cloudflared-mirror/tunneldns/tunnel.go

207 lines
5.5 KiB
Go

package tunneldns
import (
"net"
"os"
"os/signal"
"strconv"
"sync"
"syscall"
"github.com/cloudflare/cloudflared/cmd/cloudflared/cliutil"
"github.com/cloudflare/cloudflared/logger"
"github.com/cloudflare/cloudflared/metrics"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/cache"
"github.com/pkg/errors"
"github.com/rs/zerolog"
"github.com/urfave/cli/v2"
)
const (
LogFieldAddress = "address"
LogFieldURL = "url"
)
// Listener is an adapter between CoreDNS server and Warp runnable
type Listener struct {
server *dnsserver.Server
wg sync.WaitGroup
log *zerolog.Logger
}
func Command(hidden bool) *cli.Command {
return &cli.Command{
Name: "proxy-dns",
Action: cliutil.ErrorHandler(Run),
Usage: "Run a DNS over HTTPS proxy server.",
Flags: []cli.Flag{
&cli.StringFlag{
Name: "metrics",
Value: "localhost:",
Usage: "Listen address for metrics reporting.",
EnvVars: []string{"TUNNEL_METRICS"},
},
&cli.StringFlag{
Name: "address",
Usage: "Listen address for the DNS over HTTPS proxy server.",
Value: "localhost",
EnvVars: []string{"TUNNEL_DNS_ADDRESS"},
},
// Note TUN-3758 , we use Int because UInt is not supported with altsrc
&cli.IntFlag{
Name: "port",
Usage: "Listen on given port for the DNS over HTTPS proxy server.",
Value: 53,
EnvVars: []string{"TUNNEL_DNS_PORT"},
},
&cli.StringSliceFlag{
Name: "upstream",
Usage: "Upstream endpoint URL, you can specify multiple endpoints for redundancy.",
Value: cli.NewStringSlice("https://1.1.1.1/dns-query", "https://1.0.0.1/dns-query"),
EnvVars: []string{"TUNNEL_DNS_UPSTREAM"},
},
&cli.StringSliceFlag{
Name: "bootstrap",
Usage: "bootstrap endpoint URL, you can specify multiple endpoints for redundancy.",
Value: cli.NewStringSlice("https://162.159.36.1/dns-query", "https://162.159.46.1/dns-query", "https://[2606:4700:4700::1111]/dns-query", "https://[2606:4700:4700::1001]/dns-query"),
EnvVars: []string{"TUNNEL_DNS_BOOTSTRAP"},
},
},
ArgsUsage: " ", // can't be the empty string or we get the default output
Hidden: hidden,
}
}
// Run implements a foreground runner
func Run(c *cli.Context) error {
log := logger.CreateLoggerFromContext(c, logger.EnableTerminalLog)
metricsListener, err := net.Listen("tcp", c.String("metrics"))
if err != nil {
log.Fatal().Err(err).Msg("Failed to open the metrics listener")
}
go metrics.ServeMetrics(metricsListener, nil, nil, log)
listener, err := CreateListener(
c.String("address"),
// Note TUN-3758 , we use Int because UInt is not supported with altsrc
uint16(c.Int("port")),
c.StringSlice("upstream"),
c.StringSlice("bootstrap"),
log,
)
if err != nil {
log.Err(err).Msg("Failed to create the listeners")
return err
}
// Try to start the server
readySignal := make(chan struct{})
err = listener.Start(readySignal)
if err != nil {
log.Err(err).Msg("Failed to start the listeners")
return listener.Stop()
}
<-readySignal
// Wait for signal
signals := make(chan os.Signal, 10)
signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
defer signal.Stop(signals)
<-signals
// Shut down server
err = listener.Stop()
if err != nil {
log.Err(err).Msg("failed to stop")
}
return err
}
// Create a CoreDNS server plugin from configuration
func createConfig(address string, port uint16, p plugin.Handler) *dnsserver.Config {
c := &dnsserver.Config{
Zone: ".",
Transport: "dns",
ListenHosts: []string{address},
Port: strconv.FormatUint(uint64(port), 10),
}
c.AddPlugin(func(next plugin.Handler) plugin.Handler { return p })
return c
}
// Start blocks for serving requests
func (l *Listener) Start(readySignal chan struct{}) error {
defer close(readySignal)
l.log.Info().Str(LogFieldAddress, l.server.Address()).Msg("Starting DNS over HTTPS proxy server")
// Start UDP listener
if udp, err := l.server.ListenPacket(); err == nil {
l.wg.Add(1)
go func() {
_ = l.server.ServePacket(udp)
l.wg.Done()
}()
} else {
return errors.Wrap(err, "failed to create a UDP listener")
}
// Start TCP listener
tcp, err := l.server.Listen()
if err == nil {
l.wg.Add(1)
go func() {
_ = l.server.Serve(tcp)
l.wg.Done()
}()
}
return errors.Wrap(err, "failed to create a TCP listener")
}
// Stop signals server shutdown and blocks until completed
func (l *Listener) Stop() error {
if err := l.server.Stop(); err != nil {
return err
}
l.wg.Wait()
return nil
}
// CreateListener configures the server and bound sockets
func CreateListener(address string, port uint16, upstreams []string, bootstraps []string, log *zerolog.Logger) (*Listener, error) {
// Build the list of upstreams
upstreamList := make([]Upstream, 0)
for _, url := range upstreams {
log.Info().Str(LogFieldURL, url).Msg("Adding DNS upstream")
upstream, err := NewUpstreamHTTPS(url, bootstraps, log)
if err != nil {
return nil, errors.Wrap(err, "failed to create HTTPS upstream")
}
upstreamList = append(upstreamList, upstream)
}
// Create a local cache with HTTPS proxy plugin
chain := cache.New()
chain.Next = ProxyPlugin{
Upstreams: upstreamList,
}
// Format an endpoint
endpoint := "dns://" + net.JoinHostPort(address, strconv.FormatUint(uint64(port), 10))
// Create the actual middleware server
server, err := dnsserver.NewServer(endpoint, []*dnsserver.Config{createConfig(address, port, NewMetricsPlugin(chain))})
if err != nil {
return nil, err
}
return &Listener{server: server, log: log}, nil
}