drivers/net/wan/hdlc_x25.c

   1 /*
   2  * Generic HDLC support routines for Linux
   3  * X.25 support
   4  *
   5  * Copyright (C) 1999 - 2006 Krzysztof Halasa <khc@pm.waw.pl>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of version 2 of the GNU General Public License
   9  * as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/poll.h>
  16 #include <linux/errno.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/init.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/pkt_sched.h>
  21 #include <linux/inetdevice.h>
  22 #include <linux/lapb.h>
  23 #include <linux/rtnetlink.h>
  24 #include <linux/hdlc.h>
  25
  26 #include <net/x25device.h>
  27
  28 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
  29
  30 /* These functions are callbacks called by LAPB layer */
  31
  32 static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
  33 {
  34         struct sk_buff *skb;
  35         unsigned char *ptr;
  36
  37         if ((skb = dev_alloc_skb(1)) == NULL) {
  38                 printk(KERN_ERR "%s: out of memory\n", dev->name);
  39                 return;
  40         }
  41
  42         ptr = skb_put(skb, 1);
  43         *ptr = code;
  44
  45         skb->protocol = x25_type_trans(skb, dev);
  46         netif_rx(skb);
  47 }
  48
  49
  50
  51 static void x25_connected(struct net_device *dev, int reason)
  52 {
  53         x25_connect_disconnect(dev, reason, 1);
  54 }
  55
  56
  57
  58 static void x25_disconnected(struct net_device *dev, int reason)
  59 {
  60         x25_connect_disconnect(dev, reason, 2);
  61 }
  62
  63
  64
  65 static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
  66 {
  67         unsigned char *ptr;
  68
  69         skb_push(skb, 1);
  70
  71         if (skb_cow(skb, 1))
  72                 return NET_RX_DROP;
  73
  74         ptr  = skb->data;
  75         *ptr = 0;
  76
  77         skb->protocol = x25_type_trans(skb, dev);
  78         return netif_rx(skb);
  79 }
  80
  81
  82
  83 static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
  84 {
  85         hdlc_device *hdlc = dev_to_hdlc(dev);
  86         hdlc->xmit(skb, dev); /* Ignore return value :-( */
  87 }
  88
  89
  90
  91 static int x25_xmit(struct sk_buff *skb, struct net_device *dev)
  92 {
  93         int result;
  94
  95
  96         /* X.25 to LAPB */
  97         switch (skb->data[0]) {
  98         case 0:         /* Data to be transmitted */
  99                 skb_pull(skb, 1);
 100                 if ((result = lapb_data_request(dev, skb)) != LAPB_OK)
 101                         dev_kfree_skb(skb);
 102                 return 0;
 103
 104         case 1:
 105                 if ((result = lapb_connect_request(dev))!= LAPB_OK) {
 106                         if (result == LAPB_CONNECTED)
 107                                 /* Send connect confirm. msg to level 3 */
 108                                 x25_connected(dev, 0);
 109                         else
 110                                 printk(KERN_ERR "%s: LAPB connect request "
 111                                        "failed, error code = %i\n",
 112                                        dev->name, result);
 113                 }
 114                 break;
 115
 116         case 2:
 117                 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
 118                         if (result == LAPB_NOTCONNECTED)
 119                                 /* Send disconnect confirm. msg to level 3 */
 120                                 x25_disconnected(dev, 0);
 121                         else
 122                                 printk(KERN_ERR "%s: LAPB disconnect request "
 123                                        "failed, error code = %i\n",
 124                                        dev->name, result);
 125                 }
 126                 break;
 127
 128         default:                /* to be defined */
 129                 break;
 130         }
 131
 132         dev_kfree_skb(skb);
 133         return 0;
 134 }
 135
 136
 137
 138 static int x25_open(struct net_device *dev)
 139 {
 140         struct lapb_register_struct cb;
 141         int result;
 142
 143         cb.connect_confirmation = x25_connected;
 144         cb.connect_indication = x25_connected;
 145         cb.disconnect_confirmation = x25_disconnected;
 146         cb.disconnect_indication = x25_disconnected;
 147         cb.data_indication = x25_data_indication;
 148         cb.data_transmit = x25_data_transmit;
 149
 150         result = lapb_register(dev, &cb);
 151         if (result != LAPB_OK)
 152                 return result;
 153         return 0;
 154 }
 155
 156
 157
 158 static void x25_close(struct net_device *dev)
 159 {
 160         lapb_unregister(dev);
 161 }
 162
 163
 164
 165 static int x25_rx(struct sk_buff *skb)
 166 {
 167         struct hdlc_device_desc *desc = dev_to_desc(skb->dev);
 168
 169         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 170                 desc->stats.rx_dropped++;
 171                 return NET_RX_DROP;
 172         }
 173
 174         if (lapb_data_received(skb->dev, skb) == LAPB_OK)
 175                 return NET_RX_SUCCESS;
 176
 177         desc->stats.rx_errors++;
 178         dev_kfree_skb_any(skb);
 179         return NET_RX_DROP;
 180 }
 181
 182
 183 static struct hdlc_proto proto = {
 184         .open           = x25_open,
 185         .close          = x25_close,
 186         .ioctl          = x25_ioctl,
 187         .module         = THIS_MODULE,
 188 };
 189
 190
 191 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 192 {
 193         hdlc_device *hdlc = dev_to_hdlc(dev);
 194         int result;
 195
 196         switch (ifr->ifr_settings.type) {
 197         case IF_GET_PROTO:
 198                 if (dev_to_hdlc(dev)->proto != &proto)
 199                         return -EINVAL;
 200                 ifr->ifr_settings.type = IF_PROTO_X25;
 201                 return 0; /* return protocol only, no settable parameters */
 202
 203         case IF_PROTO_X25:
 204                 if(!capable(CAP_NET_ADMIN))
 205                         return -EPERM;
 206
 207                 if(dev->flags & IFF_UP)
 208                         return -EBUSY;
 209
 210                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 211                 if (result)
 212                         return result;
 213
 214                 if ((result = attach_hdlc_protocol(dev, &proto,
 215                                                    x25_rx, 0)) != 0)
 216                         return result;
 217                 dev->hard_start_xmit = x25_xmit;
 218                 dev->hard_header = NULL;
 219                 dev->type = ARPHRD_X25;
 220                 dev->addr_len = 0;
 221                 netif_dormant_off(dev);
 222                 return 0;
 223         }
 224
 225         return -EINVAL;
 226 }
 227
 228
 229 static int __init mod_init(void)
 230 {
 231         register_hdlc_protocol(&proto);
 232         return 0;
 233 }
 234
 235
 236
 237 static void __exit mod_exit(void)
 238 {
 239         unregister_hdlc_protocol(&proto);
 240 }
 241
 242
 243 module_init(mod_init);
 244 module_exit(mod_exit);
 245
 246 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 247 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
 248 MODULE_LICENSE("GPL v2");