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         u32 txseq; /* TX sequence number, 0 = none */
  62         u32 rxseq; /* RX sequence number */
  63 };
  64
  65
  66 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
  67
  68
  69 static inline struct cisco_state* state(hdlc_device *hdlc)
  70 {
  71         return (struct cisco_state *)hdlc->state;
  72 }
  73
  74
  75 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
  76                              u16 type, const void *daddr, const void *saddr,
  77                              unsigned int len)
  78 {
  79         struct hdlc_header *data;
  80 #ifdef DEBUG_HARD_HEADER
  81         printk(KERN_DEBUG "%s: cisco_hard_header called\n", dev->name);
  82 #endif
  83
  84         skb_push(skb, sizeof(struct hdlc_header));
  85         data = (struct hdlc_header*)skb->data;
  86         if (type == CISCO_KEEPALIVE)
  87                 data->address = CISCO_MULTICAST;
  88         else
  89                 data->address = CISCO_UNICAST;
  90         data->control = 0;
  91         data->protocol = htons(type);
  92
  93         return sizeof(struct hdlc_header);
  94 }
  95
  96
  97
  98 static void cisco_keepalive_send(struct net_device *dev, u32 type,
  99                                  __be32 par1, __be32 par2)
 100 {
 101         struct sk_buff *skb;
 102         struct cisco_packet *data;
 103
 104         skb = dev_alloc_skb(sizeof(struct hdlc_header) +
 105                             sizeof(struct cisco_packet));
 106         if (!skb) {
 107                 printk(KERN_WARNING
 108                        "%s: Memory squeeze on cisco_keepalive_send()\n",
 109                        dev->name);
 110                 return;
 111         }
 112         skb_reserve(skb, 4);
 113         cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
 114         data = (struct cisco_packet*)(skb->data + 4);
 115
 116         data->type = htonl(type);
 117         data->par1 = par1;
 118         data->par2 = par2;
 119         data->rel = cpu_to_be16(0xFFFF);
 120         /* we will need do_div here if 1000 % HZ != 0 */
 121         data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 122
 123         skb_put(skb, sizeof(struct cisco_packet));
 124         skb->priority = TC_PRIO_CONTROL;
 125         skb->dev = dev;
 126         skb_reset_network_header(skb);
 127
 128         dev_queue_xmit(skb);
 129 }
 130
 131
 132
 133 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 134 {
 135         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 136
 137         if (skb->len < sizeof(struct hdlc_header))
 138                 return cpu_to_be16(ETH_P_HDLC);
 139
 140         if (data->address != CISCO_MULTICAST &&
 141             data->address != CISCO_UNICAST)
 142                 return cpu_to_be16(ETH_P_HDLC);
 143
 144         switch (data->protocol) {
 145         case cpu_to_be16(ETH_P_IP):
 146         case cpu_to_be16(ETH_P_IPX):
 147         case cpu_to_be16(ETH_P_IPV6):
 148                 skb_pull(skb, sizeof(struct hdlc_header));
 149                 return data->protocol;
 150         default:
 151                 return cpu_to_be16(ETH_P_HDLC);
 152         }
 153 }
 154
 155
 156 static int cisco_rx(struct sk_buff *skb)
 157 {
 158         struct net_device *dev = skb->dev;
 159         hdlc_device *hdlc = dev_to_hdlc(dev);
 160         struct cisco_state *st = state(hdlc);
 161         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 162         struct cisco_packet *cisco_data;
 163         struct in_device *in_dev;
 164         __be32 addr, mask;
 165         u32 ack;
 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                         ack = ntohl(cisco_data->par2);
 227                         if (ack && (ack == st->txseq ||
 228                                     /* our current REQ may be in transit */
 229                                     ack == st->txseq - 1)) {
 230                                 st->last_poll = jiffies;
 231                                 if (!st->up) {
 232                                         u32 sec, min, hrs, days;
 233                                         sec = ntohl(cisco_data->time) / 1000;
 234                                         min = sec / 60; sec -= min * 60;
 235                                         hrs = min / 60; min -= hrs * 60;
 236                                         days = hrs / 24; hrs -= days * 24;
 237                                         printk(KERN_INFO "%s: Link up (peer "
 238                                                "uptime %ud%uh%um%us)\n",
 239                                                dev->name, days, hrs, min, sec);
 240                                         netif_dormant_off(dev);
 241                                         st->up = 1;
 242                                 }
 243                         }
 244                         spin_unlock(&st->lock);
 245
 246                         dev_kfree_skb_any(skb);
 247                         return NET_RX_SUCCESS;
 248                 } /* switch (keepalive type) */
 249         } /* switch (protocol) */
 250
 251         printk(KERN_INFO "%s: Unsupported protocol %x\n", dev->name,
 252                ntohs(data->protocol));
 253         dev_kfree_skb_any(skb);
 254         return NET_RX_DROP;
 255
 256 rx_error:
 257         dev->stats.rx_errors++; /* Mark error */
 258         dev_kfree_skb_any(skb);
 259         return NET_RX_DROP;
 260 }
 261
 262
 263
 264 static void cisco_timer(unsigned long arg)
 265 {
 266         struct net_device *dev = (struct net_device *)arg;
 267         hdlc_device *hdlc = dev_to_hdlc(dev);
 268         struct cisco_state *st = state(hdlc);
 269
 270         spin_lock(&st->lock);
 271         if (st->up &&
 272             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 273                 st->up = 0;
 274                 printk(KERN_INFO "%s: Link down\n", dev->name);
 275                 netif_dormant_on(dev);
 276         }
 277
 278         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 279                              htonl(st->rxseq));
 280         spin_unlock(&st->lock);
 281
 282         st->timer.expires = jiffies + st->settings.interval * HZ;
 283         st->timer.function = cisco_timer;
 284         st->timer.data = arg;
 285         add_timer(&st->timer);
 286 }
 287
 288
 289
 290 static void cisco_start(struct net_device *dev)
 291 {
 292         hdlc_device *hdlc = dev_to_hdlc(dev);
 293         struct cisco_state *st = state(hdlc);
 294         unsigned long flags;
 295
 296         spin_lock_irqsave(&st->lock, flags);
 297         st->up = st->txseq = st->rxseq = 0;
 298         spin_unlock_irqrestore(&st->lock, flags);
 299
 300         init_timer(&st->timer);
 301         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 302         st->timer.function = cisco_timer;
 303         st->timer.data = (unsigned long)dev;
 304         add_timer(&st->timer);
 305 }
 306
 307
 308
 309 static void cisco_stop(struct net_device *dev)
 310 {
 311         hdlc_device *hdlc = dev_to_hdlc(dev);
 312         struct cisco_state *st = state(hdlc);
 313         unsigned long flags;
 314
 315         del_timer_sync(&st->timer);
 316
 317         spin_lock_irqsave(&st->lock, flags);
 318         netif_dormant_on(dev);
 319         st->up = st->txseq = 0;
 320         spin_unlock_irqrestore(&st->lock, flags);
 321 }
 322
 323
 324 static struct hdlc_proto proto = {
 325         .start          = cisco_start,
 326         .stop           = cisco_stop,
 327         .type_trans     = cisco_type_trans,
 328         .ioctl          = cisco_ioctl,
 329         .netif_rx       = cisco_rx,
 330         .module         = THIS_MODULE,
 331 };
 332
 333 static const struct header_ops cisco_header_ops = {
 334         .create = cisco_hard_header,
 335 };
 336
 337 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 338 {
 339         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 340         const size_t size = sizeof(cisco_proto);
 341         cisco_proto new_settings;
 342         hdlc_device *hdlc = dev_to_hdlc(dev);
 343         int result;
 344
 345         switch (ifr->ifr_settings.type) {
 346         case IF_GET_PROTO:
 347                 if (dev_to_hdlc(dev)->proto != &proto)
 348                         return -EINVAL;
 349                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 350                 if (ifr->ifr_settings.size < size) {
 351                         ifr->ifr_settings.size = size; /* data size wanted */
 352                         return -ENOBUFS;
 353                 }
 354                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 355                         return -EFAULT;
 356                 return 0;
 357
 358         case IF_PROTO_CISCO:
 359                 if (!capable(CAP_NET_ADMIN))
 360                         return -EPERM;
 361
 362                 if (dev->flags & IFF_UP)
 363                         return -EBUSY;
 364
 365                 if (copy_from_user(&new_settings, cisco_s, size))
 366                         return -EFAULT;
 367
 368                 if (new_settings.interval < 1 ||
 369                     new_settings.timeout < 2)
 370                         return -EINVAL;
 371
 372                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 373                 if (result)
 374                         return result;
 375
 376                 result = attach_hdlc_protocol(dev, &proto,
 377                                               sizeof(struct cisco_state));
 378                 if (result)
 379                         return result;
 380
 381                 memcpy(&state(hdlc)->settings, &new_settings, size);
 382                 spin_lock_init(&state(hdlc)->lock);
 383                 dev->header_ops = &cisco_header_ops;
 384                 dev->type = ARPHRD_CISCO;
 385                 netif_dormant_on(dev);
 386                 return 0;
 387         }
 388
 389         return -EINVAL;
 390 }
 391
 392
 393 static int __init mod_init(void)
 394 {
 395         register_hdlc_protocol(&proto);
 396         return 0;
 397 }
 398
 399
 400
 401 static void __exit mod_exit(void)
 402 {
 403         unregister_hdlc_protocol(&proto);
 404 }
 405
 406
 407 module_init(mod_init);
 408 module_exit(mod_exit);
 409
 410 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 411 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 412 MODULE_LICENSE("GPL v2");