netinet/tcp: Add TCPOPT, TCPOLEN constants
Programs such as iptables depend on these constants, which can also
be found defined in other libcs.
Since only TCP_* is reserved as part of tcp.h's namespace, we hide
them behind _BSD_SOURCE (and therefore _DEFAULT_SOURCE) to expose
them by default, but keep it standard conforming.
diff --git a/include/netinet/tcp.h b/include/netinet/tcp.h
index 52358c7..f9b8464 100644
--- a/include/netinet/tcp.h
+++ b/include/netinet/tcp.h
@@ -41,7 +41,20 @@
#define TCP_CLOSING 11
#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#define TCPOPT_EOL 0
+#define TCPOPT_NOP 1
+#define TCPOPT_MAXSEG 2
+#define TCPOPT_WINDOW 3
+#define TCPOPT_SACK_PERMITTED 4
+#define TCPOPT_SACK 5
+#define TCPOPT_TIMESTAMP 8
+#define TCPOLEN_SACK_PERMITTED 2
+#define TCPOLEN_WINDOW 3
+#define TCPOLEN_MAXSEG 4
+#define TCPOLEN_TIMESTAMP 10
+
#define SOL_TCP 6
+
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>