2 * Generic HDLC support routines for Linux
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of version 2 of the GNU General Public License
8 * as published by the Free Software Foundation.
10 * Currently supported:
13 * * Frame Relay with ANSI or CCITT LMI (both user and network side)
17 * Use sethdlc utility to set line parameters, protocol and PVCs
20 * - proto->open(), close(), start(), stop() calls are serialized.
21 * The order is: open, [ start, stop ... ] close ...
22 * - proto->start() and stop() are called with spin_lock_irq held.
25 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27 #include <linux/errno.h>
28 #include <linux/hdlc.h>
29 #include <linux/if_arp.h>
30 #include <linux/inetdevice.h>
31 #include <linux/init.h>
32 #include <linux/kernel.h>
33 #include <linux/module.h>
34 #include <linux/notifier.h>
35 #include <linux/pkt_sched.h>
36 #include <linux/poll.h>
37 #include <linux/rtnetlink.h>
38 #include <linux/skbuff.h>
39 #include <linux/slab.h>
40 #include <net/net_namespace.h>
43 static const char* version = "HDLC support module revision 1.22";
47 static struct hdlc_proto *first_proto;
49 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
50 struct packet_type *p, struct net_device *orig_dev)
52 struct hdlc_device *hdlc = dev_to_hdlc(dev);
54 if (!net_eq(dev_net(dev), &init_net)) {
59 BUG_ON(!hdlc->proto->netif_rx);
60 return hdlc->proto->netif_rx(skb);
63 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
65 hdlc_device *hdlc = dev_to_hdlc(dev);
67 if (hdlc->proto->xmit)
68 return hdlc->proto->xmit(skb, dev);
70 return hdlc->xmit(skb, dev); /* call hardware driver directly */
73 static inline void hdlc_proto_start(struct net_device *dev)
75 hdlc_device *hdlc = dev_to_hdlc(dev);
76 if (hdlc->proto->start)
77 hdlc->proto->start(dev);
82 static inline void hdlc_proto_stop(struct net_device *dev)
84 hdlc_device *hdlc = dev_to_hdlc(dev);
85 if (hdlc->proto->stop)
86 hdlc->proto->stop(dev);
91 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
94 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
99 if (!net_eq(dev_net(dev), &init_net))
102 if (!(dev->priv_flags & IFF_WAN_HDLC))
103 return NOTIFY_DONE; /* not an HDLC device */
105 if (event != NETDEV_CHANGE)
106 return NOTIFY_DONE; /* Only interested in carrier changes */
108 on = netif_carrier_ok(dev);
111 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
115 hdlc = dev_to_hdlc(dev);
116 spin_lock_irqsave(&hdlc->state_lock, flags);
118 if (hdlc->carrier == on)
119 goto carrier_exit; /* no change in DCD line level */
127 netdev_info(dev, "Carrier detected\n");
128 hdlc_proto_start(dev);
130 netdev_info(dev, "Carrier lost\n");
131 hdlc_proto_stop(dev);
135 spin_unlock_irqrestore(&hdlc->state_lock, flags);
141 /* Must be called by hardware driver when HDLC device is being opened */
142 int hdlc_open(struct net_device *dev)
144 hdlc_device *hdlc = dev_to_hdlc(dev);
146 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
147 hdlc->carrier, hdlc->open);
150 if (hdlc->proto == NULL)
151 return -ENOSYS; /* no protocol attached */
153 if (hdlc->proto->open) {
154 int result = hdlc->proto->open(dev);
159 spin_lock_irq(&hdlc->state_lock);
162 netdev_info(dev, "Carrier detected\n");
163 hdlc_proto_start(dev);
165 netdev_info(dev, "No carrier\n");
169 spin_unlock_irq(&hdlc->state_lock);
175 /* Must be called by hardware driver when HDLC device is being closed */
176 void hdlc_close(struct net_device *dev)
178 hdlc_device *hdlc = dev_to_hdlc(dev);
180 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
181 hdlc->carrier, hdlc->open);
184 spin_lock_irq(&hdlc->state_lock);
188 hdlc_proto_stop(dev);
190 spin_unlock_irq(&hdlc->state_lock);
192 if (hdlc->proto->close)
193 hdlc->proto->close(dev);
198 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
200 struct hdlc_proto *proto = first_proto;
203 if (cmd != SIOCWANDEV)
206 if (dev_to_hdlc(dev)->proto) {
207 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
208 if (result != -EINVAL)
212 /* Not handled by currently attached protocol (if any) */
215 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
222 static const struct header_ops hdlc_null_ops;
224 static void hdlc_setup_dev(struct net_device *dev)
226 /* Re-init all variables changed by HDLC protocol drivers,
227 * including ether_setup() called from hdlc_raw_eth.c.
229 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
230 dev->priv_flags = IFF_WAN_HDLC;
231 dev->mtu = HDLC_MAX_MTU;
233 dev->max_mtu = HDLC_MAX_MTU;
234 dev->type = ARPHRD_RAWHDLC;
235 dev->hard_header_len = 16;
237 dev->header_ops = &hdlc_null_ops;
240 static void hdlc_setup(struct net_device *dev)
242 hdlc_device *hdlc = dev_to_hdlc(dev);
247 spin_lock_init(&hdlc->state_lock);
250 struct net_device *alloc_hdlcdev(void *priv)
252 struct net_device *dev;
253 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
254 NET_NAME_UNKNOWN, hdlc_setup);
256 dev_to_hdlc(dev)->priv = priv;
260 void unregister_hdlc_device(struct net_device *dev)
263 detach_hdlc_protocol(dev);
264 unregister_netdevice(dev);
270 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
275 err = detach_hdlc_protocol(dev);
279 if (!try_module_get(proto->module))
283 dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
284 if (dev_to_hdlc(dev)->state == NULL) {
285 module_put(proto->module);
289 dev_to_hdlc(dev)->proto = proto;
295 int detach_hdlc_protocol(struct net_device *dev)
297 hdlc_device *hdlc = dev_to_hdlc(dev);
301 err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
302 err = notifier_to_errno(err);
304 netdev_err(dev, "Refused to change device type\n");
308 if (hdlc->proto->detach)
309 hdlc->proto->detach(dev);
310 module_put(hdlc->proto->module);
321 void register_hdlc_protocol(struct hdlc_proto *proto)
324 proto->next = first_proto;
330 void unregister_hdlc_protocol(struct hdlc_proto *proto)
332 struct hdlc_proto **p;
336 while (*p != proto) {
347 MODULE_DESCRIPTION("HDLC support module");
348 MODULE_LICENSE("GPL v2");
350 EXPORT_SYMBOL(hdlc_start_xmit);
351 EXPORT_SYMBOL(hdlc_open);
352 EXPORT_SYMBOL(hdlc_close);
353 EXPORT_SYMBOL(hdlc_ioctl);
354 EXPORT_SYMBOL(alloc_hdlcdev);
355 EXPORT_SYMBOL(unregister_hdlc_device);
356 EXPORT_SYMBOL(register_hdlc_protocol);
357 EXPORT_SYMBOL(unregister_hdlc_protocol);
358 EXPORT_SYMBOL(attach_hdlc_protocol);
359 EXPORT_SYMBOL(detach_hdlc_protocol);
361 static struct packet_type hdlc_packet_type __read_mostly = {
362 .type = cpu_to_be16(ETH_P_HDLC),
367 static struct notifier_block hdlc_notifier = {
368 .notifier_call = hdlc_device_event,
372 static int __init hdlc_module_init(void)
376 pr_info("%s\n", version);
377 if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
379 dev_add_pack(&hdlc_packet_type);
385 static void __exit hdlc_module_exit(void)
387 dev_remove_pack(&hdlc_packet_type);
388 unregister_netdevice_notifier(&hdlc_notifier);
392 module_init(hdlc_module_init);
393 module_exit(hdlc_module_exit);