diff options
Diffstat (limited to 'lib/kernel/doc/src/inet.xml')
| -rw-r--r-- | lib/kernel/doc/src/inet.xml | 1732 |
1 files changed, 887 insertions, 845 deletions
diff --git a/lib/kernel/doc/src/inet.xml b/lib/kernel/doc/src/inet.xml index 088d78c1d6..4c4a5c39cb 100644 --- a/lib/kernel/doc/src/inet.xml +++ b/lib/kernel/doc/src/inet.xml @@ -4,14 +4,14 @@ <erlref> <header> <copyright> - <year>1997</year><year>2015</year> + <year>1997</year><year>2016</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at - + http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software @@ -29,43 +29,47 @@ <rev>A</rev> </header> <module>inet</module> - <modulesummary>Access to TCP/IP Protocols</modulesummary> + <modulesummary>Access to TCP/IP protocols.</modulesummary> <description> - <p>Provides access to TCP/IP protocols.</p> - <p>See also <em>ERTS User's Guide, Inet configuration</em> for more - information on how to configure an Erlang runtime system for IP - communication.</p> - <p>Two Kernel configuration parameters affect the behaviour of all - sockets opened on an Erlang node: - <c>inet_default_connect_options</c> can contain a list of default - options used for all sockets returned when doing <c>connect</c>, - and <c>inet_default_listen_options</c> can contain a list of - default options used when issuing a <c>listen</c> call. When - <c>accept</c> is issued, the values of the listensocket options - are inherited, why no such application variable is needed for + <p>This module provides access to TCP/IP protocols.</p> + <p>See also + <seealso marker="erts:inet_cfg">ERTS User's Guide: + Inet Configuration</seealso> for more information about how to + configure an Erlang runtime system for IP communication.</p> + <p>The following two Kernel configuration parameters affect the + behavior of all sockets opened on an Erlang node:</p> + <list type="bulleted"> + <item><p><c>inet_default_connect_options</c> can contain a list of + default options used for all sockets returned when doing + <c>connect</c>.</p></item> + <item><p><c>inet_default_listen_options</c> can contain a list of + default options used when issuing a <c>listen</c> call.</p></item> + </list> + <p>When <c>accept</c> is issued, the values of the listening socket options + are inherited. No such application variable is therefore needed for <c>accept</c>.</p> - <p>Using the Kernel configuration parameters mentioned above, one - can set default options for all TCP sockets on a node. This should - be used with care, but options like <c>{delay_send,true}</c> - might be specified in this way. An example of starting an Erlang - node with all sockets using delayed send could look like this:</p> + <p>Using the Kernel configuration parameters above, one + can set default options for all TCP sockets on a node, but use this + with care. Options such as <c>{delay_send,true}</c> can be + specified in this way. The following is an example of starting an Erlang + node with all sockets using delayed send:</p> <pre> $ <input>erl -sname test -kernel \</input> <input>inet_default_connect_options '[{delay_send,true}]' \</input> <input>inet_default_listen_options '[{delay_send,true}]'</input></pre> - <p>Note that the default option <c>{active, true}</c> currently + <p>Notice that default option <c>{active, true}</c> cannot be changed, for internal reasons.</p> <p>Addresses as inputs to functions can be either a string or a - tuple. For instance, the IP address 150.236.20.73 can be passed to - <c>gethostbyaddr/1</c> either as the string "150.236.20.73" - or as the tuple <c>{150, 236, 20, 73}</c>.</p> - <p>IPv4 address examples:</p> + tuple. For example, the IP address 150.236.20.73 can be passed to + <c>gethostbyaddr/1</c>, either as string <c>"150.236.20.73"</c> + or as tuple <c>{150, 236, 20, 73}</c>.</p> + <p><em>IPv4 address examples:</em></p> <code type="none"> Address ip_address() ------- ------------ 127.0.0.1 {127,0,0,1} 192.168.42.2 {192,168,42,2}</code> - <p>IPv6 address examples:</p> + <p><em>IPv6 address examples:</em></p> <code type="none"> Address ip_address() ------- ------------ @@ -77,7 +81,9 @@ FFFF::192.168.42.2 {16#3ffe,16#b80,16#1f8d,16#2,16#204,16#acff,16#fe17,16#bf38} fe80::204:acff:fe17:bf38 {16#fe80,0,0,0,0,16#204,16#acff,16#fe17,16#bf38}</code> - <p>A function that may be useful is <seealso marker="#parse_address/1">parse_address/1</seealso>:</p> + <p>Function + <seealso marker="#parse_address/1"><c>parse_address/1</c></seealso> + can be useful:</p> <pre> 1> <input>inet:parse_address("192.168.42.2").</input> {ok,{192,168,42,2}} @@ -89,9 +95,12 @@ fe80::204:acff:fe17:bf38 <datatype> <name name="hostent"/> <desc> - <p>The record is defined in the Kernel include file "inet.hrl". - Add the following directive to the module:</p> -<code>-include_lib("kernel/include/inet.hrl").</code></desc> + <p>The record is defined in the Kernel include file + <c>"inet.hrl"</c>.</p> + <p>Add the following directive to the module:</p> + <code> +-include_lib("kernel/include/inet.hrl").</code> + </desc> </datatype> <datatype> <name name="hostname"/> @@ -109,18 +118,80 @@ fe80::204:acff:fe17:bf38 <name name="port_number"/> </datatype> <datatype> + <name name="local_address"/> + <desc> + <p> + This address family only works on Unix-like systems. + </p> + <p> + <c><anno>File</anno></c> is normally a file pathname + in a local filesystem. It is limited in length by the + operating system, traditionally to 108 bytes. + </p> + <p> + A <c>binary()</c> is passed as is to the operating system, + but a <c>string()</c> is encoded according to the + <seealso marker="file#native_name_encoding/0"> + system filename encoding mode. + </seealso> + </p> + <p> + Other addresses are possible, for example Linux implements + "Abstract Addresses". See the documentation for + Unix Domain Sockets on your system, + normally <c>unix</c> in manual section 7. + </p> + <p> + In most API functions where you can use + this address family the port number must be <c>0</c>. + </p> + </desc> + </datatype> + <datatype> + <name name="socket_address"/> + </datatype> + <datatype> + <name name="socket_getopt"/> + </datatype> + <datatype> + <name name="socket_setopt"/> + </datatype> + <datatype> + <name name="returned_non_ip_address"/> + <desc> + <p> + Addresses besides + <seealso marker="#type-ip_address"> + <c>ip_address()</c> + </seealso> + ones that are returned from socket API functions. + See in particular + <seealso marker="#type-local_address"> + <c>local_address()</c>. + </seealso> + The <c>unspec</c> family corresponds to AF_UNSPEC and can + occur if the other side has no socket address. + The <c>undefined</c> family can only occur in the unlikely + event of an address family that the VM does not recognize. + </p> + </desc> + </datatype> + <datatype> <name name="posix"/> - <desc><p>An atom which is named from the Posix error codes - used in Unix, and in the runtime libraries of most - C compilers. See + <desc> + <p>An atom that is named from the POSIX error codes used in Unix, + and in the runtime libraries of most C compilers. See section <seealso marker="#error_codes">POSIX Error Codes</seealso>.</p> </desc> </datatype> <datatype> <name>socket()</name> - <desc><p><marker id="type-socket"></marker> - See <seealso marker="gen_tcp#type-socket">gen_tcp(3)</seealso> - and <seealso marker="gen_udp#type-socket">gen_udp(3)</seealso>.</p> + <desc> + <p>See + <seealso marker="gen_tcp#type-socket"><c>gen_tcp:type-socket</c></seealso> + and + <seealso marker="gen_udp#type-socket"><c>gen_udp:type-socket</c></seealso>. + </p> </desc> </datatype> <datatype> @@ -131,443 +202,416 @@ fe80::204:acff:fe17:bf38 <funcs> <func> <name name="close" arity="1"/> - <fsummary>Close a socket of any type</fsummary> + <fsummary>Close a socket of any type.</fsummary> <desc> <p>Closes a socket of any type.</p> </desc> </func> + <func> - <name name="get_rc" arity="0"/> - <fsummary>Return a list of IP configuration parameters</fsummary> + <name name="format_error" arity="1"/> + <fsummary>Return a descriptive string for an error reason.</fsummary> <desc> - <p>Returns the state of the Inet configuration database in - form of a list of recorded configuration parameters. (See the - ERTS User's Guide, Inet configuration, for more information). - Only parameters with other than default values are returned.</p> + <p>Returns a diagnostic error string. For possible POSIX values and + corresponding strings, see section + <seealso marker="#error_codes">POSIX Error Codes</seealso>.</p> </desc> </func> + <func> - <name name="format_error" arity="1"/> - <fsummary>Return a descriptive string for an error reason</fsummary> + <name name="get_rc" arity="0"/> + <fsummary>Return a list of IP configuration parameters.</fsummary> <desc> - <p>Returns a diagnostic error string. See the section below - for possible Posix values and the corresponding - strings.</p> + <p>Returns the state of the <c>Inet</c> configuration database in + form of a list of recorded configuration parameters. For more + information, see <seealso marker="erts:inet_cfg">ERTS User's Guide: + Inet Configuration</seealso>. + Only parameters with other than default values are returned.</p> </desc> </func> + <func> <name name="getaddr" arity="2"/> - <fsummary>Return the IP-address for a host</fsummary> + <fsummary>Return the IP address for a host.</fsummary> <desc> - <p>Returns the IP-address for <c><anno>Host</anno></c> as a tuple of - integers. <c><anno>Host</anno></c> can be an IP-address, a single hostname - or a fully qualified hostname.</p> + <p>Returns the IP address for <c><anno>Host</anno></c> as a tuple of + integers. <c><anno>Host</anno></c> can be an IP address, a single + hostname, or a fully qualified hostname.</p> </desc> </func> + <func> <name name="getaddrs" arity="2"/> - <fsummary>Return the IP-addresses for a host</fsummary> + <fsummary>Return the IP addresses for a host.</fsummary> <desc> - <p>Returns a list of all IP-addresses for <c><anno>Host</anno></c>. - <c><anno>Host</anno></c> can be an IP-address, a single hostname or a fully - qualified hostname.</p> + <p>Returns a list of all IP addresses for <c><anno>Host</anno></c>. + <c><anno>Host</anno></c> can be an IP address, a single hostname, or + a fully qualified hostname.</p> </desc> </func> + <func> <name name="gethostbyaddr" arity="1"/> - <fsummary>Return a hostent record for the host with the given address</fsummary> + <fsummary>Return a hostent record for the host with the specified + address.</fsummary> <desc> - <p>Returns a <c>hostent</c> record given an address.</p> - </desc> + <p>Returns a <c>hostent</c> record for the host with the specified + address.</p></desc> </func> + <func> <name name="gethostbyname" arity="1"/> - <fsummary>Return a hostent record for the host with the given name</fsummary> + <fsummary>Return a hostent record for the host with the specified name. + </fsummary> <desc> - <p>Returns a <c>hostent</c> record given a hostname.</p> + <p>Returns a <c>hostent</c> record for the host with the specified + hostname.</p> + <p>If resolver option <c>inet6</c> is <c>true</c>, + an IPv6 address is looked up. If that fails, + the IPv4 address is looked up and returned on + IPv6-mapped IPv4 format.</p> </desc> </func> + <func> <name name="gethostbyname" arity="2"/> - <fsummary>Return a hostent record for the host with the given name</fsummary> + <fsummary>Return a hostent record for the host with the specified name. + </fsummary> <desc> - <p>Returns a <c>hostent</c> record given a hostname, restricted - to the given address family.</p> + <p>Returns a <c>hostent</c> record for the host with the specified + name, restricted to the specified address family.</p> </desc> </func> + <func> <name name="gethostname" arity="0"/> - <fsummary>Return the local hostname</fsummary> + <fsummary>Return the local hostname.</fsummary> <desc> - <p>Returns the local hostname. Will never fail.</p> + <p>Returns the local hostname. Never fails.</p> </desc> </func> <func> <name name="getifaddrs" arity="0"/> - <fsummary>Return a list of interfaces and their addresses</fsummary> - <desc> - <p> - Returns a list of 2-tuples containing interface names and the - interface's addresses. <c><anno>Ifname</anno></c> is a Unicode string. - <c><anno>Hwaddr</anno></c> is hardware dependent, e.g on Ethernet interfaces - it is the 6-byte Ethernet address (MAC address (EUI-48 address)). - </p> - <p> - The <c>{addr,<anno>Addr</anno>}</c>, <c>{netmask,_}</c> and <c>{broadaddr,_}</c> - tuples are repeated in the result list iff the interface has multiple - addresses. If you come across an interface that has - multiple <c>{flag,_}</c> or <c>{hwaddr,_}</c> tuples you have - a really strange interface or possibly a bug in this function. - The <c>{flag,_}</c> tuple is mandatory, all other optional. - </p> - <p> - Do not rely too much on the order of <c><anno>Flag</anno></c> atoms or - <c><anno>Ifopt</anno></c> tuples. There are some rules, though:</p> - <list> - <item> - Immediately after <c>{addr,_}</c> follows <c>{netmask,_}</c> - </item> - <item> - Immediately thereafter follows <c>{broadaddr,_}</c> if - the <c>broadcast</c> flag is <em>not</em> set and the - <c>pointtopoint</c> flag <em>is</em> set. - </item> - <item> - Any <c>{netmask,_}</c>, <c>{broadaddr,_}</c> or - <c>{dstaddr,_}</c> tuples that follow an <c>{addr,_}</c> - tuple concerns that address. - </item> - </list> - <p> - The <c>{hwaddr,_}</c> tuple is not returned on Solaris since the - hardware address historically belongs to the link layer and only - the superuser can read such addresses. - </p> - <p> - On Windows, the data is fetched from quite different OS API - functions, so the <c><anno>Netmask</anno></c> and <c><anno>Broadaddr</anno></c> - values may be calculated, just as some <c><anno>Flag</anno></c> values. - You have been warned. Report flagrant bugs. - </p> - </desc> + <fsummary>Return a list of interfaces and their addresses.</fsummary> + <desc> + <p>Returns a list of 2-tuples containing interface names and the + interface addresses. <c><anno>Ifname</anno></c> is a Unicode string. + <c><anno>Hwaddr</anno></c> is hardware dependent, for example, on + Ethernet interfaces + it is the 6-byte Ethernet address (MAC address (EUI-48 address)).</p> + <p>The tuples <c>{addr,<anno>Addr</anno>}</c>, <c>{netmask,_}</c>, and + <c>{broadaddr,_}</c> are repeated in the result list if the interface + has multiple addresses. If you come across an interface with + multiple <c>{flag,_}</c> or <c>{hwaddr,_}</c> tuples, you have + a strange interface or possibly a bug in this function. The tuple + <c>{flag,_}</c> is mandatory, all others are optional.</p> + <p>Do not rely too much on the order of <c><anno>Flag</anno></c> atoms + or <c><anno>Ifopt</anno></c> tuples. There are however some rules:</p> + <list type="bulleted"> + <item><p>Immediately after + <c>{addr,_}</c> follows <c>{netmask,_}</c>.</p></item> + <item><p>Immediately thereafter follows <c>{broadaddr,_}</c> if flag + <c>broadcast</c> is <em>not</em> set and flag + <c>pointtopoint</c> <em>is</em> set.</p></item> + <item><p>Any <c>{netmask,_}</c>, <c>{broadaddr,_}</c>, or + <c>{dstaddr,_}</c> tuples that follow an <c>{addr,_}</c> + tuple concerns that address.</p></item> + </list> + <p>The tuple <c>{hwaddr,_}</c> is not returned on Solaris, as the + hardware address historically belongs to the link layer and only + the superuser can read such addresses.</p> + <warning> + <p>On Windows, the data is fetched from different OS API functions, + so the <c><anno>Netmask</anno></c> and <c><anno>Broadaddr</anno></c> + values can be calculated, just as some <c><anno>Flag</anno></c> + values. Report flagrant bugs.</p> + </warning> + </desc> </func> <func> <name name="getopts" arity="2"/> - <fsummary>Get one or more options for a socket</fsummary> - <type name="socket_getopt"/> - <type name="socket_setopt"/> + <fsummary>Get one or more options for a socket.</fsummary> <desc> - <p>Gets one or more options for a socket. - See <seealso marker="#setopts/2">setopts/2</seealso> - for a list of available options.</p> - <p>The number of elements in the returned <c><anno>OptionValues</anno></c> + <p>Gets one or more options for a socket. For a list of available + options, see + <seealso marker="#setopts/2"><c>setopts/2</c></seealso>.</p> + <p>The number of elements in the returned + <c><anno>OptionValues</anno></c> list does not necessarily correspond to the number of options asked for. If the operating system fails to support an option, - it is simply left out in the returned list. An error tuple is only - returned when getting options for the socket is impossible - (i.e. the socket is closed or the buffer size in a raw request + it is left out in the returned list. An error tuple is returned + only when getting options for the socket is impossible (that is, + the socket is closed or the buffer size in a raw request is too large). This behavior is kept for backward compatibility reasons.</p> - <p>A raw option request <c>RawOptReq = {raw, Protocol, OptionNum, ValueSpec}</c> can be used to get information about + <p>A raw option request + <c>RawOptReq = {raw, Protocol, OptionNum, ValueSpec}</c> + can be used to get information about socket options not (explicitly) supported by the emulator. The - use of raw socket options makes the code non portable, but + use of raw socket options makes the code non-portable, but allows the Erlang programmer to take advantage of unusual features present on the current platform.</p> - <p>The <c>RawOptReq</c> consists of the tag <c>raw</c> followed - by the protocol level, the option number and either a binary + <p><c>RawOptReq</c> consists of tag <c>raw</c> followed + by the protocol level, the option number, and either a binary or the size, in bytes, of the - buffer in which the option value is to be stored. A binary - should be used when the underlying <c>getsockopt</c> requires - <em>input</em> - in the argument field, in which case the size of the binary - should correspond to the required buffer + buffer in which the option value is to be stored. A binary is to be + used when the underlying <c>getsockopt</c> requires <em>input</em> + in the argument field. In this case, the binary size + is to correspond to the required buffer size of the return value. The supplied values in a <c>RawOptReq</c> - correspond to the second, third and fourth/fifth parameters to the + correspond to the second, third, and fourth/fifth parameters to the <c>getsockopt</c> call in the C socket API. The value stored - in the buffer is returned as a binary <c>ValueBin</c> + in the buffer is returned as a binary <c>ValueBin</c>, where all values are coded in the native endianess.</p> - <p>Asking for and inspecting raw socket options require low - level information about the current operating system and TCP - stack.</p> - <p>As an example, consider a Linux machine where the - <c>TCP_INFO</c> option could be used to collect TCP statistics - for a socket. Lets say we're interested in the - <c>tcpi_sacked</c> field of the <c>struct tcp_info</c> - filled in when asking for <c>TCP_INFO</c>. To - be able to access this information, we need to know both the - numeric value of the protocol level <c>IPPROTO_TCP</c>, the - numeric value of the option <c>TCP_INFO</c>, the size of the - <c>struct tcp_info</c> and the size and offset of - the specific field. By inspecting the headers or writing a small C - program, we found <c>IPPROTO_TCP</c> to be 6, - <c>TCP_INFO</c> to be 11, the structure size to be 92 (bytes), - the offset of <c>tcpi_sacked</c> to be 28 bytes and the actual - value to be a 32 bit integer. We could use the following - code to retrieve the value:</p> + <p>Asking for and inspecting raw socket options require low-level + information about the current operating system and TCP stack.</p> + <p><em>Example:</em></p> + <p>Consider a Linux machine where option + <c>TCP_INFO</c> can be used to collect TCP statistics + for a socket. Assume you are interested in field + <c>tcpi_sacked</c> of <c>struct tcp_info</c> + filled in when asking for <c>TCP_INFO</c>. To be able to access + this information, you need to know the following:</p> + <list type="bulleted"> + <item>The numeric value of protocol level <c>IPPROTO_TCP</c></item> + <item>The numeric value of option <c>TCP_INFO</c></item> + <item>The size of <c>struct tcp_info</c></item> + <item>The size and offset of the specific field</item> + </list> + <p>By inspecting the headers or writing a small C program, it is found + that <c>IPPROTO_TCP</c> is 6, <c>TCP_INFO</c> is 11, the structure + size is 92 (bytes), the offset of <c>tcpi_sacked</c> is 28 bytes, + and the value is a 32-bit integer. The following code can be used + to retrieve the value:</p> <code type="none"><![CDATA[ - get_tcpi_sacked(Sock) -> - {ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]), - <<_:28/binary,TcpiSacked:32/native,_/binary>> = Info, - TcpiSacked.]]></code> - <p>Preferably, you would check the machine type, the OS - and the kernel version prior to executing anything similar to the - code above.</p> +get_tcpi_sacked(Sock) -> + {ok,[{raw,_,_,Info}]} = inet:getopts(Sock,[{raw,6,11,92}]), + <<_:28/binary,TcpiSacked:32/native,_/binary>> = Info, + TcpiSacked.]]></code> + <p>Preferably, you would check the machine type, the operating system, + and the Kernel version before executing anything similar to + this code.</p> </desc> </func> <func> <name name="getstat" arity="1"/> <name name="getstat" arity="2"/> - <fsummary>Get one or more statistic options for a socket</fsummary> + <fsummary>Get one or more statistic options for a socket.</fsummary> <type name="stat_option"/> <desc> <p>Gets one or more statistic options for a socket.</p> - - <p><c>getstat(<anno>Socket</anno>)</c> is equivalent to - <c>getstat(<anno>Socket</anno>, [recv_avg, recv_cnt, recv_dvi, - recv_max, recv_oct, send_avg, send_cnt, send_dvi, send_max, - send_oct])</c>.</p> - <p>The following options are available:</p> + <p><c>getstat(<anno>Socket</anno>)</c> is equivalent to + <c>getstat(<anno>Socket</anno>, [recv_avg, recv_cnt, recv_dvi, + recv_max, recv_oct, send_avg, send_cnt, send_dvi, send_max, + send_oct])</c>.</p> + <p>The following options are available:</p> <taglist> - <tag><c>recv_avg</c></tag> - <item> - <p>Average size of packets in bytes received by the socket.</p> - </item> - <tag><c>recv_cnt</c></tag> - <item> + <tag><c>recv_avg</c></tag> + <item> + <p>Average size of packets, in bytes, received by the socket.</p> + </item> + <tag><c>recv_cnt</c></tag> + <item> <p>Number of packets received by the socket.</p> - </item> - <tag><c>recv_dvi</c></tag> - <item> - <p>Average packet size deviation in bytes received by the socket.</p> - </item> - <tag><c>recv_max</c></tag> - <item> - <p>The size of the largest packet in bytes received by the socket.</p> - </item> - <tag><c>recv_oct</c></tag> - <item> + </item> + <tag><c>recv_dvi</c></tag> + <item> + <p>Average packet size deviation, in bytes, received by the socket.</p> + </item> + <tag><c>recv_max</c></tag> + <item> + <p>Size of the largest packet, in bytes, received by the socket.</p> + </item> + <tag><c>recv_oct</c></tag> + <item> <p>Number of bytes received by the socket.</p> - </item> - - <tag><c>send_avg</c></tag> - <item> - <p>Average size of packets in bytes sent from the socket.</p> - </item> - <tag><c>send_cnt</c></tag> - <item> + </item> + <tag><c>send_avg</c></tag> + <item> + <p>Average size of packets, in bytes, sent from the socket.</p> + </item> + <tag><c>send_cnt</c></tag> + <item> <p>Number of packets sent from the socket.</p> - </item> - <tag><c>send_dvi</c></tag> - <item> - <p>Average packet size deviation in bytes sent from the socket.</p> - </item> - <tag><c>send_max</c></tag> - <item> - <p>The size of the largest packet in bytes sent from the socket.</p> - </item> - <tag><c>send_oct</c></tag> - <item> + </item> + <tag><c>send_dvi</c></tag> + <item> + <p>Average packet size deviation, in bytes, sent from the socket.</p> + </item> + <tag><c>send_max</c></tag> + <item> + <p>Size of the largest packet, in bytes, sent from the socket.</p> + </item> + <tag><c>send_oct</c></tag> + <item> <p>Number of bytes sent from the socket.</p> - </item> + </item> </taglist> </desc> </func> + <func> <name name="ntoa" arity="1" /> - <fsummary>Convert IPv6 / IPV4 adress to ascii</fsummary> + <fsummary>Convert IPv6/IPV4 address to ASCII.</fsummary> <desc> - <p>Parses an <seealso marker="#type-ip_address">ip_address()</seealso> and returns an IPv4 or IPv6 address string.</p> + <p>Parses an + <seealso marker="#type-ip_address"><c>ip_address()</c></seealso> + and returns an IPv4 or IPv6 address string.</p> </desc> </func> + + <func> + <name name="parse_address" arity="1" /> + <fsummary>Parse an IPv4 or IPv6 address.</fsummary> + <desc> + <p>Parses an IPv4 or IPv6 address string and returns an + <seealso marker="#type-ip4_address"><c>ip4_address()</c></seealso> or + <seealso marker="#type-ip6_address"><c>ip6_address()</c></seealso>. + Accepts a shortened IPv4 address string.</p> + </desc> + </func> + <func> <name name="parse_ipv4_address" arity="1" /> - <fsummary>Parse an IPv4 address</fsummary> + <fsummary>Parse an IPv4 address.</fsummary> <desc> - <p>Parses an IPv4 address string and returns an <seealso marker="#type-ip4_address">ip4_address()</seealso>. - Accepts a shortened IPv4 shortened address string.</p> + <p>Parses an IPv4 address string and returns an + <seealso marker="#type-ip4_address"><c>ip4_address()</c></seealso>. + Accepts a shortened IPv4 address string.</p> </desc> </func> + <func> <name name="parse_ipv4strict_address" arity="1" /> <fsummary>Parse an IPv4 address strict.</fsummary> <desc> - <p>Parses an IPv4 address string containing four fields, i.e <em>not</em> shortened, and returns an <seealso marker="#type-ip4_address">ip4_address()</seealso>.</p> + <p>Parses an IPv4 address string containing four fields, that is, + <em>not</em> shortened, and returns an + <seealso marker="#type-ip4_address"><c>ip4_address()</c></seealso>. + </p> </desc> </func> + <func> <name name="parse_ipv6_address" arity="1" /> - <fsummary>Parse an IPv6 address</fsummary> + <fsummary>Parse an IPv6 address.</fsummary> <desc> - <p>Parses an IPv6 address string and returns an <seealso marker="#type-ip6_address">ip6_address()</seealso>. - If an IPv4 address string is passed, an IPv4-mapped IPv6 address is returned.</p> + <p>Parses an IPv6 address string and returns an + <seealso marker="#type-ip6_address"><c>ip6_address()</c></seealso>. + If an IPv4 address string is specified, an IPv4-mapped IPv6 address + is returned.</p> </desc> </func> + <func> <name name="parse_ipv6strict_address" arity="1" /> <fsummary>Parse an IPv6 address strict.</fsummary> <desc> - <p>Parses an IPv6 address string and returns an <seealso marker="#type-ip6_address">ip6_address()</seealso>. - Does <em>not</em> accept IPv4 adresses.</p> - </desc> - </func> - <func> - <name name="parse_address" arity="1" /> - <fsummary>Parse an IPv4 or IPv6 address.</fsummary> - <desc> - <p>Parses an IPv4 or IPv6 address string and returns an <seealso marker="#type-ip4_address">ip4_address()</seealso> or <seealso marker="#type-ip6_address">ip6_address()</seealso>. Accepts a shortened IPv4 address string.</p> + <p>Parses an IPv6 address string and returns an + <seealso marker="#type-ip6_address"><c>ip6_address()</c></seealso>. + Does <em>not</em> accept IPv4 addresses.</p> </desc> </func> + <func> <name name="parse_strict_address" arity="1" /> <fsummary>Parse an IPv4 or IPv6 address strict.</fsummary> <desc> - <p>Parses an IPv4 or IPv6 address string and returns an <seealso marker="#type-ip4_address">ip4_address()</seealso> or <seealso marker="#type-ip6_address">ip6_address()</seealso>. Does <em>not</em> accept a shortened IPv4 address string.</p> + <p>Parses an IPv4 or IPv6 address string and returns an + <seealso marker="#type-ip4_address"><c>ip4_address()</c></seealso> or + <seealso marker="#type-ip6_address"><c>ip6_address()</c></seealso>. + Does <em>not</em> accept a shortened IPv4 address string.</p> </desc> </func> + <func> <name name="peername" arity="1"/> - <fsummary>Return the address and port for the other end of a connection</fsummary> + <fsummary>Return the address and port for the other end of a connection. + </fsummary> <desc> - <p> - Returns the address and port for the other end of a - connection. - </p> - <p> - Note that for SCTP sockets this function only returns - one of the socket's peer addresses. The function - <seealso marker="#peernames/1">peernames/1,2</seealso> - returns all. - </p> + <p>Returns the address and port for the other end of a connection.</p> + <p>Notice that for SCTP sockets, this function returns only + one of the peer addresses of the socket. Function + <seealso marker="#peernames/1"><c>peernames/1,2</c></seealso> + returns all.</p> </desc> </func> + <func> <name name="peernames" arity="1"/> - <fsummary> - Return all address/port numbers for the other end of a connection - </fsummary> + <fsummary>Return all address/port numbers for the other end of a + connection.</fsummary> <desc> - <p> - Equivalent to + <p>Equivalent to <seealso marker="#peernames/2"><c>peernames(<anno>Socket</anno>, 0)</c></seealso>. - Note that this function's behaviour for an SCTP + </p> + <p>Notice that the behavior of this function for an SCTP one-to-many style socket is not defined by the - <url href="http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13">SCTP Sockets API Extensions</url>. - </p> + <url href="http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13">SCTP Sockets API Extensions</url>.</p> </desc> </func> + <func> <name name="peernames" arity="2"/> - <fsummary> - Return all address/port numbers for the other end of a connection - </fsummary> + <fsummary>Return all address/port numbers for the other end of a + connection.</fsummary> <desc> - <p> - Returns a list of all address/port number pairs for the other end - of a socket's association <c><anno>Assoc</anno></c>. - </p> - <p> - This function can return multiple addresses for multihomed - sockets such as SCTP sockets. For other sockets it - returns a one element list. - </p> - <p> - Note that the <c><anno>Assoc</anno></c> parameter is by the + <p>Returns a list of all address/port number pairs for the other end + of an association <c><anno>Assoc</anno></c> of a socket.</p> + <p>This function can return multiple addresses for multihomed + sockets, such as SCTP sockets. For other sockets it + returns a one-element list.</p> + <p>Notice that parameter <c><anno>Assoc</anno></c> is by the <url href="http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13">SCTP Sockets API Extensions</url> defined to be ignored for - one-to-one style sockets. What the special value <c>0</c> - means hence its behaviour for one-to-many style sockets - is unfortunately not defined. - </p> + one-to-one style sockets. What the special value <c>0</c> + means, hence its behavior for one-to-many style sockets, + is unfortunately undefined.</p> </desc> </func> + <func> <name name="port" arity="1"/> - <fsummary>Return the local port number for a socket</fsummary> + <fsummary>Return the local port number for a socket.</fsummary> <desc> <p>Returns the local port number for a socket.</p> </desc> </func> - <func> - <name name="sockname" arity="1"/> - <fsummary>Return the local address and port number for a socket</fsummary> - <desc> - <p>Returns the local address and port number for a socket.</p> - <p> - Note that for SCTP sockets this function only returns - one of the socket addresses. The function - <seealso marker="#socknames/1">socknames/1,2</seealso> - returns all. - </p> - </desc> - </func> - <func> - <name name="socknames" arity="1"/> - <fsummary>Return all local address/port numbers for a socket</fsummary> - <desc> - <p> - Equivalent to - <seealso marker="#socknames/2"><c>socknames(<anno>Socket</anno>, 0)</c></seealso>. - </p> - </desc> - </func> - <func> - <name name="socknames" arity="2"/> - <fsummary>Return all local address/port numbers for a socket</fsummary> - <desc> - <p> - Returns a list of all local address/port number pairs for a socket - for the given association <c><anno>Assoc</anno></c>. - </p> - <p> - This function can return multiple addresses for multihomed - sockets such as SCTP sockets. For other sockets it - returns a one element list. - </p> - <p> - Note that the <c><anno>Assoc</anno></c> parameter is by the - <url href="http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13">SCTP Sockets API Extensions</url> - defined to be ignored for one-to-one style sockets. - For one-to-many style sockets the special value <c>0</c> - is defined to mean that the returned addresses shall be - without regard to any particular association. - How different SCTP implementations interprets this varies somewhat. - </p> - </desc> - </func> + <func> <name name="setopts" arity="2"/> - <fsummary>Set one or more options for a socket</fsummary> - <type name="socket_setopt"/> + <fsummary>Set one or more options for a socket.</fsummary> <desc> - <p>Sets one or more options for a socket. The following options - are available:</p> + <p>Sets one or more options for a socket.</p> + <p>The following options are available:</p> <taglist> <tag><c>{active, true | false | once | N}</c></tag> <item> <p>If the value is <c>true</c>, which is the default, - everything received from the socket will be sent as - messages to the receiving process. If the value is - <c>false</c> (passive mode), the process must explicitly - receive incoming data by calling + everything received from the socket is sent as + messages to the receiving process.</p> + <p>If the value is <c>false</c> (passive mode), the process must + explicitly receive incoming data by calling <seealso marker="gen_tcp#recv/2"><c>gen_tcp:recv/2,3</c></seealso>, - <seealso marker="gen_udp#recv/2"><c>gen_udp:recv/2,3</c></seealso> + <seealso marker="gen_udp#recv/2"><c>gen_udp:recv/2,3</c></seealso>, or <seealso marker="gen_sctp#recv/1"><c>gen_sctp:recv/1,2</c></seealso> (depending on the type of socket).</p> <p>If the value is <c>once</c> (<c>{active, once}</c>), - <em>one</em> data message from the socket will be sent - to the process. To receive one more message, - <c>setopts/2</c> must be called again with the - <c>{active, once}</c> option.</p> + <em>one</em> data message from the socket is sent + to the process. To receive one more message, + <c>setopts/2</c> must be called again with option + <c>{active, once}</c>.</p> <p>If the value is an integer <c>N</c> in the range -32768 to 32767 (inclusive), the value is added to the socket's count of data messages sent to the controlling process. A socket's default - message count is 0. If a negative value is specified and its - magnitude is equal to or greater than the socket's current - message count, the socket's message count is set to 0. Once - the socket's message count reaches 0, either due to sending + message count is <c>0</c>. If a negative value is specified, and + its magnitude is equal to or greater than the socket's current + message count, the socket's message count is set to <c>0</c>. + Once the socket's message count reaches <c>0</c>, either because + of sending received data messages to the process or by being explicitly set, the process is then notified by a special message, specific to the type of socket, that the socket has entered passive @@ -575,339 +619,298 @@ fe80::204:acff:fe17:bf38 messages <c>setopts/2</c> must be called again to set the socket back into an active mode.</p> <p>When using <c>{active, once}</c> or <c>{active, N}</c>, the - socket changes behaviour automatically when data is received. - This can sometimes be confusing in combination with - connection-oriented sockets (i.e. <c>gen_tcp</c>) as a socket - with <c>{active, false}</c> behaviour reports closing + socket changes behavior automatically when data is received. + This can be confusing in combination with connection-oriented + sockets (that is, <c>gen_tcp</c>), as a socket + with <c>{active, false}</c> behavior reports closing differently than a socket with <c>{active, true}</c> - behaviour. To make programming easier, a socket where - the peer closed and this was detected while in - <c>{active, false}</c> mode, will still generate the - message + behavior. To simplify programming, a socket where + the peer closed, and this is detected while in + <c>{active, false}</c> mode, still generates message <c>{tcp_closed,Socket}</c> when set to <c>{active, once}</c>, - <c>{active, true}</c> or <c>{active, N}</c> mode. It is therefore - safe to assume that the message - <c>{tcp_closed,Socket}</c>, possibly followed by socket - port termination (depending on the <c>exit_on_close</c> - option) will eventually appear when a socket changes + <c>{active, true}</c>, or <c>{active, N}</c> mode. + It is therefore safe to assume that message + <c>{tcp_closed,Socket}</c>, possibly followed by socket port + termination (depending on option <c>exit_on_close</c>) + eventually appears when a socket changes back and forth between <c>{active, true}</c> and <c>{active, false}</c> mode. However, - <em>when</em> peer closing is detected is all up to the + <em>when</em> peer closing is detected it is all up to the underlying TCP/IP stack and protocol.</p> - <p>Note that <c>{active, true}</c> mode provides no flow - control; a fast sender could easily overflow the - receiver with incoming messages. The same is true of - <c>{active, N}</c> mode while the message count is greater - than zero. Use active mode only if + <p>Notice that <c>{active, true}</c> mode provides no flow + control; a fast sender can easily overflow the + receiver with incoming messages. The same is true for + <c>{active, N}</c> mode, while the message count is greater + than zero.</p> + <p>Use active mode only if your high-level protocol provides its own flow control - (for instance, acknowledging received messages) or the + (for example, acknowledging received messages) or the amount of data exchanged is small. <c>{active, false}</c> - mode, use of the <c>{active, once}</c> mode or <c>{active, N}</c> + mode, use of the <c>{active, once}</c> mode, or <c>{active, N}</c> mode with values of <c>N</c> appropriate for the application - provides flow control; the other side will not be able send + provides flow control. The other side cannot send faster than the receiver can read.</p> </item> - - <tag><c>{broadcast, Boolean}</c>(UDP sockets)</tag> + <tag><c>{broadcast, Boolean}</c> (UDP sockets)</tag> <item> - <p>Enable/disable permission to send broadcasts.</p> - <marker id="option-buffer"></marker> + <p>Enables/disables permission to send broadcasts.</p> + <marker id="option-buffer"></marker> + </item> + <tag><c>{buffer, Size}</c></tag> + <item> + <p>The size of the user-level software buffer used by + the driver. Not to be confused with options <c>sndbuf</c> + and <c>recbuf</c>, which correspond to the + Kernel socket buffers. It is recommended + to have <c>val(buffer) >= max(val(sndbuf),val(recbuf))</c> to + avoid performance issues because of unnecessary copying. + <c>val(buffer)</c> is automatically set to the above + maximum when values <c>sndbuf</c> or <c>recbuf</c> are set. + However, as the sizes set for <c>sndbuf</c> and <c>recbuf</c> + usually become larger, you are encouraged to use + <seealso marker="#getopts/2"><c>getopts/2</c></seealso> + to analyze the behavior of your operating system.</p> </item> - - <tag><c>{buffer, Size}</c></tag> - <item> - <p>The size of the user-level software buffer used by - the driver. Not to be confused with <c>sndbuf</c> - and <c>recbuf</c> options which correspond to - the kernel socket buffers. It is recommended - to have <c>val(buffer) >= max(val(sndbuf),val(recbuf))</c> to - avoid performance issues due to unnecessary copying. - In fact, the <c>val(buffer)</c> is automatically set to - the above maximum when <c>sndbuf</c> or <c>recbuf</c> values are set. - However, since the actual sizes set for <c>sndbuf</c> and <c>recbuf</c> - usually becomes larger, you are encouraged to use - <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso> - to analyze the behavior of your operating system.</p> - </item> - <tag><c>{delay_send, Boolean}</c></tag> <item> <p>Normally, when an Erlang process sends to a socket, - the driver will try to immediately send the data. If that - fails, the driver will use any means available to queue + the driver tries to send the data immediately. If that + fails, the driver uses any means available to queue up the message to be sent whenever the operating system says it can handle it. Setting <c>{delay_send, true}</c> - will make <em>all</em> messages queue up. This makes - the messages actually sent onto the network be larger but - fewer. The option actually affects the scheduling of send + makes <em>all</em> messages queue up. The messages sent + to the network are then larger but fewer. + The option affects the scheduling of send requests versus Erlang processes instead of changing any - real property of the socket. Needless to say it is an - implementation specific option. Default is <c>false</c>.</p> + real property of the socket. The option is + implementation-specific. Defaults to <c>false</c>.</p> + </item> + <tag><c>{deliver, port | term}</c></tag> + <item> + <p>When <c>{active, true}</c>, data is delivered on the form + <c>port</c> : <c>{S, {data, [H1,..Hsz | Data]}}</c> or + <c>term</c> : <c>{tcp, S, [H1..Hsz | Data]}</c>.</p> </item> - - <tag><c>{deliver, port | term}</c></tag> - <item> <p> When <c>{active, true}</c> delivers data on the forms - <c>port</c> : <c>{S, {data, [H1,..Hsz | Data]}}</c> or - <c>term</c> : <c>{tcp, S, [H1..Hsz | Data]}</c>. - </p> - </item> - <tag><c>{dontroute, Boolean}</c></tag> <item> - <p>Enable/disable routing bypass for outgoing messages.</p> + <p>Enables/disables routing bypass for outgoing messages.</p> </item> - <tag><c>{exit_on_close, Boolean}</c></tag> <item> - <p>By default this option is set to <c>true</c>.</p> + <p>This option is set to <c>true</c> by default.</p> <p>The only reason to set it to <c>false</c> is if you want - to continue sending data to the socket after a close has - been detected, for instance if the peer has used - <seealso marker="gen_tcp#shutdown/2">gen_tcp:shutdown/2</seealso> - to shutdown the write side.</p> + to continue sending data to the socket after a close is + detected, for example, if the peer uses + <seealso marker="gen_tcp#shutdown/2"><c>gen_tcp:shutdown/2</c></seealso> + to shut down the write side.</p> </item> - <tag><c>{header, Size}</c></tag> <item> - <p>This option is only meaningful if the <c>binary</c> - option was specified when the socket was created. If - the <c>header</c> option is specified, the first + <p>This option is only meaningful if option <c>binary</c> + was specified when the socket was created. If option + <c>header</c> is specified, the first <c>Size</c> number bytes of data received from the socket - will be elements of a list, and the rest of the data will - be a binary given as the tail of the same list. If for - example <c>Size == 2</c>, the data received will match + are elements of a list, and the remaining data is + a binary specified as the tail of the same list. For example, + if <c>Size == 2</c>, the data received matches <c>[Byte1,Byte2|Binary]</c>.</p> </item> - <tag><c>{high_msgq_watermark, Size}</c></tag> <item> - <p>The socket message queue will be set into a busy - state when the amount of data queued on the message - queue reaches this limit. Note that this limit only - concerns data that have not yet reached the ERTS internal - socket implementation. Default value used is 8 kB.</p> - <p>Senders of data to the socket will be suspended if - either the socket message queue is busy, or the socket - itself is busy.</p> - <p>For more information see the <c>low_msgq_watermark</c>, - <c>high_watermark</c>, and <c>low_watermark</c> options.</p> - <p>Note that distribution sockets will disable the use of - <c>high_msgq_watermark</c> and <c>low_msgq_watermark</c>, - and will instead use the - <seealso marker="erts:erlang#system_info_dist_buf_busy_limit">distribution - buffer busy limit</seealso> which is a similar feature.</p> + <p>The socket message queue is set to a busy + state when the amount of data on the message + queue reaches this limit. Notice that this limit only + concerns data that has not yet reached the ERTS internal + socket implementation. Defaults to 8 kB.</p> + <p>Senders of data to the socket are suspended if + either the socket message queue is busy or the socket + itself is busy.</p> + <p>For more information, see options <c>low_msgq_watermark</c>, + <c>high_watermark</c>, and <c>low_watermark</c>.</p> + <p>Notice that distribution sockets disable the use of + <c>high_msgq_watermark</c> and <c>low_msgq_watermark</c>. + Instead use the + <seealso marker="erts:erlang#system_info_dist_buf_busy_limit">distribution buffer busy limit</seealso>, + which is a similar feature.</p> </item> - <tag><c>{high_watermark, Size}</c> (TCP/IP sockets)</tag> <item> - <p>The socket will be set into a busy state when the amount - of data queued internally by the ERTS socket implementation - reaches this limit. Default value used is 8 kB.</p> - <p>Senders of data to the socket will be suspended if - either the socket message queue is busy, or the socket - itself is busy.</p> - <p>For more information see the <c>low_watermark</c>, - <c>high_msgq_watermark</c>, and <c>low_msqg_watermark</c> - options.</p> + <p>The socket is set to a busy state when the amount + of data queued internally by the ERTS socket implementation + reaches this limit. Defaults to 8 kB.</p> + <p>Senders of data to the socket are suspended if + either the socket message queue is busy or the socket + itself is busy.</p> + <p>For more information, see options <c>low_watermark</c>, + <c>high_msgq_watermark</c>, and <c>low_msqg_watermark</c>.</p> </item> - <tag><c>{ipv6_v6only, Boolean}</c></tag> <item> - <p> - Restricts the socket to only use IPv6, prohibiting any + <p>Restricts the socket to use only IPv6, prohibiting any IPv4 connections. This is only applicable for - IPv6 sockets (option <c>inet6</c>). - </p> - <p> - On most platforms this option has to be set on the socket - before associating it to an address. Therefore it is only - reasonable to give it when creating the socket and not - to use it when calling the function - (<seealso marker="#setopts/2">setopts/2</seealso>) - containing this description. - </p> - <p> - The behaviour of a socket with this socket option set to - <c>true</c> is becoming the only portable one. The original + IPv6 sockets (option <c>inet6</c>).</p> + <p>On most platforms this option must be set on the socket + before associating it to an address. It is therefore only + reasonable to specify it when creating the socket and not + to use it when calling function + (<seealso marker="#setopts/2"><c>setopts/2</c></seealso>) + containing this description.</p> + <p>The behavior of a socket with this option set to + <c>true</c> is the only portable one. The original idea when IPv6 was new of using IPv6 for all traffic is now not recommended by FreeBSD (you can use <c>{ipv6_v6only,false}</c> to override the recommended system default value), - forbidden by OpenBSD (the supported GENERIC kernel) - and impossible on Windows (that has separate + forbidden by OpenBSD (the supported GENERIC kernel), + and impossible on Windows (which has separate IPv4 and IPv6 protocol stacks). Most Linux distros still have a system default value of <c>false</c>. - This policy shift among operating systems towards - separating IPv6 from IPv4 traffic has evolved since + This policy shift among operating systems to + separate IPv6 from IPv4 traffic has evolved, as it gradually proved hard and complicated to get - a dual stack implementation correct and secure. - </p> - <p> - On some platforms the only allowed value for this option - is <c>true</c>, e.g. OpenBSD and Windows. Trying to set - this option to <c>false</c> when creating the socket - will in this case fail. - </p> - <p> - Setting this option on platforms where it does not exist - is ignored and getting this option with - <seealso marker="#getopts/2">getopts/2</seealso> - returns no value i.e the returned list will not contain an - <c>{ipv6_v6only,_}</c> tuple. On Windows the option acually - does not exist, but it is emulated as being a - read-only option with the value <c>true</c>. - </p> - <p> - So it boils down to that setting this option to <c>true</c> - when creating a socket will never fail except possibly - (at the time of this writing) on a platform where you + a dual stack implementation correct and secure.</p> + <p>On some platforms, the only allowed value for this option + is <c>true</c>, for example, OpenBSD and Windows. Trying to set + this option to <c>false</c>, when creating the socket, fails + in this case.</p> + <p>Setting this option on platforms where it does not exist + is ignored. Getting this option with + <seealso marker="#getopts/2"><c>getopts/2</c></seealso> + returns no value, that is, the returned list does not contain an + <c>{ipv6_v6only,_}</c> tuple. On Windows, the option + does not exist, but it is emulated as a + read-only option with value <c>true</c>.</p> + <p>Therefore, setting this option to <c>true</c> + when creating a socket never fails, except possibly on a + platform where you have customized the kernel to only allow <c>false</c>, - which might be doable (but weird) on e.g. OpenBSD. - </p> - <p> - If you read back the option value using - <seealso marker="#getopts/2">getopts/2</seealso> - and get no value the option does not exist in the host OS - and all bets are off regarding the behaviour of both - an IPv6 and an IPv4 socket listening on the same port - as well as for an IPv6 socket getting IPv4 traffic. - </p> + which can be doable (but awkward) on, for example, OpenBSD.</p> + <p>If you read back the option value using + <seealso marker="#getopts/2"><c>getopts/2</c></seealso> + and get no value, the option does not exist in the host + operating system. The behavior of both an IPv6 and an IPv4 + socket listening on the same port, and for an IPv6 socket + getting IPv4 traffic is then no longer predictable.</p> </item> - <tag><c>{keepalive, Boolean}</c>(TCP/IP sockets)</tag> <item> <p>Enables/disables periodic transmission on a connected - socket, when no other data is being exchanged. If + socket when no other data is exchanged. If the other end does not respond, the connection is - considered broken and an error message will be sent to - the controlling process. Default disabled.</p> - <marker id="option-linger"></marker> + considered broken and an error message is sent to + the controlling process. Defaults to <c>disabled</c>.</p> + <marker id="option-linger"></marker> + </item> + <tag><c>{linger, {true|false, Seconds}}</c></tag> + <item> + <p>Determines the time-out, in seconds, for flushing unsent data + in the <c>close/1</c> socket call. If the first component of + the value tuple is <c>false</c>, the second is ignored. This + means that <c>close/1</c> returns immediately, not waiting + for data to be flushed. Otherwise, the second component is + the flushing time-out, in seconds.</p> </item> - - <tag><c>{linger, {true|false, Seconds}}</c></tag> - <item> - <p>Determines the timeout in seconds for flushing unsent data in the - <c>close/1</c> socket call. If the 1st component of the value - tuple is <c>false</c>, the 2nd one is ignored, which means that - <c>close/1</c> returns immediately not waiting - for data to be flushed. Otherwise, the 2nd component is - the flushing time-out in seconds.</p> - </item> - <tag><c>{low_msgq_watermark, Size}</c></tag> <item> <p>If the socket message queue is in a busy state, the - socket message queue will be set in a not busy state when - the amount of data queued in the message queue falls - below this limit. Note that this limit only concerns data - that have not yet reached the ERTS internal socket - implementation. Default value used is 4 kB.</p> - <p>Senders that have been suspended due to either a - busy message queue or a busy socket, will be resumed - when neither the socket message queue, nor the socket - are busy.</p> - <p>For more information see the <c>high_msgq_watermark</c>, - <c>high_watermark</c>, and <c>low_watermark</c> options.</p> - <p>Note that distribution sockets will disable the use of - <c>high_msgq_watermark</c> and <c>low_msgq_watermark</c>, - and will instead use the - <seealso marker="erts:erlang#system_info_dist_buf_busy_limit">distribution - buffer busy limit</seealso> which is a similar feature.</p> + socket message queue is set in a not busy state when + the amount of data queued in the message queue falls + below this limit. Notice that this limit only concerns data + that has not yet reached the ERTS internal socket + implementation. Defaults to 4 kB.</p> + <p>Senders that are suspended because of either a + busy message queue or a busy socket are resumed + when the socket message queue and the socket + are not busy.</p> + <p>For more information, see options <c>high_msgq_watermark</c>, + <c>high_watermark</c>, and <c>low_watermark</c>.</p> + <p>Notice that distribution sockets disable the use of + <c>high_msgq_watermark</c> and <c>low_msgq_watermark</c>. + Instead they use the + <seealso marker="erts:erlang#system_info_dist_buf_busy_limit">distribution + buffer busy limit</seealso>, which is a similar feature.</p> </item> - <tag><c>{low_watermark, Size}</c> (TCP/IP sockets)</tag> <item> - <p>If the socket is in a busy state, the socket will - be set in a not busy state when the amount of data - queued internally by the ERTS socket implementation - falls below this limit. Default value used is 4 kB.</p> - <p>Senders that have been suspended due to either a - busy message queue or a busy socket, will be resumed - when neither the socket message queue, nor the socket - are busy.</p> - <p>For more information see the <c>high_watermark</c>, - <c>high_msgq_watermark</c>, and <c>low_msgq_watermark</c> - options.</p> + <p>If the socket is in a busy state, the socket is + set in a not busy state when the amount of data + queued internally by the ERTS socket implementation + falls below this limit. Defaults to 4 kB.</p> + <p>Senders that are suspended because of a + busy message queue or a busy socket are resumed + when the socket message queue and the socket are not busy.</p> + <p>For more information, see options <c>high_watermark</c>, + <c>high_msgq_watermark</c>, and <c>low_msgq_watermark</c>.</p> </item> - - <tag><c>{mode, Mode :: binary | list}</c></tag> + <tag><c>{mode, Mode :: binary | list}</c></tag> <item> - <p>Received <c>Packet</c> is delivered as defined by Mode.</p> - </item> - + <p>Received <c>Packet</c> is delivered as defined by <c>Mode</c>. + </p> + </item> <tag><c>{netns, Namespace :: file:filename_all()}</c></tag> <item> - <p>Set a network namespace for the socket. The <c>Namespace</c> - parameter is a filename defining the namespace for example - <c>"/var/run/netns/example"</c> typically created by the command - <c>ip netns add example</c>. This option must be used in a - function call that creates a socket i.e - <seealso marker="gen_tcp#connect/3"> - gen_tcp:connect/3,4</seealso>, - <seealso marker="gen_tcp#listen/2"> - gen_tcp:listen/2</seealso>, - <seealso marker="gen_udp#open/1"> - gen_udp:open/1,2</seealso> or - <seealso marker="gen_sctp#open/0"> - gen_sctp:open/0-2</seealso>. - </p> - <p>This option uses the Linux specific syscall - <c>setns()</c> such as in Linux kernel 3.0 or later - and therefore only exists when the runtime system - has been compiled for such an operating system. - </p> - <p> - The virtual machine also needs elevated privileges either - running as superuser or (for Linux) having the capability - <c>CAP_SYS_ADMIN</c> according to the documentation for setns(2). - However, during testing also <c>CAP_SYS_PTRACE</c> - and <c>CAP_DAC_READ_SEARCH</c> has proven to be necessary. - Example:</p><code> -setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp -</code> - <p>Note also that the filesystem containing the virtual machine - executable (<c>beam.smp</c> in the example above) has to be local, - mounted without the <c>nosetuid</c> flag, - support extended attributes and that - the kernel has to support file capabilities. - All this runs out of the box on at least Ubuntu 12.04 LTS, - except that SCTP sockets appears to not support - network namespaces. - </p> - <p>The <c>Namespace</c> is a file name and is encoded - and decoded as discussed in - <seealso marker="file">file</seealso> - except that the emulator flag <c>+fnu</c> is ignored and - <seealso marker="#getopts/2">getopts/2</seealso> - for this option will return a binary for the filename - if the stored filename can not be decoded, - which should only happen if you set the option using a binary - that can not be decoded with the emulator's filename encoding: - <seealso marker="file#native_name_encoding/0"> - file:native_name_encoding/0</seealso>. - </p> - </item> - - <tag><c>list</c></tag> + <p>Sets a network namespace for the socket. Parameter + <c>Namespace</c> is a filename defining the namespace, for + example, <c>"/var/run/netns/example"</c>, typically created by + command <c>ip netns add example</c>. This option must be used in + a function call that creates a socket, that is, + <seealso marker="gen_tcp#connect/3"><c>gen_tcp:connect/3,4</c></seealso>, + <seealso marker="gen_tcp#listen/2"><c>gen_tcp:listen/2</c></seealso>, + <seealso marker="gen_udp#open/1"><c>gen_udp:open/1,2</c></seealso>, or + <seealso marker="gen_sctp#open/0"><c>gen_sctp:open/0,1,2</c></seealso>.</p> + <p>This option uses the Linux-specific syscall + <c>setns()</c>, such as in Linux kernel 3.0 or later, + and therefore only exists when the runtime system + is compiled for such an operating system.</p> + <p>The virtual machine also needs elevated privileges, either + running as superuser or (for Linux) having capability + <c>CAP_SYS_ADMIN</c> according to the documentation for + <c>setns(2)</c>. + However, during testing also <c>CAP_SYS_PTRACE</c> + and <c>CAP_DAC_READ_SEARCH</c> have proven to be necessary.</p> + <p><em>Example:</em></p> + <code> +setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp</code> + <p>Notice that the filesystem containing the virtual machine + executable (<c>beam.smp</c> in the example) must be local, + mounted without flag <c>nosetuid</c>, + support extended attributes, and + the kernel must support file capabilities. + All this runs out of the box on at least Ubuntu 12.04 LTS, + except that SCTP sockets appear to not support + network namespaces.</p> + <p><c>Namespace</c> is a filename and is encoded + and decoded as discussed in module + <seealso marker="file">file</seealso>, with the + following exceptions:</p> + <list type="bulleted"> + <item><p>Emulator flag <c>+fnu</c> is ignored.</p></item> + <item><p><seealso marker="#getopts/2"><c>getopts/2</c></seealso> + for this option returns a binary for the filename if the stored + filename cannot be decoded. This is only to occur if you set the + option using a binary that cannot be decoded with the emulator's + filename encoding: + <seealso marker="file#native_name_encoding/0"><c>file:native_name_encoding/0</c></seealso>.</p></item> + </list> + </item> + <tag><c>list</c></tag> <item> - <p>Received <c>Packet</c> is delivered as a list.</p> - </item> - - <tag><c>binary</c></tag> + <p>Received <c>Packet</c> is delivered as a list.</p> + </item> + <tag><c>binary</c></tag> <item> - <p>Received <c>Packet</c> is delivered as a binary.</p> - </item> - + <p>Received <c>Packet</c> is delivered as a binary.</p> + </item> <tag><c>{nodelay, Boolean}</c>(TCP/IP sockets)</tag> <item> - <p>If <c>Boolean == true</c>, the <c>TCP_NODELAY</c> option - is turned on for the socket, which means that even small - amounts of data will be sent immediately.</p> + <p>If <c>Boolean == true</c>, option <c>TCP_NODELAY</c> + is turned on for the socket, which means that also small + amounts of data are sent immediately.</p> </item> <tag><c>{packet, PacketType}</c>(TCP/IP sockets)</tag> <item> <p>Defines the type of packets to use for a socket. - The following values are valid:</p> + Possible values:</p> <taglist> <tag><c>raw | 0</c></tag> <item> @@ -917,104 +920,94 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp <item> <p>Packets consist of a header specifying the number of bytes in the packet, followed by that number of bytes. - The length of header can be one, two, or four bytes; + The header length can be one, two, or four bytes, and containing an unsigned integer in big-endian byte order. - Each send operation will generate the header, and the header - will be stripped off on each receive operation.</p> - <p>In current implementation the 4-byte header is limited to 2Gb.</p> + Each send operation generates the header, and the header + is stripped off on each receive operation.</p> + <p>The 4-byte header is limited to 2Gb.</p> </item> <tag><c>asn1 | cdr | sunrm | fcgi | tpkt | line</c></tag> <item> <p>These packet types only have effect on receiving. When sending a packet, it is the responsibility of the application to supply a correct header. On - receiving, however, there will be one message sent to + receiving, however, one message is sent to the controlling process for each complete packet received, and, similarly, each call to <c>gen_tcp:recv/2,3</c> returns one complete packet. The header is <em>not</em> stripped off.</p> - <p>The meanings of the packet types are as follows: - <br></br> -<c>asn1</c> - ASN.1 BER, - <br></br> -<c>sunrm</c> - Sun's RPC encoding, - <br></br> -<c>cdr</c> - CORBA (GIOP 1.1), - <br></br> -<c>fcgi</c> - Fast CGI, - <br></br> -<c>tpkt</c> - TPKT format [RFC1006], - <br></br> -<c>line</c> - Line mode, a packet is a line - terminated with newline, lines longer than - the receive buffer are truncated.</p> - </item> + <p>The meanings of the packet types are as follows:</p> + <list type="bulleted"> + <item><c>asn1</c> - ASN.1 BER</item> + <item><c>sunrm</c> - Sun's RPC encoding</item> + <item><c>cdr</c> - CORBA (GIOP 1.1)</item> + <item><c>fcgi</c> - Fast CGI</item> + <item><c>tpkt</c> - TPKT format [RFC1006]</item> + <item><c>line</c> - Line mode, a packet is a line-terminated + with newline, lines longer than the receive buffer are + truncated</item> + </list> + </item> <tag><c>http | http_bin</c></tag> <item> <p>The Hypertext Transfer Protocol. The packets are returned with the format according to <c>HttpPacket</c> - described in <seealso marker="erts:erlang#decode_packet/3"> - erlang:decode_packet/3</seealso>. A socket in passive - mode will return <c>{ok, HttpPacket}</c> from <c>gen_tcp:recv</c> - while an active socket will send messages like <c>{http, - Socket, HttpPacket}</c>.</p> + described in + <seealso marker="erts:erlang#decode_packet/3"> + <c>erlang:decode_packet/3</c></seealso> in ERTS. + A socket in passive + mode returns <c>{ok, HttpPacket}</c> from <c>gen_tcp:recv</c> + while an active socket sends messages like + <c>{http, Socket, HttpPacket}</c>.</p> </item> <tag><c>httph | httph_bin</c></tag> <item> - <p>These two types are often not needed as the socket will - automatically switch from <c>http</c>/<c>http_bin</c> to + <p>These two types are often not needed, as the socket + automatically switches from <c>http</c>/<c>http_bin</c> to <c>httph</c>/<c>httph_bin</c> internally after the first line - has been read. There might be occasions however when they are + is read. However, there can be occasions when they are useful, such as parsing trailers from chunked encoding.</p> </item> </taglist> </item> <tag><c>{packet_size, Integer}</c>(TCP/IP sockets)</tag> <item> - <p>Sets the max allowed length of the packet body. If + <p>Sets the maximum allowed length of the packet body. If the packet header indicates that the length of the packet - is longer than the max allowed length, the packet is - considered invalid. The same happens if the packet header - is too big for the socket receive buffer.</p> - <p>For line oriented protocols (<c>line</c>,<c>http*</c>), - option <c>packet_size</c> also guarantees that lines up to the - indicated length are accepted and not considered invalid due - to internal buffer limitations.</p> + is longer than the maximum allowed length, the packet is + considered invalid. The same occurs if the packet header + is too large for the socket receive buffer.</p> + <p>For line-oriented protocols (<c>line</c>, <c>http*</c>), + option <c>packet_size</c> also guarantees that lines up to the + indicated length are accepted and not considered invalid + because of internal buffer limitations.</p> </item> <tag><c>{line_delimiter, Char}</c>(TCP/IP sockets)</tag> <item> - <p>Sets the line delimiting character for line oriented protocols - (<c>line</c>). Default value is <c>$\n</c>.</p> + <p>Sets the line delimiting character for line-oriented protocols + (<c>line</c>). Defaults to <c>$\n</c>.</p> + </item> + <tag><c>{raw, Protocol, OptionNum, ValueBin}</c></tag> + <item> + <p>See below.</p> </item> - - <tag><c>{priority, Priority}</c></tag> - <item> <p>Set the protocol-defined priority for all packets to be sent - on this socket.</p> - </item> - - <tag><c>{raw, Protocol, OptionNum, ValueBin}</c></tag> - <item> <p>See below.</p> - </item> - <tag><c>{read_packets, Integer}</c>(UDP sockets)</tag> <item> - <p>Sets the max number of UDP packets to read without + <p>Sets the maximum number of UDP packets to read without intervention from the socket when data is available. When this many packets have been read and delivered to the destination process, new packets are not read until a new notification of available data has arrived. - The default is 5, and if this parameter is set too - high the system can become unresponsive due to + Defaults to <c>5</c>. If this parameter is set too + high, the system can become unresponsive because of UDP packet flooding.</p> </item> <tag><c>{recbuf, Size}</c></tag> <item> <p>The minimum size of the receive buffer to use for the socket. You are encouraged to use - <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>, - to retrieve the actual size set by your operating system. - - </p> + <seealso marker="#getopts/2"><c>getopts/2</c></seealso> + to retrieve the size set by your operating system.</p> </item> <tag><c>{reuseaddr, Boolean}</c></tag> <item> @@ -1023,118 +1016,169 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp </item> <tag><c>{send_timeout, Integer}</c></tag> <item> - <p>Only allowed for connection oriented sockets.</p> + <p>Only allowed for connection-oriented sockets.</p> <p>Specifies a longest time to wait for a send operation to be accepted by the underlying TCP stack. When the limit is - exceeded, the send operation will return - <c>{error,timeout}</c>. How much of a packet that actually - got sent is unknown, why the socket should be closed - whenever a timeout has occurred (see <c>send_timeout_close</c>). - Default is <c>infinity</c>.</p> + exceeded, the send operation returns + <c>{error,timeout}</c>. How much of a packet that + got sent is unknown; the socket is therefore to be closed + whenever a time-out has occurred (see <c>send_timeout_close</c> + below). Defaults to <c>infinity</c>.</p> </item> <tag><c>{send_timeout_close, Boolean}</c></tag> <item> - <p>Only allowed for connection oriented sockets.</p> + <p>Only allowed for connection-oriented sockets.</p> <p>Used together with <c>send_timeout</c> to specify whether - the socket will be automatically closed when the send operation + the socket is to be automatically closed when the send operation returns <c>{error,timeout}</c>. The recommended setting is - <c>true</c> which will automatically close the socket. - Default is <c>false</c> due to backward compatibility.</p> - <marker id="option-sndbuf"></marker> + <c>true</c>, which automatically closes the socket. + Defaults to <c>false</c> because of backward compatibility.</p> + <marker id="option-sndbuf"></marker> </item> - <tag><c>{show_econnreset, Boolean}</c>(TCP/IP sockets)</tag> <item> - <p>When this option is set to <c>false</c>, as it is by - default, an RST that is received from the TCP peer is treated - as a normal close (as though a FIN was sent). A caller - to <seealso marker="gen_tcp#recv/2">gen_tcp:recv/2</seealso> - will get <c>{error, closed}</c>. In active - mode the controlling process will receive a + <p>When this option is set to <c>false</c>, which is + default, an RST received from the TCP peer is treated + as a normal close (as though an FIN was sent). A caller to + <seealso marker="gen_tcp#recv/2"><c>gen_tcp:recv/2</c></seealso> + gets <c>{error, closed}</c>. In active + mode, the controlling process receives a <c>{tcp_close, Socket}</c> message, indicating that the peer has closed the connection.</p> - <p>Setting this option to <c>true</c> will allow you to + <p>Setting this option to <c>true</c> allows you to distinguish between a connection that was closed normally, - and one which was aborted (intentionally or unintentionally) + and one that was aborted (intentionally or unintentionally) by the TCP peer. A call to - <seealso marker="gen_tcp#recv/2">gen_tcp:recv/2</seealso> - will return <c>{error, econnreset}</c>. In - active mode, the controlling process will receive a + <seealso marker="gen_tcp#recv/2"><c>gen_tcp:recv/2</c></seealso> + returns <c>{error, econnreset}</c>. In + active mode, the controlling process receives a <c>{tcp_error, Socket, econnreset}</c> message before the usual <c>{tcp_closed, Socket}</c>, as is the case for any other socket error. Calls to - <seealso marker="gen_tcp#send/2">gen_tcp:send/2</seealso> - will also return <c>{error, econnreset}</c> when it + <seealso marker="gen_tcp#send/2"><c>gen_tcp:send/2</c></seealso> + also returns <c>{error, econnreset}</c> when it is detected that a TCP peer has sent an RST.</p> <p>A connected socket returned from - <seealso marker="gen_tcp#accept/1">gen_tcp:accept/1</seealso> - will inherit the <c>show_econnreset</c> setting from the + <seealso marker="gen_tcp#accept/1"><c>gen_tcp:accept/1</c></seealso> + inherits the <c>show_econnreset</c> setting from the listening socket.</p> - <marker id="option-show_econnreset"></marker> + <marker id="option-show_econnreset"></marker> </item> - <tag><c>{sndbuf, Size}</c></tag> <item> <p>The minimum size of the send buffer to use for the socket. - You are encouraged to use - <seealso marker="inet#getopts/2"><c>inet:getopts/2</c></seealso>, - to retrieve the actual size set by your operating system. - </p> + You are encouraged to use + <seealso marker="#getopts/2"><c>getopts/2</c></seealso>, + to retrieve the size set by your operating system.</p> </item> <tag><c>{priority, Integer}</c></tag> <item> - <p>Sets the SO_PRIORITY socket level option on platforms where - this is implemented. The behaviour and allowed range varies on - different systems. The option is ignored on platforms where the - option is not implemented. Use with caution.</p> + <p>Sets the <c>SO_PRIORITY</c> socket level option on platforms + where this is implemented. The behavior and allowed range varies + between different systems. + The option is ignored on platforms where it + is not implemented. Use with caution.</p> </item> <tag><c>{tos, Integer}</c></tag> <item> - <p>Sets IP_TOS IP level options on platforms where this is - implemented. The behaviour and allowed range varies on different - systems. The option is ignored on platforms where the option is - not implemented. Use with caution.</p> + <p>Sets <c>IP_TOS IP</c> level options on platforms where this is + implemented. The behavior and allowed range varies between + different systems. + The option is ignored on platforms where it is not + implemented. Use with caution.</p> + </item> + <tag><c>{tclass, Integer}</c></tag> + <item> + <p> + Sets <c>IPV6_TCLASS IP</c> level options on platforms + where this is implemented. The behavior and allowed range + varies between different systems. + The option is ignored on platforms where it is not + implemented. Use with caution.</p> </item> </taglist> - - <p>In addition to the options mentioned above, <em>raw</em> + <p>In addition to these options, <em>raw</em> option specifications can be used. The raw options are - specified as a tuple of arity four, beginning with the tag - <c>raw</c>, followed by the protocol level, the option number - and the actual option value specified as a binary. This - corresponds to the second, third and fourth argument to the + specified as a tuple of arity four, beginning with tag + <c>raw</c>, followed by the protocol level, the option number, + and the option value specified as a binary. This + corresponds to the second, third, and fourth arguments to the <c>setsockopt</c> call in the C socket API. The option value - needs to be coded in the native endianess of the platform and, - if a structure is required, needs to follow the struct + must be coded in the native endianess of the platform and, + if a structure is required, must follow the structure alignment conventions on the specific platform.</p> - <p>Using raw socket options require detailed knowledge about + <p>Using raw socket options requires detailed knowledge about the current operating system and TCP stack.</p> - <p>As an example of the usage of raw options, consider a Linux - system where you want to set the <c>TCP_LINGER2</c> option on - the <c>IPPROTO_TCP</c> protocol level in the stack. You know + <p><em>Example:</em></p> + <p>This example concerns the use of raw options. Consider a Linux + system where you want to set option <c>TCP_LINGER2</c> on + protocol level <c>IPPROTO_TCP</c> in the stack. You know that on this particular system it defaults to 60 (seconds), - but you would like to lower it to 30 for a particular - socket. The <c>TCP_LINGER2</c> option is not explicitly - supported by inet, but you know that the protocol level - translates to the number 6, the option number to the number 8 - and the value is to be given as a 32 bit integer. You can use - this line of code to set the option for the socket named + but you want to lower it to 30 for a particular + socket. Option <c>TCP_LINGER2</c> is not explicitly + supported by <c>inet</c>, but you know that the protocol level + translates to number 6, the option number to number 8, + and the value is to be specified as a 32-bit integer. You can use + this code line to set the option for the socket named <c>Sock</c>:</p> <code type="none"><![CDATA[ - inet:setopts(Sock,[{raw,6,8,<<30:32/native>>}]),]]></code> +inet:setopts(Sock,[{raw,6,8,<<30:32/native>>}]),]]></code> <p>As many options are silently discarded by the stack if they - are given out of range, it could be a good idea to check that - a raw option really got accepted. This code places the value - in the variable TcpLinger2:</p> + are specified out of range; it can be a good idea to check that + a raw option is accepted. The following code places the value + in variable <c>TcpLinger2:</c></p> <code type="none"><![CDATA[ - {ok,[{raw,6,8,<<TcpLinger2:32/native>>}]}=inet:getopts(Sock,[{raw,6,8,4}]),]]></code> - <p>Code such as the examples above is inherently non portable, - even different versions of the same OS on the same platform - may respond differently to this kind of option +{ok,[{raw,6,8,<<TcpLinger2:32/native>>}]}=inet:getopts(Sock,[{raw,6,8,4}]),]]></code> + <p>Code such as these examples is inherently non-portable, + even different versions of the same OS on the same platform + can respond differently to this kind of option manipulation. Use with care.</p> - <p>Note that the default options for TCP/IP sockets can be + <p>Notice that the default options for TCP/IP sockets can be changed with the Kernel configuration parameters mentioned in - the beginning of this document.</p> + the beginning of this manual page.</p> + </desc> + </func> + + <func> + <name name="sockname" arity="1"/> + <fsummary>Return the local address and port number for a socket. + </fsummary> + <desc> + <p>Returns the local address and port number for a socket.</p> + <p>Notice that for SCTP sockets this function returns only + one of the socket addresses. Function + <seealso marker="#socknames/1"><c>socknames/1,2</c></seealso> + returns all.</p> + </desc> + </func> + + <func> + <name name="socknames" arity="1"/> + <fsummary>Return all local address/port numbers for a socket.</fsummary> + <desc> + <p>Equivalent to + <seealso marker="#socknames/2"><c>socknames(<anno>Socket</anno>, 0)</c></seealso>. + </p> + </desc> + </func> + + <func> + <name name="socknames" arity="2"/> + <fsummary>Return all local address/port numbers for a socket.</fsummary> + <desc> + <p>Returns a list of all local address/port number pairs for a socket + for the specified association <c><anno>Assoc</anno></c>.</p> + <p>This function can return multiple addresses for multihomed + sockets, such as SCTP sockets. For other sockets it + returns a one-element list.</p> + <p>Notice that parameter <c><anno>Assoc</anno></c> is by the + <url href="http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13">SCTP Sockets API Extensions</url> + defined to be ignored for one-to-one style sockets. + For one-to-many style sockets, the special value <c>0</c> + is defined to mean that the returned addresses must be + without any particular association. + How different SCTP implementations interprets this varies somewhat. + </p> </desc> </func> </funcs> @@ -1143,149 +1187,147 @@ setcap cap_sys_admin,cap_sys_ptrace,cap_dac_read_search+epi beam.smp <marker id="error_codes"></marker> <title>POSIX Error Codes</title> <list type="bulleted"> - <item><c>e2big</c> - argument list too long</item> - <item><c>eacces</c> - permission denied</item> - <item><c>eaddrinuse</c> - address already in use</item> - <item><c>eaddrnotavail</c> - cannot assign requested address</item> - <item><c>eadv</c> - advertise error</item> - <item><c>eafnosupport</c> - address family not supported by - protocol family</item> - <item><c>eagain</c> - resource temporarily unavailable</item> + <item><c>e2big</c> - Too long argument list</item> + <item><c>eacces</c> - Permission denied</item> + <item><c>eaddrinuse</c> - Address already in use</item> + <item><c>eaddrnotavail</c> - Cannot assign requested address</item> + <item><c>eadv</c> - Advertise error</item> + <item><c>eafnosupport</c> - Address family not supported by + protocol family</item> + <item><c>eagain</c> - Resource temporarily unavailable</item> <item><c>ealign</c> - EALIGN</item> - <item><c>ealready</c> - operation already in progress</item> - <item><c>ebade</c> - bad exchange descriptor</item> - <item><c>ebadf</c> - bad file number</item> - <item><c>ebadfd</c> - file descriptor in bad state</item> - <item><c>ebadmsg</c> - not a data message</item> - <item><c>ebadr</c> - bad request descriptor</item> - <item><c>ebadrpc</c> - RPC structure is bad</item> - <item><c>ebadrqc</c> - bad request code</item> - <item><c>ebadslt</c> - invalid slot</item> - <item><c>ebfont</c> - bad font file format</item> - <item><c>ebusy</c> - file busy</item> - <item><c>echild</c> - no children</item> - <item><c>echrng</c> - channel number out of range</item> - <item><c>ecomm</c> - communication error on send</item> - <item><c>econnaborted</c> - software caused connection abort</item> - <item><c>econnrefused</c> - connection refused</item> - <item><c>econnreset</c> - connection reset by peer</item> - <item><c>edeadlk</c> - resource deadlock avoided</item> - <item><c>edeadlock</c> - resource deadlock avoided</item> - <item><c>edestaddrreq</c> - destination address required</item> - <item><c>edirty</c> - mounting a dirty fs w/o force</item> - <item><c>edom</c> - math argument out of range</item> - <item><c>edotdot</c> - cross mount point</item> - <item><c>edquot</c> - disk quota exceeded</item> - <item><c>eduppkg</c> - duplicate package name</item> - <item><c>eexist</c> - file already exists</item> - <item><c>efault</c> - bad address in system call argument</item> - <item><c>efbig</c> - file too large</item> - <item><c>ehostdown</c> - host is down</item> - <item><c>ehostunreach</c> - host is unreachable</item> - <item><c>eidrm</c> - identifier removed</item> - <item><c>einit</c> - initialization error</item> - <item><c>einprogress</c> - operation now in progress</item> - <item><c>eintr</c> - interrupted system call</item> - <item><c>einval</c> - invalid argument</item> + <item><c>ealready</c> - Operation already in progress</item> + <item><c>ebade</c> - Bad exchange descriptor</item> + <item><c>ebadf</c> - Bad file number</item> + <item><c>ebadfd</c> - File descriptor in bad state</item> + <item><c>ebadmsg</c> - Not a data message</item> + <item><c>ebadr</c> - Bad request descriptor</item> + <item><c>ebadrpc</c> - Bad RPC structure</item> + <item><c>ebadrqc</c> - Bad request code</item> + <item><c>ebadslt</c> - Invalid slot</item> + <item><c>ebfont</c> - Bad font file format</item> + <item><c>ebusy</c> - File busy</item> + <item><c>echild</c> - No children</item> + <item><c>echrng</c> - Channel number out of range</item> + <item><c>ecomm</c> - Communication error on send</item> + <item><c>econnaborted</c> - Software caused connection abort</item> + <item><c>econnrefused</c> - Connection refused</item> + <item><c>econnreset</c> - Connection reset by peer</item> + <item><c>edeadlk</c> - Resource deadlock avoided</item> + <item><c>edeadlock</c> - Resource deadlock avoided</item> + <item><c>edestaddrreq</c> - Destination address required</item> + <item><c>edirty</c> - Mounting a dirty fs without force</item> + <item><c>edom</c> - Math argument out of range</item> + <item><c>edotdot</c> - Cross mount point</item> + <item><c>edquot</c> - Disk quota exceeded</item> + <item><c>eduppkg</c> - Duplicate package name</item> + <item><c>eexist</c> - File already exists</item> + <item><c>efault</c> - Bad address in system call argument</item> + <item><c>efbig</c> - File too large</item> + <item><c>ehostdown</c> - Host is down</item> + <item><c>ehostunreach</c> - Host is unreachable</item> + <item><c>eidrm</c> - Identifier removed</item> + <item><c>einit</c> - Initialization error</item> + <item><c>einprogress</c> - Operation now in progress</item> + <item><c>eintr</c> - Interrupted system call</item> + <item><c>einval</c> - Invalid argument</item> <item><c>eio</c> - I/O error</item> - <item><c>eisconn</c> - socket is already connected</item> - <item><c>eisdir</c> - illegal operation on a directory</item> - <item><c>eisnam</c> - is a named file</item> - <item><c>el2hlt</c> - level 2 halted</item> - <item><c>el2nsync</c> - level 2 not synchronized</item> - <item><c>el3hlt</c> - level 3 halted</item> - <item><c>el3rst</c> - level 3 reset</item> + <item><c>eisconn</c> - Socket is already connected</item> + <item><c>eisdir</c> - Illegal operation on a directory</item> + <item><c>eisnam</c> - Is a named file</item> + <item><c>el2hlt</c> - Level 2 halted</item> + <item><c>el2nsync</c> - Level 2 not synchronized</item> + <item><c>el3hlt</c> - Level 3 halted</item> + <item><c>el3rst</c> - Level 3 reset</item> <item><c>elbin</c> - ELBIN</item> - <item><c>elibacc</c> - cannot access a needed shared library</item> - <item><c>elibbad</c> - accessing a corrupted shared library</item> - <item><c>elibexec</c> - cannot exec a shared library directly</item> - <item><c>elibmax</c> - attempting to link in more shared - libraries than system limit</item> - <item><c>elibscn</c> - .lib section in a.out corrupted</item> - <item><c>elnrng</c> - link number out of range</item> - <item><c>eloop</c> - too many levels of symbolic links</item> - <item><c>emfile</c> - too many open files</item> - <item><c>emlink</c> - too many links</item> - <item><c>emsgsize</c> - message too long</item> - <item><c>emultihop</c> - multihop attempted</item> - <item><c>enametoolong</c> - file name too long</item> - <item><c>enavail</c> - not available</item> + <item><c>elibacc</c> - Cannot access a needed shared library</item> + <item><c>elibbad</c> - Accessing a corrupted shared library</item> + <item><c>elibexec</c> - Cannot exec a shared library directly</item> + <item><c>elibmax</c> - Attempting to link in more shared + libraries than system limit</item> + <item><c>elibscn</c> - <c>.lib</c> section in <c>a.out</c> + corrupted</item> + <item><c>elnrng</c> - Link number out of range</item> + <item><c>eloop</c> - Too many levels of symbolic links</item> + <item><c>emfile</c> - Too many open files</item> + <item><c>emlink</c> - Too many links</item> + <item><c>emsgsize</c> - Message too long</item> + <item><c>emultihop</c> - Multihop attempted</item> + <item><c>enametoolong</c> - Filename too long</item> + <item><c>enavail</c> - Unavailable</item> <item><c>enet</c> - ENET</item> - <item><c>enetdown</c> - network is down</item> - <item><c>enetreset</c> - network dropped connection on reset</item> - <item><c>enetunreach</c> - network is unreachable</item> - <item><c>enfile</c> - file table overflow</item> - <item><c>enoano</c> - anode table overflow</item> - <item><c>enobufs</c> - no buffer space available</item> - <item><c>enocsi</c> - no CSI structure available</item> - <item><c>enodata</c> - no data available</item> - <item><c>enodev</c> - no such device</item> - <item><c>enoent</c> - no such file or directory</item> - <item><c>enoexec</c> - exec format error</item> - <item><c>enolck</c> - no locks available</item> - <item><c>enolink</c> - link has be severed</item> - <item><c>enomem</c> - not enough memory</item> - <item><c>enomsg</c> - no message of desired type</item> - <item><c>enonet</c> - machine is not on the network</item> - <item><c>enopkg</c> - package not installed</item> - <item><c>enoprotoopt</c> - bad protocol option</item> - <item><c>enospc</c> - no space left on device</item> - <item><c>enosr</c> - out of stream resources or not a stream - device</item> - <item><c>enosym</c> - unresolved symbol name</item> - <item><c>enosys</c> - function not implemented</item> - <item><c>enotblk</c> - block device required</item> - <item><c>enotconn</c> - socket is not connected</item> - <item><c>enotdir</c> - not a directory</item> - <item><c>enotempty</c> - directory not empty</item> - <item><c>enotnam</c> - not a named file</item> - <item><c>enotsock</c> - socket operation on non-socket</item> - <item><c>enotsup</c> - operation not supported</item> - <item><c>enotty</c> - inappropriate device for ioctl</item> - <item><c>enotuniq</c> - name not unique on network</item> - <item><c>enxio</c> - no such device or address</item> - <item><c>eopnotsupp</c> - operation not supported on socket</item> - <item><c>eperm</c> - not owner</item> - <item><c>epfnosupport</c> - protocol family not supported</item> - <item><c>epipe</c> - broken pipe</item> - <item><c>eproclim</c> - too many processes</item> - <item><c>eprocunavail</c> - bad procedure for program</item> - <item><c>eprogmismatch</c> - program version wrong</item> - <item><c>eprogunavail</c> - RPC program not available</item> - <item><c>eproto</c> - protocol error</item> - <item><c>eprotonosupport</c> - protocol not supported</item> - <item><c>eprototype</c> - protocol wrong type for socket</item> - <item><c>erange</c> - math result unrepresentable</item> + <item><c>enetdown</c> - Network is down</item> + <item><c>enetreset</c> - Network dropped connection on reset</item> + <item><c>enetunreach</c> - Network is unreachable</item> + <item><c>enfile</c> - File table overflow</item> + <item><c>enoano</c> - Anode table overflow</item> + <item><c>enobufs</c> - No buffer space available</item> + <item><c>enocsi</c> - No CSI structure available</item> + <item><c>enodata</c> - No data available</item> + <item><c>enodev</c> - No such device</item> + <item><c>enoent</c> - No such file or directory</item> + <item><c>enoexec</c> - Exec format error</item> + <item><c>enolck</c> - No locks available</item> + <item><c>enolink</c> - Link has been severed</item> + <item><c>enomem</c> - Not enough memory</item> + <item><c>enomsg</c> - No message of desired type</item> + <item><c>enonet</c> - Machine is not on the network</item> + <item><c>enopkg</c> - Package not installed</item> + <item><c>enoprotoopt</c> - Bad protocol option</item> + <item><c>enospc</c> - No space left on device</item> + <item><c>enosr</c> - Out of stream resources or not a stream device</item> + <item><c>enosym</c> - Unresolved symbol name</item> + <item><c>enosys</c> - Function not implemented</item> + <item><c>enotblk</c> - Block device required</item> + <item><c>enotconn</c> - Socket is not connected</item> + <item><c>enotdir</c> - Not a directory</item> + <item><c>enotempty</c> - Directory not empty</item> + <item><c>enotnam</c> - Not a named file</item> + <item><c>enotsock</c> - Socket operation on non-socket</item> + <item><c>enotsup</c> - Operation not supported</item> + <item><c>enotty</c> - Inappropriate device for <c>ioctl</c></item> + <item><c>enotuniq</c> - Name not unique on network</item> + <item><c>enxio</c> - No such device or address</item> + <item><c>eopnotsupp</c> - Operation not supported on socket</item> + <item><c>eperm</c> - Not owner</item> + <item><c>epfnosupport</c> - Protocol family not supported</item> + <item><c>epipe</c> - Broken pipe</item> + <item><c>eproclim</c> - Too many processes</item> + <item><c>eprocunavail</c> - Bad procedure for program</item> + <item><c>eprogmismatch</c> - Wrong program version</item> + <item><c>eprogunavail</c> - RPC program unavailable</item> + <item><c>eproto</c> - Protocol error</item> + <item><c>eprotonosupport</c> - Protocol not supported</item> + <item><c>eprototype</c> - Wrong protocol type for socket</item> + <item><c>erange</c> - Math result unrepresentable</item> <item><c>erefused</c> - EREFUSED</item> - <item><c>eremchg</c> - remote address changed</item> - <item><c>eremdev</c> - remote device</item> - <item><c>eremote</c> - pathname hit remote file system</item> - <item><c>eremoteio</c> - remote i/o error</item> + <item><c>eremchg</c> - Remote address changed</item> + <item><c>eremdev</c> - Remote device</item> + <item><c>eremote</c> - Pathname hit remote filesystem</item> + <item><c>eremoteio</c> - Remote I/O error</item> <item><c>eremoterelease</c> - EREMOTERELEASE</item> - <item><c>erofs</c> - read-only file system</item> - <item><c>erpcmismatch</c> - RPC version is wrong</item> - <item><c>erremote</c> - object is remote</item> - <item><c>eshutdown</c> - cannot send after socket shutdown</item> - <item><c>esocktnosupport</c> - socket type not supported</item> - <item><c>espipe</c> - invalid seek</item> - <item><c>esrch</c> - no such process</item> - <item><c>esrmnt</c> - srmount error</item> - <item><c>estale</c> - stale remote file handle</item> + <item><c>erofs</c> - Read-only filesystem</item> + <item><c>erpcmismatch</c> - Wrong RPC version</item> + <item><c>erremote</c> - Object is remote</item> + <item><c>eshutdown</c> - Cannot send after socket shutdown</item> + <item><c>esocktnosupport</c> - Socket type not supported</item> + <item><c>espipe</c> - Invalid seek</item> + <item><c>esrch</c> - No such process</item> + <item><c>esrmnt</c> - Srmount error</item> + <item><c>estale</c> - Stale remote file handle</item> <item><c>esuccess</c> - Error 0</item> - <item><c>etime</c> - timer expired</item> - <item><c>etimedout</c> - connection timed out</item> - <item><c>etoomanyrefs</c> - too many references</item> - <item><c>etxtbsy</c> - text file or pseudo-device busy</item> - <item><c>euclean</c> - structure needs cleaning</item> - <item><c>eunatch</c> - protocol driver not attached</item> - <item><c>eusers</c> - too many users</item> - <item><c>eversion</c> - version mismatch</item> - <item><c>ewouldblock</c> - operation would block</item> - <item><c>exdev</c> - cross-domain link</item> - <item><c>exfull</c> - message tables full</item> - <item><c>nxdomain</c> - the hostname or domain name could not be - found</item> + <item><c>etime</c> - Timer expired</item> + <item><c>etimedout</c> - Connection timed out</item> + <item><c>etoomanyrefs</c> - Too many references</item> + <item><c>etxtbsy</c> - Text file or pseudo-device busy</item> + <item><c>euclean</c> - Structure needs cleaning</item> + <item><c>eunatch</c> - Protocol driver not attached</item> + <item><c>eusers</c> - Too many users</item> + <item><c>eversion</c> - Version mismatch</item> + <item><c>ewouldblock</c> - Operation would block</item> + <item><c>exdev</c> - Cross-domain link</item> + <item><c>exfull</c> - Message tables full</item> + <item><c>nxdomain</c> - Hostname or domain name cannot be found</item> </list> </section> </erlref> - |