ndef: Send empty WiFi carrier in Hr message when running as a STA

When running as a 802.11 STA, the Hr should contain an empty WiFi
carrier as we're just asking for WiFi availability from the peer.
Also when running in AP mode, an Hr is not a valid frame to send as
an AP will not be able to initiate the association.

diff --git a/src/ndef.c b/src/ndef.c
index 6790f8c..f86df89 100644 (file)
--- a/src/ndef.c
+++ b/src/ndef.c
@@ -1647,7 +1647,7 @@ static struct near_ndef_message *near_ndef_prepare_cfg_message(char *mime_type,
 
        DBG(" %s", mime_type);
 
-       if (mime_type == NULL || data == NULL || data_len <= 0)
+       if (mime_type == NULL)
                return NULL;
 
        msg = ndef_message_alloc_complete(mime_type, data_len, &cdr, cdr_len,
@@ -1656,7 +1656,8 @@ static struct near_ndef_message *near_ndef_prepare_cfg_message(char *mime_type,
                return NULL;
 
        /* store data */
-       memcpy(msg->data + msg->offset, data, data_len);
+       if (data)
+               memcpy(msg->data + msg->offset, data, data_len);
 
        return msg;
 }
@@ -1665,7 +1666,8 @@ static struct near_ndef_message *near_ndef_prepare_cfg_message(char *mime_type,
  * Prepare alternative carrier and configuration records
  * (e.g. bluetooth or wifi or Hc)
  */
-static int near_ndef_prepare_ac_and_cfg_records(enum handover_carrier carrier,
+static int near_ndef_prepare_ac_and_cfg_records(enum record_type type,
+                                       enum handover_carrier carrier,
                                        struct near_ndef_message **ac,
                                        struct near_ndef_message **cfg,
                                        struct near_ndef_mime_payload *mime,
@@ -1711,6 +1713,42 @@ static int near_ndef_prepare_ac_and_cfg_records(enum handover_carrier carrier,
                return -EINVAL;
        }
 
+       /*
+        * WiFi has to be handled a bit differently when we're trying
+        * to send the first Hr or Hs (i.e. remote_carrier == NULL).
+        * There are 2 invalid combinations:
+        *      a) AP mode and sending an Hr, as we won't be able to
+        *         initiate the association.
+        *      b) STA mode and sending an Hs, as the AP won't be able
+        *         initiate the association.
+        *
+        * a) is detected when local_carrier != NULL and record_type is
+        * Handover Request.
+        * b) is detected when local_carrier == NULL and record_type is
+        * Handover Select.
+        * In those 2 cases we return an error.
+        */
+       if (carrier == NEAR_CARRIER_WIFI && remote_carrier == NULL) {
+               if (local_carrier != NULL &&
+                               type == RECORD_TYPE_WKT_HANDOVER_REQUEST) {
+                       g_free(local_carrier);
+                       return -EINVAL;
+               }
+
+               if (local_carrier == NULL &&
+                               type == RECORD_TYPE_WKT_HANDOVER_SELECT)
+                       return -EINVAL;
+
+               if (local_carrier == NULL &&
+                               type == RECORD_TYPE_WKT_HANDOVER_REQUEST) {
+                       *cfg = near_ndef_prepare_cfg_message(mime_type,
+                                                       NULL, 0, cdr, 1);
+                       *ac = near_ndef_prepare_ac_message(CPS_UNKNOWN, cdr);
+
+                       return 0;
+               }
+       }
+
        if (local_carrier == NULL) {
                DBG("Unable to retrieve local carrier %s data", carrier_string);
                return -ESRCH;
@@ -1902,6 +1940,7 @@ static struct near_ndef_message *near_ndef_prepare_hs_reply(
                        goto fail;
 
                ret = near_ndef_prepare_ac_and_cfg_records(
+                                       RECORD_TYPE_WKT_HANDOVER_SELECT,
                                        remote_mime->handover.carrier_type,
                                        &ac_msg, &cfg_msg,
                                        remote_mime, remote_cfg);
@@ -2026,6 +2065,7 @@ near_ndef_prepare_ho_message(enum record_type type, GSList *carriers)
        /* Hr message should have at least one carrier */
        while (carriers) {
                ret = near_ndef_prepare_ac_and_cfg_records(
+                               type,
                                string2carrier(carriers->data),
                                &ac_msg, &cfg_msg, NULL, NULL);
                if (ret == 0) {