Add an option to en-/disable IKE fragmentation

Fragments are always accepted but will not be sent if disabled.  The
vendor ID is only sent if the option is enabled.

src/libcharon/sa/ikev1/task_manager_v1.c

@@ -225,6 +225,11 @@ struct private_task_manager_t {
 
 	} frag;
 
+	/**
+	 * TRUE if fragmentation (as sender) is enabled in config
+	 */
+	bool fragmentation;
+
 	/**
 	 * List of queued tasks not yet in action
 	 */
@@ -411,7 +416,7 @@ static bool send_packet(private_task_manager_t *this, bool request,
 
 	data = packet->get_data(packet);
 	if (this->ike_sa->supports_extension(this->ike_sa, EXT_IKE_FRAGMENTATION) &&
-		data.len > MAX_FRAGMENT_SIZE)
+		this->fragmentation && data.len > MAX_FRAGMENT_SIZE)
 	{
 		fragment_payload_t *fragment;
 		u_int8_t num, count;
@@ -1996,6 +2001,8 @@ task_manager_v1_t *task_manager_v1_create(ike_sa_t *ike_sa)
 					"%s.retransmit_timeout", RETRANSMIT_TIMEOUT, charon->name),
 		.retransmit_base = lib->settings->get_double(lib->settings,
 					"%s.retransmit_base", RETRANSMIT_BASE, charon->name),
+		.fragmentation = lib->settings->get_bool(lib->settings,
+					"%s.ike_fragmentation", FALSE, charon->name),
 	);
 
 	if (!this->rng)