LXR linux-old/net/netrom/nr

   1/*
   2 *      NET/ROM release 007
   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 *      NET/ROM 001     Jonathan(G4KLX) Cloned from ax25_in.c
  20 *      NET/ROM 003     Jonathan(G4KLX) Added NET/ROM fragment reception.
  21 *                      Darryl(G7LED)   Added missing INFO with NAK case, optimized
  22 *                                      INFOACK handling, removed reconnect on error.
  23 *      NET/ROM 006     Jonathan(G4KLX) Hdrincl removal changes.
  24 *      NET/ROM 007     Jonathan(G4KLX) New timer architecture.
  25 */
  26
  27#include <linux/errno.h>
  28#include <linux/types.h>
  29#include <linux/socket.h>
  30#include <linux/in.h>
  31#include <linux/kernel.h>
  32#include <linux/sched.h>
  33#include <linux/timer.h>
  34#include <linux/string.h>
  35#include <linux/sockios.h>
  36#include <linux/net.h>
  37#include <net/ax25.h>
  38#include <linux/inet.h>
  39#include <linux/netdevice.h>
  40#include <linux/skbuff.h>
  41#include <net/sock.h>
  42#include <net/ip.h>                     /* For ip_rcv */
  43#include <asm/uaccess.h>
  44#include <asm/system.h>
  45#include <linux/fcntl.h>
  46#include <linux/mm.h>
  47#include <linux/interrupt.h>
  48#include <net/netrom.h>
  49
  50static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  51{
  52        struct sk_buff *skbo, *skbn = skb;
  53
  54        skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  55
  56        nr_start_idletimer(sk);
  57
  58        if (more) {
  59                sk->protinfo.nr->fraglen += skb->len;
  60                skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
  61                return 0;
  62        }
  63
  64        if (!more && sk->protinfo.nr->fraglen > 0) {    /* End of fragment */
  65                sk->protinfo.nr->fraglen += skb->len;
  66                skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
  67
  68                if ((skbn = alloc_skb(sk->protinfo.nr->fraglen, GFP_ATOMIC)) == NULL)
  69                        return 1;
  70
  71                skbn->h.raw = skbn->data;
  72
  73                while ((skbo = skb_dequeue(&sk->protinfo.nr->frag_queue)) != NULL) {
  74                        memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
  75                        kfree_skb(skbo);
  76                }
  77
  78                sk->protinfo.nr->fraglen = 0;           
  79        }
  80
  81        return sock_queue_rcv_skb(sk, skbn);
  82}
  83
  84/*
  85 * State machine for state 1, Awaiting Connection State.
  86 * The handling of the timer(s) is in file nr_timer.c.
  87 * Handling of state 0 and connection release is in netrom.c.
  88 */
  89static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
  90{
  91        switch (frametype) {
  92
  93                case NR_CONNACK:
  94                        nr_stop_t1timer(sk);
  95                        nr_start_idletimer(sk);
  96                        sk->protinfo.nr->your_index = skb->data[17];
  97                        sk->protinfo.nr->your_id    = skb->data[18];
  98                        sk->protinfo.nr->vs         = 0;
  99                        sk->protinfo.nr->va         = 0;
 100                        sk->protinfo.nr->vr         = 0;
 101                        sk->protinfo.nr->vl         = 0;
 102                        sk->protinfo.nr->state      = NR_STATE_3;
 103                        sk->protinfo.nr->n2count    = 0;
 104                        sk->protinfo.nr->window     = skb->data[20];
 105                        sk->state                   = TCP_ESTABLISHED;
 106                        if (!sk->dead)
 107                                sk->state_change(sk);
 108                        break;
 109
 110                case NR_CONNACK | NR_CHOKE_FLAG:
 111                        nr_disconnect(sk, ECONNREFUSED);
 112                        break;
 113
 114                default:
 115                        break;
 116        }
 117
 118        return 0;
 119}
 120
 121/*
 122 * State machine for state 2, Awaiting Release State.
 123 * The handling of the timer(s) is in file nr_timer.c
 124 * Handling of state 0 and connection release is in netrom.c.
 125 */
 126static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 127{
 128        switch (frametype) {
 129
 130                case NR_CONNACK | NR_CHOKE_FLAG:
 131                        nr_disconnect(sk, ECONNRESET);
 132                        break;
 133
 134                case NR_DISCREQ:
 135                        nr_write_internal(sk, NR_DISCACK);
 136
 137                case NR_DISCACK:
 138                        nr_disconnect(sk, 0);
 139                        break;
 140
 141                default:
 142                        break;
 143        }
 144
 145        return 0;
 146}
 147
 148/*
 149 * State machine for state 3, Connected State.
 150 * The handling of the timer(s) is in file nr_timer.c
 151 * Handling of state 0 and connection release is in netrom.c.
 152 */
 153static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 154{
 155        struct sk_buff_head temp_queue;
 156        struct sk_buff *skbn;
 157        unsigned short save_vr;
 158        unsigned short nr, ns;
 159        int queued = 0;
 160
 161        nr = skb->data[18];
 162        ns = skb->data[17];
 163
 164        switch (frametype) {
 165
 166                case NR_CONNREQ:
 167                        nr_write_internal(sk, NR_CONNACK);
 168                        break;
 169
 170                case NR_DISCREQ:
 171                        nr_write_internal(sk, NR_DISCACK);
 172                        nr_disconnect(sk, 0);
 173                        break;
 174
 175                case NR_CONNACK | NR_CHOKE_FLAG:
 176                case NR_DISCACK:
 177                        nr_disconnect(sk, ECONNRESET);
 178                        break;
 179
 180                case NR_INFOACK:
 181                case NR_INFOACK | NR_CHOKE_FLAG:
 182                case NR_INFOACK | NR_NAK_FLAG:
 183                case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 184                        if (frametype & NR_CHOKE_FLAG) {
 185                                sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
 186                                nr_start_t4timer(sk);
 187                        } else {
 188                                sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
 189                                nr_stop_t4timer(sk);
 190                        }
 191                        if (!nr_validate_nr(sk, nr)) {
 192                                break;
 193                        }
 194                        if (frametype & NR_NAK_FLAG) {
 195                                nr_frames_acked(sk, nr);
 196                                nr_send_nak_frame(sk);
 197                        } else {
 198                                if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
 199                                        nr_frames_acked(sk, nr);
 200                                } else {
 201                                        nr_check_iframes_acked(sk, nr);
 202                                }
 203                        }
 204                        break;
 205
 206                case NR_INFO:
 207                case NR_INFO | NR_NAK_FLAG:
 208                case NR_INFO | NR_CHOKE_FLAG:
 209                case NR_INFO | NR_MORE_FLAG:
 210                case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 211                case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 212                case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 213                case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 214                        if (frametype & NR_CHOKE_FLAG) {
 215                                sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
 216                                nr_start_t4timer(sk);
 217                        } else {
 218                                sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
 219                                nr_stop_t4timer(sk);
 220                        }
 221                        if (nr_validate_nr(sk, nr)) {
 222                                if (frametype & NR_NAK_FLAG) {
 223                                        nr_frames_acked(sk, nr);
 224                                        nr_send_nak_frame(sk);
 225                                } else {
 226                                        if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
 227                                                nr_frames_acked(sk, nr);
 228                                        } else {
 229                                                nr_check_iframes_acked(sk, nr);
 230                                        }
 231                                }
 232                        }
 233                        queued = 1;
 234                        skb_queue_head(&sk->protinfo.nr->reseq_queue, skb);
 235                        if (sk->protinfo.nr->condition & NR_COND_OWN_RX_BUSY)
 236                                break;
 237                        skb_queue_head_init(&temp_queue);
 238                        do {
 239                                save_vr = sk->protinfo.nr->vr;
 240                                while ((skbn = skb_dequeue(&sk->protinfo.nr->reseq_queue)) != NULL) {
 241                                        ns = skbn->data[17];
 242                                        if (ns == sk->protinfo.nr->vr) {
 243                                                if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 244                                                        sk->protinfo.nr->vr = (sk->protinfo.nr->vr + 1) % NR_MODULUS;
 245                                                } else {
 246                                                        sk->protinfo.nr->condition |= NR_COND_OWN_RX_BUSY;
 247                                                        skb_queue_tail(&temp_queue, skbn);
 248                                                }
 249                                        } else if (nr_in_rx_window(sk, ns)) {
 250                                                skb_queue_tail(&temp_queue, skbn);
 251                                        } else {
 252                                                kfree_skb(skbn);
 253                                        }
 254                                }
 255                                while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 256                                        skb_queue_tail(&sk->protinfo.nr->reseq_queue, skbn);
 257                                }
 258                        } while (save_vr != sk->protinfo.nr->vr);
 259                        /*
 260                         * Window is full, ack it immediately.
 261                         */
 262                        if (((sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS) == sk->protinfo.nr->vr) {
 263                                nr_enquiry_response(sk);
 264                        } else {
 265                                if (!(sk->protinfo.nr->condition & NR_COND_ACK_PENDING)) {
 266                                        sk->protinfo.nr->condition |= NR_COND_ACK_PENDING;
 267                                        nr_start_t2timer(sk);
 268                                }
 269                        }
 270                        break;
 271
 272                default:
 273                        break;
 274        }
 275
 276        return queued;
 277}
 278
 279/* Higher level upcall for a LAPB frame */
 280int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 281{
 282        int queued = 0, frametype;
 283
 284        if (sk->protinfo.nr->state == NR_STATE_0)
 285                return 0;
 286
 287        frametype = skb->data[19];
 288
 289        switch (sk->protinfo.nr->state) {
 290                case NR_STATE_1:
 291                        queued = nr_state1_machine(sk, skb, frametype);
 292                        break;
 293                case NR_STATE_2:
 294                        queued = nr_state2_machine(sk, skb, frametype);
 295                        break;
 296                case NR_STATE_3:
 297                        queued = nr_state3_machine(sk, skb, frametype);
 298                        break;
 299        }
 300
 301        nr_kick(sk);
 302
 303        return queued;
 304}
 305