System services routines let you write network applications. The
$QIO system service uses network pseudodevice and TELNET port
driver I/O function codes.
1 – $ASSIGN
Provides a calling process with an I/O channel, thereby allowing
the calling process to perform I/O operations on the network
pseudodevice.
On Alpha and I64 systems, this service accepts 64-bit addresses.
Format
SYS$ASSIGN devnam, chan, [acmode], [mbxnam], [flags]
C Prototype
int sys$assign (void *devnam, unsigned short int *chan,
unsigned int acmode, void *mbxnam,...);
Returns
OpenVMS usage:cond_value
type: longword (unsigned)
access: write only
mechanism: by value
Longword condition value. All system services return (by
immediate value) a condition value in R0. Condition values that
can be returned by this service are listed under Condition Values
Returned.
1.1 – Arguments
devnam
OpenVMS usage:device_name
type: character-coded text string
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit
descriptor-fixed-length string descriptor
(VAX) by 32-bit descriptor-fixed-length string
descriptor
Name of the device to which $ASSIGN is to assign a channel. The
devnam argument is the address of a character string descriptor
pointing to the network pseudodevice name string (either
TCPIP$DEVICE: or SYS$NET:).
chan
OpenVMS usage:channel
type: word (unsigned)
access: write only
mechanism: (Alpha and I64) by 32- or 64-bit reference
(VAX) by 32-bit reference
Number of the channel that is assigned. The chan argument is the
address of a word into which $ASSIGN writes the channel number.
acmode
OpenVMS usage:access_mode
type: longword (unsigned)
access: read only
mechanism: by value
Access mode to be associated with the channel. I/O operations on
the channel can be performed only from equal or more privileged
access modes. The $PSLDEF macro defines the following symbols for
the four access modes:
Access
Symbol Mode Numeric Value
PSL$C_KERNEL Kernel 0
PSL$C_EXEC Executive 1
PSL$C_SUPER Supervisor 2
PSL$C_USER User 3
mbxnam
OpenVMS usage:device_name
type: character-coded text string
access: read only
mechanism: (Alpha and I64) by 32-bit or 64-bit
descriptor-fixed-length string descriptor
(VAX) by 32-bit descriptor-fixed-length string
descriptor
This argument is not used.
flags
OpenVMS usage:mask_longword
type: longword (unsigned)
access: read only
mechanism: by value
An optional device-specific argument. The flags argument is a
longword bit mask. For more information about the applicability
of the flags argument for a particular device, refer to the
OpenVMS I/O User's Reference Manual.
1.2 – Description
The $ASSIGN system service establishes a path to a device but
does not check whether the calling process has the capability
to do I/O operations to the device. The device drivers may apply
privilege and protection restrictions. The calling process must
have NETMBX privilege to assign a channel.
System dynamic memory is required for the target device, and the
I/O byte limit quota from the process buffer is used.
When a channel is assigned to the TCPIP$DEVICE: network
pseudodevice, the network software creates a new device called
BGn, where n is a unique unit number. The corresponding channel
number is used in any subsequent operation requests for that
device.
When the auxiliary server creates a process for a service with
the LISTEN flag set, the server creates a device socket. In
order for your application to receive the device socket, assign
a channel to SYS$NET, which is the logical name of a network
pseudodevice, and perform an appropriate $QIO(IO$_SETMODE)
operation.
Channels remain assigned either until they are explicitly
deassigned with the Deassign I/O Channel ($DASSGN) service or,
if they are user-mode channels, until the image that assigned the
channel exits.
1.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ACCVIO The caller cannot read the device string or
string descriptor, or the caller cannot write
the channel number.
SS$_DEVALLOC The device is allocated to another process.
SS$_DEVLSTFULL The system maximum number of BG: device units
has been reached.
SS$_EXQUOTA The process has exceeded its buffered I/O byte
limit (BIOLM) quota.
SS$_IVDEVNAM No device name was specified, the logical name
translation failed, or the device name string
contains invalid characters.
SS$_IVLOGNAM The device name string has a length of zero or
has more than 63 characters.
SS$_NOIOCHAN No I/O channel is available for assignment.
SS$_NOPRIV The specified channel is not assigned or was
assigned from a more privileged access mode.
SS$_NOSUCHDEV The specified device does not exist.
2 – $CANCEL
Cancels all pending I/O requests on a specified channel.
Related Functions
The equivalent Sockets API function is close().
Format
SYS$CANCEL chan
C Prototype
int sys$cancel (unsigned short int chan);
Returns
OpenVMS usage:cond_value
type: longword (unsigned)
access: write only
mechanism: by value
Longword condition value. All system services return (by
immediate value) a condition value in R0. Condition values that
can be returned by this service are listed under Condition Values
Returned.
2.1 – Arguments
chan
OpenVMS usage:channel
type: word (unsigned)
access: read only
mechanism: by value
I/O channel on which I/O is to be canceled. The chan argument is
a word containing the channel number.
2.2 – Description
To cancel I/O on a channel, the access mode of the calling
process must be equal to or more privileged than the access mode
of the process that made the original channel assignment.
The $CANCEL service requires system dynamic memory and uses the
process's buffered I/O limit (BIOLM) quota.
When a request currently in progress is canceled, the driver is
notified immediately. Actual cancellation may or may not occur
immediately, depending on the logical state of the driver. When
cancellation does occur, the action taken for I/O in progress is
similar to that taken for queued requests. For example:
o The specified event flag is set.
o The first word of the I/O status block, if specified, is set
to SS$_CANCEL if the I/O request is queued, or to SS$_ABORT if
the I/O operation is in progress.
o If the asynchronous system trap (AST) is specified, it is
queued.
For proper synchronization between this service and the actual
canceling of I/O requests to take place, the issuing process
must wait for the I/O process to complete normally. Note that
the I/O has been canceled. Outstanding I/O requests are canceled
automatically at image exit.
2.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ABORT A physical line went down during a network
connect operation.
SS$_CANCEL The I/O operation was canceled by executing a
$CANCEL system service.
SS$_EXQUOTA The process has exceeded its buffered I/O
limit (BIOLM) quota.
SS$_INSFMEM Insufficient system dynamic memory to cancel
the I/O.
SS$_IVCHAN An invalid channel was specified (that is, a
channel number of 0 or a number larger than
the number of channels available).
SS$_NOPRIV The specified channel is not assigned or was
assigned from a more privileged access mode.
3 – $DASSGN
Deassigns (releases) an I/O channel previously acquired using the
Assign I/O Channel ($ASSIGN) service.
Related Functions
The equivalent Sockets API function is close().
Format
SYS$DASSGN chan
C Prototype
int sys$dassgn (unsigned short int chan);
Returns
OpenVMS usage:cond_value
type: longword (unsigned)
access: write only
mechanism: by value
Longword condition value. All system services return (by
immediate value) a condition value in R0. Condition values that
can be returned by this service are listed under Condition Values
Returned.
3.1 – Arguments
chan
OpenVMS usage:channel
type: word (unsigned)
access: read only
mechanism: by value
Number of the I/O channel to be deassigned. The chan argument is
a word containing this number.
3.2 – Description
After all communication is completed, use the $DASSGN system
service to free an I/O channel. A $DASSGN operation executed
on a channel associated with a network pseudodevice does the
following:
o Ends all pending operations to send or receive data at $QIO
level ($CANCEL system service).
o Clears the port associated with the channel. When executing
the $DASSGN system service for TCP sockets, the socket remains
until the connection is closed on both the local and remote
sides.
o Ends all communications with the network pseudodevice that the
I/O channel identifies.
o Frees the channel associated with the network pseudodevice. An
I/O channel can be deassigned only from an access mode equal
to or more privileged than the access mode from which the
original channel assignment was made.
I/O channels assigned from user mode are automatically deassigned
at image exit.
NOTE
Even after a $DASSGN has been issued, a TCP socket may
remain until the TCP close timeout interval expires. The
default and maximum timeout interval is either 10 minutes
if the peer host is not responding or 30 seconds after
acknowledging the socket close. Although the TCP socket
is open, you cannot make a reference to that socket after
issuing a $DASSGN.
3.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_IVCHAN An invalid channel number was specified (that
is, a channel number of zero or a number
larger than the number of channels available).
SS$_NOPRIV The specified channel is not assigned or is
assigned from a more privileged access mode.
4 – $QIO
Queues an I/O request to a channel associated with a network
pseudodevice.
The $QIO service is completed asynchronously; that is, it returns
to the caller immediately after queuing the I/O request, without
waiting for the I/O operation to be completed.
For synchronous completion, use the Queue I/O Request and Wait
($QIOW) service. The $QIOW service is identical to the $QIO
service, except the $QIOW returns to the caller after the I/O
operation has completed.
On Alpha and I64 systems, this service accepts 64-bit addresses.
Format
SYS$QIO [efn],chan,func, [iosb],[astadr],[astprm],
[p1],[p2],[p3],[p4], [p5],[p6]
C Prototype
int sys$qio (unsigned int efn, unsigned short int chan,
unsigned int func, struct _iosb *iosb, void
(*astadr)(__unknown_params), __int64 astprm, void
*p1, __int64 p2, __int64 p3, __int64 p4, __int64
p5, __int64 p6);
Returns
OpenVMS usage:cond_value
type: longword (unsigned)
access: write only
mechanism: by value
Longword condition value. All system services return (by
immediate value) a condition value in R0. Condition values that
can be returned by this service are listed under Condition Values
Returned.
4.1 – Arguments
efn
OpenVMS usage:ef_number
type: longword (unsigned)
access: read only
mechanism: by value
Event flag that $QIO sets when the I/O operation completes. The
efn argument is a longword value containing the number of the
event flag; however, $QIO uses only the low-order byte.
If efn is not specified, event flag 0 is set.
The specified event flag is set if the service terminates without
queuing an I/O request.
chan
OpenVMS usage:channel
type: word (unsigned)
access: read only
mechanism: by value
I/O channel that is assigned to the device to which the request
is directed. The chan argument is a word value containing the
number of the I/O channel.
func
OpenVMS usage:function_code
type: longword (unsigned)
access: read only
mechanism: by value
Function codes and function modifiers specifying the operation
to be performed. The func argument is a longword containing the
function code.
For information about the network pseudodevice and TELNET device
function codes and modifiers, see Network Pseudodevice Driver
Functions and TELNET Port Driver I/O Function Codes.
iosb
OpenVMS usage:io_status_block
type: quadword (unsigned)
access: write only
mechanism: (Alpha and I64) by 32-bit reference or 64-bit
reference
(VAX) by 32-bit reference
I/O status block to receive the final completion status of the
I/O operation. The iosb is the address of the quadword I/O status
block.
When the $QIO begins executing, it clears the event flag. The
$QIO also clears the quadword I/O status block if the iosb
argument is specified.
Although the iosb argument is optional, HP strongly recommends
that you specify it, for the following reasons:
o If you are using an event flag to signal the completion of
the service, you can test the I/O status block for a condition
value to be sure that the event flag was not set by an event
other than service completion.
o If you are using the $SYNCH service to synchronize completion
of the service, the I/O status block is a required argument
for $SYNCH.
o The condition value returned in R0 and the condition value
returned in the I/O status block provide information about
different aspects of the call to the $QIO service. The
condition value returned in R0 provides information about the
success or failure of the service call itself; the condition
values returned in the I/O status block give information on
the success or failure of the service operation. Therefore, to
determine the success or failure of the $QIO call, check the
condition values returned in both the R0 and the I/O status
block.
astadr
OpenVMS usage:ast_procedure
type: procedure value
access: call without stack unwinding
mechanism: (Alpha and I64) by 32- or 64-bit reference
(VAX) by 32-bit reference
AST service routine to be executed when the I/O completes. The
astadr argument is the address of the AST routine.
The AST routine executes at the access mode of the caller of
$QIO.
astprm
OpenVMS usage:user_arg
type: quadword unsigned (Alpha and I64); longword
unsigned (VAX)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit value
(VAX) by 32-bit value
AST parameter to be passed to the AST service routine. On
Alpha and I64 systems, the astprm argument is a quadword value
containing the AST parameter. On VAX systems, the astprm argument
is a longword value containing the AST parameter.
p1 to p6
OpenVMS usage:varying_arg
type: quadword unsigned (Alpha and I64); longword
unsigned (VAX)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit reference or by
64-bit value depending on the I/O function
(VAX) by 32-bit reference or by 32-bit value
depending on the I/O function
Optional device- and function-specific I/O request arguments. The
parameter values contained in these arguments vary according to
the function for which they are used. See Network Pseudodevice
Driver Functions for descriptions of the network pseudodevice
driver I/O function codes.
4.2 – Description
The Queue I/O Request service operates only on assigned I/O
channels and only from access modes that are equal to or more
privileged than the access mode from which the original channel
assignment was made.
For TCP/IP Services, $QIO uses the following system resources:
o The process's AST limit (ASTLM) quota, if an AST service
routine is specified.
o System dynamic memory, which is required to queue the I/O
request. System dynamic memory requirements are protocol
specific.
o Additional memory, on a device-dependent basis.
For $QIO, completion can be synchronized as follows:
o By specifying the astadr argument to have an AST routine
execute when the I/O is completed.
o By calling the $SYNCH synchronize service to await completion
of the I/O operation. (If you want your I/O operation to
complete synchronously, use the $QIOW system service instead.)
4.3 – Condition Values Returned
Each function used with $QIO has its own error codes. See the
error codes listed under the individual descriptions of the I/O
function code in the remainder of this chapter.
4.4 – Network Pseudodevice Driver Functions
The network pseudodevice allows physical, logical, and virtual
I/O functions. The physical and logical I/O functions are used
only with the IP layer. See the following table for a list of the
basic I/O functions and their modifiers. The sections that follow
describe in greater detail the operation of these I/O functions.
The following table describes the network pseudodevice driver I/O
functions.
Function Code and Function
Arguments Modifier Description
IO$_ACCESS p3,p4 IO$M_ACCEPT Opens a connection.
IO$M_EXTEND
IO$M_NOW
IO$_ACPCONTROL p1, Performs an ACP (ancillary
p2, p3, p4 control process) operation.
IO$_DEACCESS p4 IO$M_NOW Aborts or closes a
IO$M_SHUTDOWN connection.
IO$_READVBLK IO$M_EXTEND Reads a virtual block.
p1,p2,p3,p4,p6 IO$M_
INTERRUPT
IO$M_LOCKBUF Controls the buffer
IO$M_PURGE operations.
IO$_SENSEMODE Reads the network
p2,p3,p4,p6 pseudodevice
characteristics.
IO$_SENSECHAR Reads the network
p2,p3,p4,p6 pseudodevice
characteristics.
IO$_SETMODE p1,p2, IO$M_OUTBAND Sets the network
p3,p4,p5 IO$M_READATTN pseudodevice characteristics
IO$M_WRTATTN for subsequent operations.
IO$_SETCHAR p1,p2, IO$M_OUTBAND Sets the network
p3,p4,p5 IO$M_READATTN pseudodevice characteristics
IO$M_WRTEATTN for subsequent operations.
IO$_WRITEVBLK IO$M_ Writes a virtual block.
p1,p2,p3,p4,p5 INTERRUPT
4.4.1 – IO$_ACCESS
When using a connection-oriented protocol, such as TCP, the IO$_
ACCESS function initiates a connection and specifies a remote
port number and IP address. When using a connectionless protocol,
such as UDP, the IO$_ACCESS function sets the remote port number
and IP address.
For TCP, a connection request times out at a specified interval
(75 seconds is the default). This interval can be changed by
setting the inet subsystem parameter tcp_keepinit. The program
can also set a specific timeout interval for a socket that it has
created, as described in TCP Protocol Options.
If a connection fails, you must deallocate the socket and then
create a new socket before trying to reconnect.
Related Functions
The equivalent Sockets API function is connect().
4.4.1.1 – Arguments
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_2 descriptor
The remote port number and IP address of the host to connect.
The p3 argument is the address of an item_list_2 descriptor that
points to the socket address structure containing the remote port
number and IP address.
4.4.1.2 – Function Modifiers
IO$M_NOW Regardless of a $QIO or $QIOW, if the system
detects a condition that would cause the
operation to block, the system completes the
I/O operation and returns the SS$_SUSPENDED
status code.
4.4.1.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_BADPARAM Programming error that occurred for one of the
following reasons:
o $QIO system service was specified without a
socket.
o An IO$_ACCESS function was specified
without the address of a remote socket
name (p3 was null).
SS$_BUGCHECK Inconsistent state. Report the problem to your
HP support representative.
SS$_CANCEL The I/O operation was canceled by a $CANCEL
system service.
SS$_CONNECFAIL The connection to a network object timed out
or failed.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_DUPLNAM A network configuration error. No ports were
available for new connections.
SS$_EXQUOTA The process has exceeded a process quota.
SS$_FILALRACC The specified socket name is already in use by
one of the following:
o On a raw socket, the remote IP address was
already specified on a previous IO$_ACCESS
call.
o On a datagram, the remote IP address was
already specified on a previous IO$_ACCESS
call.
o On a stream socket, the IO$_ACCESS function
targeted a stream socket that was already
connected.
SS$_ILLCNTRFUNC Illegal function.
SS$_INSFMEM Insufficient system dynamic memory to complete
the service.
SS$_IVADDR The specified IP address was not found, or an
invalid port number and IP address combination
was specified with the IO$_ACCESS function.
Port 0 is not allowed with the IO$_ACCESS
function.
SS$_IVBUFLEN The size of the socket name structure
specified with the IO$_ACCESS function was
invalid.
SS$_LINKABORT The remote socket closed the connection.
SS$_NOLICENSE The TCP/IP Services license is not present.
SS$_PROTOCOL A network protocol error occurred. The
address family specified in the socket address
structure is not supported.
SS$_REJECT The network connection is rejected for one of
the following reasons:
o An attempt was made to connect to a remote
socket that is already connected.
o An error was encountered while establishing
the connection
o The peer socket refused the connection
request or is closing the connection.
SS$_SHUT The local or remote node is no longer
accepting connections.
SS$_SUSPENDED The system detected a condition that might
cause the operation to block.
SS$_TIMEOUT A TCP connection timed out before the
connection could be established.
SS$_UNREACHABLE The remote node is currently unreachable.
4.4.2 – IO$_ACCESS|IO$M_ACCEPT
This function is used with a connection-based protocol, such as
TCP, to accept a new connection on a passive socket.
This function completes the first connection on the queue of
pending connections.
Related Functions
The equivalent Sockets API function is accept() .
4.4.2.1 – Arguments
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_3 descriptor
The remote port number and IP address of a new connection. The p3
argument is the address of an item_list_3 descriptor that points
to the socket address structure into which the remote port number
and IP address of the new connection is written.
p4
OpenVMS usage:channel
type: word (unsigned)
access: write only
mechanism: by reference
The I/O channel number assigned to a new connection. The p4
argument is the address of a word into which the new connection's
channel number is written.
4.4.2.2 – Function Modifiers
IO$M_EXTEND Allows the usage of BSD Version 4.4 formatted
socket address structures. Use this modifier
to operate in the IPv6 environment.
IO$M_NOW Regardless of a $QIO or $QIOW, if the system
detects a condition that would cause the
operation to block, the system completes the
I/O operation and returns the SS$_SUSPENDED
status code.
4.4.2.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_BADPARAM Programming error that occurred for one of the
following reasons:
o $QIO system service was specified without a
socket.
o A IO$_ACCESS|IO$M_ACCEPT function was
specified without the address of the
channel for the new connection (p4 was
null or invalid).
SS$_BUGCHECK Inconsistent state. Report the problem to your
HP support representative.
SS$_CANCEL The I/O operation was canceled by a $CANCEL
system service.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_EXQUOTA The process has exceeded a process quota.
SS$_FILALRACC The specified socket name is already in use by
one of the following:
o On a raw socket, the remote IP address was
already specified on a previous IO$_ACCESS
call.
o On a datagram, the remote IP address was
already specified on a previous IO$_ACCESS
call.
o On a stream socket, the IO$_ACCESS function
targeted a stream socket that was already
connected.
SS$_ILLCNTRFUNC Illegal function.
SS$_INSFMEM Insufficient system dynamic memory to complete
the service.
SS$_IVADDR The specified IP address was not found, or an
invalid port number and IP address combination
was specified with the IO$_ACCESS function.
Port 0 is not allowed with the IO$_ACCESS
function.
SS$_IVBUFLEN The size of the socket name structure
specified with the IO$_ACCESS function was
invalid.
SS$_LINKABORT The remote socket closed the connection.
SS$_NOLICENSE The TCP/IP Services license is not present.
SS$_PROTOCOL A network protocol error occurred. The
address family specified in the socket address
structure is not supported.
SS$_REJECT The network connection is rejected for one of
the following reasons:
o An attempt was made to connect to a remote
socket that is already connected.
o An error was encountered while establishing
the connection
o The peer socket refused the connection
request or is closing the connection.
SS$_SHUT The local or remote node is no longer
accepting connections.
SS$_SUSPENDED The system detected a condition that might
cause the operation to block.
SS$_TIMEOUT A TCP connection timed out before the
connection could be established.
SS$_UNREACHABLE The remote node is currently unreachable.
4.4.3 – IO$_ACPCONTROL
The IO$_ACPCONTROL function accesses the network ACP to retrieve
information from the host and the network database files.
Related Functions
The equivalent Sockets API functions are gethostbyaddr(),
gethostbyname(), getnetbyaddr(), and getnetbyname().
4.4.3.1 – Arguments
p1
OpenVMS usage:subfunction_code
type: longword (unsigned)
access: read only
mechanism: by descriptor-fixed-length descriptor
A longword identifying the network ACP operation to perform.
The p1 argument is the address of a descriptor pointing to this
longword.
To specify the network ACP operation to perform, select a
subfunction code from the first table below and a call code from
the second table.
The following table defines subfunction codes for network ACP
operations.
.
Subfunction Code Description
INETACP_FUNC$C_ Get the host name of the specified IP
GETHOSTBYADDR address from the hosts database.
INETACP_FUNC$C_ Get the IP address of the specified
GETHOSTBYNAME host from the hosts database.
INETACP_FUNC$C_ Get the network name of the specified
GETNETBYADDR IP address from the network database.
INETACP_FUNC$C_ Get the IP address of the specified
GETNETBYNAME network from the network database.
The following table defines call codes for network ACP
operations.
Call Code Description
INETACP$C_ALIASES Returns the list of alias names associated
with the specified host or network from
the internet hosts or network database.
INETACP$C_TRANS Returns the IP address associated with
the specified host or network as a 32-bit
value in network byte order.
INETACPC$C_HOSTENT_ Returns full host information in a
OFFSET modified hostent structure. In the
modified structure, pointers are replaced
with offsets from the beginning of the
structure.
INETACP$C_NETENT_ Returns full network information in
OFFSET a modified netent structure. In the
modified structure, pointers are replaced
with offsets from the beginning of the
structure.
IO$_ACPCONTROL searches the local hosts database for the host's
name. If a matching host name is not found in the local hosts
database, IO$_ACPCONTROL then searches the BIND database if the
BIND resolver is enabled.
p2
OpenVMS usage:char_string
type: character-coded text string
access: read only
mechanism: by descriptor-fixed-length string descriptor
Input string for the network ACP operation containing one of
the following: host IP address, host name, network IP address,
or network name. The p2 argument is the address of a string
descriptor pointing to the input string. The input string must
be in an area of memory that is capable of being read and written
to.
All IP addresses are specified in dotted-decimal notation.
p3
OpenVMS usage:word_unsigned
type: word (unsigned)
access: write only
mechanism: by reference
Length in bytes of the output buffer returned by IO$_ACPCONTROL.
The p3 argument is the address of a word in which the length of
the output buffer is written.
p4
OpenVMS usage:buffer
type: vector byte (unsigned)
access: write only
mechanism: by descriptor-fixed-length descriptor
Buffer into which IO$_ACPCONTROL writes its output data. The p4
argument is the address of a descriptor pointing to the output
buffer.
The format of the data returned in the output buffer is dictated
by the call code specified by the p1 argument.
o Strings returned by IO$_ACPCONTROL with a call code of
INETACP$C_ALIASES consist of one of the following: host IP
address, host name, network IP address, or network name. All
IP addresses are formatted using dotted-decimal notation.
Alias names are separated by a null character (0). The length
of the returned string includes all null characters that
separate alias names.
o IP addresses returned by IO$_ACPCONTROL with a call code of
INETACP$C_TRANS are 32-bit values in network byte order.
o All hostent and netent structures returned by IO$_
ACPCONTROL with a call code of INETACP$C_HOSTENT_OFFSET or
INETACP$C_NETENT_OFFSET are modified; pointers are replaced
with offsets from the beginning of the structure.
4.4.3.2 – Condition Values Returned
SS$_NORMAL The service completed successfully
SS$_ABORT An error was detected while performing an ACP
function.
SS$_BADPARAM Programming or internal error. A bad parameter
(name or address) was specified in the call.
SS$_BUFFEROVF Programming error. There was not enough space
for returning all alias names in the call.
SS$_ENDOFFILE The information requested is not in the
database.
SS$_ILLCNTRFUNC Illegal function.
SS$_NOPRIV The privilege level was insufficient for the
execution of an ACP function.
SS$_RESULTOVF The ACP overflowed the buffer in returning a
parameter.
SS$_SHUT The local or remote node is no longer
accepting connections.
4.4.4 – IO$_DEACCESS
The IO$_DEACCESS function closes a connection and deletes a
socket. Any pending messages queued for transmission are sent
before tearing down the connection.
When used with the IO$M_SHUTDOWN function modifier, the IO$_
DEACCESS function shuts down all or part of a bidirectional
connection on a socket. Use the p4 argument to specify the
disposition of pending I/O operations on the socket.
You can specify a wait time or time-to-linger socket parameter
(TCPIP$C_LINGER option) for transmission completion before
disconnecting the connection. Use the IO$_SETMODE function to
set and clear the TCPIP$C_LINGER option.
If you set the TCPIP$C_LINGER option, a $QIO call that uses the
IO$_DEACCESS function allows data queued to the socket to arrive
at the destination. The system is blocked until data arrives at
the remote socket. The socket data structure remains open for the
duration of the TCP idle time interval.
If you do not set the TCPIP$C_LINGER option (option is set to 0),
a $QIO call that uses the IO$_DEACCESS function discards any data
queued to the socket and deallocates the socket data structure.
NOTE
For compatibility with UNIX, TCP/IP Services forces a time
to linger of 2 minutes on TCP stream sockets.
Related Functions
The equivalent Sockets API functions are close() and shutdown().
4.4.4.1 – Arguments
p4
OpenVMS usage:mask_longword
type: longword (unsigned)
access: read only
mechanism: by value
Longword of shutdown flags to specify the disposition of pending
I/O operations on the socket. The p4 argument is used only with
the IO$M_SHUTDOWN function modifier. The following table lists
available shutdown flags.
Shutdown Flag Description
TCPIP$C_DSC_ Discards messages from the receive queue and
RCV disallows further receiving. Pending messages
in the receive queue for this connection are
discarded.
TCPIP$C_DSC_ Discards messages from the send queue and
SND disallows sending new messages. Pending messages
in the transmit queue for this connection are
discarded.
TCPIP$C_DSC_ Discards all messages and disallows both
ALL sending and receiving. All pending messages are
discarded.
Specifying this flag has the same effect as
issuing a $CANCEL QIO followed by an IO$_DEACCESS
QIO without specifying any flags.
4.4.4.2 – Function Modifiers
IO$M_SHUTDOWN Causes all or part of a full-duplex connection
on a socket to be shut down.
IO$M_NOW Regardless of a $QIO or $QIOW, if the system
detects a condition that would cause the
operation to block, the system completes the
I/O operation and returns the SS$_SUSPENDED
status code.
4.4.4.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_BADPARAM The IO$_DEACCESS operation failed to specify a
socket.
SS$_CANCEL The I/O operation was canceled by a $CANCEL
system service.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_NOLINKS The specified socket was not connected.
SS$_SHUT The local or remote node is no longer
accepting connections.
SS$_SUSPENDED The system detected a condition that might
cause the operation to block.
4.4.5 – IO$_READVBLK
The IO$_READVBLK function transfers data received from an
internet host to the specified user buffers. Use both p1 and
p2 arguments to specify a single user buffer. Use the p6 argument
to specify multiple buffers.
For connection-oriented protocols, such as TCP, data is buffered
in system space as a stream of bytes. The IO$_READVBLK function
completes when one of the following occurs:
o There is no more data buffered in system space for this
socket.
o There is no more available space in the user buffer. Data that
is buffered in system space but did not fit in the user buffer
is available to the user in subsequent $QIOs.
For connectionless protocols, datagram and raw socket data is
buffered in system space as a chain of records. The user buffer
specified with a IO$_READVBLK function is filled with data that
is buffered in one record. Each IO$_READVBLK reads data from
one record. The IO$_READVBLK function completes when one of the
following occurs:
o All data from a record is transferred to the user buffer.
o There is no more available space in the user buffer. Any data
remaining in the current record that did not fit in the user
buffer is discarded. A subsequent $QIO reads data from the
next record buffered in system space.
Use the TCP/IP management command SHOW DEVICE_SOCKET/FULL to
display counters related to read operations.
Related Functions
The equivalent Sockets API functions are read(), recv(),
recvfrom(), and recvmsg().
4.4.5.1 – Arguments
p1
OpenVMS usage:buffer
type: vector byte (unsigned)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit reference
(VAX) by 32-bit reference
The address of the buffer to receive the incoming data. The
length of this buffer is specified by the p2 argument.
p2
OpenVMS usage:buffer_length
type:
access: quadword unsigned (Alpha and I64); longword
unsigned (VAX)
mechanism: read only
(Alpha and I64) by 64-bit value
The length (in bytes) of the buffer available to hold the
incoming data. The address of this buffer is specified by the
p1 argument.
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_3 descriptor
The remote port number and IP address of the source of the
datagram or raw IP message (not TCP). The p3 argument is the
address of an item_list_3 descriptor that points to the socket
address structure into which the remote port number and IP
address of the message source is written.
p4
OpenVMS usage:mask_longword
type: longword (unsigned)
access: read only
mechanism: by value
Longword of flags to specify attributes for the read operations.
The following table lists the available read flags.
Read Flag Description
TCPIP$C_MSG_OOB Reads an out-of-band byte.
TCPIP$C_MSG_PEEK Reads a message but leaves the message in the
queue.
TCPIP$C_MSG_NBIO Does not block the I/O operation if the
receive queue is empty (similar to using
IO$M_NOWAIT).
TCPIP$C_MSG_PURGE Flushes data from the queue (similar to using
IO$M_PURGE).
TCPIP$C_MSG_ Blocks the completion of the operation until
BLOCKALL the buffer is filled completely or until the
connection is closed (similar to using IO$M_
LOCKBUF).
p6
OpenVMS usage:buffer_list
type: vector byte (unsigned)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit
descriptor-fixed-length descriptor
(VAX) by 32-bit descriptor-fixed-length descriptor
Output buffer list describing one or more buffers to hold the
incoming data. The p6 argument is the 32- or 64-bit address (on
Alpha and I64 systems) or the 32-bit address (on VAX systems)
of a descriptor that points to a output buffer list. Buffers
are filled in the order specified by the output buffer list. The
transfer-length value returned in the I/O status block is the
total number of bytes transferred to all buffers.
If you use the p1 and p2 arguments, do not use the p6 argument;
they are mutually exclusive.
4.4.5.2 – Function Modifiers
IO$M_EXTEND Specifies the format of the socket address
structure to return when used with the p3
argument.
When specified, a BSD Version 4.4 formatted
socket address structure is returned that
identifies the source of the received UDP
datagram or raw IP message.
To operate in an IPv6 environment, you must
set the IO$M_EXTEND modifier.
IO$M_INTERRUPT Reads an out-of-band (OOB) message. This
has the same effect as specifying the
TCPIP$C_MSG_OOB flag in the p4 argument.
On receiving an OOB character, TCP/IP stores
the pointer in the received stream with the
character that precedes the OOB character.
A read operation with a user-buffer size
larger than the size of the received stream
up to the OOB character completes and returns
to the user the received stream up to, but not
including, the OOB character.
To determine whether the socket must issue
more read $QIOs before getting all the
characters from the stream preceding an OOB
character, poll the socket. To do this, issue
a $QIO with the $IO_SENSEMODE function, and
the TCPIP$C_IOCTL subfunction that specifies
the SIOCATMARK command. The SIOCATMARK values
are as follows:
o 0 = Issue more read $QIOs to read more data
before reading the OOB.
o 1 = The next read $QIO will return the OOB
character.
Polling a socket is particularly useful
when the OOBINLINE socket option is set.
When the OOBINLINE is set, TCP/IP reads the
OOB character with the characters in the
stream (IO$_READVBLK), but not before reading
the preceding characters. Use this polling
mechanism to determine whether the first
character in the user buffer on the next read
is an OOB character.
On a socket without the OOBINLINE option
set, a received OOB character will always
be read by issuing a $QIO with either the
IO$_READVBLK|IO$M_INTERRUPT or IO$_READVBLK
and the TCPIP$C_MSG_OOB flag set. This
can occur regardless of how many preceding
characters in the stream have been returned to
the user.
IO$M_LOCKBUF Blocks the completion of the I/O operation
until the user buffer is completely filled
or until the connection is closed. This
is particularly useful when you want to
minimize the number of $QIO service calls
issued to read a data stream of a set size.
This function modifier supports only stream
protocols.
IO$M_NOWAIT Regardless of a $QIO or $QIOW, if the
system detects a condition that would
cause the operation to block, the system
completes the I/O operation and returns the
SS$_SUSPENDED status code.
IO$M_PURGE Flushes data from the socket receive queue
(discards data). If the user buffer is larger
than the amount of data in the queue, all data
is flushed.
4.4.5.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ABORT Programming error, INET management error, or
hardware error. The execution of the I/O was
aborted.
SS$_ACCVIO Access to an invalid memory location or buffer
occurred.
SS$_BADPARAM One of the following methods was used to
specify a $QIO function with an invalid
parameter:
o An I/O function executed without specifying
a device socket. First issue a $QIO with
the IO$_SETMODE function and the proper
parameters to create the device socket.
o An IO$_READVBLK function that does not
specify a correct buffer address (p1 or p6
is null).
o An IO$_READVBLK function specified an
invalid vectored buffer (p6 is an invalid
descriptor).
o The socket has the OOBINLINE option set,
or there is no OOB character in the
socket's OOB queue because the character
was either already read or never received.
This condition happens only if you use
the IO$M_INTERRUPT modifier or set the
TCPIP$C_MSG_OOB flag with IO$_READVBLK.
SS$_CANCEL The I/O operation was canceled by a $CANCEL
system service.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_INSFMEM INET management or programming error. There
is not enough buffer space for allocation.
The INET software needs more buffer space.
You should set a higher quota for the dynamic
buffer space, or shut down and restart TCP/IP
Services with a larger static buffer space.
SS$_IVBUFLEN Programming error occurred for one of the
following reasons:
o The size of the buffer for an I/O function
is insufficient.
o An IO$_READVBLK specified a correct buffer
address (p1 valid), but does not specify a
buffer length (p2 is null).
SS$_LINKDISCON A virtual circuit (TCP/IP) was closed at the
initiative of the peer.
SS$_NOLINKS Programming error. Read attempt on unconnected
TCP socket.
SS$_SHUT The network is being shut down.
SS$_SUSPENDED The operation is blocked for one of the
following reasons:
o No messages were received, so the receive
operation cannot complete. The socket is
marked as nonblocking.
o The socket has the OOBINLINE option clear,
and the OOB character has already been
read.
SS$_TIMEOUT This applies to a socket that has KEEPALIVE
set. The connection was idle for longer
than the timeout interval (10 minutes is
the default). For more information, see TCP
Protocol Options.
SS$_UNREACHABLE Communication status. The remote host or
network is unreachable.
4.4.6 – IO$_SENSEMODE/IO$_SENSECHAR
The IO$_SENSEMODE and IO$_SENSECHAR functions return one or more
parameters (characteristics) pertaining to the network driver.
Socket names (local and remote peer) are returned by using IO$_
SENSEMODE's p3 and p4 arguments. Other parameters such as socket
and protocol options, are specified in an output parameter list
using the IO$_SENSEMODE p6 argument.
IO$_SENSEMODE p3 and p4 arguments can be used with the p6
argument in a single $QIO system service to return socket names
as well as socket and protocol options. IO$_SENSEMODE processes
arguments in this order: p3, p4, p6. If IO$_SENSEMODE detects
an error, the I/O status block (IOSB) contains the error and
argument address or the value that was at fault.
Refer to individual argument descriptions for details about
specifying the type and format of output parameters.
4.4.6.1 – Arguments
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_3 descriptor
The port number and IP address of the local name associated with
the socket. The p3 argument is the address of an item_list_3
descriptor that points to the socket address structure into which
the local name is written.
The equivalent Sockets API function is getsockname().
p4
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_3 descriptor
The port number and IP address of the remote name associated with
the socket's peer. The p4 argument is the address of an item_
list_3 descriptor that points to the socket address structure
into which the peer name is written.
The equivalent Sockets API function is getpeername().
p6
OpenVMS usage:output_parameter_list
type: vector byte (unsigned)
access: read only
mechanism: by item_list_2 descriptor
Output parameter list describing one or more parameters to
return. The p6 argument is the address of an item_list_2
descriptor that points to and identifies the type of output
parameter list.
The equivalent Sockets API functions are getsockopt() and
ioctl().
4.4.6.2 – Function Modifiers
IO$M_EXTEND Specifies the format of the socket address
structure to return when used with the p3 or
p4 arguments.
When specified, a BSD Version 4.4 formatted
socket address structure is returned.
Specify the IO$M_EXTEND modifier to operate in
an IPv6 environment.
4.4.6.3 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ACCVIO The service cannot access a buffer specified
by one or more arguments.
SS$_BADPARAM Programming error occurred for one of the
following reasons:
o $QIO system service was specified without a
socket.
o Error occurred processing a socket or
protocol option.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_ILLCNTRFUNC Programming error. The operation is
unsupported for one of the following reasons:
o An invalid IO$_SENSEMODE function for the
interface was specified. The interface does
not have an IOCTL routine.
o An IO$_SENSEMODE function that requires a
socket was specified, but the device did
not have one. Create a socket and then
issue the function.
o An unsupported operation was performed on
at least one of the following protocols:
raw IP, datagram, or stream sockets.
SS$_INSFMEM Insufficient system dynamic memory to complete
the service.
SS$_IVBUFLEN The size of a socket option buffer specified
with the IO$_SENSEMODE function was invalid.
SS$_NOSUCHDEV Programming error or INET management error. An
INET address is not in the Address Resolution
Protocol (ARP) table. An attempt to show or
delete an ARP table entry failed.
SS$_NOLINKS The specified socket was not connected.
SS$_NOOPER Programming error. An attempt to get ARP
information occurred without OPER privilege.
SS$_PROTOCOL A network protocol error occurred. The
address family specified in the socket address
structure is not supported.
SS$_SHUT The local or remote node is no longer
accepting connections.
SS$_UNREACHABLE The remote node is currently unreachable.
4.4.7 – IO$_SETMODE/IO$_SETCHAR
The IO$_SETMODE and IO$_SETCHAR functions set one or more
parameters (characteristics) pertaining to the network driver.
Sockets are created using the IO$_SETMODE p1 argument. Names are
assigned to sockets using the IO$_SETMODE p3 argument. Active
sockets are converted to passive sockets using the IO$_SETMODE p4
argument. Other parameters, such as socket and protocol options,
are specified in an input parameter list using the IO$_SETMODE p5
argument.
The IO$_SETMODE p1, p3, and p4 arguments can be used with the
p5 argument in a single $QIO system service to set socket names
as well as socket and protocol options. IO$_SETMODE processes
arguments in this order: p1, p3, p4, p5. If IO$_SETMODE detects
an error, the I/O status block (IOSB) contains the error and
argument address or the value that was at fault.
Refer to individual argument descriptions for details about
specifying the type and format of input parameters.
4.4.7.1 – Arguments
p1
OpenVMS usage:socket_characteristics
type: longword (unsigned)
access: read only
mechanism: by reference
Longword specifying the protocol, socket type, and address family
of a new socket. The p1 argument is the address of the longword
containing the socket characteristics.
The newly created socket is marked privileged if the image that
creates a socket runs in a process that has BYPASS, OPER, or
SYSPRV privilege.
The following table shows protocol codes:
Protocol Description
TCPIP$C_TCP TCP/IP protocol
TCPIP$C_UDP UDP/IP protocol
TCPIP$C_RAW_IP IP protocol
The following table lists the valid socket types.
Socket Type Description
TCPIP$C_STREAM Permits bidirectional, reliable, sequenced,
and unduplicated data flow without record
boundaries.
TCPIP$C_DGRAM Permits bidirectional data flow with record
boundaries. No provisions for sequencing,
reliability, or unduplicated messages.
TCPIP$C_RAW Permits access to the IP layer; used to develop
new protocols that are layered upon the IP
layer.
The following table shows address family codes:
Address Family Description
TCPIP$C_AF_INET IPv4 Internet domain (default).
TCPIP$C_AF_ IPv6 Internet domain.
INET6
TCPIP$C_AUXS Accept hand-off of a socket already created and
initialized by the auxiliary server.
The equivalent Sockets API function is socket().
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_2 descriptor
The local name (that is, port number and IP address) to assign
to the socket. The p3 argument is the address of an item_list_2
descriptor that points to the socket address structure containing
the local name.
The equivalent Sockets API function is bind() .
p4
OpenVMS usage:connection_backlog
type: byte (unsigned)
access: read only
mechanism: by value
Maximum limit of outstanding connection requests for a socket
that is connection oriented. If more connection requests are
received than are specified, the additional requests are ignored
so that TCP retries can succeed.
The equivalent Sockets API function is listen().
p5
OpenVMS usage:input_parameter_list
type: vector byte (unsigned)
access: read only
mechanism: by item_list_2 descriptor
Input parameter list describing one or more parameters to set.
The p5 argument is the address of an item_list_2 descriptor that
points to and identifies the type of input parameter list.
The equivalent Sockets API functions are setsockopt() and
ioctl().
4.4.7.2 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ACCVIO The service cannot access a buffer specified
by one or more arguments.
SS$_BADPARAM Programming error that occurred for one of the
following reasons:
o $QIO system service was specified without a
socket.
o Error occurred processing a socket or
protocol option.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_DUPLNAM Programming error. The port being bound is
already in use. An attempt to bind the socket
to an address and port failed.
SS$_FILALRACC Programming error. The IP address is already
in use. An attempt to bind the socket to an
address and port failed.
SS$_ILLCNTRFUNC Programming error. An attempt to perform an
IO$_SETMODE function required a socket, but
the device did not have one. Create a socket
before issuing the function.
SS$_IVADDR Programming error. The IP address you
specified using the IO$_SETMODE function was
not placed into the system. This resulted
in an invalid port number or IP address
combination. The IP address was invalid for
one of the following reasons:
o An attempt was made to exceed the limit
of allowable permanent entries in the ARP
table.
o An attempt was made to bind a raw IP socket
when there are no interfaces defined in the
system.
o An attempt was made to bind a raw IP socket
to a null Internet address.
SS$_INSFMEM Insufficient system dynamic memory to complete
the service.
SS$_IVBUFLEN The size of a socket option buffer specified
with the IO$_SETMODE function was invalid.
SS$_NOLICENSE Programming or system management error. A
TCP/IP Services license is not present.
SS$_NOOPER Programming or INET management error. An
attempt to was made to execute an I/O function
that needs the OPER privilege.
SS$_NOPRIV Programming or INET management error. There
are not enough privileges for the attempted
operation for one of the following reasons:
o An attempt was made to broadcast an IP
datagram on a process without SYSPRV,
BYPASS, or OPER privilege.
o An attempt was made to use a reserved port
number lower than 1024.
o An attempt was made to access a process
that requires SYSPRV or BYPASS privilege.
o An attempt was made to use raw IP on a
privileged socket that requires the SYSPRV
or BYPASS privilege.
SS$_NOSUCHDEV Programming error or INET management error.
An attempt was made to show or delete an ARP
table entry failed because the IP address is
not found.
SS$_NOSUCHNODE Programming error or INET management error.
An attempt was made to delete a route from the
routing table failed because the entry was not
found.
SS$_PROTOCOL Programming error. A specified protocol or
address family caused an error for one of the
following reasons:
o An invalid protocol type was specified at
socket creation.
o An unsupported protocol was specified.
o The address family is unsupported for one
of the following reasons:
- An unsupported address family was
specified. Instead, specify the
address family (TCPIP$C_AF_INET,
TCPIP$C_AF_INET6, or TCPIP$C_UNSPEC).
- An unsupported address family for
the local IP address was specified.
Instead, specify the address family
(TCPIP$C_AF_INET or TCPIP$C_AF_INET6).
- An unsupported address family for
the IP address of the routing module
was specified. Instead, specify the
address family (TCPIP$C_AF_INET or
TCPIP$C_AF_INET6).
SS$_SHUT The local or remote node is no longer
accepting connections.
4.4.8 – IO$_SETMODE|IO$M_OUTBAND
The IO$_SETMODE|IO$M_OUTBAND function/modifier combination
requests that the asynchronous system trap (AST) for an out-
of-band (OOB) character be delivered to the requesting process.
This is to be done only when an OOB character is received on the
socket and there is no waiting read request. The socket must be a
TCP (stream) socket.
The Enable OOB character AST function allows an Attention AST
to be delivered to the requesting process only once. After the
AST occurs, the function must explicitly reenable AST delivery
before a new AST can be delivered. This function is subject to
AST quotas.
4.4.8.1 – Arguments
p1
OpenVMS usage:ast_procedure
type: procedure value
access: call without stack unwinding
mechanism: by reference
To enable the AST, the p1 argument is the address of the OOB
character AST routine. To disable the AST, p1 equals 0.
p2
OpenVMS usage:user_arg
type: longword (unsigned)
access: read only
mechanism: by value
AST parameter to be delivered to the AST routine specified by the
p1 argument.
p3
OpenVMS usage:access_mode
type: longword (unsigned)
access: read only
mechanism: by value
Access mode to deliver the AST.
4.4.8.2 – Condition Values Returned
SS$_NORMAL The service completed successfully.
SS$_ABORT Programming, INET management, or hardware
error.
SS$_ACCVIO Programming error. An attempt to access an
invalid memory location or buffer occurred.
SS$_BADPARAM Programming error. A $QIO service with an
invalid parameter occurred for one of the
following reasons:
o An attempt was made to execute an IO$_
SETMODE function (all functions except
socket creation) without specifying a
device socket. Instead, create a device
socket by issuing a $QIO with the IO$_
SETMODE function and correct parameters.
o A socket option was specified incorrectly.
SS$_DEVACTIVE INET management error. An attempt to change
the static parameters occurred. If new
parameters are needed, restart TCP/IP
Services.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded but the INET_ACP
is not currently available for use.
SS$_DUPLNAM Programming error. An attempt to bind a port
that is already in use occurred. An attempt to
bind the socket to an address and port failed.
SS$_FILALRACC Programming error. IP address is already
in use. An attempt to bind the socket to an
address and port failed.
SS$_INSFMEM Programming or system management error: Not
enough resources to allocate new socket.
SS$_ILLCNTRFUNC Programming error. Operation is not supported
because of one of the following reasons:
o Invalid IO$_SETMODE (IOCTL) function was
used for the interface. The interface does
not have an IOCTL routine.
o An attempt was made to perform an
IO$_SETMODE (IOCTL) function that required
a socket, but the device did not have
one. Create a socket and issue the IOCTL
function.
SS$_IVADDR The specified IP address was not found, or an
invalid port number and IP address combination
was specified. Port 0 is not allowed with this
function.
SS$_IVBUFLEN Programming error. The socket option buffer
has an invalid size.
SS$_NOLICENSE Programming or system management error. The
TCP/IP Services license is not present.
SS$_NOOPER Programming or INET management error. An
attempt was made to execute an I/O function
that needs the OPER privilege.
SS$_NOPRIV Programming or INET management error. Not
enough privileges for the attempted operation
for one of the following reasons:
o Broadcasting an IP datagram was denied
because the process does not have SYSPRV,
BYPASS, or OPER privilege.
o An attempt was made to use a reserved port
number lower than 1024.
o An operation accesses only processes that
have SYSPRV or BYPASS privilege.
o Raw IP protocol can be used only on
privileged sockets. The process must have a
SYSPRV or BYPASS privilege.
SS$_NOSUCHDEV Programming error or INET management error.
An INET address is not in the ARP table. An
attempt to show or delete an ARP table entry
failed.
SS$_NOSUCHNODE Programming or INET management error. An
attempt to delete a route from the routing
table failed because a route entry was not
found.
SS$_PROTOCOL Programming error. The specified protocol type
is not supported.
SS$_SHUT The local or remote node is no longer
accepting connections.
4.4.9 – IO$_SETMODE|IO$M_READATTN
The IO$_SETMODE|IO$M_READATTN function/modifier combination
requests that an Attention AST be delivered to the requesting
process when a data packet is received on the socket and there is
no waiting read request.
The Enable Read Attention AST function enables an Attention AST
to be delivered to the requesting process only once. After the
AST occurs, the function must explicitly reenable AST delivery
before the AST can occur again. The function is subject to AST
quotas.
Consider the following when using IO$M_READATTN:
o There is a one-to-one correspondence between the number of
times you enable an Attention AST and the number of times the
AST is delivered. For each enabled AST, one AST is delivered.
If you enable an Attention AST several times, several ASTs are
delivered for one event when an event occurs.
o If an out-of-band (OOB) Attention AST is enabled, the OOB AST
is delivered, regardless of the following:
- An enabled Read Attention AST
- The TCPIP$C_OOBINLINE socket option
- A READ $QIO waiting for completion on the socket
If the TCPIP$C_OOBINLINE option is set, then a waiting READ
$QIO is completed and the OOB character is returned in the data
stream.
o If both an OOB AST and a Read Attention AST are enabled, only
the OOB AST is delivered when an OOB character is received.
o If a Read Attention AST is enabled and the TCPIP$C_OOBINLINE
socket option is set, a waiting READ $QIO completes and the
OOB character is returned in the data stream.
o If a Read Attention AST is enabled and the TCPIP$C_OOBINLINE
socket option is not set (clear), the Read Attention AST
is delivered when an OOB character is received, regardless
of whether a READ $QIO is waiting for completion. In this
case, the OOB character is not returned in the data stream.
Therefore, if the OOB character is the only character
received, the READ $QIO does not complete.
4.4.9.1 – Arguments
p1
OpenVMS usage:ast_procedure
type: procedure value
access: call without stack unwinding
mechanism: by reference
To enable the AST, the p1 argument is the address of the Read
Attention AST routine. To disable the AST, set p1 to 0.
p2
OpenVMS usage:user_arg
type: longword (unsigned)
access: read only
mechanism: by value
AST parameter to be delivered to the AST routine.
p3
OpenVMS usage:access_mode
type: longword (unsigned)
access: read only
mechanism: by value
Access mode in which the AST is delivered.
4.4.9.2 – Condition Values Returned
SS$_ABORT Programming, INET management, or hardware
error. The route entry already exists, so
the attempt to add a route entry using the
IO$_SETMODE function failed.
SS$_ACCVIO Programming error. An attempt to access an
invalid memory location or buffer occurred.
SS$_BADPARAM Programming error. The parameter specified
for a $QIO function was invalid for one of the
following reasons:
o An attempt to execute the IO$_SETMODE
functions without specifying a device
socket occurred. Instead, create a device
socket by issuing a $QIO with the IO$_
SETMODE function and the proper parameters.
o A socket option was specified incorrectly.
SS$_DEVACTIVE INET management error. An attempt to change a
static parameter was unsuccessful. If you need
new parameters, restart TCP/IP Services.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded but the INET_ACP
is not currently available for use.
SS$_DUPLNAM Programming error. An attempt to bind a port
already in use occurred so the operation
to bind the socket to the address and port
failed.
SS$_FILALRACC Programming error. An attempt to bind the
socket to an address that is already in use
occurred and the operation failed.
SS$_INSFMEM Programming or system management error. The
system does not have enough resources to
allocate new socket.
SS$_ILLCNTRFUNC Programming error. Operation is not supported.
o Invalid IO$_SETMODE (IOCTL) function was
used for the interface. The interface does
not have an IOCTL routine.
o An attempt was made to perform an
IO$_SETMODE (IOCTL) function that required
a socket, but the device did not have
one. Create a socket and issue the IOCTL
function.
SS$_IVADDR Programming error. The specified IP address
is not in the system, and an invalid port
number or an invalid IP address combination
was specified with an IO$_SETMODE function (a
bind).
o An attempt to bind the address failed
because the IP address is not in the
system, Port 0 and IP address 0 are not
allowed, or Port 0 is not allowed when
using an IO$_ACCESS function.
o An attempt was made to make a permanent
entry in the ARP table failed because of
lack of space. Too many permanent entries.
o An attempt was made to bind an IP socket
(raw IP) when there are no interfaces
defined in the system.
o An attempt was made to bind an IP socket
(raw IP) to a null INET address.
SS$_IVBUFLEN Programming error. The socket option buffer
has an invalid size.
SS$_NOLICENSE Programming or system management error. The
TCP/IP Services license is not present.
SS$_NOOPER Programming or INET management error. An
attempt was made to execute an I/O function
that needs the OPER privilege.
SS$_NOPRIV Programming or INET management error. Not
enough privileges for the attempted operation.
o Broadcasting an IP datagram was denied
because the process does not have SYSPRV,
BYPASS, or OPER privilege.
o An attempt was made to use a reserved port
number lower than 1024.
o An operation accesses only processes that
have SYSPRV or BYPASS privilege.
o Raw IP protocol can be used only on
privileged sockets. The process must have a
SYSPRV or BYPASS privilege.
SS$_NOSUCHDEV Programming error or INET management error. An
Internet address is not in the ARP table. An
attempt to show or delete an ARP table entry
failed.
SS$_NOSUCHNODE Programming error or INET management error.
An attempt to delete a route from the routing
table failed because a route entry was not
found.
SS$_PROTOCOL Programming error. The specified protocol type
is not supported.
SS$_SHUT The local or remote node is no longer
accepting connections.
4.4.10 – IO$_SETMODE|IO$M_WRTATTN
The IO$_SETMODE|IO$M_WRTATTN function/modifier combination (IO$M_
WRTATTN is Enable Write Attention AST) requests that an Attention
AST be delivered to the requesting process when a data packet can
be queued to the socket. For TCP sockets, this occurs when space
becomes available in the TCP transmit queue.
The Enable Write Attention AST function enables an Attention AST
to be delivered to the requesting process only once. After the
AST occurs, the function must explicitly reenable AST delivery
before the AST can occur again. The function is subject to AST
quotas.
There is a one-to-one correspondence between the number of
times you enable an Attention AST and the number of times the
AST is delivered. For example, for each enabled AST, one AST is
delivered. If you enable an Attention AST several times, several
ASTs are delivered for one event when the event occurs.
You can use the TCP/IP management command SHOW DEVICE_SOCKET to
display information about the socket's characteristics, options,
and state.
4.4.10.1 – Arguments
p1
OpenVMS usage:ast_procedure
type: procedure value
access: call without stack unwinding
mechanism: by reference
To enable the AST, the p1 argument is the address of the Write
Attention AST routine. To disable the AST, p1 is set to 0.
p2
OpenVMS usage:user_arg
type: longword (unsigned)
access: read only
mechanism: by value
AST parameter to be delivered to the AST routine.
p3
OpenVMS usage:access_mode
type: longword (unsigned)
access: read only
mechanism: by value
Access mode in which the AST is delivered.
4.4.10.2 – Condition Values Returned
SS$_ABORT Programming error, INET management error,
or hardware error. The route specified with
the IO$_SETMODE function already exists.
Therefore, the operation failed.
SS$_ACCVIO Programming error. An attempt to access an
invalid memory location or buffer occurred.
SS$_BADPARAM Programming error. The parameter specified for
the $QIO I/O function was invalid for one of
the following reasons:
o An attempt was made to execute the IO$_
SETMODE functions without specifying a
device socket. Instead, create a device
socket by issuing a $QIO with the IO$_
SETMODE function and the proper parameters.
o A socket option was specified incorrectly.
SS$_DEVACTIVE INET management error. You attempted to
change the static parameters. If you need
new parameters, restart TCP/IP Services.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded but the INET_ACP
is not currently available for use.
SS$_DUPLNAM Programming error. Port that is being bound is
already in use. An attempt to bind the socket
to an address and port failed.
SS$_FILALRACC Programming error. Because the IP address is
already in use, an attempt to bind the socket
to an address and port failed.
SS$_INSFMEM Programming or system management error. There
are not enough resources to allocate a new
socket.
SS$_ILLCNTRFUNC Programming error. An attempt was made to
execute an IO$_SETMODE function that required
a socket, but the device did not have one.
Instead, create a socket and issue the
function.
SS$_IVADDR Programming error. An invalid port number and
IP address combination was specified with the
IO$_SETMODE bind function. This caused the
operation to fail for one of the following
reasons:
o An illegal combination of Port 0 and IP
address 0 was specified.
o An attempt was made to make a permanent
entry in the ARP table and the operation
failed because of lack of space. There are
too many permanent entries.
o An attempt was made to bind a raw IP socket
when there were no interfaces defined in
the system.
o An attempt was made to bind a raw IP socket
to a null IP address.
SS$_IVBUFLEN Programming error. An invalid size was
specified for the socket option buffer.
SS$_NOLICENSE Programming or system management error. The
TCP/IP Services license is not present.
SS$_NOOPER Programming or INET management error. An
attempt was made to execute an I/O function
that needs the OPER privilege.
SS$_NOPRIV Programming or INET management error. The
operation failed for one of the following
reasons:
o An attempt was made to broadcast an IP
datagram for a process without having
SYSPRV, BYPASS, or OPER privilege.
o An attempt was made to use a reserved port
number lower than 1024.
o An attempt was made to access a process
without having SYSPRV or BYPASS privilege.
o An attempt was made to use raw IP on a
socket that is not a privileged socket. To
do this, the process must have SYSPRV or
BYPASS privilege.
SS$_NOSUCHDEV Programming error or INET management error.
An attempt was made to show or delete an
entry in the ARP table. However, because
the IP address was not in the ARP table, the
operation failed.
SS$_NOSUCHNODE Programming error or INET management error.
An attempt was made to delete a route from
the routing information table (RIT). However,
because the route was not found in the RIT,
the operation failed.
SS$_PROTOCOL Programming error. The specified protocol is
not supported.
SS$_SHUT The local or remote node is no longer
accepting connections.
4.4.11 – IO$_WRITEVBLK
The IO$_WRITEVBLK function transmits data from the specified
user buffers to an Internet host. Use both p1 and p2 arguments
to specify a single user buffer. Use the p5 argument to specify
multiple buffers.
For connection-oriented protocols, such as TCP, if the socket
transmit buffer is full, the IO$_WRITEVBLK function is blocked
until the socket transmit buffer has room for the user data.
For connectionless-oriented protocols, such as UDP and raw IP,
the user data is transmitted in one datagram. If the user data
is greater than the socket's transmit quota, the error code (SS$_
TOOMUCHDATA) is returned.
Related Functions
The equivalent Sockets API functions are send(), sendto(),
sendmsg(), and write().
4.4.11.1 – Arguments
p1
OpenVMS usage:buffer
type: vector byte (unsigned)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit reference
(VAX) by 32-bit reference
The address of the buffer containing the data to be transmitted.
The length of this buffer is specified by the p2 argument.
p2
OpenVMS usage:buffer_length
type: quadword unsigned (Alpha and I64); longword
unsigned (VAX)
access: read only
mechanism: (Alpha and I64) by 64-bit value
(VAX) by 32-bit value
The length (in bytes) of the buffer containing data to be
transmitted. The address of this buffer is specified by the p1
argument.
p3
OpenVMS usage:socket_name
type: vector byte (unsigned)
access: read only
mechanism: by item_list_2 descriptor
The remote port number and IP address of the message destination.
The p3 argument is the address of an item_list_2 descriptor
pointing to the socket address structure containing the remote
port number and IP address.
p4
OpenVMS usage:mask_longword
type: longword (unsigned)
access: read only
mechanism: by value
Longword of flags to specify attributes for this write operation.
The following table lists the available write flags:
Write Flag Description
TCPIP$C_MSG_OOB Writes an out-of-band (OOB) byte.
TCPIP$C_MSG_ Sends message directly without routing.
DONTROUTE
TCPIP$C_MSG_NBIO Completes the I/O operation and returns
an error if a condition arises that would
cause the I/O operation to be blocked.
(Similar to using IO$M_NOWAIT.)
p5
OpenVMS usage:buffer_list
type: vector byte (unsigned)
access: read only
mechanism: (Alpha and I64) by 32- or 64-bit
descriptor-fixed-length descriptor
(VAX) by 32-bit descriptor-fixed-length descriptor
Input buffer list describing one or more buffers containing
the data to be transmitted. The p5 argument is the address
of a descriptor pointing to a input buffer list. Buffers are
transmitted in the order specified by the input buffer list. The
transfer-length value returned in the I/O status block is the
total number of bytes transferred from all buffers.
If you use the p1 and p2 arguments, do not use the p5 argument;
they are mutually exclusive.
4.4.11.2 – Function Modifiers
IO$M_EXTEND Allows the use of extended modifiers with BSD
Version 4.4. Valid only for datagram sockets
(UDP or raw IP); ignored for TCP.
IO$M_INTERRUPT Sends an OOB message.
IO$M_NOWAIT Regardless of a $QIO or $QIOW, if the system
detects a condition that would cause the
operation to block, the system completes the
I/O operation and returns the SS$_SUSPENDED
status code.
When using this function modified, always
check the message length in the IOSB to ensure
that all data is transferred. IO$_WRITEVBLK
returns a success status even if data is only
partially transferred.
4.4.11.3 – Condition Values Returned
SS$_ABORT Programming error, INET management error, or
hardware error. The execution of the I/O was
aborted.
SS$_ACCVIO Programming error. An attempt was made to
access an invalid memory location or buffer.
SS$_BADPARAM Programming error. An I/O operation was
specified using an invalid parameter.
o An attempt was made to execute an
IO$_WRITEVBLK function without specifying a
device socket. First create a device socket
by issuing an IO$_SETMODE function and the
proper arguments.
o An attempt was made to issue an
IO$_WRITEVBLK function that did not specify
a correct buffer address (p1 or p5 is
null).
o An attempt was made to issue an
IO$_WRITEVBLK that specifies an invalid
vectored buffer (p5 specifies an invalid
address descriptor).
SS$_CANCEL The I/O operation was canceled by the $CANCEL
system service.
SS$_DEVINTACT The network driver was not started.
SS$_DEVNOTMOUNT The network driver is loaded, but the INETACP
is not currently available for use.
SS$_EXQUOTA Returned when process resource mode wait is
disabled. There is no Internet request packet
(IRP) available for completing the request.
Increase the buffered I/O quota.
SS$_FILALRACC Programming error.
o IP address is already in use. An attempt
was made to bind the socket to an address
but the port failed.
o IP protocol (raw socket). An attempt was
made to specify a remote socket address
with an IO$_WRITEVBLK function, while an
IP address was already specified with an
IO$_ACCESS function.
o UDP/IP protocol. An attempt was made to
specify a remote socket address with an
IO$_WRITEVBLK function, while an IP address
was already specified with the IO$_ACCESS
function.
SS$_ILLCNTRFUNC Programming error. Unsupported operation on
the protocol (UDP or TCP).
SS$_INSFMEM Insufficient system dynamic memory to complete
the operation.
SS$_IVADDR Programming error. The specified IP address is
not in the system, and an invalid port number
or an IP address combination was specified
with an IO$_WRITEVBLK operation.
o An attempt to bind the socket failed
because the INET address is not in the
system, Port 0 and IP address 0 are not
allowed, or Port 0 is not allowed with an
IO$_WRITEVBLK function.
o An attempt to get an interface IP address,
broadcast mask, or network mask failed.
o A send request was made on a datagram-
oriented protocol, but the destination
address is unknown or not specified.
SS$_IVBUFLEN Programming error.
o The size of the buffer for an I/O function
is insufficient.
o An attempt was made to issue an
IO$_WRITEVBLK function that specifies a
correct buffer address (p1 valid) but does
not specify a buffer length (p2 is null).
SS$_LINKDISCON Notification. Connection completion return
code. The virtual circuit (TCP/IP) was closed
at the initiative of the peer. The application
must stop sending data and must either shut
down or close the socket.
SS$_PROTOCOL Programming error. The address family of the
remote address specified with an IO$_WRITEVBLK
function is not supported (UDP or TCP).
The address family should be either the
TCPIP$C_AF_INET or the TCPIP$C_AF_INET6
address family.
SS$_NOLINKS Programming error. The socket was not
connected (TCP), or an INET port and address
were not specified with an IO$_ACCESS (UDP).
o An IO$_WRITEVBLK with no remote INET socket
address was issued on a socket that was not
the object of an IO$_ACCESS function (raw
IP).
o An IO$_WRITEVBLK with no remote INET socket
address was issued on a socket that was not
the object of an IO$_ACCESS function (UDP).
o An attempt was made to disconnect a socket
that is not connected, or an attempt was
made to issue an IO$_WRITEVBLK function on
an unconnected socket (TCP).
SS$_SHUT The local or remote node is no longer
accepting connections.
SS$_SUSPENDED The system detected a condition that might
cause the operation to block.
SS$_TIMEOUT Programming error, INET management error, or
hardware error.
o A TCP/IP connection timed out after several
unsuccessful retransmissions.
o On a TCP socket where KEEPALIVE is set,
the connection was idle for longer than
the timeout interval. The default is 10
minutes.
SS$_TOOMUCHDATA Programming or INET management error. The
message size was too large.
o An IP packet that is broadcast cannot be
fragmented.
o The Not Fragment IP flag was set and the IP
datagram was too large to be sent without
being fragmented.
o Internal error. The length of the Ethernet
datagram does not allow enough space for
the minimum IP header.
o The message to be sent on a UDP or raw IP
socket is larger than the socket buffer
high water allows. For more information,
see IOCTL Requests.
o An attempt was made to send or receive
more than 16 buffers specified with the p5
argument.
SS$_UNREACHABLE Communication status. The remote host is
currently unreachable.
This indicates a hardware error. The data link
adapter detected an error and shut itself off.
The TCP/IP Services software is waiting for
the adapter to come back on line.
4.5 – TELNET Port Driver $QIO Interface
The TELNET port driver (TNDRIVER) provides terminal session
support for TCP streaming connections using the RAW, NVT, RLOGIN,
and TELNET protocols. Either a remote device or an application
can be present at the remote endpoint of the connection.
A user program can manage a TELNET connection with the standard
OpenVMS $QIO system service by using the IO$_TTY_PORT and IO$_
TTY_PORT_BUFIO I/O function codes.
4.5.1 – Interface Definition
The following definitions are used by the interface. The symbols
are defined in SYS$LIBRARY:TNIODEF.H.
4.5.1.1 – Item List Codes
The following table describes the symbols used with the p5
parameter.
Maximum
Item Code Size Description
TN$_ACCPORNAM 64 Access port name string. When
written, the string's length is
determined by the item_length
field. The value of item_length
should not be more than 63 bytes.
When read, the string is returned
in ASCIC format (the first byte
contains the string's length), so a
size of 64 is appropriate.
TN$_ 4 Characteristics mask. This longword
CHARACTERISTICS contains a bit mask of the device's
characteristics read or to be
written. (See Characteristic Mask
Bits for a table that describes the
characteristic mask bits.)
TN$_CONNECTION_ 4 Reconnection attempts. This item
ATTEMPTS is the number of unsuccessful
reconnection attempts which have
been made on a reconnectable
device. The value will be
reinitialized when a successful
connection is made. This item is
read only.
TN$_CONNECTION_ 4 Minimum time (in seconds) before
INTERVAL reconnection attempts.
TN$_CONNECTION_ 4 Current time (in seconds) since
TIMEOUT the last reconnection attempt. This
item is read only.
TN$_DATA_HIGH 4 Maximum amount of output data (in
bytes) buffered at the network
port. This number does not affect
the amount of data buffered within
the socket.
TN$_DEVICE_UNIT 4 Terminal device unit number. When
written, this value must be between
1 and 9999.
TN$_IDLE_INTERVAL 4 Maximum idle time (in seconds)
allowed before a connection is
to be broken. Connections are not
broken if the device is stalled.
TN$_IDLE_TIMEOUT 4 Current time (in seconds) since
last output on the terminal. This
item is read only.
TN$_LOCAL_ADDRESS 32 Local sockaddr of the active
connection. When written, the
value of item_length determines
the size of the sockaddr. Note that
the sockaddr is in BSD Version 4.4
format, which includes a sockaddr
size field. (C programs should be
compiled with the _SOCKADDR_LEN
symbol defined.) This item is read
only.
TN$_NETWORK_ 64 Name of the network pseudodevice
DEVICE_NAME currently bound to the terminal.
When read, the data is returned
in ASCIC format (the first byte
contains the string's length). This
item is read only.
TN$_PROTOCOL 4 Session protocol. (See the table in
Protocol Types.)
TN$_REMOTE_ADDRESS 32 Remote peer's sockaddr of the
active connection. Note that
the sockaddr is in BSD Version
4.4 format, which includes a
sockaddr size field. The size of
the sockaddr should be determined
from this field. This item is read
only.
TN$_SERVICE_TYPE 4 Class of terminal service. (See the
table in Service Types.)
TN$_STATUS 4 Current device and session status.
This item is read only.
4.5.1.2 – Characteristic Mask Bits
The following table describes the characteristic mask bits used
with the p5 parameter.
Characteristic Description
TN$M_AUTOCONNECT The device supports automatic
connect/reconnect.
TN$M_LOGIN_ON_ Initiate a login when the TELNET device is
DASSGN deassigned. This characteristic requires the
BYPASS or SYSNAM privilege or executive or
kernel mode calls.
TN$M_LOGIN_TIMER Used in conjunction with TN$M_LOGIN_ON_DASSGN,
this bit indicates that the login completion
timer applies. If the TN device fails to
login within 60 seconds, the connection will
be broken and the device deallocated. This
characteristic requires the BYPASS or SYSNAM
privileges or executive or kernel mode calls.
TN$M_PERMANENT_ The TELNET device is to remain until
UCB explicitly deleted.
TN$M_RETAIN_ON_ The TELNET device is not to be deleted upon
DASSGN the deassignment of the last channel to this
device. This condition is cleared on this
last deassignment, so that a subsequent assign
and deassign will result in the device being
deleted.
TN$M_VIRTUAL_ When logging in under this device, a virtual
TERMINAL terminal is to be created by TTDRIVER.
4.5.1.3 – Protocol Types
The following table describes the protocol types used with the p5
parameter.
Protocol Type Description
TN$K_PROTOCOL_ There is no explicit protocol for this
UNDEFINED session. Data is transmitted and received
on the socket without any interpretation.
This is a raw connection.
TN$K_PROTOCOL_NVT Network Virtual Terminal (NVT) protocol.
The protocol understands basic session
control but does not include the options
negotiation present in the TELNET
protocol.
TN$K_PROTOCOL_RLOGIN BSD Remote Login protocol. This simple
protocol provides some special control
character support but lacks the
architecture independence of the NVT and
TELNET protocols.
TN$K_PROTOCOL_TELNET TELNET protocol. Including the basic NVT
protocol, TELNET adds support for options
negotiation. This can provide an enhanced
terminal session depending upon the client
and server involved.
4.5.1.4 – Service Types
The following table describes the service type codes used with
the p5 parameter.
Service Type Description
TN$K_SERVICE_NONE The service type is not currently known.
TN$K_SERVICE_ The service is an incoming connection.
INCOMING
TN$K_SERVICE_ The service is an outgoing connection.
OUTGOING
4.5.2 – Passing Parameters to the TELNET Port Driver
The IO$_TTY_PORT function is used to pass $QIO parameters
through the terminal driver to the TELNET port driver. The actual
subfunction is encoded as an option mask and may be:
o IO$M_TN_STARTUP - Bind socket to a TELNET terminal.
o IO$M_TN_SHUTDOWN - Unbind socket from a TELNET terminal.
4.6 – IO$_TTY_PORT|IO$M_TN_STARTUP
Bind socket to a TELNET terminal.
This subfunction will bind a created (connected) socket to a
TELNET terminal device.
4.6.1 – Arguments
p1
OpenVMS usage:channel
type: word (unsigned)
access: read only
mechanism: by value
The p1 argument contains the channel number of the socket over
which the TELNET session is to be established.
p2
OpenVMS usage:protocol_number
type: longword (unsigned)
access: read only
mechanism: by value
The p2 argument contains the protocol selection.
p3
OpenVMS usage:characteristics_mask
type: longword (unsigned)
access: read only
mechanism: by value
The p3 argument specifies a mask of characteristics to apply
against the connection. See the table in Item List Codes under
Interface Definition help for possible values.
4.6.2 – Description
The IO$M_TN_STARTUP subfunction allows the application to
communicate over a socket using the terminal driver QIO
interface. Note that incoming and outgoing data is processed
by the terminal driver, and that the terminal's characteristics
may affect the format of the data. Be aware that by default, the
terminal will echo incoming data back to the sender.
Once the subfunction completes, the application is free to
perform all terminal QIO functions on the connection. While the
socket is bound to a terminal device, it will process neither the
IO$_READxBLK nor the IO$_WRITExBLK function, and will return the
error SS$_DEVINUSE.
4.6.3 – Condition Values Returned
SS$_IVCHAN Programming error. The specified channel is
not valid.
SS$_IVMODE Programming error. The access mode of the
channel is more privileged than the access
mode of the terminal's channel.
SS$_NOPRIV Programming error. The TN$M_LOGIN_ON_
DASSGN characteristic was specified in a
characteristics mask from a $QIO in USER or
SUPERVISOR mode without either the BYPASS or
SYSPRV privilege.
SS$_NOTNETDEV Programming error. The specified channel is an
assignment to a non-BG device.
SS$_PROTOCOL Programming error. The specified protocol
number is not valid, or the network is not
available.
4.7 – IO$_TTY_PORT|IO$M_TN_SHUTDOWN
Unbind socket from a TELNET terminal.
This subfunction will unbind a previously bound socket-terminal
connection.
4.7.1 – Arguments
p1
OpenVMS usage:channel
type: word (unsigned)
access: read only
mechanism: by value
The p1 argument contains the channel number of the socket to
establish the TELNET session.
4.7.2 – Description
The IO$M_TN_SHUTDOWN subfunction allows the application to break
a previously bound socket-terminal connection (created with IO$M_
TN_STARTUP). The channel must be from an assignment to the same
network pseudodevice in the socket-terminal connection.
Upon completion, the application retains the assignments to
the connection and the TELNET terminal, but they are no longer
related. Any subsequent IO$_READxBLK or IO$_WRITExBLK function on
the socket channel will no longer return the error SS$_DEVINUSE.
4.7.3 – Condition Values Returned
SS$_IVCHAN Programming error. The specified channel is
not valid.
SS$_IVMODE Programming error. The access mode of the
channel is more privileged than the access
mode of the terminal's channel.
SS$_NOTNETDEV Programming error. The specified channel is an
assignment to a non-BG device.
SS$_DEVREQERR Programming error. The device on the channel
does not match the device in the socket-
terminal connection.
4.7.4 – Buffered Reading and Writing of Item Lists
The IO$_TTY_PORT_BUFIO function is used to pass $QIO parameters
through the terminal driver to the TELNET port driver. IO$_TTY_
PORT_BUFIO differs from IO$_TTY_PORT in that certain subfunctions
accept buffered item lists for reading or writing parameters to
the terminal device.
o IO$M_TN_SENSEMODE - Read device parameters.
o IO$M_TN_SETMODE - Write device parameters.
The subfunctions of IO$_TTY_PORT_BUFIO accept an item list for
input or output. Subfunction Item List shows the format of this
item list.
The item list is terminated with an item_code and item_length,
both of which are zero.
The subfunctions of IO$_TTY_PORT_BUFIO can be combined into
a single $QIO. For example, the IO$M_TN_SETMODE and IO$M_TN_
CONNECT can be combined to set the device's parameters and then
to attempt to make a connection.
The subfunctions are performed in the following order:
1. IO$M_TN_SETMODE
2. IO$M_TN_CONNECT
3. IO$M_TN_SENSEMODE
4. IO$M_TN_DISCON
NOTE
Certain items are read only (IO$M_TN_SENSEMODE) and cannot
be written (IO$M_TN_SETMODE). Normally, attempting to write
such items would result in the error SS$_BADATTRIB. However,
if a combination operation (IO$M_TN_SENSEMODE|IO$M_TN_
SETMODE) is being performed, these items will not result
in an error. Rather, the items will be ignored in the IO$M_
TN_SETMODE processing, and the $QIO will continue with IO$M_
TN_SENSEMODE processing, returning the information that the
item specifies.
4.7.5 – IO$_TTY_PORT_BUFIO|IO$M_TN_SENSEMODE
Read device parameters.
4.7.5.1 – Arguments
p5
OpenVMS usage:item_list_2
type: vector byte (unsigned)
access: read only
mechanism: by reference
The p5 argument is the address of an item list that contains a
summary of information to be read from the device.
4.7.5.2 – Description
The IO$M_TN_SENSEMODE subfunction of IO$_TTY_PORT_BUFIO is used
to read the parameters associated with a device.
4.7.5.3 – Condition Values Returned
SS$_BADATTRIB Programming error. The item code within the
list is not valid. This could be because of
its code, an attempt to write a read-only
parameter, or inappropriate size. The address
of the item's buffer is returned in the second
longword of the I/O status block.
SS$_IVBUFLEN Programming error. The length of the specified
item is not acceptable. The address of the
item's buffer is returned in the second
longword of the I/O status block.
SS$_NOPRIV Programming error. An item that requires a
privilege which the requestor does not have
is present in the item list. The address of
the item's buffer is returned in the second
longword of the I/O status block.
4.7.6 – IO$_TTY_PORT_BUFIO|IO$M_TN_SETMODE
Write device parameters.
4.7.6.1 – Arguments
p5
OpenVMS usage:item_list_2
type: vector (byte unsigned)
access: read only
mechanism: by reference
The p5 argument is the address of an item list that contains a
summary of information to be written to the device.
4.7.6.2 – Description
The IO$M_TN_SETMODE subfunction of IO$_TTY_PORT_BUFIO is used to
write the parameters associated with a device.
4.7.6.3 – Condition Values Returned
SS$_BADATTRIB Programming error. The item code within the
list is not valid. This could be because of
its code, an attempt to write a read-only
parameter, or inappropriate size. The address
of the item's buffer is returned in the second
longword of the I/O status block.
SS$_DUPLNAM Programming error. An attempt to set the
device's unit number via the TN$_DEVICE_UNIT
item has failed because that specified unit
number was already present.
SS$_IVBUFLEN Programming error. The length of the specified
item is not acceptable. The address of the
item's buffer is returned in the second
longword of the I/O status block.
SS$_NOPRIV Programming error. An item that requires a
privilege which the requester does not have
is present in the item list. The address of
the item's buffer is returned in the second
longword of the I/O status block.