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1629 |
jcastillo |
/*
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* IP_MASQ_VDOLIVE - VDO Live masquerading module
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*
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*
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* Version: @(#)$Id: ip_masq_vdolive.c,v 1.1 2005-12-20 10:41:09 jcastillo Exp $
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*
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* Author: Nigel Metheringham <Nigel.Metheringham@ThePLAnet.net>
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* PLAnet Online Ltd
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Thanks:
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* Thank you to VDOnet Corporation for allowing me access to
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* a protocol description without an NDA. This means that
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* this module can be distributed as source - a great help!
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*
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*/
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#include <linux/module.h>
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#include <asm/system.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include <linux/in.h>
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#include <linux/ip.h>
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#include <net/protocol.h>
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#include <net/tcp.h>
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#include <net/ip_masq.h>
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#ifndef DEBUG_CONFIG_IP_MASQ_VDOLIVE
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#define DEBUG_CONFIG_IP_MASQ_VDOLIVE 0
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#endif
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struct vdolive_priv_data {
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/* Ports used */
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unsigned short origport;
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unsigned short masqport;
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/* State of decode */
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unsigned short state;
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};
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#ifdef MODULE
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#define STATIC
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#else
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#define STATIC static
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#endif
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/*
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* List of ports (up to MAX_MASQ_APP_PORTS) to be handled by helper
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* First port is set to the default port.
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*/
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STATIC int ports[MAX_MASQ_APP_PORTS] = {7000}; /* I rely on the trailing items being set to zero */
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struct ip_masq_app *masq_incarnations[MAX_MASQ_APP_PORTS];
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static int
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masq_vdolive_init_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
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{
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MOD_INC_USE_COUNT;
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if ((ms->app_data = kmalloc(sizeof(struct vdolive_priv_data),
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GFP_ATOMIC)) == NULL)
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printk(KERN_INFO "VDOlive: No memory for application data\n");
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else
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{
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struct vdolive_priv_data *priv =
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(struct vdolive_priv_data *)ms->app_data;
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priv->origport = 0;
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priv->masqport = 0;
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priv->state = 0;
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}
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return 0;
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}
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static int
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masq_vdolive_done_1 (struct ip_masq_app *mapp, struct ip_masq *ms)
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{
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MOD_DEC_USE_COUNT;
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if (ms->app_data)
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kfree_s(ms->app_data, sizeof(struct vdolive_priv_data));
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return 0;
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}
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int
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masq_vdolive_out (struct ip_masq_app *mapp, struct ip_masq *ms, struct sk_buff **skb_p, struct device *dev)
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{
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struct sk_buff *skb;
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struct iphdr *iph;
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struct tcphdr *th;
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char *data, *data_limit;
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unsigned int tagval; /* This should be a 32 bit quantity */
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struct ip_masq *n_ms;
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struct vdolive_priv_data *priv =
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(struct vdolive_priv_data *)ms->app_data;
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/* This doesn't work at all if no priv data was allocated on startup */
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if (!priv)
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return 0;
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/* Everything running correctly already */
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if (priv->state == 3)
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return 0;
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skb = *skb_p;
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iph = skb->h.iph;
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th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
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data = (char *)&th[1];
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data_limit = skb->h.raw + skb->len;
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if (data+8 > data_limit) {
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: packet too short for ID %lx %lx\n",
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data, data_limit);
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#endif
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return 0;
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}
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memcpy(&tagval, data+4, 4);
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: packet seen, tag %ld, in initial state %d\n",
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ntohl(tagval), priv->state);
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#endif
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/* Check for leading packet ID */
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if ((ntohl(tagval) != 6) && (ntohl(tagval) != 1)) {
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: unrecognised tag %ld, in initial state %d\n",
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ntohl(tagval), priv->state);
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#endif
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return 0;
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}
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/* Check packet is long enough for data - ignore if not */
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if ((ntohl(tagval) == 6) && (data+36 > data_limit)) {
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: initial packet too short %lx %lx\n",
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data, data_limit);
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#endif
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return 0;
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} else if ((ntohl(tagval) == 1) && (data+20 > data_limit)) {
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: secondary packet too short %lx %lx\n",
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data, data_limit);
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#endif
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return 0;
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}
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/* Adjust data pointers */
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/*
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* I could check the complete protocol version tag
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* in here however I am just going to look for the
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* "VDO Live" tag in the hope that this part will
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* remain constant even if the version changes
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*/
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if (ntohl(tagval) == 6) {
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data += 24;
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: initial packet found\n");
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#endif
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} else {
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data += 8;
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: secondary packet found\n");
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#endif
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}
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if (memcmp(data, "VDO Live", 8) != 0) {
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: did not find tag\n");
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#endif
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return 0;
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}
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/*
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* The port number is the next word after the tag.
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* VDOlive encodes all of these values
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* in 32 bit words, so in this case I am
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* skipping the first 2 bytes of the next
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* word to get to the relevant 16 bits
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*/
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data += 10;
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/*
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* If we have not seen the port already,
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* set the masquerading tunnel up
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*/
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if (!priv->origport) {
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memcpy(&priv->origport, data, 2);
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: found port %d\n",
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ntohs(priv->origport));
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#endif
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/* Open up a tunnel */
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n_ms = ip_masq_new(dev, IPPROTO_UDP,
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ms->saddr, priv->origport,
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ms->daddr, 0,
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IP_MASQ_F_NO_DPORT);
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if (n_ms==NULL) {
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printk("VDOlive: unable to build UDP tunnel for %x:%x\n",
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ms->saddr, priv->origport);
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/* Leave state as unset */
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priv->origport = 0;
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return 0;
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}
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ip_masq_set_expire(n_ms, ip_masq_expire->udp_timeout);
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priv->masqport = n_ms->mport;
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} else if (memcmp(data, &(priv->origport), 2)) {
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printk("VDOlive: ports do not match\n");
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/* Write the port in anyhow!!! */
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}
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/*
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* Write masq port into packet
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*/
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memcpy(data, &(priv->masqport), 2);
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("VDOlive: rewrote port %d to %d, server %s\n",
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ntohs(priv->origport), ntohs(priv->masqport), in_ntoa(ms->saddr));
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#endif
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/*
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* Set state bit to make which bit has been done
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*/
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priv->state |= (ntohl(tagval) == 6) ? 1 : 2;
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return 0;
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}
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struct ip_masq_app ip_masq_vdolive = {
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NULL, /* next */
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"VDOlive", /* name */
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0, /* type */
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0, /* n_attach */
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masq_vdolive_init_1, /* ip_masq_init_1 */
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masq_vdolive_done_1, /* ip_masq_done_1 */
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masq_vdolive_out, /* pkt_out */
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NULL /* pkt_in */
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};
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/*
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* ip_masq_vdolive initialization
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*/
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int ip_masq_vdolive_init(void)
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{
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int i, j;
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| 255 |
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for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
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if (ports[i]) {
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if ((masq_incarnations[i] = kmalloc(sizeof(struct ip_masq_app),
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GFP_KERNEL)) == NULL)
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return -ENOMEM;
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memcpy(masq_incarnations[i], &ip_masq_vdolive, sizeof(struct ip_masq_app));
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if ((j = register_ip_masq_app(masq_incarnations[i],
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| 262 |
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IPPROTO_TCP,
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ports[i]))) {
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return j;
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}
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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printk("RealAudio: loaded support on port[%d] = %d\n",
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i, ports[i]);
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#endif
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} else {
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/* To be safe, force the incarnation table entry to NULL */
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masq_incarnations[i] = NULL;
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}
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}
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return 0;
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}
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| 277 |
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| 278 |
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/*
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| 279 |
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* ip_masq_vdolive fin.
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| 280 |
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*/
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| 281 |
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| 282 |
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int ip_masq_vdolive_done(void)
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| 283 |
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{
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| 284 |
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int i, j, k;
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| 285 |
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| 286 |
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k=0;
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| 287 |
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for (i=0; (i<MAX_MASQ_APP_PORTS); i++) {
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| 288 |
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if (masq_incarnations[i]) {
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| 289 |
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if ((j = unregister_ip_masq_app(masq_incarnations[i]))) {
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| 290 |
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k = j;
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| 291 |
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} else {
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| 292 |
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kfree(masq_incarnations[i]);
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| 293 |
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masq_incarnations[i] = NULL;
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| 294 |
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#if DEBUG_CONFIG_IP_MASQ_VDOLIVE
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| 295 |
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printk("VDOlive: unloaded support on port[%d] = %d\n",
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| 296 |
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i, ports[i]);
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| 297 |
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#endif
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| 298 |
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}
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| 299 |
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}
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| 300 |
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}
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| 301 |
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return k;
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| 302 |
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}
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| 303 |
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| 304 |
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| 305 |
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#ifdef MODULE
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| 306 |
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| 307 |
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int init_module(void)
|
| 308 |
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{
|
| 309 |
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if (ip_masq_vdolive_init() != 0)
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| 310 |
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return -EIO;
|
| 311 |
|
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register_symtab(0);
|
| 312 |
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return 0;
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| 313 |
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}
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| 314 |
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| 315 |
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void cleanup_module(void)
|
| 316 |
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{
|
| 317 |
|
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if (ip_masq_vdolive_done() != 0)
|
| 318 |
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printk("ip_masq_vdolive: can't remove module");
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| 319 |
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}
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| 320 |
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| 321 |
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#endif /* MODULE */
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