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.
The --blocksonly configuration option disables accepting transactions
from remote peers. It will still accept, relay, and rebroadcast
valid transactions sent via RPC or websockets.
Dynamic ban scores consist of a persistent and a decaying component. The
persistent score can be used to create simple additive banning policies
simlar to those found in other bitcoin node implementations. The
decaying score enables the creation of evasive logic which handles
misbehaving peers (especially application layer DoS attacks) gracefully
by disconnecting and banning peers attempting various kinds of flooding.
Dynamic ban scores allow these two approaches to be used in tandem.
This pull request includes the following:
- Dynamic ban score type & functions, with tests for core functionality
- Ban score of connected peers can be queried via rpc (getpeerinfo)
- Example policy with decaying score increments on mempool and getdata
- Logging of misbehavior once half of the ban threshold is reached
- Banning logic can be disabled via configuration (enabled by default)
- User defined ban threshold can be set via configuration
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.
SFNodeBloom is a new service flag that a node is required to use to
indicate that it supports bloom filtering. This includes a protocol
version bump to 70011 and a wire version bump to 0.3.0.
btcd:
The SFNodeBloom flag is set by default. A new configuration option
--nopeerbloomfilters has been added to to disable bloom filtering.
Any node advertising a version greater than or equal to 70011 that
attempts to use bloom filtering will be disconnected if bloom
filtering is disabled.
This mimics Bitcoin Core commit afb0ccaf9c9e4e8fac7db3564c4e19c9218c6b03
Tor stream isolation randomizes proxy user credentials resulting in
Tor creating a new circuit for each connection. This makes it more
difficult to correlate connections.
Idea from Wladimir J. van der Laan via Bitcoin Core.
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.
The limited user is specified with the --rpclimituser and
--rpclimitpass options (or the equivalent in the config file).
The config struct and loadConfig() are updated to take the
new options into account. The limited user can have neither
the same username nor the same password as the admin user.
The package-level rpcLimit map in rpcserver.go specifies
the RPC commands accessible by limited users. This map
includes both HTTP/S and websocket commands.
The checkAuth function gets a new return parameter to
signify whether the user is authorized to change server
state. The result is passed to the jsonRPCRead function and
to the WebsocketHandler function in rpcwebsocket.go.
The wsClient struct is updated with an "isAdmin" field
signifying that the client is authorized to change server
state, written by WebsocketHandler and handleMessage.
The handleMessage function also checks the field to
allow or disallow an RPC call.
The following documentation files are updated:
- doc.go
- sample-btcd.conf
- docs/README.md
- docs/json_rpc_api.md
- docs/configure_rpc_server_listen_interfaces.md
* Address index is built up concurrently with the `--addrindex` flag.
* Entire index can be deleted with `--dropaddrindex`.
* New RPC call: `searchrawtransaction`
* Returns all transacitons related to a particular address
* Includes mempool transactions
* Requires `--addrindex` to be activated and fully caught up.
* New `blockLogger` struct has been added to factor our common logging
code
* Wiki and docs updated with new features.
This commit introduces a new flag, --notls, which can be used to disable
TLS for the RPC server. However, the flag can only be used when the RPC
server is bound to localhost interfaces. This is intended to prevent the
situation where someone decides they want to expose the RPC server to the
web for remote management/access, but forgot they have TLS disabled.
This commit implements a built-in concurrent CPU miner that can be enabled
with the combination of the --generate and --miningaddr options. The
--blockminsize, --blockmaxsize, and --blockprioritysize configuration
options wich already existed prior to this commit control the block
template generation and hence affect blocks mined via the new CPU miner.
The following is a quick overview of the changes and design:
- Starting btcd with --generate and no addresses specified via
--miningaddr will give an error and exit immediately
- Makes use of multiple worker goroutines which independently create block
templates, solve them, and submit the solved blocks
- The default number of worker threads are based on the number of
processor cores in the system and can be dynamically changed at
run-time
- There is a separate speed monitor goroutine used to collate periodic
updates from the workers to calculate overall hashing speed
- The current mining state, number of workers, and hashes per second can
be queried
- Updated sample-btcd.conf file has been updated to include the coin
generation (mining) settings
- Updated doc.go for the new command line options
In addition the old --getworkkey option is now deprecated in favor of the
new --miningaddr option. This was changed for a few reasons:
- There is no reason to have a separate list of keys for getwork and CPU
mining
- getwork is deprecated and will be going away in the future so that means
the --getworkkey flag will also be going away
- Having the work 'key' in the option can be confused with wanting a
private key while --miningaddr make it a little more clear it is an
address that is required
Closes#137.
Reviewed by @jrick.
This commit adds a new configuration option, --rpcmaxclients, to limit the
number of max standard RPC clients that are served concurrently. Note
that this value does not apply to websocket connections. A future commit
will add support for limiting those separately.
Closes#68.
This implements --onion (and --onionuser/--onionpass) that enable a
different proxy to be used to connect to .onion addresses. If no main
proxy is supplied then no proxy will be used for non-onion addresses.
Additionally we add --noonion that blocks connection attempts to .onion
addresses entirely (and avoids using tor for proxy dns lookups).
the --tor option has been supersceded and thus removed.
Closes#47
