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 __rcu *inet6_protos[MAX_INET_PROTOS] __read_mostly;
  29
  30 int 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 }
  37 EXPORT_SYMBOL(inet6_add_protocol);
  38
  39 /*
  40  *      Remove a protocol from the hash tables.
  41  */
  42
  43 int 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 }
  54 EXPORT_SYMBOL(inet6_del_protocol);