watchtower/server/interface: adds Server, Peer and DB

watchtower/server/interface.go

@@ -0,0 +1,66 @@
+package server
+
+import (
+	"io"
+	"net"
+	"time"
+
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/lightningnetwork/lnd/watchtower/wtdb"
+)
+
+// Interface represents a simple, listen-only service that accepts watchtower
+// clients, and provides responses to their requests.
+type Interface interface {
+	// InboundPeerConnected accepts a new watchtower client, and handles any
+	// requests sent by the peer.
+	InboundPeerConnected(Peer)
+
+	// Start sets up the watchtower server.
+	Start() error
+
+	// Stop cleans up the watchtower's current connections and resources.
+	Stop() error
+}
+
+// Peer is the primary interface used to abstract watchtower clients.
+type Peer interface {
+	io.WriteCloser
+
+	// ReadNextMessage pulls the next framed message from the client.
+	ReadNextMessage() ([]byte, error)
+
+	// SetWriteDeadline specifies the time by which the client must have
+	// read a message sent by the server. In practice, the connection is
+	// buffered, so the client must read enough from the connection to
+	// support the server adding another reply.
+	SetWriteDeadline(time.Time) error
+
+	// SetReadDeadline specifies the time by which the client must send
+	// another message.
+	SetReadDeadline(time.Time) error
+
+	// RemotePub returns the client's public key.
+	RemotePub() *btcec.PublicKey
+
+	// RemoteAddr returns the client's network address.
+	RemoteAddr() net.Addr
+}
+
+// DB provides the server access to session creation and retrieval, as well as
+// persisting state updates sent by clients.
+type DB interface {
+	// InsertSessionInfo saves a newly agreed-upon session from a client.
+	// This method should fail if a session with the same session id already
+	// exists.
+	InsertSessionInfo(*wtdb.SessionInfo) error
+
+	// GetSessionInfo retrieves the SessionInfo associated with the session
+	// id, if it exists.
+	GetSessionInfo(*wtdb.SessionID) (*wtdb.SessionInfo, error)
+
+	// InsertStateUpdate persists a state update sent by a client, and
+	// validates the update against the current SessionInfo stored under the
+	// update's session id..
+	InsertStateUpdate(*wtdb.SessionStateUpdate) (uint16, error)
+}