This fixes the remaining Hive discv5/FindnodeResults failures in the
cmd/devp2p/internal/v5test fixture.
The issue was in the simulator-side bystander behavior, not in
production discovery logic. The existing fixture could get bystanders
inserted into the remote table, but under current geth behavior they
were not stable enough to remain valid FINDNODE results. In
particular, the fixture still had a few protocol/behavior mismatches:
- incomplete WHOAREYOU recovery
- replies not consistently following the UDP envelope source
- incorrect endpoint echoing in PONG
- fixture-originated PING using the wrong ENR sequence
- bystanders answering background FINDNODE with empty NODES
That last point was important because current lookup accounting can
treat repeatedly unhelpful FINDNODE interactions as failures. As a
result, a bystander could become live via PING/PONG and still later be
dropped from the table before the final FindnodeResults assertion.
This change updates the fixture so that bystanders behave more like
stable discv5 peers:
- perform one explicit initial handshake, then switch to passive response handling
- resend the exact challenged packet when handling WHOAREYOU
- reply to the actual UDP packet source and mirror that source in PONG.ToIP / PONG.ToPort
- use the bystander’s own ENR sequence in fixture-originated PING
- prefill each bystander with the bystander ENR set and answer FINDNODE from that set
The result is that the fixture now forms a small self-consistent lookup
environment instead of a set of peers that are live but systematically
poor lookup participants.
This changes the challenge resend logic again to use the existing
`ChallengeData` field of `v5wire.Whoareyou` instead of storing a second
copy of the packet in `Whoareyou.Encoded`. It's more correct this way
since `ChallengeData` is supposed to be the data that is used by the ID
verification procedure.
Also adapts the cross-client test to verify this behavior.
Follow-up to #31543
This adds the test description text to the output, instead of keeping it
as a Go comment. Logs are visible in the hive UI where these tests run,
while Go comments are not.
* p2p/discover: add more packet information in logs
This adds more fields to discv5 packet logs. These can be useful when
debugging multi-packet interactions.
The FINDNODE message also gets an additional field, OpID for debugging
purposes. This field is not encoded onto the wire.
I'm also removing topic system related message types in this change.
These will come back in the future, where support for them will be
guarded by a config flag.
* p2p/discover/v5wire: rename 'Total' to 'RespCount'
The new name captures the meaning of this field better.
