Use exchange to send CASE session establishment messages

src/channel/ChannelContext.cpp

@@ -261,22 +261,23 @@ CHIP_ERROR ChannelContext::SendSessionEstablishmentMessage(const PacketHeader &
 CHIP_ERROR ChannelContext::HandlePairingMessage(const PacketHeader & packetHeader, const Transport::PeerAddress & peerAddress,
                                                 System::PacketBufferHandle && msg)
 {
-    if (IsCasePairing())
-        return mStateVars.mPreparing.mCasePairingSession->HandlePeerMessage(packetHeader, peerAddress, std::move(msg));
     return CHIP_ERROR_INCORRECT_STATE;
 }
 
 void ChannelContext::EnterCasePairingState()
 {
     mStateVars.mPreparing.mState              = PrepareState::kCasePairing;
     mStateVars.mPreparing.mCasePairingSession = Platform::New<CASESession>();
+
+    ExchangeContext * ctxt = mExchangeManager->NewContext(SecureSessionHandle(), mStateVars.mPreparing.mCasePairingSession);
+    VerifyOrReturn(ctxt != nullptr);
+
     // TODO: currently only supports IP/UDP paring
     Transport::PeerAddress addr;
     addr.SetTransportType(Transport::Type::kUdp).SetIPAddress(mStateVars.mPreparing.mAddress);
     CHIP_ERROR err = mStateVars.mPreparing.mCasePairingSession->EstablishSession(
-        addr, &mStateVars.mPreparing.mBuilder.GetOperationalCredentialSet(),
-        Optional<NodeId>::Value(mExchangeManager->GetSessionMgr()->GetLocalNodeId()),
-        mStateVars.mPreparing.mBuilder.GetPeerNodeId(), mExchangeManager->GetNextKeyId(), this);
+        addr, &mStateVars.mPreparing.mBuilder.GetOperationalCredentialSet(), mStateVars.mPreparing.mBuilder.GetPeerNodeId(),
+        mExchangeManager->GetNextKeyId(), ctxt, this);
     if (err != CHIP_NO_ERROR)
     {
         ExitCasePairingState();

src/channel/ChannelContext.h

@@ -27,7 +27,7 @@
 #include <channel/Channel.h>
 #include <lib/core/ReferenceCounted.h>
 #include <lib/mdns/platform/Mdns.h>
-#include <transport/CASESession.h>
+#include <protocols/secure_channel/CASESession.h>
 #include <transport/PeerConnectionState.h>
 #include <transport/SecureSessionMgr.h>
 

src/protocols/secure_channel/BUILD.gn

@@ -4,6 +4,8 @@ static_library("secure_channel") {
   output_name = "libSecureChannel"
 
   sources = [
+    "CASESession.cpp",
+    "CASESession.h",
     "NetworkProvisioning.cpp",
     "NetworkProvisioning.h",
     "PASESession.cpp",

src/transport/CASESession.h → src/protocols/secure_channel/CASESession.h

@@ -28,9 +28,13 @@
 #include <credentials/CHIPCert.h>
 #include <credentials/CHIPOperationalCredentials.h>
 #include <crypto/CHIPCryptoPAL.h>
+#include <messaging/ExchangeContext.h>
+#include <messaging/ExchangeDelegate.h>
 #include <protocols/secure_channel/Constants.h>
+#include <protocols/secure_channel/SessionEstablishmentExchangeDispatch.h>
 #include <support/Base64.h>
 #include <system/SystemPacketBuffer.h>
+#include <transport/PairingSession.h>
 #include <transport/PeerConnectionState.h>
 #include <transport/SecureSession.h>
 #include <transport/SessionEstablishmentDelegate.h>
@@ -59,13 +63,12 @@ struct CASESessionSerializable
     uint16_t mMessageDigestLen;
     uint8_t mMessageDigest[kSHA256_Hash_Length];
     uint8_t mPairingComplete;
-    NodeId mLocalNodeId;
     NodeId mPeerNodeId;
     uint16_t mLocalKeyId;
     uint16_t mPeerKeyId;
 };
 
-class DLL_EXPORT CASESession
+class DLL_EXPORT CASESession : public Messaging::ExchangeDelegateBase, public PairingSession
 {
 public:
     CASESession();
@@ -82,14 +85,13 @@ class DLL_EXPORT CASESession
      *
      * @param operationalCredentialSet      CHIP Certificate Set used to store the chain root of trust an validate peer node
      *                                      certificates
-     * @param myNodeId                      Node id of local node
      * @param myKeyId                       Key ID to be assigned to the secure session on the peer node
      * @param delegate                      Callback object
      *
      * @return CHIP_ERROR     The result of initialization
      */
-    CHIP_ERROR WaitForSessionEstablishment(OperationalCredentialSet * operationalCredentialSet, Optional<NodeId> myNodeId,
-                                           uint16_t myKeyId, SessionEstablishmentDelegate * delegate);
+    CHIP_ERROR WaitForSessionEstablishment(OperationalCredentialSet * operationalCredentialSet, uint16_t myKeyId,
+                                           SessionEstablishmentDelegate * delegate);
 
     /**
      * @brief
@@ -98,15 +100,15 @@ class DLL_EXPORT CASESession
      * @param peerAddress                   Address of peer with which to establish a session.
      * @param operationalCredentialSet      CHIP Certificate Set used to store the chain root of trust an validate peer node
      *                                      certificates
-     * @param myNodeId                      Node id of local node
      * @param peerNodeId                    Node id of the peer node
      * @param myKeyId                       Key ID to be assigned to the secure session on the peer node
+     * @param exchangeCtxt                  The exchange context to send and receive messages with the peer
      * @param delegate                      Callback object
      *
      * @return CHIP_ERROR      The result of initialization
      */
     CHIP_ERROR EstablishSession(const Transport::PeerAddress peerAddress, OperationalCredentialSet * operationalCredentialSet,
-                                Optional<NodeId> myNodeId, NodeId peerNodeId, uint16_t myKeyId,
+                                NodeId peerNodeId, uint16_t myKeyId, Messaging::ExchangeContext * exchangeCtxt,
                                 SessionEstablishmentDelegate * delegate);
 
     /**
@@ -120,19 +122,7 @@ class DLL_EXPORT CASESession
      *                    initialized once session establishment is complete
      * @return CHIP_ERROR The result of session derivation
      */
-    virtual CHIP_ERROR DeriveSecureSession(const uint8_t * info, size_t info_len, SecureSession & session);
-
-    /**
-     * @brief
-     *   Handler for peer's messages, exchanged during pairing handshake.
-     *
-     * @param packetHeader Message header for the received message
-     * @param peerAddress  Source of the message
-     * @param msg          Message sent by the peer
-     * @return CHIP_ERROR The result of message processing
-     */
-    virtual CHIP_ERROR HandlePeerMessage(const PacketHeader & packetHeader, const Transport::PeerAddress & peerAddress,
-                                         System::PacketBufferHandle msg);
+    virtual CHIP_ERROR DeriveSecureSession(const uint8_t * info, size_t info_len, SecureSession & session) override;
 
     /**
      * @brief
@@ -148,15 +138,19 @@ class DLL_EXPORT CASESession
      *
      * @return uint16_t The associated peer key id
      */
-    uint16_t GetPeerKeyId() { return mConnectionState.GetPeerKeyID(); }
+    uint16_t GetPeerKeyId() override { return mConnectionState.GetPeerKeyID(); }
 
     /**
      * @brief
      *  Return the associated local key id
      *
      * @return uint16_t The assocated local key id
      */
-    uint16_t GetLocalKeyId() { return mConnectionState.GetLocalKeyID(); }
+    uint16_t GetLocalKeyId() override { return mConnectionState.GetLocalKeyID(); }
+
+    const char * GetI2RSessionInfo() const override { return "Sigma I2R Key"; }
+
+    const char * GetR2ISessionInfo() const override { return "Sigma R2I Key"; }
 
     Transport::PeerConnectionState & PeerConnection() { return mConnectionState; }
 
@@ -180,6 +174,18 @@ class DLL_EXPORT CASESession
      **/
     CHIP_ERROR FromSerializable(const CASESessionSerializable & output);
 
+    SessionEstablishmentExchangeDispatch & MessageDispatch() { return mMessageDispatch; }
+
+    //// ExchangeDelegate Implementation ////
+    void OnMessageReceived(Messaging::ExchangeContext * ec, const PacketHeader & packetHeader, const PayloadHeader & payloadHeader,
+                           System::PacketBufferHandle payload) override;
+    void OnResponseTimeout(Messaging::ExchangeContext * ec) override;
+    Messaging::ExchangeMessageDispatch * GetMessageDispatch(Messaging::ReliableMessageMgr * rmMgr,
+                                                            SecureSessionMgr * sessionMgr) override
+    {
+        return &mMessageDispatch;
+    }
+
 private:
     enum SigmaErrorType : uint8_t
     {
@@ -190,17 +196,16 @@ class DLL_EXPORT CASESession
         kUnexpected           = 0xff,
     };
 
-    CHIP_ERROR Init(OperationalCredentialSet * operationalCredentialSet, Optional<NodeId> myNodeId, uint16_t myKeyId,
-                    SessionEstablishmentDelegate * delegate);
+    CHIP_ERROR Init(OperationalCredentialSet * operationalCredentialSet, uint16_t myKeyId, SessionEstablishmentDelegate * delegate);
 
     CHIP_ERROR SendSigmaR1();
-    CHIP_ERROR HandleSigmaR1_and_SendSigmaR2(const PacketHeader & header, const System::PacketBufferHandle & msg);
-    CHIP_ERROR HandleSigmaR1(const PacketHeader & header, const System::PacketBufferHandle & msg);
+    CHIP_ERROR HandleSigmaR1_and_SendSigmaR2(const System::PacketBufferHandle & msg);
+    CHIP_ERROR HandleSigmaR1(const System::PacketBufferHandle & msg);
     CHIP_ERROR SendSigmaR2();
-    CHIP_ERROR HandleSigmaR2_and_SendSigmaR3(const PacketHeader & header, const System::PacketBufferHandle & msg);
-    CHIP_ERROR HandleSigmaR2(const PacketHeader & header, const System::PacketBufferHandle & msg);
+    CHIP_ERROR HandleSigmaR2_and_SendSigmaR3(const System::PacketBufferHandle & msg);
+    CHIP_ERROR HandleSigmaR2(const System::PacketBufferHandle & msg);
     CHIP_ERROR SendSigmaR3();
-    CHIP_ERROR HandleSigmaR3(const PacketHeader & header, const System::PacketBufferHandle & msg);
+    CHIP_ERROR HandleSigmaR3(const System::PacketBufferHandle & msg);
 
     CHIP_ERROR SendSigmaR1Resume();
     CHIP_ERROR HandleSigmaR1Resume_and_SendSigmaR2Resume(const PacketHeader & header, const System::PacketBufferHandle & msg);
@@ -217,7 +222,7 @@ class DLL_EXPORT CASESession
     CHIP_ERROR ComputeIPK(const uint16_t sessionID, uint8_t * ipk, size_t ipkLen);
 
     void SendErrorMsg(SigmaErrorType errorCode);
-    void HandleErrorMsg(const PacketHeader & header, const System::PacketBufferHandle & msg);
+    void HandleErrorMsg(const System::PacketBufferHandle & msg);
 
     // TODO: Remove this and replace with system method to retrieve current time
     CHIP_ERROR SetEffectiveTime(void);
@@ -226,6 +231,9 @@ class DLL_EXPORT CASESession
 
     void Clear();
 
+    CHIP_ERROR ValidateReceivedMessage(Messaging::ExchangeContext * ec, const PacketHeader & packetHeader,
+                                       const PayloadHeader & payloadHeader, System::PacketBufferHandle msg);
+
     SessionEstablishmentDelegate * mDelegate = nullptr;
 
     Protocols::SecureChannel::MsgType mNextExpectedMsg = Protocols::SecureChannel::MsgType::CASE_SigmaErr;
@@ -242,14 +250,15 @@ class DLL_EXPORT CASESession
     uint8_t mIPK[kIPKSize];
     uint8_t mRemoteIPK[kIPKSize];
 
+    Messaging::ExchangeContext * mExchangeCtxt = nullptr;
+    SessionEstablishmentExchangeDispatch mMessageDispatch;
+
     struct SigmaErrorMsg
     {
         SigmaErrorType error;
     };
 
 protected:
-    NodeId mLocalNodeId = kUndefinedNodeId;
-
     bool mPairingComplete = false;
 
     Transport::PeerConnectionState mConnectionState;

src/protocols/secure_channel/SessionEstablishmentExchangeDispatch.cpp

@@ -32,7 +32,6 @@ CHIP_ERROR SessionEstablishmentExchangeDispatch::SendMessageImpl(SecureSessionHa
                                                                  System::PacketBufferHandle && message,
                                                                  EncryptedPacketBufferHandle * retainedMessage)
 {
-    ChipLogProgress(ExchangeManager, "SessionEstablishmentExchangeDispatch::SendMessageImpl  mTransportMgr %p", mTransportMgr);
     ReturnErrorOnFailure(payloadHeader.EncodeBeforeData(message));
     if (mTransportMgr != nullptr)
     {

src/protocols/secure_channel/tests/BUILD.gn

@@ -9,11 +9,13 @@ chip_test_suite("tests") {
   output_name = "libSecureChannelTests"
 
   test_sources = [
+    "TestCASESession.cpp",
     "TestPASESession.cpp",
     "TestStatusReport.cpp",
   ]
 
   public_deps = [
+    "${chip_root}/src/credentials/tests:cert_test_vectors",
     "${chip_root}/src/lib/core",
     "${chip_root}/src/lib/support",
     "${chip_root}/src/messaging/tests:helpers",