drivers/net/wan/hdlc_x25.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Generic HDLC support routines for Linux
   4  * X.25 support
   5  *
   6  * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
   7  */
   8
   9 #include <linux/errno.h>
  10 #include <linux/gfp.h>
  11 #include <linux/hdlc.h>
  12 #include <linux/if_arp.h>
  13 #include <linux/inetdevice.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/lapb.h>
  17 #include <linux/module.h>
  18 #include <linux/pkt_sched.h>
  19 #include <linux/poll.h>
  20 #include <linux/rtnetlink.h>
  21 #include <linux/skbuff.h>
  22 #include <net/x25device.h>
  23
  24 struct x25_state {
  25         x25_hdlc_proto settings;
  26 };
  27
  28 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
  29
  30 static struct x25_state *state(hdlc_device *hdlc)
  31 {
  32         return hdlc->state;
  33 }
  34
  35 /* These functions are callbacks called by LAPB layer */
  36
  37 static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
  38 {
  39         struct sk_buff *skb;
  40         unsigned char *ptr;
  41
  42         if ((skb = dev_alloc_skb(1)) == NULL) {
  43                 netdev_err(dev, "out of memory\n");
  44                 return;
  45         }
  46
  47         ptr = skb_put(skb, 1);
  48         *ptr = code;
  49
  50         skb->protocol = x25_type_trans(skb, dev);
  51         netif_rx(skb);
  52 }
  53
  54
  55
  56 static void x25_connected(struct net_device *dev, int reason)
  57 {
  58         x25_connect_disconnect(dev, reason, X25_IFACE_CONNECT);
  59 }
  60
  61
  62
  63 static void x25_disconnected(struct net_device *dev, int reason)
  64 {
  65         x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
  66 }
  67
  68
  69
  70 static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
  71 {
  72         unsigned char *ptr;
  73
  74         if (skb_cow(skb, 1)) {
  75                 kfree_skb(skb);
  76                 return NET_RX_DROP;
  77         }
  78
  79         skb_push(skb, 1);
  80         skb_reset_network_header(skb);
  81
  82         ptr  = skb->data;
  83         *ptr = X25_IFACE_DATA;
  84
  85         skb->protocol = x25_type_trans(skb, dev);
  86         return netif_rx(skb);
  87 }
  88
  89
  90
  91 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
  92 {
  93         hdlc_device *hdlc = dev_to_hdlc(dev);
  94
  95         skb_reset_network_header(skb);
  96         skb->protocol = hdlc_type_trans(skb, dev);
  97
  98         if (dev_nit_active(dev))
  99                 dev_queue_xmit_nit(skb, dev);
 100
 101         hdlc->xmit(skb, dev); /* Ignore return value :-( */
 102 }
 103
 104
 105
 106 static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
 107 {
 108         int result;
 109
 110         /* There should be a pseudo header of 1 byte added by upper layers.
 111          * Check to make sure it is there before reading it.
 112          */
 113         if (skb->len < 1) {
 114                 kfree_skb(skb);
 115                 return NETDEV_TX_OK;
 116         }
 117
 118         switch (skb->data[0]) {
 119         case X25_IFACE_DATA:    /* Data to be transmitted */
 120                 skb_pull(skb, 1);
 121                 skb_reset_network_header(skb);
 122                 if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 123                         dev_kfree_skb(skb);
 124                 return NETDEV_TX_OK;
 125
 126         case X25_IFACE_CONNECT:
 127                 if ((result = lapb_connect_request(dev))!= LAPB_OK) {
 128                         if (result == LAPB_CONNECTED)
 129                                 /* Send connect confirm. msg to level 3 */
 130                                 x25_connected(dev, 0);
 131                         else
 132                                 netdev_err(dev, "LAPB connect request failed, error code = %i\n",
 133                                            result);
 134                 }
 135                 break;
 136
 137         case X25_IFACE_DISCONNECT:
 138                 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
 139                         if (result == LAPB_NOTCONNECTED)
 140                                 /* Send disconnect confirm. msg to level 3 */
 141                                 x25_disconnected(dev, 0);
 142                         else
 143                                 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
 144                                            result);
 145                 }
 146                 break;
 147
 148         default:                /* to be defined */
 149                 break;
 150         }
 151
 152         dev_kfree_skb(skb);
 153         return NETDEV_TX_OK;
 154 }
 155
 156
 157
 158 static int x25_open(struct net_device *dev)
 159 {
 160         static const struct lapb_register_struct cb = {
 161                 .connect_confirmation = x25_connected,
 162                 .connect_indication = x25_connected,
 163                 .disconnect_confirmation = x25_disconnected,
 164                 .disconnect_indication = x25_disconnected,
 165                 .data_indication = x25_data_indication,
 166                 .data_transmit = x25_data_transmit,
 167         };
 168         hdlc_device *hdlc = dev_to_hdlc(dev);
 169         struct lapb_parms_struct params;
 170         int result;
 171
 172         result = lapb_register(dev, &cb);
 173         if (result != LAPB_OK)
 174                 return result;
 175
 176         result = lapb_getparms(dev, &params);
 177         if (result != LAPB_OK)
 178                 return result;
 179
 180         if (state(hdlc)->settings.dce)
 181                 params.mode = params.mode | LAPB_DCE;
 182
 183         if (state(hdlc)->settings.modulo == 128)
 184                 params.mode = params.mode | LAPB_EXTENDED;
 185
 186         params.window = state(hdlc)->settings.window;
 187         params.t1 = state(hdlc)->settings.t1;
 188         params.t2 = state(hdlc)->settings.t2;
 189         params.n2 = state(hdlc)->settings.n2;
 190
 191         result = lapb_setparms(dev, &params);
 192         if (result != LAPB_OK)
 193                 return result;
 194
 195         return 0;
 196 }
 197
 198
 199
 200 static void x25_close(struct net_device *dev)
 201 {
 202         lapb_unregister(dev);
 203 }
 204
 205
 206
 207 static int x25_rx(struct sk_buff *skb)
 208 {
 209         struct net_device *dev = skb->dev;
 210
 211         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 212                 dev->stats.rx_dropped++;
 213                 return NET_RX_DROP;
 214         }
 215
 216         if (lapb_data_received(dev, skb) == LAPB_OK)
 217                 return NET_RX_SUCCESS;
 218
 219         dev->stats.rx_errors++;
 220         dev_kfree_skb_any(skb);
 221         return NET_RX_DROP;
 222 }
 223
 224
 225 static struct hdlc_proto proto = {
 226         .open           = x25_open,
 227         .close          = x25_close,
 228         .ioctl          = x25_ioctl,
 229         .netif_rx       = x25_rx,
 230         .xmit           = x25_xmit,
 231         .module         = THIS_MODULE,
 232 };
 233
 234
 235 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 236 {
 237         x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
 238         const size_t size = sizeof(x25_hdlc_proto);
 239         hdlc_device *hdlc = dev_to_hdlc(dev);
 240         x25_hdlc_proto new_settings;
 241         int result;
 242
 243         switch (ifr->ifr_settings.type) {
 244         case IF_GET_PROTO:
 245                 if (dev_to_hdlc(dev)->proto != &proto)
 246                         return -EINVAL;
 247                 ifr->ifr_settings.type = IF_PROTO_X25;
 248                 if (ifr->ifr_settings.size < size) {
 249                         ifr->ifr_settings.size = size; /* data size wanted */
 250                         return -ENOBUFS;
 251                 }
 252                 if (copy_to_user(x25_s, &state(hdlc)->settings, size))
 253                         return -EFAULT;
 254                 return 0;
 255
 256         case IF_PROTO_X25:
 257                 if (!capable(CAP_NET_ADMIN))
 258                         return -EPERM;
 259
 260                 if (dev->flags & IFF_UP)
 261                         return -EBUSY;
 262
 263                 /* backward compatibility */
 264                 if (ifr->ifr_settings.size == 0) {
 265                         new_settings.dce = 0;
 266                         new_settings.modulo = 8;
 267                         new_settings.window = 7;
 268                         new_settings.t1 = 3;
 269                         new_settings.t2 = 1;
 270                         new_settings.n2 = 10;
 271                 }
 272                 else {
 273                         if (copy_from_user(&new_settings, x25_s, size))
 274                                 return -EFAULT;
 275
 276                         if ((new_settings.dce != 0 &&
 277                         new_settings.dce != 1) ||
 278                         (new_settings.modulo != 8 &&
 279                         new_settings.modulo != 128) ||
 280                         new_settings.window < 1 ||
 281                         (new_settings.modulo == 8 &&
 282                         new_settings.window > 7) ||
 283                         (new_settings.modulo == 128 &&
 284                         new_settings.window > 127) ||
 285                         new_settings.t1 < 1 ||
 286                         new_settings.t1 > 255 ||
 287                         new_settings.t2 < 1 ||
 288                         new_settings.t2 > 255 ||
 289                         new_settings.n2 < 1 ||
 290                         new_settings.n2 > 255)
 291                                 return -EINVAL;
 292                 }
 293
 294                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 295                 if (result)
 296                         return result;
 297
 298                 if ((result = attach_hdlc_protocol(dev, &proto,
 299                                                    sizeof(struct x25_state))))
 300                         return result;
 301
 302                 memcpy(&state(hdlc)->settings, &new_settings, size);
 303
 304                 /* There's no header_ops so hard_header_len should be 0. */
 305                 dev->hard_header_len = 0;
 306                 /* When transmitting data:
 307                  * first we'll remove a pseudo header of 1 byte,
 308                  * then we'll prepend an LAPB header of at most 3 bytes.
 309                  */
 310                 dev->needed_headroom = 3 - 1;
 311
 312                 dev->type = ARPHRD_X25;
 313                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 314                 netif_dormant_off(dev);
 315                 return 0;
 316         }
 317
 318         return -EINVAL;
 319 }
 320
 321
 322 static int __init mod_init(void)
 323 {
 324         register_hdlc_protocol(&proto);
 325         return 0;
 326 }
 327
 328
 329
 330 static void __exit mod_exit(void)
 331 {
 332         unregister_hdlc_protocol(&proto);
 333 }
 334
 335
 336 module_init(mod_init);
 337 module_exit(mod_exit);
 338
 339 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 340 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
 341 MODULE_LICENSE("GPL v2");