lnd.xprv/netann/node_announcement.go
2020-03-17 16:25:02 -07:00

61 lines
1.9 KiB
Go

package netann
import (
"net"
"time"
"github.com/btcsuite/btcd/btcec"
"github.com/lightningnetwork/lnd/lnwallet"
"github.com/lightningnetwork/lnd/lnwire"
)
// NodeAnnModifier is a closure that makes in-place modifications to an
// lnwire.NodeAnnouncement.
type NodeAnnModifier func(*lnwire.NodeAnnouncement)
// NodeAnnSetAddrs is a functional option that allows updating the addresses of
// the given node announcement.
func NodeAnnSetAddrs(addrs []net.Addr) func(*lnwire.NodeAnnouncement) {
return func(nodeAnn *lnwire.NodeAnnouncement) {
nodeAnn.Addresses = addrs
}
}
// NodeAnnSetTimestamp is a functional option that sets the timestamp of the
// announcement to the current time, or increments it if the timestamp is
// already in the future.
func NodeAnnSetTimestamp(nodeAnn *lnwire.NodeAnnouncement) {
newTimestamp := uint32(time.Now().Unix())
if newTimestamp <= nodeAnn.Timestamp {
// Increment the prior value to ensure the timestamp
// monotonically increases, otherwise the announcement won't
// propagate.
newTimestamp = nodeAnn.Timestamp + 1
}
nodeAnn.Timestamp = newTimestamp
}
// SignNodeAnnouncement applies the given modifies to the passed
// lnwire.NodeAnnouncement, then signs the resulting announcement. The provided
// update should be the most recent, valid update, otherwise the timestamp may
// not monotonically increase from the prior.
func SignNodeAnnouncement(signer lnwallet.MessageSigner,
pubKey *btcec.PublicKey, nodeAnn *lnwire.NodeAnnouncement,
mods ...NodeAnnModifier) error {
// Apply the requested changes to the node announcement.
for _, modifier := range mods {
modifier(nodeAnn)
}
// Create the DER-encoded ECDSA signature over the message digest.
sig, err := SignAnnouncement(signer, pubKey, nodeAnn)
if err != nil {
return err
}
// Parse the DER-encoded signature into a fixed-size 64-byte array.
nodeAnn.Signature, err = lnwire.NewSigFromSignature(sig)
return err
}