1 files changed, 79 insertions, 0 deletions
diff --git a/utils/network.go b/utils/network.go
new file mode 100755
index 00000000..e57854a8
--- /dev/null
+++ b/utils/network.go
@@ -0,0 +1,79 @@
+// +build linux darwin freebsd
+
+package utils
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"strings"
+	"syscall"
+
+	"github.com/valyala/tcplisten"
+)
+
+//   - SO_REUSEPORT. This option allows linear scaling server performance
+//     on multi-CPU servers.
+//     See https://www.nginx.com/blog/socket-sharding-nginx-release-1-9-1/ for details.
+//
+//   - TCP_DEFER_ACCEPT. This option expects the server reads from the accepted
+//     connection before writing to them.
+//
+//   - TCP_FASTOPEN. See https://lwn.net/Articles/508865/ for details.
+// CreateListener crates socket listener based on DSN definition.
+func CreateListener(address string) (net.Listener, error) {
+	dsn := strings.Split(address, "://")
+
+	switch len(dsn) {
+	case 1:
+		// assume, that there is no prefix here [127.0.0.1:8000]
+		return createTCPListener(dsn[0])
+	case 2:
+		// we got two part here, first part is the transport, second - address
+		// [tcp://127.0.0.1:8000] OR [unix:///path/to/unix.socket] OR [error://path]
+		// where error is wrong transport name
+		switch dsn[0] {
+		case "unix":
+			// check of file exist. If exist, unlink
+			if fileExists(dsn[1]) {
+				err := syscall.Unlink(dsn[1])
+				if err != nil {
+					return nil, fmt.Errorf("error during the unlink syscall: error %v", err)
+				}
+			}
+			return net.Listen(dsn[0], dsn[1])
+		case "tcp":
+			return createTCPListener(dsn[1])
+			// not an tcp or unix
+		default:
+			return nil, fmt.Errorf("invalid Protocol ([tcp://]:6001, unix://file.sock), address: %s", address)
+		}
+		// wrong number of split parts
+	default:
+		return nil, fmt.Errorf("wrong number of parsed protocol parts, address: %s", address)
+	}
+}
+
+func createTCPListener(addr string) (net.Listener, error) {
+	cfg := tcplisten.Config{
+		ReusePort:   true,
+		DeferAccept: true,
+		FastOpen:    true,
+		Backlog:     0,
+	}
+	listener, err := cfg.NewListener("tcp4", addr)
+	if err != nil {
+		return nil, err
+	}
+	return listener, nil
+}
+
+// fileExists checks if a file exists and is not a directory before we
+// try using it to prevent further errors.
+func fileExists(filename string) bool {
+	info, err := os.Stat(filename)
+	if os.IsNotExist(err) {
+		return false
+	}
+	return !info.IsDir()
+}