DPP: Authentication exchange retries and channel iteration in hostapd

This extends hostapd with previoiusly implemented wpa_supplicant
functionality to retry DPP Authentication Request/Response and to
iterate over possible negotiation channels.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

src/ap/ap_drv_ops.h

@@ -103,6 +103,14 @@ int hostapd_drv_send_action_addr3_ap(struct hostapd_data *hapd,
 				     unsigned int freq,
 				     unsigned int wait, const u8 *dst,
 				     const u8 *data, size_t len);
+static inline void
+hostapd_drv_send_action_cancel_wait(struct hostapd_data *hapd)
+{
+	if (!hapd->driver || !hapd->driver->send_action_cancel_wait ||
+	    !hapd->drv_priv)
+		return;
+	hapd->driver->send_action_cancel_wait(hapd->drv_priv);
+}
 int hostapd_add_sta_node(struct hostapd_data *hapd, const u8 *addr,
 			 u16 auth_alg);
 int hostapd_sta_auth(struct hostapd_data *hapd, const u8 *addr,

src/ap/dpp_hostapd.c

@@ -20,7 +20,10 @@
 #include "dpp_hostapd.h"
 
 
+static void hostapd_dpp_reply_wait_timeout(void *eloop_ctx, void *timeout_ctx);
 static void hostapd_dpp_auth_success(struct hostapd_data *hapd, int initiator);
+static void hostapd_dpp_init_timeout(void *eloop_ctx, void *timeout_ctx);
+static int hostapd_dpp_auth_init_next(struct hostapd_data *hapd);
 
 static const u8 broadcast[ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
@@ -278,9 +281,68 @@ int hostapd_dpp_bootstrap_info(struct hostapd_data *hapd, int id,
 }
 
 
+static void hostapd_dpp_auth_resp_retry_timeout(void *eloop_ctx,
+						void *timeout_ctx)
+{
+	struct hostapd_data *hapd = eloop_ctx;
+	struct dpp_authentication *auth = hapd->dpp_auth;
+
+	if (!auth || !auth->resp_msg)
+		return;
+
+	wpa_printf(MSG_DEBUG,
+		   "DPP: Retry Authentication Response after timeout");
+	wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_TX "dst=" MACSTR
+		" freq=%u type=%d",
+		MAC2STR(auth->peer_mac_addr), auth->curr_freq,
+		DPP_PA_AUTHENTICATION_RESP);
+	hostapd_drv_send_action(hapd, auth->curr_freq, 500, auth->peer_mac_addr,
+				wpabuf_head(auth->resp_msg),
+				wpabuf_len(auth->resp_msg));
+}
+
+
+static void hostapd_dpp_auth_resp_retry(struct hostapd_data *hapd)
+{
+	struct dpp_authentication *auth = hapd->dpp_auth;
+	unsigned int wait_time, max_tries;
+
+	if (!auth || !auth->resp_msg)
+		return;
+
+	if (hapd->dpp_resp_max_tries)
+		max_tries = hapd->dpp_resp_max_tries;
+	else
+		max_tries = 5;
+	auth->auth_resp_tries++;
+	if (auth->auth_resp_tries >= max_tries) {
+		wpa_printf(MSG_INFO,
+			   "DPP: No confirm received from initiator - stopping exchange");
+		hostapd_drv_send_action_cancel_wait(hapd);
+		dpp_auth_deinit(hapd->dpp_auth);
+		hapd->dpp_auth = NULL;
+		return;
+	}
+
+	if (hapd->dpp_resp_retry_time)
+		wait_time = hapd->dpp_resp_retry_time;
+	else
+		wait_time = 1000;
+	wpa_printf(MSG_DEBUG,
+		   "DPP: Schedule retransmission of Authentication Response frame in %u ms",
+		wait_time);
+	eloop_cancel_timeout(hostapd_dpp_auth_resp_retry_timeout, hapd, NULL);
+	eloop_register_timeout(wait_time / 1000,
+			       (wait_time % 1000) * 1000,
+			       hostapd_dpp_auth_resp_retry_timeout, hapd, NULL);
+}
+
+
 void hostapd_dpp_tx_status(struct hostapd_data *hapd, const u8 *dst,
 			   const u8 *data, size_t data_len, int ok)
 {
+	struct dpp_authentication *auth = hapd->dpp_auth;
+
 	wpa_printf(MSG_DEBUG, "DPP: TX status: dst=" MACSTR " ok=%d",
 		   MAC2STR(dst), ok);
 	wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_TX_STATUS "dst=" MACSTR
@@ -295,15 +357,133 @@ void hostapd_dpp_tx_status(struct hostapd_data *hapd, const u8 *dst,
 	if (hapd->dpp_auth->remove_on_tx_status) {
 		wpa_printf(MSG_DEBUG,
 			   "DPP: Terminate authentication exchange due to an earlier error");
+		eloop_cancel_timeout(hostapd_dpp_init_timeout, hapd, NULL);
+		eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout,
+				     hapd, NULL);
+		eloop_cancel_timeout(hostapd_dpp_auth_resp_retry_timeout, hapd,
+				     NULL);
+		hostapd_drv_send_action_cancel_wait(hapd);
 		dpp_auth_deinit(hapd->dpp_auth);
 		hapd->dpp_auth = NULL;
 		return;
 	}
 
-	if (hapd->dpp_auth_ok_on_ack) {
+	if (hapd->dpp_auth_ok_on_ack)
-		hapd->dpp_auth_ok_on_ack = 0;
 		hostapd_dpp_auth_success(hapd, 1);
+
+	if (!is_broadcast_ether_addr(dst) && !ok) {
+		wpa_printf(MSG_DEBUG,
+			   "DPP: Unicast DPP Action frame was not ACKed");
+		if (auth->waiting_auth_resp) {
+			/* In case of DPP Authentication Request frame, move to
+			 * the next channel immediately. */
+			hostapd_drv_send_action_cancel_wait(hapd);
+			hostapd_dpp_auth_init_next(hapd);
+			return;
+		}
+		if (auth->waiting_auth_conf) {
+			hostapd_dpp_auth_resp_retry(hapd);
+			return;
+		}
 	}
+
+	if (!is_broadcast_ether_addr(dst) && auth->waiting_auth_resp && ok) {
+		/* Allow timeout handling to stop iteration if no response is
+		 * received from a peer that has ACKed a request. */
+		auth->auth_req_ack = 1;
+	}
+
+	if (!hapd->dpp_auth_ok_on_ack && hapd->dpp_auth->neg_freq > 0 &&
+	    hapd->dpp_auth->curr_freq != hapd->dpp_auth->neg_freq) {
+		wpa_printf(MSG_DEBUG,
+			   "DPP: Move from curr_freq %u MHz to neg_freq %u MHz for response",
+			   hapd->dpp_auth->curr_freq,
+			   hapd->dpp_auth->neg_freq);
+		hostapd_drv_send_action_cancel_wait(hapd);
+
+		if (hapd->dpp_auth->neg_freq !=
+		    hapd->iface->freq && hapd->iface->freq > 0) {
+			/* TODO: Listen operation on non-operating channel */
+			wpa_printf(MSG_INFO,
+				   "DPP: Listen operation on non-operating channel (%d MHz) is not yet supported (operating channel: %d MHz)",
+				   hapd->dpp_auth->neg_freq, hapd->iface->freq);
+		}
+	}
+
+	if (hapd->dpp_auth_ok_on_ack)
+		hapd->dpp_auth_ok_on_ack = 0;
+}
+
+
+static void hostapd_dpp_reply_wait_timeout(void *eloop_ctx, void *timeout_ctx)
+{
+	struct hostapd_data *hapd = eloop_ctx;
+	struct dpp_authentication *auth = hapd->dpp_auth;
+	unsigned int freq;
+	struct os_reltime now, diff;
+	unsigned int wait_time, diff_ms;
+
+	if (!auth || !auth->waiting_auth_resp)
+		return;
+
+	wait_time = hapd->dpp_resp_wait_time ?
+		hapd->dpp_resp_wait_time : 2000;
+	os_get_reltime(&now);
+	os_reltime_sub(&now, &hapd->dpp_last_init, &diff);
+	diff_ms = diff.sec * 1000 + diff.usec / 1000;
+	wpa_printf(MSG_DEBUG,
+		   "DPP: Reply wait timeout - wait_time=%u diff_ms=%u",
+		   wait_time, diff_ms);
+
+	if (auth->auth_req_ack && diff_ms >= wait_time) {
+		/* Peer ACK'ed Authentication Request frame, but did not reply
+		 * with Authentication Response frame within two seconds. */
+		wpa_printf(MSG_INFO,
+			   "DPP: No response received from responder - stopping initiation attempt");
+		wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_AUTH_INIT_FAILED);
+		hostapd_drv_send_action_cancel_wait(hapd);
+		hostapd_dpp_listen_stop(hapd);
+		dpp_auth_deinit(auth);
+		hapd->dpp_auth = NULL;
+		return;
+	}
+
+	if (diff_ms >= wait_time) {
+		/* Authentication Request frame was not ACK'ed and no reply
+		 * was receiving within two seconds. */
+		wpa_printf(MSG_DEBUG,
+			   "DPP: Continue Initiator channel iteration");
+		hostapd_drv_send_action_cancel_wait(hapd);
+		hostapd_dpp_listen_stop(hapd);
+		hostapd_dpp_auth_init_next(hapd);
+		return;
+	}
+
+	/* Driver did not support 2000 ms long wait_time with TX command, so
+	 * schedule listen operation to continue waiting for the response.
+	 *
+	 * DPP listen operations continue until stopped, so simply schedule a
+	 * new call to this function at the point when the two second reply
+	 * wait has expired. */
+	wait_time -= diff_ms;
+
+	freq = auth->curr_freq;
+	if (auth->neg_freq > 0)
+		freq = auth->neg_freq;
+	wpa_printf(MSG_DEBUG,
+		   "DPP: Continue reply wait on channel %u MHz for %u ms",
+		   freq, wait_time);
+	hapd->dpp_in_response_listen = 1;
+
+	if (freq != hapd->iface->freq && hapd->iface->freq > 0) {
+		/* TODO: Listen operation on non-operating channel */
+		wpa_printf(MSG_INFO,
+			   "DPP: Listen operation on non-operating channel (%d MHz) is not yet supported (operating channel: %d MHz)",
+			   freq, hapd->iface->freq);
+	}
+
+	eloop_register_timeout(wait_time / 1000, (wait_time % 1000) * 1000,
+			       hostapd_dpp_reply_wait_timeout, hapd, NULL);
 }
 
 
@@ -468,14 +648,110 @@ fail:
 }
 
 
+static void hostapd_dpp_init_timeout(void *eloop_ctx, void *timeout_ctx)
+{
+	struct hostapd_data *hapd = eloop_ctx;
+
+	if (!hapd->dpp_auth)
+		return;
+	wpa_printf(MSG_DEBUG, "DPP: Retry initiation after timeout");
+	hostapd_dpp_auth_init_next(hapd);
+}
+
+
+static int hostapd_dpp_auth_init_next(struct hostapd_data *hapd)
+{
+	struct dpp_authentication *auth = hapd->dpp_auth;
+	const u8 *dst;
+	unsigned int wait_time, max_wait_time, freq, max_tries, used;
+	struct os_reltime now, diff;
+
+	if (!auth)
+		return -1;
+
+	if (auth->freq_idx == 0)
+		os_get_reltime(&hapd->dpp_init_iter_start);
+
+	if (auth->freq_idx >= auth->num_freq) {
+		auth->num_freq_iters++;
+		if (hapd->dpp_init_max_tries)
+			max_tries = hapd->dpp_init_max_tries;
+		else
+			max_tries = 5;
+		if (auth->num_freq_iters >= max_tries || auth->auth_req_ack) {
+			wpa_printf(MSG_INFO,
+				   "DPP: No response received from responder - stopping initiation attempt");
+			wpa_msg(hapd->msg_ctx, MSG_INFO,
+				DPP_EVENT_AUTH_INIT_FAILED);
+			eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout,
+					     hapd, NULL);
+			hostapd_drv_send_action_cancel_wait(hapd);
+			dpp_auth_deinit(hapd->dpp_auth);
+			hapd->dpp_auth = NULL;
+			return -1;
+		}
+		auth->freq_idx = 0;
+		eloop_cancel_timeout(hostapd_dpp_init_timeout, hapd, NULL);
+		if (hapd->dpp_init_retry_time)
+			wait_time = hapd->dpp_init_retry_time;
+		else
+			wait_time = 10000;
+		os_get_reltime(&now);
+		os_reltime_sub(&now, &hapd->dpp_init_iter_start, &diff);
+		used = diff.sec * 1000 + diff.usec / 1000;
+		if (used > wait_time)
+			wait_time = 0;
+		else
+			wait_time -= used;
+		wpa_printf(MSG_DEBUG, "DPP: Next init attempt in %u ms",
+			   wait_time);
+		eloop_register_timeout(wait_time / 1000,
+				       (wait_time % 1000) * 1000,
+				       hostapd_dpp_init_timeout, hapd,
+				       NULL);
+		return 0;
+	}
+	freq = auth->freq[auth->freq_idx++];
+	auth->curr_freq = freq;
+
+	if (is_zero_ether_addr(auth->peer_bi->mac_addr))
+		dst = broadcast;
+	else
+		dst = auth->peer_bi->mac_addr;
+	hapd->dpp_auth_ok_on_ack = 0;
+	eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout, hapd, NULL);
+	wait_time = 2000; /* TODO: hapd->max_remain_on_chan; */
+	max_wait_time = hapd->dpp_resp_wait_time ?
+		hapd->dpp_resp_wait_time : 2000;
+	if (wait_time > max_wait_time)
+		wait_time = max_wait_time;
+	wait_time += 10; /* give the driver some extra time to complete */
+	eloop_register_timeout(wait_time / 1000, (wait_time % 1000) * 1000,
+			       hostapd_dpp_reply_wait_timeout, hapd, NULL);
+	wait_time -= 10;
+	if (auth->neg_freq > 0 && freq != auth->neg_freq) {
+		wpa_printf(MSG_DEBUG,
+			   "DPP: Initiate on %u MHz and move to neg_freq %u MHz for response",
+			   freq, auth->neg_freq);
+	}
+	wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_TX "dst=" MACSTR
+		" freq=%u type=%d",
+		MAC2STR(dst), freq, DPP_PA_AUTHENTICATION_REQ);
+	auth->auth_req_ack = 0;
+	os_get_reltime(&hapd->dpp_last_init);
+	return hostapd_drv_send_action(hapd, freq, wait_time,
+				       dst,
+				       wpabuf_head(hapd->dpp_auth->req_msg),
+				       wpabuf_len(hapd->dpp_auth->req_msg));
+}
+
+
 int hostapd_dpp_auth_init(struct hostapd_data *hapd, const char *cmd)
 {
 	const char *pos;
 	struct dpp_bootstrap_info *peer_bi, *own_bi = NULL;
-	const u8 *dst;
-	int res;
 	u8 allowed_roles = DPP_CAPAB_CONFIGURATOR;
-	struct dpp_configuration *conf_sta = NULL, *conf_ap = NULL;
+	unsigned int neg_freq = 0;
 
 	pos = os_strstr(cmd, " peer=");
 	if (!pos)
@@ -520,41 +796,37 @@ int hostapd_dpp_auth_init(struct hostapd_data *hapd, const char *cmd)
 			goto fail;
 	}
 
-	if (hapd->dpp_auth)
+	pos = os_strstr(cmd, " neg_freq=");
+	if (pos)
+		neg_freq = atoi(pos + 10);
+
+	if (hapd->dpp_auth) {
+		eloop_cancel_timeout(hostapd_dpp_init_timeout, hapd, NULL);
+		eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout,
+				     hapd, NULL);
+		eloop_cancel_timeout(hostapd_dpp_auth_resp_retry_timeout, hapd,
+				     NULL);
+		hostapd_drv_send_action_cancel_wait(hapd);
 		dpp_auth_deinit(hapd->dpp_auth);
-	/* TODO: hw_modes */
+	}
+
 	hapd->dpp_auth = dpp_auth_init(hapd->msg_ctx, peer_bi, own_bi,
-				       allowed_roles, 0, NULL, 0);
+				       allowed_roles, neg_freq,
+				       hapd->iface->hw_features,
+				       hapd->iface->num_hw_features);
 	if (!hapd->dpp_auth)
 		goto fail;
 	hostapd_dpp_set_testing_options(hapd, hapd->dpp_auth);
 	hostapd_dpp_set_configurator(hapd, hapd->dpp_auth, cmd);
 
-	/* TODO: Support iteration over all frequencies and filtering of
+	hapd->dpp_auth->neg_freq = neg_freq;
-	 * frequencies based on locally enabled channels that allow initiation
-	 * of transmission. */
 
-	if (is_zero_ether_addr(peer_bi->mac_addr)) {
+	if (!is_zero_ether_addr(peer_bi->mac_addr))
-		dst = broadcast;
-	} else {
-		dst = peer_bi->mac_addr;
 		os_memcpy(hapd->dpp_auth->peer_mac_addr, peer_bi->mac_addr,
 			  ETH_ALEN);
-	}
-	hapd->dpp_auth_ok_on_ack = 0;
 
-	wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_TX "dst=" MACSTR
+	return hostapd_dpp_auth_init_next(hapd);
-		" freq=%u type=%d",
-		MAC2STR(dst), hapd->dpp_auth->curr_freq,
-		DPP_PA_AUTHENTICATION_REQ);
-	res = hostapd_drv_send_action(hapd, hapd->dpp_auth->curr_freq, 0,
-				      dst, wpabuf_head(hapd->dpp_auth->req_msg),
-				      wpabuf_len(hapd->dpp_auth->req_msg));
-
-	return res;
 fail:
-	dpp_configuration_free(conf_sta);
-	dpp_configuration_free(conf_ap);
 	return -1;
 }
 
@@ -880,7 +1152,8 @@ static void hostapd_dpp_auth_success(struct hostapd_data *hapd, int initiator)
 
 
 static void hostapd_dpp_rx_auth_resp(struct hostapd_data *hapd, const u8 *src,
-				     const u8 *hdr, const u8 *buf, size_t len)
+				     const u8 *hdr, const u8 *buf, size_t len,
+				     unsigned int freq)
 {
 	struct dpp_authentication *auth = hapd->dpp_auth;
 	struct wpabuf *msg;
@@ -901,6 +1174,15 @@ static void hostapd_dpp_rx_auth_resp(struct hostapd_data *hapd, const u8 *src,
 		return;
 	}
 
+	eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout, hapd, NULL);
+
+	if (auth->curr_freq != freq && auth->neg_freq == freq) {
+		wpa_printf(MSG_DEBUG,
+			   "DPP: Responder accepted request for different negotiation channel");
+		auth->curr_freq = freq;
+	}
+
+	eloop_cancel_timeout(hostapd_dpp_init_timeout, hapd, NULL);
 	msg = dpp_auth_resp_rx(auth, hdr, buf, len);
 	if (!msg) {
 		if (auth->auth_resp_status == DPP_STATUS_RESPONSE_PENDING) {
@@ -1392,7 +1674,7 @@ void hostapd_dpp_rx_action(struct hostapd_data *hapd, const u8 *src,
 		hostapd_dpp_rx_auth_req(hapd, src, hdr, buf, len, freq);
 		break;
 	case DPP_PA_AUTHENTICATION_RESP:
-		hostapd_dpp_rx_auth_resp(hapd, src, hdr, buf, len);
+		hostapd_dpp_rx_auth_resp(hapd, src, hdr, buf, len, freq);
 		break;
 	case DPP_PA_AUTHENTICATION_CONF:
 		hostapd_dpp_rx_auth_conf(hapd, src, hdr, buf, len);
@@ -1461,6 +1743,10 @@ void hostapd_dpp_gas_status_handler(struct hostapd_data *hapd, int ok)
 	if (!hapd->dpp_auth)
 		return;
 
+	eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout, hapd, NULL);
+	eloop_cancel_timeout(hostapd_dpp_auth_resp_retry_timeout, hapd, NULL);
+	hostapd_drv_send_action_cancel_wait(hapd);
+
 	if (ok)
 		wpa_msg(hapd->msg_ctx, MSG_INFO, DPP_EVENT_CONF_SENT);
 	else
@@ -1718,6 +2004,9 @@ void hostapd_dpp_deinit(struct hostapd_data *hapd)
 #endif /* CONFIG_TESTING_OPTIONS */
 	if (!hapd->dpp_init_done)
 		return;
+	eloop_cancel_timeout(hostapd_dpp_reply_wait_timeout, hapd, NULL);
+	eloop_cancel_timeout(hostapd_dpp_init_timeout, hapd, NULL);
+	eloop_cancel_timeout(hostapd_dpp_auth_resp_retry_timeout, hapd, NULL);
 	dpp_auth_deinit(hapd->dpp_auth);
 	hapd->dpp_auth = NULL;
 	hostapd_dpp_pkex_remove(hapd, "*");

src/ap/hostapd.h

@@ -347,6 +347,7 @@ struct hostapd_data {
 	u8 dpp_allowed_roles;
 	int dpp_qr_mutual;
 	int dpp_auth_ok_on_ack;
+	int dpp_in_response_listen;
 	struct gas_query_ap *gas;
 	struct dpp_pkex *dpp_pkex;
 	struct dpp_bootstrap_info *dpp_pkex_bi;
@@ -354,6 +355,13 @@ struct hostapd_data {
 	char *dpp_pkex_identifier;
 	char *dpp_pkex_auth_cmd;
 	char *dpp_configurator_params;
+	struct os_reltime dpp_last_init;
+	struct os_reltime dpp_init_iter_start;
+	unsigned int dpp_init_max_tries;
+	unsigned int dpp_init_retry_time;
+	unsigned int dpp_resp_wait_time;
+	unsigned int dpp_resp_max_tries;
+	unsigned int dpp_resp_retry_time;
 #ifdef CONFIG_TESTING_OPTIONS
 	char *dpp_config_obj_override;
 	char *dpp_discovery_override;