Merge pull request #85 from bio-routing/fix/aggregation

Fixing AGGREGATOR and ATOMIC_AGGREGATE

protocols/bgp/packet/bgp.go

@@ -140,8 +140,3 @@ type PathAttribute struct {
 	Value          interface{}
 	Next           *PathAttribute
 }
-
-type Aggretator struct {
-	Addr uint32
-	ASN  uint16
-}

protocols/bgp/packet/decoder_test.go

@@ -1195,9 +1195,9 @@ func TestDecodeUpdateMsg(t *testing.T) {
 											ExtendedLength: false,
 											Length:         6,
 											TypeCode:       7,
-											Value: Aggretator{
+											Value: types.Aggregator{
 												ASN:     uint16(258),
-												Addr: strAddr("10.11.12.13"),
+												Address: strAddr("10.11.12.13"),
 											},
 										},
 									},

protocols/bgp/packet/path_attributes.go

@@ -224,28 +224,15 @@ func (pa *PathAttribute) decodeLocalPref(buf *bytes.Buffer) error {
 }
 
 func (pa *PathAttribute) decodeAggregator(buf *bytes.Buffer) error {
-	aggr := Aggretator{}
+	aggr := types.Aggregator{}
 	p := uint16(0)
 
-	err := decode(buf, []interface{}{&aggr.ASN})
+	err := decode(buf, []interface{}{&aggr.ASN, &aggr.Address})
 	if err != nil {
 		return err
 	}
-	p += 2
-
-	addr := [4]byte{}
-	n, err := buf.Read(addr[:])
-	if err != nil {
-		return err
-	}
-	if n != 4 {
-		return fmt.Errorf("Unable to read next hop: buf.Read read %d bytes", n)
-	}
-	aggr.Addr = fourBytesToUint32(addr)
-
+	p += 6
 	pa.Value = aggr
-	p += 4
-
 	return dumpNBytes(buf, pa.Length-p)
 }
 
@@ -497,10 +484,14 @@ func (pa *PathAttribute) serializeAggregator(buf *bytes.Buffer) uint8 {
 	attrFlags = setTransitive(attrFlags)
 	buf.WriteByte(attrFlags)
 	buf.WriteByte(AggregatorAttr)
-	length := uint8(2)
+	length := uint8(6)
 	buf.WriteByte(length)
-	buf.Write(convert.Uint16Byte(pa.Value.(uint16)))
-	return 5
+
+	aggregator := pa.Value.(types.Aggregator)
+	buf.Write(convert.Uint16Byte(aggregator.ASN))
+	buf.Write(convert.Uint32Byte(aggregator.Address))
+
+	return 9
 }
 
 func (pa *PathAttribute) serializeCommunities(buf *bytes.Buffer) uint8 {
@@ -622,33 +613,56 @@ func (pa *PathAttribute) AddOptionalPathAttributes(p *route.Path) *PathAttribute
 }
 
 // PathAttributes converts a path object into a linked list of path attributes
-func PathAttributes(p *route.Path) (*PathAttribute, error) {
+func PathAttributes(p *route.Path, iBGP bool) (*PathAttribute, error) {
 	asPath := &PathAttribute{
 		TypeCode: ASPathAttr,
 		Value:    p.BGPPath.ASPath,
 	}
+	last := asPath
 
 	origin := &PathAttribute{
 		TypeCode: OriginAttr,
 		Value:    p.BGPPath.Origin,
 	}
-	asPath.Next = origin
+	last.Next = origin
+	last = origin
 
 	nextHop := &PathAttribute{
 		TypeCode: NextHopAttr,
 		Value:    p.BGPPath.NextHop,
 	}
-	origin.Next = nextHop
+	last.Next = nextHop
+	last = nextHop
+
+	if p.BGPPath.AtomicAggregate {
+		atomicAggr := &PathAttribute{
+			TypeCode: AtomicAggrAttr,
+		}
+		last.Next = atomicAggr
+		last = atomicAggr
+	}
 
+	if p.BGPPath.Aggregator != nil {
+		aggregator := &PathAttribute{
+			TypeCode: AggregatorAttr,
+			Value:    p.BGPPath.Aggregator,
+		}
+		last.Next = aggregator
+		last = aggregator
+	}
+
+	if iBGP {
 		localPref := &PathAttribute{
 			TypeCode: LocalPrefAttr,
 			Value:    p.BGPPath.LocalPref,
 		}
-	nextHop.Next = localPref
+		last.Next = localPref
+		last = localPref
+	}
 
-	optionals := localPref.AddOptionalPathAttributes(p)
+	optionals := last.AddOptionalPathAttributes(p)
 
-	last := optionals
+	last = optionals
 	for _, unknownAttr := range p.BGPPath.UnknownAttributes {
 		last.Next = &PathAttribute{
 			TypeCode:   unknownAttr.TypeCode,

protocols/bgp/packet/path_attributes_test.go

@@ -563,9 +563,9 @@ func TestDecodeAggregator(t *testing.T) {
 			wantFail: false,
 			expected: &PathAttribute{
 				Length: 6,
-				Value: Aggretator{
+				Value: types.Aggregator{
 					ASN:     222,
-					Addr: strAddr("10.20.30.40"),
+					Address: strAddr("10.20.30.40"),
 				},
 			},
 		},
@@ -1137,15 +1137,19 @@ func TestSerializeAggregator(t *testing.T) {
 			name: "Test #1",
 			input: &PathAttribute{
 				TypeCode: AggregatorAttr,
-				Value:    uint16(174),
+				Value: types.Aggregator{
+					ASN:     174,
+					Address: strAddr("10.20.30.40"),
+				},
 			},
 			expected: []byte{
 				192,    // Attribute flags
 				7,      // Type
-				2,      // Length
+				6,      // Length
 				0, 174, // Value = 174
+				10, 20, 30, 40,
 			},
-			expectedLen: 5,
+			expectedLen: 9,
 		},
 	}
 
@@ -1510,7 +1514,10 @@ func TestSerialize(t *testing.T) {
 										TypeCode: AtomicAggrAttr,
 										Next: &PathAttribute{
 											TypeCode: AggregatorAttr,
-											Value:    uint16(200),
+											Value: types.Aggregator{
+												ASN:     200,
+												Address: strAddr("10.20.30.40"),
+											},
 										},
 									},
 								},
@@ -1529,7 +1536,7 @@ func TestSerialize(t *testing.T) {
 			},
 			expected: []byte{
 				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-				0, 86, // Length
+				0, 90, // Length
 				2, // Msg Type
 
 				// Withdraws
@@ -1537,7 +1544,7 @@ func TestSerialize(t *testing.T) {
 				8, 10, // Withdraw 10/8
 				16, 192, 168, // Withdraw 192.168/16
 
-				0, 50, // Total Path Attribute Length
+				0, 54, // Total Path Attribute Length
 
 				// ORIGIN
 				64, // Attr. Flags
@@ -1576,8 +1583,9 @@ func TestSerialize(t *testing.T) {
 				// Aggregator
 				192,    // Attr. Flags
 				7,      // Attr. Type Code
-				2,      // Length
+				6,      // Length
 				0, 200, // Aggregator ASN = 200
+				10, 20, 30, 40, // Aggregator Address
 
 				// NLRI
 				24, 8, 8, 8, // 8.8.8.0/24
@@ -1715,7 +1723,10 @@ func TestSerializeAddPath(t *testing.T) {
 										TypeCode: AtomicAggrAttr,
 										Next: &PathAttribute{
 											TypeCode: AggregatorAttr,
-											Value:    uint16(200),
+											Value: types.Aggregator{
+												ASN:     200,
+												Address: strAddr("10.20.30.40"),
+											},
 										},
 									},
 								},
@@ -1734,7 +1745,7 @@ func TestSerializeAddPath(t *testing.T) {
 			},
 			expected: []byte{
 				0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
-				0, 102, // Length
+				0, 106, // Length
 				2, // Msg Type
 
 				// Withdraws
@@ -1744,7 +1755,7 @@ func TestSerializeAddPath(t *testing.T) {
 				0, 0, 0, 0, // Path Identifier
 				16, 192, 168, // Withdraw 192.168/16
 
-				0, 50, // Total Path Attribute Length
+				0, 54, // Total Path Attribute Length
 
 				// ORIGIN
 				64, // Attr. Flags
@@ -1783,8 +1794,9 @@ func TestSerializeAddPath(t *testing.T) {
 				// Aggregator
 				192,    // Attr. Flags
 				7,      // Attr. Type Code
-				2,      // Length
+				6,      // Length
 				0, 200, // Aggregator ASN = 200
+				10, 20, 30, 40, // Aggregator Address
 
 				// NLRI
 				0, 0, 0, 0, // Path Identifier

protocols/bgp/server/fsm_established.go

@@ -244,6 +244,11 @@ func (s *establishedState) processAttributes(attrs *packet.PathAttribute, path *
 		case packet.ASPathAttr:
 			path.BGPPath.ASPath = pa.Value.(types.ASPath)
 			path.BGPPath.ASPathLen = path.BGPPath.ASPath.Length()
+		case packet.AggregatorAttr:
+			aggr := pa.Value.(types.Aggregator)
+			path.BGPPath.Aggregator = &aggr
+		case packet.AtomicAggrAttr:
+			path.BGPPath.AtomicAggregate = true
 		case packet.CommunitiesAttr:
 			path.BGPPath.Communities = pa.Value.([]uint32)
 		case packet.LargeCommunitiesAttr:

protocols/bgp/server/update_sender.go

@@ -86,7 +86,7 @@ func (u *UpdateSender) sender(aggrTime time.Duration) {
 
 		for key, pathNLRIs := range u.toSend {
 			budget = packet.MaxLen - packet.HeaderLen - packet.MinUpdateLen - int(pathNLRIs.path.BGPPath.Length())
-			pathAttrs, err = packet.PathAttributes(pathNLRIs.path)
+			pathAttrs, err = packet.PathAttributes(pathNLRIs.path, u.iBGP)
 			if err != nil {
 				log.Errorf("Unable to get path attributes: %v", err)
 				continue

protocols/bgp/types/BUILD.bazel

@@ -3,6 +3,7 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
+        "aggregator.go",
         "as_path.go",
         "community.go",
         "large_community.go",

protocols/bgp/types/aggregator.go

+package types
+
+// Aggregator represents an AGGREGATOR attribute (type code 7) as in RFC4271
+type Aggregator struct {
+	ASN     uint16
+	Address uint32
+}

route/bgp_path.go

@@ -19,6 +19,8 @@ type BGPPath struct {
 	Origin            uint8
 	MED               uint32
 	EBGP              bool
+	AtomicAggregate   bool
+	Aggregator        *types.Aggregator
 	BGPIdentifier     uint32
 	Source            uint32
 	Communities       []uint32