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routing/router: extract sessionKey generation

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We extract the session key such that we can later store it across
restarts.
This commit is contained in:
Johan T. Halseth 2019-05-16 15:27:29 +02:00
parent ec087a9f73
commit 5a8b892bb6
No known key found for this signature in database
GPG Key ID: 15BAADA29DA20D26
2 changed files with 20 additions and 13 deletions
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30
routing/router.go
View File

@ -1404,12 +1404,22 @@ func (r *ChannelRouter) FindRoute(source, target route.Vertex,
return route, nil
}
// generateNewSessionKey generates a new ephemeral private key to be used for a
// payment attempt.
func generateNewSessionKey() (*btcec.PrivateKey, error) {
// Generate a new random session key to ensure that we don't trigger
// any replay.
//
// TODO(roasbeef): add more sources of randomness?
return btcec.NewPrivateKey(btcec.S256())
}
// generateSphinxPacket generates then encodes a sphinx packet which encodes
// the onion route specified by the passed layer 3 route. The blob returned
// from this function can immediately be included within an HTLC add packet to
// be sent to the first hop within the route.
func generateSphinxPacket(rt *route.Route, paymentHash []byte) ([]byte,
*sphinx.Circuit, error) {
func generateSphinxPacket(rt *route.Route, paymentHash []byte,
sessionKey *btcec.PrivateKey) ([]byte, *sphinx.Circuit, error) {
// As a sanity check, we'll ensure that the set of hops has been
// properly filled in, otherwise, we won't actually be able to
@ -1433,15 +1443,6 @@ func generateSphinxPacket(rt *route.Route, paymentHash []byte) ([]byte,
}),
)
// Generate a new random session key to ensure that we don't trigger
// any replay.
//
// TODO(roasbeef): add more sources of randomness?
sessionKey, err := btcec.NewPrivateKey(btcec.S256())
if err != nil {
return nil, nil, err
}
// Next generate the onion routing packet which allows us to perform
// privacy preserving source routing across the network.
sphinxPacket, err := sphinx.NewOnionPacket(
@ -1677,11 +1678,16 @@ func (r *ChannelRouter) sendPaymentAttempt(paySession *paymentSession,
}),
)
// Generate a new key to be used for this attempt.
sessionKey, err := generateNewSessionKey()
if err != nil {
return [32]byte{}, true, err
}
// Generate the raw encoded sphinx packet to be included along
// with the htlcAdd message that we send directly to the
// switch.
onionBlob, circuit, err := generateSphinxPacket(
route, paymentHash[:],
route, paymentHash[:], sessionKey,
)
if err != nil {
return [32]byte{}, true, err

3
routing/router_test.go
View File

@ -2442,8 +2442,9 @@ func TestIsStaleEdgePolicy(t *testing.T) {
func TestEmptyRoutesGenerateSphinxPacket(t *testing.T) {
t.Parallel()
sessionKey, _ := btcec.NewPrivateKey(btcec.S256())
emptyRoute := &route.Route{}
_, _, err := generateSphinxPacket(emptyRoute, testHash[:])
_, _, err := generateSphinxPacket(emptyRoute, testHash[:], sessionKey)
if err != route.ErrNoRouteHopsProvided {
t.Fatalf("expected empty hops error: instead got: %v", err)
}