Auth: Import milenage implementation from hostap (Jouni Malinen)

... and add integration into the osmo_auth core.
diff --git a/src/gsm/milenage/milenage.h b/src/gsm/milenage/milenage.h
new file mode 100644
index 0000000..d5054d6
--- /dev/null
+++ b/src/gsm/milenage/milenage.h
@@ -0,0 +1,33 @@
+/*
+ * UMTS AKA - Milenage algorithm (3GPP TS 35.205, .206, .207, .208)
+ * Copyright (c) 2006-2007 <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.
+ */
+
+#ifndef MILENAGE_H
+#define MILENAGE_H
+
+void milenage_generate(const u8 *opc, const u8 *amf, const u8 *k,
+		       const u8 *sqn, const u8 *_rand, u8 *autn, u8 *ik,
+		       u8 *ck, u8 *res, size_t *res_len);
+int milenage_auts(const u8 *opc, const u8 *k, const u8 *_rand, const u8 *auts,
+		  u8 *sqn);
+int gsm_milenage(const u8 *opc, const u8 *k, const u8 *_rand, u8 *sres,
+		 u8 *kc);
+int milenage_check(const u8 *opc, const u8 *k, const u8 *sqn, const u8 *_rand,
+		   const u8 *autn, u8 *ik, u8 *ck, u8 *res, size_t *res_len,
+		   u8 *auts);
+int milenage_f1(const u8 *opc, const u8 *k, const u8 *_rand,
+		const u8 *sqn, const u8 *amf, u8 *mac_a, u8 *mac_s);
+int milenage_f2345(const u8 *opc, const u8 *k, const u8 *_rand,
+		   u8 *res, u8 *ck, u8 *ik, u8 *ak, u8 *akstar);
+
+#endif /* MILENAGE_H */