pkg/packet/bgp: fix ParsePmsiTunnel() and NewPathAttributePmsiTunnel() crash

Once we create an object, we should not mutate it. This fixes the
following in a different way.

https://github.com/osrg/gobgp/pull/1778

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

1 files changed, 13 insertions, 10 deletions

diff --git a/pkg/packet/bgp/bgp.go b/pkg/packet/bgp/bgp.go
index 01251167..1be42ec5 100644
--- a/pkg/packet/bgp/bgp.go
+++ b/pkg/packet/bgp/bgp.go
@@ -8443,6 +8443,9 @@ func (p *PathAttributePmsiTunnel) MarshalJSON() ([]byte, error) {
 }
 
 func NewPathAttributePmsiTunnel(typ PmsiTunnelType, isLeafInfoRequired bool, label uint32, id PmsiTunnelIDInterface) *PathAttributePmsiTunnel {
+	if id == nil {
+		return nil
+	}
 	// Flags(1) + TunnelType(1) + Label(3) + TunnelID(variable)
 	l := 5 + id.Len()
 	t := BGP_ATTR_TYPE_PMSI_TUNNEL
@@ -8466,22 +8469,22 @@ func ParsePmsiTunnel(args []string) (*PathAttributePmsiTunnel, error) {
 		return nil, fmt.Errorf("invalid pmsi tunnel arguments: %s", args)
 	}
 
-	pmsi := NewPathAttributePmsiTunnel(0, false, 0, nil)
-
+	var tunnelType PmsiTunnelType
+	var isLeafInfoRequired bool
 	switch args[0] {
 	case "ingress-repl":
-		pmsi.TunnelType = PMSI_TUNNEL_TYPE_INGRESS_REPL
+		tunnelType = PMSI_TUNNEL_TYPE_INGRESS_REPL
 	default:
 		typ, err := strconv.ParseUint(args[0], 10, 8)
 		if err != nil {
 			return nil, fmt.Errorf("invalid pmsi tunnel type: %s", args[0])
 		}
-		pmsi.TunnelType = PmsiTunnelType(typ)
+		tunnelType = PmsiTunnelType(typ)
 	}
 
 	indx := 1
 	if args[indx] == "leaf-info-required" {
-		pmsi.IsLeafInfoRequired = true
+		isLeafInfoRequired = true
 		indx++
 	}
 
@@ -8489,21 +8492,21 @@ func ParsePmsiTunnel(args []string) (*PathAttributePmsiTunnel, error) {
 	if err != nil {
 		return nil, fmt.Errorf("invalid pmsi tunnel label: %s", args[indx])
 	}
-	pmsi.Label = uint32(label)
 	indx++
 
-	switch pmsi.TunnelType {
+	var id PmsiTunnelIDInterface
+	switch tunnelType {
 	case PMSI_TUNNEL_TYPE_INGRESS_REPL:
 		ip := net.ParseIP(args[indx])
 		if ip == nil {
 			return nil, fmt.Errorf("invalid pmsi tunnel identifier: %s", args[indx])
 		}
-		pmsi.TunnelID = &IngressReplTunnelID{Value: ip}
+		id = &IngressReplTunnelID{Value: ip}
 	default:
-		pmsi.TunnelID = &DefaultPmsiTunnelID{Value: []byte(args[indx])}
+		id = &DefaultPmsiTunnelID{Value: []byte(args[indx])}
 	}
 
-	return pmsi, nil
+	return NewPathAttributePmsiTunnel(tunnelType, isLeafInfoRequired, uint32(label), id), nil
 }
 
 type PathAttributeIP6ExtendedCommunities struct {