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 <asm/system.h>
  30#include <linux/fcntl.h>
  31#include <linux/mm.h>
  32#include <linux/interrupt.h>
  33#include <net/rose.h>
  34
  35/*
  36 * State machine for state 1, Awaiting Call Accepted State.
  37 * The handling of the timer(s) is in file rose_timer.c.
  38 * Handling of state 0 and connection release is in af_rose.c.
  39 */
  40static int rose_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  41{
  42        struct rose_sock *rose = rose_sk(sk);
  43
  44        switch (frametype) {
  45        case ROSE_CALL_ACCEPTED:
  46                rose_stop_timer(sk);
  47                rose_start_idletimer(sk);
  48                rose->condition = 0x00;
  49                rose->vs        = 0;
  50                rose->va        = 0;
  51                rose->vr        = 0;
  52                rose->vl        = 0;
  53                rose->state     = ROSE_STATE_3;
  54                sk->sk_state    = TCP_ESTABLISHED;
  55                if (!sock_flag(sk, SOCK_DEAD))
  56                        sk->sk_state_change(sk);
  57                break;
  58
  59        case ROSE_CLEAR_REQUEST:
  60                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  61                rose_disconnect(sk, ECONNREFUSED, skb->data[3], skb->data[4]);
  62                rose->neighbour->use--;
  63                break;
  64
  65        default:
  66                break;
  67        }
  68
  69        return 0;
  70}
  71
  72/*
  73 * State machine for state 2, Awaiting Clear Confirmation State.
  74 * The handling of the timer(s) is in file rose_timer.c
  75 * Handling of state 0 and connection release is in af_rose.c.
  76 */
  77static int rose_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  78{
  79        struct rose_sock *rose = rose_sk(sk);
  80
  81        switch (frametype) {
  82        case ROSE_CLEAR_REQUEST:
  83                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
  84                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
  85                rose->neighbour->use--;
  86                break;
  87
  88        case ROSE_CLEAR_CONFIRMATION:
  89                rose_disconnect(sk, 0, -1, -1);
  90                rose->neighbour->use--;
  91                break;
  92
  93        default:
  94                break;
  95        }
  96
  97        return 0;
  98}
  99
 100/*
 101 * State machine for state 3, Connected State.
 102 * The handling of the timer(s) is in file rose_timer.c
 103 * Handling of state 0 and connection release is in af_rose.c.
 104 */
 105static int rose_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype, int ns, int nr, int q, int d, int m)
 106{
 107        struct rose_sock *rose = rose_sk(sk);
 108        int queued = 0;
 109
 110        switch (frametype) {
 111        case ROSE_RESET_REQUEST:
 112                rose_stop_timer(sk);
 113                rose_start_idletimer(sk);
 114                rose_write_internal(sk, ROSE_RESET_CONFIRMATION);
 115                rose->condition = 0x00;
 116                rose->vs        = 0;
 117                rose->vr        = 0;
 118                rose->va        = 0;
 119                rose->vl        = 0;
 120                rose_requeue_frames(sk);
 121                break;
 122
 123        case ROSE_CLEAR_REQUEST:
 124                rose_write_internal(sk, ROSE_CLEAR_CONFIRMATION);
 125                rose_disconnect(sk, 0, skb->data[3], skb->data[4]);
 126                rose->neighbour->use--;
 127                break;
 128
 129        case ROSE_RR:
 130        case ROSE_RNR:
 131                if (!rose_validate_nr(sk, nr)) {
 132                        rose_write_internal(sk, ROSE_RESET_REQUEST);
 133                        rose->condition = 0x00;
 134                        rose->vs        = 0;
 135                        rose->vr        = 0;
 136                        rose->va        = 0;
 137                        rose->vl        = 0;
 138                        rose->state     = ROSE_STATE_4;
 139                        rose_start_t2timer(sk);
 140                        rose_stop_idletimer(sk);
 141                } else {
 142                        rose_frames_acked(sk, nr);
 143                        if (frametype == ROSE_RNR) {
 144                                rose->condition |= ROSE_COND_PEER_RX_BUSY;
 145                        } else {
 146                                rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 147                        }
 148                }
 149                break;
 150
 151        case ROSE_DATA: /* XXX */
 152                rose->condition &= ~ROSE_COND_PEER_RX_BUSY;
 153                if (!rose_validate_nr(sk, nr)) {
 154                        rose_write_internal(sk, ROSE_RESET_REQUEST);
 155                        rose->condition = 0x00;
 156                        rose->vs        = 0;
 157                        rose->vr        = 0;
 158                        rose->va        = 0;
 159                        rose->vl        = 0;
 160                        rose->state     = ROSE_STATE_4;
 161                        rose_start_t2timer(sk);
 162                        rose_stop_idletimer(sk);
 163                        break;
 164                }
 165                rose_frames_acked(sk, nr);
 166                if (ns == rose->vr) {
 167                        rose_start_idletimer(sk);
 168                        if (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