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 */ 116