fix nat helpers for ipv4, add rtsp nat helper

1 files changed, 2316 insertions, 0 deletions

diff --git a/target/linux/patches/2.6.33/rtsp.patch b/target/linux/patches/2.6.33/rtsp.patch
new file mode 100644
index 000000000..317c06d8e
--- /dev/null
+++ b/target/linux/patches/2.6.33/rtsp.patch
@@ -0,0 +1,2316 @@
+diff -Nur linux-2.6.33.orig/include/linux/netfilter/nf_conntrack_rtsp.h linux-2.6.33/include/linux/netfilter/nf_conntrack_rtsp.h
+--- linux-2.6.33.orig/include/linux/netfilter/nf_conntrack_rtsp.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.6.33/include/linux/netfilter/nf_conntrack_rtsp.h	2010-04-25 01:09:20.000000000 +0200
+@@ -0,0 +1,63 @@
++/*
++ * RTSP extension for IP connection tracking.
++ * (C) 2003 by Tom Marshall <tmarshall at real.com>
++ * based on ip_conntrack_irc.h
++ *
++ *      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.
++ */
++#ifndef _IP_CONNTRACK_RTSP_H
++#define _IP_CONNTRACK_RTSP_H
++
++//#define IP_NF_RTSP_DEBUG 1
++#define IP_NF_RTSP_VERSION "0.6.21"
++
++#ifdef __KERNEL__
++/* port block types */
++typedef enum {
++    pb_single,  /* client_port=x */
++    pb_range,   /* client_port=x-y */
++    pb_discon   /* client_port=x/y (rtspbis) */
++} portblock_t;
++
++/* We record seq number and length of rtsp headers here, all in host order. */
++
++/*
++ * This structure is per expected connection.  It is a member of struct
++ * ip_conntrack_expect.  The TCP SEQ for the conntrack expect is stored
++ * there and we are expected to only store the length of the data which
++ * needs replaced.  If a packet contains multiple RTSP messages, we create
++ * one expected connection per message.
++ *
++ * We use these variables to mark the entire header block.  This may seem
++ * like overkill, but the nature of RTSP requires it.  A header may appear
++ * multiple times in a message.  We must treat two Transport headers the
++ * same as one Transport header with two entries.
++ */
++struct ip_ct_rtsp_expect
++{
++    u_int32_t   len;        /* length of header block */
++    portblock_t pbtype;     /* Type of port block that was requested */
++    u_int16_t   loport;     /* Port that was requested, low or first */
++    u_int16_t   hiport;     /* Port that was requested, high or second */
++#if 0
++    uint        method;     /* RTSP method */
++    uint        cseq;       /* CSeq from request */
++#endif
++};
++
++extern unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
++				 enum ip_conntrack_info ctinfo,
++				 unsigned int matchoff, unsigned int matchlen,
++				 struct ip_ct_rtsp_expect *prtspexp,
++				 struct nf_conntrack_expect *exp);
++
++extern void (*nf_nat_rtsp_hook_expectfn)(struct nf_conn *ct, struct nf_conntrack_expect *exp);
++
++#define RTSP_PORT   554
++
++#endif /* __KERNEL__ */
++
++#endif /* _IP_CONNTRACK_RTSP_H */
+diff -Nur linux-2.6.33.orig/include/linux/netfilter_helpers.h linux-2.6.33/include/linux/netfilter_helpers.h
+--- linux-2.6.33.orig/include/linux/netfilter_helpers.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.6.33/include/linux/netfilter_helpers.h	2010-04-25 01:09:20.000000000 +0200
+@@ -0,0 +1,133 @@
++/*
++ * Helpers for netfiler modules.  This file provides implementations for basic
++ * functions such as strncasecmp(), etc.
++ *
++ * gcc will warn for defined but unused functions, so we only include the
++ * functions requested.  The following macros are used:
++ *   NF_NEED_STRNCASECMP        nf_strncasecmp()
++ *   NF_NEED_STRTOU16           nf_strtou16()
++ *   NF_NEED_STRTOU32           nf_strtou32()
++ */
++#ifndef _NETFILTER_HELPERS_H
++#define _NETFILTER_HELPERS_H
++
++/* Only include these functions for kernel code. */
++#ifdef __KERNEL__
++
++#include <linux/ctype.h>
++#define iseol(c) ( (c) == '\r' || (c) == '\n' )
++
++/*
++ * The standard strncasecmp()
++ */
++#ifdef NF_NEED_STRNCASECMP
++static int
++nf_strncasecmp(const char* s1, const char* s2, u_int32_t len)
++{
++    if (s1 == NULL || s2 == NULL)
++    {
++        if (s1 == NULL && s2 == NULL)
++        {
++            return 0;
++        }
++        return (s1 == NULL) ? -1 : 1;
++    }
++    while (len > 0 && tolower(*s1) == tolower(*s2))
++    {
++        len--;
++        s1++;
++        s2++;
++    }
++    return ( (len == 0) ? 0 : (tolower(*s1) - tolower(*s2)) );
++}
++#endif /* NF_NEED_STRNCASECMP */
++
++/*
++ * Parse a string containing a 16-bit unsigned integer.
++ * Returns the number of chars used, or zero if no number is found.
++ */
++#ifdef NF_NEED_STRTOU16
++static int
++nf_strtou16(const char* pbuf, u_int16_t* pval)
++{
++    int n = 0;
++
++    *pval = 0;
++    while (isdigit(pbuf[n]))
++    {
++        *pval = (*pval * 10) + (pbuf[n] - '0');
++        n++;
++    }
++
++    return n;
++}
++#endif /* NF_NEED_STRTOU16 */
++
++/*
++ * Parse a string containing a 32-bit unsigned integer.
++ * Returns the number of chars used, or zero if no number is found.
++ */
++#ifdef NF_NEED_STRTOU32
++static int
++nf_strtou32(const char* pbuf, u_int32_t* pval)
++{
++    int n = 0;
++
++    *pval = 0;
++    while (pbuf[n] >= '0' && pbuf[n] <= '9')
++    {
++        *pval = (*pval * 10) + (pbuf[n] - '0');
++        n++;
++    }
++
++    return n;
++}
++#endif /* NF_NEED_STRTOU32 */
++
++/*
++ * Given a buffer and length, advance to the next line and mark the current
++ * line.
++ */
++#ifdef NF_NEED_NEXTLINE
++static int
++nf_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
++{
++    uint    off = *poff;
++    uint    physlen = 0;
++
++    if (off >= len)
++    {
++        return 0;
++    }
++
++    while (p[off] != '\n')
++    {
++        if (len-off <= 1)
++        {
++            return 0;
++        }
++
++        physlen++;
++        off++;
++    }
++
++    /* if we saw a crlf, physlen needs adjusted */
++    if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
++    {
++        physlen--;
++    }
++
++    /* advance past the newline */
++    off++;
++
++    *plineoff = *poff;
++    *plinelen = physlen;
++    *poff = off;
++
++    return 1;
++}
++#endif /* NF_NEED_NEXTLINE */
++
++#endif /* __KERNEL__ */
++
++#endif /* _NETFILTER_HELPERS_H */
+diff -Nur linux-2.6.33.orig/include/linux/netfilter_mime.h linux-2.6.33/include/linux/netfilter_mime.h
+--- linux-2.6.33.orig/include/linux/netfilter_mime.h	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.6.33/include/linux/netfilter_mime.h	2010-04-25 01:09:20.000000000 +0200
+@@ -0,0 +1,89 @@
++/*
++ * MIME functions for netfilter modules.  This file provides implementations
++ * for basic MIME parsing.  MIME headers are used in many protocols, such as
++ * HTTP, RTSP, SIP, etc.
++ *
++ * gcc will warn for defined but unused functions, so we only include the
++ * functions requested.  The following macros are used:
++ *   NF_NEED_MIME_NEXTLINE      nf_mime_nextline()
++ */
++#ifndef _NETFILTER_MIME_H
++#define _NETFILTER_MIME_H
++
++/* Only include these functions for kernel code. */
++#ifdef __KERNEL__
++
++#include <linux/ctype.h>
++
++/*
++ * Given a buffer and length, advance to the next line and mark the current
++ * line.  If the current line is empty, *plinelen will be set to zero.  If
++ * not, it will be set to the actual line length (including CRLF).
++ *
++ * 'line' in this context means logical line (includes LWS continuations).
++ * Returns 1 on success, 0 on failure.
++ */
++#ifdef NF_NEED_MIME_NEXTLINE
++static int
++nf_mime_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
++{
++    uint    off = *poff;
++    uint    physlen = 0;
++    int     is_first_line = 1;
++
++    if (off >= len)
++    {
++        return 0;
++    }
++
++    do
++    {
++        while (p[off] != '\n')
++        {
++            if (len-off <= 1)
++            {
++                return 0;
++            }
++
++            physlen++;
++            off++;
++        }
++
++        /* if we saw a crlf, physlen needs adjusted */
++        if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
++        {
++            physlen--;
++        }
++
++        /* advance past the newline */
++        off++;
++
++        /* check for an empty line */
++        if (physlen == 0)
++        {
++            break;
++        }
++
++        /* check for colon on the first physical line */
++        if (is_first_line)
++        {
++            is_first_line = 0;
++            if (memchr(p+(*poff), ':', physlen) == NULL)
++            {
++                return 0;
++            }
++        }
++    }
++    while (p[off] == ' ' || p[off] == '\t');
++
++    *plineoff = *poff;
++    *plinelen = (physlen == 0) ? 0 : (off - *poff);
++    *poff = off;
++
++    return 1;
++}
++#endif /* NF_NEED_MIME_NEXTLINE */
++
++#endif /* __KERNEL__ */
++
++#endif /* _NETFILTER_MIME_H */
+diff -Nur linux-2.6.33.orig/net/ipv4/netfilter/Kconfig linux-2.6.33/net/ipv4/netfilter/Kconfig
+--- linux-2.6.33.orig/net/ipv4/netfilter/Kconfig	2010-02-24 19:52:17.000000000 +0100
++++ linux-2.6.33/net/ipv4/netfilter/Kconfig	2010-04-25 01:09:20.000000000 +0200
+@@ -257,6 +257,11 @@
+ 	depends on NF_CONNTRACK && NF_NAT
+ 	default NF_NAT && NF_CONNTRACK_IRC
+ 
++config NF_NAT_RTSP
++	tristate
++ 	depends on IP_NF_IPTABLES && NF_CONNTRACK && NF_NAT
++ 	default NF_NAT && NF_CONNTRACK_RTSP
++
+ config NF_NAT_TFTP
+ 	tristate
+ 	depends on NF_CONNTRACK && NF_NAT
+diff -Nur linux-2.6.33.orig/net/ipv4/netfilter/Makefile linux-2.6.33/net/ipv4/netfilter/Makefile
+--- linux-2.6.33.orig/net/ipv4/netfilter/Makefile	2010-02-24 19:52:17.000000000 +0100
++++ linux-2.6.33/net/ipv4/netfilter/Makefile	2010-04-25 01:09:20.000000000 +0200
+@@ -26,6 +26,7 @@
+ obj-$(CONFIG_NF_NAT_FTP) += nf_nat_ftp.o
+ obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
+ obj-$(CONFIG_NF_NAT_IRC) += nf_nat_irc.o
++obj-$(CONFIG_NF_NAT_RTSP) += nf_nat_rtsp.o
+ obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
+ obj-$(CONFIG_NF_NAT_SIP) += nf_nat_sip.o
+ obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
+diff -Nur linux-2.6.33.orig/net/ipv4/netfilter/nf_nat_rtsp.c linux-2.6.33/net/ipv4/netfilter/nf_nat_rtsp.c
+--- linux-2.6.33.orig/net/ipv4/netfilter/nf_nat_rtsp.c	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.6.33/net/ipv4/netfilter/nf_nat_rtsp.c	2010-04-25 01:09:20.000000000 +0200
+@@ -0,0 +1,496 @@
++/*
++ * RTSP extension for TCP NAT alteration
++ * (C) 2003 by Tom Marshall <tmarshall at real.com>
++ * based on ip_nat_irc.c
++ *
++ *      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.
++ *
++ * Module load syntax:
++ *      insmod nf_nat_rtsp.o ports=port1,port2,...port<MAX_PORTS>
++ *                           stunaddr=<address>
++ *                           destaction=[auto|strip|none]
++ *
++ * If no ports are specified, the default will be port 554 only.
++ *
++ * stunaddr specifies the address used to detect that a client is using STUN.
++ * If this address is seen in the destination parameter, it is assumed that
++ * the client has already punched a UDP hole in the firewall, so we don't
++ * mangle the client_port.  If none is specified, it is autodetected.  It
++ * only needs to be set if you have multiple levels of NAT.  It should be
++ * set to the external address that the STUN clients detect.  Note that in
++ * this case, it will not be possible for clients to use UDP with servers
++ * between the NATs.
++ *
++ * If no destaction is specified, auto is used.
++ *   destaction=auto:  strip destination parameter if it is not stunaddr.
++ *   destaction=strip: always strip destination parameter (not recommended).
++ *   destaction=none:  do not touch destination parameter (not recommended).
++ */
++
++#include <linux/module.h>
++#include <net/tcp.h>
++#include <net/netfilter/nf_nat_helper.h>
++#include <net/netfilter/nf_nat_rule.h>
++#include <linux/netfilter/nf_conntrack_rtsp.h>
++#include <net/netfilter/nf_conntrack_expect.h>
++
++#include <linux/inet.h>
++#include <linux/ctype.h>
++#define NF_NEED_STRNCASECMP
++#define NF_NEED_STRTOU16
++#include <linux/netfilter_helpers.h>
++#define NF_NEED_MIME_NEXTLINE
++#include <linux/netfilter_mime.h>
++
++#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
++#if 0
++#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
++#else
++#define DEBUGP(fmt, args...)
++#endif
++
++#define MAX_PORTS       8
++#define DSTACT_AUTO     0
++#define DSTACT_STRIP    1
++#define DSTACT_NONE     2
++
++static char*    stunaddr = NULL;
++static char*    destaction = NULL;
++
++static u_int32_t extip = 0;
++static int       dstact = 0;
++
++MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
++MODULE_DESCRIPTION("RTSP network address translation module");
++MODULE_LICENSE("GPL");
++module_param(stunaddr, charp, 0644);
++MODULE_PARM_DESC(stunaddr, "Address for detecting STUN");
++module_param(destaction, charp, 0644);
++MODULE_PARM_DESC(destaction, "Action for destination parameter (auto/strip/none)");
++
++#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
++
++/*** helper functions ***/
++
++static void
++get_skb_tcpdata(struct sk_buff* skb, char** pptcpdata, uint* ptcpdatalen)
++{
++    struct iphdr*   iph  = ip_hdr(skb);
++    struct tcphdr*  tcph = (void *)iph + ip_hdrlen(skb);
++
++    *pptcpdata = (char*)tcph +  tcph->doff*4;
++    *ptcpdatalen = ((char*)skb_transport_header(skb) + skb->len) - *pptcpdata;
++}
++
++/*** nat functions ***/
++
++/*
++ * Mangle the "Transport:" header:
++ *   - Replace all occurences of "client_port=<spec>"
++ *   - Handle destination parameter
++ *
++ * In:
++ *   ct, ctinfo = conntrack context
++ *   skb        = packet
++ *   tranoff    = Transport header offset from TCP data
++ *   tranlen    = Transport header length (incl. CRLF)
++ *   rport_lo   = replacement low  port (host endian)
++ *   rport_hi   = replacement high port (host endian)
++ *
++ * Returns packet size difference.
++ *
++ * Assumes that a complete transport header is present, ending with CR or LF
++ */
++static int
++rtsp_mangle_tran(enum ip_conntrack_info ctinfo,
++                 struct nf_conntrack_expect* exp,
++								 struct ip_ct_rtsp_expect* prtspexp,
++                 struct sk_buff* skb, uint tranoff, uint tranlen)
++{
++    char*       ptcp;
++    uint        tcplen;
++    char*       ptran;
++    char        rbuf1[16];      /* Replacement buffer (one port) */
++    uint        rbuf1len;       /* Replacement len (one port) */
++    char        rbufa[16];      /* Replacement buffer (all ports) */
++    uint        rbufalen;       /* Replacement len (all ports) */
++    u_int32_t   newip;
++    u_int16_t   loport, hiport;
++    uint        off = 0;
++    uint        diff;           /* Number of bytes we removed */
++
++    struct nf_conn *ct = exp->master;
++    struct nf_conntrack_tuple *t;
++
++    char    szextaddr[15+1];
++    uint    extaddrlen;
++    int     is_stun;
++
++    get_skb_tcpdata(skb, &ptcp, &tcplen);
++    ptran = ptcp+tranoff;
++
++    if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen ||
++        tranlen < 10 || !iseol(ptran[tranlen-1]) ||
++        nf_strncasecmp(ptran, "Transport:", 10) != 0)
++    {
++        INFOP("sanity check failed\n");
++        return 0;
++    }
++    off += 10;
++    SKIP_WSPACE(ptcp+tranoff, tranlen, off);
++
++    newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
++    t = &exp->tuple;
++    t->dst.u3.ip = newip;
++
++    extaddrlen = extip ? sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(extip))
++                       : sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(newip));
++    DEBUGP("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto"));
++
++    rbuf1len = rbufalen = 0;
++    switch (prtspexp->pbtype)
++    {
++    case pb_single:
++        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
++        {
++            t->dst.u.udp.port = htons(loport);
++            if (nf_ct_expect_related(exp) == 0)
++            {
++                DEBUGP("using port %hu\n", loport);
++                break;
++            }
++        }
++        if (loport != 0)
++        {
++            rbuf1len = sprintf(rbuf1, "%hu", loport);
++            rbufalen = sprintf(rbufa, "%hu", loport);
++        }
++        break;
++    case pb_range:
++        for (loport = prtspexp->loport; loport != 0; loport += 2) /* XXX: improper wrap? */
++        {
++            t->dst.u.udp.port = htons(loport);
++            if (nf_ct_expect_related(exp) == 0)
++            {
++                hiport = loport + ~exp->mask.src.u.udp.port;
++                DEBUGP("using ports %hu-%hu\n", loport, hiport);
++                break;
++            }
++        }
++        if (loport != 0)
++        {
++            rbuf1len = sprintf(rbuf1, "%hu", loport);
++            rbufalen = sprintf(rbufa, "%hu-%hu", loport, loport+1);
++        }
++        break;
++    case pb_discon:
++        for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */
++        {
++            t->dst.u.udp.port = htons(loport);
++            if (nf_ct_expect_related(exp) == 0)
++            {
++                DEBUGP("using port %hu (1 of 2)\n", loport);
++                break;
++            }
++        }
++        for (hiport = prtspexp->hiport; hiport != 0; hiport++) /* XXX: improper wrap? */
++        {
++            t->dst.u.udp.port = htons(hiport);
++            if (nf_ct_expect_related(exp) == 0)
++            {
++                DEBUGP("using port %hu (2 of 2)\n", hiport);
++                break;
++            }
++        }
++        if (loport != 0 && hiport != 0)
++        {
++            rbuf1len = sprintf(rbuf1, "%hu", loport);
++            if (hiport == loport+1)
++            {
++                rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport);
++            }
++            else
++            {
++                rbufalen = sprintf(rbufa, "%hu/%hu", loport, hiport);
++            }
++        }
++        break;
++    }
++
++    if (rbuf1len == 0)
++    {
++        return 0;   /* cannot get replacement port(s) */
++    }
++
++    /* Transport: tran;field;field=val,tran;field;field=val,... */
++    while (off < tranlen)
++    {
++        uint        saveoff;
++        const char* pparamend;
++        uint        nextparamoff;
++
++        pparamend = memchr(ptran+off, ',', tranlen-off);
++        pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
++        nextparamoff = pparamend-ptcp;
++
++        /*
++         * We pass over each param twice.  On the first pass, we look for a
++         * destination= field.  It is handled by the security policy.  If it
++         * is present, allowed, and equal to our external address, we assume
++         * that STUN is being used and we leave the client_port= field alone.
++         */
++        is_stun = 0;
++        saveoff = off;
++        while (off < nextparamoff)
++        {
++            const char* pfieldend;
++            uint        nextfieldoff;
++
++            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
++            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
++
++            if (dstact != DSTACT_NONE && strncmp(ptran+off, "destination=", 12) == 0)
++            {
++                if (strncmp(ptran+off+12, szextaddr, extaddrlen) == 0)
++                {
++                    is_stun = 1;
++                }
++                if (dstact == DSTACT_STRIP || (dstact == DSTACT_AUTO && !is_stun))
++                {
++                    diff = nextfieldoff-off;
++                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
++                                                         off, diff, NULL, 0))
++                    {
++                        /* mangle failed, all we can do is bail */
++			nf_ct_unexpect_related(exp);
++                        return 0;
++                    }
++                    get_skb_tcpdata(skb, &ptcp, &tcplen);
++                    ptran = ptcp+tranoff;
++                    tranlen -= diff;
++                    nextparamoff -= diff;
++                    nextfieldoff -= diff;
++                }
++            }
++
++            off = nextfieldoff;
++        }
++        if (is_stun)
++        {
++            continue;
++        }
++        off = saveoff;
++        while (off < nextparamoff)
++        {
++            const char* pfieldend;
++            uint        nextfieldoff;
++
++            pfieldend = memchr(ptran+off, ';', nextparamoff-off);
++            nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
++
++            if (strncmp(ptran+off, "client_port=", 12) == 0)
++            {
++                u_int16_t   port;
++                uint        numlen;
++                uint        origoff;
++                uint        origlen;
++                char*       rbuf    = rbuf1;
++                uint        rbuflen = rbuf1len;
++
++                off += 12;
++                origoff = (ptran-ptcp)+off;
++                origlen = 0;
++                numlen = nf_strtou16(ptran+off, &port);
++                off += numlen;
++                origlen += numlen;
++                if (port != prtspexp->loport)
++                {
++                    DEBUGP("multiple ports found, port %hu ignored\n", port);
++                }
++                else
++                {
++                    if (ptran[off] == '-' || ptran[off] == '/')
++                    {
++                        off++;
++                        origlen++;
++                        numlen = nf_strtou16(ptran+off, &port);
++                        off += numlen;
++                        origlen += numlen;
++                        rbuf = rbufa;
++                        rbuflen = rbufalen;
++                    }
++
++                    /*
++                     * note we cannot just memcpy() if the sizes are the same.
++                     * the mangle function does skb resizing, checks for a
++                     * cloned skb, and updates the checksums.
++                     *
++                     * parameter 4 below is offset from start of tcp data.
++                     */
++                    diff = origlen-rbuflen;
++                    if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
++                                              origoff, origlen, rbuf, rbuflen))
++                    {
++                        /* mangle failed, all we can do is bail */
++			nf_ct_unexpect_related(exp);
++                        return 0;
++                    }
++                    get_skb_tcpdata(skb, &ptcp, &tcplen);
++                    ptran = ptcp+tranoff;
++                    tranlen -= diff;
++                    nextparamoff -= diff;
++                    nextfieldoff -= diff;
++                }
++            }
++
++            off = nextfieldoff;
++        }
++
++        off = nextparamoff;
++    }
++
++    return 1;
++}
++
++static uint
++help_out(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
++	 unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
++	 struct nf_conntrack_expect* exp)
++{
++    char*   ptcp;
++    uint    tcplen;
++    uint    hdrsoff;
++    uint    hdrslen;
++    uint    lineoff;
++    uint    linelen;
++    uint    off;
++
++    //struct iphdr* iph = (struct iphdr*)skb->nh.iph;
++    //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4);
++
++    get_skb_tcpdata(skb, &ptcp, &tcplen);
++    hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq);
++    hdrslen = matchlen;
++    off = hdrsoff;
++    DEBUGP("NAT rtsp help_out\n");
++
++    while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen))
++    {
++        if (linelen == 0)
++        {
++            break;
++        }
++        if (off > hdrsoff+hdrslen)
++        {
++            INFOP("!! overrun !!");
++            break;
++        }
++        DEBUGP("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
++
++        if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0)
++        {
++            uint oldtcplen = tcplen;
++	    DEBUGP("hdr: Transport\n");
++            if (!rtsp_mangle_tran(ctinfo, exp, prtspexp, skb, lineoff, linelen))
++            {
++		DEBUGP("hdr: Transport mangle failed");
++                break;
++            }
++            get_skb_tcpdata(skb, &ptcp, &tcplen);
++            hdrslen -= (oldtcplen-tcplen);
++            off -= (oldtcplen-tcplen);
++            lineoff -= (oldtcplen-tcplen);
++            linelen -= (oldtcplen-tcplen);
++            DEBUGP("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
++        }
++    }
++
++    return NF_ACCEPT;
++}
++
++static unsigned int
++help(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
++     unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
++     struct nf_conntrack_expect* exp)
++{
++    int dir = CTINFO2DIR(ctinfo);
++    int rc = NF_ACCEPT;
++
++    switch (dir)
++    {
++    case IP_CT_DIR_ORIGINAL:
++        rc = help_out(skb, ctinfo, matchoff, matchlen, prtspexp, exp);
++        break;
++    case IP_CT_DIR_REPLY:
++	DEBUGP("unmangle ! %u\n", ctinfo);
++    	/* XXX: unmangle */
++	rc = NF_ACCEPT;
++        break;
++    }
++    //UNLOCK_BH(&ip_rtsp_lock);
++
++    return rc;
++}
++
++static void expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
++{
++    struct nf_nat_multi_range_compat mr;
++    u_int32_t newdstip, newsrcip, newip;
++
++    struct nf_conn *master = ct->master;
++
++    newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
++    newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
++    //FIXME (how to port that ?)
++    //code from 2.4 : newip = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) ? newsrcip : newdstip;
++    newip = newdstip;
++
++    DEBUGP("newsrcip=%u.%u.%u.%u, newdstip=%u.%u.%u.%u, newip=%u.%u.%u.%u\n",
++           NIPQUAD(newsrcip), NIPQUAD(newdstip), NIPQUAD(newip));
++
++    mr.rangesize = 1;
++    // We don't want to manip the per-protocol, just the IPs.
++    mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
++    mr.range[0].min_ip = mr.range[0].max_ip = newip;
++
++    nf_nat_setup_info(ct, &mr.range[0], IP_NAT_MANIP_DST);
++}
++
++
++static void __exit fini(void)
++{
++	nf_nat_rtsp_hook = NULL;
++        nf_nat_rtsp_hook_expectfn = NULL;
++	synchronize_net();
++}
++
++static int __init init(void)
++{
++	printk("nf_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n");
++
++	BUG_ON(nf_nat_rtsp_hook);
++	nf_nat_rtsp_hook = help;
++        nf_nat_rtsp_hook_expectfn = &expected;
++
++	if (stunaddr != NULL)
++		extip = in_aton(stunaddr);
++
++	if (destaction != NULL) {
++	        if (strcmp(destaction, "auto") == 0)
++			dstact = DSTACT_AUTO;
++
++		if (strcmp(destaction, "strip") == 0)
++			dstact = DSTACT_STRIP;
++
++		if (strcmp(destaction, "none") == 0)
++			dstact = DSTACT_NONE;
++	}
++
++	return 0;
++}
++
++module_init(init);
++module_exit(fini);
+diff -Nur linux-2.6.33.orig/net/netfilter/Kconfig linux-2.6.33/net/netfilter/Kconfig
+--- linux-2.6.33.orig/net/netfilter/Kconfig	2010-02-24 19:52:17.000000000 +0100
++++ linux-2.6.33/net/netfilter/Kconfig	2010-04-25 01:09:20.000000000 +0200
+@@ -268,6 +268,16 @@
+ 
+ 	  To compile it as a module, choose M here.  If unsure, say N.
+ 
++config NF_CONNTRACK_RTSP
++	tristate "RTSP protocol support"
++	depends on NF_CONNTRACK
++	help
++		Support the RTSP protocol.  This allows UDP transports to be setup
++		properly, including RTP and RDT.
++
++		If you want to compile it as a module, say 'M' here and read
++		Documentation/modules.txt.  If unsure, say 'Y'.
++
+ config NF_CT_NETLINK
+ 	tristate 'Connection tracking netlink interface'
+ 	select NETFILTER_NETLINK
+diff -Nur linux-2.6.33.orig/net/netfilter/Kconfig.orig linux-2.6.33/net/netfilter/Kconfig.orig
+--- linux-2.6.33.orig/net/netfilter/Kconfig.orig	1970-01-01 01:00:00.000000000 +0100
++++ linux-2.6.33/net/netfilter/Kconfig.orig	2010-02-24 19:52:17.000000000 +0100
+@@ -0,0 +1,937 @@
++menu "Core Netfilter Configuration"
++	depends on NET && INET && NETFILTER
++
++config NETFILTER_NETLINK
++	tristate
++
++config NETFILTER_NETLINK_QUEUE
++	tristate "Netfilter NFQUEUE over NFNETLINK interface"
++	depends on NETFILTER_ADVANCED
++	select NETFILTER_NETLINK
++	help
++	  If this option is enabled, the kernel will include support
++	  for queueing packets via NFNETLINK.
++	  
++config NETFILTER_NETLINK_LOG
++	tristate "Netfilter LOG over NFNETLINK interface"
++	default m if NETFILTER_ADVANCED=n
++	select NETFILTER_NETLINK
++	help
++	  If this option is enabled, the kernel will include support
++	  for logging packets via NFNETLINK.
++
++	  This obsoletes the existing ipt_ULOG and ebg_ulog mechanisms,
++	  and is also scheduled to replace the old syslog-based ipt_LOG
++	  and ip6t_LOG modules.
++
++config NF_CONNTRACK
++	tristate "Netfilter connection tracking support"
++	default m if NETFILTER_ADVANCED=n
++	help
++	  Connection tracking keeps a record of what packets have passed
++	  through your machine, in order to figure out how they are related
++	  into connections.
++
++	  This is required to do Masquerading or other kinds of Network
++	  Address Translation.  It can also be used to enhance packet
++	  filtering (see `Connection state match support' below).
++
++	  To compile it as a module, choose M here.  If unsure, say N.
++
++if NF_CONNTRACK
++
++config NF_CT_ACCT
++	bool "Connection tracking flow accounting"
++	depends on NETFILTER_ADVANCED
++	help
++	  If this option is enabled, the connection tracking code will
++	  keep per-flow packet and byte counters.
++
++	  Those counters can be used for flow-based accounting or the
++	  `connbytes' match.
++
++	  Please note that currently this option only sets a default state.
++	  You may change it at boot time with nf_conntrack.acct=0/1 kernel
++	  parameter or by loading the nf_conntrack module with acct=0/1.
++
++	  You may also disable/enable it on a running system with:
++	   sysctl net.netfilter.nf_conntrack_acct=0/1
++
++	  This option will be removed in 2.6.29.
++
++	  If unsure, say `N'.
++
++config NF_CONNTRACK_MARK
++	bool  'Connection mark tracking support'
++	depends on NETFILTER_ADVANCED
++	help
++	  This option enables support for connection marks, used by the
++	  `CONNMARK' target and `connmark' match. Similar to the mark value
++	  of packets, but this mark value is kept in the conntrack session
++	  instead of the individual packets.
++
++config NF_CONNTRACK_SECMARK
++	bool  'Connection tracking security mark support'
++	depends on NETWORK_SECMARK
++	default m if NETFILTER_ADVANCED=n
++	help
++	  This option enables security markings to be applied to
++	  connections.  Typically they are copied to connections from
++	  packets using the CONNSECMARK target and copied back from
++	  connections to packets with the same target, with the packets
++	  being originally labeled via SECMARK.
++
++	  If unsure, say 'N'.
++
++config NF_CONNTRACK_EVENTS
++	bool "Connection tracking events"
++	depends on NETFILTER_ADVANCED
++	help
++	  If this option is enabled, the connection tracking code will
++	  provide a notifier chain that can be used by other kernel code
++	  to get notified about changes in the connection tracking state.
++
++	  If unsure, say `N'.
++
++config NF_CT_PROTO_DCCP
++	tristate 'DCCP protocol connection tracking support (EXPERIMENTAL)'
++	depends on EXPERIMENTAL
++	depends on NETFILTER_ADVANCED
++	default IP_DCCP
++	help
++	  With this option enabled, the layer 3 independent connection
++	  tracking code will be able to do state tracking on DCCP connections.
++
++	  If unsure, say 'N'.
++
++config NF_CT_PROTO_GRE
++	tristate
++
++config NF_CT_PROTO_SCTP
++	tristate 'SCTP protocol connection tracking support (EXPERIMENTAL)'
++	depends on EXPERIMENTAL
++	depends on NETFILTER_ADVANCED
++	default IP_SCTP
++	help
++	  With this option enabled, the layer 3 independent connection
++	  tracking code will be able to do state tracking on SCTP connections.
++
++	  If you want to compile it as a module, say M here and read
++	  <file:Documentation/kbuild/modules.txt>.  If unsure, say `N'.
++
++config NF_CT_PROTO_UDPLITE
++	tristate 'UDP-Lite protocol connection tracking support'
++	depends on NETFILTER_ADVANCED
++	help
++	  With this option enabled, the layer 3 independent connection
++	  tracking code will be able to do state tracking on UDP-Lite
++	  connections.
++
++	  To compile it as a module, choose M here.  If unsure, say N.
++
++config NF_CONNTRACK_AMANDA
++	tristate "Amanda backup protocol support"
++	depends on NETFILTER_ADVANCED
++	select TEXTSEARCH
++	select TEXTSEARCH_KMP
++	help
++	  If you are running the Amanda backup package <http://www.amanda.org/>
++	  on this machine or machines that will be MASQUERADED through this
++	  machine, then you may want to enable this feature.  This allows the
++	  connection tracking and natting code to allow the sub-channels that
++	  Amanda requires for communication of the backup data, messages and
++	  index.
++
++	  To compile it as a module, choose M here.  If unsure, say N.
++
++config NF_CONNTRACK_FTP
++	tristate "FTP protocol support"
++	default m if NETFILTER_ADVANCED=n
++	help
++	  Tracking FTP connections is problematic: special helpers are
++	  required for tracking them, and doing masquerading and other forms
++	  of Network Address Translation on them.
++
++	  This is FTP support on Layer 3 independent connection tracking.
++	  Layer 3 independent connection tracking is experimental scheme
++	  which generalize ip_conntrack to support other layer 3 protocols.
++
++	  To compile it as a module, choose M here.  If unsure, say N.
++
++config NF_CONNTRACK_H323
++	tristate "H.323 protocol support"
++	depends on (IPV6 || IPV6=n)
++	depends on NETFILTER_ADVANCED
++	help
++	  H.323 is a VoIP signalling protocol from ITU-T. As one of the most
++	  important VoIP protocols, it is widely used by voice hardware and
++	  software including voice gateways, IP phones, Netmeeting, OpenPhone,
++	  Gnomemeeting, etc.
++
++	  With this module you can support H.323 on a connection tracking/NAT
++	  firewall.
++
++	  This module supports RAS, Fast Start, H.245 Tunnelling, Call
++	  Forwarding, RTP/RTCP and T.120 based audio, video, fax, chat,
++	  whiteboard, file transfer, etc. For more information, please
++	  visit http://nath323.sourceforge.net/.
++
++	  To compile it as a module, choose M here.  If unsure, say N.
++
++config NF_CONNTRACK_IRC
++	tristate "IRC protocol support"
++	default m if NETFILTER_ADVANCED=n
++	help
++	  There is a commonly-used extension to IRC called
++	  Direct Client-to-Client Protocol (DCC).  This enables users to send
++	  files to each other, and also chat to each other without the need
++	  of a server.  DCC Sending is used anywhere you send files over IRC,
++	  and DCC Chat is most commonly used by Eggdrop bots.  If you are
++	  using NAT, this extension will enable you to send files and initiate
++	  chats.  Note that you do NOT need this extension to get files or
++	  have others initiate chats, or everything else in IRC.
++
++	  To compile it as a module, choose M here.  If unsure, say N.</