text: /*
   * 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
   * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
   * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
   * Please see the License for the specific language governing rights and
   * limitations under the License.
   *
   * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
   */
  /*
   * 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>
  #include <machine/types.h> /* __uint32_t */
  
  #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 */
  
  
  
  #define	TCP_NOTSENT_LOWAT	0x201	/* Low water mark for TCP unsent data */
  
  
  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 */
  			tcpi_tfo_onebyte_proxy:1, /* A proxy acknowledges all but one byte of the SYN */
  			__pad2:17;
          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
  