Cygwin: tcp: Support TCP_FASTOPEN

TCP_FASTOPEN is supported since W10 1607.  Fake otherwise.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/fhandler.h

@@ -719,6 +719,7 @@ class fhandler_socket_inet: public fhandler_socket_wsock
 {
  private:
   bool oobinline;	/* True if option SO_OOBINLINE is set */
+  bool tcp_fastopen;	/* True if TCP_FASTOPEN is set on older systems */
  protected:
   int af_local_connect () { return 0; }
 

winsup/cygwin/fhandler_socket_inet.cc

@@ -691,7 +691,8 @@ fhandler_socket_wsock::set_socket_handle (SOCKET sock, int af, int type,
 
 fhandler_socket_inet::fhandler_socket_inet () :
   fhandler_socket_wsock (),
-  oobinline (false)
+  oobinline (false),
+  tcp_fastopen (false)
 {
 }
 
@@ -1693,6 +1694,20 @@ fhandler_socket_inet::setsockopt (int level, int optname, const void *optval,
 	  ignore = true;
 	  break;
 
+	case TCP_FASTOPEN:
+	  /* Fake FastOpen on older systems. */
+	  if (!wincap.has_tcp_fastopen ())
+	    {
+	      if (type != SOCK_STREAM)
+		{
+		  set_errno (EOPNOTSUPP);
+		  return -1;
+		}
+	      ignore = true;
+	      tcp_fastopen = *(int *) optval ? true : false;
+	    }
+	  break;
+
 	default:
 	  break;
 	}
@@ -1825,6 +1840,29 @@ fhandler_socket_inet::getsockopt (int level, int optname, const void *optval,
 	optname = convert_ws1_ip_optname (optname);
       break;
 
+    case IPPROTO_TCP:
+      switch (optname)
+	{
+	case TCP_FASTOPEN:
+	  /* Fake FastOpen on older systems */
+	  if (!wincap.has_tcp_fastopen ())
+	    {
+	      if (type != SOCK_STREAM)
+		{
+		  set_errno (EOPNOTSUPP);
+		  return -1;
+		}
+	      *(int *) optval = tcp_fastopen ? 1 : 0;
+	      *optlen = sizeof (int);
+	      return 0;
+	    }
+	  break;
+
+	default:
+	  break;
+	}
+      break;
+
     default:
       break;
     }
@@ -1869,6 +1907,10 @@ fhandler_socket_inet::getsockopt (int level, int optname, const void *optval,
 	  onebyte = true;
 	  break;
 
+	case TCP_FASTOPEN:
+	  onebyte = true;
+	  break;
+
 	default:
 	  break;
 	}
@@ -1881,8 +1923,7 @@ fhandler_socket_inet::getsockopt (int level, int optname, const void *optval,
       /* Regression in Vista and later: instead of a 4 byte BOOL value, a
 	 1 byte BOOLEAN value is returned, in contrast to older systems and
 	 the documentation.  Since an int type is expected by the calling
-	 application, we convert the result here.  For some reason only three
+	 application, we convert the result here. */
-	 BSD-compatible socket options seem to be affected. */
       BOOLEAN *in = (BOOLEAN *) optval;
       int *out = (int *) optval;
       *out = *in;

winsup/cygwin/include/netinet/tcp.h

@@ -125,5 +125,6 @@ struct tcphdr {
  */
 #define TCP_NODELAY     0x01    /* don't delay send to coalesce packets */
 #define TCP_MAXSEG      0x04    /* get maximum segment size (r/o on windows) */
+#define TCP_FASTOPEN    0x0f    /* enable FastOpen on listeners */
 
 #endif

winsup/cygwin/wincap.cc

@@ -46,6 +46,7 @@ wincaps wincap_vista __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:false,
   },
 };
 
@@ -77,6 +78,7 @@ wincaps wincap_7 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:false,
   },
 };
 
@@ -108,6 +110,7 @@ wincaps wincap_8 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:false,
   },
 };
 
@@ -139,6 +142,7 @@ wincaps wincap_8_1 __attribute__((section (".cygwin_dll_common"), shared)) = {
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:false,
   },
 };
 
@@ -170,6 +174,39 @@ wincaps  wincap_10_1507 __attribute__((section (".cygwin_dll_common"), shared))
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:false,
+  },
+};
+
+wincaps  wincap_10_1607 __attribute__((section (".cygwin_dll_common"), shared)) = {
+  def_guard_pages:2,
+  mmap_storage_high:0x700000000000LL,
+  {
+    is_server:false,
+    needs_count_in_si_lpres2:false,
+    needs_query_information:false,
+    has_gaa_largeaddress_bug:false,
+    has_broken_alloc_console:true,
+    has_console_logon_sid:true,
+    has_precise_system_time:true,
+    has_microsoft_accounts:true,
+    has_processor_groups:true,
+    has_broken_prefetchvm:true,
+    has_new_pebteb_region:false,
+    has_broken_whoami:false,
+    has_unprivileged_createsymlink:false,
+    has_unbiased_interrupt_time:true,
+    has_precise_interrupt_time:true,
+    has_posix_unlink_semantics:false,
+    has_case_sensitive_dirs:false,
+    has_posix_rename_semantics:false,
+    no_msv1_0_s4u_logon_in_wow64:false,
+    has_con_24bit_colors:false,
+    has_con_broken_csi3j:false,
+    has_con_broken_il_dl:false,
+    has_con_esc_rep:false,
+    has_extended_mem_api:false,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -201,6 +238,7 @@ wincaps wincap_10_1703 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -232,6 +270,7 @@ wincaps wincap_10_1709 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:false,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -263,6 +302,7 @@ wincaps wincap_10_1803 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:true,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -294,6 +334,7 @@ wincaps wincap_10_1809 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_con_broken_il_dl:false,
     has_con_esc_rep:false,
     has_extended_mem_api:true,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -325,6 +366,7 @@ wincaps wincap_10_1903 __attribute__((section (".cygwin_dll_common"), shared)) =
     has_con_broken_il_dl:true,
     has_con_esc_rep:true,
     has_extended_mem_api:true,
+    has_tcp_fastopen:true,
   },
 };
 
@@ -378,6 +420,8 @@ wincapc::init ()
 	  caps = &wincap_10_1709;
 	else if (version.dwBuildNumber >= 15063)
 	  caps = &wincap_10_1703;
+	else if (version.dwBuildNumber >= 14393)
+	  caps = &wincap_10_1607;
 	else
 	  caps = & wincap_10_1507;
     }

winsup/cygwin/wincap.h

@@ -40,6 +40,7 @@ struct wincaps
     unsigned has_con_broken_il_dl		: 1;
     unsigned has_con_esc_rep			: 1;
     unsigned has_extended_mem_api		: 1;
+    unsigned has_tcp_fastopen			: 1;
   };
 };
 
@@ -103,6 +104,7 @@ public:
   bool	IMPLEMENT (has_con_broken_il_dl)
   bool	IMPLEMENT (has_con_esc_rep)
   bool	IMPLEMENT (has_extended_mem_api)
+  bool	IMPLEMENT (has_tcp_fastopen)
 
   void disable_case_sensitive_dirs ()
   {