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                 netdev_warn(dev, "Memory squeeze on cisco_keepalive_send()\n");
 107                 return;
 108         }
 109         skb_reserve(skb, 4);
 110         cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
 111         data = (struct cisco_packet*)(skb->data + 4);
 112
 113         data->type = htonl(type);
 114         data->par1 = par1;
 115         data->par2 = par2;
 116         data->rel = cpu_to_be16(0xFFFF);
 117         /* we will need do_div here if 1000 % HZ != 0 */
 118         data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 119
 120         skb_put(skb, sizeof(struct cisco_packet));
 121         skb->priority = TC_PRIO_CONTROL;
 122         skb->dev = dev;
 123         skb->protocol = htons(ETH_P_HDLC);
 124         skb_reset_network_header(skb);
 125
 126         dev_queue_xmit(skb);
 127 }
 128
 129
 130
 131 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 132 {
 133         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 134
 135         if (skb->len < sizeof(struct hdlc_header))
 136                 return cpu_to_be16(ETH_P_HDLC);
 137
 138         if (data->address != CISCO_MULTICAST &&
 139             data->address != CISCO_UNICAST)
 140                 return cpu_to_be16(ETH_P_HDLC);
 141
 142         switch (data->protocol) {
 143         case cpu_to_be16(ETH_P_IP):
 144         case cpu_to_be16(ETH_P_IPX):
 145         case cpu_to_be16(ETH_P_IPV6):
 146                 skb_pull(skb, sizeof(struct hdlc_header));
 147                 return data->protocol;
 148         default:
 149                 return cpu_to_be16(ETH_P_HDLC);
 150         }
 151 }
 152
 153
 154 static int cisco_rx(struct sk_buff *skb)
 155 {
 156         struct net_device *dev = skb->dev;
 157         hdlc_device *hdlc = dev_to_hdlc(dev);
 158         struct cisco_state *st = state(hdlc);
 159         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 160         struct cisco_packet *cisco_data;
 161         struct in_device *in_dev;
 162         __be32 addr, mask;
 163         u32 ack;
 164
 165         if (skb->len < sizeof(struct hdlc_header))
 166                 goto rx_error;
 167
 168         if (data->address != CISCO_MULTICAST &&
 169             data->address != CISCO_UNICAST)
 170                 goto rx_error;
 171
 172         switch (ntohs(data->protocol)) {
 173         case CISCO_SYS_INFO:
 174                 /* Packet is not needed, drop it. */
 175                 dev_kfree_skb_any(skb);
 176                 return NET_RX_SUCCESS;
 177
 178         case CISCO_KEEPALIVE:
 179                 if ((skb->len != sizeof(struct hdlc_header) +
 180                      CISCO_PACKET_LEN) &&
 181                     (skb->len != sizeof(struct hdlc_header) +
 182                      CISCO_BIG_PACKET_LEN)) {
 183                         netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n",
 184                                     skb->len);
 185                         goto rx_error;
 186                 }
 187
 188                 cisco_data = (struct cisco_packet*)(skb->data + sizeof
 189                                                     (struct hdlc_header));
 190
 191                 switch (ntohl (cisco_data->type)) {
 192                 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
 193                         rcu_read_lock();
 194                         in_dev = __in_dev_get_rcu(dev);
 195                         addr = 0;
 196                         mask = ~cpu_to_be32(0); /* is the mask correct? */
 197
 198                         if (in_dev != NULL) {
 199                                 struct in_ifaddr **ifap = &in_dev->ifa_list;
 200
 201                                 while (*ifap != NULL) {
 202                                         if (strcmp(dev->name,
 203                                                    (*ifap)->ifa_label) == 0) {
 204                                                 addr = (*ifap)->ifa_local;
 205                                                 mask = (*ifap)->ifa_mask;
 206                                                 break;
 207                                         }
 208                                         ifap = &(*ifap)->ifa_next;
 209                                 }
 210
 211                                 cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
 212                                                      addr, mask);
 213                         }
 214                         rcu_read_unlock();
 215                         dev_kfree_skb_any(skb);
 216                         return NET_RX_SUCCESS;
 217
 218                 case CISCO_ADDR_REPLY:
 219                         netdev_info(dev, "Unexpected Cisco IP address reply\n");
 220                         goto rx_error;
 221
 222                 case CISCO_KEEPALIVE_REQ:
 223                         spin_lock(&st->lock);
 224                         st->rxseq = ntohl(cisco_data->par1);
 225                         ack = ntohl(cisco_data->par2);
 226                         if (ack && (ack == st->txseq ||
 227                                     /* our current REQ may be in transit */
 228                                     ack == st->txseq - 1)) {
 229                                 st->last_poll = jiffies;
 230                                 if (!st->up) {
 231                                         u32 sec, min, hrs, days;
 232                                         sec = ntohl(cisco_data->time) / 1000;
 233                                         min = sec / 60; sec -= min * 60;
 234                                         hrs = min / 60; min -= hrs * 60;
 235                                         days = hrs / 24; hrs -= days * 24;
 236                                         netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n",
 237                                                     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         netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol));
 250         dev_kfree_skb_any(skb);
 251         return NET_RX_DROP;
 252
 253 rx_error:
 254         dev->stats.rx_errors++; /* Mark error */
 255         dev_kfree_skb_any(skb);
 256         return NET_RX_DROP;
 257 }
 258
 259
 260
 261 static void cisco_timer(unsigned long arg)
 262 {
 263         struct net_device *dev = (struct net_device *)arg;
 264         hdlc_device *hdlc = dev_to_hdlc(dev);
 265         struct cisco_state *st = state(hdlc);
 266
 267         spin_lock(&st->lock);
 268         if (st->up &&
 269             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 270                 st->up = 0;
 271                 netdev_info(dev, "Link down\n");
 272                 netif_dormant_on(dev);
 273         }
 274
 275         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 276                              htonl(st->rxseq));
 277         spin_unlock(&st->lock);
 278
 279         st->timer.expires = jiffies + st->settings.interval * HZ;
 280         st->timer.function = cisco_timer;
 281         st->timer.data = arg;
 282         add_timer(&st->timer);
 283 }
 284
 285
 286
 287 static void cisco_start(struct net_device *dev)
 288 {
 289         hdlc_device *hdlc = dev_to_hdlc(dev);
 290         struct cisco_state *st = state(hdlc);
 291         unsigned long flags;
 292
 293         spin_lock_irqsave(&st->lock, flags);
 294         st->up = st->txseq = st->rxseq = 0;
 295         spin_unlock_irqrestore(&st->lock, flags);
 296
 297         init_timer(&st->timer);
 298         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 299         st->timer.function = cisco_timer;
 300         st->timer.data = (unsigned long)dev;
 301         add_timer(&st->timer);
 302 }
 303
 304
 305
 306 static void cisco_stop(struct net_device *dev)
 307 {
 308         hdlc_device *hdlc = dev_to_hdlc(dev);
 309         struct cisco_state *st = state(hdlc);
 310         unsigned long flags;
 311
 312         del_timer_sync(&st->timer);
 313
 314         spin_lock_irqsave(&st->lock, flags);
 315         netif_dormant_on(dev);
 316         st->up = st->txseq = 0;
 317         spin_unlock_irqrestore(&st->lock, flags);
 318 }
 319
 320
 321 static struct hdlc_proto proto = {
 322         .start          = cisco_start,
 323         .stop           = cisco_stop,
 324         .type_trans     = cisco_type_trans,
 325         .ioctl          = cisco_ioctl,
 326         .netif_rx       = cisco_rx,
 327         .module         = THIS_MODULE,
 328 };
 329
 330 static const struct header_ops cisco_header_ops = {
 331         .create = cisco_hard_header,
 332 };
 333
 334 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 335 {
 336         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 337         const size_t size = sizeof(cisco_proto);
 338         cisco_proto new_settings;
 339         hdlc_device *hdlc = dev_to_hdlc(dev);
 340         int result;
 341
 342         switch (ifr->ifr_settings.type) {
 343         case IF_GET_PROTO:
 344                 if (dev_to_hdlc(dev)->proto != &proto)
 345                         return -EINVAL;
 346                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 347                 if (ifr->ifr_settings.size < size) {
 348                         ifr->ifr_settings.size = size; /* data size wanted */
 349                         return -ENOBUFS;
 350                 }
 351                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 352                         return -EFAULT;
 353                 return 0;
 354
 355         case IF_PROTO_CISCO:
 356                 if (!capable(CAP_NET_ADMIN))
 357                         return -EPERM;
 358
 359                 if (dev->flags & IFF_UP)
 360                         return -EBUSY;
 361
 362                 if (copy_from_user(&new_settings, cisco_s, size))
 363                         return -EFAULT;
 364
 365                 if (new_settings.interval < 1 ||
 366                     new_settings.timeout < 2)
 367                         return -EINVAL;
 368
 369                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 370                 if (result)
 371                         return result;
 372
 373                 result = attach_hdlc_protocol(dev, &proto,
 374                                               sizeof(struct cisco_state));
 375                 if (result)
 376                         return result;
 377
 378                 memcpy(&state(hdlc)->settings, &new_settings, size);
 379                 spin_lock_init(&state(hdlc)->lock);
 380                 dev->header_ops = &cisco_header_ops;
 381                 dev->hard_header_len = sizeof(struct hdlc_header);
 382                 dev->type = ARPHRD_CISCO;
 383                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 384                 netif_dormant_on(dev);
 385                 return 0;
 386         }
 387
 388         return -EINVAL;
 389 }
 390
 391
 392 static int __init mod_init(void)
 393 {
 394         register_hdlc_protocol(&proto);
 395         return 0;
 396 }
 397
 398
 399
 400 static void __exit mod_exit(void)
 401 {
 402         unregister_hdlc_protocol(&proto);
 403 }
 404
 405
 406 module_init(mod_init);
 407 module_exit(mod_exit);
 408
 409 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 410 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 411 MODULE_LICENSE("GPL v2");