linux/drivers/net/wan/dlci.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * DLCI         Implementation of Frame Relay protocol for Linux, according to
   4 *              RFC 1490.  This generic device provides en/decapsulation for an
   5 *              underlying hardware driver.  Routes & IPs are assigned to these
   6 *              interfaces.  Requires 'dlcicfg' program to create usable 
   7 *              interfaces, the initial one, 'dlci' is for IOCTL use only.
   8 *
   9 * Version:     @(#)dlci.c      0.35    4 Jan 1997
  10 *
  11 * Author:      Mike McLagan <mike.mclagan@linux.org>
  12 *
  13 * Changes:
  14 *
  15 *              0.15    Mike Mclagan    Packet freeing, bug in kmalloc call
  16 *                                      DLCI_RET handling
  17 *              0.20    Mike McLagan    More conservative on which packets
  18 *                                      are returned for retry and which are
  19 *                                      are dropped.  If DLCI_RET_DROP is
  20 *                                      returned from the FRAD, the packet is
  21 *                                      sent back to Linux for re-transmission
  22 *              0.25    Mike McLagan    Converted to use SIOC IOCTL calls
  23 *              0.30    Jim Freeman     Fixed to allow IPX traffic
  24 *              0.35    Michael Elizabeth       Fixed incorrect memcpy_fromfs
  25 */
  26
  27#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  28
  29#include <linux/module.h>
  30#include <linux/kernel.h>
  31#include <linux/types.h>
  32#include <linux/fcntl.h>
  33#include <linux/interrupt.h>
  34#include <linux/ptrace.h>
  35#include <linux/ioport.h>
  36#include <linux/in.h>
  37#include <linux/init.h>
  38#include <linux/slab.h>
  39#include <linux/string.h>
  40#include <linux/errno.h>
  41#include <linux/netdevice.h>
  42#include <linux/skbuff.h>
  43#include <linux/if_arp.h>
  44#include <linux/if_frad.h>
  45#include <linux/bitops.h>
  46
  47#include <net/sock.h>
  48
  49#include <asm/io.h>
  50#include <asm/dma.h>
  51#include <linux/uaccess.h>
  52
  53static const char version[] = "DLCI driver v0.35, 4 Jan 1997, mike.mclagan@linux.org";
  54
  55static LIST_HEAD(dlci_devs);
  56
  57static void dlci_setup(struct net_device *);
  58
  59/* 
  60 * these encapsulate the RFC 1490 requirements as well as 
  61 * deal with packet transmission and reception, working with
  62 * the upper network layers 
  63 */
  64
  65static int dlci_header(struct sk_buff *skb, struct net_device *dev, 
  66                       unsigned short type, const void *daddr,
  67                       const void *saddr, unsigned len)
  68{
  69        struct frhdr            hdr;
  70        unsigned int            hlen;
  71        char                    *dest;
  72
  73        hdr.control = FRAD_I_UI;
  74        switch (type)
  75        {
  76                case ETH_P_IP:
  77                        hdr.IP_NLPID = FRAD_P_IP;
  78                        hlen = sizeof(hdr.control) + sizeof(hdr.IP_NLPID);
  79                        break;
  80
  81                /* feel free to add other types, if necessary */
  82
  83                default:
  84                        hdr.pad = FRAD_P_PADDING;
  85                        hdr.NLPID = FRAD_P_SNAP;
  86                        memset(hdr.OUI, 0, sizeof(hdr.OUI));
  87                        hdr.PID = htons(type);
  88                        hlen = sizeof(hdr);
  89                        break;
  90        }
  91
  92        dest = skb_push(skb, hlen);
  93        if (!dest)
  94                return 0;
  95
  96        memcpy(dest, &hdr, hlen);
  97
  98        return hlen;
  99}
 100
 101static void dlci_receive(struct sk_buff *skb, struct net_device *dev)
 102{
 103        struct frhdr            *hdr;
 104        int                                     process, header;
 105
 106        if (!pskb_may_pull(skb, sizeof(*hdr))) {
 107                netdev_notice(dev, "invalid data no header\n");
 108                dev->stats.rx_errors++;
 109                kfree_skb(skb);
 110                return;
 111        }
 112
 113        hdr = (struct frhdr *) skb->data;
 114        process = 0;
 115        header = 0;
 116        skb->dev = dev;
 117
 118        if (hdr->control != FRAD_I_UI)
 119        {
 120                netdev_notice(dev, "Invalid header flag 0x%02X\n",
 121                              hdr->control);
 122                dev->stats.rx_errors++;
 123        }
 124        else
 125                switch (hdr->IP_NLPID)
 126                {
 127                        case FRAD_P_PADDING:
 128                                if (hdr->NLPID != FRAD_P_SNAP)
 129                                {
 130                                        netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
 131                                                      hdr->NLPID);
 132                                        dev->stats.rx_errors++;
 133                                        break;
 134                                }
 135         
 136                                if (hdr->OUI[0] + hdr->OUI[1] + hdr->OUI[2] != 0)
 137                                {
 138                                        netdev_notice(dev, "Unsupported organizationally unique identifier 0x%02X-%02X-%02X\n",
 139                                                      hdr->OUI[0],
 140                                                      hdr->OUI[1],
 141                                                      hdr->OUI[2]);
 142                                        dev->stats.rx_errors++;
 143                                        break;
 144                                }
 145
 146                                /* at this point, it's an EtherType frame */
 147                                header = sizeof(struct frhdr);
 148                                /* Already in network order ! */
 149                                skb->protocol = hdr->PID;
 150                                process = 1;
 151                                break;
 152
 153                        case FRAD_P_IP:
 154                                header = sizeof(hdr->control) + sizeof(hdr->IP_NLPID);
 155                                skb->protocol = htons(ETH_P_IP);
 156                                process = 1;
 157                                break;
 158
 159                        case FRAD_P_SNAP:
 160                        case FRAD_P_Q933:
 161                        case FRAD_P_CLNP:
 162                                netdev_notice(dev, "Unsupported NLPID 0x%02X\n",
 163                                              hdr->pad);
 164                                dev->stats.rx_errors++;
 165                                break;
 166
 167                        default:
 168                                netdev_notice(dev, "Invalid pad byte 0x%02X\n",
 169                                              hdr->pad);
 170                                dev->stats.rx_errors++;
 171                                break;                          
 172                }
 173
 174        if (process)
 175        {
 176                /* we've set up the protocol, so discard the header */
 177                skb_reset_mac_header(skb);
 178                skb_pull(skb, header);
 179                dev->stats.rx_bytes += skb->len;
 180                netif_rx(skb);
 181                dev->stats.rx_packets++;
 182        }
 183        else
 184                dev_kfree_skb(skb);
 185}
 186
 187static netdev_tx_t dlci_transmit(struct sk_buff *skb, struct net_device *dev)
 188{
 189        struct dlci_local *dlp = netdev_priv(dev);
 190
 191        if (skb) {
 192                struct netdev_queue *txq = skb_get_tx_queue(dev, skb);
 193                netdev_start_xmit(skb, dlp->slave, txq, false);
 194        }
 195        return NETDEV_TX_OK;
 196}
 197
 198static int dlci_config(struct net_device *dev, struct dlci_conf __user *conf, int get)
 199{
 200        struct dlci_conf        config;
 201        struct dlci_local       *dlp;
 202        struct frad_local       *flp;
 203        int                     err;
 204
 205        dlp = netdev_priv(dev);
 206
 207        flp = netdev_priv(dlp->slave);
 208
 209        if (!get)
 210        {
 211                if (copy_from_user(&config, conf, sizeof(struct dlci_conf)))
 212                        return -EFAULT;
 213                if (config.flags & ~DLCI_VALID_FLAGS)
 214                        return -EINVAL;
 215                memcpy(&dlp->config, &config, sizeof(struct dlci_conf));
 216                dlp->configured = 1;
 217        }
 218
 219        err = (*flp->dlci_conf)(dlp->slave, dev, get);
 220        if (err)
 221                return err;
 222
 223        if (get)
 224        {
 225                if (copy_to_user(conf, &dlp->config, sizeof(struct dlci_conf)))
 226                        return -EFAULT;
 227        }
 228
 229        return 0;
 230}
 231
 232static int dlci_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 233{
 234        struct dlci_local *dlp;
 235
 236        if (!capable(CAP_NET_ADMIN))
 237                return -EPERM;
 238
 239        dlp = netdev_priv(dev);
 240
 241        switch (cmd)
 242        {
 243                case DLCI_GET_SLAVE:
 244                        if (!*(short *)(dev->dev_addr))
 245                                return -EINVAL;
 246
 247                        strncpy(ifr->ifr_slave, dlp->slave->name, sizeof(ifr->ifr_slave));
 248                        break;
 249
 250                case DLCI_GET_CONF:
 251                case DLCI_SET_CONF:
 252                        if (!*(short *)(dev->dev_addr))
 253                                return -EINVAL;
 254
 255                        return dlci_config(dev, ifr->ifr_data, cmd == DLCI_GET_CONF);
 256
 257                default: 
 258                        return -EOPNOTSUPP;
 259        }
 260        return 0;
 261}
 262
 263static int dlci_change_mtu(struct net_device *dev, int new_mtu)
 264{
 265        struct dlci_local *dlp = netdev_priv(dev);
 266
 267        return dev_set_mtu(dlp->slave, new_mtu);
 268}
 269
 270static int dlci_open(struct net_device *dev)
 271{
 272        struct dlci_local       *dlp;
 273        struct frad_local       *flp;
 274        int                     err;
 275
 276        dlp = netdev_priv(dev);
 277
 278        if (!*(short *)(dev->dev_addr))
 279                return -EINVAL;
 280
 281        if (!netif_running(dlp->slave))
 282                return -ENOTCONN;
 283
 284        flp = netdev_priv(dlp->slave);
 285        err = (*flp->activate)(dlp->slave, dev);
 286        if (err)
 287                return err;
 288
 289        netif_start_queue(dev);
 290
 291        return 0;
 292}
 293
 294static int dlci_close(struct net_device *dev)
 295{
 296        struct dlci_local       *dlp;
 297        struct frad_local       *flp;
 298
 299        netif_stop_queue(dev);
 300
 301        dlp = netdev_priv(dev);
 302
 303        flp = netdev_priv(dlp->slave);
 304        (*flp->deactivate)(dlp->slave, dev);
 305
 306        return 0;
 307}
 308
 309static int dlci_add(struct dlci_add *dlci)
 310{
 311        struct net_device       *master, *slave;
 312        struct dlci_local       *dlp;
 313        struct frad_local       *flp;
 314        int                     err = -EINVAL;
 315
 316
 317        /* validate slave device */
 318        slave = dev_get_by_name(&init_net, dlci->devname);
 319        if (!slave)
 320                return -ENODEV;
 321
 322        if (slave->type != ARPHRD_FRAD || netdev_priv(slave) == NULL)
 323                goto err1;
 324
 325        /* create device name */
 326        master = alloc_netdev(sizeof(struct dlci_local), "dlci%d",
 327                              NET_NAME_UNKNOWN, dlci_setup);
 328        if (!master) {
 329                err = -ENOMEM;
 330                goto err1;
 331        }
 332
 333        /* make sure same slave not already registered */
 334        rtnl_lock();
 335        list_for_each_entry(dlp, &dlci_devs, list) {
 336                if (dlp->slave == slave) {
 337                        err = -EBUSY;
 338                        goto err2;
 339                }
 340        }
 341
 342        *(short *)(master->dev_addr) = dlci->dlci;
 343
 344        dlp = netdev_priv(master);
 345        dlp->slave = slave;
 346        dlp->master = master;
 347
 348        flp = netdev_priv(slave);
 349        err = (*flp->assoc)(slave, master);
 350        if (err < 0)
 351                goto err2;
 352
 353        err = register_netdevice(master);
 354        if (err < 0) 
 355                goto err2;
 356
 357        strcpy(dlci->devname, master->name);
 358
 359        list_add(&dlp->list, &dlci_devs);
 360        rtnl_unlock();
 361
 362        return 0;
 363
 364 err2:
 365        rtnl_unlock();
 366        free_netdev(master);
 367 err1:
 368        dev_put(slave);
 369        return err;
 370}
 371
 372static int dlci_del(struct dlci_add *dlci)
 373{
 374        struct dlci_local       *dlp;
 375        struct frad_local       *flp;
 376        struct net_device       *master, *slave;
 377        int                     err;
 378        bool                    found = false;
 379
 380        rtnl_lock();
 381
 382        /* validate slave device */
 383        master = __dev_get_by_name(&init_net, dlci->devname);
 384        if (!master) {
 385                err = -ENODEV;
 386                goto out;
 387        }
 388
 389        list_for_each_entry(dlp, &dlci_devs, list) {
 390                if (dlp->master == master) {
 391                        found = true;
 392                        break;
 393                }
 394        }
 395        if (!found) {
 396                err = -ENODEV;
 397                goto out;
 398        }
 399
 400        if (netif_running(master)) {
 401                err = -EBUSY;
 402                goto out;
 403        }
 404
 405        dlp = netdev_priv(master);
 406        slave = dlp->slave;
 407        flp = netdev_priv(slave);
 408
 409        err = (*flp->deassoc)(slave, master);
 410        if (!err) {
 411                list_del(&dlp->list);
 412
 413                unregister_netdevice(master);
 414
 415                dev_put(slave);
 416        }
 417out:
 418        rtnl_unlock();
 419        return err;
 420}
 421
 422static int dlci_ioctl(unsigned int cmd, void __user *arg)
 423{
 424        struct dlci_add add;
 425        int err;
 426        
 427        if (!capable(CAP_NET_ADMIN))
 428                return -EPERM;
 429
 430        if (copy_from_user(&add, arg, sizeof(struct dlci_add)))
 431                return -EFAULT;
 432
 433        switch (cmd)
 434        {
 435                case SIOCADDDLCI:
 436                        err = dlci_add(&add);
 437
 438                        if (!err)
 439                                if (copy_to_user(arg, &add, sizeof(struct dlci_add)))
 440                                        return -EFAULT;
 441                        break;
 442
 443                case SIOCDELDLCI:
 444                        err = dlci_del(&add);
 445                        break;
 446
 447                default:
 448                        err = -EINVAL;
 449        }
 450
 451        return err;
 452}
 453
 454static const struct header_ops dlci_header_ops = {
 455        .create = dlci_header,
 456};
 457
 458static const struct net_device_ops dlci_netdev_ops = {
 459        .ndo_open       = dlci_open,
 460        .ndo_stop       = dlci_close,
 461        .ndo_do_ioctl   = dlci_dev_ioctl,
 462        .ndo_start_xmit = dlci_transmit,
 463        .ndo_change_mtu = dlci_change_mtu,
 464};
 465
 466static void dlci_setup(struct net_device *dev)
 467{
 468        struct dlci_local *dlp = netdev_priv(dev);
 469
 470        dev->flags              = 0;
 471        dev->header_ops         = &dlci_header_ops;
 472        dev->netdev_ops         = &dlci_netdev_ops;
 473        dev->needs_free_netdev  = true;
 474
 475        dlp->receive            = dlci_receive;
 476
 477        dev->type               = ARPHRD_DLCI;
 478        dev->hard_header_len    = sizeof(struct frhdr);
 479        dev->addr_len           = sizeof(short);
 480
 481}
 482
 483/* if slave is unregistering, then cleanup master */
 484static int dlci_dev_event(struct notifier_block *unused,
 485                          unsigned long event, void *ptr)
 486{
 487        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 488
 489        if (dev_net(dev) != &init_net)
 490                return NOTIFY_DONE;
 491
 492        if (event == NETDEV_UNREGISTER) {
 493                struct dlci_local *dlp;
 494
 495                list_for_each_entry(dlp, &dlci_devs, list) {
 496                        if (dlp->slave == dev) {
 497                                list_del(&dlp->list);
 498                                unregister_netdevice(dlp->master);
 499                                dev_put(dlp->slave);
 500                                break;
 501                        }
 502                }
 503        }
 504        return NOTIFY_DONE;
 505}
 506
 507static struct notifier_block dlci_notifier = {
 508        .notifier_call = dlci_dev_event,
 509};
 510
 511static int __init init_dlci(void)
 512{
 513        dlci_ioctl_set(dlci_ioctl);
 514        register_netdevice_notifier(&dlci_notifier);
 515
 516        printk("%s.\n", version);
 517
 518        return 0;
 519}
 520
 521static void __exit dlci_exit(void)
 522{
 523        struct dlci_local       *dlp, *nxt;
 524        
 525        dlci_ioctl_set(NULL);
 526        unregister_netdevice_notifier(&dlci_notifier);
 527
 528        rtnl_lock();
 529        list_for_each_entry_safe(dlp, nxt, &dlci_devs, list) {
 530                unregister_netdevice(dlp->master);
 531                dev_put(dlp->slave);
 532        }
 533        rtnl_unlock();
 534}
 535
 536module_init(init_dlci);
 537module_exit(dlci_exit);
 538
 539MODULE_AUTHOR("Mike McLagan");
 540MODULE_DESCRIPTION("Frame Relay DLCI layer");
 541MODULE_LICENSE("GPL");
 542