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379 lines
8.1 KiB
379 lines
8.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Generic HDLC support routines for Linux |
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* |
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* Copyright (C) 1999 - 2008 Krzysztof Halasa <[email protected]> |
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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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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; |
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/* First make sure "dev" is an HDLC device */ |
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if (!(dev->priv_flags & IFF_WAN_HDLC)) { |
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kfree_skb(skb); |
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return NET_RX_SUCCESS; |
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} |
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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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EXPORT_SYMBOL(hdlc_start_xmit); |
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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 = netdev_notifier_info_to_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) |
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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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} |
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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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EXPORT_SYMBOL(hdlc_open); |
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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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EXPORT_SYMBOL(hdlc_close); |
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int hdlc_ioctl(struct net_device *dev, struct if_settings *ifs) |
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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 (dev_to_hdlc(dev)->proto) { |
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result = dev_to_hdlc(dev)->proto->ioctl(dev, ifs); |
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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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result = proto->ioctl(dev, ifs); |
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if (result != -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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EXPORT_SYMBOL(hdlc_ioctl); |
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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->min_mtu = 68; |
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dev->max_mtu = HDLC_MAX_MTU; |
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dev->type = ARPHRD_RAWHDLC; |
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dev->hard_header_len = 0; |
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dev->needed_headroom = 0; |
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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", |
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NET_NAME_UNKNOWN, 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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EXPORT_SYMBOL(alloc_hdlcdev); |
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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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detach_hdlc_protocol(dev); |
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unregister_netdevice(dev); |
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rtnl_unlock(); |
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} |
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EXPORT_SYMBOL(unregister_hdlc_device); |
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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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int err; |
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err = detach_hdlc_protocol(dev); |
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if (err) |
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return err; |
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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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dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL); |
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if (!dev_to_hdlc(dev)->state) { |
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module_put(proto->module); |
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return -ENOBUFS; |
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} |
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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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EXPORT_SYMBOL(attach_hdlc_protocol); |
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int 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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int err; |
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if (hdlc->proto) { |
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err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev); |
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err = notifier_to_errno(err); |
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if (err) { |
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netdev_err(dev, "Refused to change device type\n"); |
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return err; |
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} |
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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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return 0; |
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} |
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EXPORT_SYMBOL(detach_hdlc_protocol); |
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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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EXPORT_SYMBOL(register_hdlc_protocol); |
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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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EXPORT_SYMBOL(unregister_hdlc_protocol); |
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MODULE_AUTHOR("Krzysztof Halasa <[email protected]>"); |
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MODULE_DESCRIPTION("HDLC support module"); |
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MODULE_LICENSE("GPL v2"); |
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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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result = register_netdevice_notifier(&hdlc_notifier); |
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if (result) |
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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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