lnd.xprv/discovery/utils.go

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package discovery
import (
"github.com/go-errors/errors"
"github.com/lightningnetwork/lnd/channeldb"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
"github.com/roasbeef/btcd/btcec"
)
// createChanAnnouncement is a helper function which creates all channel
// announcements given the necessary channel related database items. This
// function is used to transform out databse structs into the coresponding wire
// sturcts for announcing new channels to other peers, or simply syncing up a
// peer's initial routing table upon connect.
func createChanAnnouncement(chanProof *channeldb.ChannelAuthProof,
chanInfo *channeldb.ChannelEdgeInfo,
e1, e2 *channeldb.ChannelEdgePolicy) (*lnwire.ChannelAnnouncement,
*lnwire.ChannelUpdate, *lnwire.ChannelUpdate) {
// First, using the parameters of the channel, along with the channel
// authentication chanProof, we'll create re-create the original
// authenticated channel announcement.
chanID := lnwire.NewShortChanIDFromInt(chanInfo.ChannelID)
chanAnn := &lnwire.ChannelAnnouncement{
NodeSig1: chanProof.NodeSig1,
NodeSig2: chanProof.NodeSig2,
ShortChannelID: chanID,
BitcoinSig1: chanProof.BitcoinSig1,
BitcoinSig2: chanProof.BitcoinSig2,
NodeID1: chanInfo.NodeKey1,
NodeID2: chanInfo.NodeKey2,
BitcoinKey1: chanInfo.BitcoinKey1,
BitcoinKey2: chanInfo.BitcoinKey2,
}
// We'll unconditionally queue the channel's existence chanProof as it
// will need to be processed before either of the channel update
// networkMsgs.
// Since it's up to a node's policy as to whether they advertise the
// edge in dire direction, we don't create an advertisement if the edge
// is nil.
var edge1Ann, edge2Ann *lnwire.ChannelUpdate
if e1 != nil {
edge1Ann = &lnwire.ChannelUpdate{
Signature: e1.Signature,
ShortChannelID: chanID,
Timestamp: uint32(e1.LastUpdate.Unix()),
Flags: 0,
TimeLockDelta: e1.TimeLockDelta,
HtlcMinimumMsat: uint64(e1.MinHTLC),
BaseFee: uint32(e1.FeeBaseMSat),
FeeRate: uint32(e1.FeeProportionalMillionths),
}
}
if e2 != nil {
edge2Ann = &lnwire.ChannelUpdate{
Signature: e2.Signature,
ShortChannelID: chanID,
Timestamp: uint32(e2.LastUpdate.Unix()),
Flags: 1,
TimeLockDelta: e2.TimeLockDelta,
HtlcMinimumMsat: uint64(e2.MinHTLC),
BaseFee: uint32(e2.FeeBaseMSat),
FeeRate: uint32(e2.FeeProportionalMillionths),
}
}
return chanAnn, edge1Ann, edge2Ann
}
// copyPubKey performs a copy of the target public key, setting a fresh curve
// parameter during the process.
func copyPubKey(pub *btcec.PublicKey) *btcec.PublicKey {
return &btcec.PublicKey{
Curve: btcec.S256(),
X: pub.X,
Y: pub.Y,
}
}
// SignAnnouncement is a helper function which is used to sign any outgoing
// channel node node announcement messages.
func SignAnnouncement(signer lnwallet.MessageSigner, pubKey *btcec.PublicKey,
msg lnwire.Message) (*btcec.Signature, error) {
var (
data []byte
err error
)
switch m := msg.(type) {
case *lnwire.ChannelAnnouncement:
data, err = m.DataToSign()
case *lnwire.ChannelUpdate:
data, err = m.DataToSign()
case *lnwire.NodeAnnouncement:
data, err = m.DataToSign()
default:
return nil, errors.New("can't sign message " +
"of this format")
}
if err != nil {
return nil, errors.Errorf("unable to get data to sign: %v", err)
}
return signer.SignMessage(pubKey, data)
}