'\" '\" Generated from file './doc/udp.man' by tcllib/doctools with format 'nroff' '\" Copyright (c) 1999-2000 Columbia University; all rights reserved '\" .\" The -*- nroff -*- definitions below are for supplemental macros used .\" in Tcl/Tk manual entries. .\" .\" .AP type name in/out ?indent? .\" Start paragraph describing an argument to a library procedure. .\" type is type of argument (int, etc.), in/out is either "in", "out", .\" or "in/out" to describe whether procedure reads or modifies arg, .\" and indent is equivalent to second arg of .IP (shouldn't ever be .\" needed; use .AS below instead) .\" .\" .AS ?type? ?name? .\" Give maximum sizes of arguments for setting tab stops. Type and .\" name are examples of largest possible arguments that will be passed .\" to .AP later. If args are omitted, default tab stops are used. .\" .\" .BS .\" Start box enclosure. From here until next .BE, everything will be .\" enclosed in one large box. .\" .\" .BE .\" End of box enclosure. .\" .\" .CS .\" Begin code excerpt. .\" .\" .CE .\" End code excerpt. .\" .\" .VS ?version? ?br? .\" Begin vertical sidebar, for use in marking newly-changed parts .\" of man pages. The first argument is ignored and used for recording .\" the version when the .VS was added, so that the sidebars can be .\" found and removed when they reach a certain age. If another argument .\" is present, then a line break is forced before starting the sidebar. .\" .\" .VE .\" End of vertical sidebar. .\" .\" .DS .\" Begin an indented unfilled display. .\" .\" .DE .\" End of indented unfilled display. .\" .\" .SO ?manpage? .\" Start of list of standard options for a Tk widget. The manpage .\" argument defines where to look up the standard options; if .\" omitted, defaults to "options". The options follow on successive .\" lines, in three columns separated by tabs. .\" .\" .SE .\" End of list of standard options for a Tk widget. .\" .\" .OP cmdName dbName dbClass .\" Start of description of a specific option. cmdName gives the .\" option's name as specified in the class command, dbName gives .\" the option's name in the option database, and dbClass gives .\" the option's class in the option database. .\" .\" .UL arg1 arg2 .\" Print arg1 underlined, then print arg2 normally. .\" .\" .QW arg1 ?arg2? .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). .\" .\" .PQ arg1 ?arg2? .\" Print an open parenthesis, arg1 in quotes, then arg2 normally .\" (for trailing punctuation) and then a closing parenthesis. .\" .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b .\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. .\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out .\" # BS - start boxed text .\" # ^y = starting y location .\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. .\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. .\" # VS - start vertical sidebar .\" # ^Y = starting y location .\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. .\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. .\" # Special macro to handle page bottom: finish off current .\" # box/sidebar if in box/sidebar mode, then invoked standard .\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. .\" # DS - begin display .de DS .RS .nf .sp .. .\" # DE - end display .de DE .fi .RE .sp .. .\" # SO - start of list of standard options .de SO 'ie '\\$1'' .ds So \\fBoptions\\fR 'el .ds So \\fB\\$1\\fR .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. .\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\*(So manual entry for details on the standard options. .. .\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. .\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. .\" # CE - end code excerpt .de CE .fi .RE .. .\" # UL - underline word .de UL \\$1\l'|0\(ul'\\$2 .. .\" # QW - apply quotation marks to word .de QW .ie '\\*(lq'"' ``\\$1''\\$2 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\$2 .. .\" # PQ - apply parens and quotation marks to word .de PQ .ie '\\*(lq'"' (``\\$1''\\$2)\\$3 .\"" fix emacs highlighting .el (\\*(lq\\$1\\*(rq\\$2)\\$3 .. .\" # QR - quoted range .de QR .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 .. .\" # MT - "empty" string .de MT .QW "" .. .TH "udp" 3tcl 1.0.11 udp "Tcl UDP extension" .BS .SH NAME udp \- Create UDP sockets in Tcl .SH SYNOPSIS package require \fBTcl 8.2\fR .sp package require \fBudp 1.0.11\fR .sp \fBudp_open\fR ?\fIport\fR? ?\fIreuse\fR? ?\fIipv6\fR? .sp \fBudp_conf\fR \fIsock\fR \fIhost\fR \fIport\fR .sp \fBudp_conf\fR \fIsock\fR \fI?-myport?\fR \fI?-remote?\fR \fI?-peer?\fR \fI?-broadcast bool?\fR \fI?-ttl count?\fR \fI?-mcastadd "groupaddr ?netwif?"?\fR \fI?-mcastdrop "groupaddr ?netwif?"?\fR \fI?-mcastgroups?\fR \fI?-mcastloop bool?\fR .sp \fBudp_peek\fR \fIsock\fR ?\fIbuffersize\fR? .sp .BE .SH DESCRIPTION This package provides support for using UDP through Tcl. The package provides a new channel type and attempts to permit the use of packet oriented UDP over stream oriented Tcl channels. The package defined three commands but \fBudp_conf\fR should be considered depreciated in favour of the standard Tcl command \fBfconfigure\fR. .SH COMMANDS .TP \fBudp_open\fR ?\fIport\fR? ?\fIreuse\fR? ?\fIipv6\fR? \fBudp_open\fR will open a UDP socket. If a \fIport\fR is specified the UDP socket will be opened on that port. Otherwise the system will choose a port and the user can use the \fBudp_conf\fR command to obtain the port number if required. .sp The following keywords can be used to specify options on the opened socket. .RS .TP \fIreuse\fR Using this keyword sets the SO_REUSEADDR socket option which permits multiple sockets to be bound to the same address/port combination. .TP \fIipv6\fR By default a IPv4 socket is created. When keyword \fIipv6\fR is specified an IPv6 socket is opened. .RE .TP \fBudp_conf\fR \fIsock\fR \fIhost\fR \fIport\fR \fIDeprecated\fR in favour of the standard Tcl \fBfconfigure\fR command. .sp \fBudp_conf\fR in this configuration is used to specify the remote destination for packets written to this \fIsock\fR. You must call this command before writing data to the UDP socket. .TP \fBudp_conf\fR \fIsock\fR \fI?-myport?\fR \fI?-remote?\fR \fI?-peer?\fR \fI?-broadcast bool?\fR \fI?-ttl count?\fR \fI?-mcastadd "groupaddr ?netwif?"?\fR \fI?-mcastdrop "groupaddr ?netwif?"?\fR \fI?-mcastgroups?\fR \fI?-mcastloop bool?\fR \fIDeprecated\fR in favour of the standard Tcl \fBfconfigure\fR command. .sp In addition to being used to configure the remote host, the \fBudp_conf\fR command is used to obtain information about the UDP socket. NOTE all these options are now available using the standard Tcl \fBfconfigure\fR command. .RS .TP \fI-myport\fR Returns the local port number of the socket. .TP \fI-remote\fR Returns the remote hostname and port number as set using \fBudp_conf\fR \fIsock\fR \fIhost\fR \fIport\fR. .TP \fI-peer\fR Returns the remote hostname and port number for the packet most recently received by this socket. .TP \fI-broadcast ?boolean?\fR UDP packets can listen and send on the broadcast address. For some systems a flag must be set on the socket to use broadcast. With no argument this option will return the broadcast setting. With a boolean argument the setting can be modified. This option is not permitted when using IPv6. .TP \fI-ttl ?count?\fR The time-to-live is given as the number of router hops the packet may do. For multicast packets this is important in specifying the distribution of the packet. The system default for multicast is 1 which restricts the packet to the local subnet. To permit packets to pass routers, you must increase the ttl. A value of 31 should keep it within a site, while 255 is global. .TP \fI-mcastadd\fR groupaddr .TP \fI-mcastadd\fR "groupaddr netwif" .TP \fI-mcastdrop\fR groupaddr .TP \fI-mcastdrop\fR "groupaddr netwif" .TP \fI-mcastgroups\fR \fBtcludp\fR sockets can support IPv4 and IPv6 multicast operations. To receive multicast packets the application has to notify the operating system that it should join a particular multicast group. For IPv4 these are specified as addresses in the range 224.0.0.0 to 239.255.255.255. .sp When specifying only the \fIgroupaddr\fR the system will determine the network interface to use. Specifying the \fInetwif\fR will join a multicast group on a specific network interface. This is useful on a multihomed system with multiple network interfaces. On windows you must specify the network interface index. For other platforms the network interface (e.g. 'eth0') name can be specified. .sp To view the current set of multicast groups for a channel use \fI-mcastgroups\fR .TP \fI-mcastloop ?boolean?\fR With multicast udp the system can choose to receive packets that it has sent or it can drop them. This is known as multicast loopback and can be controlled using this option. By default the value is true and your application will receive its own transmissions. .RE .TP \fBudp_peek\fR \fIsock\fR ?\fIbuffersize\fR? Examine a packet without removing it from the buffer. Option \fIbuffersize\fR specifies the maximum buffer size. Value must be between 0 and 16. .sp This function is not available on windows. .PP .SH EXAMPLES .PP .nf # Send data to a remote UDP socket proc udp_puts {host port} { set s [udp_open] fconfigure $s -remote [list $host $port] puts $s "Hello, World" close $f } .fi .nf # A simple UDP server package require udp proc udpEventHandler {sock} { set pkt [read $sock] set peer [fconfigure $sock -peer] puts "$peer: [string length $pkt] {$pkt}" return } proc udp_listen {port} { set srv [udp_open $port] fconfigure $srv -buffering none -translation binary fileevent $srv readable [list ::udpEventHandler $srv] puts "Listening on udp port: [fconfigure $srv -myport]" return $srv } set sock [udp_listen 53530] vwait forever close $sock .fi .nf # A multicast demo. proc udpEvent {chan} { set data [read $chan] set peer [fconfigure $chan -peer] puts "$peer [string length $data] '$data'" if {[string match "QUIT*" $data]} { close $chan set ::forever 1 } return } set group 224.5.1.21 set port 7771 set s [udp_open $port] fconfigure $s -buffering none -blocking 0 fconfigure $s -mcastadd $group -remote [list $group $port] fileevent $s readable [list udpEvent $s] puts -nonewline $s "hello, world" set ::forever 0 vwait ::forever exit .fi .SH HISTORY Some of the code in this extension is copied from Michael Miller's tcludp package. (http://www.neosoft.com/tcl/ftparchive/sorted/comm/tcludp-1.0/) Compared with Michael's UDP extension, this extension provides Windows support and provides the ability of using 'gets/puts' to read/write the socket. In addition, it provides more configuration ability. .PP Enhancements to support binary data and to setup the package for the Tcl Extension Architecture by Pat Thoyts. .PP Support for IPv6 and allowing a multicast join on a specific network interface is added by Huub Eikens. .SH "SEE ALSO" socket(3tcl) .SH KEYWORDS networking, socket, udp .SH COPYRIGHT .nf Copyright (c) 1999-2000 Columbia University; all rights reserved .fi