SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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,
   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   Centralised disconnection code.
  19  *                                        New timer architecture.
  20  *      2000-03-20      Daniela Squassoni Disabling/enabling of facilities
  21  *                                        negotiation.
  22  *      2000-11-10      Henner Eisen      Check and reset for out-of-sequence
  23  *                                        i-frames.
  24  */
  25
  26 #include <linux/errno.h>
  27 #include <linux/kernel.h>
  28 #include <linux/string.h>
  29 #include <linux/skbuff.h>
  30 #include <net/sock.h>
  31 #include <net/tcp_states.h>
  32 #include <net/x25.h>
  33
  34 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  35 {
  36         struct sk_buff *skbo, *skbn = skb;
  37         struct x25_sock *x25 = x25_sk(sk);
  38
  39         if (more) {
  40                 x25->fraglen += skb->len;
  41                 skb_queue_tail(&x25->fragment_queue, skb);
  42                 skb_set_owner_r(skb, sk);
  43                 return 0;
  44         }
  45
  46         if (!more && x25->fraglen > 0) {        /* End of fragment */
  47                 int len = x25->fraglen + skb->len;
  48
  49                 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
  50                         kfree_skb(skb);
  51                         return 1;
  52                 }
  53
  54                 skb_queue_tail(&x25->fragment_queue, skb);
  55
  56                 skb_reset_transport_header(skbn);
  57
  58                 skbo = skb_dequeue(&x25->fragment_queue);
  59                 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
  60                                           skbo->len);
  61                 kfree_skb(skbo);
  62
  63                 while ((skbo =
  64                         skb_dequeue(&x25->fragment_queue)) != NULL) {
  65                         skb_pull(skbo, (x25->neighbour->extended) ?
  66                                         X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
  67                         skb_copy_from_linear_data(skbo,
  68                                                   skb_put(skbn, skbo->len),
  69                                                   skbo->len);
  70                         kfree_skb(skbo);
  71                 }
  72
  73                 x25->fraglen = 0;
  74         }
  75
  76         skb_set_owner_r(skbn, sk);
  77         skb_queue_tail(&sk->sk_receive_queue, skbn);
  78         if (!sock_flag(sk, SOCK_DEAD))
  79                 sk->sk_data_ready(sk, skbn->len);
  80
  81         return 0;
  82 }
  83
  84 /*
  85  * State machine for state 1, Awaiting Call Accepted State.
  86  * The handling of the timer(s) is in file x25_timer.c.
  87  * Handling of state 0 and connection release is in af_x25.c.
  88  */
  89 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  90 {
  91         struct x25_address source_addr, dest_addr;
  92         int len;
  93
  94         switch (frametype) {
  95                 case X25_CALL_ACCEPTED: {
  96                         struct x25_sock *x25 = x25_sk(sk);
  97
  98                         x25_stop_timer(sk);
  99                         x25->condition = 0x00;
 100                         x25->vs        = 0;
 101                         x25->va        = 0;
 102                         x25->vr        = 0;
 103                         x25->vl        = 0;
 104                         x25->state     = X25_STATE_3;
 105                         sk->sk_state   = TCP_ESTABLISHED;
 106                         /*
 107                          *      Parse the data in the frame.
 108                          */
 109                         skb_pull(skb, X25_STD_MIN_LEN);
 110
 111                         len = x25_parse_address_block(skb, &source_addr,
 112                                                 &dest_addr);
 113                         if (len > 0)
 114                                 skb_pull(skb, len);
 115
 116                         len = x25_parse_facilities(skb, &x25->facilities,
 117                                                 &x25->dte_facilities,
 118                                                 &x25->vc_facil_mask);
 119                         if (len > 0)
 120                                 skb_pull(skb, len);
 121                         /*
 122                          *      Copy any Call User Data.
 123                          */
 124                         if (skb->len > 0) {
 125                                 skb_copy_from_linear_data(skb,
 126                                               x25->calluserdata.cuddata,
 127                                               skb->len);
 128                                 x25->calluserdata.cudlength = skb->len;
 129                         }
 130                         if (!sock_flag(sk, SOCK_DEAD))
 131                                 sk->sk_state_change(sk);
 132                         break;
 133                 }
 134                 case X25_CLEAR_REQUEST:
 135                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 136                         x25_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
 137                         break;
 138
 139                 default:
 140                         break;
 141         }
 142
 143         return 0;
 144 }
 145
 146 /*
 147  * State machine for state 2, Awaiting Clear Confirmation State.
 148  * The handling of the timer(s) is in file x25_timer.c
 149  * Handling of state 0 and connection release is in af_x25.c.
 150  */
 151 static int x25_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 152 {
 153         switch (frametype) {
 154
 155                 case X25_CLEAR_REQUEST:
 156                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 157                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 158                         break;
 159
 160                 case X25_CLEAR_CONFIRMATION:
 161                         x25_disconnect(sk, 0, 0, 0);
 162                         break;
 163
 164                 default:
 165                         break;
 166         }
 167
 168         return 0;
 169 }
 170
 171 /*
 172  * State machine for state 3, Connected State.
 173  * The handling of the timer(s) is in file x25_timer.c
 174  * Handling of state 0 and connection release is in af_x25.c.
 175  */
 176 static int x25_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
 177 {
 178         int queued = 0;
 179         int modulus;
 180         struct x25_sock *x25 = x25_sk(sk);
 181
 182         modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
 183
 184         switch (frametype) {
 185
 186                 case X25_RESET_REQUEST:
 187                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 188                         x25_stop_timer(sk);
 189                         x25->condition = 0x00;
 190                         x25->vs        = 0;
 191                         x25->vr        = 0;
 192                         x25->va        = 0;
 193                         x25->vl        = 0;
 194                         x25_requeue_frames(sk);
 195                         break;
 196
 197                 case X25_CLEAR_REQUEST:
 198                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 199                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 200                         break;
 201
 202                 case X25_RR:
 203                 case X25_RNR:
 204                         if (!x25_validate_nr(sk, nr)) {
 205                                 x25_clear_queues(sk);
 206                                 x25_write_internal(sk, X25_RESET_REQUEST);
 207                                 x25_start_t22timer(sk);
 208                                 x25->condition = 0x00;
 209                                 x25->vs        = 0;
 210                                 x25->vr        = 0;
 211                                 x25->va        = 0;
 212                                 x25->vl        = 0;
 213                                 x25->state     = X25_STATE_4;
 214                         } else {
 215                                 x25_frames_acked(sk, nr);
 216                                 if (frametype == X25_RNR) {
 217                                         x25->condition |= X25_COND_PEER_RX_BUSY;
 218                                 } else {
 219                                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
 220                                 }
 221                         }
 222                         break;
 223
 224                 case X25_DATA:  /* XXX */
 225                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
 226                         if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
 227                                 x25_clear_queues(sk);
 228                                 x25_write_internal(sk, X25_RESET_REQUEST);
 229                                 x25_start_t22timer(sk);
 230                                 x25->condition = 0x00;
 231                                 x25->vs        = 0;
 232                                 x25->vr        = 0;
 233                                 x25->va        = 0;
 234                                 x25->vl        = 0;
 235                                 x25->state     = X25_STATE_4;
 236                                 break;
 237                         }
 238                         x25_frames_acked(sk, nr);
 239                         if (ns == x25->vr) {
 240                                 if (x25_queue_rx_frame(sk, skb, m) == 0) {
 241                                         x25->vr = (x25->vr + 1) % modulus;
 242                                         queued = 1;
 243                                 } else {
 244                                         /* Should never happen */
 245                                         x25_clear_queues(sk);
 246                                         x25_write_internal(sk, X25_RESET_REQUEST);
 247                                         x25_start_t22timer(sk);
 248                                         x25->condition = 0x00;
 249                                         x25->vs        = 0;
 250                                         x25->vr        = 0;
 251                                         x25->va        = 0;
 252                                         x25->vl        = 0;
 253                                         x25->state     = X25_STATE_4;
 254                                         break;
 255                                 }
 256                                 if (atomic_read(&sk->sk_rmem_alloc) >
 257                                     (sk->sk_rcvbuf >> 1))
 258                                         x25->condition |= X25_COND_OWN_RX_BUSY;
 259                         }
 260                         /*
 261                          *      If the window is full Ack it immediately, else
 262                          *      start the holdback timer.
 263                          */
 264                         if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
 265                                 x25->condition &= ~X25_COND_ACK_PENDING;
 266                                 x25_stop_timer(sk);
 267                                 x25_enquiry_response(sk);
 268                         } else {
 269                                 x25->condition |= X25_COND_ACK_PENDING;
 270                                 x25_start_t2timer(sk);
 271                         }
 272                         break;
 273
 274                 case X25_INTERRUPT_CONFIRMATION:
 275                         x25->intflag = 0;
 276                         break;
 277
 278                 case X25_INTERRUPT:
 279                         if (sock_flag(sk, SOCK_URGINLINE))
 280                                 queued = !sock_queue_rcv_skb(sk, skb);
 281                         else {
 282                                 skb_set_owner_r(skb, sk);
 283                                 skb_queue_tail(&x25->interrupt_in_queue, skb);
 284                                 queued = 1;
 285                         }
 286                         sk_send_sigurg(sk);
 287                         x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
 288                         break;
 289
 290                 default:
 291                         printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
 292                         break;
 293         }
 294
 295         return queued;
 296 }
 297
 298 /*
 299  * State machine for state 4, Awaiting Reset Confirmation State.
 300  * The handling of the timer(s) is in file x25_timer.c
 301  * Handling of state 0 and connection release is in af_x25.c.
 302  */
 303 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 304 {
 305         switch (frametype) {
 306
 307                 case X25_RESET_REQUEST:
 308                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 309                 case X25_RESET_CONFIRMATION: {
 310                         struct x25_sock *x25 = x25_sk(sk);
 311
 312                         x25_stop_timer(sk);
 313                         x25->condition = 0x00;
 314                         x25->va        = 0;
 315                         x25->vr        = 0;
 316                         x25->vs        = 0;
 317                         x25->vl        = 0;
 318                         x25->state     = X25_STATE_3;
 319                         x25_requeue_frames(sk);
 320                         break;
 321                 }
 322                 case X25_CLEAR_REQUEST:
 323                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 324                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 325                         break;
 326
 327                 default:
 328                         break;
 329         }
 330
 331         return 0;
 332 }
 333
 334 /* Higher level upcall for a LAPB frame */
 335 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 336 {
 337         struct x25_sock *x25 = x25_sk(sk);
 338         int queued = 0, frametype, ns, nr, q, d, m;
 339
 340         if (x25->state == X25_STATE_0)
 341                 return 0;
 342
 343         frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
 344
 345         switch (x25->state) {
 346                 case X25_STATE_1:
 347                         queued = x25_state1_machine(sk, skb, frametype);
 348                         break;
 349                 case X25_STATE_2:
 350                         queued = x25_state2_machine(sk, skb, frametype);
 351                         break;
 352                 case X25_STATE_3:
 353                         queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
 354                         break;
 355                 case X25_STATE_4:
 356                         queued = x25_state4_machine(sk, skb, frametype);
 357                         break;
 358         }
 359
 360         x25_kick(sk);
 361
 362         return queued;
 363 }
 364
 365 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 366 {
 367         int queued = x25_process_rx_frame(sk, skb);
 368
 369         if (!queued)
 370                 kfree_skb(skb);
 371
 372         return 0;
 373 }