net/x25/x25_link.c

   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 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/in.h>
  28 #include <linux/kernel.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/timer.h>
  31 #include <linux/string.h>
  32 #include <linux/sockios.h>
  33 #include <linux/net.h>
  34 #include <linux/inet.h>
  35 #include <linux/netdevice.h>
  36 #include <linux/skbuff.h>
  37 #include <net/sock.h>
  38 #include <asm/system.h>
  39 #include <asm/uaccess.h>
  40 #include <linux/fcntl.h>
  41 #include <linux/mm.h>
  42 #include <linux/interrupt.h>
  43 #include <linux/init.h>
  44 #include <net/x25.h>
  45
  46 static struct list_head x25_neigh_list = LIST_HEAD_INIT(x25_neigh_list);
  47 static rwlock_t x25_neigh_list_lock = RW_LOCK_UNLOCKED;
  48
  49 static void x25_t20timer_expiry(unsigned long);
  50
  51 /*
  52  *      Linux set/reset timer routines
  53  */
  54 static inline void x25_start_t20timer(struct x25_neigh *nb)
  55 {
  56         mod_timer(&nb->t20timer, jiffies + nb->t20);
  57 }
  58
  59 static void x25_t20timer_expiry(unsigned long param)
  60 {
  61         struct x25_neigh *nb = (struct x25_neigh *)param;
  62
  63         x25_transmit_restart_request(nb);
  64
  65         x25_start_t20timer(nb);
  66 }
  67
  68 static inline void x25_stop_t20timer(struct x25_neigh *nb)
  69 {
  70         del_timer(&nb->t20timer);
  71 }
  72
  73 static inline int x25_t20timer_pending(struct x25_neigh *nb)
  74 {
  75         return timer_pending(&nb->t20timer);
  76 }
  77
  78 /*
  79  *      This handles all restart and diagnostic frames.
  80  */
  81 void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
  82                       unsigned short frametype)
  83 {
  84         struct sk_buff *skbn;
  85         int confirm;
  86
  87         switch (frametype) {
  88                 case X25_RESTART_REQUEST:
  89                         confirm = !x25_t20timer_pending(nb);
  90                         x25_stop_t20timer(nb);
  91                         nb->state = X25_LINK_STATE_3;
  92                         if (confirm)
  93                                 x25_transmit_restart_confirmation(nb);
  94                         break;
  95
  96                 case X25_RESTART_CONFIRMATION:
  97                         x25_stop_t20timer(nb);
  98                         nb->state = X25_LINK_STATE_3;
  99                         break;
 100
 101                 case X25_DIAGNOSTIC:
 102                         printk(KERN_WARNING "x25: diagnostic #%d - "
 103                                "%02X %02X %02X\n",
 104                                skb->data[3], skb->data[4],
 105                                skb->data[5], skb->data[6]);
 106                         break;
 107
 108                 default:
 109                         printk(KERN_WARNING "x25: received unknown %02X "
 110                                "with LCI 000\n", frametype);
 111                         break;
 112         }
 113
 114         if (nb->state == X25_LINK_STATE_3)
 115                 while ((skbn = skb_dequeue(&nb->queue)) != NULL)
 116                         x25_send_frame(skbn, nb);
 117 }
 118
 119 /*
 120  *      This routine is called when a Restart Request is needed
 121  */
 122 void x25_transmit_restart_request(struct x25_neigh *nb)
 123 {
 124         unsigned char *dptr;
 125         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
 126         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 127
 128         if (!skb)
 129                 return;
 130
 131         skb_reserve(skb, X25_MAX_L2_LEN);
 132
 133         dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
 134
 135         *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
 136         *dptr++ = 0x00;
 137         *dptr++ = X25_RESTART_REQUEST;
 138         *dptr++ = 0x00;
 139         *dptr++ = 0;
 140
 141         skb->sk = NULL;
 142
 143         x25_send_frame(skb, nb);
 144 }
 145
 146 /*
 147  * This routine is called when a Restart Confirmation is needed
 148  */
 149 void x25_transmit_restart_confirmation(struct x25_neigh *nb)
 150 {
 151         unsigned char *dptr;
 152         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
 153         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 154
 155         if (!skb)
 156                 return;
 157
 158         skb_reserve(skb, X25_MAX_L2_LEN);
 159
 160         dptr = skb_put(skb, X25_STD_MIN_LEN);
 161
 162         *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
 163         *dptr++ = 0x00;
 164         *dptr++ = X25_RESTART_CONFIRMATION;
 165
 166         skb->sk = NULL;
 167
 168         x25_send_frame(skb, nb);
 169 }
 170
 171 /*
 172  * This routine is called when a Diagnostic is required.
 173  */
 174 void x25_transmit_diagnostic(struct x25_neigh *nb, unsigned char diag)
 175 {
 176         unsigned char *dptr;
 177         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 1;
 178         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 179
 180         if (!skb)
 181                 return;
 182
 183         skb_reserve(skb, X25_MAX_L2_LEN);
 184
 185         dptr = skb_put(skb, X25_STD_MIN_LEN + 1);
 186
 187         *dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
 188         *dptr++ = 0x00;
 189         *dptr++ = X25_DIAGNOSTIC;
 190         *dptr++ = diag;
 191
 192         skb->sk = NULL;
 193
 194         x25_send_frame(skb, nb);
 195 }
 196
 197 /*
 198  *      This routine is called when a Clear Request is needed outside of the context
 199  *      of a connected socket.
 200  */
 201 void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
 202                                 unsigned char cause)
 203 {
 204         unsigned char *dptr;
 205         int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
 206         struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
 207
 208         if (!skb)
 209                 return;
 210
 211         skb_reserve(skb, X25_MAX_L2_LEN);
 212
 213         dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
 214
 215         *dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
 216                                          X25_GFI_EXTSEQ :
 217                                          X25_GFI_STDSEQ);
 218         *dptr++ = (lci >> 0) & 0xFF;
 219         *dptr++ = X25_CLEAR_REQUEST;
 220         *dptr++ = cause;
 221         *dptr++ = 0x00;
 222
 223         skb->sk = NULL;
 224
 225         x25_send_frame(skb, nb);
 226 }
 227
 228 void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
 229 {
 230         switch (nb->state) {
 231                 case X25_LINK_STATE_0:
 232                         skb_queue_tail(&nb->queue, skb);
 233                         nb->state = X25_LINK_STATE_1;
 234                         x25_establish_link(nb);
 235                         break;
 236                 case X25_LINK_STATE_1:
 237                 case X25_LINK_STATE_2:
 238                         skb_queue_tail(&nb->queue, skb);
 239                         break;
 240                 case X25_LINK_STATE_3:
 241                         x25_send_frame(skb, nb);
 242                         break;
 243         }
 244 }
 245
 246 /*
 247  *      Called when the link layer has become established.
 248  */
 249 void x25_link_established(struct x25_neigh *nb)
 250 {
 251         switch (nb->state) {
 252                 case X25_LINK_STATE_0:
 253                         nb->state = X25_LINK_STATE_2;
 254                         break;
 255                 case X25_LINK_STATE_1:
 256                         x25_transmit_restart_request(nb);
 257                         nb->state = X25_LINK_STATE_2;
 258                         x25_start_t20timer(nb);
 259                         break;
 260         }
 261 }
 262
 263 /*
 264  *      Called when the link layer has terminated, or an establishment
 265  *      request has failed.
 266  */
 267
 268 void x25_link_terminated(struct x25_neigh *nb)
 269 {
 270         nb->state = X25_LINK_STATE_0;
 271         /* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
 272         x25_kill_by_neigh(nb);
 273 }
 274
 275 /*
 276  *      Add a new device.
 277  */
 278 void x25_link_device_up(struct net_device *dev)
 279 {
 280         struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
 281
 282         if (!nb)
 283                 return;
 284
 285         skb_queue_head_init(&nb->queue);
 286
 287         init_timer(&nb->t20timer);
 288         nb->t20timer.data     = (unsigned long)nb;
 289         nb->t20timer.function = &x25_t20timer_expiry;
 290
 291         dev_hold(dev);
 292         nb->dev      = dev;
 293         nb->state    = X25_LINK_STATE_0;
 294         nb->extended = 0;
 295         /*
 296          * Enables negotiation
 297          */
 298         nb->global_facil_mask = X25_MASK_REVERSE |
 299                                        X25_MASK_THROUGHPUT |
 300                                        X25_MASK_PACKET_SIZE |
 301                                        X25_MASK_WINDOW_SIZE;
 302         nb->t20      = sysctl_x25_restart_request_timeout;
 303         atomic_set(&nb->refcnt, 1);
 304
 305         write_lock_bh(&x25_neigh_list_lock);
 306         list_add(&nb->node, &x25_neigh_list);
 307         write_unlock_bh(&x25_neigh_list_lock);
 308 }
 309
 310 /**
 311  *      __x25_remove_neigh - remove neighbour from x25_neigh_list
 312  *      @nb - neigh to remove
 313  *
 314  *      Remove neighbour from x25_neigh_list. If it was there.
 315  *      Caller must hold x25_neigh_list_lock.
 316  */
 317 static void __x25_remove_neigh(struct x25_neigh *nb)
 318 {
 319         skb_queue_purge(&nb->queue);
 320         x25_stop_t20timer(nb);
 321
 322         if (nb->node.next) {
 323                 list_del(&nb->node);
 324                 x25_neigh_put(nb);
 325         }
 326 }
 327
 328 /*
 329  *      A device has been removed, remove its links.
 330  */
 331 void x25_link_device_down(struct net_device *dev)
 332 {
 333         struct x25_neigh *nb;
 334         struct list_head *entry, *tmp;
 335
 336         write_lock_bh(&x25_neigh_list_lock);
 337
 338         list_for_each_safe(entry, tmp, &x25_neigh_list) {
 339                 nb = list_entry(entry, struct x25_neigh, node);
 340
 341                 if (nb->dev == dev) {
 342                         __x25_remove_neigh(nb);
 343                         dev_put(dev);
 344                 }
 345         }
 346
 347         write_unlock_bh(&x25_neigh_list_lock);
 348 }
 349
 350 /*
 351  *      Given a device, return the neighbour address.
 352  */
 353 struct x25_neigh *x25_get_neigh(struct net_device *dev)
 354 {
 355         struct x25_neigh *nb, *use = NULL;
 356         struct list_head *entry;
 357
 358         read_lock_bh(&x25_neigh_list_lock);
 359         list_for_each(entry, &x25_neigh_list) {
 360                 nb = list_entry(entry, struct x25_neigh, node);
 361
 362                 if (nb->dev == dev) {
 363                         use = nb;
 364                         break;
 365                 }
 366         }
 367
 368         if (use)
 369                 x25_neigh_hold(use);
 370         read_unlock_bh(&x25_neigh_list_lock);
 371         return use;
 372 }
 373
 374 /*
 375  *      Handle the ioctls that control the subscription functions.
 376  */
 377 int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
 378 {
 379         struct x25_subscrip_struct x25_subscr;
 380         struct x25_neigh *nb;
 381         struct net_device *dev;
 382         int rc = -EINVAL;
 383
 384         if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
 385                 goto out;
 386
 387         rc = -EFAULT;
 388         if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
 389                 goto out;
 390
 391         rc = -EINVAL;
 392         if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
 393                 goto out;
 394
 395         if ((nb = x25_get_neigh(dev)) == NULL)
 396                 goto out_dev_put;
 397
 398         dev_put(dev);
 399
 400         if (cmd == SIOCX25GSUBSCRIP) {
 401                 x25_subscr.extended          = nb->extended;
 402                 x25_subscr.global_facil_mask = nb->global_facil_mask;
 403                 rc = copy_to_user(arg, &x25_subscr,
 404                                   sizeof(x25_subscr)) ? -EFAULT : 0;
 405         } else {
 406                 rc = -EINVAL;
 407                 if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
 408                         rc = 0;
 409                         nb->extended         = x25_subscr.extended;
 410                         nb->global_facil_mask = x25_subscr.global_facil_mask;
 411                 }
 412         }
 413         x25_neigh_put(nb);
 414 out:
 415         return rc;
 416 out_dev_put:
 417         dev_put(dev);
 418         goto out;
 419 }
 420
 421
 422 /*
 423  *      Release all memory associated with X.25 neighbour structures.
 424  */
 425 void __exit x25_link_free(void)
 426 {
 427         struct x25_neigh *nb;
 428         struct list_head *entry, *tmp;
 429
 430         write_lock_bh(&x25_neigh_list_lock);
 431
 432         list_for_each_safe(entry, tmp, &x25_neigh_list) {
 433                 nb = list_entry(entry, struct x25_neigh, node);
 434                 __x25_remove_neigh(nb);
 435         }
 436         write_unlock_bh(&x25_neigh_list_lock);
 437 }