unisap(3)

NAME

unimsg, unisve_check_addr, unisve_check_selector,

unisve_check_blli_id2,
unisve_check_blli_id3, unisve_check_bhli, unisve_check_sap, unisve_overlap_addr, unisve_overlap_selector,

unisve_overlap_blli_id2,
unisve_overlap_blli_id3, unisve_overlap_bhli,

unisve_overlap_sap,
unisve_is_catchall, unisve_match - ATM signalling library

ATM SAP handling

LIBRARY

Begemot ATM signalling library (libunimsg, -lunimsg)

SYNOPSIS

#include <uni4/unisap.h>
int
unisve_check_addr(const struct unisve_addr *sve);
int
unisve_check_selector(const struct unisve_selector *sve);
int
unisve_check_blli_id2(const struct unisve_blli_id2 *sve);
int
unisve_check_blli_id3(const struct unisve_blli_id3 *sve);
int
unisve_check_bhli(const struct unisve_bhli *sve);
int
unisve_check_sap(const struct uni_sap *sve);
int
unisve_overlap_addr(const struct unisve_addr *sve1,
        const struct unisve_addr *sve2);
int
unisve_overlap_selector(const struct unisve_selector *sve1,
        const struct unisve_selector *sve2);
int
unisve_overlap_blli_id2(const struct unisve_blli_id2 *sve1,
        const struct unisve_blli_id2 *sve2);
int
unisve_overlap_blli_id3(const struct unisve_blli_id3 *sve1,
        const struct unisve_blli_id3 *sve2);
int
unisve_overlap_bhli(const struct unisve_bhli *sve1,
        const struct unisve_bhli *sve2);
int
unisve_overlap_sap(const struct uni_sap *sap1,
        const struct uni_sap *sap2);
int
unisve_is_catchall(const struct uni_sap *sap);
int
unisve_match(const struct uni_sap *sap,
        const struct uni_ie_called *called,
        const  struct  uni_ie_blli   *blli,   const   struct
uni_ie_bhli *bhli);

DESCRIPTION

The unimsg library contains functions to handle Service Ac

cess Points
(SAP) and SAP Vector Elements (SVE) as specified in the ATM

Forum ATM API
Semantic Description. SAPs are the analog of TCP and UDP

ports in the
ATM world. As usually in ATM they are a couple of orders of

magnitude
more complex as their Internet equivalent. See the ATM Forum

document for
a description.

A SAP is a data structure:

struct uni_sap {

struct unisve_addr addr;
struct unisve_selector selector;
struct unisve_blli_id2 blli_id2;
struct unisve_blli_id3 blli_id3;
struct unisve_bhli bhli;

};

that consists of 5 elements matching different information

elements in
the SETUP message. Each of these elements has a tag that de

fines how the
SVE is to be matched with the information element. The tag

is one of

UNISVE_ABSENT The information element has to absent

from the SETUP

message.

UNISVE_PRESENT The information element has to be pre

sent in the

SETUP message and must match the SVE.

UNISVE_ANY The information element may be absent

from the SETUP

message or may have any value.

The called address is matched by a

struct unisve_addr {

enum unisve_tag tag;
enum uni_addr_type type;/* type of address */
enum uni_addr_plan plan;/* addressing plan */
u_int32_t len; /* length of address

*/
u_char addr[UNI_ADDR_MAXLEN];

};

Here type is the type of address and plan is the address

plan. len is
the length of the address (for ATME addresses not counting

the selector
byte) and addr is the address itself.

In case of ATME addresses the selector byte is matched by a

struct unisve_selector {

enum unisve_tag tag;
u_int8_t selector;

};

Here selector is the selector byte that must match the 20th

byte of the
ATME calling address from the SETUP message.

The BLLI information element is matched by two SVEs: one for

layer 2
options and one for layer 3 options. The layer 2 SVE is:

struct unisve_blli_id2 {

enum unisve_tag tag;
u_int8_t proto:5;/* the protocol */
u_int8_t user:7; /* user specific pro

tocol */

};

Where the user fields is matched only if the proto field

specifies
UNI_BLLI_L2_USER. The layer 3 SVE is:

struct unisve_blli_id3 {

enum unisve_tag tag;
u_int8_t proto:5;/* L3 protocol */
u_int8_t user:7; /* user specific pro

tocol */
u_int8_t ipi:8; /* ISO/IEC TR 9557 IPI

*/
u_int32_t oui:24; /* IEEE 802.1 OUI */
u_int32_t pid:16; /* IEEE 802.1 PID */
u_int32_t noipi; /* ISO/IEC TR 9557 per

frame */

};

For the exact rules how matching occures refer to the source

code or the
ATM Forum document.

Finally the BHLI information element is matched with a

struct unisve_bhli {

enum unisve_tag tag;
enum uni_bhli type; /* type of info */
u_int32_t len; /* length of info */
u_int8_t info[8];/* info itself */

};

For each SVE type there is a function that checks whether

the SVE is correct specified. The functions unisve_check_addr(), unisve_check_selector(), unisve_check_blli_id2(), unisve_check_blli_id3(), and unisve_check_bhli() return one

of the following error codes:

enum {

UNISVE_OK = 0,
UNISVE_ERROR_BAD_TAG,
UNISVE_ERROR_TYPE_PLAN_CONFLICT,
UNISVE_ERROR_ADDR_SEL_CONFLICT,
UNISVE_ERROR_ADDR_LEN,
UNISVE_ERROR_BAD_ADDR_TYPE,
UNISVE_ERROR_BAD_BHLI_TYPE,
UNISVE_ERROR_BAD_BHLI_LEN,

};

A code of UNISVE_OK means that the SVE has no error. The

function
unisve_check_sap() checks a complete SAP and returns one of

the above
codes.

There is a definition UNISVE_ERRSTR that evaluates to a com

ma separated
list of strings that can be used to initializes an array of

char pointers
to map the error codes into human readable strings.

The ATM Forum document defines the concept of overlaping

SAPs. This basically means, that an incoming SETUP could match more than

one SAP (and
more than one application) to receive the SETUP. For each

SVE type there
is a function that checks whether two SVEs overlap and there

is a function that checks whether two SAPs overlap. The functions
unisve_overlap_addr(), unisve_overlap_selector(), unisve_overlap_blli_id2(), unisve_overlap_blli_id3(), unisve_overlap_bhli(), and unisve_overlap_sap() return 1 if

the SVEs or
SAPs overlap and 0 if they do not. They assume, that the

SAPs are correct.

The ATM Forum document specifies a catch-all SAP. The func

tion
unisve_is_catchall() returns 1 if the SAP is the catch-all

SAP and 0 otherwise.

Finally the function unisve_match() is used to match a SAP

against the
information elements from a SETUP message. It returns 1 if

they match
and 0 otherwise.

SEE ALSO

libunimsg(3)

AUTHORS

Hartmut Brandt <harti@freebsd.org>

BSD May 23, 2005

BSD