kernel/net/rose/rose_link.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 (C) 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/jiffies.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 <linux/fcntl.h>
  26 #include <linux/mm.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/netfilter.h>
  29 #include <net/rose.h>
  30
  31 static void rose_ftimer_expiry(unsigned long);
  32 static void rose_t0timer_expiry(unsigned long);
  33
  34 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
  35 static void rose_transmit_restart_request(struct rose_neigh *neigh);
  36
  37 void rose_start_ftimer(struct rose_neigh *neigh)
  38 {
  39         del_timer(&neigh->ftimer);
  40
  41         neigh->ftimer.data     = (unsigned long)neigh;
  42         neigh->ftimer.function = &rose_ftimer_expiry;
  43         neigh->ftimer.expires  =
  44                 jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
  45
  46         add_timer(&neigh->ftimer);
  47 }
  48
  49 static void rose_start_t0timer(struct rose_neigh *neigh)
  50 {
  51         del_timer(&neigh->t0timer);
  52
  53         neigh->t0timer.data     = (unsigned long)neigh;
  54         neigh->t0timer.function = &rose_t0timer_expiry;
  55         neigh->t0timer.expires  =
  56                 jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
  57
  58         add_timer(&neigh->t0timer);
  59 }
  60
  61 void rose_stop_ftimer(struct rose_neigh *neigh)
  62 {
  63         del_timer(&neigh->ftimer);
  64 }
  65
  66 void rose_stop_t0timer(struct rose_neigh *neigh)
  67 {
  68         del_timer(&neigh->t0timer);
  69 }
  70
  71 int rose_ftimer_running(struct rose_neigh *neigh)
  72 {
  73         return timer_pending(&neigh->ftimer);
  74 }
  75
  76 static int rose_t0timer_running(struct rose_neigh *neigh)
  77 {
  78         return timer_pending(&neigh->t0timer);
  79 }
  80
  81 static void rose_ftimer_expiry(unsigned long param)
  82 {
  83 }
  84
  85 static void rose_t0timer_expiry(unsigned long param)
  86 {
  87         struct rose_neigh *neigh = (struct rose_neigh *)param;
  88
  89         rose_transmit_restart_request(neigh);
  90
  91         neigh->dce_mode = 0;
  92
  93         rose_start_t0timer(neigh);
  94 }
  95
  96 /*
  97  *      Interface to ax25_send_frame. Changes my level 2 callsign depending
  98  *      on whether we have a global ROSE callsign or use the default port
  99  *      callsign.
 100  */
 101 static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
 102 {
 103         ax25_address *rose_call;
 104         ax25_cb *ax25s;
 105
 106         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 107                 rose_call = (ax25_address *)neigh->dev->dev_addr;
 108         else
 109                 rose_call = &rose_callsign;
 110
 111         ax25s = neigh->ax25;
 112         neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 113         if (ax25s)
 114                 ax25_cb_put(ax25s);
 115
 116         return neigh->ax25 != NULL;
 117 }
 118
 119 /*
 120  *      Interface to ax25_link_up. Changes my level 2 callsign depending
 121  *      on whether we have a global ROSE callsign or use the default port
 122  *      callsign.
 123  */
 124 static int rose_link_up(struct rose_neigh *neigh)
 125 {
 126         ax25_address *rose_call;
 127         ax25_cb *ax25s;
 128
 129         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 130                 rose_call = (ax25_address *)neigh->dev->dev_addr;
 131         else
 132                 rose_call = &rose_callsign;
 133
 134         ax25s = neigh->ax25;
 135         neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 136         if (ax25s)
 137                 ax25_cb_put(ax25s);
 138
 139         return neigh->ax25 != NULL;
 140 }
 141
 142 /*
 143  *      This handles all restart and diagnostic frames.
 144  */
 145 void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
 146 {
 147         struct sk_buff *skbn;
 148
 149         switch (frametype) {
 150         case ROSE_RESTART_REQUEST:
 151                 rose_stop_t0timer(neigh);
 152                 neigh->restarted = 1;
 153                 neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
 154                 rose_transmit_restart_confirmation(neigh);
 155                 break;
 156
 157         case ROSE_RESTART_CONFIRMATION:
 158                 rose_stop_t0timer(neigh);
 159                 neigh->restarted = 1;
 160                 break;
 161
 162         case ROSE_DIAGNOSTIC:
 163                 pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
 164                         skb->data + 4);
 165                 break;
 166
 167         default:
 168                 printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
 169                 break;
 170         }
 171
 172         if (neigh->restarted) {
 173                 while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
 174                         if (!rose_send_frame(skbn, neigh))
 175                                 kfree_skb(skbn);
 176         }
 177 }
 178
 179 /*
 180  *      This routine is called when a Restart Request is needed
 181  */
 182 static void rose_transmit_restart_request(struct rose_neigh *neigh)
 183 {
 184         struct sk_buff *skb;
 185         unsigned char *dptr;
 186         int len;
 187
 188         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 189
 190         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 191                 return;
 192
 193         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 194
 195         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 196
 197         *dptr++ = AX25_P_ROSE;
 198         *dptr++ = ROSE_GFI;
 199         *dptr++ = 0x00;
 200         *dptr++ = ROSE_RESTART_REQUEST;
 201         *dptr++ = ROSE_DTE_ORIGINATED;
 202         *dptr++ = 0;
 203
 204         if (!rose_send_frame(skb, neigh))
 205                 kfree_skb(skb);
 206 }
 207
 208 /*
 209  * This routine is called when a Restart Confirmation is needed
 210  */
 211 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
 212 {
 213         struct sk_buff *skb;
 214         unsigned char *dptr;
 215         int len;
 216
 217         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
 218
 219         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 220                 return;
 221
 222         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 223
 224         dptr = skb_put(skb, ROSE_MIN_LEN + 1);
 225
 226         *dptr++ = AX25_P_ROSE;
 227         *dptr++ = ROSE_GFI;
 228         *dptr++ = 0x00;
 229         *dptr++ = ROSE_RESTART_CONFIRMATION;
 230
 231         if (!rose_send_frame(skb, neigh))
 232                 kfree_skb(skb);
 233 }
 234
 235 /*
 236  * This routine is called when a Clear Request is needed outside of the context
 237  * of a connected socket.
 238  */
 239 void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
 240 {
 241         struct sk_buff *skb;
 242         unsigned char *dptr;
 243         int len;
 244
 245         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 246
 247         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 248                 return;
 249
 250         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 251
 252         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 253
 254         *dptr++ = AX25_P_ROSE;
 255         *dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
 256         *dptr++ = ((lci >> 0) & 0xFF);
 257         *dptr++ = ROSE_CLEAR_REQUEST;
 258         *dptr++ = cause;
 259         *dptr++ = diagnostic;
 260
 261         if (!rose_send_frame(skb, neigh))
 262                 kfree_skb(skb);
 263 }
 264
 265 void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
 266 {
 267         unsigned char *dptr;
 268
 269         if (neigh->loopback) {
 270                 rose_loopback_queue(skb, neigh);
 271                 return;
 272         }
 273
 274         if (!rose_link_up(neigh))
 275                 neigh->restarted = 0;
 276
 277         dptr = skb_push(skb, 1);
 278         *dptr++ = AX25_P_ROSE;
 279
 280         if (neigh->restarted) {
 281                 if (!rose_send_frame(skb, neigh))
 282                         kfree_skb(skb);
 283         } else {
 284                 skb_queue_tail(&neigh->queue, skb);
 285
 286                 if (!rose_t0timer_running(neigh)) {
 287                         rose_transmit_restart_request(neigh);
 288                         neigh->dce_mode = 0;
 289                         rose_start_t0timer(neigh);
 290                 }
 291         }
 292 }