net/802/p8022.c

   1 /*
   2  *      NET3:   Support for 802.2 demultiplexing off Ethernet
   3  *              This program is free software; you can redistribute it and/or
   4  *              modify it under the terms of the GNU General Public License
   5  *              as published by the Free Software Foundation; either version
   6  *              2 of the License, or (at your option) any later version.
   7  *
   8  *              Demultiplex 802.2 encoded protocols. We match the entry by the
   9  *              SSAP/DSAP pair and then deliver to the registered datalink that
  10  *              matches. The control byte is ignored and handling of such items
  11  *              is up to the routine passed the frame.
  12  *
  13  *              Unlike the 802.3 datalink we have a list of 802.2 entries as
  14  *              there are multiple protocols to demux. The list is currently
  15  *              short (3 or 4 entries at most). The current demux assumes this.
  16  */
  17 #include <linux/module.h>
  18 #include <linux/netdevice.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/slab.h>
  21 #include <net/datalink.h>
  22 #include <linux/mm.h>
  23 #include <linux/in.h>
  24 #include <linux/init.h>
  25 #include <net/llc.h>
  26 #include <net/p8022.h>
  27
  28 static int p8022_request(struct datalink_proto *dl, struct sk_buff *skb,
  29                          unsigned char *dest)
  30 {
  31         llc_build_and_send_ui_pkt(dl->sap, skb, dest, dl->sap->laddr.lsap);
  32         return 0;
  33 }
  34
  35 struct datalink_proto *register_8022_client(unsigned char type,
  36                                             int (*func)(struct sk_buff *skb,
  37                                                         struct net_device *dev,
  38                                                         struct packet_type *pt,
  39                                                         struct net_device *orig_dev))
  40 {
  41         struct datalink_proto *proto;
  42
  43         proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
  44         if (proto) {
  45                 proto->type[0]          = type;
  46                 proto->header_length    = 3;
  47                 proto->request          = p8022_request;
  48                 proto->sap = llc_sap_open(type, func);
  49                 if (!proto->sap) {
  50                         kfree(proto);
  51                         proto = NULL;
  52                 }
  53         }
  54         return proto;
  55 }
  56
  57 void unregister_8022_client(struct datalink_proto *proto)
  58 {
  59         llc_sap_put(proto->sap);
  60         kfree(proto);
  61 }
  62
  63 EXPORT_SYMBOL(register_8022_client);
  64 EXPORT_SYMBOL(unregister_8022_client);
  65
  66 MODULE_LICENSE("GPL");