LXR linux-bk/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 * Version:     $Id: protocol.c,v 1.14 2001/05/18 02:25:49 davem Exp $
   9 *
  10 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
  11 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
  12 *
  13 * Fixes:
  14 *              Alan Cox        : Ahah! udp icmp errors don't work because
  15 *                                udp_err is never called!
  16 *              Alan Cox        : Added new fields for init and ready for
  17 *                                proper fragmentation (_NO_ 4K limits!)
  18 *              Richard Colella : Hang on hash collision
  19 *              Vince Laviano   : Modified inet_del_protocol() to correctly
  20 *                                maintain copy bit.
  21 *
  22 *              This program is free software; you can redistribute it and/or
  23 *              modify it under the terms of the GNU General Public License
  24 *              as published by the Free Software Foundation; either version
  25 *              2 of the License, or (at your option) any later version.
  26 */
  27
  28#include <asm/uaccess.h>
  29#include <asm/system.h>
  30#include <linux/module.h>
  31#include <linux/types.h>
  32#include <linux/kernel.h>
  33#include <linux/sched.h>
  34#include <linux/string.h>
  35#include <linux/config.h>
  36#include <linux/socket.h>
  37#include <linux/in.h>
  38#include <linux/inet.h>
  39#include <linux/netdevice.h>
  40#include <linux/timer.h>
  41#include <net/ip.h>
  42#include <net/protocol.h>
  43#include <net/tcp.h>
  44#include <linux/skbuff.h>
  45#include <net/sock.h>
  46#include <net/icmp.h>
  47#include <net/udp.h>
  48#include <net/ipip.h>
  49#include <linux/igmp.h>
  50
  51struct net_protocol *inet_protos[MAX_INET_PROTOS];
  52static DEFINE_SPINLOCK(inet_proto_lock);
  53
  54/*
  55 *      Add a protocol handler to the hash tables
  56 */
  57
  58int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
  59{
  60        int hash, ret;
  61
  62        hash = protocol & (MAX_INET_PROTOS - 1);
  63
  64        spin_lock_bh(&inet_proto_lock);
  65        if (inet_protos[hash]) {
  66                ret = -1;
  67        } else {
  68                inet_protos[hash] = prot;
  69                ret = 0;
  70        }
  71        spin_unlock_bh(&inet_proto_lock);
  72
  73        return ret;
  74}
  75
  76/*
  77 *      Remove a protocol from the hash tables.
  78 */
  79 
  80int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
  81{
  82        int hash, ret;
  83
  84        hash = protocol & (MAX_INET_PROTOS - 1);
  85
  86        spin_lock_bh(&inet_proto_lock);
  87        if (inet_protos[hash] == prot) {
  88                inet_protos[hash] = NULL;
  89                ret = 0;
  90        } else {
  91                ret = -1;
  92        }
  93        spin_unlock_bh(&inet_proto_lock);
  94
  95        synchronize_net();
  96
  97        return ret;
  98}
  99
 100EXPORT_SYMBOL(inet_add_protocol);
 101EXPORT_SYMBOL(inet_del_protocol);
 102