In this PR, we add support for protocol version eth/70, defined by EIP-7975.
Overall changes:
- Each response is buffered in the peer’s receipt buffer when the
`lastBlockIncomplete` field is true.
- Continued request uses the same request id of its original
request(`RequestPartialReceipts`).
- Partial responses are verified in `validateLastBlockReceipt`.
- Even if all receipts for partial blocks of the request are collected,
those partial results are not sinked to the downloader, to avoid
complexity. This assumes that partial response and buffering occur only
in exceptional cases.
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Co-authored-by: Gary Rong <garyrong0905@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This changes the p2p protocol handlers to delay message decoding. It's
the first part of a larger change that will delay decoding all the way
through message processing. For responses, we delay the decoding until
it is confirmed that the response matches an active request and does not
exceed its limits.
In order to make this work, all messages have been changed to use
rlp.RawList instead of a slice of the decoded item type. For block
bodies specifically, the decoding has been delayed all the way until
after verification of the response hash.
The role of p2p/tracker.Tracker changes significantly in this PR. The
Tracker's original purpose was to maintain metrics about requests and
responses in the peer-to-peer protocols. Each protocol maintained a
single global Tracker instance. As of this change, the Tracker is now
always active (regardless of metrics collection), and there is a
separate instance of it for each peer. Whenever a response arrives, it
is first verified that a request exists for it in the tracker. The
tracker is also the place where limits are kept.
