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Change default response to QueryID for unjoined nodes

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reason: allow unjoined nodes to find bootstrap node in local cache,
while always advertising itself to incoming requests for bootstrapping.
This commit is contained in:
Trolli Schmittlauch 2020-07-02 00:54:14 +02:00
parent 8d349212b4
commit f6481996d7
2 changed files with 23 additions and 5 deletions
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10
src/Hash2Pub/DHTProtocol.hs
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@ -90,7 +90,9 @@ import Debug.Trace (trace)
queryLocalCache :: LocalNodeState -> NodeCache -> Int -> NodeID -> QueryResponse
queryLocalCache ownState nCache lBestNodes targetID
-- as target ID falls between own ID and first predecessor, it is handled by this node
| targetID `isInOwnResponsibilitySlice` ownState = FOUND . toRemoteNodeState $ ownState
-- This only makes sense if the node is part of the DHT by having joined.
-- A default answer to nodes querying an unjoined node is provided by 'respondQueryID'.
| isJoined ownState && targetID `isInOwnResponsibilitySlice` ownState = FOUND . toRemoteNodeState $ ownState
-- my interpretation: the "l best next hops" are the l-1 closest preceding nodes and
-- the closest succeeding node (like with the p initiated parallel queries
| otherwise = FORWARD $ closestSuccessor `Set.union` closestCachePredecessors (lBestNodes-1) targetID nCache
@ -296,7 +298,11 @@ respondQueryID nsSTM msgSet = do
cache <- readTVar $ nodeCacheSTM nsSnap
let
responsePayload = QueryIDResponsePayload {
queryResult = queryLocalCache nsSnap cache (fromIntegral $ queryLBestNodes senderPayload') (queryTargetID senderPayload')
queryResult = if isJoined nsSnap
then queryLocalCache nsSnap cache (fromIntegral $ queryLBestNodes senderPayload') (queryTargetID senderPayload')
-- if not joined yet, attract responsibility for
-- all keys to make bootstrapping possible
else FOUND (toRemoteNodeState nsSnap)
}
queryResponseMsg = Response {
requestID = requestID aRequestPart

18
test/FediChordSpec.hs
View file

@ -132,10 +132,11 @@ spec = do
cacheWith2Entries :: NodeCache
cacheWith2Entries = addCacheEntryPure 10 (RemoteCacheEntry node5 10) (addCacheEntryPure 10 (RemoteCacheEntry node2 10) emptyCache)
cacheWith4Entries = addCacheEntryPure 10 (RemoteCacheEntry node3 10) (addCacheEntryPure 10 (RemoteCacheEntry node4 10) cacheWith2Entries)
it "nodes not joined provide the default answer FOUND" $ do
it "unjoined nodes should never return themselfs" $ do
exampleLocalNodeAsRemote <- toRemoteNodeState <$> exampleLocalNode
queryLocalCache <$> exampleLocalNode <*> pure emptyCache <*> pure 3 <*> pure (toNodeID 2^(9::Integer)+5) `shouldReturn` FOUND exampleLocalNodeAsRemote
queryLocalCache <$> exampleLocalNode <*> pure cacheWith4Entries <*> pure 1 <*> pure (toNodeID 2342) `shouldReturn` FOUND exampleLocalNodeAsRemote
queryLocalCache <$> exampleLocalNode <*> pure emptyCache <*> pure 3 <*> pure (toNodeID 2^(9::Integer)+5) `shouldReturn` FORWARD Set.empty
(FORWARD fwSet) <- queryLocalCache <$> exampleLocalNode <*> pure cacheWith4Entries <*> pure 1 <*> (getNid <$> exampleLocalNode)
remoteNode (head $ Set.elems fwSet) `shouldBe` node4
it "joined nodes do not fall back to the default" $
queryLocalCache <$> node1 <*> pure emptyCache <*> pure 1 <*> pure (toNodeID 3) `shouldReturn` FORWARD Set.empty
it "works on a cache with less entries than needed" $ do
@ -265,6 +266,17 @@ spec = do
let startAt5 = serialiseMessage 600 (largeMessage {part = 5})
Map.lookup 1 startAt5 `shouldBe` Nothing
part <$> (deserialiseMessage . fromJust) (Map.lookup 5 startAt5) `shouldBe` Right 5
describe "join cache lookup" $
it "A bootstrap cache initialised with just one node returns that one." $ do
let
bootstrapNid = toNodeID 34804191837661041451755206127000721433747285589603756490902196113256157045194
bootstrapNode = setNid bootstrapNid exampleNodeState
bootstrapCache = addCacheEntryPure 10 (RemoteCacheEntry bootstrapNode 19) initCache
ownId = toNodeID 34804191837661041451755206127000721433707928516052624394829818586723613390165
ownNode <- setNid ownId <$> exampleLocalNode
let (FORWARD qResult) = queryLocalCache ownNode bootstrapCache 2 ownId
remoteNode (head $ Set.elems qResult) `shouldBe` bootstrapNode
-- some example data