LXR linux/net/rose/rose

   1/*
   2 * This program is free software; you can redistribute it and/or modify
   3 * it under the terms of the GNU General Public License as published by
   4 * the Free Software Foundation; either version 2 of the License, or
   5 * (at your option) any later version.
   6 *
   7 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8 *
   9 * Most of this code is based on the SDL diagrams published in the 7th ARRL
  10 * Computer Networking Conference papers. The diagrams have mistakes in them,
  11 * but are mostly correct. Before you modify the code could you read the SDL
  12 * diagrams as the code is not obvious and probably very easy to break.
  13 */
  14#include <linux/errno.h>
  15#include <linux/types.h>
  16#include <linux/socket.h>
  17#include <linux/in.h>
  18#include <linux/kernel.h>
  19#include <linux/timer.h>
  20#include <linux/string.h>
  21#include <linux/sockios.h>
  22#include <linux/net.h>
  23#include <net/ax25.h>
  24#include <linux/inet.h>
  25#include <linux/netdevice.h>
  26#include <linux/skbuff.h>
  27#include <net/sock.h>
  28#include <net/tcp_states.h>
  29#include <linux/fcntl.h>
  30#include <linux/mm.h>
  31#include <linux/interrupt.h>
  32#include <net/rose.h>
  33
  34/*
  35 * State machine for state 1, Awaiting Call Accepted State.
  36 * The handling of the timer(s) is in file rose_timer.c.
  37 * Handling of state 0 and connection release is in af_rose.c.
  38 */
  39static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  40{
  41        struct rose_sock *rose = rose_sk(sk);
  42
  43        switch (frametype) {
  44        case ROSE_CALL_ACCEPTED:
  45                rose_stop_timer(sk);
  46                rose_start_idletimer(sk);
  47                rose->condition = 0x00;
  48                rose->vs        = 0;
  49                rose->va        = 0;
  50                rose->vr        = 0;
  51                rose->vl        = 0;
  52                rose->state     = ROSE_STATE_3;
  53                sk->sk_state    = TCP_ESTABLISHED;
  54                if (!sock_flag(sk, SOCK_DEAD))
  55                        sk->sk_state_change(sk);
  56                break;
  57
  58        case ROSE_CLEAR_REQUEST:
  59                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  60                rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
  61                rose->neighbour->use--;
  62                break;
  63
  64        default:
  65                break;
  66        }
  67
  68        return 0;
  69}
  70
  71/*
  72 * State machine for state 2, Awaiting Clear Confirmation State.
  73 * The handling of the timer(s) is in file rose_timer.c
  74 * Handling of state 0 and connection release is in af_rose.c.
  75 */
  76static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  77{
  78        struct rose_sock *rose = rose_sk(sk);
  79
  80        switch (frametype) {
  81        case ROSE_CLEAR_REQUEST:
  82                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  83                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
  84                rose->neighbour->use--;
  85                break;
  86
  87        case ROSE_CLEAR_CONFIRMATION:
  88                rose_disconnect(sk, 0, -1, -1);
  89                rose->neighbour->use--;
  90                break;
  91
  92        default:
  93                break;
  94        }
  95
  96        return 0;
  97}
  98
  99/*
 100 * State machine for state 3, Connected State.
 101 * The handling of the timer(s) is in file rose_timer.c
 102 * Handling of state 0 and connection release is in af_rose.c.
 103 */
 104static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
 105{
 106        struct rose_sock *rose = rose_sk(sk);
 107        int queued = 0;
 108
 109        switch (frametype) {
 110        case ROSE_RESET_REQUEST:
 111                rose_stop_timer(sk);
 112                rose_start_idletimer(sk);
 113                rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
 114                rose->condition = 0x00;
 115                rose->vs        = 0;
 116                rose->vr        = 0;
 117                rose->va        = 0;
 118                rose->vl        = 0;
 119                rose_requeue_frames(sk);
 120                break;
 121
 122        case ROSE_CLEAR_REQUEST:
 123                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 124                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 125                rose->neighbour->use--;
 126                break;
 127
 128        case ROSE_RR:
 129        case ROSE_RNR:
 130                if (!rose_validate_nr(sk, nr)) {
 131                        rose_write_internal(sk, ROSE_RESET_REQUEST);
 132                        rose->condition = 0x00;
 133                        rose->vs        = 0;
 134                        rose->vr        = 0;
 135                        rose->va        = 0;
 136                        rose->vl        = 0;
 137                        rose->state     = ROSE_STATE_4;
 138                        rose_start_t2timer(sk);
 139                        rose_stop_idletimer(sk);
 140                } else {
 141                        rose_frames_acked(sk, nr);
 142                        if (frametype == ROSE_RNR) {
 143                                rose->condition |= ROSE_COND_PEER_RX_BUSY;
 144                        } else {
 145                                rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 146                        }
 147                }
 148                break;
 149
 150        case ROSE_DATA: /* XXX */
 151                rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 152                if (!rose_validate_nr(sk, nr)) {
 153                        rose_write_internal(sk, ROSE_RESET_REQUEST);
 154                        rose->condition = 0x00;
 155                        rose->vs        = 0;
 156                        rose->vr        = 0;
 157                        rose->va        = 0;
 158                        rose->vl        = 0;
 159                        rose->state     = ROSE_STATE_4;
 160                        rose_start_t2timer(sk);
 161                        rose_stop_idletimer(sk);
 162                        break;
 163                }
 164                rose_frames_acked(sk, nr);
 165                if (ns == rose->vr) {
 166                        rose_start_idletimer(sk);
 167                        if (sk_filter_trim_cap(sk, skb, ROSE_MIN_LEN) == 0 &&
 168                            __sock_queue_rcv_skb(sk, skb) == 0) {
 169                                rose->vr = (rose->vr + 1) % ROSE_MODULUS;
 170                                queued = 1;
 171                        } else {
 172                                /* Should never happen ! */
 173                                rose_write_internal(sk, ROSE_RESET_REQUEST);
 174                                rose->condition = 0x00;
 175                                rose->vs        = 0;
 176                                rose->vr        = 0;
 177                                rose->va        = 0;
 178                                rose->vl        = 0;
 179                                rose->state     = ROSE_STATE_4;
 180                                rose_start_t2timer(sk);
 181                                rose_stop_idletimer(sk);
 182                                break;
 183                        }
 184                        if (atomic_read(&sk->sk_rmem_alloc) >
 185                            (sk->sk_rcvbuf >> 1))
 186                                rose->condition |= ROSE_COND_OWN_RX_BUSY;
 187                }
 188                /*
 189                 * If the window is full, ack the frame, else start the
 190                 * acknowledge hold back timer.
 191                 */
 192                if (((rose->vl + sysctl_rose_window_size) % ROSE_MODULUS) == rose->vr) {
 193                        rose->condition &= ~ROSE_COND_ACK_PENDING;
 194                        rose_stop_timer(sk);
 195                        rose_enquiry_response(sk);
 196                } else {
 197                        rose->condition |= ROSE_COND_ACK_PENDING;
 198                        rose_start_hbtimer(sk);
 199                }
 200                break;
 201
 202        default:
 203                printk(KERN_WARNING "ROSE: unknown %02X in state 3\n", frametype);
 204                break;
 205        }
 206
 207        return queued;
 208}
 209
 210/*
 211 * State machine for state 4, Awaiting Reset Confirmation State.
 212 * The handling of the timer(s) is in file rose_timer.c
 213 * Handling of state 0 and connection release is in af_rose.c.
 214 */
 215static int rose_state4_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 216{
 217        struct rose_sock *rose = rose_sk(sk);
 218
 219        switch (frametype) {
 220        case ROSE_RESET_REQUEST:
 221                rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
 222        case ROSE_RESET_CONFIRMATION:
 223                rose_stop_timer(sk);
 224                rose_start_idletimer(sk);
 225                rose->condition = 0x00;
 226                rose->va        = 0;
 227                rose->vr        = 0;
 228                rose->vs        = 0;
 229                rose->vl        = 0;
 230                rose->state     = ROSE_STATE_3;
 231                rose_requeue_frames(sk);
 232                break;
 233
 234        case ROSE_CLEAR_REQUEST:
 235                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 236                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 237                rose->neighbour->use--;
 238                break;
 239
 240        default:
 241                break;
 242        }
 243
 244        return 0;
 245}
 246
 247/*
 248 * State machine for state 5, Awaiting Call Acceptance State.
 249 * The handling of the timer(s) is in file rose_timer.c
 250 * Handling of state 0 and connection release is in af_rose.c.
 251 */
 252static int rose_state5_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 253{
 254        if (frametype == ROSE_CLEAR_REQUEST) {
 255                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 256                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 257                rose_sk(sk)->neighbour->use--;
 258        }
 259
 260        return 0;
 261}
 262
 263/* Higher level upcall for a LAPB frame */
 264int rose_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 265{
 266        struct rose_sock *rose = rose_sk(sk);
 267        int queued = 0, frametype, ns, nr, q, d, m;
 268
 269        if (rose->state == ROSE_STATE_0)
 270                return 0;
 271
 272        frametype = rose_decode(skb, &ns, &nr, &q, &d, &m);
 273
 274        switch (rose->state) {
 275        case ROSE_STATE_1:
 276                queued = rose_state1_machine(sk, skb, frametype);
 277                break;
 278        case ROSE_STATE_2:
 279                queued = rose_state2_machine(sk, skb, frametype);
 280                break;
 281        case ROSE_STATE_3:
 282                queued = rose_state3_machine(sk, skb, frametype, ns, nr, q, d, m);
 283                break;
 284        case ROSE_STATE_4:
 285                queued = rose_state4_machine(sk, skb, frametype);
 286                break;
 287        case ROSE_STATE_5:
 288                queued = rose_state5_machine(sk, skb, frametype);
 289                break;
 290        }
 291
 292        rose_kick(sk);
 293
 294        return queued;
 295}
 296