drivers/net/wan/hdlc_cisco.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic HDLC support routines for Linux
   4  * Cisco HDLC support
   5  *
   6  * Copyright (C) 2000 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/hdlc.h>
  11 #include <linux/if_arp.h>
  12 #include <linux/inetdevice.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/pkt_sched.h>
  17 #include <linux/poll.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/skbuff.h>
  20
  21 #undef DEBUG_HARD_HEADER
  22
  23 #define CISCO_MULTICAST         0x8F    /* Cisco multicast address */
  24 #define CISCO_UNICAST           0x0F    /* Cisco unicast address */
  25 #define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
  26 #define CISCO_SYS_INFO          0x2000  /* Cisco interface/system info */
  27 #define CISCO_ADDR_REQ          0       /* Cisco address request */
  28 #define CISCO_ADDR_REPLY        1       /* Cisco address reply */
  29 #define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */
  30
  31
  32 struct hdlc_header {
  33         u8 address;
  34         u8 control;
  35         __be16 protocol;
  36 }__packed;
  37
  38
  39 struct cisco_packet {
  40         __be32 type;            /* code */
  41         __be32 par1;
  42         __be32 par2;
  43         __be16 rel;             /* reliability */
  44         __be32 time;
  45 }__packed;
  46 #define CISCO_PACKET_LEN        18
  47 #define CISCO_BIG_PACKET_LEN    20
  48
  49
  50 struct cisco_state {
  51         cisco_proto settings;
  52
  53         struct timer_list timer;
  54         struct net_device *dev;
  55         spinlock_t lock;
  56         unsigned long last_poll;
  57         int up;
  58         u32 txseq; /* TX sequence number, 0 = none */
  59         u32 rxseq; /* RX sequence number */
  60 };
  61
  62
  63 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr);
  64
  65
  66 static inline struct cisco_state* state(hdlc_device *hdlc)
  67 {
  68         return (struct cisco_state *)hdlc->state;
  69 }
  70
  71
  72 static int cisco_hard_header(struct sk_buff *skb, struct net_device *dev,
  73                              u16 type, const void *daddr, const void *saddr,
  74                              unsigned int len)
  75 {
  76         struct hdlc_header *data;
  77 #ifdef DEBUG_HARD_HEADER
  78         netdev_dbg(dev, "%s called\n", __func__);
  79 #endif
  80
  81         skb_push(skb, sizeof(struct hdlc_header));
  82         data = (struct hdlc_header*)skb->data;
  83         if (type == CISCO_KEEPALIVE)
  84                 data->address = CISCO_MULTICAST;
  85         else
  86                 data->address = CISCO_UNICAST;
  87         data->control = 0;
  88         data->protocol = htons(type);
  89
  90         return sizeof(struct hdlc_header);
  91 }
  92
  93
  94
  95 static void cisco_keepalive_send(struct net_device *dev, u32 type,
  96                                  __be32 par1, __be32 par2)
  97 {
  98         struct sk_buff *skb;
  99         struct cisco_packet *data;
 100
 101         skb = dev_alloc_skb(sizeof(struct hdlc_header) +
 102                             sizeof(struct cisco_packet));
 103         if (!skb) {
 104                 netdev_warn(dev, "Memory squeeze on %s()\n", __func__);
 105                 return;
 106         }
 107         skb_reserve(skb, 4);
 108         cisco_hard_header(skb, dev, CISCO_KEEPALIVE, NULL, NULL, 0);
 109         data = (struct cisco_packet*)(skb->data + 4);
 110
 111         data->type = htonl(type);
 112         data->par1 = par1;
 113         data->par2 = par2;
 114         data->rel = cpu_to_be16(0xFFFF);
 115         /* we will need do_div here if 1000 % HZ != 0 */
 116         data->time = htonl((jiffies - INITIAL_JIFFIES) * (1000 / HZ));
 117
 118         skb_put(skb, sizeof(struct cisco_packet));
 119         skb->priority = TC_PRIO_CONTROL;
 120         skb->dev = dev;
 121         skb_reset_network_header(skb);
 122
 123         dev_queue_xmit(skb);
 124 }
 125
 126
 127
 128 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 129 {
 130         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 131
 132         if (skb->len < sizeof(struct hdlc_header))
 133                 return cpu_to_be16(ETH_P_HDLC);
 134
 135         if (data->address != CISCO_MULTICAST &&
 136             data->address != CISCO_UNICAST)
 137                 return cpu_to_be16(ETH_P_HDLC);
 138
 139         switch (data->protocol) {
 140         case cpu_to_be16(ETH_P_IP):
 141         case cpu_to_be16(ETH_P_IPX):
 142         case cpu_to_be16(ETH_P_IPV6):
 143                 skb_pull(skb, sizeof(struct hdlc_header));
 144                 return data->protocol;
 145         default:
 146                 return cpu_to_be16(ETH_P_HDLC);
 147         }
 148 }
 149
 150
 151 static int cisco_rx(struct sk_buff *skb)
 152 {
 153         struct net_device *dev = skb->dev;
 154         hdlc_device *hdlc = dev_to_hdlc(dev);
 155         struct cisco_state *st = state(hdlc);
 156         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 157         struct cisco_packet *cisco_data;
 158         struct in_device *in_dev;
 159         __be32 addr, mask;
 160         u32 ack;
 161
 162         if (skb->len < sizeof(struct hdlc_header))
 163                 goto rx_error;
 164
 165         if (data->address != CISCO_MULTICAST &&
 166             data->address != CISCO_UNICAST)
 167                 goto rx_error;
 168
 169         switch (ntohs(data->protocol)) {
 170         case CISCO_SYS_INFO:
 171                 /* Packet is not needed, drop it. */
 172                 dev_kfree_skb_any(skb);
 173                 return NET_RX_SUCCESS;
 174
 175         case CISCO_KEEPALIVE:
 176                 if ((skb->len != sizeof(struct hdlc_header) +
 177                      CISCO_PACKET_LEN) &&
 178                     (skb->len != sizeof(struct hdlc_header) +
 179                      CISCO_BIG_PACKET_LEN)) {
 180                         netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n",
 181                                     skb->len);
 182                         goto rx_error;
 183                 }
 184
 185                 cisco_data = (struct cisco_packet*)(skb->data + sizeof
 186                                                     (struct hdlc_header));
 187
 188                 switch (ntohl (cisco_data->type)) {
 189                 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
 190                         rcu_read_lock();
 191                         in_dev = __in_dev_get_rcu(dev);
 192                         addr = 0;
 193                         mask = ~cpu_to_be32(0); /* is the mask correct? */
 194
 195                         if (in_dev != NULL) {
 196                                 const struct in_ifaddr *ifa;
 197
 198                                 in_dev_for_each_ifa_rcu(ifa, in_dev) {
 199                                         if (strcmp(dev->name,
 200                                                    ifa->ifa_label) == 0) {
 201                                                 addr = ifa->ifa_local;
 202                                                 mask = ifa->ifa_mask;
 203                                                 break;
 204                                         }
 205                                 }
 206
 207                                 cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
 208                                                      addr, mask);
 209                         }
 210                         rcu_read_unlock();
 211                         dev_kfree_skb_any(skb);
 212                         return NET_RX_SUCCESS;
 213
 214                 case CISCO_ADDR_REPLY:
 215                         netdev_info(dev, "Unexpected Cisco IP address reply\n");
 216                         goto rx_error;
 217
 218                 case CISCO_KEEPALIVE_REQ:
 219                         spin_lock(&st->lock);
 220                         st->rxseq = ntohl(cisco_data->par1);
 221                         ack = ntohl(cisco_data->par2);
 222                         if (ack && (ack == st->txseq ||
 223                                     /* our current REQ may be in transit */
 224                                     ack == st->txseq - 1)) {
 225                                 st->last_poll = jiffies;
 226                                 if (!st->up) {
 227                                         u32 sec, min, hrs, days;
 228                                         sec = ntohl(cisco_data->time) / 1000;
 229                                         min = sec / 60; sec -= min * 60;
 230                                         hrs = min / 60; min -= hrs * 60;
 231                                         days = hrs / 24; hrs -= days * 24;
 232                                         netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n",
 233                                                     days, hrs, min, sec);
 234                                         netif_dormant_off(dev);
 235                                         st->up = 1;
 236                                 }
 237                         }
 238                         spin_unlock(&st->lock);
 239
 240                         dev_kfree_skb_any(skb);
 241                         return NET_RX_SUCCESS;
 242                 } /* switch (keepalive type) */
 243         } /* switch (protocol) */
 244
 245         netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol));
 246         dev_kfree_skb_any(skb);
 247         return NET_RX_DROP;
 248
 249 rx_error:
 250         dev->stats.rx_errors++; /* Mark error */
 251         dev_kfree_skb_any(skb);
 252         return NET_RX_DROP;
 253 }
 254
 255
 256
 257 static void cisco_timer(struct timer_list *t)
 258 {
 259         struct cisco_state *st = from_timer(st, t, timer);
 260         struct net_device *dev = st->dev;
 261
 262         spin_lock(&st->lock);
 263         if (st->up &&
 264             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 265                 st->up = 0;
 266                 netdev_info(dev, "Link down\n");
 267                 netif_dormant_on(dev);
 268         }
 269
 270         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 271                              htonl(st->rxseq));
 272         spin_unlock(&st->lock);
 273
 274         st->timer.expires = jiffies + st->settings.interval * HZ;
 275         add_timer(&st->timer);
 276 }
 277
 278
 279
 280 static void cisco_start(struct net_device *dev)
 281 {
 282         hdlc_device *hdlc = dev_to_hdlc(dev);
 283         struct cisco_state *st = state(hdlc);
 284         unsigned long flags;
 285
 286         spin_lock_irqsave(&st->lock, flags);
 287         st->up = st->txseq = st->rxseq = 0;
 288         spin_unlock_irqrestore(&st->lock, flags);
 289
 290         st->dev = dev;
 291         timer_setup(&st->timer, cisco_timer, 0);
 292         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 293         add_timer(&st->timer);
 294 }
 295
 296
 297
 298 static void cisco_stop(struct net_device *dev)
 299 {
 300         hdlc_device *hdlc = dev_to_hdlc(dev);
 301         struct cisco_state *st = state(hdlc);
 302         unsigned long flags;
 303
 304         del_timer_sync(&st->timer);
 305
 306         spin_lock_irqsave(&st->lock, flags);
 307         netif_dormant_on(dev);
 308         st->up = st->txseq = 0;
 309         spin_unlock_irqrestore(&st->lock, flags);
 310 }
 311
 312
 313 static struct hdlc_proto proto = {
 314         .start          = cisco_start,
 315         .stop           = cisco_stop,
 316         .type_trans     = cisco_type_trans,
 317         .ioctl          = cisco_ioctl,
 318         .netif_rx       = cisco_rx,
 319         .module         = THIS_MODULE,
 320 };
 321
 322 static const struct header_ops cisco_header_ops = {
 323         .create = cisco_hard_header,
 324 };
 325
 326 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 327 {
 328         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 329         const size_t size = sizeof(cisco_proto);
 330         cisco_proto new_settings;
 331         hdlc_device *hdlc = dev_to_hdlc(dev);
 332         int result;
 333
 334         switch (ifr->ifr_settings.type) {
 335         case IF_GET_PROTO:
 336                 if (dev_to_hdlc(dev)->proto != &proto)
 337                         return -EINVAL;
 338                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 339                 if (ifr->ifr_settings.size < size) {
 340                         ifr->ifr_settings.size = size; /* data size wanted */
 341                         return -ENOBUFS;
 342                 }
 343                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 344                         return -EFAULT;
 345                 return 0;
 346
 347         case IF_PROTO_CISCO:
 348                 if (!capable(CAP_NET_ADMIN))
 349                         return -EPERM;
 350
 351                 if (dev->flags & IFF_UP)
 352                         return -EBUSY;
 353
 354                 if (copy_from_user(&new_settings, cisco_s, size))
 355                         return -EFAULT;
 356
 357                 if (new_settings.interval < 1 ||
 358                     new_settings.timeout < 2)
 359                         return -EINVAL;
 360
 361                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 362                 if (result)
 363                         return result;
 364
 365                 result = attach_hdlc_protocol(dev, &proto,
 366                                               sizeof(struct cisco_state));
 367                 if (result)
 368                         return result;
 369
 370                 memcpy(&state(hdlc)->settings, &new_settings, size);
 371                 spin_lock_init(&state(hdlc)->lock);
 372                 dev->header_ops = &cisco_header_ops;
 373                 dev->type = ARPHRD_CISCO;
 374                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 375                 netif_dormant_on(dev);
 376                 return 0;
 377         }
 378
 379         return -EINVAL;
 380 }
 381
 382
 383 static int __init mod_init(void)
 384 {
 385         register_hdlc_protocol(&proto);
 386         return 0;
 387 }
 388
 389
 390
 391 static void __exit mod_exit(void)
 392 {
 393         unregister_hdlc_protocol(&proto);
 394 }
 395
 396
 397 module_init(mod_init);
 398 module_exit(mod_exit);
 399
 400 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 401 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 402 MODULE_LICENSE("GPL v2");