Add support for domain fronting proxy protocol

mtglib/conns_internal_test.go

@@ -1,14 +1,17 @@
 package mtglib
 
 import (
+	"bufio"
 	"bytes"
 	"context"
 	"errors"
 	"io"
+	"net"
 	"testing"
 	"time"
 
 	"github.com/9seconds/mtg/v2/internal/testlib"
+	"github.com/pires/go-proxyproto"
 	"github.com/stretchr/testify/mock"
 	"github.com/stretchr/testify/suite"
 )
@@ -200,6 +203,94 @@ func (suite *ConnRewindTestSuite) TestRead() {
 	suite.Equal([]byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, data)
 }
 
+type ConnProxyProtocolTestSuite struct {
+	suite.Suite
+
+	sourceConnMock *testlib.EssentialsConnMock
+	targetConnMock *testlib.EssentialsConnMock
+	conn           *connProxyProtocol
+}
+
+func (suite *ConnProxyProtocolTestSuite) SetupTest() {
+	suite.sourceConnMock = &testlib.EssentialsConnMock{}
+	suite.targetConnMock = &testlib.EssentialsConnMock{}
+
+	localAddr := &net.TCPAddr{
+		IP: net.ParseIP("127.0.0.1").To4(),
+	}
+	remoteAddr := &net.TCPAddr{
+		IP: net.ParseIP("127.0.0.2").To4(),
+	}
+
+	suite.sourceConnMock.
+		On("RemoteAddr").
+		Return(localAddr)
+	suite.targetConnMock.
+		On("RemoteAddr").
+		Maybe().
+		Return(remoteAddr)
+
+	suite.conn = newConnProxyProtocol(suite.sourceConnMock, suite.targetConnMock)
+}
+
+func (suite *ConnProxyProtocolTestSuite) TestRead() {
+	value := []byte{1, 2, 3, 4, 5}
+	toRead := make([]byte, len(value))
+
+	suite.targetConnMock.
+		On("Read", mock.AnythingOfType("[]uint8")).
+		Once().
+		Return(len(toRead), nil).
+		Run(func(args mock.Arguments) {
+			arr := args.Get(0).([]byte)
+			copy(arr, value)
+		})
+
+	n, err := suite.conn.Read(toRead)
+	suite.Equal(len(value), n)
+	suite.NoError(err)
+	suite.Equal(value, toRead)
+}
+
+func (suite *ConnProxyProtocolTestSuite) TestWrite() {
+	value := []byte{1, 2, 3, 4, 5}
+	buf := &bytes.Buffer{}
+	bufReader := bufio.NewReader(buf)
+
+	suite.targetConnMock.
+		On("Write", mock.AnythingOfType("[]uint8")).
+		Return(28, nil).
+		Run(func(args mock.Arguments) {
+			arr := args.Get(0).([]byte)
+			buf.Write(arr)
+		})
+
+	_, err := suite.conn.Write(value)
+	suite.NoError(err)
+
+	header, err := proxyproto.Read(bufReader)
+	suite.NoError(err)
+
+	sourceAddr, destAddr, ok := header.TCPAddrs()
+	suite.True(ok)
+	suite.Equal(suite.sourceConnMock.RemoteAddr(), sourceAddr)
+	suite.Equal(suite.targetConnMock.RemoteAddr(), destAddr)
+
+	read, _ := io.ReadAll(bufReader)
+	suite.Equal(value, read)
+
+	_, err = suite.conn.Write(value)
+	suite.NoError(err)
+
+	read, _ = io.ReadAll(bufReader)
+	suite.Equal(value, read)
+}
+
+func (suite *ConnProxyProtocolTestSuite) TearDownTest() {
+	suite.sourceConnMock.AssertExpectations(suite.T())
+	suite.targetConnMock.AssertExpectations(suite.T())
+}
+
 func TestConnTraffic(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ConnTrafficTestSuite{})
@@ -209,3 +300,8 @@ func TestConnRewind(t *testing.T) {
 	t.Parallel()
 	suite.Run(t, &ConnRewindTestSuite{})
 }
+
+func TestConnProxyProtocol(t *testing.T) {
+	t.Parallel()
+	suite.Run(t, &ConnProxyProtocolTestSuite{})
+}