add TCPConn type

internet/tcpconn.go

@@ -0,0 +1,158 @@
+package internet
+
+import (
+	"bytes"
+	"errors"
+	"log/slog"
+	"net/netip"
+	"time"
+
+	"github.com/soypat/lneto/ipv4"
+	"github.com/soypat/lneto/ipv6"
+	"github.com/soypat/lneto/tcp"
+)
+
+type TCPConn struct {
+	h          tcp.Handler
+	remoteAddr []byte
+	logger
+
+	rdead  time.Time
+	wdead  time.Time
+	lastTx time.Time
+	lastRx time.Time
+}
+type TCPConnConfig struct {
+	RxBuf             []byte
+	TxBuf             []byte
+	TxPacketQueueSize int
+	Logger            *slog.Logger
+}
+
+func (conn *TCPConn) Configure(config *TCPConnConfig) (err error) {
+	err = conn.h.SetBuffers(config.TxBuf, config.RxBuf, config.TxPacketQueueSize)
+	if err != nil {
+		return err
+	}
+	conn.logger.log = config.Logger
+	return nil
+}
+
+// LocalPort returns the local port on which the socket is listening or connected to.
+func (conn *TCPConn) LocalPort() uint16 { return conn.h.LocalPort() }
+
+// RemotePort returns the port of the incoming remote connection. Is non-zero if connection is established.
+func (conn *TCPConn) RemotePort() uint16 { return conn.h.RemotePort() }
+
+// State returns the TCP state of the socket.
+func (conn *TCPConn) State() tcp.State { return conn.h.State() }
+
+// BufferedInput returns the number of bytes in the socket's receive/input buffer.
+func (conn *TCPConn) BufferedInput() int { return conn.h.BufferedInput() }
+
+// OpenActive opens a connection to a remote peer with a known IP address and port combination.
+// iss is the initial send sequence number which is ideally a random number which is far away from the last sequence number used on a connection to the same host.
+func (conn *TCPConn) OpenActive(remote netip.AddrPort, localPort uint16, iss tcp.Value) error {
+	err := conn.h.OpenActive(localPort, remote.Port(), iss)
+	if err != nil {
+		return err
+	}
+	conn.reset(conn.h)
+	raddr := remote.Addr()
+	if raddr.Is4() {
+		addr4 := raddr.As4()
+		conn.remoteAddr = append(conn.remoteAddr[:0], addr4[:]...)
+	} else if raddr.Is6() {
+		addr6 := raddr.As16()
+		conn.remoteAddr = append(conn.remoteAddr[:0], addr6[:]...)
+	}
+	return nil
+}
+
+// OpenListen opens a passive connection which listens for the first SYN packet to be received on a local port.
+// iss is the initial send sequence number which is usually a randomly chosen number.
+func (conn *TCPConn) OpenListen(localPort uint16, iss tcp.Value) error {
+	err := conn.h.OpenListen(localPort, iss)
+	if err != nil {
+		return err
+	}
+	conn.reset(conn.h)
+	return nil
+}
+
+func (conn *TCPConn) RecvIP(buf []byte, off int) (err error) {
+	conn.trace("tcpconn.Recv:start")
+	if off >= len(buf) {
+		return errors.New("bad offset in TCPConn.Recv")
+	}
+	raddr, err := getIPAddr(buf[:off])
+	if err != nil {
+		return err
+	}
+	if conn.isRaddrSet() && !bytes.Equal(conn.remoteAddr, raddr) {
+		return errors.New("IP addr mismatch on TCPConn")
+	}
+	err = conn.h.Recv(buf[off:])
+	if err != nil {
+		return err
+	}
+	if !conn.isRaddrSet() && conn.h.RemotePort() != 0 {
+		conn.remoteAddr = append(conn.remoteAddr[:0], raddr...)
+	}
+	return nil
+}
+
+func (conn *TCPConn) HandleIP(buf []byte, off int) (n int, err error) {
+	if len(conn.remoteAddr) == 0 {
+		return 0, errors.New("unset IP address")
+	}
+	raddr, err := getIPAddr(buf[:off])
+	if err != nil {
+		return 0, err
+	} else if len(raddr) != len(conn.remoteAddr) {
+		return 0, errors.New("mismatched IP version")
+	}
+	n, err = conn.h.Send(buf[off:])
+	if err != nil {
+		return 0, err
+	}
+	copy(raddr, conn.remoteAddr)
+	return n, nil
+}
+
+func (conn *TCPConn) Send(response []byte) (n int, err error) {
+	conn.trace("tcpconn.Send:start")
+	return conn.h.Send(response)
+}
+
+func getIPAddr(buf []byte) (addr []byte, err error) {
+	switch buf[0] >> 4 {
+	case 4:
+		ifrm4, err := ipv4.NewFrame(buf)
+		if err != nil {
+			return addr, err
+		}
+		addr = ifrm4.SourceAddr()[:]
+	case 6:
+		ifrm6, err := ipv6.NewFrame(buf)
+		if err != nil {
+			return addr, err
+		}
+		addr = ifrm6.SourceAddr()[:]
+	default:
+		err = errors.New("unsupported IP version")
+	}
+	return addr, err
+}
+
+func (conn *TCPConn) isRaddrSet() bool {
+	return len(conn.remoteAddr) != 0
+}
+
+func (conn *TCPConn) reset(h tcp.Handler) {
+	*conn = TCPConn{
+		h:          h,
+		remoteAddr: conn.remoteAddr[:0],
+		logger:     conn.logger,
+	}
+}