Партнёры:
Хостинг:
ng_uni - netgraph UNI node type
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 started.
The node is shut down either by an NGM_SHUTDOWN message, or when all hooks are disconnected.
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 */
UNIAPI_MAXSIG
};
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:
Each of the signals is followed by a fixed size structure defined in In netnatm/sig/unidef.h .
struct ngm_uni_debug {
uint32_t level[UNI_MAXFACILITY];
};
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)).
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 Vt 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 {
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,
};
For popt_mask and option_mask the definitions from Vt enum uni_popt and Vt enum uni_option should be used.
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