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     ng_uni — netgraph UNI node type


     #include <netnatm/msg/unistruct.h>
     #include <netnatm/sig/unidef.h>
     #include <netgraph/atm/ng_uni.h>


     The uni netgraph node type implements ATM Forum signalling 4.0.

     After creation of the node, the UNI instance must be created by sending
     an “enable” message to the node.  If the node is enabled, the UNI
     parameters can be retrieved and modified, and the protocol can be

     The node is shut down either by an NGM_SHUTDOWN message, or when all
     hooks are disconnected.


     Each uni node has three hooks with fixed names:

     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 ng_sscfu(4) at this hook.

     upper  This hook is the “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 ng_ccatm(4) or a switch CAC should be stacked at this
            interface.  The message format at the upper hook is described
            below.  Because netgraph(4) is functional, it makes sometimes
            sense to switch this hook to queueing mode from the peer node upon

     The upper interface of the 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
     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.

     The upper interface uses the following structure:

     struct uni_arg {
             uint32_t        sig;
             uint32_t        cookie;
             u_char          data[];
     The sig field contains the actual signal that is sent from the user to
     UNI or from UNI to the user.  The 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 cookie field is followed by the actual data for
     the signal.

     The signal is one of the following:

     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 */


     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:

             This is the error response, mentioned earlier.  It carries an
             error code or zero, if the signal was accepted by the stack.

             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.

             A call instance has been destroyed and all resources have been

             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.

             A party has been destroyed and all resources have been freed.

             This requests the stack to destroy the call instance and free all
             its resources, without sending any messages to the network.

             This is not a signal, but rather a definition to get the number
             of defined signals.

     Each of the signals is followed by a fixed size structure defined in


     The uni node understands the standard control messages, plus the

             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

             struct ngm_uni_debug {
                     uint32_t        level[UNI_MAXFACILITY];

             Get debugging facility levels.  This returns an ngm_uni_debug

             Retrieve the current configuration of the UNI instance.  This
             message returns a uni_config structure:

             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 */

             The field proto specifies one of the following protocols:

             enum uni_proto {
                     UNIPROTO_UNI40U,        /* UNI4.0 user side */
                     UNIPROTO_UNI40N,        /* UNI4.0 network side */
                     UNIPROTO_PNNI10,        /* PNNI1.0 */

             Some protocols may have options which can be set in popt:

             enum uni_popt {
                     UNIPROTO_GFP,           /* enable GFP */

             The option field controls parsing and checking of messages:

             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 */

             All timer values are given in milliseconds.  Note, however, that
             the actual resolution of the timers depend on system
             configuration (see timeout(9)).

             Change the UNI configuration.  This takes a

             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;

             The fields of the ngm_uni_config_mask specify which configuration
             parameter to change.  The mask field contains bit definitions for
             all timers, retransmission counters and the proto field,
             popt_mask selects which of the protocol options to change, and
             option_mask specifies which options should be changed.  The
             following bits are defined:

             enum uni_config_mask {

             For popt_mask and option_mask, the definitions from enum uni_popt
             and enum uni_option should be used.

             Create the UNI instance and enable processing.  Before the UNI is
             enabled parameters cannot be retrieved or set.

             Destroy the UNI instance and free all resources.  Note, that
             connections are not released.


     netgraph(4), ng_atm(4), ng_sscfu(4), ng_sscop(4), ngctl(8)


     The uni netgraph node and this manual page were written by Harti Brandt


     ·   LIJ (leaf-initiated-join) is not implemented yet.
     ·   GFP (generic functional protocol, Q.2932.1) is not yet implemented.
     ·   More testing needed.
     ·   PNNI not yet implemented.
     ·   Need to implement connection modification and the Q.2931 amendments.