vn_setpeer — Set a socket's peer address

Function

The vn_setpeer operation presets the peer address that is associated with a socket. This causes all datagrams that are sent using the specified socket to be sent to the address that is specified here. Only datagrams that are sent from the specified address are received.

Environment on entry and exit

See Environment for PFS operations.

Input parameter format

vn_setpeer  (Token_structure,
             OSI_structure,
             Audit_structure,
             Sockaddr_length,
             Sockaddr,
             Option,
             Return_value,
             Return_code,
             Reason_code)

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 and returned parameter

Type:: Integer
Length:: Fullword

A fullword that supplies the length of the Sockaddr buffer and returns the length of the Sockaddr structure that is returned.

Sockaddr

Supplied and returned parameter

Type:: Structure
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.

Option

Supplied parameter

Type:: Integer
Length:: Fullword

A fullword that specifies the option of the vn_setpeer operation to use. These values are mapped by socket.h.

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_setpeer 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_setpeer operation stores the return code. The vn_setpeer 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_setpeer operation should support at least the following error value:

Return_code	Explanation
EINVAL	The address length that was specified is not the size of a valid address for the specified address family.

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_setpeer operation stores the reason code. The vn_setpeer 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_setpeer processing

The vn_setpeer call is new for POSIX 1003.12, and is not currently supported by any of the socket PFSs.

Specific processing notes

Calling setpeer() with the option set to SO_SET causes all datagrams that are sent through this socket to be sent to the address that is specified by sockaddr. Only datagrams that originate from sockaddr are received.
Calling setpeer() with the option set to SO_SET on the passive end of a virtual circuit before calling listen() or connect() causes an error. Calling connect() and specifying a destination address with setpeer causes an error. Calling setpeer() after a connection is established is an error.
The result of calling setpeer() with the option set to SO_SET on an endpoint that has already had the destination address preset causes an error if the underlying protocol does not support multiple peer addresses for a given endpoint.

Serialization provided by the LFS

The vn_setpeer 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

None.