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 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 (!net_eq(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 netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev) 70 { 71 hdlc_device *hdlc = dev_to_hdlc(dev); 72 73 if (hdlc->proto->xmit) 74 return hdlc->proto->xmit(skb, dev); 75 76 return hdlc->xmit(skb, dev); /* call hardware driver directly */ 77 } 78 79 static inline void hdlc_proto_start(struct net_device *dev) 80 { 81 hdlc_device *hdlc = dev_to_hdlc(dev); 82 if (hdlc->proto->start) 83 hdlc->proto->start(dev); 84 } 85 86 87 88 static inline void hdlc_proto_stop(struct net_device *dev) 89 { 90 hdlc_device *hdlc = dev_to_hdlc(dev); 91 if (hdlc->proto->stop) 92 hdlc->proto->stop(dev); 93 } 94 95 96 97 static int hdlc_device_event(struct notifier_block *this, unsigned long event, 98 void *ptr) 99 { 100 struct net_device *dev = ptr; 101 hdlc_device *hdlc; 102 unsigned long flags; 103 int on; 104 105 if (!net_eq(dev_net(dev), &init_net)) 106 return NOTIFY_DONE; 107 108 if (!(dev->priv_flags & IFF_WAN_HDLC)) 109 return NOTIFY_DONE; /* not an HDLC device */ 110 111 if (event != NETDEV_CHANGE) 112 return NOTIFY_DONE; /* Only interrested in carrier changes */ 113 114 on = netif_carrier_ok(dev); 115 116 #ifdef DEBUG_LINK 117 printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n", 118 dev->name, on); 119 #endif 120 121 hdlc = dev_to_hdlc(dev); 122 spin_lock_irqsave(&hdlc->state_lock, flags); 123 124 if (hdlc->carrier == on) 125 goto carrier_exit; /* no change in DCD line level */ 126 127 hdlc->carrier = on; 128 129 if (!hdlc->open) 130 goto carrier_exit; 131 132 if (hdlc->carrier) { 133 printk(KERN_INFO "%s: Carrier detected\n", dev->name); 134 hdlc_proto_start(dev); 135 } else { 136 printk(KERN_INFO "%s: Carrier lost\n", dev->name); 137 hdlc_proto_stop(dev); 138 } 139 140 carrier_exit: 141 spin_unlock_irqrestore(&hdlc->state_lock, flags); 142 return NOTIFY_DONE; 143 } 144 145 146 147 /* Must be called by hardware driver when HDLC device is being opened */ 148 int hdlc_open(struct net_device *dev) 149 { 150 hdlc_device *hdlc = dev_to_hdlc(dev); 151 #ifdef DEBUG_LINK 152 printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name, 153 hdlc->carrier, hdlc->open); 154 #endif 155 156 if (hdlc->proto == NULL) 157 return -ENOSYS; /* no protocol attached */ 158 159 if (hdlc->proto->open) { 160 int result = hdlc->proto->open(dev); 161 if (result) 162 return result; 163 } 164 165 spin_lock_irq(&hdlc->state_lock); 166 167 if (hdlc->carrier) { 168 printk(KERN_INFO "%s: Carrier detected\n", dev->name); 169 hdlc_proto_start(dev); 170 } else 171 printk(KERN_INFO "%s: No carrier\n", dev->name); 172 173 hdlc->open = 1; 174 175 spin_unlock_irq(&hdlc->state_lock); 176 return 0; 177 } 178 179 180 181 /* Must be called by hardware driver when HDLC device is being closed */ 182 void hdlc_close(struct net_device *dev) 183 { 184 hdlc_device *hdlc = dev_to_hdlc(dev); 185 #ifdef DEBUG_LINK 186 printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name, 187 hdlc->carrier, hdlc->open); 188 #endif 189 190 spin_lock_irq(&hdlc->state_lock); 191 192 hdlc->open = 0; 193 if (hdlc->carrier) 194 hdlc_proto_stop(dev); 195 196 spin_unlock_irq(&hdlc->state_lock); 197 198 if (hdlc->proto->close) 199 hdlc->proto->close(dev); 200 } 201 202 203 204 int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 205 { 206 struct hdlc_proto *proto = first_proto; 207 int result; 208 209 if (cmd != SIOCWANDEV) 210 return -EINVAL; 211 212 if (dev_to_hdlc(dev)->proto) { 213 result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr); 214 if (result != -EINVAL) 215 return result; 216 } 217 218 /* Not handled by currently attached protocol (if any) */ 219 220 while (proto) { 221 if ((result = proto->ioctl(dev, ifr)) != -EINVAL) 222 return result; 223 proto = proto->next; 224 } 225 return -EINVAL; 226 } 227 228 static const struct header_ops hdlc_null_ops; 229 230 static void hdlc_setup_dev(struct net_device *dev) 231 { 232 /* Re-init all variables changed by HDLC protocol drivers, 233 * including ether_setup() called from hdlc_raw_eth.c. 234 */ 235 dev->flags = IFF_POINTOPOINT | IFF_NOARP; 236 dev->priv_flags = IFF_WAN_HDLC; 237 dev->mtu = HDLC_MAX_MTU; 238 dev->type = ARPHRD_RAWHDLC; 239 dev->hard_header_len = 16; 240 dev->addr_len = 0; 241 dev->header_ops = &hdlc_null_ops; 242 } 243 244 static void hdlc_setup(struct net_device *dev) 245 { 246 hdlc_device *hdlc = dev_to_hdlc(dev); 247 248 hdlc_setup_dev(dev); 249 hdlc->carrier = 1; 250 hdlc->open = 0; 251 spin_lock_init(&hdlc->state_lock); 252 } 253 254 struct net_device *alloc_hdlcdev(void *priv) 255 { 256 struct net_device *dev; 257 dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d", hdlc_setup); 258 if (dev) 259 dev_to_hdlc(dev)->priv = priv; 260 return dev; 261 } 262 263 void unregister_hdlc_device(struct net_device *dev) 264 { 265 rtnl_lock(); 266 unregister_netdevice(dev); 267 detach_hdlc_protocol(dev); 268 rtnl_unlock(); 269 } 270 271 272 273 int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto, 274 size_t size) 275 { 276 detach_hdlc_protocol(dev); 277 278 if (!try_module_get(proto->module)) 279 return -ENOSYS; 280 281 if (size) 282 if ((dev_to_hdlc(dev)->state = kmalloc(size, 283 GFP_KERNEL)) == NULL) { 284 printk(KERN_WARNING "Memory squeeze on" 285 " hdlc_proto_attach()\n"); 286 module_put(proto->module); 287 return -ENOBUFS; 288 } 289 dev_to_hdlc(dev)->proto = proto; 290 return 0; 291 } 292 293 294 void detach_hdlc_protocol(struct net_device *dev) 295 { 296 hdlc_device *hdlc = dev_to_hdlc(dev); 297 298 if (hdlc->proto) { 299 if (hdlc->proto->detach) 300 hdlc->proto->detach(dev); 301 module_put(hdlc->proto->module); 302 hdlc->proto = NULL; 303 } 304 kfree(hdlc->state); 305 hdlc->state = NULL; 306 hdlc_setup_dev(dev); 307 } 308 309 310 void register_hdlc_protocol(struct hdlc_proto *proto) 311 { 312 rtnl_lock(); 313 proto->next = first_proto; 314 first_proto = proto; 315 rtnl_unlock(); 316 } 317 318 319 void unregister_hdlc_protocol(struct hdlc_proto *proto) 320 { 321 struct hdlc_proto **p; 322 323 rtnl_lock(); 324 p = &first_proto; 325 while (*p != proto) { 326 BUG_ON(!*p); 327 p = &((*p)->next); 328 } 329 *p = proto->next; 330 rtnl_unlock(); 331 } 332 333 334 335 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); 336 MODULE_DESCRIPTION("HDLC support module"); 337 MODULE_LICENSE("GPL v2"); 338 339 EXPORT_SYMBOL(hdlc_change_mtu); 340 EXPORT_SYMBOL(hdlc_start_xmit); 341 EXPORT_SYMBOL(hdlc_open); 342 EXPORT_SYMBOL(hdlc_close); 343 EXPORT_SYMBOL(hdlc_ioctl); 344 EXPORT_SYMBOL(alloc_hdlcdev); 345 EXPORT_SYMBOL(unregister_hdlc_device); 346 EXPORT_SYMBOL(register_hdlc_protocol); 347 EXPORT_SYMBOL(unregister_hdlc_protocol); 348 EXPORT_SYMBOL(attach_hdlc_protocol); 349 EXPORT_SYMBOL(detach_hdlc_protocol); 350 351 static struct packet_type hdlc_packet_type __read_mostly = { 352 .type = cpu_to_be16(ETH_P_HDLC), 353 .func = hdlc_rcv, 354 }; 355 356 357 static struct notifier_block hdlc_notifier = { 358 .notifier_call = hdlc_device_event, 359 }; 360 361 362 static int __init hdlc_module_init(void) 363 { 364 int result; 365 366 printk(KERN_INFO "%s\n", version); 367 if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0) 368 return result; 369 dev_add_pack(&hdlc_packet_type); 370 return 0; 371 } 372 373 374 375 static void __exit hdlc_module_exit(void) 376 { 377 dev_remove_pack(&hdlc_packet_type); 378 unregister_netdevice_notifier(&hdlc_notifier); 379 } 380 381 382 module_init(hdlc_module_init); 383 module_exit(hdlc_module_exit); 384