Making ParseSigma1 static and not dependent on class state

Author: Alami-Amine

src/protocols/secure_channel/CASESession.cpp

@@ -1100,6 +1100,7 @@ CASESession::NextStep CASESession::HandleSigma1(System::PacketBufferHandle && ms
     // Set the MRP parameters provided in the Sigma1 message
     if (parsedSigma1.initiatorMrpParamsPresent)
     {
+        SetRemoteSessionParameters(parsedSigma1.initiatorSessionParams);
         mExchangeCtxt.Value()->GetSessionHandle()->AsUnauthenticatedSession()->SetRemoteSessionParameters(
             GetRemoteSessionParameters());
     }
@@ -2324,7 +2325,8 @@ CHIP_ERROR CASESession::ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader,
     CHIP_ERROR err = tlvReader.Next();
     if (err == CHIP_NO_ERROR && tlvReader.GetTag() == AsTlvContextTag(Sigma1Tags::kInitiatorSessionParams))
     {
-        ReturnErrorOnFailure(DecodeMRPParametersIfPresent(AsTlvContextTag(Sigma1Tags::kInitiatorSessionParams), tlvReader));
+        ReturnErrorOnFailure(DecodeMRPParametersIfPresent(AsTlvContextTag(Sigma1Tags::kInitiatorSessionParams), tlvReader,
+                                                          outParsedSigma1.initiatorSessionParams));
         outParsedSigma1.initiatorMrpParamsPresent = true;
 
         err = tlvReader.Next();

src/protocols/secure_channel/CASESession.h

@@ -223,6 +223,7 @@ class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,
     {
         ByteSpan initiatorEphPubKey;
         bool initiatorMrpParamsPresent = false;
+        SessionParameters initiatorSessionParams;
     };
 
     struct EncodeSigma2Inputs
@@ -275,7 +276,7 @@ class DLL_EXPORT CASESession : public Messaging::UnsolicitedMessageHandler,
      * and the resumptionID and initiatorResumeMIC fields will be set to
      * valid values, or the sessionResumptionRequested field will be set to false.
      */
-    CHIP_ERROR ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, ParsedSigma1 & parsedMessage);
+    static CHIP_ERROR ParseSigma1(TLV::ContiguousBufferTLVReader & tlvReader, ParsedSigma1 & parsedMessage);
 
     /**
      * @brief  Encodes a Sigma2 message into TLV format and allocates a buffer for it, which is owned by the PacketBufferHandle

src/protocols/secure_channel/tests/TestCASESession.cpp

@@ -760,10 +760,9 @@ static CHIP_ERROR EncodeSigma1Helper(MutableByteSpan & buf)
                                                                                                                                    \
         TLV::ContiguousBufferTLVReader reader;                                                                                     \
         reader.Init(buf);                                                                                                          \
-        CASESessionAccess session;                                                                                                 \
         CASESessionAccess::ParsedSigma1 parsedSigma1;                                                                              \
                                                                                                                                    \
-        EXPECT_EQ(session.ParseSigma1(reader, parsedSigma1) == CHIP_NO_ERROR, params::kExpectSuccess);                             \
+        EXPECT_EQ(CASESessionAccess::ParseSigma1(reader, parsedSigma1) == CHIP_NO_ERROR, params::kExpectSuccess);                  \
         if (params::kExpectSuccess)                                                                                                \
         {                                                                                                                          \
             EXPECT_EQ(parsedSigma1.sessionResumptionRequested,                                                                     \
@@ -936,10 +935,9 @@ TEST_F(TestCASESession, EncodeSigma1Test)
         System::PacketBufferTLVReader tlvReader;
         tlvReader.Init(std::move(msg1));
 
-        CASESessionAccess session;
         CASESessionAccess::ParsedSigma1 parsedMessage;
 
-        EXPECT_EQ(CHIP_NO_ERROR, session.ParseSigma1(tlvReader, parsedMessage));
+        EXPECT_EQ(CHIP_NO_ERROR, CASESessionAccess::ParseSigma1(tlvReader, parsedMessage));
 
         // compare parsed values with original values
         EXPECT_TRUE(parsedMessage.initiatorRandom.data_equal(encodeParams.initiatorRandom));
@@ -970,10 +968,9 @@ TEST_F(TestCASESession, EncodeSigma1Test)
         System::PacketBufferTLVReader tlvReader;
         tlvReader.Init(std::move(msg2));
 
-        CASESessionAccess session;
         CASESessionAccess::ParsedSigma1 parsedMessage;
 
-        EXPECT_EQ(CHIP_NO_ERROR, session.ParseSigma1(tlvReader, parsedMessage));
+        EXPECT_EQ(CHIP_NO_ERROR, CASESessionAccess::ParseSigma1(tlvReader, parsedMessage));
 
         // RoundTrip
         EXPECT_TRUE(parsedMessage.initiatorRandom.data_equal(encodeParams.initiatorRandom));
@@ -1111,8 +1108,8 @@ struct SessionResumptionTestStorage : SessionResumptionStorage
 {
     SessionResumptionTestStorage(CHIP_ERROR findMethodReturnCode, ScopedNodeId peerNodeId, ResumptionIdStorage * resumptionId,
                                  Crypto::P256ECDHDerivedSecret * sharedSecret) :
-        mFindMethodReturnCode(findMethodReturnCode),
-        mPeerNodeId(peerNodeId), mResumptionId(resumptionId), mSharedSecret(sharedSecret)
+        mFindMethodReturnCode(findMethodReturnCode), mPeerNodeId(peerNodeId), mResumptionId(resumptionId),
+        mSharedSecret(sharedSecret)
     {}
     SessionResumptionTestStorage(CHIP_ERROR findMethodReturnCode) : mFindMethodReturnCode(findMethodReturnCode) {}
     CHIP_ERROR FindByScopedNodeId(const ScopedNodeId & node, ResumptionIdStorage & resumptionId,