release/src-rt-6.x.4708/linux/linux-2.6.36/net/ipv6/protocol.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              PF_INET6 protocol dispatch tables.
   7  *
   8  * Authors:     Pedro Roque     <roque@di.fc.ul.pt>
   9  *
  10  *              This program 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
  16 /*
  17  *      Changes:
  18  *
  19  *      Vince Laviano (vince@cs.stanford.edu)       16 May 2001
  20  *      - Removed unused variable 'inet6_protocol_base'
  21  *      - Modified inet6_del_protocol() to correctly maintain copy bit.
  22  */
  23 #include <linux/module.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/spinlock.h>
  26 #include <net/protocol.h>
  27
  28 const struct inet6_protocol *inet6_protos[MAX_INET_PROTOS];
  29 static DEFINE_SPINLOCK(inet6_proto_lock);
  30
  31
  32 int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol)
  33 {
  34         int ret, hash = protocol & (MAX_INET_PROTOS - 1);
  35
  36         spin_lock_bh(&inet6_proto_lock);
  37
  38         if (inet6_protos[hash]) {
  39                 ret = -1;
  40         } else {
  41                 inet6_protos[hash] = prot;
  42                 ret = 0;
  43         }
  44
  45         spin_unlock_bh(&inet6_proto_lock);
  46
  47         return ret;
  48 }
  49
  50 EXPORT_SYMBOL(inet6_add_protocol);
  51
  52 /*
  53  *      Remove a protocol from the hash tables.
  54  */
  55
  56 int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol)
  57 {
  58         int ret, hash = protocol & (MAX_INET_PROTOS - 1);
  59
  60         spin_lock_bh(&inet6_proto_lock);
  61
  62         if (inet6_protos[hash] != prot) {
  63                 ret = -1;
  64         } else {
  65                 inet6_protos[hash] = NULL;
  66                 ret = 0;
  67         }
  68
  69         spin_unlock_bh(&inet6_proto_lock);
  70
  71         synchronize_net();
  72
  73         return ret;
  74 }
  75
  76 EXPORT_SYMBOL(inet6_del_protocol);