net/rose/rose_link.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/types.h>
   8 #include <linux/socket.h>
   9 #include <linux/in.h>
  10 #include <linux/kernel.h>
  11 #include <linux/jiffies.h>
  12 #include <linux/timer.h>
  13 #include <linux/string.h>
  14 #include <linux/sockios.h>
  15 #include <linux/net.h>
  16 #include <linux/slab.h>
  17 #include <net/ax25.h>
  18 #include <linux/inet.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/skbuff.h>
  21 #include <net/sock.h>
  22 #include <linux/fcntl.h>
  23 #include <linux/mm.h>
  24 #include <linux/interrupt.h>
  25 #include <net/rose.h>
  26
  27 static void rose_ftimer_expiry(struct timer_list *);
  28 static void rose_t0timer_expiry(struct timer_list *);
  29
  30 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
  31 static void rose_transmit_restart_request(struct rose_neigh *neigh);
  32
  33 void rose_start_ftimer(struct rose_neigh *neigh)
  34 {
  35         del_timer(&neigh->ftimer);
  36
  37         neigh->ftimer.function = rose_ftimer_expiry;
  38         neigh->ftimer.expires  =
  39                 jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
  40
  41         add_timer(&neigh->ftimer);
  42 }
  43
  44 static void rose_start_t0timer(struct rose_neigh *neigh)
  45 {
  46         del_timer(&neigh->t0timer);
  47
  48         neigh->t0timer.function = rose_t0timer_expiry;
  49         neigh->t0timer.expires  =
  50                 jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
  51
  52         add_timer(&neigh->t0timer);
  53 }
  54
  55 void rose_stop_ftimer(struct rose_neigh *neigh)
  56 {
  57         del_timer(&neigh->ftimer);
  58 }
  59
  60 void rose_stop_t0timer(struct rose_neigh *neigh)
  61 {
  62         del_timer(&neigh->t0timer);
  63 }
  64
  65 int rose_ftimer_running(struct rose_neigh *neigh)
  66 {
  67         return timer_pending(&neigh->ftimer);
  68 }
  69
  70 static int rose_t0timer_running(struct rose_neigh *neigh)
  71 {
  72         return timer_pending(&neigh->t0timer);
  73 }
  74
  75 static void rose_ftimer_expiry(struct timer_list *t)
  76 {
  77 }
  78
  79 static void rose_t0timer_expiry(struct timer_list *t)
  80 {
  81         struct rose_neigh *neigh = from_timer(neigh, t, t0timer);
  82
  83         rose_transmit_restart_request(neigh);
  84
  85         neigh->dce_mode = 0;
  86
  87         rose_start_t0timer(neigh);
  88 }
  89
  90 /*
  91  *      Interface to ax25_send_frame. Changes my level 2 callsign depending
  92  *      on whether we have a global ROSE callsign or use the default port
  93  *      callsign.
  94  */
  95 static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
  96 {
  97         const ax25_address *rose_call;
  98         ax25_cb *ax25s;
  99
 100         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 101                 rose_call = (const ax25_address *)neigh->dev->dev_addr;
 102         else
 103                 rose_call = &rose_callsign;
 104
 105         ax25s = neigh->ax25;
 106         neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 107         if (ax25s)
 108                 ax25_cb_put(ax25s);
 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         const ax25_address *rose_call;
 121         ax25_cb *ax25s;
 122
 123         if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
 124                 rose_call = (const ax25_address *)neigh->dev->dev_addr;
 125         else
 126                 rose_call = &rose_callsign;
 127
 128         ax25s = neigh->ax25;
 129         neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
 130         if (ax25s)
 131                 ax25_cb_put(ax25s);
 132
 133         return neigh->ax25 != NULL;
 134 }
 135
 136 /*
 137  *      This handles all restart and diagnostic frames.
 138  */
 139 void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
 140 {
 141         struct sk_buff *skbn;
 142
 143         switch (frametype) {
 144         case ROSE_RESTART_REQUEST:
 145                 rose_stop_t0timer(neigh);
 146                 neigh->restarted = 1;
 147                 neigh->dce_mode  = (skb->data[3] == ROSE_DTE_ORIGINATED);
 148                 rose_transmit_restart_confirmation(neigh);
 149                 break;
 150
 151         case ROSE_RESTART_CONFIRMATION:
 152                 rose_stop_t0timer(neigh);
 153                 neigh->restarted = 1;
 154                 break;
 155
 156         case ROSE_DIAGNOSTIC:
 157                 pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
 158                         skb->data + 4);
 159                 break;
 160
 161         default:
 162                 printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
 163                 break;
 164         }
 165
 166         if (neigh->restarted) {
 167                 while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
 168                         if (!rose_send_frame(skbn, neigh))
 169                                 kfree_skb(skbn);
 170         }
 171 }
 172
 173 /*
 174  *      This routine is called when a Restart Request is needed
 175  */
 176 static void rose_transmit_restart_request(struct rose_neigh *neigh)
 177 {
 178         struct sk_buff *skb;
 179         unsigned char *dptr;
 180         int len;
 181
 182         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
 183
 184         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 185                 return;
 186
 187         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 188
 189         dptr = skb_put(skb, ROSE_MIN_LEN + 3);
 190
 191         *dptr++ = AX25_P_ROSE;
 192         *dptr++ = ROSE_GFI;
 193         *dptr++ = 0x00;
 194         *dptr++ = ROSE_RESTART_REQUEST;
 195         *dptr++ = ROSE_DTE_ORIGINATED;
 196         *dptr++ = 0;
 197
 198         if (!rose_send_frame(skb, neigh))
 199                 kfree_skb(skb);
 200 }
 201
 202 /*
 203  * This routine is called when a Restart Confirmation is needed
 204  */
 205 static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
 206 {
 207         struct sk_buff *skb;
 208         unsigned char *dptr;
 209         int len;
 210
 211         len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
 212
 213         if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
 214                 return;
 215
 216         skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
 217
 218         dptr = skb_put(skb, ROSE_MIN_LEN + 1);
 219
 220         *dptr++ = AX25_P_ROSE;
 221         *dptr++ = ROSE_GFI;
 222         *dptr++ = 0x00;
 223         *dptr++ = ROSE_RESTART_CONFIRMATION;
 224
 225         if (!rose_send_frame(skb, neigh))
 226                 kfree_skb(skb);
 227 }
 228
 229 /*
 230  * This routine is called when a Clear Request is needed outside of the context
 231  * of a connected socket.
 232  */
 233 void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
 234 {
 235         struct sk_buff *skb;
 236         unsigned char *dptr;
 237         int len;
 238
 239         if (!neigh->dev)
 240                 return;
 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 }