/*
* IP_MASQ_QUAKE quake masquerading module
*
*
* Version: @(#)ip_masq_quake.c 1.00 22/02/97
*
* Author: Harald Hoyer mailto:HarryH@Royal.Net
*
*
* Fixes:
* Harald Hoyer : Unofficial Quake Specs found at
* http://www.gamers.org/dEngine/quake/spec/
* Harald Hoyer : Check for QUAKE-STRING
*
* 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/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <asm/system.h>
#include <linux/skbuff.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <net/protocol.h>
#include <net/udp.h>
#include <net/ip_masq.h>
#ifndef DEBUG_CONFIG_IP_MASQ_QUAKE
#define DEBUG_CONFIG_IP_MASQ_QUAKE 0
#endif
/*
* List of ports (up to MAX_MASQ_APP_PORTS) to be handled by helper
* First ports are set to the default port.
*/
int ports[MAX_MASQ_APP_PORTS] = { 26000, /* I rely on the trailing items */
27000 }; /* being set to zero */
struct ip_masq_app *masq_incarnations[MAX_MASQ_APP_PORTS];
typedef struct
{
__u16 type; /* (Little Endian) Type of message. */
__u16 length; /* (Little Endian) Length of message, header included. */
char message[0]; /* The contents of the message. */
} QUAKEHEADER;
struct quake_priv_data {
/* Have we seen a client connect message */
char cl_connect;
};
static int
masq_quake_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
{
MOD_INC_USE_COUNT;
if ((ms->app_data = kmalloc(sizeof(struct quake_priv_data),
GFP_ATOMIC)) == NULL)
printk(KERN_INFO "Quake: No memory for application data\n");
else
{
struct quake_priv_data *priv =
(struct quake_priv_data *)ms->app_data;
priv->cl_connect = 0;
}
return 0;
}
static int
masq_quake_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
{
MOD_DEC_USE_COUNT;
if (ms->app_data)
kfree_s(ms->app_data, sizeof(struct quake_priv_data));
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;
struct udphdr *uh;
QUAKEHEADER *qh;
__u16 udp_port;
char *data;
unsigned char code;
struct quake_priv_data *priv = (struct quake_priv_data *)ms->app_data;
if(priv->cl_connect == -1)
return 0;
skb = *skb_p;
iph = skb->h.iph;
/* iph = skb->nh.iph; */
uh = (struct udphdr *)&(((char *)iph)[iph->ihl*4]);
/* Check for lenght */
if(ntohs(uh->len) < 5)
return 0;
qh = (QUAKEHEADER *)&uh[1];
if(qh->type != 0x0080)
return 0;
code = qh->message[0];
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_in: code = %d \n", (int)code);
#endif
switch(code) {
case 0x01:
/* Connection Request */
if(ntohs(qh->length) < 0x0c) {
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_in: length < 0xc \n");
#endif
return 0;
}
data = &qh->message[1];
/* Check for stomping string */
if(memcmp(data,"QUAKE\0\3",7)) {
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: memcmp failed \n");
#endif
return 0;
}
else {
priv->cl_connect = 1;
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: memcmp ok \n");
#endif
}
break;
case 0x81:
/* Accept Connection */
if((ntohs(qh->length) < 0x09) || (priv->cl_connect == 0))
return 0;
data = &qh->message[1];
memcpy(&udp_port, data, 2);
ms->dport = htons(udp_port);
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_in: in_rewrote UDP port %d \n", udp_port);
#endif
priv->cl_connect = -1;
break;
}
return 0;
}
int
masq_quake_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
{
struct sk_buff *skb;
struct iphdr *iph;
struct udphdr *uh;
QUAKEHEADER *qh;
__u16 udp_port;
char *data;
unsigned char code;
struct ip_masq *n_ms;
struct quake_priv_data *priv = (struct quake_priv_data *)ms->app_data;
if(priv->cl_connect == -1)
return 0;
skb = *skb_p;
iph = skb->h.iph;
/* iph = skb->nh.iph; */
uh = (struct udphdr *)&(((char *)iph)[iph->ihl*4]);
/* Check for lenght */
if(ntohs(uh->len) < 5)
return 0;
qh = (QUAKEHEADER *)&uh[1];
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: qh->type = %d \n", (int)qh->type);
#endif
if(qh->type != 0x0080)
return 0;
code = qh->message[0];
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: code = %d \n", (int)code);
#endif
switch(code) {
case 0x01:
/* Connection Request */
if(ntohs(qh->length) < 0x0c) {
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: length < 0xc \n");
#endif
return 0;
}
data = &qh->message[1];
/* Check for stomping string */
if(memcmp(data,"QUAKE\0\3",7)) {
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: memcmp failed \n");
#endif
return 0;
}
else {
priv->cl_connect = 1;
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: memcmp ok \n");
#endif
}
break;
case 0x81:
/* Maybe a redirection of a quake-server at the inner side works in
the future? */
/* Accept Connection */
if((ntohs(qh->length) < 0x09) || (priv->cl_connect == 0))
return 0;
data = &qh->message[1];
memcpy(&udp_port, data, 2);
n_ms = ip_masq_new(dev, IPPROTO_UDP,
ms->saddr, htons(udp_port),
ms->daddr, ms->dport,
0);
if (n_ms==NULL)
return 0;
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake_out: out_rewrote UDP port %d -> %d\n",
udp_port, ntohs(n_ms->mport));
#endif
udp_port = ntohs(n_ms->mport);
memcpy(data, &udp_port, 2);
break;
}
return 0;
}
struct ip_masq_app ip_masq_quake = {
NULL, /* next */
"Quake", /* 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)
{
int i, j;
for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
if (ports[i]) {
if ((masq_incarnations[i] = kmalloc(sizeof(struct ip_masq_app),
GFP_KERNEL)) == NULL)
return -ENOMEM;
memcpy(masq_incarnations[i], &ip_masq_quake, sizeof(struct ip_masq_app));
if ((j = register_ip_masq_app(masq_incarnations[i],
IPPROTO_UDP,
ports[i]))) {
return j;
}
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake: loaded support on port[%d] = %d\n",
i, ports[i]);
#endif
} else {
/* To be safe, force the incarnation table entry to NULL */
masq_incarnations[i] = NULL;
}
}
return 0;
}
/*
* ip_masq_quake fin.
*/
int ip_masq_quake_done(void)
{
int i, j, k;
k=0;
for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
if (masq_incarnations[i]) {
if ((j = unregister_ip_masq_app(masq_incarnations[i]))) {
k = j;
} else {
kfree(masq_incarnations[i]);
masq_incarnations[i] = NULL;
#if DEBUG_CONFIG_IP_MASQ_QUAKE
printk("Quake: unloaded support on port[%d] = %d\n",
i, ports[i]);
#endif
}
}
}
return k;
}
#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 */
