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         struct nr_sock *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         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         default:
 103                 break;
 104         }
 105         return 0;
 106 }
 107
 108 /*
 109  * State machine for state 2, Awaiting Release State.
 110  * The handling of the timer(s) is in file nr_timer.c
 111  * Handling of state 0 and connection release is in netrom.c.
 112  */
 113 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 114         int frametype)
 115 {
 116         switch (frametype) {
 117         case NR_CONNACK | NR_CHOKE_FLAG:
 118                 nr_disconnect(sk, ECONNRESET);
 119                 break;
 120
 121         case NR_DISCREQ:
 122                 nr_write_internal(sk, NR_DISCACK);
 123
 124         case NR_DISCACK:
 125                 nr_disconnect(sk, 0);
 126                 break;
 127
 128         default:
 129                 break;
 130         }
 131         return 0;
 132 }
 133
 134 /*
 135  * State machine for state 3, Connected State.
 136  * The handling of the timer(s) is in file nr_timer.c
 137  * Handling of state 0 and connection release is in netrom.c.
 138  */
 139 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 140 {
 141         struct nr_sock *nrom = nr_sk(sk);
 142         struct sk_buff_head temp_queue;
 143         struct sk_buff *skbn;
 144         unsigned short save_vr;
 145         unsigned short nr, ns;
 146         int queued = 0;
 147
 148         nr = skb->data[18];
 149         ns = skb->data[17];
 150
 151         switch (frametype) {
 152         case NR_CONNREQ:
 153                 nr_write_internal(sk, NR_CONNACK);
 154                 break;
 155
 156         case NR_DISCREQ:
 157                 nr_write_internal(sk, NR_DISCACK);
 158                 nr_disconnect(sk, 0);
 159                 break;
 160
 161         case NR_CONNACK | NR_CHOKE_FLAG:
 162         case NR_DISCACK:
 163                 nr_disconnect(sk, ECONNRESET);
 164                 break;
 165
 166         case NR_INFOACK:
 167         case NR_INFOACK | NR_CHOKE_FLAG:
 168         case NR_INFOACK | NR_NAK_FLAG:
 169         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 170                 if (frametype & NR_CHOKE_FLAG) {
 171                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 172                         nr_start_t4timer(sk);
 173                 } else {
 174                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 175                         nr_stop_t4timer(sk);
 176                 }
 177                 if (!nr_validate_nr(sk, nr)) {
 178                         break;
 179                 }
 180                 if (frametype & NR_NAK_FLAG) {
 181                         nr_frames_acked(sk, nr);
 182                         nr_send_nak_frame(sk);
 183                 } else {
 184                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 185                                 nr_frames_acked(sk, nr);
 186                         } else {
 187                                 nr_check_iframes_acked(sk, nr);
 188                         }
 189                 }
 190                 break;
 191
 192         case NR_INFO:
 193         case NR_INFO | NR_NAK_FLAG:
 194         case NR_INFO | NR_CHOKE_FLAG:
 195         case NR_INFO | NR_MORE_FLAG:
 196         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 197         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 198         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 199         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 200                 if (frametype & NR_CHOKE_FLAG) {
 201                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 202                         nr_start_t4timer(sk);
 203                 } else {
 204                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 205                         nr_stop_t4timer(sk);
 206                 }
 207                 if (nr_validate_nr(sk, nr)) {
 208                         if (frametype & NR_NAK_FLAG) {
 209                                 nr_frames_acked(sk, nr);
 210                                 nr_send_nak_frame(sk);
 211                         } else {
 212                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 213                                         nr_frames_acked(sk, nr);
 214                                 } else {
 215                                         nr_check_iframes_acked(sk, nr);
 216                                 }
 217                         }
 218                 }
 219                 queued = 1;
 220                 skb_queue_head(&nrom->reseq_queue, skb);
 221                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
 222                         break;
 223                 skb_queue_head_init(&temp_queue);
 224                 do {
 225                         save_vr = nrom->vr;
 226                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 227                                 ns = skbn->data[17];
 228                                 if (ns == nrom->vr) {
 229                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 230                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 231                                         } else {
 232                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
 233                                                 skb_queue_tail(&temp_queue, skbn);
 234                                         }
 235                                 } else if (nr_in_rx_window(sk, ns)) {
 236                                         skb_queue_tail(&temp_queue, skbn);
 237                                 } else {
 238                                         kfree_skb(skbn);
 239                                 }
 240                         }
 241                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 242                                 skb_queue_tail(&nrom->reseq_queue, skbn);
 243                         }
 244                 } while (save_vr != nrom->vr);
 245                 /*
 246                  * Window is full, ack it immediately.
 247                  */
 248                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 249                         nr_enquiry_response(sk);
 250                 } else {
 251                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 252                                 nrom->condition |= NR_COND_ACK_PENDING;
 253                                 nr_start_t2timer(sk);
 254                         }
 255                 }
 256                 break;
 257
 258         default:
 259                 break;
 260         }
 261         return queued;
 262 }
 263
 264 /* Higher level upcall for a LAPB frame - called with sk locked */
 265 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 266 {
 267         struct nr_sock *nr = nr_sk(sk);
 268         int queued = 0, frametype;
 269
 270         if (nr->state == NR_STATE_0)
 271                 return 0;
 272
 273         frametype = skb->data[19];
 274
 275         switch (nr->state) {
 276         case NR_STATE_1:
 277                 queued = nr_state1_machine(sk, skb, frametype);
 278                 break;
 279         case NR_STATE_2:
 280                 queued = nr_state2_machine(sk, skb, frametype);
 281                 break;
 282         case NR_STATE_3:
 283                 queued = nr_state3_machine(sk, skb, frametype);
 284                 break;
 285         }
 286
 287         nr_kick(sk);
 288
 289         return queued;
 290 }