* fhandler_socket.cc (address_in_use): Disable. Add comment.

	(fhandler_socket::bind): Change comment to explain setting the
	SO_EXCLUSIVEADDRUSE socket option.  Remove code which checks for
	address in use.
	* net.cc (cygwin_setsockopt): Never set SO_REUSEADDR option.  Improve
	comment to compensate for the deleted comment in fhandler_socket::bind.
	* wincap.cc: Throughout, drop has_enhanced_socket_security from wincaps.
	* wincap.h (struct wincaps): Drop has_enhanced_socket_security flags
	and method.

1 files changed, 10 insertions, 32 deletions

diff --git a/winsup/cygwin/fhandler_socket.cc b/winsup/cygwin/fhandler_socket.cc
index b8dc02748..86dc92043 100644
--- a/winsup/cygwin/fhandler_socket.cc
+++ b/winsup/cygwin/fhandler_socket.cc
@@ -872,6 +872,11 @@ fhandler_socket::link (const char *newpath)
   return fhandler_base::link (newpath);
 }
 
+#if 0
+/* This doesn't work correctly.  It has been called in bind to check if a
+   loca address is still in use, but it disables bind in the SO_REUSEADDR
+   case even if only an accepted socket is still using the local address.
+   I keep this function in the code for later reference only. */
 static inline bool
 address_in_use (const struct sockaddr *addr)
 {
@@ -932,6 +937,7 @@ address_in_use (const struct sockaddr *addr)
     }
   return false;
 }
+#endif
 
 int
 fhandler_socket::bind (const struct sockaddr *name, int namelen)
@@ -1039,10 +1045,10 @@ fhandler_socket::bind (const struct sockaddr *name, int namelen)
     {
       if (!saw_reuseaddr ())
 	{
-	  /* If the application didn't explicitely call setsockopt
-	     (SO_REUSEADDR), enforce exclusive local address use using the
-	     SO_EXCLUSIVEADDRUSE socket option, to emulate POSIX socket
-	     behaviour more closely.
+	  /* If the application didn't explicitely request SO_REUSEADDR,
+	     enforce POSIX standard socket binding behaviour by setting the
+	     SO_EXCLUSIVEADDRUSE socket option.  See cygwin_setsockopt()
+	     for a more detailed description.
 
 	     KB 870562: Note that a bug in Win2K SP1-3 and XP up to SP1 only
 	     enables this option for users in the local administrators group. */
@@ -1052,34 +1058,6 @@ fhandler_socket::bind (const struct sockaddr *name, int namelen)
 				  (const char *) &on, sizeof on);
 	  debug_printf ("%d = setsockopt (SO_EXCLUSIVEADDRUSE), %E", ret);
 	}
-      else if (!wincap.has_enhanced_socket_security ())
-	{
-	  debug_printf ("SO_REUSEADDR set");
-	  /* There's a bug in SO_REUSEADDR handling in WinSock.
-	     Per standards, we must not be able to reuse a complete
-	     duplicate of a local TCP address (same IP, same port),
-	     even if SO_REUSEADDR has been set.  That's unfortunately
-	     possible in WinSock.
-
-	     So we're testing here if the local address is already in
-	     use and don't bind, if so.  This only works for OSes with
-	     IP Helper support and is, of course, still prone to races.
-
-	     However, we don't have to do this on systems supporting
-	     "enhanced socket security" (2K3 and later).  On these
-	     systems the default binding behaviour is exactly as you'd
-	     expect for SO_REUSEADDR, while setting SO_REUSEADDR re-enables
-	     the wrong behaviour.  So all we have to do on these newer
-	     systems is never to set SO_REUSEADDR but only to note that
-	     it has been set for the above SO_EXCLUSIVEADDRUSE setting.
-	     See setsockopt() in net.cc. */
-	  if (get_socket_type () == SOCK_STREAM && address_in_use (name))
-	    {
-	      debug_printf ("Local address in use, don't bind");
-	      set_errno (EADDRINUSE);
-	      goto out;
-	    }
-	}
       if (::bind (get_socket (), name, namelen))
 	set_winsock_errno ();
       else