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watchtower/wtclient/backup_task: make sweep pkscript independent of session

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This commit changes when the sweep pkscript
is assigned in the construction of the justice
transaction. Currently, the sweep pkscript is
assigned when the task is bound to a session.
However, we will moving to an assignment where
a unique sweep pkscript is used per channel to
prevent address inflation. Hence, this commit
makes the sweep pkscript a state dependent
variable, since it can be known at the time the
channel id is assigned.
This commit is contained in:
Conner Fromknecht 2019-02-06 18:20:30 -08:00
parent fe9f703b5b
commit a00fc148c8
No known key found for this signature in database
GPG Key ID: E7D737B67FA592C7
2 changed files with 11 additions and 11 deletions
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14
watchtower/wtclient/backup_task.go
View File

@ -43,6 +43,7 @@ type backupTask struct {
toLocalInput input.Input
toRemoteInput input.Input
totalAmt btcutil.Amount
sweepPkScript []byte
// session-dependent variables
@ -53,7 +54,8 @@ type backupTask struct {
// newBackupTask initializes a new backupTask and populates all state-dependent
// variables.
func newBackupTask(chanID *lnwire.ChannelID,
breachInfo *lnwallet.BreachRetribution) *backupTask {
breachInfo *lnwallet.BreachRetribution,
sweepPkScript []byte) *backupTask {
// Parse the non-dust outputs from the breach transaction,
// simultaneously computing the total amount contained in the inputs
@ -100,6 +102,7 @@ func newBackupTask(chanID *lnwire.ChannelID,
toLocalInput: toLocalInput,
toRemoteInput: toRemoteInput,
totalAmt: btcutil.Amount(totalAmt),
sweepPkScript: sweepPkScript,
}
}
@ -122,8 +125,7 @@ func (t *backupTask) inputs() map[wire.OutPoint]input.Input {
// SessionInfo's policy. If no error is returned, the task has been bound to the
// session and can be queued to upload to the tower. Otherwise, the bind failed
// and should be rescheduled with a different session.
func (t *backupTask) bindSession(session *wtdb.SessionInfo,
sweepPkScript []byte) error {
func (t *backupTask) bindSession(session *wtdb.SessionInfo) error {
// First we'll begin by deriving a weight estimate for the justice
// transaction. The final weight can be different depending on whether
@ -152,7 +154,7 @@ func (t *backupTask) bindSession(session *wtdb.SessionInfo,
// in the current session's policy.
outputs, err := session.Policy.ComputeJusticeTxOuts(
t.totalAmt, int64(weightEstimate.Weight()),
sweepPkScript, session.RewardAddress,
t.sweepPkScript, session.RewardAddress,
)
if err != nil {
return err
@ -170,7 +172,7 @@ func (t *backupTask) bindSession(session *wtdb.SessionInfo,
// session-dependent variables, and signs the resulting transaction. The
// required pieces from signatures, witness scripts, etc are then packaged into
// a JusticeKit and encrypted using the breach transaction's key.
func (t *backupTask) craftSessionPayload(sweepPkScript []byte,
func (t *backupTask) craftSessionPayload(
signer input.Signer) (wtdb.BreachHint, []byte, error) {
var hint wtdb.BreachHint
@ -179,7 +181,7 @@ func (t *backupTask) craftSessionPayload(sweepPkScript []byte,
// to-local script, and the remote CSV delay.
keyRing := t.breachInfo.KeyRing
justiceKit := &blob.JusticeKit{
SweepAddress: sweepPkScript,
SweepAddress: t.sweepPkScript,
RevocationPubKey: toBlobPubKey(keyRing.RevocationKey),
LocalDelayPubKey: toBlobPubKey(keyRing.DelayKey),
CSVDelay: t.breachInfo.RemoteDelay,

8
watchtower/wtclient/backup_task_internal_test.go
View File

@ -397,7 +397,7 @@ func TestBackupTask(t *testing.T) {
func testBackupTask(t *testing.T, test backupTaskTest) {
// Create a new backupTask from the channel id and breach info.
task := newBackupTask(&test.chanID, test.breachInfo)
task := newBackupTask(&test.chanID, test.breachInfo, test.expSweepScript)
// Assert that all parameters set during initialization are properly
// populated.
@ -452,7 +452,7 @@ func testBackupTask(t *testing.T, test backupTaskTest) {
// Now, bind the session to the task. If successful, this locks in the
// session's negotiated parameters and allows the backup task to derive
// the final free variables in the justice transaction.
err := task.bindSession(test.session, test.expSweepScript)
err := task.bindSession(test.session)
if err != test.bindErr {
t.Fatalf("expected: %v when binding session, got: %v",
test.bindErr, err)
@ -509,9 +509,7 @@ func testBackupTask(t *testing.T, test backupTaskTest) {
// Now, we'll construct, sign, and encrypt the blob containing the parts
// needed to reconstruct the justice transaction.
hint, encBlob, err := task.craftSessionPayload(
test.expSweepScript, test.signer,
)
hint, encBlob, err := task.craftSessionPayload(test.signer)
if err != nil {
t.Fatalf("unable to craft session payload: %v", err)
}