net/x25/x25_in.c

   1 /*
   2  *      X.25 Packet Layer release 002
   3  *
   4  *      This is ALPHA test software. This code may break your machine, randomly fail to work with new
   5  *      releases, misbehave and/or generally screw up. It might even work.
   6  *
   7  *      This code REQUIRES 2.1.15 or higher
   8  *
   9  *      This module:
  10  *              This module is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  *
  15  *      History
  16  *      X.25 001        Jonathan Naylor   Started coding.
  17  *      X.25 002        Jonathan Naylor   Centralised disconnection code.
  18  *                                        New timer architecture.
  19  *      2000-03-20      Daniela Squassoni Disabling/enabling of facilities
  20  *                                        negotiation.
  21  *      2000-11-10      Henner Eisen      Check and reset for out-of-sequence
  22  *                                        i-frames.
  23  */
  24
  25 #include <linux/errno.h>
  26 #include <linux/types.h>
  27 #include <linux/socket.h>
  28 #include <linux/in.h>
  29 #include <linux/kernel.h>
  30 #include <linux/sched.h>
  31 #include <linux/timer.h>
  32 #include <linux/string.h>
  33 #include <linux/sockios.h>
  34 #include <linux/net.h>
  35 #include <linux/inet.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/skbuff.h>
  38 #include <net/sock.h>
  39 #include <net/ip.h>                     /* For ip_rcv */
  40 #include <asm/segment.h>
  41 #include <asm/system.h>
  42 #include <linux/fcntl.h>
  43 #include <linux/mm.h>
  44 #include <linux/interrupt.h>
  45 #include <net/x25.h>
  46
  47 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  48 {
  49         struct sk_buff *skbo, *skbn = skb;
  50
  51         if (more) {
  52                 sk->protinfo.x25->fraglen += skb->len;
  53                 skb_queue_tail(&sk->protinfo.x25->fragment_queue, skb);
  54                 skb_set_owner_r(skb, sk);
  55                 return 0;
  56         }
  57
  58         if (!more && sk->protinfo.x25->fraglen > 0) {   /* End of fragment */
  59                 int len = sk->protinfo.x25->fraglen + skb->len;
  60
  61                 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
  62                         kfree_skb(skb);
  63                         return 1;
  64                 }
  65
  66                 skb_queue_tail(&sk->protinfo.x25->fragment_queue, skb);
  67
  68                 skbn->h.raw = skbn->data;
  69
  70                 skbo = skb_dequeue(&sk->protinfo.x25->fragment_queue);
  71                 memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
  72                 kfree_skb(skbo);
  73
  74                 while ((skbo = skb_dequeue(&sk->protinfo.x25->fragment_queue)) != NULL) {
  75                         skb_pull(skbo, (sk->protinfo.x25->neighbour->extended) ? X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
  76                         memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
  77                         kfree_skb(skbo);
  78                 }
  79
  80                 sk->protinfo.x25->fraglen = 0;
  81         }
  82
  83         skb_set_owner_r(skbn, sk);
  84         skb_queue_tail(&sk->receive_queue, skbn);
  85         if (!sk->dead)
  86                 sk->data_ready(sk,skbn->len);
  87
  88         return 0;
  89 }
  90
  91 /*
  92  * State machine for state 1, Awaiting Call Accepted State.
  93  * The handling of the timer(s) is in file x25_timer.c.
  94  * Handling of state 0 and connection release is in af_x25.c.
  95  */
  96 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  97 {
  98         x25_address source_addr, dest_addr;
  99
 100         switch (frametype) {
 101
 102                 case X25_CALL_ACCEPTED:
 103                         x25_stop_timer(sk);
 104                         sk->protinfo.x25->condition = 0x00;
 105                         sk->protinfo.x25->vs        = 0;
 106                         sk->protinfo.x25->va        = 0;
 107                         sk->protinfo.x25->vr        = 0;
 108                         sk->protinfo.x25->vl        = 0;
 109                         sk->protinfo.x25->state     = X25_STATE_3;
 110                         sk->state                   = TCP_ESTABLISHED;
 111                         /*
 112                          *      Parse the data in the frame.
 113                          */
 114                         skb_pull(skb, X25_STD_MIN_LEN);
 115                         skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
 116                         skb_pull(skb, x25_parse_facilities(skb, &sk->protinfo.x25->facilities, &sk->protinfo.x25->vc_facil_mask));
 117                         /*
 118                          *      Copy any Call User Data.
 119                          */
 120                         if (skb->len >= 0) {
 121                                 memcpy(sk->protinfo.x25->calluserdata.cuddata, skb->data, skb->len);
 122                                 sk->protinfo.x25->calluserdata.cudlength = skb->len;
 123                         }
 124                         if (!sk->dead)
 125                                 sk->state_change(sk);
 126                         break;
 127
 128                 case X25_CLEAR_REQUEST:
 129                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 130                         x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
 131                         break;
 132
 133                 default:
 134                         break;
 135         }
 136
 137         return 0;
 138 }
 139
 140 /*
 141  * State machine for state 2, Awaiting Clear Confirmation State.
 142  * The handling of the timer(s) is in file x25_timer.c
 143  * Handling of state 0 and connection release is in af_x25.c.
 144  */
 145 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 146 {
 147         switch (frametype) {
 148
 149                 case X25_CLEAR_REQUEST:
 150                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 151                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 152                         break;
 153
 154                 case X25_CLEAR_CONFIRMATION:
 155                         x25_disconnect(sk, 0, 0, 0);
 156                         break;
 157
 158                 default:
 159                         break;
 160         }
 161
 162         return 0;
 163 }
 164
 165 /*
 166  * State machine for state 3, Connected State.
 167  * The handling of the timer(s) is in file x25_timer.c
 168  * Handling of state 0 and connection release is in af_x25.c.
 169  */
 170 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
 171 {
 172         int queued = 0;
 173         int modulus;
 174
 175         modulus = (sk->protinfo.x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
 176
 177         switch (frametype) {
 178
 179                 case X25_RESET_REQUEST:
 180                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 181                         x25_stop_timer(sk);
 182                         sk->protinfo.x25->condition = 0x00;
 183                         sk->protinfo.x25->vs        = 0;
 184                         sk->protinfo.x25->vr        = 0;
 185                         sk->protinfo.x25->va        = 0;
 186                         sk->protinfo.x25->vl        = 0;
 187                         x25_requeue_frames(sk);
 188                         break;
 189
 190                 case X25_CLEAR_REQUEST:
 191                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 192                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 193                         break;
 194
 195                 case X25_RR:
 196                 case X25_RNR:
 197                         if (!x25_validate_nr(sk, nr)) {
 198                                 x25_clear_queues(sk);
 199                                 x25_write_internal(sk, X25_RESET_REQUEST);
 200                                 x25_start_t22timer(sk);
 201                                 sk->protinfo.x25->condition = 0x00;
 202                                 sk->protinfo.x25->vs        = 0;
 203                                 sk->protinfo.x25->vr        = 0;
 204                                 sk->protinfo.x25->va        = 0;
 205                                 sk->protinfo.x25->vl        = 0;
 206                                 sk->protinfo.x25->state     = X25_STATE_4;
 207                         } else {
 208                                 x25_frames_acked(sk, nr);
 209                                 if (frametype == X25_RNR) {
 210                                         sk->protinfo.x25->condition |= X25_COND_PEER_RX_BUSY;
 211                                 } else {
 212                                         sk->protinfo.x25->condition &= ~X25_COND_PEER_RX_BUSY;
 213                                 }
 214                         }
 215                         break;
 216
 217                 case X25_DATA:  /* XXX */
 218                         sk->protinfo.x25->condition &= ~X25_COND_PEER_RX_BUSY;
 219                         if ((ns!=sk->protinfo.x25->vr) ||
 220                             !x25_validate_nr(sk, nr)) {
 221                                 x25_clear_queues(sk);
 222                                 x25_write_internal(sk, X25_RESET_REQUEST);
 223                                 x25_start_t22timer(sk);
 224                                 sk->protinfo.x25->condition = 0x00;
 225                                 sk->protinfo.x25->vs        = 0;
 226                                 sk->protinfo.x25->vr        = 0;
 227                                 sk->protinfo.x25->va        = 0;
 228                                 sk->protinfo.x25->vl        = 0;
 229                                 sk->protinfo.x25->state     = X25_STATE_4;
 230                                 break;
 231                         }
 232                         x25_frames_acked(sk, nr);
 233                         if (ns == sk->protinfo.x25->vr) {
 234                                 if (x25_queue_rx_frame(sk, skb, m) == 0) {
 235                                         sk->protinfo.x25->vr = (sk->protinfo.x25->vr + 1) % modulus;
 236                                         queued = 1;
 237                                 } else {
 238                                         /* Should never happen */
 239                                         x25_clear_queues(sk);
 240                                         x25_write_internal(sk, X25_RESET_REQUEST);
 241                                         x25_start_t22timer(sk);
 242                                         sk->protinfo.x25->condition = 0x00;
 243                                         sk->protinfo.x25->vs        = 0;
 244                                         sk->protinfo.x25->vr        = 0;
 245                                         sk->protinfo.x25->va        = 0;
 246                                         sk->protinfo.x25->vl        = 0;
 247                                         sk->protinfo.x25->state     = X25_STATE_4;
 248                                         break;
 249                                 }
 250                                 if (atomic_read(&sk->rmem_alloc) > (sk->rcvbuf / 2))
 251                                         sk->protinfo.x25->condition |= X25_COND_OWN_RX_BUSY;
 252                         }
 253                         /*
 254                          *      If the window is full Ack it immediately, else
 255                          *      start the holdback timer.
 256                          */
 257                         if (((sk->protinfo.x25->vl + sk->protinfo.x25->facilities.winsize_in) % modulus) == sk->protinfo.x25->vr) {
 258                                 sk->protinfo.x25->condition &= ~X25_COND_ACK_PENDING;
 259                                 x25_stop_timer(sk);
 260                                 x25_enquiry_response(sk);
 261                         } else {
 262                                 sk->protinfo.x25->condition |= X25_COND_ACK_PENDING;
 263                                 x25_start_t2timer(sk);
 264                         }
 265                         break;
 266
 267                 case X25_INTERRUPT_CONFIRMATION:
 268                         sk->protinfo.x25->intflag = 0;
 269                         break;
 270
 271                 case X25_INTERRUPT:
 272                         if (sk->urginline) {
 273                                 queued = (sock_queue_rcv_skb(sk, skb) == 0);
 274                         } else {
 275                                 skb_set_owner_r(skb, sk);
 276                                 skb_queue_tail(&sk->protinfo.x25->interrupt_in_queue, skb);
 277                                 queued = 1;
 278                         }
 279                         if (sk->proc != 0) {
 280                                 if (sk->proc > 0)
 281                                         kill_proc(sk->proc, SIGURG, 1);
 282                                 else
 283                                         kill_pg(-sk->proc, SIGURG, 1);
 284                                 sock_wake_async(sk->socket, 3, POLL_PRI);
 285                         }
 286                         x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
 287                         break;
 288
 289                 default:
 290                         printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
 291                         break;
 292         }
 293
 294         return queued;
 295 }
 296
 297 /*
 298  * State machine for state 4, Awaiting Reset Confirmation State.
 299  * The handling of the timer(s) is in file x25_timer.c
 300  * Handling of state 0 and connection release is in af_x25.c.
 301  */
 302 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 303 {
 304         switch (frametype) {
 305
 306                 case X25_RESET_REQUEST:
 307                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 308                 case X25_RESET_CONFIRMATION:
 309                         x25_stop_timer(sk);
 310                         sk->protinfo.x25->condition = 0x00;
 311                         sk->protinfo.x25->va        = 0;
 312                         sk->protinfo.x25->vr        = 0;
 313                         sk->protinfo.x25->vs        = 0;
 314                         sk->protinfo.x25->vl        = 0;
 315                         sk->protinfo.x25->state     = X25_STATE_3;
 316                         x25_requeue_frames(sk);
 317                         break;
 318
 319                 case X25_CLEAR_REQUEST:
 320                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 321                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 322                         break;
 323
 324                 default:
 325                         break;
 326         }
 327
 328         return 0;
 329 }
 330
 331 /* Higher level upcall for a LAPB frame */
 332 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 333 {
 334         int queued = 0, frametype, ns, nr, q, d, m;
 335
 336         if (sk->protinfo.x25->state == X25_STATE_0)
 337                 return 0;
 338
 339         frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
 340
 341         switch (sk->protinfo.x25->state) {
 342                 case X25_STATE_1:
 343                         queued = x25_state1_machine(sk, skb, frametype);
 344                         break;
 345                 case X25_STATE_2:
 346                         queued = x25_state2_machine(sk, skb, frametype);
 347                         break;
 348                 case X25_STATE_3:
 349                         queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
 350                         break;
 351                 case X25_STATE_4:
 352                         queued = x25_state4_machine(sk, skb, frametype);
 353                         break;
 354         }
 355
 356         x25_kick(sk);
 357
 358         return queued;
 359 }
 360
 361 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 362 {
 363         int queued;
 364
 365         queued = x25_process_rx_frame(sk,skb);
 366         if(!queued) kfree_skb(skb);
 367
 368         return 0;
 369 }