Add enc/dec function for NAS Service Reject library

2025-04-10 15:35:55 +02:00
parent 25bc1bd89a
commit 5af4b89203
3 changed files with 200 additions and 0 deletions
@@ -2,6 +2,7 @@ add_library(fgs_5gmm_lib OBJECT
    fgmm_lib.c
    fgs_service_request.c
    fgmm_service_accept.c
+    fgmm_service_reject.c
    RegistrationRequest.c
    RegistrationAccept.c
    FGSIdentityResponse.c
@@ -0,0 +1,154 @@
+/*
+ * 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_service_reject.h"
+#include <string.h>
+#include <arpa/inet.h> // For htons and ntohs
+#include <stdlib.h> // For malloc and free
+#include "common/utils/ds/byte_array.h"
+#include "common/utils/utils.h"
+#include "fgmm_lib.h"
+
+#define SERVICE_REJECT_MIN_LEN 1 // 1 octet
+
+/** @brief Encode Service Reject (8.2.18 of 3GPP TS 24.501) */
+int encode_fgs_service_reject(byte_array_t *buffer, const fgs_service_reject_msg_t *msg)
+{
+  if (buffer->len < SERVICE_REJECT_MIN_LEN) {
+    PRINT_NAS_ERROR("Failed to encode Service Reject: missing Cause IE!\n");
+    return -1;
+  }
+
+  byte_array_t ba = *buffer; // Local copy of buffer
+  int encoded = 0;
+
+  // 5GMM cause (Mandatory)
+  buffer->buf[encoded++] = msg->cause;
+  UPDATE_BYTE_ARRAY(ba, 1);
+
+  // PDU Session Status (Optional)
+  if (msg->has_psi_status) {
+    ENCODE_NAS_IE(ba, encode_pdu_session_ie(&ba, IEI_PDU_SESSION_STATUS, msg->psi_status), encoded);
+  }
+
+  // T3446 Timer (Optional)
+  if (msg->t3446) {
+    ENCODE_NAS_IE(ba, encode_gprs_timer_ie(&ba, IEI_T3446_VALUE, msg->t3446), encoded);
+  }
+
+  // T3448 Timer (Optional)
+  if (msg->t3448) {
+    ENCODE_NAS_IE(ba, encode_gprs_timer_ie(&ba, IEI_T3448_VALUE, msg->t3448), encoded);
+  }
+
+  return encoded;
+}
+
+/** @brief Decode Service Reject (8.2.18 of 3GPP TS 24.501) */
+int decode_fgs_service_reject(fgs_service_reject_msg_t *msg, const byte_array_t *buffer)
+{
+  if (buffer->len < SERVICE_REJECT_MIN_LEN) {
+    PRINT_NAS_ERROR("Nothing to decode: missing Cause IE!\n");
+    return -1;
+  }
+
+  byte_array_t ba = *buffer; // Local copy of buffer to be used in the decoding sub-functions
+  uint32_t decoded = 0;
+
+  // Cause (Mandatory)
+  msg->cause = buffer->buf[decoded++];
+  UPDATE_BYTE_ARRAY(ba, 1);
+
+  // Decode Optional IEs
+  while (decoded < buffer->len) {
+    uint8_t iei = buffer->buf[decoded++];
+    UPDATE_BYTE_ARRAY(ba, 1); // Skip IEI
+
+    switch (iei) {
+      case IEI_PDU_SESSION_STATUS:
+        msg->has_psi_status = true;
+        DECODE_NAS_IE(ba, decode_pdu_session_ie(msg->psi_status, &ba), decoded);
+        break;
+
+      case IEI_T3448_VALUE:
+        msg->t3448 = malloc_or_fail(sizeof(*msg->t3448));
+        DECODE_NAS_IE(ba, decode_gprs_timer_ie(msg->t3448, (const byte_array_t *)&ba), decoded);
+        break;
+
+      case IEI_T3446_VALUE:
+        msg->t3446 = malloc_or_fail(sizeof(*msg->t3446));
+        DECODE_NAS_IE(ba, decode_gprs_timer_ie(msg->t3446, (const byte_array_t *)&ba), decoded);
+        break;
+
+      case IEI_EAPMSG:
+        DECODE_NAS_IE(ba, decode_eap_msg_ie((const byte_array_t *)&ba), decoded);
+        break;
+
+      case IEI_CAG_INFO_LIST: {
+        int cag_list_len = (buffer->buf[decoded] << 8) | buffer->buf[decoded + 1];
+        int cag_len = cag_list_len + 2; // encoded content + 2 octets for the length IE
+        decoded += cag_len;
+        UPDATE_BYTE_ARRAY(ba, cag_len);
+        PRINT_NAS_ERROR("CAG information list IE in NAS Service Reject is not handled\n");
+      } break;
+
+      default:
+        PRINT_NAS_ERROR("Uknown or invalid NAS Service Reject IEI %d\n", iei);
+        return -1;
+    }
+  }
+
+  return decoded;
+}
+
+/** @brief Equality check for Service Reject (enc/dec) */
+bool eq_service_reject(const fgs_service_reject_msg_t *a, const fgs_service_reject_msg_t *b)
+{
+  _NAS_EQ_CHECK_INT(a->cause, b->cause);
+  _NAS_EQ_CHECK_INT(a->has_psi_status, b->has_psi_status);
+  if (a->has_psi_status && b->has_psi_status) {
+    for (int i = 0; i < MAX_NUM_PSI; i++)
+      _NAS_EQ_CHECK_INT(a->psi_status[i], b->psi_status[i]);
+  }
+  if (a->t3448 != NULL || b->t3448 != NULL) {
+    if (a->t3448 == NULL || b->t3448 == NULL) {
+      PRINT_NAS_ERROR("t3448 equality check failed\n");
+      return false;
+    }
+    if (!eq_gprs_timer(a->t3448, b->t3448))
+      return false;
+  }
+  if (a->t3446 != NULL || b->t3446 != NULL) {
+    if (a->t3446 == NULL || b->t3446 == NULL) {
+      PRINT_NAS_ERROR("t3448 equality check failed\n");
+      return false;
+    }
+    if (!eq_gprs_timer(a->t3446, b->t3446))
+      return false;
+  }
+  return true;
+}
+
+void free_fgs_service_reject(fgs_service_reject_msg_t *msg)
+{
+  free(msg->t3446);
+  free(msg->t3448);
+}
@@ -0,0 +1,45 @@
+/*
+ * 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 FGS_service_reject_H
+#define FGS_service_reject_H
+
+#include <stdint.h>
+#include "fgmm_lib.h"
+
+typedef struct {
+  // 5GMM cause (Mandatory)
+  cause_id_t cause;
+  // T3346 Value (Optional)
+  gprs_timer_t *t3446;
+  // PDU Session Status (Optional)
+  uint8_t psi_status[MAX_NUM_PSI];
+  bool has_psi_status;
+  // T3448 Value (Optional)
+  gprs_timer_t *t3448;
+} fgs_service_reject_msg_t;
+
+int decode_fgs_service_reject(fgs_service_reject_msg_t *msg, const byte_array_t *buffer);
+int encode_fgs_service_reject(byte_array_t *buffer, const fgs_service_reject_msg_t *msg);
+void free_fgs_service_reject(fgs_service_reject_msg_t *msg);
+bool eq_service_reject(const fgs_service_reject_msg_t *a, const fgs_service_reject_msg_t *b);
+
+#endif /* FGS_service_reject_H */