Maint: split Go files in dns package

internal/dns/setup.go

@@ -0,0 +1,58 @@
+package dns
+
+import (
+	"context"
+	"errors"
+	"net"
+
+	"github.com/qdm12/dns/pkg/check"
+	"github.com/qdm12/dns/pkg/nameserver"
+)
+
+var errUpdateFiles = errors.New("cannot update files")
+
+// Returning cancel == nil signals we want to re-run setupUnbound
+// Returning err == errUpdateFiles signals we should not fall back
+// on the plaintext DNS as DOT is still up and running.
+func (l *looper) setupUnbound(ctx context.Context) (
+	cancel context.CancelFunc, waitError chan error, closeStreams func(), err error) {
+	err = l.updateFiles(ctx)
+	if err != nil {
+		return nil, nil, nil, errUpdateFiles
+	}
+
+	settings := l.GetSettings()
+
+	unboundCtx, cancel := context.WithCancel(context.Background())
+	stdoutLines, stderrLines, waitError, err := l.conf.Start(unboundCtx, settings.Unbound.VerbosityDetailsLevel)
+	if err != nil {
+		cancel()
+		return nil, nil, nil, err
+	}
+
+	collectLinesDone := make(chan struct{})
+	go l.collectLines(stdoutLines, stderrLines, collectLinesDone)
+	closeStreams = func() {
+		close(stdoutLines)
+		close(stderrLines)
+		<-collectLinesDone
+	}
+
+	// use Unbound
+	nameserver.UseDNSInternally(net.IP{127, 0, 0, 1})
+	err = nameserver.UseDNSSystemWide(l.resolvConf, net.IP{127, 0, 0, 1},
+		settings.KeepNameserver)
+	if err != nil {
+		l.logger.Error(err.Error())
+	}
+
+	if err := check.WaitForDNS(ctx, net.DefaultResolver); err != nil {
+		cancel()
+		<-waitError
+		close(waitError)
+		closeStreams()
+		return nil, nil, nil, err
+	}
+
+	return cancel, waitError, closeStreams, nil
+}