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findnode(self) should return multiple peers #968
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Should we add a test for this?
} | ||
if !found { | ||
closest = append(closest, targetPid) | ||
closest = dht.betterPeersToQuery(pmes, from, dht.bucketSize) |
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dht.betterPeersToQuery
errors if the list contains self.
https://github.com/libp2p/go-libp2p-kad-dht/blob/master/dht.go#L765-L769
if clp == dht.self {
logger.Error("BUG betterPeersToQuery: attempted to return self! this shouldn't happen...")
return nil
}
// Dont send a peer back themselves
if clp == from {
continue
}
It also handles the case that we don't inform the peer about itself.
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This snippet handles the output of routingTable.NearestPeers
, which never contains itself.
The peer adds it own peer id, only if its own peer id is the target of the FIND_NODE
request at
Lines 263 to 285 in 7d6120f
// if looking for self... special case where we send it on CloserPeers. | |
targetPid := peer.ID(pmes.GetKey()) | |
closest = dht.betterPeersToQuery(pmes, from, dht.bucketSize) | |
// Never tell a peer about itself. | |
if targetPid != from { | |
// Add the target peer to the set of closest peers if | |
// not already present in our routing table. | |
// | |
// Later, when we lookup known addresses for all peers | |
// in this set, we'll prune this peer if we don't | |
// _actually_ know where it is. | |
found := false | |
for _, p := range closest { | |
if targetPid == p { | |
found = true | |
break | |
} | |
} | |
if !found { | |
closest = append(closest, targetPid) | |
} | |
} |
if !found { | ||
closest = append(closest, targetPid) | ||
} |
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Why do we do this? If the peerID isn't found, should we return it in findPeer?
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dht.betterPeersToQuery
never includes itself (nor from
) in the results.
Currently if A
sends FIND_NODE(B)
to B
, B
will reply [B]
, and we now want it to return [B, C, D, ...]
. In this case targetPid
is our own peer id, it wasn't returned by dht.betterPeersToQuery
, so we need to add it at this step.
We will be able to get rid of this when the response to FIND_NODE(self)
will be not include self
.
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But if the target node doesnt exist we will include it in the output, right?
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Peers without addresses are excluded from the response
Lines 292 to 301 in 7d6120f
closestinfos := pstore.PeerInfos(dht.peerstore, closest) | |
// possibly an over-allocation but this array is temporary anyways. | |
withAddresses := make([]peer.AddrInfo, 0, len(closestinfos)) | |
for _, pi := range closestinfos { | |
if len(pi.Addrs) > 0 { | |
withAddresses = append(withAddresses, pi) | |
} | |
} | |
resp.CloserPeers = pb.PeerInfosToPBPeers(dht.host.Network(), withAddresses) |
When receiving a kademlia
FIND_NODE
request for its own peer id, a go-libp2p-kad-dht node will respond with its own peer record only. According to libp2p kademlia spec, it should reply with thek
closest nodes.Depending on libp2p/specs#609, nodes shouldn't even include their own peer records in the response (already known to the requester). This will be implemented in a future PR.