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.\"	Fraunhofer Institute for Open Communication Systems (FhG Fokus).
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.\" Author: Hartmut Brandt <harti@FreeBSD.org>
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.Dd March 3, 2023
.Dt NG_UNI 4
.Os
.Sh NAME
.Nm ng_uni
.Nd netgraph UNI node type
.Sh SYNOPSIS
.In netnatm/msg/unistruct.h
.In netnatm/sig/unidef.h
.In netgraph/atm/ng_uni.h
.Sh DEPRECATION NOTICE
.Nm
is deprecated and may not be available in
.Fx 14.0
and later.
.Sh DESCRIPTION
The
.Nm uni
netgraph node type implements ATM Forum signalling 4.0.
.Pp
After creation of the node, the UNI instance must be created by sending
an
.Dq enable
message to the node.
If the node is enabled, the UNI parameters
can be retrieved and modified, and the protocol can be started.
.Pp
The node is shut down either by an
.Dv NGM_SHUTDOWN
message, or when all hooks are disconnected.
.Sh HOOKS
Each
.Nm uni
node has three hooks with fixed names:
.Bl -tag -width ".Va upper"
.It Va lower
This hook is the interface of the UNI protocol to the transport layer of
the ATM control plane.
The node expects the interface exported by
.Xr ng_sscfu 4
at this hook.
.It Va upper
This hook is the
.Dq user
interface of the UNI protocol.
Because there is no standardized interface
at this point, this implementation follows more or less the interface
specified by the SDL diagrams in ITU-T recommendations Q.2931 and Q.2971.
Normally either a
.Xr ng_ccatm 4
or a switch CAC should be stacked at this interface.
The message format at the
.Va upper
hook is described below.
Because
.Xr netgraph 4
is functional, it makes sometimes sense to switch this hook to queueing mode
from the peer node upon connection.
.El
.Pp
The
.Va upper
interface of the
.Nm uni
node is loosely modelled after the interface specified in the ITU-T signalling
standards.
There is however one derivation from this: normally there exists
four kinds of signals: requests, responses, indications and confirmations.
These signals are usually triggered either by external events (receiving a
message) or internal events (a timer or another signal).
This scheme works
fine for user APIs that are entirely asynchronous, and in cases where
error handling is not taken into account.
With synchronous APIs and error
handling however, there is a problem.
If, for example, the application
issues a request to set up a connection,
it may do it by sending a
.Dv SETUP.request
signal to the UNI.
Normally, the UNI stack will send a SETUP message and
receive a message from the switch (a RELEASE, CONNECT, CALL PROCEEDING or
ALERTING), or a timer in the UNI stack will time out.
In any of these cases,
the UNI stack is supposed to report an event back to the application, and
the application will unblock (in the case of a synchronous API) and handle
the event.
The problem occurs when an error happens.
Suppose there is no
memory to send the SETUP message and to start the timer.
In this case, the
application will block forever because no received message and no timer
will wake it up.
For this reason this implementation uses an additional message:
for each signal sent from the application to the stack, the stack will
respond with an error code.
If this code is zero, the stack has accepted
the signal and the application may block; if the code is non-zero, the signal
is effectively ignored and the code describes what was wrong.
This system
makes it very easy to make a blocking interface out of the message based
netgraph interface.
.Pp
The
.Va upper
interface uses the following structure:
.Bd -literal
struct uni_arg {
	uint32_t	sig;
	uint32_t	cookie;
	u_char		data[];
};
.Ed
The
.Va sig
field contains the actual signal that is sent from the user to UNI or from
UNI to the user.
The
.Va cookie
can be used by the user to correlate requests with events and responses.
If an error response, a confirmation or an indication was triggered by
a request or response, the cookie from that request or response is carried in
the message from the stack to the user.
The
.Va cookie
field is followed by the actual data for the signal.
.Pp
The signal is one of the following:
.Bd -literal
enum uni_sig {
    UNIAPI_ERROR,			/* UNI -> API */

    UNIAPI_CALL_CREATED,		/* UNI -> API */
    UNIAPI_CALL_DESTROYED,		/* UNI -> API */
    UNIAPI_PARTY_CREATED,		/* UNI -> API */
    UNIAPI_PARTY_DESTROYED,		/* UNI -> API */

    UNIAPI_LINK_ESTABLISH_request,	/* API -> UNI */
    UNIAPI_LINK_ESTABLISH_confirm,	/* UNI -> API */
    UNIAPI_LINK_RELEASE_request,	/* API -> UNI */
    UNIAPI_LINK_RELEASE_confirm,	/* UNI -> API */

    UNIAPI_RESET_request,		/* API -> UNI */
    UNIAPI_RESET_confirm,		/* UNI -> API */
    UNIAPI_RESET_indication,		/* UNI -> API */
    UNIAPI_RESET_ERROR_indication,	/* UNI -> API */
    UNIAPI_RESET_response,		/* API -> UNI */
    UNIAPI_RESET_ERROR_response,	/* API -> UNI */
    UNIAPI_RESET_STATUS_indication,	/* UNI -> API */

    UNIAPI_SETUP_request,		/* API -> UNI */
    UNIAPI_SETUP_indication,		/* UNI -> API */
    UNIAPI_SETUP_response,		/* API -> UNI */
    UNIAPI_SETUP_confirm,		/* UNI -> API */
    UNIAPI_SETUP_COMPLETE_indication,	/* UNI -> API */
    UNIAPI_ALERTING_request,		/* API -> UNI */
    UNIAPI_ALERTING_indication,		/* UNI -> API */
    UNIAPI_PROCEEDING_request,		/* API -> UNI */
    UNIAPI_PROCEEDING_indication,	/* UNI -> API */
    UNIAPI_RELEASE_request,		/* API -> UNI */
    UNIAPI_RELEASE_indication,		/* UNI -> API */
    UNIAPI_RELEASE_response,		/* API -> UNI */
    UNIAPI_RELEASE_confirm,		/* UNI -> API */
    UNIAPI_NOTIFY_request,		/* API -> UNI */
    UNIAPI_NOTIFY_indication,		/* UNI -> API */
    UNIAPI_STATUS_indication,		/* UNI -> API */
    UNIAPI_STATUS_ENQUIRY_request,	/* API -> UNI */

    UNIAPI_ADD_PARTY_request,		/* API -> UNI */
    UNIAPI_ADD_PARTY_indication,	/* UNI -> API */
    UNIAPI_PARTY_ALERTING_request,	/* API -> UNI */
    UNIAPI_PARTY_ALERTING_indication,	/* UNI -> API */
    UNIAPI_ADD_PARTY_ACK_request,	/* API -> UNI */
    UNIAPI_ADD_PARTY_ACK_indication,	/* UNI -> API */
    UNIAPI_ADD_PARTY_REJ_request,	/* API -> UNI */
    UNIAPI_ADD_PARTY_REJ_indication,	/* UNI -> API */
    UNIAPI_DROP_PARTY_request,		/* API -> UNI */
    UNIAPI_DROP_PARTY_indication,	/* UNI -> API */
    UNIAPI_DROP_PARTY_ACK_request,	/* API -> UNI */
    UNIAPI_DROP_PARTY_ACK_indication,	/* UNI -> API */

    UNIAPI_ABORT_CALL_request,		/* API -> UNI */

    UNIAPI_MAXSIG
};
.Ed
.Pp
The meaning of most of the signals can be deduced from the ITU-T SDLs.
A number of signals, however, is unique to this implementation:
.Bl -tag -width foo
.It Dv UNIAPI_ERROR
This is the error response, mentioned earlier.
It carries an error code or
zero, if the signal was accepted by the stack.
.It Dv UNIAPI_CALL_CREATED
The UNI stack has created a call instance either from an incoming SETUP or
from the user requesting an outgoing SETUP.
This may be used to synchronize
the creation and destroying of call data between the UNI stack and the user.
.It Dv UNIAPI_CALL_DESTROYED
A call instance has been destroyed and all resources have been freed.
.It Dv UNIAPI_PARTY_CREATED
A new party has been created for an existing point-to-multipoint call.
This may be used to synchronize the creation and destroying of party data
between the UNI stack and the user.
.It Dv UNIAPI_PARTY_DESTROYED
A party has been destroyed and all resources have been freed.
.It Dv UNIAPI_ABORT_CALL_request
This requests the stack to destroy the call instance
and free all its resources,
without sending any messages to the network.
.It Dv UNIAPI_MAXSIG
This is not a signal, but rather a definition to get the number of defined
signals.
.El
.Pp
Each of the signals is followed by a fixed size structure defined in
.In netnatm/sig/unidef.h .
.Sh CONTROL MESSAGES
The
.Nm uni
node understands the standard control messages, plus the following:
.Bl -tag -width foo
.It Dv NGM_UNI_SETDEBUG Pq Ic setdebug
Set debugging facility levels.
The UNI stack defines a number of debugging
facilities, each one associated with a debugging level.
If the debugging level
of a facility is non-zero, text output will be generated to the console.
The message uses the following structure:
.Bd -literal
struct ngm_uni_debug {
	uint32_t	level[UNI_MAXFACILITY];
};
.Ed
.It Dv NGM_UNI_GETDEBUG Pq Ic getdebug
Get debugging facility levels.
This returns an
.Vt ngm_uni_debug
structure.
.It Dv NGM_UNI_GET_CONFIG Pq Ic get_config
Retrieve the current configuration of the UNI instance.
This message returns a
.Vt uni_config
structure:
.Bd -literal
struct uni_config {
	uint32_t proto;		/* which protocol */
	uint32_t popt;		/* protocol option */
	uint32_t option;	/* other options */
	uint32_t timer301;	/* T301 */
	uint32_t timer303;	/* T303 */
	uint32_t init303;	/* T303 retransmission count */
	uint32_t timer308;	/* T308 */
	uint32_t init308;	/* T308 retransmission count */
	uint32_t timer309;	/* T309 */
	uint32_t timer310;	/* T310 */
	uint32_t timer313;	/* T313 */
	uint32_t timer316;	/* T316 */
	uint32_t init316;	/* T316 retransmission count */
	uint32_t timer317;	/* T317 */
	uint32_t timer322;	/* T322 */
	uint32_t init322;	/* T322 retransmission count */
	uint32_t timer397;	/* T397 */
	uint32_t timer398;	/* T398 */
	uint32_t timer399;	/* T399 */
};
.Ed
.Pp
The field
.Va proto
specifies one of the following protocols:
.Bd -literal
enum uni_proto {
	UNIPROTO_UNI40U,	/* UNI4.0 user side */
	UNIPROTO_UNI40N,	/* UNI4.0 network side */
	UNIPROTO_PNNI10,	/* PNNI1.0 */
};
.Ed
.Pp
Some protocols may have options which can be set in
.Va popt :
.Bd -literal
enum uni_popt {
	UNIPROTO_GFP,		/* enable GFP */
};
.Ed
.Pp
The
.Va option
field controls parsing and checking of messages:
.Bd -literal
enum uni_option {
	UNIOPT_GIT_HARD,	/* harder check of GIT IE */
	UNIOPT_BEARER_HARD,	/* harder check of BEARER IE */
	UNIOPT_CAUSE_HARD,	/* harder check of CAUSE IE */
};
.Ed
.Pp
All timer values are given in milliseconds.
Note, however, that the actual
resolution of the timers depend on system configuration (see
.Xr timeout 9 ) .
.It Dv NGM_UNI_SET_CONFIG Pq Ic set_config
Change the UNI configuration.
This takes a
.Bd -literal
struct ngm_uni_set_config {
	struct uni_config		config;
	struct ngm_uni_config_mask	mask;
};
struct ngm_uni_config_mask {
	uint32_t	mask;
	uint32_t	popt_mask;
	uint32_t	option_mask;
};
.Ed
.Pp
The fields of the
.Vt ngm_uni_config_mask
specify which configuration parameter to change.
The
.Va mask
field contains bit definitions for all timers, retransmission counters
and the
.Va proto
field,
.Va popt_mask
selects which of the protocol options to change, and
.Va option_mask
specifies which options should be changed.
The following bits are defined:
.Bd -literal
enum uni_config_mask {
	UNICFG_PROTO,
	UNICFG_TIMER301,
	UNICFG_TIMER303,
	UNICFG_INIT303,
	UNICFG_TIMER308,
	UNICFG_INIT308,
	UNICFG_TIMER309,
	UNICFG_TIMER310,
	UNICFG_TIMER313,
	UNICFG_TIMER316,
	UNICFG_INIT316,
	UNICFG_TIMER317,
	UNICFG_TIMER322,
	UNICFG_INIT322,
	UNICFG_TIMER397,
	UNICFG_TIMER398,
	UNICFG_TIMER399,
};
.Ed
.Pp
For
.Va popt_mask
and
.Va option_mask ,
the definitions from
.Vt "enum uni_popt"
and
.Vt "enum uni_option"
should be used.
.It Dv NGM_UNI_ENABLE Pq Ic enable
Create the UNI instance and enable processing.
Before the UNI is enabled parameters cannot be retrieved or set.
.It Dv NGM_UNI_DISABLE Pq Ic disable
Destroy the UNI instance and free all resources.
Note, that connections are not released.
.El
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_atm 4 ,
.Xr ng_sscfu 4 ,
.Xr ng_sscop 4 ,
.Xr ngctl 8
.Sh AUTHORS
The
.Nm uni
netgraph node
and this manual page were written by
.An Harti Brandt Aq Mt harti@FreeBSD.org
.Sh BUGS
.Bl -bullet -compact
.It
LIJ (leaf-initiated-join) is not implemented yet.
.It
GFP (generic functional protocol, Q.2932.1) is not yet implemented.
.It
More testing needed.
.It
PNNI not yet implemented.
.It
Need to implement connection modification and the Q.2931 amendments.
.El