net/x25/x25_dev.c

   1 /*
   2  *      X.25 Packet Layer release 002
   3  *
   4  *      This is ALPHA test software. This code may break your machine, randomly fail to work with new
   5  *      releases, misbehave and/or generally screw up. It might even work.
   6  *
   7  *      This code REQUIRES 2.1.15 or higher
   8  *
   9  *      This module:
  10  *              This module is free software; you can redistribute it and/or
  11  *              modify it under the terms of the GNU General Public License
  12  *              as published by the Free Software Foundation; either version
  13  *              2 of the License, or (at your option) any later version.
  14  *
  15  *      History
  16  *      X.25 001        Jonathan Naylor Started coding.
  17  *      2000-09-04      Henner Eisen    Prevent freeing a dangling skb.
  18  */
  19
  20 #include <linux/config.h>
  21 #if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/socket.h>
  25 #include <linux/in.h>
  26 #include <linux/kernel.h>
  27 #include <linux/sched.h>
  28 #include <linux/timer.h>
  29 #include <linux/string.h>
  30 #include <linux/sockios.h>
  31 #include <linux/net.h>
  32 #include <linux/stat.h>
  33 #include <linux/inet.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/skbuff.h>
  36 #include <net/sock.h>
  37 #include <asm/segment.h>
  38 #include <asm/system.h>
  39 #include <asm/uaccess.h>
  40 #include <linux/fcntl.h>
  41 #include <linux/termios.h>      /* For TIOCINQ/OUTQ */
  42 #include <linux/mm.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/notifier.h>
  45 #include <linux/proc_fs.h>
  46 #include <linux/if_arp.h>
  47 #include <net/x25.h>
  48
  49 static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *neigh)
  50 {
  51         struct sock *sk;
  52         unsigned short frametype;
  53         unsigned int lci;
  54
  55         frametype = skb->data[2];
  56         lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
  57
  58         /*
  59          *      LCI of zero is always for us, and its always a link control
  60          *      frame.
  61          */
  62         if (lci == 0) {
  63                 x25_link_control(skb, neigh, frametype);
  64                 return 0;
  65         }
  66
  67         /*
  68          *      Find an existing socket.
  69          */
  70         if ((sk = x25_find_socket(lci, neigh)) != NULL) {
  71                 int queued = 1;
  72
  73                 skb->h.raw = skb->data;
  74                 bh_lock_sock(sk);
  75                 if (!sk->lock.users) {
  76                         queued = x25_process_rx_frame(sk, skb);
  77                 } else {
  78                         sk_add_backlog(sk, skb);
  79                 }
  80                 bh_unlock_sock(sk);
  81                 return queued;
  82         }
  83
  84         /*
  85          *      Is is a Call Request ? if so process it.
  86          */
  87         if (frametype == X25_CALL_REQUEST)
  88                 return x25_rx_call_request(skb, neigh, lci);
  89
  90         /*
  91          *      Its not a Call Request, nor is it a control frame.
  92          *      Let caller throw it away.
  93          */
  94 /*
  95         x25_transmit_clear_request(neigh, lci, 0x0D);
  96 */
  97         printk(KERN_DEBUG "x25_receive_data(): unknown frame type %2x\n",frametype);
  98
  99         return 0;
 100 }
 101
 102 int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
 103 {
 104         struct x25_neigh *neigh;
 105         int queued;
 106
 107         skb->sk = NULL;
 108
 109         /*
 110          *      Packet received from unrecognised device, throw it away.
 111          */
 112         if ((neigh = x25_get_neigh(dev)) == NULL) {
 113                 printk(KERN_DEBUG "X.25: unknown neighbour - %s\n", dev->name);
 114                 kfree_skb(skb);
 115                 return 0;
 116         }
 117
 118         switch (skb->data[0]) {
 119                 case 0x00:
 120                         skb_pull(skb, 1);
 121                         queued = x25_receive_data(skb, neigh);
 122                         if( ! queued )
 123                                 /* We need to free the skb ourselves because
 124                                  * net_bh() won't care about our return code.
 125                                  */
 126                                 kfree_skb(skb);
 127                         return 0;
 128
 129                 case 0x01:
 130                         x25_link_established(neigh);
 131                         kfree_skb(skb);
 132                         return 0;
 133
 134                 case 0x02:
 135                         x25_link_terminated(neigh);
 136                         kfree_skb(skb);
 137                         return 0;
 138
 139                 case 0x03:
 140                         kfree_skb(skb);
 141                         return 0;
 142
 143                 default:
 144                         kfree_skb(skb);
 145                         return 0;
 146         }
 147 }
 148
 149 int x25_llc_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
 150 {
 151         struct x25_neigh *neigh;
 152
 153         skb->sk = NULL;
 154
 155         /*
 156          *      Packet received from unrecognised device, throw it away.
 157          */
 158         if ((neigh = x25_get_neigh(dev)) == NULL) {
 159                 printk(KERN_DEBUG "X.25: unknown_neighbour - %s\n", dev->name);
 160                 kfree_skb(skb);
 161                 return 0;
 162         }
 163
 164         return x25_receive_data(skb, neigh);
 165 }
 166
 167 void x25_establish_link(struct x25_neigh *neigh)
 168 {
 169         struct sk_buff *skb;
 170         unsigned char *ptr;
 171
 172         switch (neigh->dev->type) {
 173                 case ARPHRD_X25:
 174                         if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
 175                                 printk(KERN_ERR "x25_dev: out of memory\n");
 176                                 return;
 177                         }
 178                         ptr  = skb_put(skb, 1);
 179                         *ptr = 0x01;
 180                         break;
 181
 182 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
 183                 case ARPHRD_ETHER:
 184                         return;
 185 #endif
 186                 default:
 187                         return;
 188         }
 189
 190         skb->protocol = htons(ETH_P_X25);
 191         skb->dev      = neigh->dev;
 192
 193         dev_queue_xmit(skb);
 194 }
 195
 196 void x25_terminate_link(struct x25_neigh *neigh)
 197 {
 198         struct sk_buff *skb;
 199         unsigned char *ptr;
 200
 201         switch (neigh->dev->type) {
 202                 case ARPHRD_X25:
 203                         if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) {
 204                                 printk(KERN_ERR "x25_dev: out of memory\n");
 205                                 return;
 206                         }
 207                         ptr  = skb_put(skb, 1);
 208                         *ptr = 0x02;
 209                         break;
 210
 211 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
 212                 case ARPHRD_ETHER:
 213                         return;
 214 #endif
 215                 default:
 216                         return;
 217         }
 218
 219         skb->protocol = htons(ETH_P_X25);
 220         skb->dev      = neigh->dev;
 221
 222         dev_queue_xmit(skb);
 223 }
 224
 225 void x25_send_frame(struct sk_buff *skb, struct x25_neigh *neigh)
 226 {
 227         unsigned char *dptr;
 228
 229         skb->nh.raw = skb->data;
 230
 231         switch (neigh->dev->type) {
 232                 case ARPHRD_X25:
 233                         dptr  = skb_push(skb, 1);
 234                         *dptr = 0x00;
 235                         break;
 236
 237 #if defined(CONFIG_LLC) || defined(CONFIG_LLC_MODULE)
 238                 case ARPHRD_ETHER:
 239                         kfree_skb(skb);
 240                         return;
 241 #endif
 242                 default:
 243                         kfree_skb(skb);
 244                         return;
 245         }
 246
 247         skb->protocol = htons(ETH_P_X25);
 248         skb->dev      = neigh->dev;
 249
 250         dev_queue_xmit(skb);
 251 }
 252
 253 #endif
 254
 255
 256