[AMF] Fix UE context transfer when only NRF is client (#3880)

* [AMF] Fix UE context transfer when only NRF is client

If UE context transfer is initiated and the new AMF does not get the
old AMF from NRF or no UE context is retrieved from the old AMF,
we do not want to reject UE registration. Send identity request instead.
Test "transfer-error-case" is added into the commit.

* [tests] Unite tests for UE context transfer

All tests for UE context transfer with different configs are placed
into test folder transfer.

* [tests] Make two binaries for UE context transfer tests

For each test config a different test binary is created.

configs/meson.build

@@ -41,6 +41,7 @@ example_conf = '''
     srsenb.yaml
     non3gpp.yaml
     transfer.yaml
+    transfer-error-case.yaml
 '''.split()
 
 foreach file : example_conf

configs/transfer-error-case.yaml.in

@@ -0,0 +1,266 @@
+db_uri: mongodb://localhost/open5gs
+
+logger:
+
+test:
+  serving:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+
+global:
+  parameter:
+#    no_nrf: true
+    no_scp: true
+    no_sepp: true
+#    no_amf: true
+#    no_smf: true
+#    no_upf: true
+#    no_ausf: true
+#    no_udm: true
+#    no_pcf: true
+#    no_nssf: true
+#    no_bsf: true
+#    no_udr: true
+    no_mme: true
+    no_sgwc: true
+    no_sgwu: true
+    no_pcrf: true
+    no_hss: true
+
+smf:
+  sbi:
+    server:
+      - address: 127.0.0.4
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+  pfcp:
+    server:
+      - address: 127.0.0.4
+    client:
+      upf:
+        - address: 127.0.0.7
+  gtpc:
+    server:
+      - address: 127.0.0.4
+  gtpu:
+    server:
+      - address: 127.0.0.4
+  metrics:
+    server:
+      - address: 127.0.0.4
+        port: 9090
+  session:
+    - subnet: 10.45.0.0/16
+      gateway: 10.45.0.1
+    - subnet: 2001:db8:cafe::/48
+      gateway: 2001:db8:cafe::1
+  dns:
+    - 8.8.8.8
+    - 8.8.4.4
+    - 2001:4860:4860::8888
+    - 2001:4860:4860::8844
+  mtu: 1400
+  freeDiameter:
+    identity: smf.localdomain
+    realm: localdomain
+    listen_on: 127.0.0.4
+    no_fwd: true
+    load_extension:
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dbg_msg_dumps.fdx
+        conf: 0x8888
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_rfc5777.fdx
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_mip6i.fdx
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_nasreq.fdx
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_nas_mipv6.fdx
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_dcca.fdx
+      - module: @build_subprojects_freeDiameter_extensions_dir@/dict_dcca_3gpp/dict_dcca_3gpp.fdx
+    connect:
+      - identity: pcrf.localdomain
+        address: 127.0.0.9
+
+amf:
+  sbi:
+    server:
+      - address: 127.0.0.5
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+  ngap:
+    server:
+      - address: 127.0.0.5
+  metrics:
+    server:
+      - address: 127.0.0.5
+        port: 9090
+  guami:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      amf_id:
+        region: 2
+        set: 1
+        pointer: 31
+  tai:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      tac: 1
+  plmn_support:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      s_nssai:
+        - sst: 1
+  security:
+    integrity_order : [ NIA2, NIA1, NIA0 ]
+    ciphering_order : [ NEA0, NEA1, NEA2 ]
+  network_name:
+    full: Open5GS
+  amf_name: open5gs-amf0
+  time:
+    t3512:
+      value: 540     # 9 mintues * 60 = 540 seconds
+
+# amf #2
+amf:
+  sbi:
+    server:
+      - address: 127.0.0.50
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+  ngap:
+    server:
+      - address: 127.0.0.50
+  metrics:
+    server:
+      - address: 127.0.0.50
+        port: 9090
+  guami:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      amf_id:
+        region: 2
+        set: 1
+        pointer: 30
+  tai:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      tac: 1
+  plmn_support:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+      s_nssai:
+        - sst: 1
+  security:
+    integrity_order : [ NIA2, NIA1, NIA0 ]
+    ciphering_order : [ NEA0, NEA1, NEA2 ]
+  network_name:
+    full: Open5GS
+  amf_name: open5gs-amf1
+  time:
+    t3512:
+      value: 540     # 9 mintues * 60 = 540 seconds
+
+upf:
+  pfcp:
+    server:
+      - address: 127.0.0.7
+  gtpu:
+    server:
+      - address: 127.0.0.7
+  session:
+    - subnet: 10.45.0.0/16
+      gateway: 10.45.0.1
+    - subnet: 2001:db8:cafe::/48
+      gateway: 2001:db8:cafe::1
+  metrics:
+    server:
+      - address: 127.0.0.7
+        port: 9090
+
+nrf:
+  sbi:
+    server:
+      - address: 127.0.0.10
+        port: 7777
+  serving:
+    - plmn_id:
+        mcc: 999
+        mnc: 70
+
+ausf:
+  sbi:
+    server:
+      - address: 127.0.0.11
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+
+udm:
+  hnet:
+    - id: 1
+      scheme: 1
+      key: @build_configs_dir@/open5gs/hnet/curve25519-1.key
+    - id: 2
+      scheme: 2
+      key: @build_configs_dir@/open5gs/hnet/secp256r1-2.key
+  sbi:
+    server:
+      - address: 127.0.0.12
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+
+pcf:
+  sbi:
+    server:
+      - address: 127.0.0.13
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+  metrics:
+    server:
+      - address: 127.0.0.13
+        port: 9090
+
+nssf:
+  sbi:
+    server:
+      - address: 127.0.0.14
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+      nsi:
+        - uri: http://127.0.0.10:7777
+          s_nssai:
+            sst: 1
+bsf:
+  sbi:
+    server:
+      - address: 127.0.0.15
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777
+
+udr:
+  sbi:
+    server:
+      - address: 127.0.0.20
+        port: 7777
+    client:
+      nrf:
+        - uri: http://127.0.0.10:7777