Re: bug(s) in ipvs-0.2.4

To: Radu-Adrian Feurdean <raf@xxxxxxxx>
Subject: Re: bug(s) in ipvs-0.2.4
Cc: Wensong Zhang <wensong@xxxxxxxxxxxx>, lvs-users@xxxxxxxxxxxxxxxxxxxxxx
From: Julian Anastasov <ja@xxxxxx>
Date: Thu, 22 Feb 2001 13:57:11 +0200 (EET)

On Thu, 22 Feb 2001, Radu-Adrian Feurdean wrote:

> Hi,
> While trying to implement a load-balancer based on ipvs-0.2.4 I found some
> bugs in the code. The testing environment used is: kernel 2.4.2-pre[34] for
> load balancer and NAT as load-balancing method
> 1. TCP state transition diagrams in ipvs/ip_vs_conn.c have initial states in
> the wrong order (according to ipvs/ip_vs.h). The problem is that
> IP_VS_S_SYNACK should be the 5th state in the table and it is the last. I have
> observed this because a close request initiated by the client leaves the
> connection open on the director. Here are the debug messages:
> IPVS: Schedule fwd:M s:NONE c: v: 
> d: flg:140 cnt:2
> IPVS: TCP input  [S...]> state: 
> NONE->SYN_RECV cnt:2
> IPVS: TCP input  [..A.]> state: 
> IPVS: TCP input  [.FA.]> state: 
> IPVS: TCP output  [..A.]> state: 
> IPVS: TCP output  [.FA.]> state: 
> IPVS: TCP input  [..A.]> state: 
> You can see that the last 2 lines are not exactly a correct behaviour.
> 2. The ftp module does not work for passive mode (it doesn't work at all but
> the active mode can be managed using standard masquerading). The FTP handling
> code does not properly deal with the new connection (the director doesn't
> handle it at all).
> There is an attached patch that solves the two above-mentioned problems. I'm
> not sure that the second problem is resolved the right way, but at least it
> works.

        Ignoring the fact your patch is broken the (1) is a _REAL_ bug.
We must move and insert the SA column before FW. It seems the
SA value is different from Linux 2.2 but the same transition table is
used :)

        For (2) we have to analyze where is really the problem. Personally,
I didn't tried the ftp module from long time ago.

        Thanks for this report.

> Bye
> Radu-Adrian Feurdean
> mailto: raf@xxxxxxxx
> -------------------------------------------------------------------
> "If the night is silent enough you can hear a Windows NT rebooting"


Julian Anastasov <ja@xxxxxx>

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