diff --git a/StdLib/Include/netinet/tcp.h b/StdLib/Include/netinet/tcp.h
new file mode 100644
index 0000000000..8bb8f61ec9
--- /dev/null
+++ b/StdLib/Include/netinet/tcp.h
@@ -0,0 +1,132 @@
+/*	$NetBSD: tcp.h,v 1.28 2007/12/25 18:33:47 perry Exp $	*/
+
+/*
+ * Copyright (c) 1982, 1986, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)tcp.h	8.1 (Berkeley) 6/10/93
+ */
+
+#ifndef _NETINET_TCP_H_
+#define _NETINET_TCP_H_
+
+#include <sys/featuretest.h>
+
+#if defined(_NETBSD_SOURCE)
+
+typedef u_int32_t tcp_seq;
+/*
+ * TCP header.
+ * Per RFC 793, September, 1981.
+ * Updated by RFC 3168, September, 2001.
+ */
+struct tcphdr {
+	u_int16_t th_sport;		/* source port */
+	u_int16_t th_dport;		/* destination port */
+	tcp_seq	  th_seq;		/* sequence number */
+	tcp_seq	  th_ack;		/* acknowledgement number */
+#if BYTE_ORDER == LITTLE_ENDIAN
+	/*LINTED non-portable bitfields*/
+	u_int8_t  th_x2:4,		/* (unused) */
+		  th_off:4;		/* data offset */
+#endif
+#if BYTE_ORDER == BIG_ENDIAN
+	/*LINTED non-portable bitfields*/
+	u_int8_t  th_off:4,		/* data offset */
+		  th_x2:4;		/* (unused) */
+#endif
+	u_int8_t  th_flags;
+#define	TH_FIN	  0x01
+#define	TH_SYN	  0x02
+#define	TH_RST	  0x04
+#define	TH_PUSH	  0x08
+#define	TH_ACK	  0x10
+#define	TH_URG	  0x20
+#define	TH_ECE	  0x40
+#define	TH_CWR	  0x80
+	u_int16_t th_win;			/* window */
+	u_int16_t th_sum;			/* checksum */
+	u_int16_t th_urp;			/* urgent pointer */
+} __packed;
+
+#define	TCPOPT_EOL		0
+#define	TCPOPT_NOP		1
+#define	TCPOPT_MAXSEG		2
+#define	   TCPOLEN_MAXSEG		4
+#define	TCPOPT_WINDOW		3
+#define	   TCPOLEN_WINDOW		3
+#define	TCPOPT_SACK_PERMITTED	4		/* Experimental */
+#define	   TCPOLEN_SACK_PERMITTED	2
+#define	TCPOPT_SACK		5		/* Experimental */
+#define	TCPOPT_TIMESTAMP	8
+#define	   TCPOLEN_TIMESTAMP		10
+#define	   TCPOLEN_TSTAMP_APPA		(TCPOLEN_TIMESTAMP+2) /* appendix A */
+
+#define TCPOPT_TSTAMP_HDR	\
+    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
+
+#define	TCPOPT_SIGNATURE	19		/* Keyed MD5: RFC 2385 */
+#define	   TCPOLEN_SIGNATURE		18
+#define    TCPOLEN_SIGLEN		(TCPOLEN_SIGNATURE+2) /* padding */
+
+#define MAX_TCPOPTLEN	40	/* max # bytes that go in options */
+
+/*
+ * Default maximum segment size for TCP.
+ * This is defined by RFC 1112 Sec 4.2.2.6.
+ */
+#define	TCP_MSS		536
+
+#define	TCP_MINMSS	216
+
+#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
+
+#define	TCP_MAX_WINSHIFT	14	/* maximum window shift */
+
+#define	TCP_MAXBURST	4	/* maximum segments in a burst */
+
+#endif /* _NETBSD_SOURCE */
+
+/*
+ * User-settable options (used with setsockopt).
+ */
+#define	TCP_NODELAY	1	/* don't delay send to coalesce packets */
+#define	TCP_MAXSEG	2	/* set maximum segment size */
+#define	TCP_KEEPIDLE	3
+#ifdef notyet
+#define	TCP_NOPUSH	4	/* reserved for FreeBSD compat */
+#endif
+#define	TCP_KEEPINTVL	5
+#define	TCP_KEEPCNT	6
+#define	TCP_KEEPINIT	7
+#ifdef notyet
+#define	TCP_NOOPT	8	/* reserved for FreeBSD compat */
+#endif
+#define	TCP_MD5SIG	0x10	/* use MD5 digests (RFC2385) */
+#define	TCP_CONGCTL	0x20	/* selected congestion control */
+
+#endif /* !_NETINET_TCP_H_ */