From 4f62e6c08c6e8caf64a700ab2888d0b714fe725d Mon Sep 17 00:00:00 2001
From: Pedro Alvarez <pedro.alvarez@softwareradiosystems.com>
Date: Mon, 24 Feb 2020 19:35:43 +0000
Subject: [PATCH] Started to remove unecesssary lookups in
 gen_auth_info_answer_milenage

---
 srsepc/hdr/hss/hss.h  |  2 +-
 srsepc/src/hss/hss.cc | 26 +++++++++++++-------------
 2 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/srsepc/hdr/hss/hss.h b/srsepc/hdr/hss/hss.h
index 862386ce7..1ab8053d2 100644
--- a/srsepc/hdr/hss/hss.h
+++ b/srsepc/hdr/hss/hss.h
@@ -93,7 +93,7 @@ private:
   bool get_k_amf_opc_sqn(uint64_t imsi, uint8_t* k, uint8_t* amf, uint8_t* opc, uint8_t* sqn);
 
   void gen_auth_info_answer_xor(hss_ue_ctx_t* ue_ctx, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres);
-  bool gen_auth_info_answer_milenage(uint64_t imsi, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres);
+  void gen_auth_info_answer_milenage(hss_ue_ctx_t* ue_ctx, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres);
 
   bool resync_sqn_milenage(uint64_t imsi, uint8_t* auts);
   bool resync_sqn_xor(uint64_t imsi, uint8_t* auts);
diff --git a/srsepc/src/hss/hss.cc b/srsepc/src/hss/hss.cc
index a09521664..0cf15afc9 100644
--- a/srsepc/src/hss/hss.cc
+++ b/srsepc/src/hss/hss.cc
@@ -264,34 +264,33 @@ bool hss::gen_auth_info_answer(uint64_t imsi, uint8_t* k_asme, uint8_t* autn, ui
     return false;
   }
 
-  bool ret = false; // FIXME
   switch (ue_ctx->algo) {
     case HSS_ALGO_XOR:
       gen_auth_info_answer_xor(ue_ctx, k_asme, autn, rand, xres);
       break;
     case HSS_ALGO_MILENAGE:
-      ret = gen_auth_info_answer_milenage(imsi, k_asme, autn, rand, xres);
+      gen_auth_info_answer_milenage(ue_ctx, k_asme, autn, rand, xres);
       break;
   }
   increment_ue_sqn(imsi);
-  return ret;
+  return true;
 }
 
-bool hss::gen_auth_info_answer_milenage(uint64_t imsi, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres)
+void hss::gen_auth_info_answer_milenage(hss_ue_ctx_t* ue_ctx, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres)
 {
-  uint8_t k[16];
-  uint8_t amf[2];
-  uint8_t opc[16];
-  uint8_t sqn[6];
+  // Get K, AMF, OPC and SQN
+  uint8_t *k = ue_ctx->key;
+  uint8_t *amf = ue_ctx->amf;
+  uint8_t *opc = ue_ctx->opc;
+  uint8_t *sqn = ue_ctx->sqn;
 
+  // Temp variables
+  uint8_t xdout[16];
   uint8_t ck[16];
   uint8_t ik[16];
   uint8_t ak[6];
   uint8_t mac[8];
 
-  if (!get_k_amf_opc_sqn(imsi, k, amf, opc, sqn)) {
-    return false;
-  }
   gen_rand(rand);
 
   srslte::security_milenage_f2345(k, opc, rand, xres, ck, ik, ak);
@@ -327,8 +326,9 @@ bool hss::gen_auth_info_answer_milenage(uint64_t imsi, uint8_t* k_asme, uint8_t*
   }
   m_hss_log->debug_hex(autn, 16, "User AUTN: ");
 
-  set_last_rand(imsi, rand);
-  return true;
+  // Set last RAND
+  memcpy(ue_ctx->last_rand, rand, 16);
+  return;
 }
 
 void hss::gen_auth_info_answer_xor(hss_ue_ctx_t* ue_ctx, uint8_t* k_asme, uint8_t* autn, uint8_t* rand, uint8_t* xres)