LXR linux/net/x25/x25

   1/*
   2 *      X.25 Packet Layer release 002
   3 *
   4 *      This is ALPHA test software. This code may break your machine,
   5 *      randomly fail to work with new releases, misbehave and/or generally
   6 *      screw up. It might even work.
   7 *
   8 *      This code REQUIRES 2.1.15 or higher
   9 *
  10 *      This module:
  11 *              This module is free software; you can redistribute it and/or
  12 *              modify it under the terms of the GNU General Public License
  13 *              as published by the Free Software Foundation; either version
  14 *              2 of the License, or (at your option) any later version.
  15 *
  16 *      History
  17 *      X.25 001        Jonathan Naylor   Started coding.
  18 *      X.25 002        Jonathan Naylor   New timer architecture.
  19 *      mar/20/00       Daniela Squassoni Disabling/enabling of facilities
  20 *                                        negotiation.
  21 *      2000-09-04      Henner Eisen      dev_hold() / dev_put() for x25_neigh.
  22 */
  23
  24#define pr_fmt(fmt) "X25: " fmt
  25
  26#include <linux/kernel.h>
  27#include <linux/jiffies.h>
  28#include <linux/timer.h>
  29#include <linux/slab.h>
  30#include <linux/netdevice.h>
  31#include <linux/skbuff.h>
  32#include <linux/uaccess.h>
  33#include <linux/init.h>
  34#include <net/x25.h>
  35
  36LIST_HEAD(x25_neigh_list);
  37DEFINE_RWLOCK(x25_neigh_list_lock);
  38
  39static void x25_t20timer_expiry(struct timer_list *);
  40
  41static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
  42static void x25_transmit_restart_request(struct x25_neigh *nb);
  43
  44/*
  45 *      Linux set/reset timer routines
  46 */
  47static inline void x25_start_t20timer(struct x25_neigh *nb)
  48{
  49        mod_timer(&nb->t20timer, jiffies + nb->t20);
  50}
  51
  52static void x25_t20timer_expiry(struct timer_list *t)
  53{
  54        struct x25_neigh *nb = from_timer(nb, t, t20timer);
  55
  56        x25_transmit_restart_request(nb);
  57
  58        x25_start_t20timer(nb);
  59}
  60
  61static inline void x25_stop_t20timer(struct x25_neigh *nb)
  62{
  63        del_timer(&nb->t20timer);
  64}
  65
  66static inline int x25_t20timer_pending(struct x25_neigh *nb)
  67{
  68        return timer_pending(&nb->t20timer);
  69}
  70
  71/*
  72 *      This handles all restart and diagnostic frames.
  73 */
  74void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
  75                      unsigned short frametype)
  76{
  77        struct sk_buff *skbn;
  78        int confirm;
  79
  80        switch (frametype) {
  81        case X25_RESTART_REQUEST:
  82                confirm = !x25_t20timer_pending(nb);
  83                x25_stop_t20timer(nb);
  84                nb->state = X25_LINK_STATE_3;
  85                if (confirm)
  86                        x25_transmit_restart_confirmation(nb);
  87                break;
  88
  89        case X25_RESTART_CONFIRMATION:
  90                x25_stop_t20timer(nb);
  91                nb->state = X25_LINK_STATE_3;
  92                break;
  93
  94        case X25_DIAGNOSTIC:
  95                if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
  96                        break;
  97
  98                pr_warn("diagnostic #%d - %02X %02X %02X\n",
  99                       skb->data[3], skb->data[4],
 100                       skb->data[5], skb->data[6]);
 101                break;
 102
 103        default:
 104                pr_warn("received unknown %02X with LCI 000\n",
 105                       frametype);
 106                break;
 107        }
 108
 109        if (nb->state == X25_LINK_STATE_3)
 110                while ((skbn = skb_dequeue(&nb->queue)) != NULL)
 111                        x25_send_frame(skbn, nb);
 112}
 113
 114/*
 115 *      This routine is called when a Restart Request is needed
 116 */
 117static void x25_transmit_restart_request(struct x25_neigh *nb)
 118{
 119        unsigned char *dptr;
 120        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
 121        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 122
 123        if (!skb)
 124                return;
 125
 126        skb_reserve(skb, X25_MAX_L2_LEN);
 127
 128        dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
 129
 130        *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
 131        *dptr++ = 0x00;
 132        *dptr++ = X25_RESTART_REQUEST;
 133        *dptr++ = 0x00;
 134        *dptr++ = 0;
 135
 136        skb->sk = NULL;
 137
 138        x25_send_frame(skb, nb);
 139}
 140
 141/*
 142 * This routine is called when a Restart Confirmation is needed
 143 */
 144static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
 145{
 146        unsigned char *dptr;
 147        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
 148        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 149
 150        if (!skb)
 151                return;
 152
 153        skb_reserve(skb, X25_MAX_L2_LEN);
 154
 155        dptr = skb_put(skb, X25_STD_MIN_LEN);
 156
 157        *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
 158        *dptr++ = 0x00;
 159        *dptr++ = X25_RESTART_CONFIRMATION;
 160
 161        skb->sk = NULL;
 162
 163        x25_send_frame(skb, nb);
 164}
 165
 166/*
 167 *      This routine is called when a Clear Request is needed outside of the context
 168 *      of a connected socket.
 169 */
 170void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
 171                                unsigned char cause)
 172{
 173        unsigned char *dptr;
 174        int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
 175        struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 176
 177        if (!skb)
 178                return;
 179
 180        skb_reserve(skb, X25_MAX_L2_LEN);
 181
 182        dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
 183
 184        *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
 185                                         X25_GFI_EXTSEQ :
 186                                         X25_GFI_STDSEQ);
 187        *dptr++ = (lci >> 0) & 0xFF;
 188        *dptr++ = X25_CLEAR_REQUEST;
 189        *dptr++ = cause;
 190        *dptr++ = 0x00;
 191
 192        skb->sk = NULL;
 193
 194        x25_send_frame(skb, nb);
 195}
 196
 197void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
 198{
 199        switch (nb->state) {
 200        case X25_LINK_STATE_0:
 201                skb_queue_tail(&nb->queue, skb);
 202                nb->state = X25_LINK_STATE_1;
 203                x25_establish_link(nb);
 204                break;
 205        case X25_LINK_STATE_1:
 206        case X25_LINK_STATE_2:
 207                skb_queue_tail(&nb->queue, skb);
 208                break;
 209        case X25_LINK_STATE_3:
 210                x25_send_frame(skb, nb);
 211                break;
 212        }
 213}
 214
 215/*
 216 *      Called when the link layer has become established.
 217 */
 218void x25_link_established(struct x25_neigh *nb)
 219{
 220        switch (nb->state) {
 221        case X25_LINK_STATE_0:
 222                nb->state = X25_LINK_STATE_2;
 223                break;
 224        case X25_LINK_STATE_1:
 225                x25_transmit_restart_request(nb);
 226                nb->state = X25_LINK_STATE_2;
 227                x25_start_t20timer(nb);
 228                break;
 229        }
 230}
 231
 232/*
 233 *      Called when the link layer has terminated, or an establishment
 234 *      request has failed.
 235 */
 236
 237void x25_link_terminated(struct x25_neigh *nb)
 238{
 239        nb->state = X25_LINK_STATE_0;
 240        /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
 241        x25_kill_by_neigh(nb);
 242}
 243
 244/*
 245 *      Add a new device.
 246 */
 247void x25_link_device_up(struct net_device *dev)
 248{
 249        struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
 250
 251        if (!nb)
 252                return;
 253
 254        skb_queue_head_init(&nb->queue);
 255        timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);
 256
 257        dev_hold(dev);
 258        nb->dev      = dev;
 259        nb->state    = X25_LINK_STATE_0;
 260        nb->extended = 0;
 261        /*
 262         * Enables negotiation
 263         */
 264        nb->global_facil_mask = X25_MASK_REVERSE |
 265                                       X25_MASK_THROUGHPUT |
 266                                       X25_MASK_PACKET_SIZE |
 267                                       X25_MASK_WINDOW_SIZE;
 268        nb->t20      = sysctl_x25_restart_request_timeout;
 269        refcount_set(&nb->refcnt, 1);
 270
 271        write_lock_bh(&x25_neigh_list_lock);
 272        list_add(&nb->node, &x25_neigh_list);
 273        write_unlock_bh(&x25_neigh_list_lock);
 274}
 275
 276/**
 277 *      __x25_remove_neigh - remove neighbour from x25_neigh_list
 278 *      @nb - neigh to remove
 279 *
 280 *      Remove neighbour from x25_neigh_list. If it was there.
 281 *      Caller must hold x25_neigh_list_lock.
 282 */
 283static void __x25_remove_neigh(struct x25_neigh *nb)
 284{
 285        skb_queue_purge(&nb->queue);
 286        x25_stop_t20timer(nb);
 287
 288        if (nb->node.next) {
 289                list_del(&nb->node);
 290                x25_neigh_put(nb);
 291        }
 292}
 293
 294/*
 295 *      A device has been removed, remove its links.
 296 */
 297void x25_link_device_down(struct net_device *dev)
 298{
 299        struct x25_neigh *nb;
 300        struct list_head *entry, *tmp;
 301
 302        write_lock_bh(&x25_neigh_list_lock);
 303
 304        list_for_each_safe(entry, tmp, &x25_neigh_list) {
 305                nb = list_entry(entry, struct x25_neigh, node);
 306
 307                if (nb->dev == dev) {
 308                        __x25_remove_neigh(nb);
 309                        dev_put(dev);
 310                }
 311        }
 312
 313        write_unlock_bh(&x25_neigh_list_lock);
 314}
 315
 316/*
 317 *      Given a device, return the neighbour address.
 318 */
 319struct x25_neigh *x25_get_neigh(struct net_device *dev)
 320{
 321        struct x25_neigh *nb, *use = NULL;
 322        struct list_head *entry;
 323
 324        read_lock_bh(&x25_neigh_list_lock);
 325        list_for_each(entry, &x25_neigh_list) {
 326                nb = list_entry(entry, struct x25_neigh, node);
 327
 328                if (nb->dev == dev) {
 329                        use = nb;
 330                        break;
 331                }
 332        }
 333
 334        if (use)
 335                x25_neigh_hold(use);
 336        read_unlock_bh(&x25_neigh_list_lock);
 337        return use;
 338}
 339
 340/*
 341 *      Handle the ioctls that control the subscription functions.
 342 */
 343int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
 344{
 345        struct x25_subscrip_struct x25_subscr;
 346        struct x25_neigh *nb;
 347        struct net_device *dev;
 348        int rc = -EINVAL;
 349
 350        if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
 351                goto out;
 352
 353        rc = -EFAULT;
 354        if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
 355                goto out;
 356
 357        rc = -EINVAL;
 358        if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
 359                goto out;
 360
 361        if ((nb = x25_get_neigh(dev)) == NULL)
 362                goto out_dev_put;
 363
 364        dev_put(dev);
 365
 366        if (cmd == SIOCX25GSUBSCRIP) {
 367                read_lock_bh(&x25_neigh_list_lock);
 368                x25_subscr.extended          = nb->extended;
 369                x25_subscr.global_facil_mask = nb->global_facil_mask;
 370                read_unlock_bh(&x25_neigh_list_lock);
 371                rc = copy_to_user(arg, &x25_subscr,
 372                                  sizeof(x25_subscr)) ? -EFAULT : 0;
 373        } else {
 374                rc = -EINVAL;
 375                if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
 376                        rc = 0;
 377                        write_lock_bh(&x25_neigh_list_lock);
 378                        nb->extended         = x25_subscr.extended;
 379                        nb->global_facil_mask = x25_subscr.global_facil_mask;
 380                        write_unlock_bh(&x25_neigh_list_lock);
 381                }
 382        }
 383        x25_neigh_put(nb);
 384out:
 385        return rc;
 386out_dev_put:
 387        dev_put(dev);
 388        goto out;
 389}
 390
 391
 392/*
 393 *      Release all memory associated with X.25 neighbour structures.
 394 */
 395void __exit x25_link_free(void)
 396{
 397        struct x25_neigh *nb;
 398        struct list_head *entry, *tmp;
 399
 400        write_lock_bh(&x25_neigh_list_lock);
 401
 402        list_for_each_safe(entry, tmp, &x25_neigh_list) {
 403                struct net_device *dev;
 404
 405                nb = list_entry(entry, struct x25_neigh, node);
 406                dev = nb->dev;
 407                __x25_remove_neigh(nb);
 408                dev_put(dev);
 409        }
 410        write_unlock_bh(&x25_neigh_list_lock);
 411}
 412