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.h>
  26 #include <net/ip.h>                     /* For ip_rcv */
  27 #include <asm/uaccess.h>
  28 #include <asm/system.h>
  29 #include <linux/fcntl.h>
  30 #include <linux/mm.h>
  31 #include <linux/interrupt.h>
  32 #include <net/netrom.h>
  33
  34 static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
  35 {
  36         struct sk_buff *skbo, *skbn = skb;
  37         nr_cb *nr = nr_sk(sk);
  38
  39         skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
  40
  41         nr_start_idletimer(sk);
  42
  43         if (more) {
  44                 nr->fraglen += skb->len;
  45                 skb_queue_tail(&nr->frag_queue, skb);
  46                 return 0;
  47         }
  48
  49         if (!more && nr->fraglen > 0) { /* End of fragment */
  50                 nr->fraglen += skb->len;
  51                 skb_queue_tail(&nr->frag_queue, skb);
  52
  53                 if ((skbn = alloc_skb(nr->fraglen, GFP_ATOMIC)) == NULL)
  54                         return 1;
  55
  56                 skbn->h.raw = skbn->data;
  57
  58                 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
  59                         memcpy(skb_put(skbn, skbo->len), skbo->data, 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         bh_lock_sock(sk);
  78         switch (frametype) {
  79         case NR_CONNACK: {
  80                 nr_cb *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         default:
 104                 break;
 105         }
 106         bh_unlock_sock(sk);
 107
 108         return 0;
 109 }
 110
 111 /*
 112  * State machine for state 2, Awaiting Release State.
 113  * The handling of the timer(s) is in file nr_timer.c
 114  * Handling of state 0 and connection release is in netrom.c.
 115  */
 116 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 117         int frametype)
 118 {
 119         bh_lock_sock(sk);
 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         default:
 133                 break;
 134         }
 135         bh_unlock_sock(sk);
 136
 137         return 0;
 138 }
 139
 140 /*
 141  * State machine for state 3, Connected State.
 142  * The handling of the timer(s) is in file nr_timer.c
 143  * Handling of state 0 and connection release is in netrom.c.
 144  */
 145 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 146 {
 147         nr_cb *nrom = nr_sk(sk);
 148         struct sk_buff_head temp_queue;
 149         struct sk_buff *skbn;
 150         unsigned short save_vr;
 151         unsigned short nr, ns;
 152         int queued = 0;
 153
 154         nr = skb->data[18];
 155         ns = skb->data[17];
 156
 157         bh_lock_sock(sk);
 158         switch (frametype) {
 159         case NR_CONNREQ:
 160                 nr_write_internal(sk, NR_CONNACK);
 161                 break;
 162
 163         case NR_DISCREQ:
 164                 nr_write_internal(sk, NR_DISCACK);
 165                 nr_disconnect(sk, 0);
 166                 break;
 167
 168         case NR_CONNACK | NR_CHOKE_FLAG:
 169         case NR_DISCACK:
 170                 nr_disconnect(sk, ECONNRESET);
 171                 break;
 172
 173         case NR_INFOACK:
 174         case NR_INFOACK | NR_CHOKE_FLAG:
 175         case NR_INFOACK | NR_NAK_FLAG:
 176         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 177                 if (frametype & NR_CHOKE_FLAG) {
 178                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 179                         nr_start_t4timer(sk);
 180                 } else {
 181                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 182                         nr_stop_t4timer(sk);
 183                 }
 184                 if (!nr_validate_nr(sk, nr)) {
 185                         break;
 186                 }
 187                 if (frametype & NR_NAK_FLAG) {
 188                         nr_frames_acked(sk, nr);
 189                         nr_send_nak_frame(sk);
 190                 } else {
 191                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 192                                 nr_frames_acked(sk, nr);
 193                         } else {
 194                                 nr_check_iframes_acked(sk, nr);
 195                         }
 196                 }
 197                 break;
 198
 199         case NR_INFO:
 200         case NR_INFO | NR_NAK_FLAG:
 201         case NR_INFO | NR_CHOKE_FLAG:
 202         case NR_INFO | NR_MORE_FLAG:
 203         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 204         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 205         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 206         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 207                 if (frametype & NR_CHOKE_FLAG) {
 208                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 209                         nr_start_t4timer(sk);
 210                 } else {
 211                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 212                         nr_stop_t4timer(sk);
 213                 }
 214                 if (nr_validate_nr(sk, nr)) {
 215                         if (frametype & NR_NAK_FLAG) {
 216                                 nr_frames_acked(sk, nr);
 217                                 nr_send_nak_frame(sk);
 218                         } else {
 219                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 220                                         nr_frames_acked(sk, nr);
 221                                 } else {
 222                                         nr_check_iframes_acked(sk, nr);
 223                                 }
 224                         }
 225                 }
 226                 queued = 1;
 227                 skb_queue_head(&nrom->reseq_queue, skb);
 228                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
 229                         break;
 230                 skb_queue_head_init(&temp_queue);
 231                 do {
 232                         save_vr = nrom->vr;
 233                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 234                                 ns = skbn->data[17];
 235                                 if (ns == nrom->vr) {
 236                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 237                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 238                                         } else {
 239                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
 240                                                 skb_queue_tail(&temp_queue, skbn);
 241                                         }
 242                                 } else if (nr_in_rx_window(sk, ns)) {
 243                                         skb_queue_tail(&temp_queue, skbn);
 244                                 } else {
 245                                         kfree_skb(skbn);
 246                                 }
 247                         }
 248                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 249                                 skb_queue_tail(&nrom->reseq_queue, skbn);
 250                         }
 251                 } while (save_vr != nrom->vr);
 252                 /*
 253                  * Window is full, ack it immediately.
 254                  */
 255                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 256                         nr_enquiry_response(sk);
 257                 } else {
 258                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 259                                 nrom->condition |= NR_COND_ACK_PENDING;
 260                                 nr_start_t2timer(sk);
 261                         }
 262                 }
 263                 break;
 264
 265         default:
 266                 break;
 267         }
 268         bh_unlock_sock(sk);
 269
 270         return queued;
 271 }
 272
 273 /* Higher level upcall for a LAPB frame */
 274 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 275 {
 276         nr_cb *nr = nr_sk(sk);
 277         int queued = 0, frametype;
 278
 279         if (nr->state == NR_STATE_0)
 280                 return 0;
 281
 282         frametype = skb->data[19];
 283
 284         switch (nr->state) {
 285         case NR_STATE_1:
 286                 queued = nr_state1_machine(sk, skb, frametype);
 287                 break;
 288         case NR_STATE_2:
 289                 queued = nr_state2_machine(sk, skb, frametype);
 290                 break;
 291         case NR_STATE_3:
 292                 queued = nr_state3_machine(sk, skb, frametype);
 293                 break;
 294         }
 295
 296         nr_kick(sk);
 297
 298         return queued;
 299 }