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 ([email protected])
   8  * Copyright Darryl Miles G7LED ([email protected])
   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 <linux/slab.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                 skb_reset_transport_header(skbn);
  56
  57                 while ((skbo = skb_dequeue(&nr->frag_queue)) != NULL) {
  58                         skb_copy_from_linear_data(skbo,
  59                                                   skb_put(skbn, skbo->len),
  60                                                   skbo->len);
  61                         kfree_skb(skbo);
  62                 }
  63
  64                 nr->fraglen = 0;
  65         }
  66
  67         return sock_queue_rcv_skb(sk, skbn);
  68 }
  69
  70 /*
  71  * State machine for state 1, Awaiting Connection State.
  72  * The handling of the timer(s) is in file nr_timer.c.
  73  * Handling of state 0 and connection release is in netrom.c.
  74  */
  75 static int nr_state1_machine(struct sock *sk, struct sk_buff *skb,
  76         int frametype)
  77 {
  78         switch (frametype) {
  79         case NR_CONNACK: {
  80                 struct nr_sock *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         case NR_RESET:
 104                 if (sysctl_netrom_reset_circuit)
 105                         nr_disconnect(sk, ECONNRESET);
 106                 break;
 107
 108         default:
 109                 break;
 110         }
 111         return 0;
 112 }
 113
 114 /*
 115  * State machine for state 2, Awaiting Release State.
 116  * The handling of the timer(s) is in file nr_timer.c
 117  * Handling of state 0 and connection release is in netrom.c.
 118  */
 119 static int nr_state2_machine(struct sock *sk, struct sk_buff *skb,
 120         int frametype)
 121 {
 122         switch (frametype) {
 123         case NR_CONNACK | NR_CHOKE_FLAG:
 124                 nr_disconnect(sk, ECONNRESET);
 125                 break;
 126
 127         case NR_DISCREQ:
 128                 nr_write_internal(sk, NR_DISCACK);
 129
 130         case NR_DISCACK:
 131                 nr_disconnect(sk, 0);
 132                 break;
 133
 134         case NR_RESET:
 135                 if (sysctl_netrom_reset_circuit)
 136                         nr_disconnect(sk, ECONNRESET);
 137                 break;
 138
 139         default:
 140                 break;
 141         }
 142         return 0;
 143 }
 144
 145 /*
 146  * State machine for state 3, Connected State.
 147  * The handling of the timer(s) is in file nr_timer.c
 148  * Handling of state 0 and connection release is in netrom.c.
 149  */
 150 static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
 151 {
 152         struct nr_sock *nrom = nr_sk(sk);
 153         struct sk_buff_head temp_queue;
 154         struct sk_buff *skbn;
 155         unsigned short save_vr;
 156         unsigned short nr, ns;
 157         int queued = 0;
 158
 159         nr = skb->data[18];
 160         ns = skb->data[17];
 161
 162         switch (frametype) {
 163         case NR_CONNREQ:
 164                 nr_write_internal(sk, NR_CONNACK);
 165                 break;
 166
 167         case NR_DISCREQ:
 168                 nr_write_internal(sk, NR_DISCACK);
 169                 nr_disconnect(sk, 0);
 170                 break;
 171
 172         case NR_CONNACK | NR_CHOKE_FLAG:
 173         case NR_DISCACK:
 174                 nr_disconnect(sk, ECONNRESET);
 175                 break;
 176
 177         case NR_INFOACK:
 178         case NR_INFOACK | NR_CHOKE_FLAG:
 179         case NR_INFOACK | NR_NAK_FLAG:
 180         case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
 181                 if (frametype & NR_CHOKE_FLAG) {
 182                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 183                         nr_start_t4timer(sk);
 184                 } else {
 185                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 186                         nr_stop_t4timer(sk);
 187                 }
 188                 if (!nr_validate_nr(sk, nr)) {
 189                         break;
 190                 }
 191                 if (frametype & NR_NAK_FLAG) {
 192                         nr_frames_acked(sk, nr);
 193                         nr_send_nak_frame(sk);
 194                 } else {
 195                         if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 196                                 nr_frames_acked(sk, nr);
 197                         } else {
 198                                 nr_check_iframes_acked(sk, nr);
 199                         }
 200                 }
 201                 break;
 202
 203         case NR_INFO:
 204         case NR_INFO | NR_NAK_FLAG:
 205         case NR_INFO | NR_CHOKE_FLAG:
 206         case NR_INFO | NR_MORE_FLAG:
 207         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
 208         case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
 209         case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
 210         case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
 211                 if (frametype & NR_CHOKE_FLAG) {
 212                         nrom->condition |= NR_COND_PEER_RX_BUSY;
 213                         nr_start_t4timer(sk);
 214                 } else {
 215                         nrom->condition &= ~NR_COND_PEER_RX_BUSY;
 216                         nr_stop_t4timer(sk);
 217                 }
 218                 if (nr_validate_nr(sk, nr)) {
 219                         if (frametype & NR_NAK_FLAG) {
 220                                 nr_frames_acked(sk, nr);
 221                                 nr_send_nak_frame(sk);
 222                         } else {
 223                                 if (nrom->condition & NR_COND_PEER_RX_BUSY) {
 224                                         nr_frames_acked(sk, nr);
 225                                 } else {
 226                                         nr_check_iframes_acked(sk, nr);
 227                                 }
 228                         }
 229                 }
 230                 queued = 1;
 231                 skb_queue_head(&nrom->reseq_queue, skb);
 232                 if (nrom->condition & NR_COND_OWN_RX_BUSY)
 233                         break;
 234                 skb_queue_head_init(&temp_queue);
 235                 do {
 236                         save_vr = nrom->vr;
 237                         while ((skbn = skb_dequeue(&nrom->reseq_queue)) != NULL) {
 238                                 ns = skbn->data[17];
 239                                 if (ns == nrom->vr) {
 240                                         if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
 241                                                 nrom->vr = (nrom->vr + 1) % NR_MODULUS;
 242                                         } else {
 243                                                 nrom->condition |= NR_COND_OWN_RX_BUSY;
 244                                                 skb_queue_tail(&temp_queue, skbn);
 245                                         }
 246                                 } else if (nr_in_rx_window(sk, ns)) {
 247                                         skb_queue_tail(&temp_queue, skbn);
 248                                 } else {
 249                                         kfree_skb(skbn);
 250                                 }
 251                         }
 252                         while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
 253                                 skb_queue_tail(&nrom->reseq_queue, skbn);
 254                         }
 255                 } while (save_vr != nrom->vr);
 256                 /*
 257                  * Window is full, ack it immediately.
 258                  */
 259                 if (((nrom->vl + nrom->window) % NR_MODULUS) == nrom->vr) {
 260                         nr_enquiry_response(sk);
 261                 } else {
 262                         if (!(nrom->condition & NR_COND_ACK_PENDING)) {
 263                                 nrom->condition |= NR_COND_ACK_PENDING;
 264                                 nr_start_t2timer(sk);
 265                         }
 266                 }
 267                 break;
 268
 269         case NR_RESET:
 270                 if (sysctl_netrom_reset_circuit)
 271                         nr_disconnect(sk, ECONNRESET);
 272                 break;
 273
 274         default:
 275                 break;
 276         }
 277         return queued;
 278 }
 279
 280 /* Higher level upcall for a LAPB frame - called with sk locked */
 281 int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
 282 {
 283         struct nr_sock *nr = nr_sk(sk);
 284         int queued = 0, frametype;
 285
 286         if (nr->state == NR_STATE_0)
 287                 return 0;
 288
 289         frametype = skb->data[19];
 290
 291         switch (nr->state) {
 292         case NR_STATE_1:
 293                 queued = nr_state1_machine(sk, skb, frametype);
 294                 break;
 295         case NR_STATE_2:
 296                 queued = nr_state2_machine(sk, skb, frametype);
 297                 break;
 298         case NR_STATE_3:
 299                 queued = nr_state3_machine(sk, skb, frametype);
 300                 break;
 301         }
 302
 303         nr_kick(sk);
 304
 305         return queued;
 306 }