osmo-ttcn3-hacks/library/BSSMAP_Emulation.ttcn

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module BSSMAP_Emulation {
import from SCCP_Emulation all;
import from SCCPasp_Types all;
import from BSSAP_Types all;
import from BSSMAP_Templates all;
import from MGCP_Types all;
import from MGCP_Templates all;
import from IPA_Emulation all;
/* General "base class" component definition, of which specific implementations
* derive themselves by means of the "extends" feature */
type component BSSAP_ConnHdlr {
/* port towards MSC Emulator core / SCCP connection dispatchar */
port BSSAP_Conn_PT BSSAP;
}
/* Auxiliary primitive that can happen on the port between per-connection client and this dispatcher */
type enumerated BSSAP_Conn_Prim {
/* SCCP tell us that connection was released */
MSC_CONN_PRIM_DISC_IND,
/* we tell SCCP to release connection */
MSC_CONN_PRIM_DISC_REQ
}
type record BSSAP_Conn_Req {
SCCP_PAR_Address addr_peer,
SCCP_PAR_Address addr_own,
PDU_BSSAP bssap
}
/* port between individual per-connection components and this dispatcher */
type port BSSAP_Conn_PT message {
inout PDU_BSSAP, BSSAP_Conn_Prim, BSSAP_Conn_Req, MgcpCommand, MgcpResponse;
} with { extension "internal" };
/* represents a single BSSAP connection over SCCP */
type record ConnectionData {
/* reference to the instance of the per-connection component */
BSSAP_ConnHdlr comp_ref,
integer sccp_conn_id,
/* most recent MGCP transaction ID (Used on MSC side) */
MgcpTransId mgcp_trans_id optional,
/* CIC that has been used for voice of this channel (BSC side) */
integer cic optional
}
type component BSSMAP_Emulation_CT {
/* SCCP port on the bottom side, using ASP primitives */
port SCCPasp_PT SCCP;
/* BSSAP port to the per-connection clients */
port BSSAP_Conn_PT CLIENT;
/* MGCP port */
port IPA_MGCP_PT MGCP;
/* use 16 as this is also the number of SCCP connections that SCCP_Emulation can handle */
var ConnectionData ConnectionTable[16];
var charstring g_bssmap_id;
var integer g_next_e1_ts := 1;
};
private function f_conn_id_known(integer sccp_conn_id)
runs on BSSMAP_Emulation_CT return boolean {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].sccp_conn_id == sccp_conn_id){
return true;
}
}
return false;
}
private function f_comp_known(BSSAP_ConnHdlr client)
runs on BSSMAP_Emulation_CT return boolean {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].comp_ref == client) {
return true;
}
}
return false;
}
/* resolve component reference by connection ID */
private function f_comp_by_conn_id(integer sccp_conn_id)
runs on BSSMAP_Emulation_CT return BSSAP_ConnHdlr {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].sccp_conn_id == sccp_conn_id) {
return ConnectionTable[i].comp_ref;
}
}
log("BSSMAP Connection table not found by SCCP Connection ID ", sccp_conn_id);
self.stop;
}
/* resolve component reference by CIC */
private function f_comp_by_mgcp_tid(MgcpTransId tid)
runs on BSSMAP_Emulation_CT return BSSAP_ConnHdlr {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].mgcp_trans_id == tid) {
return ConnectionTable[i].comp_ref;
}
}
log("BSSMAP Connection table not found by MGCP Transaction ID ", tid);
self.stop;
}
private function f_comp_store_mgcp_tid(BSSAP_ConnHdlr client, MgcpTransId tid)
runs on BSSMAP_Emulation_CT {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].comp_ref == client) {
ConnectionTable[i].mgcp_trans_id := tid;
return;
}
}
log("BSSMAP Connection table not found by component ", client);
self.stop;
}
private function f_comp_by_cic(integer cic)
runs on BSSMAP_Emulation_CT return BSSAP_ConnHdlr {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].cic == cic) {
return ConnectionTable[i].comp_ref;
}
}
log("BSSMAP Connection table not found by CIC ", cic);
self.stop;
}
private function f_comp_store_cic(BSSAP_ConnHdlr client, integer cic)
runs on BSSMAP_Emulation_CT {
var integer i;
for (i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].comp_ref == client) {
ConnectionTable[i].cic := cic;
return;
}
}
log("BSSMAP Connection table not found by component ", client);
}
/* resolve connection ID by component reference */
private function f_conn_id_by_comp(BSSAP_ConnHdlr client)
runs on BSSMAP_Emulation_CT return integer {
for (var integer i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].comp_ref == client) {
return ConnectionTable[i].sccp_conn_id;
}
}
log("BSSMAP Connection table not found by component ", client);
self.stop;
}
private function f_gen_conn_id()
runs on BSSMAP_Emulation_CT return integer {
var integer conn_id;
do {
conn_id := float2int(rnd()*SCCP_Emulation.tsp_max_ConnectionId);
} while (f_conn_id_known(conn_id) == true);
return conn_id;
}
private function f_conn_table_init()
runs on BSSMAP_Emulation_CT {
for (var integer i := 0; i < sizeof(ConnectionTable); i := i+1) {
ConnectionTable[i].comp_ref := null;
ConnectionTable[i].sccp_conn_id := -1;
ConnectionTable[i].mgcp_trans_id := omit;
ConnectionTable[i].cic := omit;
}
}
private function f_conn_table_add(BSSAP_ConnHdlr comp_ref, integer sccp_conn_id)
runs on BSSMAP_Emulation_CT {
for (var integer i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].sccp_conn_id == -1) {
ConnectionTable[i].comp_ref := comp_ref;
ConnectionTable[i].sccp_conn_id := sccp_conn_id;
log("Added conn table entry ", i, comp_ref, sccp_conn_id);
return;
}
}
log("BSSMAP Connection table full!");
self.stop;
}
private function f_conn_table_del(integer sccp_conn_id)
runs on BSSMAP_Emulation_CT {
for (var integer i := 0; i < sizeof(ConnectionTable); i := i+1) {
if (ConnectionTable[i].sccp_conn_id == sccp_conn_id) {
log("Deleted conn table entry ", i,
ConnectionTable[i].comp_ref, sccp_conn_id);
ConnectionTable[i].sccp_conn_id := -1;
ConnectionTable[i].comp_ref := null;
}
}
log("BSSMAP Connection table attempt to delete non-existant ", sccp_conn_id);
self.stop;
}
/* handle (optional) userData portion of various primitives and dispatch it to the client */
private function f_handle_userData(BSSAP_ConnHdlr client, octetstring userdata)
runs on BSSMAP_Emulation_CT {
/* decode + send decoded BSSAP to client */
var PDU_BSSAP bssap := dec_PDU_BSSAP(valueof(userdata));
/* BSC Side: If this is an assignment command, store CIC */
if (ischosen(bssap.pdu.bssmap.assignmentRequest) and
ispresent(bssap.pdu.bssmap.assignmentRequest.circuitIdentityCode)) {
var BSSMAP_IE_CircuitIdentityCode cic_ie :=
bssap.pdu.bssmap.assignmentRequest.circuitIdentityCode;
var integer cic := (oct2int(cic_ie.cicHigh) * 256) + oct2int(cic_ie.cicLow);
f_comp_store_cic(client, cic);
}
CLIENT.send(bssap) to client;
}
/* call-back type, to be provided by specific implementation; called when new SCCP connection
* arrives */
type function BssmapCreateCallback(ASP_SCCP_N_CONNECT_ind conn_ind, charstring id)
runs on BSSMAP_Emulation_CT return BSSAP_ConnHdlr;
type function BssmapUnitdataCallback(PDU_BSSAP bssap)
runs on BSSMAP_Emulation_CT return template PDU_BSSAP;
type record BssmapOps {
BssmapCreateCallback create_cb,
BssmapUnitdataCallback unitdata_cb
}
function main(BssmapOps ops, charstring id) runs on BSSMAP_Emulation_CT {
g_bssmap_id := id;
f_conn_table_init();
while (true) {
var ASP_SCCP_N_UNITDATA_ind ud_ind;
var ASP_SCCP_N_CONNECT_ind conn_ind;
var ASP_SCCP_N_CONNECT_cfm conn_cfm;
var ASP_SCCP_N_DATA_ind data_ind;
var ASP_SCCP_N_DISCONNECT_ind disc_ind;
var BSSAP_Conn_Req creq;
var BSSAP_ConnHdlr vc_conn;
var PDU_BSSAP bssap;
var MgcpCommand mgcp_req;
var MgcpResponse mgcp_resp;
alt {
/* SCCP -> Client: UNIT-DATA (connectionless SCCP) from a BSC */
[] SCCP.receive(ASP_SCCP_N_UNITDATA_ind:?) -> value ud_ind {
/* Connectionless Procedures like RESET */
var template PDU_BSSAP resp;
bssap := dec_PDU_BSSAP(ud_ind.userData);
resp := ops.unitdata_cb.apply(bssap);
if (isvalue(resp)) {
var octetstring resp_ud := enc_PDU_BSSAP(valueof(resp));
SCCP.send(t_ASP_N_UNITDATA_req(ud_ind.callingAddress,
ud_ind.calledAddress, omit,
omit, resp_ud, omit));
}
}
/* SCCP -> Client: new connection from BSC */
[] SCCP.receive(ASP_SCCP_N_CONNECT_ind:?) -> value conn_ind {
vc_conn := ops.create_cb.apply(conn_ind, id);
/* store mapping between client components and SCCP connectionId */
f_conn_table_add(vc_conn, conn_ind.connectionId);
/* handle user payload */
f_handle_userData(vc_conn, conn_ind.userData);
/* confirm connection establishment */
SCCP.send(t_ASP_N_CONNECT_res(omit, omit, omit, omit, conn_ind.connectionId, omit));
}
/* SCCP -> Client: connection-oriented data in existing connection */
[] SCCP.receive(ASP_SCCP_N_DATA_ind:?) -> value data_ind {
vc_conn := f_comp_by_conn_id(data_ind.connectionId);
if (ispresent(data_ind.userData)) {
f_handle_userData(vc_conn, data_ind.userData);
}
}
/* SCCP -> Client: disconnect of an existing connection */
[] SCCP.receive(ASP_SCCP_N_DISCONNECT_ind:?) -> value disc_ind {
vc_conn := f_comp_by_conn_id(disc_ind.connectionId);
if (ispresent(disc_ind.userData)) {
f_handle_userData(vc_conn, disc_ind.userData);
}
/* notify client about termination */
var BSSAP_Conn_Prim prim := MSC_CONN_PRIM_DISC_IND;
CLIENT.send(prim) to vc_conn;
f_conn_table_del(disc_ind.connectionId);
/* TOOD: return confirm to other side? */
}
/* SCCP -> Client: connection confirm for outbound connection */
[] SCCP.receive(ASP_SCCP_N_CONNECT_cfm:?) -> value conn_cfm {
/* handle user payload */
if (ispresent(conn_cfm.userData)) {
f_handle_userData(vc_conn, conn_cfm.userData);
}
}
/* Disconnect request client -> SCCP */
[] CLIENT.receive(BSSAP_Conn_Prim:MSC_CONN_PRIM_DISC_REQ) -> sender vc_conn {
var integer conn_id := f_conn_id_by_comp(vc_conn);
SCCP.send(t_ASP_N_DISCONNECT_req(omit, 0, omit, conn_id, omit));
f_conn_table_del(conn_id);
}
/* BSSAP from client -> SCCP */
[] CLIENT.receive(BSSAP_Conn_Req:?) -> value creq sender vc_conn {
var integer conn_id;
/* encode + send to dispatcher */
var octetstring userdata := enc_PDU_BSSAP(creq.bssap);
if (f_comp_known(vc_conn) == false) {
/* unknown client, create new connection */
conn_id := f_gen_conn_id();
/* store mapping between client components and SCCP connectionId */
f_conn_table_add(vc_conn, conn_id);
SCCP.send(t_ASP_N_CONNECT_req(creq.addr_peer, creq.addr_own, omit, omit,
userdata, conn_id, omit));
} else {
/* known client, send via existing connection */
conn_id := f_conn_id_by_comp(vc_conn);
SCCP.send(t_ASP_N_DATA_req(userdata, conn_id, omit));
}
}
[] CLIENT.receive(PDU_BSSAP:?) -> value bssap sender vc_conn {
var integer conn_id := f_conn_id_by_comp(vc_conn);
/* encode + send it to dispatcher */
var octetstring userdata := enc_PDU_BSSAP(bssap);
SCCP.send(t_ASP_N_DATA_req(userdata, conn_id, omit));
}
/* Handling of MGCP in IPA SCCPLite case. This predates 3GPP AoIP
* and uses a MGCP session in parallel to BSSAP. BSSAP uses CIC
* as usual, and MGCP uses "CIC@mgw" endpoint naming, where CIC
* is printed as hex string, e.g. a@mgw for CIC 10 */
/* CLIENT -> MGCP */
[] CLIENT.receive(MgcpCommand:?) -> value mgcp_req sender vc_conn {
/* MGCP request from Handler (we're MSC) */
/* store the transaction ID we've seen */
f_comp_store_mgcp_tid(vc_conn, mgcp_req.line.trans_id);
/* simply forward any MGCP from the client to the port */
MGCP.send(mgcp_req);
}
[] CLIENT.receive(MgcpResponse:?) -> value mgcp_resp sender vc_conn {
/* MGCP response from Handler (we're BSC/MGW) */
/* simply forward any MGCP from the client to the port */
MGCP.send(mgcp_resp);
}
/* MGCP -> CLIENT */
[] MGCP.receive(MgcpCommand:?) -> value mgcp_req {
/* MGCP request from network side (we're BSC/MGW) */
/* Extract CIC from local part of endpoint name */
var integer cic := f_mgcp_ep_extract_cic(mgcp_req.line.ep);
/* Resolve the vc_conn by the CIC */
vc_conn := f_comp_by_cic(cic);
CLIENT.send(mgcp_req) to vc_conn;
}
[] MGCP.receive(MgcpResponse:?) -> value mgcp_resp {
/* MGCP response from network side (we're MSC) */
/* Resolve the vc_conn by the transaction ID */
vc_conn := f_comp_by_mgcp_tid(mgcp_resp.line.trans_id);
CLIENT.send(mgcp_resp) to vc_conn;
}
}
}
}
private function f_mgcp_ep_extract_cic(charstring inp) return integer {
var charstring local_part := regexp(inp, "(*)@*", 0);
return hex2int(str2hex(local_part));
}
}