From b5f165d48176a4c55c66160ce2ec0136b96f6430 Mon Sep 17 00:00:00 2001
From: Simon Walton <simon@highfidelity.io>
Date: Fri, 23 Mar 2018 16:55:19 -0700
Subject: [PATCH] Store a short ID with the Node on the domain-server side

---
 domain-server/src/DomainGatekeeper.cpp | 30 +++++++++++++++++++++++++-
 domain-server/src/DomainGatekeeper.h   | 14 ++++++++++++
 libraries/networking/src/NetworkPeer.h |  5 +++++
 3 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/domain-server/src/DomainGatekeeper.cpp b/domain-server/src/DomainGatekeeper.cpp
index 7d0b538f6e..748c089b21 100644
--- a/domain-server/src/DomainGatekeeper.cpp
+++ b/domain-server/src/DomainGatekeeper.cpp
@@ -14,6 +14,7 @@
 #include <openssl/err.h>
 #include <openssl/rsa.h>
 #include <openssl/x509.h>
+#include <random>
 
 #include <AccountManager.h>
 #include <Assignment.h>
@@ -26,7 +27,7 @@ using SharedAssignmentPointer = QSharedPointer<Assignment>;
 DomainGatekeeper::DomainGatekeeper(DomainServer* server) :
     _server(server)
 {
-
+    initLocalIDManagement();
 }
 
 void DomainGatekeeper::addPendingAssignedNode(const QUuid& nodeUUID, const QUuid& assignmentUUID,
@@ -525,6 +526,7 @@ SharedNodePointer DomainGatekeeper::addVerifiedNodeFromConnectRequest(const Node
 
     SharedNodePointer newNode = limitedNodeList->addOrUpdateNode(nodeID, nodeConnection.nodeType,
                                                                  nodeConnection.publicSockAddr, nodeConnection.localSockAddr);
+    newNode->setLocalID(findOrCreateLocalID(nodeID));
 
     // So that we can send messages to this node at will - we need to activate the correct socket on this node now
     newNode->activateMatchingOrNewSymmetricSocket(discoveredSocket);
@@ -1014,3 +1016,29 @@ void DomainGatekeeper::refreshGroupsCache() {
     _server->_settingsManager.debugDumpGroupsState();
 #endif
 }
+
+void DomainGatekeeper::initLocalIDManagement() {
+    std::uniform_int_distribution<quint16> sixteenBitRand;
+    std::random_device randomDevice;
+    std::default_random_engine engine {randomDevice()};
+    _currentLocalID = sixteenBitRand(engine);
+    // Ensure increment is odd.
+    _idIncrement = sixteenBitRand(engine) | 1;
+}
+
+Node::LocalID DomainGatekeeper::findOrCreateLocalID(const QUuid& uuid) {
+    auto existingLocalIDIt = _uuidToLocalID.find(uuid);
+    if (existingLocalIDIt != _uuidToLocalID.end()) {
+        return existingLocalIDIt->second;
+    }
+
+    Node::LocalID newLocalID;
+    do {
+        newLocalID = _currentLocalID;
+        _currentLocalID += _idIncrement;
+    } while (_localIDToUUID.find(newLocalID) != _localIDToUUID.end());
+
+    _uuidToLocalID.emplace(uuid, newLocalID);
+    _localIDToUUID.emplace(newLocalID, uuid);
+    return newLocalID;
+}
diff --git a/domain-server/src/DomainGatekeeper.h b/domain-server/src/DomainGatekeeper.h
index 09db075e07..896997a0e7 100644
--- a/domain-server/src/DomainGatekeeper.h
+++ b/domain-server/src/DomainGatekeeper.h
@@ -120,6 +120,20 @@ private:
     void getGroupMemberships(const QString& username);
     // void getIsGroupMember(const QString& username, const QUuid groupID);
     void getDomainOwnerFriendsList();
+
+    // Local ID management.
+    void initLocalIDManagement();
+    Node::LocalID findOrCreateLocalID(const QUuid& uuid);
+    struct UuidHash {
+        size_t operator()(const QUuid& uuid) const { return qHash(uuid); }
+    };
+    using UUIDToLocalID = std::unordered_map<QUuid, Node::LocalID, UuidHash> ;
+    using LocalIDToUUID = std::unordered_map<Node::LocalID, QUuid>;
+    UUIDToLocalID _uuidToLocalID;
+    LocalIDToUUID _localIDToUUID;
+
+    Node::LocalID _currentLocalID;
+    quint16 _idIncrement;
 };
 
 
diff --git a/libraries/networking/src/NetworkPeer.h b/libraries/networking/src/NetworkPeer.h
index 9842768b37..f36db402ce 100644
--- a/libraries/networking/src/NetworkPeer.h
+++ b/libraries/networking/src/NetworkPeer.h
@@ -39,6 +39,10 @@ public:
     const QUuid& getUUID() const { return _uuid; }
     void setUUID(const QUuid& uuid) { _uuid = uuid; }
 
+    using LocalID = quint16;
+    LocalID getLocalID() const { return _localID; }
+    void setLocalID(LocalID localID) { _localID = localID; }
+
     void softReset();
     void reset();
 
@@ -99,6 +103,7 @@ protected:
     void setActiveSocket(HifiSockAddr* discoveredSocket);
 
     QUuid _uuid;
+    LocalID _localID { 0 };
 
     HifiSockAddr _publicSocket;
     HifiSockAddr _localSocket;