root/net/ipv4/protocol.c

DEFINITIONS

1. inet_add_protocol
2. inet_del_protocol

/*
 * 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 <asm/uaccess.h>
#include <asm/system.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/timer.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/icmp.h>
#include <net/udp.h>
#include <net/ipip.h>
#include <linux/igmp.h>

struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp;
static DEFINE_SPINLOCK(inet_proto_lock);

/*
 *      Add a protocol handler to the hash tables
 */

int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
{
        int hash, ret;

        hash = protocol & (MAX_INET_PROTOS - 1);

        spin_lock_bh(&inet_proto_lock);
        if (inet_protos[hash]) {
                ret = -1;
        } else {
                inet_protos[hash] = prot;
                ret = 0;
        }
        spin_unlock_bh(&inet_proto_lock);

        return ret;
}

/*
 *      Remove a protocol from the hash tables.
 */

int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
{
        int hash, ret;

        hash = protocol & (MAX_INET_PROTOS - 1);

        spin_lock_bh(&inet_proto_lock);
        if (inet_protos[hash] == prot) {
                inet_protos[hash] = NULL;
                ret = 0;
        } else {
                ret = -1;
        }
        spin_unlock_bh(&inet_proto_lock);

        synchronize_net();

        return ret;
}

EXPORT_SYMBOL(inet_add_protocol);
EXPORT_SYMBOL(inet_del_protocol);