bgp: fix bug of route target membershop nlri

RFC4760 says NLRI Encoding is encoded as 2-tuples of the form <length, prefix>
this patch adds Length fields to the RouteTargetMembershopNLRI

Signed-off-by: ISHIDA Wataru <ishida.wataru@lab.ntt.co.jp>

2 files changed, 92 insertions, 40 deletions

diff --git a/packet/bgp.go b/packet/bgp.go
index fa495edd..096444dc 100644
--- a/packet/bgp.go
+++ b/packet/bgp.go
@@ -1046,11 +1046,19 @@ func NewLabelledIPv6AddrPrefix(length uint8, prefix string, label Label) *Labell
 }
 
 type RouteTargetMembershipNLRI struct {
+	Length      uint8
 	AS          uint32
 	RouteTarget ExtendedCommunityInterface
 }
 
 func (n *RouteTargetMembershipNLRI) DecodeFromBytes(data []byte) error {
+	n.Length = data[0]
+	data = data[1:]
+	if len(data) == 0 {
+		return nil
+	} else if len(data) != 12 {
+		return fmt.Errorf("Not all RouteTargetMembershipNLRI bytes available")
+	}
 	n.AS = binary.BigEndian.Uint32(data[0:4])
 	rt, err := parseExtended(data[4:])
 	n.RouteTarget = rt
@@ -1061,13 +1069,18 @@ func (n *RouteTargetMembershipNLRI) DecodeFromBytes(data []byte) error {
 }
 
 func (n *RouteTargetMembershipNLRI) Serialize() ([]byte, error) {
-	buf := make([]byte, 4)
-	binary.BigEndian.PutUint32(buf, n.AS)
+	if n.RouteTarget == nil {
+		return []byte{0}, nil
+	}
+	buf := make([]byte, 5)
+	buf[0] = 12 * 8
+	binary.BigEndian.PutUint32(buf[1:], n.AS)
 	ebuf, err := n.RouteTarget.Serialize()
 	if err != nil {
 		return nil, err
 	}
-	return append(buf, ebuf...), nil
+	buf = append(buf, ebuf...)
+	return buf, nil
 }
 
 func (n *RouteTargetMembershipNLRI) AFI() uint16 {
@@ -1078,7 +1091,12 @@ func (n *RouteTargetMembershipNLRI) SAFI() uint8 {
 	return SAFI_ROUTE_TARGET_CONSTRTAINS
 }
 
-func (n *RouteTargetMembershipNLRI) Len() int { return 12 }
+func (n *RouteTargetMembershipNLRI) Len() int {
+	if n.AS == 0 && n.RouteTarget == nil {
+		return 1
+	}
+	return 13
+}
 
 func (n *RouteTargetMembershipNLRI) String() string {
 	return fmt.Sprintf("%d:%s/%d", n.AS, n.RouteTarget.String(), n.Len()*8)
diff --git a/packet/bgp_test.go b/packet/bgp_test.go
index 839d8f23..3b5d7b4c 100644
--- a/packet/bgp_test.go
+++ b/packet/bgp_test.go
@@ -170,54 +170,88 @@ func Test_IPAddrPrefixString(t *testing.T) {
 }
 
 func Test_RouteTargetMembershipNLRIString(t *testing.T) {
-	r := &RouteTargetMembershipNLRI{}
-
 	assert := assert.New(t)
 
 	// TwoOctetAsSpecificExtended
-	buf := make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], 65546)
-	buf[4] = byte(EC_TYPE_TRANSITIVE_TWO_OCTET_AS_SPECIFIC) // typehigh
-	binary.BigEndian.PutUint16(buf[6:8], 65000)
-	binary.BigEndian.PutUint32(buf[8:], 65546)
-	r.DecodeFromBytes(buf)
-	assert.Equal("65546:65000:65546/96", r.String())
+	buf := make([]byte, 13)
+	buf[0] = 12
+	binary.BigEndian.PutUint32(buf[1:5], 65546)
+	buf[5] = byte(EC_TYPE_TRANSITIVE_TWO_OCTET_AS_SPECIFIC) // typehigh
+	binary.BigEndian.PutUint16(buf[7:9], 65000)
+	binary.BigEndian.PutUint32(buf[9:], 65546)
+	r := &RouteTargetMembershipNLRI{}
+	err := r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:65000:65546", r.String())
+	buf, err = r.Serialize()
+	assert.Equal(nil, err)
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:65000:65546", r.String())
 
 	// IPv4AddressSpecificExtended
-	buf = make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], 65546)
-	buf[4] = byte(EC_TYPE_TRANSITIVE_IP4_SPECIFIC) // typehigh
+	buf = make([]byte, 13)
+	binary.BigEndian.PutUint32(buf[1:5], 65546)
+	buf[5] = byte(EC_TYPE_TRANSITIVE_IP4_SPECIFIC) // typehigh
 	ip := net.ParseIP("10.0.0.1").To4()
-	copy(buf[6:10], []byte(ip))
-	binary.BigEndian.PutUint16(buf[10:], 65000)
-	r.DecodeFromBytes(buf)
-	assert.Equal("65546:10.0.0.1:65000/96", r.String())
+	copy(buf[7:11], []byte(ip))
+	binary.BigEndian.PutUint16(buf[11:], 65000)
+	r = &RouteTargetMembershipNLRI{}
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:10.0.0.1:65000", r.String())
+	buf, err = r.Serialize()
+	assert.Equal(nil, err)
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:10.0.0.1:65000", r.String())
 
 	// FourOctetAsSpecificExtended
-	buf = make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], 65546)
-	buf[4] = byte(EC_TYPE_TRANSITIVE_FOUR_OCTET_AS_SPECIFIC) // typehigh
-	buf[5] = byte(EC_SUBTYPE_ROUTE_TARGET)                   // subtype
-	binary.BigEndian.PutUint32(buf[6:], 65546)
-	binary.BigEndian.PutUint16(buf[10:], 65000)
-	r.DecodeFromBytes(buf)
-	assert.Equal("65546:1.10:65000/96", r.String())
+	buf = make([]byte, 13)
+	binary.BigEndian.PutUint32(buf[1:5], 65546)
+	buf[5] = byte(EC_TYPE_TRANSITIVE_FOUR_OCTET_AS_SPECIFIC) // typehigh
+	buf[6] = byte(EC_SUBTYPE_ROUTE_TARGET)                   // subtype
+	binary.BigEndian.PutUint32(buf[7:], 65546)
+	binary.BigEndian.PutUint16(buf[11:], 65000)
+	r = &RouteTargetMembershipNLRI{}
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1.10:65000", r.String())
+	buf, err = r.Serialize()
+	assert.Equal(nil, err)
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1.10:65000", r.String())
 
 	// OpaqueExtended
-	buf = make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], 65546)
-	buf[4] = byte(EC_TYPE_TRANSITIVE_OPAQUE) // typehigh
-	binary.BigEndian.PutUint32(buf[8:], 1000000)
-	r.DecodeFromBytes(buf)
-	assert.Equal("65546:1000000/96", r.String())
+	buf = make([]byte, 13)
+	binary.BigEndian.PutUint32(buf[1:5], 65546)
+	buf[5] = byte(EC_TYPE_TRANSITIVE_OPAQUE) // typehigh
+	binary.BigEndian.PutUint32(buf[9:], 1000000)
+	r = &RouteTargetMembershipNLRI{}
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1000000", r.String())
+	buf, err = r.Serialize()
+	assert.Equal(nil, err)
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1000000", r.String())
 
 	// Unknown
-	buf = make([]byte, 12)
-	binary.BigEndian.PutUint32(buf[:4], 65546)
-	buf[4] = 0x04 // typehigh
-	binary.BigEndian.PutUint32(buf[8:], 1000000)
-	r.DecodeFromBytes(buf)
-	assert.Equal("65546:1000000/96", r.String())
+	buf = make([]byte, 13)
+	binary.BigEndian.PutUint32(buf[1:5], 65546)
+	buf[5] = 0x04 // typehigh
+	binary.BigEndian.PutUint32(buf[9:], 1000000)
+	r = &RouteTargetMembershipNLRI{}
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1000000", r.String())
+	buf, err = r.Serialize()
+	assert.Equal(nil, err)
+	err = r.DecodeFromBytes(buf)
+	assert.Equal(nil, err)
+	assert.Equal("65546:1000000", r.String())
 
 }