Add forgotten src/ap/utils.c file

Commit 32da61d9c9594a35db46dacd8ca3e0ae7167bac2 was supposed to add
this file.

src/ap/utils.c

@@ -0,0 +1,41 @@
+/*
+ * AP mode helper functions
+ * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "hostapd.h"
+
+
+int hostapd_register_probereq_cb(struct hostapd_data *hapd,
+				 void (*cb)(void *ctx, const u8 *sa,
+					    const u8 *ie, size_t ie_len),
+				 void *ctx)
+{
+	struct hostapd_probereq_cb *n;
+
+	n = os_realloc(hapd->probereq_cb, (hapd->num_probereq_cb + 1) *
+		       sizeof(struct hostapd_probereq_cb));
+	if (n == NULL)
+		return -1;
+
+	hapd->probereq_cb = n;
+	n = &hapd->probereq_cb[hapd->num_probereq_cb];
+	hapd->num_probereq_cb++;
+
+	n->cb = cb;
+	n->ctx = ctx;
+
+	return 0;
+}