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 <linux/slab.h>
  20#include <net/ax25.h>
  21#include <linux/inet.h>
  22#include <linux/netdevice.h>
  23#include <linux/skbuff.h>
  24#include <net/sock.h>
  25#include <net/tcp_states.h>
  26#include <asm/uaccess.h>
  27#include <asm/system.h>
  28#include <linux/fcntl.h>
  29#include <linux/mm.h>
  30#include <linux/interrupt.h>
  31#include <net/netrom.h>
  32
  33static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  34{
  35        struct sk_buff *skbo, *skbn = skb;
  36        struct nr_sock *nr = nr_sk(sk);
  37
  38        skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  39
  40        nr_start_idletimer(sk);
  41
  42        if (more) {
  43                nr->fraglen += skb->len;
  44                skb_queue_tail(&nr->frag_queue, skb);
  45                return 0;
  46        }
  47
  48        if (!more && nr->fraglen > 0) { /* End of fragment */
  49                nr->fraglen += skb->len;
  50                skb_queue_tail(&nr->frag_queue, skb);
  51
  52                if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
  53                        return 1;
  54
  55                skb_reset_transport_header(skbn);
  56
  57                while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
  58                        skb_copy_from_linear_data(skbo,
  59                                                  skb_put(skbn, skbo->len),
  60                                                  skbo->len);
  61                        kfree_skb(skbo);
  62                }
  63
  64                nr->fraglen = 0;
  65        }
  66
  67        return sock_queue_rcv_skb(sk, skbn);
  68}
  69
  70/*
  71 * State machine for state 1, Awaiting Connection State.
  72 * The handling of the timer(s) is in file nr_timer.c.
  73 * Handling of state 0 and connection release is in netrom.c.
  74 */
  75static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
  76        int frametype)
  77{
  78        switch (frametype) {
  79        case NR_CONNACK: {
  80                struct nr_sock *nr = nr_sk(sk);
  81
  82                nr_stop_t1timer(sk);
  83                nr_start_idletimer(sk);
  84                nr->your_index = skb->data[17];
  85                nr->your_id    = skb->data[18];
  86                nr->vs         = 0;
  87                nr->va         = 0;
  88                nr->vr         = 0;
  89                nr->vl         = 0;
  90                nr->state      = NR_STATE_3;
  91                nr->n2count    = 0;
  92                nr->window     = skb->data[20];
  93                sk->sk_state   = TCP_ESTABLISHED;
  94                if (!sock_flag(sk, SOCK_DEAD))
  95                        sk->sk_state_change(sk);
  96                break;
  97        }
  98
  99        case NR_CONNACK | NR_CHOKE_FLAG:
 100                nr_disconnect(sk, ECONNREFUSED);
 101                break;
 102
 103        case NR_RESET:
 104                if (sysctl_netrom_reset_circuit)
 105                        nr_disconnect(sk, ECONNRESET);
 106                break;
 107
 108        default:
 109                break;
 110        }
 111        return 0;
 112}
 113
 114/*
 115 * State machine for state 2, Awaiting Release State.
 116 * The handling of the timer(s) is in file nr_timer.c
 117 * Handling of state 0 and connection release is in netrom.c.
 118 */
 119static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 120        int frametype)
 121{
 122        switch (frametype) {
 123        case NR_CONNACK | NR_CHOKE_FLAG:
 124                nr_disconnect(sk, ECONNRESET);
 125                break;
 126
 127        case NR_DISCREQ:
 128                nr_write_internal(sk, NR_DISCACK);
 129
 130        case NR_DISCACK:
 131                nr_disconnect(sk, 0);
 132                break;
 133
 134        case NR_RESET:
 135                if (sysctl_netrom_reset_circuit)
 136                        nr_disconnect(sk, ECONNRESET);
 137                break;
 138
 139        default:
 140                break;
 141        }
 142        return 0;
 143}
 144
 145/*
 146 * State machine for state 3, Connected State.
 147 * The handling of the timer(s) is in file nr_timer.c
 148 * Handling of state 0 and connection release is in netrom.c.
 149 */
 150static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 151{
 152        struct nr_sock *nrom = nr_sk(sk);
 153        struct sk_buff_head temp_queue;
 154        struct sk_buff *skbn;
 155        unsigned short save_vr;
 156        unsigned short nr, ns;
 157        int queued = 0;
 158
 159        nr = skb->data[18];
 160        ns = skb->data[17];
 161
 162        switch (frametype) {
 163        case NR_CONNREQ:
 164                nr_write_internal(sk, NR_CONNACK);
 165                break;
 166
 167        case NR_DISCREQ:
 168                nr_write_internal(sk, NR_DISCACK);
 169                nr_disconnect(sk, 0);
 170                break;
 171
 172        case NR_CONNACK | NR_CHOKE_FLAG:
 173        case NR_DISCACK:
 174                nr_disconnect(sk, ECONNRESET);
 175                break;
 176
 177        case NR_INFOACK:
 178        case NR_INFOACK | NR_CHOKE_FLAG:
 179        case NR_INFOACK | NR_NAK_FLAG:
 180        case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 181                if (frametype & NR_CHOKE_FLAG) {
 182                        nrom->condition |= NR_COND_PEER_RX_BUSY;
 183                        nr_start_t4timer(sk);
 184                } else {
 185                        nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 186                        nr_stop_t4timer(sk);
 187                }
 188                if (!nr_validate_nr(sk, nr)) {
 189                        break;
 190                }
 191                if (frametype & NR_NAK_FLAG) {
 192                        nr_frames_acked(sk, nr);
 193                        nr_send_nak_frame(sk);
 194                } else {
 195                        if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 196                                nr_frames_acked(sk, nr);
 197                        } else {
 198                                nr_check_iframes_acked(sk, nr);
 199                        }
 200                }
 201                break;
 202
 203        case NR_INFO:
 204        case NR_INFO | NR_NAK_FLAG:
 205        case NR_INFO | NR_CHOKE_FLAG:
 206        case NR_INFO | NR_MORE_FLAG:
 207        case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 208        case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 209        case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 210        case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 211                if (frametype & NR_CHOKE_FLAG) {
 212                        nrom->condition |= NR_COND_PEER_RX_BUSY;
 213                        nr_start_t4timer(sk);
 214                } else {
 215                        nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 216                        nr_stop_t4timer(sk);
 217                }
 218                if (nr_validate_nr(sk, nr)) {
 219                        if (frametype & NR_NAK_FLAG) {
 220                                nr_frames_acked(sk, nr);
 221                                nr_send_nak_frame(sk);
 222                        } else {
 223                                if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 224                                        nr_frames_acked(sk, nr);
 225                                } else {
 226                                        nr_check_iframes_acked(sk, nr);
 227                                }
 228                        }
 229                }
 230                queued = 1;
 231                skb_queue_head(&nrom->reseq_queue, skb);
 232                if (nrom->condition & NR_COND_OWN_RX_BUSY)
 233                        break;
 234                skb_queue_head_init(&temp_queue);
 235                do {
 236                        save_vr = nrom->vr;
 237                        while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 238                                ns = skbn->data[17];
 239                                if (ns == nrom->vr) {
 240                                        if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 241                                                nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 242                                        } else {
 243                                                nrom->condition |= NR_COND_OWN_RX_BUSY;
 244                                                skb_queue_tail(&temp_queue, skbn);
 245                                        }
 246                                } else if (nr_in_rx_window(sk, ns)) {
 247                                        skb_queue_tail(&temp_queue, skbn);
 248                                } else {
 249                                        kfree_skb(skbn);
 250                                }
 251                        }
 252                        while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 253                                skb_queue_tail(&nrom->reseq_queue, skbn);
 254                        }
 255                } while (save_vr != nrom->vr);
 256                /*
 257                 * Window is full, ack it immediately.
 258                 */
 259                if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 260                        nr_enquiry_response(sk);
 261                } else {
 262                        if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 263                                nrom->condition |= NR_COND_ACK_PENDING;
 264                                nr_start_t2timer(sk);
 265                        }
 266                }
 267                break;
 268
 269        case NR_RESET:
 270                if (sysctl_netrom_reset_circuit)
 271                        nr_disconnect(sk, ECONNRESET);
 272                break;
 273
 274        default:
 275                break;
 276        }
 277        return queued;
 278}
 279
 280/* Higher level upcall for a LAPB frame - called with sk locked */
 281int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 282{
 283        struct nr_sock *nr = nr_sk(sk);
 284        int queued = 0, frametype;
 285
 286        if (nr->state == NR_STATE_0)
 287                return 0;
 288
 289        frametype = skb->data[19];
 290
 291        switch (nr->state) {
 292        case NR_STATE_1:
 293                queued = nr_state1_machine(sk, skb, frametype);
 294                break;
 295        case NR_STATE_2:
 296                queued = nr_state2_machine(sk, skb, frametype);
 297                break;
 298        case NR_STATE_3:
 299                queued = nr_state3_machine(sk, skb, frametype);
 300                break;
 301        }
 302
 303        nr_kick(sk);
 304
 305        return queued;
 306}
 307