xnu-3789.70.16.tar.gz

[apple/xnu.git] / bsd / netinet / tcp.h

/*
 * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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 * Please see the License for the specific language governing rights and
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 *
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 */
/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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
 * $FreeBSD: src/sys/netinet/tcp.h,v 1.13.2.3 2001/03/01 22:08:42 jlemon Exp $
 */

#ifndef _NETINET_TCP_H_
#define _NETINET_TCP_H_
#include <sys/types.h>
#include <sys/appleapiopts.h>
#include <machine/endian.h>

#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
typedef	__uint32_t tcp_seq;
typedef __uint32_t tcp_cc;		/* connection count per rfc1644 */

#define tcp6_seq	tcp_seq	/* for KAME src sync over BSD*'s */
#define tcp6hdr		tcphdr	/* for KAME src sync over BSD*'s */

/*
 * TCP header.
 * Per RFC 793, September, 1981.
 */
struct tcphdr {
	unsigned short	th_sport;	/* source port */
	unsigned short	th_dport;	/* destination port */
	tcp_seq	th_seq;			/* sequence number */
	tcp_seq	th_ack;			/* acknowledgement number */
#if __DARWIN_BYTE_ORDER == __DARWIN_LITTLE_ENDIAN
	unsigned int	th_x2:4,	/* (unused) */
			th_off:4;	/* data offset */
#endif
#if __DARWIN_BYTE_ORDER == __DARWIN_BIG_ENDIAN
	unsigned int	th_off:4,	/* data offset */
			th_x2:4;	/* (unused) */
#endif
	unsigned char	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
#define	TH_FLAGS	(TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)

	unsigned short	th_win;		/* window */
	unsigned short	th_sum;		/* checksum */
	unsigned short	th_urp;		/* urgent pointer */
};

#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 TCPOLEN_SACK		8		/* len of sack block */
#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	MAX_TCPOPTLEN		40	/* Absolute maximum TCP options len */

#define	TCPOPT_CC		11		/* CC options: RFC-1644 */
#define TCPOPT_CCNEW		12
#define TCPOPT_CCECHO		13
#define	   TCPOLEN_CC			6
#define	   TCPOLEN_CC_APPA		(TCPOLEN_CC+2)
#define	   TCPOPT_CC_HDR(ccopt)		\
    (TCPOPT_NOP<<24|TCPOPT_NOP<<16|(ccopt)<<8|TCPOLEN_CC)
#define	TCPOPT_SIGNATURE		19	/* Keyed MD5: RFC 2385 */
#define	   TCPOLEN_SIGNATURE		18
#if MPTCP
#define	TCPOPT_MULTIPATH  		30
#endif

#define	TCPOPT_FASTOPEN			34
#define	TCPOLEN_FASTOPEN_REQ		2

/* Option definitions */
#define TCPOPT_SACK_PERMIT_HDR	\
(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
#define	TCPOPT_SACK_HDR		(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
/* Miscellaneous constants */
#define	MAX_SACK_BLKS	6	/* Max # SACK blocks stored at sender side */

/*
 * A SACK option that specifies n blocks will have a length of (8*n + 2)
 * bytes, so the 40 bytes available for TCP options can specify a
 * maximum of 4 blocks.
 */

#define	TCP_MAX_SACK	4	/* MAX # SACKs sent in any segment */


/*
 * Default maximum segment size for TCP.
 * With an IP MTU of 576, this is 536,
 * but 512 is probably more convenient.
 * This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
 */
#define	TCP_MSS	512

/*
 * TCP_MINMSS is defined to be 216 which is fine for the smallest
 * link MTU (256 bytes, SLIP interface) in the Internet.
 * However it is very unlikely to come across such low MTU interfaces
 * these days (anno dato 2004).
 * Probably it can be set to 512 without ill effects. But we play safe.
 * See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
 * Setting this to "0" disables the minmss check.
 */
#define	TCP_MINMSS 216

/*
 * Default maximum segment size for TCP6.
 * With an IP6 MSS of 1280, this is 1220,
 * but 1024 is probably more convenient. (xxx kazu in doubt)
 * This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
 */
#define	TCP6_MSS	1024

#define	TCP_MAXWIN	65535	/* largest value for (unscaled) window */
#define	TTCP_CLIENT_SND_WND	4096	/* dflt send window for T/TCP client */

#define TCP_MAX_WINSHIFT	14	/* maximum window shift */

#define TCP_MAXHLEN	(0xf<<2)	/* max length of header in bytes */
#define TCP_MAXOLEN	(TCP_MAXHLEN - sizeof(struct tcphdr))
					/* max space left for options */
#endif /* (_POSIX_C_SOURCE && !_DARWIN_C_SOURCE) */

/*
 * User-settable options (used with setsockopt).
 */
#define	TCP_NODELAY             0x01    /* don't delay send to coalesce packets */
#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)
#define	TCP_MAXSEG              0x02    /* set maximum segment size */
#define TCP_NOPUSH              0x04    /* don't push last block of write */
#define TCP_NOOPT               0x08    /* don't use TCP options */
#define TCP_KEEPALIVE           0x10    /* idle time used when SO_KEEPALIVE is enabled */
#define TCP_CONNECTIONTIMEOUT   0x20    /* connection timeout */
#define PERSIST_TIMEOUT		0x40	/* time after which a connection in
					 *  persist timeout will terminate.
					 *  see draft-ananth-tcpm-persist-02.txt
					 */
#define TCP_RXT_CONNDROPTIME	0x80	/* time after which tcp retransmissions will be 
					 * stopped and the connection will be dropped
					 */
#define TCP_RXT_FINDROP		0x100	/* when this option is set, drop a connection 
					 * after retransmitting the FIN 3 times. It will
					 * prevent holding too many mbufs in socket 
					 * buffer queues.
					 */
#define	TCP_KEEPINTVL		0x101	/* interval between keepalives */
#define	TCP_KEEPCNT		0x102	/* number of keepalives before close */
#define	TCP_SENDMOREACKS	0x103	/* always ack every other packet */
#define	TCP_ENABLE_ECN		0x104	/* Enable ECN on a connection */
#define	TCP_FASTOPEN		0x105	/* Enable/Disable TCP Fastopen on this socket */
#define	TCP_CONNECTION_INFO	0x106	/* State of TCP connection */

#ifdef PRIVATE
#define	TCP_INFO		0x200	/* retrieve tcp_info structure */
#define TCP_MEASURE_SND_BW	0x202	/* Measure sender's bandwidth for this connection */
#endif /* PRIVATE */


#define	TCP_NOTSENT_LOWAT	0x201	/* Low water mark for TCP unsent data */

#ifdef PRIVATE
#define TCP_MEASURE_BW_BURST	0x203	/* Burst size to use for bandwidth measurement */
#define TCP_PEER_PID		0x204	/* Lookup pid of the process we're connected to */
#define TCP_ADAPTIVE_READ_TIMEOUT	0x205	/* Read timeout used as a multiple of RTT */	
/*
 * Enable message delivery on a socket, this feature is currently unsupported and
 * is subjected to change in future.
 */
#define	TCP_ENABLE_MSGS			0x206
#define	TCP_ADAPTIVE_WRITE_TIMEOUT	0x207	/* Write timeout used as a multiple of RTT */
#define	TCP_NOTIMEWAIT			0x208	/* Avoid going into time-wait */
#define	TCP_DISABLE_BLACKHOLE_DETECTION	0x209	/* disable PMTU blackhole detection */
#define	TCP_ECN_MODE			0x210	/* fine grain control for A/B testing */
#define	TCP_KEEPALIVE_OFFLOAD		0x211	/* offload keep alive processing to firmware */

/*
 * TCP_ECN_MODE values
 */
#define	ECN_MODE_DEFAULT		0x0	/* per interface or system wide default */
#define	ECN_MODE_ENABLE			0x1	/* force enable ECN on connection */
#define	ECN_MODE_DISABLE		0x2	/* force disable ECN on connection */

/*
 * TCP_NOTIFY_ACKNOWLEDGEMENT
 *
 * Application can use this socket option to get a notification when
 * data that is currently written to the socket is acknowledged. The input
 * argument given to this socket option is a marker_id that will be used for
 * returning the notification. The application can continue to write
 * data after setting the marker. There can be multiple of these events
 * outstanding on a socket at any time up to a max of TCP_MAX_NOTIFY_ACK.
 *
 * To get the completed notifications, getsockopt should be called with the
 * TCP_NOTIFY_ACKNOWLEDGEMENT with the following tcp_notify_ack_complete
 * structure as an out argument. At most TCP_MAX_NOTIFY_ACK ids will be
 * returned if they have been successfully acknowledged in each call.
 */

#define TCP_MAX_NOTIFY_ACK	10

typedef	u_int32_t	tcp_notify_ack_id_t;

struct tcp_notify_ack_complete {
	u_int32_t	notify_pending;	/* still pending */
	u_int32_t	notify_complete_count;
	tcp_notify_ack_id_t notify_complete_id[TCP_MAX_NOTIFY_ACK];
};

#define	TCP_NOTIFY_ACKNOWLEDGEMENT	0x212	/* Notify when data is acknowledged */

/*
 * The TCP_INFO socket option is a private API and is subject to change
 */
#pragma pack(4)

#define	TCPI_OPT_TIMESTAMPS	0x01
#define	TCPI_OPT_SACK		0x02
#define	TCPI_OPT_WSCALE		0x04
#define	TCPI_OPT_ECN		0x08

#define TCPI_FLAG_LOSSRECOVERY	0x01	/* Currently in loss recovery */
#define	TCPI_FLAG_STREAMING_ON	0x02	/* Streaming detection on */

struct tcp_conn_status {
	unsigned int	probe_activated : 1;
	unsigned int	write_probe_failed : 1;
	unsigned int	read_probe_failed : 1;
	unsigned int	conn_probe_failed : 1;
};

/*
 * Add new fields to this structure at the end only. This will preserve
 * binary compatibility.
 */
struct tcp_info {
	u_int8_t	tcpi_state;			/* TCP FSM state. */
	u_int8_t	tcpi_options;		/* Options enabled on conn. */
	u_int8_t	tcpi_snd_wscale;	/* RFC1323 send shift value. */
	u_int8_t	tcpi_rcv_wscale;	/* RFC1323 recv shift value. */

	u_int32_t	tcpi_flags;			/* extra flags (TCPI_FLAG_xxx) */

	u_int32_t	tcpi_rto;			/* Retransmission timeout in milliseconds */
	u_int32_t	tcpi_snd_mss;		/* Max segment size for send. */
	u_int32_t	tcpi_rcv_mss;		/* Max segment size for receive. */

	u_int32_t	tcpi_rttcur;		/* Most recent value of RTT */
	u_int32_t	tcpi_srtt;			/* Smoothed RTT */
	u_int32_t	tcpi_rttvar;		/* RTT variance */
	u_int32_t	tcpi_rttbest;		/* Best RTT we've seen */

	u_int32_t	tcpi_snd_ssthresh;	/* Slow start threshold. */
	u_int32_t	tcpi_snd_cwnd;		/* Send congestion window. */

	u_int32_t	tcpi_rcv_space;		/* Advertised recv window. */

	u_int32_t	tcpi_snd_wnd;		/* Advertised send window. */
	u_int32_t	tcpi_snd_nxt;		/* Next egress seqno */
	u_int32_t	tcpi_rcv_nxt;		/* Next ingress seqno */

	int32_t		tcpi_last_outif;	/* if_index of interface used to send last */
	u_int32_t	tcpi_snd_sbbytes;	/* bytes in snd buffer including data inflight */

	u_int64_t	tcpi_txpackets __attribute__((aligned(8)));	/* total packets sent */
	u_int64_t	tcpi_txbytes __attribute__((aligned(8)));
									/* total bytes sent */	
	u_int64_t	tcpi_txretransmitbytes __attribute__((aligned(8)));
									/* total bytes retransmitted */	
	u_int64_t	tcpi_txunacked __attribute__((aligned(8)));
									/* current number of bytes not acknowledged */	
	u_int64_t	tcpi_rxpackets __attribute__((aligned(8)));	/* total packets received */
	u_int64_t	tcpi_rxbytes __attribute__((aligned(8)));
									/* total bytes received */
	u_int64_t	tcpi_rxduplicatebytes __attribute__((aligned(8)));
									/* total duplicate bytes received */
	u_int64_t	tcpi_rxoutoforderbytes __attribute__((aligned(8)));
									/* total out of order bytes received */
	u_int64_t	tcpi_snd_bw __attribute__((aligned(8)));	/* measured send bandwidth in bits/sec */
	u_int8_t	tcpi_synrexmits;	/* Number of syn retransmits before connect */
	u_int8_t	tcpi_unused1;
	u_int16_t	tcpi_unused2;
	u_int64_t	tcpi_cell_rxpackets __attribute((aligned(8)));	/* packets received over cellular */
	u_int64_t	tcpi_cell_rxbytes __attribute((aligned(8)));	/* bytes received over cellular */
	u_int64_t	tcpi_cell_txpackets __attribute((aligned(8)));	/* packets transmitted over cellular */
	u_int64_t	tcpi_cell_txbytes __attribute((aligned(8)));	/* bytes transmitted over cellular */
	u_int64_t	tcpi_wifi_rxpackets __attribute((aligned(8)));	/* packets received over Wi-Fi */
	u_int64_t	tcpi_wifi_rxbytes __attribute((aligned(8)));	/* bytes received over Wi-Fi */
	u_int64_t	tcpi_wifi_txpackets __attribute((aligned(8)));	/* packets transmitted over Wi-Fi */
	u_int64_t	tcpi_wifi_txbytes __attribute((aligned(8)));	/* bytes transmitted over Wi-Fi */
	u_int64_t	tcpi_wired_rxpackets __attribute((aligned(8)));	/* packets received over Wired */
	u_int64_t	tcpi_wired_rxbytes __attribute((aligned(8)));	/* bytes received over Wired */
	u_int64_t	tcpi_wired_txpackets __attribute((aligned(8)));	/* packets transmitted over Wired */
	u_int64_t	tcpi_wired_txbytes __attribute((aligned(8)));	/* bytes transmitted over Wired */
	struct tcp_conn_status	tcpi_connstatus; /* status of connection probes */

	u_int16_t
		tcpi_tfo_cookie_req:1, /* Cookie requested? */
		tcpi_tfo_cookie_rcv:1, /* Cookie received? */
		tcpi_tfo_syn_loss:1,   /* Fallback to reg. TCP after SYN-loss */
		tcpi_tfo_syn_data_sent:1, /* SYN+data has been sent out */
		tcpi_tfo_syn_data_acked:1, /* SYN+data has been fully acknowledged */
		tcpi_tfo_syn_data_rcv:1, /* Server received SYN+data with a valid cookie */
		tcpi_tfo_cookie_req_rcv:1, /* Server received cookie-request */
		tcpi_tfo_cookie_sent:1, /* Server announced cookie */
		tcpi_tfo_cookie_invalid:1, /* Server received an invalid cookie */
		tcpi_tfo_cookie_wrong:1, /* Our sent cookie was wrong */
		tcpi_tfo_no_cookie_rcv:1, /* We did not receive a cookie upon our request */
		tcpi_tfo_heuristics_disable:1, /* TFO-heuristics disabled it */
		tcpi_tfo_send_blackhole:1, /* A sending-blackhole got detected */
		tcpi_tfo_recv_blackhole:1; /* A receiver-blackhole got detected */

	u_int16_t	tcpi_ecn_client_setup:1,	/* Attempted ECN setup from client side */
			tcpi_ecn_server_setup:1,	/* Attempted ECN setup from server side */
			tcpi_ecn_success:1,		/* peer negotiated ECN */
			tcpi_ecn_lost_syn:1,		/* Lost SYN with ECN setup */
			tcpi_ecn_lost_synack:1,		/* Lost SYN-ACK with ECN setup */
			tcpi_local_peer:1,		/* Local to the host or the subnet */
			tcpi_if_cell:1,			/* Interface is cellular */
			tcpi_if_wifi:1;			/* Interface is WiFi */

	u_int32_t	tcpi_ecn_recv_ce;	/* Packets received with CE */
	u_int32_t	tcpi_ecn_recv_cwr;	/* Packets received with CWR */

	u_int32_t	tcpi_rcvoopack;		/* out-of-order packets received */
	u_int32_t	tcpi_pawsdrop;		/* segments dropped due to PAWS */
	u_int32_t	tcpi_sack_recovery_episode; /* SACK recovery episodes */
	u_int32_t	tcpi_reordered_pkts;	/* packets reorderd */
	u_int32_t	tcpi_dsack_sent;	/* Sent DSACK notification */
	u_int32_t	tcpi_dsack_recvd;	/* Received a valid DSACK option */
	u_int32_t	tcpi_flowhash;		/* Unique id for the connection */

	u_int64_t	tcpi_txretransmitpackets __attribute__((aligned(8)));
};

struct tcp_measure_bw_burst {
	u_int32_t	min_burst_size; /* Minimum number of packets to use */
	u_int32_t	max_burst_size; /* Maximum number of packets to use */
};

/*
 * Note that IPv6 link local addresses should have the appropriate scope ID
 */

struct info_tuple {
	u_int8_t	itpl_proto;
	union {
		struct sockaddr		_itpl_sa;
		struct sockaddr_in	_itpl_sin;
		struct sockaddr_in6	_itpl_sin6;
	} itpl_localaddr;
	union {
		struct sockaddr		_itpl_sa;
		struct sockaddr_in	_itpl_sin;
		struct sockaddr_in6	_itpl_sin6;
	} itpl_remoteaddr;
};

#define itpl_local_sa		itpl_localaddr._itpl_sa
#define itpl_local_sin 		itpl_localaddr._itpl_sin
#define itpl_local_sin6		itpl_localaddr._itpl_sin6
#define itpl_remote_sa 		itpl_remoteaddr._itpl_sa
#define itpl_remote_sin		itpl_remoteaddr._itpl_sin
#define itpl_remote_sin6	itpl_remoteaddr._itpl_sin6

/*
 * TCP connection info auxiliary data (CIAUX_TCP)
 *
 * Do not add new fields to this structure, just add them to tcp_info 
 * structure towards the end. This will preserve binary compatibility.
 */
typedef struct conninfo_tcp {
	pid_t			tcpci_peer_pid;	/* loopback peer PID if > 0 */
	struct tcp_info		tcpci_tcp_info;	/* TCP info */
} conninfo_tcp_t;

#pragma pack()

#endif /* PRIVATE */

struct tcp_connection_info {
        u_int8_t	tcpi_state;     /* connection state */
        u_int8_t	tcpi_snd_wscale; /* Window scale for send window */
        u_int8_t	tcpi_rcv_wscale; /* Window scale for receive window */
        u_int8_t	__pad1;
        u_int32_t	tcpi_options;   /* TCP options supported */
#define TCPCI_OPT_TIMESTAMPS	0x00000001 /* Timestamps enabled */
#define TCPCI_OPT_SACK		0x00000002 /* SACK enabled */
#define TCPCI_OPT_WSCALE	0x00000004 /* Window scaling enabled */
#define TCPCI_OPT_ECN		0x00000008 /* ECN enabled */
        u_int32_t	tcpi_flags;     /* flags */
#define TCPCI_FLAG_LOSSRECOVERY 0x00000001
#define TCPCI_FLAG_REORDERING_DETECTED  0x00000002
        u_int32_t	tcpi_rto;       /* retransmit timeout in ms */
        u_int32_t	tcpi_maxseg;    /* maximum segment size supported */
        u_int32_t	tcpi_snd_ssthresh; /* slow start threshold in bytes */
        u_int32_t	tcpi_snd_cwnd;  /* send congestion window in bytes */
        u_int32_t	tcpi_snd_wnd;   /* send widnow in bytes */
        u_int32_t	tcpi_snd_sbbytes; /* bytes in send socket buffer, including in-flight data */
        u_int32_t	tcpi_rcv_wnd;   /* receive window in bytes*/
        u_int32_t	tcpi_rttcur;    /* most recent RTT in ms */
        u_int32_t	tcpi_srtt;      /* average RTT in ms */
        u_int32_t	tcpi_rttvar;    /* RTT variance */
	u_int32_t
			tcpi_tfo_cookie_req:1, /* Cookie requested? */
			tcpi_tfo_cookie_rcv:1, /* Cookie received? */
			tcpi_tfo_syn_loss:1,   /* Fallback to reg. TCP after SYN-loss */
			tcpi_tfo_syn_data_sent:1, /* SYN+data has been sent out */
			tcpi_tfo_syn_data_acked:1, /* SYN+data has been fully acknowledged */
			tcpi_tfo_syn_data_rcv:1, /* Server received SYN+data with a valid cookie */
			tcpi_tfo_cookie_req_rcv:1, /* Server received cookie-request */
			tcpi_tfo_cookie_sent:1, /* Server announced cookie */
			tcpi_tfo_cookie_invalid:1, /* Server received an invalid cookie */
			tcpi_tfo_cookie_wrong:1, /* Our sent cookie was wrong */
			tcpi_tfo_no_cookie_rcv:1, /* We did not receive a cookie upon our request */
			tcpi_tfo_heuristics_disable:1, /* TFO-heuristics disabled it */
			tcpi_tfo_send_blackhole:1, /* A sending-blackhole got detected */
			tcpi_tfo_recv_blackhole:1, /* A receiver-blackhole got detected */
			__pad2:18;
        u_int64_t	tcpi_txpackets __attribute__((aligned(8)));
        u_int64_t	tcpi_txbytes __attribute__((aligned(8)));
        u_int64_t	tcpi_txretransmitbytes __attribute__((aligned(8)));
        u_int64_t	tcpi_rxpackets __attribute__((aligned(8)));
        u_int64_t	tcpi_rxbytes __attribute__((aligned(8)));
        u_int64_t	tcpi_rxoutoforderbytes __attribute__((aligned(8)));
        u_int64_t	tcpi_txretransmitpackets __attribute__((aligned(8)));
};
#endif /* (_POSIX_C_SOURCE && !_DARWIN_C_SOURCE) */

#endif