Patchwork Fwd: LVS on local node

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Submitter Eric Dumazet
Date July 22, 2010, 9:46 a.m.
Message ID <1279791964.2467.12.camel@edumazet-laptop>
Download mbox | patch
Permalink /patch/59558/
State Not Applicable
Delegated to: David Miller
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Comments

Eric Dumazet - July 22, 2010, 9:46 a.m.
Le jeudi 22 juillet 2010 à 17:10 +0800, Changli Gao a écrit :

> 
> I think maybe REDIRECT is enough. If the public port is one of the
> real ports, you need to append "random" option to iptables target
> REDIRECT. If not, "REDIRECT --to-ports 1000-1007" is good enough, and
> the destination port will be selected in the round-robin manner.
> 

Yes, on 2.6.32, no RPS, so undocumented --random option is probably the
best we can offer. (random option was added in 2.6.22)

iptables -t nat -A PREROUTING -p tcp --dport 1234 -j REDIRECT --random --to-port 1000-1007

Here is a patch to add "random" help to REDIRECT iptables target

Thanks

[PATCH] extensions: REDIRECT: add random help

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
---



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Changli Gao - July 22, 2010, 9:52 a.m.
On Thu, Jul 22, 2010 at 5:46 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le jeudi 22 juillet 2010 à 17:10 +0800, Changli Gao a écrit :
>
>>
>> I think maybe REDIRECT is enough. If the public port is one of the
>> real ports, you need to append "random" option to iptables target
>> REDIRECT. If not, "REDIRECT --to-ports 1000-1007" is good enough, and
>> the destination port will be selected in the round-robin manner.
>>
>
> Yes, on 2.6.32, no RPS, so undocumented --random option is probably the
> best we can offer. (random option was added in 2.6.22)
>
> iptables -t nat -A PREROUTING -p tcp --dport 1234 -j REDIRECT --random --to-port 1000-1007
>
> Here is a patch to add "random" help to REDIRECT iptables target
>

FYI: the random option is documented in the manual page of iptables.

   REDIRECT
       This  target is only valid in the nat table, in the PREROUTING and OUT-
       PUT chains, and user-defined chains which are only  called  from  those
       chains.   It redirects the packet to the machine itself by changing the
       destination IP  to  the  primary  address  of  the  incoming  interface
       (locally-generated packets are mapped to the 127.0.0.1 address).

       --to-ports port[-port]
              This  specifies  a  destination  port  or range of ports to use:
              without this, the destination port is never  altered.   This  is
              only valid if the rule also specifies -p tcp or -p udp.

       --random
              If  option --random is used then port mapping will be randomized
              (kernel >= 2.6.22).
Eric Dumazet - July 22, 2010, 9:59 a.m.
Le jeudi 22 juillet 2010 à 17:52 +0800, Changli Gao a écrit :

> 
> FYI: the random option is documented in the manual page of iptables.
> 
>    REDIRECT
>        This  target is only valid in the nat table, in the PREROUTING and OUT-
>        PUT chains, and user-defined chains which are only  called  from  those
>        chains.   It redirects the packet to the machine itself by changing the
>        destination IP  to  the  primary  address  of  the  incoming  interface
>        (locally-generated packets are mapped to the 127.0.0.1 address).
> 
>        --to-ports port[-port]
>               This  specifies  a  destination  port  or range of ports to use:
>               without this, the destination port is never  altered.   This  is
>               only valid if the rule also specifies -p tcp or -p udp.
> 
>        --random
>               If  option --random is used then port mapping will be randomized
>               (kernel >= 2.6.22).
> 
> 

Note my patch has nothing to do with the man page, its already up2date.

I usually dont read the Fine manuals, do you ?

Try :

iptables -t nat -A PREROUTING -p tcp --dport 1234 -j REDIRECT --help

REDIRECT target options:
 --to-ports <port>[-<port>]
				Port (range) to map to.


You see [--random] is missing.



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Changli Gao - July 22, 2010, 10:06 a.m.
On Thu, Jul 22, 2010 at 5:59 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le jeudi 22 juillet 2010 à 17:52 +0800, Changli Gao a écrit :
>
>>
>> FYI: the random option is documented in the manual page of iptables.
>>
>>    REDIRECT
>>        This  target is only valid in the nat table, in the PREROUTING and OUT-
>>        PUT chains, and user-defined chains which are only  called  from  those
>>        chains.   It redirects the packet to the machine itself by changing the
>>        destination IP  to  the  primary  address  of  the  incoming  interface
>>        (locally-generated packets are mapped to the 127.0.0.1 address).
>>
>>        --to-ports port[-port]
>>               This  specifies  a  destination  port  or range of ports to use:
>>               without this, the destination port is never  altered.   This  is
>>               only valid if the rule also specifies -p tcp or -p udp.
>>
>>        --random
>>               If  option --random is used then port mapping will be randomized
>>               (kernel >= 2.6.22).
>>
>>
>
> Note my patch has nothing to do with the man page, its already up2date.
>
> I usually dont read the Fine manuals, do you ?

Yea. And I don't object your patch. so I add FYI. Thanks.

>
> Try :
>
> iptables -t nat -A PREROUTING -p tcp --dport 1234 -j REDIRECT --help
>
> REDIRECT target options:
>  --to-ports <port>[-<port>]
>                                Port (range) to map to.
>
>
> You see [--random] is missing.
>
>
Patrick McHardy - July 23, 2010, 10:54 a.m.
Am 22.07.2010 11:46, schrieb Eric Dumazet:
> [PATCH] extensions: REDIRECT: add random help
> 

Applied, thanks Eric.
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Patch

diff --git a/extensions/libipt_REDIRECT.c b/extensions/libipt_REDIRECT.c
index 3dfcadf..324d0eb 100644
--- a/extensions/libipt_REDIRECT.c
+++ b/extensions/libipt_REDIRECT.c
@@ -17,7 +17,8 @@  static void REDIRECT_help(void)
 	printf(
 "REDIRECT target options:\n"
 " --to-ports <port>[-<port>]\n"
-"				Port (range) to map to.\n");
+"				Port (range) to map to.\n"
+" [--random]\n");
 }
 
 static const struct option REDIRECT_opts[] = {