enode.Node was recently changed to store a cache of endpoint information. The IP address in the cache is a netip.Addr. I chose that type over net.IP because it is just better. netip.Addr is meant to be used as a value type. Copying it does not allocate, it can be compared with ==, and can be used as a map key.
This PR changes most uses of Node.IP() into Node.IPAddr(), which returns the cached value directly without allocating.
While there are still some public APIs left where net.IP is used, I have converted all code used internally by p2p/discover to the new types. So this does change some public Go API, but hopefully not APIs any external code actually uses.
There weren't supposed to be any semantic differences resulting from this refactoring, however it does introduce one: In package p2p/netutil we treated the 0.0.0.0/8 network (addresses 0.x.y.z) as LAN, but netip.Addr.IsPrivate() doesn't. The treatment of this particular IP address range is controversial, with some software supporting it and others not. IANA lists it as special-purpose and invalid as a destination for a long time, so I don't know why I put it into the LAN list. It has now been marked as special in p2p/netutil as well.
Here we update the eth and snap protocol test suites with a new test chain,
created by the hivechain tool. The new test chain uses proof-of-stake. As such,
tests using PoW block propagation in the eth protocol are removed. The test suite
now connects to the node under test using the engine API in order to make it
accept transactions.
The snap protocol test suite has been rewritten to output test descriptions and
log requests more verbosely.
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Co-authored-by: Felix Lange <fjl@twurst.com>
