diff options
Diffstat (limited to 'lib/erl_interface/doc')
| -rw-r--r-- | lib/erl_interface/doc/src/ei_connect.xml | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/lib/erl_interface/doc/src/ei_connect.xml b/lib/erl_interface/doc/src/ei_connect.xml index 607a7cbff4..af838e065a 100644 --- a/lib/erl_interface/doc/src/ei_connect.xml +++ b/lib/erl_interface/doc/src/ei_connect.xml @@ -85,6 +85,271 @@ 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><ret>struct hostent</ret><nametext>*ei_gethostbyaddr(const char *addr, int len, int type)</nametext></name> @@ -96,6 +361,7 @@ <p>Convenience functions for some common name lookup functions.</p> </desc> </func> + <func> <name><ret>int</ret><nametext>ei_accept(ei_cnode *ec, int listensock, ErlConnect *conp)</nametext></name> @@ -141,6 +407,14 @@ typedef struct { </func> <func> + <name><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><ret>int</ret><nametext>ei_connect(ei_cnode* ec, char *nodename)</nametext></name> <name><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 +467,9 @@ fd = ei_xconnect(&ec, &addr, ALIVE); <func> <name><ret>int</ret><nametext>ei_connect_init(ei_cnode* ec, const char* this_node_name, const char *cookie, short creation)</nametext></name> + <name><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><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><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 +512,21 @@ 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 +590,45 @@ if (ei_connect_init(&ec, "madonna", "cookie...", n++) < 0) { </func> <func> + <name><ret>int</ret><nametext>ei_listen(ei_cnode *ec, int *port, int backlog)</nametext></name> + <name><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><ret>int</ret><nametext>ei_publish(ei_cnode *ec, int port)</nametext></name> <fsummary>Publish a node name.</fsummary> <desc> |