net/802/p8022.c

   1 /*
   2  *      NET3:   Support for 802.2 demultiplexing off Ethernet (Token ring
   3  *              is kept separate see p8022tr.c)
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  *              Demultiplex 802.2 encoded protocols. We match the entry by the
  10  *              SSAP/DSAP pair and then deliver to the registered datalink that
  11  *              matches. The control byte is ignored and handling of such items
  12  *              is up to the routine passed the frame.
  13  *
  14  *              Unlike the 802.3 datalink we have a list of 802.2 entries as
  15  *              there are multiple protocols to demux. The list is currently
  16  *              short (3 or 4 entries at most). The current demux assumes this.
  17  */
  18 #include <linux/module.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/skbuff.h>
  21 #include <linux/slab.h>
  22 #include <net/datalink.h>
  23 #include <linux/mm.h>
  24 #include <linux/in.h>
  25 #include <linux/init.h>
  26 #include <net/llc.h>
  27 #include <net/p8022.h>
  28
  29 static int p8022_request(struct datalink_proto *dl, struct sk_buff *skb,
  30                          unsigned char *dest)
  31 {
  32         llc_build_and_send_ui_pkt(dl->sap, skb, dest, dl->sap->laddr.lsap);
  33         return 0;
  34 }
  35
  36 struct datalink_proto *register_8022_client(unsigned char type,
  37                                             int (*func)(struct sk_buff *skb,
  38                                                         struct net_device *dev,
  39                                                         struct packet_type *pt,
  40                                                         struct net_device *orig_dev))
  41 {
  42         struct datalink_proto *proto;
  43
  44         proto = kmalloc(sizeof(*proto), GFP_ATOMIC);
  45         if (proto) {
  46                 proto->type[0]          = type;
  47                 proto->header_length    = 3;
  48                 proto->request          = p8022_request;
  49                 proto->sap = llc_sap_open(type, func);
  50                 if (!proto->sap) {
  51                         kfree(proto);
  52                         proto = NULL;
  53                 }
  54         }
  55         return proto;
  56 }
  57
  58 void unregister_8022_client(struct datalink_proto *proto)
  59 {
  60         llc_sap_put(proto->sap);
  61         kfree(proto);
  62 }
  63
  64 EXPORT_SYMBOL(register_8022_client);
  65 EXPORT_SYMBOL(unregister_8022_client);
  66
  67 MODULE_LICENSE("GPL");