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/slab.h>
  27 #include <linux/errno.h>
  28 #include <linux/kernel.h>
  29 #include <linux/string.h>
  30 #include <linux/skbuff.h>
  31 #include <net/sock.h>
  32 #include <net/tcp_states.h>
  33 #include <net/x25.h>
  34
  35 static int x25_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  36 {
  37         struct sk_buff *skbo, *skbn = skb;
  38         struct x25_sock *x25 = x25_sk(sk);
  39
  40         if (more) {
  41                 x25->fraglen += skb->len;
  42                 skb_queue_tail(&x25->fragment_queue, skb);
  43                 skb_set_owner_r(skb, sk);
  44                 return 0;
  45         }
  46
  47         if (!more && x25->fraglen > 0) {        /* End of fragment */
  48                 int len = x25->fraglen + skb->len;
  49
  50                 if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL){
  51                         kfree_skb(skb);
  52                         return 1;
  53                 }
  54
  55                 skb_queue_tail(&x25->fragment_queue, skb);
  56
  57                 skb_reset_transport_header(skbn);
  58
  59                 skbo = skb_dequeue(&x25->fragment_queue);
  60                 skb_copy_from_linear_data(skbo, skb_put(skbn, skbo->len),
  61                                           skbo->len);
  62                 kfree_skb(skbo);
  63
  64                 while ((skbo =
  65                         skb_dequeue(&x25->fragment_queue)) != NULL) {
  66                         skb_pull(skbo, (x25->neighbour->extended) ?
  67                                         X25_EXT_MIN_LEN : X25_STD_MIN_LEN);
  68                         skb_copy_from_linear_data(skbo,
  69                                                   skb_put(skbn, skbo->len),
  70                                                   skbo->len);
  71                         kfree_skb(skbo);
  72                 }
  73
  74                 x25->fraglen = 0;
  75         }
  76
  77         skb_set_owner_r(skbn, sk);
  78         skb_queue_tail(&sk->sk_receive_queue, skbn);
  79         if (!sock_flag(sk, SOCK_DEAD))
  80                 sk->sk_data_ready(sk, skbn->len);
  81
  82         return 0;
  83 }
  84
  85 /*
  86  * State machine for state 1, Awaiting Call Accepted State.
  87  * The handling of the timer(s) is in file x25_timer.c.
  88  * Handling of state 0 and connection release is in af_x25.c.
  89  */
  90 static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  91 {
  92         struct x25_address source_addr, dest_addr;
  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                         skb_pull(skb, x25_addr_ntoa(skb->data, &source_addr, &dest_addr));
 111                         skb_pull(skb,
 112                                  x25_parse_facilities(skb, &x25->facilities,
 113                                                 &x25->dte_facilities,
 114                                                 &x25->vc_facil_mask));
 115                         /*
 116                          *      Copy any Call User Data.
 117                          */
 118                         if (skb->len > 0) {
 119                                 skb_copy_from_linear_data(skb,
 120                                               x25->calluserdata.cuddata,
 121                                               skb->len);
 122                                 x25->calluserdata.cudlength = skb->len;
 123                         }
 124                         if (!sock_flag(sk, SOCK_DEAD))
 125                                 sk->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         struct x25_sock *x25 = x25_sk(sk);
 175
 176         modulus = (x25->neighbour->extended) ? X25_EMODULUS : X25_SMODULUS;
 177
 178         switch (frametype) {
 179
 180                 case X25_RESET_REQUEST:
 181                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 182                         x25_stop_timer(sk);
 183                         x25->condition = 0x00;
 184                         x25->vs        = 0;
 185                         x25->vr        = 0;
 186                         x25->va        = 0;
 187                         x25->vl        = 0;
 188                         x25_requeue_frames(sk);
 189                         break;
 190
 191                 case X25_CLEAR_REQUEST:
 192                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 193                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 194                         break;
 195
 196                 case X25_RR:
 197                 case X25_RNR:
 198                         if (!x25_validate_nr(sk, nr)) {
 199                                 x25_clear_queues(sk);
 200                                 x25_write_internal(sk, X25_RESET_REQUEST);
 201                                 x25_start_t22timer(sk);
 202                                 x25->condition = 0x00;
 203                                 x25->vs        = 0;
 204                                 x25->vr        = 0;
 205                                 x25->va        = 0;
 206                                 x25->vl        = 0;
 207                                 x25->state     = X25_STATE_4;
 208                         } else {
 209                                 x25_frames_acked(sk, nr);
 210                                 if (frametype == X25_RNR) {
 211                                         x25->condition |= X25_COND_PEER_RX_BUSY;
 212                                 } else {
 213                                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
 214                                 }
 215                         }
 216                         break;
 217
 218                 case X25_DATA:  /* XXX */
 219                         x25->condition &= ~X25_COND_PEER_RX_BUSY;
 220                         if ((ns != x25->vr) || !x25_validate_nr(sk, nr)) {
 221                                 x25_clear_queues(sk);
 222                                 x25_write_internal(sk, X25_RESET_REQUEST);
 223                                 x25_start_t22timer(sk);
 224                                 x25->condition = 0x00;
 225                                 x25->vs        = 0;
 226                                 x25->vr        = 0;
 227                                 x25->va        = 0;
 228                                 x25->vl        = 0;
 229                                 x25->state     = X25_STATE_4;
 230                                 break;
 231                         }
 232                         x25_frames_acked(sk, nr);
 233                         if (ns == x25->vr) {
 234                                 if (x25_queue_rx_frame(sk, skb, m) == 0) {
 235                                         x25->vr = (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                                         x25->condition = 0x00;
 243                                         x25->vs        = 0;
 244                                         x25->vr        = 0;
 245                                         x25->va        = 0;
 246                                         x25->vl        = 0;
 247                                         x25->state     = X25_STATE_4;
 248                                         break;
 249                                 }
 250                                 if (atomic_read(&sk->sk_rmem_alloc) >
 251                                     (sk->sk_rcvbuf >> 1))
 252                                         x25->condition |= X25_COND_OWN_RX_BUSY;
 253                         }
 254                         /*
 255                          *      If the window is full Ack it immediately, else
 256                          *      start the holdback timer.
 257                          */
 258                         if (((x25->vl + x25->facilities.winsize_in) % modulus) == x25->vr) {
 259                                 x25->condition &= ~X25_COND_ACK_PENDING;
 260                                 x25_stop_timer(sk);
 261                                 x25_enquiry_response(sk);
 262                         } else {
 263                                 x25->condition |= X25_COND_ACK_PENDING;
 264                                 x25_start_t2timer(sk);
 265                         }
 266                         break;
 267
 268                 case X25_INTERRUPT_CONFIRMATION:
 269                         x25->intflag = 0;
 270                         break;
 271
 272                 case X25_INTERRUPT:
 273                         if (sock_flag(sk, SOCK_URGINLINE))
 274                                 queued = !sock_queue_rcv_skb(sk, skb);
 275                         else {
 276                                 skb_set_owner_r(skb, sk);
 277                                 skb_queue_tail(&x25->interrupt_in_queue, skb);
 278                                 queued = 1;
 279                         }
 280                         sk_send_sigurg(sk);
 281                         x25_write_internal(sk, X25_INTERRUPT_CONFIRMATION);
 282                         break;
 283
 284                 default:
 285                         printk(KERN_WARNING "x25: unknown %02X in state 3\n", frametype);
 286                         break;
 287         }
 288
 289         return queued;
 290 }
 291
 292 /*
 293  * State machine for state 4, Awaiting Reset Confirmation State.
 294  * The handling of the timer(s) is in file x25_timer.c
 295  * Handling of state 0 and connection release is in af_x25.c.
 296  */
 297 static int x25_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 298 {
 299         switch (frametype) {
 300
 301                 case X25_RESET_REQUEST:
 302                         x25_write_internal(sk, X25_RESET_CONFIRMATION);
 303                 case X25_RESET_CONFIRMATION: {
 304                         struct x25_sock *x25 = x25_sk(sk);
 305
 306                         x25_stop_timer(sk);
 307                         x25->condition = 0x00;
 308                         x25->va        = 0;
 309                         x25->vr        = 0;
 310                         x25->vs        = 0;
 311                         x25->vl        = 0;
 312                         x25->state     = X25_STATE_3;
 313                         x25_requeue_frames(sk);
 314                         break;
 315                 }
 316                 case X25_CLEAR_REQUEST:
 317                         x25_write_internal(sk, X25_CLEAR_CONFIRMATION);
 318                         x25_disconnect(sk, 0, skb->data[3], skb->data[4]);
 319                         break;
 320
 321                 default:
 322                         break;
 323         }
 324
 325         return 0;
 326 }
 327
 328 /* Higher level upcall for a LAPB frame */
 329 int x25_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 330 {
 331         struct x25_sock *x25 = x25_sk(sk);
 332         int queued = 0, frametype, ns, nr, q, d, m;
 333
 334         if (x25->state == X25_STATE_0)
 335                 return 0;
 336
 337         frametype = x25_decode(sk, skb, &ns, &nr, &q, &d, &m);
 338
 339         switch (x25->state) {
 340                 case X25_STATE_1:
 341                         queued = x25_state1_machine(sk, skb, frametype);
 342                         break;
 343                 case X25_STATE_2:
 344                         queued = x25_state2_machine(sk, skb, frametype);
 345                         break;
 346                 case X25_STATE_3:
 347                         queued = x25_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
 348                         break;
 349                 case X25_STATE_4:
 350                         queued = x25_state4_machine(sk, skb, frametype);
 351                         break;
 352         }
 353
 354         x25_kick(sk);
 355
 356         return queued;
 357 }
 358
 359 int x25_backlog_rcv(struct sock *sk, struct sk_buff *skb)
 360 {
 361         int queued = x25_process_rx_frame(sk, skb);
 362
 363         if (!queued)
 364                 kfree_skb(skb);
 365
 366         return 0;
 367 }