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