linux/include/linux/hdlc.h
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   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
  22struct 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) */
  38typedef 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 */
  60int 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)
  64void unregister_hdlc_device(struct net_device *dev);
  65
  66
  67void register_hdlc_protocol(struct hdlc_proto *proto);
  68void unregister_hdlc_protocol(struct hdlc_proto *proto);
  69
  70struct net_device *alloc_hdlcdev(void *priv);
  71
  72static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
  73{
  74        return netdev_priv(dev);
  75}
  76
  77static __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 */
  93int hdlc_open(struct net_device *dev);
  94/* Must be called by hardware driver when HDLC device is being closed */
  95void hdlc_close(struct net_device *dev);
  96/* May be used by hardware driver */
  97int 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 */
  99netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
 100
 101int 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 */
 104void detach_hdlc_protocol(struct net_device *dev);
 105
 106static __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 */
 121
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