net/rose/rose_in.c

   1 /*
   2  *      ROSE release 003
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      Most of this code is based on the SDL diagrams published in the 7th
  13  *      ARRL Computer Networking Conference papers. The diagrams have mistakes
  14  *      in them, but are mostly correct. Before you modify the code could you
  15  *      read the SDL diagrams as the code is not obvious and probably very
  16  *      easy to break;
  17  *
  18  *      History
  19  *      ROSE 001        Jonathan(G4KLX) Cloned from nr_in.c
  20  *      ROSE 002        Jonathan(G4KLX) Return cause and diagnostic codes from Clear Requests.
  21  *      ROSE 003        Jonathan(G4KLX) New timer architecture.
  22  *                                      Removed M bit processing.
  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 <net/ax25.h>
  36 #include <linux/inet.h>
  37 #include <linux/netdevice.h>
  38 #include <linux/skbuff.h>
  39 #include <net/sock.h>
  40 #include <net/ip.h>                     /* For ip_rcv */
  41 #include <asm/segment.h>
  42 #include <asm/system.h>
  43 #include <linux/fcntl.h>
  44 #include <linux/mm.h>
  45 #include <linux/interrupt.h>
  46 #include <net/rose.h>
  47
  48 /*
  49  * State machine for state 1, Awaiting Call Accepted State.
  50  * The handling of the timer(s) is in file rose_timer.c.
  51  * Handling of state 0 and connection release is in af_rose.c.
  52  */
  53 static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  54 {
  55         switch (frametype) {
  56
  57                 case ROSE_CALL_ACCEPTED:
  58                         rose_stop_timer(sk);
  59                         rose_start_idletimer(sk);
  60                         sk->protinfo.rose->condition = 0x00;
  61                         sk->protinfo.rose->vs        = 0;
  62                         sk->protinfo.rose->va        = 0;
  63                         sk->protinfo.rose->vr        = 0;
  64                         sk->protinfo.rose->vl        = 0;
  65                         sk->protinfo.rose->state     = ROSE_STATE_3;
  66                         sk->state                    = TCP_ESTABLISHED;
  67                         if (!sk->dead)
  68                                 sk->state_change(sk);
  69                         break;
  70
  71                 case ROSE_CLEAR_REQUEST:
  72                         rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  73                         rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
  74                         sk->protinfo.rose->neighbour->use--;
  75                         break;
  76
  77                 default:
  78                         break;
  79         }
  80
  81         return 0;
  82 }
  83
  84 /*
  85  * State machine for state 2, Awaiting Clear Confirmation State.
  86  * The handling of the timer(s) is in file rose_timer.c
  87  * Handling of state 0 and connection release is in af_rose.c.
  88  */
  89 static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  90 {
  91         switch (frametype) {
  92
  93                 case ROSE_CLEAR_REQUEST:
  94                         rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  95                         rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
  96                         sk->protinfo.rose->neighbour->use--;
  97                         break;
  98
  99                 case ROSE_CLEAR_CONFIRMATION:
 100                         rose_disconnect(sk, 0, -1, -1);
 101                         sk->protinfo.rose->neighbour->use--;
 102                         break;
 103
 104                 default:
 105                         break;
 106         }
 107
 108         return 0;
 109 }
 110
 111 /*
 112  * State machine for state 3, Connected State.
 113  * The handling of the timer(s) is in file rose_timer.c
 114  * Handling of state 0 and connection release is in af_rose.c.
 115  */
 116 static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
 117 {
 118         int queued = 0;
 119
 120         switch (frametype) {
 121
 122                 case ROSE_RESET_REQUEST:
 123                         rose_stop_timer(sk);
 124                         rose_start_idletimer(sk);
 125                         rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
 126                         sk->protinfo.rose->condition = 0x00;
 127                         sk->protinfo.rose->vs        = 0;
 128                         sk->protinfo.rose->vr        = 0;
 129                         sk->protinfo.rose->va        = 0;
 130                         sk->protinfo.rose->vl        = 0;
 131                         rose_requeue_frames(sk);
 132                         break;
 133
 134                 case ROSE_CLEAR_REQUEST:
 135                         rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 136                         rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 137                         sk->protinfo.rose->neighbour->use--;
 138                         break;
 139
 140                 case ROSE_RR:
 141                 case ROSE_RNR:
 142                         if (!rose_validate_nr(sk, nr)) {
 143                                 rose_write_internal(sk, ROSE_RESET_REQUEST);
 144                                 sk->protinfo.rose->condition = 0x00;
 145                                 sk->protinfo.rose->vs        = 0;
 146                                 sk->protinfo.rose->vr        = 0;
 147                                 sk->protinfo.rose->va        = 0;
 148                                 sk->protinfo.rose->vl        = 0;
 149                                 sk->protinfo.rose->state     = ROSE_STATE_4;
 150                                 rose_start_t2timer(sk);
 151                                 rose_stop_idletimer(sk);
 152                         } else {
 153                                 rose_frames_acked(sk, nr);
 154                                 if (frametype == ROSE_RNR) {
 155                                         sk->protinfo.rose->condition |= ROSE_COND_PEER_RX_BUSY;
 156                                 } else {
 157                                         sk->protinfo.rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 158                                 }
 159                         }
 160                         break;
 161
 162                 case ROSE_DATA: /* XXX */
 163                         sk->protinfo.rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 164                         if (!rose_validate_nr(sk, nr)) {
 165                                 rose_write_internal(sk, ROSE_RESET_REQUEST);
 166                                 sk->protinfo.rose->condition = 0x00;
 167                                 sk->protinfo.rose->vs        = 0;
 168                                 sk->protinfo.rose->vr        = 0;
 169                                 sk->protinfo.rose->va        = 0;
 170                                 sk->protinfo.rose->vl        = 0;
 171                                 sk->protinfo.rose->state     = ROSE_STATE_4;
 172                                 rose_start_t2timer(sk);
 173                                 rose_stop_idletimer(sk);
 174                                 break;
 175                         }
 176                         rose_frames_acked(sk, nr);
 177                         if (ns == sk->protinfo.rose->vr) {
 178                                 rose_start_idletimer(sk);
 179                                 if (sock_queue_rcv_skb(sk, skb) == 0) {
 180                                         sk->protinfo.rose->vr = (sk->protinfo.rose->vr + 1) % ROSE_MODULUS;
 181                                         queued = 1;
 182                                 } else {
 183                                         /* Should never happen ! */
 184                                         rose_write_internal(sk, ROSE_RESET_REQUEST);
 185                                         sk->protinfo.rose->condition = 0x00;
 186                                         sk->protinfo.rose->vs        = 0;
 187                                         sk->protinfo.rose->vr        = 0;
 188                                         sk->protinfo.rose->va        = 0;
 189                                         sk->protinfo.rose->vl        = 0;
 190                                         sk->protinfo.rose->state     = ROSE_STATE_4;
 191                                         rose_start_t2timer(sk);
 192                                         rose_stop_idletimer(sk);
 193                                         break;
 194                                 }
 195                                 if (atomic_read(&sk->rmem_alloc) > (sk->rcvbuf / 2))
 196                                         sk->protinfo.rose->condition |= ROSE_COND_OWN_RX_BUSY;
 197                         }
 198                         /*
 199                          * If the window is full, ack the frame, else start the
 200                          * acknowledge hold back timer.
 201                          */
 202                         if (((sk->protinfo.rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == sk->protinfo.rose->vr) {
 203                                 sk->protinfo.rose->condition &= ~ROSE_COND_ACK_PENDING;
 204                                 rose_stop_timer(sk);
 205                                 rose_enquiry_response(sk);
 206                         } else {
 207                                 sk->protinfo.rose->condition |= ROSE_COND_ACK_PENDING;
 208                                 rose_start_hbtimer(sk);
 209                         }
 210                         break;
 211
 212                 default:
 213                         printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
 214                         break;
 215         }
 216
 217         return queued;
 218 }
 219
 220 /*
 221  * State machine for state 4, Awaiting Reset Confirmation State.
 222  * The handling of the timer(s) is in file rose_timer.c
 223  * Handling of state 0 and connection release is in af_rose.c.
 224  */
 225 static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 226 {
 227         switch (frametype) {
 228
 229                 case ROSE_RESET_REQUEST:
 230                         rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
 231                 case ROSE_RESET_CONFIRMATION:
 232                         rose_stop_timer(sk);
 233                         rose_start_idletimer(sk);
 234                         sk->protinfo.rose->condition = 0x00;
 235                         sk->protinfo.rose->va        = 0;
 236                         sk->protinfo.rose->vr        = 0;
 237                         sk->protinfo.rose->vs        = 0;
 238                         sk->protinfo.rose->vl        = 0;
 239                         sk->protinfo.rose->state     = ROSE_STATE_3;
 240                         rose_requeue_frames(sk);
 241                         break;
 242
 243                 case ROSE_CLEAR_REQUEST:
 244                         rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 245                         rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 246                         sk->protinfo.rose->neighbour->use--;
 247                         break;
 248
 249                 default:
 250                         break;
 251         }
 252
 253         return 0;
 254 }
 255
 256 /*
 257  * State machine for state 5, Awaiting Call Acceptance State.
 258  * The handling of the timer(s) is in file rose_timer.c
 259  * Handling of state 0 and connection release is in af_rose.c.
 260  */
 261 static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 262 {
 263         if (frametype == ROSE_CLEAR_REQUEST) {
 264                 rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 265                 rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 266                 sk->protinfo.rose->neighbour->use--;
 267         }
 268
 269         return 0;
 270 }
 271
 272 /* Higher level upcall for a LAPB frame */
 273 int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 274 {
 275         int queued = 0, frametype, ns, nr, q, d, m;
 276
 277         if (sk->protinfo.rose->state == ROSE_STATE_0)
 278                 return 0;
 279
 280         frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
 281
 282         switch (sk->protinfo.rose->state) {
 283                 case ROSE_STATE_1:
 284                         queued = rose_state1_machine(sk, skb, frametype);
 285                         break;
 286                 case ROSE_STATE_2:
 287                         queued = rose_state2_machine(sk, skb, frametype);
 288                         break;
 289                 case ROSE_STATE_3:
 290                         queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
 291                         break;
 292                 case ROSE_STATE_4:
 293                         queued = rose_state4_machine(sk, skb, frametype);
 294                         break;
 295                 case ROSE_STATE_5:
 296                         queued = rose_state5_machine(sk, skb, frametype);
 297                         break;
 298         }
 299
 300         rose_kick(sk);
 301
 302         return queued;
 303 }