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] ____cacheline_aligned_in_smp; 32 static DEFINE_SPINLOCK(inet_proto_lock); 33 34 /* 35 * Add a protocol handler to the hash tables 36 */ 37 38 int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) 39 { 40 int hash, ret; 41 42 hash = protocol & (MAX_INET_PROTOS - 1); 43 44 spin_lock_bh(&inet_proto_lock); 45 if (inet_protos[hash]) { 46 ret = -1; 47 } else { 48 inet_protos[hash] = prot; 49 ret = 0; 50 } 51 spin_unlock_bh(&inet_proto_lock); 52 53 return ret; 54 } 55 EXPORT_SYMBOL(inet_add_protocol); 56 57 /* 58 * Remove a protocol from the hash tables. 59 */ 60 61 int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) 62 { 63 int hash, ret; 64 65 hash = protocol & (MAX_INET_PROTOS - 1); 66 67 spin_lock_bh(&inet_proto_lock); 68 if (inet_protos[hash] == prot) { 69 inet_protos[hash] = NULL; 70 ret = 0; 71 } else { 72 ret = -1; 73 } 74 spin_unlock_bh(&inet_proto_lock); 75 76 synchronize_net(); 77 78 return ret; 79 } 80 EXPORT_SYMBOL(inet_del_protocol); 81