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