| 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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 26 | |
| 27 | #include <linux/errno.h> |
| 28 | #include <linux/hdlc.h> |
| 29 | #include <linux/if_arp.h> |
| 30 | #include <linux/inetdevice.h> |
| 31 | #include <linux/init.h> |
| 32 | #include <linux/kernel.h> |
| 33 | #include <linux/module.h> |
| 34 | #include <linux/notifier.h> |
| 35 | #include <linux/pkt_sched.h> |
| 36 | #include <linux/poll.h> |
| 37 | #include <linux/rtnetlink.h> |
| 38 | #include <linux/skbuff.h> |
| 39 | #include <linux/slab.h> |
| 40 | #include <net/net_namespace.h> |
| 41 | |
| 42 | |
| 43 | static const char* version = "HDLC support module revision 1.22"; |
| 44 | |
| 45 | #undef DEBUG_LINK |
| 46 | |
| 47 | static struct hdlc_proto *first_proto; |
| 48 | |
| 49 | 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 | static int hdlc_rcv(struct sk_buff *skb, struct net_device *dev, |
| 58 | struct packet_type *p, struct net_device *orig_dev) |
| 59 | { |
| 60 | struct hdlc_device *hdlc = dev_to_hdlc(dev); |
| 61 | |
| 62 | if (!net_eq(dev_net(dev), &init_net)) { |
| 63 | kfree_skb(skb); |
| 64 | return 0; |
| 65 | } |
| 66 | |
| 67 | BUG_ON(!hdlc->proto->netif_rx); |
| 68 | return hdlc->proto->netif_rx(skb); |
| 69 | } |
| 70 | |
| 71 | netdev_tx_t hdlc_start_xmit(struct sk_buff *skb, struct net_device *dev) |
| 72 | { |
| 73 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 74 | |
| 75 | if (hdlc->proto->xmit) |
| 76 | return hdlc->proto->xmit(skb, dev); |
| 77 | |
| 78 | return hdlc->xmit(skb, dev); /* call hardware driver directly */ |
| 79 | } |
| 80 | |
| 81 | static inline void hdlc_proto_start(struct net_device *dev) |
| 82 | { |
| 83 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 84 | if (hdlc->proto->start) |
| 85 | hdlc->proto->start(dev); |
| 86 | } |
| 87 | |
| 88 | |
| 89 | |
| 90 | static inline void hdlc_proto_stop(struct net_device *dev) |
| 91 | { |
| 92 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 93 | if (hdlc->proto->stop) |
| 94 | hdlc->proto->stop(dev); |
| 95 | } |
| 96 | |
| 97 | |
| 98 | |
| 99 | static int hdlc_device_event(struct notifier_block *this, unsigned long event, |
| 100 | void *ptr) |
| 101 | { |
| 102 | struct net_device *dev = netdev_notifier_info_to_dev(ptr); |
| 103 | hdlc_device *hdlc; |
| 104 | unsigned long flags; |
| 105 | int on; |
| 106 | |
| 107 | if (!net_eq(dev_net(dev), &init_net)) |
| 108 | return NOTIFY_DONE; |
| 109 | |
| 110 | if (!(dev->priv_flags & IFF_WAN_HDLC)) |
| 111 | return NOTIFY_DONE; /* not an HDLC device */ |
| 112 | |
| 113 | if (event != NETDEV_CHANGE) |
| 114 | return NOTIFY_DONE; /* Only interested in carrier changes */ |
| 115 | |
| 116 | on = netif_carrier_ok(dev); |
| 117 | |
| 118 | #ifdef DEBUG_LINK |
| 119 | printk(KERN_DEBUG "%s: hdlc_device_event NETDEV_CHANGE, carrier %i\n", |
| 120 | dev->name, on); |
| 121 | #endif |
| 122 | |
| 123 | hdlc = dev_to_hdlc(dev); |
| 124 | spin_lock_irqsave(&hdlc->state_lock, flags); |
| 125 | |
| 126 | if (hdlc->carrier == on) |
| 127 | goto carrier_exit; /* no change in DCD line level */ |
| 128 | |
| 129 | hdlc->carrier = on; |
| 130 | |
| 131 | if (!hdlc->open) |
| 132 | goto carrier_exit; |
| 133 | |
| 134 | if (hdlc->carrier) { |
| 135 | netdev_info(dev, "Carrier detected\n"); |
| 136 | hdlc_proto_start(dev); |
| 137 | } else { |
| 138 | netdev_info(dev, "Carrier lost\n"); |
| 139 | hdlc_proto_stop(dev); |
| 140 | } |
| 141 | |
| 142 | carrier_exit: |
| 143 | spin_unlock_irqrestore(&hdlc->state_lock, flags); |
| 144 | return NOTIFY_DONE; |
| 145 | } |
| 146 | |
| 147 | |
| 148 | |
| 149 | /* Must be called by hardware driver when HDLC device is being opened */ |
| 150 | int hdlc_open(struct net_device *dev) |
| 151 | { |
| 152 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 153 | #ifdef DEBUG_LINK |
| 154 | printk(KERN_DEBUG "%s: hdlc_open() carrier %i open %i\n", dev->name, |
| 155 | hdlc->carrier, hdlc->open); |
| 156 | #endif |
| 157 | |
| 158 | if (hdlc->proto == NULL) |
| 159 | return -ENOSYS; /* no protocol attached */ |
| 160 | |
| 161 | if (hdlc->proto->open) { |
| 162 | int result = hdlc->proto->open(dev); |
| 163 | if (result) |
| 164 | return result; |
| 165 | } |
| 166 | |
| 167 | spin_lock_irq(&hdlc->state_lock); |
| 168 | |
| 169 | if (hdlc->carrier) { |
| 170 | netdev_info(dev, "Carrier detected\n"); |
| 171 | hdlc_proto_start(dev); |
| 172 | } else |
| 173 | netdev_info(dev, "No carrier\n"); |
| 174 | |
| 175 | hdlc->open = 1; |
| 176 | |
| 177 | spin_unlock_irq(&hdlc->state_lock); |
| 178 | return 0; |
| 179 | } |
| 180 | |
| 181 | |
| 182 | |
| 183 | /* Must be called by hardware driver when HDLC device is being closed */ |
| 184 | void hdlc_close(struct net_device *dev) |
| 185 | { |
| 186 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 187 | #ifdef DEBUG_LINK |
| 188 | printk(KERN_DEBUG "%s: hdlc_close() carrier %i open %i\n", dev->name, |
| 189 | hdlc->carrier, hdlc->open); |
| 190 | #endif |
| 191 | |
| 192 | spin_lock_irq(&hdlc->state_lock); |
| 193 | |
| 194 | hdlc->open = 0; |
| 195 | if (hdlc->carrier) |
| 196 | hdlc_proto_stop(dev); |
| 197 | |
| 198 | spin_unlock_irq(&hdlc->state_lock); |
| 199 | |
| 200 | if (hdlc->proto->close) |
| 201 | hdlc->proto->close(dev); |
| 202 | } |
| 203 | |
| 204 | |
| 205 | |
| 206 | int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) |
| 207 | { |
| 208 | struct hdlc_proto *proto = first_proto; |
| 209 | int result; |
| 210 | |
| 211 | if (cmd != SIOCWANDEV) |
| 212 | return -EINVAL; |
| 213 | |
| 214 | if (dev_to_hdlc(dev)->proto) { |
| 215 | result = dev_to_hdlc(dev)->proto->ioctl(dev, ifr); |
| 216 | if (result != -EINVAL) |
| 217 | return result; |
| 218 | } |
| 219 | |
| 220 | /* Not handled by currently attached protocol (if any) */ |
| 221 | |
| 222 | while (proto) { |
| 223 | if ((result = proto->ioctl(dev, ifr)) != -EINVAL) |
| 224 | return result; |
| 225 | proto = proto->next; |
| 226 | } |
| 227 | return -EINVAL; |
| 228 | } |
| 229 | |
| 230 | static const struct header_ops hdlc_null_ops; |
| 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->flags = IFF_POINTOPOINT | IFF_NOARP; |
| 238 | dev->priv_flags = IFF_WAN_HDLC; |
| 239 | dev->mtu = HDLC_MAX_MTU; |
| 240 | dev->type = ARPHRD_RAWHDLC; |
| 241 | dev->hard_header_len = 16; |
| 242 | dev->addr_len = 0; |
| 243 | dev->header_ops = &hdlc_null_ops; |
| 244 | } |
| 245 | |
| 246 | static void hdlc_setup(struct net_device *dev) |
| 247 | { |
| 248 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 249 | |
| 250 | hdlc_setup_dev(dev); |
| 251 | hdlc->carrier = 1; |
| 252 | hdlc->open = 0; |
| 253 | spin_lock_init(&hdlc->state_lock); |
| 254 | } |
| 255 | |
| 256 | struct net_device *alloc_hdlcdev(void *priv) |
| 257 | { |
| 258 | struct net_device *dev; |
| 259 | dev = alloc_netdev(sizeof(struct hdlc_device), "hdlc%d", |
| 260 | NET_NAME_UNKNOWN, hdlc_setup); |
| 261 | if (dev) |
| 262 | dev_to_hdlc(dev)->priv = priv; |
| 263 | return dev; |
| 264 | } |
| 265 | |
| 266 | void unregister_hdlc_device(struct net_device *dev) |
| 267 | { |
| 268 | rtnl_lock(); |
| 269 | detach_hdlc_protocol(dev); |
| 270 | unregister_netdevice(dev); |
| 271 | rtnl_unlock(); |
| 272 | } |
| 273 | |
| 274 | |
| 275 | |
| 276 | int attach_hdlc_protocol(struct net_device *dev, struct hdlc_proto *proto, |
| 277 | size_t size) |
| 278 | { |
| 279 | int err; |
| 280 | |
| 281 | err = detach_hdlc_protocol(dev); |
| 282 | if (err) |
| 283 | return err; |
| 284 | |
| 285 | if (!try_module_get(proto->module)) |
| 286 | return -ENOSYS; |
| 287 | |
| 288 | if (size) { |
| 289 | dev_to_hdlc(dev)->state = kmalloc(size, GFP_KERNEL); |
| 290 | if (dev_to_hdlc(dev)->state == NULL) { |
| 291 | module_put(proto->module); |
| 292 | return -ENOBUFS; |
| 293 | } |
| 294 | } |
| 295 | dev_to_hdlc(dev)->proto = proto; |
| 296 | |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | |
| 301 | int detach_hdlc_protocol(struct net_device *dev) |
| 302 | { |
| 303 | hdlc_device *hdlc = dev_to_hdlc(dev); |
| 304 | int err; |
| 305 | |
| 306 | if (hdlc->proto) { |
| 307 | err = call_netdevice_notifiers(NETDEV_PRE_TYPE_CHANGE, dev); |
| 308 | err = notifier_to_errno(err); |
| 309 | if (err) { |
| 310 | netdev_err(dev, "Refused to change device type\n"); |
| 311 | return err; |
| 312 | } |
| 313 | |
| 314 | if (hdlc->proto->detach) |
| 315 | hdlc->proto->detach(dev); |
| 316 | module_put(hdlc->proto->module); |
| 317 | hdlc->proto = NULL; |
| 318 | } |
| 319 | kfree(hdlc->state); |
| 320 | hdlc->state = NULL; |
| 321 | hdlc_setup_dev(dev); |
| 322 | |
| 323 | return 0; |
| 324 | } |
| 325 | |
| 326 | |
| 327 | void register_hdlc_protocol(struct hdlc_proto *proto) |
| 328 | { |
| 329 | rtnl_lock(); |
| 330 | proto->next = first_proto; |
| 331 | first_proto = proto; |
| 332 | rtnl_unlock(); |
| 333 | } |
| 334 | |
| 335 | |
| 336 | void unregister_hdlc_protocol(struct hdlc_proto *proto) |
| 337 | { |
| 338 | struct hdlc_proto **p; |
| 339 | |
| 340 | rtnl_lock(); |
| 341 | p = &first_proto; |
| 342 | while (*p != proto) { |
| 343 | BUG_ON(!*p); |
| 344 | p = &((*p)->next); |
| 345 | } |
| 346 | *p = proto->next; |
| 347 | rtnl_unlock(); |
| 348 | } |
| 349 | |
| 350 | |
| 351 | |
| 352 | MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); |
| 353 | MODULE_DESCRIPTION("HDLC support module"); |
| 354 | MODULE_LICENSE("GPL v2"); |
| 355 | |
| 356 | EXPORT_SYMBOL(hdlc_change_mtu); |
| 357 | EXPORT_SYMBOL(hdlc_start_xmit); |
| 358 | EXPORT_SYMBOL(hdlc_open); |
| 359 | EXPORT_SYMBOL(hdlc_close); |
| 360 | EXPORT_SYMBOL(hdlc_ioctl); |
| 361 | EXPORT_SYMBOL(alloc_hdlcdev); |
| 362 | EXPORT_SYMBOL(unregister_hdlc_device); |
| 363 | EXPORT_SYMBOL(register_hdlc_protocol); |
| 364 | EXPORT_SYMBOL(unregister_hdlc_protocol); |
| 365 | EXPORT_SYMBOL(attach_hdlc_protocol); |
| 366 | EXPORT_SYMBOL(detach_hdlc_protocol); |
| 367 | |
| 368 | static struct packet_type hdlc_packet_type __read_mostly = { |
| 369 | .type = cpu_to_be16(ETH_P_HDLC), |
| 370 | .func = hdlc_rcv, |
| 371 | }; |
| 372 | |
| 373 | |
| 374 | static struct notifier_block hdlc_notifier = { |
| 375 | .notifier_call = hdlc_device_event, |
| 376 | }; |
| 377 | |
| 378 | |
| 379 | static int __init hdlc_module_init(void) |
| 380 | { |
| 381 | int result; |
| 382 | |
| 383 | pr_info("%s\n", version); |
| 384 | if ((result = register_netdevice_notifier(&hdlc_notifier)) != 0) |
| 385 | return result; |
| 386 | dev_add_pack(&hdlc_packet_type); |
| 387 | return 0; |
| 388 | } |
| 389 | |
| 390 | |
| 391 | |
| 392 | static void __exit hdlc_module_exit(void) |
| 393 | { |
| 394 | dev_remove_pack(&hdlc_packet_type); |
| 395 | unregister_netdevice_notifier(&hdlc_notifier); |
| 396 | } |
| 397 | |
| 398 | |
| 399 | module_init(hdlc_module_init); |
| 400 | module_exit(hdlc_module_exit); |