.\" This man page is Copyright (C) 1999 Andi Kleen <ak@muc.de>.
.\" Permission is granted to distribute possibly modified copies
.\" of this page provided the header is included verbatim,
.\" and in case of nontrivial modification author and date
.\" of the modification is added to the header.
.\"
.\" 2.4 Updates by Nivedita Singhvi 4/20/02 <nivedita@us.ibm.com>.
.\" Modified, 2004-11-11, Michael Kerrisk and Andries Brouwer
.\"	Updated details of interaction of TCP_CORK and TCP_NODELAY.
.\"
.\" FIXME 2.6.17-rc1 adds the following /proc files, which need to be
.\" 	  documented: tcp_mtu_probing, tcp_base_mss, and
.\"	  tcp_workaround_signed_windows
.\"
.\" Japanese Version Copyright (c) 1999 NAKANO Takeo all rights reserved.
.\" Translated 1999-12-06, NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated 2002-11-15, NAKANO Takeo
.\" Updated 2005-02-21, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-09-07, Akihiro MOTOKI
.\" Updated 2005-12-26, Akihiro MOTOKI
.\" Updated 2006-07-19, Akihiro MOTOKI, Catch up to LDP v2.36
.\"
.\"WORD         full duplex connection  ̿
.\"WORD         listening state         ³Ԥ
.\"WORD         denial of service attack	DoS 
.\"WORD         urgent data             ۵ޥǡ
.\"
.TH TCP  7 2007-11-25 "Linux" "Linux Programmer's Manual"
.SH ̾
tcp \- TCP ץȥ
.SH 
.B #include <sys/socket.h>
.br
.B #include <netinet/in.h>
.br
.B #include <netinet/tcp.h>
.sp
.B tcp_socket = socket(PF_INET, SOCK_STREAM, 0);
.SH 
 RFC\ 793, RFC\ 1122, RFC\ 2001 Ƥ TCP ץȥ
NewReno ĥ SACK ĥޤƼΤǤ롣
TCP ϡ
.BR ip (7)
ĤΥåȴ֤ˡι⤤ȥ꡼ظ
(full-duplex) ̿󶡤롣
v4  v6 ξΥС
.BR ip (7)
бƤ롣
TCP ϡǡä夹뤳ȡǼ줿ѥåȤ
뤳Ȥݾڤ롣ޤѥåñ̤˥å
뤳Ȥǡž顼Τ롣
TCP ϥ쥳ɶ (record boundary) ¸ʤ

줿Ф TCP åȤϡ
⡼ȥɥ쥹륢ɥ쥹ʤ
äƾܺ٤˻ꤵ줿֤ǤϤʤ
ؤ TCP ³ˤϡ
.BR connect (2)
ѤƤ⤦ TCP åȤؤ³Ω롣
ο³ˤϡޤ
.BR bind (2)
ǥåȤʥɥ쥹ȥݡȤ˷ӤĤ
.BR listen (2)
ƤǥåȤ³Ԥ֤ˤ롣
θ塢夷³׵Ф
.BR accept (2)
ѤåȤ򿷤롣
.BR accept (2)
ޤ
.BR connect (2)
Υ뤬åȤϡܺ٤˻ꤵ줿֤Ȥʤꡢ
ǡΤȤ꤬ǽȤʤ롣³Ԥ֤ (listening) åȤ䡢
³ (connect) ƤʤåȤ̤ƥǡȤꤹ뤳ȤϤǤʤ

Linux  RFC\ 1323  TCP high performance ĥ򥵥ݡȤƤ롣
ˤϡProtection Against Wrapped Sequence Numbers (PAWS)
ɥ󥰡ॹפʤɤޤޤƤ롣
ɥ󥰤ѤȡٱޤӰ礭³ǡ
(64K ʾ)  TCP ɥѤ뤳ȤǽȤʤ롣
ѤˤϡΥХåե礭ʤФʤʤ
Хåե sysctl ѿ
.I net.ipv4.tcp_wmem

.I net.ipv4.tcp_rmem
ѤơƥΤ礭Ǥ롣
뤤ϡġΥåȤΤߤ礭ˤϡ
.B SO_SNDBUF

.B SO_RCVBUF
åȥץѤ
.BR setsockopt (2)
ѤꤹФ褤

.B SO_SNDBUF

.B SO_RCVBUF
Υᥫ˥륽åȥХåեκ祵ϡ
.I net.core.rmem_max

.I net.core.wmem_max
sysctl ǻꤵ줿ƥȤƤͤĶ뤳ȤϤǤʤ
TCP ϼºݤˤ
.BR setsockopt (2)
뤬׵ᤷХåեܤƤ롣
Τᡢθ
.BR getsockopt (2)
Ԥȡ
.BR setsockopt (2)
׵ᤷХåեȤϰۤʤ֤ͤ롣
TCP Ϥ;ʬʶ֤򡢴Ū䥫ͥι¤ΤѤƤꡢ
sysctl ѿϼºݤ TCP ɥ礭ʥȿǤ롣
³ˤ륽åȤΥХåեѹͭˤˤϡ
.BR listen (2)

.BR connect (2)
ꤷʤФʤʤ
ܤ
.BR socket (7)
򸫤衣
.PP
TCP ϶۵ޥǡ (urgent data) 򥵥ݡȤƤ롣۵ޥǡ
餫νפʥåǡȥ꡼˴ޤޤƤ뤳ȡ
ΥǡǤ᤯٤ȡԤ뤿Ѥ롣
۵ޥǡˤϡ
.BR send (2)

.B MSG_OOB
ץꤹ롣
۵ޥǡȡͥ
.B SIGURG
ʥ롣
.B SIOCSPGRP

.B FIOSETOWN
ioctl ( POSIX.1-2001 ǵꤵƤ
.BR fcntl (2)
.B F_SETOWN
) ѤƤΥåȤΡֽͭԡפȤꤵ줿
ץץ롼פǤ롣
.B SO_OOBINLINE
åȥץͭˤʤäƤȡ۵ޥǡ
̾Υǡȥ꡼˺ (ץϲ
.B SIOCATMARK
ioctl Ȥäƶ۵ޥǡξĴ٤뤳ȤǤ)
̵ˤʤäƤˤϡ
.BR recv (2)

.BR recvmsg (2)

.B MSG_OOB
ե饰åȤƤȤˤΤߡ۵ޥǡǤ롣

Linux 2.4 Ǥ¿ѹʤ졢
롼ץåȤȥ󥰤夷ǽޤä
εǽˤϡԡ
.BR sendfile (2)
Explicit Congestion Notification
TIME_WAIT åȤοˡ
keep-alive åȥץ
Duplicate SACK ĥΥݡȤʤɤ롣
.SS ɥ쥹Υեޥå
TCP  IP ξؤ˹ۤƤ
.RB ( ip (7)
򻲾)
.BR ip (7)
Ƥ륢ɥ쥹եޥåȤ TCP ˤŬѤ롣
TCP  point-to-point ̿򥵥ݡȤ롣
֥ɥ㥹Ȥޥ㥹ȤϥݡȤʤ
.SS sysctl
ѿ˥ˤϡ
.I proc/sys/net/ipv4/*
եɤ߽񤭤ˡȡ󥿡եФ
.BR sysctl (2)
Ѥˡ롣
äơۤȤɤ IP sysctl  TCP ˤŬѤǤ롣
.BR ip (7)
򻲾ȤΤȡ
.I Boolean
ͤǡ
0 ʳ ("true") б륪ץͭ
0  ("false") ̵Ǥ뤳Ȥ̣롣
.\" FIXME 2006/09 ߤ ͥ 2.6.18-rc5 Ǥϡ
.\"	ʲޤܤƤʤ (ǥեͤܤƤ):
.\"
.\"     /proc/sys/net/ipv4/tcp_congestion_control (since 2.6.13)
.\"     bic
.\"     /proc/sys/net/ipv4/tcp_moderate_rcvbuf
.\"     1
.\"     /proc/sys/net/ipv4/tcp_no_metrics_save
.\"     0
.TP
.IR tcp_abort_on_overflow " (Boolean; default: disabled)"
³ԤƤ륵ӥ٤ơˤĤƤʤˡ
³ꥻåȤǤ褦ˤ롣
ѤȡСȤˤäƥСեäȤˡ
³Ǥ褦ˤʤ롣ΥץѤΤϡ
ǡ®Ǥʤˡָꤹפȡ
ΥץѤȡΥФ³Ƥ륯饤
ˤȤäƤϳˤʤ뤳Ȥ롣
.TP
.IR tcp_adv_win_scale " (integer; default: 2)"
Хåե󥰤ΥСإåɤη׻ˡ
.I tcp_adv_win_scale
ξ bytes/2^tcp_adv_win_scale ˡ
.I tcp_adv_win_scale
餫 0 ξ bytes-bytes/2^(\-tcp_adv_win_scale) Ȥ롣

åȤμХåե֤ϥץꥱȥͥǶͭ롣
TCP ϥХåեΰ TCP ɥȤƴ
ɥȤ³¾üΤ롣
֤λĤϡ֥ץꥱץХåեȤѤ졢
塼󥰤䥢ץꥱٱ䤫ͥåȥΥ롣
.I tcp_adv_win_scale
Υǥեͤ 2 Ǥꡢ
ξ祢ץꥱХåեΤ 1/4 ˤʤ롣
.TP
.IR tcp_app_win  " (integer; default: 31)"
ѿϡTCP ɥβХʬ
Хåե󥰤ΥСإåѤͽ󤹤뤫ꤹ롣

Υɥ \fIwindow/2^tcp_app_win\fP  mss 礭ۤ (Хñ)
ץꥱХåեȤͽ󤵤롣
0 ꤹȰͽΰʤ
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_bic " (Boolean; default: disabled)"
BIC TCP 楢르ꥺͭˤ롣
BIC-TCP ¦Τߤѹǡ
ӥƥ TCP  (friendliness) ξ󶡤Ĥġ
礭ʥɥβǤ RTT ʿݾڤΤǤ롣
ΥץȥǤ additive increase (ɲŪ) 
binary search increase (ʬõ) ȤĤλȤߤ
Ȥ߹碌Ƥ롣ԥɥ礭Ȥϡʬ礭
additive increase ˤꡢӥƥݤʤ
 RTT ʿݾڤ롣
ԥɥȤˤ binary search increase ˤ
TCP ãƤ롣
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_bic_low_window " (integer; default: 14)"
BIC TCP ԥɥĴ򳫻Ϥͥɥ (ѥåñ)
ꤹ롣ͤ򲼲硢BIC TCP ϥǥեȤ TCP Reno 
Ʊư򤹤롣
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_bic_fast_convergence " (Boolean; default: enabled)"
BIC TCP ԥɥѲˤ®ȿ褦ˤ롣
ƱͥͭĤΥեĤˤޤȤޤΤ
®Ԥ褦ˤ롣
.TP
.IR tcp_dsack " (Boolean; default: enabled)"
RFC\ 2883  TCP Duplicate SACK ΥݡȤͭˤ롣
.TP
.IR tcp_ecn " (Boolean; default: disabled)"
RFC\ 2884  Explicit Congestion Notification ͭˤ롣
ͭˤȡְä񤤤򤹤Ť롼
ϩˤ褦³ФƱƶ
ˤäƤ³뤫⤷ʤ
.TP
.IR tcp_fack " (Boolean; default: enabled)"
TCP Forward Acknowledgement ΥݡȤͭˤ롣
.TP
.IR tcp_fin_timeout " (integer; default: 60)"
åȤŪ˥ˡ
Ǹ FIN ѥåȤԤĻ֤ñ̤ǻꤹ롣
ϸ̩ˤ TCP λͤƤʤ
DoS  (denial of service attack) Ȥ뤿ɬפǤ롣
Linux 2.2 Ǥϥǥեͤ 180 Ǥä
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_frto " (Boolean; default: disabled)"
TCP ॢȤǽ夵르ꥺǤ롢
F-RIO ͭˤ롣εǽ̵Ķä˸̤ȯ롣
̵ĶǤϡ̾ϡ֥롼ԤǤϤʤ̵δ
ˤѥåȥȯ롣
.TP
.IR tcp_keepalive_intvl " (integer; default: 75)"
TCP keep-alive Υץֳ֤ (ñ)
.TP
.IR tcp_keepalive_probes " (integer; default: 9)"
TCP keep-alive ץ֤κ
βƤ³褫ȿʤϡ
³Ǥ롣
.TP
.IR tcp_keepalive_time " (integer; default: 7200)"
³ɥ֤ˤʤäƤ顢keep-alive
ץ֤ޤǤλ֤ñ̤ǻꤹ롣
.B SO_KEEPALIVE
åȥץͭˤʤäƤʤ
keep-alive ʤ
ǥեͤ 7200  (2 )
keep-alive ͭˤʤäƤ硢
ˤ褽 11 ʬ (75 ôֳ֤ 9 ץʬ)
в᤹ȥɥ֤³Ͻλ롣

ؤˤ³׵䥢ץꥱǤΥॢȤϡ
äȤäû⤷ʤ
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_low_latency  " (Boolean; default: disabled)"
ͭˤȡTCP åϥ롼ץåȤ⤯
ٱ򾯤ʤ뤳Ȥͥ褷ȽǤԤ
Υץ̵ˤȡ롼ץåȤ⤯뤳Ȥͥ褵롣
Υǥեͤѹ褤ץꥱȤƤ
Beowulf ԥ塼饹󤲤
.TP
.IR tcp_max_orphans  " (integer; default: )"
ƥबƤ롢
orphan  (ɤΥ桼եϥɥˤ⥢åƤʤ)
TCP åȤκ
οۤȡorphan ³ϥꥻåȤ졢ٹɽ롣
¤¸ߤΤϡñʻǽ (denial-of-service) 
ɤ˲᤮ʤͤ򾮤뤳ȤϿ侩ʤ
ͥåȥξˤäƤϡοͤ礭ʤȤʤ⤷ʤ
orphan ʥåȤҤȤĤ
64K ٤ΥåԲǽʥ񤹤뤳Ȥդ衣
ǥեȤνͤϥͥѥ᡼ NR_FILE 
νǥեͤϥƥΥ˱Ĵ롣
.TP
.IR tcp_max_syn_backlog " (integer; default: )"
³ƤƤ륯饤Ȥ
ack Ƥʤ֤³ꥯȤ򥭥塼֤
οͤۤȡͥϥꥯȤΤƻϤ롣
ǥեȤͤ 256 ǡ
ƥ˽ʬʥ꤬ (128Mb ʾ)  1024 ˤʤꡢ
꤬˾ʤ (32 Mb ʲ)  128 ˤʤ롣
οͤ 1024 ʾ䤷ϡ
.I include/net/tcp.h
 TCP_SYNQ_HSIZE 
TCP_SYNQ_HSIZE*16<=tcp_max_syn_backlog Τ褦˽
ͥƥѥ뤹뤳Ȥ򾩤롣
.TP
.IR tcp_max_tw_buckets " (integer; default: )"
ƥबƤ TIME_WAIT ֤ˤ륽åȤκ
¤¸ߤΤϡ
ñʻǽ (denial-of-service) ɤ˲᤮ʤ
ǥեͤ NR_FILE*2 ǡƥΥ˱Ĵ롣
οͤۤȡΤ褦ʥåȤϥ졢ٹɽ롣
.TP
.I tcp_mem
 3 Ĥ [low, pressure, high] ʤ٥ȥͤǤ롣
 TCP ̤פ뤿Ѥ롣
ǥեȤϥ֡ȻѤǤ̤׻롣
(ºݤˤϡTCP 
.I "low memory"
ΤߤѤ롣ͤ 32ӥåȥƥǤ 900 ᥬХȤ¤롣
64 ӥåȥƥǤϤ¤Ϥʤ)

.I low
- TCP ϡХ˥ȤڡοͰʲξϡ
ꥢĴʤ

.I pressure
- TCP Ȥ꤬οʬΥڡۤȡ
TCP ϥޤ褦ˤʤ롣
Ȥڡ
.I low
ʲˤʤȡΥ갵֤æ롣

.I high
- TCP Х˳Ƥڡκ͡
ͤϥͥˤäƲݤ뤢¤ͥ褵롣
.TP
.IR tcp_orphan_retries " (integer; default: 8)"
餫饯³ˤĤơ
ץ֤Կ
.TP
.IR tcp_reordering " (integer; default: 3)"
TCP ѥåȥȥ꡼ǥѥåȽεžȯǤꡢ
ѥåȥäȤϤߤʤʤѥåȿκ͡
ͤĶƥѥåȤνžȡѥåȥ
ߤʤslow start 롣
οͤѹʤۤɤ
ϡ³ΥѥåȤ¤ؤˤä
ɬפ®㲼Ǿ褦߷פ줿
ѥå¤ؤ (packet reordering) θΥȥåʤΤǤ롣
.TP
.IR tcp_retrans_collapse " (Boolean; default: enabled)"
κݤ˥ե륵ΥѥåȤȤ롣
.TP
.IR tcp_retries1 " (integer; default: 3)"
̤˳ΩƤ³ˡ
TCP ͥåȥؤ򴬤ޤ˺ߤ
βۤȡޤǽˡ
˲ǽʤͥåȥؤ˷ϩ򹹿롣
ǥեȤ RFC ꤷƤǾǤ 3
.TP
.IR tcp_retries2 " (integer; default: 15)"
Ω֤³ˡβ TCP ѥåȤκ
ԤʤäƤʾϤ롣
ǥեͤ 15 ǡ (ΥॢȤ˰¸뤬)
褽 1330 ʬ٤δ֤б롣
RFC\ 1122 ϺǾθ³ 100 ä֤Ƥ뤬
ϤƤξˤûȻפ롣
.TP
.IR tcp_rfc1337 " (Boolean; default: disabled)"
TCP ư RFC\ 1337 ˽򤵤롣
̵ˤȡTIME_WAIT ֤ΤȤ RST 줿硢
TIME_WAIT ֤νλԤˤΥåȤľ˥롣
.TP
.I tcp_rmem
 3 Ĥ [min, default, max] ʤ٥ȥͤǤ롣
 TCP ХåեĴ뤿Ѥ롣
TCP ϡƥѤǤ˱ơ
ХåեΥ򤳤 sysctl ѿϰϤ
ʲ˼ǥեȤưŪĴ롣

.I min
-  TCP åȤѤХåեκǾ
ǥեͤ 4K ХȤǡξʤƥǤ
.B PAGE_SIZE
ХȤ˸餵롣
ͤϡ갵⡼ɤˤƤ⡢
ΥγƤ뤳Ȥݾڤ뤿Ѥ롣
ϡ
.B SO_RCVBUF
ѤƥåȤκХåեݤˤѤʤ
.\"nakano Documentation/networking/ip-sysctls.txt
.\"nakano ߤ¤ǤϤƤΤ褦ʡ

.I default
- TCP åȤμХåեΥǥեȥ
ͤϡ٤ƤΥץȥФƤ롢
ͥåʥХΥǥեȥХåե
.I net.core.rmem_default
ͥ褵롣
ǥեͤ 87380 ХȤǡξʤƥǤ
43689 ˤޤǸ餵롣
礭ʼХåեɬפʾϡ
ͤ䤹٤Ǥ (٤ƤΥåȤ˱ƶ)
礭 TCP ɥѤˤϡ
.I net.ipv4.tcp_window_scaling
ͭˤƤʤФʤʤ (ǥեȤͭ)

.I max
-  TCP åȤѤХåեκ祵
ͤ⥰Х
.I net.core.rmem_max
ͥ褵롣
ϡ
.B SO_RCVBUF
ѤƥåȤμХåե¤ݤˤѤʤ
.\"nakano Ʊ塣
ǥեͤ 87380*2 ХȤǡξʤƥǤ
87380 ˤޤǸ餵롣
.TP
.IR tcp_sack " (Boolean; default: enabled)"
RFC\ 2018  TCP Selective Acknowledgements ͭˤ롣
.TP
.IR tcp_stdurg " (Boolean; default: disabled)"
Υץͭˤȡ TCP ۵ޥݥ (urgent-pointer)
եɤ RFC\ 1122 ˽äԤ
.\" RFC\ 793 ϶۵ޥݥ󥿤ΰ̣ε꤬ۣǤä
.\" RFC\ 1122 ( RFC\ 961) ǤϤۣ椵˰Ĥβ᤿
.\" (ǰʤ "ְä" Ǥä)
β˽ȡ۵ޥݥ󥿤϶۵ޥǡκǸΥХȤؤ
Υץ̵ˤȡ۵ޥݥ󥿤β᤬ BSD ߴˡ
Ԥ: ۵ޥݥ󥿤϶۵ޥǡθκǽΥХȤؤ
Υץͭˤȡ꤬߱뤫⤷ʤ
.TP
.IR tcp_synack_retries " (integer; default: 5)"
passive  TCP ³ SYN/ACK ȤǺߤ
οͤ 255 礭٤ǤϤʤ
.TP
.IR tcp_syncookies " (Boolean)"
.TCP syncookies ͭˤ롣ͥ
.B CONFIG_SYNCOOKIES
Ĥƥѥ뤷ƤʤФʤʤ
åȤΥХå塼Сեȡ
syncookies 롣
syncookies ǽϡSYN flood ⤫饽åȤȤ롣
ϤˤƤ⡢ǽʤȤѤ٤Ǥ롣
 TCP ץȥ˰ȿƤꡢ
TCP ĥΤ褦ʡTCP ¾ʬȾͤƤޤ
饤Ȥ졼꤬뤳Ȥ⤢롣
٤ְ㤤ˤä٤礭ʾ֤ˤ륵ФĴƵߤ
Ȥߤʤ٤ǤϤʤ
Τ褦Ӥˤϡ
.IR tcp_max_syn_backlog ,
.IR tcp_synack_retries ,
.I tcp_abort_on_overflow
ʤɤλѤͤ뤳ȡ
.TP
.IR tcp_syn_retries  " (integer; default: 5)"
ƥ֤ TCP ³˽ SYN κߤ
οͤ 255 礭٤ǤϤʤ
ǥեȤͤ 5 ǡ褽 180 äб롣
.TP
.IR tcp_timestamps " (Boolean; default: enabled)"
RFC\ 1323  TCP timestamps ͭˤ롣
.TP
.IR tcp_tw_recycle " (Boolean; default: disabled)"
TIME_WAIT åȤᤤѤͭˤ롣
Υץͭˤȡ
NAT (ͥåȥɥ쥹Ѵ) ѤƤ꤬Τǡ
ޤ侩ʤ
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_tw_reuse " (Boolean; default: disabled)"
ץȥ̤鸫ʤ˿ͥ TIME_WAIT
֤ΥåȤѤ뤳ȤĤ롣Ū˾ܤͤν
ʤˤΥץѹ٤ǤϤʤ
.TP
.IR tcp_window_scaling " (Boolean; default: enabled)"
RFC\ 1323  TCP ɥ󥰤ͭˤ롣
εǽѤȡ³褬бƤС
TCP ³礭 (64K ʾ) ɥȤ褦ˤʤ롣
̾ TCP إåΥɥĹեɤ 16 ӥåȤʤΤǡ
ɥ 64K ХȰʲ˸¤롣
ä礭ʥɥȤϡ
ץꥱϥåȥХåեΥ䤷ơ
ɥ󥰤ΥץѤФ褤
.I tcp_window_scaling
̵ˤƤȡ
TCP ¾üȤ³κݤˡ
ɥ󥰤ΥͥԤʤʤ
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_vegas_cong_avoid  " (Boolean; default: disabled)"
TCP Vegas 楢르ꥺͭˤ롣
TCP Vegas Ӱ¬뤳ȤԤεϤͽۤ褦
TCP ¦ΤߤѹäΤǤ롣
TCP Vegas ԥɥ뤳Ȥǡ졼ȤĴ롣
TCP Vegas  TCP Reno ٤ƥѥåȥϾʤ
TCP Reno ۤѶŪʵưϤʤ
.\"
.\" The following is from 2.6.12: Documentation/networking/ip-sysctl.txt
.TP
.IR tcp_westwood " (Boolean; default: disabled)"
TCP Westwood+ 楢르ꥺͭˤ롣
TCP Westwood+  TCP ǽŬ褦 TCP Reno 
ץȥ륹å¦Τߤ˽äΤǤ롣
Ԥäǡԥɥ slow start ͤ
̿ξü֤Ӱο¬˴Ťꤹ롣
ο¬ȤäơTCP Westwood+ Ԥȯ˻ȤäƤ
Ӱθ줿 slow start ͤԥɥꤹ롣
TCP Westwood+ ϡͭͥåȥˤ TCP Reno θʿ
(fairness) ȡ̵󥯤ǤΥ롼ץåȤ礭夹롣
.TP
.I tcp_wmem
 3 Ĥ [min, default, max] ʤ٥ȥͤǤ롣
 TCP ХåեĴ뤿Ѥ롣
TCP ϡƥѤǤ˱ơ
ХåեΥ򤳤 sysctl ѿϰϤ
ʲ˼ǥեȤưŪĴ롣

.I min
-  TCP åȤѤХåեκǾ
ǥեͤ 4K Ǥ롣
ͤϡ갵⡼ɤˤƤ⡢
ΥʲγƤ뤳Ȥݾڤ뤿Ѥ롣
ϡ
.B SO_SNDBUF
ѤƥåȤκХåեݤˤѤʤ

.I default
- TCP åȤХåեΥǥեȥ
ͤϡ٤ƤΥץȥФƤ롢
ͥåʥХΥǥեȥХåե
.I net.core.rmem_default
ͥ褵롣
ǥեͤ 16K ХȤǤ롣
礭Хåեɬפʾϡ
ͤ䤹٤Ǥ (٤ƤΥåȤ˱ƶ)
礭 TCP ɥѤˤϡ
.I net.ipv4.tcp_window_scaling
ͭˤƤʤФʤʤ (ǥեȤͭ)

.I max
-  TCP åȤѤХåեκ祵
ͤ⥰Х
.I net.core.wmem_max
ͥ褵롣

.B SO_SNDBUF
ѤƥåȤХåե¤ݤˤѤʤ
ǥեͤ 128K ХȤǡƥΥꥵ˱
64K ˤޤǸ餵롣
.SS åȥץ
TCP åȤΥץϡ
ץ٥
.I IPPROTO_TCP
ꤷ
.BR setsockopt (2)
Ǥ
.BR getsockopt (2)
ǼǤ롣
ˡۤȤɤ
.B IPPROTO_IP
åȥץ TCP åȤФͭǤ롣ܺ٤
.BR ip (7)
򸫤衣
.\" FIXME Document TCP_CONGESTION (new in 2.6.13)
.TP
.B TCP_CORK
åȤȡ partial ե졼ʤ
Υץ󤬲ȡ
塼󥰤줿 partial ե졼ब롣
.BR sendfile (2)
Ƥ˥إå֤ꡢ
롼ץåȤŬǤ롣
ߤμǤϡ
.B TCP_CORK
ǽϤޤ뤳ȤǤ֤ξ¤ 200 ߥäǤ롣
ξ¤ãȡ塼󥰤줿ǡϼưŪ롣
Linux 2.5.71 ʹߤˤƤΤߡΥץ
.B TCP_NODELAY
ƱѤ뤳ȤǤ롣
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_DEFER_ACCEPT
ѤȡꥹʤϥǡåȤ夷ΤܳФ褦ˤʤ롣
 () Ȥꡢ
TCP ³λ褦Ȼߤ¤Ǥ롣
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_INFO
ΥåȤξΤѤ롣
ͥ
.I /usr/include/linux/tcp.h
եƤ
\fIstruct tcp_info\fP ֤
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_KEEPCNT
³Ȥ TCP ߤ keepalive ץ֤κ
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_KEEPIDLE
λ (ñ) ۤ³ɥ֤αޤäƤȡ
ΥåȤ
.B SO_KEEPALIVE
åȥץꤵƤ硢
TCP  keepalive ץ֤Ϥ롣
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_KEEPINTVL
 keepalive ץ֤δֳ (ñ)
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_LINGER2
orphan 줿 FIN_WAIT2 ֤ΥåȤμ̿
ΥץѤȡƥ磻ɤ sysctl
.I tcp_fin_timeout
ͤ򡢤ΥåȤФƤΤѹǤ롣
.BR socket (7)
٥Υץ
.B SO_LINGER
ȺƱʤȡ
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_MAXSEG
 TCP ѥåȤκ祻ȥ
Υץ³Ωꤹȡ
ѥåȤ¾ü˥ʥ󥹤 MSS ͤѲ롣
󥿡ե MTU 礭 (뤤礭ʤäƤޤä)
ͤϸ̤ʤ
ޤ TCP ϡͤǾ¤ͥ褹롣
.TP
.B TCP_NODELAY
ꤹ Nagle 르ꥺ̵ˤ롣
ʤǡ̤ʤǤ
ƥȤϲǽʸ¤᤯롣
ꤵƤʤȡ
ʬίޤޤǥǡϥХåե졢
ʥѥåȤˤ餺ˤߡ
ͥåȥͭѤǤ롣
Υץ
.B TCP_CORK
ˤ񤭤롣ʤ顢
.B TCP_CORK
ꤵƤǤäƤ⡢Υץꤹȡ
ԤνϤŪݤФ (flush) Ȥˤʤ롣
.TP
.B TCP_QUICKACK
ꤵƤ quickack ⡼ɤͭˤꥢ̵ˤ롣
̾ TCP ưǤ ack ɬפ˱ٱ䤵ΤФ
quickack ⡼ɤǤ ack Ϥ롣
Υե饰ϱ³ŪʤΤǤϤʤ
quickack ⡼ɤ/⡼ɤڤؤ뤿ΤΤǤ롣
ʹߤ TCP ץȥưˤäƤϡ
Υץȥ䡢ٱ ack ॢȤȯ
ǡžʤɤװˤäơ
Ƥ quickack Фäꤹ롣
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_SYNCNT
³λԤߤ TCP  SYN ꤹ롣
 255 礭ϤǤʤ
ܿɬפʥץǤϤΥץѤ٤ǤϤʤ
.TP
.B TCP_WINDOW_CLAMP
󤹤륦ɥΥ򤳤ͤ˸ꤹ롣
ͥˤäƺǾ SOCK_MIN_RCVBUF/2 ¤Ƥ롣
ΥץϰܿɬפʥɤǤѤ٤Ǥʤ
.SS ioctl
ʲ
.BR ioctl (2)
ƤӽФ
.I value
˾֤
񼰤ϰʲ̤ꡣ
.PP
.RS
.nf
.BI int " value";
.IB error " = ioctl(" tcp_socket ", " ioctl_type ", &" value ");"
.fi
.RE
.PP
.I ioctl_type
ϰʲΤ줫ĤǤ:
.TP
.B SIOCINQ
ХåեΥ塼ˤ롢ޤɤǤʤǡ̤֤
åȤ LISTEN ֤ˤäƤϤʤ餺
ʤȥ顼
.RB ( EINVAL )
֤롣
.TP
.B SIOCATMARK
ǡȥ꡼ब۵ޥޡΰ֤ǤС֤ (Ĥޤ
.I value
 0 ʳ)
.sp
.B SO_OOBINLINE
åȥץꤵƤơ
.B SIOCATMARK
֤硢ΥåȤɤ߹ߤǤ϶۵ޥǡ
֤롣
.B SO_OOBINLINE
åȥץꤵƤ餺
.B SIOCATMARK
֤硢ΥåȤɤ߹ߤǤ϶۵ޥǡ
³ǡ֤ (ºݤ˶۵ޥǡɤ߹ˤ
.B recv(MSG_OOB)
ȥե饰Ĥɬפ)

ǡΰɤ߹ߤǤ϶۵ޥޡ٤äƤɤ߹ߤϹԤʤ
ץꥱ󤬶۵ޥǡ¸ߤ
.RI ( exceptfds
Ȥä)
.BR select (2)
ͳޤ
.B SIGURG
ʥ̤Τ餵줿硢
.B SIOCATMARK
Υåɤ߹ (Хɤ߹׵򤷤Ƥ褤) 
.B SIOCATMARK
֤ʤʤޤǷ֤ԤȤǡ۵ޥޡΰ֤ޤ
ɤ߿ʤ뤳ȤǤ롣
.TP
.B SIOCOUTQ
åȤ塼˻ĤäƤ̤ǡ̤֤
åȤ LISTEN ֤ˤäƤϤʤʤ
LISTEN ֤ξˤϥ顼
.RB ( EINVAL )
Ȥʤ롣
.SS 顼
ͥåȥ顼ȡ TCP ϥѥåȤκߤ롣
󤫤äƤʤС³Ф
.B ETIMEOUT
顼Ǹ˼顼֤롣
.PP
ץꥱˤäƤϡä᤯顼Τ餻Ƥۤ礬롣
ˤ
.B IPPROTO_IP
٥
.B IP_RECVERR
åȥץѤɤΥץͭˤʤäƤȡ
夷顼Ϥ٤Ƥ˥桼ץϤ롣
ΥץϿŤѤ뤳 \(em 롼ƥ󥰤ѹʤɡ
̾濫ꤦͥåȥ֤Ф TCP ȼˤƤޤ
.SH 顼
.TP
.B EAFNOTSUPPORT
.I sin_family
Ϥ줿åȥɥ쥹Υפ
.B AF_INET
ǤϤʤä
.TP
.B EPIPE
³褬ͽʤäǥåȤ򥯥
ޤϥåȥ󤵤줿åȤɤ߹ߤ¹Ԥ줿
.TP
.B ETIMEDOUT
³褬󤫥ǡƤȿʤ
.PP
.BR ip (7)
Ƥ륨顼䡢ͥåʥåؤˤ륨顼
TCP ֤뤳Ȥ롣
.SH С
Explicit Congestion Notificationzero-copy 
.BR sendfile (2)
¤ؤΥݡȡSACK ĥ (DSACK) ʤɤΥݡȤ
2.4 Ƴ줿
եɳǧ (FACK)TIME_WAIT ꥵ롢
³Ȥ keepalive ʤɤФ륽åȥץ sysctl 
2.3 Ƴ줿

ʸͿ sysctl ѿΥǥեͤȲϡ
2.4 ͥΤΤǤ롣
.SH 
TCP ˤΰ̣ǤӰ賰ǡ (out-of-band data) Ϥʤ
TCP ĤΤ϶۵ޥǡǤ롣Ĥޤ Linux ˤƤϡ
³褬 () Ӱ賰ǡäƤ硢
(Ť)
۵ޥǡ̾ΥǡȤƥȥ꡼뤳Ȥˤʤ (
.B SO_OOBINLINE
åȤƤǤƱͤǤ)
 BSD ١ΥåȤϰۤʤ롣
.PP
Linux ϡǥեȤǤ urgent ݥ󥿥եɤβ
BSD ߴˡѤ롣 RFC\ 1122 ȿƤ뤬
¾ΥåƱưˤϤʤ
.I tcp_stdurg
sysctl ˤäѹǤ롣
.SH Х
ޤƤʤ顼롣
.br
IPv6 ˴ؤ뵭Ҥʤ
.\" Only a single Linux kernel version is described
.\" Info for 2.2 was lost. Should be added again,
.\" or put into a separate page.
.\" .SH 
.\"  man ڡϺǽ Andi Kleen ˤäƽ񤫤줿
.\" Alexey Kuznetsov ʸ Documentation/networking/ip-sysctl.txt
.\" ξ򸵤ˡNivedita Singhvi  2.4 ˹
.SH Ϣ
.BR accept (2),
.BR bind (2),
.BR connect (2),
.BR getsockopt (2),
.BR listen (2),
.BR recvmsg (2),
.BR sendfile (2),
.BR sendmsg (2),
.BR socket (2),
.BR sysctl (2),
.BR ip (7),
.BR socket (7)
.sp
RFC\ 793: TCP λ͡
.br
RFC\ 1122: TCP ׵ Nagle 르ꥺεҡ
.br
RFC\ 1323: TCP Υॹסɥ󥰳ƥץ
.br
RFC\ 1644: TIME_WAIT assassination hazard ˴ؤ뵭ҡ
.br
RFC\ 3168: Explicit Congestion Notification ˴ؤ뵭ҡ
.br
RFC\ 2581: TCP 楢르ꥺࡣ
.br
RFC\ 2018  RFC\ 2883: SACK Ȥγĥ