[linuxjm/LDP_man-pages.git] / draft / man7 / udplite.7

.\" Copyright (c) 2008 by Gerrit Renker <gerrit@erg.abdn.ac.uk>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" $Id: udplite.7,v 1.12 2008/07/23 15:22:22 gerrit Exp gerrit $
.\"
.\" Japanese Version Copyright (c) 2008  Akihiro MOTOKI
.\"         all rights reserved.
.\" Translated 2008-08-21, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.07
.\" 
.TH UDPLITE  7 2008-12-03 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O udplite \- Lightweight User Datagram Protocol
udplite \- ·ÚÎ̤ʥ桼¥¶¡¼¥Ç¡¼¥¿¥°¥é¥à¥×¥í¥È¥³¥ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <sys/socket.h>
.br
.\" FIXME . see #defines under `BUGS',
.\"        when glibc supports this, add
.\"        #include <netinet/udplite.h>
.sp
.B sockfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDPLITE);
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O This is an implementation of the Lightweight User Datagram Protocol
.\"O (UDP-Lite), as described in RFC\ 3828.
¤³¤ì¤Ï RFC\ 3828 ¤Ë½ñ¤«¤ì¤Æ¤¤¤ë·ÚÎ̤ʥ桼¥¶¡¼¥Ç¡¼¥¿¥°¥é¥à¥×¥í¥È¥³¥ë
(Lightweight User Datagram Protocol; UDP-Lite) ¤Î¼ÂÁõ¤Ç¤¢¤ë¡£

.\"O UDP-Lite is an extension of UDP (RFC\ 768) to support variable-length
.\"O checksums.
.\"O This has advantages for some types of multimedia transport that
.\"O may be able to make use of slightly damaged datagrams,
.\"O rather than having them discarded by lower-layer protocols.
UDP-Lite ¤Ï UDP (RFC\ 768) ¤Î³ÈÄ¥¤Ç¡¢²ÄÊÑĹ¤Î¥Á¥§¥Ã¥¯¥µ¥à¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤ë¡£
¤³¤Î¥×¥í¥È¥³¥ë¤¬¸ú²Ì¤òȯ´ø¤¹¤ë¤Î¤Ï¡¢¾¯¤·¤À¤±²õ¤ì¤¿¥Ç¡¼¥¿¥°¥é¥à¤¬¤¢¤Ã¤¿¾ì¹ç¤Ë¡¢
¤½¤Î¥Ç¡¼¥¿¥°¥é¥à¤ò²¼°Ì¥ì¥¤¥ä¡¼¤Î¥×¥í¥È¥³¥ë¤ËÇÑ´þ¤µ¤»¤ë¤Î¤Ç¤Ï¤Ê¤¯¡¢
¤½¤ì¤òÍøÍѤ¹¤ë¤³¤È¤¬¤Ç¤­¤ë¤è¤¦¤Ê¡¢¤¢¤ë¼ï¤Î¥Þ¥ë¥Á¥á¥Ç¥£¥¢Å¾Á÷¤Ë¤ª¤¤¤Æ¤Ç¤¢¤ë¡£

.\"O The variable-length checksum coverage is set via a
.\"O .BR setsockopt (2)
.\"O option.
.\"O If this option is not set, the only difference to UDP is
.\"O in using a different IP protocol identifier (IANA number 136).
²ÄÊÑĹ¤Î¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоÝÈϰϤÏ
.BR setsockopt (2)
¥ª¥×¥·¥ç¥ó·Ðͳ¤ÇÀßÄꤵ¤ì¤ë¡£
¤³¤Î¥ª¥×¥·¥ç¥ó¤¬ÀßÄꤵ¤ì¤Æ¤¤¤Ê¤¤¾ì¹ç¡¢UDP ¤È°Û¤Ê¤ë¤Î¤Ï
°ã¤¦ IP ¥×¥í¥È¥³¥ë¼±ÊÌ»Ò (IANA ÈÖ¹æ 136) ¤ò»ÈÍѤ¹¤ëÅÀ¤À¤±¤Ç¤¢¤ë¡£

.\"O The UDP-Lite implementation is a full extension of
.\"O .BR udp (7),
.\"O i.e., it shares the same API and API behaviour, and in addition
.\"O offers two socket options to control the checksum coverage.
UDP-Lite ¤Î¼ÂÁõ¤Ï
.BR udp (7)
¤Î´°Á´¤Ê³ÈÄ¥¡¢¤¹¤Ê¤ï¤Á API ¤È API ¤ÎÆ°ºî¤ÏƱ¤¸¤Ç¤¢¤ë¡£
¤³¤ì¤Ë²Ã¤¨¤Æ¡¢2 ¤Ä¤Î¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤¬¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоÝÈϰϤò
À©¸æ¤¹¤ë¤¿¤á¤ËÄ󶡤µ¤ì¤Æ¤¤¤ë¡£
.\"O .SS "Address Format"
.SS ¥¢¥É¥ì¥¹¤Î¥Õ¥©¡¼¥Þ¥Ã¥È
.\"O UDP-Litev4 uses the
.\"O .I sockaddr_in
.\"O address format described in
.\"O .BR ip (7).
.\"O UDP-Litev6 uses the
.\"O .I sockaddr_in6
.\"O address format described in
.\"O .BR ipv6 (7).
UDP-Litev4 ¤Ï
.BR ip (7)
¤ÇÀâÌÀ¤µ¤ì¤Æ¤¤¤ë
.I sockaddr_in
¥¢¥É¥ì¥¹¤ò»ÈÍѤ¹¤ë¡£
UDP-Litev6 ¤Ï
.BR ipv6 (7)
¤ÇÀâÌÀ¤µ¤ì¤Æ¤¤¤ë
.I sockaddr_in6
¥¢¥É¥ì¥¹¤ò»ÈÍѤ¹¤ë¡£
.\"O .SS "Socket Options"
.SS ¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó
.\"O To set or get a UDP-Lite socket option, call
.\"O .BR getsockopt (2)
.\"O to read or
.\"O .BR setsockopt (2)
.\"O to write the option with the option level argument set to
.\"O .BR IPPROTO_UDPLITE .
.\"O In addition, all
.\"O .B IPPROTO_UDP
.\"O socket options are valid on a UDP-Lite socket.
.\"O See
.\"O .BR udp (7)
.\"O for more information.
UDP-Lite ¤Î¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤òÀßÄê/¼èÆÀ¤¹¤ë¤Ë¤Ï¡¢
¥ª¥×¥·¥ç¥ó¥ì¥Ù¥ë°ú¤­¿ô¤Ë
.B IPPROTO_UDPLITE
¤ò»ØÄꤷ¤Æ¡¢¼èÆÀ»þ¤Ë¤Ï
.BR getsockopt (2)
¤ò¡¢ÀßÄê»þ¤Ë¤Ï
.BR setsockopt (2)
¤ò¸Æ¤Ó½Ð¤¹¡£¤µ¤é¤Ë¡¢Á´¤Æ¤Î
.B IPPROTO_UDP
¤Î¥½¥±¥Ã¥È¥ª¥×¥·¥ç¥ó¤¬ UDP-Lite ¥½¥±¥Ã¥È¤Ç¤â»ÈÍѤǤ­¤ë¡£
¾ÜºÙ¤Ï
.BR udp (7)
¤ò»²¾È¤Î¤³¤È¡£

.\"O The following two options are specific to UDP-Lite.
°Ê²¼¤Î 2 ¤Ä¤¬ UDP-Lite ¤Ë¸ÇÍ­¤Î¥ª¥×¥·¥ç¥ó¤Ç¤¢¤ë¡£
.TP
.BR UDPLITE_SEND_CSCOV
.\"O This option sets the sender checksum coverage and takes an
.\"O .I int
.\"O as argument, with a checksum coverage value in the range 0..2^16-1.
¤³¤Î¥ª¥×¥·¥ç¥ó¤ÏÁ÷¿®Â¦¤Î¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоÝÈϰϤòÀßÄꤹ¤ë¡£
.I int
·¿¤ò°ú¤­¿ô¤È¤·¤Æ¼è¤ê¡¢ÀßÄê²Äǽ¤ÊÃͤÎÈÏ°Ï¤Ï 0 ¤«¤é 2^16-1 ¤Þ¤Ç¤Ç¤¢¤ë¡£

.\"O A value of 0 means that the entire datagram is always covered.
.\"O Values from 1-7 are illegal (RFC\ 3828, 3.1) and are rounded up to
.\"O the minimum coverage of 8.
ÃÍ 0 ¤Ï¥Ç¡¼¥¿¥°¥é¥àÁ´ÂΤ¬¾ï¤Ë¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоݤȤʤ뤳¤È¤ò°ÕÌ£¤¹¤ë¡£
ÃÍ 1¡Á7 ¤ÏÉÔÀµ¤Ç¤¢¤ê (RFC\ 3828 ¤Î 3.1 ¾Ï)¡¢ÈϰϤÎÀßÄê¤È¤·¤ÆºÇ¾®ÃͤǤ¢¤ë
8 ¤ËÀÚ¤ê¾å¤²¤é¤ì¤ë¡£

.\"O With regard to IPv6 jumbograms (RFC\ 2675), the UDP-Litev6 checksum
.\"O coverage is limited to the first 2^16-1 octets, as per RFC\ 3828, 3.5.
.\"O Higher values are therefore silently truncated to 2^16-1.
.\"O If in doubt, the current coverage value can always be queried using
.\"O .BR getsockopt (2).
IPv6 ¤Î jumbograms (µðÂç¤Ê¥Ç¡¼¥¿¥°¥é¥à; RFC\ 2675) ¤Î¾ì¹ç¤Ë¤Ï¡¢
UDP-Litev6 ¤Î¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоÝÈϰϤϡ¢RFC\ 3828 ¤Î 3.5 ¾Ï¤Ë¤¢¤ë¤è¤¦¤Ë¡¢
ÀèƬ¤«¤é 2^16-1 ¥ª¥¯¥Æ¥Ã¥È¤Þ¤Ç¤Ë¸ÂÄꤵ¤ì¤ë¡£
¤½¤Î¤¿¤á¡¢¤½¤ì¤è¤êÂ礭¤ÊÃÍ¤Ï 2^16-1 ¤ËÌۤäÆÀÚ¤êµÍ¤á¤é¤ì¤ë¡£
¸½ºß¤ÎÂоÝÈϰϤÎÃͤòÃΤꤿ¤±¤ì¤Ð¡¢¤¤¤Ä¤Ç¤â
.BR getsockopt (2)
¤ò»È¤Ã¤ÆÃͤòÌ䤤¹ç¤ï¤»¤ë¤³¤È¤¬¤Ç¤­¤ë¡£
.TP
.BR UDPLITE_RECV_CSCOV
.\"O This is the receiver-side analogue and uses the same argument format
.\"O and value range as
.\"O .BR UDPLITE_SEND_CSCOV .
.\"O This option is not required to enable traffic with partial checksum
.\"O coverage.
.\"O Its function is that of a traffic filter: when enabled, it
.\"O instructs the kernel to drop all packets which have a coverage
.\"O .I less
.\"O than the specified coverage value.
¤³¤ì¤Ï¼õ¿®Â¦¤Î¥Á¥§¥Ã¥¯¥µ¥à¤ÎÂоÝÈϰϤòÀßÄꤹ¤ë¤â¤Î¤Ç¡¢
»ÈÍѤµ¤ì¤ë°ú¤­¿ô·Á¼°¤ÈÃͤÎÈϰϤÏ
.B UDPLITE_SEND_CSCOV
¤ÈƱ¤¸¤Ç¤¢¤ë¡£
¤³¤Î¥ª¥×¥·¥ç¥ó¤Ï¡¢ÉôʬŪ¤Ê¥Á¥§¥Ã¥¯¥µ¥àÂоÝÈϰϤò»ý¤Ä¥È¥é¥Õ¥£¥Ã¥¯¤ò
Í­¸ú¤Ë¤¹¤ë¤Î¤ËɬÍפʤ櫓¤Ç¤Ï¤Ê¤¯¡¢¥È¥é¥Õ¥£¥Ã¥¯¥Õ¥£¥ë¥¿¡¼¤È¤·¤Æµ¡Ç½¤¹¤ë¡£
¤³¤Î¥ª¥×¥·¥ç¥ó¤¬Í­¸ú¤Ë¤¹¤ë¤È¡¢¥«¡¼¥Í¥ë¤Ï»ØÄꤵ¤ì¤¿¥Á¥§¥Ã¥¯¥µ¥àÂоÝÈÏ°Ï
¤è¤ê¤â¡Öû¤«¤¤¡×ÂоÝÈϰϤò»ý¤Ä¥Ñ¥±¥Ã¥È¤òÁ´¤ÆÇÑ´þ¤¹¤ë¤è¤¦¤Ë¤Ê¤ë¡£

.\"O When the value of
.\"O .B UDPLITE_RECV_CSCOV
.\"O exceeds the actual packet coverage, incoming packets are silently dropped,
.\"O but may generate a warning message in the system log.
.B UDPLITE_RECV_CSCOV
¤ÎÃͤ¬¼ÂºÝ¤Î¥Ñ¥±¥Ã¥È¤Î¥Á¥§¥Ã¥¯¥µ¥àÂоÝÈϰϤè¤ê¤âÂ礭¤¤¾ì¹ç¡¢
¼õ¿®¤·¤¿¥Ñ¥±¥Ã¥È¤ÏÌۤäÆÇÑ´þ¤µ¤ì¤ë¡£
¤¿¤À¤·¡¢¥·¥¹¥Æ¥à¥í¥°¤ËÂФ·¤Æ·Ù¹ð¥á¥Ã¥»¡¼¥¸¤¬À¸À®¤µ¤ì¤ë¤«¤â¤·¤ì¤Ê¤¤¡£
.\" SO_NO_CHECK exists and is supported by UDPv4, but is
.\" commented out in socket(7), hence also commented out here
.\".PP
.\"Since UDP-Lite mandates checksums, checksumming can not be disabled
.\"via the
.\".B SO_NO_CHECK
.\"option from
.\".BR socket (7).
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.\"O All errors documented for
.\"O .BR udp (7)
.\"O may be returned.
.\"O UDP-Lite does not add further errors.
.BR udp (7)
¤Ë¤Ä¤¤¤Æ½ñ¤«¤ì¤Æ¤¤¤ëÁ´¤Æ¤Î¥¨¥é¡¼¤ÏÊÖ¤ë²ÄǽÀ­¤¬¤¢¤ë¡£
UDP-Lite ¼«ÂΤϿ·¤¿¤Ê¥¨¥é¡¼¤ÏÄɲ䷤Ƥ¤¤Ê¤¤¡£
.\"O .SH BUGS
.SH ¥Ð¥°
.\" FIXME . remove this section once glibc supports UDP-Lite
.\"O Where glibc support is missing, the following definitions are needed:
glibc ¤Ë¤è¤ë¥µ¥Ý¡¼¥È¤¬¤Ê¤¤¾ì¹ç¤Ï¡¢°Ê²¼¤ÎÄêµÁ¤ò¹Ô¤¦É¬Íפ¬¤¢¤ë¡£
.in +4n
.nf

#define IPPROTO_UDPLITE     136
.\" The following two are defined in the kernel in linux/net/udplite.h
#define UDPLITE_SEND_CSCOV  10
#define UDPLITE_RECV_CSCOV  11
.fi
.in
.\"O .SH FILES
.SH ¥Õ¥¡¥¤¥ë
.I /proc/net/snmp
.\"O \- basic UDP-Litev4 statistics counters.
\- UDP-Litev4 ¤Î´ðËÜŪ¤ÊÅý·×¾ðÊ󥫥¦¥ó¥¿¡¼¡£
.br
.I /proc/net/snmp6
.\"O \- basic UDP-Litev6 statistics counters.
\- UDP-Litev6 ¤Î´ðËÜŪ¤ÊÅý·×¾ðÊ󥫥¦¥ó¥¿¡¼¡£
.\"O .SH VERSIONS
.SH ¥Ð¡¼¥¸¥ç¥ó
.\"O UDP-Litev4/v6 first appeared in Linux 2.6.20.
UDP-Litev4/v6 ¤Ï Linux 2.6.20 ¤Ç½é¤á¤ÆÅо줷¤¿¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR udp (7),
.BR ip (7),
.BR ipv6 (7),
.BR socket (7)

RFC\ 3828 for the Lightweight User Datagram Protocol (UDP-Lite)
.br
.I Documentation/networking/udplite.txt