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                 return NET_RX_DROP;
  76
  77         skb_push(skb, 1);
  78         skb_reset_network_header(skb);
  79
  80         ptr  = skb->data;
  81         *ptr = X25_IFACE_DATA;
  82
  83         skb->protocol = x25_type_trans(skb, dev);
  84         return netif_rx(skb);
  85 }
  86
  87
  88
  89 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
  90 {
  91         hdlc_device *hdlc = dev_to_hdlc(dev);
  92
  93         skb_reset_network_header(skb);
  94         skb->protocol = hdlc_type_trans(skb, dev);
  95
  96         if (dev_nit_active(dev))
  97                 dev_queue_xmit_nit(skb, dev);
  98
  99         hdlc->xmit(skb, dev); /* Ignore return value :-( */
 100 }
 101
 102
 103
 104 static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
 105 {
 106         int result;
 107
 108
 109         /* X.25 to LAPB */
 110         switch (skb->data[0]) {
 111         case X25_IFACE_DATA:    /* Data to be transmitted */
 112                 skb_pull(skb, 1);
 113                 skb_reset_network_header(skb);
 114                 if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 115                         dev_kfree_skb(skb);
 116                 return NETDEV_TX_OK;
 117
 118         case X25_IFACE_CONNECT:
 119                 if ((result = lapb_connect_request(dev))!= LAPB_OK) {
 120                         if (result == LAPB_CONNECTED)
 121                                 /* Send connect confirm. msg to level 3 */
 122                                 x25_connected(dev, 0);
 123                         else
 124                                 netdev_err(dev, "LAPB connect request failed, error code = %i\n",
 125                                            result);
 126                 }
 127                 break;
 128
 129         case X25_IFACE_DISCONNECT:
 130                 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
 131                         if (result == LAPB_NOTCONNECTED)
 132                                 /* Send disconnect confirm. msg to level 3 */
 133                                 x25_disconnected(dev, 0);
 134                         else
 135                                 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
 136                                            result);
 137                 }
 138                 break;
 139
 140         default:                /* to be defined */
 141                 break;
 142         }
 143
 144         dev_kfree_skb(skb);
 145         return NETDEV_TX_OK;
 146 }
 147
 148
 149
 150 static int x25_open(struct net_device *dev)
 151 {
 152         static const struct lapb_register_struct cb = {
 153                 .connect_confirmation = x25_connected,
 154                 .connect_indication = x25_connected,
 155                 .disconnect_confirmation = x25_disconnected,
 156                 .disconnect_indication = x25_disconnected,
 157                 .data_indication = x25_data_indication,
 158                 .data_transmit = x25_data_transmit,
 159         };
 160         hdlc_device *hdlc = dev_to_hdlc(dev);
 161         struct lapb_parms_struct params;
 162         int result;
 163
 164         result = lapb_register(dev, &cb);
 165         if (result != LAPB_OK)
 166                 return result;
 167
 168         result = lapb_getparms(dev, &params);
 169         if (result != LAPB_OK)
 170                 return result;
 171
 172         if (state(hdlc)->settings.dce)
 173                 params.mode = params.mode | LAPB_DCE;
 174
 175         if (state(hdlc)->settings.modulo == 128)
 176                 params.mode = params.mode | LAPB_EXTENDED;
 177
 178         params.window = state(hdlc)->settings.window;
 179         params.t1 = state(hdlc)->settings.t1;
 180         params.t2 = state(hdlc)->settings.t2;
 181         params.n2 = state(hdlc)->settings.n2;
 182
 183         result = lapb_setparms(dev, &params);
 184         if (result != LAPB_OK)
 185                 return result;
 186
 187         return 0;
 188 }
 189
 190
 191
 192 static void x25_close(struct net_device *dev)
 193 {
 194         lapb_unregister(dev);
 195 }
 196
 197
 198
 199 static int x25_rx(struct sk_buff *skb)
 200 {
 201         struct net_device *dev = skb->dev;
 202
 203         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 204                 dev->stats.rx_dropped++;
 205                 return NET_RX_DROP;
 206         }
 207
 208         if (lapb_data_received(dev, skb) == LAPB_OK)
 209                 return NET_RX_SUCCESS;
 210
 211         dev->stats.rx_errors++;
 212         dev_kfree_skb_any(skb);
 213         return NET_RX_DROP;
 214 }
 215
 216
 217 static struct hdlc_proto proto = {
 218         .open           = x25_open,
 219         .close          = x25_close,
 220         .ioctl          = x25_ioctl,
 221         .netif_rx       = x25_rx,
 222         .xmit           = x25_xmit,
 223         .module         = THIS_MODULE,
 224 };
 225
 226
 227 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 228 {
 229         x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
 230         const size_t size = sizeof(x25_hdlc_proto);
 231         hdlc_device *hdlc = dev_to_hdlc(dev);
 232         x25_hdlc_proto new_settings;
 233         int result;
 234
 235         switch (ifr->ifr_settings.type) {
 236         case IF_GET_PROTO:
 237                 if (dev_to_hdlc(dev)->proto != &proto)
 238                         return -EINVAL;
 239                 ifr->ifr_settings.type = IF_PROTO_X25;
 240                 if (ifr->ifr_settings.size < size) {
 241                         ifr->ifr_settings.size = size; /* data size wanted */
 242                         return -ENOBUFS;
 243                 }
 244                 if (copy_to_user(x25_s, &state(hdlc)->settings, size))
 245                         return -EFAULT;
 246                 return 0;
 247
 248         case IF_PROTO_X25:
 249                 if (!capable(CAP_NET_ADMIN))
 250                         return -EPERM;
 251
 252                 if (dev->flags & IFF_UP)
 253                         return -EBUSY;
 254
 255                 /* backward compatibility */
 256                 if (ifr->ifr_settings.size == 0) {
 257                         new_settings.dce = 0;
 258                         new_settings.modulo = 8;
 259                         new_settings.window = 7;
 260                         new_settings.t1 = 3;
 261                         new_settings.t2 = 1;
 262                         new_settings.n2 = 10;
 263                 }
 264                 else {
 265                         if (copy_from_user(&new_settings, x25_s, size))
 266                                 return -EFAULT;
 267
 268                         if ((new_settings.dce != 0 &&
 269                         new_settings.dce != 1) ||
 270                         (new_settings.modulo != 8 &&
 271                         new_settings.modulo != 128) ||
 272                         new_settings.window < 1 ||
 273                         (new_settings.modulo == 8 &&
 274                         new_settings.window > 7) ||
 275                         (new_settings.modulo == 128 &&
 276                         new_settings.window > 127) ||
 277                         new_settings.t1 < 1 ||
 278                         new_settings.t1 > 255 ||
 279                         new_settings.t2 < 1 ||
 280                         new_settings.t2 > 255 ||
 281                         new_settings.n2 < 1 ||
 282                         new_settings.n2 > 255)
 283                                 return -EINVAL;
 284                 }
 285
 286                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 287                 if (result)
 288                         return result;
 289
 290                 if ((result = attach_hdlc_protocol(dev, &proto,
 291                                                    sizeof(struct x25_state))))
 292                         return result;
 293
 294                 memcpy(&state(hdlc)->settings, &new_settings, size);
 295                 dev->type = ARPHRD_X25;
 296                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 297                 netif_dormant_off(dev);
 298                 return 0;
 299         }
 300
 301         return -EINVAL;
 302 }
 303
 304
 305 static int __init mod_init(void)
 306 {
 307         register_hdlc_protocol(&proto);
 308         return 0;
 309 }
 310
 311
 312
 313 static void __exit mod_exit(void)
 314 {
 315         unregister_hdlc_protocol(&proto);
 316 }
 317
 318
 319 module_init(mod_init);
 320 module_exit(mod_exit);
 321
 322 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 323 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
 324 MODULE_LICENSE("GPL v2");