drivers/net/wan/hdlc_generic.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  *
   4  * Copyright (C) 1999 - 2005 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
  40
  41 static const char* version = "HDLC support module revision 1.19";
  42
  43 #undef DEBUG_LINK
  44
  45
  46 static int hdlc_change_mtu(struct net_device *dev, int new_mtu)
  47 {
  48         if ((new_mtu < 68) || (new_mtu > HDLC_MAX_MTU))
  49                 return -EINVAL;
  50         dev->mtu = new_mtu;
  51         return 0;
  52 }
  53
  54
  55
  56 static struct net_device_stats *hdlc_get_stats(struct net_device *dev)
  57 {
  58         return hdlc_stats(dev);
  59 }
  60
  61
  62
  63 static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev,
  64                     struct packet_type *p, struct net_device *orig_dev)
  65 {
  66         hdlc_device *hdlc = dev_to_hdlc(dev);
  67         if (hdlc->proto.netif_rx)
  68                 return hdlc->proto.netif_rx(skb);
  69
  70         hdlc->stats.rx_dropped++; /* Shouldn't happen */
  71         dev_kfree_skb(skb);
  72         return NET_RX_DROP;
  73 }
  74
  75
  76
  77 static inline void hdlc_proto_start(struct net_device *dev)
  78 {
  79         hdlc_device *hdlc = dev_to_hdlc(dev);
  80         if (hdlc->proto.start)
  81                 return hdlc->proto.start(dev);
  82 }
  83
  84
  85
  86 static inline void hdlc_proto_stop(struct net_device *dev)
  87 {
  88         hdlc_device *hdlc = dev_to_hdlc(dev);
  89         if (hdlc->proto.stop)
  90                 return hdlc->proto.stop(dev);
  91 }
  92
  93
  94
  95 static int hdlc_device_event(struct notifier_block *this, unsigned long event,
  96                              void *ptr)
  97 {
  98         struct net_device *dev = ptr;
  99         hdlc_device *hdlc;
 100         unsigned long flags;
 101         int on;
 102
 103         if (dev->get_stats != hdlc_get_stats)
 104                 return NOTIFY_DONE; /* not an HDLC device */
 105
 106         if (event != NETDEV_CHANGE)
 107                 return NOTIFY_DONE; /* Only interrested in carrier changes */
 108
 109         on = netif_carrier_ok(dev);
 110
 111 #ifdef DEBUG_LINK
 112         printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n",
 113                dev->name, on);
 114 #endif
 115
 116         hdlc = dev_to_hdlc(dev);
 117         spin_lock_irqsave(&hdlc->state_lock, flags);
 118
 119         if (hdlc->carrier == on)
 120                 goto carrier_exit; /* no change in DCD line level */
 121
 122         hdlc->carrier = on;
 123
 124         if (!hdlc->open)
 125                 goto carrier_exit;
 126
 127         if (hdlc->carrier) {
 128                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 129                 hdlc_proto_start(dev);
 130         } else {
 131                 printk(KERN_INFO "%s: Carrier lost\n", dev->name);
 132                 hdlc_proto_stop(dev);
 133         }
 134
 135 carrier_exit:
 136         spin_unlock_irqrestore(&hdlc->state_lock, flags);
 137         return NOTIFY_DONE;
 138 }
 139
 140
 141
 142 /* Must be called by hardware driver when HDLC device is being opened */
 143 int hdlc_open(struct net_device *dev)
 144 {
 145         hdlc_device *hdlc = dev_to_hdlc(dev);
 146 #ifdef DEBUG_LINK
 147         printk(KERN_DEBUG "hdlc_open() carrier %i open %i\n",
 148                hdlc->carrier, hdlc->open);
 149 #endif
 150
 151         if (hdlc->proto.id == -1)
 152                 return -ENOSYS; /* no protocol attached */
 153
 154         if (hdlc->proto.open) {
 155                 int result = hdlc->proto.open(dev);
 156                 if (result)
 157                         return result;
 158         }
 159
 160         spin_lock_irq(&hdlc->state_lock);
 161
 162         if (hdlc->carrier) {
 163                 printk(KERN_INFO "%s: Carrier detected\n", dev->name);
 164                 hdlc_proto_start(dev);
 165         } else
 166                 printk(KERN_INFO "%s: No carrier\n", dev->name);
 167
 168         hdlc->open = 1;
 169
 170         spin_unlock_irq(&hdlc->state_lock);
 171         return 0;
 172 }
 173
 174
 175
 176 /* Must be called by hardware driver when HDLC device is being closed */
 177 void hdlc_close(struct net_device *dev)
 178 {
 179         hdlc_device *hdlc = dev_to_hdlc(dev);
 180 #ifdef DEBUG_LINK
 181         printk(KERN_DEBUG "hdlc_close() carrier %i open %i\n",
 182                hdlc->carrier, hdlc->open);
 183 #endif
 184
 185         spin_lock_irq(&hdlc->state_lock);
 186
 187         hdlc->open = 0;
 188         if (hdlc->carrier)
 189                 hdlc_proto_stop(dev);
 190
 191         spin_unlock_irq(&hdlc->state_lock);
 192
 193         if (hdlc->proto.close)
 194                 hdlc->proto.close(dev);
 195 }
 196
 197
 198
 199 #ifndef CONFIG_HDLC_RAW
 200 #define hdlc_raw_ioctl(dev, ifr)        -ENOSYS
 201 #endif
 202
 203 #ifndef CONFIG_HDLC_RAW_ETH
 204 #define hdlc_raw_eth_ioctl(dev, ifr)    -ENOSYS
 205 #endif
 206
 207 #ifndef CONFIG_HDLC_PPP
 208 #define hdlc_ppp_ioctl(dev, ifr)        -ENOSYS
 209 #endif
 210
 211 #ifndef CONFIG_HDLC_CISCO
 212 #define hdlc_cisco_ioctl(dev, ifr)      -ENOSYS
 213 #endif
 214
 215 #ifndef CONFIG_HDLC_FR
 216 #define hdlc_fr_ioctl(dev, ifr)         -ENOSYS
 217 #endif
 218
 219 #ifndef CONFIG_HDLC_X25
 220 #define hdlc_x25_ioctl(dev, ifr)        -ENOSYS
 221 #endif
 222
 223
 224 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 225 {
 226         hdlc_device *hdlc = dev_to_hdlc(dev);
 227         unsigned int proto;
 228
 229         if (cmd != SIOCWANDEV)
 230                 return -EINVAL;
 231
 232         switch(ifr->ifr_settings.type) {
 233         case IF_PROTO_HDLC:
 234         case IF_PROTO_HDLC_ETH:
 235         case IF_PROTO_PPP:
 236         case IF_PROTO_CISCO:
 237         case IF_PROTO_FR:
 238         case IF_PROTO_X25:
 239                 proto = ifr->ifr_settings.type;
 240                 break;
 241
 242         default:
 243                 proto = hdlc->proto.id;
 244         }
 245
 246         switch(proto) {
 247         case IF_PROTO_HDLC:     return hdlc_raw_ioctl(dev, ifr);
 248         case IF_PROTO_HDLC_ETH: return hdlc_raw_eth_ioctl(dev, ifr);
 249         case IF_PROTO_PPP:      return hdlc_ppp_ioctl(dev, ifr);
 250         case IF_PROTO_CISCO:    return hdlc_cisco_ioctl(dev, ifr);
 251         case IF_PROTO_FR:       return hdlc_fr_ioctl(dev, ifr);
 252         case IF_PROTO_X25:      return hdlc_x25_ioctl(dev, ifr);
 253         default:                return -EINVAL;
 254         }
 255 }
 256
 257 void hdlc_setup(struct net_device *dev)
 258 {
 259         hdlc_device *hdlc = dev_to_hdlc(dev);
 260
 261         dev->get_stats = hdlc_get_stats;
 262         dev->change_mtu = hdlc_change_mtu;
 263         dev->mtu = HDLC_MAX_MTU;
 264
 265         dev->type = ARPHRD_RAWHDLC;
 266         dev->hard_header_len = 16;
 267
 268         dev->flags = IFF_POINTOPOINT | IFF_NOARP;
 269
 270         hdlc->proto.id = -1;
 271         hdlc->proto.detach = NULL;
 272         hdlc->carrier = 1;
 273         hdlc->open = 0;
 274         spin_lock_init(&hdlc->state_lock);
 275 }
 276
 277 struct net_device *alloc_hdlcdev(void *priv)
 278 {
 279         struct net_device *dev;
 280         dev = alloc_netdev(sizeof(hdlc_device), "hdlc%d", hdlc_setup);
 281         if (dev)
 282                 dev_to_hdlc(dev)->priv = priv;
 283         return dev;
 284 }
 285
 286 void unregister_hdlc_device(struct net_device *dev)
 287 {
 288         rtnl_lock();
 289         hdlc_proto_detach(dev_to_hdlc(dev));
 290         unregister_netdevice(dev);
 291         rtnl_unlock();
 292 }
 293
 294
 295
 296 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 297 MODULE_DESCRIPTION("HDLC support module");
 298 MODULE_LICENSE("GPL v2");
 299
 300 EXPORT_SYMBOL(hdlc_open);
 301 EXPORT_SYMBOL(hdlc_close);
 302 EXPORT_SYMBOL(hdlc_ioctl);
 303 EXPORT_SYMBOL(hdlc_setup);
 304 EXPORT_SYMBOL(alloc_hdlcdev);
 305 EXPORT_SYMBOL(unregister_hdlc_device);
 306
 307 static struct packet_type hdlc_packet_type = {
 308         .type = __constant_htons(ETH_P_HDLC),
 309         .func = hdlc_rcv,
 310 };
 311
 312
 313 static struct notifier_block hdlc_notifier = {
 314         .notifier_call = hdlc_device_event,
 315 };
 316
 317
 318 static int __init hdlc_module_init(void)
 319 {
 320         int result;
 321
 322         printk(KERN_INFO "%s\n", version);
 323         if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0)
 324                 return result;
 325         dev_add_pack(&hdlc_packet_type);
 326         return 0;
 327 }
 328
 329
 330
 331 static void __exit hdlc_module_exit(void)
 332 {
 333         dev_remove_pack(&hdlc_packet_type);
 334         unregister_netdevice_notifier(&hdlc_notifier);
 335 }
 336
 337
 338 module_init(hdlc_module_init);
 339 module_exit(hdlc_module_exit);