.\" 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.
.\" $Id: udp.7,v 1.7 2000/01/22 01:55:05 freitag Exp $
.\"
.\" Japanese Version Copyright (c) 1999 NAKANO Takeo all rights reserved.
.\" Translated 1999-12-06, NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated 2005-10-09, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2007-01-05, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.43
.\" Updated 2008-12-29, Akihiro MOTOKI, LDP v3.14
.\"
.TH UDP  7 2008-11-21 "Linux" "Linux Programmer's Manual"
.SH ̾
udp \- IPv4  桼ǡץȥ
.SH 
.B #include <sys/socket.h>
.br
.B #include <netinet/in.h>
.sp
.B udp_socket = socket(AF_INET, SOCK_DGRAM, 0);
.SH 
 RFC\ 768 ǵҤƤ User Datagram Protocol μǤ롣
UDP ϥͥ쥹Ρ㤤ǡѥåȥӥǤ롣
ѥåȤ¤ؤ줿ʣ줿ꤹ롣
UDP ž顼򸡽Ф뤿˥åå롣

UDP åȤȤ
륢ɥ쥹⡼ȥɥ쥹ϻꤵʤ
Ԥ襢ɥ쥹Ȥ
.BR sendto (2)

.BR sendmsg (2)
Ƥ٤СǡϤ롣
åȤФ
.BR connect (2)
Ƥ֤ȡǥեȤιԤ襢ɥ쥹ꤵ졢
.BR send (2)

.BR write (2)
ȤäơԤ襢ɥ쥹λʤ˥ǡǤ褦ˤʤ롣
ξǤ⡢Ԥ襢ɥ쥹
.BR sendto (2)

.BR sendmsg (2)
ϤСǥեȰʳΥɥ쥹ǽǤ롣
ѥåȤ뤿ˡޤåȤ
.BR bind (2)
Ѥƥʥɥ쥹˥Хɤ뤳ȤǤ롣
ǤʤϡåؤϼưŪ
.I net.ipv4.ip_local_port_range
ƤϰϤγǶƤʥݡȤơ
åȤ
.B INADDR_ANY
˥Хɤ롣

ưϥѥåȤĤ֤ϤХåեѥåȤ
СΥѥåȤ礭Υǡ֤롣
դ˥Хåե礭ϥѥåȤϴݤ졢
.B MSG_TRUNC
ե饰åȤ롣
.B MSG_WAITALL
ϥݡȤƤʤ

IP ץϡ
.BR ip (7)
˵ҤƤ륽åȥץѤɤ߽񤭤Ǥ롣
Ŭڤ
/proc
ѥ᡼ͭʾ˸¤äƥͥˤäƽ
(̵ˤʤäƤǤ桼ˤϤ)
.BR ip (7)
򻲾ȤΤȡ

.B MSG_DONTROUTE
ե饰˥åȤƤˤϡ
Ԥ襢ɥ쥹ϥʥ󥿡եɥ쥹
ȤǤʤФʤʤѥåȤϤΥ󥿡եˤʤ

ǥեȤǤϡLinux  UDP  Path MTU Discovery Ԥ
Ĥޤꡢͥΰ IP ɥ쥹 MTU (Maximum Transmission Unit;
žñ) ϿUDP ѥåȤν񤭹ߤ MTU Ķ
.B EMSGSIZE
֤
.B EMSGSIZE
֤줿硢ץꥱϥѥåȥ򾮤٤Ǥ롣
åȥץ
.B IP_MTU_DISCOVER
ޤ
.I /proc/sys/net/ipv4/ip_no_pmtu_disc
եȤä Path MTU Discovery ̵ˤ뤳ȤǤ
(ܺ٤
.BR ip (7)
򻲾)
Path MTU Discovery ̵ˤϡѥåȥ
󥿥ե MTU 礭 UDP ϤΥѥåȤ
ե饰ȲФ롣
ʤ顢ǽȿͳ Path MTU Discovery 
̵ˤΤϿ侩Ǥʤ
.SS ɥ쥹Υեޥå
UDP  IPv4 
.I sockaddr_in
ɥ쥹եޥåȤѤ롣
.BR ip (7)
˵ҤƤ롣
.SS 顼
̿Ūʥ顼ϡȤåȤ³ƤʤƤ⡢
٤ƥ顼ͤȤƥ桼Ϥ롣
ˤϥͥåȥƱ顼ޤޤ롣
ƱåȤȤäΤΥѥåȤ˴ؤ륨顼뤫⤷ʤ
ο񤤤¾ BSD åȤμ¿Ȥϰۤʤ롣
ǤϥåȤ³Ƥʤϥ顼֤ʤ
Linux ο񤤤
.B RFC\ 1122
Ǥλ˽äΤǤ롣

Linux 2.0  2.2 ǤϡŤɤȤθߴΤˡ
.B SO_BSDCOMPAT
.B SOL_SOCKET
ץꤹСåȤ³Ƥ
˸¤äƥ⡼ȤΥ顼褦ˤǤ
.RB ( EPROTO "  " EMSGSIZE
)
줿顼ϾϤ롣
ΥåȥץΥݡȤϤʹߤΥС Linux 
줿ܺ٤
.BR socket (7)
򻲾ȡ

.B IP_RECVERR
ץͭˤʤäƤȡ
٤ƤΥ顼ϥåȤΥ顼塼¸롣

.B MSG_ERRQUEUE
ե饰򥻥åȤ
.BR recvmsg (2)
Ƥ٤мǤ롣
.SS /proc 󥿥ե
ƥΤ UDP ѥ᡼ˤϡ
.I /proc/sys/net/ipv4/
ǥ쥯ȥΥեɤ߽񤭤ǥǤ롣
.TP
.IR udp_mem " (Linux 2.6.25 ʹ)"
 3 Ĥʤ٥ȥͤǡ
UDP åȤΥ塼Ѳǽʥڡ椹롣
.RS
.TP 10
.I min
Υڡ꾯ʤСUDP ϤΥѤ˴ؤ
Ĥʤ
UDP ˳Ƥ줿̤ͤĶ᤹ȡ
UDP ϥ̤ĴϤ롣
.TP
.I pressure
ͤ
.I tcp_mem
η
.RB ( tcp (7)
) ȹ碌뤿Ƴ줿
.TP
.I max
UDP åȤΥ塼Ѳǽʥڡ
.RE
.IP
 3 ĤͤΥǥեͤϡ
֡ȻѲǽʥ̤׻롣
.TP
.IR udp_rmem_min " (integer; ǥե: PAGE_SIZE; Linux 2.6.25 ʹ)"
̤ĴˡUDP åȤѤǤХåեκǾ
(Хñ)
UDP åȤΥڡ̤ιפ
.I udp_mem
pressure ĶᤷƤǤäƤ⡢
 UDP åȤϥǡμˤΥʬϻѤ뤳ȤǤ롣
.TP
.IR udp_wmem_min " (integer; ǥե: PAGE_SIZE; Linux 2.6.25 ʹ)"
̤ĴˡUDP åȤѤǤХåեκǾ
(Хñ)
UDP åȤΥڡ̤ιפ
.I udp_mem
pressure ĶᤷƤǤäƤ⡢
 UDP åȤϥǡˤΥʬϻѤ뤳ȤǤ롣
.SS åȥץ
UDP åȥץޤϼˤϡ
ˤ
.BR getsockopt (2)
ˤ
.BR setsockopt (2)
򥪥ץ٥
.B IPPROTO_UDP
ꤷƸƤӽФ
.TP
.BR UDP_CORK " (Linux 2.5.44 ʹ)"
Υץ󤬻ꤵȡΥåȤƤΥǡϤ
ĤΥǡѤ졢Υץ̵줿
롣
ΥץϰܿθɤǤѤ٤ǤϤʤ
.\" FIXME document UDP_ENCAP (new in kernel 2.5.67)
.\" From include/linux/udp.h:
.\" /* UDP encapsulation types */
.\" #define UDP_ENCAP_ESPINUDP_NON_IKE      1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
.\" #define UDP_ENCAP_ESPINUDP      2 /* draft-ietf-ipsec-udp-encaps-06 */
.\" #define UDP_ENCAP_L2TPINUDP     3 /* rfc2661 */
.SS ioctl
ʲ˼ ioctl 
.BR ioctl (2)
ȤäƥǤ롣
ʸˡϰʲ̤ꡣ
.PP
.RS
.nf
.BI int " value";
.IB error " = ioctl(" udp_socket ", " ioctl_type ", &" value ");"
.fi
.RE
.TP
.BR FIONREAD " (" SIOCINQ )
integer Υݥ󥿤ȤƼ롣
ԵƤǡΥХñ̤֤
ԵƤǡबʤ 0 ֤
.TP
.BR TIOCOUTQ " (" SIOCOUTQ )
塼ˤǡХñ̤֤
Linux 2.4 ʾǤΤбƤ롣
.PP
ˡ
.BR ip (7)

.BR socket (7)
ǽҤ٤ƤƤ ioctl бƤ롣
.SH 顼
.BR socket (7)

.BR ip (7)
˵ҤƤƤΥ顼
UDP åȤ֤ǽ롣
.TP
.B ECONNREFUSED
Ԥ襢ɥ쥹˴ϢŤƤԤʤ
ϰΥѥåȤΥѥåȤ
ƤޤäƤ뤫Ǥ뤳Ȥ¿
.SH С
.B IP_RECVERR
 Linux 2.2 οǽǤ롣
.\" .SH 
.\"  man ڡ Andi Kleen 񤤤
.SH Ϣ
.BR ip (7),
.BR raw (7),
.BR socket (7),
.BR udplite (7)

RFC\ 768 : User Datagram Protocol
.br
RFC\ 1122 : ۥȤɬ׾
.br
RFC\ 1191 : path MTU discovery ε