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 120                          int (*rx)(struct sk_buff *skb), size_t size);
 121 /* May be used by hardware driver to gain control over HDLC device */
 122 void detach_hdlc_protocol(struct net_device *dev);
 123
 124 static __inline__ struct net_device_stats *hdlc_stats(struct net_device *dev)
 125 {
 126         return &dev_to_desc(dev)->stats;
 127 }
 128
 129
 130 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 131                                          struct net_device *dev)
 132 {
 133         hdlc_device *hdlc = dev_to_hdlc(dev);
 134
 135         skb->dev = dev;
 136         skb_reset_mac_header(skb);
 137
 138         if (hdlc->proto->type_trans)
 139                 return hdlc->proto->type_trans(skb, dev);
 140         else
 141                 return htons(ETH_P_HDLC);
 142 }
 143
 144 #endif /* __KERNEL */
 145 #endif /* __HDLC_H */