testutils_linux_test.go

// +build linux

package secureio_test

import (
	"net"
	"testing"

	"github.com/stretchr/testify/assert"
)

func testUDPPair(t *testing.T) (*net.UDPConn, *net.UDPConn) {
testUDPPairStart:
	localhost := net.ParseIP("127.120.97.105") // just a free address, I hope

	conn0, err := net.DialUDP(`udp`, &net.UDPAddr{IP: localhost}, &net.UDPAddr{IP: localhost})
	assert.NoError(t, err)
	conn1, err := net.DialUDP(`udp`,
		&net.UDPAddr{IP: localhost, Port: 0},
		&net.UDPAddr{IP: localhost, Port: conn0.LocalAddr().(*net.UDPAddr).Port},
	)
	assert.NoError(t, err)
	err = conn0.Close()
	assert.NoError(t, err)
	conn0, err = net.DialUDP(`udp`,
		&net.UDPAddr{IP: localhost, Port: conn1.RemoteAddr().(*net.UDPAddr).Port},
		&net.UDPAddr{IP: localhost, Port: conn1.LocalAddr().(*net.UDPAddr).Port},
	)
	if err != nil {
		goto testUDPPairStart // somebody already took the address
	}

	if t != nil {
		assert.NoError(t, err)

		writeBuf := []byte("abc123")
		_, err = conn1.Write(writeBuf)
		assert.NoError(t, err)
		_, err = conn0.Write(writeBuf)
		assert.NoError(t, err)
		readBuf := make([]byte, 65536)
		n, err := conn0.Read(readBuf)
		assert.NoError(t, err)
		assert.Equal(t, writeBuf, readBuf[:n])
	}

	return conn0, conn1
}