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         struct net_device *dev;
  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                 netdev_warn(dev, "Memory squeeze on cisco_keepalive_send()\n");
 108                 return;
 109         }
 110         skb_reserve(skb, 4);
 111         cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
 112         data = (struct cisco_packet*)(skb->data + 4);
 113
 114         data->type = htonl(type);
 115         data->par1 = par1;
 116         data->par2 = par2;
 117         data->rel = cpu_to_be16(0xFFFF);
 118         /* we will need do_div here if 1000 % HZ != 0 */
 119         data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 120
 121         skb_put(skb, sizeof(struct cisco_packet));
 122         skb->priority = TC_PRIO_CONTROL;
 123         skb->dev = dev;
 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(struct timer_list *t)
 262 {
 263         struct cisco_state *st = from_timer(st, t, timer);
 264         struct net_device *dev = st->dev;
 265
 266         spin_lock(&st->lock);
 267         if (st->up &&
 268             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 269                 st->up = 0;
 270                 netdev_info(dev, "Link down\n");
 271                 netif_dormant_on(dev);
 272         }
 273
 274         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 275                              htonl(st->rxseq));
 276         spin_unlock(&st->lock);
 277
 278         st->timer.expires = jiffies + st->settings.interval * HZ;
 279         add_timer(&st->timer);
 280 }
 281
 282
 283
 284 static void cisco_start(struct net_device *dev)
 285 {
 286         hdlc_device *hdlc = dev_to_hdlc(dev);
 287         struct cisco_state *st = state(hdlc);
 288         unsigned long flags;
 289
 290         spin_lock_irqsave(&st->lock, flags);
 291         st->up = st->txseq = st->rxseq = 0;
 292         spin_unlock_irqrestore(&st->lock, flags);
 293
 294         st->dev = dev;
 295         timer_setup(&st->timer, cisco_timer, 0);
 296         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 297         add_timer(&st->timer);
 298 }
 299
 300
 301
 302 static void cisco_stop(struct net_device *dev)
 303 {
 304         hdlc_device *hdlc = dev_to_hdlc(dev);
 305         struct cisco_state *st = state(hdlc);
 306         unsigned long flags;
 307
 308         del_timer_sync(&st->timer);
 309
 310         spin_lock_irqsave(&st->lock, flags);
 311         netif_dormant_on(dev);
 312         st->up = st->txseq = 0;
 313         spin_unlock_irqrestore(&st->lock, flags);
 314 }
 315
 316
 317 static struct hdlc_proto proto = {
 318         .start          = cisco_start,
 319         .stop           = cisco_stop,
 320         .type_trans     = cisco_type_trans,
 321         .ioctl          = cisco_ioctl,
 322         .netif_rx       = cisco_rx,
 323         .module         = THIS_MODULE,
 324 };
 325
 326 static const struct header_ops cisco_header_ops = {
 327         .create = cisco_hard_header,
 328 };
 329
 330 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 331 {
 332         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 333         const size_t size = sizeof(cisco_proto);
 334         cisco_proto new_settings;
 335         hdlc_device *hdlc = dev_to_hdlc(dev);
 336         int result;
 337
 338         switch (ifr->ifr_settings.type) {
 339         case IF_GET_PROTO:
 340                 if (dev_to_hdlc(dev)->proto != &proto)
 341                         return -EINVAL;
 342                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 343                 if (ifr->ifr_settings.size < size) {
 344                         ifr->ifr_settings.size = size; /* data size wanted */
 345                         return -ENOBUFS;
 346                 }
 347                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 348                         return -EFAULT;
 349                 return 0;
 350
 351         case IF_PROTO_CISCO:
 352                 if (!capable(CAP_NET_ADMIN))
 353                         return -EPERM;
 354
 355                 if (dev->flags & IFF_UP)
 356                         return -EBUSY;
 357
 358                 if (copy_from_user(&new_settings, cisco_s, size))
 359                         return -EFAULT;
 360
 361                 if (new_settings.interval < 1 ||
 362                     new_settings.timeout < 2)
 363                         return -EINVAL;
 364
 365                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 366                 if (result)
 367                         return result;
 368
 369                 result = attach_hdlc_protocol(dev, &proto,
 370                                               sizeof(struct cisco_state));
 371                 if (result)
 372                         return result;
 373
 374                 memcpy(&state(hdlc)->settings, &new_settings, size);
 375                 spin_lock_init(&state(hdlc)->lock);
 376                 dev->header_ops = &cisco_header_ops;
 377                 dev->type = ARPHRD_CISCO;
 378                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 379                 netif_dormant_on(dev);
 380                 return 0;
 381         }
 382
 383         return -EINVAL;
 384 }
 385
 386
 387 static int __init mod_init(void)
 388 {
 389         register_hdlc_protocol(&proto);
 390         return 0;
 391 }
 392
 393
 394
 395 static void __exit mod_exit(void)
 396 {
 397         unregister_hdlc_protocol(&proto);
 398 }
 399
 400
 401 module_init(mod_init);
 402 module_exit(mod_exit);
 403
 404 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 405 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 406 MODULE_LICENSE("GPL v2");