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