mirror of
https://github.com/guggero/chantools
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350 lines
19 KiB
Markdown
350 lines
19 KiB
Markdown
# Channel tools
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## Index
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* [Installation](#installation)
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* [Channel recovery scenario](#channel-recovery-scenario)
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* [Seed and passphrase input](#seed-and-passphrase-input)
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* [Command overview](#command-overview)
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* [Commands](#commands)
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This tool provides helper functions that can be used to rescue funds locked in
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`lnd` channels in case `lnd` itself cannot run properly anymore.
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**WARNING**: This tool was specifically built for a certain rescue operation and
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might not be well-suited for your use case. Or not all edge cases for your needs
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are coded properly. Please look at the code to understand what it does before
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you use it for anything serious.
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**WARNING 2**: This tool will query public block explorer APIs for some
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commands, your privacy might not be preserved. Use at your own risk or supply
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a private API URL with `--apiurl`.
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## Installation
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The easiest way to install `chantools` is to [download a pre-built binary for
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your operating system and architecture](https://github.com/guggero/chantools/releases).
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Example (make sure you always use the latest version!):
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```shell
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$ cd /tmp
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$ wget -O chantools.tar.gz https://github.com/guggero/chantools/releases/download/v0.10.4/chantools-linux-amd64-v0.10.4.tar.gz
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$ tar -zxvf chantools.tar.gz
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$ sudo mv chantools-*/chantools /usr/local/bin/
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```
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### Compile from source
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If there isn't a pre-built binary for your operating system or architecture
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available or you want to build `chantools` from source for another reason, you
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need to make sure you have `go 1.16.x` (or later) and `make` installed and can
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then run the following commands:
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```bash
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git clone https://github.com/guggero/chantools.git
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cd chantools
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make install
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```
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## Channel recovery scenario
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The following flow chart shows the main recovery scenario this tool was built
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for. This scenario assumes that you do have access to the crashed node's seed,
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`channel.backup` file and some state of a `channel.db` file (perhaps from a
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file based backup or the recovered file from the crashed node).
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Following this guide will help you get your channel **funds** back! The channels
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themselves can't be restored to work normally unless step 1 is successful (
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compacting the DB).
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![rescue flow](doc/rescue-flow.png)
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**Explanation:**
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1. **Node crashed**: For some reason your `lnd` node crashed and isn't starting
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anymore. If you get errors similar to
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[this](https://github.com/lightningnetwork/lnd/issues/4449),
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[this](https://github.com/lightningnetwork/lnd/issues/3473) or
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[this](https://github.com/lightningnetwork/lnd/issues/4102), it is possible
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that a simple compaction (a full copy in safe mode) can solve your problem.
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See [`chantools compactdb`](doc/chantools_compactdb.md).
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<br/><br/>
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If that doesn't work and you need to continue the recovery, make sure you can
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at least extract the `channel.backup` file and if somehow possible any version
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of the `channel.db` from the node.
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<br/><br/>
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Whatever you do, do **never, ever** replace your `channel.db` file with an old
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version (from a file based backup) and start your node that way.
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[Read this explanation why that can lead to loss of funds.](https://github.com/lightningnetwork/lnd/blob/master/docs/safety.md#file-based-backups)
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2. **Rescue on-chain balance**: To start the recovery process, we are going to
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re-create the node from scratch. To make sure we don't overwrite any old data
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in the process, make sure the old data directory of your node (usually `.lnd`
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in the user's home directory) is safely moved away (or the whole folder
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renamed) before continuing.<br/>
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To start the on-chain recovery, [follow the sub step "Starting On-Chain Recovery" of this guide](https://github.com/lightningnetwork/lnd/blob/master/docs/recovery.md#starting-on-chain-recovery).
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Don't follow the whole guide, only this single chapter!
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<br/><br/>
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This step is completed once the `lncli getinfo` command shows both
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`"synced_to_chain": true` and `"synced_to_graph": true` which can take several
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hours depending on the speed of your hardware. **Do not be alarmed** that the
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`lncli getinfo` command shows 0 channels. This is normal as we haven't started
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the off-chain recovery yet.
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3. **Recover channels using SCB**: Now that the node is fully synced, we can try
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to recover the channels using the [Static Channel Backups (SCB)](https://github.com/lightningnetwork/lnd/blob/master/docs/safety.md#static-channel-backups-scbs).
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For this, you need a file called `channel.backup`. Simply run the command
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`lncli restorechanbackup --multi_file <path-to-your-channel.backup>`. **This
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will take a while!**. The command itself can take several minutes to complete,
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depending on the number of channels. The recovery can easily take a day or
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two as a lot of chain rescanning needs to happen. It is recommended to wait at
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least one full day. You can watch the progress with the `lncli pendingchannels`
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command. If the list is empty, congratulations, you've recovered all channels!
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If the list stays un-changed for several hours, it means not all channels
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could be restored using this method.
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[One explanation can be found here.](https://github.com/lightningnetwork/lnd/blob/master/docs/safety.md#zombie-channels)
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4. **Install chantools**: To try to recover the remaining channels, we are going
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to use `chantools`. Simply [follow the installation instructions.](#installation)
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The recovery can only be continued if you have access to some version of the
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crashed node's `channel.db`. This could be the latest state as recovered from
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the crashed file system, or a version from a regular file based backup. If you
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do not have any version of a channel DB, `chantools` won't be able to help
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with the recovery. See step 11 for some possible manual steps.
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5. **Create copy of channel DB**: To make sure we can read the channel DB, we
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are going to create a copy in safe mode (called compaction). Simply run
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<br/><br/>
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`chantools compactdb --sourcedb <recovered-channel.db> --destdb ./results/compacted.db`
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<br/><br/>
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We are going to assume that the compacted copy of the channel DB is located in
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`./results/compacted.db` in the following commands.
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6. **chantools summary**: First, `chantools` needs to find out the state of each
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channel on chain. For this, a blockchain API (by default [blockstream.info](https://blockstream.info))
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is queried. The result will be written to a file called
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`./results/summary-yyyy-mm-dd.json`. This result file will be needed for the
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next command.
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<br/><br/>
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`chantools --fromchanneldb ./results/compacted.db summary`
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7. **chantools rescueclosed**: It is possible that by now the remote peers have
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force-closed some of the remaining channels. What we now do is try to find the
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private keys to sweep our balance of those channels. For this we need a shared
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secret which is called the `commit_point` and is changed whenever a channel is
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updated. We do have the latest known version of this point in the channel DB.
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The following command tries to find all private keys for channels that have
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been closed by the other party. The command needs to know what channels it is
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operating on, so we have to supply the `summary-yyy-mm-dd.json` created by the
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previous command:
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<br/><br/>
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`chantools --fromsummary ./results/<summary-file-created-in-last-step>.json rescueclosed --channeldb ./results/compacted.db`
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<br/><br/>
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This will create a new file called `./results/rescueclosed-yyyy-mm-dd.json`
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which will contain any found private keys and will also be needed for the next
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command. Use `bitcoind` or Electrum Wallet to sweep all of the private keys.
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8. **chantools forceclose**: This command will now close all channels that
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`chantools` thinks are still open. This is achieved by publishing the latest
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known channel state of the `channel.db` file.
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<br/>**Please read the full warning text of the
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[`forceclose` command below](doc/chantools_forceclose.md) as this command can put
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your funds at risk** if the state in the channel DB is not the most recent
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one. This command should only be executed for channels where the remote peer
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is not online anymore.
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<br/><br/>
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`chantools --fromsummary ./results/<rescueclosed-file-created-in-last-step>.json forceclose --channeldb ./results/compacted.db --publish`
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<br/><br/>
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This will create a new file called `./results/forceclose-yyyy-mm-dd.json`
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which will be needed for the next command.
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<br/><br/>
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If you get the error `non-mandatory-script-verify-flag (Signature must be zero
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for failed CHECK(MULTI)SIG operation)`, you might be affected by an old bug
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of `lnd` that was fixed in the meantime. But it means the signature in the
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force-close transaction is invalid and needs to be fixed. There is [a guide
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on how to do exactly that here](doc/fix-commitment-tx.md).
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9. **Wait for timelocks**: The previous command closed the remaining open
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channels by publishing your node's state of the channel. By design of the
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Lightning Network, you now have to wait until the channel funds belonging to
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you are not time locked any longer. Depending on the size of the channel, you
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have to wait for somewhere between 144 and 2000 confirmations of the
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force-close transactions. Only continue with the next step after the channel
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with the highest `csv_delay` has reached that many confirmations of its
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closing transaction. You can check this by looking up each force closed
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channel transaction on a block explorer (like
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[blockstream.info](https://blockstream.info) for example). Open the result
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JSON file of the last command (`./results/forceclose-yyyy-mm-dd.json`) and
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look up every TXID in `"force_close" -> "txid"` on the explorer. If the number
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of confirmations is equal to or greater to the value shown in
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`"force_close" -> "csv_delay"` for each of the channels, you can proceed.
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10. **chantools sweeptimelock**: Once all force-close transactions have reached
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the number of transactions as the `csv_timeout` in the JSON demands, these
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time locked funds can now be swept. Use the following command to sweep all the
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channel funds to an address of your wallet:
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<br/><br/>
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`chantools --fromsummary ./results/<forceclose-file-created-in-last-step>.json sweeptimelock --publish --sweepaddr <bech32-address-from-your-wallet>`
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11. **Manual intervention necessary**: You got to this step because you either
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don't have a `channel.db` file or because `chantools` couldn't rescue all your
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node's channels. There are a few things you can try manually that have some
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chance of working:
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- Make sure you can connect to all nodes when restoring from SCB: It happens
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all the time that nodes change their IP addresses. When restoring from a
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static channel backup, your node tries to connect to the node using the IP
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address encoded in the backup file. If the address changed, the SCB restore
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process doesn't work. You can use block explorers like [1ml.com](https://1ml.com)
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to try to find an IP address that is up-to-date. Just run
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`lncli connect <node-pubkey>@<updated-ip-address>:<port>` in the recovered
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`lnd` node from step 3 and wait a few hours to see if the channel is now
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being force closed by the remote node.
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- Find out who the node belongs to: Maybe you opened the channel with someone
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you know. Or maybe their node alias contains some information about who the
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node belongs to. If you can find out who operates the remote node, you can
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ask them to force-close the channel from their end. If the channel was opened
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with the `option_static_remote_key`, (`lnd v0.8.0` and later), the funds can
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be swept by your node.
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12. **Use Zombie Channel Recovery Matcher**: As a final, last resort, you can
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go to [node-recovery.com](https://www.node-recovery.com/) and register your
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node's ID for being matched up against other nodes with the same problem.
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<br/><br/>
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Once you were contacted with a match, follow the instructions on the
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[Zombie Channel Recovery Guide](doc/zombierecovery.md) page.
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<br/><br/>
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If you know the peer of a zombie channel and have a way to contact them, you
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can also skip the registration/matching process and [create your own match
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file](doc/zombierecovery.md#file-format).
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## Seed and passphrase input
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All commands that require the seed (and, if set, the seed's passphrase) offer
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three distinct possibilities to specify it:
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1. **Enter manually on the terminal**: This is the safest option as it makes
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sure that the seed isn't stored in the terminal's command history.
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2. **Pass the extened master root key as parameter**: This is added as an option
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for users who don't have the full seed anymore, possibly because they used
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`lnd`'s `--noseedbackup` flag and extracted the `xprv` from the wallet
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database with the `walletinfo` command. Those users can specify the master
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root key by passing the `--rootkey` command line flag to each command that
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requires the seed.
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3. **Use environment variables**: This option makes it easy to automate usage of
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`chantools` by removing the need to type into the terminal. There are three
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environment variables that can be set to skip entering values through the
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terminal:
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- `AEZEED_MNEMONIC`: Specifies the 24 word `lnd` aezeed.
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- `AEZEED_PASSPHRASE`: Specifies the passphrase for the aezeed. If no
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passphrase was used during the creation of the seed, the special value
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`AEZEED_PASSPHRASE="-"` needs to be passed to indicate no passphrase
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should be used or read from the terminal.
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- `WALLET_PASSWORD`: Specifies the encryption password that is needed to
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access a `wallet.db` file. This is currently only used by the `walletinfo`
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command.
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Example using environment variables:
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```shell script
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# We add a space in front of each command to tell bash we don't want this
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# command stored in the history.
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$ export AEZEED_MNEMONIC="abandon able ... ... ..."
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# We didn't set a passphrase for this example seed, we need to indicate this by
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# passing in a single dash character.
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$ export AEZEED_PASSPHRASE="-"
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$ chantools showrootkey
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2020-10-29 20:22:42.329 [INF] CHAN: chantools version v0.6.0 commit v0.6.0-3
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Your BIP32 HD root key is: xprv9s21ZrQH1...
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```
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### Are my funds safe?
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Some commands require the seed. But your seed will never leave your computer.
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Most commands don't require an internet connection: you can and should
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run them on a computer with a firewall that blocks outgoing connections.
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## Command overview
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```text
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This tool provides helper functions that can be used rescue
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funds locked in lnd channels in case lnd itself cannot run properly anymore.
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Complete documentation is available at https://github.com/guggero/chantools/.
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Usage:
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chantools [command]
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Available Commands:
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chanbackup Create a channel.backup file from a channel database
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closepoolaccount Tries to close a Pool account that has expired
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compactdb Create a copy of a channel.db file in safe/read-only mode
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deletepayments Remove all (failed) payments from a channel DB
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derivekey Derive a key with a specific derivation path
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dropchannelgraph Remove all graph related data from a channel DB
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dumpbackup Dump the content of a channel.backup file
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dumpchannels Dump all channel information from an lnd channel database
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fakechanbackup Fake a channel backup file to attempt fund recovery
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filterbackup Filter an lnd channel.backup file and remove certain channels
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fixoldbackup Fixes an old channel.backup file that is affected by the lnd issue #3881 (unable to derive shachain root key)
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forceclose Force-close the last state that is in the channel.db provided
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genimportscript Generate a script containing the on-chain keys of an lnd wallet that can be imported into other software like bitcoind
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migratedb Apply all recent lnd channel database migrations
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removechannel Remove a single channel from the given channel DB
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rescueclosed Try finding the private keys for funds that are in outputs of remotely force-closed channels
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rescuefunding Rescue funds locked in a funding multisig output that never resulted in a proper channel; this is the command the initiator of the channel needs to run
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rescuetweakedkey Attempt to rescue funds locked in an address with a key that was affected by a specific bug in lnd
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showrootkey Extract and show the BIP32 HD root key from the 24 word lnd aezeed
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signrescuefunding Rescue funds locked in a funding multisig output that never resulted in a proper channel; this is the command the remote node (the non-initiator) of the channel needs to run
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summary Compile a summary about the current state of channels
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sweeptimelock Sweep the force-closed state after the time lock has expired
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sweeptimelockmanual Sweep the force-closed state of a single channel manually if only a channel backup file is available
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sweepremoteclosed Go through all the addresses that could have funds of channels that were force-closed by the remote party. A public block explorer is queried for each address and if any balance is found, all funds are swept to a given address
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triggerforceclose Connect to a peer and send a custom message to trigger a force close of the specified channel
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vanitygen Generate a seed with a custom lnd node identity public key that starts with the given prefix
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walletinfo Shows info about an lnd wallet.db file and optionally extracts the BIP32 HD root key
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zombierecovery Try rescuing funds stuck in channels with zombie nodes
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help Help about any command
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Flags:
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-h, --help help for chantools
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-r, --regtest Indicates if regtest parameters should be used
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-t, --testnet Indicates if testnet parameters should be used
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Use "chantools [command] --help" for more information about a command.
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```
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## Commands
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Detailed documentation for each sub command is available in the
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[docs](doc/chantools.md) folder.
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Quick access:
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+ [chanbackup](doc/chantools_chanbackup.md)
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+ [closepoolaccount](doc/chantools_closepoolaccount.md)
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+ [compactdb](doc/chantools_compactdb.md)
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+ [deletepayments](doc/chantools_deletepayments.md)
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+ [derivekey](doc/chantools_derivekey.md)
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+ [dropchannelgraph](doc/chantools_dropchannelgraph.md)
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+ [dumpbackup](doc/chantools_dumpbackup.md)
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+ [dumpchannels](doc/chantools_dumpchannels.md)
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+ [fakechanbackup](doc/chantools_fakechanbackup.md)
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+ [filterbackup](doc/chantools_filterbackup.md)
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+ [fixoldbackup](doc/chantools_fixoldbackup.md)
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+ [genimportscript](doc/chantools_genimportscript.md)
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+ [migratedb](doc/chantools_migratedb.md)
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+ [forceclose](doc/chantools_forceclose.md)
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+ [removechannel](doc/chantools_removechannel.md)
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+ [rescueclosed](doc/chantools_rescueclosed.md)
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+ [rescuefunding](doc/chantools_rescuefunding.md)
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+ [showrootkey](doc/chantools_showrootkey.md)
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+ [signrescuefunding](doc/chantools_signrescuefunding.md)
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+ [summary](doc/chantools_summary.md)
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+ [sweepremoteclosed](doc/chantools_sweepremoteclosed.md)
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+ [sweeptimelock](doc/chantools_sweeptimelock.md)
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+ [sweeptimelockmanual](doc/chantools_sweeptimelockmanual.md)
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+ [triggerforceclose](doc/chantools_triggerforceclose.md)
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+ [vanitygen](doc/chantools_vanitygen.md)
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+ [walletinfo](doc/chantools_walletinfo.md)
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+ [zombierecovery](doc/chantools_zombierecovery.md)
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