From 2393690267a84d2c19148631b32bc5e0496da26b Mon Sep 17 00:00:00 2001
From: Yoshiyuki Kurauchi <ahochauwaaaaa@gmail.com>
Date: Sat, 23 Dec 2023 15:32:25 +0100
Subject: [PATCH] Fix SMF Set ID encoding

---
 ie/ie.go                                  |  2 +-
 ie/ie_string_test.go                      |  2 +-
 ie/ie_test.go                             |  2 +-
 ie/smf-set-id.go                          | 32 ++++-------------------
 message/association-setup-request_test.go |  4 +--
 5 files changed, 10 insertions(+), 32 deletions(-)

diff --git a/ie/ie.go b/ie/ie.go
index 5b53690..02cdb83 100644
--- a/ie/ie.go
+++ b/ie/ie.go
@@ -421,7 +421,7 @@ func (i *IE) ValueAsString() (string, error) {
 	return string(i.Payload), nil
 }
 
-// ValueAsFQDN returns the value of IE as FQDN.
+// ValueAsFQDN returns the value of IE as string, decoded as FQDN.
 func (i *IE) ValueAsFQDN() (string, error) {
 	if i.IsGrouped() {
 		return "", &InvalidTypeError{Type: i.Type}
diff --git a/ie/ie_string_test.go b/ie/ie_string_test.go
index 3e6b1cc..986c89c 100644
--- a/ie/ie_string_test.go
+++ b/ie/ie_string_test.go
@@ -180,7 +180,7 @@ func TestStringIEs(t *testing.T) {
 			description: "SMFSetID",
 			structured:  ie.NewSMFSetID("go-pfcp"),
 			decoded:     "go-pfcp",
-			decoderFunc: func(i *ie.IE) (string, error) { return i.SMFSetIDString() },
+			decoderFunc: func(i *ie.IE) (string, error) { return i.SMFSetID() },
 		}, {
 			description: "UEIPAddressPoolIdentity",
 			structured:  ie.NewUEIPAddressPoolIdentity("go-pfcp"),
diff --git a/ie/ie_test.go b/ie/ie_test.go
index 444eac3..a751360 100644
--- a/ie/ie_test.go
+++ b/ie/ie_test.go
@@ -2451,7 +2451,7 @@ func TestIEs(t *testing.T) {
 		}, {
 			"SMFSetID",
 			ie.NewSMFSetID("go-pfcp.epc.3gppnetwork.org"),
-			[]byte{0x00, 0xb4, 0x00, 0x1c, 0x00, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x2e, 0x65, 0x70, 0x63, 0x2e, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x2e, 0x6f, 0x72, 0x67},
+			[]byte{0x00, 0xb4, 0x00, 0x1c, 0x07, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x03, 0x65, 0x70, 0x63, 0x0b, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x03, 0x6f, 0x72, 0x67},
 		}, {
 			"QuotaValidityTime",
 			ie.NewQuotaValidityTime(10 * time.Second),
diff --git a/ie/smf-set-id.go b/ie/smf-set-id.go
index fc93437..cfb5c9b 100644
--- a/ie/smf-set-id.go
+++ b/ie/smf-set-id.go
@@ -4,38 +4,16 @@
 
 package ie
 
-import "io"
-
 // NewSMFSetID creates a new SMFSetID IE.
 func NewSMFSetID(id string) *IE {
-	l := len([]byte(id))
-	i := New(SMFSetID, make([]byte, 1+l))
-
-	i.Payload[0] = 0 // Spare
-	copy(i.Payload[1:], id)
-
-	return i
+	return newFQDNIE(SMFSetID, id)
 }
 
-// SMFSetID returns SMFSetID in []byte if the type of IE matches.
-func (i *IE) SMFSetID() ([]byte, error) {
+// SMFSetID returns SMFSetID in string if the type of IE matches.
+func (i *IE) SMFSetID() (string, error) {
 	if i.Type != SMFSetID {
-		return nil, &InvalidTypeError{Type: i.Type}
-	}
-
-	return i.Payload, nil
-}
-
-// SMFSetIDString returns SMFSetID in string if the type of IE matches.
-func (i *IE) SMFSetIDString() (string, error) {
-	v, err := i.SMFSetID()
-	if err != nil {
-		return "", err
-	}
-
-	if len(v) < 1 {
-		return "", io.ErrUnexpectedEOF
+		return "", &InvalidTypeError{Type: i.Type}
 	}
 
-	return string(v[1:]), nil
+	return i.ValueAsFQDN()
 }
diff --git a/message/association-setup-request_test.go b/message/association-setup-request_test.go
index 5a010b6..ba5791b 100644
--- a/message/association-setup-request_test.go
+++ b/message/association-setup-request_test.go
@@ -59,7 +59,7 @@ func TestAssociationSetupRequest(t *testing.T) {
 				0x00, 0x2b, 0x00, 0x02, 0x01, 0x02,
 				0x00, 0x59, 0x00, 0x01, 0x3f,
 				0x00, 0xb2, 0x00, 0x15, 0x03, 0x7f, 0x00, 0x00, 0x01, 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
-				0x00, 0xb4, 0x00, 0x1c, 0x00, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x2e, 0x65, 0x70, 0x63, 0x2e, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x2e, 0x6f, 0x72, 0x67,
+				0x00, 0xb4, 0x00, 0x1c, 0x07, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x03, 0x65, 0x70, 0x63, 0x0b, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x03, 0x6f, 0x72, 0x67,
 				0x00, 0xb7, 0x00, 0x09,
 				0x00, 0xb9, 0x00, 0x05, 0x02, 0x7f, 0x00, 0x00, 0x01,
 				0x00, 0xe9, 0x00, 0x25,
@@ -165,7 +165,7 @@ func TestAssociationSetupRequest(t *testing.T) {
 				0x00,
 				0x00, 0xb2, 0x00, 0x15, 0x03, 0x7f, 0x00, 0x00, 0x01, 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
 				0x00, 0xb2, 0x00, 0x15, 0x03, 0x7f, 0x00, 0x00, 0x02, 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02,
-				0x00, 0xb4, 0x00, 0x1c, 0x00, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x2e, 0x65, 0x70, 0x63, 0x2e, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x2e, 0x6f, 0x72, 0x67,
+				0x00, 0xb4, 0x00, 0x1c, 0x07, 0x67, 0x6f, 0x2d, 0x70, 0x66, 0x63, 0x70, 0x03, 0x65, 0x70, 0x63, 0x0b, 0x33, 0x67, 0x70, 0x70, 0x6e, 0x65, 0x74, 0x77, 0x6f, 0x72, 0x6b, 0x03, 0x6f, 0x72, 0x67,
 				0x00, 0xb7, 0x00, 0x09,
 				0x00, 0xb9, 0x00, 0x05, 0x02, 0x7f, 0x00, 0x00, 0x01,
 				0x00, 0xe9, 0x00, 0x29,