Fixed unintentional usage of SO_REUSEPORT on W32.

2 files changed, 8 insertions, 3 deletions

diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index c4ea8d0b..3e2d9109 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -4990,8 +4990,11 @@ MHD_start_daemon_va (unsigned int flags,
       /* Apply the socket options according to listening_address_reuse. */
       if (0 == daemon->listening_address_reuse)
         {
-          /* No user requirement, use "traditional" default SO_REUSEADDR,
-           and do not fail if it doesn't work */
+#ifndef _WIN32
+          /* No user requirement, use "traditional" default SO_REUSEADDR
+           * on non-W32 platforms, and do not fail if it doesn't work.
+           * Don't use it on W32, because on W32 it will allow multiple
+           * bind to the same address:port, like SO_REUSEPORT on others. */
           if (0 > setsockopt (socket_fd,
                               SOL_SOCKET,
                               SO_REUSEADDR,
@@ -5003,6 +5006,7 @@ MHD_start_daemon_va (unsigned int flags,
                       MHD_socket_last_strerr_ ());
 #endif
           }
+#endif /* ! _WIN32 */
         }
       else if (daemon->listening_address_reuse > 0)
         {
diff --git a/src/microhttpd/internal.h b/src/microhttpd/internal.h
index 36ec6d8c..64f3c65c 100644
--- a/src/microhttpd/internal.h
+++ b/src/microhttpd/internal.h
@@ -1377,7 +1377,8 @@ struct MHD_Daemon
   /**
    * Whether to allow/disallow/ignore reuse of listening address.
    * The semantics is the following:
-   * 0: ignore (user did not ask for neither allow/disallow, use SO_REUSEADDR)
+   * 0: ignore (user did not ask for neither allow/disallow, use SO_REUSEADDR
+   *    except W32)
    * >0: allow (use SO_REUSEPORT on most platforms, SO_REUSEADDR on Windows)
    * <0: disallow (mostly no action, SO_EXCLUSIVEADDRUSE on Windows or SO_EXCLBIND
    *     on Solaris)