linux/net/netrom/nr_subr.c
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   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 <linux/slab.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 <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 */
  34void 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 */
  49void 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 */
  71void 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 */
  88int 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 */
 104int 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 */
 122void 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 */
 214void __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
 262void 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}
 282
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