| /* GPRS-NS Emulation in TTCN-3 |
| * (C) 2018-2020 Harald Welte <laforge@gnumonks.org> |
| * contributions by sysmocom - s.f.m.c. GmbH |
| * All rights reserved. |
| * |
| * Released under the terms of GNU General Public License, Version 2 or |
| * (at your option) any later version. |
| * |
| * SPDX-License-Identifier: GPL-2.0-or-later |
| */ |
| |
| module NS_Emulation { |
| import from NS_Types all; |
| import from BSSGP_Types all; |
| import from Osmocom_Gb_Types all; |
| import from NS_Provider_IPL4 all; |
| import from IPL4asp_Types all; |
| import from PCUIF_Types all; |
| |
| type record NsUnitdataRequest { |
| BssgpBvci bvci, |
| Nsei nsei, |
| octetstring sdu optional, |
| PDU_BSSGP bssgp optional |
| } |
| |
| template NsUnitdataRequest t_NsUdReq(template Nsei nsei, template BssgpBvci bvci, template octetstring sdu, |
| template PDU_BSSGP bssgp) := { |
| bvci := bvci, |
| nsei := nsei, |
| sdu := sdu, |
| bssgp := bssgp |
| } |
| |
| type record NsUnitdataIndication { |
| BssgpBvci bvci, |
| Nsei nsei, |
| octetstring sdu optional, |
| PDU_BSSGP bssgp optional |
| } |
| |
| template NsUnitdataIndication t_NsUdInd(Nsei nsei, BssgpBvci bvci, octetstring sdu) := { |
| bvci := bvci, |
| nsei := nsei, |
| sdu := sdu, |
| bssgp := dec_PDU_BSSGP(sdu) |
| } |
| |
| type record NsStatusIndication { |
| Nsei nsei, |
| Nsvci nsvci, |
| NseState old_state, |
| NseState new_state |
| } |
| |
| template NsStatusIndication t_NsStsInd(Nsei nsei, Nsvci nsvci, NseState old_state, NseState state) := { |
| nsei := nsei, |
| nsvci := nsvci, |
| old_state := old_state, |
| new_state := state |
| } |
| |
| type enumerated NseState { |
| NSE_S_DEAD_BLOCKED, |
| NSE_S_WAIT_RESET, |
| NSE_S_ALIVE_BLOCKED, |
| NSE_S_ALIVE_UNBLOCKED |
| } |
| |
| /* port from our (internal) point of view */ |
| type port NS_SP_PT message { |
| in NsUnitdataRequest; |
| out NsUnitdataIndication, |
| NsStatusIndication; |
| } with { extension "internal" }; |
| |
| /* port from the user point of view */ |
| type port NS_PT message { |
| in ASP_Event, |
| NsStatusIndication, |
| NsUnitdataIndication; |
| out NsUnitdataRequest; |
| } with { extension "internal" }; |
| |
| function NSStart(NSConfiguration init_config) runs on NS_CT { |
| config := init_config; |
| f_init(); |
| f_ScanEvents(); |
| } |
| |
| private function f_init() runs on NS_CT { |
| var Result res; |
| |
| /* Connect the UDP socket */ |
| vc_NSP_IP := NS_Provider_IPL4_CT.create; |
| connect(self:NSCP, vc_NSP_IP:NSE); |
| vc_NSP_IP.start(NS_Provider_IPL4.main(config)); |
| |
| f_change_state(NSE_S_DEAD_BLOCKED); |
| /* Send the first NS-ALIVE to test the connection */ |
| if (not config.role_sgsn) { |
| f_sendReset(); |
| } |
| } |
| |
| type component NS_Provider_CT { |
| /* upper port, facing to NS_Emulation:NSCP */ |
| port NS_PROVIDER_PT NSE; |
| /* lower layer ports (UDP/IP, Frame Relay) are added in derived components */ |
| }; |
| |
| /* port between NS_Provider and NS_CT */ |
| type port NS_PROVIDER_PT message { |
| inout PDU_NS; |
| } with { extension "internal" }; |
| |
| type component NS_CT { |
| /* UDP port towards the bottom (IUT) */ |
| port NS_PROVIDER_PT NSCP; |
| var NS_Provider_IPL4_CT vc_NSP_IP; |
| |
| /* NS-User SAP towards the user */ |
| port NS_SP_PT NS_SP; |
| |
| var NSConfiguration config; |
| |
| var NseState g_state := NSE_S_DEAD_BLOCKED; |
| |
| timer Tns_alive := 3.0; |
| timer Tns_test := 10.0; |
| timer Tns_block := 10.0; |
| } |
| |
| type record NSConfiguration { |
| PCUIF_AddrType remote_proto, |
| PortNumber local_udp_port, |
| charstring local_ip, |
| PortNumber remote_udp_port, |
| charstring remote_ip, |
| Nsvci nsvci, |
| Nsvci nsei, |
| boolean role_sgsn, |
| boolean handle_sns |
| } |
| |
| private function f_change_state(NseState new_state) runs on NS_CT { |
| var NseState old_state := g_state; |
| g_state := new_state; |
| log("NS State Transition: ", old_state, " -> ", new_state); |
| NS_SP.send(t_NsStsInd(config.nsei, config.nsvci, old_state, new_state)); |
| } |
| |
| private function f_sendReset() runs on NS_CT { |
| NSCP.send(ts_NS_RESET(NS_CAUSE_OM_INTERVENTION, config.nsvci, config.nsei)); |
| g_state := NSE_S_WAIT_RESET; |
| } |
| |
| private function f_sendAlive() runs on NS_CT { |
| NSCP.send(t_NS_ALIVE); |
| Tns_alive.start; |
| } |
| |
| private function f_sendUnblock() runs on NS_CT { |
| NSCP.send(t_NS_UNBLOCK); |
| Tns_block.start; |
| } |
| |
| private function f_sendBlock(NsCause cause) runs on NS_CT { |
| NSCP.send(ts_NS_BLOCK(cause, config.nsvci)); |
| Tns_block.start; |
| } |
| |
| altstep as_allstate() runs on NS_CT { |
| var PDU_NS rf; |
| var ASP_Event evt; |
| |
| /* transition to DEAD if t_alive times out */ |
| [Tns_alive.running] Tns_alive.timeout { |
| log("Tns-aeive expired: changing to DEAD_BLOCKED + starting Tns-test"); |
| f_change_state(NSE_S_DEAD_BLOCKED); |
| Tns_test.start; |
| } |
| |
| [Tns_test.running] Tns_test.timeout { |
| log("Tns-test expired: sending NS-ALIVE"); |
| f_sendAlive(); |
| } |
| |
| /* Stop t_alive when receiving ALIVE-ACK */ |
| [] NSCP.receive(t_NS_ALIVE_ACK) { |
| log("NS-ALIVE-ACK received: stopping Tns-alive; starting Tns-test"); |
| Tns_alive.stop; |
| Tns_test.start; |
| } |
| |
| /* respond to NS-ALIVE with NS-ALIVE-ACK */ |
| [] NSCP.receive(t_NS_ALIVE) { |
| NSCP.send(t_NS_ALIVE_ACK); |
| } |
| |
| /* Respond to BLOCK for wrong NSVCI */ |
| [] NSCP.receive(tr_NS_BLOCK(?, ?)) -> value rf { |
| log("Rx NS-BLOCK for unknown NSVCI"); |
| /* FIXME */ |
| } |
| |
| /* Respond to RESET with correct NSEI/NSVCI */ |
| [] NSCP.receive(tr_NS_RESET(?, config.nsvci, config.nsei)) -> value rf { |
| f_change_state(NSE_S_ALIVE_BLOCKED); |
| NSCP.send(ts_NS_RESET_ACK(config.nsvci, config.nsei)); |
| } |
| |
| /* Respond to RESET with wrong NSEI/NSVCI */ |
| [] NSCP.receive(tr_NS_RESET(?, ?, ?)) -> value rf { |
| log("Rx NS-RESET for unknown NSEI/NSVCI"); |
| /* FIXME */ |
| } |
| |
| [config.role_sgsn and config.handle_sns] as_sns_sgsn(); |
| |
| /* default case of handling unknown PDUs */ |
| [] NSCP.receive(PDU_NS: ?) -> value rf { |
| log("Rx Unexpected NS PDU ", rf," in state ", g_state); |
| NSCP.send(ts_NS_STATUS(NS_CAUSE_PDU_NOT_COMPATIBLE_WITH_PROTOCOL_STATE, rf)); |
| } |
| } |
| |
| /* simple IP Sub-Network Service responder for the SGSN side. This is not a full implementation |
| * of the protocol, merely sufficient to make the PCU/BSS side happy to proceed */ |
| altstep as_sns_sgsn() runs on NS_CT { |
| var PDU_NS rf; |
| [] NSCP.receive(tr_SNS_SIZE(config.nsei)) -> value rf { |
| /* blindly acknowledge whatever the PCU sends */ |
| NSCP.send(ts_SNS_SIZE_ACK(config.nsei, omit)); |
| } |
| [] NSCP.receive(tr_SNS_SIZE(?)) { |
| setverdict(fail, "SNS-SIZE from unexpected NSEI"); |
| self.stop; |
| } |
| [] NSCP.receive(tr_SNS_CONFIG(config.nsei, true, |
| {tr_SNS_IPv4(config.remote_ip, config.remote_udp_port)})) -> value rf { |
| /* blindly acknowledge whatever the PCU sends */ |
| NSCP.send(ts_SNS_CONFIG_ACK(config.nsei, omit)); |
| /* send a SNS-CONFIG in response and expect a SNS-CONFIG-ACK */ |
| var IP4_Elements v4 := { valueof(ts_SNS_IPv4(config.local_ip, config.local_udp_port)) }; |
| NSCP.send(ts_SNS_CONFIG(config.nsei, true, v4)); |
| alt { |
| [] NSCP.receive(tr_SNS_CONFIG_ACK(config.nsei, omit)) { |
| /* success */ |
| } |
| [] NSCP.receive(tr_SNS_CONFIG_ACK(config.nsei, ?)) { |
| setverdict(fail, "Unexpected SNS-CONFIG-NACK"); |
| self.stop; |
| } |
| } |
| } |
| [] NSCP.receive(tr_SNS_CONFIG(config.nsei, false, ?)) { /* ignore */} |
| [] NSCP.receive(tr_SNS_CONFIG(config.nsei, true, ?)) { |
| setverdict(fail, "Unexpected SNS-CONFIG content"); |
| self.stop; |
| } |
| [] NSCP.receive(tr_SNS_CONFIG(?, ?, ?)) { |
| setverdict(fail, "SNS-CONFIG from unexpected NSEI"); |
| self.stop; |
| } |
| } |
| |
| private function f_ScanEvents() runs on NS_CT { |
| var NsUnitdataRequest ud_req; |
| var PDU_NS rf; |
| var default d; |
| |
| d := activate(as_allstate()); |
| |
| while (true) { |
| if (g_state == NSE_S_DEAD_BLOCKED) { |
| alt { |
| [false] any timer.timeout {} |
| } |
| } else if (g_state == NSE_S_WAIT_RESET) { |
| alt { |
| [] NSCP.receive(tr_NS_RESET_ACK(config.nsvci, config.nsei)) -> value rf { |
| f_change_state(NSE_S_ALIVE_BLOCKED); |
| f_sendAlive(); |
| f_sendUnblock(); |
| } |
| } |
| } else if (g_state == NSE_S_ALIVE_BLOCKED) { |
| alt { |
| /* bogus block, just respond with ACK */ |
| [] NSCP.receive(tr_NS_BLOCK(?, config.nsvci)) -> value rf { |
| NSCP.send(ts_NS_BLOCK_ACK(config.nsvci)); |
| } |
| /* Respond to UNBLOCK with UNBLOCK-ACK + change state */ |
| [] NSCP.receive(t_NS_UNBLOCK) -> value rf { |
| NSCP.send(t_NS_UNBLOCK_ACK); |
| Tns_block.stop; |
| f_change_state(NSE_S_ALIVE_UNBLOCKED); |
| } |
| [] NSCP.receive(t_NS_UNBLOCK_ACK) -> value rf { |
| Tns_block.stop; |
| f_change_state(NSE_S_ALIVE_UNBLOCKED); |
| } |
| [] Tns_block.timeout { |
| /* repeat unblock transmission */ |
| f_sendUnblock(); |
| } |
| } |
| } else if (g_state == NSE_S_ALIVE_UNBLOCKED) { |
| alt { |
| /* bogus unblock, just respond with ACK */ |
| [] NSCP.receive(t_NS_UNBLOCK) -> value rf { |
| NSCP.send(t_NS_UNBLOCK_ACK); |
| } |
| /* Respond to BLOCK with BLOCK-ACK + change state */ |
| [] NSCP.receive(tr_NS_BLOCK(?, config.nsvci)) -> value rf { |
| NSCP.send(ts_NS_BLOCK_ACK(config.nsvci)); |
| Tns_block.stop; |
| f_change_state(NSE_S_ALIVE_BLOCKED); |
| } |
| [] NSCP.receive(tr_NS_BLOCK_ACK(config.nsvci)) -> value rf { |
| Tns_block.stop; |
| } |
| /* NS-UNITDATA PDU from network to NS-UNITDATA.ind to user */ |
| [] NSCP.receive(tr_NS_UNITDATA(?, ?, ?)) -> value rf { |
| NS_SP.send(t_NsUdInd(config.nsei, |
| oct2int(rf.pDU_NS_Unitdata.bVCI), |
| rf.pDU_NS_Unitdata.nS_SDU)); |
| } |
| /* NS-UNITDATA.req from user to NS-UNITDATA PDU on network */ |
| [] NS_SP.receive(t_NsUdReq(config.nsei, ?, ?, omit)) -> value ud_req { |
| /* using raw octetstring PDU */ |
| NSCP.send(ts_NS_UNITDATA(t_SduCtrlB, ud_req.bvci, ud_req.sdu)); |
| } |
| [] NS_SP.receive(t_NsUdReq(config.nsei, ?, omit, ?)) -> value ud_req { |
| /* using decoded BSSGP PDU that we need to encode first */ |
| var octetstring enc := enc_PDU_BSSGP(ud_req.bssgp); |
| NSCP.send(ts_NS_UNITDATA(t_SduCtrlB, ud_req.bvci, enc)); |
| } |
| } |
| } |
| |
| } /* while */ |
| //deactivate(d); |
| } |
| } |