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, ¶ms); 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, ¶ms); 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"); 325