git.oblomov.eu Git - linux-2.6/blob - drivers/net/wan/hdlc.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  *
   4  * Copyright (C) 1999 - 2008 Krzysztof Halasa <khc@pm.waw.pl>
   5  *
   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.
   9  *
  10  * Currently supported:
  11  *      * raw IP-in-HDLC
  12  *      * Cisco HDLC
  13  *      * Frame Relay with ANSI or CCITT LMI (both user and network side)
  14  *      * PPP
  15  *      * X.25
  16  *
  17  * Use sethdlc utility to set line parameters, protocol and PVCs
  18  *
  19  * How does it work:
  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.
  23  */
  24
  25 #include <linux/errno.h>
  26 #include <linux/hdlc.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/inetdevice.h>
  29 #include <linux/init.h>
  30 #include <linux/kernel.h>
  31 #include <linux/module.h>
  32 #include <linux/notifier.h>
  33 #include <linux/pkt_sched.h>
  34 #include <linux/poll.h>
  35 #include <linux/rtnetlink.h>
  36 #include <linux/skbuff.h>
  37 #include <linux/slab.h>
  38 #include <net/net_namespace.h>
  39
  40
  41 static const char* version = "HDLC support module revision 1.22";
  42
  43 #undef DEBUG_LINK
  44
  45 static struct hdlc_proto *first_proto;
  46
  47 static int hdlc_change_mtu(struct net_device *dev, int new_mtu)
  48 {
  49         if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
  50                 return -EINVAL;
  51         dev->mtu = new_mtu;
  52         return 0;
  53 }
  54
  55 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
  56                     struct packet_type *p, struct net_device *orig_dev)
  57 {
  58         struct hdlc_device *hdlc = dev_to_hdlc(dev);
  59
  60         if (dev_net(dev) != &init_net) {
  61                 kfree_skb(skb);
  62                 return 0;
  63         }
  64
  65         BUG_ON(!hdlc->proto->netif_rx);
  66         return hdlc->proto->netif_rx(skb);
  67 }
  68
  69
  70
  71 static inline void hdlc_proto_start(struct net_device *dev)
  72 {
  73         hdlc_device *hdlc = dev_to_hdlc(dev);
  74         if (hdlc->proto->start)
  75                 hdlc->proto->start(dev);
  76 }
  77
  78
  79
  80 static inline void hdlc_proto_stop(struct net_device *dev)
  81 {
  82         hdlc_device *hdlc = dev_to_hdlc(dev);
  83         if (hdlc->proto->stop)
  84                 hdlc->proto->stop(dev);
  85 }
  86
  87
  88
  89 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
  90                              void *ptr)
  91 {
  92         struct net_device *dev = ptr;
  93         hdlc_device *hdlc;
  94         unsigned long flags;
  95         int on;
  96
  97         if (dev_net(dev) != &init_net)
  98                 return NOTIFY_DONE;
  99
 100         if (!(dev->priv_flags & IFF_WAN_HDLC))
 101                 return NOTIFY_DONE; /* not an HDLC device */
 102
 103         if (event != NETDEV_CHANGE)
 104                 return NOTIFY_DONE; /* Only interrested in carrier changes */
 105
 106         on = netif_carrier_ok(dev);
 107
 108 #ifdef DEBUG_LINK
 109         printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
 110                dev->name, on);
 111 #endif
 112
 113         hdlc = dev_to_hdlc(dev);
 114         spin_lock_irqsave(&hdlc->state_lock, flags);
 115
 116         if (hdlc->carrier == on)
 117                 goto carrier_exit; /* no change in DCD line level */
 118
 119         hdlc->carrier = on;
 120
 121         if (!hdlc->open)
 122                 goto carrier_exit;
 123
 124         if (hdlc->carrier) {
 125                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 126                 hdlc_proto_start(dev);
 127         } else {
 128                 printk(KERN_INFO "%s: Carrier lost\n", dev->name);
 129                 hdlc_proto_stop(dev);
 130         }
 131
 132 carrier_exit:
 133         spin_unlock_irqrestore(&hdlc->state_lock, flags);
 134         return NOTIFY_DONE;
 135 }
 136
 137
 138
 139 /* Must be called by hardware driver when HDLC device is being opened */
 140 int hdlc_open(struct net_device *dev)
 141 {
 142         hdlc_device *hdlc = dev_to_hdlc(dev);
 143 #ifdef DEBUG_LINK
 144         printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
 145                hdlc->carrier, hdlc->open);
 146 #endif
 147
 148         if (hdlc->proto == NULL)
 149                 return -ENOSYS; /* no protocol attached */
 150
 151         if (hdlc->proto->open) {
 152                 int result = hdlc->proto->open(dev);
 153                 if (result)
 154                         return result;
 155         }
 156
 157         spin_lock_irq(&hdlc->state_lock);
 158
 159         if (hdlc->carrier) {
 160                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 161                 hdlc_proto_start(dev);
 162         } else
 163                 printk(KERN_INFO "%s: No carrier\n", dev->name);
 164
 165         hdlc->open = 1;
 166
 167         spin_unlock_irq(&hdlc->state_lock);
 168         return 0;
 169 }
 170
 171
 172
 173 /* Must be called by hardware driver when HDLC device is being closed */
 174 void hdlc_close(struct net_device *dev)
 175 {
 176         hdlc_device *hdlc = dev_to_hdlc(dev);
 177 #ifdef DEBUG_LINK
 178         printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
 179                hdlc->carrier, hdlc->open);
 180 #endif
 181
 182         spin_lock_irq(&hdlc->state_lock);
 183
 184         hdlc->open = 0;
 185         if (hdlc->carrier)
 186                 hdlc_proto_stop(dev);
 187
 188         spin_unlock_irq(&hdlc->state_lock);
 189
 190         if (hdlc->proto->close)
 191                 hdlc->proto->close(dev);
 192 }
 193
 194
 195
 196 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 197 {
 198         struct hdlc_proto *proto = first_proto;
 199         int result;
 200
 201         if (cmd != SIOCWANDEV)
 202                 return -EINVAL;
 203
 204         if (dev_to_hdlc(dev)->proto) {
 205                 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
 206                 if (result != -EINVAL)
 207                         return result;
 208         }
 209
 210         /* Not handled by currently attached protocol (if any) */
 211
 212         while (proto) {
 213                 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
 214                         return result;
 215                 proto = proto->next;
 216         }
 217         return -EINVAL;
 218 }
 219
 220 static const struct header_ops hdlc_null_ops;
 221
 222 static void hdlc_setup_dev(struct net_device *dev)
 223 {
 224         /* Re-init all variables changed by HDLC protocol drivers,
 225          * including ether_setup() called from hdlc_raw_eth.c.
 226          */
 227         dev->flags               = IFF_POINTOPOINT | IFF_NOARP;
 228         dev->priv_flags          = IFF_WAN_HDLC;
 229         dev->mtu                 = HDLC_MAX_MTU;
 230         dev->type                = ARPHRD_RAWHDLC;
 231         dev->hard_header_len     = 16;
 232         dev->addr_len            = 0;
 233         dev->header_ops          = &hdlc_null_ops;
 234
 235         dev->change_mtu          = hdlc_change_mtu;
 236 }
 237
 238 static void hdlc_setup(struct net_device *dev)
 239 {
 240         hdlc_device *hdlc = dev_to_hdlc(dev);
 241
 242         hdlc_setup_dev(dev);
 243         hdlc->carrier = 1;
 244         hdlc->open = 0;
 245         spin_lock_init(&hdlc->state_lock);
 246 }
 247
 248 struct net_device *alloc_hdlcdev(void *priv)
 249 {
 250         struct net_device *dev;
 251         dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d", hdlc_setup);
 252         if (dev)
 253                 dev_to_hdlc(dev)->priv = priv;
 254         return dev;
 255 }
 256
 257 void unregister_hdlc_device(struct net_device *dev)
 258 {
 259         rtnl_lock();
 260         unregister_netdevice(dev);
 261         detach_hdlc_protocol(dev);
 262         rtnl_unlock();
 263 }
 264
 265
 266
 267 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 268                          size_t size)
 269 {
 270         detach_hdlc_protocol(dev);
 271
 272         if (!try_module_get(proto->module))
 273                 return -ENOSYS;
 274
 275         if (size)
 276                 if ((dev_to_hdlc(dev)->state = kmalloc(size,
 277                                                        GFP_KERNEL)) == NULL) {
 278                         printk(KERN_WARNING "Memory squeeze on"
 279                                " hdlc_proto_attach()\n");
 280                         module_put(proto->module);
 281                         return -ENOBUFS;
 282                 }
 283         dev_to_hdlc(dev)->proto = proto;
 284         return 0;
 285 }
 286
 287
 288 void detach_hdlc_protocol(struct net_device *dev)
 289 {
 290         hdlc_device *hdlc = dev_to_hdlc(dev);
 291
 292         if (hdlc->proto) {
 293                 if (hdlc->proto->detach)
 294                         hdlc->proto->detach(dev);
 295                 module_put(hdlc->proto->module);
 296                 hdlc->proto = NULL;
 297         }
 298         kfree(hdlc->state);
 299         hdlc->state = NULL;
 300         hdlc_setup_dev(dev);
 301 }
 302
 303
 304 void register_hdlc_protocol(struct hdlc_proto *proto)
 305 {
 306         rtnl_lock();
 307         proto->next = first_proto;
 308         first_proto = proto;
 309         rtnl_unlock();
 310 }
 311
 312
 313 void unregister_hdlc_protocol(struct hdlc_proto *proto)
 314 {
 315         struct hdlc_proto **p;
 316
 317         rtnl_lock();
 318         p = &first_proto;
 319         while (*p != proto) {
 320                 BUG_ON(!*p);
 321                 p = &((*p)->next);
 322         }
 323         *p = proto->next;
 324         rtnl_unlock();
 325 }
 326
 327
 328
 329 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 330 MODULE_DESCRIPTION("HDLC support module");
 331 MODULE_LICENSE("GPL v2");
 332
 333 EXPORT_SYMBOL(hdlc_open);
 334 EXPORT_SYMBOL(hdlc_close);
 335 EXPORT_SYMBOL(hdlc_ioctl);
 336 EXPORT_SYMBOL(alloc_hdlcdev);
 337 EXPORT_SYMBOL(unregister_hdlc_device);
 338 EXPORT_SYMBOL(register_hdlc_protocol);
 339 EXPORT_SYMBOL(unregister_hdlc_protocol);
 340 EXPORT_SYMBOL(attach_hdlc_protocol);
 341 EXPORT_SYMBOL(detach_hdlc_protocol);
 342
 343 static struct packet_type hdlc_packet_type = {
 344         .type = __constant_htons(ETH_P_HDLC),
 345         .func = hdlc_rcv,
 346 };
 347
 348
 349 static struct notifier_block hdlc_notifier = {
 350         .notifier_call = hdlc_device_event,
 351 };
 352
 353
 354 static int __init hdlc_module_init(void)
 355 {
 356         int result;
 357
 358         printk(KERN_INFO "%s\n", version);
 359         if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
 360                 return result;
 361         dev_add_pack(&hdlc_packet_type);
 362         return 0;
 363 }
 364
 365
 366
 367 static void __exit hdlc_module_exit(void)
 368 {
 369         dev_remove_pack(&hdlc_packet_type);
 370         unregister_netdevice_notifier(&hdlc_notifier);
 371 }
 372
 373
 374 module_init(hdlc_module_init);
 375 module_exit(hdlc_module_exit);