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 bool up; 27 spinlock_t up_lock; /* Protects "up" */ 28 }; 29 30 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr); 31 32 static struct x25_state *state(hdlc_device *hdlc) 33 { 34 return hdlc->state; 35 } 36 37 /* These functions are callbacks called by LAPB layer */ 38 39 static void x25_connect_disconnect(struct net_device *dev, int reason, int code) 40 { 41 struct sk_buff *skb; 42 unsigned char *ptr; 43 44 if ((skb = dev_alloc_skb(1)) == NULL) { 45 netdev_err(dev, "out of memory\n"); 46 return; 47 } 48 49 ptr = skb_put(skb, 1); 50 *ptr = code; 51 52 skb->protocol = x25_type_trans(skb, dev); 53 netif_rx(skb); 54 } 55 56 57 58 static void x25_connected(struct net_device *dev, int reason) 59 { 60 x25_connect_disconnect(dev, reason, X25_IFACE_CONNECT); 61 } 62 63 64 65 static void x25_disconnected(struct net_device *dev, int reason) 66 { 67 x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT); 68 } 69 70 71 72 static int x25_data_indication(struct net_device *dev, struct sk_buff *skb) 73 { 74 unsigned char *ptr; 75 76 if (skb_cow(skb, 1)) { 77 kfree_skb(skb); 78 return NET_RX_DROP; 79 } 80 81 skb_push(skb, 1); 82 83 ptr = skb->data; 84 *ptr = X25_IFACE_DATA; 85 86 skb->protocol = x25_type_trans(skb, dev); 87 return netif_rx(skb); 88 } 89 90 91 92 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb) 93 { 94 hdlc_device *hdlc = dev_to_hdlc(dev); 95 96 skb_reset_network_header(skb); 97 skb->protocol = hdlc_type_trans(skb, dev); 98 99 if (dev_nit_active(dev)) 100 dev_queue_xmit_nit(skb, dev); 101 102 hdlc->xmit(skb, dev); /* Ignore return value :-( */ 103 } 104 105 106 107 static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev) 108 { 109 hdlc_device *hdlc = dev_to_hdlc(dev); 110 struct x25_state *x25st = state(hdlc); 111 int result; 112 113 /* There should be a pseudo header of 1 byte added by upper layers. 114 * Check to make sure it is there before reading it. 115 */ 116 if (skb->len < 1) { 117 kfree_skb(skb); 118 return NETDEV_TX_OK; 119 } 120 121 spin_lock_bh(&x25st->up_lock); 122 if (!x25st->up) { 123 spin_unlock_bh(&x25st->up_lock); 124 kfree_skb(skb); 125 return NETDEV_TX_OK; 126 } 127 128 switch (skb->data[0]) { 129 case X25_IFACE_DATA: /* Data to be transmitted */ 130 skb_pull(skb, 1); 131 if ((result = lapb_data_request(dev, skb)) != LAPB_OK) 132 dev_kfree_skb(skb); 133 spin_unlock_bh(&x25st->up_lock); 134 return NETDEV_TX_OK; 135 136 case X25_IFACE_CONNECT: 137 if ((result = lapb_connect_request(dev))!= LAPB_OK) { 138 if (result == LAPB_CONNECTED) 139 /* Send connect confirm. msg to level 3 */ 140 x25_connected(dev, 0); 141 else 142 netdev_err(dev, "LAPB connect request failed, error code = %i\n", 143 result); 144 } 145 break; 146 147 case X25_IFACE_DISCONNECT: 148 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) { 149 if (result == LAPB_NOTCONNECTED) 150 /* Send disconnect confirm. msg to level 3 */ 151 x25_disconnected(dev, 0); 152 else 153 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n", 154 result); 155 } 156 break; 157 158 default: /* to be defined */ 159 break; 160 } 161 162 spin_unlock_bh(&x25st->up_lock); 163 dev_kfree_skb(skb); 164 return NETDEV_TX_OK; 165 } 166 167 168 169 static int x25_open(struct net_device *dev) 170 { 171 static const struct lapb_register_struct cb = { 172 .connect_confirmation = x25_connected, 173 .connect_indication = x25_connected, 174 .disconnect_confirmation = x25_disconnected, 175 .disconnect_indication = x25_disconnected, 176 .data_indication = x25_data_indication, 177 .data_transmit = x25_data_transmit, 178 }; 179 hdlc_device *hdlc = dev_to_hdlc(dev); 180 struct x25_state *x25st = state(hdlc); 181 struct lapb_parms_struct params; 182 int result; 183 184 result = lapb_register(dev, &cb); 185 if (result != LAPB_OK) 186 return -ENOMEM; 187 188 result = lapb_getparms(dev, ¶ms); 189 if (result != LAPB_OK) 190 return -EINVAL; 191 192 if (state(hdlc)->settings.dce) 193 params.mode = params.mode | LAPB_DCE; 194 195 if (state(hdlc)->settings.modulo == 128) 196 params.mode = params.mode | LAPB_EXTENDED; 197 198 params.window = state(hdlc)->settings.window; 199 params.t1 = state(hdlc)->settings.t1; 200 params.t2 = state(hdlc)->settings.t2; 201 params.n2 = state(hdlc)->settings.n2; 202 203 result = lapb_setparms(dev, ¶ms); 204 if (result != LAPB_OK) 205 return -EINVAL; 206 207 spin_lock_bh(&x25st->up_lock); 208 x25st->up = true; 209 spin_unlock_bh(&x25st->up_lock); 210 211 return 0; 212 } 213 214 215 216 static void x25_close(struct net_device *dev) 217 { 218 hdlc_device *hdlc = dev_to_hdlc(dev); 219 struct x25_state *x25st = state(hdlc); 220 221 spin_lock_bh(&x25st->up_lock); 222 x25st->up = false; 223 spin_unlock_bh(&x25st->up_lock); 224 225 lapb_unregister(dev); 226 } 227 228 229 230 static int x25_rx(struct sk_buff *skb) 231 { 232 struct net_device *dev = skb->dev; 233 hdlc_device *hdlc = dev_to_hdlc(dev); 234 struct x25_state *x25st = state(hdlc); 235 236 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) { 237 dev->stats.rx_dropped++; 238 return NET_RX_DROP; 239 } 240 241 spin_lock_bh(&x25st->up_lock); 242 if (!x25st->up) { 243 spin_unlock_bh(&x25st->up_lock); 244 kfree_skb(skb); 245 dev->stats.rx_dropped++; 246 return NET_RX_DROP; 247 } 248 249 if (lapb_data_received(dev, skb) == LAPB_OK) { 250 spin_unlock_bh(&x25st->up_lock); 251 return NET_RX_SUCCESS; 252 } 253 254 spin_unlock_bh(&x25st->up_lock); 255 dev->stats.rx_errors++; 256 dev_kfree_skb_any(skb); 257 return NET_RX_DROP; 258 } 259 260 261 static struct hdlc_proto proto = { 262 .open = x25_open, 263 .close = x25_close, 264 .ioctl = x25_ioctl, 265 .netif_rx = x25_rx, 266 .xmit = x25_xmit, 267 .module = THIS_MODULE, 268 }; 269 270 271 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr) 272 { 273 x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25; 274 const size_t size = sizeof(x25_hdlc_proto); 275 hdlc_device *hdlc = dev_to_hdlc(dev); 276 x25_hdlc_proto new_settings; 277 int result; 278 279 switch (ifr->ifr_settings.type) { 280 case IF_GET_PROTO: 281 if (dev_to_hdlc(dev)->proto != &proto) 282 return -EINVAL; 283 ifr->ifr_settings.type = IF_PROTO_X25; 284 if (ifr->ifr_settings.size < size) { 285 ifr->ifr_settings.size = size; /* data size wanted */ 286 return -ENOBUFS; 287 } 288 if (copy_to_user(x25_s, &state(hdlc)->settings, size)) 289 return -EFAULT; 290 return 0; 291 292 case IF_PROTO_X25: 293 if (!capable(CAP_NET_ADMIN)) 294 return -EPERM; 295 296 if (dev->flags & IFF_UP) 297 return -EBUSY; 298 299 /* backward compatibility */ 300 if (ifr->ifr_settings.size == 0) { 301 new_settings.dce = 0; 302 new_settings.modulo = 8; 303 new_settings.window = 7; 304 new_settings.t1 = 3; 305 new_settings.t2 = 1; 306 new_settings.n2 = 10; 307 } 308 else { 309 if (copy_from_user(&new_settings, x25_s, size)) 310 return -EFAULT; 311 312 if ((new_settings.dce != 0 && 313 new_settings.dce != 1) || 314 (new_settings.modulo != 8 && 315 new_settings.modulo != 128) || 316 new_settings.window < 1 || 317 (new_settings.modulo == 8 && 318 new_settings.window > 7) || 319 (new_settings.modulo == 128 && 320 new_settings.window > 127) || 321 new_settings.t1 < 1 || 322 new_settings.t1 > 255 || 323 new_settings.t2 < 1 || 324 new_settings.t2 > 255 || 325 new_settings.n2 < 1 || 326 new_settings.n2 > 255) 327 return -EINVAL; 328 } 329 330 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT); 331 if (result) 332 return result; 333 334 if ((result = attach_hdlc_protocol(dev, &proto, 335 sizeof(struct x25_state)))) 336 return result; 337 338 memcpy(&state(hdlc)->settings, &new_settings, size); 339 state(hdlc)->up = false; 340 spin_lock_init(&state(hdlc)->up_lock); 341 342 /* There's no header_ops so hard_header_len should be 0. */ 343 dev->hard_header_len = 0; 344 /* When transmitting data: 345 * first we'll remove a pseudo header of 1 byte, 346 * then we'll prepend an LAPB header of at most 3 bytes. 347 */ 348 dev->needed_headroom = 3 - 1; 349 350 dev->type = ARPHRD_X25; 351 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev); 352 netif_dormant_off(dev); 353 return 0; 354 } 355 356 return -EINVAL; 357 } 358 359 360 static int __init mod_init(void) 361 { 362 register_hdlc_protocol(&proto); 363 return 0; 364 } 365 366 367 368 static void __exit mod_exit(void) 369 { 370 unregister_hdlc_protocol(&proto); 371 } 372 373 374 module_init(mod_init); 375 module_exit(mod_exit); 376 377 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>"); 378 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC"); 379 MODULE_LICENSE("GPL v2"); 380