Merge pull request #259 from 9seconds/go118

Support of Go 1.18

.github/workflows/ci.yaml

@@ -42,7 +42,7 @@ jobs:
     strategy:
       matrix:
         go_version:
-          - ^1.17
+          - ^1.18
     steps:
       - name: Checkout
         uses: actions/checkout@v2
@@ -69,6 +69,38 @@ jobs:
         with:
           file: ./coverage.txt
 
+  fuzz:
+    name: Fuzzing
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          submodules: recursive
+
+      - name: Setup Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ^1.18
+
+      - name: Cache fuzz results
+        uses: actions/cache@v2
+        with:
+          path: ~/.cache/go-build/fuzz
+          key: ${{ runner.os }}-go-${{ hashFiles('**/*_fuzz_test.go', '**/*_fuzz_internal_test.go') }}
+          restore-keys: ${{ runner.os }}-go-
+
+      - name: Cache dependencies
+        uses: actions/cache@v2
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: ${{ runner.os }}-go-
+
+      - name: Run fuzzing
+        run: make -j4 fuzz
+
   lint:
     name: Lint
     runs-on: ubuntu-latest
@@ -79,10 +111,15 @@ jobs:
         with:
           submodules: recursive
 
-      - name: Run linter
-        uses: golangci/golangci-lint-action@v2
+      - name: Setup Go
+        uses: actions/setup-go@v2
         with:
-          version: v1.44.2
+          go-version: ^1.18
+
+      - name: Run linter
+        uses: golangci/golangci-lint-action@v3
+        with:
+          version: v1.45.0
 
   docker:
     name: Docker

.golangci.toml

@@ -9,4 +9,4 @@ format = "colored-line-number"
 
 [linters]
 enable-all = true
-disable = ["ireturn", "varnamelen", "gochecknoglobals", "gas", "goerr113", "exhaustivestruct", "containedctx"]
+disable = ["thelper", "ireturn", "varnamelen", "gochecknoglobals", "gas", "goerr113", "exhaustivestruct", "containedctx"]

Dockerfile

@@ -1,7 +1,7 @@
 ###############################################################################
 # BUILD STAGE
 
-FROM golang:1.17-alpine AS build
+FROM golang:1.18-alpine AS build
 
 RUN set -x \
   && apk --no-cache --update add \

Makefile

@@ -2,12 +2,12 @@ ROOT_DIR     := $(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
 IMAGE_NAME   := mtg
 APP_NAME     := $(IMAGE_NAME)
 
-GOLANGCI_LINT_VERSION := v1.44.2
+GOLANGCI_LINT_VERSION := v1.45.0
 
-VERSION_GO         := $(shell go version)
-VERSION_DATE       := $(shell date -Ru)
-VERSION_TAG        := $(shell git describe --tags --always)
-COMMON_BUILD_FLAGS := -trimpath -mod=readonly -ldflags="-extldflags '-static' -s -w -X 'main.version=$(VERSION_TAG) ($(VERSION_GO)) [$(VERSION_DATE)]'"
+VERSION            := $(shell git describe --exact-match HEAD 2>/dev/null || git describe --tags --always)
+COMMON_BUILD_FLAGS := -trimpath -mod=readonly -ldflags="-extldflags '-static' -s -w -X 'main.version=$(VERSION)'"
+
+FUZZ_FLAGS := -fuzztime=120s
 
 GOBIN  := $(ROOT_DIR)/.bin
 GOTOOL := env "GOBIN=$(GOBIN)" "PATH=$(ROOT_DIR)/.bin:$(PATH)"
@@ -78,7 +78,7 @@ install-tools: install-tools-lint install-tools-godoc install-tools-gofumpt inst
 
 .PHONY: install-tools-lint
 install-tools-lint: .bin
-	@curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh \
+	@curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh \
 		| bash -s -- -b "$(GOBIN)" "$(GOLANGCI_LINT_VERSION)"
 
 .PHONY: install-tools-godoc
@@ -95,4 +95,27 @@ install-tools-goreleaser: .bin
 
 .PHONY: update-deps
 update-deps:
-	@go get -u && go mod tidy -go=1.17
+	@go get -u && go mod tidy -go=1.18
+
+.PHONY: fuzz
+fuzz: fuzz-ClientHello fuzz-ServerGenerateHandshakeFrame fuzz-ClientHandshake fuzz-ServerReceive fuzz-ServerSend
+
+.PHONY: fuzz-ClientHello
+fuzz-ClientHello:
+	@go test -fuzz=FuzzClientHello $(FUZZ_FLAGS) "$(ROOT_DIR)/mtglib/internal/faketls"
+
+.PHONY: fuzz-ServerGenerateHandshakeFrame
+fuzz-ServerGenerateHandshakeFrame:
+	@go test -fuzz=FuzzServerGenerateHandshakeFrame $(FUZZ_FLAGS) "$(ROOT_DIR)/mtglib/internal/obfuscated2"
+
+.PHONY: fuzz-ClientHandshake
+fuzz-ClientHandshake:
+	@go test -fuzz=FuzzClientHandshake $(FUZZ_FLAGS) "$(ROOT_DIR)/mtglib/internal/obfuscated2"
+
+.PHONY: fuzz-ServerReceive
+fuzz-ServerReceive:
+	@go test -fuzz=FuzzServerReceive $(FUZZ_FLAGS) "$(ROOT_DIR)/mtglib/internal/obfuscated2"
+
+.PHONY: fuzz-ServerSend
+fuzz-ServerSend:
+	@go test -fuzz=FuzzServerSend $(FUZZ_FLAGS) "$(ROOT_DIR)/mtglib/internal/obfuscated2"

go.mod

@@ -1,6 +1,6 @@
 module github.com/9seconds/mtg/v2
 
-go 1.17
+go 1.18
 
 require (
 	github.com/OneOfOne/xxhash v1.2.8

go.sum

@@ -416,7 +416,6 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210603081109-ebe580a85c40/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220114195835-da31bd327af9/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5 h1:y/woIyUBFbpQGKS0u1aHF/40WUDnek3fPOyD08H5Vng=

internal/cli/run_proxy.go

@@ -89,7 +89,8 @@ func makeAntiReplayCache(conf *config.Config) mtglib.AntiReplayCache {
 func makeIPBlocklist(conf config.ListConfig,
 	logger mtglib.Logger,
 	ntw mtglib.Network,
-	updateCallback ipblocklist.FireholUpdateCallback) (mtglib.IPBlocklist, error) {
+	updateCallback ipblocklist.FireholUpdateCallback,
+) (mtglib.IPBlocklist, error) {
 	if !conf.Enabled.Get(false) {
 		return ipblocklist.NewNoop(), nil
 	}

internal/testlib/mtglib_network_mock.go

@@ -25,6 +25,7 @@ func (m *MtglibNetworkMock) DialContext(ctx context.Context, network, address st
 }
 
 func (m *MtglibNetworkMock) MakeHTTPClient(dialFunc func(ctx context.Context,
-	network, address string) (essentials.Conn, error)) *http.Client {
+	network, address string) (essentials.Conn, error),
+) *http.Client {
 	return m.Called(dialFunc).Get(0).(*http.Client) // nolint: forcetypeassert
 }

ipblocklist/firehol.go

@@ -155,7 +155,8 @@ func (f *Firehol) update() {
 
 func (f *Firehol) updateFromFile(mutex sync.Locker,
 	ranger cidranger.Ranger,
-	scanner *bufio.Scanner) error {
+	scanner *bufio.Scanner,
+) error {
 	for scanner.Scan() {
 		text := scanner.Text()
 		text = fireholRegexpComment.ReplaceAllLiteralString(text, "")
@@ -216,7 +217,8 @@ func NewFirehol(logger mtglib.Logger, network mtglib.Network,
 	downloadConcurrency uint,
 	urls []string,
 	localFiles []string,
-	updateCallback FireholUpdateCallback) (*Firehol, error) {
+	updateCallback FireholUpdateCallback,
+) (*Firehol, error) {
 	blocklists := []files.File{}
 
 	for _, v := range localFiles {
@@ -245,7 +247,8 @@ func NewFirehol(logger mtglib.Logger, network mtglib.Network,
 func NewFireholFromFiles(logger mtglib.Logger,
 	downloadConcurrency uint,
 	blocklists []files.File,
-	updateCallback FireholUpdateCallback) (*Firehol, error) {
+	updateCallback FireholUpdateCallback,
+) (*Firehol, error) {
 	if downloadConcurrency == 0 {
 		downloadConcurrency = DefaultFireholDownloadConcurrency
 	}

main.go

@@ -9,7 +9,10 @@
 package main
 
 import (
+	"fmt"
 	"math/rand"
+	"runtime/debug"
+	"strconv"
 	"time"
 
 	"github.com/9seconds/mtg/v2/internal/cli"
@@ -26,6 +29,32 @@ func main() {
 		panic(err)
 	}
 
+	if buildInfo, ok := debug.ReadBuildInfo(); ok {
+		vcsCommit := "<no-commit>"
+		vcsDate := time.Now()
+		vcsDirty := ""
+
+		for _, setting := range buildInfo.Settings {
+			switch setting.Key {
+			case "vcs.time":
+				vcsDate, _ = time.Parse(time.RFC3339, setting.Value)
+			case "vcs.revision":
+				vcsCommit = setting.Value
+			case "vcs.modified":
+				if isDirty, _ := strconv.ParseBool(setting.Value); isDirty {
+					vcsDirty = " [dirty]"
+				}
+			}
+		}
+
+		version = fmt.Sprintf("%s (%s: %s on %s%s)",
+			version,
+			buildInfo.GoVersion,
+			vcsDate.Format(time.RFC3339),
+			vcsCommit,
+			vcsDirty)
+	}
+
 	cli := &cli.CLI{}
 	ctx := kong.Parse(cli, kong.Vars{
 		"version": version,

mtglib/internal/faketls/client_hello_fuzz_test.go

@@ -0,0 +1,21 @@
+package faketls_test
+
+import (
+	"testing"
+
+	"github.com/9seconds/mtg/v2/mtglib/internal/faketls"
+	"github.com/stretchr/testify/require"
+)
+
+var FuzzClientHelloSecret = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
+
+func FuzzClientHello(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+
+	f.Fuzz(func(t *testing.T, frame []byte) {
+		_, err := faketls.ParseClientHello(FuzzClientHelloSecret, frame)
+
+		// a probability of having != err is almost negligible
+		require.Error(t, err)
+	})
+}

mtglib/internal/faketls/init.go

@@ -19,7 +19,7 @@ const (
 
 	// ClientHelloMinLen is a minimal possible length of
 	// ClientHello record.
-	ClientHelloMinLen = 4
+	ClientHelloMinLen = 6
 
 	// WelcomePacketRandomOffset is an offset of random in ServerHello
 	// packet (including record envelope).

mtglib/internal/obfuscated2/client_handshake_fuzz_internal_test.go

@@ -0,0 +1,32 @@
+package obfuscated2
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+var FuzzClientHandshakeSecret = []byte{1, 2, 3}
+
+func FuzzClientHandshake(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+
+	f.Fuzz(func(t *testing.T, frame []byte) {
+		data := bytes.NewReader(frame)
+
+		if _, _, _, err := ClientHandshake(FuzzClientHandshakeSecret, data); err != nil {
+			return
+		}
+
+		handshake := clientHandhakeFrame{}
+		require.Len(t, frame, handshakeFrameLen)
+
+		copy(handshake.data[:], frame)
+
+		decryptor := handshake.decryptor(FuzzClientHandshakeSecret)
+		decryptor.XORKeyStream(handshake.data[:], handshake.data[:])
+
+		require.Equal(t, handshakeConnectionType, handshake.connectionType())
+	})
+}

mtglib/internal/obfuscated2/init_test.go

@@ -1,12 +1,20 @@
 package obfuscated2_test
 
 import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"os"
 	"path/filepath"
 	"strings"
+	"testing"
+
+	"github.com/9seconds/mtg/v2/internal/testlib"
+	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
+	"github.com/stretchr/testify/require"
 )
 
 type snapshotBytes struct {
@@ -50,6 +58,14 @@ type SnapshotTestSuite struct {
 	snapshots map[string]*Obfuscated2Snapshot
 }
 
+type ServerHandshakeTestData struct {
+	connMock *testlib.EssentialsConnMock
+
+	proxyConn obfuscated2.Conn
+	encryptor cipher.Stream
+	decryptor cipher.Stream
+}
+
 func (suite *SnapshotTestSuite) IngestSnapshots(dirname, namePrefix string) error {
 	suite.snapshots = map[string]*Obfuscated2Snapshot{}
 
@@ -81,3 +97,41 @@ func (suite *SnapshotTestSuite) IngestSnapshots(dirname, namePrefix string) erro
 
 	return nil
 }
+
+func NewServerHandshakeTestData(t *testing.T) ServerHandshakeTestData {
+	buf := &bytes.Buffer{}
+	connMock := &testlib.EssentialsConnMock{}
+
+	handshakeEnc, handshakeDec, err := obfuscated2.ServerHandshake(buf)
+	require.NoError(t, err)
+
+	serverEncrypted := buf.Bytes()
+	decBlock, _ := aes.NewCipher(serverEncrypted[8 : 8+32])
+	decryptor := cipher.NewCTR(decBlock, serverEncrypted[8+32:8+32+16])
+
+	serverDecrypted := make([]byte, len(serverEncrypted))
+	decryptor.XORKeyStream(serverDecrypted, serverEncrypted)
+
+	require.Equal(t, "3d3d3Q",
+		base64.RawStdEncoding.EncodeToString(serverDecrypted[8+32+16:8+32+16+4]))
+
+	serverEncryptedReverted := make([]byte, len(serverEncrypted))
+
+	for i := 0; i < 32+16; i++ {
+		serverEncryptedReverted[8+i] = serverEncrypted[8+32+16-1-i]
+	}
+
+	encBlock, _ := aes.NewCipher(serverEncryptedReverted[8 : 8+32])
+	encryptor := cipher.NewCTR(encBlock, serverEncryptedReverted[8+32:8+32+16])
+
+	return ServerHandshakeTestData{
+		connMock: connMock,
+		proxyConn: obfuscated2.Conn{
+			Conn:      connMock,
+			Encryptor: handshakeEnc,
+			Decryptor: handshakeDec,
+		},
+		encryptor: encryptor,
+		decryptor: decryptor,
+	}
+}

mtglib/internal/obfuscated2/server_handshake_fuzz_internal_test.go

@@ -0,0 +1,30 @@
+package obfuscated2
+
+import (
+	"encoding/binary"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func FuzzServerGenerateHandshakeFrame(f *testing.F) {
+	f.Fuzz(func(t *testing.T, arg int) {
+		frame := generateServerHanshakeFrame()
+
+		assert.NotEqualValues(t, 0xef, frame.data[0])
+
+		firstBytes := binary.LittleEndian.Uint32(frame.data[:4])
+		assert.NotEqualValues(t, 0x44414548, firstBytes)
+		assert.NotEqualValues(t, 0x54534f50, firstBytes)
+		assert.NotEqualValues(t, 0x20544547, firstBytes)
+		assert.NotEqualValues(t, 0x4954504f, firstBytes)
+		assert.NotEqualValues(t, 0xeeeeeeee, firstBytes)
+
+		assert.NotEqualValues(
+			t,
+			0,
+			frame.data[4]|frame.data[5]|frame.data[6]|frame.data[7])
+
+		assert.Equal(t, handshakeConnectionType, frame.connectionType())
+	})
+}

mtglib/internal/obfuscated2/server_handshake_fuzz_test.go

@@ -0,0 +1,58 @@
+package obfuscated2_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+)
+
+func FuzzServerSend(f *testing.F) {
+	f.Add([]byte{1, 2, 3, 4, 5})
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		handshakeData := NewServerHandshakeTestData(t)
+
+		handshakeData.connMock.
+			On("Write", mock.Anything).
+			Return(len(data), nil).
+			Once().
+			Run(func(args mock.Arguments) {
+				message := make([]byte, len(data))
+				handshakeData.decryptor.XORKeyStream(message, args.Get(0).([]byte)) // nolint: forcetypeassert
+				assert.Equal(t, message, data)
+			})
+
+		n, err := handshakeData.proxyConn.Write(data)
+
+		assert.EqualValues(t, len(data), n)
+		assert.NoError(t, err)
+		handshakeData.connMock.AssertExpectations(t)
+	})
+}
+
+func FuzzServerReceive(f *testing.F) {
+	f.Add([]byte{1, 2, 3, 4, 5})
+
+	f.Fuzz(func(t *testing.T, data []byte) {
+		handshakeData := NewServerHandshakeTestData(t)
+		buffer := make([]byte, len(data))
+
+		handshakeData.connMock.
+			On("Read", mock.Anything).
+			Return(len(data), nil).
+			Once().
+			Run(func(args mock.Arguments) {
+				message := make([]byte, len(data))
+				handshakeData.encryptor.XORKeyStream(message, data)
+				copy(args.Get(0).([]byte), message) // nolint: forcetypeassert
+			})
+
+		n, err := handshakeData.proxyConn.Read(buffer)
+
+		assert.EqualValues(t, len(data), n)
+		assert.NoError(t, err)
+		assert.Equal(t, data, buffer)
+		handshakeData.connMock.AssertExpectations(t)
+	})
+}

mtglib/internal/obfuscated2/server_handshake_test.go

@@ -1,14 +1,8 @@
 package obfuscated2_test
 
 import (
-	"bytes"
-	"crypto/aes"
-	"crypto/cipher"
-	"encoding/base64"
 	"testing"
 
-	"github.com/9seconds/mtg/v2/internal/testlib"
-	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/suite"
 )
@@ -16,64 +10,31 @@ import (
 type ServerHandshakeTestSuite struct {
 	suite.Suite
 
-	connMock  *testlib.EssentialsConnMock
-	proxyConn obfuscated2.Conn
-	encryptor cipher.Stream
-	decryptor cipher.Stream
+	data ServerHandshakeTestData
 }
 
 func (suite *ServerHandshakeTestSuite) SetupTest() {
-	buf := &bytes.Buffer{}
-	suite.connMock = &testlib.EssentialsConnMock{}
-
-	encryptor, decryptor, err := obfuscated2.ServerHandshake(buf)
-	suite.NoError(err)
-
-	suite.proxyConn = obfuscated2.Conn{
-		Conn:      suite.connMock,
-		Encryptor: encryptor,
-		Decryptor: decryptor,
-	}
-
-	serverEncrypted := buf.Bytes()
-
-	decBlock, _ := aes.NewCipher(serverEncrypted[8 : 8+32])
-	suite.decryptor = cipher.NewCTR(decBlock, serverEncrypted[8+32:8+32+16])
-
-	serverDecrypted := make([]byte, len(serverEncrypted))
-	suite.decryptor.XORKeyStream(serverDecrypted, serverEncrypted)
-
-	suite.Equal("3d3d3Q",
-		base64.RawStdEncoding.EncodeToString(serverDecrypted[8+32+16:8+32+16+4]))
-
-	serverEncryptedReverted := make([]byte, len(serverEncrypted))
-
-	for i := 0; i < 32+16; i++ {
-		serverEncryptedReverted[8+i] = serverEncrypted[8+32+16-1-i]
-	}
-
-	encBlock, _ := aes.NewCipher(serverEncryptedReverted[8 : 8+32])
-	suite.encryptor = cipher.NewCTR(encBlock, serverEncryptedReverted[8+32:8+32+16])
+	suite.data = NewServerHandshakeTestData(suite.T())
 }
 
 func (suite *ServerHandshakeTestSuite) TearDownTest() {
-	suite.connMock.AssertExpectations(suite.T())
+	suite.data.connMock.AssertExpectations(suite.T())
 }
 
 func (suite *ServerHandshakeTestSuite) TestSendToTelegram() {
 	messageToTelegram := []byte{10, 11, 12, 13, 14, 'a'}
 
-	suite.connMock.
+	suite.data.connMock.
 		On("Write", mock.Anything).
 		Return(len(messageToTelegram), nil).
 		Once().
 		Run(func(args mock.Arguments) {
 			message := make([]byte, len(messageToTelegram))
-			suite.decryptor.XORKeyStream(message, args.Get(0).([]byte)) // nolint: forcetypeassert
+			suite.data.decryptor.XORKeyStream(message, args.Get(0).([]byte)) // nolint: forcetypeassert
 			suite.Equal(messageToTelegram, message)
 		})
 
-	n, err := suite.proxyConn.Write(messageToTelegram)
+	n, err := suite.data.proxyConn.Write(messageToTelegram)
 	suite.EqualValues(len(messageToTelegram), n)
 	suite.NoError(err)
 }
@@ -82,17 +43,17 @@ func (suite *ServerHandshakeTestSuite) TestRecieveFromTelegram() {
 	messageFromTelegram := []byte{10, 11, 12, 13, 14, 'a'}
 	buffer := make([]byte, len(messageFromTelegram))
 
-	suite.connMock.
+	suite.data.connMock.
 		On("Read", mock.Anything).
 		Return(len(messageFromTelegram), nil).
 		Once().
 		Run(func(args mock.Arguments) {
 			message := make([]byte, len(messageFromTelegram))
-			suite.encryptor.XORKeyStream(message, messageFromTelegram)
+			suite.data.encryptor.XORKeyStream(message, messageFromTelegram)
 			copy(args.Get(0).([]byte), message) // nolint: forcetypeassert
 		})
 
-	n, err := suite.proxyConn.Read(buffer)
+	n, err := suite.data.proxyConn.Read(buffer)
 	suite.EqualValues(len(messageFromTelegram), n)
 	suite.NoError(err)
 	suite.Equal(messageFromTelegram, buffer)

network/circuit_breaker.go

@@ -36,7 +36,8 @@ func (c *circuitBreakerDialer) Dial(network, address string) (essentials.Conn, e
 }
 
 func (c *circuitBreakerDialer) DialContext(ctx context.Context,
-	network, address string) (essentials.Conn, error) {
+	network, address string,
+) (essentials.Conn, error) {
 	switch atomic.LoadUint32(&c.state) {
 	case circuitBreakerStateClosed:
 		return c.doClosed(ctx, network, address)
@@ -48,7 +49,8 @@ func (c *circuitBreakerDialer) DialContext(ctx context.Context,
 }
 
 func (c *circuitBreakerDialer) doClosed(ctx context.Context,
-	network, address string) (essentials.Conn, error) {
+	network, address string,
+) (essentials.Conn, error) {
 	conn, err := c.Dialer.DialContext(ctx, network, address)
 
 	select {
@@ -80,7 +82,8 @@ func (c *circuitBreakerDialer) doClosed(ctx context.Context,
 }
 
 func (c *circuitBreakerDialer) doHalfOpened(ctx context.Context,
-	network, address string) (essentials.Conn, error) {
+	network, address string,
+) (essentials.Conn, error) {
 	if !atomic.CompareAndSwapUint32(&c.halfOpenAttempts, 0, 1) {
 		return nil, ErrCircuitBreakerOpened
 	}
@@ -174,14 +177,16 @@ func (c *circuitBreakerDialer) stopTimer(timerRef **time.Timer) {
 }
 
 func (c *circuitBreakerDialer) ensureTimer(timerRef **time.Timer,
-	timeout time.Duration, callback func()) {
+	timeout time.Duration, callback func(),
+) {
 	if *timerRef == nil {
 		*timerRef = time.AfterFunc(timeout, callback)
 	}
 }
 
 func newCircuitBreakerDialer(baseDialer Dialer,
-	openThreshold uint32, halfOpenTimeout, resetFailuresTimeout time.Duration) Dialer {
+	openThreshold uint32, halfOpenTimeout, resetFailuresTimeout time.Duration,
+) Dialer {
 	cb := &circuitBreakerDialer{
 		Dialer:               baseDialer,
 		stateMutexChan:       make(chan bool, 1),

network/network.go

@@ -61,7 +61,8 @@ func (n *network) DialContext(ctx context.Context, protocol, address string) (es
 }
 
 func (n *network) MakeHTTPClient(dialFunc func(ctx context.Context,
-	network, address string) (essentials.Conn, error)) *http.Client {
+	network, address string) (essentials.Conn, error),
+) *http.Client {
 	if dialFunc == nil {
 		dialFunc = n.DialContext
 	}
@@ -123,7 +124,8 @@ func (n *network) dnsResolve(protocol, address string) ([]string, error) {
 // It brings simple DNS cache and DNS-Over-HTTPS when necessary.
 func NewNetwork(dialer Dialer,
 	userAgent, dohHostname string,
-	httpTimeout time.Duration) (mtglib.Network, error) {
+	httpTimeout time.Duration,
+) (mtglib.Network, error) {
 	switch {
 	case httpTimeout < 0:
 		return nil, fmt.Errorf("timeout should be positive number %s", httpTimeout)
@@ -146,7 +148,8 @@ func NewNetwork(dialer Dialer,
 
 func makeHTTPClient(userAgent string,
 	timeout time.Duration,
-	dialFunc func(ctx context.Context, network, address string) (essentials.Conn, error)) *http.Client {
+	dialFunc func(ctx context.Context, network, address string) (essentials.Conn, error),
+) *http.Client {
 	return &http.Client{
 		Timeout: timeout,
 		Transport: networkHTTPTransport{

stats/statsd.go

@@ -171,7 +171,8 @@ func (s StatsdFactory) Make() events.Observer {
 //
 // Valid tagFormats are 'datadog', 'influxdb' and 'graphite'.
 func NewStatsd(address string, log logger.StdLikeLogger,
-	metricPrefix, tagFormat string) (StatsdFactory, error) {
+	metricPrefix, tagFormat string,
+) (StatsdFactory, error) {
 	options := []statsd.Option{
 		statsd.MetricPrefix(metricPrefix),
 		statsd.Logger(log),