cdadd9874a
Historically, checkpoints have been manually specified and used both for
various optimizations and to protect against cheap DoS attacks by
rejecting forks deep in history. The primary motivation for manually
specifying the checkpoints was said optimizations, however, those
optimization portions have now been decoupled from checkpoints in favor
of other methods, so the only remaining use of checkpoints is the
aforementioned rejection of forks deep in history.
Thus, this reworks the old fork rejection logic to make it automatic
based on an ancestor that is two weeks worth of blocks behind the
hard-coded assumevalid block (clamped to the genesis block if necessary)
that is manually specified at each release as opposed to needing to
additionally manually specify checkpoints.
Note the distinction here between the hard-coded assumevalid block
specified at each release and the potentially overridden value specified
by a user via CLI configuration options. This is an important
distinction because old fork rejection affects consensus and thus must
not move around based on user configuration.
This approach means the user can still specify a more recent assume
valid hash or disable assume valid optimizations independently without
affecting the consensus logic while still removing the need to manually
specify additional checkpoints.
The following is a high level overview of the changes:
- Modifies the blockchain.Config struct as follows:
- Removes the LastestCheckpoint option
- Adds a AllowOldForks option
- Removes all code related to manually specified checkpoints and finding
candidates
- Removes the following errors since they are no longer used:
- ErrBadCheckpoint
- ErrCheckpointTimeTooOld
- Renames checkpointNode to rejectForksCheckpoint to make it clear that
is the only thing it applies to
- Adds logic to potentially reject forks deep in history as follows:
- Do not reject old forks if they are manually allowed or the
hard-coded assumevalid block is not specified for the network
- Automatically choose an ancestor that is two weeks worth of blocks
prior to the hard-coded assumevalid block (clamped to the genesis
block if necessary)
- Replaces --nocheckpoints CLI option with --allowoldforks
- Updates doc.go to match the changes to the CLI options
|
||
|---|---|---|
| .github | ||
| addrmgr | ||
| bech32 | ||
| blockchain | ||
| certgen | ||
| chaincfg | ||
| cmd | ||
| connmgr | ||
| container/apbf | ||
| contrib | ||
| crypto | ||
| database | ||
| dcrec | ||
| dcrjson | ||
| dcrutil | ||
| docs | ||
| gcs | ||
| hdkeychain | ||
| internal | ||
| lru | ||
| math/uint256 | ||
| peer | ||
| rpc/jsonrpc/types | ||
| rpcclient | ||
| rpctest | ||
| sampleconfig | ||
| txscript | ||
| wire | ||
| .dockerignore | ||
| .gitignore | ||
| blockdb.go | ||
| cert_test.go | ||
| CHANGES | ||
| config_test.go | ||
| config.go | ||
| dcrd.go | ||
| doc.go | ||
| go.mod | ||
| go.sum | ||
| ipc.go | ||
| LICENSE | ||
| log.go | ||
| networkparams_test.go | ||
| params.go | ||
| README.md | ||
| require.go | ||
| rpcadaptors.go | ||
| run_tests.sh | ||
| SECURITY.md | ||
| server.go | ||
| service_windows.go | ||
| signal_unix.go | ||
| signal.go | ||
| upnp.go | ||
dcrd
Decred Overview
Decred is a blockchain-based cryptocurrency with a strong focus on community
input, open governance, and sustainable funding for development. It utilizes a
hybrid proof-of-work and proof-of-stake mining system to ensure that a small
group cannot dominate the flow of transactions or make changes to Decred without
the input of the community. A unit of the currency is called a decred (DCR).
Latest Downloads
Core software:
- dcrd: a Decred full node daemon (this)
- dcrwallet: a CLI Decred wallet daemon
- dcrctl: a CLI client for dcrd and dcrwallet
Bundles:
- Decrediton: a GUI bundle for
dcrdanddcrwallet - CLI app suite:
a CLI bundle for
dcrdanddcrwallet
What is dcrd?
dcrd is a full node implementation of Decred written in Go (golang).
It acts as a fully-validating chain daemon for the Decred cryptocurrency. dcrd maintains the entire past transactional ledger of Decred and allows relaying of transactions to other Decred nodes around the world.
This software is currently under active development. It is extremely stable and has been in production use since February 2016.
It important to note that dcrd does NOT include wallet functionality. Users who desire a wallet will need to use dcrwallet(CLI) or Decrediton(GUI).
What is a full node?
The term 'full node' is short for 'fully-validating node' and refers to software that fully validates all transactions and blocks, as opposed to trusting a 3rd party. In addition to validating transactions and blocks, nearly all full nodes also participate in relaying transactions and blocks to other full nodes around the world, thus forming the peer-to-peer network that is the backbone of the Decred cryptocurrency.
The full node distinction is important, since full nodes are not the only type of software participating in the Decred peer network. For instance, there are 'lightweight nodes' which rely on full nodes to serve the transactions, blocks, and cryptographic proofs they require to function, as well as relay their transactions to the rest of the global network.
Why run dcrd?
As described in the previous section, the Decred cryptocurrency relies on having a peer-to-peer network of nodes that fully validate all transactions and blocks and then relay them to other full nodes.
Running a full node with dcrd contributes to the overall security of the network, increases the available paths for transactions and blocks to relay, and helps ensure there are an adequate number of nodes available to serve lightweight clients, such as Simplified Payment Verification (SPV) wallets.
Without enough full nodes, the network could be unable to expediently serve users of lightweight clients which could force them to have to rely on centralized services that significantly reduce privacy and are vulnerable to censorship.
In terms of individual benefits, since dcrd fully validates every block and transaction, it provides the highest security and privacy possible when used in conjunction with a wallet that also supports directly connecting to it in full validation mode, such as dcrwallet (CLI) and Decrediton (GUI). It is also ideal for businesses and services that need the most reliable and accurate data about transactions.
Minimum Recommended Specifications (dcrd only)
- 16 GB disk space (as of April 2022, increases over time, ~2 GB/yr)
- 2 GB memory (RAM)
- ~150 MB/day download, ~1.5 GB/day upload
- Plus one-time initial download of the entire block chain
- Windows 10 (server preferred), macOS, Linux
- High uptime
Getting Started
So, you've decided to help the network by running a full node. Great! Running dcrd is simple. All you need to do is install dcrd on a machine that is connected to the internet and meets the minimum recommended specifications, and launch it.
Also, make sure your firewall is configured to allow inbound connections to port 9108.
Installing and updating
Binaries (Windows/Linux/macOS)
Binary releases are provided for common operating systems and architectures. The easiest method is to download Decrediton from the link below, which will include dcrd. Advanced users may prefer the Command-line app suite, which includes dcrd and dcrwallet.
https://decred.org/downloads/
- How to verify binaries before installing: https://docs.decred.org/advanced/verifying-binaries/
- How to install the CLI Suite: https://docs.decred.org/wallets/cli/cli-installation/
- How to install Decrediton: https://docs.decred.org/wallets/decrediton/decrediton-setup/
Build from source (all platforms)
Install Dependencies
-
Go 1.17 or 1.18
Installation instructions can be found here: https://golang.org/doc/install. Ensure Go was installed properly and is a supported version:
$ go version $ go env GOROOT GOPATHNOTE:
GOROOTandGOPATHmust not be on the same path. Since Go 1.8 (2016),GOROOTandGOPATHare set automatically, and you do not need to change them. However, you still need to add$GOPATH/binto yourPATHin order to run binaries installed bygo getandgo install(On Windows, this happens automatically).Unix example -- add these lines to .profile:
PATH="$PATH:/usr/local/go/bin" # main Go binaries ($GOROOT/bin) PATH="$PATH:$HOME/go/bin" # installed Go projects ($GOPATH/bin) -
Git
Installation instructions can be found at https://git-scm.com or https://gitforwindows.org.
$ git version
Windows Example
PS> git clone https://github.com/decred/dcrd $env:USERPROFILE\src\dcrd
PS> cd $env:USERPROFILE\src\dcrd
PS> go install . .\cmd\...
PS> dcrd -V
Run the dcrd executable now installed in "$(go env GOPATH)\bin".
Unix Example
This assumes you have already added $GOPATH/bin to your $PATH as described
in dependencies.
$ git clone https://github.com/decred/dcrd $HOME/src/dcrd
$ git clone https://github.com/decred/dcrctl $HOME/src/dcrctl
$ (cd $HOME/src/dcrd && go install . ./...)
$ (cd $HOME/src/dcrctl && go install)
$ dcrd -V
Run the dcrd executable now installed in $GOPATH/bin.
Building and Running OCI Containers (aka Docker/Podman)
The project does not officially provide container images. However, all of the
necessary files to build your own lightweight non-root container image based on
scratch from the latest source code are available in
contrib/docker.
It is also worth noting that, to date, most users typically prefer to run dcrd
directly, without using a container, for at least a few reasons:
dcrdis a static binary that does not require root privileges and therefore does not suffer from the usual deployment issues that typically make containers attractive- It is harder and more verbose to run
dcrdfrom a container as compared to normal:dcrdis designed to automatically create a working default configuration which means it just works out of the box without the need for additional configuration for almost all typical users- The blockchain data and configuration files need to be persistent which means configuring and managing a docker data volume
- Running non-root containers with
dockerrequires special care in regards to permissions
Running Tests
All tests and linters may be run using the script run_tests.sh. Generally,
Decred only supports the current and previous major versions of Go.
./run_tests.sh
Contact
If you have any further questions you can find us at:
Issue Tracker
The integrated github issue tracker is used for this project.
Documentation
The documentation for dcrd is a work-in-progress. It is located in the docs folder.
License
dcrd is licensed under the copyfree ISC License.