mirror of
https://github.com/tladesignz/dnstt.git
synced 2026-09-28 18:07:56 +03:00
Factor out a pattern for different kinds of remote address.
This commit is contained in:
David Fifield
+85
-57
@@ -149,62 +149,45 @@ func dnsNameCapacity(domain dns.Name) int {
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return capacity
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}
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func run(domain dns.Name, localAddr, udpAddr string) error {
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var sess *smux.Session
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func run(domain dns.Name, localAddr *net.TCPAddr, remoteAddr net.Addr, pconn net.PacketConn) error {
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defer pconn.Close()
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if udpAddr != "" {
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addr, err := net.ResolveUDPAddr("udp", udpAddr)
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if err != nil {
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return err
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}
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udpConn, err := net.ListenUDP("udp", nil)
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if err != nil {
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return fmt.Errorf("opening UDP conn: %v", err)
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}
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defer udpConn.Close()
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// Start up the virtual PacketConn for turbotunnel.
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pconn := NewUDPPacketConn(udpConn, addr, domain)
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// Open a KCP conn on the PacketConn.
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conn, err := kcp.NewConn2(addr, nil, 0, 0, pconn)
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if err != nil {
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return fmt.Errorf("opening KCP conn: %v", err)
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}
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defer conn.Close()
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// Permit coalescing the payloads of consecutive sends.
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conn.SetStreamMode(true)
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// Disable the dynamic congestion window (limit only by the
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// maximum of local and remote static windows).
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conn.SetNoDelay(
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0, // default nodelay
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0, // default interval
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0, // default resend
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1, // nc=1 => congestion window off
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)
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mtu := dnsNameCapacity(domain) - 8 - 1 - numPadding - 1 // clientid + padding length prefix + padding + data length prefix
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if mtu < 80 {
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return fmt.Errorf("domain %s leaves only %d bytes for payload", domain, mtu)
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}
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log.Printf("MTU %d\n", mtu)
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if rc := conn.SetMtu(mtu); !rc {
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panic(rc)
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}
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// Start a smux session on the KCP conn.
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smuxConfig := smux.DefaultConfig()
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smuxConfig.Version = 2
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smuxConfig.KeepAliveTimeout = idleTimeout
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sess, err = smux.Client(conn, smuxConfig)
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if err != nil {
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return fmt.Errorf("opening smux session: %v", err)
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}
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defer sess.Close()
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} else {
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return fmt.Errorf("need a UDP address")
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// Open a KCP conn on the PacketConn.
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conn, err := kcp.NewConn2(remoteAddr, nil, 0, 0, pconn)
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if err != nil {
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return fmt.Errorf("opening KCP conn: %v", err)
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}
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defer conn.Close()
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// Permit coalescing the payloads of consecutive sends.
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conn.SetStreamMode(true)
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// Disable the dynamic congestion window (limit only by the
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// maximum of local and remote static windows).
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conn.SetNoDelay(
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0, // default nodelay
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0, // default interval
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0, // default resend
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1, // nc=1 => congestion window off
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)
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mtu := dnsNameCapacity(domain) - 8 - 1 - numPadding - 1 // clientid + padding length prefix + padding + data length prefix
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if mtu < 80 {
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return fmt.Errorf("domain %s leaves only %d bytes for payload", domain, mtu)
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}
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log.Printf("MTU %d\n", mtu)
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if rc := conn.SetMtu(mtu); !rc {
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panic(rc)
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}
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ln, err := net.Listen("tcp", localAddr)
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// Start a smux session on the KCP conn.
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smuxConfig := smux.DefaultConfig()
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smuxConfig.Version = 2
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smuxConfig.KeepAliveTimeout = idleTimeout
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sess, err := smux.Client(conn, smuxConfig)
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if err != nil {
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return fmt.Errorf("opening smux session: %v", err)
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}
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defer sess.Close()
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ln, err := net.ListenTCP("tcp", localAddr)
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if err != nil {
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return fmt.Errorf("opening local listener: %v", err)
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}
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@@ -234,7 +217,7 @@ func main() {
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fmt.Fprintf(flag.CommandLine.Output(), "Usage: %s -udp ADDR DOMAIN LOCALADDR\n", os.Args[0])
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flag.PrintDefaults()
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}
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flag.StringVar(&udpAddr, "udp", "", "UDP port of DNS server")
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flag.StringVar(&udpAddr, "udp", "", "address of UDP DNS resolver")
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flag.Parse()
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log.SetFlags(log.LstdFlags | log.LUTC)
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@@ -245,12 +228,57 @@ func main() {
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}
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domain, err := dns.ParseName(flag.Arg(0))
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if err != nil {
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log.Printf("invalid domain %+q: %v\n", flag.Arg(0), err)
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fmt.Fprintf(os.Stderr, "invalid domain %+q: %v\n", flag.Arg(0), err)
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os.Exit(1)
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}
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localAddr, err := net.ResolveTCPAddr("tcp", flag.Arg(1))
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if err != nil {
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fmt.Fprintln(os.Stderr, err)
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os.Exit(1)
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}
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localAddr := flag.Arg(1)
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err = run(domain, localAddr, udpAddr)
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// Iterate over the remote resolver address options and select one and
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// only one.
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var remoteAddr net.Addr
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var pconn net.PacketConn
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for _, opt := range []struct {
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s string
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f func(string) (net.Addr, net.PacketConn, error)
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}{
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// -udp
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{udpAddr, func(s string) (net.Addr, net.PacketConn, error) {
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addr, err := net.ResolveUDPAddr("udp", s)
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if err != nil {
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return nil, nil, err
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}
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udpConn, err := net.ListenUDP("udp", nil)
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if err != nil {
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return nil, nil, err
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}
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return addr, NewUDPPacketConn(udpConn, addr, domain), nil
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}},
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} {
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if opt.s == "" {
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continue
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}
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if pconn != nil {
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fmt.Fprintf(os.Stderr, "the -udp option may be given only once\n")
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os.Exit(1)
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}
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a, c, err := opt.f(opt.s)
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if err != nil {
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fmt.Fprintln(os.Stderr, err)
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os.Exit(1)
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}
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remoteAddr = a
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pconn = c
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}
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if pconn == nil {
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fmt.Fprintf(os.Stderr, "the -udp option is required\n")
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os.Exit(1)
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}
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err = run(domain, localAddr, remoteAddr, pconn)
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if err != nil {
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log.Fatal(err)
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}
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