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
 111         /* X.25 to LAPB */
 112         switch (skb->data[0]) {
 113         case X25_IFACE_DATA:    /* Data to be transmitted */
 114                 skb_pull(skb, 1);
 115                 skb_reset_network_header(skb);
 116                 if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 117                         dev_kfree_skb(skb);
 118                 return NETDEV_TX_OK;
 119
 120         case X25_IFACE_CONNECT:
 121                 if ((result = lapb_connect_request(dev))!= LAPB_OK) {
 122                         if (result == LAPB_CONNECTED)
 123                                 /* Send connect confirm. msg to level 3 */
 124                                 x25_connected(dev, 0);
 125                         else
 126                                 netdev_err(dev, "LAPB connect request failed, error code = %i\n",
 127                                            result);
 128                 }
 129                 break;
 130
 131         case X25_IFACE_DISCONNECT:
 132                 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
 133                         if (result == LAPB_NOTCONNECTED)
 134                                 /* Send disconnect confirm. msg to level 3 */
 135                                 x25_disconnected(dev, 0);
 136                         else
 137                                 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
 138                                            result);
 139                 }
 140                 break;
 141
 142         default:                /* to be defined */
 143                 break;
 144         }
 145
 146         dev_kfree_skb(skb);
 147         return NETDEV_TX_OK;
 148 }
 149
 150
 151
 152 static int x25_open(struct net_device *dev)
 153 {
 154         static const struct lapb_register_struct cb = {
 155                 .connect_confirmation = x25_connected,
 156                 .connect_indication = x25_connected,
 157                 .disconnect_confirmation = x25_disconnected,
 158                 .disconnect_indication = x25_disconnected,
 159                 .data_indication = x25_data_indication,
 160                 .data_transmit = x25_data_transmit,
 161         };
 162         hdlc_device *hdlc = dev_to_hdlc(dev);
 163         struct lapb_parms_struct params;
 164         int result;
 165
 166         result = lapb_register(dev, &cb);
 167         if (result != LAPB_OK)
 168                 return result;
 169
 170         result = lapb_getparms(dev, &params);
 171         if (result != LAPB_OK)
 172                 return result;
 173
 174         if (state(hdlc)->settings.dce)
 175                 params.mode = params.mode | LAPB_DCE;
 176
 177         if (state(hdlc)->settings.modulo == 128)
 178                 params.mode = params.mode | LAPB_EXTENDED;
 179
 180         params.window = state(hdlc)->settings.window;
 181         params.t1 = state(hdlc)->settings.t1;
 182         params.t2 = state(hdlc)->settings.t2;
 183         params.n2 = state(hdlc)->settings.n2;
 184
 185         result = lapb_setparms(dev, &params);
 186         if (result != LAPB_OK)
 187                 return result;
 188
 189         return 0;
 190 }
 191
 192
 193
 194 static void x25_close(struct net_device *dev)
 195 {
 196         lapb_unregister(dev);
 197 }
 198
 199
 200
 201 static int x25_rx(struct sk_buff *skb)
 202 {
 203         struct net_device *dev = skb->dev;
 204
 205         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 206                 dev->stats.rx_dropped++;
 207                 return NET_RX_DROP;
 208         }
 209
 210         if (lapb_data_received(dev, skb) == LAPB_OK)
 211                 return NET_RX_SUCCESS;
 212
 213         dev->stats.rx_errors++;
 214         dev_kfree_skb_any(skb);
 215         return NET_RX_DROP;
 216 }
 217
 218
 219 static struct hdlc_proto proto = {
 220         .open           = x25_open,
 221         .close          = x25_close,
 222         .ioctl          = x25_ioctl,
 223         .netif_rx       = x25_rx,
 224         .xmit           = x25_xmit,
 225         .module         = THIS_MODULE,
 226 };
 227
 228
 229 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 230 {
 231         x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
 232         const size_t size = sizeof(x25_hdlc_proto);
 233         hdlc_device *hdlc = dev_to_hdlc(dev);
 234         x25_hdlc_proto new_settings;
 235         int result;
 236
 237         switch (ifr->ifr_settings.type) {
 238         case IF_GET_PROTO:
 239                 if (dev_to_hdlc(dev)->proto != &proto)
 240                         return -EINVAL;
 241                 ifr->ifr_settings.type = IF_PROTO_X25;
 242                 if (ifr->ifr_settings.size < size) {
 243                         ifr->ifr_settings.size = size; /* data size wanted */
 244                         return -ENOBUFS;
 245                 }
 246                 if (copy_to_user(x25_s, &state(hdlc)->settings, size))
 247                         return -EFAULT;
 248                 return 0;
 249
 250         case IF_PROTO_X25:
 251                 if (!capable(CAP_NET_ADMIN))
 252                         return -EPERM;
 253
 254                 if (dev->flags & IFF_UP)
 255                         return -EBUSY;
 256
 257                 /* backward compatibility */
 258                 if (ifr->ifr_settings.size == 0) {
 259                         new_settings.dce = 0;
 260                         new_settings.modulo = 8;
 261                         new_settings.window = 7;
 262                         new_settings.t1 = 3;
 263                         new_settings.t2 = 1;
 264                         new_settings.n2 = 10;
 265                 }
 266                 else {
 267                         if (copy_from_user(&new_settings, x25_s, size))
 268                                 return -EFAULT;
 269
 270                         if ((new_settings.dce != 0 &&
 271                         new_settings.dce != 1) ||
 272                         (new_settings.modulo != 8 &&
 273                         new_settings.modulo != 128) ||
 274                         new_settings.window < 1 ||
 275                         (new_settings.modulo == 8 &&
 276                         new_settings.window > 7) ||
 277                         (new_settings.modulo == 128 &&
 278                         new_settings.window > 127) ||
 279                         new_settings.t1 < 1 ||
 280                         new_settings.t1 > 255 ||
 281                         new_settings.t2 < 1 ||
 282                         new_settings.t2 > 255 ||
 283                         new_settings.n2 < 1 ||
 284                         new_settings.n2 > 255)
 285                                 return -EINVAL;
 286                 }
 287
 288                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 289                 if (result)
 290                         return result;
 291
 292                 if ((result = attach_hdlc_protocol(dev, &proto,
 293                                                    sizeof(struct x25_state))))
 294                         return result;
 295
 296                 memcpy(&state(hdlc)->settings, &new_settings, size);
 297                 dev->type = ARPHRD_X25;
 298                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 299                 netif_dormant_off(dev);
 300                 return 0;
 301         }
 302
 303         return -EINVAL;
 304 }
 305
 306
 307 static int __init mod_init(void)
 308 {
 309         register_hdlc_protocol(&proto);
 310         return 0;
 311 }
 312
 313
 314
 315 static void __exit mod_exit(void)
 316 {
 317         unregister_hdlc_protocol(&proto);
 318 }
 319
 320
 321 module_init(mod_init);
 322 module_exit(mod_exit);
 323
 324 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 325 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
 326 MODULE_LICENSE("GPL v2");