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  =
  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
 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         neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 111
 112         return (neigh->ax25 != NULL);
 113 }
 114
 115 /*
 116  *      Interface to ax25_link_up. Changes my level 2 callsign depending
 117  *      on whether we have a global ROSE callsign or use the default port
 118  *      callsign.
 119  */
 120 static int rose_link_up(struct rose_neigh *neigh)
 121 {
 122         ax25_address *rose_call;
 123
 124         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 125                 rose_call = (ax25_address *)neigh->dev->dev_addr;
 126         else
 127                 rose_call = &rose_callsign;
 128
 129         neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 130
 131         return (neigh->ax25 != NULL);
 132 }
 133
 134 /*
 135  *      This handles all restart and diagnostic frames.
 136  */
 137 void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
 138 {
 139         struct sk_buff *skbn;
 140
 141         switch (frametype) {
 142         case ROSE_RESTART_REQUEST:
 143                 rose_stop_t0timer(neigh);
 144                 neigh->restarted = 1;
 145                 neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
 146                 rose_transmit_restart_confirmation(neigh);
 147                 break;
 148
 149         case ROSE_RESTART_CONFIRMATION:
 150                 rose_stop_t0timer(neigh);
 151                 neigh->restarted = 1;
 152                 break;
 153
 154         case ROSE_DIAGNOSTIC:
 155                 printk(KERN_WARNING "ROSE: received diagnostic #%d - %02X %02X %02X\n", skb->data[3], skb->data[4], skb->data[5], skb->data[6]);
 156                 break;
 157
 158         default:
 159                 printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
 160                 break;
 161         }
 162
 163         if (neigh->restarted) {
 164                 while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
 165                         if (!rose_send_frame(skbn, neigh))
 166                                 kfree_skb(skbn);
 167         }
 168 }
 169
 170 /*
 171  *      This routine is called when a Restart Request is needed
 172  */
 173 static void rose_transmit_restart_request(struct rose_neigh *neigh)
 174 {
 175         struct sk_buff *skb;
 176         unsigned char *dptr;
 177         int len;
 178
 179         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 180
 181         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 182                 return;
 183
 184         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 185
 186         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 187
 188         *dptr++ = AX25_P_ROSE;
 189         *dptr++ = ROSE_GFI;
 190         *dptr++ = 0x00;
 191         *dptr++ = ROSE_RESTART_REQUEST;
 192         *dptr++ = ROSE_DTE_ORIGINATED;
 193         *dptr++ = 0;
 194
 195         if (!rose_send_frame(skb, neigh))
 196                 kfree_skb(skb);
 197 }
 198
 199 /*
 200  * This routine is called when a Restart Confirmation is needed
 201  */
 202 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
 203 {
 204         struct sk_buff *skb;
 205         unsigned char *dptr;
 206         int len;
 207
 208         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
 209
 210         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 211                 return;
 212
 213         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 214
 215         dptr = skb_put(skb, ROSE_MIN_LEN + 1);
 216
 217         *dptr++ = AX25_P_ROSE;
 218         *dptr++ = ROSE_GFI;
 219         *dptr++ = 0x00;
 220         *dptr++ = ROSE_RESTART_CONFIRMATION;
 221
 222         if (!rose_send_frame(skb, neigh))
 223                 kfree_skb(skb);
 224 }
 225
 226 /*
 227  * This routine is called when a Clear Request is needed outside of the context
 228  * of a connected socket.
 229  */
 230 void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
 231 {
 232         struct sk_buff *skb;
 233         unsigned char *dptr;
 234         int len;
 235
 236         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 237
 238         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 239                 return;
 240
 241         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 242
 243         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 244
 245         *dptr++ = AX25_P_ROSE;
 246         *dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
 247         *dptr++ = ((lci >> 0) & 0xFF);
 248         *dptr++ = ROSE_CLEAR_REQUEST;
 249         *dptr++ = cause;
 250         *dptr++ = diagnostic;
 251
 252         if (!rose_send_frame(skb, neigh))
 253                 kfree_skb(skb);
 254 }
 255
 256 void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
 257 {
 258         unsigned char *dptr;
 259
 260 #if 0
 261         if (call_fw_firewall(PF_ROSE, skb->dev, skb->data, NULL, &skb) != FW_ACCEPT) {
 262                 kfree_skb(skb);
 263                 return;
 264         }
 265 #endif
 266
 267         if (neigh->loopback) {
 268                 rose_loopback_queue(skb, neigh);
 269                 return;
 270         }
 271
 272         if (!rose_link_up(neigh))
 273                 neigh->restarted = 0;
 274
 275         dptr = skb_push(skb, 1);
 276         *dptr++ = AX25_P_ROSE;
 277
 278         if (neigh->restarted) {
 279                 if (!rose_send_frame(skb, neigh))
 280                         kfree_skb(skb);
 281         } else {
 282                 skb_queue_tail(&neigh->queue, skb);
 283
 284                 if (!rose_t0timer_running(neigh)) {
 285                         rose_transmit_restart_request(neigh);
 286                         neigh->dce_mode = 0;
 287                         rose_start_t0timer(neigh);
 288                 }
 289         }
 290 }