Add ScopedNodeId and return it by Session::GetPeer() (#16000)

* Add ScopedNodeId and return it by Session::GetPeer()

* Move ScopedNodeId to a new file

* Add guidance about PeerId class

* Update src/lib/core/ScopedNodeId.h

Co-authored-by: Jerry Johns <[email protected]>

* Restyle

* Undo Progress/Error delta in logging

Co-authored-by: Andrei Litvin <[email protected]>
Co-authored-by: Jerry Johns <[email protected]>

src/lib/core/PeerId.h

@@ -33,6 +33,11 @@ constexpr bool IsValidFabricId(FabricId aFabricId)
     return aFabricId != kUndefinedFabricId;
 }
 
+/* NOTE: PeerId should be only used by mDNS, because it contains a compressed fabric id which is not unique, and the compressed
+ * fabric id is only used for mDNS announcement. ScopedNodeId which contains a node id and fabirc index, should be used in prefer of
+ * PeerId. ScopedNodeId is locally unique.
+ */
+// TODO: remove PeerId usage outside lib/dns, move PeerId into lib/dns
 /// A peer is identified by a node id within a compressed fabric ID
 class PeerId
 {

src/lib/core/ScopedNodeId.h

@@ -0,0 +1,44 @@
+/*
+ *    Copyright (c) 2022 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#pragma once
+
+#include <lib/core/DataModelTypes.h>
+#include <lib/core/NodeId.h>
+
+namespace chip {
+
+/// The ScopedNodeId provides an identifier for an operational node on the network that is only valid for use within the current
+/// Matter stack instance. It is not to be exchanged or directly used remotely over the network.
+class ScopedNodeId
+{
+public:
+    ScopedNodeId() : mNodeId(kUndefinedNodeId), mFabricIndex(kUndefinedFabricIndex) {}
+    ScopedNodeId(NodeId nodeId, FabricIndex fabricIndex) : mNodeId(nodeId), mFabricIndex(fabricIndex) {}
+
+    NodeId GetNodeId() const { return mNodeId; }
+    FabricIndex GetFabricIndex() const { return mFabricIndex; }
+
+    bool IsOperational() const { return mFabricIndex != kUndefinedFabricIndex && IsOperationalNodeId(mNodeId); }
+    bool operator==(const ScopedNodeId & that) const { return (mNodeId == that.mNodeId) && (mFabricIndex == that.mFabricIndex); }
+    bool operator!=(const ScopedNodeId & that) const { return !(*this == that); }
+
+private:
+    NodeId mNodeId;
+    FabricIndex mFabricIndex;
+};
+
+} // namespace chip

src/transport/GroupSession.h

@@ -66,6 +66,8 @@ class IncomingGroupSession : public Session
     const char * GetSessionTypeString() const override { return "incoming group"; };
 #endif
 
+    ScopedNodeId GetPeer() const override { return ScopedNodeId(mSourceNodeId, GetFabricIndex()); }
+
     Access::SubjectDescriptor GetSubjectDescriptor() const override
     {
         Access::SubjectDescriptor subjectDescriptor;
@@ -131,6 +133,8 @@ class OutgoingGroupSession : public Session
     const char * GetSessionTypeString() const override { return "outgoing group"; };
 #endif
 
+    ScopedNodeId GetPeer() const override { return ScopedNodeId(); }
+
     Access::SubjectDescriptor GetSubjectDescriptor() const override
     {
         return Access::SubjectDescriptor(); // no subject exists for outgoing group session.

src/transport/SecureSession.cpp

@@ -20,6 +20,11 @@
 namespace chip {
 namespace Transport {
 
+ScopedNodeId SecureSession::GetPeer() const
+{
+    return ScopedNodeId(mPeerNodeId, GetFabricIndex());
+}
+
 Access::SubjectDescriptor SecureSession::GetSubjectDescriptor() const
 {
     Access::SubjectDescriptor subjectDescriptor;

src/transport/SecureSession.h

@@ -83,6 +83,7 @@ class SecureSession : public Session
     const char * GetSessionTypeString() const override { return "secure"; };
 #endif
 
+    ScopedNodeId GetPeer() const override;
     Access::SubjectDescriptor GetSubjectDescriptor() const override;
 
     bool RequireMRP() const override { return GetPeerAddress().GetTransportType() == Transport::Type::kUdp; }

src/transport/Session.h

@@ -18,6 +18,8 @@
 
 #include <credentials/FabricTable.h>
 #include <lib/core/CHIPConfig.h>
+#include <lib/core/PeerId.h>
+#include <lib/core/ScopedNodeId.h>
 #include <messaging/ReliableMessageProtocolConfig.h>
 #include <transport/SessionHolder.h>
 #include <transport/raw/PeerAddress.h>
@@ -65,6 +67,7 @@ class Session
     virtual void Retain() {}
     virtual void Release() {}
 
+    virtual ScopedNodeId GetPeer() const                               = 0;
     virtual Access::SubjectDescriptor GetSubjectDescriptor() const     = 0;
     virtual bool RequireMRP() const                                    = 0;
     virtual const ReliableMessageProtocolConfig & GetMRPConfig() const = 0;

src/transport/UnauthenticatedSessionTable.h

@@ -74,6 +74,8 @@ class UnauthenticatedSession : public Session, public ReferenceCounted<Unauthent
     void Retain() override { ReferenceCounted<UnauthenticatedSession, UnauthenticatedSessionDeleter, 0>::Retain(); }
     void Release() override { ReferenceCounted<UnauthenticatedSession, UnauthenticatedSessionDeleter, 0>::Release(); }
 
+    ScopedNodeId GetPeer() const override { return ScopedNodeId(kUndefinedNodeId, GetFabricIndex()); }
+
     Access::SubjectDescriptor GetSubjectDescriptor() const override
     {
         return Access::SubjectDescriptor(); // return an empty ISD for unauthenticated session.