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 <net/ax25.h>
  20 #include <linux/inet.h>
  21 #include <linux/netdevice.h>
  22 #include <linux/skbuff.h>
  23 #include <net/sock.h>
  24 #include <net/tcp_states.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/system.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                 skbn->h.raw = skbn->data;
  55
  56                 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
  57                         memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
  58                         kfree_skb(skbo);
  59                 }
  60
  61                 nr->fraglen = 0;
  62         }
  63
  64         return sock_queue_rcv_skb(sk, skbn);
  65 }
  66
  67 /*
  68  * State machine for state 1, Awaiting Connection State.
  69  * The handling of the timer(s) is in file nr_timer.c.
  70  * Handling of state 0 and connection release is in netrom.c.
  71  */
  72 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
  73         int frametype)
  74 {
  75         switch (frametype) {
  76         case NR_CONNACK: {
  77                 struct nr_sock *nr = nr_sk(sk);
  78
  79                 nr_stop_t1timer(sk);
  80                 nr_start_idletimer(sk);
  81                 nr->your_index = skb->data[17];
  82                 nr->your_id    = skb->data[18];
  83                 nr->vs         = 0;
  84                 nr->va         = 0;
  85                 nr->vr         = 0;
  86                 nr->vl         = 0;
  87                 nr->state      = NR_STATE_3;
  88                 nr->n2count    = 0;
  89                 nr->window     = skb->data[20];
  90                 sk->sk_state   = TCP_ESTABLISHED;
  91                 if (!sock_flag(sk, SOCK_DEAD))
  92                         sk->sk_state_change(sk);
  93                 break;
  94         }
  95
  96         case NR_CONNACK | NR_CHOKE_FLAG:
  97                 nr_disconnect(sk, ECONNREFUSED);
  98                 break;
  99
 100         case NR_RESET:
 101                 if (sysctl_netrom_reset_circuit)
 102                         nr_disconnect(sk, ECONNRESET);
 103                 break;
 104
 105         default:
 106                 break;
 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         switch (frametype) {
 120         case NR_CONNACK | NR_CHOKE_FLAG:
 121                 nr_disconnect(sk, ECONNRESET);
 122                 break;
 123
 124         case NR_DISCREQ:
 125                 nr_write_internal(sk, NR_DISCACK);
 126
 127         case NR_DISCACK:
 128                 nr_disconnect(sk, 0);
 129                 break;
 130
 131         case NR_RESET:
 132                 if (sysctl_netrom_reset_circuit)
 133                         nr_disconnect(sk, ECONNRESET);
 134                 break;
 135
 136         default:
 137                 break;
 138         }
 139         return 0;
 140 }
 141
 142 /*
 143  * State machine for state 3, Connected State.
 144  * The handling of the timer(s) is in file nr_timer.c
 145  * Handling of state 0 and connection release is in netrom.c.
 146  */
 147 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 148 {
 149         struct nr_sock *nrom = nr_sk(sk);
 150         struct sk_buff_head temp_queue;
 151         struct sk_buff *skbn;
 152         unsigned short save_vr;
 153         unsigned short nr, ns;
 154         int queued = 0;
 155
 156         nr = skb->data[18];
 157         ns = skb->data[17];
 158
 159         switch (frametype) {
 160         case NR_CONNREQ:
 161                 nr_write_internal(sk, NR_CONNACK);
 162                 break;
 163
 164         case NR_DISCREQ:
 165                 nr_write_internal(sk, NR_DISCACK);
 166                 nr_disconnect(sk, 0);
 167                 break;
 168
 169         case NR_CONNACK | NR_CHOKE_FLAG:
 170         case NR_DISCACK:
 171                 nr_disconnect(sk, ECONNRESET);
 172                 break;
 173
 174         case NR_INFOACK:
 175         case NR_INFOACK | NR_CHOKE_FLAG:
 176         case NR_INFOACK | NR_NAK_FLAG:
 177         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 178                 if (frametype & NR_CHOKE_FLAG) {
 179                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 180                         nr_start_t4timer(sk);
 181                 } else {
 182                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 183                         nr_stop_t4timer(sk);
 184                 }
 185                 if (!nr_validate_nr(sk, nr)) {
 186                         break;
 187                 }
 188                 if (frametype & NR_NAK_FLAG) {
 189                         nr_frames_acked(sk, nr);
 190                         nr_send_nak_frame(sk);
 191                 } else {
 192                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 193                                 nr_frames_acked(sk, nr);
 194                         } else {
 195                                 nr_check_iframes_acked(sk, nr);
 196                         }
 197                 }
 198                 break;
 199
 200         case NR_INFO:
 201         case NR_INFO | NR_NAK_FLAG:
 202         case NR_INFO | NR_CHOKE_FLAG:
 203         case NR_INFO | NR_MORE_FLAG:
 204         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 205         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 206         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 207         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 208                 if (frametype & NR_CHOKE_FLAG) {
 209                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 210                         nr_start_t4timer(sk);
 211                 } else {
 212                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 213                         nr_stop_t4timer(sk);
 214                 }
 215                 if (nr_validate_nr(sk, nr)) {
 216                         if (frametype & NR_NAK_FLAG) {
 217                                 nr_frames_acked(sk, nr);
 218                                 nr_send_nak_frame(sk);
 219                         } else {
 220                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 221                                         nr_frames_acked(sk, nr);
 222                                 } else {
 223                                         nr_check_iframes_acked(sk, nr);
 224                                 }
 225                         }
 226                 }
 227                 queued = 1;
 228                 skb_queue_head(&nrom->reseq_queue, skb);
 229                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
 230                         break;
 231                 skb_queue_head_init(&temp_queue);
 232                 do {
 233                         save_vr = nrom->vr;
 234                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 235                                 ns = skbn->data[17];
 236                                 if (ns == nrom->vr) {
 237                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 238                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 239                                         } else {
 240                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
 241                                                 skb_queue_tail(&temp_queue, skbn);
 242                                         }
 243                                 } else if (nr_in_rx_window(sk, ns)) {
 244                                         skb_queue_tail(&temp_queue, skbn);
 245                                 } else {
 246                                         kfree_skb(skbn);
 247                                 }
 248                         }
 249                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 250                                 skb_queue_tail(&nrom->reseq_queue, skbn);
 251                         }
 252                 } while (save_vr != nrom->vr);
 253                 /*
 254                  * Window is full, ack it immediately.
 255                  */
 256                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 257                         nr_enquiry_response(sk);
 258                 } else {
 259                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 260                                 nrom->condition |= NR_COND_ACK_PENDING;
 261                                 nr_start_t2timer(sk);
 262                         }
 263                 }
 264                 break;
 265
 266         case NR_RESET:
 267                 if (sysctl_netrom_reset_circuit)
 268                         nr_disconnect(sk, ECONNRESET);
 269                 break;
 270
 271         default:
 272                 break;
 273         }
 274         return queued;
 275 }
 276
 277 /* Higher level upcall for a LAPB frame - called with sk locked */
 278 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 279 {
 280         struct nr_sock *nr = nr_sk(sk);
 281         int queued = 0, frametype;
 282
 283         if (nr->state == NR_STATE_0)
 284                 return 0;
 285
 286         frametype = skb->data[19];
 287
 288         switch (nr->state) {
 289         case NR_STATE_1:
 290                 queued = nr_state1_machine(sk, skb, frametype);
 291                 break;
 292         case NR_STATE_2:
 293                 queued = nr_state2_machine(sk, skb, frametype);
 294                 break;
 295         case NR_STATE_3:
 296                 queued = nr_state3_machine(sk, skb, frametype);
 297                 break;
 298         }
 299
 300         nr_kick(sk);
 301
 302         return queued;
 303 }