5730a43703 test: Add functional test for AddrFetch connections (Martin Zumsande)
c34ad3309f net, rpc: Enable AddrFetch connections for functional testing (Martin Zumsande)
533500d907 p2p: Add timeout for AddrFetch peers (Martin Zumsande)
b6c5d1e450 p2p: AddrFetch - don't disconnect on self-announcements (Martin Zumsande)
Pull request description:
AddrFetch connections (old name: oneshots) are intended to be short-lived connections on which we ask a peer for addresses via `getaddr` and disconnect after receiving them.
This is done by disconnecting after receiving the first `addr`. However, it is no longer working as intended, because nowadays, the first `addr` a typical bitcoin core node sends is its self-announcement.
So we'll disconnect before the peer gets a chance to answer our `getaddr`.
I checked that this affects both `-seednode` peers specified manually, and DNS seeds when AddrFetch is used as a fallback if DNS doesn't work for us.
The current behavior of getting peers via AddrFetch when starting with an empty addrman would be to connect to the peer, receive its self-announcement and add it to addrman, disconnect, reconnect to the same peer again as a full outbound (no other addresses in addrman) and then receive more `addr`. This is silly and not in line with AddrFetch peer being intended to be short-lived peers.
Fix this by only disconnecting after receiving an `addr` message of size > 1.
[Edit] As per review discussion, this PR now also adds a timeout after which we disconnect if we haven't received any suitable `addr`, and a functional test.
ACKs for top commit:
amitiuttarwar:
reACK 5730a43703
naumenkogs:
ACK 5730a43703
jnewbery:
ACK 5730a43703
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e4487fd5bb