From f8486604c411b10c66716116961d3721b3d16533 Mon Sep 17 00:00:00 2001
From: Jason Rhinelander <jason@imaginary.ca>
Date: Tue, 2 Mar 2021 19:22:59 -0400
Subject: [PATCH] Export UDP file descriptor (for android)

---
 llarp/ev/ev_libuv.cpp   | 10 ++++++++++
 llarp/ev/udp_handle.hpp |  8 ++++++++
 llarp/link/server.cpp   |  6 ++++++
 llarp/link/server.hpp   |  4 ++++
 llarp/router/router.cpp |  2 +-
 5 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/llarp/ev/ev_libuv.cpp b/llarp/ev/ev_libuv.cpp
index c4b758515..02f836cf3 100644
--- a/llarp/ev/ev_libuv.cpp
+++ b/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;
 
diff --git a/llarp/ev/udp_handle.hpp b/llarp/ev/udp_handle.hpp
index 94d24c950..8169bd8a1 100644
--- a/llarp/ev/udp_handle.hpp
+++ b/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;
 
diff --git a/llarp/link/server.cpp b/llarp/link/server.cpp
index a9f0108c0..839a6a734 100644
--- a/llarp/link/server.cpp
+++ b/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
diff --git a/llarp/link/server.hpp b/llarp/link/server.hpp
index 01f54504e..2e9f828a0 100644
--- a/llarp/link/server.hpp
+++ b/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;
 
diff --git a/llarp/router/router.cpp b/llarp/router/router.cpp
index 0d22cd488..21507980f 100644
--- a/llarp/router/router.cpp
+++ b/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;