drivers/net/wan/hdlc_cisco.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  * Cisco HDLC support
   4  *
   5  * Copyright (C) 2000 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of version 2 of the GNU General Public License
   9  * as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/hdlc.h>
  14 #include <linux/if_arp.h>
  15 #include <linux/inetdevice.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/pkt_sched.h>
  20 #include <linux/poll.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/skbuff.h>
  23
  24 #undef DEBUG_HARD_HEADER
  25
  26 #define CISCO_MULTICAST         0x8F    /* Cisco multicast address */
  27 #define CISCO_UNICAST           0x0F    /* Cisco unicast address */
  28 #define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
  29 #define CISCO_SYS_INFO          0x2000  /* Cisco interface/system info */
  30 #define CISCO_ADDR_REQ          0       /* Cisco address request */
  31 #define CISCO_ADDR_REPLY        1       /* Cisco address reply */
  32 #define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */
  33
  34
  35 struct hdlc_header {
  36         u8 address;
  37         u8 control;
  38         __be16 protocol;
  39 }__packed;
  40
  41
  42 struct cisco_packet {
  43         __be32 type;            /* code */
  44         __be32 par1;
  45         __be32 par2;
  46         __be16 rel;             /* reliability */
  47         __be32 time;
  48 }__packed;
  49 #define CISCO_PACKET_LEN        18
  50 #define CISCO_BIG_PACKET_LEN    20
  51
  52
  53 struct cisco_state {
  54         cisco_proto settings;
  55
  56         struct timer_list timer;
  57         spinlock_t lock;
  58         unsigned long last_poll;
  59         int up;
  60         u32 txseq; /* TX sequence number, 0 = none */
  61         u32 rxseq; /* RX sequence number */
  62 };
  63
  64
  65 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
  66
  67
  68 static inline struct cisco_state* state(hdlc_device *hdlc)
  69 {
  70         return (struct cisco_state *)hdlc->state;
  71 }
  72
  73
  74 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
  75                              u16 type, const void *daddr, const void *saddr,
  76                              unsigned int len)
  77 {
  78         struct hdlc_header *data;
  79 #ifdef DEBUG_HARD_HEADER
  80         printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name);
  81 #endif
  82
  83         skb_push(skb, sizeof(struct hdlc_header));
  84         data = (struct hdlc_header*)skb->data;
  85         if (type == CISCO_KEEPALIVE)
  86                 data->address = CISCO_MULTICAST;
  87         else
  88                 data->address = CISCO_UNICAST;
  89         data->control = 0;
  90         data->protocol = htons(type);
  91
  92         return sizeof(struct hdlc_header);
  93 }
  94
  95
  96
  97 static void cisco_keepalive_send(struct net_device *dev, u32 type,
  98                                  __be32 par1, __be32 par2)
  99 {
 100         struct sk_buff *skb;
 101         struct cisco_packet *data;
 102
 103         skb = dev_alloc_skb(sizeof(struct hdlc_header) +
 104                             sizeof(struct cisco_packet));
 105         if (!skb) {
 106                 printk(KERN_WARNING
 107                        "%s: Memory squeeze on cisco_keepalive_send()\n",
 108                        dev->name);
 109                 return;
 110         }
 111         skb_reserve(skb, 4);
 112         cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
 113         data = (struct cisco_packet*)(skb->data + 4);
 114
 115         data->type = htonl(type);
 116         data->par1 = par1;
 117         data->par2 = par2;
 118         data->rel = cpu_to_be16(0xFFFF);
 119         /* we will need do_div here if 1000 % HZ != 0 */
 120         data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 121
 122         skb_put(skb, sizeof(struct cisco_packet));
 123         skb->priority = TC_PRIO_CONTROL;
 124         skb->dev = dev;
 125         skb_reset_network_header(skb);
 126
 127         dev_queue_xmit(skb);
 128 }
 129
 130
 131
 132 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 133 {
 134         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 135
 136         if (skb->len < sizeof(struct hdlc_header))
 137                 return cpu_to_be16(ETH_P_HDLC);
 138
 139         if (data->address != CISCO_MULTICAST &&
 140             data->address != CISCO_UNICAST)
 141                 return cpu_to_be16(ETH_P_HDLC);
 142
 143         switch (data->protocol) {
 144         case cpu_to_be16(ETH_P_IP):
 145         case cpu_to_be16(ETH_P_IPX):
 146         case cpu_to_be16(ETH_P_IPV6):
 147                 skb_pull(skb, sizeof(struct hdlc_header));
 148                 return data->protocol;
 149         default:
 150                 return cpu_to_be16(ETH_P_HDLC);
 151         }
 152 }
 153
 154
 155 static int cisco_rx(struct sk_buff *skb)
 156 {
 157         struct net_device *dev = skb->dev;
 158         hdlc_device *hdlc = dev_to_hdlc(dev);
 159         struct cisco_state *st = state(hdlc);
 160         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 161         struct cisco_packet *cisco_data;
 162         struct in_device *in_dev;
 163         __be32 addr, mask;
 164         u32 ack;
 165
 166         if (skb->len < sizeof(struct hdlc_header))
 167                 goto rx_error;
 168
 169         if (data->address != CISCO_MULTICAST &&
 170             data->address != CISCO_UNICAST)
 171                 goto rx_error;
 172
 173         switch (ntohs(data->protocol)) {
 174         case CISCO_SYS_INFO:
 175                 /* Packet is not needed, drop it. */
 176                 dev_kfree_skb_any(skb);
 177                 return NET_RX_SUCCESS;
 178
 179         case CISCO_KEEPALIVE:
 180                 if ((skb->len != sizeof(struct hdlc_header) +
 181                      CISCO_PACKET_LEN) &&
 182                     (skb->len != sizeof(struct hdlc_header) +
 183                      CISCO_BIG_PACKET_LEN)) {
 184                         printk(KERN_INFO "%s: Invalid length of Cisco control"
 185                                " packet (%d bytes)\n", dev->name, skb->len);
 186                         goto rx_error;
 187                 }
 188
 189                 cisco_data = (struct cisco_packet*)(skb->data + sizeof
 190                                                     (struct hdlc_header));
 191
 192                 switch (ntohl (cisco_data->type)) {
 193                 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
 194                         rcu_read_lock();
 195                         in_dev = __in_dev_get_rcu(dev);
 196                         addr = 0;
 197                         mask = ~cpu_to_be32(0); /* is the mask correct? */
 198
 199                         if (in_dev != NULL) {
 200                                 struct in_ifaddr **ifap = &in_dev->ifa_list;
 201
 202                                 while (*ifap != NULL) {
 203                                         if (strcmp(dev->name,
 204                                                    (*ifap)->ifa_label) == 0) {
 205                                                 addr = (*ifap)->ifa_local;
 206                                                 mask = (*ifap)->ifa_mask;
 207                                                 break;
 208                                         }
 209                                         ifap = &(*ifap)->ifa_next;
 210                                 }
 211
 212                                 cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
 213                                                      addr, mask);
 214                         }
 215                         rcu_read_unlock();
 216                         dev_kfree_skb_any(skb);
 217                         return NET_RX_SUCCESS;
 218
 219                 case CISCO_ADDR_REPLY:
 220                         printk(KERN_INFO "%s: Unexpected Cisco IP address "
 221                                "reply\n", dev->name);
 222                         goto rx_error;
 223
 224                 case CISCO_KEEPALIVE_REQ:
 225                         spin_lock(&st->lock);
 226                         st->rxseq = ntohl(cisco_data->par1);
 227                         ack = ntohl(cisco_data->par2);
 228                         if (ack && (ack == st->txseq ||
 229                                     /* our current REQ may be in transit */
 230                                     ack == st->txseq - 1)) {
 231                                 st->last_poll = jiffies;
 232                                 if (!st->up) {
 233                                         u32 sec, min, hrs, days;
 234                                         sec = ntohl(cisco_data->time) / 1000;
 235                                         min = sec / 60; sec -= min * 60;
 236                                         hrs = min / 60; min -= hrs * 60;
 237                                         days = hrs / 24; hrs -= days * 24;
 238                                         printk(KERN_INFO "%s: Link up (peer "
 239                                                "uptime %ud%uh%um%us)\n",
 240                                                dev->name, days, hrs, min, sec);
 241                                         netif_dormant_off(dev);
 242                                         st->up = 1;
 243                                 }
 244                         }
 245                         spin_unlock(&st->lock);
 246
 247                         dev_kfree_skb_any(skb);
 248                         return NET_RX_SUCCESS;
 249                 } /* switch (keepalive type) */
 250         } /* switch (protocol) */
 251
 252         printk(KERN_INFO "%s: Unsupported protocol %x\n", dev->name,
 253                ntohs(data->protocol));
 254         dev_kfree_skb_any(skb);
 255         return NET_RX_DROP;
 256
 257 rx_error:
 258         dev->stats.rx_errors++; /* Mark error */
 259         dev_kfree_skb_any(skb);
 260         return NET_RX_DROP;
 261 }
 262
 263
 264
 265 static void cisco_timer(unsigned long arg)
 266 {
 267         struct net_device *dev = (struct net_device *)arg;
 268         hdlc_device *hdlc = dev_to_hdlc(dev);
 269         struct cisco_state *st = state(hdlc);
 270
 271         spin_lock(&st->lock);
 272         if (st->up &&
 273             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 274                 st->up = 0;
 275                 printk(KERN_INFO "%s: Link down\n", dev->name);
 276                 netif_dormant_on(dev);
 277         }
 278
 279         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 280                              htonl(st->rxseq));
 281         spin_unlock(&st->lock);
 282
 283         st->timer.expires = jiffies + st->settings.interval * HZ;
 284         st->timer.function = cisco_timer;
 285         st->timer.data = arg;
 286         add_timer(&st->timer);
 287 }
 288
 289
 290
 291 static void cisco_start(struct net_device *dev)
 292 {
 293         hdlc_device *hdlc = dev_to_hdlc(dev);
 294         struct cisco_state *st = state(hdlc);
 295         unsigned long flags;
 296
 297         spin_lock_irqsave(&st->lock, flags);
 298         st->up = st->txseq = st->rxseq = 0;
 299         spin_unlock_irqrestore(&st->lock, flags);
 300
 301         init_timer(&st->timer);
 302         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 303         st->timer.function = cisco_timer;
 304         st->timer.data = (unsigned long)dev;
 305         add_timer(&st->timer);
 306 }
 307
 308
 309
 310 static void cisco_stop(struct net_device *dev)
 311 {
 312         hdlc_device *hdlc = dev_to_hdlc(dev);
 313         struct cisco_state *st = state(hdlc);
 314         unsigned long flags;
 315
 316         del_timer_sync(&st->timer);
 317
 318         spin_lock_irqsave(&st->lock, flags);
 319         netif_dormant_on(dev);
 320         st->up = st->txseq = 0;
 321         spin_unlock_irqrestore(&st->lock, flags);
 322 }
 323
 324
 325 static struct hdlc_proto proto = {
 326         .start          = cisco_start,
 327         .stop           = cisco_stop,
 328         .type_trans     = cisco_type_trans,
 329         .ioctl          = cisco_ioctl,
 330         .netif_rx       = cisco_rx,
 331         .module         = THIS_MODULE,
 332 };
 333
 334 static const struct header_ops cisco_header_ops = {
 335         .create = cisco_hard_header,
 336 };
 337
 338 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 339 {
 340         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 341         const size_t size = sizeof(cisco_proto);
 342         cisco_proto new_settings;
 343         hdlc_device *hdlc = dev_to_hdlc(dev);
 344         int result;
 345
 346         switch (ifr->ifr_settings.type) {
 347         case IF_GET_PROTO:
 348                 if (dev_to_hdlc(dev)->proto != &proto)
 349                         return -EINVAL;
 350                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 351                 if (ifr->ifr_settings.size < size) {
 352                         ifr->ifr_settings.size = size; /* data size wanted */
 353                         return -ENOBUFS;
 354                 }
 355                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 356                         return -EFAULT;
 357                 return 0;
 358
 359         case IF_PROTO_CISCO:
 360                 if (!capable(CAP_NET_ADMIN))
 361                         return -EPERM;
 362
 363                 if (dev->flags & IFF_UP)
 364                         return -EBUSY;
 365
 366                 if (copy_from_user(&new_settings, cisco_s, size))
 367                         return -EFAULT;
 368
 369                 if (new_settings.interval < 1 ||
 370                     new_settings.timeout < 2)
 371                         return -EINVAL;
 372
 373                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 374                 if (result)
 375                         return result;
 376
 377                 result = attach_hdlc_protocol(dev, &proto,
 378                                               sizeof(struct cisco_state));
 379                 if (result)
 380                         return result;
 381
 382                 memcpy(&state(hdlc)->settings, &new_settings, size);
 383                 spin_lock_init(&state(hdlc)->lock);
 384                 dev->header_ops = &cisco_header_ops;
 385                 dev->type = ARPHRD_CISCO;
 386                 netif_dormant_on(dev);
 387                 return 0;
 388         }
 389
 390         return -EINVAL;
 391 }
 392
 393
 394 static int __init mod_init(void)
 395 {
 396         register_hdlc_protocol(&proto);
 397         return 0;
 398 }
 399
 400
 401
 402 static void __exit mod_exit(void)
 403 {
 404         unregister_hdlc_protocol(&proto);
 405 }
 406
 407
 408 module_init(mod_init);
 409 module_exit(mod_exit);
 410
 411 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 412 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 413 MODULE_LICENSE("GPL v2");