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