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