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| author | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-15 23:08:59 +0000 |
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| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2014-12-15 23:08:59 +0000 |
| commit | e0fc82203d677a6f1e808e9a1a46176c109d89be (patch) | |
| tree | e9609209b755e3f7a8480aea86601ffe9d4ca540 /doc/s6-tcpclient.html | |
| download | s6-networking-e0fc82203d677a6f1e808e9a1a46176c109d89be.tar.xz | |
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| -rw-r--r-- | doc/s6-tcpclient.html | 133 |
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diff --git a/doc/s6-tcpclient.html b/doc/s6-tcpclient.html new file mode 100644 index 0000000..42edaa9 --- /dev/null +++ b/doc/s6-tcpclient.html @@ -0,0 +1,133 @@ +<html> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> + <meta http-equiv="Content-Language" content="en" /> + <title>s6-networking: the s6-tcpclient program</title> + <meta name="Description" content="s6-networking: the s6-tcpclient program" /> + <meta name="Keywords" content="s6-networking s6-tcpclient tcpclient ucspi tcp inet network tcp/ip client" /> + <!-- <link rel="stylesheet" type="text/css" href="http://skarnet.org/default.css" /> --> + </head> +<body> + +<p> +<a href="index.html">s6-networking</a><br /> +<a href="http://skarnet.org/software/">Software</a><br /> +<a href="http://skarnet.org/">skarnet.org</a> +</p> + +<h1> The <tt>s6-tcpclient</tt> program </h1> + +<p> +<tt>s6-tcpclient</tt> is an +<a href="http://cr.yp.to/proto/ucspi.txt">UCSPI client tool</a> for +INET domain sockets. It establishes a TCP connection to a server, +then executes into a program. +</p> + +<h2> Interface </h2> + +<pre> + s6-tcpclient [ -q | -Q | -v ] [ -4 | -6 ] [ -d | -D ] [ -r | -R ] [ -h | -H ] [ -n | -N ] [ -t <em>timeout</em> ] [ -l <em>localname</em> ] [ -T <em>timeoutconn</em> ] [ -i <em>localip</em> ] [ -p <em>localport</em> ] <em>host</em> <em>port</em> <em>prog...</em> +</pre> + +<ul> + <li> s6-tcpclient establishes a TCP connection to host <em>host</em> +port <em>port</em>. </li> + <li> It executes into <em>prog...</em> with descriptor 6 reading from +the network and descriptor 7 writing to it. </li> +</ul> + +<h2> Host address determination </h2> + +<ul> + <li> <em>host</em> may be an IP address, in which case s6-tcpclient will +connect to that IP address. If the underlying skalibs has been +compiled with IPv6 support, <em>host</em> can be an IPv6 address as +well as an IPv4 one. </li> + <li> <em>host</em> may be a domain name, in which case a DNS +resolution will be performed on it, and a connection will be tried to +all the resulting IP addresses in a round-robin fashion, twice: +first with a small timeout, then with a longer timeout. The first +address to answer wins. The connection attempt fails if no address +in the list is able to answer. </li> +</ul> + +<h2> Environment variables </h2> + +<p> + <em>prog...</em> is run with the following variables set: +</p> + +<ul> + <li> PROTO: always set to TCP </li> + <li> TCPREMOTEIP: set to the chosen IP address of <em>host</em>. </li> + <li> TCPREMOTEPORT: set to <em>port</em>. </li> + <li> TCPREMOTEHOST: if the <tt>-H</tt> has been given, set to the +name obtained by a reverse DNS resolution of the IP address chosen +for <em>host</em>. Else unset. </li> + <li> TCPLOCALHOST: if the <tt>-l</tt> option has been given, set to +<em>localname</em>. Else set to the name obtained by a reverse DNS +resolution of the IP address chosen for the local host. </li> + <li> TCPREMOTEINFO: if the <tt>-r</tt> option has been given, set +to the information given by an IDENT server on <em>host</em> about +the current connection (very unreliable). Else unset. </li> +</ul> + +<h2> Options </h2> + +<ul> + <li> <tt>-q</tt> : be quiet. </li> + <li> <tt>-Q</tt> : be normally verbose. This is the default. </li> + <li> <tt>-v</tt> : be verbose. </li> + <li> <tt>-4</tt> : (only valid if the underlying skalibs has +IPv6 support) Interpret <em>host</em> as an IPv4 address or make A +queries to determine its addresses. </li> + <li> <tt>-6</tt> : (only valid if the underlying skalibs has +IPv6 support) Interpret <em>host</em> as an IPv6 address or make +AAAA queries to determine its addresses. This option and the previous +one are not mutually exclusive: if both are given, both IPv6 and +IPv4 addresses will be tried and IPv6 addresses will be given priority. +If neither option is given, only IPv4 address will be tried. </li> + <li> <tt>-d</tt> : don't use the TCP_NODELAY socket option. This +is the default. </li> + <li> <tt>-D</tt> : use the TCP_NODELAY socket option, which disables +Nagle's algorithm. </li> + <li> <tt>-r</tt> : try and obtain a TCPREMOTEINFO string via the +IDENT protocol. This is obsolete and unreliable, and should only be used for +compatibility with legacy programs. </li> + <li> <tt>-R</tt> : do not use the IDENT protocol. This is the +default. </li> + <li> <tt>-h</tt> : try and obtain the remote host name via DNS. +This is the default. </li> + <li> <tt>-H</tt> : do not try and obtain the remote host name +via DNS. </li> + <li> <tt>-n</tt> : qualify <em>host</em> when resolving it to +find suitable IP addresses. This is the default. </li> + <li> <tt>-N</tt> : do not qualify <em>host</em>. </li> + <li> <tt>-t :<em>timeout</em></tt> : put a global timeout +on the connection attempt. If no fully functional connection has been +established after <em>timeout</em> seconds, abort the program. By +default, <em>timeout</em> is 0, which means no timeout. </li> + <li> <tt>-i <em>localip</em></tt> : use <em>localip</em> as +the local socket address for the connection. By default, address selection +is left to the operating system. </li> + <li> <tt>-p <em>localport</em></tt> : use <em>localport</em> +as the local socket port for the connection. By default, port selection +is left to the operating system. </li> + <li> <tt>-l <em>localname</em></tt> : use <em>localname</em> +as the value of the TCPLOCALPATH environment variable instead of +looking it up via the DNS. </li> + <li> <tt>-T :<em>timeoutconn</em></tt> : configure the +connection timeouts. <em>timeoutconn</em> must be of the form +<em>x</em><tt>+</tt><em>y</em>, where <em>x</em> and <em>y</em> are +integers. <em>x</em> is the first timeout and <em>y</em> is the +second one: all suitable addresses for <em>host</em> are first +tried with a timeout of <em>x</em> seconds, and if all of them +fail, then they are tried again with a timeout of <em>y</em> +seconds. (Be aware that the timeout specified with the <tt>-t</tt> +option overrides everything.) By default, <em>x</em> is 2 and +<em>y</em> is 58. </li> +</ul> + +</body> +</html> |