vn_bind — Bind a name to a socket

Function

The vn_bind operation associates a name with a socket.

Environment on entry and exit

Input parameter format

vn_bind     (Token_structure,
             OSI_structure,
             Audit_structure,
             Sockaddr_length,
             Sockaddr,
             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 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.

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

A fullword in which the vn_bind 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 completed 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_bind operation stores the return code. The vn_bind operation returns Return_code only if Return_value is -1. See z/OS UNIX System Services Messages and Codes for a complete list of supported return code values.

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

Return_code	Explanation
EAFNOSUPPORT	The address family that was specified is not supported.
EINVAL	The length of the name is either too short or negative.

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

A fullword where the vn_bind operation stores the reason code. The vn_bind 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_bind 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 bind() function.

Specific processing notes

An unbind flag can be passed in the first word of the system data area of the Token_structure, ts_sysdl. A value of 1 in this word indicates that the socket should be reset to an unbound state, if possible. If the socket can be reset to an unbound state, then a subsequent vn_bind call with a different Sockaddr might be successful. If the socket cannot be unbound, the call should be rejected. All other parameters are the same as on a successful vn_bind call. There is no external application interface for this function; it is used internally by the Common INET (CINET) layer so that CINET can try to place an application socket back into a state where another call to bind() may succeed after a bind() has succeeded on some transports but failed on others.

A bind with source address selection flag can be passed in the first word of the system data area of the Token_structure, ts_sysd1. A value of 2 in this word indicates that the socket should be bound using the source address selection preferences. (bind2addrsel())

The function specifies the destination IP address. When this function is used, the socket is bound to the "best" source address for the provided destination IP address.

The caller's suggestion of "best" source address is set by using the setsockopt () call with the IPv6 socket option Sock#IPV6_ADDR_PREFERENCES. Port number is irrelevant for bind2addrsel() function.

The return value, return code, and reason code are same as the bind() operation. The external application interface for this function is the BPX1BAS, BPX4BAS, and bind2addrsel() functions. See these functions in z/OS UNIX System Services Programming: Assembler Callable Services Reference for more details.

Serialization provided by the LFS

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

Security calls to be made by the PFS

When a program specifies a port value less than 1024 decimal, the PFS must call SAF's Check Privilege function to verify that the caller has the authority to do so.