Re: ip_conntrack_ftp messages

[Patrick McHardy <kaber@trash.net>]

Rusty Russell wrote:
> On Monday 24 November 2008 22:58:09 Patrick McHardy wrote:
>> Rusty Russell wrote:
>>> 		if (net_ratelimit())
>>> 			printk("conntrack_ftp: partial %s %u+%u\n",
>>> 			       search[dir][i].pattern,
>>> 			       ntohl(th->seq), datalen);
>> Its strange that FTP is apparently working since we drop those packets.
>> I'm not sure about downgrading that message, its there to inform the
>> user of an exceptional action (dropping of packets within conntrack).
> 
> Actually, we drop the packets *so* it will work.  The idea is that they'll 
> coalesce and send the whole packet next time.

I see. The only case in which I triggered it so far was when sending
incomplete PORT commands using telnet, so I missed this important
fact :)

> If not, well, they don't get any more packes through, but without connection 
> tracking the other connections wouldn't work anyway (if the conntrack is being 
> used for NAT or filtering).
> 
> IIRC wu-ftpd used to trigger this (multiple write syscalls for the ip address 
> and nagle sometimes hit in the middle; go figure).

Thanks for the explanation. I'll queue up a patch for 2.6.29 to change
it to pr_debug().