From: Helge Deller <deller@gmx•de>
To: Cong Wang <amwang@redhat•com>
Cc: Octavian Purdila <octavian.purdila@intel•com>,
netdev@vger•kernel.org, David Miller <davem@davemloft•net>,
Andrew Morton <akpm@linux-foundation•org>,
"Eric W. Biederman" <ebiederm@xmission•com>,
Frank Danapfel <fdanapfe@redhat•com>,
Laszlo Ersek <lersek@redhat•com>,
shemminger@vyatta•com
Subject: Re: [RFC] API to modify /proc/sys/net/ipv4/ip_local_reserved_ports
Date: Tue, 10 Apr 2012 23:04:47 +0200 [thread overview]
Message-ID: <4F84A06F.3090808@gmx.de> (raw)
In-Reply-To: <1333960981.414.24.camel@cr0>
On 04/09/2012 10:43 AM, Cong Wang wrote:
> On Wed, 2012-04-04 at 22:24 +0200, Helge Deller wrote:
>> I would like to follow up on my last patch series to be able to modify
>> the contents of the /proc/sys/net/ipv4/ip_local_reserved_ports port list
>> from userspace.
>>
>> My last patch (https://lkml.org/lkml/2012/3/10/187) was based on
>> modifications to the proc interface, which - based on the feedback here
>> on the list - seemed to not be the right way to go (although I personally
>> still like the idea very much :-)).
>>
>> Anyway, with this RFC I would like to get feedback about a new proposed
>> API and attached kernel patch.
>>
>> The idea is to introduce a new<optname> value for get/setsockopt()
>> named SO_RESERVED_PORTS to get/set the ip_local_reserved_ports
>> bitmap via standard get/setsockopt() syscalls.
>> As far as I understand this seems to be similiar to how iptables works.
>>
>> An untested kernel patch for review and feedback is attached below.
>>
>> In userspace it then would be possible to write a new tool or to extend
>> for example the "ip" tool to accept commands like:
>> $> ip reserved_ports add 100-2000
>> $> ip reserved_ports remove 50-60
>> $> ip reserved_ports list (to show current reserved port list)
>>
>> This userspace tool could then read the port bitmap from kernel via
>> a) socket(PF_INET, SOCK_RAW, IPPROTO_RAW)
>> b) getsockopt(3, SOL_SOCKET, SO_RESERVED_PORTS,<bitmaplist>)
>> and write back the results after modification via
>> c) setsockopt(3, SOL_SOCKET, SO_RESERVED_PORTS,<bitmaplist>)
>>
>> Would that be an acceptable solution?
> Hmm, it is indeed that bitmap fits for syscall rather than /proc file.
>
> But it seems that using getsockopt()/setsockopt() makes it like it is a
> per-socket setting, actually it is a system-wide setting.
Yes, that's the reason why I used SOL_SOCKET which configures at least
a few system-wide settings too.
> So I am
> wondering if exporting a binary /proc file for this is a better
> solution.
Yeah - that's another solution, but (65536 ports)/(8 bits per byte) = 8
KByte, so we
may again hit the 4k limit of /proc (unless you do binary reads which should
be done with a binary /proc-entry anyway).
Again, I'm open to develop any kind of solution which would get an OK here.
Helge
next prev parent reply other threads:[~2012-04-10 21:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4F5BE563.9050506@gmx.de>
2012-03-13 20:33 ` [PATCH] enhance usability of /proc/sys/net/ipv4/ip_local_reserved_ports (v2) Helge Deller
2012-03-14 7:43 ` Cong Wang
2012-03-14 22:06 ` Helge Deller
2012-03-14 22:20 ` Stephen Hemminger
2012-03-14 22:14 ` [PATCH] enhance usability of /proc/sys/net/ipv4/ip_local_reserved_ports (v3) Helge Deller
2012-03-14 22:34 ` Eric W. Biederman
2012-03-15 23:35 ` Helge Deller
2012-04-04 20:24 ` [RFC] API to modify /proc/sys/net/ipv4/ip_local_reserved_ports Helge Deller
2012-04-09 8:43 ` Cong Wang
2012-04-10 21:04 ` Helge Deller [this message]
2012-04-10 22:13 ` Eric W. Biederman
2012-05-17 21:18 ` Helge Deller
2012-05-17 21:22 ` Stephen Hemminger
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