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         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
  82 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
  83 {
  84         return netdev_priv(dev);
  85 }
  86
  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
 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 */