drivers/net/wan/hdlc.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  *
   4  * Copyright (C) 1999 - 2006 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/module.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28 #include <linux/poll.h>
  29 #include <linux/errno.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/init.h>
  32 #include <linux/skbuff.h>
  33 #include <linux/pkt_sched.h>
  34 #include <linux/inetdevice.h>
  35 #include <linux/lapb.h>
  36 #include <linux/rtnetlink.h>
  37 #include <linux/notifier.h>
  38 #include <linux/hdlc.h>
  39 #include <net/net_namespace.h>
  40
  41
  42 static const char* version = "HDLC support module revision 1.21";
  43
  44 #undef DEBUG_LINK
  45
  46 static struct hdlc_proto *first_proto = NULL;
  47
  48
  49 static int hdlc_change_mtu(struct net_device *dev, int new_mtu)
  50 {
  51         if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
  52                 return -EINVAL;
  53         dev->mtu = new_mtu;
  54         return 0;
  55 }
  56
  57
  58
  59 static struct net_device_stats *hdlc_get_stats(struct net_device *dev)
  60 {
  61         return hdlc_stats(dev);
  62 }
  63
  64
  65
  66 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
  67                     struct packet_type *p, struct net_device *orig_dev)
  68 {
  69         struct hdlc_device_desc *desc = dev_to_desc(dev);
  70
  71         if (dev->nd_net != &init_net) {
  72                 kfree_skb(skb);
  73                 return 0;
  74         }
  75
  76         if (desc->netif_rx)
  77                 return desc->netif_rx(skb);
  78
  79         desc->stats.rx_dropped++; /* Shouldn't happen */
  80         dev_kfree_skb(skb);
  81         return NET_RX_DROP;
  82 }
  83
  84
  85
  86 static inline void hdlc_proto_start(struct net_device *dev)
  87 {
  88         hdlc_device *hdlc = dev_to_hdlc(dev);
  89         if (hdlc->proto->start)
  90                 return hdlc->proto->start(dev);
  91 }
  92
  93
  94
  95 static inline void hdlc_proto_stop(struct net_device *dev)
  96 {
  97         hdlc_device *hdlc = dev_to_hdlc(dev);
  98         if (hdlc->proto->stop)
  99                 return hdlc->proto->stop(dev);
 100 }
 101
 102
 103
 104 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
 105                              void *ptr)
 106 {
 107         struct net_device *dev = ptr;
 108         hdlc_device *hdlc;
 109         unsigned long flags;
 110         int on;
 111
 112         if (dev->nd_net != &init_net)
 113                 return NOTIFY_DONE;
 114
 115         if (dev->get_stats != hdlc_get_stats)
 116                 return NOTIFY_DONE; /* not an HDLC device */
 117
 118         if (event != NETDEV_CHANGE)
 119                 return NOTIFY_DONE; /* Only interrested in carrier changes */
 120
 121         on = netif_carrier_ok(dev);
 122
 123 #ifdef DEBUG_LINK
 124         printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
 125                dev->name, on);
 126 #endif
 127
 128         hdlc = dev_to_hdlc(dev);
 129         spin_lock_irqsave(&hdlc->state_lock, flags);
 130
 131         if (hdlc->carrier == on)
 132                 goto carrier_exit; /* no change in DCD line level */
 133
 134         hdlc->carrier = on;
 135
 136         if (!hdlc->open)
 137                 goto carrier_exit;
 138
 139         if (hdlc->carrier) {
 140                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 141                 hdlc_proto_start(dev);
 142         } else {
 143                 printk(KERN_INFO "%s: Carrier lost\n", dev->name);
 144                 hdlc_proto_stop(dev);
 145         }
 146
 147 carrier_exit:
 148         spin_unlock_irqrestore(&hdlc->state_lock, flags);
 149         return NOTIFY_DONE;
 150 }
 151
 152
 153
 154 /* Must be called by hardware driver when HDLC device is being opened */
 155 int hdlc_open(struct net_device *dev)
 156 {
 157         hdlc_device *hdlc = dev_to_hdlc(dev);
 158 #ifdef DEBUG_LINK
 159         printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
 160                hdlc->carrier, hdlc->open);
 161 #endif
 162
 163         if (hdlc->proto == NULL)
 164                 return -ENOSYS; /* no protocol attached */
 165
 166         if (hdlc->proto->open) {
 167                 int result = hdlc->proto->open(dev);
 168                 if (result)
 169                         return result;
 170         }
 171
 172         spin_lock_irq(&hdlc->state_lock);
 173
 174         if (hdlc->carrier) {
 175                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 176                 hdlc_proto_start(dev);
 177         } else
 178                 printk(KERN_INFO "%s: No carrier\n", dev->name);
 179
 180         hdlc->open = 1;
 181
 182         spin_unlock_irq(&hdlc->state_lock);
 183         return 0;
 184 }
 185
 186
 187
 188 /* Must be called by hardware driver when HDLC device is being closed */
 189 void hdlc_close(struct net_device *dev)
 190 {
 191         hdlc_device *hdlc = dev_to_hdlc(dev);
 192 #ifdef DEBUG_LINK
 193         printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
 194                hdlc->carrier, hdlc->open);
 195 #endif
 196
 197         spin_lock_irq(&hdlc->state_lock);
 198
 199         hdlc->open = 0;
 200         if (hdlc->carrier)
 201                 hdlc_proto_stop(dev);
 202
 203         spin_unlock_irq(&hdlc->state_lock);
 204
 205         if (hdlc->proto->close)
 206                 hdlc->proto->close(dev);
 207 }
 208
 209
 210
 211 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 212 {
 213         struct hdlc_proto *proto = first_proto;
 214         int result;
 215
 216         if (cmd != SIOCWANDEV)
 217                 return -EINVAL;
 218
 219         if (dev_to_hdlc(dev)->proto) {
 220                 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
 221                 if (result != -EINVAL)
 222                         return result;
 223         }
 224
 225         /* Not handled by currently attached protocol (if any) */
 226
 227         while (proto) {
 228                 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
 229                         return result;
 230                 proto = proto->next;
 231         }
 232         return -EINVAL;
 233 }
 234
 235 static const struct header_ops hdlc_null_ops;
 236
 237 static void hdlc_setup_dev(struct net_device *dev)
 238 {
 239         /* Re-init all variables changed by HDLC protocol drivers,
 240          * including ether_setup() called from hdlc_raw_eth.c.
 241          */
 242         dev->get_stats           = hdlc_get_stats;
 243         dev->flags               = IFF_POINTOPOINT | IFF_NOARP;
 244         dev->mtu                 = HDLC_MAX_MTU;
 245         dev->type                = ARPHRD_RAWHDLC;
 246         dev->hard_header_len     = 16;
 247         dev->addr_len            = 0;
 248         dev->header_ops          = &hdlc_null_ops;
 249
 250         dev->change_mtu          = hdlc_change_mtu;
 251 }
 252
 253 static void hdlc_setup(struct net_device *dev)
 254 {
 255         hdlc_device *hdlc = dev_to_hdlc(dev);
 256
 257         hdlc_setup_dev(dev);
 258         hdlc->carrier = 1;
 259         hdlc->open = 0;
 260         spin_lock_init(&hdlc->state_lock);
 261 }
 262
 263 struct net_device *alloc_hdlcdev(void *priv)
 264 {
 265         struct net_device *dev;
 266         dev = alloc_netdev(sizeof(struct hdlc_device_desc) +
 267                            sizeof(hdlc_device), "hdlc%d", hdlc_setup);
 268         if (dev)
 269                 dev_to_hdlc(dev)->priv = priv;
 270         return dev;
 271 }
 272
 273 void unregister_hdlc_device(struct net_device *dev)
 274 {
 275         rtnl_lock();
 276         unregister_netdevice(dev);
 277         detach_hdlc_protocol(dev);
 278         rtnl_unlock();
 279 }
 280
 281
 282
 283 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 284                          int (*rx)(struct sk_buff *skb), size_t size)
 285 {
 286         detach_hdlc_protocol(dev);
 287
 288         if (!try_module_get(proto->module))
 289                 return -ENOSYS;
 290
 291         if (size)
 292                 if ((dev_to_hdlc(dev)->state = kmalloc(size,
 293                                                        GFP_KERNEL)) == NULL) {
 294                         printk(KERN_WARNING "Memory squeeze on"
 295                                " hdlc_proto_attach()\n");
 296                         module_put(proto->module);
 297                         return -ENOBUFS;
 298                 }
 299         dev_to_hdlc(dev)->proto = proto;
 300         dev_to_desc(dev)->netif_rx = rx;
 301         return 0;
 302 }
 303
 304
 305 void detach_hdlc_protocol(struct net_device *dev)
 306 {
 307         hdlc_device *hdlc = dev_to_hdlc(dev);
 308
 309         if (hdlc->proto) {
 310                 if (hdlc->proto->detach)
 311                         hdlc->proto->detach(dev);
 312                 module_put(hdlc->proto->module);
 313                 hdlc->proto = NULL;
 314         }
 315         kfree(hdlc->state);
 316         hdlc->state = NULL;
 317         hdlc_setup_dev(dev);
 318 }
 319
 320
 321 void register_hdlc_protocol(struct hdlc_proto *proto)
 322 {
 323         proto->next = first_proto;
 324         first_proto = proto;
 325 }
 326
 327
 328 void unregister_hdlc_protocol(struct hdlc_proto *proto)
 329 {
 330         struct hdlc_proto **p = &first_proto;
 331         while (*p) {
 332                 if (*p == proto) {
 333                         *p = proto->next;
 334                         return;
 335                 }
 336                 p = &((*p)->next);
 337         }
 338 }
 339
 340
 341
 342 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 343 MODULE_DESCRIPTION("HDLC support module");
 344 MODULE_LICENSE("GPL v2");
 345
 346 EXPORT_SYMBOL(hdlc_open);
 347 EXPORT_SYMBOL(hdlc_close);
 348 EXPORT_SYMBOL(hdlc_ioctl);
 349 EXPORT_SYMBOL(alloc_hdlcdev);
 350 EXPORT_SYMBOL(unregister_hdlc_device);
 351 EXPORT_SYMBOL(register_hdlc_protocol);
 352 EXPORT_SYMBOL(unregister_hdlc_protocol);
 353 EXPORT_SYMBOL(attach_hdlc_protocol);
 354 EXPORT_SYMBOL(detach_hdlc_protocol);
 355
 356 static struct packet_type hdlc_packet_type = {
 357         .type = __constant_htons(ETH_P_HDLC),
 358         .func = hdlc_rcv,
 359 };
 360
 361
 362 static struct notifier_block hdlc_notifier = {
 363         .notifier_call = hdlc_device_event,
 364 };
 365
 366
 367 static int __init hdlc_module_init(void)
 368 {
 369         int result;
 370
 371         printk(KERN_INFO "%s\n", version);
 372         if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
 373                 return result;
 374         dev_add_pack(&hdlc_packet_type);
 375         return 0;
 376 }
 377
 378
 379
 380 static void __exit hdlc_module_exit(void)
 381 {
 382         dev_remove_pack(&hdlc_packet_type);
 383         unregister_netdevice_notifier(&hdlc_notifier);
 384 }
 385
 386
 387 module_init(hdlc_module_init);
 388 module_exit(hdlc_module_exit);