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Diffstat (limited to 'erts/doc/src/erl_dist_protocol.xml')
| -rw-r--r-- | erts/doc/src/erl_dist_protocol.xml | 199 |
1 files changed, 185 insertions, 14 deletions
diff --git a/erts/doc/src/erl_dist_protocol.xml b/erts/doc/src/erl_dist_protocol.xml index ee74983730..f924c8a70b 100644 --- a/erts/doc/src/erl_dist_protocol.xml +++ b/erts/doc/src/erl_dist_protocol.xml @@ -5,7 +5,7 @@ <header> <copyright> <year>2007</year> - <year>2016</year> + <year>2018</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> @@ -70,6 +70,17 @@ <p>The integers in all multibyte fields are in big-endian order.</p> + <warning> + <p> + The Erlang Distribution protocol is not by itself secure and does not + aim to be so. In order to get secure distribution the distributed nodes + should be configured to use distribution over tls. + See the <seealso marker="ssl:ssl_distribution"> + Using SSL for Erlang Distribution</seealso> User's Guide + for details on how to setup a secure distributed node. + </p> + </warning> + <section> <title>EPMD Protocol</title> <p>The requests served by the EPMD are summarized in the following @@ -521,11 +532,7 @@ io:format("old/unused name ~ts at port ~p, fd = ~p ~n", <marker id="distribution_handshake"/> <title>Distribution Handshake</title> <p>This section describes the distribution handshake protocol introduced - in Erlang/OTP R6. This description was previously located in - <c>$ERL_TOP/lib/kernel/internal_doc/distribution_handshake.txt</c> and - has more or less been copied and "formatted" here. It has been almost - unchanged since 1999, but the handshake has not changed much since then - either.</p> + in Erlang/OTP R6. The handshake has remained almost the same since then.</p> <section> <title>General</title> @@ -818,14 +825,54 @@ DiB == gen_digest(ChA, ICA)? <item> <p>The node understand UTF-8 encoded atoms.</p> </item> + <tag><c>-define(DFLAG_MAP_TAG, 16#20000).</c></tag> + <item> + <p>The node understand the map tag.</p> + </item> + <tag><c>-define(DFLAG_BIG_CREATION, 16#40000).</c></tag> + <item> + <p>The node understand big node creation.</p> + </item> + <tag><c>-define(DFLAG_SEND_SENDER, 16#80000).</c></tag> + <item> + <p> + Use the <c>SEND_SENDER</c> + <seealso marker="#control_message">control message</seealso> + instead of the <c>SEND</c> control message and use the + <c>SEND_SENDER_TT</c> control message instead + of the <c>SEND_TT</c> control message. + </p> + </item> + <tag><c>-define(DFLAG_BIG_SEQTRACE_LABELS, 16#100000).</c></tag> + <item> + <p>The node understands any term as the seqtrace label.</p> + </item> + <tag><c>-define(DFLAG_EXIT_PAYLOAD, 16#400000).</c></tag> + <item> + <p>Use the <c>PAYLOAD_EXIT</c>, <c>PAYLOAD_EXIT_TT</c>, + <c>PAYLOAD_EXIT2</c>, <c>PAYLOAD_EXIT2_TT</c> + and <c>PAYLOAD_MONITOR_P_EXIT</c> + <seealso marker="#control_message">control message</seealso>s + instead of the non-PAYLOAD variants.</p> + </item> + <tag><c>-define(DFLAG_FRAGMENTS, 16#800000).</c></tag> + <item> + <p>Use <seealso marker="erl_ext_dist#fragments">fragmented</seealso> + distribution messages to send large messages.</p> + </item> </taglist> + <p> + There is also function <c>dist_util:strict_order_flags/0</c> + returning all flags (bitwise or:ed together) corresponding to features + that require strict ordering of data over distribution channels. + </p> </section> </section> <section> <marker id="connected_nodes"/> <title>Protocol between Connected Nodes</title> - <p>As from ERTS 5.7.2 the runtime system passes a distribution flag + <p>Since ERTS 5.7.2 (OTP R13B) the runtime system passes a distribution flag in the handshake stage that enables the use of a <seealso marker="erl_ext_dist#distribution_header">distribution header </seealso> on all messages passed. Messages passed between nodes have in @@ -844,7 +891,7 @@ DiB == gen_digest(ChA, ICA)? <cell align="center"><c>ControlMessage</c></cell> <cell align="center"><c>Message</c></cell> </row> - <tcaption>Format of Messages Passed between Nodes (as from ERTS 5.7.2) + <tcaption>Format of Messages Passed between Nodes (as from ERTS 5.7.2 (OTP R13B)) </tcaption> </table> @@ -853,15 +900,23 @@ DiB == gen_digest(ChA, ICA)? <item> <p>Equal to d + n + m.</p> </item> + <tag><c>DistributionHeader</c></tag> + <item> + <p> + <seealso marker="erl_ext_dist#distribution_header">Distribution header + describing the atom cache and fragmented distribution messages. + </seealso> + </p> + </item> <tag><c>ControlMessage</c></tag> <item> <p>A tuple passed using the external format of Erlang.</p> </item> <tag><c>Message</c></tag> <item> - <p>The message sent to another node using the '!' (in external format). - Notice that <c>Message</c> is only passed in combination with a - <c>ControlMessage</c> encoding a send ('!').</p> + <p>The message sent to another node using the '!' + or the reason for a EXIT, EXIT2 or DOWN signal using + the external term format.</p> </item> </taglist> @@ -869,7 +924,7 @@ DiB == gen_digest(ChA, ICA)? number is omitted from the terms that follow a distribution header </seealso>.</p> - <p>Nodes with an ERTS version earlier than 5.7.2 does not pass the + <p>Nodes with an ERTS version earlier than 5.7.2 (OTP R13B) does not pass the distribution flag that enables the distribution header. Messages passed between nodes have in this case the following format:</p> @@ -886,7 +941,7 @@ DiB == gen_digest(ChA, ICA)? <cell align="center"><c>ControlMessage</c></cell> <cell align="center"><c>Message</c></cell> </row> - <tcaption>Format of Messages Passed between Nodes (before ERTS 5.7.2) + <tcaption>Format of Messages Passed between Nodes (before ERTS 5.7.2 (OTP R13B)) </tcaption> </table> @@ -911,6 +966,7 @@ DiB == gen_digest(ChA, ICA)? </item> </taglist> + <marker id="control_message"/> <p>The <c>ControlMessage</c> is a tuple, where the first element indicates which distributed operation it encodes:</p> @@ -928,6 +984,7 @@ DiB == gen_digest(ChA, ICA)? <tag><c>EXIT</c></tag> <item> <p><c>{3, FromPid, ToPid, Reason}</c></p> + <p>This signal is sent when a link has been broken</p> </item> <tag><c>UNLINK</c></tag> <item> @@ -950,6 +1007,7 @@ DiB == gen_digest(ChA, ICA)? <tag><c>EXIT2</c></tag> <item> <p><c>{8, FromPid, ToPid, Reason}</c></p> + <p>This signal is sent by a call to the erlang:exit/2 bif</p> </item> </taglist> </section> @@ -972,7 +1030,7 @@ DiB == gen_digest(ChA, ICA)? <p><c>{16, FromPid, Unused, ToName, TraceToken}</c></p> <p>Followed by <c>Message</c>.</p> <p><c>Unused</c> is kept for backward compatibility.</p> - </item> + </item> <tag><c>EXIT2_TT</c></tag> <item> <p><c>{18, FromPid, ToPid, TraceToken, Reason}</c></p> @@ -1017,4 +1075,117 @@ DiB == gen_digest(ChA, ICA)? </item> </taglist> </section> + + <section> + <title>New Ctrlmessages for Erlang/OTP 21</title> + <taglist> + <tag><c>SEND_SENDER</c></tag> + <item> + <p><c>{22, FromPid, ToPid}</c></p> + <p>Followed by <c>Message</c>.</p> + <p> + This control message replaces the <c>SEND</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_SEND_SENDER</c></seealso> + has been negotiated in the connection setup handshake. + </p> + <note><p> + Messages encoded before the connection has + been set up may still use the <c>SEND</c> control + message. However, once a <c>SEND_SENDER</c> or <c>SEND_SENDER_TT</c> + control message has been sent, no more <c>SEND</c> + control messages will be sent in the same direction + on the connection. + </p></note> + </item> + <tag><c>SEND_SENDER_TT</c></tag> + <item> + <p><c>{23, FromPid, ToPid, TraceToken}</c></p> + <p>Followed by <c>Message</c>.</p> + <p> + This control message replaces the <c>SEND_TT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_SEND_SENDER</c></seealso> + has been negotiated in the connection setup handshake. + </p> + <note><p> + Messages encoded before the connection has + been set up may still use the <c>SEND_TT</c> control + message. However, once a <c>SEND_SENDER</c> or <c>SEND_SENDER_TT</c> + control message has been sent, no more <c>SEND_TT</c> + control messages will be sent in the same direction + on the connection. + </p></note> + </item> + </taglist> + </section> + + <section> + <title>New Ctrlmessages for Erlang/OTP 22</title> + <note><p> + Messages encoded before the connection has + been set up may still use the non-PAYLOAD variant. + However, once a PAYLOAD control message has been sent, + no more non-PAYLOAD control messages will be sent in + the same direction on the connection. + </p></note> + <taglist> + <tag><c>PAYLOAD_EXIT</c></tag> + <item> + <p><c>{24, FromPid, ToPid}</c></p> + <p>Followed by <c>Reason</c>.</p> + <p> + This control message replaces the <c>EXIT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_EXIT_PAYLOAD</c></seealso> + has been negotiated in the connection setup handshake. + </p> + </item> + <tag><c>PAYLOAD_EXIT_TT</c></tag> + <item> + <p><c>{25, FromPid, ToPid}</c></p> + <p>Followed by <c>Reason</c>.</p> + <p> + This control message replaces the <c>EXIT_TT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_EXIT_PAYLOAD</c></seealso> + has been negotiated in the connection setup handshake. + </p> + </item> + <tag><c>PAYLOAD_EXIT2</c></tag> + <item> + <p><c>{26, FromPid, ToPid}</c></p> + <p>Followed by <c>Reason</c>.</p> + <p> + This control message replaces the <c>EXIT2</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_EXIT_PAYLOAD</c></seealso> + has been negotiated in the connection setup handshake. + </p> + </item> + <tag><c>PAYLOAD_EXIT2_TT</c></tag> + <item> + <p><c>{27, FromPid, ToPid}</c></p> + <p>Followed by <c>Reason</c>.</p> + <p> + This control message replaces the <c>EXIT2_TT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_EXIT_PAYLOAD</c></seealso> + has been negotiated in the connection setup handshake. + </p> + </item> + <tag><c>PAYLOAD_MONITOR_P_EXIT</c></tag> + <item> + <p><c>{28, FromPid, ToPid, Ref}</c></p> + <p>Followed by <c>Reason</c>.</p> + <p> + This control message replaces the <c>MONITOR_P_EXIT</c> control + message and will be sent when the distribution flag + <seealso marker="erl_dist_protocol#dflags"><c>DFLAG_EXIT_PAYLOAD</c></seealso> + has been negotiated in the connection setup handshake. + </p> + </item> + </taglist> + </section> + </chapter> |