Include interface ID in the PeerAddress that gets handed up from UDP/TCP code

src/inet/TCPEndPoint.cpp

@@ -696,6 +696,67 @@ INET_ERROR TCPEndPoint::GetLocalInfo(IPAddress * retAddr, uint16_t * retPort)
     return res;
 }
 
+INET_ERROR TCPEndPoint::GetInterfaceId(InterfaceId * retInterface)
+{
+    if (!IsConnected())
+        return INET_ERROR_INCORRECT_STATE;
+
+#if CHIP_SYSTEM_CONFIG_USE_LWIP
+    // TODO: Does netif_get_by_index(mTCP->netif_idx) do the right thing?  I
+    // can't quite tell whether LwIP supports a specific interface id for TCP at
+    // all.  For now just claim no particular interface id.
+    *retInterface = INET_NULL_INTERFACEID;
+    return INET_NO_ERROR;
+#endif // CHIP_SYSTEM_CONFIG_USE_LWIP
+
+#if CHIP_SYSTEM_CONFIG_USE_SOCKETS
+    union
+    {
+        sockaddr any;
+        sockaddr_in6 in6;
+#if INET_CONFIG_ENABLE_IPV4
+        sockaddr_in in;
+#endif // INET_CONFIG_ENABLE_IPV4
+    } sa;
+
+    memset(&sa, 0, sizeof(sa));
+    socklen_t saLen = sizeof(sa);
+
+    if (getpeername(mSocket, &sa.any, &saLen) != 0)
+    {
+        return chip::System::MapErrorPOSIX(errno);
+    }
+
+    if (sa.any.sa_family == AF_INET6)
+    {
+        if (IPAddress::FromIPv6(sa.in6.sin6_addr).IsIPv6LinkLocal())
+        {
+            *retInterface = sa.in6.sin6_scope_id;
+        }
+        else
+        {
+            // TODO: Is there still a meaningful interface id in this case?
+            *retInterface = INET_NULL_INTERFACEID;
+        }
+        return INET_NO_ERROR;
+    }
+
+#if INET_CONFIG_ENABLE_IPV4
+    if (sa.any.sa_family == AF_INET)
+    {
+        // No interface id available for IPv4 sockets.
+        *retInterface = INET_NULL_INTERFACEID;
+    }
+#endif // INET_CONFIG_ENABLE_IPV4
+
+    return INET_ERROR_INCORRECT_STATE;
+
+#endif // CHIP_SYSTEM_CONFIG_USE_SOCKETS
+
+    *retInterface = INET_NULL_INTERFACEID;
+    return INET_NO_ERROR;
+}
+
 INET_ERROR TCPEndPoint::Send(System::PacketBufferHandle && data, bool push)
 {
     INET_ERROR res = INET_NO_ERROR;

src/inet/TCPEndPoint.h

@@ -192,6 +192,17 @@ class DLL_EXPORT TCPEndPoint : public EndPointBasis
      */
     INET_ERROR GetLocalInfo(IPAddress * retAddr, uint16_t * retPort);
 
+    /**
+     * @brief   Extract the interface id of the TCP endpoint.
+     *
+     * @param[out]  retInterface  The interface id.
+     *
+     * @retval  INET_NO_ERROR           success: address and port extracted.
+     * @retval  INET_ERROR_INCORRECT_STATE  TCP connection not established.
+     * @retval  INET_ERROR_CONNECTION_ABORTED   TCP connection no longer open.
+     */
+    INET_ERROR GetInterfaceId(InterfaceId * retInterface);
+
     /**
      * @brief   Send message text on TCP connection.
      *

src/transport/raw/PeerAddress.h

@@ -170,6 +170,10 @@ class PeerAddress
     }
     static PeerAddress TCP(const Inet::IPAddress & addr) { return PeerAddress(addr, Type::kTcp); }
     static PeerAddress TCP(const Inet::IPAddress & addr, uint16_t port) { return TCP(addr).SetPort(port); }
+    static PeerAddress TCP(const Inet::IPAddress & addr, uint16_t port, Inet::InterfaceId interface)
+    {
+        return TCP(addr).SetPort(port).SetInterface(interface);
+    }
 
 private:
     Inet::IPAddress mIPAddress;

src/transport/raw/TCP.cpp

@@ -356,9 +356,11 @@ INET_ERROR TCPBase::OnTcpReceive(Inet::TCPEndPoint * endPoint, System::PacketBuf
 {
     Inet::IPAddress ipAddress;
     uint16_t port;
+    Inet::InterfaceId interfaceId = INET_NULL_INTERFACEID;
 
     endPoint->GetPeerInfo(&ipAddress, &port);
-    PeerAddress peerAddress = PeerAddress::TCP(ipAddress, port);
+    endPoint->GetInterfaceId(&interfaceId);
+    PeerAddress peerAddress = PeerAddress::TCP(ipAddress, port, interfaceId);
 
     TCPBase * tcp  = reinterpret_cast<TCPBase *>(endPoint->AppState);
     CHIP_ERROR err = tcp->ProcessReceivedBuffer(endPoint, peerAddress, std::move(buffer));
@@ -379,9 +381,11 @@ void TCPBase::OnConnectionComplete(Inet::TCPEndPoint * endPoint, INET_ERROR inet
     TCPBase * tcp           = reinterpret_cast<TCPBase *>(endPoint->AppState);
     Inet::IPAddress ipAddress;
     uint16_t port;
+    Inet::InterfaceId interfaceId = INET_NULL_INTERFACEID;
 
     endPoint->GetPeerInfo(&ipAddress, &port);
-    PeerAddress addr = PeerAddress::TCP(ipAddress, port);
+    endPoint->GetInterfaceId(&interfaceId);
+    PeerAddress addr = PeerAddress::TCP(ipAddress, port, interfaceId);
 
     // Send any pending packets
     for (size_t i = 0; i < tcp->mPendingPacketsSize; i++)
@@ -507,9 +511,11 @@ void TCPBase::Disconnect(const PeerAddress & address)
         {
             Inet::IPAddress ipAddress;
             uint16_t port;
+            Inet::InterfaceId interfaceId = INET_NULL_INTERFACEID;
 
             mActiveConnections[i].mEndPoint->GetPeerInfo(&ipAddress, &port);
-            if (address == PeerAddress::TCP(ipAddress, port))
+            mActiveConnections[i].mEndPoint->GetInterfaceId(&interfaceId);
+            if (address == PeerAddress::TCP(ipAddress, port, interfaceId))
             {
                 // NOTE: this leaves the socket in TIME_WAIT.
                 // Calling Abort() would clean it since SO_LINGER would be set to 0,

src/transport/raw/UDP.cpp

@@ -105,7 +105,7 @@ void UDP::OnUdpReceive(Inet::IPEndPointBasis * endPoint, System::PacketBufferHan
 {
     CHIP_ERROR err          = CHIP_NO_ERROR;
     UDP * udp               = reinterpret_cast<UDP *>(endPoint->AppState);
-    PeerAddress peerAddress = PeerAddress::UDP(pktInfo->SrcAddress, pktInfo->SrcPort);
+    PeerAddress peerAddress = PeerAddress::UDP(pktInfo->SrcAddress, pktInfo->SrcPort, pktInfo->Interface);
 
     udp->HandleMessageReceived(peerAddress, std::move(buffer));