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![Andrew Lunn](/assets/img/avatar_default.png)
An HDLC device can change type when the protocol driver is changed. Calling the notifier change allows potential users of the interface know about this planned change, and even block it. After the change has occurred, send a second notification to users can evaluate the new device type etc. Signed-off-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
120 lines
3.4 KiB
C
120 lines
3.4 KiB
C
/*
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* Generic HDLC support routines for Linux
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*
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* Copyright (C) 1999-2005 Krzysztof Halasa <khc@pm.waw.pl>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2 of the GNU General Public License
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* as published by the Free Software Foundation.
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*/
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#ifndef __HDLC_H
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#define __HDLC_H
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/hdlc/ioctl.h>
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#include <uapi/linux/hdlc.h>
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/* This structure is a private property of HDLC protocols.
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Hardware drivers have no interest here */
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struct hdlc_proto {
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int (*open)(struct net_device *dev);
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void (*close)(struct net_device *dev);
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void (*start)(struct net_device *dev); /* if open & DCD */
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void (*stop)(struct net_device *dev); /* if open & !DCD */
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void (*detach)(struct net_device *dev);
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int (*ioctl)(struct net_device *dev, struct ifreq *ifr);
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__be16 (*type_trans)(struct sk_buff *skb, struct net_device *dev);
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int (*netif_rx)(struct sk_buff *skb);
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netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
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struct module *module;
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struct hdlc_proto *next; /* next protocol in the list */
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};
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/* Pointed to by netdev_priv(dev) */
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typedef struct hdlc_device {
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/* used by HDLC layer to take control over HDLC device from hw driver*/
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int (*attach)(struct net_device *dev,
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unsigned short encoding, unsigned short parity);
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/* hardware driver must handle this instead of dev->hard_start_xmit */
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netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
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/* Things below are for HDLC layer internal use only */
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const struct hdlc_proto *proto;
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int carrier;
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int open;
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spinlock_t state_lock;
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void *state;
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void *priv;
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} hdlc_device;
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/* Exported from hdlc module */
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/* Called by hardware driver when a user requests HDLC service */
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int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
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/* Must be used by hardware driver on module startup/exit */
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#define register_hdlc_device(dev) register_netdev(dev)
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void unregister_hdlc_device(struct net_device *dev);
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void register_hdlc_protocol(struct hdlc_proto *proto);
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void unregister_hdlc_protocol(struct hdlc_proto *proto);
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struct net_device *alloc_hdlcdev(void *priv);
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static inline struct hdlc_device* dev_to_hdlc(struct net_device *dev)
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{
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return netdev_priv(dev);
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}
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static __inline__ void debug_frame(const struct sk_buff *skb)
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{
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int i;
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for (i=0; i < skb->len; i++) {
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if (i == 100) {
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printk("...\n");
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return;
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}
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printk(" %02X", skb->data[i]);
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}
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printk("\n");
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}
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/* Must be called by hardware driver when HDLC device is being opened */
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int hdlc_open(struct net_device *dev);
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/* Must be called by hardware driver when HDLC device is being closed */
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void hdlc_close(struct net_device *dev);
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/* May be used by hardware driver */
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int hdlc_change_mtu(struct net_device *dev, int new_mtu);
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/* Must be pointed to by hw driver's dev->netdev_ops->ndo_start_xmit */
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netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev);
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int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
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size_t size);
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/* May be used by hardware driver to gain control over HDLC device */
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int detach_hdlc_protocol(struct net_device *dev);
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static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
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struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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skb->dev = dev;
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skb_reset_mac_header(skb);
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if (hdlc->proto->type_trans)
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return hdlc->proto->type_trans(skb, dev);
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else
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return htons(ETH_P_HDLC);
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}
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#endif /* __HDLC_H */
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