Question about TC functionality

Question about TC functionality

[Tomasz W]

Good morning,

I am writing software that implements DPI to shape traffic flow. I have already done packet sniffing and recognition (e.g. ICMP, Skype, HTTP, etc). However I would like to implement HTB for just those packets that I select, so I can "slow" or "speed" them up. I know that tc can do that, but I can't find how to do that basing on packets.

Kind Regards,
Tomasz

Re: Question about TC functionality

[Erik Auerswald]

Hello Tomasz,

On Mon, Aug 17, 2020 at 06:01:42AM +0200, Tomasz W wrote:
> I am writing software that implements DPI to shape traffic flow. I have
> already done packet sniffing and recognition (e.g. ICMP, Skype, HTTP,
> etc). However I would like to implement HTB for just those packets
> that I select, so I can "slow" or "speed" them up. I know that tc can
> do that, but I can't find how to do that basing on packets.

You would probably need to somehow mark the packets, and then let "tc"
match based on that mark.  Otherwise you would need to implement the
DPI inside tc.

You could look into seeting the "fwmark" based on DPI, and then have tc
match on that.

Or you could look into setting a DSCP value based on DPI, and then match
on that, using, e.g., the u32 match of tc.

See, e.g., https://lartc.org/howto/lartc.adv-filter.html for additional
info.

HTH,
Erik

Re: Question about TC functionality

[Grant Taylor]

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On 8/16/20 10:01 PM, Tomasz W wrote:
> Good morning,

Hi,

> I am writing software that implements DPI to shape traffic flow. I 
> have already done packet sniffing and recognition (e.g. ICMP, Skype, 
> HTTP, etc). However I would like to implement HTB for just those 
> packets that I select, so I can "slow" or "speed" them up. I know 
> that tc can do that, but I can't find how to do that basing on packets.

In addition to what Erik suggested, you might be able to apply routes 
via iptables such that traffic goes out different (virtual) interfaces 
and then apply generic tc QoS as desired on the different (virtual) 
interfaces.



-- 
Grant. . . .
unix || die


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