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->get_stats != hdlc_get_stats)
 113                 return NOTIFY_DONE; /* not an HDLC device */
 114
 115         if (event != NETDEV_CHANGE)
 116                 return NOTIFY_DONE; /* Only interrested in carrier changes */
 117
 118         on = netif_carrier_ok(dev);
 119
 120 #ifdef DEBUG_LINK
 121         printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
 122                dev->name, on);
 123 #endif
 124
 125         hdlc = dev_to_hdlc(dev);
 126         spin_lock_irqsave(&hdlc->state_lock, flags);
 127
 128         if (hdlc->carrier == on)
 129                 goto carrier_exit; /* no change in DCD line level */
 130
 131         hdlc->carrier = on;
 132
 133         if (!hdlc->open)
 134                 goto carrier_exit;
 135
 136         if (hdlc->carrier) {
 137                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 138                 hdlc_proto_start(dev);
 139         } else {
 140                 printk(KERN_INFO "%s: Carrier lost\n", dev->name);
 141                 hdlc_proto_stop(dev);
 142         }
 143
 144 carrier_exit:
 145         spin_unlock_irqrestore(&hdlc->state_lock, flags);
 146         return NOTIFY_DONE;
 147 }
 148
 149
 150
 151 /* Must be called by hardware driver when HDLC device is being opened */
 152 int hdlc_open(struct net_device *dev)
 153 {
 154         hdlc_device *hdlc = dev_to_hdlc(dev);
 155 #ifdef DEBUG_LINK
 156         printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name,
 157                hdlc->carrier, hdlc->open);
 158 #endif
 159
 160         if (hdlc->proto == NULL)
 161                 return -ENOSYS; /* no protocol attached */
 162
 163         if (hdlc->proto->open) {
 164                 int result = hdlc->proto->open(dev);
 165                 if (result)
 166                         return result;
 167         }
 168
 169         spin_lock_irq(&hdlc->state_lock);
 170
 171         if (hdlc->carrier) {
 172                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 173                 hdlc_proto_start(dev);
 174         } else
 175                 printk(KERN_INFO "%s: No carrier\n", dev->name);
 176
 177         hdlc->open = 1;
 178
 179         spin_unlock_irq(&hdlc->state_lock);
 180         return 0;
 181 }
 182
 183
 184
 185 /* Must be called by hardware driver when HDLC device is being closed */
 186 void hdlc_close(struct net_device *dev)
 187 {
 188         hdlc_device *hdlc = dev_to_hdlc(dev);
 189 #ifdef DEBUG_LINK
 190         printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name,
 191                hdlc->carrier, hdlc->open);
 192 #endif
 193
 194         spin_lock_irq(&hdlc->state_lock);
 195
 196         hdlc->open = 0;
 197         if (hdlc->carrier)
 198                 hdlc_proto_stop(dev);
 199
 200         spin_unlock_irq(&hdlc->state_lock);
 201
 202         if (hdlc->proto->close)
 203                 hdlc->proto->close(dev);
 204 }
 205
 206
 207
 208 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 209 {
 210         struct hdlc_proto *proto = first_proto;
 211         int result;
 212
 213         if (cmd != SIOCWANDEV)
 214                 return -EINVAL;
 215
 216         if (dev_to_hdlc(dev)->proto) {
 217                 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr);
 218                 if (result != -EINVAL)
 219                         return result;
 220         }
 221
 222         /* Not handled by currently attached protocol (if any) */
 223
 224         while (proto) {
 225                 if ((result = proto->ioctl(dev, ifr)) != -EINVAL)
 226                         return result;
 227                 proto = proto->next;
 228         }
 229         return -EINVAL;
 230 }
 231
 232 static void hdlc_setup_dev(struct net_device *dev)
 233 {
 234         /* Re-init all variables changed by HDLC protocol drivers,
 235          * including ether_setup() called from hdlc_raw_eth.c.
 236          */
 237         dev->get_stats           = hdlc_get_stats;
 238         dev->flags               = IFF_POINTOPOINT | IFF_NOARP;
 239         dev->mtu                 = HDLC_MAX_MTU;
 240         dev->type                = ARPHRD_RAWHDLC;
 241         dev->hard_header_len     = 16;
 242         dev->addr_len            = 0;
 243         dev->hard_header         = NULL;
 244         dev->rebuild_header      = NULL;
 245         dev->set_mac_address     = NULL;
 246         dev->hard_header_cache   = NULL;
 247         dev->header_cache_update = NULL;
 248         dev->change_mtu          = hdlc_change_mtu;
 249         dev->hard_header_parse   = NULL;
 250 }
 251
 252 static void hdlc_setup(struct net_device *dev)
 253 {
 254         hdlc_device *hdlc = dev_to_hdlc(dev);
 255
 256         hdlc_setup_dev(dev);
 257         hdlc->carrier = 1;
 258         hdlc->open = 0;
 259         spin_lock_init(&hdlc->state_lock);
 260 }
 261
 262 struct net_device *alloc_hdlcdev(void *priv)
 263 {
 264         struct net_device *dev;
 265         dev = alloc_netdev(sizeof(struct hdlc_device_desc) +
 266                            sizeof(hdlc_device), "hdlc%d", hdlc_setup);
 267         if (dev)
 268                 dev_to_hdlc(dev)->priv = priv;
 269         return dev;
 270 }
 271
 272 void unregister_hdlc_device(struct net_device *dev)
 273 {
 274         rtnl_lock();
 275         unregister_netdevice(dev);
 276         detach_hdlc_protocol(dev);
 277         rtnl_unlock();
 278 }
 279
 280
 281
 282 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto,
 283                          int (*rx)(struct sk_buff *skb), size_t size)
 284 {
 285         detach_hdlc_protocol(dev);
 286
 287         if (!try_module_get(proto->module))
 288                 return -ENOSYS;
 289
 290         if (size)
 291                 if ((dev_to_hdlc(dev)->state = kmalloc(size,
 292                                                        GFP_KERNEL)) == NULL) {
 293                         printk(KERN_WARNING "Memory squeeze on"
 294                                " hdlc_proto_attach()\n");
 295                         module_put(proto->module);
 296                         return -ENOBUFS;
 297                 }
 298         dev_to_hdlc(dev)->proto = proto;
 299         dev_to_desc(dev)->netif_rx = rx;
 300         return 0;
 301 }
 302
 303
 304 void detach_hdlc_protocol(struct net_device *dev)
 305 {
 306         hdlc_device *hdlc = dev_to_hdlc(dev);
 307
 308         if (hdlc->proto) {
 309                 if (hdlc->proto->detach)
 310                         hdlc->proto->detach(dev);
 311                 module_put(hdlc->proto->module);
 312                 hdlc->proto = NULL;
 313         }
 314         kfree(hdlc->state);
 315         hdlc->state = NULL;
 316         hdlc_setup_dev(dev);
 317 }
 318
 319
 320 void register_hdlc_protocol(struct hdlc_proto *proto)
 321 {
 322         proto->next = first_proto;
 323         first_proto = proto;
 324 }
 325
 326
 327 void unregister_hdlc_protocol(struct hdlc_proto *proto)
 328 {
 329         struct hdlc_proto **p = &first_proto;
 330         while (*p) {
 331                 if (*p == proto) {
 332                         *p = proto->next;
 333                         return;
 334                 }
 335                 p = &((*p)->next);
 336         }
 337 }
 338
 339
 340
 341 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 342 MODULE_DESCRIPTION("HDLC support module");
 343 MODULE_LICENSE("GPL v2");
 344
 345 EXPORT_SYMBOL(hdlc_open);
 346 EXPORT_SYMBOL(hdlc_close);
 347 EXPORT_SYMBOL(hdlc_ioctl);
 348 EXPORT_SYMBOL(alloc_hdlcdev);
 349 EXPORT_SYMBOL(unregister_hdlc_device);
 350 EXPORT_SYMBOL(register_hdlc_protocol);
 351 EXPORT_SYMBOL(unregister_hdlc_protocol);
 352 EXPORT_SYMBOL(attach_hdlc_protocol);
 353 EXPORT_SYMBOL(detach_hdlc_protocol);
 354
 355 static struct packet_type hdlc_packet_type = {
 356         .type = __constant_htons(ETH_P_HDLC),
 357         .func = hdlc_rcv,
 358 };
 359
 360
 361 static struct notifier_block hdlc_notifier = {
 362         .notifier_call = hdlc_device_event,
 363 };
 364
 365
 366 static int __init hdlc_module_init(void)
 367 {
 368         int result;
 369
 370         printk(KERN_INFO "%s\n", version);
 371         if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
 372                 return result;
 373         dev_add_pack(&hdlc_packet_type);
 374         return 0;
 375 }
 376
 377
 378
 379 static void __exit hdlc_module_exit(void)
 380 {
 381         dev_remove_pack(&hdlc_packet_type);
 382         unregister_netdevice_notifier(&hdlc_notifier);
 383 }
 384
 385
 386 module_init(hdlc_module_init);
 387 module_exit(hdlc_module_exit);