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 * INET protocol dispatch tables. 7 * 8 * Authors: Ross Biro 9 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> 10 * 11 * Fixes: 12 * Alan Cox : Ahah! udp icmp errors don't work because 13 * udp_err is never called! 14 * Alan Cox : Added new fields for init and ready for 15 * proper fragmentation (_NO_ 4K limits!) 16 * Richard Colella : Hang on hash collision 17 * Vince Laviano : Modified inet_del_protocol() to correctly 18 * maintain copy bit. 19 * 20 * This program is free software; you can redistribute it and/or 21 * modify it under the terms of the GNU General Public License 22 * as published by the Free Software Foundation; either version 23 * 2 of the License, or (at your option) any later version. 24 */ 25 #include <linux/cache.h> 26 #include <linux/module.h> 27 #include <linux/netdevice.h> 28 #include <linux/spinlock.h> 29 #include <net/protocol.h> 30 31 const struct net_protocol *inet_protos[MAX_INET_PROTOS] __read_mostly; 32 33 /* 34 * Add a protocol handler to the hash tables 35 */ 36 37 int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) 38 { 39 int hash = protocol & (MAX_INET_PROTOS - 1); 40 41 return !cmpxchg(&inet_protos[hash], NULL, prot) ? 0 : -1; 42 } 43 EXPORT_SYMBOL(inet_add_protocol); 44 45 /* 46 * Remove a protocol from the hash tables. 47 */ 48 49 int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) 50 { 51 int ret, hash = protocol & (MAX_INET_PROTOS - 1); 52 53 ret = (cmpxchg(&inet_protos[hash], prot, NULL) == prot) ? 0 : -1; 54 55 synchronize_net(); 56 57 return ret; 58 } 59 EXPORT_SYMBOL(inet_del_protocol); 60