include/linux/hdlc.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Generic HDLC support routines for Linux
   4  *
   5  * Copyright (C) 1999-2005 Krzysztof Halasa <khc@pm.waw.pl>
   6  */
   7 #ifndef __HDLC_H
   8 #define __HDLC_H
   9
  10
  11 #include <linux/skbuff.h>
  12 #include <linux/netdevice.h>
  13 #include <linux/hdlc/ioctl.h>
  14 #include <uapi/linux/hdlc.h>
  15
  16 /* This structure is a private property of HDLC protocols.
  17    Hardware drivers have no interest here */
  18
  19 struct hdlc_proto {
  20         int (*open)(struct net_device *dev);
  21         void (*close)(struct net_device *dev);
  22         void (*start)(struct net_device *dev); /* if open & DCD */
  23         void (*stop)(struct net_device *dev); /* if open & !DCD */
  24         void (*detach)(struct net_device *dev);
  25         int (*ioctl)(struct net_device *dev, struct if_settings *ifs);
  26         __be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
  27         int (*netif_rx)(struct sk_buff *skb);
  28         netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
  29         struct module *module;
  30         struct hdlc_proto *next; /* next protocol in the list */
  31 };
  32
  33
  34 /* Pointed to by netdev_priv(dev) */
  35 typedef struct hdlc_device {
  36         /* used by HDLC layer to take control over HDLC device from hw driver*/
  37         int (*attach)(struct net_device *dev,
  38                       unsigned short encoding, unsigned short parity);
  39
  40         /* hardware driver must handle this instead of dev->hard_start_xmit */
  41         netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
  42
  43         /* Things below are for HDLC layer internal use only */
  44         const struct hdlc_proto *proto;
  45         int carrier;
  46         int open;
  47         spinlock_t state_lock;
  48         void *state;
  49         void *priv;
  50 } hdlc_device;
  51
  52
  53
  54 /* Exported from hdlc module */
  55
  56 /* Called by hardware driver when a user requests HDLC service */
  57 int hdlc_ioctl(struct net_device *dev, struct if_settings *ifs);
  58
  59 /* Must be used by hardware driver on module startup/exit */
  60 #define register_hdlc_device(dev)       register_netdev(dev)
  61 void unregister_hdlc_device(struct net_device *dev);
  62
  63
  64 void register_hdlc_protocol(struct hdlc_proto *proto);
  65 void unregister_hdlc_protocol(struct hdlc_proto *proto);
  66
  67 struct net_device *alloc_hdlcdev(void *priv);
  68
  69 static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
  70 {
  71         return netdev_priv(dev);
  72 }
  73
  74 static __inline__ void debug_frame(const struct sk_buff *skb)
  75 {
  76         int i;
  77
  78         for (i=0; i < skb->len; i++) {
  79                 if (i == 100) {
  80                         printk("...\n");
  81                         return;
  82                 }
  83                 printk(" %02X", skb->data[i]);
  84         }
  85         printk("\n");
  86 }
  87
  88
  89 /* Must be called by hardware driver when HDLC device is being opened */
  90 int hdlc_open(struct net_device *dev);
  91 /* Must be called by hardware driver when HDLC device is being closed */
  92 void hdlc_close(struct net_device *dev);
  93 /* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
  94 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
  95
  96 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
  97                          size_t size);
  98 /* May be used by hardware driver to gain control over HDLC device */
  99 int detach_hdlc_protocol(struct net_device *dev);
 100
 101 static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 102                                          struct net_device *dev)
 103 {
 104         hdlc_device *hdlc = dev_to_hdlc(dev);
 105
 106         skb->dev = dev;
 107         skb_reset_mac_header(skb);
 108
 109         if (hdlc->proto->type_trans)
 110                 return hdlc->proto->type_trans(skb, dev);
 111         else
 112                 return htons(ETH_P_HDLC);
 113 }
 114
 115 #endif /* __HDLC_H */