net/netrom/nr_subr.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  */
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/in.h>
  13 #include <linux/kernel.h>
  14 #include <linux/timer.h>
  15 #include <linux/string.h>
  16 #include <linux/sockios.h>
  17 #include <linux/net.h>
  18 #include <net/ax25.h>
  19 #include <linux/inet.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/skbuff.h>
  22 #include <net/sock.h>
  23 #include <net/tcp_states.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/system.h>
  26 #include <linux/fcntl.h>
  27 #include <linux/mm.h>
  28 #include <linux/interrupt.h>
  29 #include <net/netrom.h>
  30
  31 /*
  32  *      This routine purges all of the queues of frames.
  33  */
  34 void nr_clear_queues(struct sock *sk)
  35 {
  36         struct nr_sock *nr = nr_sk(sk);
  37
  38         skb_queue_purge(&sk->sk_write_queue);
  39         skb_queue_purge(&nr->ack_queue);
  40         skb_queue_purge(&nr->reseq_queue);
  41         skb_queue_purge(&nr->frag_queue);
  42 }
  43
  44 /*
  45  * This routine purges the input queue of those frames that have been
  46  * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
  47  * SDL diagram.
  48  */
  49 void nr_frames_acked(struct sock *sk, unsigned short nr)
  50 {
  51         struct nr_sock *nrom = nr_sk(sk);
  52         struct sk_buff *skb;
  53
  54         /*
  55          * Remove all the ack-ed frames from the ack queue.
  56          */
  57         if (nrom->va != nr) {
  58                 while (skb_peek(&nrom->ack_queue) != NULL && nrom->va != nr) {
  59                         skb = skb_dequeue(&nrom->ack_queue);
  60                         kfree_skb(skb);
  61                         nrom->va = (nrom->va + 1) % NR_MODULUS;
  62                 }
  63         }
  64 }
  65
  66 /*
  67  * Requeue all the un-ack-ed frames on the output queue to be picked
  68  * up by nr_kick called from the timer. This arrangement handles the
  69  * possibility of an empty output queue.
  70  */
  71 void nr_requeue_frames(struct sock *sk)
  72 {
  73         struct sk_buff *skb, *skb_prev = NULL;
  74
  75         while ((skb = skb_dequeue(&nr_sk(sk)->ack_queue)) != NULL) {
  76                 if (skb_prev == NULL)
  77                         skb_queue_head(&sk->sk_write_queue, skb);
  78                 else
  79                         skb_append(skb_prev, skb, &sk->sk_write_queue);
  80                 skb_prev = skb;
  81         }
  82 }
  83
  84 /*
  85  *      Validate that the value of nr is between va and vs. Return true or
  86  *      false for testing.
  87  */
  88 int nr_validate_nr(struct sock *sk, unsigned short nr)
  89 {
  90         struct nr_sock *nrom = nr_sk(sk);
  91         unsigned short vc = nrom->va;
  92
  93         while (vc != nrom->vs) {
  94                 if (nr == vc) return 1;
  95                 vc = (vc + 1) % NR_MODULUS;
  96         }
  97
  98         return nr == nrom->vs;
  99 }
 100
 101 /*
 102  *      Check that ns is within the receive window.
 103  */
 104 int nr_in_rx_window(struct sock *sk, unsigned short ns)
 105 {
 106         struct nr_sock *nr = nr_sk(sk);
 107         unsigned short vc = nr->vr;
 108         unsigned short vt = (nr->vl + nr->window) % NR_MODULUS;
 109
 110         while (vc != vt) {
 111                 if (ns == vc) return 1;
 112                 vc = (vc + 1) % NR_MODULUS;
 113         }
 114
 115         return 0;
 116 }
 117
 118 /*
 119  *  This routine is called when the HDLC layer internally generates a
 120  *  control frame.
 121  */
 122 void nr_write_internal(struct sock *sk, int frametype)
 123 {
 124         struct nr_sock *nr = nr_sk(sk);
 125         struct sk_buff *skb;
 126         unsigned char  *dptr;
 127         int len, timeout;
 128
 129         len = NR_NETWORK_LEN + NR_TRANSPORT_LEN;
 130
 131         switch (frametype & 0x0F) {
 132         case NR_CONNREQ:
 133                 len += 17;
 134                 break;
 135         case NR_CONNACK:
 136                 len += (nr->bpqext) ? 2 : 1;
 137                 break;
 138         case NR_DISCREQ:
 139         case NR_DISCACK:
 140         case NR_INFOACK:
 141                 break;
 142         default:
 143                 printk(KERN_ERR "NET/ROM: nr_write_internal - invalid frame type %d\n", frametype);
 144                 return;
 145         }
 146
 147         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 148                 return;
 149
 150         /*
 151          *      Space for AX.25 and NET/ROM network header
 152          */
 153         skb_reserve(skb, NR_NETWORK_LEN);
 154
 155         dptr = skb_put(skb, skb_tailroom(skb));
 156
 157         switch (frametype & 0x0F) {
 158         case NR_CONNREQ:
 159                 timeout  = nr->t1 / HZ;
 160                 *dptr++  = nr->my_index;
 161                 *dptr++  = nr->my_id;
 162                 *dptr++  = 0;
 163                 *dptr++  = 0;
 164                 *dptr++  = frametype;
 165                 *dptr++  = nr->window;
 166                 memcpy(dptr, &nr->user_addr, AX25_ADDR_LEN);
 167                 dptr[6] &= ~AX25_CBIT;
 168                 dptr[6] &= ~AX25_EBIT;
 169                 dptr[6] |= AX25_SSSID_SPARE;
 170                 dptr    += AX25_ADDR_LEN;
 171                 memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN);
 172                 dptr[6] &= ~AX25_CBIT;
 173                 dptr[6] &= ~AX25_EBIT;
 174                 dptr[6] |= AX25_SSSID_SPARE;
 175                 dptr    += AX25_ADDR_LEN;
 176                 *dptr++  = timeout % 256;
 177                 *dptr++  = timeout / 256;
 178                 break;
 179
 180         case NR_CONNACK:
 181                 *dptr++ = nr->your_index;
 182                 *dptr++ = nr->your_id;
 183                 *dptr++ = nr->my_index;
 184                 *dptr++ = nr->my_id;
 185                 *dptr++ = frametype;
 186                 *dptr++ = nr->window;
 187                 if (nr->bpqext) *dptr++ = sysctl_netrom_network_ttl_initialiser;
 188                 break;
 189
 190         case NR_DISCREQ:
 191         case NR_DISCACK:
 192                 *dptr++ = nr->your_index;
 193                 *dptr++ = nr->your_id;
 194                 *dptr++ = 0;
 195                 *dptr++ = 0;
 196                 *dptr++ = frametype;
 197                 break;
 198
 199         case NR_INFOACK:
 200                 *dptr++ = nr->your_index;
 201                 *dptr++ = nr->your_id;
 202                 *dptr++ = 0;
 203                 *dptr++ = nr->vr;
 204                 *dptr++ = frametype;
 205                 break;
 206         }
 207
 208         nr_transmit_buffer(sk, skb);
 209 }
 210
 211 /*
 212  * This routine is called to send an error reply.
 213  */
 214 void __nr_transmit_reply(struct sk_buff *skb, int mine, unsigned char cmdflags)
 215 {
 216         struct sk_buff *skbn;
 217         unsigned char *dptr;
 218         int len;
 219
 220         len = NR_NETWORK_LEN + NR_TRANSPORT_LEN + 1;
 221
 222         if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL)
 223                 return;
 224
 225         skb_reserve(skbn, 0);
 226
 227         dptr = skb_put(skbn, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
 228
 229         skb_copy_from_linear_data_offset(skb, 7, dptr, AX25_ADDR_LEN);
 230         dptr[6] &= ~AX25_CBIT;
 231         dptr[6] &= ~AX25_EBIT;
 232         dptr[6] |= AX25_SSSID_SPARE;
 233         dptr += AX25_ADDR_LEN;
 234
 235         skb_copy_from_linear_data(skb, dptr, AX25_ADDR_LEN);
 236         dptr[6] &= ~AX25_CBIT;
 237         dptr[6] |= AX25_EBIT;
 238         dptr[6] |= AX25_SSSID_SPARE;
 239         dptr += AX25_ADDR_LEN;
 240
 241         *dptr++ = sysctl_netrom_network_ttl_initialiser;
 242
 243         if (mine) {
 244                 *dptr++ = 0;
 245                 *dptr++ = 0;
 246                 *dptr++ = skb->data[15];
 247                 *dptr++ = skb->data[16];
 248         } else {
 249                 *dptr++ = skb->data[15];
 250                 *dptr++ = skb->data[16];
 251                 *dptr++ = 0;
 252                 *dptr++ = 0;
 253         }
 254
 255         *dptr++ = cmdflags;
 256         *dptr++ = 0;
 257
 258         if (!nr_route_frame(skbn, NULL))
 259                 kfree_skb(skbn);
 260 }
 261
 262 void nr_disconnect(struct sock *sk, int reason)
 263 {
 264         nr_stop_t1timer(sk);
 265         nr_stop_t2timer(sk);
 266         nr_stop_t4timer(sk);
 267         nr_stop_idletimer(sk);
 268
 269         nr_clear_queues(sk);
 270
 271         nr_sk(sk)->state = NR_STATE_0;
 272
 273         sk->sk_state     = TCP_CLOSE;
 274         sk->sk_err       = reason;
 275         sk->sk_shutdown |= SEND_SHUTDOWN;
 276
 277         if (!sock_flag(sk, SOCK_DEAD)) {
 278                 sk->sk_state_change(sk);
 279                 sock_set_flag(sk, SOCK_DEAD);
 280         }
 281 }