LXR linux/net/netrom/nr

   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 Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8 * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
   9 */
  10#include <linux/errno.h>
  11#include <linux/types.h>
  12#include <linux/socket.h>
  13#include <linux/in.h>
  14#include <linux/kernel.h>
  15#include <linux/timer.h>
  16#include <linux/string.h>
  17#include <linux/sockios.h>
  18#include <linux/net.h>
  19#include <net/ax25.h>
  20#include <linux/inet.h>
  21#include <linux/netdevice.h>
  22#include <linux/skbuff.h>
  23#include <net/sock.h>
  24#include <net/tcp_states.h>
  25#include <asm/uaccess.h>
  26#include <asm/system.h>
  27#include <linux/fcntl.h>
  28#include <linux/mm.h>
  29#include <linux/interrupt.h>
  30#include <net/netrom.h>
  31
  32static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  33{
  34        struct sk_buff *skbo, *skbn = skb;
  35        struct nr_sock *nr = nr_sk(sk);
  36
  37        skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  38
  39        nr_start_idletimer(sk);
  40
  41        if (more) {
  42                nr->fraglen += skb->len;
  43                skb_queue_tail(&nr->frag_queue, skb);
  44                return 0;
  45        }
  46
  47        if (!more && nr->fraglen > 0) { /* End of fragment */
  48                nr->fraglen += skb->len;
  49                skb_queue_tail(&nr->frag_queue, skb);
  50
  51                if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
  52                        return 1;
  53
  54                skb_reset_transport_header(skbn);
  55
  56                while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
  57                        skb_copy_from_linear_data(skbo,
  58                                                  skb_put(skbn, skbo->len),
  59                                                  skbo->len);
  60                        kfree_skb(skbo);
  61                }
  62
  63                nr->fraglen = 0;
  64        }
  65
  66        return sock_queue_rcv_skb(sk, skbn);
  67}
  68
  69/*
  70 * State machine for state 1, Awaiting Connection State.
  71 * The handling of the timer(s) is in file nr_timer.c.
  72 * Handling of state 0 and connection release is in netrom.c.
  73 */
  74static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
  75        int frametype)
  76{
  77        switch (frametype) {
  78        case NR_CONNACK: {
  79                struct nr_sock *nr = nr_sk(sk);
  80
  81                nr_stop_t1timer(sk);
  82                nr_start_idletimer(sk);
  83                nr->your_index = skb->data[17];
  84                nr->your_id    = skb->data[18];
  85                nr->vs         = 0;
  86                nr->va         = 0;
  87                nr->vr         = 0;
  88                nr->vl         = 0;
  89                nr->state      = NR_STATE_3;
  90                nr->n2count    = 0;
  91                nr->window     = skb->data[20];
  92                sk->sk_state   = TCP_ESTABLISHED;
  93                if (!sock_flag(sk, SOCK_DEAD))
  94                        sk->sk_state_change(sk);
  95                break;
  96        }
  97
  98        case NR_CONNACK | NR_CHOKE_FLAG:
  99                nr_disconnect(sk, ECONNREFUSED);
 100                break;
 101
 102        case NR_RESET:
 103                if (sysctl_netrom_reset_circuit)
 104                        nr_disconnect(sk, ECONNRESET);
 105                break;
 106
 107        default:
 108                break;
 109        }
 110        return 0;
 111}
 112
 113/*
 114 * State machine for state 2, Awaiting Release State.
 115 * The handling of the timer(s) is in file nr_timer.c
 116 * Handling of state 0 and connection release is in netrom.c.
 117 */
 118static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 119        int frametype)
 120{
 121        switch (frametype) {
 122        case NR_CONNACK | NR_CHOKE_FLAG:
 123                nr_disconnect(sk, ECONNRESET);
 124                break;
 125
 126        case NR_DISCREQ:
 127                nr_write_internal(sk, NR_DISCACK);
 128
 129        case NR_DISCACK:
 130                nr_disconnect(sk, 0);
 131                break;
 132
 133        case NR_RESET:
 134                if (sysctl_netrom_reset_circuit)
 135                        nr_disconnect(sk, ECONNRESET);
 136                break;
 137
 138        default:
 139                break;
 140        }
 141        return 0;
 142}
 143
 144/*
 145 * State machine for state 3, Connected State.
 146 * The handling of the timer(s) is in file nr_timer.c
 147 * Handling of state 0 and connection release is in netrom.c.
 148 */
 149static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 150{
 151        struct nr_sock *nrom = nr_sk(sk);
 152        struct sk_buff_head temp_queue;
 153        struct sk_buff *skbn;
 154        unsigned short save_vr;
 155        unsigned short nr, ns;
 156        int queued = 0;
 157
 158        nr = skb->data[18];
 159        ns = skb->data[17];
 160
 161        switch (frametype) {
 162        case NR_CONNREQ:
 163                nr_write_internal(sk, NR_CONNACK);
 164                break;
 165
 166        case NR_DISCREQ:
 167                nr_write_internal(sk, NR_DISCACK);
 168                nr_disconnect(sk, 0);
 169                break;
 170
 171        case NR_CONNACK | NR_CHOKE_FLAG:
 172        case NR_DISCACK:
 173                nr_disconnect(sk, ECONNRESET);
 174                break;
 175
 176        case NR_INFOACK:
 177        case NR_INFOACK | NR_CHOKE_FLAG:
 178        case NR_INFOACK | NR_NAK_FLAG:
 179        case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 180                if (frametype & NR_CHOKE_FLAG) {
 181                        nrom->condition |= NR_COND_PEER_RX_BUSY;
 182                        nr_start_t4timer(sk);
 183                } else {
 184                        nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 185                        nr_stop_t4timer(sk);
 186                }
 187                if (!nr_validate_nr(sk, nr)) {
 188                        break;
 189                }
 190                if (frametype & NR_NAK_FLAG) {
 191                        nr_frames_acked(sk, nr);
 192                        nr_send_nak_frame(sk);
 193                } else {
 194                        if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 195                                nr_frames_acked(sk, nr);
 196                        } else {
 197                                nr_check_iframes_acked(sk, nr);
 198                        }
 199                }
 200                break;
 201
 202        case NR_INFO:
 203        case NR_INFO | NR_NAK_FLAG:
 204        case NR_INFO | NR_CHOKE_FLAG:
 205        case NR_INFO | NR_MORE_FLAG:
 206        case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 207        case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 208        case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 209        case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 210                if (frametype & NR_CHOKE_FLAG) {
 211                        nrom->condition |= NR_COND_PEER_RX_BUSY;
 212                        nr_start_t4timer(sk);
 213                } else {
 214                        nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 215                        nr_stop_t4timer(sk);
 216                }
 217                if (nr_validate_nr(sk, nr)) {
 218                        if (frametype & NR_NAK_FLAG) {
 219                                nr_frames_acked(sk, nr);
 220                                nr_send_nak_frame(sk);
 221                        } else {
 222                                if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 223                                        nr_frames_acked(sk, nr);
 224                                } else {
 225                                        nr_check_iframes_acked(sk, nr);
 226                                }
 227                        }
 228                }
 229                queued = 1;
 230                skb_queue_head(&nrom->reseq_queue, skb);
 231                if (nrom->condition & NR_COND_OWN_RX_BUSY)
 232                        break;
 233                skb_queue_head_init(&temp_queue);
 234                do {
 235                        save_vr = nrom->vr;
 236                        while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 237                                ns = skbn->data[17];
 238                                if (ns == nrom->vr) {
 239                                        if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 240                                                nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 241                                        } else {
 242                                                nrom->condition |= NR_COND_OWN_RX_BUSY;
 243                                                skb_queue_tail(&temp_queue, skbn);
 244                                        }
 245                                } else if (nr_in_rx_window(sk, ns)) {
 246                                        skb_queue_tail(&temp_queue, skbn);
 247                                } else {
 248                                        kfree_skb(skbn);
 249                                }
 250                        }
 251                        while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 252                                skb_queue_tail(&nrom->reseq_queue, skbn);
 253                        }
 254                } while (save_vr != nrom->vr);
 255                /*
 256                 * Window is full, ack it immediately.
 257                 */
 258                if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 259                        nr_enquiry_response(sk);
 260                } else {
 261                        if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 262                                nrom->condition |= NR_COND_ACK_PENDING;
 263                                nr_start_t2timer(sk);
 264                        }
 265                }
 266                break;
 267
 268        case NR_RESET:
 269                if (sysctl_netrom_reset_circuit)
 270                        nr_disconnect(sk, ECONNRESET);
 271                break;
 272
 273        default:
 274                break;
 275        }
 276        return queued;
 277}
 278
 279/* Higher level upcall for a LAPB frame - called with sk locked */
 280int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 281{
 282        struct nr_sock *nr = nr_sk(sk);
 283        int queued = 0, frametype;
 284
 285        if (nr->state == NR_STATE_0)
 286                return 0;
 287
 288        frametype = skb->data[19];
 289
 290        switch (nr->state) {
 291        case NR_STATE_1:
 292                queued = nr_state1_machine(sk, skb, frametype);
 293                break;
 294        case NR_STATE_2:
 295                queued = nr_state2_machine(sk, skb, frametype);
 296                break;
 297        case NR_STATE_3:
 298                queued = nr_state3_machine(sk, skb, frametype);
 299                break;
 300        }
 301
 302        nr_kick(sk);
 303
 304        return queued;
 305}
 306