From b6e0bd55fc89e346ce436cd38d67a240c8e83a6f Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Thu, 1 Oct 2026 10:28:16 +1000
Subject: [PATCH] [idd] network: preserve video sessions during reconfigure

A video configuration epoch can advance while client feedback for the
previous epoch is still in flight. Treat structurally valid stale video
control packets as obsolete instead of terminating the QUIC session.
---
 idd/LGIdd/transport/network/CNetworkVideo.cpp | 30 ++++++++++++++-----
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/idd/LGIdd/transport/network/CNetworkVideo.cpp b/idd/LGIdd/transport/network/CNetworkVideo.cpp
index 0380dcd9..97485d09 100644
--- a/idd/LGIdd/transport/network/CNetworkVideo.cpp
+++ b/idd/LGIdd/transport/network/CNetworkVideo.cpp
@@ -2233,6 +2233,8 @@ NetworkVideoPacketResult CNetworkVideo::HandlePacket(
   if (!DeliverySupported(peer->info, delivery))
     return NetworkVideoPacketResult::INVALID;
 
+  /* A configuration update crosses client traffic already in flight. Decode
+   * and validate stale messages, but do not make their epoch mismatch fatal. */
   switch (packet.envelope.messageType)
   {
     case LG_NET_VIDEO_MESSAGE_SUBSCRIBE:
@@ -2283,10 +2285,13 @@ NetworkVideoPacketResult CNetworkVideo::HandlePacket(
       LGNetVideoControl control = {};
       if (lgNetVideoControlDecode(&control, packet.payload,
             packet.payloadLength) != LG_NET_PARSE_OK ||
-          control.streamID != STREAM_ID ||
-          (control.configEpoch &&
-            control.configEpoch != peer->componentEpoch))
+          control.streamID != STREAM_ID)
         return NetworkVideoPacketResult::INVALID;
+      if ((control.configEpoch &&
+            control.configEpoch != peer->componentEpoch) ||
+          (packet.envelope.componentEpoch &&
+            packet.envelope.componentEpoch != peer->componentEpoch))
+        return NetworkVideoPacketResult::IGNORED;
       m_impl->DropPeerSendsNL(*peer);
       peer->subscribed      = false;
       peer->configured      = false;
@@ -2304,9 +2309,14 @@ NetworkVideoPacketResult CNetworkVideo::HandlePacket(
       LGNetVideoControl control = {};
       if (lgNetVideoControlDecode(&control, packet.payload,
             packet.payloadLength) != LG_NET_PARSE_OK ||
-          control.streamID != STREAM_ID || !peer->subscribed ||
-          (control.configEpoch &&
-            control.configEpoch != peer->componentEpoch))
+          control.streamID != STREAM_ID)
+        return NetworkVideoPacketResult::INVALID;
+      if ((control.configEpoch &&
+            control.configEpoch != peer->componentEpoch) ||
+          (packet.envelope.componentEpoch &&
+            packet.envelope.componentEpoch != peer->componentEpoch))
+        return NetworkVideoPacketResult::IGNORED;
+      if (!peer->subscribed)
         return NetworkVideoPacketResult::INVALID;
       peer->keyframePending = true;
       break;
@@ -2321,10 +2331,14 @@ NetworkVideoPacketResult CNetworkVideo::HandlePacket(
       LGNetVideoFeedback feedback = {};
       if (lgNetVideoFeedbackDecode(&feedback, packet.payload,
             packet.payloadLength) != LG_NET_PARSE_OK ||
-          feedback.streamID != STREAM_ID || !peer->subscribed ||
-          packet.envelope.componentEpoch != peer->componentEpoch ||
+          feedback.streamID != STREAM_ID ||
+          !packet.envelope.componentEpoch ||
           feedback.highestSeenFrameID > peer->lastFrameID)
         return NetworkVideoPacketResult::INVALID;
+      if (packet.envelope.componentEpoch != peer->componentEpoch)
+        return NetworkVideoPacketResult::IGNORED;
+      if (!peer->subscribed)
+        return NetworkVideoPacketResult::INVALID;
       peer->feedback       = feedback;
       peer->lastCompleteID = feedback.lastCompleteFrameID;
       peer->congested      =