added add community action

routingtable/filter/actions/add_community_action.go

+package actions
+
+import (
+	"strings"
+
+	"github.com/bio-routing/bio-rd/net"
+	"github.com/bio-routing/bio-rd/protocols/bgp/packet"
+	"github.com/bio-routing/bio-rd/route"
+)
+
+type AddCommunityAction struct {
+	communities []uint32
+}
+
+func NewAddCommunityAction(coms []uint32) *AddCommunityAction {
+	return &AddCommunityAction{
+		communities: coms,
+	}
+}
+
+func (a *AddCommunityAction) Do(p net.Prefix, pa *route.Path) (modPath *route.Path, reject bool) {
+	if pa.BGPPath == nil || len(a.communities) == 0 {
+		return pa, false
+	}
+
+	modified := pa.Copy()
+
+	for _, com := range a.communities {
+		modified.BGPPath.Communities = modified.BGPPath.Communities + " " + packet.CommunityStringForUint32(com)
+	}
+	modified.BGPPath.Communities = strings.TrimLeft(modified.BGPPath.Communities, " ")
+
+	return modified, false
+}

routingtable/filter/actions/add_community_action_test.go

+package actions
+
+import (
+	"testing"
+
+	"github.com/bio-routing/bio-rd/net"
+	"github.com/bio-routing/bio-rd/route"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAddingCommunities(t *testing.T) {
+	tests := []struct {
+		name        string
+		current     string
+		communities []uint32
+		expected    string
+	}{
+		{
+			name: "add one to empty",
+			communities: []uint32{
+				65538,
+			},
+			expected: "(1,2)",
+		},
+		{
+			name:    "add one to existing",
+			current: "(1,2)",
+			communities: []uint32{
+				196612,
+			},
+			expected: "(1,2) (3,4)",
+		},
+		{
+			name:    "add two to existing",
+			current: "(1,2)",
+			communities: []uint32{
+				196612, 327686,
+			},
+			expected: "(1,2) (3,4) (5,6)",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(te *testing.T) {
+			p := &route.Path{
+				BGPPath: &route.BGPPath{
+					Communities: test.current,
+				},
+			}
+
+			a := NewAddCommunityAction(test.communities)
+			modPath, _ := a.Do(net.Prefix{}, p)
+
+			assert.Equal(te, test.expected, modPath.BGPPath.Communities)
+		})
+	}
+}