Add support for passive ICE TCP candidate

Closes #196

tcp_mux.go

@@ -0,0 +1,273 @@
+package ice
+
+import (
+	"encoding/binary"
+	"io"
+	"net"
+	"strings"
+	"sync"
+
+	"github.com/pion/logging"
+	"github.com/pion/stun"
+)
+
+type tcpMux struct {
+	params *tcpMuxParams
+
+	// conns is a map of all tcpPacketConns indexed by ufrag
+	conns map[string]*tcpPacketConn
+
+	mu         sync.Mutex
+	wg         sync.WaitGroup
+	closedChan chan struct{}
+	closeOnce  sync.Once
+}
+
+type tcpMuxParams struct {
+	Listener       net.Listener
+	Logger         logging.LeveledLogger
+	ReadBufferSize int
+}
+
+func newTCPMux(params tcpMuxParams) *tcpMux {
+	m := &tcpMux{
+		params: &params,
+
+		conns: map[string]*tcpPacketConn{},
+
+		closedChan: make(chan struct{}),
+	}
+
+	m.wg.Add(1)
+	go func() {
+		defer m.wg.Done()
+		m.start()
+	}()
+
+	return m
+}
+
+func (m *tcpMux) start() {
+	m.params.Logger.Infof("Listening TCP on %s\n", m.params.Listener.Addr())
+	for {
+		conn, err := m.params.Listener.Accept()
+		if err != nil {
+			m.params.Logger.Infof("Error accepting connection: %s\n", err)
+			return
+		}
+
+		m.params.Logger.Debugf("Accepted connection from: %s to %s", conn.RemoteAddr(), conn.LocalAddr())
+
+		m.wg.Add(1)
+		go func() {
+			defer m.wg.Done()
+			m.handleConn(conn)
+		}()
+	}
+}
+
+func (m *tcpMux) LocalAddr() net.Addr {
+	return m.params.Listener.Addr()
+}
+
+func (m *tcpMux) GetConn(ufrag string) (net.PacketConn, error) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	conn, ok := m.conns[ufrag]
+
+	if ok {
+		return conn, nil
+		// return nil, fmt.Errorf("duplicate ufrag %v", ufrag)
+	}
+
+	conn = m.createConn(ufrag, m.LocalAddr())
+
+	return conn, nil
+}
+
+func (m *tcpMux) createConn(ufrag string, localAddr net.Addr) *tcpPacketConn {
+	conn := newTCPPacketConn(tcpPacketParams{
+		ReadBuffer: m.params.ReadBufferSize,
+		LocalAddr:  localAddr,
+		Logger:     m.params.Logger,
+	})
+	m.conns[ufrag] = conn
+
+	m.wg.Add(1)
+	go func() {
+		defer m.wg.Done()
+		<-conn.CloseChannel()
+		m.RemoveConn(ufrag)
+	}()
+
+	return conn
+}
+
+func (m *tcpMux) closeAndLogError(closer io.Closer) {
+	err := closer.Close()
+	if err != nil {
+		m.params.Logger.Warnf("Error closing connection: %s", err)
+	}
+}
+
+func (m *tcpMux) handleConn(conn net.Conn) {
+	buf := make([]byte, receiveMTU)
+
+	n, err := readStreamingPacket(conn, buf)
+
+	if err != nil {
+		m.params.Logger.Warnf("Error reading first packet: %s", err)
+		return
+	}
+
+	buf = buf[:n]
+
+	msg := &stun.Message{
+		Raw: make([]byte, len(buf)),
+	}
+	// Explicitly copy raw buffer so Message can own the memory.
+	copy(msg.Raw, buf)
+	if err = msg.Decode(); err != nil {
+		m.closeAndLogError(conn)
+		m.params.Logger.Warnf("Failed to handle decode ICE from %s to %s: %v\n", conn.RemoteAddr(), conn.LocalAddr(), err)
+		return
+	}
+
+	if m == nil || msg.Type.Method != stun.MethodBinding { // not a stun
+		m.closeAndLogError(conn)
+		m.params.Logger.Warnf("Not a STUN message from %s to %s\n", conn.RemoteAddr(), conn.LocalAddr())
+		return
+	}
+
+	for _, attr := range msg.Attributes {
+		m.params.Logger.Debugf("msg attr: %s\n", attr.String())
+	}
+
+	// Firefox will send ICEControlling for its Active canddiate. We
+	// currently support passive local TCP candidates only.
+	//
+	// TODO: not sure what will be sent for caniddate with tcptype S-O.
+	_, err = msg.Get(stun.AttrICEControlling)
+	if err != nil {
+		m.closeAndLogError(conn)
+		m.params.Logger.Warnf("No ICEControlling attribute in STUN message from %s to %s\n", conn.RemoteAddr(), conn.LocalAddr())
+		return
+	}
+
+	attr, err := msg.Get(stun.AttrUsername)
+	if err != nil {
+		m.closeAndLogError(conn)
+		m.params.Logger.Warnf("No Username attribute in STUN message from %s to %s\n", conn.RemoteAddr(), conn.LocalAddr())
+		return
+	}
+
+	ufrag := strings.Split(string(attr), ":")[0]
+	m.params.Logger.Debugf("Ufrag: %s\n", ufrag)
+
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	packetConn, ok := m.conns[ufrag]
+	if !ok {
+		packetConn = m.createConn(ufrag, conn.LocalAddr())
+	}
+
+	if err := packetConn.AddConn(conn, buf); err != nil {
+		m.closeAndLogError(conn)
+		m.params.Logger.Warnf("Error adding conn to tcpPacketConn from %s to %s, %w\n", conn.RemoteAddr(), conn.LocalAddr(), err)
+		return
+	}
+}
+
+func (m *tcpMux) Close() error {
+	m.mu.Lock()
+
+	m.closeOnce.Do(func() {
+		close(m.closedChan)
+	})
+
+	m.conns = map[string]*tcpPacketConn{}
+	m.mu.Unlock()
+
+	err := m.params.Listener.Close()
+
+	m.wg.Wait()
+
+	return err
+}
+
+func (m *tcpMux) CloseChannel() <-chan struct{} {
+	return m.closedChan
+}
+
+func (m *tcpMux) RemoveConn(ufrag string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	if conn, ok := m.conns[ufrag]; ok {
+		m.closeAndLogError(conn)
+		delete(m.conns, ufrag)
+	}
+
+	if len(m.conns) == 0 {
+		m.closeOnce.Do(func() {
+			close(m.closedChan)
+		})
+
+		m.closeAndLogError(m.params.Listener)
+	}
+}
+
+const streamingPacketHeaderLen = 2
+
+// readStreamingPacket reads 1 packet from stream
+// read packet  bytes https://tools.ietf.org/html/rfc4571#section-2
+// 2-byte length header prepends each packet:
+//     0                   1                   2                   3
+//     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//    -----------------------------------------------------------------
+//    |             LENGTH            |  RTP or RTCP packet ...       |
+//    -----------------------------------------------------------------
+func readStreamingPacket(conn net.Conn, buf []byte) (int, error) {
+	var header = make([]byte, streamingPacketHeaderLen)
+	var bytesRead, n int
+	var err error
+
+	for bytesRead < streamingPacketHeaderLen {
+		if n, err = conn.Read(header[bytesRead:streamingPacketHeaderLen]); err != nil {
+			return 0, err
+		}
+		bytesRead += n
+	}
+
+	length := int(binary.BigEndian.Uint16(header))
+
+	if length > cap(buf) {
+		return length, io.ErrShortBuffer
+	}
+
+	bytesRead = 0
+	for bytesRead < length {
+		if n, err = conn.Read(buf[bytesRead:length]); err != nil {
+			return 0, err
+		}
+		bytesRead += n
+	}
+
+	return bytesRead, nil
+}
+
+func writeStreamingPacket(conn net.Conn, buf []byte) (int, error) {
+	bufferCopy := make([]byte, streamingPacketHeaderLen+len(buf))
+	binary.BigEndian.PutUint16(bufferCopy, uint16(len(buf)))
+	copy(bufferCopy[2:], buf)
+
+	n, err := conn.Write(bufferCopy)
+
+	if err != nil {
+		return 0, err
+	}
+
+	return n - streamingPacketHeaderLen, nil
+}