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         __be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
  47         struct module *module;
  48         struct hdlc_proto *next; /* next protocol in the list */
  49 };
  50
  51
  52 typedef struct hdlc_device {
  53         /* used by HDLC layer to take control over HDLC device from hw driver*/
  54         int (*attach)(struct net_device *dev,
  55                       unsigned short encoding, unsigned short parity);
  56
  57         /* hardware driver must handle this instead of dev->hard_start_xmit */
  58         int (*xmit)(struct sk_buff *skb, struct net_device *dev);
  59
  60         /* Things below are for HDLC layer internal use only */
  61         const struct hdlc_proto *proto;
  62         int carrier;
  63         int open;
  64         spinlock_t state_lock;
  65         void *state;
  66         void *priv;
  67 }hdlc_device;
  68
  69
  70
  71 /* Exported from hdlc module */
  72
  73 /* Called by hardware driver when a user requests HDLC service */
  74 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
  75
  76 /* Must be used by hardware driver on module startup/exit */
  77 #define register_hdlc_device(dev)       register_netdev(dev)
  78 void unregister_hdlc_device(struct net_device *dev);
  79
  80
  81 void register_hdlc_protocol(struct hdlc_proto *proto);
  82 void unregister_hdlc_protocol(struct hdlc_proto *proto);
  83
  84 struct net_device *alloc_hdlcdev(void *priv);
  85
  86
  87 static __inline__ struct hdlc_device_desc* dev_to_desc(struct net_device *dev)
  88 {
  89         return netdev_priv(dev);
  90 }
  91
  92 static __inline__ hdlc_device* dev_to_hdlc(struct net_device *dev)
  93 {
  94         return netdev_priv(dev) + sizeof(struct hdlc_device_desc);
  95 }
  96
  97
  98 static __inline__ void debug_frame(const struct sk_buff *skb)
  99 {
 100         int i;
 101
 102         for (i=0; i < skb->len; i++) {
 103                 if (i == 100) {
 104                         printk("...\n");
 105                         return;
 106                 }
 107                 printk(" %02X", skb->data[i]);
 108         }
 109         printk("\n");
 110 }
 111
 112
 113 /* Must be called by hardware driver when HDLC device is being opened */
 114 int hdlc_open(struct net_device *dev);
 115 /* Must be called by hardware driver when HDLC device is being closed */
 116 void hdlc_close(struct net_device *dev);
 117
 118 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 119                          int (*rx)(struct sk_buff *skb), size_t size);
 120 /* May be used by hardware driver to gain control over HDLC device */
 121 void detach_hdlc_protocol(struct net_device *dev);
 122
 123 static __inline__ struct net_device_stats *hdlc_stats(struct net_device *dev)
 124 {
 125         return &dev_to_desc(dev)->stats;
 126 }
 127
 128
 129 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 130                                          struct net_device *dev)
 131 {
 132         hdlc_device *hdlc = dev_to_hdlc(dev);
 133
 134         skb->dev = dev;
 135         skb_reset_mac_header(skb);
 136
 137         if (hdlc->proto->type_trans)
 138                 return hdlc->proto->type_trans(skb, dev);
 139         else
 140                 return htons(ETH_P_HDLC);
 141 }
 142
 143 #endif /* __KERNEL */
 144 #endif /* __HDLC_H */