CONNECT

The CONNECT macro is used by a client to establish a connection between a local socket and a remote socket.

For stream sockets, the CONNECT macro:

Completes the binding process for a stream socket if BIND has not been previously issued.
Attempts connection to a remote socket. This connection must be completed before data can be transferred.

For datagram sockets, CONNECT is not essential, but you can use it to send messages without specifying the destination.

For both types of sockets, the following CONNECT macro sequence applies:

The server issues BIND and LISTEN (stream sockets only) to create a passive open socket.
The client issues CONNECT to request a connection.
The server creates a new connected socket by accepting the connection on the passive open socket.

If the socket is in blocking mode, CONNECT blocks the calling program until the connection is established or until an error is received.

If the socket is in nonblocking mode, the return code indicates the success of the connection request.

A 0 RETCODE indicates that the connection was completed.
A nonzero RETCODE with an ERRNO of 36 (EINPROGRESS) indicates that the connection could not be completed, but since the socket is nonblocking, the CONNECT macro completes its processing.

The caller must test the completion of the connection setup by calling SELECT and testing for the ability to write to the socket. The completion cannot be checked by issuing a second CONNECT.

The following requirements apply to this call:

Authorization:

Supervisor state or problem state, any PSW key.

Dispatchable unit mode:

Task.

Cross memory mode:

PASN = HASN.

Amode:

31-bit or 24-bit.

Note: See "Addressability mode (Amode) considerations" under CALL instruction API environmental restrictions and programming requirements.

ASC mode:

Primary address space control (ASC) mode.

Interrupt status:

Enabled for interrupts.

Locks:

Unlocked.

Control parameters:

All parameters must be addressable by the caller and in the primary address space.


>>-EZASMI--TYPE=CONNECT--,S--=--+-number---+-------------------->
                                +-address--+   
                                +-*indaddr-+   
                                '-(reg)----'   

>--,NAME--=--+-address--+--,ERRNO--=--+-address--+-------------->
             +-*indaddr-+             +-*indaddr-+   
             '-(reg)----'             '-(reg)----'   

>--,RETCODE--=--+-address--+--+---------------------------+----->
                +-*indaddr-+  +-,ECB--=--+-address--+-----+   
                '-(reg)----'  |          +-*indaddr-+     |   
                              |          '-(reg)----'     |   
                              '-,REQAREA--=--+-address--+-'   
                                             +-*indaddr-+     
                                             '-(reg)----'     

>--+-------------------------+--+------------------------+-----><
   '-,ERROR--=--+-address--+-'  '-,TASK--=--+-address--+-'   
                +-*indaddr-+                +-*indaddr-+     
                '-(reg)----'                '-(reg)----'

Keyword

Description

S

Input parameter. A value or the address of a halfword binary number specifying the socket descriptor.

NAME

Input parameter. The NAME parameter for CONNECT specifies the IPv4 or IPv6 socket address of the IPv4 or IPv6 IP connection peer. Include the SYS1.MACLIB(BPXYSOCK) macro to get the assembler mappings for the socket address structure. The socket address structure mappings begin at the SOCKADDR label. The AF_INET socket address structure fields start at the SOCK_SIN label. The AF_INET6 socket address structure fields start at the SOCK_SIN6 label.

The IPv4 socket structure must specify the following fields:

Field: Description
FAMILY: A halfword binary field specifying the IPv4 addressing family. For IPv4 the value is always a decimal 2, indicating AF_INET.
PORT: A halfword binary field that is set to the server port number in network byte order. For example, if the port number is 5000 in decimal, it is set to X'1388'.
IPv4-ADDRESS: A fullword binary field specifying the 32-bit IPv4 Internet Protocol address, in network byte order, of the server host machine. For example, if the Internet Protocol address is 129.4.5.12 in dotted decimal notation, it is set to X'8104050C'.
RESERVED: Specifies 8 bytes of binary zeros. This field is required, but not used.

The IPv6 socket structure must specify the following fields:

Field: Description
NAMELEN: A 1-byte binary field specifying the length of this IPv6 socket address structure. Any value specified by the use of this field is ignored when processed as input and the field is set to 0 when processed as output.
FAMILY: A 1-byte binary field specifying the IPv6 addressing family. For IPv6 the value is a decimal 19, indicating AF_INET6.
PORT: A halfword binary field that is set to the port number in network byte order. For example, if the port number is 5000 in decimal, it is set to X'1388'.
FLOW-INFO: A fullword binary field specifying the traffic class and flow label. This field must be set to 0.
IPv6-ADDRESS: A 16-byte binary field that is set to the 128-bit IPv6 Internet Protocol address, in network byte order, of the client host machine. For example, if the IPv6 Internet Protocol address is 12ab:0:0:cd30:123:4567:89AB:cedf in colon-hexadecimal notation, it is set to X'12AB00000000CD300123456789ABCDEF'.
SCOPE-ID: A fullword binary field which identifies a set of interfaces as appropriate for the scope of the address carried in the IPv6-ADDRESS field. A value of 0 indicates the SCOPE-ID field does not identify the set of interfaces to be used, and can be specified for any address types and scopes. For a link scope IPv6-ADDRESS, SCOPE-ID can specify a link index which identifies a set of interfaces. For all other address scopes, SCOPE-ID must be set to 0.

ERRNO

Output parameter. A fullword binary field. If RETCODE is negative, ERRNO contains a valid error number. Otherwise, ignore ERRNO.

See Socket call error return codes for information about ERRNO return codes.

RETCODE

Output parameter. A fullword binary field that returns one of the following values:

Value: Description
0: Successful call.
-1: Check ERRNO for an error code.

ECB or REQAREA

Input parameter. This parameter is required if you are using APITYPE=3. It points to a 104-byte field containing:

For ECB: A 4-byte ECB posted by TCP/IP when the macro completes.
For REQAREA: A 4-byte user token (set by you) that is presented to your exit when the response to this function request is complete.
For ECB/REQAREA: The last 100 bytes is a storage field used by the interface to save the state information.

Note: This storage must not be modified until the macro function has completed and the ECB has been posted, or the asynchronous exit has been driven.

ERROR

Input parameter. The location in your program to receive control when the application programming interface (API) processing module cannot be loaded.

TASK

Input parameter. The location of the task storage area in your program.