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->protocol = htons(ETH_P_HDLC);
 122         skb_reset_network_header(skb);
 123
 124         dev_queue_xmit(skb);
 125 }
 126
 127
 128
 129 static __be16 cisco_type_trans(struct sk_buff *skb, struct net_device *dev)
 130 {
 131         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 132
 133         if (skb->len < sizeof(struct hdlc_header))
 134                 return cpu_to_be16(ETH_P_HDLC);
 135
 136         if (data->address != CISCO_MULTICAST &&
 137             data->address != CISCO_UNICAST)
 138                 return cpu_to_be16(ETH_P_HDLC);
 139
 140         switch (data->protocol) {
 141         case cpu_to_be16(ETH_P_IP):
 142         case cpu_to_be16(ETH_P_IPX):
 143         case cpu_to_be16(ETH_P_IPV6):
 144                 skb_pull(skb, sizeof(struct hdlc_header));
 145                 return data->protocol;
 146         default:
 147                 return cpu_to_be16(ETH_P_HDLC);
 148         }
 149 }
 150
 151
 152 static int cisco_rx(struct sk_buff *skb)
 153 {
 154         struct net_device *dev = skb->dev;
 155         hdlc_device *hdlc = dev_to_hdlc(dev);
 156         struct cisco_state *st = state(hdlc);
 157         struct hdlc_header *data = (struct hdlc_header*)skb->data;
 158         struct cisco_packet *cisco_data;
 159         struct in_device *in_dev;
 160         __be32 addr, mask;
 161         u32 ack;
 162
 163         if (skb->len < sizeof(struct hdlc_header))
 164                 goto rx_error;
 165
 166         if (data->address != CISCO_MULTICAST &&
 167             data->address != CISCO_UNICAST)
 168                 goto rx_error;
 169
 170         switch (ntohs(data->protocol)) {
 171         case CISCO_SYS_INFO:
 172                 /* Packet is not needed, drop it. */
 173                 dev_kfree_skb_any(skb);
 174                 return NET_RX_SUCCESS;
 175
 176         case CISCO_KEEPALIVE:
 177                 if ((skb->len != sizeof(struct hdlc_header) +
 178                      CISCO_PACKET_LEN) &&
 179                     (skb->len != sizeof(struct hdlc_header) +
 180                      CISCO_BIG_PACKET_LEN)) {
 181                         netdev_info(dev, "Invalid length of Cisco control packet (%d bytes)\n",
 182                                     skb->len);
 183                         goto rx_error;
 184                 }
 185
 186                 cisco_data = (struct cisco_packet*)(skb->data + sizeof
 187                                                     (struct hdlc_header));
 188
 189                 switch (ntohl (cisco_data->type)) {
 190                 case CISCO_ADDR_REQ: /* Stolen from syncppp.c :-) */
 191                         rcu_read_lock();
 192                         in_dev = __in_dev_get_rcu(dev);
 193                         addr = 0;
 194                         mask = ~cpu_to_be32(0); /* is the mask correct? */
 195
 196                         if (in_dev != NULL) {
 197                                 const struct in_ifaddr *ifa;
 198
 199                                 in_dev_for_each_ifa_rcu(ifa, in_dev) {
 200                                         if (strcmp(dev->name,
 201                                                    ifa->ifa_label) == 0) {
 202                                                 addr = ifa->ifa_local;
 203                                                 mask = ifa->ifa_mask;
 204                                                 break;
 205                                         }
 206                                 }
 207
 208                                 cisco_keepalive_send(dev, CISCO_ADDR_REPLY,
 209                                                      addr, mask);
 210                         }
 211                         rcu_read_unlock();
 212                         dev_kfree_skb_any(skb);
 213                         return NET_RX_SUCCESS;
 214
 215                 case CISCO_ADDR_REPLY:
 216                         netdev_info(dev, "Unexpected Cisco IP address reply\n");
 217                         goto rx_error;
 218
 219                 case CISCO_KEEPALIVE_REQ:
 220                         spin_lock(&st->lock);
 221                         st->rxseq = ntohl(cisco_data->par1);
 222                         ack = ntohl(cisco_data->par2);
 223                         if (ack && (ack == st->txseq ||
 224                                     /* our current REQ may be in transit */
 225                                     ack == st->txseq - 1)) {
 226                                 st->last_poll = jiffies;
 227                                 if (!st->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                                         netdev_info(dev, "Link up (peer uptime %ud%uh%um%us)\n",
 234                                                     days, hrs, min, sec);
 235                                         netif_dormant_off(dev);
 236                                         st->up = 1;
 237                                 }
 238                         }
 239                         spin_unlock(&st->lock);
 240
 241                         dev_kfree_skb_any(skb);
 242                         return NET_RX_SUCCESS;
 243                 } /* switch (keepalive type) */
 244         } /* switch (protocol) */
 245
 246         netdev_info(dev, "Unsupported protocol %x\n", ntohs(data->protocol));
 247         dev_kfree_skb_any(skb);
 248         return NET_RX_DROP;
 249
 250 rx_error:
 251         dev->stats.rx_errors++; /* Mark error */
 252         dev_kfree_skb_any(skb);
 253         return NET_RX_DROP;
 254 }
 255
 256
 257
 258 static void cisco_timer(struct timer_list *t)
 259 {
 260         struct cisco_state *st = from_timer(st, t, timer);
 261         struct net_device *dev = st->dev;
 262
 263         spin_lock(&st->lock);
 264         if (st->up &&
 265             time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
 266                 st->up = 0;
 267                 netdev_info(dev, "Link down\n");
 268                 netif_dormant_on(dev);
 269         }
 270
 271         cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
 272                              htonl(st->rxseq));
 273         spin_unlock(&st->lock);
 274
 275         st->timer.expires = jiffies + st->settings.interval * HZ;
 276         add_timer(&st->timer);
 277 }
 278
 279
 280
 281 static void cisco_start(struct net_device *dev)
 282 {
 283         hdlc_device *hdlc = dev_to_hdlc(dev);
 284         struct cisco_state *st = state(hdlc);
 285         unsigned long flags;
 286
 287         spin_lock_irqsave(&st->lock, flags);
 288         st->up = st->txseq = st->rxseq = 0;
 289         spin_unlock_irqrestore(&st->lock, flags);
 290
 291         st->dev = dev;
 292         timer_setup(&st->timer, cisco_timer, 0);
 293         st->timer.expires = jiffies + HZ; /* First poll after 1 s */
 294         add_timer(&st->timer);
 295 }
 296
 297
 298
 299 static void cisco_stop(struct net_device *dev)
 300 {
 301         hdlc_device *hdlc = dev_to_hdlc(dev);
 302         struct cisco_state *st = state(hdlc);
 303         unsigned long flags;
 304
 305         del_timer_sync(&st->timer);
 306
 307         spin_lock_irqsave(&st->lock, flags);
 308         netif_dormant_on(dev);
 309         st->up = st->txseq = 0;
 310         spin_unlock_irqrestore(&st->lock, flags);
 311 }
 312
 313
 314 static struct hdlc_proto proto = {
 315         .start          = cisco_start,
 316         .stop           = cisco_stop,
 317         .type_trans     = cisco_type_trans,
 318         .ioctl          = cisco_ioctl,
 319         .netif_rx       = cisco_rx,
 320         .module         = THIS_MODULE,
 321 };
 322
 323 static const struct header_ops cisco_header_ops = {
 324         .create = cisco_hard_header,
 325 };
 326
 327 static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
 328 {
 329         cisco_proto __user *cisco_s = ifr->ifr_settings.ifs_ifsu.cisco;
 330         const size_t size = sizeof(cisco_proto);
 331         cisco_proto new_settings;
 332         hdlc_device *hdlc = dev_to_hdlc(dev);
 333         int result;
 334
 335         switch (ifr->ifr_settings.type) {
 336         case IF_GET_PROTO:
 337                 if (dev_to_hdlc(dev)->proto != &proto)
 338                         return -EINVAL;
 339                 ifr->ifr_settings.type = IF_PROTO_CISCO;
 340                 if (ifr->ifr_settings.size < size) {
 341                         ifr->ifr_settings.size = size; /* data size wanted */
 342                         return -ENOBUFS;
 343                 }
 344                 if (copy_to_user(cisco_s, &state(hdlc)->settings, size))
 345                         return -EFAULT;
 346                 return 0;
 347
 348         case IF_PROTO_CISCO:
 349                 if (!capable(CAP_NET_ADMIN))
 350                         return -EPERM;
 351
 352                 if (dev->flags & IFF_UP)
 353                         return -EBUSY;
 354
 355                 if (copy_from_user(&new_settings, cisco_s, size))
 356                         return -EFAULT;
 357
 358                 if (new_settings.interval < 1 ||
 359                     new_settings.timeout < 2)
 360                         return -EINVAL;
 361
 362                 result = hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 363                 if (result)
 364                         return result;
 365
 366                 result = attach_hdlc_protocol(dev, &proto,
 367                                               sizeof(struct cisco_state));
 368                 if (result)
 369                         return result;
 370
 371                 memcpy(&state(hdlc)->settings, &new_settings, size);
 372                 spin_lock_init(&state(hdlc)->lock);
 373                 dev->header_ops = &cisco_header_ops;
 374                 dev->hard_header_len = sizeof(struct hdlc_header);
 375                 dev->type = ARPHRD_CISCO;
 376                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 377                 netif_dormant_on(dev);
 378                 return 0;
 379         }
 380
 381         return -EINVAL;
 382 }
 383
 384
 385 static int __init mod_init(void)
 386 {
 387         register_hdlc_protocol(&proto);
 388         return 0;
 389 }
 390
 391
 392
 393 static void __exit mod_exit(void)
 394 {
 395         unregister_hdlc_protocol(&proto);
 396 }
 397
 398
 399 module_init(mod_init);
 400 module_exit(mod_exit);
 401
 402 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 403 MODULE_DESCRIPTION("Cisco HDLC protocol support for generic HDLC");
 404 MODULE_LICENSE("GPL v2");