OPCFoundation#2055: System clock independent timeouts.

This is a barely tested proof-of-concept for timeouts independent of the system clock.
gailjkm · Apr 18, 2023 · 4253c70 · 4253c70
1 parent 8da702d
commit 4253c70
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Showing 3 changed files with 16 additions and 4 deletions.
diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/ChannelToken.cs b/Stack/Opc.Ua.Core/Stack/Tcp/ChannelToken.cs
@@ -57,6 +57,16 @@ public DateTime CreatedAt
             set { m_createdAt = value; }
         }
 
+		/// <summary>
+		/// When the token was created by the server (refers to the server's clock).
+		/// </summary>
+		public int CreatedAtTick
+		{
+			get { return m_createdAtTick; }
+			set { m_createdAtTick = value; }
+		}
+
+
         /// <summary>
         /// The lifetime of the token in milliseconds.
         /// </summary>
@@ -73,7 +83,7 @@ public bool Expired
         {
             get
             {
-                if (DateTime.UtcNow > m_createdAt.AddMilliseconds(m_lifetime))
+				if (Environment.TickCount - m_createdAtTick > m_lifetime)
                 {
                     return true;
                 }
@@ -89,7 +99,7 @@ public bool ActivationRequired
         {
             get
             {
-                if (DateTime.UtcNow > m_createdAt.AddMilliseconds(m_lifetime * TcpMessageLimits.TokenActivationPeriod))
+				if (Environment.TickCount - m_createdAtTick > (m_lifetime * TcpMessageLimits.TokenActivationPeriod))
                 {
                     return true;
                 }
@@ -219,6 +229,7 @@ public HMAC ServerHmac
         private uint m_channelId;
         private uint m_tokenId;
         private DateTime m_createdAt;
+		private int m_createdAtTick;
         private int m_lifetime;
         private byte[] m_clientNonce;
         private byte[] m_serverNonce;

diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.Symmetric.cs b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryChannel.Symmetric.cs
@@ -46,6 +46,7 @@ protected ChannelToken CreateToken()
             token.ChannelId = m_channelId;
             token.TokenId = 0;
             token.CreatedAt = DateTime.UtcNow;
+			token.CreatedAtTick = Environment.TickCount;
             token.Lifetime = (int)Quotas.SecurityTokenLifetime;
 
             Utils.LogInfo("ChannelId {0}: Token #{1} created. CreatedAt={2:HH:mm:ss.fff}. Lifetime={3}.",

diff --git a/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs b/Stack/Opc.Ua.Core/Stack/Tcp/UaSCBinaryClientChannel.cs
@@ -1162,9 +1162,9 @@ private void ScheduleTokenRenewal(ChannelToken token)
             }
 
             // calculate renewal timing based on token lifetime.
-            DateTime expiryTime = token.CreatedAt.AddMilliseconds(token.Lifetime);
+            int expiryTime = token.CreatedAtTick + token.Lifetime;
 
-            double timeToRenewal = ((expiryTime.Ticks - DateTime.UtcNow.Ticks) / TimeSpan.TicksPerMillisecond) * TcpMessageLimits.TokenRenewalPeriod;
+            double timeToRenewal = (expiryTime - Environment.TickCount) * TcpMessageLimits.TokenRenewalPeriod;
 
             if (timeToRenewal < 0)
             {