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Version: 2005-06-15 (openSuse - 09/10/07)

Section: 7 (Divers)

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tcp - TCP ¥×¥í¥È¥³¥ë

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#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
tcp_socket = socket(PF_INET, SOCK_STREAM, 0);

ÀâÌÀ

¤³¤ì¤Ï RFC 793, RFC 1122, RFC 2001 ¤ÇÄêµÁ¤µ¤ì¤Æ¤¤¤ë TCP ¥×¥í¥È¥³¥ë¤ò NewReno ³ÈÄ¥¤È SACK ³ÈÄ¥¤ò´Þ¤á¤Æ¼ÂÁõ¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£ TCP ¤Ï¡¢ ip(7) ¾å¤ÎÆó¤Ä¤Î¥½¥±¥Ã¥È´Ö¤Ë¡¢¿®ÍêÀ¤Î¹â¤¤¡¢¥¹¥È¥ê¡¼¥à»Ø¸þ¤ÎÁ´Æó½Å (full-duplex) ÄÌ¿®¤òÄó¶¡¤¹¤ë¡£ v4 ¤È v6 ¤ÎÎ¾Êý¤Î¥Ð¡¼¥¸¥ç¥ó¤Î ip(7) ¤ËÂÐ±þ¤·¤Æ¤¤¤ë¡£ TCP ¤Ï¡¢¥Ç¡¼¥¿¤¬½ç½ø¤ò¼é¤Ã¤ÆÅþÃå¤¹¤ë¤³¤È¡¢ÅÓÃæ¤Ç¼º¤ï¤ì¤¿¥Ñ¥±¥Ã¥È¤¬ ºÆÁ÷¤µ¤ì¤ë¤³¤È¤òÊÝ¾Ú¤¹¤ë¡£¤Þ¤¿¡¢¥Ñ¥±¥Ã¥ÈÃ±°Ì¤Ë¥Á¥§¥Ã¥¯¥µ¥à¤ò À¸À®¡¢¸¡ºº¤¹¤ë¤³¤È¤Ç¡¢Å¾Á÷¥¨¥é¡¼¤ò¸¡ÃÎ¤¹¤ë¡£ TCP ¤Ï¥ì¥³¡¼¥É¶³¦ (record boundary) ¤òÊÝÂ¸¤·¤Ê¤¤¡£

¿·¤·¤¯À¸À®¤µ¤ì¤¿¤Ð¤«¤ê¤Î TCP ¥½¥±¥Ã¥È¤Ï¡¢ ¥ê¥â¡¼¥È¥¢¥É¥ì¥¹¤«¥í¡¼¥«¥ë¥¢¥É¥ì¥¹¤¬¤Ê¤¯¡¢ ¤·¤¿¤¬¤Ã¤Æ¾ÜºÙ¤¬´°Á´¤Ë»ØÄê¤µ¤ì¤¿¾õÂÖ¤Ç¤Ï¤Ê¤¤¡£ ³°Éô¤Ø¤Î TCP ÀÜÂ³¤òÀ¸À®¤¹¤ë¤Ë¤Ï¡¢ connect(2) ¤òÍÑ¤¤¤Æ¤â¤¦°ìÊý¤Î TCP ¥½¥±¥Ã¥È¤Ø¤ÎÀÜÂ³¤ò³ÎÎ©¤¹¤ë¡£ ³°Éô¤«¤é¤Î¿·¤¿¤ÊÀÜÂ³¤ò¼õ¤±¤ë¤Ë¤Ï¡¢¤Þ¤º bind(2) ¤Ç¥½¥±¥Ã¥È¤ò¥í¡¼¥«¥ë¤Ê¥¢¥É¥ì¥¹¤È¥Ý¡¼¥È¤Ë·ë¤Ó¤Ä¤±¡¢¼¡¤Ë listen(2) ¤ò¸Æ¤ó¤Ç¥½¥±¥Ã¥È¤òÀÜÂ³ÂÔ¤Á¼õ¤±¾õÂÖ¤Ë¤¹¤ë¡£ ¤½¤Î¸å¡¢ÅþÃå¤·¤¿ÀÜÂ³Í×µá¤ËÂÐ¤·¤Æ accept(2) ¤òÍÑ¤¤¡¢¥½¥±¥Ã¥È¤ò¿·¤·¤¯À¸À®¤¹¤ë¡£ accept(2) ¤Þ¤¿¤Ï connect(2) ¤Î¥³¡¼¥ë¤¬À®¸ù¤·¤¿¥½¥±¥Ã¥È¤Ï¡¢¾ÜºÙ¤¬´°Á´¤Ë»ØÄê¤µ¤ì¤¿¾õÂÖ¤È¤Ê¤ê¡¢ ¥Ç¡¼¥¿¤Î¤ä¤ê¤È¤ê¤¬²ÄÇ½¤È¤Ê¤ë¡£ÀÜÂ³ÂÔ¤Á¼õ¤±¾õÂÖ¤Î (listening) ¥½¥±¥Ã¥È¤ä¡¢ ÀÜÂ³ (connect) ¤µ¤ì¤Æ¤¤¤Ê¤¤¥½¥±¥Ã¥È¤òÄÌ¤·¤Æ¥Ç¡¼¥¿¤ò¤ä¤ê¤È¤ê¤¹¤ë¤³¤È¤Ï¤Ç¤¤Ê¤¤¡£

Linux ¤Ï RFC 1323 ¤Î TCP high performance ³ÈÄ¥¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤ë¡£ ¤³¤ì¤Ë¤Ï¡¢Protection Against Wrapped Sequence Numbers (PAWS)¡¢ ¥¦¥£¥ó¥É¥¦¥¹¥±¡¼¥ê¥ó¥°¡¢¥¿¥¤¥à¥¹¥¿¥ó¥×¤Ê¤É¤¬´Þ¤Þ¤ì¤Æ¤¤¤ë¡£ ¥¦¥£¥ó¥É¥¦¥¹¥±¡¼¥ê¥ó¥°¤òÍøÍÑ¤¹¤ë¤È¡¢ÃÙ±ä¤Þ¤¿¤ÏÂÓ°è¤ÎÂç¤¤ÊÀÜÂ³¤Ç¡¢ (64K °Ê¾å¤Î) µðÂç¤Ê TCP ¥¦¥£¥ó¥É¥¦¤òÍÑ¤¤¤ë¤³¤È¤¬²ÄÇ½¤È¤Ê¤ë¡£ ¤³¤ì¤òÍÑ¤¤¤ë¤Ë¤Ï¡¢Á÷¼õ¿®¤Î¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º¤òÂç¤¤¯¤·¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£ ¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º¤Ï sysctl ÊÑ¿ô net.ipv4.tcp_wmem ¤È net.ipv4.tcp_rmem ¤òÍÑ¤¤¤Æ¡¢¥·¥¹¥Æ¥àÁ´ÂÎ¤ÇÂç¤¤¯¤Ç¤¤ë¡£ ¤¢¤ë¤¤¤Ï¡¢¸Ä¡¹¤Î¥½¥±¥Ã¥È¤Î¤ß¤òÂç¤¤¯¤·¤¿¤¤¾ì¹ç¤Ë¤Ï¡¢ SO_SNDBUF ¤ä SO_RCVBUF ¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤òÍÑ¤¤¤Æ setsockopt(2) ¥³¡¼¥ë¤òÍÑ¤¤¤ÆÀßÄê¤¹¤ì¤Ð¤è¤¤¡£

SO_SNDBUF ¤ä SO_RCVBUF ¤Î¥á¥«¥Ë¥º¥à¤ÇÀë¸À¤µ¤ì¤ë¥½¥±¥Ã¥È¥Ð¥Ã¥Õ¥¡¤ÎºÇÂç¥µ¥¤¥º¤Ï¡¢ net.core.rmem_max ¤ä net.core.wmem_max sysctl ¤Ç»ØÄê¤µ¤ì¤¿¥·¥¹¥Æ¥à¤È¤·¤Æ¤ÎÀ©¸ÂÃÍ¤òÄ¶¤¨¤ë¤³¤È¤Ï¤Ç¤¤Ê¤¤¡£ TCP ¤Ï¼ÂºÝ¤Ë¤Ï setsockopt(2) ¥³¡¼¥ë¤¬Í×µá¤·¤¿¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º¤ÎÆóÇÜ¤ò³ä¤êÅö¤Æ¤ë¡£ ¤½¤Î¤¿¤á¡¢¤³¤Î¸å¤Ç getsockopt(2) ¥³¡¼¥ë¤ò¹Ô¤¦¤È¡¢ setsockopt(2) ¤ÇÍ×µá¤·¤¿¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º¤È¤Ï°Û¤Ê¤ëÃÍ¤¬ÊÖ¤ë¡£ TCP ¤Ï¤³¤ÎÍ¾Ê¬¤Ê¶õ´Ö¤ò¡¢´ÉÍýÌÜÅª¤ä¥«¡¼¥Í¥ëÆâÉô¤Î¹½Â¤ÂÎ¤ËÍÑ¤¤¤Æ¤ª¤ê¡¢ sysctl ÊÑ¿ô¤Ï¼ÂºÝ¤Î TCP ¥¦¥£¥ó¥É¥¦¤è¤ê¤âÂç¤¤Ê¥µ¥¤¥º¤òÈ¿±Ç¤¹¤ë¡£ ³ÆÀÜÂ³¤Ë¤ª¤±¤ë¥½¥±¥Ã¥È¤Î¥Ð¥Ã¥Õ¥¡¥µ¥¤¥ºÊÑ¹¹¤òÍ¸ú¤Ë¤¹¤ë¤Ë¤Ï¡¢ listen(2) ¤ä connect(2) ¥³¡¼¥ë¤ÎÁ°¤ËÀßÄê¤·¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£ ¤è¤ê¾Ü¤·¤¤¾ðÊó¤Ï socket(7) ¤ò¸«¤è¡£

TCP ¤Ï¶ÛµÞ¥Ç¡¼¥¿ (urgent data) ¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤ë¡£¶ÛµÞ¥Ç¡¼¥¿¤Ï ²¿¤é¤«¤Î½ÅÍ×¤Ê¥á¥Ã¥»¡¼¥¸¤¬¥Ç¡¼¥¿¥¹¥È¥ê¡¼¥à¤Ë´Þ¤Þ¤ì¤Æ¤¤¤ë¤³¤È¡¢ ¤½¤Î¥Ç¡¼¥¿¤ò¤Ç¤¤ë¤À¤±Áá¤¯½èÍý¤¹¤Ù¤¤³¤È¡¢¤ò¼õ¿®¼Ô¤ËÅÁ¤¨¤ë¤¿¤á¤ËÍÑ¤¤¤é¤ì¤ë¡£ ¶ÛµÞ¥Ç¡¼¥¿¤òÁ÷¤ë¤Ë¤Ï¡¢ send(2) ¤Ë MSG_OOB ¥ª¥×¥·¥ç¥ó¤ò»ØÄê¤¹¤ë¡£ ¶ÛµÞ¥Ç¡¼¥¿¤ò¼õ¿®¤¹¤ë¤È¡¢¥«¡¼¥Í¥ë¤Ï SIGURG ¥·¥°¥Ê¥ë¤òÁ÷¿®¤¹¤ë¡£Á÷¿®Àè¤Ï SIOCSPGRP ¤ä FIOSETOWN ioctl (¤ä POSIX.1-2001 ¤Çµ¬Äê¤µ¤ì¤Æ¤¤¤ë fcntl(2) F_SETOWN Áàºî) ¤òÍÑ¤¤¤Æ¤½¤Î¥½¥±¥Ã¥È¤Î¡Ö½êÍ¼Ô¡×¤È¤·¤ÆÀßÄê¤µ¤ì¤¿ ¥×¥í¥»¥¹¤«¥×¥í¥»¥¹¥°¥ë¡¼¥×¤Ç¤¢¤ë¡£ SO_OOBINLINE ¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤¬Í¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤ë¤È¡¢¶ÛµÞ¥Ç¡¼¥¿¤Ï ÄÌ¾ï¤Î¥Ç¡¼¥¿¥¹¥È¥ê¡¼¥à¤ÎÃæ¤Ëº®¤¼¤ÆÁ÷¤é¤ì¤ë (¥×¥í¥°¥é¥à¤Ï²¼µ¤Î SIOCATMARK ioctl ¤ò»È¤Ã¤Æ¶ÛµÞ¥Ç¡¼¥¿¤Î¾ì½ê¤òÄ´¤Ù¤ë¤³¤È¤¬¤Ç¤¤ë)¡£ Ìµ¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤ë¾ì¹ç¤Ë¤Ï¡¢ recv(2) ¤ä recvmsg(2) ¤Ç MSG_OOB ¥Õ¥é¥°¤¬¥»¥Ã¥È¤µ¤ì¤Æ¤¤¤ë¤È¤¤Ë¤Î¤ß¡¢¶ÛµÞ¥Ç¡¼¥¿¤ò¼õ¿®¤Ç¤¤ë¡£

Linux 2.4 ¤Ç¤ÏÂ¿¤¯¤ÎÊÑ¹¹¤¬¤Ê¤µ¤ì¡¢ ¥¹¥ë¡¼¥×¥Ã¥È¤È¥¹¥±¡¼¥ê¥ó¥°¤¬¸þ¾å¤·¡¢µ¡Ç½¤â¹â¤Þ¤Ã¤¿¡£ ¤³¤ì¤é¤Îµ¡Ç½¤Ë¤Ï¡¢¥¼¥í¥³¥Ô¡¼ sendfile(2)¡¢ Explicit Congestion Notification¡¢ TIME_WAIT ¥½¥±¥Ã¥È¤Î¿·¤·¤¤´ÉÍýË¡¡¢ keep-alive ¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¡¢ Duplicate SACK ³ÈÄ¥¤Î¥µ¥Ý¡¼¥È¤Ê¤É¤¬¤¢¤ë¡£

¥¢¥É¥ì¥¹¤Î¥Õ¥©¡¼¥Þ¥Ã¥È

TCP ¤Ï IP ¤Î¾åÁØ¤Ë¹½ÃÛ¤µ¤ì¤Æ¤¤¤ë (ip(7) ¤ò»²¾È)¡£ ip(7) ¤ËÄêµÁ¤µ¤ì¤Æ¤¤¤ë¥¢¥É¥ì¥¹¥Õ¥©¡¼¥Þ¥Ã¥È¤Ï TCP ¤Ë¤âÅ¬ÍÑ¤µ¤ì¤ë¡£ TCP ¤Ï point-to-point ¤ÎÄÌ¿®¤À¤±¤ò¥µ¥Ý¡¼¥È¤¹¤ë¡£ ¥Ö¥í¡¼¥É¥¥ã¥¹¥È¤ä¥Þ¥ë¥Á¥¥ã¥¹¥È¤Ï¥µ¥Ý¡¼¥È¤·¤Ê¤¤¡£

sysctl

¤³¤ì¤é¤ÎÊÑ¿ô¤Ë¥¢¥¯¥»¥¹¤¹¤ë¤Ë¤Ï¡¢ proc/sys/net/ipv4/* ¥Õ¥¡¥¤¥ë¤òÆÉ¤ß½ñ¤¤¹¤ëÊýË¡¤È¡¢¥¤¥ó¥¿¡¼¥Õ¥§¡¼¥¹¤ËÂÐ¤·¤Æ sysctl(2) ¤òÍÑ¤¤¤ëÊýË¡¤¬¤¢¤ë¡£ ²Ã¤¨¤Æ¡¢¤Û¤È¤ó¤É¤Î IP sysctl ¤Ï TCP ¤Ë¤âÅ¬ÍÑ¤Ç¤¤ë¡£ ip(7) ¤ò»²¾È¤Î¤³¤È¡£ Boolean ¤ÏÀ°¿ôÃÍ¤Ç¡¢ 0 °Ê³°¤ÎÃÍ ("true") ¤ÏÂÐ±þ¤¹¤ë¥ª¥×¥·¥ç¥ó¤¬Í¸ú¡¢ 0 ÃÍ ("false") ¤ÏÌµ¸ú¡¢¤Ç¤¢¤ë¤³¤È¤ò°ÕÌ£¤¹¤ë¡£

tcp_abort_on_overflow (Boolean; default: disabled)

tcp_adv_win_scale (integer; default: 2)

¥Ð¥Ã¥Õ¥¡¥ê¥ó¥°¤Î¥ª¡¼¥Ð¡¼¥Ø¥Ã¥É¤Î·×»»ÊýË¡¤ò¡¢ tcp_adv_win_scale ¤¬Àµ¤Î¾ì¹ç¤Ï bytes/2^tcp_adv_win_scale ¤Ë¡¢ tcp_adv_win_scale ¤¬Éé¤« 0 ¤Î¾ì¹ç¤Ï bytes-bytes/2^(-tcp_adv_win_scale) ¤È¤¹¤ë¡£

¥½¥±¥Ã¥È¤Î¼õ¿®¥Ð¥Ã¥Õ¥¡¶õ´Ö¤Ï¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤È¥«¡¼¥Í¥ë¤Ç¶¦Í¤µ¤ì¤ë¡£ TCP ¤Ï¥Ð¥Ã¥Õ¥¡¤Î°ìÉô¤ò TCP ¥¦¥£¥ó¥É¥¦¤È¤·¤Æ´ÉÍý¤·¡¢ ¤³¤ì¤ò¼õ¿®¥¦¥£¥ó¥É¥¦¤È¤·¤ÆÀÜÂ³¤ÎÂ¾Ã¼¤ËÄÌÃÎ¤¹¤ë¡£ ¶õ´Ö¤Î»Ä¤ê¤Ï¡Ö¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¡×¥Ð¥Ã¥Õ¥¡¤È¤·¤ÆÍÑ¤¤¤é¤ì¡¢ ¥¹¥±¥¸¥å¡¼¥ê¥ó¥°¤ä¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤ÎÃÙ±ä¤«¤é¥Í¥Ã¥È¥ï¡¼¥¯¤ò³ÖÎ¥¤¹¤ë¡£ tcp_adv_win_scale ¤Î¥Ç¥Õ¥©¥ë¥ÈÃÍ¤Ï 2 ¤Ç¤¢¤ê¡¢ ¤³¤Î¾ì¹ç¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¥Ð¥Ã¥Õ¥¡¤ÏÁ´ÂÎ¤Î 1/4 ¤Ë¤Ê¤ë¡£

tcp_app_win (integer; default: 31)

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¤½¤Î¥¦¥£¥ó¥É¥¦¤Î window/2^tcp_app_win ¤È mss ¤ÎÂç¤¤¤¤Û¤¦ (¥Ð¥¤¥ÈÃ±°Ì) ¤¬¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¥Ð¥Ã¥Õ¥¡¤È¤·¤ÆÍ½Ìó¤µ¤ì¤ë¡£ 0 ¤ò»ØÄê¤¹¤ë¤È°ìÀÚÍ½ÌóÎÎ°è¤ò¼è¤é¤Ê¤¤¡£

tcp_bic (Boolean; default: disabled)

BIC TCP íÕíÔÀ©¸æ¥¢¥ë¥´¥ê¥º¥à¤òÍ¸ú¤Ë¤¹¤ë¡£ BIC-TCP ¤ÏÁ÷¿®Â¦¤Î¤ß¤ÎÊÑ¹¹¤Ç¡¢ ¥¹¥±¡¼¥é¥Ó¥ê¥Æ¥£¤È TCP ¿ÆÏÂÀ (friendliness) ¤ÎÎ¾Êý¤òÄó¶¡¤·¤Ä¤Ä¡¢ Âç¤¤Ê¥¦¥£¥ó¥É¥¦¤Î²¼¤Ç¤ÎÀþ·Á¤Ê RTT ¸øÊ¿À¤òÊÝ¾Ú¤¹¤ë¤â¤Î¤Ç¤¢¤ë¡£ ¤³¤Î¥×¥í¥È¥³¥ë¤Ç¤Ï additive increase (ÄÉ²ÃÅª¤ÊÁý²Ã) ¤È binary search increase (ÆóÊ¬Ãµº÷Áý²Ã) ¤È¤¤¤ï¤ì¤ëÆó¤Ä¤Î»ÅÁÈ¤ß¤ò ÁÈ¤ß¹ç¤ï¤»¤Æ¤¤¤ë¡£íÕíÔ¥¦¥£¥ó¥É¥¦¤¬Âç¤¤¤¤È¤¤Ï¡¢ÁýÊ¬¤ÎÂç¤¤¤ additive increase ¤Ë¤è¤ê¡¢¥¹¥±¡¼¥é¥Ó¥ê¥Æ¥£¤ò³ÎÊÝ¤·¤Ê¤¬¤é Àþ·Á¤Ê RTT ¸øÊ¿À¤òÊÝ¾Ú¤¹¤ë¡£ íÕíÔ¥¦¥£¥ó¥É¥¦¤¬¾®¤µ¤¤¤È¤¤Ë¤Ï binary search increase ¤Ë¤è¤ê TCP ¿ÆÏÂÀ¤òÃ£À®¤·¤Æ¤¤¤ë¡£

tcp_bic_low_window (integer; default: 14)

BIC TCP ¤¬íÕíÔ¥¦¥£¥ó¥É¥¦¤ÎÄ´À°¤ò³«»Ï¤¹¤ëïçÃÍ¥¦¥£¥ó¥É¥¦ (¥Ñ¥±¥Ã¥ÈÃ±°Ì) ¤òÀßÄê¤¹¤ë¡£¤³¤ÎïçÃÍ¤ò²¼²ó¤ë¾ì¹ç¡¢BIC TCP ¤Ï¥Ç¥Õ¥©¥ë¥È¤Î TCP Reno ¤È Æ±¤¸Æ°ºî¤ò¤¹¤ë¡£

tcp_bic_fast_convergence (Boolean; default: enabled)

tcp_dsack (Boolean; default: enabled)

RFC 2883 ¤Î TCP Duplicate SACK ¤Î¥µ¥Ý¡¼¥È¤òÍ¸ú¤Ë¤¹¤ë¡£

tcp_ecn (Boolean; default: disabled)

RFC 2884 ¤Î Explicit Congestion Notification ¤òÍ¸ú¤Ë¤¹¤ë¡£ ¤³¤ì¤òÍ¸ú¤Ë¤¹¤ë¤È¡¢´Ö°ã¤Ã¤¿¿¶Éñ¤¤¤ò¤¹¤ë¸Å¤¤¥ë¡¼¥¿¤¬ ·ÐÏ©¤ÎÅÓÃæ¤Ë¤¢¤ë¤è¤¦¤ÊÀÜÂ³Àè¤ËÂÐ¤·¤Æ±Æ¶Á¤¬À¸¤¸¡¢ ¾ì¹ç¤Ë¤è¤Ã¤Æ¤ÏÀÜÂ³¤¬Íî¤Á¤ë¤«¤â¤·¤ì¤Ê¤¤¡£

tcp_fack (Boolean; default: enabled)

TCP Forward Acknowledgement ¤Î¥µ¥Ý¡¼¥È¤òÍ¸ú¤Ë¤¹¤ë¡£

tcp_fin_timeout (integer; default: 60)

¥½¥±¥Ã¥È¤ò¶¯À©Åª¤Ë¥¯¥í¡¼¥º¤¹¤ëÁ°¤Ë¡¢ ºÇ¸å¤Î FIN ¥Ñ¥±¥Ã¥È¤òÂÔ¤Ä»þ´Ö¤òÉÃÃ±°Ì¤Ç»ØÄê¤¹¤ë¡£ ¤³¤ì¤Ï¸·Ì©¤Ë¤Ï TCP ¤Î»ÅÍÍ¤òËþ¤¿¤·¤Æ¤¤¤Ê¤¤¤¬¡¢ DoS ¹¶·â (denial of service attack) ¤«¤é¿È¤ò¼é¤ë¤¿¤á¤ËÉ¬Í×¤Ç¤¢¤ë¡£ Linux 2.2 ¤Ç¤Ï¥Ç¥Õ¥©¥ë¥ÈÃÍ¤Ï 180 ¤Ç¤¢¤Ã¤¿¡£

tcp_frto (Boolean; default: disabled)

TCP ºÆÁ÷¥¿¥¤¥à¥¢¥¦¥È¤«¤é¤ÎÉüµìÀÇ½¤ò¸þ¾å¤µ¤»¤¿¥¢¥ë¥´¥ê¥º¥à¤Ç¤¢¤ë¡¢ F-RIO ¤òÍ¸ú¤Ë¤¹¤ë¡£¤³¤Îµ¡Ç½¤ÏÌµÀþ´Ä¶¤ÇÆÃ¤Ë¸ú²Ì¤òÈ¯´ø¤¹¤ë¡£ ÌµÀþ´Ä¶¤Ç¤Ï¡¢ÄÌ¾ï¤Ï¡¢Ãæ´Ö¥ë¡¼¥¿¤ÎíÕíÔ¤Ç¤Ï¤Ê¤¯¥é¥ó¥À¥à¤ÊÌµÀþ¤Î´³¾Ä ¤Ë¤è¤ê¥Ñ¥±¥Ã¥È¥í¥¹¤¬È¯À¸¤¹¤ë¡£

tcp_keepalive_intvl (integer; default: 75)

TCP keep-alive ¤Î¥×¥í¡¼¥Ö¤òÁ÷¤ë´Ö³Ö (ÉÃÃ±°Ì)¡£

tcp_keepalive_probes (integer; default: 9)

TCP keep-alive ¥×¥í¡¼¥Ö¤ÎºÇÂç²ó¿ô¡£ ¤³¤Î²ó¿ô¤À¤±»î¤·¤Æ¤âÀÜÂ³Àè¤«¤éÈ¿±þ¤¬ÆÀ¤é¤ì¤Ê¤¤¾ì¹ç¤Ï¡¢ ¤¢¤¤é¤á¤ÆÀÜÂ³¤òÀÚÃÇ¤¹¤ë¡£

tcp_keepalive_time (integer; default: 7200)

ÀÜÂ³¤¬¥¢¥¤¥É¥ë¾õÂÖ¤Ë¤Ê¤Ã¤Æ¤«¤é¡¢keep-alive ¥×¥í¡¼¥Ö¤òÁ÷¿®¤¹¤ë¤Þ¤Ç¤Î»þ´Ö¤òÉÃÃ±°Ì¤Ç»ØÄê¤¹¤ë¡£ SO_KEEPALIVE ¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤¬Í¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤Ê¤¤¤È keep-alive ¤ÏÁ÷¤é¤ì¤Ê¤¤¡£ ¥Ç¥Õ¥©¥ë¥ÈÃÍ¤Ï 7200 ÉÃ (2 »þ´Ö)¡£ keep-alive ¤¬Í¸ú¤Ë¤Ê¤Ã¤Æ¤¤¤ë¾ì¹ç¡¢ ¤µ¤é¤Ë¤ª¤è¤½ 11 Ê¬ (75 ÉÃ´Ö³Ö¤Î 9 ¥×¥í¡¼¥ÖÊ¬) ·Ð²á¤¹¤ë¤È¥¢¥¤¥É¥ë¾õÂÖ¤ÎÀÜÂ³¤Ï½ªÎ»¤µ¤»¤é¤ì¤ë¡£

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tcp_low_latency (Boolean; default: disabled)

Í¸ú¤Ë¤¹¤ë¤È¡¢TCP ¥¹¥¿¥Ã¥¯¤Ï¥¹¥ë¡¼¥×¥Ã¥È¤ò¹â¤¯¤¹¤ë¤è¤ê¤â ÃÙ±ä¤ò¾¯¤Ê¤¯¤¹¤ë¤³¤È¤òÍ¥Àè¤·¤ÆÈ½ÃÇ¤ò¹Ô¤¦¡£ ¤³¤Î¥ª¥×¥·¥ç¥ó¤òÌµ¸ú¤Ë¤¹¤ë¤È¡¢¥¹¥ë¡¼¥×¥Ã¥È¤ò¹â¤¯¤¹¤ë¤³¤È¤¬Í¥Àè¤µ¤ì¤ë¡£ ¤³¤Î¥Ç¥Õ¥©¥ë¥ÈÃÍ¤òÊÑ¹¹¤·¤¿Êý¤¬¤è¤¤¥¢¥×¥ê¥±¡¼¥·¥ç¥ó¤ÎÎã¤È¤·¤Æ¤Ï Beowulf ¥³¥ó¥Ô¥å¡¼¥¿¥¯¥é¥¹¥¿¤¬µó¤²¤é¤ì¤ë¤À¤í¤¦¡£

tcp_max_orphans (integer; default: ²¼µ)

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tcp_max_syn_backlog (integer; default: ²¼µ)

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tcp_max_tw_buckets (integer; default: ²¼µ)

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tcp_mem

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pressure - TCP ¤¬¥¢¥í¥±¡¼¥È¤·¤¿¥á¥â¥ê¤¬¤³¤Î¿ôÃÍÊ¬¤Î¥Ú¡¼¥¸¿ô¤ò±Û¤¨¤ë¤È¡¢ TCP ¤Ï¥á¥â¥ê¾ÃÈñ¤òÍÞ¤¨¤ë¤è¤¦¤Ë¤Ê¤ë¡£ ¥¢¥í¥±¡¼¥È¤·¤¿¥Ú¡¼¥¸¿ô¤¬ low °Ê²¼¤Ë¤Ê¤ë¤È¡¢¤³¤Î¥á¥â¥ê°µÇ÷¾õÂÖ¤«¤éÃ¦¤¹¤ë¡£

tcp_orphan_retries (integer; default: 8)

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tcp_reordering (integer; default: 3)

TCP ¥Ñ¥±¥Ã¥È¥¹¥È¥ê¡¼¥à¤Ç¥Ñ¥±¥Ã¥È½ç½ø¤ÎµÕÅ¾¤¬È¯À¸¤·¤¿¤À¤±¤Ç¤¢¤ê¡¢ ¥Ñ¥±¥Ã¥È¥í¥¹¤¬µ¯¤³¤Ã¤¿¤È¤Ï¤ß¤Ê¤µ¤Ê¤¤¡¢¥Ñ¥±¥Ã¥È¿ô¤ÎºÇÂçÃÍ¡£ ¤³¤ÎÃÍ¤òÄ¶¤¨¤Æ¥Ñ¥±¥Ã¥È¤Î½ç½øµÕÅ¾¤¬µ¯¤³¤ë¤È¡¢¥Ñ¥±¥Ã¥È¥í¥¹¤¬À¸¤¸¤¿¤È ¤ß¤Ê¤·¡¢slow start ¤ËÆþ¤ë¡£ ¤³¤Î¿ôÃÍ¤ÏÊÑ¹¹¤·¤Ê¤¤¤Û¤¦¤¬ÎÉ¤¤¡£ ¤³¤ì¤Ï¡¢ÀÜÂ³Ãæ¤Î¥Ñ¥±¥Ã¥È¤ÎÊÂ¤ÓÂØ¤¨¤Ë¤è¤Ã¤ÆÀ¸¤¸¤ë ÉÔÉ¬Í×¤ÊÂ®ÅÙÄã²¼¤äºÆÁ÷¤òºÇ¾®²½¤¹¤ë¤è¤¦¤ËÀß·×¤µ¤ì¤¿¡¢ ¥Ñ¥±¥Ã¥ÈÊÂ¤ÓÂØ¤¨ (packet reordering) ¤Î¸¡ÃÎ¥á¥È¥ê¥Ã¥¯¤Ê¤Î¤Ç¤¢¤ë¡£

tcp_retrans_collapse (Boolean; default: enabled)

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tcp_retries1 (integer; default: 3)

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tcp_retries2 (integer; default: 15)

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tcp_rfc1337 (Boolean; default: disabled)

TCP ¤ÎÆ°ºî¤ò RFC 1337 ¤Ë½àµò¤µ¤»¤ë¡£ Ìµ¸ú¤Ë¤¹¤ë¤È¡¢TIME_WAIT ¾õÂÖ¤Î¤È¤¤Ë RST ¤¬¼õ¿®¤µ¤ì¤¿¾ì¹ç¡¢ TIME_WAIT ´ü´Ö¤Î½ªÎ»¤òÂÔ¤¿¤º¤Ë¤½¤Î¥½¥±¥Ã¥È¤òÄ¾¤Á¤Ë¥¯¥í¡¼¥º¤¹¤ë¡£

tcp_rmem

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default - TCP ¥½¥±¥Ã¥È¤Î¼õ¿®¥Ð¥Ã¥Õ¥¡¤Î¥Ç¥Õ¥©¥ë¥È¥µ¥¤¥º¡£ ¤³¤ÎÃÍ¤Ï¡¢¤¹¤Ù¤Æ¤Î¥×¥í¥È¥³¥ë¤ËÂÐ¤·¤ÆÄêµÁ¤µ¤ì¤Æ¤¤¤ë¡¢ ¥¸¥§¥Í¥ê¥Ã¥¯¤Ê¥°¥í¡¼¥Ð¥ë¤Î¥Ç¥Õ¥©¥ë¥È¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º net.core.rmem_default ¤è¤êÍ¥Àè¤µ¤ì¤ë¡£ ¥Ç¥Õ¥©¥ë¥ÈÃÍ¤Ï 87380 ¥Ð¥¤¥È¤Ç¡¢¥á¥â¥ê¤Î¾¯¤Ê¤¤¥·¥¹¥Æ¥à¤Ç¤Ï 43689 ¤Ë¤Þ¤Ç¸º¤é¤µ¤ì¤ë¡£ Âç¤¤Ê¼õ¿®¥Ð¥Ã¥Õ¥¡¥µ¥¤¥º¤¬É¬Í×¤Ê¾ì¹ç¤Ï¡¢ ¤³¤ÎÃÍ¤òÁý¤ä¤¹¤Ù¤¤Ç¤¢¤ë (¤¹¤Ù¤Æ¤Î¥½¥±¥Ã¥È¤Ë±Æ¶Á¤¹¤ë)¡£ Âç¤¤Ê TCP ¥¦¥£¥ó¥É¥¦¤òÍÑ¤¤¤ë¤Ë¤Ï¡¢ net.ipv4.tcp_window_scaling ¤òÍ¸ú¤Ë¤·¤Æ¤ª¤«¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤ (¥Ç¥Õ¥©¥ë¥È¤ÏÍ¸ú)¡£

max - ³Æ TCP ¥½¥±¥Ã¥È¤ÇÍÑ¤¤¤ë¼õ¿®¥Ð¥Ã¥Õ¥¡¤ÎºÇÂç¥µ¥¤¥º¡£ ¤³¤ÎÃÍ¤è¤ê¤â¥°¥í¡¼¥Ð¥ë¤Î net.core.rmem_max ¤¬Í¥Àè¤µ¤ì¤ë¡£ ¤³¤ì¤Ï¡¢ SO_RCVBUF ¤òÍÑ¤¤¤Æ¥½¥±¥Ã¥È¤Î¼õ¿®¥Ð¥Ã¥Õ¥¡¥µ¥¤¥ºÀ©¸Â¤òÀë¸À¤¹¤ëºÝ¤Ë¤ÏÍÑ¤¤¤é¤ì¤Ê¤¤¡£ ¥Ç¥Õ¥©¥ë¥ÈÃÍ¤Ï 87380*2 ¥Ð¥¤¥È¤Ç¡¢¥á¥â¥ê¤Î¾¯¤Ê¤¤¥·¥¹¥Æ¥à¤Ç¤Ï 87380 ¤Ë¤Þ¤Ç¸º¤é¤µ¤ì¤ë¡£

tcp_sack (Boolean; default: enabled)

RFC 2018 ¤Î TCP Selective Acknowledgements ¤òÍ¸ú¤Ë¤¹¤ë¡£

tcp_stdurg (Boolean; default: disabled)

tcp_synack_retries (integer; default: 5)

passive ¤Ê TCP ÀÜÂ³¤Î SYN/ACK ¥»¥°¥á¥ó¥È¤ÇºÆÁ÷¤ò»î¤ß¤ëºÇÂç¿ô¡£ ¤³¤Î¿ôÃÍ¤Ï 255 ¤è¤ê¤âÂç¤¤¯¤¹¤Ù¤¤Ç¤Ï¤Ê¤¤¡£

tcp_syncookies (Boolean)

CONFIG_SYNCOOKIES ¤ò¤Ä¤±¤Æ¥³¥ó¥Ñ¥¤¥ë¤·¤Æ¤ª¤«¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£ ¥½¥±¥Ã¥È¤Î¥Ð¥Ã¥¯¥í¥°¥¥å¡¼¤¬¥ª¡¼¥Ð¡¼¥Õ¥í¡¼¤¹¤ë¤È¡¢ syncookies ¤¬Á÷¿®¤µ¤ì¤ë¡£ syncookies µ¡Ç½¤Ï¡¢SYN flood ¹¶·â¤«¤é¥½¥±¥Ã¥È¤ò¼é¤í¤¦¤È¤¹¤ë¡£ ¤³¤ì¤Ï¤¤¤º¤ì¤Ë¤·¤Æ¤â¡¢ºÇ½ª¼êÃÊ¤È¤·¤ÆÍÑ¤¤¤ë¤Ù¤¤Ç¤¢¤ë¡£ ¤³¤ì¤Ï TCP ¥×¥í¥È¥³¥ë¤Ë°ãÈ¿¤·¤Æ¤ª¤ê¡¢ TCP ³ÈÄ¥¤Î¤è¤¦¤Ê¡¢TCP ¤ÎÂ¾¤ÎÉôÊ¬¤È¾×ÆÍ¤·¤Æ¤·¤Þ¤¦¡£ ¥¯¥é¥¤¥¢¥ó¥È¤ä¥ê¥ì¡¼¤ÇÌäÂê¤¬µ¯¤³¤ë¤³¤È¤â¤¢¤ë¡£ ²áÉé²Ù¤äÀßÄê´Ö°ã¤¤¤Ë¤è¤Ã¤ÆÉé²Ù¤ÎÂç¤¤Ê¾õÂÖ¤Ë¤¢¤ë¥µ¡¼¥Ð¤òÄ´À°¤·¤Æµß¤¦¤¿¤á¤Î µ¡¹½¤È¤ß¤Ê¤¹¤Ù¤¤Ç¤Ï¤Ê¤¤¡£ ¤½¤Î¤è¤¦¤ÊÍÑÅÓ¤Ë¤Ï¡¢Âå¤ï¤ê¤Ë tcp_max_syn_backlog, tcp_synack_retries, tcp_abort_on_overflow ¤Ê¤É¤Î»ÈÍÑ¤ò¹Í¤¨¤ë¤³¤È¡£

tcp_syn_retries (integer; default: 5)

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tcp_timestamps (Boolean; default: enabled)

RFC 1323 ¤Î TCP timestamps ¤òÍ¸ú¤Ë¤¹¤ë¡£

tcp_tw_recycle (Boolean; default: disabled)

TIME-WAIT ¥½¥±¥Ã¥È¤ÎÁÇÁá¤¤ºÆÍøÍÑ¤òÍ¸ú¤Ë¤¹¤ë¡£ ¤³¤Î¥ª¥×¥·¥ç¥ó¤òÍ¸ú¤Ë¤¹¤ë¤È¡¢ NAT (¥Í¥Ã¥È¥ï¡¼¥¯¥¢¥É¥ì¥¹ÊÑ´¹) ¤òÍÑ¤¤¤Æ¤¤¤ë¤ÈÌäÂê¤¬À¸¤¸¤ë¤Î¤Ç¡¢ ¤¢¤Þ¤ê¿ä¾©¤·¤Ê¤¤¡£

tcp_tw_reuse (Boolean; default: disabled)

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tcp_window_scaling (Boolean; default: enabled)

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tcp_vegas_cong_avoid (Boolean; default: disabled)

TCP Vegas íÕíÔÀ©¸æ¥¢¥ë¥´¥ê¥º¥à¤òÍ¸ú¤Ë¤¹¤ë¡£ TCP Vegas ¤ÏÂÓ°è¤ò¿äÂ¬¤¹¤ë¤³¤È¤ÇíÕíÔ¤Îµ¯¤³¤ê»Ï¤á¤òÍ½ÁÛ¤¹¤ë¤è¤¦¤Ë TCP ¤ÎÁ÷¿®Â¦¤Î¤ß¤ËÊÑ¹¹¤ò²Ã¤¨¤¿¤â¤Î¤Ç¤¢¤ë¡£ TCP Vegas ¤ÏíÕíÔ¥¦¥£¥ó¥É¥¦¤ò½¤Àµ¤¹¤ë¤³¤È¤Ç¡¢Á÷¿®¥ì¡¼¥È¤òÄ´À°¤¹¤ë¡£ TCP Vegas ¤Ï TCP Reno ¤ÈÈæ¤Ù¤Æ¥Ñ¥±¥Ã¥È¥í¥¹¤Ï¾¯¤Ê¤¤¤¬¡¢ TCP Reno ¤Û¤ÉÀÑ¶ËÅª¤ÊµóÆ°¤Ï¤·¤Ê¤¤¡£

tcp_westwood (Boolean; default: disabled)

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tcp_wmem

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ioctl

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int value;

error = ioctl(tcp_socket, ioctl_type, &value);

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accept(2), bind(2), connect(2), getsockopt(2), listen(2), recvmsg(2), sendfile(2), sendmsg(2), socket(2), sysctl(2), ip(7), socket(7)

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RFC 1122: TCP ¤ÎÍ×µá»ö¹à¤È Nagle ¥¢¥ë¥´¥ê¥º¥à¤Îµ½Ò¡£
RFC 1323: TCP ¤Î¥¿¥¤¥à¥¹¥¿¥ó¥×¡¦¥¦¥£¥ó¥É¥¦¥¹¥±¡¼¥ê¥ó¥°³Æ¥ª¥×¥·¥ç¥ó¡£
RFC 1644: TIME_WAIT assassination hazard ¤Ë´Ø¤¹¤ëµ½Ò¡£
RFC 3168: Explicit Congestion Notification ¤Ë´Ø¤¹¤ëµ½Ò¡£
RFC 2581: TCP íÕíÔÀ©¸æ¥¢¥ë¥´¥ê¥º¥à¡£
RFC 2018 ¤È RFC 2883: SACK ¤È¤½¤Î³ÈÄ¥¡£

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Toute la documentation sur la certification Linux LPI

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