Raise an alert if IKE proposals mismatch

src/libcharon/bus/bus.h

@@ -107,6 +107,8 @@ enum alert_t {
 	ALERT_RETRANSMIT_SEND_TIMEOUT,
 	/** received a retransmit for a message, argument is message_t */
 	ALERT_RETRANSMIT_RECEIVE,
+	/** IKE proposals do not match, argument is linked_list_t of proposal_t */
+	ALERT_PROPOSAL_MISMATCH_IKE,
 };
 
 /**

src/libcharon/sa/ikev2/tasks/ike_init.c

@@ -187,6 +187,11 @@ static void process_payloads(private_ike_init_t *this, message_t *message)
 														   EXT_STRONGSWAN);
 				this->proposal = this->config->select_proposal(this->config,
 														proposal_list, private);
+				if (!this->proposal)
+				{
+					charon->bus->alert(charon->bus, ALERT_PROPOSAL_MISMATCH_IKE,
+									   proposal_list);
+				}
 				proposal_list->destroy_offset(proposal_list,
 											  offsetof(proposal_t, destroy));
 				break;