From 6776f82e78826e2d34778c716d69493f18ef9871 Mon Sep 17 00:00:00 2001
From: Fletcher Dunn <fletcherd@valvesoftware.com>
Date: Wed, 27 May 2026 20:50:34 -0700
Subject: [PATCH] ICE client: Fix route determination

It needs the local candidate (with the relay, if present), not just the
interface.  And check for either candidate being relayed, then route is
relayed.
---
 .../clientlib/steamnetworkingsockets_ice_client.cpp   | 11 +++++++----
 .../clientlib/steamnetworkingsockets_ice_client.h     |  4 ++--
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.cpp b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.cpp
index baeee63..ab487de 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.cpp
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.cpp
@@ -1269,7 +1269,7 @@ void CSteamNetworkingICESession::SetSelectedCandidatePair( ICECandidatePair *pPa
     SpewMsg( "\n\nSelected candidate %s -> %s.\n\n", SteamNetworkingIPAddrRender( pPair->m_localCandidate.m_pInterface->m_pSocket->m_boundAddr ).c_str(), SteamNetworkingIPAddrRender( pPair->m_remoteCandidate.m_addr ).c_str() );
     m_pSelectedCandidatePair = pPair;
     if ( m_pCallbacks )
-        m_pCallbacks->OnConnectionSelected( *pPair->m_localCandidate.m_pInterface, pPair->m_remoteCandidate );
+        m_pCallbacks->OnConnectionSelected( pPair->m_localCandidate, pPair->m_remoteCandidate );
 }
 
 void CSteamNetworkingICESession::InternalDeleteCandidatePair( ICECandidatePair *pPair )
@@ -2437,14 +2437,17 @@ void CConnectionTransportP2PICE_Valve::OnLocalCandidateDiscovered( EICECandidate
     LocalCandidateGathered( type, std::move( c ) );
 }
 
-void CConnectionTransportP2PICE_Valve::OnConnectionSelected( const ICESessionInterface& localInterface, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate )
+void CConnectionTransportP2PICE_Valve::OnConnectionSelected( const ICELocalCandidate& localCandidate, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate )
 {
     ConnectionScopeLock lock( Connection(), "CConnectionTransportP2PICE_Valve::OnConnectionSelected");
 
     m_currentRouteRemoteAddress = remoteCandidate.m_addr;
-    m_eCurrentRouteKind = k_ESteamNetTransport_UDP;
-    if ( IsRemoteAddressOnLocalSubnet( localInterface.m_pSocket->m_boundAddr, localInterface.m_nPrefixLen, remoteCandidate.m_addr ) )
+    if ( localCandidate.IsRelay() || remoteCandidate.m_type == ICECandidateKind::Relayed )
+        m_eCurrentRouteKind = k_ESteamNetTransport_TURN;
+    else if ( IsRemoteAddressOnLocalSubnet( localCandidate.m_pInterface->m_pSocket->m_boundAddr, localCandidate.m_pInterface->m_nPrefixLen, remoteCandidate.m_addr ) )
         m_eCurrentRouteKind = k_ESteamNetTransport_UDPProbablyLocal;
+    else
+        m_eCurrentRouteKind = k_ESteamNetTransport_UDP;
     m_pingEndToEnd.Reset();
     m_pingEndToEnd.ReceivedPing( m_pICESession->GetPing(), SteamNetworkingSockets_GetLocalTimestamp() );
     Connection().TransportEndToEndConnectivityChanged( this, SteamNetworkingSockets_GetLocalTimestamp() );
diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.h b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.h
index 398c240..bdfcb4b 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.h
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_ice_client.h
@@ -452,7 +452,7 @@ namespace SteamNetworkingSocketsLib {
     public:
         virtual void OnLocalCandidateDiscovered( EICECandidateType type, const char *pszCandidateStr ) {}
         virtual void OnPacketReceived( const RecvPktInfo_t &info ) {}
-        virtual void OnConnectionSelected( const ICESessionInterface& localInterface, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate ) {}
+        virtual void OnConnectionSelected( const ICELocalCandidate& localCandidate, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate ) {}
     };
 
 
@@ -479,7 +479,7 @@ namespace SteamNetworkingSocketsLib {
     protected:
         virtual void OnLocalCandidateDiscovered( EICECandidateType type, const char *pszCandidateStr ) override;
         virtual void OnPacketReceived( const RecvPktInfo_t &info ) override;
-        virtual void OnConnectionSelected( const ICESessionInterface& localInterface, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate ) override;
+        virtual void OnConnectionSelected( const ICELocalCandidate& localCandidate, const CSteamNetworkingICESession::ICECandidateBase& remoteCandidate ) override;
     };
 
 } // namespace SteamNetworkingSocketsLib