Fixed assigning values to variables we don't end up using.

No need to convert these types.

Make it select from all live nodes instead of selecting the heads of
random buckets.

* eth: chain config (genesis + fork) ENR entry

* core/forkid, eth: protocol independent fork ID, update to CRC32 spec

* core/forkid, eth: make forkid a struct, next uint64, enr struct, RLP

* core/forkid: change forkhash rlp encoding from int to [4]byte

* eth: fixup eth entry a bit and update it every block

* eth: fix lint

* eth: fix crash in ethclient tests

This entry was an experiment, but we're moving on to the
entry-per-protocol instead.

* all: implement simple checkpoint syncing

cmd, les, node: remove callback mechanism

cmd, node: remove callback definition

les: simplify the registrar

les: expose checkpoint rpc services in the light client

les, light: don't store untrusted receipt

cmd, contracts, les: discard stale checkpoint

cmd, contracts/registrar: loose restriction of registeration

cmd, contracts: add replay-protection

all: off-chain multi-signature contract

params: deploy checkpoint contract for rinkeby

cmd/registrar: add raw signing mode for registrar

cmd/registrar, contracts/registrar, les: fixed messages

* cmd/registrar, contracts/registrar: fix lints

* accounts/abi/bind, les: address comments

* cmd, contracts, les, light, params: minor checkpoint sync cleanups

* cmd, eth, les, light: move checkpoint config to config file

* cmd, eth, les, params: address comments

* eth, les, params: address comments

* cmd: polish up the checkpoint admin CLI

* cmd, contracts, params: deploy new version contract

* cmd/checkpoint-admin: add another flag for clef mode signing

* cmd, contracts, les: rename and regen checkpoint oracle with abigen

The dialer limits itself to one attempt every 30s. Apply the same limit
in Server and reject peers which try to connect too eagerly. The check
against the limit happens right after accepting the connection.

Further changes in this commit ensure we pass the Server logger
down to Peer instances, discovery and dialState. Unit test logging now
works in all Server tests.

* p2p/enr: add entries for for IPv4/IPv6 separation

This adds entry types for "ip6", "udp6", "tcp6" keys. The IP type stays
around because removing it would break a lot of code and force everyone
to care about the distinction.

* p2p/enode: track IPv4 and IPv6 address separately

LocalNode predicts the local node's UDP endpoint and updates the record.
This change makes it predict IPv4 and IPv6 endpoints separately since
they can now be in the record at the same time.

* p2p/enode: implement base64 text format
* all: switch to enode.Parse(...)

This allows passing base64-encoded node records to all the places that
previously accepted enode:// URLs. The URL format is still supported.

* cmd/bootnode, p2p: log node URL instead of ENR

...and return the base64 record in NodeInfo.

* p2p/discover: export Ping and RequestENR

These two are useful for checking the status of a node.

* cmd/devp2p: add devp2p debug tool

This is a new tool for debugging p2p issues. It supports a few
basic tasks for now, but many more things can and will be added
in the near future.

   devp2p enrdump            -- prints ENRs readably
   devp2p discv4 ping        -- checks if a node is up
   devp2p discv4 requestenr  -- gets a node's record
   devp2p discv4 resolve     -- finds a node through the DHT

* p2p: remove direct import of cgo-library

* accounts, rpc: more nocgo alternatives

* rpc: move unix path constant into separate file

* accounts/scwallet: address review concerns, remove copy-pasta

This change implements EIP-868. The UDPv4 transport announces support
for the extension in ping/pong and handles enrRequest messages.

There are two uses of the extension: If a remote node announces support
for EIP-868 in their pong, node revalidation pulls the node's record.
The Resolve method requests the record unconditionally.

swarm/storage/localstore: fix broken metric (#1373)

p2p/protocols: count different messages (#1374)

cmd/swarm: disable snapshot create test due to constant flakes (#1376)

swarm/network: remove redundant goroutine (#1377)

cmd/swarm/swarm-smoke: improve smoke tests (#1337)

swarm/network: remove dead code (#1339)

swarm/network: remove FetchStore and SyncChunkStore in favor of NetStore (#1342)

This change restructures the internals of p2p/discover to make room for
the discv5 code which will soon be added to this package.

- packet type names now have a "V4" suffix.
- ListenUDP returns *UDPv4 instead of *Table. This technically breaks
  the API but the only caller in go-ethereum is package p2p, which uses
  a compatible interface and doesn't need changes.
- The internal transport interface is changed to make Table reusable for v5.
- The 'lookup' code moves from table to transport. This required
  updating the lookup unit test to use udpTest instead of a custom transport.

* swarm/network: fix data races in TestInitialPeersMsg test

* swarm/network: add Kademlia.Saturation method with lock

* swarm/network: add Hive.Peer method to safely retrieve a bzz peer

* swarm/network: remove duplicate comment

* p2p/testing: prevent goroutine leak in ProtocolTester

* swarm/network: fix data race in newBzzBaseTesterWithAddrs

* swarm/network: fix goroutone leaks in testInitialPeersMsg

* swarm/network: raise number of peer check attempts in testInitialPeersMsg

* swarm/network: use Hive.Peer in Hive.PeerInfo function

* swarm/network: reduce the scope of mutex lock in newBzzBaseTesterWithAddrs

* swarm/storage: disable TestCleanIndex with race detector

This resolves a minor issue where neighbors responses containing less
than 16 nodes would bump the failure counter, removing the node. One
situation where this can happen is a private deployment where the total
number of extant nodes is less than 16.

Issue found by @jsying.

* cmd/swarm, p2p, swarm: Enable ENR in binary/execadapter

* cmd/p2p/swarm: Remove comments + config.Enode nomarshal

* p2p/simulations: Remove superfluous error check

* p2p/simulation: Move init enode comment

* swarm, p2p/simulations, cmd/swarm: Use nodekey in binary record sign

* swarm/network, swarm/pss: Dervice bzzkey

* swarm/pss: Remove unused function

* swarm/network: Store swarm private key in simulation bucket

* swarm/pss: Shorten TextProxNetwork shortrunning test timeout

* swarm/pss: Increase prox test timeout

* swarm/pss: Increase timeout slightly on shortrunning proxtest

* swarm/network: Simplify bucket instantiation in servicectx func

* p2p/simulations: Tcpport -> udpport

* swarm/network, swarm/pss: Simplify + correct lock in servicefunc sim

* swarm/network: Cleanup after rebase on extract swarm enode new

* p2p/simulations, swarm/network: Make exec disc test pass

* swarm/network: Prune ye olde comment

* swarm/pss: Correct revised bzzkey method call

* swarm/network: Clarify comment about privatekey generation data

* swarm/pss: Fix syntax errors after rebase

* swarm/network: Rename misleadingly named method

(amend commit to trigger ci - attempt 5)

* cmd/swarm, p2p, swarm: Enable ENR in binary/execadapter

* cmd/p2p/swarm: Remove comments + config.Enode nomarshal

* p2p/simulations: Remove superfluous error check

* p2p/simulation: Move init enode comment

* swarm/api: Check error in config test

* swarm, p2p/simulations, cmd/swarm: Use nodekey in binary record sign

* cmd/swarm: Make nodekey available for swarm api config

* swarm/api, swarm/network, p2p/simulations: Prerequisites for handshake remove

* swarm, p2p: Add full sim node configs for protocoltester

* swarm/network: Make stream package pass tests

* swarm/network: Extract peer and addr types out of protocol file

* p2p, swarm: Make p2p/protocols tests pass + rename types.go

* swarm/network: Deactivate ExecAdapter test until binary ENR prep

* swarm/api: Remove comments

* swarm/network: Uncomment bootnode record load

* dashboard, p2p: visualize peers

* dashboard: change scale to green to red

dummyHook's fields were concurrently written by nodes and read by
the test. The simplest solution is to protect all fields with a mutex.

Enable: TestMultiplePeersDropSelf, TestMultiplePeersDropOther as they
seemingly accidentally stayed disabled during a refactor/rewrite
since 1836366a.

resolves ethersphere/go-ethereum#1286

p2p/protocols: Fix race condition in TestAccountingSimulation

* p2p/simulations: increased snapshot load timeout for debugging

* swarm/network/stream: less nodes for snapshot longrunning tests

* swarm/network: fixed longrunning tests

* swarm/network/stream: store kademlia in bucket

* swarm/network/stream: disabled healthy check in delivery tests

* swarm/network/stream: longer SyncUpdateDelay for longrunning tests

* swarm/network/stream: more debug output

* swarm/network/stream: reduced longrunning snapshot tests to 64 nodes

* swarm/network/stream: don't WaitTillHealthy in SyncerSimulation

* swarm/network/stream: cleanup for PR

This change

- implements concurrent LES request serving even for a single peer.
- replaces the request cost estimation method with a cost table based on
  benchmarks which gives much more consistent results. Until now the
  allowed number of light peers was just a guess which probably contributed
  a lot to the fluctuating quality of available service. Everything related
  to request cost is implemented in a single object, the 'cost tracker'. It
  uses a fixed cost table with a global 'correction factor'. Benchmark code
  is included and can be run at any time to adapt costs to low-level
  implementation changes.
- reimplements flowcontrol.ClientManager in a cleaner and more efficient
  way, with added capabilities: There is now control over bandwidth, which
  allows using the flow control parameters for client prioritization.
  Target utilization over 100 percent is now supported to model concurrent
  request processing. Total serving bandwidth is reduced during block
  processing to prevent database contention.
- implements an RPC API for the LES servers allowing server operators to
  assign priority bandwidth to certain clients and change prioritized
  status even while the client is connected. The new API is meant for
  cases where server operators charge for LES using an off-protocol mechanism.
- adds a unit test for the new client manager.
- adds an end-to-end test using the network simulator that tests bandwidth
  control functions through the new API.

I added localItemKey for this purpose in #18963, but then
forgot to actually use it. This changes the database layout
yet again and requires bumping the version number.