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