Add enc/dec lib for NAS Authentication Reject and unit test

openair3/NAS/NR_UE/5GS/5GMM/MSG/CMakeLists.txt

@@ -14,6 +14,7 @@ add_library(fgs_5gmm_lib OBJECT
     FGSUplinkNasTransport.c
     FGSDeregistrationRequestUEOriginating.c
     fgmm_authentication_failure.c
+    fgmm_authentication_reject.c
 )
 
 target_link_libraries(fgs_5gmm_lib PUBLIC fgs_5gmm_ies_lib)

openair3/NAS/NR_UE/5GS/5GMM/MSG/fgmm_authentication_reject.c

@@ -0,0 +1,69 @@
+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#include "fgmm_authentication_reject.h"
+#include <string.h>
+#include <arpa/inet.h> // For htons and ntohs
+#include <stdlib.h> // For malloc and free
+#include "fgmm_lib.h"
+
+#define MIN_AUTH_REJECT_LEN 3
+
+/** @brief Encode Authentication Reject (8.2.5 of 3GPP TS 24.501) */
+int encode_fgmm_auth_reject(byte_array_t *buffer, const fgmm_auth_reject_msg_t *msg)
+{
+  uint32_t encoded = 0;
+
+  const byte_array_t *eap_msg = &msg->eap_msg;
+  if (eap_msg->len > 0) {
+    return encode_eap_msg_ie(buffer, eap_msg);
+  }
+  return encoded;
+}
+
+/** @brief Decode Authentication Reject (8.2.5 of 3GPP TS 24.501)
+ *         the message contains only optional IEIs (EAP MSG) */
+int decode_fgmm_auth_reject(fgmm_auth_reject_msg_t *msg, const byte_array_t *buffer)
+{
+  if (buffer->len < MIN_AUTH_REJECT_LEN) {
+    // No optional IEIs present
+    return 0;
+  }
+  byte_array_t ba = *buffer; // Local copy of buffer
+  uint32_t decoded = 0;
+  // Decode the IEI
+  uint8_t iei = buffer->buf[decoded++];
+  UPDATE_BYTE_ARRAY(ba, decoded);
+  if (iei == IEI_EAPMSG) {
+    return (decoded + decode_eap_msg_ie(&msg->eap_msg, &ba));
+  }
+  PRINT_NAS_ERROR("Expected EAP MSG but it is not present");
+  return -1;
+}
+
+bool eq_auth_reject(fgmm_auth_reject_msg_t *a, fgmm_auth_reject_msg_t *b)
+{
+  _NAS_EQ_CHECK_LONG(a->eap_msg.len, b->eap_msg.len);
+  if (a->eap_msg.len > 0) {
+    return !memcmp(a->eap_msg.buf, b->eap_msg.buf, a->eap_msg.len);
+  }
+  return true;
+}

openair3/NAS/NR_UE/5GS/5GMM/MSG/fgmm_authentication_reject.h

@@ -0,0 +1,38 @@
+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1 (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#ifndef FGMM_AUTH_REJECT_H
+#define FGMM_AUTH_REJECT_H
+
+#include <stdint.h>
+#include "fgmm_lib.h"
+#include "common/utils/ds/byte_array.h"
+
+typedef struct {
+  // EAP Message (Optional)
+  byte_array_t eap_msg;
+} fgmm_auth_reject_msg_t;
+
+int decode_fgmm_auth_reject(fgmm_auth_reject_msg_t *msg, const byte_array_t *buffer);
+int encode_fgmm_auth_reject(byte_array_t *buffer, const fgmm_auth_reject_msg_t *msg);
+bool eq_auth_reject(fgmm_auth_reject_msg_t *a, fgmm_auth_reject_msg_t *b);
+
+#endif /* FGMM_AUTH_REJECT_H */

openair3/NAS/NR_UE/5GS/tests/nas_lib_test.c

@@ -9,6 +9,7 @@
 #include "fgmm_service_reject.h"
 #include "fgmm_authentication_failure.h"
 #include "FGSNASSecurityModeReject.h"
+#include "fgmm_authentication_reject.h"
 #include "nr_nas_msg.h"
 
 void exit_function(const char *file, const char *function, const int line, const char *s, const int assert)
@@ -298,6 +299,44 @@ static void test_security_mode_reject(void)
   AssertFatal(eq_sec_mode_reject(&orig, &dec), "test_sec_mode_reject() failed: original and decoded messages do not match\n");
 }
 
+/**
+ * @brief Test NAS Authentication Reject enc/dec
+ */
+static void test_auth_reject(void)
+{
+  // Dummy NAS Authentication Reject message
+  uint8_t dummy_eap_msg[] = {0x12, 0x34, 0x56, 0x78, 0x91, 0x01, 0x23}; // Example EAP message
+  fgmm_auth_reject_msg_t orig = {
+      .eap_msg.len = sizeof(dummy_eap_msg),
+  };
+  orig.eap_msg.buf = dummy_eap_msg;
+
+  // Expected encoded data
+  uint8_t expected_enc[] = {0x78, 0x00, 0x07, 0x12, 0x34, 0x56, 0x78, 0x91, 0x01, 0x23};
+
+  // Buffer
+  uint8_t buf[10] = {0};
+  byte_array_t buffer = {.buf = buf, .len = sizeof(buf)};
+
+  // Encode
+  int encoded_length = encode_fgmm_auth_reject(&buffer, &orig);
+  AssertFatal(encoded_length >= 0, "encode_fgmm_auth_reject() failed\n");
+
+  // Compare the raw encoded buffer with expected encoded data
+  AssertFatal(encoded_length == sizeof(expected_enc), "Encoded length mismatch %d != %ld \n", encoded_length, sizeof(expected_enc));
+  AssertFatal(memcmp(buffer.buf, expected_enc, encoded_length) == 0, "Encoding mismatch!\n");
+
+  // Decode
+  fgmm_auth_reject_msg_t dec = {0};
+  uint8_t eap_msg[1500] = {0};
+  dec.eap_msg.buf = eap_msg;
+  int decoded_length = decode_fgmm_auth_reject(&dec, &buffer);
+  AssertFatal(decoded_length >= 0, "decode_fgmm_auth_reject() failed\n");
+
+  // Compare original and decoded messages
+  AssertFatal(eq_auth_reject(&orig, &dec), "test_auth_reject() failed: original and decoded messages do not match\n");
+}
+
 int main()
 {
   test_regression_registration_accept();
@@ -305,6 +344,7 @@ int main()
   test_service_accept();
   test_service_reject();
   test_auth_failure();
+  test_auth_reject();
   test_security_mode_reject();
   return 0;
 }