lnwire: rename HTLCAddRequest to UpdateAddHTLC

lnwire/update_add_htlc.go

@@ -0,0 +1,157 @@
+package lnwire
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/roasbeef/btcd/wire"
+	"github.com/roasbeef/btcutil"
+)
+
+// OnionPacketSize is the size of the serialized Sphinx onion packet included
+// in each UpdateAddHTLC message.
+const OnionPacketSize = 1254
+
+// UpdateAddHTLC is the message sent by Alice to Bob when she wishes to add an
+// HTLC to his remote commitment transaction. In addition to information
+// detailing the value, the ID, expiry, and the onion blob is also included
+// which allows Bob to derive the next hop in the route. The HTLC added by this
+// message is to be added to the remote node's "pending" HTLC's.  A subsequent
+// CommitSig message will move the pending HTLC to the newly created commitment
+// transaction, marking them as "staged".
+type UpdateAddHTLC struct {
+	// ChannelPoint is the particular active channel that this
+	// UpdateAddHTLC is binded to.
+	ChannelPoint wire.OutPoint
+
+	// ID is the identification server for this HTLC. This value is
+	// explicitly included as it allows nodes to survive single-sided
+	// restarts. The ID value for this sides starts at zero, and increases
+	// with each offered HTLC.
+	ID uint64
+
+	// Expiry is the number of blocks after which this HTLC should expire.
+	// It is the receiver's duty to ensure that the outgoing HTLC has a
+	// sufficient expiry value to allow her to redeem the incoming HTLC.
+	Expiry uint32
+
+	// Amount is the amount of satoshis this HTLC is worth.
+	Amount btcutil.Amount
+
+	// PaymentHash is the payment hash to be included in the HTLC this
+	// request creates. The pre-image to this HTLC must be revelaed by the
+	// upstream peer in order to fully settle the HTLC.
+	PaymentHash [32]byte
+
+	// OnionBlob is the raw serialized mix header used to route an HTLC in
+	// a privacy-preserving manner. The mix header is defined currently to
+	// be parsed as a 4-tuple: (groupElement, routingInfo, headerMAC,
+	// body).  First the receiving node should use the groupElement, and
+	// its current onion key to derive a shared secret with the source.
+	// Once the shared secret has been derived, the headerMAC should be
+	// checked FIRST. Note that the MAC only covers the routingInfo field.
+	// If the MAC matches, and the shared secret is fresh, then the node
+	// should strip off a layer of encryption, exposing the next hop to be
+	// used in the subsequent UpdateAddHTLC message.
+	OnionBlob [OnionPacketSize]byte
+}
+
+// NewUpdateAddHTLC returns a new empty UpdateAddHTLC message.
+func NewUpdateAddHTLC() *UpdateAddHTLC {
+	return &UpdateAddHTLC{}
+}
+
+// A compile time check to ensure UpdateAddHTLC implements the lnwire.Message
+// interface.
+var _ Message = (*UpdateAddHTLC)(nil)
+
+// Decode deserializes a serialized UpdateAddHTLC message stored in the passed
+// io.Reader observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) Decode(r io.Reader, pver uint32) error {
+	// ChannelPoint(8)
+	// ID(4)
+	// Expiry(4)
+	// Amount(8)
+	// PaymentHash(32)
+	// OnionBlob(1254)
+	err := readElements(r,
+		&c.ChannelPoint,
+		&c.ID,
+		&c.Expiry,
+		&c.Amount,
+		c.PaymentHash[:],
+		c.OnionBlob[:],
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Encode serializes the target UpdateAddHTLC into the passed io.Writer observing
+// the protocol version specified.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) Encode(w io.Writer, pver uint32) error {
+	err := writeElements(w,
+		c.ChannelPoint,
+		c.ID,
+		c.Expiry,
+		c.Amount,
+		c.PaymentHash[:],
+		c.OnionBlob[:],
+	)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Command returns the integer uniquely identifying this message type on the
+// wire.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) Command() uint32 {
+	return CmdUpdateAddHTLC
+}
+
+// MaxPayloadLength returns the maximum allowed payload size for a UpdateAddHTLC
+// complete message observing the specified protocol version.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) MaxPayloadLength(uint32) uint32 {
+	// 1342
+	return 36 + 8 + 4 + 8 + 32 + 1254
+}
+
+// Validate performs any necessary sanity checks to ensure all fields present
+// on the UpdateAddHTLC are valid.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) Validate() error {
+	if c.Amount < 0 {
+		// While fees can be negative, it's too confusing to allow
+		// negative payments. Maybe for some wallets, but not this one!
+		return fmt.Errorf("Amount paid cannot be negative.")
+	}
+	// We're good!
+	return nil
+}
+
+// String returns the string representation of the target UpdateAddHTLC.
+//
+// This is part of the lnwire.Message interface.
+func (c *UpdateAddHTLC) String() string {
+	return fmt.Sprintf("\n--- Begin UpdateAddHTLC ---\n") +
+		fmt.Sprintf("ChannelPoint:\t%v\n", c.ChannelPoint) +
+		fmt.Sprintf("ID:\t%v\n", c.ID) +
+		fmt.Sprintf("Expiry:\t\t%d\n", c.Expiry) +
+		fmt.Sprintf("Amount\t\t%d\n", c.Amount) +
+		fmt.Sprintf("PaymentHash:\t\t%x\n", c.PaymentHash) +
+		fmt.Sprintf("OnionBlob:\t\t\t\t%x\n", c.OnionBlob) +
+		fmt.Sprintf("--- End UpdateAddHTLC ---\n")
+}