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diff --git a/erts/doc/src/socket_usage.xml b/erts/doc/src/socket_usage.xml new file mode 100644 index 0000000000..c3cda9a615 --- /dev/null +++ b/erts/doc/src/socket_usage.xml @@ -0,0 +1,845 @@ +<?xml version="1.0" encoding="utf-8" ?> +<!DOCTYPE chapter SYSTEM "chapter.dtd"> + +<chapter> + <header> + <copyright> + <year>2018</year><year>2019</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 + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + + </legalnotice> + + <title>Socket Usage</title> + <prepared>Micael Karlberg</prepared> + <docno></docno> + <date>2018-07-17</date> + <rev>PA1</rev> + <file>socket_usage.xml</file> + </header> + + <section> + <title>Introduction</title> + <p>The socket interface (module) is basically an "thin" layer on top of + the OS socket interface. It is assumed that, unless you have special needs, + gen_[tcp|udp|sctp] should be sufficent (when they become available). </p> + <p>Note that just because we have a documented and described option, + it does <em>not</em> mean that the OS supports it. So its recommended + that the user reads the platform specific documentation for the + option used. </p> + <section> + <title>Asynchronous calls</title> + <p>Some functions allow for an <i>asynchronous</i> call + (<seealso marker="socket#accept_async"><c>accept/2</c></seealso>, + <seealso marker="socket#connect_async"><c>connect/3</c></seealso>, + <seealso marker="socket#recv_async"><c>recv/3,4</c></seealso>, + <seealso marker="socket#recvfrom_async"><c>recvfrom/3,4</c></seealso>, + <seealso marker="socket#recvmsg_async"><c>recvmsg/2,3,5</c></seealso>, + <seealso marker="socket#send_async"><c>send/3,4</c></seealso>, + <seealso marker="socket#sendmsg_async"><c>sendmsg/3,4</c></seealso> and + <seealso marker="socket#sendto_async"><c>sendto/4,5</c></seealso>). + This is achieved by setting the <c>Timeout</c> argument to + <c>nowait</c>. For instance, if calling the + <seealso marker="socket#recv_async"><c>recv/3</c></seealso> + function with Timeout set to <c>nowait</c> (i.e. + <c>recv(Sock, 0, nowait)</c>) + when there is actually nothing to read, it will return with + <c>{select, </c> + <seealso marker="socket#type-select_info"><c>SelectInfo</c></seealso><c>}</c> + (<c>SelectInfo</c> contains the + <seealso marker="socket#type-select_ref">SelectRef</seealso>). + When data eventually arrives a 'select message' + will be sent to the caller:</p> + <taglist> + <!-- NOTE THAT THE EMPTY TAG IS INTENTIONAL --> + <tag></tag> + <item><c>{'$socket', socket(), select, SelectRef}</c></item> + </taglist> + <p>The caller can then make another + call to the recv function and now expect data.</p> + <p>The user must also be prepared to receive an abort message: </p> + <taglist> + <!-- NOTE THAT THE EMPTY TAG IS INTENTIONAL --> + <tag></tag> + <item><c>{'$socket', socket(), abort, Info}</c></item> + </taglist> + <p>If the operation is aborted + for whatever reason (e.g. if the socket is closed "by someone else"). + The <c>Info</c> part contains the abort reason (in this case that + the socket has been closed <c>Info = {SelectRef, closed}</c>). </p> + <p>Note that all other users are <em>locked out</em> until the + 'current user' has called the function (recv in this case). So either + immediately call the function or + <seealso marker="socket#cancel/2"><c>cancel</c></seealso>. </p> + + <p>The general form of the 'socket' message is: </p> + <taglist> + <!-- NOTE THAT THE EMPTY TAG IS INTENTIONAL --> + <tag></tag> + <item><c>{'$socket', Sock :: socket(), Tag :: atom(), Info :: term()}</c></item> + </taglist> + <p>Where the format of <c>Info</c> is a function of <c>Tag</c>:</p> + <table> + <row> + <cell><em>Tag</em></cell> + <cell><em>Info value type</em></cell> + </row> + <row> + <cell>select</cell> + <cell>select_ref()</cell> + </row> + <row> + <cell>abort</cell> + <cell>{select_ref(), Reason :: term()}</cell> + </row> + <tcaption>socket message info value type</tcaption> + </table> + <p>The <c>select_ref()</c> is the same as was received in the + <seealso marker="socket#type-select_info"><c>SelectInfo</c></seealso>. </p> + </section> + </section> + + <section> + <marker id="socket_options"></marker> + <title>Socket Options</title> + + <p>Options for level <c>otp</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>assoc_id</cell> + <cell>integer()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell>type = seqpacket, protocol = sctp, is an association</cell> + </row> + <row> + <cell>debug</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>iow</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>controlling_process</cell> + <cell>pid()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>rcvbuf</cell> + <cell>default | pos_integer() | {pos_integer(), pos_ineteger()}</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>'default' only valid for set. + The tuple form is only valid for type 'stream' and protocol 'tcp'.</cell> + </row> + <row> + <cell>rcvctrlbuf</cell> + <cell>default | pos_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>default only valid for set</cell> + </row> + <row> + <cell>sndctrlbuf</cell> + <cell>default | pos_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>default only valid for set</cell> + </row> + <row> + <cell>fd</cell> + <cell>integer()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <tcaption>option levels</tcaption> + </table> + + <p>Options for level <c>socket</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>acceptconn</cell> + <cell>boolean()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>bindtodevice</cell> + <cell>string()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>Before Linux 3.8, this socket option could be set, but not get. + Only works for some socket types (e.g. <c>inet</c>). + If empty value is set, the binding is removed.</cell> + </row> + <row> + <cell>broadcast</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram</cell> + </row> + <row> + <cell>debug</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>may require admin capability</cell> + </row> + <row> + <cell>domain</cell> + <cell>domain()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell><em>Not</em> on FreeBSD (for instance)</cell> + </row> + <row> + <cell>dontroute</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>keepalive</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>linger</cell> + <cell>abort | linger()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>oobinline</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>peek_off</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>domain = local (unix)</cell> + </row> + <row> + <cell>priority</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>protocol</cell> + <cell>protocol()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell><em>Not</em> on (some) Darwin (for instance)</cell> + </row> + <row> + <cell>rcvbuf</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>rcvlowat</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>rcvtimeo</cell> + <cell>timeval()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>reuseaddr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>reuseport</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>domain = inet | inet6</cell> + </row> + <row> + <cell>sndbuf</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>sndlowat</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>not changeable on Linux</cell> + </row> + <row> + <cell>sndtimeo</cell> + <cell>timeval()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>timestamp</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>type</cell> + <cell>type()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <tcaption>socket options</tcaption> + </table> + + <p>Options for level <c>ip</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>add_membership</cell> + <cell>ip_mreq()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>add_source_membership</cell> + <cell>ip_mreq_source()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>block_source</cell> + <cell>ip_mreq_source()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>drop_membership</cell> + <cell>ip_mreq()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>drop_source_membership</cell> + <cell>ip_mreq_source()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>freebind</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>hdrincl</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>minttl</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>msfilter</cell> + <cell>null | ip_msfilter()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>mtu</cell> + <cell>integer()</cell> + <cell>no</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>mtu_discover</cell> + <cell>ip_pmtudisc()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_all</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_if</cell> + <cell>any | ip4_address()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_loop</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_ttl</cell> + <cell>uint8()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>nodefrag</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>pktinfo</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram</cell> + </row> + <row> + <cell>recvdstaddr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram</cell> + </row> + <row> + <cell>recverr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>recvif</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw</cell> + </row> + <row> + <cell>recvopts</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type =/= stream</cell> + </row> + <row> + <cell>recvorigdstaddr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>recvttl</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type =/= stream</cell> + </row> + <row> + <cell>retopts</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type =/= stream</cell> + </row> + <row> + <cell>router_alert</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>sendsrcaddr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>tos</cell> + <cell>ip_tos()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>some high-priority levels may require superuser capability</cell> + </row> + <row> + <cell>transparent</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>requires admin capability</cell> + </row> + <row> + <cell>ttl</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>unblock_source</cell> + <cell>ip_mreq_source()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <tcaption>ip options</tcaption> + </table> + + <p>Options for level <c>ipv6</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>addrform</cell> + <cell>inet</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>allowed only for IPv6 sockets that are connected and bound to a + v4-mapped-on-v6 address</cell> + </row> + <row> + <cell>add_membership</cell> + <cell>ipv6_mreq()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>authhdr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, obsolete?</cell> + </row> + <row> + <cell>drop_membership</cell> + <cell>ipv6_mreq()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>dstopts</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, requires superuser privileges to update</cell> + </row> + <row> + <cell>flowinfo</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, requires superuser privileges to update</cell> + </row> + <row> + <cell>hoplimit</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, requires superuser privileges to update</cell> + </row> + <row> + <cell>hopopts</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, requires superuser privileges to update</cell> + </row> + <row> + <cell>mtu</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>Get: Only after the socket has been connected</cell> + </row> + <row> + <cell>mtu_discover</cell> + <cell>ipv6_pmtudisc()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_hops</cell> + <cell>default | uint8()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>multicast_if</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw</cell> + </row> + <row> + <cell>multicast_loop</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>recverr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>recvpktinfo | pktinfo</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw</cell> + </row> + <row> + <cell>router_alert</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = raw</cell> + </row> + <row> + <cell>rthdr</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>type = dgram | raw, requires superuser privileges to update</cell> + </row> + <row> + <cell>unicast_hops</cell> + <cell>default | uint8()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>v6only</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <tcaption>ipv6 options</tcaption> + </table> + + <p>Options for level <c>tcp</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>congestion</cell> + <cell>string()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>maxseg</cell> + <cell>integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>nodelay</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <tcaption>tcp options</tcaption> + </table> + + <p>Options for level <c>udp</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>cork</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <tcaption>udp options</tcaption> + </table> + + <p>Options for level <c>sctp</c>: </p> + <table> + <row> + <cell><em>Option Name</em></cell> + <cell><em>Value Type</em></cell> + <cell><em>Set</em></cell> + <cell><em>Get</em></cell> + <cell><em>Other Requirements and comments</em></cell> + </row> + <row> + <cell>associnfo</cell> + <cell>sctp_assocparams()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>autoclose</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>disable_fragments</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>events</cell> + <cell>sctp_event_subscribe()</cell> + <cell>yes</cell> + <cell>no</cell> + <cell>none</cell> + </row> + <row> + <cell>initmsg</cell> + <cell>sctp_initmsg()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>maxseg</cell> + <cell>non_neg_integer()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>nodelay</cell> + <cell>boolean()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <row> + <cell>rtoinfo</cell> + <cell>sctp_rtoinfo()</cell> + <cell>yes</cell> + <cell>yes</cell> + <cell>none</cell> + </row> + <tcaption>sctp options</tcaption> + </table> + + </section> +</chapter> + |