P2P Workaround for OSX accept bug

There is a bug in accept for IPv6 sockets. Instead of returning -1
and setting errno to ECONNABORTED an invalid (>= 0) file descriptor
is returned, with the client address left unchanged. The uninitialized
client address causes the network package to throw a user error.

ouroboros-network-framework/src/Ouroboros/Network/Server2.hs

@@ -50,10 +50,8 @@ import           Data.Void (Void)
 import           Data.List (intercalate)
 import           Data.List.NonEmpty (NonEmpty)
 import qualified Data.List.NonEmpty as NonEmpty
-#if defined(mingw32_HOST_OS)
-import           System.IO.Error
-#else
 import           GHC.IO.Exception
+#if !defined(mingw32_HOST_OS)
 import           Foreign.C.Error
 #endif
 
@@ -176,9 +174,24 @@ run ServerArguments {
             throwIO e
   where
 
-#if !defined(mingw32_HOST_OS)
     iseCONNABORTED :: IOError -> Bool
+#if defined(mingw32_HOST_OS)
+    -- On Windows the network packet classifies all errors
+    -- as OtherError. This means that we're forced to match
+    -- on the error string. The text string comes from
+    -- the network package's winSockErr.c, and if it ever
+    -- changes we must update our text string too.
+    iseCONNABORTED (IOError _ _ _ "Software caused connection abort (WSAECONNABORTED)" _ _) = True
+    iseCONNABORTED _ = False
+#else
     iseCONNABORTED (IOError _ _ _ _ (Just cerrno) _) = eCONNABORTED == Errno cerrno
+#if defined(darwin_HOST_OS)
+    -- There is a bug in accept for IPv6 sockets. Instead of returning -1
+    -- and setting errno to ECONNABORTED an invalid (>= 0) file descriptor
+    -- is returned, with the client address left unchanged. The uninitialized
+    -- client address causes the network package to throw the user error below.
+    iseCONNABORTED (IOError _ UserError _ "Network.Socket.Types.peekSockAddr: address family '0' not supported." _ _) = True
+#endif
     iseCONNABORTED _ = False
 #endif
 
@@ -200,30 +213,18 @@ run ServerArguments {
       case result of
         (AcceptFailure err, acceptNext) -> do
           traceWith tracer (TrAcceptError err)
-          -- Try the determine if the connection was aborted by the remote end
+          -- Try to determine if the connection was aborted by the remote end
           -- before we could process the accept, or if it was a resource
           -- exaustion problem.
           -- NB. This piece of code is fragile and depends on specific
           -- strings/mappings in the network and base libraries.
           case fromException err of
              Just ioErr ->
-#if defined(mingw32_HOST_OS)
-                      -- On Windows the network packet classifies all errors
-                      -- as OtherError. This means that we're forced to match
-                      -- on the error string. The text string comes from
-                      -- the network package's winSockErr.c, and if it ever
-                      -- changes we must update our text string too.
-                      if ioeGetErrorString ioErr /=
-                          "Software caused connection abort (WSAECONNABORTED)"
-                         then throwIO ioErr
-                         else threadDelay 0.5 >>
-                             acceptLoop localAddress acceptNext
-#else
                if iseCONNABORTED ioErr
                   then threadDelay 0.5 >> acceptLoop localAddress acceptNext
                   else throwIO ioErr
-#endif
              Nothing -> throwIO err
+
         (Accepted socket peerAddr, acceptNext) -> do
           traceWith tracer (TrAcceptConnection peerAddr)
           -- using withAsync ensures that the thread that includes inbound