findlostchannel: add new command to ask all nodes about a channel

cmd/chantools/findlostchannel.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/gogo/protobuf/jsonpb"
+	"github.com/lightninglabs/chantools/lnd"
+	"github.com/lightningnetwork/lnd/keychain"
+	"github.com/lightningnetwork/lnd/lnrpc"
+	"github.com/lightningnetwork/lnd/lnwire"
+	"github.com/spf13/cobra"
+)
+
+type findLostChannelCommand struct {
+	ChannelGraph string
+	ChannelPoint string
+
+	TorProxy string
+
+	ConnectTimeout time.Duration
+
+	rootKey *rootKey
+	cmd     *cobra.Command
+}
+
+func newFindLostChannelCommand() *cobra.Command {
+	cc := &findLostChannelCommand{}
+	cc.cmd = &cobra.Command{
+		Use:   "findlostchannel",
+		Short: "Try to find out what node a channel was made with",
+		Long: `Connects to _all_ nodes given in the graph file and 
+attempts to find out if the node has knowledge of the given channel.
+Can be used to try to recover funds if the peer is not known (because no 
+channel.backup was created).
+
+The graph.json file can be created with 'lncli describegraph > graph.json' on
+any node in the network.`,
+		Example: `chantools findlostchannel \
+	--channel_graph graph.json \
+	--channel_point abcdef01234...:x`,
+		RunE: cc.Execute,
+	}
+	cc.cmd.Flags().StringVar(
+		&cc.ChannelGraph, "channel_graph", "", "the channel graph "+
+			"file as a JSON file, containing all nodes and their "+
+			"network addresses of the network",
+	)
+	cc.cmd.Flags().StringVar(
+		&cc.ChannelPoint, "channel_point", "", "funding transaction "+
+			"outpoint of the channel to attempt to find the peer "+
+			"for (<txid>:<txindex>)",
+	)
+	cc.cmd.Flags().StringVar(
+		&cc.TorProxy, "torproxy", "", "SOCKS5 proxy to use for Tor "+
+			"connections (to .onion addresses)",
+	)
+	cc.cmd.Flags().DurationVar(
+		&cc.ConnectTimeout, "connect_timeout", time.Second*30, "time "+
+			"to wait for a connection to be established",
+	)
+	cc.rootKey = newRootKey(cc.cmd, "deriving the identity key")
+
+	return cc.cmd
+}
+
+func (c *findLostChannelCommand) Execute(_ *cobra.Command, _ []string) error {
+	extendedKey, err := c.rootKey.read()
+	if err != nil {
+		return fmt.Errorf("error reading root key: %w", err)
+	}
+
+	identityPath := lnd.IdentityPath(chainParams)
+	child, pubKey, _, err := lnd.DeriveKey(
+		extendedKey, identityPath, chainParams,
+	)
+	if err != nil {
+		return fmt.Errorf("could not derive identity key: %w", err)
+	}
+	identityPriv, err := child.ECPrivKey()
+	if err != nil {
+		return fmt.Errorf("could not get identity private key: %w", err)
+	}
+	identityECDH := &keychain.PrivKeyECDH{
+		PrivKey: identityPriv,
+	}
+
+	outPoint, err := parseOutPoint(c.ChannelPoint)
+	if err != nil {
+		return fmt.Errorf("error parsing channel point: %w", err)
+	}
+
+	graphBytes, err := os.ReadFile(c.ChannelGraph)
+	if err != nil {
+		return fmt.Errorf("error reading graph JSON file %s: "+
+			"%v", c.ChannelGraph, err)
+	}
+	graph := &lnrpc.ChannelGraph{}
+	err = jsonpb.UnmarshalString(string(graphBytes), graph)
+	if err != nil {
+		return fmt.Errorf("error parsing graph JSON: %w", err)
+	}
+
+	for idx := range graph.Nodes {
+		node := graph.Nodes[idx]
+		if node.PubKey == "" {
+			continue
+		}
+
+		for _, addr := range node.Addresses {
+			nodeAddr := fmt.Sprintf("%s@%s", node.PubKey, addr.Addr)
+			p, err := connectPeer(
+				nodeAddr, c.TorProxy, pubKey, identityECDH,
+				c.ConnectTimeout,
+			)
+			if err != nil {
+				log.Infof("Error with node %s: %v", node.PubKey,
+					err)
+				continue
+			}
+
+			channelID := lnwire.NewChanIDFromOutPoint(outPoint)
+
+			// Channel ID (32 byte) + u16 for the data length (which
+			// will be 0).
+			data := make([]byte, 34)
+			copy(data[:32], channelID[:])
+
+			log.Infof("Sending channel re-establish to peer to "+
+				"trigger force close of channel %v", outPoint)
+
+			err = p.SendMessageLazy(
+				true, &lnwire.ChannelReestablish{
+					ChanID: channelID,
+				},
+			)
+			if err != nil {
+				return err
+			}
+
+			// Continue with next node.
+			break
+		}
+	}
+
+	return nil
+}

cmd/chantools/root.go

@@ -110,6 +110,7 @@ func main() {
 		newDocCommand(),
 		newFakeChanBackupCommand(),
 		newFilterBackupCommand(),
+		newFindLostChannelCommand(),
 		newFixOldBackupCommand(),
 		newForceCloseCommand(),
 		newGenImportScriptCommand(),