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net/ipv4/protocol.c 2.28 KB
81f7e3824   Eric Lee   Initial Release, ...
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  /*
   * INET		An implementation of the TCP/IP protocol suite for the LINUX
   *		operating system.  INET is implemented using the  BSD Socket
   *		interface as the means of communication with the user level.
   *
   *		INET protocol dispatch tables.
   *
   * Authors:	Ross Biro
   *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *
   * Fixes:
   *		Alan Cox	: Ahah! udp icmp errors don't work because
   *				  udp_err is never called!
   *		Alan Cox	: Added new fields for init and ready for
   *				  proper fragmentation (_NO_ 4K limits!)
   *		Richard Colella	: Hang on hash collision
   *		Vince Laviano	: Modified inet_del_protocol() to correctly
   *				  maintain copy bit.
   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.
   */
  #include <linux/cache.h>
  #include <linux/module.h>
  #include <linux/netdevice.h>
  #include <linux/spinlock.h>
  #include <net/protocol.h>
  
  struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
  const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
  EXPORT_SYMBOL(inet_offloads);
  
  int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
  {
  	if (!prot->netns_ok) {
  		pr_err("Protocol %u is not namespace aware, cannot register.
  ",
  			protocol);
  		return -EINVAL;
  	}
  
  	return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
  			NULL, prot) ? 0 : -1;
  }
  EXPORT_SYMBOL(inet_add_protocol);
  
  int inet_add_offload(const struct net_offload *prot, unsigned char protocol)
  {
  	return !cmpxchg((const struct net_offload **)&inet_offloads[protocol],
  			NULL, prot) ? 0 : -1;
  }
  EXPORT_SYMBOL(inet_add_offload);
  
  int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
  {
  	int ret;
  
  	ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol],
  		       prot, NULL) == prot) ? 0 : -1;
  
  	synchronize_net();
  
  	return ret;
  }
  EXPORT_SYMBOL(inet_del_protocol);
  
  int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
  {
  	int ret;
  
  	ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
  		       prot, NULL) == prot) ? 0 : -1;
  
  	synchronize_net();
  
  	return ret;
  }
  EXPORT_SYMBOL(inet_del_offload);