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authorRickard Green <[email protected]>2019-01-23 15:57:03 +0100
committerRickard Green <[email protected]>2019-01-23 15:57:03 +0100
commita4641c5b3469d2e3cb9b0937ed941748fbbf2036 (patch)
tree66791aea3fda66e16a5041d1c6a37726e5880bba /lib/erl_interface/doc
parenta8364425a7190b65cd33e58ac3c155a77c462b74 (diff)
parenteaeec753c035c2214be2930290a0a6de411566b0 (diff)
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Merge branch 'rickard/ei-ext/OTP-15442' into rickard/ei-ext-maint/OTP-15442
Diffstat (limited to 'lib/erl_interface/doc')
-rw-r--r--lib/erl_interface/doc/src/ei_connect.xml332
1 files changed, 332 insertions, 0 deletions
diff --git a/lib/erl_interface/doc/src/ei_connect.xml b/lib/erl_interface/doc/src/ei_connect.xml
index 6f16c0652e..e318dd6664 100644
--- a/lib/erl_interface/doc/src/ei_connect.xml
+++ b/lib/erl_interface/doc/src/ei_connect.xml
@@ -85,6 +85,273 @@
the <c>_tmo</c> suffix.</p>
</section>
+ <section>
+ <marker id="ussi"/>
+ <title>User Supplied Socket Implementation</title>
+ <p>By default <c>ei</c> supplies a TCP/IPv4 socket interface
+ that is used when communicating. The user can however plug in
+ his/her own IPv4 socket implementation. This, for example, in order
+ to communicate over TLS. A user supplied socket implementation
+ is plugged in by passing a
+ <seealso marker="#ei_socket_callbacks">callback structure</seealso>
+ to either
+ <seealso marker="#ei_connect_init"><c>ei_connect_init_ussi()</c></seealso>
+ or
+ <seealso marker="#ei_connect_init"><c>ei_connect_xinit_ussi()</c></seealso>.</p>
+
+ <p>All callbacks in the <c>ei_socket_callbacks</c> structure
+ <em>should</em> return zero on success; and a posix error
+ code on failure.</p>
+
+ <p>The <c>addr</c> argument of the <c>listen</c>, <c>accept</c>,
+ and <c>connect</c> callbacks refer to appropriate address
+ structure for currently used protocol. Currently <c>ei</c>
+ only supports IPv4. That is, at this time <c>addr</c> always
+ points to a <c>struct sockaddr_in</c> structure.</p>
+
+ <p>The <c>ei_socket_callbacks</c> structure may be enlarged in
+ the future. All fields not set, <em>needs</em> to be zeroed out.</p>
+
+ <marker id="ei_socket_callbacks"/>
+ <code type="none"><![CDATA[
+typedef struct {
+ int flags;
+ int (*socket)(void **ctx, void *setup_ctx);
+ int (*close)(void *ctx);
+ int (*listen)(void *ctx, void *addr, int *len, int backlog);
+ int (*accept)(void **ctx, void *addr, int *len, unsigned tmo);
+ int (*connect)(void *ctx, void *addr, int len, unsigned tmo);
+ int (*writev)(void *ctx, const void *iov, int iovcnt, ssize_t *len, unsigned tmo);
+ int (*write)(void *ctx, const char *buf, ssize_t *len, unsigned tmo);
+ int (*read)(void *ctx, char *buf, ssize_t *len, unsigned tmo);
+ int (*handshake_packet_header_size)(void *ctx, int *sz);
+ int (*connect_handshake_complete)(void *ctx);
+ int (*accept_handshake_complete)(void *ctx);
+ int (*get_fd)(void *ctx, int *fd);
+} ei_socket_callbacks;
+ ]]></code>
+
+ <taglist>
+
+ <tag><c>flags</c></tag>
+ <item>
+ <p>Flags informing <c>ei</c> about the behaviour of the
+ callbacks. Flags should be bitwise or:ed together. If no flag,
+ is set, the <c>flags</c> field should contain <c>0</c>. Currently,
+ supported flags:</p>
+ <taglist>
+ <tag><c>EI_SCLBK_FLG_FULL_IMPL</c></tag>
+ <item>
+ <p>
+ If set, the <c>accept()</c>, <c>connect()</c>,
+ <c>writev()</c>, <c>write()</c>, and <c>read()</c> callbacks
+ implements timeouts. The timeout is passed in the <c>tmo</c>
+ argument and is given in milli seconds. Note that the
+ <c>tmo</c> argument to these callbacks differ from the
+ timeout arguments in the <c>ei</c> API. Zero means a zero
+ timeout. That is, poll and timeout immediately unless the
+ operation is successful. <c>EI_SCLBK_INF_TMO</c>
+ (max <c>unsigned</c>) means infinite timeout. The file
+ descriptor is in blocking mode when a callback is called,
+ and it must be in blocking mode when the callback returns.
+ </p>
+ <p>
+ If not set, <c>ei</c> will implement the timeout using
+ <c>select()</c> in order to determine when to call the
+ callbacks and when to time out. The <c>tmo</c> arguments
+ of the <c>accept()</c>, <c>connect()</c>, <c>writev()</c>,
+ <c>write()</c>, and <c>read()</c> callbacks should be
+ ignored. The callbacks may be called in non-blocking mode.
+ The callbacks are not allowed to change between blocking
+ and non-blocking mode. In order for this to work,
+ <c>select()</c> needs to interact with the socket primitives
+ used the same way as it interacts with the ordinary socket
+ primitives. If this is not the case, the callbacks
+ <em>need</em> to implement timeouts and this flag should
+ be set.
+ </p>
+ </item>
+ </taglist>
+ <p>More flags may be introduced in the future.</p>
+ </item>
+
+ <tag><c>int (*socket)(void **ctx, void *setup_ctx)</c></tag>
+ <item>
+ <p>Create a socket and a context for the socket.</p>
+
+ <p>On success it should set <c>*ctx</c> to point to a context for
+ the created socket. This context will be passed to all other
+ socket callbacks. This function will be passed the same
+ <c>setup_context</c> as passed to the preceeding
+ <seealso marker="#ei_connect_init"><c>ei_connect_init_ussi()</c></seealso>
+ or
+ <seealso marker="#ei_connect_init"><c>ei_connect_xinit_ussi()</c></seealso>
+ call.</p>
+
+ <note><p>During the lifetime of a socket, the pointer <c>*ctx</c>
+ <em>has</em> to remain the same. That is, it cannot later be
+ relocated.</p></note>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*close)(void *ctx)</c></tag>
+ <item>
+ <p>Close the socket identified by <c>ctx</c> and destroy the context.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*listen)(void *ctx, void *addr, int *len, int backlog)</c></tag>
+ <item>
+ <p>Bind the socket identified by <c>ctx</c> to a local interface
+ and then listen on it.</p>
+
+ <p>The <c>addr</c> and <c>len</c> arguments are both input and output
+ arguments. When called <c>addr</c> points to an address structure of
+ lenght <c>*len</c> containing information on how to bind the socket.
+ Uppon return this callback should have updated the structure referred
+ by <c>addr</c> with information on how the socket actually was bound.
+ <c>*len</c> should be updated to reflect the size of <c>*addr</c>
+ updated. <c>backlog</c> identifies the size of the backlog for the
+ listen socket.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*accept)(void **ctx, void *addr, int *len, unsigned tmo)</c></tag>
+ <item>
+ <p>Accept connections on the listen socket identified by
+ <c>*ctx</c>.</p>
+
+ <p>When a connection is accepted, a new context for the accepted
+ connection should be created and <c>*ctx</c> should be updated
+ to point to the new context for the accepted connection. When
+ called <c>addr</c> points to an uninitialized address structure
+ of lenght <c>*len</c>. Uppon return this callback should have
+ updated this structure with information about the client address.
+ <c>*len</c> should be updated to reflect the size of <c>*addr</c>
+ updated.
+ </p>
+
+ <p>If the <c>EI_SCLBK_FLG_FULL_IMPL</c> flag has been set,
+ <c>tmo</c> contains timeout time in milliseconds.</p>
+
+ <note><p>During the lifetime of a socket, the pointer <c>*ctx</c>
+ <em>has</em> to remain the same. That is, it cannot later be
+ relocated.</p></note>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*connect)(void *ctx, void *addr, int len, unsigned tmo)</c></tag>
+ <item>
+ <p>Connect the socket identified by <c>ctx</c> to the address
+ identified by <c>addr</c>.</p>
+
+ <p>When called <c>addr</c> points to an address structure of
+ lenght <c>len</c> containing information on where to connect.</p>
+
+ <p>If the <c>EI_SCLBK_FLG_FULL_IMPL</c> flag has been set,
+ <c>tmo</c> contains timeout time in milliseconds.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*writev)(void *ctx, const void *iov, long iovcnt, ssize_t *len, unsigned tmo)</c></tag>
+ <item>
+ <p>Write data on the connected socket identified by <c>ctx</c>.</p>
+
+ <p><c>iov</c> points to an array of <c>struct iovec</c> structures of
+ length <c>iovcnt</c> containing data to write to the socket. On success,
+ this callback should set <c>*len</c> to the amount of bytes successfully
+ written on the socket.</p>
+
+ <p>If the <c>EI_SCLBK_FLG_FULL_IMPL</c> flag has been set,
+ <c>tmo</c> contains timeout time in milliseconds.</p>
+
+ <p>This callback is optional. Set the <c>writev</c> field
+ in the the <c>ei_socket_callbacks</c> structure to <c>NULL</c> if not
+ implemented.</p>
+ </item>
+
+ <tag><c>int (*write)(void *ctx, const char *buf, ssize_t *len, unsigned tmo)</c></tag>
+ <item>
+ <p>Write data on the connected socket identified by <c>ctx</c>.</p>
+
+ <p>When called <c>buf</c> points to a buffer of length <c>*len</c>
+ containing the data to write on the socket. On success, this callback
+ should set <c>*len</c> to the amount of bytes successfully written on
+ the socket.</p>
+
+ <p>If the <c>EI_SCLBK_FLG_FULL_IMPL</c> flag has been set,
+ <c>tmo</c> contains timeout time in milliseconds.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*read)(void *ctx, char *buf, ssize_t *len, unsigned tmo)</c></tag>
+ <item>
+ <p>Read data on the connected socket identified by <c>ctx</c>.</p>
+
+ <p><c>buf</c> points to a buffer of length <c>*len</c> where the
+ read data should be placed. On success, this callback should update
+ <c>*len</c> to the amount of bytes successfully read on the socket.</p>
+
+ <p>If the <c>EI_SCLBK_FLG_FULL_IMPL</c> flag has been set,
+ <c>tmo</c> contains timeout time in milliseconds.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*handshake_packet_header_size)(void *ctx, int *sz)</c></tag>
+ <item>
+ <p>Inform about handshake packet header size to use during the Erlang
+ distribution handshake.</p>
+
+ <p>On success, <c>*sz</c> should be set to the handshake packet header
+ size to use. Valid values are <c>2</c> and <c>4</c>. Erlang TCP
+ distribution use a handshake packet size of <c>2</c> and Erlang TLS
+ distribution use a handshake packet size of <c>4</c>.</p>
+
+ <p>This callback is mandatory.</p>
+ </item>
+
+ <tag><c>int (*connect_handshake_complete)(void *ctx)</c></tag>
+ <item>
+ <p>Called when a locally started handshake has completed successfully.</p>
+
+ <p>This callback is optional. Set the <c>connect_handshake_complete</c> field
+ in the <c>ei_socket_callbacks</c> structure to <c>NULL</c> if not implemented.</p>
+ </item>
+
+ <tag><c>int (*accept_handshake_complete)(void *ctx)</c></tag>
+ <item>
+ <p>Called when a remotely started handshake has completed successfully.</p>
+
+ <p>This callback is optional. Set the <c>accept_handshake_complete</c> field in
+ the <c>ei_socket_callbacks</c> structure to <c>NULL</c> if not implemented.</p>
+ </item>
+
+ <tag><c>int (*get_fd)(void *ctx, int *fd)</c></tag>
+ <item>
+ <p>Inform about file descriptor used by the socket which is identified
+ by <c>ctx</c>.</p>
+
+ <note><p>During the lifetime of a socket, the file descriptor
+ <em>has</em> to remain the same. That is, repeated calls to this
+ callback with the same context <c>should</c> always report the same
+ file descriptor.</p>
+ <p>The file descriptor <em>has</em> to be a real file descriptor.
+ That is, no other operation should be able to get the same file
+ descriptor until it has been released by the <c>close()</c>
+ callback.</p>
+ </note>
+
+ <p>This callback is mandatory.</p>
+ </item>
+ </taglist>
+ </section>
<funcs>
<func>
<name since=""><ret>struct hostent *</ret><nametext>ei_gethostbyaddr(const char *addr, int len, int type)</nametext></name>
@@ -96,6 +363,7 @@
<p>Convenience functions for some common name lookup functions.</p>
</desc>
</func>
+
<func>
<name since=""><ret>int</ret><nametext>ei_accept(ei_cnode *ec, int listensock, ErlConnect *conp)</nametext></name>
@@ -141,6 +409,14 @@ typedef struct {
</func>
<func>
+ <name since="OTP @OTP-15442@"><ret>int</ret><nametext>ei_close_connection(int fd)</nametext></name>
+ <fsummary>Close a connection.</fsummary>
+ <desc>
+ <p>Closes a previously opened connection or listen socket.</p>
+ </desc>
+ </func>
+
+ <func>
<name since=""><ret>int</ret><nametext>ei_connect(ei_cnode* ec, char *nodename)</nametext></name>
<name since=""><ret>int</ret><nametext>ei_xconnect(ei_cnode* ec, Erl_IpAddr adr, char *alivename)</nametext></name>
<fsummary>Establish a connection to an Erlang node.</fsummary>
@@ -193,7 +469,9 @@ fd = ei_xconnect(&ec, &addr, ALIVE);
<func>
<name since=""><ret>int</ret><nametext>ei_connect_init(ei_cnode* ec, const char* this_node_name, const char *cookie, short creation)</nametext></name>
+ <name since="OTP @OTP-15442@"><ret>int</ret><nametext>ei_connect_init_ussi(ei_cnode* ec, const char* this_node_name, const char *cookie, short creation, ei_socket_callbacks *cbs, int cbs_sz, void *setup_context)</nametext></name>
<name since=""><ret>int</ret><nametext>ei_connect_xinit(ei_cnode* ec, const char *thishostname, const char *thisalivename, const char *thisnodename, Erl_IpAddr thisipaddr, const char *cookie, short creation)</nametext></name>
+ <name since="OTP @OTP-15442@"><ret>int</ret><nametext>ei_connect_xinit_ussi(ei_cnode* ec, const char *thishostname, const char *thisalivename, const char *thisnodename, Erl_IpAddr thisipaddr, const char *cookie, short creation, ei_socket_callbacks *cbs, int cbs_sz, void *setup_context)</nametext></name>
<fsummary>Initialize for a connection.</fsummary>
<desc>
<p>Initializes the <c>ec</c> structure, to
@@ -236,6 +514,21 @@ fd = ei_xconnect(&ec, &addr, ALIVE);
<item>
<p><c>thispaddr</c> if the IP address of the host.</p>
</item>
+ <item>
+ <p><c>cbs</c> is a pointer to a
+ <seealso marker="#ei_socket_callbacks">callback structure</seealso>
+ implementing and alternative socket interface.</p>
+ </item>
+ <item>
+ <p><c>cbs_sz</c> is the size of the structure
+ pointed to by <c>cbs</c>.</p>
+ </item>
+ <item>
+ <p><c>setup_context</c> is a pointer to a structure that
+ will be passed as second argument to the <c>socket</c> callback
+ in the <c>cbs</c> structure.</p>
+ </item>
+
</list>
<p>A C-node acting as a server is assigned a creation
number when it calls <c>ei_publish()</c>.</p>
@@ -299,6 +592,45 @@ if (ei_connect_init(&ec, "madonna", "cookie...", n++) < 0) {
</func>
<func>
+ <name since="OTP @OTP-15442@"><ret>int</ret><nametext>ei_listen(ei_cnode *ec, int *port, int backlog)</nametext></name>
+ <name since="OTP @OTP-15442@"><ret>int</ret><nametext>ei_xlisten(ei_cnode *ec, Erl_IpAddr adr, int *port, int backlog)</nametext></name>
+ <fsummary>Create a listen socket.</fsummary>
+ <desc>
+ <p>Used by a server process to setup a listen socket which
+ later can be used for accepting connections from client processes.
+ </p>
+ <list type="bulleted">
+ <item>
+ <p><c>ec</c> is the C-node structure.</p>
+ </item>
+ <item>
+ <p><c>adr</c> is local interface to bind to.</p>
+ </item>
+ <item>
+ <p><c>port</c> is a pointer to an integer containing the
+ port number to bind to. If <c>*port</c> equals <c>0</c>
+ when calling <c>ei_listen()</c>, the socket will be bound to
+ an ephemeral port. On success, <c>ei_listen()</c> will update
+ the value of <c>*port</c> to the port actually bound to.
+ </p>
+ </item>
+ <item>
+ <p><c>backlog</c> is maximum backlog of pending connections.</p>
+ </item>
+ </list>
+ <p><c>ei_listen</c> will create a socket, bind to a port on the
+ local interface identified by <c>adr</c> (or all local interfaces if
+ <c>ei_listen()</c> is called), and mark the socket as a passive socket
+ (that is, a socket that will be used for accepting incoming connections).
+ </p>
+ <p>
+ On success, a file descriptor is returned which can be used in a call to
+ <c>ei_accept()</c>. On failure, <c>ERL_ERROR</c> is returned and
+ <c>erl_errno</c> is set to <c>EIO</c>.</p>
+ </desc>
+ </func>
+
+ <func>
<name since=""><ret>int</ret><nametext>ei_publish(ei_cnode *ec, int port)</nametext></name>
<fsummary>Publish a node name.</fsummary>
<desc>