git-annex/Assistant/Pairing.hs
Joey Hess 7e7e765cba Improve local pairing behavior when two computers both try to start the pairing process separately.
I was able to reproduce something very like this bug by starting
pairing separately on both computers under poor network conditions (ie,
weak wifi on my front porch). Neither computer showed an alert for the
PairReq messages it was seeing (intermittently) from the other.

So, I've made a new PairReq message that has not been seen before
always make the alert pop up, even if the assistant thinks it is
in the middle of its own pairing process (or even another pairing
process with a different box on the LAN).

(This shouldn't cause a rogue PairAck to disrupt a pairing process part
way through.)
2013-11-02 15:10:29 -04:00

92 lines
2.6 KiB
Haskell

{- git-annex assistant repo pairing, core data types
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE CPP #-}
module Assistant.Pairing where
import Common.Annex
import Utility.Verifiable
import Assistant.Ssh
import Control.Concurrent
import Network.Socket
import Data.Char
import qualified Data.Text as T
data PairStage
{- "I'll pair with anybody who shares the secret that can be used
- to verify this request." -}
= PairReq
{- "I've verified your request, and you can verify this to see
- that I know the secret. I set up your ssh key already.
- Here's mine for you to set up." -}
| PairAck
{- "I saw your PairAck; you can stop sending them." -}
| PairDone
deriving (Eq, Read, Show, Ord, Enum)
newtype PairMsg = PairMsg (Verifiable (PairStage, PairData, SomeAddr))
deriving (Eq, Read, Show)
verifiedPairMsg :: PairMsg -> PairingInProgress -> Bool
verifiedPairMsg (PairMsg m) pip = verify m $ inProgressSecret pip
fromPairMsg :: PairMsg -> Verifiable (PairStage, PairData, SomeAddr)
fromPairMsg (PairMsg m) = m
pairMsgStage :: PairMsg -> PairStage
pairMsgStage (PairMsg (Verifiable (s, _, _) _)) = s
pairMsgData :: PairMsg -> PairData
pairMsgData (PairMsg (Verifiable (_, d, _) _)) = d
pairMsgAddr :: PairMsg -> SomeAddr
pairMsgAddr (PairMsg (Verifiable (_, _, a) _)) = a
data PairData = PairData
-- uname -n output, not a full domain name
{ remoteHostName :: Maybe HostName
, remoteUserName :: UserName
, remoteDirectory :: FilePath
, remoteSshPubKey :: SshPubKey
, pairUUID :: UUID
}
deriving (Eq, Read, Show)
type UserName = String
{- A pairing that is in progress has a secret, a thread that is
- broadcasting pairing messages, and a SshKeyPair that has not yet been
- set up on disk. -}
data PairingInProgress = PairingInProgress
{ inProgressSecret :: Secret
, inProgressThreadId :: Maybe ThreadId
, inProgressSshKeyPair :: SshKeyPair
, inProgressPairData :: PairData
, inProgressPairStage :: PairStage
}
deriving (Show)
data SomeAddr = IPv4Addr HostAddress
{- My Android build of the Network library does not currently have IPV6
- support. -}
#ifndef __ANDROID__
| IPv6Addr HostAddress6
#endif
deriving (Ord, Eq, Read, Show)
{- This contains the whole secret, just lightly obfuscated to make it not
- too obvious. It's only displayed in the user's web browser. -}
newtype SecretReminder = SecretReminder [Int]
deriving (Show, Eq, Ord, Read)
toSecretReminder :: T.Text -> SecretReminder
toSecretReminder = SecretReminder . map ord . T.unpack
fromSecretReminder :: SecretReminder -> T.Text
fromSecretReminder (SecretReminder s) = T.pack $ map chr s