[tor-relays] Handshake flood now on NTor

[Jobiwan Kenobi]

Hi,

For about 15 hours straight, my relay was being hammered by 
connections/handshakes. 

I see lots of these: 

Sep 02 01:03:02.000 [warn] Your computer is too slow to handle this many circuit creation requests! Please consider using the MaxAdvertisedBandwidth config option or choosing a more restricted exit policy. [70638 similar message(s) suppressed in last 60 seconds]

Numbers vary between 30000 and 80000 per 60 seconds.

Also the occasional clock jump message and other performance related 
messages, and of course, _lots_ of unsuccessful handshakes:

Sep 01 22:31:26.000 [notice] Circuit handshake stats since last time: 5038/5038 TAP, 17771/17773 NTor.
Sep 02 04:31:26.000 [notice] Circuit handshake stats since last time: 3100/3484 TAP, 465565/5417818 NTor.
Sep 02 10:31:26.000 [notice] Circuit handshake stats since last time: 3139/4249 TAP, 679872/8244698 NTor.
Sep 02 16:31:26.000 [notice] Circuit handshake stats since last time: 3884/5294 TAP, 502835/10443735 NTor.

It is a low spec machine. 

I've been through episodes like this before, but this time it's 
different:

- They are NTor handshakes, where before they would be TAP 
  handshakes.
- The amount of up and down traffic is pretty balanced, where before 
  I would get much more down than up during these floods.
- In case it matters: I am now running 0.2.4.23, before I was on 
  0.2.4.18-RC


It stopped about 4 hours ago. Running normal now.

-Job