packet/bgp: Getter functions for AS segment

This patch adds getter functions for the segment type and AS list of
each segment without using type assertion.

Signed-off-by: IWASE Yusuke <iwase.yusuke0@gmail.com>

1 files changed, 44 insertions, 41 deletions

diff --git a/table/path.go b/table/path.go
index a04e0d66..de60e615 100644
--- a/table/path.go
+++ b/table/path.go
@@ -196,10 +196,10 @@ func (path *Path) IsEOR() bool {
 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)
+		asList := param.GetAS()
+		as := make([]uint32, len(asList))
+		copy(as, asList)
+		newASparams[i] = bgp.NewAs4PathParam(param.GetType(), as)
 	}
 	return bgp.NewPathAttributeAsPath(newASparams)
 }
@@ -439,11 +439,11 @@ func (path *Path) GetSourceAs() uint32 {
 		if len(asPathParam) == 0 {
 			return 0
 		}
-		asPath := asPathParam[len(asPathParam)-1].(*bgp.As4PathParam)
-		if asPath.Num == 0 {
+		asList := asPathParam[len(asPathParam)-1].GetAS()
+		if len(asList) == 0 {
 			return 0
 		}
-		return asPath.AS[asPath.Num-1]
+		return asList[len(asList)-1]
 	}
 	return 0
 }
@@ -631,14 +631,15 @@ func (path *Path) GetAsPathLen() int {
 func (path *Path) GetAsString() string {
 	s := bytes.NewBuffer(make([]byte, 0, 64))
 	if aspath := path.GetAsPath(); aspath != nil {
-		for i, paramIf := range aspath.Value {
-			segment := paramIf.(*bgp.As4PathParam)
+		for i, param := range aspath.Value {
+			segType := param.GetType()
+			asList := param.GetAS()
 			if i != 0 {
 				s.WriteString(" ")
 			}
 
 			sep := " "
-			switch segment.Type {
+			switch segType {
 			case bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ:
 				s.WriteString("(")
 			case bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET:
@@ -648,13 +649,13 @@ func (path *Path) GetAsString() string {
 				s.WriteString("{")
 				sep = ","
 			}
-			for j, as := range segment.AS {
+			for j, as := range asList {
 				s.WriteString(fmt.Sprintf("%d", as))
-				if j != len(segment.AS)-1 {
+				if j != len(asList)-1 {
 					s.WriteString(sep)
 				}
 			}
-			switch segment.Type {
+			switch segType {
 			case bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SEQ:
 				s.WriteString(")")
 			case bgp.BGP_ASPATH_ATTR_TYPE_CONFED_SET:
@@ -668,26 +669,26 @@ func (path *Path) GetAsString() string {
 }
 
 func (path *Path) GetAsList() []uint32 {
-	return path.getAsListofSpecificType(true, true)
+	return path.getAsListOfSpecificType(true, true)
 
 }
 
 func (path *Path) GetAsSeqList() []uint32 {
-	return path.getAsListofSpecificType(true, false)
+	return path.getAsListOfSpecificType(true, false)
 
 }
 
-func (path *Path) getAsListofSpecificType(getAsSeq, getAsSet bool) []uint32 {
+func (path *Path) getAsListOfSpecificType(getAsSeq, getAsSet bool) []uint32 {
 	asList := []uint32{}
 	if aspath := path.GetAsPath(); aspath != nil {
-		for _, paramIf := range aspath.Value {
-			segment := paramIf.(*bgp.As4PathParam)
-			if getAsSeq && segment.Type == bgp.BGP_ASPATH_ATTR_TYPE_SEQ {
-				asList = append(asList, segment.AS...)
+		for _, param := range aspath.Value {
+			segType := param.GetType()
+			if getAsSeq && segType == bgp.BGP_ASPATH_ATTR_TYPE_SEQ {
+				asList = append(asList, param.GetAS()...)
 				continue
 			}
-			if getAsSet && segment.Type == bgp.BGP_ASPATH_ATTR_TYPE_SET {
-				asList = append(asList, segment.AS...)
+			if getAsSet && segType == bgp.BGP_ASPATH_ATTR_TYPE_SET {
+				asList = append(asList, param.GetAS()...)
 			} else {
 				asList = append(asList, 0)
 			}
@@ -757,7 +758,7 @@ func (path *Path) PrependAsn(asn uint32, repeat uint8, confed bool) {
 	original := path.GetAsPath()
 
 	asns := make([]uint32, repeat)
-	for i, _ := range asns {
+	for i := range asns {
 		asns[i] = asn
 	}
 
@@ -769,13 +770,14 @@ func (path *Path) PrependAsn(asn uint32, repeat uint8, confed bool) {
 	}
 
 	if len(asPath.Value) > 0 {
-		fst := asPath.Value[0].(*bgp.As4PathParam)
-		if fst.Type == segType {
-			if len(fst.AS)+int(repeat) > 255 {
-				repeat = uint8(255 - len(fst.AS))
+		param := asPath.Value[0]
+		asList := param.GetAS()
+		if param.GetType() == segType {
+			if int(repeat)+len(asList) > 255 {
+				repeat = uint8(255 - len(asList))
 			}
-			fst.AS = append(asns[:int(repeat)], fst.AS...)
-			fst.Num += repeat
+			newAsList := append(asns[:int(repeat)], asList...)
+			asPath.Value[0] = bgp.NewAs4PathParam(segType, newAsList)
 			asns = asns[int(repeat):]
 		}
 	}
@@ -800,9 +802,9 @@ func (path *Path) RemovePrivateAS(localAS uint32, option config.RemovePrivateAsO
 	case config.REMOVE_PRIVATE_AS_OPTION_ALL, config.REMOVE_PRIVATE_AS_OPTION_REPLACE:
 		newASParams := make([]bgp.AsPathParamInterface, 0, len(original.Value))
 		for _, param := range original.Value {
-			asParam := param.(*bgp.As4PathParam)
-			newASParam := make([]uint32, 0, len(asParam.AS))
-			for _, as := range asParam.AS {
+			asList := param.GetAS()
+			newASParam := make([]uint32, 0, len(asList))
+			for _, as := range asList {
 				if isPrivateAS(as) {
 					if option == config.REMOVE_PRIVATE_AS_OPTION_REPLACE {
 						newASParam = append(newASParam, localAS)
@@ -812,7 +814,7 @@ func (path *Path) RemovePrivateAS(localAS uint32, option config.RemovePrivateAsO
 				}
 			}
 			if len(newASParam) > 0 {
-				newASParams = append(newASParams, bgp.NewAs4PathParam(asParam.Type, newASParam))
+				newASParams = append(newASParams, bgp.NewAs4PathParam(param.GetType(), newASParam))
 			}
 		}
 		path.setPathAttr(bgp.NewPathAttributeAsPath(newASParams))
@@ -826,10 +828,10 @@ func (path *Path) removeConfedAs() {
 		return
 	}
 	newAsParams := make([]bgp.AsPathParamInterface, 0, len(original.Value))
-	for _, v := range original.Value {
-		p := v.(*bgp.As4PathParam)
-		if p.Type == bgp.BGP_ASPATH_ATTR_TYPE_SEQ || p.Type == bgp.BGP_ASPATH_ATTR_TYPE_SET {
-			newAsParams = append(newAsParams, p)
+	for _, param := range original.Value {
+		switch param.GetType() {
+		case bgp.BGP_ASPATH_ATTR_TYPE_SEQ, bgp.BGP_ASPATH_ATTR_TYPE_SET:
+			newAsParams = append(newAsParams, param)
 		}
 	}
 	path.setPathAttr(bgp.NewPathAttributeAsPath(newAsParams))
@@ -843,16 +845,17 @@ func (path *Path) ReplaceAS(localAS, peerAS uint32) *Path {
 	newASParams := make([]bgp.AsPathParamInterface, 0, len(original.Value))
 	changed := false
 	for _, param := range original.Value {
-		asParam := param.(*bgp.As4PathParam)
-		newASParam := make([]uint32, 0, len(asParam.AS))
-		for _, as := range asParam.AS {
+		segType := param.GetType()
+		asList := param.GetAS()
+		newASParam := make([]uint32, 0, len(asList))
+		for _, as := range asList {
 			if as == peerAS {
 				as = localAS
 				changed = true
 			}
 			newASParam = append(newASParam, as)
 		}
-		newASParams = append(newASParams, bgp.NewAs4PathParam(asParam.Type, newASParam))
+		newASParams = append(newASParams, bgp.NewAs4PathParam(segType, newASParam))
 	}
 	if changed {
 		path = path.Clone(path.IsWithdraw)