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                 netdev_err(dev, "out of memory\n");
  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, X25_IFACE_CONNECT);
  53 }
  54
  55
  56
  57 static void x25_disconnected(struct net_device *dev, int reason)
  58 {
  59         x25_connect_disconnect(dev, reason, X25_IFACE_DISCONNECT);
  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 = X25_IFACE_DATA;
  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 X25_IFACE_DATA:    /* 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 X25_IFACE_CONNECT:
 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                                 netdev_err(dev, "LAPB connect request failed, error code = %i\n",
 110                                            result);
 111                 }
 112                 break;
 113
 114         case X25_IFACE_DISCONNECT:
 115                 if ((result = lapb_disconnect_request(dev)) != LAPB_OK) {
 116                         if (result == LAPB_NOTCONNECTED)
 117                                 /* Send disconnect confirm. msg to level 3 */
 118                                 x25_disconnected(dev, 0);
 119                         else
 120                                 netdev_err(dev, "LAPB disconnect request failed, error code = %i\n",
 121                                            result);
 122                 }
 123                 break;
 124
 125         default:                /* to be defined */
 126                 break;
 127         }
 128
 129         dev_kfree_skb(skb);
 130         return NETDEV_TX_OK;
 131 }
 132
 133
 134
 135 static int x25_open(struct net_device *dev)
 136 {
 137         int result;
 138         static const struct lapb_register_struct cb = {
 139                 .connect_confirmation = x25_connected,
 140                 .connect_indication = x25_connected,
 141                 .disconnect_confirmation = x25_disconnected,
 142                 .disconnect_indication = x25_disconnected,
 143                 .data_indication = x25_data_indication,
 144                 .data_transmit = x25_data_transmit,
 145         };
 146
 147         result = lapb_register(dev, &cb);
 148         if (result != LAPB_OK)
 149                 return result;
 150         return 0;
 151 }
 152
 153
 154
 155 static void x25_close(struct net_device *dev)
 156 {
 157         lapb_unregister(dev);
 158 }
 159
 160
 161
 162 static int x25_rx(struct sk_buff *skb)
 163 {
 164         struct net_device *dev = skb->dev;
 165
 166         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {
 167                 dev->stats.rx_dropped++;
 168                 return NET_RX_DROP;
 169         }
 170
 171         if (lapb_data_received(dev, skb) == LAPB_OK)
 172                 return NET_RX_SUCCESS;
 173
 174         dev->stats.rx_errors++;
 175         dev_kfree_skb_any(skb);
 176         return NET_RX_DROP;
 177 }
 178
 179
 180 static struct hdlc_proto proto = {
 181         .open           = x25_open,
 182         .close          = x25_close,
 183         .ioctl          = x25_ioctl,
 184         .netif_rx       = x25_rx,
 185         .xmit           = x25_xmit,
 186         .module         = THIS_MODULE,
 187 };
 188
 189
 190 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 191 {
 192         hdlc_device *hdlc = dev_to_hdlc(dev);
 193         int result;
 194
 195         switch (ifr->ifr_settings.type) {
 196         case IF_GET_PROTO:
 197                 if (dev_to_hdlc(dev)->proto != &proto)
 198                         return -EINVAL;
 199                 ifr->ifr_settings.type = IF_PROTO_X25;
 200                 return 0; /* return protocol only, no settable parameters */
 201
 202         case IF_PROTO_X25:
 203                 if (!capable(CAP_NET_ADMIN))
 204                         return -EPERM;
 205
 206                 if (dev->flags & IFF_UP)
 207                         return -EBUSY;
 208
 209                 result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 210                 if (result)
 211                         return result;
 212
 213                 if ((result = attach_hdlc_protocol(dev, &proto, 0)))
 214                         return result;
 215                 dev->type = ARPHRD_X25;
 216                 call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 217                 netif_dormant_off(dev);
 218                 return 0;
 219         }
 220
 221         return -EINVAL;
 222 }
 223
 224
 225 static int __init mod_init(void)
 226 {
 227         register_hdlc_protocol(&proto);
 228         return 0;
 229 }
 230
 231
 232
 233 static void __exit mod_exit(void)
 234 {
 235         unregister_hdlc_protocol(&proto);
 236 }
 237
 238
 239 module_init(mod_init);
 240 module_exit(mod_exit);
 241
 242 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
 243 MODULE_DESCRIPTION("X.25 protocol support for generic HDLC");
 244 MODULE_LICENSE("GPL v2");