chore: import upstream snapshot with attribution

internal/util/addr/addr.go

@@ -0,0 +1,165 @@
+// addr provides functions to retrieve local IP addresses from device interfaces.
+package addr
+
+import (
+	"net"
+
+	"github.com/pkg/errors"
+)
+
+var (
+	// ErrIPNotFound no IP address found, and explicit IP not provided.
+	ErrIPNotFound = errors.New("no IP address found, and explicit IP not provided")
+)
+
+// IsLocal checks whether an IP belongs to one of the device's interfaces.
+func IsLocal(addr string) bool {
+	// Extract the host
+	host, _, err := net.SplitHostPort(addr)
+	if err == nil {
+		addr = host
+	}
+
+	if addr == "localhost" {
+		return true
+	}
+
+	// Check against all local ips
+	for _, ip := range IPs() {
+		if addr == ip {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Extract returns a valid IP address. If the address provided is a valid
+// address, it will be returned directly. Otherwise, the available interfaces
+// will be iterated over to find an IP address, preferably private.
+func Extract(addr string) (string, error) {
+	// if addr is already specified then it's directly returned
+	if len(addr) > 0 && (addr != "0.0.0.0" && addr != "[::]" && addr != "::") {
+		return addr, nil
+	}
+
+	var (
+		addrs   []net.Addr
+		loAddrs []net.Addr
+	)
+
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return "", errors.Wrap(err, "failed to get interfaces")
+	}
+
+	for _, iface := range ifaces {
+		ifaceAddrs, err := iface.Addrs()
+		if err != nil {
+			// ignore error, interface can disappear from system
+			continue
+		}
+
+		if iface.Flags&net.FlagLoopback != 0 {
+			loAddrs = append(loAddrs, ifaceAddrs...)
+			continue
+		}
+
+		addrs = append(addrs, ifaceAddrs...)
+	}
+
+	// Add loopback addresses to the end of the list
+	addrs = append(addrs, loAddrs...)
+
+	// Try to find private IP in list, public IP otherwise
+	ip, err := findIP(addrs)
+	if err != nil {
+		return "", err
+	}
+
+	return ip.String(), nil
+}
+
+// IPs returns all available interface IP addresses.
+func IPs() []string {
+	ifaces, err := net.Interfaces()
+	if err != nil {
+		return nil
+	}
+
+	var ipAddrs []string
+
+	for _, i := range ifaces {
+		addrs, err := i.Addrs()
+		if err != nil {
+			continue
+		}
+
+		for _, addr := range addrs {
+			var ip net.IP
+			switch v := addr.(type) {
+			case *net.IPNet:
+				ip = v.IP
+			case *net.IPAddr:
+				ip = v.IP
+			}
+
+			if ip == nil {
+				continue
+			}
+
+			ipAddrs = append(ipAddrs, ip.String())
+		}
+	}
+
+	return ipAddrs
+}
+
+// findIP will return the first private IP available in the list.
+// If no private IP is available it will return the first public IP, if present.
+// If no public IP is available, it will return the first loopback IP, if present.
+func findIP(addresses []net.Addr) (net.IP, error) {
+	var publicIP net.IP
+	var localIP net.IP
+
+	for _, rawAddr := range addresses {
+		var ip net.IP
+		switch addr := rawAddr.(type) {
+		case *net.IPAddr:
+			ip = addr.IP
+		case *net.IPNet:
+			ip = addr.IP
+		default:
+			continue
+		}
+
+		if ip.IsLoopback() {
+			if localIP == nil {
+				localIP = ip
+			}
+			continue
+		}
+
+		if !ip.IsPrivate() {
+			if publicIP == nil {
+				publicIP = ip
+			}
+			continue
+		}
+
+		// Return private IP if available
+		return ip, nil
+	}
+
+	// Return public or virtual IP
+	if len(publicIP) > 0 {
+		return publicIP, nil
+	}
+
+	// Return local IP
+	if len(localIP) > 0 {
+		return localIP, nil
+	}
+
+	return nil, ErrIPNotFound
+}

internal/util/addr/addr_test.go

@@ -0,0 +1,132 @@
+package addr
+
+import (
+	"github.com/stretchr/testify/assert"
+	"net"
+	"testing"
+)
+
+func TestIsLocal(t *testing.T) {
+	testData := []struct {
+		addr   string
+		expect bool
+	}{
+		{"localhost", true},
+		{"localhost:8080", true},
+		{"127.0.0.1", true},
+		{"127.0.0.1:1001", true},
+		{"80.1.1.1", false},
+	}
+
+	for _, d := range testData {
+		res := IsLocal(d.addr)
+		if res != d.expect {
+			t.Fatalf("expected %t got %t", d.expect, res)
+		}
+	}
+}
+
+func TestExtractor(t *testing.T) {
+	testData := []struct {
+		addr   string
+		expect string
+		parse  bool
+	}{
+		{"127.0.0.1", "127.0.0.1", false},
+		{"10.0.0.1", "10.0.0.1", false},
+		{"", "", true},
+		{"0.0.0.0", "", true},
+		{"[::]", "", true},
+	}
+
+	for _, d := range testData {
+		addr, err := Extract(d.addr)
+		if err != nil {
+			t.Errorf("Unexpected error %v", err)
+		}
+
+		if d.parse {
+			ip := net.ParseIP(addr)
+			if ip == nil {
+				t.Error("Unexpected nil IP")
+			}
+		} else if addr != d.expect {
+			t.Errorf("Expected %s got %s", d.expect, addr)
+		}
+	}
+}
+
+func TestFindIP(t *testing.T) {
+	localhost, _ := net.ResolveIPAddr("ip", "127.0.0.1")
+	localhostIPv6, _ := net.ResolveIPAddr("ip", "::1")
+	privateIP, _ := net.ResolveIPAddr("ip", "10.0.0.1")
+	publicIP, _ := net.ResolveIPAddr("ip", "100.0.0.1")
+	publicIPv6, _ := net.ResolveIPAddr("ip", "2001:0db8:85a3:0000:0000:8a2e:0370:7334")
+
+	testCases := []struct {
+		addrs  []net.Addr
+		ip     net.IP
+		errMsg string
+	}{
+		{
+			addrs:  []net.Addr{},
+			ip:     nil,
+			errMsg: ErrIPNotFound.Error(),
+		},
+		{
+			addrs: []net.Addr{localhost},
+			ip:    localhost.IP,
+		},
+		{
+			addrs: []net.Addr{localhost, localhostIPv6},
+			ip:    localhost.IP,
+		},
+		{
+			addrs: []net.Addr{localhostIPv6},
+			ip:    localhostIPv6.IP,
+		},
+		{
+			addrs: []net.Addr{privateIP, localhost},
+			ip:    privateIP.IP,
+		},
+		{
+			addrs: []net.Addr{privateIP, publicIP, localhost},
+			ip:    privateIP.IP,
+		},
+		{
+			addrs: []net.Addr{publicIP, privateIP, localhost},
+			ip:    privateIP.IP,
+		},
+		{
+			addrs: []net.Addr{publicIP, localhost},
+			ip:    publicIP.IP,
+		},
+		{
+			addrs: []net.Addr{publicIP, localhostIPv6},
+			ip:    publicIP.IP,
+		},
+		{
+			addrs: []net.Addr{localhostIPv6, publicIP},
+			ip:    publicIP.IP,
+		},
+		{
+			addrs: []net.Addr{localhostIPv6, publicIPv6, publicIP},
+			ip:    publicIPv6.IP,
+		},
+		{
+			addrs: []net.Addr{publicIP, publicIPv6},
+			ip:    publicIP.IP,
+		},
+	}
+
+	for _, tc := range testCases {
+		ip, err := findIP(tc.addrs)
+		if tc.errMsg == "" {
+			assert.Nil(t, err)
+			assert.Equal(t, tc.ip.String(), ip.String())
+		} else {
+			assert.NotNil(t, err)
+			assert.Equal(t, tc.errMsg, err.Error())
+		}
+	}
+}