diff options
| -rw-r--r-- | packet/bgp.go | 20 | ||||
| -rw-r--r-- | packet/bgp_test.go | 23 |
2 files changed, 42 insertions, 1 deletions
diff --git a/packet/bgp.go b/packet/bgp.go index 6cc9145d..b95d48f3 100644 --- a/packet/bgp.go +++ b/packet/bgp.go @@ -852,7 +852,7 @@ func getRouteDistinguisher(data []byte) RouteDistinguisherInterface { // // RFC3107 Carrying Label Information in BGP-4 // -// 4. Carrying Label Mapping Information +// 3. Carrying Label Mapping Information // // b) Label: // @@ -872,6 +872,14 @@ func getRouteDistinguisher(data []byte) RouteDistinguisherInterface { // +-----+-+-+---+-+-+-+-+-+-----+-+-+-+ // +// RFC3107 Carrying Label Information in BGP-4 +// +// 3. Carrying Label Mapping Information +// +// The label information carried (as part of NLRI) in the Withdrawn +// Routes field should be set to 0x800000. +const WITHDRAW_LABEL = uint32(0x800000) + type MPLSLabelStack struct { Labels []uint32 } @@ -881,6 +889,10 @@ func (l *MPLSLabelStack) DecodeFromBytes(data []byte) error { foundBottom := false for len(data) >= 3 { label := uint32(data[0])<<16 | uint32(data[1])<<8 | uint32(data[2]) + if label == WITHDRAW_LABEL { + l.Labels = []uint32{label} + return nil + } data = data[3:] labels = append(labels, label>>4) if label&1 == 1 { @@ -899,6 +911,9 @@ func (l *MPLSLabelStack) DecodeFromBytes(data []byte) error { func (l *MPLSLabelStack) Serialize() ([]byte, error) { buf := make([]byte, len(l.Labels)*3) for i, label := range l.Labels { + if label == WITHDRAW_LABEL { + return []byte{128, 0, 0}, nil + } label = label << 4 buf[i*3] = byte((label >> 16) & 0xff) buf[i*3+1] = byte((label >> 8) & 0xff) @@ -911,6 +926,9 @@ func (l *MPLSLabelStack) Serialize() ([]byte, error) { func (l *MPLSLabelStack) Len() int { return 3 * len(l.Labels) } func NewMPLSLabelStack(labels ...uint32) *MPLSLabelStack { + if len(labels) == 0 { + labels = []uint32{0} + } return &MPLSLabelStack{labels} } diff --git a/packet/bgp_test.go b/packet/bgp_test.go index 84aaed75..286bd27c 100644 --- a/packet/bgp_test.go +++ b/packet/bgp_test.go @@ -360,3 +360,26 @@ func Test_ASLen(t *testing.T) { assert.Equal(0, as4path.ASLen()) } + +func Test_MPLSLabelStack(t *testing.T) { + assert := assert.New(t) + mpls := NewMPLSLabelStack() + buf, err := mpls.Serialize() + assert.Nil(err) + assert.Equal(true, bytes.Equal(buf, []byte{0, 0, 1})) + + mpls = &MPLSLabelStack{} + assert.Nil(mpls.DecodeFromBytes(buf)) + assert.Equal(1, len(mpls.Labels)) + assert.Equal(uint32(0), mpls.Labels[0]) + + mpls = NewMPLSLabelStack(WITHDRAW_LABEL) + buf, err = mpls.Serialize() + assert.Nil(err) + assert.Equal(true, bytes.Equal(buf, []byte{128, 0, 0})) + + mpls = &MPLSLabelStack{} + assert.Nil(mpls.DecodeFromBytes(buf)) + assert.Equal(1, len(mpls.Labels)) + assert.Equal(WITHDRAW_LABEL, mpls.Labels[0]) +} |