caddy/listen_linux.go

package caddy

import (
	"context"
	"net"
	"syscall"
	"time"

	"go.uber.org/zap"
	"golang.org/x/sys/unix"
)

// ListenTimeout is the same as Listen, but with a configurable keep-alive timeout duration.
func ListenTimeout(network, addr string, keepalivePeriod time.Duration) (net.Listener, error) {
	// check to see if plugin provides listener
	if ln, err := getListenerFromPlugin(network, addr); err != nil || ln != nil {
		return pipeable(ln), err
	}

	config := &net.ListenConfig{Control: reusePort, KeepAlive: keepalivePeriod}
	ln, err := config.Listen(context.Background(), network, addr)
	return pipeable(ln), err
}

func reusePort(network, address string, conn syscall.RawConn) error {
	return conn.Control(func(descriptor uintptr) {
		if err := unix.SetsockoptInt(int(descriptor), unix.SOL_SOCKET, unix.SO_REUSEPORT, 1); err != nil {
			Log().Error("setting SO_REUSEPORT",
				zap.String("network", network),
				zap.String("address", address),
				zap.Uintptr("descriptor", descriptor),
				zap.Error(err))
		}
	})
}