Merge pull request #136 from 9seconds/prefer-options

Option for IP preference

Makefile

 
 CC_BINARIES  := $(shell bash -c "echo -n $(APP_NAME)-{linux,freebsd,openbsd}-{386,amd64} $(APP_NAME)-linux-{arm,arm64}")
 
-GOLANGCI_LINT_VERSION := v1.23.3
+GOLANGCI_LINT_VERSION := v1.24.0
 
 VERSION_GO         := $(shell go version)
 VERSION_DATE       := $(shell date -Ru)

config/config.go

 	SecretModeTLS
 )
 
+type PreferIP uint8
+
+const (
+	PreferIPv4 PreferIP = iota
+	PreferIPv6
+)
+
 const SimpleSecretLength = 16
 
 type OptionType uint8
 	OptionTypeDebug OptionType = iota
 	OptionTypeVerbose
 
+	OptionTypePreferIP
+
 	OptionTypeBind
 	OptionTypePublicIPv4
 	OptionTypePublicIPv6
 	Debug      bool       `json:"debug"`
 	Verbose    bool       `json:"verbose"`
 	SecretMode SecretMode `json:"secret_mode"`
+	PreferIP   PreferIP   `json:"prefer_ip"`
 
 	Secret []byte `json:"secret"`
 	AdTag  []byte `json:"adtag"`
 			C.Debug = opt.Value.(bool)
 		case OptionTypeVerbose:
 			C.Verbose = opt.Value.(bool)
+		case OptionTypePreferIP:
+			value := opt.Value.(string)
+			switch value {
+			case "ipv4":
+				C.PreferIP = PreferIPv4
+			case "ipv6":
+				C.PreferIP = PreferIPv6
+			default:
+				return fmt.Errorf("incorrect direct IP mode %s", value)
+			}
 		case OptionTypeBind:
 			C.Bind = opt.Value.(*net.TCPAddr)
 		case OptionTypePublicIPv4:

go.mod

 require (
 	github.com/VictoriaMetrics/fastcache v1.5.7
 	github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d
-	github.com/beevik/ntp v0.2.0
-	github.com/golang/protobuf v1.3.3 // indirect
-	github.com/prometheus/client_golang v1.4.0
+	github.com/beevik/ntp v0.3.0
+	github.com/golang/protobuf v1.3.5 // indirect
+	github.com/prometheus/client_golang v1.5.1
+	github.com/prometheus/procfs v0.0.11 // indirect
 	github.com/smira/go-statsd v1.3.1
-	go.uber.org/atomic v1.5.1 // indirect
-	go.uber.org/multierr v1.4.0 // indirect
-	go.uber.org/zap v1.13.0
-	golang.org/x/crypto v0.0.0-20200128174031-69ecbb4d6d5d
-	golang.org/x/lint v0.0.0-20200130185559-910be7a94367 // indirect
-	golang.org/x/net v0.0.0-20200202094626-16171245cfb2 // indirect
-	golang.org/x/sys v0.0.0-20200202164722-d101bd2416d5
-	golang.org/x/tools v0.0.0-20200204074204-1cc6d1ef6c74 // indirect
+	go.uber.org/zap v1.14.1
+	golang.org/x/crypto v0.0.0-20200317142112-1b76d66859c6
+	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect
+	golang.org/x/net v0.0.0-20200319234117-63522dbf7eec // indirect
+	golang.org/x/sys v0.0.0-20200317113312-5766fd39f98d
+	golang.org/x/tools v0.0.0-20200319210407-521f4a0cd458 // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
+	honnef.co/go/tools v0.0.1-2020.1.3 // indirect
 )

go.sum

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 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
-golang.org/x/tools v0.0.0-20200204074204-1cc6d1ef6c74 h1:KW20qMcLRWuIgjdCpHFJbVZA7zsDKtFXPNcm7/eI5ZA=
-golang.org/x/tools v0.0.0-20200204074204-1cc6d1ef6c74/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
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+golang.org/x/tools v0.0.0-20200319210407-521f4a0cd458/go.mod h1:Sl4aGygMT6LrqrWclx+PTx3U+LnKx/seiNR+3G19Ar8=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 gopkg.in/yaml.v2 v2.2.5/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 honnef.co/go/tools v0.0.1-2019.2.3 h1:3JgtbtFHMiCmsznwGVTUWbgGov+pVqnlf1dEJTNAXeM=
 honnef.co/go/tools v0.0.1-2019.2.3/go.mod h1:a3bituU0lyd329TUQxRnasdCoJDkEUEAqEt0JzvZhAg=
+honnef.co/go/tools v0.0.1-2020.1.3 h1:sXmLre5bzIR6ypkjXCDI3jHPssRhc8KD/Ome589sc3U=
+honnef.co/go/tools v0.0.1-2020.1.3/go.mod h1:X/FiERA/W4tHapMX5mGpAtMSVEeEUOyHaw9vFzvIQ3k=

main.go

 		Short('v').
 		Envar("MTG_VERBOSE").
 		Bool()
+	runPreferIP = runCommand.Flag("prefer-ip",
+		"Prefer this IP protocol if possible. Valid options are 'ipv4' and 'ipv6'").
+		Envar("MTG_PREFER_DIRECT_IP").
+		Default("ipv6").
+		Enum("ipv4", "ipv6")
 	runBind = runCommand.Flag("bind",
 		"Host:Port to bind proxy to.").
 		Short('b').
 		err := config.Init(
 			config.Opt{Option: config.OptionTypeDebug, Value: *runDebug},
 			config.Opt{Option: config.OptionTypeVerbose, Value: *runVerbose},
+			config.Opt{Option: config.OptionTypePreferIP, Value: *runPreferIP},
 			config.Opt{Option: config.OptionTypeBind, Value: *runBind},
 			config.Opt{Option: config.OptionTypePublicIPv4, Value: *runPublicIPv4},
 			config.Opt{Option: config.OptionTypePublicIPv6, Value: *runPublicIPv6},

telegram/base.go

 
 	"go.uber.org/zap"
 
+	"github.com/9seconds/mtg/config"
 	"github.com/9seconds/mtg/conntypes"
 	"github.com/9seconds/mtg/utils"
 	"github.com/9seconds/mtg/wrappers/stream"
 
 func (b *baseTelegram) dial(dc conntypes.DC,
 	protocol conntypes.ConnectionProtocol) (conntypes.StreamReadWriteCloser, error) {
-	addresses := make([]string, 0, 2)
-
-	if protocol&conntypes.ConnectionProtocolIPv6 != 0 {
-		addresses = append(addresses, b.chooseAddress(b.v6Addresses, dc, b.v6DefaultDC))
-	}
-
-	if protocol&conntypes.ConnectionProtocolIPv4 != 0 {
-		addresses = append(addresses, b.chooseAddress(b.v4Addresses, dc, b.v4DefaultDC))
-	}
-
-	for _, addr := range addresses {
+	for _, addr := range b.getAddresses(dc, protocol) {
 		conn, err := b.dialer.Dial("tcp", addr)
 		if err != nil {
 			b.logger.Infow("Cannot dial to Telegram", "address", addr, "error", err)
 	return nil, errors.New("cannot dial to the chosen DC")
 }
 
+func (b *baseTelegram) getAddresses(dc conntypes.DC, protocol conntypes.ConnectionProtocol) []string {
+	addresses := make([]string, 0, 2)
+	protos := []conntypes.ConnectionProtocol{
+		conntypes.ConnectionProtocolIPv6,
+		conntypes.ConnectionProtocolIPv4,
+	}
+
+	if config.C.PreferIP == config.PreferIPv4 {
+		protos[0], protos[1] = protos[1], protos[0]
+	}
+
+	for _, proto := range protos {
+		switch {
+		case proto&protocol == 0:
+		case proto&conntypes.ConnectionProtocolIPv6 != 0:
+			addresses = append(addresses, b.chooseAddress(b.v6Addresses, dc, b.v6DefaultDC))
+		case proto&conntypes.ConnectionProtocolIPv4 != 0:
+			addresses = append(addresses, b.chooseAddress(b.v4Addresses, dc, b.v4DefaultDC))
+		}
+	}
+
+	return addresses
+}
+
 func (b *baseTelegram) chooseAddress(addresses map[conntypes.DC][]string,
 	dc, defaultDC conntypes.DC) string {
 	addrs, ok := addresses[dc]