Rename server to proxy

proxy/telegram.go

@@ -0,0 +1,40 @@
+package proxy
+
+import (
+	"net"
+	"time"
+
+	"github.com/juju/errors"
+)
+
+var telegramDCIPs = [5]string{
+	"149.154.175.50:443",
+	"149.154.167.51:443",
+	"149.154.175.100:443",
+	"149.154.167.91:443",
+	"149.154.171.5:443",
+}
+
+const telegramKeepAlive = 30 * time.Second
+
+func dialToTelegram(dcIdx int16, timeout time.Duration) (net.Conn, error) {
+	if dcIdx < 0 || dcIdx >= 5 {
+		return nil, errors.New("Incorrect DC IDX")
+	}
+
+	dialer := net.Dialer{Timeout: timeout}
+	rawConn, err := dialer.Dial("tcp", telegramDCIPs[dcIdx])
+	conn := rawConn.(*net.TCPConn)
+	if err != nil {
+		return nil, errors.Annotate(err, "Cannot dial")
+	}
+
+	if err := conn.SetKeepAlive(true); err != nil {
+		return nil, errors.Annotate(err, "Cannot establish keepalive connection")
+	}
+	if err := conn.SetKeepAlivePeriod(telegramKeepAlive); err != nil {
+		return nil, errors.Annotate(err, "Cannot set keepalive timeout")
+	}
+
+	return conn, nil
+}