Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 1 | /* Component implementing a IMS server towards Asterisk's IMS UE |
| 2 | * (C) 2024 by sysmocom - s.f.m.c. GmbH <info@sysmocom.de> |
| 3 | * Author: Pau Espin Pedrol <pespin@sysmocom.de> |
| 4 | * All rights reserved. |
| 5 | * |
| 6 | * Released under the terms of GNU General Public License, Version 2 or |
| 7 | * (at your option) any later version. |
| 8 | * |
| 9 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 10 | */ |
| 11 | module IMS_ConnectionHandler { |
| 12 | |
| 13 | import from TCCOpenSecurity_Functions all; |
| 14 | import from General_Types all; |
| 15 | import from Osmocom_Types all; |
| 16 | import from Native_Functions all; |
| 17 | import from Misc_Helpers all; |
| 18 | |
| 19 | import from SDP_Types all; |
| 20 | import from SDP_Templates all; |
| 21 | |
| 22 | import from SIP_Emulation all; |
| 23 | import from SIPmsg_Types all; |
| 24 | import from SIP_Templates all; |
| 25 | |
Pau Espin Pedrol | a2812ec | 2024-05-10 20:30:44 +0200 | [diff] [blame] | 26 | const char c_sip_server_name := "osmo-ttcn3-hacks/0.23"; |
| 27 | |
| 28 | |
Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 29 | type port IMSCoord_PT message |
| 30 | { |
| 31 | inout charstring; |
| 32 | } with { extension "internal" }; |
| 33 | |
| 34 | const charstring IMS_COORD_CMD_REGISTERED := "COORD_CMD_REGISTERED"; |
| 35 | |
| 36 | type component IMS_ConnHdlr extends SIP_ConnHdlr { |
| 37 | var charstring g_name; |
| 38 | var IMS_ConnHdlrPars g_pars; |
| 39 | timer g_Tguard; |
| 40 | var PDU_SIP_Request g_rx_sip_req; |
| 41 | var PDU_SIP_Response g_rx_sip_resp; |
| 42 | |
| 43 | port IMSCoord_PT COORD; |
| 44 | } |
| 45 | type record of IMS_ConnHdlr IMS_ConnHdlrList; |
| 46 | |
| 47 | type record IMS_ConnHdlrPars { |
| 48 | float t_guard, |
Pau Espin Pedrol | a2812ec | 2024-05-10 20:30:44 +0200 | [diff] [blame] | 49 | charstring realm, |
| 50 | charstring local_sip_host, |
| 51 | uint16_t local_sip_port, |
| 52 | charstring remote_sip_host optional, |
| 53 | uint16_t remote_sip_port optional, |
Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 54 | charstring user, |
| 55 | charstring display_name, |
| 56 | charstring password, |
Pau Espin Pedrol | a2812ec | 2024-05-10 20:30:44 +0200 | [diff] [blame] | 57 | integer ipsec_local_spi_c, |
| 58 | integer ipsec_local_spi_s, |
| 59 | integer ipsec_remote_spi_c optional, |
| 60 | integer ipsec_remote_spi_s optional, |
Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 61 | SipUrl registrar_sip_req_uri, |
| 62 | SipAddr registrar_sip_record, |
| 63 | CallidString registrar_sip_call_id, |
| 64 | integer registrar_sip_seq_nr, |
| 65 | Via local_via, |
| 66 | SipUrl local_sip_url_ext, |
| 67 | SipAddr local_sip_record, |
| 68 | Contact local_contact, |
| 69 | IMS_CallPars cp optional |
| 70 | } |
| 71 | type record of IMS_ConnHdlrPars IMS_ConnHdlrParsList; |
| 72 | |
| 73 | type record IMS_CallParsMT { |
| 74 | /* Whether to wait for COORD.receive(COORD_CMD_PICKUP) before accepting the call. */ |
| 75 | boolean wait_coord_cmd_pickup, |
| 76 | /* Whether to expect CANCEL instead of ACK as answer to our OK */ |
| 77 | boolean exp_cancel |
| 78 | } |
Pau Espin Pedrol | a2812ec | 2024-05-10 20:30:44 +0200 | [diff] [blame] | 79 | template (value) IMS_CallParsMT t_IMS_CallParsMT := { |
| 80 | wait_coord_cmd_pickup := false, |
| 81 | exp_cancel := false |
| 82 | } |
Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 83 | |
| 84 | type record IMS_CallPars { |
| 85 | SipAddr calling optional, |
| 86 | SipAddr called optional, |
| 87 | |
| 88 | SipAddr from_addr optional, |
| 89 | SipAddr to_addr optional, |
| 90 | |
| 91 | CallidString sip_call_id, |
| 92 | integer sip_seq_nr, |
| 93 | charstring sip_body optional, |
| 94 | |
| 95 | charstring local_rtp_addr, |
| 96 | uint16_t local_rtp_port, |
| 97 | |
| 98 | SDP_Message peer_sdp optional, |
| 99 | IMS_CallParsMT mt |
| 100 | } |
| 101 | |
Pau Espin Pedrol | a2812ec | 2024-05-10 20:30:44 +0200 | [diff] [blame] | 102 | template (value) IMS_CallPars t_IMS_CallPars(charstring local_rtp_addr, |
| 103 | uint16_t local_rtp_port := 0, |
| 104 | template (omit) SipAddr calling := omit, |
| 105 | template (omit) SipAddr called := omit) := { |
| 106 | calling := calling, |
| 107 | called := called, |
| 108 | from_addr := omit, |
| 109 | to_addr := omit, |
| 110 | sip_call_id := hex2str(f_rnd_hexstring(15)), |
| 111 | sip_seq_nr := f_sip_rand_seq_nr(), |
| 112 | sip_body := omit, |
| 113 | local_rtp_addr := local_rtp_addr, |
| 114 | local_rtp_port := local_rtp_port, |
| 115 | peer_sdp := omit, |
| 116 | mt := t_IMS_CallParsMT |
| 117 | } |
| 118 | |
| 119 | template (value) IMS_ConnHdlrPars t_IMS_Pars(charstring local_sip_host, |
| 120 | uint16_t local_sip_port, |
| 121 | charstring user, |
| 122 | charstring display_name := "Anonymous", |
| 123 | charstring password := "secret", |
| 124 | template (omit) IMS_CallPars cp := omit) := { |
| 125 | t_guard := 30.0, |
| 126 | realm := local_sip_host, |
| 127 | local_sip_host := local_sip_host, |
| 128 | local_sip_port := local_sip_port, |
| 129 | remote_sip_host := omit, |
| 130 | remote_sip_port := omit, |
| 131 | user := user, |
| 132 | display_name := f_sip_str_quote(display_name), |
| 133 | password := password, |
| 134 | ipsec_local_spi_c := 4142, |
| 135 | ipsec_local_spi_s := 4143, |
| 136 | ipsec_remote_spi_c := omit, |
| 137 | ipsec_remote_spi_s := omit, |
| 138 | registrar_sip_req_uri := valueof(ts_SipUrlHost(local_sip_host)), |
| 139 | registrar_sip_record := ts_SipAddr(ts_HostPort(local_sip_host), |
| 140 | ts_UserInfo(user), |
| 141 | f_sip_str_quote(display_name)), |
| 142 | registrar_sip_call_id := hex2str(f_rnd_hexstring(15)) & "@" & local_sip_host, |
| 143 | registrar_sip_seq_nr := f_sip_rand_seq_nr(), |
| 144 | local_via := ts_Via_from(ts_HostPort(local_sip_host, local_sip_port)), |
| 145 | local_sip_url_ext := ts_SipUrl(ts_HostPort(local_sip_host, local_sip_port), |
| 146 | ts_UserInfo(user)), |
| 147 | local_sip_record := ts_SipAddr(ts_HostPort(local_sip_host), |
| 148 | ts_UserInfo(user)), |
| 149 | local_contact := valueof(ts_Contact({ |
| 150 | ts_ContactAddress( |
| 151 | ts_Addr_Union_SipUrl(ts_SipUrl(ts_HostPort( |
| 152 | local_sip_host, |
| 153 | local_sip_port), |
| 154 | ts_UserInfo(user))), |
| 155 | omit) |
| 156 | })), |
| 157 | cp := cp |
| 158 | } |
| 159 | |
| 160 | private altstep as_Tguard() runs on IMS_ConnHdlr { |
| 161 | [] g_Tguard.timeout { |
| 162 | setverdict(fail, "Tguard timeout"); |
| 163 | mtc.stop; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | type function ims_void_fn(charstring id) runs on IMS_ConnHdlr; |
| 168 | function f_ims_handler_init(ims_void_fn fn, charstring id, IMS_ConnHdlrPars pars) |
| 169 | runs on IMS_ConnHdlr { |
| 170 | g_name := id; |
| 171 | g_pars := pars; |
| 172 | g_Tguard.start(pars.t_guard); |
| 173 | activate(as_Tguard()); |
| 174 | |
| 175 | /* call the user-supied test case function */ |
| 176 | fn.apply(id); |
| 177 | } |
| 178 | |
| 179 | private altstep as_SIP_fail_req(charstring exp_msg_str := "") runs on IMS_ConnHdlr |
| 180 | { |
| 181 | var PDU_SIP_Request sip_req; |
| 182 | [] SIP.receive(PDU_SIP_Request:?) -> value sip_req { |
| 183 | Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, |
| 184 | log2str(g_name & ": Received unexpected SIP Req message := ", sip_req, "\nvs exp := ", exp_msg_str)); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | private altstep as_SIP_fail_resp(charstring exp_msg_str := "") runs on IMS_ConnHdlr |
| 189 | { |
| 190 | var PDU_SIP_Response sip_resp; |
| 191 | [] SIP.receive(PDU_SIP_Response:?) -> value sip_resp { |
| 192 | Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, |
| 193 | log2str(g_name & ": Received unexpected SIP Resp message := ", sip_resp, "\nvs exp := ", exp_msg_str)); |
| 194 | } |
| 195 | } |
| 196 | |
| 197 | private function f_ims_validate_register_contact(Contact rx_contact) |
| 198 | { |
| 199 | /* IMS contact shows up like this: |
| 200 | * Contact: <sip:8adf9f3d-9342-4060-aa4f-a909f37fd6f6@192.168.101.2:5060>;+g.3gpp.accesstype="cellular2";video;audio;+g.3gpp.smsip;+g.3gpp.nw-init-ussi;+g.3gpp.icsi-ref="urn%3Aurn-7%3A3gpp-service.ims.icsi.mmtel";+sip.instance="<urn:gsma:imei:35589811-338445-0>" |
| 201 | */ |
| 202 | /* TODO: "that the UE must include the IMS Communication Service Identifier (ICSI) |
| 203 | in the contact: header to indicate IMS Multimedia Telephony." */ |
| 204 | /* TODO: "The UE must include an IMEI URN in the +sip.instance header field |
| 205 | parameter of the contact: header." */ |
| 206 | /* TODO: "If the UE supports SMS over IP, it must include the feature tag |
| 207 | “+g.3gpp.smsip” in the contact: header." */ |
| 208 | /* TODO: "If the UE supports conversational audio and video service, then this must |
| 209 | be indicated by adding a “video” media feature tag to the contact: header." */ |
| 210 | } |
| 211 | |
| 212 | private function f_ims_parse_security_client(Security_client security_client) runs on IMS_ConnHdlr |
| 213 | { |
| 214 | var boolean found := false; |
| 215 | for (var integer i := 0; i < lengthof(security_client.sec_mechanism_list); i := i + 1) { |
| 216 | var Security_mechanism sec_mec := security_client.sec_mechanism_list[i]; |
| 217 | if (sec_mec.mechanism_name != "ipsec-3gpp") { |
| 218 | log("Skipping Security Mechansim: ", sec_mec.mechanism_name); |
| 219 | continue; |
| 220 | } |
| 221 | var SemicolonParam_List sec_pars := sec_mec.mechanism_params; |
| 222 | var charstring par_val; |
| 223 | par_val := f_sip_param_get_value_present_or_fail(sec_pars, "alg"); |
| 224 | if (par_val != "hmac-sha-1-96") { |
| 225 | log("Skipping Security Mechansim Algo: ", par_val); |
| 226 | continue; |
| 227 | } |
| 228 | par_val := f_sip_param_get_value_present_or_fail(sec_pars, "spi-c"); |
| 229 | g_pars.ipsec_remote_spi_c := str2int(par_val); |
| 230 | par_val := f_sip_param_get_value_present_or_fail(sec_pars, "spi-s"); |
| 231 | g_pars.ipsec_remote_spi_s := str2int(par_val); |
| 232 | found := true; |
| 233 | break; |
| 234 | } |
| 235 | |
| 236 | if (not found) { |
| 237 | Misc_Helpers.f_shutdown(__BFILE__, __LINE__, fail, |
| 238 | log2str(g_name & "alg=hmac-sha-1-96 not found: ", security_client)); |
| 239 | } |
| 240 | |
| 241 | log("ipsec: remote_spi_c=", g_pars.ipsec_remote_spi_c, " remote_spi_s=", g_pars.ipsec_remote_spi_s, |
| 242 | "local_spi_c=", g_pars.ipsec_local_spi_c, " local_spi_s=", g_pars.ipsec_local_spi_s); |
| 243 | } |
| 244 | |
| 245 | private function f_ims_setup_ipsec(PDU_SIP_Request req_req) runs on IMS_ConnHdlr |
| 246 | { |
| 247 | var Security_client security_client := req_req.msgHeader.security_client; |
| 248 | f_ims_parse_security_client(security_client); |
| 249 | } |
| 250 | |
| 251 | /* Peer is calling us, accept it: */ |
| 252 | altstep as_IMS_register(boolean exp_update_to_direct_rtp := true, |
| 253 | boolean fail_others := true) runs on IMS_ConnHdlr |
| 254 | { |
| 255 | var template (present) PDU_SIP_Request exp_req := |
| 256 | tr_SIP_REGISTER(g_pars.registrar_sip_req_uri, |
| 257 | ?, |
| 258 | tr_SipAddr(), |
| 259 | tr_SipAddr(), |
| 260 | tr_Via_from(?), |
| 261 | require := tr_Require(superset("sec-agree")), |
| 262 | security_client := tr_Security_client(superset(tr_Security_mechanism("ipsec-3gpp", |
| 263 | superset(tr_Param("alg","hmac-sha-1-96"))))), |
| 264 | supported := tr_Supported(superset("path", "sec-agree"))); |
| 265 | var charstring sip_expect_str := log2str(exp_req); |
| 266 | |
| 267 | [] SIP.receive(exp_req) -> value g_rx_sip_req { |
| 268 | var template (value) PDU_SIP_Response tx_resp; |
| 269 | var Via via; |
| 270 | var CallidString sip_call_id; |
| 271 | var Contact contact; |
| 272 | var template (value) SipAddr from_addr; |
| 273 | var template (value) SipAddr to_addr; |
| 274 | var template (value) CommaParam_List digestCln ; |
| 275 | var template (value) WwwAuthenticate wwwAuthenticate; |
| 276 | var template (value) Security_server security_server; |
| 277 | var template (value) Server server_name := ts_Server({c_sip_server_name}); |
| 278 | var template (value) Supported supported := ts_Supported({"sec-agree"}); |
| 279 | var Authorization authorization; |
| 280 | var integer sip_seq_nr; |
| 281 | var charstring tx_sdp; |
| 282 | |
| 283 | sip_call_id := g_rx_sip_req.msgHeader.callId.callid; |
| 284 | via := g_rx_sip_req.msgHeader.via; |
| 285 | via.viaBody[0].viaParams := f_sip_param_set(via.viaBody[0].viaParams, "rport", "1234"); /* TODO: set remote src port of the REGISTER */ |
| 286 | from_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.fromField.addressField, |
| 287 | g_rx_sip_req.msgHeader.fromField.fromParams); |
| 288 | to_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.toField.addressField, |
| 289 | g_rx_sip_req.msgHeader.toField.toParams); |
| 290 | sip_seq_nr := g_rx_sip_req.msgHeader.cSeq.seqNumber; |
| 291 | |
| 292 | contact := g_rx_sip_req.msgHeader.contact; |
| 293 | f_ims_validate_register_contact(contact); |
| 294 | |
| 295 | /* TODO: Validate "Expires" is 600000 */ |
| 296 | /* TODO: validate presence of: |
| 297 | * Security-Client: ipsec-3gpp; alg=hmac-md5-96; ealg=des-ede3-cbc; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718,ipsec-3gpp; alg=hmac-md5-96; ealg=aes-cbc; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718,ipsec-3gpp; alg=hmac-md5-96; ealg=null; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718,ipsec-3gpp; alg=hmac-sha-1-96; ealg=des-ede3-cbc; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718,ipsec-3gpp; alg=hmac-sha-1-96; ealg=aes-cbc; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718,ipsec-3gpp; alg=hmac-sha-1-96; ealg=null; spi-c=431842084; spi-s=650017092; port-c=41271; port-s=41718 |
| 298 | */ |
| 299 | |
| 300 | /* Tx 100 Tyring */ |
| 301 | tx_resp := ts_SIP_Response_Trying(sip_call_id, |
| 302 | from_addr, |
| 303 | to_addr, |
| 304 | via, |
| 305 | sip_seq_nr, |
| 306 | "REGISTER", |
| 307 | allow := omit, |
| 308 | server := server_name, |
| 309 | userAgent := omit); |
| 310 | SIP.send(tx_resp); |
| 311 | |
| 312 | f_ims_setup_ipsec(g_rx_sip_req); |
| 313 | |
| 314 | to_addr.params := f_sip_param_set(to_addr.params, "tag", f_sip_rand_tag()); |
| 315 | |
| 316 | digestCln := { |
| 317 | ts_Param("realm", f_sip_str_quote(g_pars.realm)), |
| 318 | ts_Param("qop", f_sip_str_quote("auth")), |
| 319 | ts_Param("algorithm", "AKAv1-MD5"), |
| 320 | ts_Param("nonce", f_sip_str_quote("FJh2MfZfjjeIoHmLbrzQjvbhmnzLAoAAoGsZyVRFFuU=")) |
| 321 | /* "opaque not needed in IMS "*/ |
| 322 | }; |
| 323 | wwwAuthenticate := ts_WwwAuthenticate( { ts_Challenge_digestCln(digestCln) } ) |
| 324 | |
| 325 | /* Security-Server: ipsec-3gpp;q=0.1;prot=esp;mod=trans;spi-c=4096;spi-s=4097;port-c=5104;port-s=6104;alg=hmac-sha-1-96;ealg=null */ |
| 326 | var template (value) SemicolonParam_List sec_params := { |
| 327 | ts_Param("q", "0.1"), |
| 328 | ts_Param("prot", "esp"), |
| 329 | ts_Param("mod", "trans"), |
| 330 | ts_Param("spi-c", int2str(g_pars.ipsec_local_spi_c)), |
| 331 | ts_Param("spi-s", int2str(g_pars.ipsec_local_spi_s)), |
| 332 | ts_Param("port-c", int2str(g_pars.local_sip_port)), |
| 333 | ts_Param("port-s", int2str(g_pars.local_sip_port)), |
| 334 | ts_Param("alg", "hmac-sha-1-96"), |
| 335 | ts_Param("ealg", "null") |
| 336 | }; |
| 337 | security_server := ts_Security_server({ |
| 338 | ts_Security_mechanism("ipsec-3gpp", sec_params) |
| 339 | }); |
| 340 | /* Tx 401 Unauthorized |
| 341 | * TODO: with IMS params */ |
| 342 | tx_resp := ts_SIP_Response_Unauthorized(sip_call_id, |
| 343 | from_addr, |
| 344 | to_addr, |
| 345 | via, |
| 346 | wwwAuthenticate, |
| 347 | sip_seq_nr, |
| 348 | "REGISTER", |
| 349 | security_server := security_server, |
| 350 | server := server_name, |
| 351 | supported := supported, |
| 352 | userAgent := omit); |
| 353 | SIP.send(tx_resp); |
| 354 | |
| 355 | /* TODO: Generate expected Authoritzation based on AKAv1-MD5: */ |
| 356 | /*authorization := f_sip_digest_gen_Authorization(valueof(wwwAuthenticate), |
| 357 | g_pars.user, g_pars.password, |
| 358 | "REGISTER", |
| 359 | f_sip_SipUrl_to_str(g_pars.registrar_sip_record.addr.nameAddr.addrSpec)) |
| 360 | */ |
| 361 | /* TODO: match Authorization from above: */ |
| 362 | exp_req := |
| 363 | tr_SIP_REGISTER(g_pars.registrar_sip_req_uri, |
| 364 | ?, |
| 365 | tr_SipAddr(), |
| 366 | tr_SipAddr(), |
| 367 | tr_Via_from(?)); |
| 368 | SIP.receive(exp_req) -> value g_rx_sip_req; |
| 369 | |
| 370 | sip_call_id := g_rx_sip_req.msgHeader.callId.callid; |
| 371 | via := g_rx_sip_req.msgHeader.via; |
| 372 | from_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.fromField.addressField, |
| 373 | g_rx_sip_req.msgHeader.fromField.fromParams); |
| 374 | to_addr := ts_SipAddr_from_Addr_Union(g_rx_sip_req.msgHeader.toField.addressField, |
| 375 | g_rx_sip_req.msgHeader.toField.toParams); |
| 376 | to_addr.params := f_sip_param_set(to_addr.params, "tag", f_sip_rand_tag()); |
| 377 | sip_seq_nr := g_rx_sip_req.msgHeader.cSeq.seqNumber; |
| 378 | |
| 379 | /* TODO: Add following fields: |
| 380 | * Supported: sec-agree |
| 381 | * Security-Server: ipsec-3gpp;q=0.1;prot=esp;mod=trans;spi-c=4096;spi-s=4097;port-c=5104;port-s=6104;alg=hmac-sha-1-96;ealg=null |
| 382 | * */ |
| 383 | |
| 384 | tx_resp := ts_SIP_Response(sip_call_id, |
| 385 | from_addr, |
| 386 | to_addr, |
| 387 | "REGISTER", 200, |
| 388 | sip_seq_nr, |
| 389 | "OK", |
| 390 | via); |
| 391 | SIP.send(tx_resp); |
| 392 | } |
| 393 | [fail_others] as_SIP_fail_resp(sip_expect_str); |
| 394 | [fail_others] as_SIP_fail_req(sip_expect_str); |
| 395 | |
| 396 | } |
| 397 | |
Pau Espin Pedrol | ac8a054 | 2024-04-19 17:30:57 +0200 | [diff] [blame] | 398 | } |