Instead of having the block manager notify the RPC server about
accepted, connected, and disconnected blocks, the RPC server will
directly listen for notifications from the blockchain.
The objective is to remove the reference from blockManager to
server. Since the blockManager is responsible for keeping the mempool
in sync, it should have a direct reference to it.
The BlockChain struct emits notifications for various events, but
it is only possible to register one listener. This changes the
interface and implementations to allow multiple listeners.
This commit modifies the existing block selection logic to limit
preferentially by weight instead of serialized block size, and also to
adhere to the new sig-op cost limits which are weighted according to
the witness discount.
This commit modifies the logic within the block manager and service to
preferentially fetch transactions and blocks which include witness data
from fully upgraded peers.
Once the initial version handshake has completed, the server now tracks
which of the connected peers are witness enabled (they advertise
SFNodeWitness). From then on, if a peer is witness enabled, then btcd
will always request full witness data when fetching
transactions/blocks.
This modifies the blockNode and BestState structs in the blockchain
package to store hashes directly instead of pointers to them and updates
callers to deal with the API change in the exported BestState struct.
In general, the preferred approach for hashes moving forward is to store
hash values in complex data structures, particularly those that will be
used for cache entries, and accept pointers to hashes in arguments to
functions.
Some of the reasoning behind making this change is:
- It is generally preferred to avoid storing pointers to data in cache
objects since doing so can easily lead to storing interior pointers
into other structs that then can't be GC'd
- Keeping the hash values directly in the block node provides better
cache locality
This contains a bit of cleanup and additional logic to improve the
recently-added ability to specify additional checkpoints via the
--addcheckpoint option.
In particular:
- Improve error messages in the checkpoint parsing
- Correct the mergeCheckpoints function to weed out duplicate height
checkpoints while using the most-recently provided one as described by
its comment
- Add an assertion to blockchain.New that the provided checkpoints are
sorted as required
- Keep comments to 80 columns and use two spaces after periods in them to
be consistent with the rest of the code base
- Make the entry in doc.go match the actual btcd -h output
This allows a caller-provided tag to be associated with orphan
transactions. This is useful since the caller can use the tag for
purposes such as keeping track of which peers orphans were first seen
from.
Also, since a parameter is required now anyways, it associates the peer
ID with processed transactions from remote peers.
This modifies the way orphan removal and processing is done to more
aggressively remove orphans that can no longer be valid due to other
transactions being added or removed from the primary transaction pool.
The net effect of these changes is that orphan pool will typically be
much smaller which greatly improves its effectiveness. Previously, it
would typically quickly reach the max allowed worst-case usage and
effectively stay there forever.
The following is a summary of the changes:
- Modify the map that tracks which orphans redeem a given transaction to
instead track by the specific outpoints that are redeemed
- Modify the various orphan removal and processing functions to accept
the full transaction rather than just its hash
- Introduce a new flag on removeOrphans which specifies whether or not
to remove the transactions that redeem the orphan being removed as
well which is necessary since only some paths require it
- Add a new function named removeOrphanDoubleSpends that is invoked
whenever a transaction is added to the main pool and thus the outputs
they spent become concrete spends
- Introduce a new flag on maybeAcceptTransaction which specifies whether
or not duplicate orphans should be rejected since only some paths
require it
- Modify processOrphans as follows:
- Make use of the modified map
- Use newly available flags and logic work more strictly work with tx
chains
- Recursively remove any orphans that also redeem any outputs redeemed
by the accepted transactions
- Several new tests to ensure proper functionality
- Removing an orphan that doesn't exist is removed both when there is
another orphan that redeems it and when there is not
- Removing orphans works properly with orphan chains per the new
remove redeemers flag
- Removal of multi-input orphans that double spend an output when a
concrete redeemer enters the transaction pool
This removes the exported CalcPastTimeMedian function from the
blockchain package as it is no longer needed since the information is
now available via the BestState snapshot.
Also, update the only known caller of this, which is the chain state in
block manager, to use the snapshot instead. In reality, now that
everything the block manager chain state provides is available via the
blockchain BestState snapshot, the entire thing can be removed, however
that will be done in a separate to commit to keep the changes targeted.
This modifies the blockchain.ProcessBlock function to return an
additional boolean as the first parameter which indicates whether or not
the block ended up on the main chain.
This is primarily useful for upcoming test code that needs to be able to
tell the difference between a block accepted to a side chain and a block
that either extends the main chain or causes a reorganize that causes it
to become the main chain. However, it is also useful for the addblock
utility since it allows a better error in the case a file with out of
order blocks is provided.
This does the minimum work necessary to refactor the mempool code into
its own package. The idea is that separating this code into its own
package will greatly improve its testability, allow independent
benchmarking and profiling, and open up some interesting opportunities
for future development related to the memory pool.
There are likely some areas related to policy that could be further
refactored, however it is better to do that in future commits in order
to keep the changeset as small as possible during this refactor.
Overview of the major changes:
- Create the new package
- Move several files into the new package:
- mempool.go -> mempool/mempool.go
- mempoolerror.go -> mempool/error.go
- policy.go -> mempool/policy.go
- policy_test.go -> mempool/policy_test.go
- Update mempool logging to use the new mempool package logger
- Rename mempoolPolicy to Policy (so it's now mempool.Policy)
- Rename mempoolConfig to Config (so it's now mempool.Config)
- Rename mempoolTxDesc to TxDesc (so it's now mempool.TxDesc)
- Rename txMemPool to TxPool (so it's now mempool.TxPool)
- Move defaultBlockPrioritySize to the new package and export it
- Export DefaultMinRelayTxFee from the mempool package
- Export the CalcPriority function from the mempool package
- Introduce a new RawMempoolVerbose function on the TxPool and update
the RPC server to use it
- Update all references to the mempool to use the package.
- Add a skeleton README.md
This is mostly a backport of some of the same modifications made in
Decred along with a few additional things cleaned up. In particular,
this updates the code to make use of the new chainhash package.
Also, since this required API changes anyways and the hash algorithm is
no longer tied specifically to SHA, all other functions throughout the
code base which had "Sha" in their name have been changed to Hash so
they are not incorrectly implying the hash algorithm.
The following is an overview of the changes:
- Remove the wire.ShaHash type
- Update all references to wire.ShaHash to the new chainhash.Hash type
- Rename the following functions and update all references:
- wire.BlockHeader.BlockSha -> BlockHash
- wire.MsgBlock.BlockSha -> BlockHash
- wire.MsgBlock.TxShas -> TxHashes
- wire.MsgTx.TxSha -> TxHash
- blockchain.ShaHashToBig -> HashToBig
- peer.ShaFunc -> peer.HashFunc
- Rename all variables that included sha in their name to include hash
instead
- Update for function name changes in other dependent packages such as
btcutil
- Update copyright dates on all modified files
- Update glide.lock file to use the required version of btcutil
Rather than making the caller to pass in the median time source on
ProcessBlock and IsCurrent, modify the Config struct to include the
median time source and associate it with the chain instance when it is
created.
This is being done because both the ProcessBlock and IsCurrent functions
require access to the blockchain state already, it is a little bit safer
to ensure the time source matches the chain instance state, it
simplifies the caller logic, and it also allows its use within the logic
of the blockchain package itself which will be required by upcoming
rule change warning logic that is part of BIP9.
This adds support for serving headers instead of inventory messages in
accordance with BIP0130. btcd itself does not yet make use of the
feature when receiving data.
It is not the responsibility of mempool to relay transactions, so
return a slice of transactions accepted to the mempool due to the
passed transaction to the caller.
This introduces a new indexing infrastructure for supporting optional
indexes using the new database and blockchain infrastructure along with
two concrete indexer implementations which provide both a
transaction-by-hash and a transaction-by-address index.
The new infrastructure is mostly separated into a package named indexers
which is housed under the blockchain package. In order to support this,
a new interface named IndexManager has been introduced in the blockchain
package which provides methods to be notified when the chain has been
initialized and when blocks are connected and disconnected from the main
chain. A concrete implementation of an index manager is provided by the
new indexers package.
The new indexers package also provides a new interface named Indexer
which allows the index manager to manage concrete index implementations
which conform to the interface.
The following is high level overview of the main index infrastructure
changes:
- Define a new IndexManager interface in the blockchain package and
modify the package to make use of the interface when specified
- Create a new indexers package
- Provides an Index interface which allows concrete indexes to plugin
to an index manager
- Provides a concrete IndexManager implementation
- Handles the lifecycle of all indexes it manages
- Tracks the index tips
- Handles catching up disabled indexes that have been reenabled
- Handles reorgs while the index was disabled
- Invokes the appropriate methods for all managed indexes to allow
them to index and deindex the blocks and transactions
- Implement a transaction-by-hash index
- Makes use of internal block IDs to save a significant amount of
space and indexing costs over the old transaction index format
- Implement a transaction-by-address index
- Makes use of a leveling scheme in order to provide a good tradeoff
between space required and indexing costs
- Supports enabling and disabling indexes at will
- Support the ability to drop indexes if they are no longer desired
The following is an overview of the btcd changes:
- Add a new index logging subsystem
- Add new options --txindex and --addrindex in order to enable the
optional indexes
- NOTE: The transaction index will automatically be enabled when the
address index is enabled because it depends on it
- Add new options --droptxindex and --dropaddrindex to allow the indexes
to be removed
- NOTE: The address index will also be removed when the transaction
index is dropped because it depends on it
- Update getrawtransactions RPC to make use of the transaction index
- Reimplement the searchrawtransaction RPC that makes use of the address
index
- Update sample-btcd.conf to include sample usage for the new optional
index flags
This commit is the first stage of several that are planned to convert
the blockchain package into a concurrent safe package that will
ultimately allow support for multi-peer download and concurrent chain
processing. The goal is to update btcd proper after each step so it can
take advantage of the enhancements as they are developed.
In addition to the aforementioned benefit, this staged approach has been
chosen since it is absolutely critical to maintain consensus.
Separating the changes into several stages makes it easier for reviewers
to logically follow what is happening and therefore helps prevent
consensus bugs. Naturally there are significant automated tests to help
prevent consensus issues as well.
The main focus of this stage is to convert the blockchain package to use
the new database interface and implement the chain-related functionality
which it no longer handles. It also aims to improve efficiency in
various areas by making use of the new database and chain capabilities.
The following is an overview of the chain changes:
- Update to use the new database interface
- Add chain-related functionality that the old database used to handle
- Main chain structure and state
- Transaction spend tracking
- Implement a new pruned unspent transaction output (utxo) set
- Provides efficient direct access to the unspent transaction outputs
- Uses a domain specific compression algorithm that understands the
standard transaction scripts in order to significantly compress them
- Removes reliance on the transaction index and paves the way toward
eventually enabling block pruning
- Modify the New function to accept a Config struct instead of
inidividual parameters
- Replace the old TxStore type with a new UtxoViewpoint type that makes
use of the new pruned utxo set
- Convert code to treat the new UtxoViewpoint as a rolling view that is
used between connects and disconnects to improve efficiency
- Make best chain state always set when the chain instance is created
- Remove now unnecessary logic for dealing with unset best state
- Make all exported functions concurrent safe
- Currently using a single chain state lock as it provides a straight
forward and easy to review path forward however this can be improved
with more fine grained locking
- Optimize various cases where full blocks were being loaded when only
the header is needed to help reduce the I/O load
- Add the ability for callers to get a snapshot of the current best
chain stats in a concurrent safe fashion
- Does not block callers while new blocks are being processed
- Make error messages that reference transaction outputs consistently
use <transaction hash>:<output index>
- Introduce a new AssertError type an convert internal consistency
checks to use it
- Update tests and examples to reflect the changes
- Add a full suite of tests to ensure correct functionality of the new
code
The following is an overview of the btcd changes:
- Update to use the new database and chain interfaces
- Temporarily remove all code related to the transaction index
- Temporarily remove all code related to the address index
- Convert all code that uses transaction stores to use the new utxo
view
- Rework several calls that required the block manager for safe
concurrency to use the chain package directly now that it is
concurrent safe
- Change all calls to obtain the best hash to use the new best state
snapshot capability from the chain package
- Remove workaround for limits on fetching height ranges since the new
database interface no longer imposes them
- Correct the gettxout RPC handler to return the best chain hash as
opposed the hash the txout was found in
- Optimize various RPC handlers:
- Change several of the RPC handlers to use the new chain snapshot
capability to avoid needlessly loading data
- Update several handlers to use new functionality to avoid accessing
the block manager so they are able to return the data without
blocking when the server is busy processing blocks
- Update non-verbose getblock to avoid deserialization and
serialization overhead
- Update getblockheader to request the block height directly from
chain and only load the header
- Update getdifficulty to use the new cached data from chain
- Update getmininginfo to use the new cached data from chain
- Update non-verbose getrawtransaction to avoid deserialization and
serialization overhead
- Update gettxout to use the new utxo store versus loading
full transactions using the transaction index
The following is an overview of the utility changes:
- Update addblock to use the new database and chain interfaces
- Update findcheckpoint to use the new database and chain interfaces
- Remove the dropafter utility which is no longer supported
NOTE: The transaction index and address index will be reimplemented in
another commit.
This optimizes the way in which the maps are limited by the block
manager.
Previously the code would read a cryptographically random value large
enough to construct a hash, find the first entry larger than that value,
and evict it.
That approach is quite inefficient and could easily become a bottleneck
when processing transactions due to the need to read from a source such
as /dev/urandom and all of the subsequent hash comparisons.
Luckily, strong cryptographic randomness is not needed here. The primary
intent of limiting the maps is to control memory usage with a secondary
concern of making it difficult for adversaries to force eviction of
specific entries.
Consequently, this changes the code to make use of the pseudorandom
iteration order of Go's maps along with the preimage resistance of the
hashing function to provide the desired functionality. It has
previously been discussed that the specific pseudorandom iteration order
is not guaranteed by the Go spec even though in practice that is how it
is implemented. This is not a concern however because even if the
specific compiler doesn't implement that, the preimage resistance of the
hashing function alone is enough.
Thanks to @Roasbeef for pointing out the efficiency concerns and the
fact that strong cryptographic randomness is not necessary.
This prevents the node from repeatedly requesting and rejecting the
same transaction as different peers inv the same transaction.
Idea from Bitcoin Core commit 0847d9cb5fcd2fdd5a21bde699944d966cf5add9
Also, limit the number of both requested blocks and transactions.
This commit introduces package peer which contains peer related features
refactored from peer.go.
The following is an overview of the features the package provides:
- Provides a basic concurrent safe bitcoin peer for handling bitcoin
communications via the peer-to-peer protocol
- Full duplex reading and writing of bitcoin protocol messages
- Automatic handling of the initial handshake process including protocol
version negotiation
- Automatic periodic keep-alive pinging and pong responses
- Asynchronous message queueing of outbound messages with optional
channel for notification when the message is actually sent
- Inventory message batching and send trickling with known inventory
detection and avoidance
- Ability to wait for shutdown/disconnect
- Flexible peer configuration
- Caller is responsible for creating outgoing connections and listening
for incoming connections so they have flexibility to establish
connections as they see fit (proxies, etc.)
- User agent name and version
- Bitcoin network
- Service support signalling (full nodes, bloom filters, etc.)
- Maximum supported protocol version
- Ability to register callbacks for handling bitcoin protocol messages
- Proper handling of bloom filter related commands when the caller does
not specify the related flag to signal support
- Disconnects the peer when the protocol version is high enough
- Does not invoke the related callbacks for older protocol versions
- Snapshottable peer statistics such as the total number of bytes read
and written, the remote address, user agent, and negotiated protocol
version
- Helper functions for pushing addresses, getblocks, getheaders, and
reject messages
- These could all be sent manually via the standard message output
function, but the helpers provide additional nice functionality such
as duplicate filtering and address randomization
- Full documentation with example usage
- Test coverage
In addition to the addition of the new package, btcd has been refactored
to make use of the new package by extending the basic peer it provides to
work with the blockmanager and server to act as a full node. The
following is a broad overview of the changes to integrate the package:
- The server is responsible for all connection management including
persistent peers and banning
- Callbacks for all messages that are required to implement a full node
are registered
- Logic necessary to serve data and behave as a full node is now in the
callback registered with the peer
Finally, the following peer-related things have been improved as a part
of this refactor:
- Don't log or send reject message due to peer disconnects
- Remove trace logs that aren't particularly helpful
- Finish an old TODO to switch the queue WaitGroup over to a channel
- Improve various comments and fix some code consistency cases
- Improve a few logging bits
- Implement a most-recently-used nonce tracking for detecting self
connections and generate a unique nonce for each peer
Introduce an ECDSA signature verification into btcd in order to
mitigate a certain DoS attack and as a performance optimization.
The benefits of SigCache are two fold. Firstly, usage of SigCache
mitigates a DoS attack wherein an attacker causes a victim's client to
hang due to worst-case behavior triggered while processing attacker
crafted invalid transactions. A detailed description of the mitigated
DoS attack can be found here: https://bitslog.wordpress.com/2013/01/23/fixed-bitcoin-vulnerability-explanation-why-the-signature-cache-is-a-dos-protection/
Secondly, usage of the SigCache introduces a signature verification
optimization which speeds up the validation of transactions within a
block, if they've already been seen and verified within the mempool.
The server itself manages the sigCache instance. The blockManager and
txMempool respectively now receive pointers to the created sigCache
instance. All read (sig triplet existence) operations on the sigCache
will not block unless a separate goroutine is adding an entry (writing)
to the sigCache. GetBlockTemplate generation now also utilizes the
sigCache in order to avoid unnecessarily double checking signatures
when generating a template after previously accepting a txn to the
mempool. Consequently, the CPU miner now also employs the same
optimization.
The maximum number of entries for the sigCache has been introduced as a
config parameter in order to allow users to configure the amount of
memory consumed by this new additional caching.
This commit converts all block height references to int32 instead of
int64. The current target block production rate is 10 mins per block
which means it will take roughly 40,800 years to reach the maximum
height an int32 affords. Even if the target rate were lowered to one
block per minute, it would still take roughly another 4,080 years to
reach the maximum.
In the mean time, there is no reason to use a larger type which results
in higher memory and disk space usage. However, for now, in order to
avoid having to reserialize a bunch of database information, the heights
are still serialized to the database as 8-byte uint64s.
This is being mainly being done in preparation for further upcoming
infrastructure changes which will use the smaller and more efficient
4-byte serialization in the database as well.
This commit corrects an issue where the reject message sent in response
to rejected transactions had the Cmd field set to "block" instead of
"tx".
Fixes#436.
The option -maxorphantx allows the user to specify the number of
orphan transactions to keep in memory.
Also, lower the default max orphan count from 10000 to 1000.
This commit removes the error returns from the BlockHeader.BlockSha,
MsgBlock.BlockSha, and MsgTx.TxSha functions since they can never fail and
end up causing a lot of unneeded error checking throughout the code base.
It also updates all call sites for the change.
Because FetchTransactionStore in GetBlockTemplate occasionally accesses
the internal blockchain memory structure while it is being read or modified,
a race can occur. To prevent this, FetchTransactionStore is instead
routed through the internal channel for blockchain requests.
In order to avoid prior situations of stalled syncs due to
outdated peer height data, we now update block heights up peers in
real-time as we learn of their announced
blocks.
Updates happen when:
* A peer sends us an orphan block. We update based on
the height embedded in the scriptSig for the coinbase tx
* When a peer sends us an inv for a block we already know
of
* When peers announce new blocks. Subsequent
announcements that lost the announcement race are
recognized and peer heights are updated accordingly
Additionally, the `getpeerinfo` command has been modified
to include both the starting height, and current height of
connected peers.
Docs have been updated with `getpeerinfo` extension.
For every transaction in a newly accepted block, process the orphan
pool moving now no longer orphan transactions to the mempool.
Previously, no longer orphan transactions would remain in the orphan
pool.
This modifies the recently added code which rejects free/low-fee
transactions with insufficient priority to ignore resurrected transactions
from disconnected blocks. It also exempts resurrected transactions from
the free/low-fee rate limiting.
This changes the behavior of the rescan RPC to automatically set the
client up for transaction notifications for transactions paying to any
rescanned address and spending outputs in the final rescan UTXO set
after a rescanned is performed through the best block in the chain.
