/* * 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> const struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly; /* *	Add a protocol handler to the hash tables */ int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol){	int hash = protocol & (MAX_INET_PROTOS - 1); 	return !cmpxchg((const struct net_protocol **)&inet_protos[hash],			NULL, prot) ? 0 : -1;}EXPORT_SYMBOL(inet_add_protocol); /* *	Remove a protocol from the hash tables. */ int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol){	int ret, hash = protocol & (MAX_INET_PROTOS - 1); 	ret = (cmpxchg((const struct net_protocol **)&inet_protos[hash],		       prot, NULL) == prot) ? 0 : -1; 	synchronize_net(); 	return ret;}EXPORT_SYMBOL(inet_del_protocol);