LXR linux/net/ipv4/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 *              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
  26#include <asm/uaccess.h>
  27#include <asm/system.h>
  28#include <linux/module.h>
  29#include <linux/types.h>
  30#include <linux/kernel.h>
  31#include <linux/string.h>
  32#include <linux/socket.h>
  33#include <linux/in.h>
  34#include <linux/inet.h>
  35#include <linux/netdevice.h>
  36#include <linux/timer.h>
  37#include <net/ip.h>
  38#include <net/protocol.h>
  39#include <linux/skbuff.h>
  40#include <net/sock.h>
  41#include <net/icmp.h>
  42#include <net/udp.h>
  43#include <net/ipip.h>
  44#include <linux/igmp.h>
  45
  46struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp;
  47static DEFINE_SPINLOCK(inet_proto_lock);
  48
  49/*
  50 *      Add a protocol handler to the hash tables
  51 */
  52
  53int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
  54{
  55        int hash, ret;
  56
  57        hash = protocol & (MAX_INET_PROTOS - 1);
  58
  59        spin_lock_bh(&inet_proto_lock);
  60        if (inet_protos[hash]) {
  61                ret = -1;
  62        } else {
  63                inet_protos[hash] = prot;
  64                ret = 0;
  65        }
  66        spin_unlock_bh(&inet_proto_lock);
  67
  68        return ret;
  69}
  70
  71/*
  72 *      Remove a protocol from the hash tables.
  73 */
  74
  75int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
  76{
  77        int hash, ret;
  78
  79        hash = protocol & (MAX_INET_PROTOS - 1);
  80
  81        spin_lock_bh(&inet_proto_lock);
  82        if (inet_protos[hash] == prot) {
  83                inet_protos[hash] = NULL;
  84                ret = 0;
  85        } else {
  86                ret = -1;
  87        }
  88        spin_unlock_bh(&inet_proto_lock);
  89
  90        synchronize_net();
  91
  92        return ret;
  93}
  94
  95EXPORT_SYMBOL(inet_add_protocol);
  96EXPORT_SYMBOL(inet_del_protocol);
  97