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 <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 <asm/system.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  = 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  = jiffies + sysctl_rose_restart_request_timeout;
  55
  56         add_timer(&neigh->t0timer);
  57 }
  58
  59 void rose_stop_ftimer(struct rose_neigh *neigh)
  60 {
  61         del_timer(&neigh->ftimer);
  62 }
  63
  64 void rose_stop_t0timer(struct rose_neigh *neigh)
  65 {
  66         del_timer(&neigh->t0timer);
  67 }
  68
  69 int rose_ftimer_running(struct rose_neigh *neigh)
  70 {
  71         return timer_pending(&neigh->ftimer);
  72 }
  73
  74 static int rose_t0timer_running(struct rose_neigh *neigh)
  75 {
  76         return timer_pending(&neigh->t0timer);
  77 }
  78
  79 static void rose_ftimer_expiry(unsigned long param)
  80 {
  81 }
  82
  83 static void rose_t0timer_expiry(unsigned long param)
  84 {
  85         struct rose_neigh *neigh = (struct rose_neigh *)param;
  86
  87         rose_transmit_restart_request(neigh);
  88
  89         neigh->dce_mode = 0;
  90
  91         rose_start_t0timer(neigh);
  92 }
  93
  94 /*
  95  *      Interface to ax25_send_frame. Changes my level 2 callsign depending
  96  *      on whether we have a global ROSE callsign or use the default port
  97  *      callsign.
  98  */
  99 static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
 100 {
 101         ax25_address *rose_call;
 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         neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 109
 110         return (neigh->ax25 != NULL);
 111 }
 112
 113 /*
 114  *      Interface to ax25_link_up. Changes my level 2 callsign depending
 115  *      on whether we have a global ROSE callsign or use the default port
 116  *      callsign.
 117  */
 118 static int rose_link_up(struct rose_neigh *neigh)
 119 {
 120         ax25_address *rose_call;
 121
 122         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 123                 rose_call = (ax25_address *)neigh->dev->dev_addr;
 124         else
 125                 rose_call = &rose_callsign;
 126
 127         neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 128
 129         return (neigh->ax25 != NULL);
 130 }
 131
 132 /*
 133  *      This handles all restart and diagnostic frames.
 134  */
 135 void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
 136 {
 137         struct sk_buff *skbn;
 138
 139         switch (frametype) {
 140         case ROSE_RESTART_REQUEST:
 141                 rose_stop_t0timer(neigh);
 142                 neigh->restarted = 1;
 143                 neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
 144                 rose_transmit_restart_confirmation(neigh);
 145                 break;
 146
 147         case ROSE_RESTART_CONFIRMATION:
 148                 rose_stop_t0timer(neigh);
 149                 neigh->restarted = 1;
 150                 break;
 151
 152         case ROSE_DIAGNOSTIC:
 153                 printk(KERN_WARNING "ROSE: received diagnostic #%d - %02X %02X %02X\n", skb->data[3], skb->data[4], skb->data[5], skb->data[6]);
 154                 break;
 155
 156         default:
 157                 printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
 158                 break;
 159         }
 160
 161         if (neigh->restarted) {
 162                 while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
 163                         if (!rose_send_frame(skbn, neigh))
 164                                 kfree_skb(skbn);
 165         }
 166 }
 167
 168 /*
 169  *      This routine is called when a Restart Request is needed
 170  */
 171 static void rose_transmit_restart_request(struct rose_neigh *neigh)
 172 {
 173         struct sk_buff *skb;
 174         unsigned char *dptr;
 175         int len;
 176
 177         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 178
 179         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 180                 return;
 181
 182         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 183
 184         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 185
 186         *dptr++ = AX25_P_ROSE;
 187         *dptr++ = ROSE_GFI;
 188         *dptr++ = 0x00;
 189         *dptr++ = ROSE_RESTART_REQUEST;
 190         *dptr++ = ROSE_DTE_ORIGINATED;
 191         *dptr++ = 0;
 192
 193         if (!rose_send_frame(skb, neigh))
 194                 kfree_skb(skb);
 195 }
 196
 197 /*
 198  * This routine is called when a Restart Confirmation is needed
 199  */
 200 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
 201 {
 202         struct sk_buff *skb;
 203         unsigned char *dptr;
 204         int len;
 205
 206         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
 207
 208         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 209                 return;
 210
 211         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 212
 213         dptr = skb_put(skb, ROSE_MIN_LEN + 1);
 214
 215         *dptr++ = AX25_P_ROSE;
 216         *dptr++ = ROSE_GFI;
 217         *dptr++ = 0x00;
 218         *dptr++ = ROSE_RESTART_CONFIRMATION;
 219
 220         if (!rose_send_frame(skb, neigh))
 221                 kfree_skb(skb);
 222 }
 223
 224 /*
 225  * This routine is called when a Clear Request is needed outside of the context
 226  * of a connected socket.
 227  */
 228 void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
 229 {
 230         struct sk_buff *skb;
 231         unsigned char *dptr;
 232         int len;
 233
 234         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 235
 236         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 237                 return;
 238
 239         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 240
 241         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 242
 243         *dptr++ = AX25_P_ROSE;
 244         *dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
 245         *dptr++ = ((lci >> 0) & 0xFF);
 246         *dptr++ = ROSE_CLEAR_REQUEST;
 247         *dptr++ = cause;
 248         *dptr++ = diagnostic;
 249
 250         if (!rose_send_frame(skb, neigh))
 251                 kfree_skb(skb);
 252 }
 253
 254 void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
 255 {
 256         unsigned char *dptr;
 257
 258 #if 0
 259         if (call_fw_firewall(PF_ROSE, skb->dev, skb->data, NULL, &skb) != FW_ACCEPT) {
 260                 kfree_skb(skb);
 261                 return;
 262         }
 263 #endif
 264
 265         if (neigh->loopback) {
 266                 rose_loopback_queue(skb, neigh);
 267                 return;
 268         }
 269
 270         if (!rose_link_up(neigh))
 271                 neigh->restarted = 0;
 272
 273         dptr = skb_push(skb, 1);
 274         *dptr++ = AX25_P_ROSE;
 275
 276         if (neigh->restarted) {
 277                 if (!rose_send_frame(skb, neigh))
 278                         kfree_skb(skb);
 279         } else {
 280                 skb_queue_tail(&neigh->queue, skb);
 281
 282                 if (!rose_t0timer_running(neigh)) {
 283                         rose_transmit_restart_request(neigh);
 284                         neigh->dce_mode = 0;
 285                         rose_start_t0timer(neigh);
 286                 }
 287         }
 288 }