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        int                     err;
 299
 300        netif_stop_queue(dev);
 301
 302        dlp = netdev_priv(dev);
 303
 304        flp = netdev_priv(dlp->slave);
 305        err = (*flp->deactivate)(dlp->slave, dev);
 306
 307        return 0;
 308}
 309
 310static int dlci_add(struct dlci_add *dlci)
 311{
 312        struct net_device       *master, *slave;
 313        struct dlci_local       *dlp;
 314        struct frad_local       *flp;
 315        int                     err = -EINVAL;
 316
 317
 318        /* validate slave device */
 319        slave = dev_get_by_name(&init_net, dlci->devname);
 320        if (!slave)
 321                return -ENODEV;
 322
 323        if (slave->type != ARPHRD_FRAD || netdev_priv(slave) == NULL)
 324                goto err1;
 325
 326        /* create device name */
 327        master = alloc_netdev(sizeof(struct dlci_local), "dlci%d",
 328                              NET_NAME_UNKNOWN, dlci_setup);
 329        if (!master) {
 330                err = -ENOMEM;
 331                goto err1;
 332        }
 333
 334        /* make sure same slave not already registered */
 335        rtnl_lock();
 336        list_for_each_entry(dlp, &dlci_devs, list) {
 337                if (dlp->slave == slave) {
 338                        err = -EBUSY;
 339                        goto err2;
 340                }
 341        }
 342
 343        *(short *)(master->dev_addr) = dlci->dlci;
 344
 345        dlp = netdev_priv(master);
 346        dlp->slave = slave;
 347        dlp->master = master;
 348
 349        flp = netdev_priv(slave);
 350        err = (*flp->assoc)(slave, master);
 351        if (err < 0)
 352                goto err2;
 353
 354        err = register_netdevice(master);
 355        if (err < 0) 
 356                goto err2;
 357
 358        strcpy(dlci->devname, master->name);
 359
 360        list_add(&dlp->list, &dlci_devs);
 361        rtnl_unlock();
 362
 363        return 0;
 364
 365 err2:
 366        rtnl_unlock();
 367        free_netdev(master);
 368 err1:
 369        dev_put(slave);
 370        return err;
 371}
 372
 373static int dlci_del(struct dlci_add *dlci)
 374{
 375        struct dlci_local       *dlp;
 376        struct frad_local       *flp;
 377        struct net_device       *master, *slave;
 378        int                     err;
 379        bool                    found = false;
 380
 381        rtnl_lock();
 382
 383        /* validate slave device */
 384        master = __dev_get_by_name(&init_net, dlci->devname);
 385        if (!master) {
 386                err = -ENODEV;
 387                goto out;
 388        }
 389
 390        list_for_each_entry(dlp, &dlci_devs, list) {
 391                if (dlp->master == master) {
 392                        found = true;
 393                        break;
 394                }
 395        }
 396        if (!found) {
 397                err = -ENODEV;
 398                goto out;
 399        }
 400
 401        if (netif_running(master)) {
 402                err = -EBUSY;
 403                goto out;
 404        }
 405
 406        dlp = netdev_priv(master);
 407        slave = dlp->slave;
 408        flp = netdev_priv(slave);
 409
 410        err = (*flp->deassoc)(slave, master);
 411        if (!err) {
 412                list_del(&dlp->list);
 413
 414                unregister_netdevice(master);
 415
 416                dev_put(slave);
 417        }
 418out:
 419        rtnl_unlock();
 420        return err;
 421}
 422
 423static int dlci_ioctl(unsigned int cmd, void __user *arg)
 424{
 425        struct dlci_add add;
 426        int err;
 427        
 428        if (!capable(CAP_NET_ADMIN))
 429                return -EPERM;
 430
 431        if (copy_from_user(&add, arg, sizeof(struct dlci_add)))
 432                return -EFAULT;
 433
 434        switch (cmd)
 435        {
 436                case SIOCADDDLCI:
 437                        err = dlci_add(&add);
 438
 439                        if (!err)
 440                                if (copy_to_user(arg, &add, sizeof(struct dlci_add)))
 441                                        return -EFAULT;
 442                        break;
 443
 444                case SIOCDELDLCI:
 445                        err = dlci_del(&add);
 446                        break;
 447
 448                default:
 449                        err = -EINVAL;
 450        }
 451
 452        return err;
 453}
 454
 455static const struct header_ops dlci_header_ops = {
 456        .create = dlci_header,
 457};
 458
 459static const struct net_device_ops dlci_netdev_ops = {
 460        .ndo_open       = dlci_open,
 461        .ndo_stop       = dlci_close,
 462        .ndo_do_ioctl   = dlci_dev_ioctl,
 463        .ndo_start_xmit = dlci_transmit,
 464        .ndo_change_mtu = dlci_change_mtu,
 465};
 466
 467static void dlci_setup(struct net_device *dev)
 468{
 469        struct dlci_local *dlp = netdev_priv(dev);
 470
 471        dev->flags              = 0;
 472        dev->header_ops         = &dlci_header_ops;
 473        dev->netdev_ops         = &dlci_netdev_ops;
 474        dev->needs_free_netdev  = true;
 475
 476        dlp->receive            = dlci_receive;
 477
 478        dev->type               = ARPHRD_DLCI;
 479        dev->hard_header_len    = sizeof(struct frhdr);
 480        dev->addr_len           = sizeof(short);
 481
 482}
 483
 484/* if slave is unregistering, then cleanup master */
 485static int dlci_dev_event(struct notifier_block *unused,
 486                          unsigned long event, void *ptr)
 487{
 488        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 489
 490        if (dev_net(dev) != &init_net)
 491                return NOTIFY_DONE;
 492
 493        if (event == NETDEV_UNREGISTER) {
 494                struct dlci_local *dlp;
 495
 496                list_for_each_entry(dlp, &dlci_devs, list) {
 497                        if (dlp->slave == dev) {
 498                                list_del(&dlp->list);
 499                                unregister_netdevice(dlp->master);
 500                                dev_put(dlp->slave);
 501                                break;
 502                        }
 503                }
 504        }
 505        return NOTIFY_DONE;
 506}
 507
 508static struct notifier_block dlci_notifier = {
 509        .notifier_call = dlci_dev_event,
 510};
 511
 512static int __init init_dlci(void)
 513{
 514        dlci_ioctl_set(dlci_ioctl);
 515        register_netdevice_notifier(&dlci_notifier);
 516
 517        printk("%s.\n", version);
 518
 519        return 0;
 520}
 521
 522static void __exit dlci_exit(void)
 523{
 524        struct dlci_local       *dlp, *nxt;
 525        
 526        dlci_ioctl_set(NULL);
 527        unregister_netdevice_notifier(&dlci_notifier);
 528
 529        rtnl_lock();
 530        list_for_each_entry_safe(dlp, nxt, &dlci_devs, list) {
 531                unregister_netdevice(dlp->master);
 532                dev_put(dlp->slave);
 533        }
 534        rtnl_unlock();
 535}
 536
 537module_init(init_dlci);
 538module_exit(dlci_exit);
 539
 540MODULE_AUTHOR("Mike McLagan");
 541MODULE_DESCRIPTION("Frame Relay DLCI layer");
 542MODULE_LICENSE("GPL");
 543