LXR linux/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
  28const struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS] __read_mostly;
  29
  30int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol)
  31{
  32        int hash = protocol & (MAX_INET_PROTOS - 1);
  33
  34        return !cmpxchg((const struct inet6_protocol **)&inet6_protos[hash],
  35                        NULL, prot) ? 0 : -1;
  36}
  37EXPORT_SYMBOL(inet6_add_protocol);
  38
  39/*
  40 *      Remove a protocol from the hash tables.
  41 */
  42
  43int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol)
  44{
  45        int ret, hash = protocol & (MAX_INET_PROTOS - 1);
  46
  47        ret = (cmpxchg((const struct inet6_protocol **)&inet6_protos[hash],
  48                       prot, NULL) == prot) ? 0 : -1;
  49
  50        synchronize_net();
  51
  52        return ret;
  53}
  54EXPORT_SYMBOL(inet6_del_protocol);
  55