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); 389