Function

The vn_connect operation connects to a socket. The socket can be either a stream socket or a datagram socket. The connection is done for stream sockets by a client; a bind and a listen request must have preceded this request at the server.

Environment on entry and exit

See Environment for PFS operations.

Parameters

Token_structure

Supplied parameter

Type:

TOKSTR

Length:

Specified by TOKSTR.ts_hdr.cblen.

The Token_structure represents the file (vnode) that is being operated on. It contains the PFS's initialization token, mount token, and the file token. Refer to LFS/PFS control block structure for a discussion of this structure, and to the TOKSTR typedef in BPXYPFSI in Interface structures for C language servers and clients for its mapping.

OSI_structure

Supplied and returned parameter

Type:

OSI

Length:

Specified by OSI.osi_hdr.cblen.

The OSI_structure contains information that is used by the OSI operations that may be called by the PFS. See OSI services for more information.

It also contains MVS-specific information that needs to be passed to the PFS, including SMF accounting fields, a work area, a recovery area, and an optional pointer to an output ATTR structure. For more details on the OSI structure, see The OSI structure.

This area is mapped by the OSI typedef in BPXYPFSI in Interface structures for C language servers and clients.

Audit_structure

Supplied parameter

Type:

CRED

Length:

Specified by CRED.cred_hdr.cblen.

The Audit_structure contains information that is used by the security product for access checks and auditing. It is passed to most SAF routines that are invoked by the PFS.

Refer to Security responsibilities and considerations for a discussion of security processing, and to the CRED typedef in BPXYPFSI in Interface structures for C language servers and clients for the mapping of this structure.

Sockaddr_length

Supplied parameter

Type:

Integer

Length:

Fullword

A fullword that contains the length of sockaddr.

Sockaddr

Supplied parameter

Type:

SOCK

Length:

Specified by Sockaddr_length

A structure that varies depending on the address family type. It contains the address that is to be used for this operation. For an example of this mapping for AF_INET, see in.h.

Open_flags

Supplied parameter

Type:

Structure

Length:

Fullword

A fullword that contains the bits that are associated with the socket. The defined values for this field are mapped by fcntl.h.

Return_value

Returned parameter

Type:

Integer

Length:

Fullword

A fullword in which the vn_connect operation returns the results of the operation, as one of the following:

Return_value

Meaning

-1

The operation was not successful. The Return_code and Reason_Code values must be filled in by the PFS when Return_value is -1.

0

The operation was successful.

Return_code

Returned parameter

Type:

Integer

Length:

Fullword

A fullword in which the vn_connect operation stores the return code. The vn_connect operation returns Return_code only if Return_value is -1. For a complete list of supported return code values, see z/OS UNIX System Services Messages and Codes.

The vn_connect operation should support at least the following error values:

Return_code	Explanation
ECONNREFUSED	The connection request was rejected.
EINTR	The request was interrupted by a signal.
EINVAL	The length of the name specified was too short, or negative.
EISCONN	The socket is already connected.
ENOAFSUPPORT	The PFS does not support this address family.
EOPNOTSUPP	The socket that was specified is a server; a listen has been done.
EPROTOTYPE	The request is for an incorrect socket type.
EWOULDBLOCK	The operation would have required a blocking wait, and this socket was marked as nonblocking.

Reason_code

Returned parameter

Type:

Integer

Length:

Fullword

A fullword in which the vn_connect operation stores the reason code. The vn_connect operation returns Reason_code only if Return_value is -1. Reason_code further qualifies the Return_code value. These reason codes are documented by the PFS.

Implementation notes

Overview of vn_connect processing

For more information about the semantics of this operation for a POSIX-conforming PFS, refer to the publications that are mentioned in Finding more information about sockets for the connect function.

Specific processing notes

The connect() function performs a different action for each of the following types of initiating sockets:

• If the initiating socket is SOCK_DGRAM, the connect() function establishes the peer address. The peer address identifies the socket to which all datagrams are sent on subsequent send() functions. No connections are made by this connect() function.
• If the initiating socket is SOCK_STREAM, the connect() function attempts to make a connection to the socket that is specified by the Sockaddr parameter.

Serialization provided by the LFS

The vn_connect operation is invoked with an exclusive latch held on the vnode of the socket.

Security calls to be made by the PFS

None.

Related services

• vn_listen — Listen on a socket
• vn_accept — Accept a socket connection request
• vn_bind — Bind a name to a socket