Re: [Monotone-devel] what does this mean? (bad HMAC error and discarding revision cert packets...)

[Nathaniel Smith]

On Tue, Jul 19, 2005 at 03:25:00PM +0200, Marcel van der Boom wrote:
> On a pull:
> 
> mt -d modules.db pull davinci:15000 \*
> .
> .
> monotone:    25.3M |      1.9M |    19650 |    4712 |         2659
> monotone: warning: protocol error while processing peer davinci: 
> 15000: 'bad HMAC 22bf02d9b4a74a1fc572b1a064463dbfc6b32af6 vs.  
> 843d264d4c1bf45664a233064baa220a48675575'
> monotone: warning: discarding revision cert packet  
> 001aebe1090ad383d698bb5af24c7a4cea74cfd0 with unmet dependencies
> .
> . <repeats of that line with different hashes>
> .

The HMAC is an integrity check, that makes sure bytes were transmitted
accurately, and by the person you expected to have transmitting them.
'bad HMAC' means either:
  -- some bytes got corrupted on the wire, or
  -- there's some new bug in netsync that's causing it to lose
     protocol synchronization
Hard to say which without more information.  (Is the problem
reproducible?)

In either case, it caused monotone to kill the connection and give up.

The "discarding revision cert packet" stuff means that, after the
connection dropped, monotone threw away a bunch of certs it had
already received, because by the time the connection dropped, it
hadn't yet received the revisions they went with.  It's totally
expected, given an HMAC error.

-- Nathaniel

-- 
Damn the Solar System.  Bad light; planets too distant; pestered with
comets; feeble contrivance; could make a better one myself.
  -- Lord Jeffrey