Discovery: Node responses with different public key

[chfast]

It happens quite often that a pinged node can response with a pong but with different public key.

DEBUG 01-14 11:16:58 p2p  discov Ping to ##967b8992…@3.86.38.233 UDP 30303 TCP 30303
DEBUG 01-14 11:16:59 p2p  discov Pong from ##3d825603…@3.86.38.233:30303
DEBUG 01-14 11:16:59 p2p  discov Unexpected PONG from 3.86.38.233:30303

[halfalicious]

I wonder if the pinged node is an aleth node running on Windows...by default a Windows aleth node will generate a new pub/priv key pair on each launch since bug #5370 prevents it from saving its network config on shutdown.

[gumb0]

What we should do I think is map EndpointPinged->NodeValidation instead of NodeID->NodeValidation in m_sentPings (and add NodeID to NodeValidation)

Then Pong handler will have

if nodeId == oldNodeId
  // this part alredy exists
  update lastPongReceivedTime
  if validation has replacementNodeId
    dropNode(replacement) 
else
   addNode(nodeId, Known) // add it with current time as lastPongReceivedTime

This way in case NodeID changed the old one will be evicted by timeout and replaced in the node table with replacementNodeId