Add a payload.get_header_length() method, remove header length definitions

src/libcharon/encoding/payloads/unknown_payload.c

@@ -102,10 +102,6 @@ static encoding_rule_t encodings[] = {
 METHOD(payload_t, verify, status_t,
 	private_unknown_payload_t *this)
 {
-	if (this->payload_length != UNKNOWN_PAYLOAD_HEADER_LENGTH + this->data.len)
-	{
-		return FAILED;
-	}
 	return SUCCESS;
 }
 
@@ -116,6 +112,12 @@ METHOD(payload_t, get_encoding_rules, int,
 	return countof(encodings);
 }
 
+METHOD(payload_t, get_header_length, int,
+	private_unknown_payload_t *this)
+{
+	return 4;
+}
+
 METHOD(payload_t, get_payload_type, payload_type_t,
 	private_unknown_payload_t *this)
 {
@@ -171,6 +173,7 @@ unknown_payload_t *unknown_payload_create(payload_type_t type)
 			.payload_interface = {
 				.verify = _verify,
 				.get_encoding_rules = _get_encoding_rules,
+				.get_header_length = _get_header_length,
 				.get_length = _get_length,
 				.get_next_type = _get_next_type,
 				.set_next_type = _set_next_type,
@@ -182,7 +185,7 @@ unknown_payload_t *unknown_payload_create(payload_type_t type)
 			.destroy = _destroy,
 		},
 		.next_payload = NO_PAYLOAD,
-		.payload_length = UNKNOWN_PAYLOAD_HEADER_LENGTH,
+		.payload_length = get_header_length(this),
 		.type = type,
 	);
 
@@ -201,7 +204,7 @@ unknown_payload_t *unknown_payload_create_data(payload_type_t type,
 	this = (private_unknown_payload_t*)unknown_payload_create(type);
 	this->data = data;
 	this->critical = critical;
-	this->payload_length = UNKNOWN_PAYLOAD_HEADER_LENGTH + data.len;
+	this->payload_length = get_header_length(this) + data.len;
 
 	return &this->public;
 }