* core,eth/tracers: make isPrecompiled dependent on HF
* eth/tracers: use keys when constructing chain config struct
* eth/tracers: dont initialize activePrecompiles with random value
This change increases the cache size from 64 to 256 Mb for block bodies.
Benchmarks have shown this to be one bottleneck when trying to achieve
higher download speeds.
The commit also includes a minor optimization for header inserts in package
core: previously, the presence of headers in the database was checked for
every header before writing it. With the change, if one header fails the
presence check, all subsequent headers are also assumed to be missing.
This is an improvement because in practice, the headers are almost always
missing during sync.
* accounts/abi/bind: fix bounded contracts and sim backend for 1559
* accounts/abi/bind, ethclient: don't rely on chain config for gas prices
* all: enable London for all internal tests
* les: get receipt type info in les tests
* les: fix weird test
Co-authored-by: Martin Holst Swende <martin@swende.se>
* internal/ethapi: add baseFee to RPCMarshalHeader
* internal/ethapi: add FeeCap, Tip and correct GasPrice to EIP-1559 RPCTransaction results
* core,eth,les,internal: add support for tip estimation in gas price oracle
* internal/ethapi,eth/gasprice: don't suggest tip larger than fee cap
* core/types,internal: use correct eip1559 terminology for json marshalling
* eth, internal/ethapi: fix rebase problems
* internal/ethapi: fix rpc name of basefee
* internal/ethapi: address review concerns
* core, eth, internal, les: simplify gasprice oracle (#25)
* core, eth, internal, les: simplify gasprice oracle
* eth/gasprice: fix typo
* internal/ethapi: minor tweak in tx args
* internal/ethapi: calculate basefee for pending block
* internal/ethapi: fix panic
* internal/ethapi, eth/tracers: simplify txargs ToMessage
* internal/ethapi: remove unused param
* core, eth, internal: fix regressions wrt effective gas price in the evm
* eth/gasprice: drop weird debug println
* internal/jsre/deps: hack in 1559 gas conversions into embedded web3
* internal/jsre/deps: hack basFee to decimal conversion
* internal/ethapi: init feecap and tipcap for legacy txs too
* eth, graphql, internal, les: fix gas price suggestion on all combos
* internal/jsre/deps: handle decimal tipcap and feecap
* eth, internal: minor review fixes
* graphql, internal: export max fee cap RPC endpoint
* internal/ethapi: fix crash in transaction_args
* internal/ethapi: minor refactor to make the code safer
Co-authored-by: Ryan Schneider <ryanleeschneider@gmail.com>
Co-authored-by: lightclient@protonmail.com <lightclient@protonmail.com>
Co-authored-by: gary rong <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
There are two transaction parameter structures defined in
the codebase, although for different purposes. But most of
the parameters are shared. So it's nice to reduce the code
duplication by merging them together.
Co-authored-by: Martin Holst Swende <martin@swende.se>
This removes the error log message that says
Ethereum peer removal failed ... err="peer not registered"
The error happened because removePeer was called multiple
times: once to disconnect the peer, and another time when the
handler exited. With this change, removePeer now has the sole
purpose of disconnecting the peer. Unregistering happens exactly
once, when the handler exits.
* core/types, miner: create TxWithMinerFee wrapper, add EIP-1559 support to TransactionsByMinerFeeAndNonce
miner: set base fee when creating a new header, handle gas limit, log miner fees
* all: rename to NewTransactionsByPriceAndNonce
* core/types, miner: rename to NewTransactionsByPriceAndNonce + EffectiveTip
miner: activate 1559 for testGenerateBlockAndImport tests
* core,miner: revert naming to TransactionsByPriceAndTime
* core/types/transaction: update effective tip calculation logic
* miner: update aleut to london
* core/types/transaction_test: use correct signer for 1559 txs + add back sender check
* miner/worker: calculate gas target from gas limit
* core, miner: fix block gas limits for 1559
Co-authored-by: Ansgar Dietrichs <adietrichs@gmail.com>
Co-authored-by: lightclient@protonmail.com <lightclient@protonmail.com>
This change extracts the peer QoS tracking logic from eth/downloader, moving
it into the new package p2p/msgrate. The job of msgrate.Tracker is determining
suitable timeout values and request sizes per peer.
The snap sync scheduler now uses msgrate.Tracker instead of the hard-coded 15s
timeout. This should make the sync work better on network links with high latency.
This is the initial implementation of EIP-1559 in packages core/types and core.
Mining, RPC, etc. will be added in subsequent commits.
Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de>
Co-authored-by: lightclient@protonmail.com <lightclient@protonmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
This removes auto-configuration of the snap.*.ethdisco.net DNS discovery tree.
Since measurements have shown that > 75% of nodes in all.*.ethdisco.net support
snap, we have decided to retire the dedicated index for snap and just use the eth
tree instead.
The dial iterators of eth and snap now use the same DNS tree in the default configuration,
so both iterators should use the same DNS discovery client instance. This ensures that
the record cache and rate limit are shared. Records will not be requested multiple times.
While testing the change, I noticed that duplicate DNS requests do happen even
when the client instance is shared. This is because the two iterators request the tree
root, link tree root, and first levels of the tree in lockstep. To avoid this problem, the
change also adds a singleflight.Group instance in the client. When one iterator
attempts to resolve an entry which is already being resolved, the singleflight object
waits for the existing resolve call to finish and returns the entry to both places.
* eth/protocols/snap: generate storage trie from full dirty snap data
* eth/protocols/snap: get rid of some more dead code
* eth/protocols/snap: less frequent logs, also log during trie generation
* eth/protocols/snap: implement dirty account range stack-hashing
* eth/protocols/snap: don't loop on account trie generation
* eth/protocols/snap: fix account format in trie
* core, eth, ethdb: glue snap packets together, but not chunks
* eth/protocols/snap: print completion log for snap phase
* eth/protocols/snap: extended tests
* eth/protocols/snap: make testcase pass
* eth/protocols/snap: fix account stacktrie commit without defer
* ethdb: fix key counts on reset
* eth/protocols: fix typos
* eth/protocols/snap: make better use of delivered data (#44)
* eth/protocols/snap: make better use of delivered data
* squashme
* eth/protocols/snap: reduce chunking
* squashme
* eth/protocols/snap: reduce chunking further
* eth/protocols/snap: break out hash range calculations
* eth/protocols/snap: use sort.Search instead of looping
* eth/protocols/snap: prevent crash on storage response with no keys
* eth/protocols/snap: nitpicks all around
* eth/protocols/snap: clear heal need on 1-chunk storage completion
* eth/protocols/snap: fix range chunker, add tests
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
* trie: fix test API error
* eth/protocols/snap: fix some further liter issues
* eth/protocols/snap: fix accidental batch reuse
Co-authored-by: Martin Holst Swende <martin@swende.se>
* eth/protocols, prp/tracker: add support for req/rep rtt tracking
* p2p/tracker: sanity cap the number of pending requests
* pap/tracker: linter <3
* p2p/tracker: disable entire tracker if no metrics are enabled
This change adds the --catalyst flag, enabling an RPC API for eth2 integration.
In this initial version, catalyst mode also disables all peer-to-peer networking.
Co-authored-by: Mikhail Kalinin <noblesse.knight@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
* all: add thousandths separators for big numbers on log messages
* p2p/sentry: drop accidental file
* common, log: add fast number formatter
* common, eth/protocols/snap: simplifty fancy num types
* log: handle nil big ints
* core/vm: implement AccessListTracer
* eth: implement debug.createAccessList
* core/vm: fixed nil panics in accessListTracer
* eth: better error messages for createAccessList
* eth: some fixes on CreateAccessList
* eth: allow for provided accesslists
* eth: pass accesslist by value
* eth: remove created acocunt from accesslist
* core/vm: simplify access list tracer
* core/vm: unexport accessListTracer
* eth: return best guess if al iteration times out
* eth: return best guess if al iteration times out
* core: docstring, unexport methods
* eth: typo
* internal/ethapi: move createAccessList to eth package
* internal/ethapi: remove reexec from createAccessList
* internal/ethapi: break if al is equal to last run, not if gas is equal
* internal/web3ext: fixed arguments
* core/types: fixed equality check for accesslist
* core/types: no hardcoded vals
* core, internal: simplify access list generation, make it precise
* core/vm: fix typo
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
This removes the duplicated definition of eth_chainID
in package eth and updates the definition in internal/ethapi
to treat chain ID as a bigint.
Co-authored-by: Felix Lange <fjl@twurst.com>
The PR implements the --miner.notify.full flag that enables full pending block
notifications. When this flag is used, the block notifications sent to mining
endpoints contain the complete block header JSON instead of a work package
array.
Co-authored-by: AlexSSD7 <alexandersadovskyi7@protonmail.com>
Co-authored-by: Martin Holst Swende <martin@swende.se>
Fixes the CaptureStart api to include the EVM, thus being able to set the statedb early on. This pr also exposes the struct we used internally in the interpreter to encapsulate the contract, mem, stack, rstack, so we pass it as a single struct to the tracer, and removes the error returns on the capture methods.
This adds support for EIP-2718 typed transactions as well as EIP-2930
access list transactions (tx type 1). These EIPs are scheduled for the
Berlin fork.
There very few changes to existing APIs in core/types, and several new APIs
to deal with access list transactions. In particular, there are two new
constructor functions for transactions: types.NewTx and types.SignNewTx.
Since the canonical encoding of typed transactions is not RLP-compatible,
Transaction now has new methods for encoding and decoding: MarshalBinary
and UnmarshalBinary.
The existing EIP-155 signer does not support the new transaction types.
All code dealing with transaction signatures should be updated to use the
newer EIP-2930 signer. To make this easier for future updates, we have
added new constructor functions for types.Signer: types.LatestSigner and
types.LatestSignerForChainID.
This change also adds support for the YoloV3 testnet.
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>
Co-authored-by: Ryan Schneider <ryanleeschneider@gmail.com>
This PR adds a more CLI flag, so that the les-server can serve light clients even the local node is not synced yet.
This functionality is needed in some testing environments(e.g. hive). After launching the les server, no more blocks will be imported so the node is always marked as "non-synced".
This PR prevents users from submitting transactions without EIP-155 enabled. This behaviour can be overridden by specifying the flag --rpc.allow-unprotected-txs=true.
This PR optimizes the broadcast loop. Instead of iterating twice through a given set of transactions to weed out which peers have and which do not have a tx, to send/announce transactions, we do it only once.
Prevents a situation where we (not running snap) connects with a peer running snap, and get stalled waiting for snap registration to succeed (which will never happen), which cause a waitgroup wait to halt shutdown
This moves the eth config definition into a separate package, eth/ethconfig.
Packages eth and les can now import this common package instead of
importing eth from les, reducing dependencies.
Co-authored-by: Felix Lange <fjl@twurst.com>
The PR makes use of the stacktrie, which is is more lenient on resource consumption, than the regular trie, in cases where we only need it for DeriveSha
* remove uneeded convertion type
* remove redundant type in composite literal
* omit explicit type where implicit
* remove unused redundant parenthesis
* remove redundant import alias duktape
Removes the yolov2 definition, adds yolov3, including EIP-2565. This PR also disables some of the erroneously generated blockchain and statetests, and adds the new genesis hash + alloc for yolov3.
This PR disables the CLI switches for yolo, since it's not complete until we merge support for 2930.
This moves the tracing RPC API implementation to package eth/tracers.
By doing so, package eth no longer depends on tracing and the duktape JS engine.
The change also enables tracing using the light client. All tracing methods work with the
light client, but it's a lot slower compared to using a full node.
This PR introduces a new config field SyncFromCheckpoint for light client.
In some special scenarios, it's required to start synchronization from some
arbitrary checkpoint or even from the scratch. So this PR offers this
flexibility to users so that the synchronization start point can be configured.
There are two relevant configs: SyncFromCheckpoint and Checkpoint.
- If the SyncFromCheckpoint is true, the light client will try to sync from the
specified checkpoint.
- If the Checkpoint is not configured, then the light client will sync from the
scratch(from the latest header if the database is not empty)
Additional notes: these two configs are not visible in the CLI flags but only
accessable in the config file.
Example Usage:
[Eth]
SyncFromCheckpoint = true
[Eth.Checkpoint]
SectionIndex = 100
SectionHead = "0xabc"
CHTRoot = "0xabc"
BloomRoot = "0xabc"
PS. Historical checkpoint can be retrieved from the synced full node or light
client via les_getCheckpoint API.
This changes the chainID RPC method to return an error when EIP-155 is not yet
active at the current block height. It used to simply return zero in this case, but
that's confusing.
During the snap and eth refactor, the net_version rpc call was falsely deprecated.
This restores the net_version RPC handler as most eth2 nodes and other software
depend on it.
This commit splits the eth package, separating the handling of eth and snap protocols. It also includes the capability to run snap sync (https://github.com/ethereum/devp2p/blob/master/caps/snap.md) , but does not enable it by default.
Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de>
Co-authored-by: Martin Holst Swende <martin@swende.se>
This PR implements unclean shutdown marker. Every time geth boots, it adds a timestamp to a list of timestamps in the database. This list is capped at 10. At a clean shutdown, the timestamp is removed again.
Thus, when geth exits unclean, the marker remains, and at boot up we show the most recent unclean shutdowns to the user, which makes it easier to diagnose root-causes to certain problems.
Co-authored-by: Nagy Salem <me@muhnagy.com>
In miner/worker.go, there are two goroutine using channel w.newWorkCh: newWorkerLoop() sends to this channel, and mainLoop() receives from this channel. Only the receive operation is in a select.
However, w.exitCh may be closed by another goroutine. This is fine for the receive since receive is in select, but if the send operation is blocking, then it will block forever. This commit puts the send in a select, so it won't block even if w.exitCh is closed.
Similarly, there are two goroutines using channel errc: the parent that runs the test receives from it, and the child created at line 573 sends to it. If the parent goroutine exits too early by calling t.Fatalf() at line 614, then the child goroutine will be blocked at line 574 forever. This commit adds 1 buffer to errc. Now send will not block, and receive is not influenced because receive still needs to wait for the send.
* all: core: split vm.Config into BlockConfig and TxConfig
* core: core/vm: reset EVM between tx in block instead of creating new
* core/vm: added docs
core/types: use stacktrie for derivesha
trie: add stacktrie file
trie: fix linter
core/types: use stacktrie for derivesha
rebased: adapt stacktrie to the newer version of DeriveSha
Co-authored-by: Martin Holst Swende <martin@swende.se>
More linter fixes
review feedback: no key offset for nodes converted to hashes
trie: use EncodeRLP for full nodes
core/types: insert txs in order in derivesha
trie: tests for derivesha with stacktrie
trie: make stacktrie use pooled hashers
trie: make stacktrie reuse tmp slice space
trie: minor polishes on stacktrie
trie/stacktrie: less rlp dancing
core/types: explain the contorsions in DeriveSha
ci: fix goimport errors
trie: clear mem on subtrie hashing
squashme: linter fix
stracktrie: use pooling, less allocs (#3)
trie: in-place hex prefix, reduce allocs and add rawNode.EncodeRLP
Reintroduce the `[]node` method, add the missing `EncodeRLP` implementation for `rawNode` and calculate the hex prefix in place.
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Martin Holst Swende <martin@swende.se>
This changes how the downloader works, a little bit. Previously, when block sync started,
we immediately started filling up to 8192 blocks. Usually this is fine, blocks are small
in the early numbers. The threshold then is lowered as we measure the size of the blocks
that are filled.
However, if the node is shut down and restarts syncing while we're in a heavy segment,
that might be bad. This PR introduces a more conservative initial threshold of 2K blocks
instead.
* "Downloader queue stats" is now a DEBUG information
I think this info is more a DEBUG related information then an INFO. If it must remains an INFO, maybe it can be slow down to one time every 5 minutes or so.
* Update queue.go
"Downloader queue stats" information is now provided once every minute instead of once every 10 seconds.
This PR significantly changes the APIs for instantiating Ethereum nodes in
a Go program. The new APIs are not backwards-compatible, but we feel that
this is made up for by the much simpler way of registering services on
node.Node. You can find more information and rationale in the design
document: https://gist.github.com/renaynay/5bec2de19fde66f4d04c535fd24f0775.
There is also a new feature in Node's Go API: it is now possible to
register arbitrary handlers on the user-facing HTTP server. In geth, this
facility is used to enable GraphQL.
There is a single minor change relevant for geth users in this PR: The
GraphQL API is no longer available separately from the JSON-RPC HTTP
server. If you want GraphQL, you need to enable it using the
./geth --http --graphql flag combination.
The --graphql.port and --graphql.addr flags are no longer available.
* init
notes
removed some mentions of eth62, bumped protocol err too old to >=63
* remove sanity checks and bump supported protocol version up to 63
* remove 62 tests, still need to add 65
* remove 65 tests
* eth/downloader: refactor downloader + queue
downloader, fetcher: throttle-metrics, fetcher filter improvements, standalone resultcache
downloader: more accurate deliverytime calculation, less mem overhead in state requests
downloader/queue: increase underlying buffer of results, new throttle mechanism
eth/downloader: updates to tests
eth/downloader: fix up some review concerns
eth/downloader/queue: minor fixes
eth/downloader: minor fixes after review call
eth/downloader: testcases for queue.go
eth/downloader: minor change, don't set progress unless progress...
eth/downloader: fix flaw which prevented useless peers from being dropped
eth/downloader: try to fix tests
eth/downloader: verify non-deliveries against advertised remote head
eth/downloader: fix flaw with checking closed-status causing hang
eth/downloader: hashing avoidance
eth/downloader: review concerns + simplify resultcache and queue
eth/downloader: add back some locks, address review concerns
downloader/queue: fix remaining lock flaw
* eth/downloader: nitpick fixes
* eth/downloader: remove the *2*3/4 throttling threshold dance
* eth/downloader: print correct throttle threshold in stats
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
This change introduces garbage collection for the light client. Historical
chain data is deleted periodically. If you want to disable the GC, use
the --light.nopruning flag.
This fixes two issues with state sync restarts:
When sync restarts with a new root, some peers can have in-flight requests.
Since all peers with active requests were marked idle when exiting sync,
the new sync would schedule more requests for those peers. When the
response for the earlier request arrived, the new sync would reject it and
mark the peer idle again, rendering the peer useless until it disconnected.
The other issue was that peers would not be marked idle when they had
delivered a response, but the response hadn't been processed before
restarting the state sync. This also made the peer useless because it
would be permanently marked busy.
Co-authored-by: Felix Lange <fjl@twurst.com>
This PR reduces the bandwidth used by the light client to compute the
recommended gas price. The current mechanism for suggesting the price is:
- retrieve recent 20 blocks
- get the lowest gas price of these blocks
- sort the price array and return the middle(60%) one
This works for full nodes, which have all blocks available locally.
However, this is very expensive for the light client because the light
client needs to retrieve block bodies from the network.
The PR changes the default options for light client. With the new config,
the light client only retrieves the two latest blocks, but in order to
collect more sample transactions, the 3 lowest prices are collected from
each block.
This PR also changes the behavior for empty blocks. If the block is empty,
the lastest price is reused for sampling.
* eth/downloaded: fixed datarace between synchronize and Progress
There was a race condition between `downloader.synchronize()` and `Progress` `syncWithPeer` `fetchHeight` `findAncestors` and `processHeaders`
This PR changes the behavior of the downloader a bit.
Previously the functions `Progress` `syncWithPeer` `fetchHeight` `findAncestors` and `processHeaders` read the syncMode anew within their loops. Now they read the syncMode at the start of their function and don't change it during their runtime.
* eth/downloaded: comment
* eth/downloader: added comment
* core, crypto: various allocation savings regarding tx handling
* core: reduce allocs for gas price comparison
This change reduces the allocations needed for comparing different transactions to each other.
A call to `tx.GasPrice()` copies the gas price as it has to be safe against modifications and
also needs to be threadsafe. For comparing and ordering different transactions we don't need
these guarantees
* core: added tx.GasPriceIntCmp for comparison without allocation
adds a method to remove unneeded allocation in comparison to tx.gasPrice
* core/types: pool legacykeccak256 objects in rlpHash
rlpHash is by far the most used function in core that allocates a legacyKeccak256 object on each call.
Since it is so widely used it makes sense to add pooling here so we relieve the GC.
On my machine these changes result in > 100 MILLION less allocations and > 30 GB less allocated memory.
* reverted some changes
* reverted some changes
* trie: use crypto.KeccakState instead of replicating code
Co-authored-by: Martin Holst Swende <martin@swende.se>
* eth/downloader tests: fix spurious failing test due to race between receipts/headers
* miner tests: fix travis failure on arm64
* eth/downloader: tests - store td in ancients too
* core/vm: use fixed uint256 library instead of big
* core/vm: remove intpools
* core/vm: upgrade uint256, fixes uint256.NewFromBig
* core/vm: use uint256.Int by value in Stack
* core/vm: upgrade uint256 to v1.0.0
* core/vm: don't preallocate space for 1024 stack items (only 16)
Co-authored-by: Martin Holst Swende <martin@swende.se>
This PR makes use of go 1.13 error handling, wrapping errors and using
errors.Is to check a wrapped root-cause. It also removes the travis
builders for go 1.11 and go 1.12.
This adds a new API method on core.BlockChain to allow interrupting
running data inserts, and calls the method before shutting down the
downloader.
The BlockChain interrupt checks are now done through a method instead
of inlining the atomic load everywhere. There is no loss of efficiency from
this and it makes the interrupt protocol a lot clearer because the check is
defined next to the method that sets the flag.
This PR reimplements the light client server pool. It is also a first step
to move certain logic into a new lespay package. This package will contain
the implementation of the lespay token sale functions, the token buying and
selling logic and other components related to peer selection/prioritization
and service quality evaluation. Over the long term this package will be
reusable for incentivizing future protocols.
Since the LES peer logic is now based on enode.Iterator, it can now use
DNS-based fallback discovery to find servers.
This document describes the function of the new components:
https://gist.github.com/zsfelfoldi/3c7ace895234b7b345ab4f71dab102d4
* cmd, core, eth: init tx lookup in background
* core/rawdb: tiny log fixes to make it clearer what's happening
* core, eth: fix rebase errors
* core/rawdb: make reindexing less generic, but more optimal
* rlp: implement rlp list iterator
* core/rawdb: new implementation of tx indexing/unindex using generic tx iterator and hashing rlp-data
* core/rawdb, cmd/utils: fix review concerns
* cmd/utils: fix merge issue
* core/rawdb: add some log formatting polishes
Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
* all: seperate consensus error and evm internal error
There are actually two types of error will be returned when
a tranaction/message call is executed: (a) consensus error
(b) evm internal error. The former should be converted to
a consensus issue, e.g. The sender doesn't enough asset to
purchase the gas it specifies. The latter is allowed since
evm itself is a blackbox and internal error is allowed to happen.
This PR emphasizes the difference by introducing a executionResult
structure. The evm error is embedded inside. So if any error
returned, it indicates consensus issue happens.
And also this PR improve the `EstimateGas` API to return the concrete
revert reason if the transaction always fails
* all: polish
* accounts/abi/bind/backends: add tests
* accounts/abi/bind/backends, internal: cleanup error message
* all: address comments
* core: fix lint
* accounts, core, eth, internal: address comments
* accounts, internal: resolve revert reason if possible
* accounts, internal: address comments
This new API allows reading accounts and their content by address range.
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>
* eth: improve shutdown synchronization
Most goroutines started by eth.Ethereum didn't have any shutdown sync at
all, which lead to weird error messages when quitting the client.
This change improves the clean shutdown path by stopping all internal
components in dependency order and waiting for them to actually be
stopped before shutdown is considered done. In particular, we now stop
everything related to peers before stopping 'resident' parts such as
core.BlockChain.
* eth: rewrite sync controller
* eth: remove sync start debug message
* eth: notify chainSyncer about new peers after handshake
* eth: move downloader.Cancel call into chainSyncer
* eth: make post-sync block broadcast synchronous
* eth: add comments
* core: change blockchain stop message
* eth: change closeBloomHandler channel type
Prior to this change, eth_call changed the balance of the sender account in the
EVM environment to 2^256 wei to cover the gas cost of the call execution.
We've had this behavior for a long time even though it's super confusing.
This commit sets the default call gasprice to zero instead of updating the balance,
which is better because it makes eth_call semantics less surprising. Removing
the built-in balance assignment also makes balance overrides work as expected.