/*
* IP_MASQ_VDOLIVE - VDO Live masquerading module
*
*
* Version: @(#)$Id: ip_masq_vdolive.c,v 1.1.2.1 1997/03/04 12:04:47 davem Exp $
*
* Author: Nigel Metheringham <Nigel.Metheringham@ThePLAnet.net>
* PLAnet Online Ltd
*
* 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.
*
* Thanks:
* Thank you to VDOnet Corporation for allowing me access to
* a protocol description without an NDA. This means that
* this module can be distributed as source - a great help!
*
*/
#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>
#ifndef DEBUG_CONFIG_IP_MASQ_VDOLIVE
#define DEBUG_CONFIG_IP_MASQ_VDOLIVE 0
#endif
struct vdolive_priv_data {
/* Ports used */
unsigned short origport;
unsigned short masqport;
/* State of decode */
unsigned short state;
};
/*
* List of ports (up to MAX_MASQ_APP_PORTS) to be handled by helper
* First port is set to the default port.
*/
int ports[MAX_MASQ_APP_PORTS] = {7000}; /* I rely on the trailing items being set to zero */
struct ip_masq_app *masq_incarnations[MAX_MASQ_APP_PORTS];
static int
masq_vdolive_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
{
MOD_INC_USE_COUNT;
if ((ms->app_data = kmalloc(sizeof(struct vdolive_priv_data),
GFP_ATOMIC)) == NULL)
printk(KERN_INFO "VDOlive: No memory for application data\n");
else
{
struct vdolive_priv_data *priv =
(struct vdolive_priv_data *)ms->app_data;
priv->origport = 0;
priv->masqport = 0;
priv->state = 0;
}
return 0;
}
static int
masq_vdolive_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 vdolive_priv_data));
return 0;
}
int
masq_vdolive_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 tcphdr *th;
char *data, *data_limit;
unsigned int tagval; /* This should be a 32 bit quantity */
struct ip_masq *n_ms;
struct vdolive_priv_data *priv =
(struct vdolive_priv_data *)ms->app_data;
/* This doesn't work at all if no priv data was allocated on startup */
if (!priv)
return 0;
/* Everything running correctly already */
if (priv->state == 3)
return 0;
skb = *skb_p;
iph = skb->h.iph;
th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
data = (char *)&th[1];
data_limit = skb->h.raw + skb->len;
if (data+8 > data_limit) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: packet too short for ID %lx %lx\n",
data, data_limit);
#endif
return 0;
}
memcpy(&tagval, data+4, 4);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: packet seen, tag %ld, in initial state %d\n",
ntohl(tagval), priv->state);
#endif
/* Check for leading packet ID */
if ((ntohl(tagval) != 6) && (ntohl(tagval) != 1)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: unrecognised tag %ld, in initial state %d\n",
ntohl(tagval), priv->state);
#endif
return 0;
}
/* Check packet is long enough for data - ignore if not */
if ((ntohl(tagval) == 6) && (data+36 > data_limit)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: initial packet too short %lx %lx\n",
data, data_limit);
#endif
return 0;
} else if ((ntohl(tagval) == 1) && (data+20 > data_limit)) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: secondary packet too short %lx %lx\n",
data, data_limit);
#endif
return 0;
}
/* Adjust data pointers */
/*
* I could check the complete protocol version tag
* in here however I am just going to look for the
* "VDO Live" tag in the hope that this part will
* remain constant even if the version changes
*/
if (ntohl(tagval) == 6) {
data += 24;
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: initial packet found\n");
#endif
} else {
data += 8;
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: secondary packet found\n");
#endif
}
if (memcmp(data, "VDO Live", 8) != 0) {
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: did not find tag\n");
#endif
return 0;
}
/*
* The port number is the next word after the tag.
* VDOlive encodes all of these values
* in 32 bit words, so in this case I am
* skipping the first 2 bytes of the next
* word to get to the relevant 16 bits
*/
data += 10;
/*
* If we have not seen the port already,
* set the masquerading tunnel up
*/
if (!priv->origport) {
memcpy(&priv->origport, data, 2);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: found port %d\n",
ntohs(priv->origport));
#endif
/* Open up a tunnel */
n_ms = ip_masq_new(dev, IPPROTO_UDP,
ms->saddr, priv->origport,
ms->daddr, 0,
IP_MASQ_F_NO_DPORT);
if (n_ms==NULL) {
printk("VDOlive: unable to build UDP tunnel for %x:%x\n",
ms->saddr, priv->origport);
/* Leave state as unset */
priv->origport = 0;
return 0;
}
ip_masq_set_expire(n_ms, ip_masq_expire->udp_timeout);
priv->masqport = n_ms->mport;
} else if (memcmp(data, &(priv->origport), 2)) {
printk("VDOlive: ports do not match\n");
/* Write the port in anyhow!!! */
}
/*
* Write masq port into packet
*/
memcpy(data, &(priv->masqport), 2);
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("VDOlive: rewrote port %d to %d, server %s\n",
ntohs(priv->origport), ntohs(priv->masqport), in_ntoa(ms->saddr));
#endif
/*
* Set state bit to make which bit has been done
*/
priv->state |= (ntohl(tagval) == 6) ? 1 : 2;
return 0;
}
struct ip_masq_app ip_masq_vdolive = {
NULL, /* next */
"VDOlive", /* name */
0, /* type */
0, /* n_attach */
masq_vdolive_init_1, /* ip_masq_init_1 */
masq_vdolive_done_1, /* ip_masq_done_1 */
masq_vdolive_out, /* pkt_out */
NULL /* pkt_in */
};
/*
* ip_masq_vdolive initialization
*/
int ip_masq_vdolive_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_vdolive, sizeof(struct ip_masq_app));
if ((j = register_ip_masq_app(masq_incarnations[i],
IPPROTO_TCP,
ports[i]))) {
return j;
}
#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
printk("RealAudio: 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_vdolive fin.
*/
int ip_masq_vdolive_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_VDOLIVE
printk("VDOlive: unloaded support on port[%d] = %d\n",
i, ports[i]);
#endif
}
}
}
return k;
}
#ifdef MODULE
int init_module(void)
{
if (ip_masq_vdolive_init() != 0)
return -EIO;
register_symtab(0);
return 0;
}
void cleanup_module(void)
{
if (ip_masq_vdolive_done() != 0)
printk("ip_masq_vdolive: can't remove module");
}
#endif /* MODULE */
