2 files changed, 40 insertions, 27 deletions

diff --git a/packet/bgp.go b/packet/bgp.go
index c910f310..d1c77303 100644
--- a/packet/bgp.go
+++ b/packet/bgp.go
@@ -2703,6 +2703,9 @@ type PathAttribute struct {
 }
 
 func (p *PathAttribute) Len() int {
+	if p.Length == 0 {
+		p.Length = uint16(len(p.Value))
+	}
 	l := 2 + p.Length
 	if p.Flags&BGP_ATTR_FLAG_EXTENDED_LENGTH != 0 {
 		l += 2
diff --git a/table/message.go b/table/message.go
index b7edc383..212cf2c1 100644
--- a/table/message.go
+++ b/table/message.go
@@ -16,8 +16,8 @@
 package table
 
 import (
-	"bytes"
 	"github.com/osrg/gobgp/packet"
+	"reflect"
 )
 
 func UpdatePathAttrs2ByteAs(msg *bgp.BGPUpdate) error {
@@ -183,47 +183,57 @@ func createUpdateMsgFromPath(path *Path, msg *bgp.BGPMessage) *bgp.BGPMessage {
 	return nil
 }
 
-func isSamePathAttrs(pList1 []bgp.PathAttributeInterface, pList2 []bgp.PathAttributeInterface) bool {
-	if len(pList1) != len(pList2) {
+func isMergeable(p1, p2 *Path, msg *bgp.BGPMessage) bool {
+	if p1 == nil {
 		return false
 	}
-	for i, p1 := range pList1 {
-		_, y := p1.(*bgp.PathAttributeMpReachNLRI)
-		if y {
-			continue
-		}
-		b1, _ := p1.Serialize()
-		b2, _ := pList2[i].Serialize()
-
-		if bytes.Compare(b1, b2) != 0 {
-			return false
-		}
+	if p1.GetRouteFamily() != bgp.RF_IPv4_UC || p2.GetRouteFamily() != bgp.RF_IPv4_UC {
+		return false
 	}
-	return true
-}
-
-func isMergeable(p1, p2 *Path) bool {
-	return false
-	if p1 == nil {
+	if p1.IsWithdraw || p2.IsWithdraw {
 		return false
 	}
-	if p1.GetRouteFamily() != bgp.RF_IPv4_UC {
+	if p1.GetSource().Address.Equal(p2.GetSource().Address) == false {
 		return false
 	}
-	if p1.GetSource().Equal(p2.GetSource()) && isSamePathAttrs(p1.GetPathAttrs(), p2.GetPathAttrs()) {
-		return true
+	if reflect.DeepEqual(p1.GetPathAttrs(), p2.GetPathAttrs()) == false {
+		return false
+	}
+
+	u := msg.Body.(*bgp.BGPUpdate)
+	// arbitrary number. just avoid too many NLRIs in one message.
+	if len(u.NLRI) > 16 {
+		return false
+	}
+
+	msgLen := func(u *bgp.BGPUpdate) int {
+		attrsLen := 0
+		for _, a := range u.PathAttributes {
+			attrsLen += a.Len()
+		}
+		// Header + Update (WithdrawnRoutesLen +
+		// TotalPathAttributeLen + attributes + maxlen of
+		// NLRI). Note that we try to add one NLRI.
+		return 19 + 2 + 2 + attrsLen + (len(u.NLRI)+1)*5
+	}(u)
+
+	// 128 is arbitrary number. just avoid too tight.
+	if msgLen+128 > bgp.BGP_MAX_MESSAGE_LENGTH {
+		return false
 	}
-	return false
+	return true
 }
 
 func CreateUpdateMsgFromPaths(pathList []*Path) []*bgp.BGPMessage {
 	var pre *Path
 	var msgs []*bgp.BGPMessage
 	for _, path := range pathList {
-		y := isMergeable(pre, path)
+		y := false
+		if pre != nil {
+			y = isMergeable(pre, path, msgs[len(msgs)-1])
+		}
 		if y {
-			msg := msgs[len(msgs)-1]
-			createUpdateMsgFromPath(path, msg)
+			createUpdateMsgFromPath(path, msgs[len(msgs)-1])
 		} else {
 			msg := createUpdateMsgFromPath(path, nil)
 			pre = path