From d4d97da22058ef2e1a4e41474fc80384014402e2 Mon Sep 17 00:00:00 2001
From: FUJITA Tomonori <fujita.tomonori@gmail.com>
Date: Sat, 1 Jul 2023 13:35:40 +0900
Subject: [PATCH] pkg/packet/mrt: restore compatibility

restore the API breakage due to c801e18495e36e48a4.

However, this is a hack. Should be removed with the major version updated.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
 pkg/packet/mrt/mrt.go      | 27 +++++++++++++++++++++++----
 pkg/packet/mrt/mrt_test.go |  8 ++++----
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/pkg/packet/mrt/mrt.go b/pkg/packet/mrt/mrt.go
index cad57709..cdb0c9c9 100644
--- a/pkg/packet/mrt/mrt.go
+++ b/pkg/packet/mrt/mrt.go
@@ -365,7 +365,7 @@ type RibEntry struct {
 
 var errNotAllRibEntryBytesAvailable = errors.New("not all RibEntry bytes are available")
 
-func (e *RibEntry) DecodeFromBytes(data []byte, prefix bgp.AddrPrefixInterface) ([]byte, error) {
+func (e *RibEntry) DecodeFromBytes(data []byte, prefix ...bgp.AddrPrefixInterface) ([]byte, error) {
 	if len(data) < 8 {
 		return nil, errNotAllRibEntryBytesAvailable
 	}
@@ -384,7 +384,16 @@ func (e *RibEntry) DecodeFromBytes(data []byte, prefix bgp.AddrPrefixInterface)
 		if err != nil {
 			return nil, err
 		}
-		err = p.DecodeFromBytes(data, &bgp.MarshallingOption{ImplicitPrefix: prefix})
+
+		// HACK: keeps compatibility
+		switch len(prefix) {
+		case 0:
+			err = p.DecodeFromBytes(data)
+		case 1:
+			err = p.DecodeFromBytes(data, &bgp.MarshallingOption{ImplicitPrefix: prefix[0]})
+		default:
+			return nil, fmt.Errorf("only one prefix should be used")
+		}
 		if err != nil {
 			return nil, err
 		}
@@ -398,11 +407,21 @@ func (e *RibEntry) DecodeFromBytes(data []byte, prefix bgp.AddrPrefixInterface)
 	return data, nil
 }
 
-func (e *RibEntry) Serialize(prefix bgp.AddrPrefixInterface) ([]byte, error) {
+func (e *RibEntry) Serialize(prefix ...bgp.AddrPrefixInterface) ([]byte, error) {
 	pbuf := make([]byte, 0)
 	totalLen := 0
 	for _, pattr := range e.PathAttributes {
-		pb, err := pattr.Serialize(&bgp.MarshallingOption{ImplicitPrefix: prefix})
+		var pb []byte
+		var err error
+		// HACK: keeps compatibility
+		switch len(prefix) {
+		case 0:
+			pb, err = pattr.Serialize()
+		case 1:
+			pb, err = pattr.Serialize(&bgp.MarshallingOption{ImplicitPrefix: prefix[0]})
+		default:
+			return nil, fmt.Errorf("only one prefix should be used")
+		}
 		if err != nil {
 			return nil, err
 		}
diff --git a/pkg/packet/mrt/mrt_test.go b/pkg/packet/mrt/mrt_test.go
index 2020ecfb..275b094e 100644
--- a/pkg/packet/mrt/mrt_test.go
+++ b/pkg/packet/mrt/mrt_test.go
@@ -116,13 +116,13 @@ func TestMrtRibEntry(t *testing.T) {
 	}
 
 	e1 := NewRibEntry(1, uint32(time.Now().Unix()), 0, p, false)
-	b1, err := e1.Serialize(nil)
+	b1, err := e1.Serialize()
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	e2 := &RibEntry{}
-	rest, err := e2.DecodeFromBytes(b1, nil)
+	rest, err := e2.DecodeFromBytes(b1)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -145,13 +145,13 @@ func TestMrtRibEntryWithAddPath(t *testing.T) {
 		bgp.NewPathAttributeLocalPref(1 << 22),
 	}
 	e1 := NewRibEntry(1, uint32(time.Now().Unix()), 200, p, true)
-	b1, err := e1.Serialize(nil)
+	b1, err := e1.Serialize()
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	e2 := &RibEntry{isAddPath: true}
-	rest, err := e2.DecodeFromBytes(b1, nil)
+	rest, err := e2.DecodeFromBytes(b1)
 	if err != nil {
 		t.Fatal(err)
 	}