+/*******************************************************************
+ *
+ * @brief Process received Handover Request
+ *
+ * @details
+ *
+ * Function : XNAPProcHandoverReq
+ *
+ * Functionality:
+ * 1. Unpack Cell Id from msg and find DU to which it belongs
+ * 2. Create UE context for UE in handover and store in DU DB
+ * 3. Decode the F1AP UE context modification msg received in
+ * XNAP message buffer and extract UE configurations
+ * 4. Send UE context setup request to DU with these configs
+ *
+ * @params[in] Pointer to destination Id
+ * Pointer to message buffer
+ * @return void
+ *
+ ******************************************************************/
+void XNAPProcHandoverReq(uint32_t destId, Buffer *mBuf)
+{
+ uint8_t duIdx, cellIdx;
+ uint8_t cuUeF1apIdSrc;
+ uint32_t cellId;
+ DuDb *duDb;
+ CuCellCb *cellCb;
+
+ DU_LOG("\nINFO --> CU STUB : Received Handover Request");
+
+ /* Find DU Db and Cell Cb from cellId */
+ CMCHKUNPK(oduPackUInt32, &(cellId), mBuf);
+ for(duIdx = 0; duIdx < cuCb.numDu; duIdx++)
+ {
+ duDb = &cuCb.duInfo[duIdx];
+ SEARCH_CELL_DB(cellIdx, duDb, cellId, cellCb)
+ if(cellCb)
+ break;
+ }
+ if(!cellCb)
+ {
+ DU_LOG("\nERROR --> CU_STUB: Failed to find Cell Id [%d] received in HO Request", cellId);
+ return;
+ }
+
+ /* Fetch CU UE F1AP ID of UE in handover assigned by source CU */
+ CMCHKUNPK(oduPackUInt8, &(cuUeF1apIdSrc), mBuf);
+
+ /* Filling temporary UE context which will be used to create actual UE context at
+ * CU later */
+ CU_ALLOC(duDb->tempUeCtxtInHo, sizeof(CuUeCb));
+ if(!duDb->tempUeCtxtInHo)
+ {
+ DU_LOG("\nERROR --> XNAP : Failed to allocate memory to temporary UE context for UE in handover");
+ return;
+ }
+ memset(duDb->tempUeCtxtInHo, 0, sizeof(CuUeCb));
+ duDb->tempUeCtxtInHo->cellCb = cellCb;
+ duDb->tempUeCtxtInHo->gnbCuUeF1apId = ++cuCb.gnbCuUeF1apIdGenerator;
+ duDb->tempUeCtxtInHo->state = UE_HANDOVER_IN_PROGRESS;
+ duDb->tempUeCtxtInHo->hoInfo.HOType = Xn_Based_Inter_CU_HO;
+ duDb->tempUeCtxtInHo->hoInfo.srcNodeId = destId;
+ duDb->tempUeCtxtInHo->hoInfo.tgtNodeId = cuCb.cuCfgParams.cuId;
+ duDb->tempUeCtxtInHo->hoInfo.tgtCellId = cellId;
+ duDb->tempUeCtxtInHo->hoInfo.cuUeF1apIdSrc = cuUeF1apIdSrc;
+ duDb->tempUeCtxtInHo->hoInfo.cuUeF1apIdTgt = duDb->tempUeCtxtInHo->gnbCuUeF1apId;
+
+ /* Decode UE context modification response msg received in Xn Msg */
+ char *recvBuf;
+ MsgLen recvBufLen, copyLen;
+ F1AP_PDU_t *f1apMsg = NULLP;
+ F1AP_PDU_t f1apasnmsg ;
+
+ f1apMsg = &f1apasnmsg;
+ memset(f1apMsg, 0, sizeof(F1AP_PDU_t));
+ if(F1APDecodeMsg(f1apMsg, mBuf, &recvBuf, &recvBufLen) != ROK)
+ {
+ DU_LOG("\nERROR --> F1AP : F1AP PDU decode failed");
+ return;
+ }
+ CU_FREE(recvBuf, recvBufLen);
+ procUeContextModificationResponse(duDb->duId, f1apMsg, NULL, 0);
+}
+
+/*******************************************************************
+ *
+ * @brief Build And send dummy Handover request ack to Peer CU
+ *
+ * @details
+ *
+ * Function : BuildAndSendHOReqAck
+ *
+ * Functionality:
+ * Build And send dummy Handover request ack to Peer CU
+ *
+ * @params[in] Pointer to UE Cb
+ * Message to be sent
+ * Message Length
+ * @return void
+ *
+ ******************************************************************/
+void BuildAndSendHOReqAck(CuUeCb *ueCb, char *xnMsg, MsgLen xnMsgLen)
+{
+ Buffer *mBuf = NULLP;
+
+ if(ODU_GET_MSG_BUF(1, 1, &mBuf) == ROK)
+ {
+ if(ODU_ADD_POST_MSG_MULT((Data *)xnMsg, xnMsgLen, mBuf) == ROK)
+ {
+ CMCHKPK(oduUnpackUInt8, ueCb->gnbCuUeF1apId, mBuf);
+ CMCHKPK(oduUnpackUInt8, ueCb->hoInfo.cuUeF1apIdSrc, mBuf);
+ CMCHKPK(oduUnpackUInt8, HO_REQ_ACK, mBuf);
+ if(sctpSend(XN_INTERFACE, ueCb->hoInfo.srcNodeId, mBuf) != ROK)
+ {
+ DU_LOG("\nERROR --> CU_STUB: Failed to send handover request ack to peer CU");
+ }
+ }
+ }
+}
+
+/*******************************************************************
+ *
+ * @brief Process received Handover Request Ack
+ *
+ * @details
+ *
+ * Function : XNAPProcHandoverReqAck
+ *
+ * Functionality:
+ * 1. Unpack CU UE F1AP ID (by SCU) and search for UE CB and
+ * the corresponding DU DB (SDU)
+ * 2. Unpack CU UE F1AP ID (by TCU) and fill in UEcb->hoInfo
+ * 3. Decode the F1AP UE context setup response msg received in
+ * XNAP message buffer and extract UE configurations
+ * 4. Create RRC reconfig msg with these configurations
+ * 5. Send RRC Reconfig msg and Transmission Action = DO NOT TRANSMIT
+ * in UE context modification request to S DU
+ *
+ * @params[in] Pointer to destination Id
+ * Pointer to message buffer
+ * @return void
+ *
+ ******************************************************************/
+void XNAPProcHandoverReqAck(uint32_t destId, Buffer *mBuf)
+{
+ DU_LOG("\nINFO --> CU STUB : Received Handover Request Acknowledgement");
+}
+