Implement second exchange in IKEv1 main mode

src/libcharon/sa/tasks/main_mode.c

@@ -54,6 +54,34 @@ struct private_main_mode_t {
 	 * selected IKE proposal
 	 */
 	proposal_t *proposal;
+
+	/**
+	 * DH exchange
+	 */
+	diffie_hellman_t *dh;
+
+	/**
+	 * Received public DH value from peer
+	 */
+	chunk_t dh_value;
+
+	/**
+	 * Initiators nonce
+	 */
+	chunk_t nonce_i;
+
+	/**
+	 * Responder nonce
+	 */
+	chunk_t nonce_r;
+
+	/** states of main mode */
+	enum {
+		MM_INIT,
+		MM_SA,
+		MM_KE,
+		MM_ID,
+	} state;
 };
 
 METHOD(task_t, build_i, status_t,
@@ -66,43 +94,128 @@ METHOD(task_t, build_i, status_t,
 METHOD(task_t, process_r,  status_t,
 	private_main_mode_t *this, message_t *message)
 {
-	this->config = this->ike_sa->get_ike_cfg(this->ike_sa);
-	DBG0(DBG_IKE, "%H is initiating a Main Mode", message->get_source(message));
-	this->ike_sa->set_state(this->ike_sa, IKE_CONNECTING);
-
-	if (!this->proposal)
+	switch (this->state)
 	{
-		linked_list_t *list;
-		sa_payload_t *sa_payload;
-
-		sa_payload = (sa_payload_t*)message->get_payload(message,
-												SECURITY_ASSOCIATION_V1);
-		if (!sa_payload)
+		case MM_INIT:
 		{
-			DBG1(DBG_IKE, "SA payload missing");
-			return FAILED;
-		}
-		list = sa_payload->get_proposals(sa_payload);
-		this->proposal = this->config->select_proposal(this->config, list, FALSE);
 
-		if (!this->proposal)
-		{
-			DBG1(DBG_IKE, "no proposal found");
-			return FAILED;
+			linked_list_t *list;
+			sa_payload_t *sa_payload;
+
+			this->config = this->ike_sa->get_ike_cfg(this->ike_sa);
+			DBG0(DBG_IKE, "%H is initiating a Main Mode",
+				 message->get_source(message));
+			this->ike_sa->set_state(this->ike_sa, IKE_CONNECTING);
+
+			sa_payload = (sa_payload_t*)message->get_payload(message,
+													SECURITY_ASSOCIATION_V1);
+			if (!sa_payload)
+			{
+				DBG1(DBG_IKE, "SA payload missing");
+				return FAILED;
+			}
+			list = sa_payload->get_proposals(sa_payload);
+			this->proposal = this->config->select_proposal(this->config,
+														   list, FALSE);
+			if (!this->proposal)
+			{
+				DBG1(DBG_IKE, "no proposal found");
+				return FAILED;
+			}
+			this->state = MM_SA;
+			return NEED_MORE;
 		}
+		case MM_SA:
+		{
+			ke_payload_t *ke_payload;
+			nonce_payload_t *nonce_payload;
+			u_int16_t group;
+
+			ke_payload = (ke_payload_t*)message->get_payload(message,
+															 KEY_EXCHANGE_V1);
+			if (!ke_payload)
+			{
+				DBG1(DBG_IKE, "KE payload missing");
+				return FAILED;
+			}
+			this->dh_value = ke_payload->get_key_exchange_data(ke_payload);
+			this->dh_value = chunk_clone(this->dh_value);
+
+			if (!this->proposal->get_algorithm(this->proposal,
+										DIFFIE_HELLMAN_GROUP, &group, NULL))
+			{
+				DBG1(DBG_IKE, "DH group selection failed");
+				return FAILED;
+			}
+			this->dh = lib->crypto->create_dh(lib->crypto, group);
+			if (!this->dh)
+			{
+				DBG1(DBG_IKE, "negotiated DH group not supported");
+				return FAILED;
+			}
+			this->dh->set_other_public_value(this->dh, this->dh_value);
+
+
+			nonce_payload = (nonce_payload_t*)message->get_payload(message,
+																   NONCE_V1);
+			if (!nonce_payload)
+			{
+				DBG1(DBG_IKE, "Nonce payload missing");
+				return FAILED;
+			}
+			this->nonce_i = nonce_payload->get_nonce(nonce_payload);
+			/* TODO-IKEv1: verify nonce length */
+
+			this->state = MM_KE;
+			return NEED_MORE;
+		}
+		default:
+			return FAILED;
 	}
-	return NEED_MORE;
 }
 
 METHOD(task_t, build_r, status_t,
 	private_main_mode_t *this, message_t *message)
 {
-	sa_payload_t *sa_payload;
+	switch (this->state)
+	{
+		case MM_SA:
+		{
+			sa_payload_t *sa_payload;
 
-	sa_payload = sa_payload_create_from_proposal(SECURITY_ASSOCIATION_V1,
-												 this->proposal);
-	message->add_payload(message, &sa_payload->payload_interface);
-	return NEED_MORE;
+			sa_payload = sa_payload_create_from_proposal(SECURITY_ASSOCIATION_V1,
+														 this->proposal);
+			message->add_payload(message, &sa_payload->payload_interface);
+			return NEED_MORE;
+		}
+		case MM_KE:
+		{
+			ke_payload_t *ke_payload;
+			nonce_payload_t *nonce_payload;
+			rng_t *rng;
+
+			ke_payload = ke_payload_create_from_diffie_hellman(KEY_EXCHANGE_V1,
+															   this->dh);
+			message->add_payload(message, &ke_payload->payload_interface);
+
+			rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK);
+			if (!rng)
+			{
+				DBG1(DBG_IKE, "no RNG found to create nonce");
+				return FAILED;
+			}
+			/* TODO-IKEv1: nonce size? */
+			rng->allocate_bytes(rng, 20, &this->nonce_r);
+			rng->destroy(rng);
+
+			nonce_payload = nonce_payload_create(NONCE_V1);
+			nonce_payload->set_nonce(nonce_payload, this->nonce_r);
+			message->add_payload(message, &nonce_payload->payload_interface);
+			return NEED_MORE;
+		}
+		default:
+			return FAILED;
+	}
 }
 
 METHOD(task_t, process_i, status_t,
@@ -128,6 +241,10 @@ METHOD(task_t, destroy, void,
 	private_main_mode_t *this)
 {
 	DESTROY_IF(this->proposal);
+	DESTROY_IF(this->dh);
+	free(this->dh_value.ptr);
+	free(this->nonce_i.ptr);
+	free(this->nonce_r.ptr);
 	free(this);
 }
 
@@ -148,6 +265,7 @@ main_mode_t *main_mode_create(ike_sa_t *ike_sa, bool initiator)
 		},
 		.ike_sa = ike_sa,
 		.initiator = initiator,
+		.state = MM_INIT,
 	);
 
 	if (initiator)