bgp: remove duplicate large communities

closes #1143

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

2 files changed, 30 insertions, 0 deletions

diff --git a/packet/bgp/validate.go b/packet/bgp/validate.go
index da7aa5fc..5cf2afbb 100644
--- a/packet/bgp/validate.go
+++ b/packet/bgp/validate.go
@@ -159,6 +159,21 @@ func ValidateAttribute(a PathAttributeInterface, rfs map[RouteFamily]bool, doCon
 				}
 			}
 		}
+	case *PathAttributeLargeCommunities:
+		uniq := make([]*LargeCommunity, 0, len(p.Values))
+		for _, x := range p.Values {
+			found := false
+			for _, y := range uniq {
+				if x.String() == y.String() {
+					found = true
+					break
+				}
+			}
+			if !found {
+				uniq = append(uniq, x)
+			}
+		}
+		p.Values = uniq
 
 	case *PathAttributeUnknown:
 		if p.GetFlags()&BGP_ATTR_FLAG_OPTIONAL == 0 {
diff --git a/packet/bgp/validate_test.go b/packet/bgp/validate_test.go
index 66eb56d5..225f941d 100644
--- a/packet/bgp/validate_test.go
+++ b/packet/bgp/validate_test.go
@@ -384,3 +384,18 @@ func Test_Validate_flowspec(t *testing.T) {
 	_, err = ValidateAttribute(a, m, false)
 	assert.NotNil(err)
 }
+
+func TestValidateLargeCommunities(t *testing.T) {
+	assert := assert.New(t)
+	c1, err := ParseLargeCommunity("10:10:10")
+	assert.Nil(err)
+	c2, err := ParseLargeCommunity("10:10:10")
+	assert.Nil(err)
+	c3, err := ParseLargeCommunity("10:10:20")
+	assert.Nil(err)
+	a := NewPathAttributeLargeCommunities([]*LargeCommunity{c1, c2, c3})
+	assert.True(len(a.Values) == 3)
+	_, err = ValidateAttribute(a, nil, false)
+	assert.Nil(err)
+	assert.True(len(a.Values) == 2)
+}