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         default:
 102                 break;
 103         }
 104         return 0;
 105 }
 106
 107 /*
 108  * State machine for state 2, Awaiting Release State.
 109  * The handling of the timer(s) is in file nr_timer.c
 110  * Handling of state 0 and connection release is in netrom.c.
 111  */
 112 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 113         int frametype)
 114 {
 115         switch (frametype) {
 116         case NR_CONNACK | NR_CHOKE_FLAG:
 117                 nr_disconnect(sk, ECONNRESET);
 118                 break;
 119
 120         case NR_DISCREQ:
 121                 nr_write_internal(sk, NR_DISCACK);
 122
 123         case NR_DISCACK:
 124                 nr_disconnect(sk, 0);
 125                 break;
 126
 127         default:
 128                 break;
 129         }
 130         return 0;
 131 }
 132
 133 /*
 134  * State machine for state 3, Connected State.
 135  * The handling of the timer(s) is in file nr_timer.c
 136  * Handling of state 0 and connection release is in netrom.c.
 137  */
 138 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 139 {
 140         struct nr_sock *nrom = nr_sk(sk);
 141         struct sk_buff_head temp_queue;
 142         struct sk_buff *skbn;
 143         unsigned short save_vr;
 144         unsigned short nr, ns;
 145         int queued = 0;
 146
 147         nr = skb->data[18];
 148         ns = skb->data[17];
 149
 150         switch (frametype) {
 151         case NR_CONNREQ:
 152                 nr_write_internal(sk, NR_CONNACK);
 153                 break;
 154
 155         case NR_DISCREQ:
 156                 nr_write_internal(sk, NR_DISCACK);
 157                 nr_disconnect(sk, 0);
 158                 break;
 159
 160         case NR_CONNACK | NR_CHOKE_FLAG:
 161         case NR_DISCACK:
 162                 nr_disconnect(sk, ECONNRESET);
 163                 break;
 164
 165         case NR_INFOACK:
 166         case NR_INFOACK | NR_CHOKE_FLAG:
 167         case NR_INFOACK | NR_NAK_FLAG:
 168         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 169                 if (frametype & NR_CHOKE_FLAG) {
 170                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 171                         nr_start_t4timer(sk);
 172                 } else {
 173                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 174                         nr_stop_t4timer(sk);
 175                 }
 176                 if (!nr_validate_nr(sk, nr)) {
 177                         break;
 178                 }
 179                 if (frametype & NR_NAK_FLAG) {
 180                         nr_frames_acked(sk, nr);
 181                         nr_send_nak_frame(sk);
 182                 } else {
 183                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 184                                 nr_frames_acked(sk, nr);
 185                         } else {
 186                                 nr_check_iframes_acked(sk, nr);
 187                         }
 188                 }
 189                 break;
 190
 191         case NR_INFO:
 192         case NR_INFO | NR_NAK_FLAG:
 193         case NR_INFO | NR_CHOKE_FLAG:
 194         case NR_INFO | NR_MORE_FLAG:
 195         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 196         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 197         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 198         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 199                 if (frametype & NR_CHOKE_FLAG) {
 200                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 201                         nr_start_t4timer(sk);
 202                 } else {
 203                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 204                         nr_stop_t4timer(sk);
 205                 }
 206                 if (nr_validate_nr(sk, nr)) {
 207                         if (frametype & NR_NAK_FLAG) {
 208                                 nr_frames_acked(sk, nr);
 209                                 nr_send_nak_frame(sk);
 210                         } else {
 211                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 212                                         nr_frames_acked(sk, nr);
 213                                 } else {
 214                                         nr_check_iframes_acked(sk, nr);
 215                                 }
 216                         }
 217                 }
 218                 queued = 1;
 219                 skb_queue_head(&nrom->reseq_queue, skb);
 220                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
 221                         break;
 222                 skb_queue_head_init(&temp_queue);
 223                 do {
 224                         save_vr = nrom->vr;
 225                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 226                                 ns = skbn->data[17];
 227                                 if (ns == nrom->vr) {
 228                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 229                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 230                                         } else {
 231                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
 232                                                 skb_queue_tail(&temp_queue, skbn);
 233                                         }
 234                                 } else if (nr_in_rx_window(sk, ns)) {
 235                                         skb_queue_tail(&temp_queue, skbn);
 236                                 } else {
 237                                         kfree_skb(skbn);
 238                                 }
 239                         }
 240                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 241                                 skb_queue_tail(&nrom->reseq_queue, skbn);
 242                         }
 243                 } while (save_vr != nrom->vr);
 244                 /*
 245                  * Window is full, ack it immediately.
 246                  */
 247                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 248                         nr_enquiry_response(sk);
 249                 } else {
 250                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 251                                 nrom->condition |= NR_COND_ACK_PENDING;
 252                                 nr_start_t2timer(sk);
 253                         }
 254                 }
 255                 break;
 256
 257         default:
 258                 break;
 259         }
 260         return queued;
 261 }
 262
 263 /* Higher level upcall for a LAPB frame - called with sk locked */
 264 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 265 {
 266         struct nr_sock *nr = nr_sk(sk);
 267         int queued = 0, frametype;
 268
 269         if (nr->state == NR_STATE_0)
 270                 return 0;
 271
 272         frametype = skb->data[19];
 273
 274         switch (nr->state) {
 275         case NR_STATE_1:
 276                 queued = nr_state1_machine(sk, skb, frametype);
 277                 break;
 278         case NR_STATE_2:
 279                 queued = nr_state2_machine(sk, skb, frametype);
 280                 break;
 281         case NR_STATE_3:
 282                 queued = nr_state3_machine(sk, skb, frametype);
 283                 break;
 284         }
 285
 286         nr_kick(sk);
 287
 288         return queued;
 289 }