From 8f121c1e7c3e052ffcb63904f56de4eec7741dc2 Mon Sep 17 00:00:00 2001
From: Piotr Krysik <ptrkrysik@gmail.com>
Date: Thu, 30 Mar 2017 10:55:08 +0200
Subject: Added interpretation of SC (start ciphering) field in cmc extractor

---
 include/grgsm/misc_utils/extract_cmc.h |  1 +
 lib/misc_utils/extract_cmc_impl.cc     | 12 +++++++++---
 lib/misc_utils/extract_cmc_impl.h      |  2 ++
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/grgsm/misc_utils/extract_cmc.h b/include/grgsm/misc_utils/extract_cmc.h
index 8af12be..7b31564 100755
--- a/include/grgsm/misc_utils/extract_cmc.h
+++ b/include/grgsm/misc_utils/extract_cmc.h
@@ -52,6 +52,7 @@ namespace gr {
       static sptr make();
       virtual std::vector<int> get_framenumbers() = 0;
       virtual std::vector<int> get_a5_versions() = 0;
+      virtual std::vector<int> get_start_ciphering() = 0;
     };
 
   } // namespace gsm
diff --git a/lib/misc_utils/extract_cmc_impl.cc b/lib/misc_utils/extract_cmc_impl.cc
index b367def..5fa6a6b 100755
--- a/lib/misc_utils/extract_cmc_impl.cc
+++ b/lib/misc_utils/extract_cmc_impl.cc
@@ -42,10 +42,11 @@ namespace gr {
 
         if((msg_elements[3] & 0xF) == 0x6 && msg_elements[4] == 0x35)
         {
-            
-            int frame_nr = be32toh(header->frame_number);
-            int a5_version = ((msg_elements[5] & 0xE) >> 1) + 1;
 
+            int frame_nr = be32toh(header->frame_number);
+            int a5_version = ((msg_elements[5] & 0xE) >> 1) + 1; //10.5.2.9 Cipher Mode Setting
+            int start_ciphering = ((msg_elements[5] & 0x1));
+            d_start_ciphering.push_back(start_ciphering);
             d_framenumbers.push_back(frame_nr);
             d_a5_versions.push_back(a5_version);
         }
@@ -60,6 +61,11 @@ namespace gr {
     {
         return d_a5_versions;
     }
+
+    std::vector<int> extract_cmc_impl::get_start_ciphering()
+    {
+        return d_start_ciphering;
+    }
     
     extract_cmc::sptr
     extract_cmc::make()
diff --git a/lib/misc_utils/extract_cmc_impl.h b/lib/misc_utils/extract_cmc_impl.h
index fe97f22..fe03bc8 100755
--- a/lib/misc_utils/extract_cmc_impl.h
+++ b/lib/misc_utils/extract_cmc_impl.h
@@ -34,9 +34,11 @@ namespace gr {
       void process_messages(pmt::pmt_t msg);
       std::vector<int> d_framenumbers;
       std::vector<int> d_a5_versions;
+      std::vector<int> d_start_ciphering;
      public:
       virtual std::vector<int> get_framenumbers();
       virtual std::vector<int> get_a5_versions();
+      virtual std::vector<int> get_start_ciphering();
       extract_cmc_impl();
       ~extract_cmc_impl();
     };
-- 
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