2 * Generic HDLC support routines for Linux
4 * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
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 int hdlc_change_mtu(struct net_device *dev, int new_mtu)
51 if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
57 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
58 struct packet_type *p, struct net_device *orig_dev)
60 struct hdlc_device *hdlc;
62 /* First make sure "dev" is an HDLC device */
63 if (!(dev->priv_flags & IFF_WAN_HDLC)) {
65 return NET_RX_SUCCESS;
68 hdlc = dev_to_hdlc(dev);
70 if (!net_eq(dev_net(dev), &init_net)) {
75 BUG_ON(!hdlc->proto->netif_rx);
76 return hdlc->proto->netif_rx(skb);
79 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev)
81 hdlc_device *hdlc = dev_to_hdlc(dev);
83 if (hdlc->proto->xmit)
84 return hdlc->proto->xmit(skb, dev);
86 return hdlc->xmit(skb, dev); /* call hardware driver directly */
89 static inline void hdlc_proto_start(struct net_device *dev)
91 hdlc_device *hdlc = dev_to_hdlc(dev);
92 if (hdlc->proto->start)
93 hdlc->proto->start(dev);
98 static inline void hdlc_proto_stop(struct net_device *dev)
100 hdlc_device *hdlc = dev_to_hdlc(dev);
101 if (hdlc->proto->stop)
102 hdlc->proto->stop(dev);
107 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
110 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
115 if (!net_eq(dev_net(dev), &init_net))
118 if (!(dev->priv_flags & IFF_WAN_HDLC))
119 return NOTIFY_DONE; /* not an HDLC device */
121 if (event != NETDEV_CHANGE)
122 return NOTIFY_DONE; /* Only interested in carrier changes */
124 on = netif_carrier_ok(dev);
127 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
131 hdlc = dev_to_hdlc(dev);
132 spin_lock_irqsave(&hdlc->state_lock, flags);
134 if (hdlc->carrier == on)
135 goto carrier_exit; /* no change in DCD line level */
143 netdev_info(dev, "Carrier detected\n");
144 hdlc_proto_start(dev);
146 netdev_info(dev, "Carrier lost\n");
147 hdlc_proto_stop(dev);
151 spin_unlock_irqrestore(&hdlc->state_lock, flags);
157 /* Must be called by hardware driver when HDLC device is being opened */
158 int hdlc_open(struct net_device *dev)
160 hdlc_device *hdlc = dev_to_hdlc(dev);
162 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
163 hdlc->carrier, hdlc->open);
166 if (hdlc->proto == NULL)
167 return -ENOSYS; /* no protocol attached */
169 if (hdlc->proto->open) {
170 int result = hdlc->proto->open(dev);
175 spin_lock_irq(&hdlc->state_lock);
178 netdev_info(dev, "Carrier detected\n");
179 hdlc_proto_start(dev);
181 netdev_info(dev, "No carrier\n");
185 spin_unlock_irq(&hdlc->state_lock);
191 /* Must be called by hardware driver when HDLC device is being closed */
192 void hdlc_close(struct net_device *dev)
194 hdlc_device *hdlc = dev_to_hdlc(dev);
196 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
197 hdlc->carrier, hdlc->open);
200 spin_lock_irq(&hdlc->state_lock);
204 hdlc_proto_stop(dev);
206 spin_unlock_irq(&hdlc->state_lock);
208 if (hdlc->proto->close)
209 hdlc->proto->close(dev);
214 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
216 struct hdlc_proto *proto = first_proto;
219 if (cmd != SIOCWANDEV)
222 if (dev_to_hdlc(dev)->proto) {
223 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
224 if (result != -EINVAL)
228 /* Not handled by currently attached protocol (if any) */
231 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
238 static const struct header_ops hdlc_null_ops;
240 static void hdlc_setup_dev(struct net_device *dev)
242 /* Re-init all variables changed by HDLC protocol drivers,
243 * including ether_setup() called from hdlc_raw_eth.c.
245 dev->flags = IFF_POINTOPOINT | IFF_NOARP;
246 dev->priv_flags = IFF_WAN_HDLC;
247 dev->mtu = HDLC_MAX_MTU;
248 dev->type = ARPHRD_RAWHDLC;
249 dev->hard_header_len = 16;
251 dev->header_ops = &hdlc_null_ops;
254 static void hdlc_setup(struct net_device *dev)
256 hdlc_device *hdlc = dev_to_hdlc(dev);
261 spin_lock_init(&hdlc->state_lock);
264 struct net_device *alloc_hdlcdev(void *priv)
266 struct net_device *dev;
267 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d",
268 NET_NAME_UNKNOWN, hdlc_setup);
270 dev_to_hdlc(dev)->priv = priv;
274 void unregister_hdlc_device(struct net_device *dev)
277 unregister_netdevice(dev);
278 detach_hdlc_protocol(dev);
284 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
287 detach_hdlc_protocol(dev);
289 if (!try_module_get(proto->module))
293 dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL);
294 if (dev_to_hdlc(dev)->state == NULL) {
295 module_put(proto->module);
299 dev_to_hdlc(dev)->proto = proto;
304 void detach_hdlc_protocol(struct net_device *dev)
306 hdlc_device *hdlc = dev_to_hdlc(dev);
309 if (hdlc->proto->detach)
310 hdlc->proto->detach(dev);
311 module_put(hdlc->proto->module);
320 void register_hdlc_protocol(struct hdlc_proto *proto)
323 proto->next = first_proto;
329 void unregister_hdlc_protocol(struct hdlc_proto *proto)
331 struct hdlc_proto **p;
335 while (*p != proto) {
345 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
346 MODULE_DESCRIPTION("HDLC support module");
347 MODULE_LICENSE("GPL v2");
349 EXPORT_SYMBOL(hdlc_change_mtu);
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);