net/netrom/nr_subr.c

   1 /*
   2  *      NET/ROM release 007
   3  *
   4  *      This code REQUIRES 2.1.15 or higher/ NET3.038
   5  *
   6  *      This module:
   7  *              This module is free software; you can redistribute it and/or
   8  *              modify it under the terms of the GNU General Public License
   9  *              as published by the Free Software Foundation; either version
  10  *              2 of the License, or (at your option) any later version.
  11  *
  12  *      History
  13  *      NET/ROM 001     Jonathan(G4KLX) Cloned from ax25_subr.c
  14  *      NET/ROM 003     Jonathan(G4KLX) Added G8BPQ NET/ROM extensions.
  15  *      NET/ROM 007     Jonathan(G4KLX) New timer architecture.
  16  */
  17
  18 #include <linux/errno.h>
  19 #include <linux/types.h>
  20 #include <linux/socket.h>
  21 #include <linux/in.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/timer.h>
  25 #include <linux/string.h>
  26 #include <linux/sockios.h>
  27 #include <linux/net.h>
  28 #include <net/ax25.h>
  29 #include <linux/inet.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/skbuff.h>
  32 #include <net/sock.h>
  33 #include <asm/uaccess.h>
  34 #include <asm/system.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/mm.h>
  37 #include <linux/interrupt.h>
  38 #include <net/netrom.h>
  39
  40 /*
  41  *      This routine purges all of the queues of frames.
  42  */
  43 void nr_clear_queues(struct sock *sk)
  44 {
  45         skb_queue_purge(&sk->write_queue);
  46         skb_queue_purge(&sk->protinfo.nr->ack_queue);
  47         skb_queue_purge(&sk->protinfo.nr->reseq_queue);
  48         skb_queue_purge(&sk->protinfo.nr->frag_queue);
  49 }
  50
  51 /*
  52  * This routine purges the input queue of those frames that have been
  53  * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
  54  * SDL diagram.
  55  */
  56 void nr_frames_acked(struct sock *sk, unsigned short nr)
  57 {
  58         struct sk_buff *skb;
  59
  60         /*
  61          * Remove all the ack-ed frames from the ack queue.
  62          */
  63         if (sk->protinfo.nr->va != nr) {
  64                 while (skb_peek(&sk->protinfo.nr->ack_queue) != NULL && sk->protinfo.nr->va != nr) {
  65                         skb = skb_dequeue(&sk->protinfo.nr->ack_queue);
  66                         kfree_skb(skb);
  67                         sk->protinfo.nr->va = (sk->protinfo.nr->va + 1) % NR_MODULUS;
  68                 }
  69         }
  70 }
  71
  72 /*
  73  * Requeue all the un-ack-ed frames on the output queue to be picked
  74  * up by nr_kick called from the timer. This arrangement handles the
  75  * possibility of an empty output queue.
  76  */
  77 void nr_requeue_frames(struct sock *sk)
  78 {
  79         struct sk_buff *skb, *skb_prev = NULL;
  80
  81         while ((skb = skb_dequeue(&sk->protinfo.nr->ack_queue)) != NULL) {
  82                 if (skb_prev == NULL)
  83                         skb_queue_head(&sk->write_queue, skb);
  84                 else
  85                         skb_append(skb_prev, skb);
  86                 skb_prev = skb;
  87         }
  88 }
  89
  90 /*
  91  *      Validate that the value of nr is between va and vs. Return true or
  92  *      false for testing.
  93  */
  94 int nr_validate_nr(struct sock *sk, unsigned short nr)
  95 {
  96         unsigned short vc = sk->protinfo.nr->va;
  97
  98         while (vc != sk->protinfo.nr->vs) {
  99                 if (nr == vc) return 1;
 100                 vc = (vc + 1) % NR_MODULUS;
 101         }
 102
 103         if (nr == sk->protinfo.nr->vs) return 1;
 104
 105         return 0;
 106 }
 107
 108 /*
 109  *      Check that ns is within the receive window.
 110  */
 111 int nr_in_rx_window(struct sock *sk, unsigned short ns)
 112 {
 113         unsigned short vc = sk->protinfo.nr->vr;
 114         unsigned short vt = (sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS;
 115
 116         while (vc != vt) {
 117                 if (ns == vc) return 1;
 118                 vc = (vc + 1) % NR_MODULUS;
 119         }
 120
 121         return 0;
 122 }
 123
 124 /*
 125  *  This routine is called when the HDLC layer internally generates a
 126  *  control frame.
 127  */
 128 void nr_write_internal(struct sock *sk, int frametype)
 129 {
 130         struct sk_buff *skb;
 131         unsigned char  *dptr;
 132         int len, timeout;
 133
 134         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + NR_NETWORK_LEN + NR_TRANSPORT_LEN;
 135
 136         switch (frametype & 0x0F) {
 137                 case NR_CONNREQ:
 138                         len += 17;
 139                         break;
 140                 case NR_CONNACK:
 141                         len += (sk->protinfo.nr->bpqext) ? 2 : 1;
 142                         break;
 143                 case NR_DISCREQ:
 144                 case NR_DISCACK:
 145                 case NR_INFOACK:
 146                         break;
 147                 default:
 148                         printk(KERN_ERR "NET/ROM: nr_write_internal - invalid frame type %d\n", frametype);
 149                         return;
 150         }
 151
 152         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 153                 return;
 154
 155         /*
 156          *      Space for AX.25 and NET/ROM network header
 157          */
 158         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + NR_NETWORK_LEN);
 159
 160         dptr = skb_put(skb, skb_tailroom(skb));
 161
 162         switch (frametype & 0x0F) {
 163
 164                 case NR_CONNREQ:
 165                         timeout  = sk->protinfo.nr->t1 / HZ;
 166                         *dptr++  = sk->protinfo.nr->my_index;
 167                         *dptr++  = sk->protinfo.nr->my_id;
 168                         *dptr++  = 0;
 169                         *dptr++  = 0;
 170                         *dptr++  = frametype;
 171                         *dptr++  = sk->protinfo.nr->window;
 172                         memcpy(dptr, &sk->protinfo.nr->user_addr, AX25_ADDR_LEN);
 173                         dptr[6] &= ~AX25_CBIT;
 174                         dptr[6] &= ~AX25_EBIT;
 175                         dptr[6] |= AX25_SSSID_SPARE;
 176                         dptr    += AX25_ADDR_LEN;
 177                         memcpy(dptr, &sk->protinfo.nr->source_addr, AX25_ADDR_LEN);
 178                         dptr[6] &= ~AX25_CBIT;
 179                         dptr[6] &= ~AX25_EBIT;
 180                         dptr[6] |= AX25_SSSID_SPARE;
 181                         dptr    += AX25_ADDR_LEN;
 182                         *dptr++  = timeout % 256;
 183                         *dptr++  = timeout / 256;
 184                         break;
 185
 186                 case NR_CONNACK:
 187                         *dptr++ = sk->protinfo.nr->your_index;
 188                         *dptr++ = sk->protinfo.nr->your_id;
 189                         *dptr++ = sk->protinfo.nr->my_index;
 190                         *dptr++ = sk->protinfo.nr->my_id;
 191                         *dptr++ = frametype;
 192                         *dptr++ = sk->protinfo.nr->window;
 193                         if (sk->protinfo.nr->bpqext) *dptr++ = sysctl_netrom_network_ttl_initialiser;
 194                         break;
 195
 196                 case NR_DISCREQ:
 197                 case NR_DISCACK:
 198                         *dptr++ = sk->protinfo.nr->your_index;
 199                         *dptr++ = sk->protinfo.nr->your_id;
 200                         *dptr++ = 0;
 201                         *dptr++ = 0;
 202                         *dptr++ = frametype;
 203                         break;
 204
 205                 case NR_INFOACK:
 206                         *dptr++ = sk->protinfo.nr->your_index;
 207                         *dptr++ = sk->protinfo.nr->your_id;
 208                         *dptr++ = 0;
 209                         *dptr++ = sk->protinfo.nr->vr;
 210                         *dptr++ = frametype;
 211                         break;
 212         }
 213
 214         nr_transmit_buffer(sk, skb);
 215 }
 216
 217 /*
 218  * This routine is called when a Connect Acknowledge with the Choke Flag
 219  * set is needed to refuse a connection.
 220  */
 221 void nr_transmit_refusal(struct sk_buff *skb, int mine)
 222 {
 223         struct sk_buff *skbn;
 224         unsigned char *dptr;
 225         int len;
 226
 227         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + NR_NETWORK_LEN + NR_TRANSPORT_LEN + 1;
 228
 229         if ((skbn = alloc_skb(len, GFP_ATOMIC)) == NULL)
 230                 return;
 231
 232         skb_reserve(skbn, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 233
 234         dptr = skb_put(skbn, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
 235
 236         memcpy(dptr, skb->data + 7, AX25_ADDR_LEN);
 237         dptr[6] &= ~AX25_CBIT;
 238         dptr[6] &= ~AX25_EBIT;
 239         dptr[6] |= AX25_SSSID_SPARE;
 240         dptr += AX25_ADDR_LEN;
 241
 242         memcpy(dptr, skb->data + 0, AX25_ADDR_LEN);
 243         dptr[6] &= ~AX25_CBIT;
 244         dptr[6] |= AX25_EBIT;
 245         dptr[6] |= AX25_SSSID_SPARE;
 246         dptr += AX25_ADDR_LEN;
 247
 248         *dptr++ = sysctl_netrom_network_ttl_initialiser;
 249
 250         if (mine) {
 251                 *dptr++ = 0;
 252                 *dptr++ = 0;
 253                 *dptr++ = skb->data[15];
 254                 *dptr++ = skb->data[16];
 255         } else {
 256                 *dptr++ = skb->data[15];
 257                 *dptr++ = skb->data[16];
 258                 *dptr++ = 0;
 259                 *dptr++ = 0;
 260         }
 261
 262         *dptr++ = NR_CONNACK | NR_CHOKE_FLAG;
 263         *dptr++ = 0;
 264
 265         if (!nr_route_frame(skbn, NULL))
 266                 kfree_skb(skbn);
 267 }
 268
 269 void nr_disconnect(struct sock *sk, int reason)
 270 {
 271         nr_stop_t1timer(sk);
 272         nr_stop_t2timer(sk);
 273         nr_stop_t4timer(sk);
 274         nr_stop_idletimer(sk);
 275
 276         nr_clear_queues(sk);
 277
 278         sk->protinfo.nr->state = NR_STATE_0;
 279
 280         sk->state     = TCP_CLOSE;
 281         sk->err       = reason;
 282         sk->shutdown |= SEND_SHUTDOWN;
 283
 284         if (!sk->dead)
 285                 sk->state_change(sk);
 286
 287         sk->dead = 1;
 288 }