linux-kernel - Re: [RFC Patch] net: reserve ports for applications using fixed port numbers

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Date:	Thu, 04 Feb 2010 11:23:38 +0800
From:	Cong Wang <amwang@...hat.com>
To:	Octavian Purdila <opurdila@...acom.com>
CC:	linux-kernel@...r.kernel.org,
	Eric Dumazet <eric.dumazet@...il.com>,
	linux-rdma@...r.kernel.org, netdev@...r.kernel.org,
	Neil Horman <nhorman@...driver.com>,
	linux-sctp@...r.kernel.org, David Miller <davem@...emloft.net>
Subject: Re: [RFC Patch] net: reserve ports for applications using fixed port
 numbers

Octavian Purdila wrote:
> On Wednesday 03 February 2010 06:30:07 you wrote:
> 
>> This patch introduces /proc/sys/net/ipv4/ip_local_reserved_ports,
>> it can be used like ip_local_port_range, but this is used to
>> reserve ports for third-party applications which use fixed
>> port numbers within ip_local_port_range.
>>
>> This only affects the applications which call socket functions
>> like bind(2) with port number 0, to prevent the kernel getting the ports
>> within the specified range for them. For applications which use fixed
>> port number, it will have no effects.
> 
> It also affects the case where applications do connect, without previously 
> doing bind, right?


Yeah, I forgot to mention this, sorry.

> 
>> Any comments are welcome.
> 
> I think it might be useful to allow setting individual ports as reserved, not 
> only ranges, for example by using a bitmap. 
> 

This is a good idea, but I am not sure if this will be overkill? :-/
Also, using bitmap is not friendly to sysctl interface, I am afraid.


Thanks!
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