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         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 = __constant_htons(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 __constant_htons(ETH_P_HDLC);
 140
 141         if (data->address != CISCO_MULTICAST &&
 142             data->address != CISCO_UNICAST)
 143                 return __constant_htons(ETH_P_HDLC);
 144
 145         switch(data->protocol) {
 146         case __constant_htons(ETH_P_IP):
 147         case __constant_htons(ETH_P_IPX):
 148         case __constant_htons(ETH_P_IPV6):
 149                 skb_pull(skb, sizeof(struct hdlc_header));
 150                 return data->protocol;
 151         default:
 152                 return __constant_htons(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 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
 166         if (skb->len < sizeof(struct hdlc_header))
 167                 goto rx_error;
 168
 169         if (data->address != CISCO_MULTICAST &&
 170             data->address != CISCO_UNICAST)
 171                 goto rx_error;
 172
 173         switch(ntohs(data->protocol)) {
 174         case CISCO_SYS_INFO:
 175                 /* Packet is not needed, drop it. */
 176                 dev_kfree_skb_any(skb);
 177                 return NET_RX_SUCCESS;
 178
 179         case CISCO_KEEPALIVE:
 180                 if ((skb->len != sizeof(struct hdlc_header) +
 181                      CISCO_PACKET_LEN) &&
 182                     (skb->len != sizeof(struct hdlc_header) +
 183                      CISCO_BIG_PACKET_LEN)) {
 184                         printk(KERN_INFO "%s: Invalid length of Cisco control"
 185                                " packet (%d bytes)\n", dev->name, skb->len);
 186                         goto rx_error;
 187                 }
 188
 189                 cisco_data = (struct cisco_packet*)(skb->data + sizeof
 190                                                     (struct hdlc_header));
 191
 192                 switch(ntohl (cisco_data->type)) {
 193                 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
 194                         in_dev = dev->ip_ptr;
 195                         addr = 0;
 196                         mask = __constant_htonl(~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                         dev_kfree_skb_any(skb);
 215                         return NET_RX_SUCCESS;
 216
 217                 case CISCO_ADDR_REPLY:
 218                         printk(KERN_INFO "%s: Unexpected Cisco IP address "
 219                                "reply\n", dev->name);
 220                         goto rx_error;
 221
 222                 case CISCO_KEEPALIVE_REQ:
 223                         state(hdlc)->rxseq = ntohl(cisco_data->par1);
 224                         if (state(hdlc)->request_sent &&
 225                             ntohl(cisco_data->par2) == state(hdlc)->txseq) {
 226                                 state(hdlc)->last_poll = jiffies;
 227                                 if (!state(hdlc)->up) {
 228                                         u32 sec, min, hrs, days;
 229                                         sec = ntohl(cisco_data->time) / 1000;
 230                                         min = sec / 60; sec -= min * 60;
 231                                         hrs = min / 60; min -= hrs * 60;
 232                                         days = hrs / 24; hrs -= days * 24;
 233                                         printk(KERN_INFO "%s: Link up (peer "
 234                                                "uptime %ud%uh%um%us)\n",
 235                                                dev->name, days, hrs,
 236                                                min, sec);
 237                                         netif_dormant_off(dev);
 238                                         state(hdlc)->up = 1;
 239                                 }
 240                         }
 241
 242                         dev_kfree_skb_any(skb);
 243                         return NET_RX_SUCCESS;
 244                 } /* switch(keepalive type) */
 245         } /* switch(protocol) */
 246
 247         printk(KERN_INFO "%s: Unsupported protocol %x\n", dev->name,
 248                ntohs(data->protocol));
 249         dev_kfree_skb_any(skb);
 250         return NET_RX_DROP;
 251
 252  rx_error:
 253         dev_to_hdlc(dev)->stats.rx_errors++; /* Mark error */
 254         dev_kfree_skb_any(skb);
 255         return NET_RX_DROP;
 256 }
 257
 258
 259
 260 static void cisco_timer(unsigned long arg)
 261 {
 262         struct net_device *dev = (struct net_device *)arg;
 263         hdlc_device *hdlc = dev_to_hdlc(dev);
 264
 265         if (state(hdlc)->up &&
 266             time_after(jiffies, state(hdlc)->last_poll +
 267                        state(hdlc)->settings.timeout * HZ)) {
 268                 state(hdlc)->up = 0;
 269                 printk(KERN_INFO "%s: Link down\n", dev->name);
 270                 netif_dormant_on(dev);
 271         }
 272
 273         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ,
 274                              htonl(++state(hdlc)->txseq),
 275                              htonl(state(hdlc)->rxseq));
 276         state(hdlc)->request_sent = 1;
 277         state(hdlc)->timer.expires = jiffies +
 278                 state(hdlc)->settings.interval * HZ;
 279         state(hdlc)->timer.function = cisco_timer;
 280         state(hdlc)->timer.data = arg;
 281         add_timer(&state(hdlc)->timer);
 282 }
 283
 284
 285
 286 static void cisco_start(struct net_device *dev)
 287 {
 288         hdlc_device *hdlc = dev_to_hdlc(dev);
 289         state(hdlc)->up = 0;
 290         state(hdlc)->request_sent = 0;
 291         state(hdlc)->txseq = state(hdlc)->rxseq = 0;
 292
 293         init_timer(&state(hdlc)->timer);
 294         state(hdlc)->timer.expires = jiffies + HZ; /*First poll after 1s*/
 295         state(hdlc)->timer.function = cisco_timer;
 296         state(hdlc)->timer.data = (unsigned long)dev;
 297         add_timer(&state(hdlc)->timer);
 298 }
 299
 300
 301
 302 static void cisco_stop(struct net_device *dev)
 303 {
 304         hdlc_device *hdlc = dev_to_hdlc(dev);
 305         del_timer_sync(&state(hdlc)->timer);
 306         netif_dormant_on(dev);
 307         state(hdlc)->up = 0;
 308         state(hdlc)->request_sent = 0;
 309 }
 310
 311
 312 static struct hdlc_proto proto = {
 313         .start          = cisco_start,
 314         .stop           = cisco_stop,
 315         .type_trans     = cisco_type_trans,
 316         .ioctl          = cisco_ioctl,
 317         .netif_rx       = cisco_rx,
 318         .module         = THIS_MODULE,
 319 };
 320
 321 static const struct header_ops cisco_header_ops = {
 322         .create = cisco_hard_header,
 323 };
 324
 325 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 326 {
 327         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 328         const size_t size = sizeof(cisco_proto);
 329         cisco_proto new_settings;
 330         hdlc_device *hdlc = dev_to_hdlc(dev);
 331         int result;
 332
 333         switch (ifr->ifr_settings.type) {
 334         case IF_GET_PROTO:
 335                 if (dev_to_hdlc(dev)->proto != &proto)
 336                         return -EINVAL;
 337                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 338                 if (ifr->ifr_settings.size < size) {
 339                         ifr->ifr_settings.size = size; /* data size wanted */
 340                         return -ENOBUFS;
 341                 }
 342                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 343                         return -EFAULT;
 344                 return 0;
 345
 346         case IF_PROTO_CISCO:
 347                 if(!capable(CAP_NET_ADMIN))
 348                         return -EPERM;
 349
 350                 if(dev->flags & IFF_UP)
 351                         return -EBUSY;
 352
 353                 if (copy_from_user(&new_settings, cisco_s, size))
 354                         return -EFAULT;
 355
 356                 if (new_settings.interval < 1 ||
 357                     new_settings.timeout < 2)
 358                         return -EINVAL;
 359
 360                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 361                 if (result)
 362                         return result;
 363
 364                 result = attach_hdlc_protocol(dev, &proto,
 365                                               sizeof(struct cisco_state));
 366                 if (result)
 367                         return result;
 368
 369                 memcpy(&state(hdlc)->settings, &new_settings, size);
 370                 dev->hard_start_xmit = hdlc->xmit;
 371                 dev->header_ops = &cisco_header_ops;
 372                 dev->type = ARPHRD_CISCO;
 373                 netif_dormant_on(dev);
 374                 return 0;
 375         }
 376
 377         return -EINVAL;
 378 }
 379
 380
 381 static int __init mod_init(void)
 382 {
 383         register_hdlc_protocol(&proto);
 384         return 0;
 385 }
 386
 387
 388
 389 static void __exit mod_exit(void)
 390 {
 391         unregister_hdlc_protocol(&proto);
 392 }
 393
 394
 395 module_init(mod_init);
 396 module_exit(mod_exit);
 397
 398 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 399 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 400 MODULE_LICENSE("GPL v2");