Quake Masquerading Module

Harald Hoyer (saturn@studbox.uni-stuttgart.de)
Sun, 23 Feb 1997 05:01:36 +0100

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HI,

This quick hack to play Quake over the net with Masquerading-Support.
I know that the initial Datastream has to be checked against
a string like "\200\0\0\f\1QUAKE\0\3", but it's to late now and I have
to study a lot in the next weeks.

The File ip_masq_quake.c is attached. You may put it in your
/usr/src/linux/net/ipv4 Directory, add ip_masq_quake.o to the other
Masquerading-Modules in the Makefile, compile, load the module
and stomp the other players to the ground!

Keep on hacking,
Harald

-- 
Harald Hoyer  
saturn@studbox.uni-stuttgart.de 
http://saturnnet.wh.uni-stuttgart.de/~saturn
-------------------------------------------------------------------------
> Someone:
> Asking Linus to add such things in the kernel is as pertinent as asking 
> to still support 80286 CPU (IMHO).
We are working on it.
Alan Cox


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/*
 *		IP_MASQ_QUAKE quake masquerading module
 *
 *
 * Version:	@(#)ip_masq_quake.c 0.01   22/02/97
 *
 * Author:	Harald Hoyer
 *		
 *
 *	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 <linux/module.h>
#include <asm/system.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/ip_masq.h>




static int
masq_quake_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
{
        MOD_INC_USE_COUNT;
        return 0;
}


static int
masq_quake_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
{
	MOD_DEC_USE_COUNT;
	return 0;
}


int
masq_quake_in (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
	struct sk_buff *skb;
	struct iphdr *iph;
	__u16 *portptr, s_port;


	if(!(ms->flags & IP_MASQ_F_NO_DPORT))
		return 0;


	skb = *skb_p;
	iph = skb->nh.iph;
   
	portptr = (__u16 *)&(((char *)iph)[iph->ihl*4]);
	s_port = portptr[0];
        
	if(s_port == ms->dport)
		return 0;


	ms->dport = s_port;
	ms->flags &= ~IP_MASQ_F_NO_DPORT;
      
	return 0;
}


int
masq_quake_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
	/* SHOULD CHECK DATA "\200\0\0\f\1QUAKE\0\3" or something like that */


	if(!(ms->flags & IP_MASQ_F_NO_DPORT)) {      
		ms->flags |= IP_MASQ_F_NO_DPORT;
	}


	return 0;
}


struct ip_masq_app ip_masq_quake = {
        NULL,			/* next */
	"Quake_26",	       	/* name */
        0,                      /* type */
        0,                      /* n_attach */
        masq_quake_init_1,      /* ip_masq_init_1 */
        masq_quake_done_1,      /* ip_masq_done_1 */
        masq_quake_out,         /* pkt_out */
        masq_quake_in           /* pkt_in */
};
struct ip_masq_app ip_masq_quakenew = {
        NULL,			/* next */
	"Quake_27",	       	/* name */
        0,                      /* type */
        0,                      /* n_attach */
        masq_quake_init_1,      /* ip_masq_init_1 */
        masq_quake_done_1,      /* ip_masq_done_1 */
        masq_quake_out,         /* pkt_out */
        masq_quake_in           /* pkt_in */
};


/*
 * 	ip_masq_quake initialization
 */


int ip_masq_quake_init(void)
{
        return (register_ip_masq_app(&ip_masq_quake, IPPROTO_UDP, 26000) +
		register_ip_masq_app(&ip_masq_quakenew, IPPROTO_UDP, 27000));
}


/*
 * 	ip_masq_quake fin.
 */


int ip_masq_quake_done(void)
{
        return (unregister_ip_masq_app(&ip_masq_quake) +
                unregister_ip_masq_app(&ip_masq_quakenew));
}


#ifdef MODULE


int init_module(void)
{
        if (ip_masq_quake_init() != 0)
                return -EIO;
        register_symtab(0);
        return 0;
}


void cleanup_module(void)
{
        if (ip_masq_quake_done() != 0)
                printk("ip_masq_quake: can't remove module");
}


#endif /* MODULE */






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