1 // SPDX-License-Identifier: GPL-2.0-only
3 * Generic HDLC support routines for Linux
5 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
10 * * Frame Relay with ANSI or CCITT LMI (both user and network side)
14 * Use sethdlc utility to set line parameters, protocol and PVCs
17 * - proto->open(), close(), start(), stop() calls are serialized.
18 * The order is: open, [ start, stop ... ] close ...
19 * - proto->start() and stop() are called with spin_lock_irq held.
22 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 #include <linux/errno.h>
25 #include <linux/hdlc.h>
26 #include <linux/if_arp.h>
27 #include <linux/inetdevice.h>
28 #include <linux/init.h>
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/notifier.h>
32 #include <linux/pkt_sched.h>
33 #include <linux/poll.h>
34 #include <linux/rtnetlink.h>
35 #include <linux/skbuff.h>
36 #include <linux/slab.h>
37 #include <net/net_namespace.h>
40 static const char* version = "HDLC support module revision 1.22";
44 static struct hdlc_proto *first_proto;
46 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
47 struct packet_type *p, struct net_device *orig_dev)
49 struct hdlc_device *hdlc = dev_to_hdlc(dev);
51 if (!net_eq(dev_net(dev), &init_net)) {
56 BUG_ON(!hdlc->proto->netif_rx);
57 return hdlc->proto->netif_rx(skb);
60 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
62 hdlc_device *hdlc = dev_to_hdlc(dev);
64 if (hdlc->proto->xmit)
65 return hdlc->proto->xmit(skb, dev);
67 return hdlc->xmit(skb, dev); /* call hardware driver directly */
70 static inline void hdlc_proto_start(struct net_device *dev)
72 hdlc_device *hdlc = dev_to_hdlc(dev);
73 if (hdlc->proto->start)
74 hdlc->proto->start(dev);
79 static inline void hdlc_proto_stop(struct net_device *dev)
81 hdlc_device *hdlc = dev_to_hdlc(dev);
82 if (hdlc->proto->stop)
83 hdlc->proto->stop(dev);
88 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
91 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
96 if (!net_eq(dev_net(dev), &init_net))
99 if (!(dev->priv_flags & IFF_WAN_HDLC))
100 return NOTIFY_DONE; /* not an HDLC device */
102 if (event != NETDEV_CHANGE)
103 return NOTIFY_DONE; /* Only interested in carrier changes */
105 on = netif_carrier_ok(dev);
108 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
112 hdlc = dev_to_hdlc(dev);
113 spin_lock_irqsave(&hdlc->state_lock, flags);
115 if (hdlc->carrier == on)
116 goto carrier_exit; /* no change in DCD line level */
124 netdev_info(dev, "Carrier detected\n");
125 hdlc_proto_start(dev);
127 netdev_info(dev, "Carrier lost\n");
128 hdlc_proto_stop(dev);
132 spin_unlock_irqrestore(&hdlc->state_lock, flags);
138 /* Must be called by hardware driver when HDLC device is being opened */
139 int hdlc_open(struct net_device *dev)
141 hdlc_device *hdlc = dev_to_hdlc(dev);
143 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
144 hdlc->carrier, hdlc->open);
147 if (hdlc->proto == NULL)
148 return -ENOSYS; /* no protocol attached */
150 if (hdlc->proto->open) {
151 int result = hdlc->proto->open(dev);
156 spin_lock_irq(&hdlc->state_lock);
159 netdev_info(dev, "Carrier detected\n");
160 hdlc_proto_start(dev);
162 netdev_info(dev, "No carrier\n");
166 spin_unlock_irq(&hdlc->state_lock);
172 /* Must be called by hardware driver when HDLC device is being closed */
173 void hdlc_close(struct net_device *dev)
175 hdlc_device *hdlc = dev_to_hdlc(dev);
177 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
178 hdlc->carrier, hdlc->open);
181 spin_lock_irq(&hdlc->state_lock);
185 hdlc_proto_stop(dev);
187 spin_unlock_irq(&hdlc->state_lock);
189 if (hdlc->proto->close)
190 hdlc->proto->close(dev);
195 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
197 struct hdlc_proto *proto = first_proto;
200 if (cmd != SIOCWANDEV)
203 if (dev_to_hdlc(dev)->proto) {
204 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
205 if (result != -EINVAL)
209 /* Not handled by currently attached protocol (if any) */
212 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
219 static const struct header_ops hdlc_null_ops;
221 static void hdlc_setup_dev(struct net_device *dev)
223 /* Re-init all variables changed by HDLC protocol drivers,
224 * including ether_setup() called from hdlc_raw_eth.c.
226 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
227 dev->priv_flags = IFF_WAN_HDLC;
228 dev->mtu = HDLC_MAX_MTU;
230 dev->max_mtu = HDLC_MAX_MTU;
231 dev->type = ARPHRD_RAWHDLC;
232 dev->hard_header_len = 16;
233 dev->needed_headroom = 0;
235 dev->header_ops = &hdlc_null_ops;
238 static void hdlc_setup(struct net_device *dev)
240 hdlc_device *hdlc = dev_to_hdlc(dev);
245 spin_lock_init(&hdlc->state_lock);
248 struct net_device *alloc_hdlcdev(void *priv)
250 struct net_device *dev;
251 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
252 NET_NAME_UNKNOWN, hdlc_setup);
254 dev_to_hdlc(dev)->priv = priv;
258 void unregister_hdlc_device(struct net_device *dev)
261 detach_hdlc_protocol(dev);
262 unregister_netdevice(dev);
268 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
273 err = detach_hdlc_protocol(dev);
277 if (!try_module_get(proto->module))
281 dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
282 if (dev_to_hdlc(dev)->state == NULL) {
283 module_put(proto->module);
287 dev_to_hdlc(dev)->proto = proto;
293 int detach_hdlc_protocol(struct net_device *dev)
295 hdlc_device *hdlc = dev_to_hdlc(dev);
299 err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev);
300 err = notifier_to_errno(err);
302 netdev_err(dev, "Refused to change device type\n");
306 if (hdlc->proto->detach)
307 hdlc->proto->detach(dev);
308 module_put(hdlc->proto->module);
319 void register_hdlc_protocol(struct hdlc_proto *proto)
322 proto->next = first_proto;
328 void unregister_hdlc_protocol(struct hdlc_proto *proto)
330 struct hdlc_proto **p;
334 while (*p != proto) {
344 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
345 MODULE_DESCRIPTION("HDLC support module");
346 MODULE_LICENSE("GPL v2");
348 EXPORT_SYMBOL(hdlc_start_xmit);
349 EXPORT_SYMBOL(hdlc_open);
350 EXPORT_SYMBOL(hdlc_close);
351 EXPORT_SYMBOL(hdlc_ioctl);
352 EXPORT_SYMBOL(alloc_hdlcdev);
353 EXPORT_SYMBOL(unregister_hdlc_device);
354 EXPORT_SYMBOL(register_hdlc_protocol);
355 EXPORT_SYMBOL(unregister_hdlc_protocol);
356 EXPORT_SYMBOL(attach_hdlc_protocol);
357 EXPORT_SYMBOL(detach_hdlc_protocol);
359 static struct packet_type hdlc_packet_type __read_mostly = {
360 .type = cpu_to_be16(ETH_P_HDLC),
365 static struct notifier_block hdlc_notifier = {
366 .notifier_call = hdlc_device_event,
370 static int __init hdlc_module_init(void)
374 pr_info("%s\n", version);
375 if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
377 dev_add_pack(&hdlc_packet_type);
383 static void __exit hdlc_module_exit(void)
385 dev_remove_pack(&hdlc_packet_type);
386 unregister_netdevice_notifier(&hdlc_notifier);
390 module_init(hdlc_module_init);
391 module_exit(hdlc_module_exit);