WPS: Fetch only the carrier record from wpa_supplicant for NFC

Since there could be multiple carrier records, it is cleaner to build
only the WPS carrier record instead of full NFC connection handover
request within wpa_supplicant.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/wps/ndef.c

@@ -170,10 +170,30 @@ struct wpabuf * ndef_build_wifi(const struct wpabuf *buf)
 }
 
 
+struct wpabuf * ndef_build_wifi_hc(int begin)
+{
+	struct wpabuf *hc, *carrier;
+
+	carrier = wpabuf_alloc(2 + os_strlen(wifi_handover_type));
+	if (carrier == NULL)
+		return NULL;
+	wpabuf_put_u8(carrier, 0x02); /* Carrier Type Format */
+	wpabuf_put_u8(carrier, os_strlen(wifi_handover_type));
+	wpabuf_put_str(carrier, wifi_handover_type);
+
+	hc = ndef_build_record((begin ? FLAG_MESSAGE_BEGIN : 0) |
+			       FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "Hc", 2,
+			       "0", 1, carrier);
+	wpabuf_free(carrier);
+
+	return hc;
+}
+
+
 struct wpabuf * ndef_build_wifi_hr(void)
 {
 	struct wpabuf *rn, *cr, *ac_payload, *ac, *hr_payload, *hr;
-	struct wpabuf *carrier, *hc;
+	struct wpabuf *hc;
 
 	rn = wpabuf_alloc(2);
 	if (rn == NULL)
@@ -224,18 +244,7 @@ struct wpabuf * ndef_build_wifi_hr(void)
 	if (hr == NULL)
 		return NULL;
 
-	carrier = wpabuf_alloc(2 + os_strlen(wifi_handover_type));
-	if (carrier == NULL) {
-		wpabuf_free(hr);
-		return NULL;
-	}
-	wpabuf_put_u8(carrier, 0x02); /* Carrier Type Format */
-	wpabuf_put_u8(carrier, os_strlen(wifi_handover_type));
-	wpabuf_put_str(carrier, wifi_handover_type);
-
-	hc = ndef_build_record(FLAG_MESSAGE_END | FLAG_TNF_NFC_FORUM, "Hc", 2,
-			       "0", 1, carrier);
-	wpabuf_free(carrier);
+	hc = ndef_build_wifi_hc(0);
 	if (hc == NULL) {
 		wpabuf_free(hr);
 		return NULL;

src/wps/wps.h

@@ -817,6 +817,7 @@ struct wpabuf * wps_nfc_token_gen(int ndef, int *id, struct wpabuf **pubkey,
 /* ndef.c */
 struct wpabuf * ndef_parse_wifi(const struct wpabuf *buf);
 struct wpabuf * ndef_build_wifi(const struct wpabuf *buf);
+struct wpabuf * ndef_build_wifi_hc(int begin);
 struct wpabuf * ndef_build_wifi_hr(void);
 
 #ifdef CONFIG_WPS_STRICT

wpa_supplicant/ctrl_iface.c

@@ -835,12 +835,13 @@ static int wpa_supplicant_ctrl_iface_wps_nfc_tag_read(
 
 
 static int wpas_ctrl_nfc_get_handover_req_wps(struct wpa_supplicant *wpa_s,
-					      char *reply, size_t max_len)
+					      char *reply, size_t max_len,
+					      int cr)
 {
 	struct wpabuf *buf;
 	int res;
 
-	buf = wpas_wps_nfc_handover_req(wpa_s);
+	buf = wpas_wps_nfc_handover_req(wpa_s, cr);
 	if (buf == NULL)
 		return -1;
 
@@ -869,9 +870,9 @@ static int wpas_ctrl_nfc_get_handover_req(struct wpa_supplicant *wpa_s,
 	if (os_strcmp(cmd, "NDEF") != 0)
 		return -1;
 
-	if (os_strcmp(pos, "WPS") == 0) {
-		return wpas_ctrl_nfc_get_handover_req_wps(wpa_s, reply,
-							  max_len);
+	if (os_strcmp(pos, "WPS") == 0 || os_strcmp(pos, "WPS-CR") == 0) {
+		return wpas_ctrl_nfc_get_handover_req_wps(
+			wpa_s, reply, max_len, os_strcmp(pos, "WPS-CR") == 0);
 	}
 
 	return -1;

wpa_supplicant/examples/wps-nfc.py

@@ -9,6 +9,8 @@
 import os
 import sys
 import time
+import random
+import StringIO
 
 import nfc
 import nfc.ndef
@@ -56,7 +58,7 @@ def wpas_get_handover_req():
     wpas = wpas_connect()
     if (wpas == None):
         return None
-    return wpas.request("NFC_GET_HANDOVER_REQ NDEF WPS").rstrip().decode("hex")
+    return wpas.request("NFC_GET_HANDOVER_REQ NDEF WPS-CR").rstrip().decode("hex")
 
 
 def wpas_put_handover_sel(message):
@@ -71,11 +73,21 @@ def wps_handover_init(peer):
 
     data = wpas_get_handover_req()
     if (data == None):
-        print "Could not get handover request message from wpa_supplicant"
+        print "Could not get handover request carrier record from wpa_supplicant"
         return
-    print "Handover request from wpa_supplicant: " + data.encode("hex")
-    message = nfc.ndef.Message(data)
-    print "Parsed handover request:"
+    print "Handover request carrier record from wpa_supplicant: " + data.encode("hex")
+    record = nfc.ndef.Record()
+    f = StringIO.StringIO(data)
+    record._read(f)
+    record = nfc.ndef.HandoverCarrierRecord(record)
+    print "Parsed handover request carrier record:"
+    print record.pretty()
+
+    message = nfc.ndef.HandoverRequestMessage(version="1.2")
+    message.nonce = random.randint(0, 0xffff)
+    message.add_carrier(record, "active")
+
+    print "Handover request:"
     print message.pretty()
 
     nfc.llcp.activate(peer);

wpa_supplicant/wps_supplicant.c

@@ -1977,8 +1977,10 @@ int wpas_wps_nfc_tag_read(struct wpa_supplicant *wpa_s,
 }
 
 
-struct wpabuf * wpas_wps_nfc_handover_req(struct wpa_supplicant *wpa_s)
+struct wpabuf * wpas_wps_nfc_handover_req(struct wpa_supplicant *wpa_s, int cr)
 {
+	if (cr)
+		return ndef_build_wifi_hc(1);
 	return ndef_build_wifi_hr();
 }
 

wpa_supplicant/wps_supplicant.h

@@ -66,7 +66,7 @@ struct wpabuf * wpas_wps_nfc_token(struct wpa_supplicant *wpa_s, int ndef);
 int wpas_wps_start_nfc(struct wpa_supplicant *wpa_s, const u8 *bssid);
 int wpas_wps_nfc_tag_read(struct wpa_supplicant *wpa_s,
 			  const struct wpabuf *data);
-struct wpabuf * wpas_wps_nfc_handover_req(struct wpa_supplicant *wpa_s);
+struct wpabuf * wpas_wps_nfc_handover_req(struct wpa_supplicant *wpa_s, int cr);
 struct wpabuf * wpas_wps_nfc_handover_sel(struct wpa_supplicant *wpa_s);
 int wpas_wps_nfc_rx_handover_req(struct wpa_supplicant *wpa_s,
 				 const struct wpabuf *data);