net/netrom/nr_in.c

   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 <linux/fcntl.h>
  28 #include <linux/mm.h>
  29 #include <linux/interrupt.h>
  30 #include <net/netrom.h>
  31
  32 static 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  */
  74 static 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  */
 118 static 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  */
 149 static 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 */
 280 int 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 }