Export UDP file descriptor (for android)

llarp/ev/ev_libuv.cpp

@@ -66,6 +66,16 @@ namespace llarp::uv
     bool
     send(const SockAddr& dest, const llarp_buffer_t& buf) override;
 
+    std::optional<int>
+    file_descriptor() override
+    {
+#ifndef _WIN32
+      if (int fd = handle->fd(); fd >= 0)
+        return fd;
+#endif
+      return std::nullopt;
+    }
+
     void
     close() override;
 

llarp/ev/udp_handle.hpp

@@ -25,6 +25,14 @@ namespace llarp
     virtual void
     close() = 0;
 
+    // Returns the file descriptor of the socket, if available.  This generally exists only after
+    // listen() has been called, and never exists on Windows.
+    virtual std::optional<int>
+    file_descriptor()
+    {
+      return std::nullopt;
+    }
+
     // Base class destructor
     virtual ~UDPHandle() = default;
 

llarp/link/server.cpp

@@ -489,4 +489,10 @@ namespace llarp
     return true;
   }
 
+  std::optional<int>
+  ILinkLayer::GetUDPFD() const
+  {
+    return m_udp->file_descriptor();
+  }
+
 }  // namespace llarp

llarp/link/server.hpp

@@ -222,6 +222,10 @@ namespace llarp
       return m_Pending.size();
     }
 
+    // Returns the file description of the UDP server, if available.
+    std::optional<int>
+    GetUDPFD() const;
+
    private:
     const SecretKey& m_RouterEncSecret;
 

llarp/router/router.cpp

@@ -1326,7 +1326,7 @@ namespace llarp
         continue;
 
 #if defined(ANDROID)
-      m_OutboundUDPSocket = link->GetUDPSocket();
+      m_OutboundUDPSocket = link->GetUDPFD().value_or(-1);
 #endif
       _linkManager.AddLink(std::move(link), false);
       return true;