trying to revive rtsp

trying to revive rtsp

[Mickael Marchand]

Hi,

I am really a newbie to the netfilter coding world, so please forgive
any stupid questions :)

I have mostly ported the old rtsp conntrack+nat code to recent 2.6
kernels, compiles and loads fine into the kernel,
but I have some problems to make it work now :)

the initial TCP connexion to the RTSP server:554 is correctly detected
and the expectation packet seems to be properly setup :
cat /proc/net/ip_conntrack_expect
255 proto=17 src=212.27.38.253 dst=10.0.0.2 sport=0 dport=33302

212.27.38.253 is the RTSP server, 10.0.0.2 is the client, 10.0.0.1 is
the netfilter box.

so once the TCP connexion has been established, we expect a UDP stream
from the server going to the client port 33302.

my problem is that the expected packet does not get through the
netfilter box, I can see the UDP stream coming from the RTSP server and
going to my netfilter box,
the expectation packet seems to get removed of
/proc/net/ip_conntrack_expect as well (so basically it looks all good)
but the netfilter box does not forward packets to 10.0.0.2.
so it looks like a NAT problem to me, maybe the UDP packets are not
getting NAT-ed back to the client.

my first question would be :
is it expected to see 10.0.0.2 in the expected paquet ?
should not it be my external IP instead ?

any tips in what direction I could look ? :)

thanks for any help

Cheers,
Mik
(Please CC-me in answers :)

trying to revive rtsp

[Mickael Marchand]

Hi,

I am really a newbie to the netfilter coding world, so please forgive
any stupid questions :)

I have mostly ported the old rtsp conntrack+nat code to recent 2.6
kernels, compiles and loads fine into the kernel,
but I have some problems to make it work now :)

the initial TCP connexion to the RTSP server:554 is correctly detected
and the expectation packet seems to be properly setup :
cat /proc/net/ip_conntrack_expect
255 proto=17 src=212.27.38.253 dst=10.0.0.2 sport=0 dport=33302

212.27.38.253 is the RTSP server, 10.0.0.2 is the client, 10.0.0.1 is
the netfilter box.

so once the TCP connexion has been established, we expect a UDP stream
from the server going to the client port 33302.

my problem is that the expected packet does not get through the
netfilter box, I can see the UDP stream coming from the RTSP server and
going to my netfilter box,
the expectation packet seems to get removed of
/proc/net/ip_conntrack_expect as well (so basically it looks all good)
but the netfilter box does not forward packets to 10.0.0.2.
so it looks like a NAT problem to me, maybe the UDP packets are not
getting NAT-ed back to the client.

my first question would be :
is it expected to see 10.0.0.2 in the expected paquet ?
should not it be my external IP instead ?

any tips in what direction I could look ? :)

thanks for any help

Cheers,
Mik
(Please CC-me in answers :)

(posted a second time since the first one did not reach the lists
apparently, sorry if you receive it twice ...)

Re: trying to revive rtsp

[Patrick McHardy]

Mickael Marchand wrote:
> Hi,
> 
> I am really a newbie to the netfilter coding world, so please forgive
> any stupid questions :)
> 
> I have mostly ported the old rtsp conntrack+nat code to recent 2.6
> kernels, compiles and loads fine into the kernel,
> but I have some problems to make it work now :)
> 
> the initial TCP connexion to the RTSP server:554 is correctly detected
> and the expectation packet seems to be properly setup :
> cat /proc/net/ip_conntrack_expect
> 255 proto=17 src=212.27.38.253 dst=10.0.0.2 sport=0 dport=33302
> 
> 212.27.38.253 is the RTSP server, 10.0.0.2 is the client, 10.0.0.1 is
> the netfilter box.
> 
> so once the TCP connexion has been established, we expect a UDP stream
> from the server going to the client port 33302.
> 
> my problem is that the expected packet does not get through the
> netfilter box, I can see the UDP stream coming from the RTSP server and
> going to my netfilter box,
> the expectation packet seems to get removed of
> /proc/net/ip_conntrack_expect as well (so basically it looks all good)
> but the netfilter box does not forward packets to 10.0.0.2.
> so it looks like a NAT problem to me, maybe the UDP packets are not
> getting NAT-ed back to the client.
> 
> my first question would be :
> is it expected to see 10.0.0.2 in the expected paquet ?
> should not it be my external IP instead ?
> 
> any tips in what direction I could look ? :)

Probably something related to the expect API changes and/or missing
initializations. Compare your helper with other helpers and make sure
you initialize all fields of struct ip_conntrack_expect properly.

Re: trying to revive rtsp

[Punky]

Hi Mickael,

I am doing the same thing - try to port rtsp to 2.6.15.  And I
encountered problem in porting rtsp nat code.  You can refer to mms
and talk conntrack/nat code to see how API are changed.  Moreover, I
used svn to check how codes are change in each revision as well.

Moreover, if you have any news on the porting, please let me know.

Regards,
Punky

On 2/19/06, Mickael Marchand <marchand@kde.org> wrote:
> Hi,
>
> I am really a newbie to the netfilter coding world, so please forgive
> any stupid questions :)
>
> I have mostly ported the old rtsp conntrack+nat code to recent 2.6
> kernels, compiles and loads fine into the kernel,
> but I have some problems to make it work now :)
>
> the initial TCP connexion to the RTSP server:554 is correctly detected
> and the expectation packet seems to be properly setup :
> cat /proc/net/ip_conntrack_expect
> 255 proto=17 src=212.27.38.253 dst=10.0.0.2 sport=0 dport=33302
>
> 212.27.38.253 is the RTSP server, 10.0.0.2 is the client, 10.0.0.1 is
> the netfilter box.
>
> so once the TCP connexion has been established, we expect a UDP stream
> from the server going to the client port 33302.
>
> my problem is that the expected packet does not get through the
> netfilter box, I can see the UDP stream coming from the RTSP server and
> going to my netfilter box,
> the expectation packet seems to get removed of
> /proc/net/ip_conntrack_expect as well (so basically it looks all good)
> but the netfilter box does not forward packets to 10.0.0.2.
> so it looks like a NAT problem to me, maybe the UDP packets are not
> getting NAT-ed back to the client.
>
> my first question would be :
> is it expected to see 10.0.0.2 in the expected paquet ?
> should not it be my external IP instead ?
>
> any tips in what direction I could look ? :)
>
> thanks for any help
>
> Cheers,
> Mik
> (Please CC-me in answers :)
>
>


--
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Regards,
Punky
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Technology + Lifestyle
(http://www.punknix.com)

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