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/*

 * 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.

 *

 * Version:     $Id: protocol.c,v 1.1.1.1 2004-04-15 01:13:41 phoenix Exp $

 *

 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>

 *              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/types.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/string.h>

#include <linux/config.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/timer.h>

#include <linux/brlock.h>

#include <net/ip.h>

#include <net/protocol.h>

#include <net/tcp.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>

#define IPPROTO_PREVIOUS NULL

#ifdef CONFIG_IP_MULTICAST

static struct inet_protocol igmp_protocol = {

        handler:        igmp_rcv,

        next:           IPPROTO_PREVIOUS,

        protocol:       IPPROTO_IGMP,

        name:           "IGMP"

};

#undef  IPPROTO_PREVIOUS

#define IPPROTO_PREVIOUS &igmp_protocol

#endif

static struct inet_protocol tcp_protocol = {

        handler:        tcp_v4_rcv,

        err_handler:    tcp_v4_err,

        next:           IPPROTO_PREVIOUS,

        protocol:       IPPROTO_TCP,

        name:           "TCP"

};

#undef  IPPROTO_PREVIOUS

#define IPPROTO_PREVIOUS &tcp_protocol

static struct inet_protocol udp_protocol = {

        handler:        udp_rcv,

        err_handler:    udp_err,

        next:           IPPROTO_PREVIOUS,

        protocol:       IPPROTO_UDP,

        name:           "UDP"

};

#undef  IPPROTO_PREVIOUS

#define IPPROTO_PREVIOUS &udp_protocol

static struct inet_protocol icmp_protocol = {

        handler:        icmp_rcv,

        next:           IPPROTO_PREVIOUS,

        protocol:       IPPROTO_ICMP,

        name:           "ICMP"

};

#undef  IPPROTO_PREVIOUS

#define IPPROTO_PREVIOUS &icmp_protocol

struct inet_protocol *inet_protocol_base = IPPROTO_PREVIOUS;

struct inet_protocol *inet_protos[MAX_INET_PROTOS];

/*

 *      Add a protocol handler to the hash tables

 */

void inet_add_protocol(struct inet_protocol *prot)

{

        unsigned char hash;

        struct inet_protocol *p2;

        hash = prot->protocol & (MAX_INET_PROTOS - 1);

        br_write_lock_bh(BR_NETPROTO_LOCK);

        prot ->next = inet_protos[hash];

        inet_protos[hash] = prot;

        prot->copy = 0;

        /*

         *      Set the copy bit if we need to.

         */

        p2 = (struct inet_protocol *) prot->next;

        while (p2) {

                if (p2->protocol == prot->protocol) {

                        prot->copy = 1;

                        break;

                }

                p2 = (struct inet_protocol *) p2->next;

        }

        br_write_unlock_bh(BR_NETPROTO_LOCK);

}

/*

 *      Remove a protocol from the hash tables.

 */

int inet_del_protocol(struct inet_protocol *prot)

{

        struct inet_protocol *p;

        struct inet_protocol *lp = NULL;

        unsigned char hash;

        hash = prot->protocol & (MAX_INET_PROTOS - 1);

        br_write_lock_bh(BR_NETPROTO_LOCK);

        if (prot == inet_protos[hash]) {

                inet_protos[hash] = (struct inet_protocol *) inet_protos[hash]->next;

                br_write_unlock_bh(BR_NETPROTO_LOCK);

                return 0;

        }

        p = (struct inet_protocol *) inet_protos[hash];

        if (p != NULL && p->protocol == prot->protocol)

                lp = p;

        while (p) {

                /*

                 * We have to worry if the protocol being deleted is

                 * the last one on the list, then we may need to reset

                 * someone's copied bit.

                 */

                if (p->next && p->next == prot) {

                        /*

                         * if we are the last one with this protocol and

                         * there is a previous one, reset its copy bit.

                         */

                        if (prot->copy == 0 && lp != NULL)

                                lp->copy = 0;

                        p->next = prot->next;

                        br_write_unlock_bh(BR_NETPROTO_LOCK);

                        return 0;

                }

                if (p->next != NULL && p->next->protocol == prot->protocol)

                        lp = p->next;

                p = (struct inet_protocol *) p->next;

        }

        br_write_unlock_bh(BR_NETPROTO_LOCK);

        return -1;

}