mme: Add code to derive NAS token from NAS ul_count
NAS Token is derived from kasme and NAS ul_count as specified in 3GPP TS
33.401 A.9, and its LSB 16 bits passed to the network when mapping the GUTI to
RAI+PTMSI+PTIMSI_SIG.
Take the chance to move guti2rai_ptmsi() up to before the place it is
used.
Change-Id: I5e6003a2fe3e74cc93cfe4a288e6c114aa288d0b
diff --git a/mme/key_derivation.h b/mme/key_derivation.h
index 496f52b..ae15b65 100644
--- a/mme/key_derivation.h
+++ b/mme/key_derivation.h
@@ -19,3 +19,5 @@
void mme_kdf_enb(const uint8_t *kasme, uint32_t ul_count, uint8_t *kenb);
void mme_kdf_nh(const uint8_t *kasme, const uint8_t *sync_input, uint8_t *kenb);
+
+void mme_kdf_nas_token(const uint8_t *kasme, uint32_t ul_count, uint8_t *nas_token);