notify-payload: Add methods to simplify encoding and retrieving IKE SPIs

The get_spi_data() method is currently not used, so that has been
simplified so it can be used for any protocol type and any SPI length.
Same for set_spi_data(), which is currently used for IKEv1 to encode
two SPIs.

src/libcharon/encoding/payloads/notify_payload.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2018 Tobias Brunner
+ * Copyright (C) 2006-2023 Tobias Brunner
  * Copyright (C) 2005-2010 Martin Willi
  * Copyright (C) 2006 Daniel Roethlisberger
  * Copyright (C) 2005 Jan Hutter
@@ -636,6 +636,21 @@ METHOD(notify_payload_t, set_notify_type, void,
 	this->notify_type = notify_type;
 }
 
+METHOD(notify_payload_t, get_spi_data, chunk_t,
+	private_notify_payload_t *this)
+{
+	return this->spi;
+}
+
+METHOD(notify_payload_t, set_spi_data, void,
+	private_notify_payload_t *this, chunk_t spi)
+{
+	chunk_free(&this->spi);
+	this->spi = chunk_clone(spi);
+	this->spi_size = this->spi.len;
+	compute_length(this);
+}
+
 METHOD(notify_payload_t, get_spi, uint32_t,
 	private_notify_payload_t *this)
 {
@@ -656,50 +671,35 @@ METHOD(notify_payload_t, get_spi, uint32_t,
 METHOD(notify_payload_t, set_spi, void,
 	private_notify_payload_t *this, uint32_t spi)
 {
-	chunk_free(&this->spi);
 	switch (this->protocol_id)
 	{
 		case PROTO_AH:
 		case PROTO_ESP:
-			this->spi = chunk_alloc(4);
-			*((uint32_t*)this->spi.ptr) = spi;
+			set_spi_data(this, chunk_from_thing(spi));
 			break;
 		default:
 			break;
 	}
-	this->spi_size = this->spi.len;
-	compute_length(this);
 }
 
-METHOD(notify_payload_t, get_spi_data, chunk_t,
+METHOD(notify_payload_t, get_ike_spi, uint64_t,
 	private_notify_payload_t *this)
 {
-	switch (this->protocol_id)
+	if (this->protocol_id == PROTO_IKE &&
+		this->spi.len == 8)
 	{
-		case PROTO_IKE:
-			if (this->spi.len == 16)
-			{
-				return this->spi;
-			}
-		default:
-			break;
+		return *((uint64_t*)this->spi.ptr);
 	}
-	return chunk_empty;
+	return 0;
 }
 
-METHOD(notify_payload_t, set_spi_data, void,
-	private_notify_payload_t *this, chunk_t spi)
+METHOD(notify_payload_t, set_ike_spi, void,
+	private_notify_payload_t *this, uint64_t spi)
 {
-	chunk_free(&this->spi);
-	switch (this->protocol_id)
+	if (this->protocol_id == PROTO_IKE)
 	{
-		case PROTO_IKE:
-			this->spi = chunk_clone(spi);
-		default:
-			break;
+		set_spi_data(this, chunk_from_thing(spi));
 	}
-	this->spi_size = this->spi.len;
-	compute_length(this);
 }
 
 METHOD(notify_payload_t, get_notification_data, chunk_t,
@@ -749,6 +749,8 @@ notify_payload_t *notify_payload_create(payload_type_t type)
 			.set_notify_type = _set_notify_type,
 			.get_spi = _get_spi,
 			.set_spi = _set_spi,
+			.get_ike_spi = _get_ike_spi,
+			.set_ike_spi = _set_ike_spi,
 			.get_spi_data = _get_spi_data,
 			.set_spi_data = _set_spi_data,
 			.get_notification_data = _get_notification_data,

src/libcharon/encoding/payloads/notify_payload.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2018 Tobias Brunner
+ * Copyright (C) 2006-2023 Tobias Brunner
  * Copyright (C) 2006 Daniel Roethlisberger
  * Copyright (C) 2005-2006 Martin Willi
  * Copyright (C) 2005 Jan Hutter
@@ -231,43 +231,60 @@ struct notify_payload_t {
 	void (*set_notify_type) (notify_payload_t *this, notify_type_t type);
 
 	/**
-	 * Returns the currently set spi of this payload.
+	 * Returns the currently set 32-bit SPI of this payload.
 	 *
-	 * This is only valid for notifys with protocol AH|ESP
+	 * This is only valid for notify payloads with protocol AH|ESP.
 	 *
 	 * @return		SPI value
 	 */
 	uint32_t (*get_spi) (notify_payload_t *this);
 
 	/**
-	 * Sets the spi of this payload.
+	 * Sets the 32-bit SPI of this payload.
 	 *
-	 * This is only valid for notifys with protocol AH|ESP
+	 * This is only valid for notify payloads with protocol AH|ESP.
 	 *
 	 * @param spi	SPI value
 	 */
 	void (*set_spi) (notify_payload_t *this, uint32_t spi);
 
 	/**
-	 * Returns the currently set spi of this payload.
+	 * Returns the currently set 64-bit SPI of this payload.
 	 *
-	 * This is only valid for notifys with protocol ISAKMP
+	 * This is only valid for notify payloads with protocol IKE.
 	 *
 	 * @return		SPI value
 	 */
-	chunk_t (*get_spi_data) (notify_payload_t *this);
+	uint64_t (*get_ike_spi)(notify_payload_t *this);
 
 	/**
-	 * Sets the spi of this payload.
+	 * Sets the 64-bit SPI of this payload.
 	 *
-	 * This is only valid for notifys with protocol ISAKMP
+	 * This is only valid for notify payloads with protocol IKE.
 	 *
 	 * @param spi	SPI value
 	 */
-	void (*set_spi_data) (notify_payload_t *this, chunk_t spi);
+	void (*set_ike_spi)(notify_payload_t *this, uint64_t spi);
 
 	/**
-	 * Returns the currently set notification data of payload.
+	 * Returns the data encoded as SPI in this payload.
+	 *
+	 * @return		encoded SPI value
+	 */
+	chunk_t (*get_spi_data)(notify_payload_t *this);
+
+	/**
+	 * Sets the data encoded as SPI in this payload.
+	 *
+	 * This is allowed for any protocol type, but is primarily used for ISAKMP,
+	 * where notify payloads contain both SPIs.
+	 *
+	 * @param spi	SPI value (cloned)
+	 */
+	void (*set_spi_data)(notify_payload_t *this, chunk_t spi);
+
+	/**
+	 * Returns the currently set notification data of this payload.
 	 *
 	 * Returned data are not copied.
 	 *