Golang bgp.NewPathAttributeAsPath函数代码示例

func TestImplicitWithdrawCalculate(t *testing.T) {
	origin := bgp.NewPathAttributeOrigin(0)
	aspathParam := []bgp.AsPathParamInterface{bgp.NewAs4PathParam(2, []uint32{65001})}
	aspath := bgp.NewPathAttributeAsPath(aspathParam)
	nexthop := bgp.NewPathAttributeNextHop("10.0.0.1")
	med := bgp.NewPathAttributeMultiExitDisc(0)
	pathAttributes := []bgp.PathAttributeInterface{origin, aspath, nexthop, med}
	nlri := bgp.NewIPAddrPrefix(24, "10.10.0.101")
	updateMsg := bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	peer1 := &PeerInfo{AS: 1, Address: net.IP{1, 1, 1, 1}}
	path1 := ProcessMessage(updateMsg, peer1, time.Now())[0]
	path1.Filter("1", POLICY_DIRECTION_IMPORT)

	// suppose peer2 has import policy to prepend as-path
	action := &AsPathPrependAction{
		asn:    100,
		repeat: 1,
	}

	path2 := action.Apply(path1.Clone(false), nil)
	path1.Filter("2", POLICY_DIRECTION_IMPORT)
	path2.Filter("1", POLICY_DIRECTION_IMPORT)
	path2.Filter("3", POLICY_DIRECTION_IMPORT)

	d := NewDestination(nlri)
	d.AddNewPath(path1)
	d.AddNewPath(path2)

	d.Calculate(nil)

	assert.Equal(t, len(d.GetKnownPathList("1")), 0) // peer "1" is the originator
	assert.Equal(t, len(d.GetKnownPathList("2")), 1)
	assert.Equal(t, d.GetKnownPathList("2")[0].GetAsString(), "100 65001") // peer "2" has modified path {100, 65001}
	assert.Equal(t, len(d.GetKnownPathList("3")), 1)
	assert.Equal(t, d.GetKnownPathList("3")[0].GetAsString(), "65001") // peer "3" has original path {65001}
	assert.Equal(t, len(d.knownPathList), 2)

	// say, we removed peer2's import policy and
	// peer1 advertised new path with the same prefix
	aspathParam = []bgp.AsPathParamInterface{bgp.NewAs4PathParam(2, []uint32{65001, 65002})}
	aspath = bgp.NewPathAttributeAsPath(aspathParam)
	pathAttributes = []bgp.PathAttributeInterface{origin, aspath, nexthop, med}
	updateMsg = bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	path3 := ProcessMessage(updateMsg, peer1, time.Now())[0]
	path3.Filter("1", POLICY_DIRECTION_IMPORT)

	d.AddNewPath(path3)
	d.Calculate(nil)

	assert.Equal(t, len(d.GetKnownPathList("1")), 0) // peer "1" is the originator
	assert.Equal(t, len(d.GetKnownPathList("2")), 1)
	assert.Equal(t, d.GetKnownPathList("2")[0].GetAsString(), "65001 65002") // peer "2" has new original path {65001, 65002}
	assert.Equal(t, len(d.GetKnownPathList("3")), 1)
	assert.Equal(t, d.GetKnownPathList("3")[0].GetAsString(), "65001 65002") // peer "3" has new original path {65001, 65002}
	assert.Equal(t, len(d.knownPathList), 1)
}

func TestMedTieBreaker(t *testing.T) {
	nlri := bgp.NewIPAddrPrefix(24, "10.10.0.0")

	p0 := func() *Path {
		aspath := bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65001, 65002}), bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65003, 65004})})
		attrs := []bgp.PathAttributeInterface{aspath, bgp.NewPathAttributeMultiExitDisc(0)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	p1 := func() *Path {
		aspath := bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65001, 65002}), bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65003, 65005})})
		attrs := []bgp.PathAttributeInterface{aspath, bgp.NewPathAttributeMultiExitDisc(10)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	// same AS
	assert.Equal(t, compareByMED(p0, p1), p0)

	p2 := func() *Path {
		aspath := bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65003})})
		attrs := []bgp.PathAttributeInterface{aspath, bgp.NewPathAttributeMultiExitDisc(10)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	// different AS
	assert.Equal(t, compareByMED(p0, p2), (*Path)(nil))

	p3 := func() *Path {
		aspath := bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ, []uint32{65003, 65004}), bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65001, 65003})})
		attrs := []bgp.PathAttributeInterface{aspath, bgp.NewPathAttributeMultiExitDisc(0)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	p4 := func() *Path {
		aspath := bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{65001, 65002}), bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ, []uint32{65005, 65006})})
		attrs := []bgp.PathAttributeInterface{aspath, bgp.NewPathAttributeMultiExitDisc(10)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	// ignore confed
	assert.Equal(t, compareByMED(p3, p4), p3)

	p5 := func() *Path {
		attrs := []bgp.PathAttributeInterface{bgp.NewPathAttributeMultiExitDisc(0)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	p6 := func() *Path {
		attrs := []bgp.PathAttributeInterface{bgp.NewPathAttributeMultiExitDisc(10)}
		return NewPath(nil, nlri, false, attrs, time.Now(), false)
	}()

	// no aspath
	assert.Equal(t, compareByMED(p5, p6), p5)
}

func TestMrtRib(t *testing.T) {
	aspath1 := []bgp.AsPathParamInterface{
		bgp.NewAsPathParam(2, []uint16{1000}),
		bgp.NewAsPathParam(1, []uint16{1001, 1002}),
		bgp.NewAsPathParam(2, []uint16{1003, 1004}),
	}

	p := []bgp.PathAttributeInterface{
		bgp.NewPathAttributeOrigin(3),
		bgp.NewPathAttributeAsPath(aspath1),
		bgp.NewPathAttributeNextHop("129.1.1.2"),
		bgp.NewPathAttributeMultiExitDisc(1 << 20),
		bgp.NewPathAttributeLocalPref(1 << 22),
	}

	e1 := NewRibEntry(1, uint32(time.Now().Unix()), p)
	e2 := NewRibEntry(2, uint32(time.Now().Unix()), p)
	e3 := NewRibEntry(3, uint32(time.Now().Unix()), p)

	r1 := NewRib(1, bgp.NewIPAddrPrefix(24, "192.168.0.0"), []*RibEntry{e1, e2, e3})
	b1, err := r1.Serialize()
	if err != nil {
		t.Fatal(err)
	}
	r2 := &Rib{
		RouteFamily: bgp.RF_IPv4_UC,
	}
	err = r2.DecodeFromBytes(b1)
	if err != nil {
		t.Fatal(err)
	}
	assert.Equal(t, reflect.DeepEqual(r1, r2), true)
}

func TestMrtRibEntry(t *testing.T) {
	aspath1 := []bgp.AsPathParamInterface{
		bgp.NewAsPathParam(2, []uint16{1000}),
		bgp.NewAsPathParam(1, []uint16{1001, 1002}),
		bgp.NewAsPathParam(2, []uint16{1003, 1004}),
	}

	p := []bgp.PathAttributeInterface{
		bgp.NewPathAttributeOrigin(3),
		bgp.NewPathAttributeAsPath(aspath1),
		bgp.NewPathAttributeNextHop("129.1.1.2"),
		bgp.NewPathAttributeMultiExitDisc(1 << 20),
		bgp.NewPathAttributeLocalPref(1 << 22),
	}

	e1 := NewRibEntry(1, uint32(time.Now().Unix()), p)
	b1, err := e1.Serialize()
	if err != nil {
		t.Fatal(err)
	}

	e2 := &RibEntry{}
	rest, err := e2.DecodeFromBytes(b1)
	if err != nil {
		t.Fatal(err)
	}
	assert.Equal(t, len(rest), 0)
	assert.Equal(t, reflect.DeepEqual(e1, e2), true)
}

func strToASParam(str string) *bgp.PathAttributeAsPath {
	toList := func(asstr, sep string) []uint32 {
		as := make([]uint32, 0)
		l := strings.Split(asstr, sep)
		for _, s := range l {
			v, _ := strconv.ParseUint(s, 10, 32)
			as = append(as, uint32(v))
		}
		return as
	}
	var atype uint8
	var as []uint32
	if strings.HasPrefix(str, "{") {
		atype = bgp.BGP_ASPATH_ATTR_TYPE_SET
		as = toList(str[1:len(str)-1], ",")
	} else if strings.HasPrefix(str, "(") {
		atype = bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET
		as = toList(str[1:len(str)-1], " ")
	} else {
		atype = bgp.BGP_ASPATH_ATTR_TYPE_SEQ
		as = toList(str, " ")
	}

	return bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(atype, as)})
}

func TestASPathLen(t *testing.T) {
	assert := assert.New(t)
	origin := bgp.NewPathAttributeOrigin(0)
	aspathParam := []bgp.AsPathParamInterface{
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint16{65001, 65002, 65003, 65004, 65004, 65004, 65004, 65004, 65005}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_SET, []uint16{65001, 65002, 65003, 65004, 65005}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ, []uint16{65100, 65101, 65102}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET, []uint16{65100, 65101})}
	aspath := bgp.NewPathAttributeAsPath(aspathParam)
	nexthop := bgp.NewPathAttributeNextHop("192.168.50.1")
	med := bgp.NewPathAttributeMultiExitDisc(0)

	pathAttributes := []bgp.PathAttributeInterface{
		origin,
		aspath,
		nexthop,
		med,
	}

	nlri := []*bgp.IPAddrPrefix{bgp.NewIPAddrPrefix(24, "10.10.10.0")}
	bgpmsg := bgp.NewBGPUpdateMessage(nil, pathAttributes, nlri)
	update := bgpmsg.Body.(*bgp.BGPUpdate)
	UpdatePathAttrs4ByteAs(update)
	peer := PathCreatePeer()
	p := NewPath(peer[0], update.NLRI[0], false, update.PathAttributes, time.Now(), false)
	assert.Equal(10, p.GetAsPathLen())
}

func TestPathPrependAsnToExistingSeqAttr(t *testing.T) {
	assert := assert.New(t)
	origin := bgp.NewPathAttributeOrigin(0)
	aspathParam := []bgp.AsPathParamInterface{
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint16{65001, 65002, 65003, 65004, 65005}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_SET, []uint16{65001, 65002, 65003, 65004, 65005}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ, []uint16{65100, 65101, 65102}),
		bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET, []uint16{65100, 65101})}
	aspath := bgp.NewPathAttributeAsPath(aspathParam)
	nexthop := bgp.NewPathAttributeNextHop("192.168.50.1")

	pathAttributes := []bgp.PathAttributeInterface{
		origin,
		aspath,
		nexthop,
	}

	nlri := []*bgp.IPAddrPrefix{bgp.NewIPAddrPrefix(24, "10.10.10.0")}
	bgpmsg := bgp.NewBGPUpdateMessage(nil, pathAttributes, nlri)
	update := bgpmsg.Body.(*bgp.BGPUpdate)
	UpdatePathAttrs4ByteAs(update)
	peer := PathCreatePeer()
	p := NewPath(peer[0], update.NLRI[0], false, update.PathAttributes, time.Now(), false)

	p.PrependAsn(65000, 1)
	assert.Equal([]uint32{65000, 65001, 65002, 65003, 65004, 65005, 0, 0, 0}, p.GetAsSeqList())
	fmt.Printf("asns: %v", p.GetAsSeqList())
}

func TestTimeTieBreaker(t *testing.T) {
	origin := bgp.NewPathAttributeOrigin(0)
	aspathParam := []bgp.AsPathParamInterface{bgp.NewAs4PathParam(2, []uint32{65001})}
	aspath := bgp.NewPathAttributeAsPath(aspathParam)
	nexthop := bgp.NewPathAttributeNextHop("10.0.0.1")
	med := bgp.NewPathAttributeMultiExitDisc(0)
	pathAttributes := []bgp.PathAttributeInterface{origin, aspath, nexthop, med}
	nlri := bgp.NewIPAddrPrefix(24, "10.10.0.0")
	updateMsg := bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	peer1 := &PeerInfo{AS: 2, LocalAS: 1, Address: net.IP{1, 1, 1, 1}, ID: net.IP{1, 1, 1, 1}}
	path1 := ProcessMessage(updateMsg, peer1, time.Now())[0]

	peer2 := &PeerInfo{AS: 2, LocalAS: 1, Address: net.IP{2, 2, 2, 2}, ID: net.IP{2, 2, 2, 2}} // weaker router-id
	path2 := ProcessMessage(updateMsg, peer2, time.Now().Add(-1*time.Hour))[0]                 // older than path1

	d := NewDestination(nlri)
	d.AddNewPath(path1)
	d.AddNewPath(path2)

	d.Calculate(nil)

	assert.Equal(t, len(d.knownPathList), 2)
	assert.Equal(t, true, d.GetBestPath("").GetSource().ID.Equal(net.IP{2, 2, 2, 2})) // path from peer2 win

	// this option disables tie breaking by age
	SelectionOptions.ExternalCompareRouterId = true
	d = NewDestination(nlri)
	d.AddNewPath(path1)
	d.AddNewPath(path2)

	d.Calculate(nil)

	assert.Equal(t, len(d.knownPathList), 2)
	assert.Equal(t, true, d.GetBestPath("").GetSource().ID.Equal(net.IP{1, 1, 1, 1})) // path from peer1 win
}

//AddLocalProtoRoute is used to add local endpoint to the protocol RIB
func (self *OfnetBgp) AddLocalProtoRoute(pathInfo []*OfnetProtoRouteInfo) error {

	if self.routerIP == "" {
		//ignoring populating to the bgp rib because
		//Bgp is not configured.
		return nil
	}
	log.Infof("Received AddLocalProtoRoute to add local endpoint to protocol RIB: %+v", pathInfo)

	// add routes
	attrs := []bgp.PathAttributeInterface{
		bgp.NewPathAttributeOrigin(1),
		bgp.NewPathAttributeNextHop(pathInfo[0].nextHopIP),
		bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, []uint32{self.myBgpAs})}),
	}
	paths := []*table.Path{}
	for _, path := range pathInfo {
		paths = append(paths, table.NewPath(nil, bgp.NewIPAddrPrefix(32, path.localEpIP), false, attrs, time.Now(), false))
	}

	_, err := self.bgpServer.AddPath("", paths)
	if err != nil {
		return err
	}

	return nil
}

// before:
//  as-path  : 65000, 4000, 23456, 23456, 40001
//  as4-path : {10, 20, 30} 400000, 300000, 40001
// expected result:
//  as-path  : 65000, {10, 20, 30}, 400000, 300000, 40001
func TestAsPathAs4Trans5(t *testing.T) {
	as := []uint16{65000, 4000, bgp.AS_TRANS, bgp.AS_TRANS, 40001}
	params := []bgp.AsPathParamInterface{bgp.NewAsPathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, as)}
	aspath := bgp.NewPathAttributeAsPath(params)

	as4 := []uint32{400000, 300000, 40001}
	as4param1 := bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, as4)
	as5 := []uint32{10, 20, 30}
	as4param2 := bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SET, as5)
	param4s := []*bgp.As4PathParam{as4param2, as4param1}
	as4path := bgp.NewPathAttributeAs4Path(param4s)
	msg := bgp.NewBGPUpdateMessage(nil, []bgp.PathAttributeInterface{aspath, as4path}, nil).Body.(*bgp.BGPUpdate)
	UpdatePathAttrs4ByteAs(msg)
	assert.Equal(t, len(msg.PathAttributes), 1)
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value), 3)
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.As4PathParam).AS), 1)
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.As4PathParam).AS[0], uint32(65000))
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[1].(*bgp.As4PathParam).AS), 3)
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[1].(*bgp.As4PathParam).AS[0], uint32(10))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[1].(*bgp.As4PathParam).AS[1], uint32(20))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[1].(*bgp.As4PathParam).AS[2], uint32(30))
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[2].(*bgp.As4PathParam).AS), 3)
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[2].(*bgp.As4PathParam).AS[0], uint32(400000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[2].(*bgp.As4PathParam).AS[1], uint32(300000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[2].(*bgp.As4PathParam).AS[2], uint32(40001))
}

// PrependAsn prepends AS number.
// This function updates the AS_PATH attribute as follows.
//  1) if the first path segment of the AS_PATH is of type
//     AS_SEQUENCE, the local system prepends the specified AS num as
//     the last element of the sequence (put it in the left-most
//     position with respect to the position of  octets in the
//     protocol message) the specified number of times.
//     If the act of prepending will cause an overflow in the AS_PATH
//     segment (i.e.,  more than 255 ASes),
//     it SHOULD prepend a new segment of type AS_SEQUENCE
//     and prepend its own AS number to this new segment.
//
//  2) if the first path segment of the AS_PATH is of other than type
//     AS_SEQUENCE, the local system prepends a new path segment of type
//     AS_SEQUENCE to the AS_PATH, including the specified AS number in
//     that segment.
//
//  3) if the AS_PATH is empty, the local system creates a path
//     segment of type AS_SEQUENCE, places the specified AS number
//     into that segment, and places that segment into the AS_PATH.
func (path *Path) PrependAsn(asn uint32, repeat uint8) {

	original := path.GetAsPath()

	asns := make([]uint32, repeat)
	for i, _ := range asns {
		asns[i] = asn
	}

	var asPath *bgp.PathAttributeAsPath
	if original == nil {
		asPath = bgp.NewPathAttributeAsPath([]bgp.AsPathParamInterface{})
	} else {
		asPath = cloneAsPath(original)
	}

	if len(asPath.Value) > 0 {
		fst := asPath.Value[0].(*bgp.As4PathParam)
		if fst.Type == bgp.BGP_ASPATH_ATTR_TYPE_SEQ {
			if len(fst.AS)+int(repeat) > 255 {
				repeat = uint8(255 - len(fst.AS))
			}
			fst.AS = append(asns[:int(repeat)], fst.AS...)
			fst.Num += repeat
			asns = asns[int(repeat):]
		}
	}

	if len(asns) > 0 {
		p := bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, asns)
		asPath.Value = append([]bgp.AsPathParamInterface{p}, asPath.Value...)
	}
	path.setPathAttr(asPath)
}

func cloneAsPath(asAttr *bgp.PathAttributeAsPath) *bgp.PathAttributeAsPath {
	newASparams := make([]bgp.AsPathParamInterface, len(asAttr.Value))
	for i, param := range asAttr.Value {
		asParam := param.(*bgp.As4PathParam)
		as := make([]uint32, len(asParam.AS))
		copy(as, asParam.AS)
		newASparams[i] = bgp.NewAs4PathParam(asParam.Type, as)
	}
	return bgp.NewPathAttributeAsPath(newASparams)
}

func TestCalculate2(t *testing.T) {

	origin := bgp.NewPathAttributeOrigin(0)
	aspathParam := []bgp.AsPathParamInterface{bgp.NewAs4PathParam(2, []uint32{65001})}
	aspath := bgp.NewPathAttributeAsPath(aspathParam)
	nexthop := bgp.NewPathAttributeNextHop("10.0.0.1")
	med := bgp.NewPathAttributeMultiExitDisc(0)
	pathAttributes := []bgp.PathAttributeInterface{origin, aspath, nexthop, med}
	nlri := bgp.NewIPAddrPrefix(24, "10.10.0.0")

	// peer1 sends normal update message 10.10.0.0/24
	update1 := bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	peer1 := &PeerInfo{AS: 1, Address: net.IP{1, 1, 1, 1}}
	path1 := ProcessMessage(update1, peer1, time.Now())[0]

	d := NewDestination(nlri)
	d.AddNewPath(path1)
	d.Calculate(nil)

	// suppose peer2 sends grammaatically correct but semantically flawed update message
	// which has a withdrawal nlri not advertised before
	update2 := bgp.NewBGPUpdateMessage([]*bgp.IPAddrPrefix{nlri}, pathAttributes, nil)
	peer2 := &PeerInfo{AS: 2, Address: net.IP{2, 2, 2, 2}}
	path2 := ProcessMessage(update2, peer2, time.Now())[0]
	assert.Equal(t, path2.IsWithdraw, true)

	d.AddWithdraw(path2)
	d.Calculate(nil)

	// we have a path from peer1 here
	assert.Equal(t, len(d.knownPathList), 1)

	// after that, new update with the same nlri comes from peer2
	update3 := bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	path3 := ProcessMessage(update3, peer2, time.Now())[0]
	assert.Equal(t, path3.IsWithdraw, false)

	d.AddNewPath(path3)
	d.Calculate(nil)

	// this time, we have paths from peer1 and peer2
	assert.Equal(t, len(d.knownPathList), 2)

	// now peer3 sends normal update message 10.10.0.0/24
	peer3 := &PeerInfo{AS: 3, Address: net.IP{3, 3, 3, 3}}
	update4 := bgp.NewBGPUpdateMessage(nil, pathAttributes, []*bgp.IPAddrPrefix{nlri})
	path4 := ProcessMessage(update4, peer3, time.Now())[0]

	d.AddNewPath(path4)
	d.Calculate(nil)

	// we must have paths from peer1, peer2 and peer3
	assert.Equal(t, len(d.knownPathList), 3)
}

func UpdatePathAttrs2ByteAs(msg *bgp.BGPUpdate) error {
	ps := msg.PathAttributes
	msg.PathAttributes = make([]bgp.PathAttributeInterface, len(ps))
	copy(msg.PathAttributes, ps)
	var asAttr *bgp.PathAttributeAsPath
	idx := 0
	for i, attr := range msg.PathAttributes {
		if a, ok := attr.(*bgp.PathAttributeAsPath); ok {
			asAttr = a
			idx = i
			break
		}
	}

	if asAttr == nil {
		return nil
	}

	as4Params := make([]*bgp.As4PathParam, 0, len(asAttr.Value))
	as2Params := make([]bgp.AsPathParamInterface, 0, len(asAttr.Value))
	mkAs4 := false
	for _, param := range asAttr.Value {
		as4Param := param.(*bgp.As4PathParam)
		as2Path := make([]uint16, 0, len(as4Param.AS))
		for _, as := range as4Param.AS {
			if as > (1<<16)-1 {
				mkAs4 = true
				as2Path = append(as2Path, bgp.AS_TRANS)
			} else {
				as2Path = append(as2Path, uint16(as))
			}
		}
		as2Params = append(as2Params, bgp.NewAsPathParam(as4Param.Type, as2Path))

		// RFC 6793 4.2.2 Generating Updates
		//
		// Whenever the AS path information contains the AS_CONFED_SEQUENCE or
		// AS_CONFED_SET path segment, the NEW BGP speaker MUST exclude such
		// path segments from the AS4_PATH attribute being constructed.
		if as4Param.Type != bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ && as4Param.Type != bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET {
			as4Params = append(as4Params, as4Param)
		}
	}
	msg.PathAttributes[idx] = bgp.NewPathAttributeAsPath(as2Params)
	if mkAs4 {
		msg.PathAttributes = append(msg.PathAttributes, bgp.NewPathAttributeAs4Path(as4Params))
	}
	return nil
}

// before:
//  as-path  : 65000, 4000, 40000, 30000, 40001
// expected result:
//  as-path  : 65000, 4000, 40000, 30000, 40001
func TestAsPathAs2Trans2(t *testing.T) {
	as := []uint32{65000, 4000, 40000, 30000, 40001}
	params := []bgp.AsPathParamInterface{bgp.NewAs4PathParam(bgp.BGP_ASPATH_ATTR_TYPE_SEQ, as)}
	aspath := bgp.NewPathAttributeAsPath(params)
	msg := bgp.NewBGPUpdateMessage(nil, []bgp.PathAttributeInterface{aspath}, nil).Body.(*bgp.BGPUpdate)
	UpdatePathAttrs2ByteAs(msg)
	assert.Equal(t, len(msg.PathAttributes), 1)
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value), 1)
	assert.Equal(t, len(msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS), 5)
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS[0], uint16(65000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS[1], uint16(4000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS[2], uint16(40000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS[3], uint16(30000))
	assert.Equal(t, msg.PathAttributes[0].(*bgp.PathAttributeAsPath).Value[0].(*bgp.AsPathParam).AS[4], uint16(40001))
}