rpcMain.c

/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include "lz4.h"
#include "os.h"
#include "rpcCache.h"
#include "rpcHead.h"
#include "rpcLog.h"
#include "rpcTcp.h"
#include "rpcUdp.h"
#include "taoserror.h"
#include "tglobal.h"
#include "thash.h"
#include "tidpool.h"
#include "tmd5.h"
#include "tmempool.h"
#include "tmsg.h"
#include "transportInt.h"
#include "tref.h"
#include "trpc.h"
#include "ttimer.h"
#include "tutil.h"

static pthread_once_t tsRpcInitOnce = PTHREAD_ONCE_INIT;

int tsRpcMaxUdpSize = 15000;  // bytes
int tsProgressTimer = 100;
// not configurable
int tsRpcMaxRetry;
int tsRpcHeadSize;
int tsRpcOverhead;

#ifndef USE_UV

typedef struct {
  int      sessions;      // number of sessions allowed
  int      numOfThreads;  // number of threads to process incoming messages
  int      idleTime;      // milliseconds;
  uint16_t localPort;
  int8_t   connType;
  int      index;  // for UDP server only, round robin for multiple threads
  char     label[TSDB_LABEL_LEN];

  char user[TSDB_UNI_LEN];         // meter ID
  char spi;                        // security parameter index
  char encrypt;                    // encrypt algorithm
  char secret[TSDB_PASSWORD_LEN];  // secret for the link
  char ckey[TSDB_PASSWORD_LEN];    // ciphering key

  void (*cfp)(void *parent, SRpcMsg *, SEpSet *);
  int (*afp)(void *parent, char *user, char *spi, char *encrypt, char *secret, char *ckey);

  int32_t          refCount;
  void *           parent;
  void *           idPool;     // handle to ID pool
  void *           tmrCtrl;    // handle to timer
  SHashObj *       hash;       // handle returned by hash utility
  void *           tcphandle;  // returned handle from TCP initialization
  void *           udphandle;  // returned handle from UDP initialization
  void *           pCache;     // connection cache
  pthread_mutex_t  mutex;
  struct SRpcConn *connList;  // connection list
} SRpcInfo;

typedef struct {
  SRpcInfo *       pRpc;      // associated SRpcInfo
  SEpSet           epSet;     // ip list provided by app
  void *           ahandle;   // handle provided by app
  struct SRpcConn *pConn;     // pConn allocated
  tmsg_t           msgType;   // message type
  uint8_t *        pCont;     // content provided by app
  int32_t          contLen;   // content length
  int32_t          code;      // error code
  int16_t          numOfTry;  // number of try for different servers
  int8_t           oldInUse;  // server EP inUse passed by app
  int8_t           redirect;  // flag to indicate redirect
  int8_t           connType;  // connection type
  int64_t          rid;       // refId returned by taosAddRef
  SRpcMsg *        pRsp;      // for synchronous API
  tsem_t *         pSem;      // for synchronous API
  SEpSet *         pSet;      // for synchronous API
  char             msg[0];    // RpcHead starts from here
} SRpcReqContext;

#define RPC_MSG_OVERHEAD (sizeof(SRpcReqContext) + sizeof(SRpcHead) + sizeof(SRpcDigest))
#define rpcHeadFromCont(cont) ((SRpcHead *)((char *)cont - sizeof(SRpcHead)))
#define rpcContFromHead(msg) (msg + sizeof(SRpcHead))
#define rpcMsgLenFromCont(contLen) (contLen + sizeof(SRpcHead))
#define rpcContLenFromMsg(msgLen) (msgLen - sizeof(SRpcHead))
#define rpcIsReq(type) (type & 1U)

typedef struct SRpcConn {
  char            info[48];                   // debug info: label + pConn + ahandle
  int             sid;                        // session ID
  uint32_t        ownId;                      // own link ID
  uint32_t        peerId;                     // peer link ID
  char            user[TSDB_UNI_LEN];         // user ID for the link
  char            spi;                        // security parameter index
  char            encrypt;                    // encryption, 0:1
  char            secret[TSDB_PASSWORD_LEN];  // secret for the link
  char            ckey[TSDB_PASSWORD_LEN];    // ciphering key
  char            secured;                    // if set to 1, no authentication
  uint16_t        localPort;                  // for UDP only
  uint32_t        linkUid;                    // connection unique ID assigned by client
  uint32_t        peerIp;                     // peer IP
  uint16_t        peerPort;                   // peer port
  char            peerFqdn[TSDB_FQDN_LEN];    // peer FQDN or ip string
  uint16_t        tranId;                     // outgoing transcation ID, for build message
  uint16_t        outTranId;                  // outgoing transcation ID
  uint16_t        inTranId;                   // transcation ID for incoming msg
  tmsg_t          outType;                    // message type for outgoing request
  tmsg_t          inType;                     // message type for incoming request
  void *          chandle;                    // handle passed by TCP/UDP connection layer
  void *          ahandle;                    // handle provided by upper app layter
  int             retry;                      // number of retry for sending request
  int             tretry;                     // total retry
  void *          pTimer;                     // retry timer to monitor the response
  void *          pIdleTimer;                 // idle timer
  char *          pRspMsg;                    // response message including header
  int             rspMsgLen;                  // response messag length
  char *          pReqMsg;                    // request message including header
  int             reqMsgLen;                  // request message length
  SRpcInfo *      pRpc;                       // the associated SRpcInfo
  int8_t          connType;                   // connection type
  int64_t         lockedBy;                   // lock for connection
  SRpcReqContext *pContext;                   // request context
} SRpcConn;

static int     tsRpcRefId = -1;
static int32_t tsRpcNum = 0;
// static pthread_once_t tsRpcInit = PTHREAD_ONCE_INIT;

// server:0 client:1  tcp:2 udp:0
#define RPC_CONN_UDPS 0
#define RPC_CONN_UDPC 1
#define RPC_CONN_TCPS 2
#define RPC_CONN_TCPC 3

void *(*taosInitConn[])(uint32_t ip, uint16_t port, char *label, int threads, void *fp, void *shandle) = {
    taosInitUdpConnection, taosInitUdpConnection, taosInitTcpServer, taosInitTcpClient};

void (*taosCleanUpConn[])(void *thandle) = {taosCleanUpUdpConnection, taosCleanUpUdpConnection, taosCleanUpTcpServer,
                                            taosCleanUpTcpClient};

void (*taosStopConn[])(void *thandle) = {
    taosStopUdpConnection,
    taosStopUdpConnection,
    taosStopTcpServer,
    taosStopTcpClient,
};

int (*taosSendData[])(uint32_t ip, uint16_t port, void *data, int len, void *chandle) = {
    taosSendUdpData, taosSendUdpData, taosSendTcpData, taosSendTcpData};

void *(*taosOpenConn[])(void *shandle, void *thandle, uint32_t ip, uint16_t port) = {
    taosOpenUdpConnection,
    taosOpenUdpConnection,
    NULL,
    taosOpenTcpClientConnection,
};

void (*taosCloseConn[])(void *chandle) = {NULL, NULL, taosCloseTcpConnection, taosCloseTcpConnection};

static SRpcConn *rpcOpenConn(SRpcInfo *pRpc, char *peerFqdn, uint16_t peerPort, int8_t connType);
static void      rpcCloseConn(void *thandle);
static SRpcConn *rpcSetupConnToServer(SRpcReqContext *pContext);
static SRpcConn *rpcAllocateClientConn(SRpcInfo *pRpc);
static SRpcConn *rpcAllocateServerConn(SRpcInfo *pRpc, SRecvInfo *pRecv);
static SRpcConn *rpcGetConnObj(SRpcInfo *pRpc, int sid, SRecvInfo *pRecv);

static void rpcSendReqToServer(SRpcInfo *pRpc, SRpcReqContext *pContext);
static void rpcSendQuickRsp(SRpcConn *pConn, int32_t code);
static void rpcSendErrorMsgToPeer(SRecvInfo *pRecv, int32_t code);
static void rpcSendMsgToPeer(SRpcConn *pConn, void *data, int dataLen);
static void rpcSendReqHead(SRpcConn *pConn);

static void *rpcProcessMsgFromPeer(SRecvInfo *pRecv);
static void  rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead, SRpcReqContext *pContext);
static void  rpcProcessConnError(void *param, void *id);
static void  rpcProcessRetryTimer(void *, void *);
static void  rpcProcessIdleTimer(void *param, void *tmrId);
static void  rpcProcessProgressTimer(void *param, void *tmrId);

static void      rpcFreeMsg(void *msg);
static int32_t   rpcCompressRpcMsg(char *pCont, int32_t contLen);
static SRpcHead *rpcDecompressRpcMsg(SRpcHead *pHead);
static int       rpcAddAuthPart(SRpcConn *pConn, char *msg, int msgLen);
static int       rpcCheckAuthentication(SRpcConn *pConn, char *msg, int msgLen);
static void      rpcLockConn(SRpcConn *pConn);
static void      rpcUnlockConn(SRpcConn *pConn);
static void      rpcAddRef(SRpcInfo *pRpc);
static void      rpcDecRef(SRpcInfo *pRpc);

static void rpcFree(void *p) {
  tTrace("free mem: %p", p);
  free(p);
}

static void rpcInitImp(void) {
  tsProgressTimer = tsRpcTimer / 2;
  tsRpcMaxRetry = tsRpcMaxTime * 1000 / tsProgressTimer;
  tsRpcHeadSize = RPC_MSG_OVERHEAD;
  tsRpcOverhead = sizeof(SRpcReqContext);

  tsRpcRefId = taosOpenRef(200, rpcFree);
}

int32_t rpcInit(void) {
  pthread_once(&tsRpcInitOnce, rpcInitImp);
  return 0;
}

void rpcCleanup(void) {
  taosCloseRef(tsRpcRefId);
  tsRpcRefId = -1;
}

void *rpcOpen(const SRpcInit *pInit) {
  SRpcInfo *pRpc;

  // pthread_once(&tsRpcInit, rpcInit);

  pRpc = (SRpcInfo *)calloc(1, sizeof(SRpcInfo));
  if (pRpc == NULL) return NULL;

  if (pInit->label) tstrncpy(pRpc->label, pInit->label, strlen(pInit->label));

  pRpc->connType = pInit->connType;
  if (pRpc->connType == TAOS_CONN_CLIENT) {
    pRpc->numOfThreads = pInit->numOfThreads;
  } else {
    pRpc->numOfThreads = pInit->numOfThreads > TSDB_MAX_RPC_THREADS ? TSDB_MAX_RPC_THREADS : pInit->numOfThreads;
  }
  pRpc->idleTime = pInit->idleTime;
  pRpc->localPort = pInit->localPort;
  pRpc->afp = pInit->afp;
  pRpc->sessions = pInit->sessions + 1;
  if (pInit->user) tstrncpy(pRpc->user, pInit->user, sizeof(pRpc->user));
  if (pInit->secret) memcpy(pRpc->secret, pInit->secret, sizeof(pRpc->secret));
  if (pInit->ckey) tstrncpy(pRpc->ckey, pInit->ckey, sizeof(pRpc->ckey));
  pRpc->spi = pInit->spi;
  pRpc->cfp = pInit->cfp;
  pRpc->afp = pInit->afp;
  pRpc->parent = pInit->parent;
  pRpc->refCount = 1;

  atomic_add_fetch_32(&tsRpcNum, 1);

  size_t size = sizeof(SRpcConn) * pRpc->sessions;
  pRpc->connList = (SRpcConn *)calloc(1, size);
  if (pRpc->connList == NULL) {
    tError("%s failed to allocate memory for taos connections, size:%" PRId64, pRpc->label, (int64_t)size);
    rpcClose(pRpc);
    return NULL;
  }

  pRpc->idPool = taosInitIdPool(pRpc->sessions - 1);
  if (pRpc->idPool == NULL) {
    tError("%s failed to init ID pool", pRpc->label);
    rpcClose(pRpc);
    return NULL;
  }

  pRpc->tmrCtrl = taosTmrInit(pRpc->sessions * 2 + 1, 50, 10000, pRpc->label);
  if (pRpc->tmrCtrl == NULL) {
    tError("%s failed to init timers", pRpc->label);
    rpcClose(pRpc);
    return NULL;
  }

  if (pRpc->connType == TAOS_CONN_SERVER) {
    pRpc->hash = taosHashInit(pRpc->sessions, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, true);
    if (pRpc->hash == NULL) {
      tError("%s failed to init string hash", pRpc->label);
      rpcClose(pRpc);
      return NULL;
    }
  } else {
    pRpc->pCache = rpcOpenConnCache(pRpc->sessions, rpcCloseConn, pRpc->tmrCtrl, pRpc->idleTime * 20);
    if (pRpc->pCache == NULL) {
      tError("%s failed to init connection cache", pRpc->label);
      rpcClose(pRpc);
      return NULL;
    }
  }

  pthread_mutex_init(&pRpc->mutex, NULL);

  pRpc->tcphandle = (*taosInitConn[pRpc->connType | RPC_CONN_TCP])(0, pRpc->localPort, pRpc->label, pRpc->numOfThreads,
                                                                   rpcProcessMsgFromPeer, pRpc);
  pRpc->udphandle =
      (*taosInitConn[pRpc->connType])(0, pRpc->localPort, pRpc->label, pRpc->numOfThreads, rpcProcessMsgFromPeer, pRpc);

  if (pRpc->tcphandle == NULL || pRpc->udphandle == NULL) {
    tError("%s failed to init network, port:%d", pRpc->label, pRpc->localPort);
    rpcClose(pRpc);
    return NULL;
  }

  tDebug("%s rpc is opened, threads:%d sessions:%d", pRpc->label, pRpc->numOfThreads, pInit->sessions);

  return pRpc;
}

void rpcClose(void *param) {
  SRpcInfo *pRpc = (SRpcInfo *)param;

  // stop connection to outside first
  (*taosStopConn[pRpc->connType | RPC_CONN_TCP])(pRpc->tcphandle);
  (*taosStopConn[pRpc->connType])(pRpc->udphandle);

  // close all connections
  for (int i = 0; i < pRpc->sessions; ++i) {
    if (pRpc->connList && pRpc->connList[i].user[0]) {
      rpcCloseConn((void *)(pRpc->connList + i));
    }
  }

  // clean up
  (*taosCleanUpConn[pRpc->connType | RPC_CONN_TCP])(pRpc->tcphandle);
  (*taosCleanUpConn[pRpc->connType])(pRpc->udphandle);

  tDebug("%s rpc is closed", pRpc->label);
  rpcDecRef(pRpc);
}

void *rpcMallocCont(int contLen) {
  int size = contLen + RPC_MSG_OVERHEAD;

  char *start = (char *)calloc(1, (size_t)size);
  if (start == NULL) {
    tError("failed to malloc msg, size:%d", size);
    return NULL;
  } else {
    tTrace("malloc mem:%p size:%d", start, size);
  }

  return start + sizeof(SRpcReqContext) + sizeof(SRpcHead);
}

void rpcFreeCont(void *cont) {
  if (cont) {
    char *temp = ((char *)cont) - sizeof(SRpcHead) - sizeof(SRpcReqContext);
    free(temp);
    tTrace("free mem: %p", temp);
  }
}

void *rpcReallocCont(void *ptr, int contLen) {
  if (ptr == NULL) return rpcMallocCont(contLen);

  char *start = ((char *)ptr) - sizeof(SRpcReqContext) - sizeof(SRpcHead);
  if (contLen == 0) {
    free(start);
    return NULL;
  }

  int size = contLen + RPC_MSG_OVERHEAD;
  start = realloc(start, size);
  if (start == NULL) {
    tError("failed to realloc cont, size:%d", size);
    return NULL;
  }

  return start + sizeof(SRpcReqContext) + sizeof(SRpcHead);
}

void rpcSendRequest(void *shandle, const SEpSet *pEpSet, SRpcMsg *pMsg, int64_t *pRid) {
  SRpcInfo *      pRpc = (SRpcInfo *)shandle;
  SRpcReqContext *pContext;

  int contLen = rpcCompressRpcMsg(pMsg->pCont, pMsg->contLen);
  pContext = (SRpcReqContext *)((char *)pMsg->pCont - sizeof(SRpcHead) - sizeof(SRpcReqContext));
  pContext->ahandle = pMsg->ahandle;
  pContext->pRpc = (SRpcInfo *)shandle;
  pContext->epSet = *pEpSet;
  pContext->contLen = contLen;
  pContext->pCont = pMsg->pCont;
  pContext->msgType = pMsg->msgType;
  pContext->oldInUse = pEpSet->inUse;

  pContext->connType = RPC_CONN_UDPC;
  if (contLen > tsRpcMaxUdpSize || tsRpcForceTcp) pContext->connType = RPC_CONN_TCPC;

  // connection type is application specific.
  // for TDengine, all the query, show commands shall have TCP connection
  tmsg_t type = pMsg->msgType;
  if (type == TDMT_VND_QUERY || type == TDMT_MND_SHOW_RETRIEVE || type == TDMT_VND_FETCH ||
      type == TDMT_MND_VGROUP_LIST || type == TDMT_VND_TABLES_META || type == TDMT_VND_TABLE_META ||
      type == TDMT_MND_SHOW || type == TDMT_MND_STATUS || type == TDMT_VND_ALTER_TABLE)
    pContext->connType = RPC_CONN_TCPC;

  pContext->rid = taosAddRef(tsRpcRefId, pContext);
  if (pRid) *pRid = pContext->rid;

  rpcSendReqToServer(pRpc, pContext);
}

void rpcSendResponse(const SRpcMsg *pRsp) {
  if (pRsp->handle == NULL) return;

  int       msgLen = 0;
  SRpcConn *pConn = (SRpcConn *)pRsp->handle;
  SRpcMsg   rpcMsg = *pRsp;
  SRpcMsg * pMsg = &rpcMsg;
  SRpcInfo *pRpc = pConn->pRpc;

  if (pMsg->pCont == NULL) {
    pMsg->pCont = rpcMallocCont(0);
    pMsg->contLen = 0;
  }

  SRpcHead *pHead = rpcHeadFromCont(pMsg->pCont);
  char *    msg = (char *)pHead;

  pMsg->contLen = rpcCompressRpcMsg(pMsg->pCont, pMsg->contLen);
  msgLen = rpcMsgLenFromCont(pMsg->contLen);

  rpcLockConn(pConn);

  if (pConn->inType == 0 || pConn->user[0] == 0) {
    tError("%s, connection is already released, rsp wont be sent", pConn->info);
    rpcUnlockConn(pConn);
    rpcFreeCont(pMsg->pCont);
    rpcDecRef(pRpc);
    return;
  }

  // set msg header
  pHead->version = 1;
  pHead->msgType = pConn->inType + 1;
  pHead->spi = pConn->spi;
  pHead->encrypt = pConn->encrypt;
  pHead->tranId = pConn->inTranId;
  pHead->sourceId = pConn->ownId;
  pHead->destId = pConn->peerId;
  pHead->linkUid = pConn->linkUid;
  pHead->port = htons(pConn->localPort);
  pHead->code = htonl(pMsg->code);
  pHead->ahandle = (uint64_t)pConn->ahandle;

  // set pConn parameters
  pConn->inType = 0;

  // response message is released until new response is sent
  rpcFreeMsg(pConn->pRspMsg);
  pConn->pRspMsg = msg;
  pConn->rspMsgLen = msgLen;
  if (pMsg->code == TSDB_CODE_RPC_ACTION_IN_PROGRESS) pConn->inTranId--;

  // stop the progress timer
  taosTmrStopA(&pConn->pTimer);

  // set the idle timer to monitor the activity
  taosTmrReset(rpcProcessIdleTimer, pRpc->idleTime * 30, pConn, pRpc->tmrCtrl, &pConn->pIdleTimer);
  rpcSendMsgToPeer(pConn, msg, msgLen);

  // if not set to secured, set it expcet NOT_READY case, since client wont treat it as secured
  if (pConn->secured == 0 && pMsg->code != TSDB_CODE_RPC_NOT_READY) pConn->secured = 1;  // connection shall be secured

  if (pConn->pReqMsg) rpcFreeCont(pConn->pReqMsg);
  pConn->pReqMsg = NULL;
  pConn->reqMsgLen = 0;

  rpcUnlockConn(pConn);
  rpcDecRef(pRpc);  // decrease the referene count

  return;
}

void rpcSendRedirectRsp(void *thandle, const SEpSet *pEpSet) {
  SRpcMsg rpcMsg;
  memset(&rpcMsg, 0, sizeof(rpcMsg));

  rpcMsg.contLen = sizeof(SEpSet);
  rpcMsg.pCont = rpcMallocCont(rpcMsg.contLen);
  if (rpcMsg.pCont == NULL) return;

  memcpy(rpcMsg.pCont, pEpSet, sizeof(SEpSet));

  rpcMsg.code = TSDB_CODE_RPC_REDIRECT;
  rpcMsg.handle = thandle;

  rpcSendResponse(&rpcMsg);

  return;
}

int rpcGetConnInfo(void *thandle, SRpcConnInfo *pInfo) {
  SRpcConn *pConn = (SRpcConn *)thandle;
  if (pConn->user[0] == 0) return -1;

  pInfo->clientIp = pConn->peerIp;
  pInfo->clientPort = pConn->peerPort;
  // pInfo->serverIp = pConn->destIp;

  tstrncpy(pInfo->user, pConn->user, sizeof(pInfo->user));
  return 0;
}

void rpcSendRecv(void *shandle, SEpSet *pEpSet, SRpcMsg *pMsg, SRpcMsg *pRsp) {
  SRpcReqContext *pContext;
  pContext = (SRpcReqContext *)((char *)pMsg->pCont - sizeof(SRpcHead) - sizeof(SRpcReqContext));

  memset(pRsp, 0, sizeof(SRpcMsg));

  tsem_t sem;
  tsem_init(&sem, 0, 0);
  pContext->pSem = &sem;
  pContext->pRsp = pRsp;
  pContext->pSet = pEpSet;

  rpcSendRequest(shandle, pEpSet, pMsg, NULL);

  tsem_wait(&sem);
  tsem_destroy(&sem);

  return;
}

// this API is used by server app to keep an APP context in case connection is broken
int rpcReportProgress(void *handle, char *pCont, int contLen) {
  SRpcConn *pConn = (SRpcConn *)handle;
  int       code = 0;

  rpcLockConn(pConn);

  if (pConn->user[0]) {
    // pReqMsg and reqMsgLen is re-used to store the context from app server
    pConn->pReqMsg = pCont;
    pConn->reqMsgLen = contLen;
  } else {
    tDebug("%s, rpc connection is already released", pConn->info);
    rpcFreeCont(pCont);
    code = -1;
  }

  rpcUnlockConn(pConn);
  return code;
}

void rpcCancelRequest(int64_t rid) {
  SRpcReqContext *pContext = taosAcquireRef(tsRpcRefId, rid);
  if (pContext == NULL) return;

  rpcCloseConn(pContext->pConn);

  taosReleaseRef(tsRpcRefId, rid);
}

static void rpcFreeMsg(void *msg) {
  if (msg) {
    char *temp = (char *)msg - sizeof(SRpcReqContext);
    free(temp);
    tTrace("free mem: %p", temp);
  }
}

static SRpcConn *rpcOpenConn(SRpcInfo *pRpc, char *peerFqdn, uint16_t peerPort, int8_t connType) {
  SRpcConn *pConn;

  uint32_t peerIp = taosGetIpv4FromFqdn(peerFqdn);
  if (peerIp == 0xFFFFFFFF) {
    tError("%s, failed to resolve FQDN:%s", pRpc->label, peerFqdn);
    terrno = TSDB_CODE_RPC_FQDN_ERROR;
    return NULL;
  }

  pConn = rpcAllocateClientConn(pRpc);

  if (pConn) {
    tstrncpy(pConn->peerFqdn, peerFqdn, sizeof(pConn->peerFqdn));
    pConn->peerIp = peerIp;
    pConn->peerPort = peerPort;
    tstrncpy(pConn->user, pRpc->user, sizeof(pConn->user));
    pConn->connType = connType;

    if (taosOpenConn[connType]) {
      void *shandle = (connType & RPC_CONN_TCP) ? pRpc->tcphandle : pRpc->udphandle;
      pConn->chandle = (*taosOpenConn[connType])(shandle, pConn, pConn->peerIp, pConn->peerPort);
      if (pConn->chandle == NULL) {
        tError("failed to connect to:%s:%d", taosIpStr(pConn->peerIp), pConn->peerPort);

        terrno = TSDB_CODE_RPC_NETWORK_UNAVAIL;
        rpcCloseConn(pConn);
        pConn = NULL;
      }
    }
  }

  return pConn;
}

static void rpcReleaseConn(SRpcConn *pConn) {
  SRpcInfo *pRpc = pConn->pRpc;
  if (pConn->user[0] == 0) return;

  pConn->user[0] = 0;
  if (taosCloseConn[pConn->connType]) (*taosCloseConn[pConn->connType])(pConn->chandle);

  taosTmrStopA(&pConn->pTimer);
  taosTmrStopA(&pConn->pIdleTimer);

  if (pRpc->connType == TAOS_CONN_SERVER) {
    char   hashstr[40] = {0};
    size_t size = snprintf(hashstr, sizeof(hashstr), "%x:%x:%x:%d", pConn->peerIp, pConn->linkUid, pConn->peerId,
                           pConn->connType);
    taosHashRemove(pRpc->hash, hashstr, size);
    rpcFreeMsg(pConn->pRspMsg);  // it may have a response msg saved, but not request msg
    pConn->pRspMsg = NULL;

    // if server has ever reported progress, free content
    if (pConn->pReqMsg) rpcFreeCont(pConn->pReqMsg);  // do not use rpcFreeMsg
  } else {
    // if there is an outgoing message, free it
    if (pConn->outType && pConn->pReqMsg) {
      SRpcReqContext *pContext = pConn->pContext;
      if (pContext) {
        if (pContext->pRsp) {
          // for synchronous API, post semaphore to unblock app
          pContext->pRsp->code = TSDB_CODE_RPC_APP_ERROR;
          pContext->pRsp->pCont = NULL;
          pContext->pRsp->contLen = 0;
          tsem_post(pContext->pSem);
        }
        pContext->pConn = NULL;
        taosRemoveRef(tsRpcRefId, pContext->rid);
      } else {
        assert(0);
      }
    }
  }

  // memset could not be used, since lockeBy can not be reset
  pConn->inType = 0;
  pConn->outType = 0;
  pConn->inTranId = 0;
  pConn->outTranId = 0;
  pConn->secured = 0;
  pConn->peerId = 0;
  pConn->peerIp = 0;
  pConn->peerPort = 0;
  pConn->pReqMsg = NULL;
  pConn->reqMsgLen = 0;
  pConn->pContext = NULL;
  pConn->chandle = NULL;

  taosFreeId(pRpc->idPool, pConn->sid);
  tDebug("%s, rpc connection is released", pConn->info);
}

static void rpcCloseConn(void *thandle) {
  SRpcConn *pConn = (SRpcConn *)thandle;
  if (pConn == NULL) return;

  rpcLockConn(pConn);

  if (pConn->user[0]) rpcReleaseConn(pConn);

  rpcUnlockConn(pConn);
}

static SRpcConn *rpcAllocateClientConn(SRpcInfo *pRpc) {
  SRpcConn *pConn = NULL;

  int sid = taosAllocateId(pRpc->idPool);
  if (sid <= 0) {
    tError("%s maximum number of sessions:%d is reached", pRpc->label, pRpc->sessions);
    terrno = TSDB_CODE_RPC_MAX_SESSIONS;
  } else {
    pConn = pRpc->connList + sid;

    pConn->pRpc = pRpc;
    pConn->sid = sid;
    pConn->tranId = (uint16_t)(taosRand() & 0xFFFF);
    pConn->ownId = htonl(pConn->sid);
    pConn->linkUid = (uint32_t)((int64_t)pConn + taosGetPId() + (int64_t)pConn->tranId);
    pConn->spi = pRpc->spi;
    pConn->encrypt = pRpc->encrypt;
    if (pConn->spi) memcpy(pConn->secret, pRpc->secret, TSDB_PASSWORD_LEN);
    tDebug("%s %p client connection is allocated, uid:0x%x", pRpc->label, pConn, pConn->linkUid);
  }

  return pConn;
}

static SRpcConn *rpcAllocateServerConn(SRpcInfo *pRpc, SRecvInfo *pRecv) {
  SRpcConn *pConn = NULL;
  char      hashstr[40] = {0};
  SRpcHead *pHead = (SRpcHead *)pRecv->msg;

  size_t size =
      snprintf(hashstr, sizeof(hashstr), "%x:%x:%x:%d", pRecv->ip, pHead->linkUid, pHead->sourceId, pRecv->connType);

  // check if it is already allocated
  SRpcConn **ppConn = (SRpcConn **)(taosHashGet(pRpc->hash, hashstr, size));
  if (ppConn) pConn = *ppConn;
  if (pConn) {
    pConn->secured = 0;
    return pConn;
  }

  // if code is not 0, it means it is simple reqhead, just ignore
  if (pHead->code != 0) {
    terrno = TSDB_CODE_RPC_ALREADY_PROCESSED;
    return NULL;
  }

  int sid = taosAllocateId(pRpc->idPool);
  if (sid <= 0) {
    tError("%s maximum number of sessions:%d is reached", pRpc->label, pRpc->sessions);
    terrno = TSDB_CODE_RPC_MAX_SESSIONS;
  } else {
    pConn = pRpc->connList + sid;
    memcpy(pConn->user, pHead->user, tListLen(pConn->user));
    pConn->pRpc = pRpc;
    pConn->sid = sid;
    pConn->tranId = (uint16_t)(rand() & 0xFFFF);
    pConn->ownId = htonl(pConn->sid);
    pConn->linkUid = pHead->linkUid;
    if (pRpc->afp) {
      if (pConn->user[0] == 0) {
        terrno = TSDB_CODE_RPC_AUTH_REQUIRED;
      } else {
        terrno = (*pRpc->afp)(pRpc->parent, pConn->user, &pConn->spi, &pConn->encrypt, pConn->secret, pConn->ckey);
      }

      if (terrno != 0) {
        taosFreeId(pRpc->idPool, sid);  // sid shall be released
        pConn = NULL;
      }
    }
  }

  if (pConn) {
    if (pRecv->connType == RPC_CONN_UDPS && pRpc->numOfThreads > 1) {
      // UDP server, assign to new connection
      pRpc->index = (pRpc->index + 1) % pRpc->numOfThreads;
      pConn->localPort = (pRpc->localPort + pRpc->index);
    }

    taosHashPut(pRpc->hash, hashstr, size, (char *)&pConn, POINTER_BYTES);
    tDebug("%s %p server connection is allocated, uid:0x%x sid:%d key:%s", pRpc->label, pConn, pConn->linkUid, sid,
           hashstr);
  }

  return pConn;
}

static SRpcConn *rpcGetConnObj(SRpcInfo *pRpc, int sid, SRecvInfo *pRecv) {
  SRpcConn *pConn = NULL;
  SRpcHead *pHead = (SRpcHead *)pRecv->msg;

  if (sid) {
    pConn = pRpc->connList + sid;
    if (pConn->user[0] == 0) pConn = NULL;
  }

  if (pConn == NULL) {
    if (pRpc->connType == TAOS_CONN_SERVER) {
      pConn = rpcAllocateServerConn(pRpc, pRecv);
    } else {
      terrno = TSDB_CODE_RPC_UNEXPECTED_RESPONSE;
    }
  }

  if (pConn) {
    if (pConn->linkUid != pHead->linkUid) {
      terrno = TSDB_CODE_RPC_MISMATCHED_LINK_ID;
      tDebug("%s %p %p, linkUid:0x%x is not matched with received:0x%x", pRpc->label, pConn, (void *)pHead->ahandle,
             pConn->linkUid, pHead->linkUid);
      pConn = NULL;
    }
  }

  return pConn;
}

static SRpcConn *rpcSetupConnToServer(SRpcReqContext *pContext) {
  SRpcConn *pConn;
  SRpcInfo *pRpc = pContext->pRpc;
  SEpSet *  pEpSet = &pContext->epSet;

  pConn =
      rpcGetConnFromCache(pRpc->pCache, pEpSet->fqdn[pEpSet->inUse], pEpSet->port[pEpSet->inUse], pContext->connType);
  if (pConn == NULL || pConn->user[0] == 0) {
    pConn = rpcOpenConn(pRpc, pEpSet->fqdn[pEpSet->inUse], pEpSet->port[pEpSet->inUse], pContext->connType);
  }

  if (pConn) {
    pConn->tretry = 0;
    pConn->ahandle = pContext->ahandle;
    snprintf(pConn->info, sizeof(pConn->info), "%s %p %p", pRpc->label, pConn, pConn->ahandle);
    pConn->tretry = 0;
  } else {
    tError("%s %p, failed to set up connection(%s)", pRpc->label, pContext->ahandle, tstrerror(terrno));
  }

  return pConn;
}

static int rpcProcessReqHead(SRpcConn *pConn, SRpcHead *pHead) {
  if (pConn->peerId == 0) {
    pConn->peerId = pHead->sourceId;
  } else {
    if (pConn->peerId != pHead->sourceId) {
      tDebug("%s, source Id is changed, old:0x%08x new:0x%08x", pConn->info, pConn->peerId, pHead->sourceId);
      return TSDB_CODE_RPC_INVALID_VALUE;
    }
  }

  if (pConn->inTranId == pHead->tranId) {
    if (pConn->inType == pHead->msgType) {
      if (pHead->code == 0) {
        tDebug("%s, %s is retransmitted", pConn->info, TMSG_INFO(pHead->msgType));
        rpcSendQuickRsp(pConn, TSDB_CODE_RPC_ACTION_IN_PROGRESS);
      } else {
        // do nothing, it is heart beat from client
      }
    } else if (pConn->inType == 0) {
      tDebug("%s, %s is already processed, tranId:%d", pConn->info, TMSG_INFO(pHead->msgType), pConn->inTranId);
      rpcSendMsgToPeer(pConn, pConn->pRspMsg, pConn->rspMsgLen);  // resend the response
    } else {
      tDebug("%s, mismatched message %s and tranId", pConn->info, TMSG_INFO(pHead->msgType));
    }

    // do not reply any message
    return TSDB_CODE_RPC_ALREADY_PROCESSED;
  }

  if (pConn->inType != 0) {
    tDebug("%s, last session is not finished, inTranId:%d tranId:%d", pConn->info, pConn->inTranId, pHead->tranId);
    return TSDB_CODE_RPC_LAST_SESSION_NOT_FINISHED;
  }

  if (rpcContLenFromMsg(pHead->msgLen) <= 0) {
    tDebug("%s, message body is empty, ignore", pConn->info);
    return TSDB_CODE_RPC_APP_ERROR;
  }

  pConn->inTranId = pHead->tranId;
  pConn->inType = pHead->msgType;

  // start the progress timer to monitor the response from server app
  if (pConn->connType != RPC_CONN_TCPS)
    pConn->pTimer = taosTmrStart(rpcProcessProgressTimer, tsProgressTimer, pConn, pConn->pRpc->tmrCtrl);

  return 0;
}

static int rpcProcessRspHead(SRpcConn *pConn, SRpcHead *pHead) {
  SRpcInfo *pRpc = pConn->pRpc;
  pConn->peerId = pHead->sourceId;

  if (pConn->outType == 0 || pConn->pContext == NULL) {
    return TSDB_CODE_RPC_UNEXPECTED_RESPONSE;
  }

  if (pHead->tranId != pConn->outTranId) {
    return TSDB_CODE_RPC_INVALID_TRAN_ID;
  }

  if (pHead->msgType != pConn->outType + 1) {
    return TSDB_CODE_RPC_INVALID_RESPONSE_TYPE;
  }

  taosTmrStopA(&pConn->pTimer);
  pConn->retry = 0;

  if (pHead->code == TSDB_CODE_RPC_AUTH_REQUIRED && pRpc->spi) {
    tDebug("%s, authentication shall be restarted", pConn->info);
    pConn->secured = 0;
    rpcSendMsgToPeer(pConn, pConn->pReqMsg, pConn->reqMsgLen);
    if (pConn->connType != RPC_CONN_TCPC)
      pConn->pTimer = taosTmrStart(rpcProcessRetryTimer, tsRpcTimer, pConn, pRpc->tmrCtrl);
    return TSDB_CODE_RPC_ALREADY_PROCESSED;
  }

  if (pHead->code == TSDB_CODE_RPC_MISMATCHED_LINK_ID) {
    tDebug("%s, mismatched linkUid, link shall be restarted", pConn->info);
    pConn->secured = 0;
    ((SRpcHead *)pConn->pReqMsg)->destId = 0;
    rpcSendMsgToPeer(pConn, pConn->pReqMsg, pConn->reqMsgLen);
    if (pConn->connType != RPC_CONN_TCPC)
      pConn->pTimer = taosTmrStart(rpcProcessRetryTimer, tsRpcTimer, pConn, pRpc->tmrCtrl);
    return TSDB_CODE_RPC_ALREADY_PROCESSED;
  }

  if (pHead->code == TSDB_CODE_RPC_ACTION_IN_PROGRESS) {
    if (pConn->tretry <= tsRpcMaxRetry) {
      tDebug("%s, peer is still processing the transaction, retry:%d", pConn->info, pConn->tretry);
      pConn->tretry++;
      rpcSendReqHead(pConn);
      if (pConn->connType != RPC_CONN_TCPC)
        pConn->pTimer = taosTmrStart(rpcProcessRetryTimer, tsRpcTimer, pConn, pRpc->tmrCtrl);
      return TSDB_CODE_RPC_ALREADY_PROCESSED;
    } else {
      // peer still in processing, give up
      tDebug("%s, server processing takes too long time, give up", pConn->info);
      pHead->code = TSDB_CODE_RPC_TOO_SLOW;
    }
  }

  pConn->outType = 0;
  pConn->pReqMsg = NULL;
  pConn->reqMsgLen = 0;
  SRpcReqContext *pContext = pConn->pContext;

  if (pHead->code == TSDB_CODE_RPC_REDIRECT) {
    if (rpcContLenFromMsg(pHead->msgLen) < sizeof(SEpSet)) {
      // if EpSet is not included in the msg, treat it as NOT_READY
      pHead->code = TSDB_CODE_RPC_NOT_READY;
    } else {
      pContext->redirect++;
      if (pContext->redirect > TSDB_MAX_REPLICA) {
        pHead->code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
        tWarn("%s, too many redirects, quit", pConn->info);
      }
    }
  }

  return TSDB_CODE_SUCCESS;
}

static SRpcConn *rpcProcessMsgHead(SRpcInfo *pRpc, SRecvInfo *pRecv, SRpcReqContext **ppContext) {
  int32_t   sid;
  SRpcConn *pConn = NULL;

  SRpcHead *pHead = (SRpcHead *)pRecv->msg;

  sid = htonl(pHead->destId);
  *ppContext = NULL;

  if (TMSG_INDEX(pHead->msgType) >= TDMT_MAX || TMSG_INDEX(pHead->msgType) <= 0) {
    tDebug("%s sid:%d, invalid message type:%d", pRpc->label, sid, pHead->msgType);
    terrno = TSDB_CODE_RPC_INVALID_MSG_TYPE;
    return NULL;
  }

  if (sid < 0 || sid >= pRpc->sessions) {
    tDebug("%s sid:%d, sid is out of range, max sid:%d, %s discarded", pRpc->label, sid, pRpc->sessions,
           TMSG_INFO(pHead->msgType));
    terrno = TSDB_CODE_RPC_INVALID_SESSION_ID;
    return NULL;
  }

  if (rpcIsReq(pHead->msgType) && htonl(pHead->msgVer) != tsVersion >> 8) {
    tDebug("%s sid:%d, invalid client version:%x/%x %s", pRpc->label, sid, htonl(pHead->msgVer), tsVersion,
           TMSG_INFO(pHead->msgType));
    terrno = TSDB_CODE_RPC_INVALID_VERSION;
    return NULL;
  }

  pConn = rpcGetConnObj(pRpc, sid, pRecv);
  if (pConn == NULL) {
    tDebug("%s %p, failed to get connection obj(%s)", pRpc->label, (void *)pHead->ahandle, tstrerror(terrno));
    return NULL;
  }

  rpcLockConn(pConn);

  if (rpcIsReq(pHead->msgType)) {
    pConn->ahandle = (void *)pHead->ahandle;
    snprintf(pConn->info, sizeof(pConn->info), "%s %p %p", pRpc->label, pConn, pConn->ahandle);
  }

  sid = pConn->sid;
  if (pConn->chandle == NULL) pConn->chandle = pRecv->chandle;
  pConn->peerIp = pRecv->ip;
  pConn->peerPort = pRecv->port;
  if (pHead->port) pConn->peerPort = htons(pHead->port);

  terrno = rpcCheckAuthentication(pConn, (char *)pHead, pRecv->msgLen);

  // code can be transformed only after authentication
  pHead->code = htonl(pHead->code);

  if (terrno == 0) {
    if (pHead->encrypt) {
      // decrypt here
    }

    if (rpcIsReq(pHead->msgType)) {
      pConn->connType = pRecv->connType;
      terrno = rpcProcessReqHead(pConn, pHead);

      // stop idle timer
      taosTmrStopA(&pConn->pIdleTimer);

      // client shall send the request within tsRpcTime again for UDP, double it
      if (pConn->connType != RPC_CONN_TCPS)
        pConn->pIdleTimer = taosTmrStart(rpcProcessIdleTimer, tsRpcTimer * 2, pConn, pRpc->tmrCtrl);
    } else {
      terrno = rpcProcessRspHead(pConn, pHead);
      *ppContext = pConn->pContext;
    }
  }

  rpcUnlockConn(pConn);

  return pConn;
}

static void doRpcReportBrokenLinkToServer(void *param, void *id) {
  SRpcMsg * pRpcMsg = (SRpcMsg *)(param);
  SRpcConn *pConn = (SRpcConn *)(pRpcMsg->handle);
  SRpcInfo *pRpc = pConn->pRpc;
  (*(pRpc->cfp))(pRpc->parent, pRpcMsg, NULL);
  free(pRpcMsg);
}
static void rpcReportBrokenLinkToServer(SRpcConn *pConn) {
  SRpcInfo *pRpc = pConn->pRpc;
  if (pConn->pReqMsg == NULL) return;

  // if there are pending request, notify the app
  rpcAddRef(pRpc);
  tDebug("%s, notify the server app, connection is gone", pConn->info);

  SRpcMsg *rpcMsg = malloc(sizeof(SRpcMsg));
  rpcMsg->pCont = pConn->pReqMsg;      // pReqMsg is re-used to store the APP context from server
  rpcMsg->contLen = pConn->reqMsgLen;  // reqMsgLen is re-used to store the APP context length
  rpcMsg->ahandle = pConn->ahandle;
  rpcMsg->handle = pConn;
  rpcMsg->msgType = pConn->inType;
  rpcMsg->code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
  pConn->pReqMsg = NULL;
  pConn->reqMsgLen = 0;
  if (pRpc->cfp) {
    taosTmrStart(doRpcReportBrokenLinkToServer, 0, rpcMsg, pRpc->tmrCtrl);
  } else {
    free(rpcMsg);
  }
}

static void rpcProcessBrokenLink(SRpcConn *pConn) {
  if (pConn == NULL) return;
  SRpcInfo *pRpc = pConn->pRpc;
  tDebug("%s, link is broken", pConn->info);

  rpcLockConn(pConn);

  if (pConn->outType) {
    SRpcReqContext *pContext = pConn->pContext;
    pContext->code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
    pContext->pConn = NULL;
    pConn->pReqMsg = NULL;
    taosTmrStart(rpcProcessConnError, 0, pContext, pRpc->tmrCtrl);
  }

  if (pConn->inType) rpcReportBrokenLinkToServer(pConn);

  rpcReleaseConn(pConn);
  rpcUnlockConn(pConn);
}

static void *rpcProcessMsgFromPeer(SRecvInfo *pRecv) {
  SRpcHead *pHead = (SRpcHead *)pRecv->msg;
  SRpcInfo *pRpc = (SRpcInfo *)pRecv->shandle;
  SRpcConn *pConn = (SRpcConn *)pRecv->thandle;

  tDump(pRecv->msg, pRecv->msgLen);

  // underlying UDP layer does not know it is server or client
  pRecv->connType = pRecv->connType | pRpc->connType;

  if (pRecv->msg == NULL) {
    rpcProcessBrokenLink(pConn);
    return NULL;
  }

  terrno = 0;
  SRpcReqContext *pContext;
  pConn = rpcProcessMsgHead(pRpc, pRecv, &pContext);

  char ipstr[24] = {0};
  taosIpPort2String(pRecv->ip, pRecv->port, ipstr);

  if (TMSG_INDEX(pHead->msgType) >= 1 && TMSG_INDEX(pHead->msgType) < TDMT_MAX) {
    tDebug("%s %p %p, %s received from %s, parse code:0x%x len:%d sig:0x%08x:0x%08x:%d code:0x%x", pRpc->label, pConn,
           (void *)pHead->ahandle, TMSG_INFO(pHead->msgType), ipstr, terrno, pRecv->msgLen, pHead->sourceId,
           pHead->destId, pHead->tranId, pHead->code);
  } else {
    tDebug("%s %p %p, %d received from %s, parse code:0x%x len:%d sig:0x%08x:0x%08x:%d code:0x%x", pRpc->label, pConn,
           (void *)pHead->ahandle, pHead->msgType, ipstr, terrno, pRecv->msgLen, pHead->sourceId, pHead->destId,
           pHead->tranId, pHead->code);
  }

  int32_t code = terrno;
  if (code != TSDB_CODE_RPC_ALREADY_PROCESSED) {
    if (code != 0) {  // parsing error
      if (rpcIsReq(pHead->msgType)) {
        rpcSendErrorMsgToPeer(pRecv, code);
        if (code == TSDB_CODE_RPC_INVALID_TIME_STAMP || code == TSDB_CODE_RPC_AUTH_FAILURE) {
          rpcCloseConn(pConn);
        }
        if (TMSG_INDEX(pHead->msgType) + 1 > 1 && TMSG_INDEX(pHead->msgType) + 1 < TDMT_MAX) {
          tDebug("%s %p %p, %s is sent with error code:0x%x", pRpc->label, pConn, (void *)pHead->ahandle,
                 TMSG_INFO(pHead->msgType + 1), code);
        } else {
          tError("%s %p %p, %s is sent with error code:0x%x", pRpc->label, pConn, (void *)pHead->ahandle,
                 TMSG_INFO(pHead->msgType), code);
        }
      }
    } else {  // msg is passed to app only parsing is ok
      rpcProcessIncomingMsg(pConn, pHead, pContext);
    }
  }

  if (code) rpcFreeMsg(pRecv->msg);  // parsing failed, msg shall be freed
  return pConn;
}

static void rpcNotifyClient(SRpcReqContext *pContext, SRpcMsg *pMsg) {
  SRpcInfo *pRpc = pContext->pRpc;

  pContext->pConn = NULL;
  if (pContext->pRsp) {
    // for synchronous API
    memcpy(pContext->pSet, &pContext->epSet, sizeof(SEpSet));
    memcpy(pContext->pRsp, pMsg, sizeof(SRpcMsg));
    tsem_post(pContext->pSem);
  } else {
    // for asynchronous API
    SEpSet *pEpSet = NULL;
    if (pContext->epSet.inUse != pContext->oldInUse || pContext->redirect) pEpSet = &pContext->epSet;

    (*pRpc->cfp)(pRpc->parent, pMsg, pEpSet);
  }

  // free the request message
  taosRemoveRef(tsRpcRefId, pContext->rid);
}

static void rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead, SRpcReqContext *pContext) {
  SRpcInfo *pRpc = pConn->pRpc;
  SRpcMsg   rpcMsg;

  pHead = rpcDecompressRpcMsg(pHead);
  rpcMsg.contLen = rpcContLenFromMsg(pHead->msgLen);
  rpcMsg.pCont = pHead->content;
  rpcMsg.msgType = pHead->msgType;
  rpcMsg.code = pHead->code;

  if (rpcIsReq(pHead->msgType)) {
    rpcMsg.ahandle = pConn->ahandle;
    rpcMsg.handle = pConn;
    rpcAddRef(pRpc);  // add the refCount for requests

    // notify the server app
    (*(pRpc->cfp))(pRpc->parent, &rpcMsg, NULL);
  } else {
    // it's a response
    rpcMsg.handle = pContext;
    rpcMsg.ahandle = pContext->ahandle;
    pContext->pConn = NULL;

    // for UDP, port may be changed by server, the port in epSet shall be used for cache
    if (pHead->code != TSDB_CODE_RPC_TOO_SLOW) {
      rpcAddConnIntoCache(pRpc->pCache, pConn, pConn->peerFqdn, pContext->epSet.port[pContext->epSet.inUse],
                          pConn->connType);
    } else {
      rpcCloseConn(pConn);
    }

    if (pHead->code == TSDB_CODE_RPC_REDIRECT) {
      pContext->numOfTry = 0;
      SEpSet *pEpSet = (SEpSet *)pHead->content;
      if (pEpSet->numOfEps > 0) {
        memcpy(&pContext->epSet, pHead->content, sizeof(pContext->epSet));
        tDebug("%s, redirect is received, numOfEps:%d inUse:%d", pConn->info, pContext->epSet.numOfEps,
               pContext->epSet.inUse);
        for (int i = 0; i < pContext->epSet.numOfEps; ++i) {
          pContext->epSet.port[i] = htons(pContext->epSet.port[i]);
          tDebug("%s, redirect is received, index:%d ep:%s:%u", pConn->info, i, pContext->epSet.fqdn[i],
                 pContext->epSet.port[i]);
        }
      }
      rpcSendReqToServer(pRpc, pContext);
      rpcFreeCont(rpcMsg.pCont);
    } else if (pHead->code == TSDB_CODE_RPC_NOT_READY || pHead->code == TSDB_CODE_APP_NOT_READY ||
               pHead->code == TSDB_CODE_DND_OFFLINE) {
      pContext->code = pHead->code;
      rpcProcessConnError(pContext, NULL);
      rpcFreeCont(rpcMsg.pCont);
    } else {
      rpcNotifyClient(pContext, &rpcMsg);
    }
  }
}

static void rpcSendQuickRsp(SRpcConn *pConn, int32_t code) {
  char      msg[RPC_MSG_OVERHEAD];
  SRpcHead *pHead;

  // set msg header
  memset(msg, 0, sizeof(SRpcHead));
  pHead = (SRpcHead *)msg;
  pHead->version = 1;
  pHead->msgType = pConn->inType + 1;
  pHead->spi = pConn->spi;
  pHead->encrypt = 0;
  pHead->tranId = pConn->inTranId;
  pHead->sourceId = pConn->ownId;
  pHead->destId = pConn->peerId;
  pHead->linkUid = pConn->linkUid;
  pHead->ahandle = (uint64_t)pConn->ahandle;
  memcpy(pHead->user, pConn->user, tListLen(pHead->user));
  pHead->code = htonl(code);

  rpcSendMsgToPeer(pConn, msg, sizeof(SRpcHead));
  pConn->secured = 1;  // connection shall be secured
}

static void rpcSendReqHead(SRpcConn *pConn) {
  char      msg[RPC_MSG_OVERHEAD];
  SRpcHead *pHead;

  // set msg header
  memset(msg, 0, sizeof(SRpcHead));
  pHead = (SRpcHead *)msg;
  pHead->version = 1;
  pHead->msgType = pConn->outType;
  pHead->msgVer = htonl(tsVersion >> 8);
  pHead->spi = pConn->spi;
  pHead->encrypt = 0;
  pHead->tranId = pConn->outTranId;
  pHead->sourceId = pConn->ownId;
  pHead->destId = pConn->peerId;
  pHead->linkUid = pConn->linkUid;
  pHead->ahandle = (uint64_t)pConn->ahandle;
  memcpy(pHead->user, pConn->user, tListLen(pHead->user));
  pHead->code = 1;

  rpcSendMsgToPeer(pConn, msg, sizeof(SRpcHead));
}

static void rpcSendErrorMsgToPeer(SRecvInfo *pRecv, int32_t code) {
  SRpcHead *pRecvHead, *pReplyHead;
  char      msg[sizeof(SRpcHead) + sizeof(SRpcDigest) + sizeof(uint32_t)];
  uint32_t  timeStamp;
  int       msgLen;

  pRecvHead = (SRpcHead *)pRecv->msg;
  pReplyHead = (SRpcHead *)msg;

  memset(msg, 0, sizeof(SRpcHead));
  pReplyHead->version = pRecvHead->version;
  pReplyHead->msgType = (tmsg_t)(pRecvHead->msgType + 1);
  pReplyHead->spi = 0;
  pReplyHead->encrypt = pRecvHead->encrypt;
  pReplyHead->tranId = pRecvHead->tranId;
  pReplyHead->sourceId = pRecvHead->destId;
  pReplyHead->destId = pRecvHead->sourceId;
  pReplyHead->linkUid = pRecvHead->linkUid;
  pReplyHead->ahandle = pRecvHead->ahandle;

  pReplyHead->code = htonl(code);
  msgLen = sizeof(SRpcHead);

  if (code == TSDB_CODE_RPC_INVALID_TIME_STAMP) {
    // include a time stamp if client's time is not synchronized well
    uint8_t *pContent = pReplyHead->content;
    timeStamp = htonl(taosGetTimestampSec());
    memcpy(pContent, &timeStamp, sizeof(timeStamp));
    msgLen += sizeof(timeStamp);
  }

  pReplyHead->msgLen = (int32_t)htonl((uint32_t)msgLen);
  (*taosSendData[pRecv->connType])(pRecv->ip, pRecv->port, msg, msgLen, pRecv->chandle);

  return;
}

static void rpcSendReqToServer(SRpcInfo *pRpc, SRpcReqContext *pContext) {
  SRpcHead *pHead = rpcHeadFromCont(pContext->pCont);
  char *    msg = (char *)pHead;
  int       msgLen = rpcMsgLenFromCont(pContext->contLen);
  tmsg_t    msgType = pContext->msgType;

  pContext->numOfTry++;
  SRpcConn *pConn = rpcSetupConnToServer(pContext);
  if (pConn == NULL) {
    pContext->code = terrno;
    taosTmrStart(rpcProcessConnError, 1, pContext, pRpc->tmrCtrl);
    return;
  }

  pContext->pConn = pConn;
  pConn->ahandle = pContext->ahandle;
  rpcLockConn(pConn);

  // set the message header
  pHead->version = 1;
  pHead->msgVer = htonl(tsVersion >> 8);
  pHead->msgType = msgType;
  pHead->encrypt = 0;
  pConn->tranId++;
  if (pConn->tranId == 0) pConn->tranId++;
  pHead->tranId = pConn->tranId;
  pHead->sourceId = pConn->ownId;
  pHead->destId = pConn->peerId;
  pHead->port = 0;
  pHead->linkUid = pConn->linkUid;
  pHead->ahandle = (uint64_t)pConn->ahandle;
  memcpy(pHead->user, pConn->user, tListLen(pHead->user));

  // set the connection parameters
  pConn->outType = msgType;
  pConn->outTranId = pHead->tranId;
  pConn->pReqMsg = msg;
  pConn->reqMsgLen = msgLen;
  pConn->pContext = pContext;

  rpcSendMsgToPeer(pConn, msg, msgLen);
  if (pConn->connType != RPC_CONN_TCPC)
    taosTmrReset(rpcProcessRetryTimer, tsRpcTimer, pConn, pRpc->tmrCtrl, &pConn->pTimer);

  rpcUnlockConn(pConn);
}

static void rpcSendMsgToPeer(SRpcConn *pConn, void *msg, int msgLen) {
  int       writtenLen = 0;
  SRpcHead *pHead = (SRpcHead *)msg;

  msgLen = rpcAddAuthPart(pConn, msg, msgLen);

  if (rpcIsReq(pHead->msgType)) {
    tDebug("%s, %s is sent to %s:%hu, len:%d sig:0x%08x:0x%08x:%d", pConn->info, TMSG_INFO(pHead->msgType),
           pConn->peerFqdn, pConn->peerPort, msgLen, pHead->sourceId, pHead->destId, pHead->tranId);
  } else {
    if (pHead->code == 0) pConn->secured = 1;  // for success response, set link as secured
    tDebug("%s, %s is sent to 0x%x:%hu, code:0x%x len:%d sig:0x%08x:0x%08x:%d", pConn->info, TMSG_INFO(pHead->msgType),
           pConn->peerIp, pConn->peerPort, htonl(pHead->code), msgLen, pHead->sourceId, pHead->destId, pHead->tranId);
  }

  // tTrace("connection type is: %d", pConn->connType);
  writtenLen = (*taosSendData[pConn->connType])(pConn->peerIp, pConn->peerPort, pHead, msgLen, pConn->chandle);

  if (writtenLen != msgLen) {
    tError("%s, failed to send, msgLen:%d written:%d, reason:%s", pConn->info, msgLen, writtenLen, strerror(errno));
  }

  tDump(msg, msgLen);
}

static void rpcProcessConnError(void *param, void *id) {
  SRpcReqContext *pContext = (SRpcReqContext *)param;
  SRpcInfo *      pRpc = pContext->pRpc;
  SRpcMsg         rpcMsg;

  if (pRpc == NULL) {
    return;
  }

  tDebug("%s %p, connection error happens", pRpc->label, pContext->ahandle);

  if (pContext->numOfTry >= pContext->epSet.numOfEps || pContext->msgType == TDMT_VND_FETCH) {
    rpcMsg.msgType = pContext->msgType + 1;
    rpcMsg.ahandle = pContext->ahandle;
    rpcMsg.code = pContext->code;
    rpcMsg.pCont = NULL;
    rpcMsg.contLen = 0;

    rpcNotifyClient(pContext, &rpcMsg);
  } else {
    // move to next IP
    pContext->epSet.inUse++;
    pContext->epSet.inUse = pContext->epSet.inUse % pContext->epSet.numOfEps;
    rpcSendReqToServer(pRpc, pContext);
  }
}

static void rpcProcessRetryTimer(void *param, void *tmrId) {
  SRpcConn *pConn = (SRpcConn *)param;
  SRpcInfo *pRpc = pConn->pRpc;

  rpcLockConn(pConn);

  if (pConn->outType && pConn->user[0]) {
    tDebug("%s, expected %s is not received", pConn->info, TMSG_INFO((int)pConn->outType + 1));
    pConn->pTimer = NULL;
    pConn->retry++;

    if (pConn->retry < 4) {
      tDebug("%s, re-send msg:%s to %s:%hu", pConn->info, TMSG_INFO(pConn->outType), pConn->peerFqdn, pConn->peerPort);
      rpcSendMsgToPeer(pConn, pConn->pReqMsg, pConn->reqMsgLen);
      pConn->pTimer = taosTmrStart(rpcProcessRetryTimer, tsRpcTimer, pConn, pRpc->tmrCtrl);
    } else {
      // close the connection
      tDebug("%s, failed to send msg:%s to %s:%hu", pConn->info, TMSG_INFO(pConn->outType), pConn->peerFqdn,
             pConn->peerPort);
      if (pConn->pContext) {
        pConn->pContext->code = TSDB_CODE_RPC_NETWORK_UNAVAIL;
        pConn->pContext->pConn = NULL;
        pConn->pReqMsg = NULL;
        taosTmrStart(rpcProcessConnError, 1, pConn->pContext, pRpc->tmrCtrl);
        rpcReleaseConn(pConn);
      }
    }
  } else {
    tDebug("%s, retry timer not processed", pConn->info);
  }

  rpcUnlockConn(pConn);
}

static void rpcProcessIdleTimer(void *param, void *tmrId) {
  SRpcConn *pConn = (SRpcConn *)param;

  rpcLockConn(pConn);

  if (pConn->user[0]) {
    tDebug("%s, close the connection since no activity", pConn->info);
    if (pConn->inType) rpcReportBrokenLinkToServer(pConn);
    rpcReleaseConn(pConn);
  } else {
    tDebug("%s, idle timer:%p not processed", pConn->info, tmrId);
  }

  rpcUnlockConn(pConn);
}

static void rpcProcessProgressTimer(void *param, void *tmrId) {
  SRpcConn *pConn = (SRpcConn *)param;
  SRpcInfo *pRpc = pConn->pRpc;

  rpcLockConn(pConn);

  if (pConn->inType && pConn->user[0]) {
    tDebug("%s, progress timer expired, send progress", pConn->info);
    rpcSendQuickRsp(pConn, TSDB_CODE_RPC_ACTION_IN_PROGRESS);
    pConn->pTimer = taosTmrStart(rpcProcessProgressTimer, tsProgressTimer, pConn, pRpc->tmrCtrl);
  } else {
    tDebug("%s, progress timer:%p not processed", pConn->info, tmrId);
  }

  rpcUnlockConn(pConn);
}

static int32_t rpcCompressRpcMsg(char *pCont, int32_t contLen) {
  SRpcHead *pHead = rpcHeadFromCont(pCont);
  int32_t   finalLen = 0;
  int       overhead = sizeof(SRpcComp);

  if (!NEEDTO_COMPRESSS_MSG(contLen)) {
    return contLen;
  }

  char *buf = malloc(contLen + overhead + 8);  // 8 extra bytes
  if (buf == NULL) {
    tError("failed to allocate memory for rpc msg compression, contLen:%d", contLen);
    return contLen;
  }

  int32_t compLen = LZ4_compress_default(pCont, buf, contLen, contLen + overhead);
  tDebug("compress rpc msg, before:%d, after:%d, overhead:%d", contLen, compLen, overhead);

  /*
   * only the compressed size is less than the value of contLen - overhead, the compression is applied
   * The first four bytes is set to 0, the second four bytes are utilized to keep the original length of message
   */
  if (compLen > 0 && compLen < contLen - overhead) {
    SRpcComp *pComp = (SRpcComp *)pCont;
    pComp->reserved = 0;
    pComp->contLen = htonl(contLen);
    memcpy(pCont + overhead, buf, compLen);

    pHead->comp = 1;
    tDebug("compress rpc msg, before:%d, after:%d", contLen, compLen);
    finalLen = compLen + overhead;
  } else {
    finalLen = contLen;
  }

  free(buf);
  return finalLen;
}

static SRpcHead *rpcDecompressRpcMsg(SRpcHead *pHead) {
  int       overhead = sizeof(SRpcComp);
  SRpcHead *pNewHead = NULL;
  uint8_t * pCont = pHead->content;
  SRpcComp *pComp = (SRpcComp *)pHead->content;

  if (pHead->comp) {
    // decompress the content
    assert(pComp->reserved == 0);
    int contLen = htonl(pComp->contLen);

    // prepare the temporary buffer to decompress message
    char *temp = (char *)malloc(contLen + RPC_MSG_OVERHEAD);
    pNewHead = (SRpcHead *)(temp + sizeof(SRpcReqContext));  // reserve SRpcReqContext

    if (pNewHead) {
      int compLen = rpcContLenFromMsg(pHead->msgLen) - overhead;
      int origLen = LZ4_decompress_safe((char *)(pCont + overhead), (char *)pNewHead->content, compLen, contLen);
      assert(origLen == contLen);

      memcpy(pNewHead, pHead, sizeof(SRpcHead));
      pNewHead->msgLen = rpcMsgLenFromCont(origLen);
      rpcFreeMsg(pHead);  // free the compressed message buffer
      pHead = pNewHead;
      tTrace("decomp malloc mem:%p", temp);
    } else {
      tError("failed to allocate memory to decompress msg, contLen:%d", contLen);
    }
  }

  return pHead;
}

static int rpcAuthenticateMsg(void *pMsg, int msgLen, void *pAuth, void *pKey) {
  T_MD5_CTX context;
  int       ret = -1;

  tMD5Init(&context);
  tMD5Update(&context, (uint8_t *)pKey, TSDB_PASSWORD_LEN);
  tMD5Update(&context, (uint8_t *)pMsg, msgLen);
  tMD5Update(&context, (uint8_t *)pKey, TSDB_PASSWORD_LEN);
  tMD5Final(&context);

  if (memcmp(context.digest, pAuth, sizeof(context.digest)) == 0) ret = 0;

  return ret;
}

static void rpcBuildAuthHead(void *pMsg, int msgLen, void *pAuth, void *pKey) {
  T_MD5_CTX context;

  tMD5Init(&context);
  tMD5Update(&context, (uint8_t *)pKey, TSDB_PASSWORD_LEN);
  tMD5Update(&context, (uint8_t *)pMsg, msgLen);
  tMD5Update(&context, (uint8_t *)pKey, TSDB_PASSWORD_LEN);
  tMD5Final(&context);

  memcpy(pAuth, context.digest, sizeof(context.digest));
}

static int rpcAddAuthPart(SRpcConn *pConn, char *msg, int msgLen) {
  SRpcHead *pHead = (SRpcHead *)msg;

  if (pConn->spi && pConn->secured == 0) {
    // add auth part
    pHead->spi = pConn->spi;
    SRpcDigest *pDigest = (SRpcDigest *)(msg + msgLen);
    pDigest->timeStamp = htonl(taosGetTimestampSec());
    msgLen += sizeof(SRpcDigest);
    pHead->msgLen = (int32_t)htonl((uint32_t)msgLen);
    rpcBuildAuthHead(pHead, msgLen - TSDB_AUTH_LEN, pDigest->auth, pConn->secret);
  } else {
    pHead->spi = 0;
    pHead->msgLen = (int32_t)htonl((uint32_t)msgLen);
  }

  return msgLen;
}

static int rpcCheckAuthentication(SRpcConn *pConn, char *msg, int msgLen) {
  SRpcHead *pHead = (SRpcHead *)msg;
  int       code = 0;

  if ((pConn->secured && pHead->spi == 0) || (pHead->spi == 0 && pConn->spi == 0)) {
    // secured link, or no authentication
    pHead->msgLen = (int32_t)htonl((uint32_t)pHead->msgLen);
    // tTrace("%s, secured link, no auth is required", pConn->info);
    return 0;
  }

  if (!rpcIsReq(pHead->msgType)) {
    // for response, if code is auth failure, it shall bypass the auth process
    code = htonl(pHead->code);
    if (code == TSDB_CODE_RPC_INVALID_TIME_STAMP || code == TSDB_CODE_RPC_AUTH_FAILURE ||
        code == TSDB_CODE_RPC_INVALID_VERSION || code == TSDB_CODE_RPC_AUTH_REQUIRED ||
        code == TSDB_CODE_MND_USER_NOT_EXIST || code == TSDB_CODE_RPC_NOT_READY) {
      pHead->msgLen = (int32_t)htonl((uint32_t)pHead->msgLen);
      // tTrace("%s, dont check authentication since code is:0x%x", pConn->info, code);
      return 0;
    }
  }

  code = 0;
  if (pHead->spi == pConn->spi) {
    // authentication
    SRpcDigest *pDigest = (SRpcDigest *)((char *)pHead + msgLen - sizeof(SRpcDigest));

    int32_t delta;
    delta = (int32_t)htonl(pDigest->timeStamp);
    delta -= (int32_t)taosGetTimestampSec();
    if (abs(delta) > 900) {
      tWarn("%s, time diff:%d is too big, msg discarded", pConn->info, delta);
      code = TSDB_CODE_RPC_INVALID_TIME_STAMP;
    } else {
      if (rpcAuthenticateMsg(pHead, msgLen - TSDB_AUTH_LEN, pDigest->auth, pConn->secret) < 0) {
        tDebug("%s, authentication failed, msg discarded", pConn->info);
        code = TSDB_CODE_RPC_AUTH_FAILURE;
      } else {
        pHead->msgLen = (int32_t)htonl((uint32_t)pHead->msgLen) - sizeof(SRpcDigest);
        if (!rpcIsReq(pHead->msgType)) pConn->secured = 1;  // link is secured for client
        // tTrace("%s, message is authenticated", pConn->info);
      }
    }
  } else {
    tDebug("%s, auth spi:%d not matched with received:%d", pConn->info, pConn->spi, pHead->spi);
    code = pHead->spi ? TSDB_CODE_RPC_AUTH_FAILURE : TSDB_CODE_RPC_AUTH_REQUIRED;
  }

  return code;
}

static void rpcLockConn(SRpcConn *pConn) {
  int64_t tid = taosGetSelfPthreadId();
  int     i = 0;
  while (atomic_val_compare_exchange_64(&(pConn->lockedBy), 0, tid) != 0) {
    if (++i % 1000 == 0) {
      sched_yield();
    }
  }
}

static void rpcUnlockConn(SRpcConn *pConn) {
  int64_t tid = taosGetSelfPthreadId();
  if (atomic_val_compare_exchange_64(&(pConn->lockedBy), tid, 0) != tid) {
    assert(false);
  }
}

static void rpcAddRef(SRpcInfo *pRpc) { atomic_add_fetch_32(&pRpc->refCount, 1); }

static void rpcDecRef(SRpcInfo *pRpc) {
  if (atomic_sub_fetch_32(&pRpc->refCount, 1) == 0) {
    rpcCloseConnCache(pRpc->pCache);
    taosHashCleanup(pRpc->hash);
    taosTmrCleanUp(pRpc->tmrCtrl);
    taosIdPoolCleanUp(pRpc->idPool);

    tfree(pRpc->connList);
    pthread_mutex_destroy(&pRpc->mutex);
    tDebug("%s rpc resources are released", pRpc->label);
    tfree(pRpc);

    atomic_sub_fetch_32(&tsRpcNum, 1);
  }
}
#endif