lnd.xprv/lncfg/config.go

100 lines
3.9 KiB
Go

package lncfg
import (
"os"
"os/user"
"path/filepath"
"strings"
)
const (
// DefaultConfigFilename is the default configuration file name lnd
// tries to load.
DefaultConfigFilename = "lnd.conf"
// DefaultMaxPendingChannels is the default maximum number of incoming
// pending channels permitted per peer.
DefaultMaxPendingChannels = 1
// DefaultIncomingBroadcastDelta defines the number of blocks before the
// expiry of an incoming htlc at which we force close the channel. We
// only go to chain if we also have the preimage to actually pull in the
// htlc. BOLT #2 suggests 7 blocks. We use a few more for extra safety.
// Within this window we need to get our sweep or 2nd level success tx
// confirmed, because after that the remote party is also able to claim
// the htlc using the timeout path.
DefaultIncomingBroadcastDelta = 10
// DefaultFinalCltvRejectDelta defines the number of blocks before the
// expiry of an incoming exit hop htlc at which we cancel it back
// immediately. It is an extra safety measure over the final cltv
// requirement as it is defined in the invoice. It ensures that we
// cancel back htlcs that, when held on to, may cause us to force close
// the channel because we enter the incoming broadcast window. Bolt #11
// suggests 9 blocks here. We use a few more for additional safety.
//
// There is still a small gap that remains between receiving the
// RevokeAndAck and canceling back. If a new block arrives within that
// window, we may still force close the channel. There is currently no
// way to reject an UpdateAddHtlc of which we already know that it will
// push us in the broadcast window.
DefaultFinalCltvRejectDelta = DefaultIncomingBroadcastDelta + 3
// DefaultOutgoingBroadcastDelta defines the number of blocks before the
// expiry of an outgoing htlc at which we force close the channel. We
// are not in a hurry to force close, because there is nothing to claim
// for us. We do need to time the htlc out, because there may be an
// incoming htlc that will time out too (albeit later). Bolt #2 suggests
// a value of -1 here, but we allow one block less to prevent potential
// confusion around the negative value. It means we force close the
// channel at exactly the htlc expiry height.
DefaultOutgoingBroadcastDelta = 0
// DefaultOutgoingCltvRejectDelta defines the number of blocks before
// the expiry of an outgoing htlc at which we don't want to offer it to
// the next peer anymore. If that happens, we cancel back the incoming
// htlc. This is to prevent the situation where we have an outstanding
// htlc that brings or will soon bring us inside the outgoing broadcast
// window and trigger us to force close the channel. Bolt #2 suggests a
// value of 0. We pad it a bit, to prevent a slow round trip to the next
// peer and a block arriving during that round trip to trigger force
// closure.
DefaultOutgoingCltvRejectDelta = DefaultOutgoingBroadcastDelta + 3
)
// CleanAndExpandPath expands environment variables and leading ~ in the
// passed path, cleans the result, and returns it.
// This function is taken from https://github.com/btcsuite/btcd
func CleanAndExpandPath(path string) string {
if path == "" {
return ""
}
// Expand initial ~ to OS specific home directory.
if strings.HasPrefix(path, "~") {
var homeDir string
u, err := user.Current()
if err == nil {
homeDir = u.HomeDir
} else {
homeDir = os.Getenv("HOME")
}
path = strings.Replace(path, "~", homeDir, 1)
}
// NOTE: The os.ExpandEnv doesn't work with Windows-style %VARIABLE%,
// but the variables can still be expanded via POSIX-style $VARIABLE.
return filepath.Clean(os.ExpandEnv(path))
}
// NormalizeNetwork returns the common name of a network type used to create
// file paths. This allows differently versioned networks to use the same path.
func NormalizeNetwork(network string) string {
if strings.HasPrefix(network, "testnet") {
return "testnet"
}
return network
}