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