d8a59510c5
that if we sort the incoming SACK blocks, we can update the scoreboard in one pass of the scoreboard. The added overhead of sorting upto 4 sack blocks is much lower than traversing (potentially) large scoreboards multiple times. The code was updating the scoreboard with multiple passes over it (once for each sack option). The rewrite fixes that, reducing the complexity of the main loop from O(n^2) to O(n). Submitted by: Mohan Srinivasan, Noritoshi Demizu. Reviewed by: Raja Mukerji.
231 lines
7.8 KiB
C
231 lines
7.8 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp.h 8.1 (Berkeley) 6/10/93
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* $FreeBSD$
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*/
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#ifndef _NETINET_TCP_H_
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#define _NETINET_TCP_H_
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#include <sys/cdefs.h>
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#if __BSD_VISIBLE
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typedef u_int32_t tcp_seq;
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#define tcp6_seq tcp_seq /* for KAME src sync over BSD*'s */
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#define tcp6hdr tcphdr /* for KAME src sync over BSD*'s */
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/*
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* TCP header.
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* Per RFC 793, September, 1981.
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*/
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struct tcphdr {
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u_short th_sport; /* source port */
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u_short th_dport; /* destination port */
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tcp_seq th_seq; /* sequence number */
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tcp_seq th_ack; /* acknowledgement number */
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#if BYTE_ORDER == LITTLE_ENDIAN
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u_int th_x2:4, /* (unused) */
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th_off:4; /* data offset */
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#endif
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#if BYTE_ORDER == BIG_ENDIAN
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u_int th_off:4, /* data offset */
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th_x2:4; /* (unused) */
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#endif
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u_char th_flags;
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#define TH_FIN 0x01
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#define TH_SYN 0x02
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#define TH_RST 0x04
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#define TH_PUSH 0x08
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#define TH_ACK 0x10
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#define TH_URG 0x20
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#define TH_ECE 0x40
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#define TH_CWR 0x80
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#define TH_FLAGS (TH_FIN|TH_SYN|TH_RST|TH_ACK|TH_URG|TH_ECE|TH_CWR)
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u_short th_win; /* window */
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u_short th_sum; /* checksum */
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u_short th_urp; /* urgent pointer */
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};
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#define TCPOPT_EOL 0
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#define TCPOPT_NOP 1
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#define TCPOPT_MAXSEG 2
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#define TCPOLEN_MAXSEG 4
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#define TCPOPT_WINDOW 3
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#define TCPOLEN_WINDOW 3
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#define TCPOPT_SACK_PERMITTED 4 /* Experimental */
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#define TCPOLEN_SACK_PERMITTED 2
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#define TCPOPT_SACK 5 /* Experimental */
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#define TCPOLEN_SACK 8 /* 2*sizeof(tcp_seq) */
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#define TCPOPT_TIMESTAMP 8
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#define TCPOLEN_TIMESTAMP 10
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#define TCPOLEN_TSTAMP_APPA (TCPOLEN_TIMESTAMP+2) /* appendix A */
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#define TCPOPT_TSTAMP_HDR \
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(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_TIMESTAMP<<8|TCPOLEN_TIMESTAMP)
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#define MAX_TCPOPTLEN 40 /* Absolute maximum TCP options len */
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#define TCPOPT_SIGNATURE 19 /* Keyed MD5: RFC 2385 */
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#define TCPOLEN_SIGNATURE 18
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/* Option definitions */
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#define TCPOPT_SACK_PERMIT_HDR \
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(TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK_PERMITTED<<8|TCPOLEN_SACK_PERMITTED)
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#define TCPOPT_SACK_HDR (TCPOPT_NOP<<24|TCPOPT_NOP<<16|TCPOPT_SACK<<8)
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/* Miscellaneous constants */
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#define MAX_SACK_BLKS 6 /* Max # SACK blocks stored at sender side */
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#define TCP_MAX_SACK 4 /* MAX # SACKs sent in any segment */
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/*
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* Default maximum segment size for TCP.
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* With an IP MTU of 576, this is 536,
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* but 512 is probably more convenient.
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* This should be defined as MIN(512, IP_MSS - sizeof (struct tcpiphdr)).
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*/
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#define TCP_MSS 512
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/*
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* TCP_MINMSS is defined to be 216 which is fine for the smallest
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* link MTU (256 bytes, AX.25 packet radio) in the Internet.
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* However it is very unlikely to come across such low MTU interfaces
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* these days (anno dato 2003).
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* See tcp_subr.c tcp_minmss SYSCTL declaration for more comments.
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* Setting this to "0" disables the minmss check.
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*/
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#define TCP_MINMSS 216
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/*
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* TCP_MINMSSOVERLOAD is defined to be 1000 which should cover any type
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* of interactive TCP session.
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* See tcp_subr.c tcp_minmssoverload SYSCTL declaration and tcp_input.c
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* for more comments.
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* Setting this to "0" disables the minmssoverload check.
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*/
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#define TCP_MINMSSOVERLOAD 0 /* XXX: Disabled until refined */
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/*
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* Default maximum segment size for TCP6.
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* With an IP6 MSS of 1280, this is 1220,
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* but 1024 is probably more convenient. (xxx kazu in doubt)
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* This should be defined as MIN(1024, IP6_MSS - sizeof (struct tcpip6hdr))
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*/
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#define TCP6_MSS 1024
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#define TCP_MAXWIN 65535 /* largest value for (unscaled) window */
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#define TTCP_CLIENT_SND_WND 4096 /* dflt send window for T/TCP client */
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#define TCP_MAX_WINSHIFT 14 /* maximum window shift */
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#define TCP_MAXBURST 4 /* maximum segments in a burst */
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#define TCP_MAXHLEN (0xf<<2) /* max length of header in bytes */
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#define TCP_MAXOLEN (TCP_MAXHLEN - sizeof(struct tcphdr))
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/* max space left for options */
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#endif /* __BSD_VISIBLE */
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/*
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* User-settable options (used with setsockopt).
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*/
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#define TCP_NODELAY 0x01 /* don't delay send to coalesce packets */
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#if __BSD_VISIBLE
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#define TCP_MAXSEG 0x02 /* set maximum segment size */
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#define TCP_NOPUSH 0x04 /* don't push last block of write */
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#define TCP_NOOPT 0x08 /* don't use TCP options */
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#define TCP_MD5SIG 0x10 /* use MD5 digests (RFC2385) */
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#define TCP_INFO 0x20 /* retrieve tcp_info structure */
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#define TCPI_OPT_TIMESTAMPS 0x01
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#define TCPI_OPT_SACK 0x02
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#define TCPI_OPT_WSCALE 0x04
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#define TCPI_OPT_ECN 0x08
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/*
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* The TCP_INFO socket option comes from the Linux 2.6 TCP API, and permits
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* the caller to query certain information about the state of a TCP
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* connection. We provide an overlapping set of fields with the Linux
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* implementation, but since this is a fixed size structure, room has been
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* left for growth. In order to maximize potential future compatibility with
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* the Linux API, the same variable names and order have been adopted, and
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* padding left to make room for omitted fields in case they are added later.
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*
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* XXX: This is currently an unstable ABI/API, in that it is expected to
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* change.
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*/
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struct tcp_info {
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u_int8_t tcpi_state; /* TCP FSM state. */
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u_int8_t __tcpi_ca_state;
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u_int8_t __tcpi_retransmits;
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u_int8_t __tcpi_probes;
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u_int8_t __tcpi_backoff;
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u_int8_t tcpi_options; /* Options enabled on conn. */
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u_int8_t tcpi_snd_wscale:4, /* RFC1323 send shift value. */
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tcpi_rcv_wscale:4; /* RFC1323 recv shift value. */
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u_int32_t __tcpi_rto;
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u_int32_t __tcpi_ato;
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u_int32_t __tcpi_snd_mss;
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u_int32_t __tcpi_rcv_mss;
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u_int32_t __tcpi_unacked;
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u_int32_t __tcpi_sacked;
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u_int32_t __tcpi_lost;
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u_int32_t __tcpi_retrans;
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u_int32_t __tcpi_fackets;
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/* Times; measurements in usecs. */
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u_int32_t __tcpi_last_data_sent;
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u_int32_t __tcpi_last_ack_sent; /* Also unimpl. on Linux? */
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u_int32_t __tcpi_last_data_recv;
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u_int32_t __tcpi_last_ack_recv;
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/* Metrics; variable units. */
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u_int32_t __tcpi_pmtu;
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u_int32_t __tcpi_rcv_ssthresh;
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u_int32_t __tcpi_rtt;
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u_int32_t __tcpi_rttvar;
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u_int32_t tcpi_snd_ssthresh; /* Slow start threshold. */
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u_int32_t tcpi_snd_cwnd; /* Send congestion window. */
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u_int32_t __tcpi_advmss;
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u_int32_t __tcpi_reordering;
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u_int32_t __tcpi_rcv_rtt;
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u_int32_t tcpi_rcv_space; /* Advertised recv window. */
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/* FreeBSD extensions to tcp_info. */
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u_int32_t tcpi_snd_wnd; /* Advertised send window. */
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u_int32_t tcpi_snd_bwnd; /* Bandwidth send window. */
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/* Padding to grow without breaking ABI. */
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u_int32_t __tcpi_pad[32]; /* Padding. */
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};
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#endif
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#endif /* !_NETINET_TCP_H_ */
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