USIM refactor

src/ue/nas/mm/auth.cpp

@@ -63,20 +63,20 @@ void NasMm::receiveAuthenticationRequestEap(const nas::AuthenticationRequest &ms
         // Log.warning(Tag.CONFIG, "USE_SQN_HACK: %s", USE_SQN_HACK);
     }
 
-    if (USE_SQN_HACK)
+    /*if (USE_SQN_HACK)
     {
         auto ak = calculateMilenage(OctetString::FromSpare(6), receivedRand, false).ak;
         m_usim->m_sqn = OctetString::Xor(receivedAutn.subCopy(0, 6), ak);
-    }
+    }*/
 
-    auto milenage = calculateMilenage(m_usim->m_sqn, receivedRand, false);
+    auto milenage = calculateMilenage(m_usim->m_sqnMng->getSqn(), receivedRand, false);
     auto &res = milenage.res;
     auto &ck = milenage.ck;
     auto &ik = milenage.ik;
     auto &milenageAk = milenage.ak;
     auto &milenageMac = milenage.mac_a;
 
-    auto sqnXorAk = OctetString::Xor(m_usim->m_sqn, milenageAk);
+    auto sqnXorAk = OctetString::Xor(m_usim->m_sqnMng->getSqn(), milenageAk);
     auto ckPrimeIkPrime =
         keys::CalculateCkPrimeIkPrime(ck, ik, keys::ConstructServingNetworkName(*m_usim->m_currentPlmn), sqnXorAk);
     auto &ckPrime = ckPrimeIkPrime.first;
@@ -289,14 +289,14 @@ void NasMm::receiveAuthenticationRequest5gAka(const nas::AuthenticationRequest &
     auto &rand = msg.authParamRAND->value;
     auto &autn = msg.authParamAUTN->value;
 
-    auto milenage = calculateMilenage(m_usim->m_sqn, rand, false);
+    auto milenage = calculateMilenage(m_usim->m_sqnMng->getSqn(), rand, false);
     auto &res = milenage.res;
     auto &ck = milenage.ck;
     auto &ik = milenage.ik;
     auto ckIk = OctetString::Concat(ck, ik);
     auto &milenageAk = milenage.ak;
     auto &milenageMac = milenage.mac_a;
-    auto sqnXorAk = OctetString::Xor(m_usim->m_sqn, milenageAk);
+    auto sqnXorAk = OctetString::Xor(m_usim->m_sqnMng->getSqn(), milenageAk);
     auto snn = keys::ConstructServingNetworkName(*m_usim->m_currentPlmn);
 
     auto autnCheck = validateAutn(milenageAk, milenageMac, autn);
@@ -329,8 +329,8 @@ void NasMm::receiveAuthenticationRequest5gAka(const nas::AuthenticationRequest &
     }
     else if (autnCheck == EAutnValidationRes::SYNCHRONISATION_FAILURE)
     {
-        auto milenageForSync = calculateMilenage(m_usim->m_sqn, rand, true);
-        auto auts = keys::CalculateAuts(m_usim->m_sqn, milenageForSync.ak_r, milenageForSync.mac_s);
+        auto milenageForSync = calculateMilenage(m_usim->m_sqnMng->getSqn(), rand, true);
+        auto auts = keys::CalculateAuts(m_usim->m_sqnMng->getSqn(), milenageForSync.ak_r, milenageForSync.mac_s);
         sendFailure(nas::EMmCause::SYNCH_FAILURE, std::move(auts));
     }
     else
@@ -435,7 +435,7 @@ EAutnValidationRes NasMm::validateAutn(const OctetString &ak, const OctetString
     }
 
     // Verify that the received sequence number SQN is in the correct range
-    if (!m_usim->checkSqn(receivedSQN))
+    if (!m_usim->m_sqnMng->checkSqn(receivedSQN))
         return EAutnValidationRes::SYNCHRONISATION_FAILURE;
 
     // Check MAC

src/ue/nas/usim/sqn_mng.cpp

+//
+// This file is a part of UERANSIM open source project.
+// Copyright (c) 2021 ALİ GÜNGÖR.
+//
+// The software and all associated files are licensed under GPL-3.0
+// and subject to the terms and conditions defined in LICENSE file.
+//
+
+#include "sqn_mng.hpp"
+
+#include <stdexcept>
+
+namespace nr::ue
+{
+
+SqnManager::SqnManager(uint64_t indBitLen, uint64_t wrappingDelta, uint64_t limit)
+    : m_indBitLen{indBitLen}, m_wrappingDelta{wrappingDelta}, m_limit{limit}, m_sqnArr(1ull << m_indBitLen)
+{
+    if (m_indBitLen < 2 || m_indBitLen > 16)
+        throw std::runtime_error("bad indBitLen");
+}
+
+uint64_t SqnManager::getSeqFromSqn(uint64_t sqn) const
+{
+    sqn &= ~((1ull << m_indBitLen) - 1ull);
+    sqn >>= m_indBitLen;
+    sqn &= (1ull << 48ull) - 1ull;
+    return sqn;
+}
+
+uint64_t SqnManager::getIndFromSqn(uint64_t sqn) const
+{
+    return sqn & ((1ull << m_indBitLen) - 1ull);
+}
+
+uint64_t SqnManager::getSeqMs() const
+{
+    return getSeqFromSqn(getSqnUL());
+}
+
+uint64_t SqnManager::getSqnUL() const
+{
+    return *std::max_element(m_sqnArr.begin(), m_sqnArr.end());
+}
+
+bool SqnManager::checkSqn(uint64_t sqn)
+{
+    uint64_t seq = getSeqFromSqn(sqn);
+    uint64_t ind = getIndFromSqn(sqn);
+
+    if (seq - getSeqMs() > m_wrappingDelta)
+        return false;
+    if (getSeqMs() - seq >= m_limit)
+        return false;
+    if (seq <= getSeqFromSqn(m_sqnArr[ind]))
+        return false;
+
+    m_sqnArr[ind] = sqn;
+    return true;
+}
+
+bool SqnManager::checkSqn(const OctetString &sqn)
+{
+    OctetString str;
+    str.appendOctet2(0);
+    str.append(sqn);
+    return checkSqn(str.get8UL(0));
+}
+
+OctetString SqnManager::getSqn() const
+{
+    return OctetString::FromOctet8(getSqnUL()).subCopy(2);
+}
+
+} // namespace nr::ue

src/ue/nas/usim/sqn_mng.hpp

+//
+// This file is a part of UERANSIM open source project.
+// Copyright (c) 2021 ALİ GÜNGÖR.
+//
+// The software and all associated files are licensed under GPL-3.0
+// and subject to the terms and conditions defined in LICENSE file.
+//
+
+#pragma once
+
+#include <algorithm>
+#include <cstdint>
+#include <vector>
+
+#include <utils/octet_string.hpp>
+
+namespace nr::ue
+{
+
+class SqnManager
+{
+  private:
+    uint64_t m_indBitLen;
+    uint64_t m_wrappingDelta;
+    uint64_t m_limit;
+
+    std::vector<uint64_t> m_sqnArr;
+
+  public:
+    SqnManager(uint64_t indBitLen, uint64_t wrappingDelta, uint64_t limit);
+
+  private:
+    [[nodiscard]] uint64_t getSeqFromSqn(uint64_t sqn) const;
+    [[nodiscard]] uint64_t getIndFromSqn(uint64_t sqn) const;
+    [[nodiscard]] uint64_t getSeqMs() const;
+
+  public:
+    [[nodiscard]] uint64_t getSqnUL() const;
+    [[nodiscard]] OctetString getSqn() const;
+    bool checkSqn(uint64_t sqn);
+    bool checkSqn(const OctetString &sqn);
+};
+
+} // namespace nr::ue

src/ue/nas/usim/usim.cpp

@@ -20,7 +20,7 @@ void ue::Usim::initialize(bool hasSupi, const UeConfig::Initials &initials)
     m_defConfiguredNssai = initials.defaultConfiguredNssai;
     m_configuredNssai = initials.configuredNssai;
 
-    m_sqn = OctetString::FromSpare(6);
+    m_sqnMng = std::make_unique<SqnManager>(5ull, 1ull << 28ull, ~0ull);
 }
 
 bool Usim::isValid()
@@ -33,10 +33,4 @@ void Usim::invalidate()
     m_isValid = false;
 }
 
-bool Usim::checkSqn(const OctetString &sqn)
-{
-    // TODO
-    return false;
-}
-
 } // namespace nr::ue

src/ue/nas/usim/usim.hpp

@@ -8,9 +8,12 @@
 
 #pragma once
 
-#include <lib/nas/msg.hpp>
+#include "sqn_mng.hpp"
+
 #include <memory>
 #include <optional>
+
+#include <lib/nas/msg.hpp>
 #include <ue/types.hpp>
 #include <utils/common_types.hpp>
 #include <utils/octet_string.hpp>
@@ -49,6 +52,7 @@ class Usim
     OctetString m_rand{};
     OctetString m_res{};
     OctetString m_resStar{};
+    std::unique_ptr<SqnManager> m_sqnMng{};
 
     // NSSAI related
     NetworkSlice m_defConfiguredNssai{};
@@ -67,16 +71,11 @@ class Usim
     // eCall related
     bool m_isECallOnly{};
 
-    // SQN management
-    OctetString m_sqn{};
-
   public:
     void initialize(bool hasSupi, const UeConfig::Initials &initials);
 
     bool isValid();
     void invalidate();
-
-    bool checkSqn(const OctetString &sqn);
 };
 
 } // namespace nr::ue
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