package adapter import ( "context" "net" E "github.com/sagernet/sing/common/exceptions" M "github.com/sagernet/sing/common/metadata" N "github.com/sagernet/sing/common/network" ) type ( ConnectionHandlerFunc = func(ctx context.Context, conn net.Conn, metadata InboundContext) error PacketConnectionHandlerFunc = func(ctx context.Context, conn N.PacketConn, metadata InboundContext) error ) func NewUpstreamHandler( metadata InboundContext, connectionHandler ConnectionHandlerFunc, packetHandler PacketConnectionHandlerFunc, errorHandler E.Handler, ) UpstreamHandlerAdapter { return &myUpstreamHandlerWrapper{ metadata: metadata, connectionHandler: connectionHandler, packetHandler: packetHandler, errorHandler: errorHandler, } } var _ UpstreamHandlerAdapter = (*myUpstreamHandlerWrapper)(nil) type myUpstreamHandlerWrapper struct { metadata InboundContext connectionHandler ConnectionHandlerFunc packetHandler PacketConnectionHandlerFunc errorHandler E.Handler } func (w *myUpstreamHandlerWrapper) NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error { w.metadata.Destination = metadata.Destination return w.connectionHandler(ctx, conn, w.metadata) } func (w *myUpstreamHandlerWrapper) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata M.Metadata) error { w.metadata.Destination = metadata.Destination return w.packetHandler(ctx, conn, w.metadata) } func (w *myUpstreamHandlerWrapper) NewError(ctx context.Context, err error) { w.errorHandler.NewError(ctx, err) } func UpstreamMetadata(metadata InboundContext) M.Metadata { return M.Metadata{ Source: metadata.Source, Destination: metadata.Destination, } } type myUpstreamContextHandlerWrapper struct { connectionHandler ConnectionHandlerFunc packetHandler PacketConnectionHandlerFunc errorHandler E.Handler } func NewUpstreamContextHandler( connectionHandler ConnectionHandlerFunc, packetHandler PacketConnectionHandlerFunc, errorHandler E.Handler, ) UpstreamHandlerAdapter { return &myUpstreamContextHandlerWrapper{ connectionHandler: connectionHandler, packetHandler: packetHandler, errorHandler: errorHandler, } } func (w *myUpstreamContextHandlerWrapper) NewConnection(ctx context.Context, conn net.Conn, metadata M.Metadata) error { myMetadata := ContextFrom(ctx) myMetadata.Destination = metadata.Destination return w.connectionHandler(ctx, conn, *myMetadata) } func (w *myUpstreamContextHandlerWrapper) NewPacketConnection(ctx context.Context, conn N.PacketConn, metadata M.Metadata) error { myMetadata := ContextFrom(ctx) myMetadata.Destination = metadata.Destination return w.packetHandler(ctx, conn, *myMetadata) } func (w *myUpstreamContextHandlerWrapper) NewError(ctx context.Context, err error) { w.errorHandler.NewError(ctx, err) }