mirror of https://gitee.com/openkylin/linux.git
386 lines
8.1 KiB
C
386 lines
8.1 KiB
C
/*
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* Generic HDLC support routines for Linux
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*
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* Copyright (C) 1999 - 2008 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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* Currently supported:
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* * raw IP-in-HDLC
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* * Cisco HDLC
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* * Frame Relay with ANSI or CCITT LMI (both user and network side)
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* * PPP
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* * X.25
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*
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* Use sethdlc utility to set line parameters, protocol and PVCs
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*
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* How does it work:
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* - proto->open(), close(), start(), stop() calls are serialized.
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* The order is: open, [ start, stop ... ] close ...
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* - proto->start() and stop() are called with spin_lock_irq held.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/errno.h>
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#include <linux/hdlc.h>
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#include <linux/if_arp.h>
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#include <linux/inetdevice.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/notifier.h>
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#include <linux/pkt_sched.h>
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#include <linux/poll.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <linux/slab.h>
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#include <net/net_namespace.h>
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static const char* version = "HDLC support module revision 1.22";
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#undef DEBUG_LINK
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static struct hdlc_proto *first_proto;
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int hdlc_change_mtu(struct net_device *dev, int new_mtu)
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{
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if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
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return -EINVAL;
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dev->mtu = new_mtu;
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return 0;
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}
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static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
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struct packet_type *p, struct net_device *orig_dev)
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{
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struct hdlc_device *hdlc = dev_to_hdlc(dev);
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if (!net_eq(dev_net(dev), &init_net)) {
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kfree_skb(skb);
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return 0;
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}
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BUG_ON(!hdlc->proto->netif_rx);
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return hdlc->proto->netif_rx(skb);
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}
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netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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if (hdlc->proto->xmit)
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return hdlc->proto->xmit(skb, dev);
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return hdlc->xmit(skb, dev); /* call hardware driver directly */
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}
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static inline void hdlc_proto_start(struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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if (hdlc->proto->start)
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hdlc->proto->start(dev);
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}
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static inline void hdlc_proto_stop(struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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if (hdlc->proto->stop)
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hdlc->proto->stop(dev);
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}
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static int hdlc_device_event(struct notifier_block *this, unsigned long event,
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void *ptr)
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{
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struct net_device *dev = ptr;
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hdlc_device *hdlc;
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unsigned long flags;
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int on;
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if (!net_eq(dev_net(dev), &init_net))
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return NOTIFY_DONE;
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if (!(dev->priv_flags & IFF_WAN_HDLC))
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return NOTIFY_DONE; /* not an HDLC device */
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if (event != NETDEV_CHANGE)
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return NOTIFY_DONE; /* Only interested in carrier changes */
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on = netif_carrier_ok(dev);
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#ifdef DEBUG_LINK
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printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
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dev->name, on);
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#endif
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hdlc = dev_to_hdlc(dev);
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spin_lock_irqsave(&hdlc->state_lock, flags);
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if (hdlc->carrier == on)
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goto carrier_exit; /* no change in DCD line level */
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hdlc->carrier = on;
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if (!hdlc->open)
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goto carrier_exit;
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if (hdlc->carrier) {
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netdev_info(dev, "Carrier detected\n");
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hdlc_proto_start(dev);
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} else {
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netdev_info(dev, "Carrier lost\n");
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hdlc_proto_stop(dev);
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}
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carrier_exit:
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spin_unlock_irqrestore(&hdlc->state_lock, flags);
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return NOTIFY_DONE;
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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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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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#ifdef DEBUG_LINK
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printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
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hdlc->carrier, hdlc->open);
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#endif
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if (hdlc->proto == NULL)
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return -ENOSYS; /* no protocol attached */
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if (hdlc->proto->open) {
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int result = hdlc->proto->open(dev);
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if (result)
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return result;
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}
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spin_lock_irq(&hdlc->state_lock);
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if (hdlc->carrier) {
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netdev_info(dev, "Carrier detected\n");
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hdlc_proto_start(dev);
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} else
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netdev_info(dev, "No carrier\n");
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hdlc->open = 1;
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spin_unlock_irq(&hdlc->state_lock);
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return 0;
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}
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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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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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#ifdef DEBUG_LINK
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printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
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hdlc->carrier, hdlc->open);
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#endif
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spin_lock_irq(&hdlc->state_lock);
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hdlc->open = 0;
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if (hdlc->carrier)
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hdlc_proto_stop(dev);
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spin_unlock_irq(&hdlc->state_lock);
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if (hdlc->proto->close)
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hdlc->proto->close(dev);
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}
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int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
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{
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struct hdlc_proto *proto = first_proto;
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int result;
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if (cmd != SIOCWANDEV)
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return -EINVAL;
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if (dev_to_hdlc(dev)->proto) {
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result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
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if (result != -EINVAL)
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return result;
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}
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/* Not handled by currently attached protocol (if any) */
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while (proto) {
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if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
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return result;
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proto = proto->next;
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}
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return -EINVAL;
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}
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static const struct header_ops hdlc_null_ops;
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static void hdlc_setup_dev(struct net_device *dev)
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{
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/* Re-init all variables changed by HDLC protocol drivers,
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* including ether_setup() called from hdlc_raw_eth.c.
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*/
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dev->flags = IFF_POINTOPOINT | IFF_NOARP;
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dev->priv_flags = IFF_WAN_HDLC;
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dev->mtu = HDLC_MAX_MTU;
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dev->type = ARPHRD_RAWHDLC;
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dev->hard_header_len = 16;
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dev->addr_len = 0;
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dev->header_ops = &hdlc_null_ops;
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}
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static void hdlc_setup(struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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hdlc_setup_dev(dev);
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hdlc->carrier = 1;
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hdlc->open = 0;
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spin_lock_init(&hdlc->state_lock);
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}
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struct net_device *alloc_hdlcdev(void *priv)
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{
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struct net_device *dev;
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dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d", hdlc_setup);
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if (dev)
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dev_to_hdlc(dev)->priv = priv;
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return dev;
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}
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void unregister_hdlc_device(struct net_device *dev)
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{
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rtnl_lock();
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unregister_netdevice(dev);
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detach_hdlc_protocol(dev);
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rtnl_unlock();
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}
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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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{
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detach_hdlc_protocol(dev);
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if (!try_module_get(proto->module))
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return -ENOSYS;
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if (size)
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if ((dev_to_hdlc(dev)->state = kmalloc(size,
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GFP_KERNEL)) == NULL) {
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netdev_warn(dev,
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"Memory squeeze on hdlc_proto_attach()\n");
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module_put(proto->module);
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return -ENOBUFS;
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}
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dev_to_hdlc(dev)->proto = proto;
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return 0;
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}
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void detach_hdlc_protocol(struct net_device *dev)
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{
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hdlc_device *hdlc = dev_to_hdlc(dev);
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if (hdlc->proto) {
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if (hdlc->proto->detach)
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hdlc->proto->detach(dev);
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module_put(hdlc->proto->module);
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hdlc->proto = NULL;
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}
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kfree(hdlc->state);
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hdlc->state = NULL;
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hdlc_setup_dev(dev);
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}
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void register_hdlc_protocol(struct hdlc_proto *proto)
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{
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rtnl_lock();
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proto->next = first_proto;
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first_proto = proto;
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rtnl_unlock();
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}
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void unregister_hdlc_protocol(struct hdlc_proto *proto)
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{
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struct hdlc_proto **p;
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rtnl_lock();
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p = &first_proto;
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while (*p != proto) {
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BUG_ON(!*p);
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p = &((*p)->next);
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}
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*p = proto->next;
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rtnl_unlock();
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}
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MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
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MODULE_DESCRIPTION("HDLC support module");
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MODULE_LICENSE("GPL v2");
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EXPORT_SYMBOL(hdlc_change_mtu);
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EXPORT_SYMBOL(hdlc_start_xmit);
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EXPORT_SYMBOL(hdlc_open);
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EXPORT_SYMBOL(hdlc_close);
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EXPORT_SYMBOL(hdlc_ioctl);
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EXPORT_SYMBOL(alloc_hdlcdev);
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EXPORT_SYMBOL(unregister_hdlc_device);
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EXPORT_SYMBOL(register_hdlc_protocol);
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EXPORT_SYMBOL(unregister_hdlc_protocol);
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EXPORT_SYMBOL(attach_hdlc_protocol);
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EXPORT_SYMBOL(detach_hdlc_protocol);
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static struct packet_type hdlc_packet_type __read_mostly = {
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.type = cpu_to_be16(ETH_P_HDLC),
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.func = hdlc_rcv,
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};
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static struct notifier_block hdlc_notifier = {
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.notifier_call = hdlc_device_event,
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};
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static int __init hdlc_module_init(void)
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{
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int result;
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pr_info("%s\n", version);
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if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
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return result;
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dev_add_pack(&hdlc_packet_type);
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return 0;
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}
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static void __exit hdlc_module_exit(void)
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{
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dev_remove_pack(&hdlc_packet_type);
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unregister_netdevice_notifier(&hdlc_notifier);
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}
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module_init(hdlc_module_init);
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module_exit(hdlc_module_exit);
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