[freenet-dev] [freenet-cvs] r16744 - trunk/freenet/src/freenet/node

[Robert Hailey]

On Dec 21, 2007, at 7:28 AM, Matthew Toseland wrote:

> Is this wise? It usually indicates a moderately serious problem, if  
> there are
> many of them there may be e.g. a link layer bug ... ? I suppose  
> eventually
> we'll get a PacketSequenceException in that case, so maybe NORMAL?  
> These
> could also indicate deliberate replays, though I don't see much  
> point, and we
> may not want to log them if so..

Before decreasing it so, I would get this message very frequently. It  
may be a local router duplicating packets (which doesn't know the best  
route?).

IIRC, the deal with UDP is that (1) you may not get the sent packet,  
(2) you may not get them FIFO, and (3) you might not get only one of  
them.

So far as deliberate replays... seeing that the very next statement we  
ignore the packet, you are right: the only possible DoS would involve  
excessive logging, and no log statement at all would be better.

--
Robert Hailey


> On Thursday 20 December 2007 16:25, robert at freenetproject.org wrote:
>> Author: robert
>> Date: 2007-12-20 16:25:53 +0000 (Thu, 20 Dec 2007)
>> New Revision: 16744
>>
>> Modified:
>>   trunk/freenet/src/freenet/node/FNPPacketMangler.java
>> Log:
>> demote 'received packet twice' message
>> [...]