Fix ordering in cleanup function

AGENTS.md

@@ -116,6 +116,7 @@ Mocking works with the `go.uber.org/mock` library, and the `mockgen` tool.
   - **Never** use `.AnyTimes()` on mocks. Always define the number of times a certain mock call should be called, with `.Times(3)` for example.
   - **Always** set the `.Return(...)` on the mock if the function returns something.
   - Avoid using **mock helpers** functions, prefer a bit of repetition than tight coupling and dependency
+  - Always define the gomock controller `ctrl` in the subtest and not in the parent test, or a subtest mock failing will crash all the other subtests.
 
 ### main.go
 

internal/restrictednet/client.go

@@ -4,7 +4,10 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
 	"net/http"
+	"net/netip"
+	"strconv"
 
 	"github.com/qdm12/dns/v2/pkg/provider"
 )
@@ -14,44 +17,53 @@ import (
 // It is not meant to be high performance, although it can be used for
 // multiple requests and concurrently.
 type Client struct {
+	outboundInterface string
 	ipv6Supported     bool
 	firewall          Firewall
-	outboundInterface string
 	dohServers        []provider.DoHServer
-	httpsPort         uint16
 }
 
-func New(firewall Firewall, defaultInterface string, ipv6Supported bool,
-	upstreamResolvers []provider.Provider,
-) (*Client, error) {
-	dohServers := make([]provider.DoHServer, len(upstreamResolvers))
-	for i, upstreamResolver := range upstreamResolvers {
+func New(settings Settings) *Client {
+	if err := settings.validate(); err != nil {
+		panic(fmt.Sprintf("invalid settings: %v", err)) // programming error
+	}
+	dohServers := make([]provider.DoHServer, len(settings.UpstreamResolvers))
+	for i, upstreamResolver := range settings.UpstreamResolvers {
 		dohServers[i] = upstreamResolver.DoH
 	}
 
-	const defaultHTTPSPort = 443
 	return &Client{
-		firewall:          firewall,
-		outboundInterface: defaultInterface,
-		ipv6Supported:     ipv6Supported,
+		outboundInterface: settings.DefaultInterface,
+		ipv6Supported:     *settings.IPv6Supported,
+		firewall:          settings.Firewall,
 		dohServers:        dohServers,
-		httpsPort:         defaultHTTPSPort,
-	}, nil
+	}
 }
 
-func (c *Client) OpenHTTPSByDomain(ctx context.Context, domain string) (
+func (c *Client) OpenHTTPSByDomain(ctx context.Context, hostname string) (
 	httpClient *http.Client, cleanup func() error, err error,
 ) {
-	resolvedIPs, err := c.ResolveName(ctx, domain)
+	host, portStr, err := net.SplitHostPort(hostname)
+	if err != nil {
+		return nil, nil, fmt.Errorf("splitting host and port: %w", err)
+	}
+	resolvedIPs, err := c.ResolveName(ctx, host)
 	if err != nil {
 		return nil, nil, fmt.Errorf("resolving name: %w", err)
 	} else if len(resolvedIPs) == 0 {
-		return nil, nil, fmt.Errorf("no IP address found for name %q", domain)
+		return nil, nil, fmt.Errorf("no IP address found for name %q", host)
 	}
 
+	portUint, err := strconv.ParseUint(portStr, 10, 16)
+	if err != nil {
+		return nil, nil, fmt.Errorf("parsing port: %w", err)
+	}
+	port := uint16(portUint)
+
 	errs := make([]error, 0, len(resolvedIPs))
 	for _, ip := range resolvedIPs {
-		httpClient, cleanup, err := c.OpenHTTPS(ctx, domain, ip)
+		addrPort := netip.AddrPortFrom(ip, port)
+		httpClient, cleanup, err := c.OpenHTTPS(ctx, host, addrPort)
 		if err != nil {
 			errs = append(errs, fmt.Errorf("for %s: %w", ip, err))
 			continue
@@ -59,5 +71,5 @@ func (c *Client) OpenHTTPSByDomain(ctx context.Context, domain string) (
 		return httpClient, cleanup, nil
 	}
 
-	return nil, nil, fmt.Errorf("opening HTTPS to %s: %w", domain, errors.Join(errs...))
+	return nil, nil, fmt.Errorf("opening HTTPS to %s: %w", hostname, errors.Join(errs...))
 }

internal/restrictednet/helpers_test.go

@@ -0,0 +1,5 @@
+package restrictednet
+
+func ptrTo[T any](value T) *T {
+	return &value
+}

internal/restrictednet/https.go

@@ -17,15 +17,13 @@ import (
 
 // OpenHTTPS opens temporary restrictive firewall output for one HTTPS destination.
 // The returned cleanup function must be called to remove the temporary firewall rule and close connections.
-func (c *Client) OpenHTTPS(ctx context.Context, destinationTLSName string, destinationIP netip.Addr,
+func (c *Client) OpenHTTPS(ctx context.Context, destinationTLSName string, destinationAddrPort netip.AddrPort,
 ) (httpClient *http.Client, cleanup func() error, err error) {
-	fd, sourceAddrPort, err := bindSourceConnection(destinationIP)
+	fd, sourceAddrPort, err := bindSourceConnection(destinationAddrPort.Addr())
 	if err != nil {
 		return nil, nil, fmt.Errorf("binding source port: %w", err)
 	}
 
-	destinationAddrPort := netip.AddrPortFrom(destinationIP, c.httpsPort)
-
 	const remove = false
 	err = c.firewall.AcceptOutputFromIPPortToIPPort(ctx, "tcp", c.outboundInterface,
 		sourceAddrPort, destinationAddrPort, remove)
@@ -37,25 +35,26 @@ func (c *Client) OpenHTTPS(ctx context.Context, destinationTLSName string, desti
 	connection, err := connectSourceConnection(ctx, fd, destinationAddrPort)
 	if err != nil {
 		const remove = true
-		_ = c.firewall.AcceptOutputFromIPPortToIPPort(ctx, "tcp", c.outboundInterface,
+		_ = c.firewall.AcceptOutputFromIPPortToIPPort(context.Background(), "tcp", c.outboundInterface,
 			sourceAddrPort, destinationAddrPort, remove)
 		return nil, nil, fmt.Errorf("connecting source socket: %w", err)
 	}
 
-	httpClient = newHTTPSClient(destinationTLSName, connection)
+	dial := makeDial(connection, destinationTLSName)
+	httpClient = newHTTPSClient(destinationTLSName, dial)
 	cleanup = func() error {
 		var errs []error
 		httpClient.CloseIdleConnections()
+		err = connection.Close()
+		if err != nil && !errors.Is(err, net.ErrClosed) {
+			errs = append(errs, fmt.Errorf("closing connection: %w", err))
+		}
 		const remove = true
 		err := c.firewall.AcceptOutputFromIPPortToIPPort(context.Background(), "tcp", c.outboundInterface,
 			sourceAddrPort, destinationAddrPort, remove)
 		if err != nil {
 			errs = append(errs, fmt.Errorf("removing output traffic rule: %w", err))
 		}
-		err = connection.Close()
-		if err != nil {
-			errs = append(errs, fmt.Errorf("closing connection: %w", err))
-		}
 		if len(errs) > 0 {
 			return errors.Join(errs...)
 		}
@@ -64,21 +63,31 @@ func (c *Client) OpenHTTPS(ctx context.Context, destinationTLSName string, desti
 	return httpClient, cleanup, nil
 }
 
-func newHTTPSClient(destinationTLSName string, connection net.Conn) *http.Client {
-	httpTransport := http.DefaultTransport.(*http.Transport).Clone() //nolint:forcetypeassert
-	httpTransport.Proxy = nil
-	httpTransport.MaxIdleConns = 1
-	httpTransport.MaxIdleConnsPerHost = 1
-	httpTransport.MaxConnsPerHost = 1
-	httpTransport.IdleConnTimeout = time.Second
-	httpTransport.TLSClientConfig = &tls.Config{
-		MinVersion: tls.VersionTLS12,
-		ServerName: destinationTLSName,
-	}
+type dialFunc func(ctx context.Context, network, address string) (net.Conn, error)
 
+func newHTTPSClient(destinationTLSName string, dial dialFunc) *http.Client {
+	const timeout = 5 * time.Second
+	transport := &http.Transport{
+		MaxIdleConns:        1,
+		MaxIdleConnsPerHost: 1,
+		MaxConnsPerHost:     1,
+		IdleConnTimeout:     time.Second,
+		TLSClientConfig: &tls.Config{
+			MinVersion: tls.VersionTLS12,
+			ServerName: destinationTLSName,
+		},
+		DialContext: dial,
+	}
+	return &http.Client{
+		Timeout:   timeout,
+		Transport: transport,
+	}
+}
+
+func makeDial(connection net.Conn, tlsName string) dialFunc {
 	_, destinationPort, _ := net.SplitHostPort(connection.RemoteAddr().String())
-	expectedAddress := net.JoinHostPort(destinationTLSName, destinationPort)
-	httpTransport.DialContext = func(_ context.Context, network, address string) (net.Conn, error) {
+	expectedAddress := net.JoinHostPort(tlsName, destinationPort)
+	return func(_ context.Context, network, address string) (net.Conn, error) {
 		switch network {
 		case "tcp", "tcp4", "tcp6":
 		default:
@@ -89,12 +98,6 @@ func newHTTPSClient(destinationTLSName string, connection net.Conn) *http.Client
 		}
 		return connection, nil
 	}
-
-	const timeout = 5 * time.Second
-	return &http.Client{
-		Timeout:   timeout,
-		Transport: httpTransport,
-	}
 }
 
 func bindSourceConnection(destinationIP netip.Addr) (fd int, sourceAddr netip.AddrPort, err error) {

internal/restrictednet/https_test.go

@@ -2,12 +2,14 @@ package restrictednet
 
 import (
 	"context"
-	"net"
+	"fmt"
+	"net/http"
 	"net/netip"
 	"testing"
 
 	"github.com/golang/mock/gomock"
 	"github.com/qdm12/dns/v2/pkg/provider"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -33,31 +35,40 @@ func (m listenAddrPortMatcher) String() string {
 	return "is a valid netip.AddrPort with a valid IP and non-zero port"
 }
 
+type destinationAddrPortMatcher struct {
+	expected netip.AddrPort
+}
+
+func (m destinationAddrPortMatcher) Matches(x any) bool {
+	ip, ok := x.(netip.AddrPort)
+	if !ok {
+		return false
+	}
+	if m.expected.IsValid() {
+		return ip == m.expected
+	}
+	return ip.IsValid() && ip.Port() == m.expected.Port()
+}
+
+func (m destinationAddrPortMatcher) String() string {
+	if m.expected.IsValid() {
+		return "is the same as " + m.expected.String()
+	}
+	return "matches the port " + fmt.Sprint(m.expected.Port())
+}
+
 func Test_Client_OpenHTTPS(t *testing.T) {
 	t.Parallel()
 	ctx := t.Context()
-
-	netConfig := net.ListenConfig{}
-	listener, err := netConfig.Listen(ctx, "tcp", "127.0.0.1:0")
-	require.NoError(t, err)
-	t.Cleanup(func() {
-		_ = listener.Close()
-	})
-	listeningPort := uint16(listener.Addr().(*net.TCPAddr).Port) //nolint:gosec,forcetypeassert
-	go func() {
-		connection, acceptErr := listener.Accept()
-		if acceptErr == nil {
-			_ = connection.Close()
-		}
-	}()
-
 	ctrl := gomock.NewController(t)
-	firewall := NewMockFirewall(ctrl)
 
-	destination := netip.AddrPortFrom(netip.MustParseAddr("127.0.0.1"), listeningPort)
+	const destinationTLSName = "one.one.one.one"
+	destinationAddrPort := netip.AddrPortFrom(netip.AddrFrom4([4]byte{1, 1, 1, 1}), 443)
+
+	firewall := NewMockFirewall(ctrl)
 	sourceMatcher := listenAddrPortMatcher{}
 	firewall.EXPECT().AcceptOutputFromIPPortToIPPort(
-		ctx, "tcp", "eth0", sourceMatcher, destination, false,
+		ctx, "tcp", "eth0", sourceMatcher, destinationAddrPort, false,
 	).DoAndReturn(func(_ context.Context,
 		_, _ string, source, _ netip.AddrPort, _ bool,
 	) error {
@@ -65,20 +76,35 @@ func Test_Client_OpenHTTPS(t *testing.T) {
 		return nil
 	})
 	firewall.EXPECT().AcceptOutputFromIPPortToIPPort(
-		context.Background(), "tcp", "eth0", sourceMatcher, destination, true,
+		context.Background(), "tcp", "eth0", sourceMatcher, destinationAddrPort, true,
 	)
 
 	const ipv6Supported = false
 	upstreamResolvers := []provider.Provider{provider.Google()}
-	client, err := New(firewall, "eth0", ipv6Supported, upstreamResolvers)
-	require.NoError(t, err)
-	client.httpsPort = listeningPort
+	settings := Settings{
+		Firewall:          firewall,
+		DefaultInterface:  "eth0",
+		IPv6Supported:     ptrTo(ipv6Supported),
+		UpstreamResolvers: upstreamResolvers,
+	}
+	client := New(settings)
 
-	httpClient, cleanup, err := client.OpenHTTPS(ctx, "api.example.com", netip.MustParseAddr("127.0.0.1"))
+	httpClient, cleanup, err := client.OpenHTTPS(ctx, destinationTLSName, destinationAddrPort)
 	require.NoError(t, err)
 	require.NotNil(t, httpClient)
 	require.NotNil(t, cleanup)
 
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://"+destinationTLSName, nil)
+	require.NoError(t, err)
+
+	response, err := httpClient.Do(request)
+	t.Cleanup(func() {
+		response.Body.Close()
+	})
+	require.NoError(t, err)
+
+	assert.Equal(t, http.StatusOK, response.StatusCode)
+
 	err = cleanup()
 	require.NoError(t, err)
 }

internal/restrictednet/resolve.go

@@ -76,15 +76,17 @@ func (c *Client) resolveOneQuestionType(ctx context.Context,
 		dohServerIPs = append(dohServerIPs, dohServer.IPv4...)
 
 		for _, dohServerIP := range dohServerIPs {
-			responseMessage, err := c.doHQuery(ctx, queryWire, dohURL, dohServerIP)
+			const defaultDoHPort = 443
+			dohServerAddrPort := netip.AddrPortFrom(dohServerIP, defaultDoHPort)
+			responseMessage, err := c.doHQuery(ctx, queryWire, dohURL, dohServerAddrPort)
 			switch {
 			case err != nil:
-				errs = append(errs, fmt.Errorf("querying DoH server %q at %s: %w",
-					dohServer.URL, dohServerIP, err))
+				errs = append(errs, fmt.Errorf("querying DoH server %q (%s): %w",
+					dohServer.URL, dohServerAddrPort, err))
 				continue
 			case responseMessage.Rcode != dns.RcodeSuccess:
-				errs = append(errs, fmt.Errorf("querying DoH server %q at %s: DNS rcode %s",
-					dohServer.URL, dohServerIP, dns.RcodeToString[responseMessage.Rcode]))
+				errs = append(errs, fmt.Errorf("querying DoH server %q (%s): DNS rcode %s",
+					dohServer.URL, dohServerAddrPort, dns.RcodeToString[responseMessage.Rcode]))
 				continue
 			}
 			addresses := answersToNetipAddrs(responseMessage)
@@ -104,9 +106,9 @@ func (c *Client) resolveOneQuestionType(ctx context.Context,
 }
 
 func (c *Client) doHQuery(ctx context.Context, queryWire []byte,
-	dohURL *url.URL, dohServerIP netip.Addr,
+	dohURL *url.URL, dohServerAddrPort netip.AddrPort,
 ) (responseMessage *dns.Msg, err error) {
-	httpClient, cleanup, err := c.OpenHTTPS(ctx, dohURL.Hostname(), dohServerIP)
+	httpClient, cleanup, err := c.OpenHTTPS(ctx, dohURL.Hostname(), dohServerAddrPort)
 	if err != nil {
 		return nil, fmt.Errorf("opening https connection: %w", err)
 	}

internal/restrictednet/resolve_test.go

@@ -1,80 +1,107 @@
 package restrictednet
 
 import (
+	"context"
 	"net"
 	"net/netip"
 	"testing"
 
+	"github.com/golang/mock/gomock"
 	"github.com/miekg/dns"
+	"github.com/qdm12/dns/v2/pkg/provider"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
+func Test_Client_ResolveName(t *testing.T) {
+	t.Parallel()
+	ctx := t.Context()
+	ctrl := gomock.NewController(t)
+
+	firewall := NewMockFirewall(ctrl)
+	sourceMatcher := listenAddrPortMatcher{}
+	destinationMatcher := destinationAddrPortMatcher{
+		expected: netip.AddrPortFrom(netip.Addr{}, 443),
+	}
+
+	// Add rule
+	firstCall := firewall.EXPECT().AcceptOutputFromIPPortToIPPort(
+		ctx, "tcp", "eth0", sourceMatcher, destinationMatcher, false,
+	).DoAndReturn(func(
+		_ context.Context, _, _ string, source, destination netip.AddrPort, _ bool,
+	) error {
+		sourceMatcher.expected = source
+		destinationMatcher.expected = destination
+		return nil
+	})
+
+	// Removal rule
+	firewall.EXPECT().AcceptOutputFromIPPortToIPPort(
+		context.Background(), "tcp", "eth0", sourceMatcher, destinationMatcher, true,
+	).Return(nil).After(firstCall)
+
+	settings := Settings{
+		DefaultInterface:  "eth0",
+		IPv6Supported:     ptrTo(false),
+		Firewall:          firewall,
+		UpstreamResolvers: []provider.Provider{provider.Cloudflare()},
+	}
+	client := New(settings)
+
+	addresses, err := client.ResolveName(ctx, "github.com")
+	require.NoError(t, err)
+	assert.NotEmpty(t, addresses)
+}
+
 func Test_answersToNetipAddrs(t *testing.T) {
 	t.Parallel()
 
 	testCases := map[string]struct {
-		message    *dns.Msg
-		expected   []netip.Addr
-		errorIsNil bool
+		message  *dns.Msg
+		expected []netip.Addr
 	}{
-		"nil_message": {
-			message:    nil,
-			expected:   nil,
-			errorIsNil: true,
-		},
+		"nil_message": {},
 		"no_answers": {
-			message:    &dns.Msg{},
-			expected:   []netip.Addr{},
-			errorIsNil: true,
+			message:  &dns.Msg{},
+			expected: []netip.Addr{},
 		},
 		"a_record": {
-			message: &dns.Msg{
-				Answer: []dns.RR{
-					&dns.A{
-						Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET},
-						A:   net.IP{1, 1, 1, 1},
-					},
+			message: &dns.Msg{Answer: []dns.RR{
+				&dns.A{
+					Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET},
+					A:   net.IP{1, 1, 1, 1},
 				},
-			},
-			expected:   []netip.Addr{netip.MustParseAddr("1.1.1.1")},
-			errorIsNil: true,
+			}},
+			expected: []netip.Addr{netip.MustParseAddr("1.1.1.1")},
 		},
 		"aaaa_record": {
-			message: &dns.Msg{
-				Answer: []dns.RR{
-					&dns.AAAA{
-						Hdr:  dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeAAAA, Class: dns.ClassINET},
-						AAAA: net.IP{0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0, 0, 0, 0, 0, 0, 0, 0, 0x88, 0x88},
-					},
+			message: &dns.Msg{Answer: []dns.RR{
+				&dns.AAAA{
+					Hdr:  dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeAAAA, Class: dns.ClassINET},
+					AAAA: net.IP{0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0, 0, 0, 0, 0, 0, 0, 0, 0x88, 0x88},
 				},
-			},
-			expected:   []netip.Addr{netip.MustParseAddr("2001:4860:4860::8888")},
-			errorIsNil: true,
+			}},
+			expected: []netip.Addr{netip.MustParseAddr("2001:4860:4860::8888")},
 		},
 		"mixed_records": {
-			message: &dns.Msg{
-				Answer: []dns.RR{
-					&dns.A{
-						Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET},
-						A:   net.IP{1, 1, 1, 1},
-					},
-					&dns.AAAA{
-						Hdr:  dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeAAAA, Class: dns.ClassINET},
-						AAAA: net.IP{0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0, 0, 0, 0, 0, 0, 0, 0, 0x88, 0x88},
-					},
+			message: &dns.Msg{Answer: []dns.RR{
+				&dns.A{
+					Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET},
+					A:   net.IP{1, 1, 1, 1},
 				},
-			},
-			expected:   []netip.Addr{netip.MustParseAddr("1.1.1.1"), netip.MustParseAddr("2001:4860:4860::8888")},
-			errorIsNil: true,
+				&dns.AAAA{
+					Hdr:  dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeAAAA, Class: dns.ClassINET},
+					AAAA: net.IP{0x20, 0x01, 0x48, 0x60, 0x48, 0x60, 0, 0, 0, 0, 0, 0, 0, 0, 0x88, 0x88},
+				},
+			}},
+			expected: []netip.Addr{netip.MustParseAddr("1.1.1.1"), netip.MustParseAddr("2001:4860:4860::8888")},
 		},
 	}
 
 	for testName, testCase := range testCases {
 		t.Run(testName, func(t *testing.T) {
 			t.Parallel()
-
 			addresses := answersToNetipAddrs(testCase.message)
-
 			assert.Equal(t, testCase.expected, addresses)
 		})
 	}

internal/restrictednet/settings.go

@@ -0,0 +1,28 @@
+package restrictednet
+
+import (
+	"errors"
+
+	"github.com/qdm12/dns/v2/pkg/provider"
+)
+
+type Settings struct {
+	DefaultInterface  string
+	IPv6Supported     *bool
+	Firewall          Firewall
+	UpstreamResolvers []provider.Provider
+}
+
+func (s *Settings) validate() error {
+	switch {
+	case s.DefaultInterface == "":
+		return errors.New("default interface is not set")
+	case s.IPv6Supported == nil:
+		return errors.New("IPv6 support field is not set")
+	case s.Firewall == nil:
+		return errors.New("firewall is not set")
+	case len(s.UpstreamResolvers) == 0:
+		return errors.New("no upstream resolvers provided")
+	}
+	return nil
+}