rpcTcp.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 "rpcTcp.h"
#include "os.h"
#include "rpcHead.h"
#include "rpcLog.h"
#include "taosdef.h"
#include "taoserror.h"
#include "tutil.h"

#ifndef USE_UV
typedef struct SFdObj {
  void *             signature;
  TdSocketPtr        pSocket;       // TCP socket FD
  void *             thandle;  // handle from upper layer, like TAOS
  uint32_t           ip;
  uint16_t           port;
  int16_t            closedByApp;  // 1: already closed by App
  struct SThreadObj *pThreadObj;
  struct SFdObj *    prev;
  struct SFdObj *    next;
} SFdObj;

typedef struct SThreadObj {
  TdThread       thread;
  SFdObj *        pHead;
  TdThreadMutex mutex;
  uint32_t        ip;
  bool            stop;
  TdEpollPtr      pEpoll;
  int             numOfFds;
  int             threadId;
  char            label[TSDB_LABEL_LEN];
  void *          shandle;  // handle passed by upper layer during server initialization
  void *(*processData)(SRecvInfo *pPacket);
} SThreadObj;

typedef struct {
  char         label[TSDB_LABEL_LEN];
  int32_t      index;
  int          numOfThreads;
  SThreadObj **pThreadObj;
} SClientObj;

typedef struct {
  TdSocketServerPtr  pSocketServer;
  uint32_t           ip;
  uint16_t           port;
  int8_t             stop;
  int8_t             reserve;
  char               label[TSDB_LABEL_LEN];
  int                numOfThreads;
  void *             shandle;
  SThreadObj       **pThreadObj;
  TdThread          thread;
} SServerObj;

static void *  taosProcessTcpData(void *param);
static SFdObj *taosMallocFdObj(SThreadObj *pThreadObj, TdSocketPtr pSocket);
static void    taosFreeFdObj(SFdObj *pFdObj);
static void    taosReportBrokenLink(SFdObj *pFdObj);
static void *  taosAcceptTcpConnection(void *arg);

void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThreads, void *fp, void *shandle) {
  SServerObj *pServerObj;
  SThreadObj *pThreadObj;

  pServerObj = (SServerObj *)taosMemoryCalloc(sizeof(SServerObj), 1);
  if (pServerObj == NULL) {
    tError("TCP:%s no enough memory", label);
    terrno = TAOS_SYSTEM_ERROR(errno);
    return NULL;
  }

  pServerObj->pSocketServer = NULL;
  taosResetPthread(&pServerObj->thread);
  pServerObj->ip = ip;
  pServerObj->port = port;
  tstrncpy(pServerObj->label, label, sizeof(pServerObj->label));
  pServerObj->numOfThreads = numOfThreads;

  pServerObj->pThreadObj = (SThreadObj **)taosMemoryCalloc(sizeof(SThreadObj *), numOfThreads);
  if (pServerObj->pThreadObj == NULL) {
    tError("TCP:%s no enough memory", label);
    terrno = TAOS_SYSTEM_ERROR(errno);
    taosMemoryFree(pServerObj);
    return NULL;
  }

  int            code = 0;
  TdThreadAttr thattr;
  taosThreadAttrInit(&thattr);
  taosThreadAttrSetDetachState(&thattr, PTHREAD_CREATE_JOINABLE);

  // initialize parameters in case it may encounter error later
  for (int i = 0; i < numOfThreads; ++i) {
    pThreadObj = (SThreadObj *)taosMemoryCalloc(sizeof(SThreadObj), 1);
    if (pThreadObj == NULL) {
      tError("TCP:%s no enough memory", label);
      terrno = TAOS_SYSTEM_ERROR(errno);
      for (int j = 0; j < i; ++j) taosMemoryFree(pServerObj->pThreadObj[j]);
      taosMemoryFree(pServerObj->pThreadObj);
      taosMemoryFree(pServerObj);
      return NULL;
    }

    pServerObj->pThreadObj[i] = pThreadObj;
    pThreadObj->pEpoll = NULL;
    taosResetPthread(&pThreadObj->thread);
    pThreadObj->processData = fp;
    tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
    pThreadObj->shandle = shandle;
    pThreadObj->stop = false;
  }

  // initialize mutex, thread, fd which may fail
  for (int i = 0; i < numOfThreads; ++i) {
    pThreadObj = pServerObj->pThreadObj[i];
    code = taosThreadMutexInit(&(pThreadObj->mutex), NULL);
    if (code < 0) {
      tError("%s failed to init TCP process data mutex(%s)", label, strerror(errno));
      break;
    }

    pThreadObj->pEpoll = taosCreateEpoll(10);  // size does not matter
    if (pThreadObj->pEpoll == NULL) {
      tError("%s failed to create TCP epoll", label);
      code = -1;
      break;
    }

    code = taosThreadCreate(&(pThreadObj->thread), &thattr, taosProcessTcpData, (void *)(pThreadObj));
    if (code != 0) {
      tError("%s failed to create TCP process data thread(%s)", label, strerror(errno));
      break;
    }

    pThreadObj->threadId = i;
  }

  pServerObj->pSocketServer = taosOpenTcpServerSocket(pServerObj->ip, pServerObj->port);
  if (pServerObj->pSocketServer == NULL) code = -1;

  if (code == 0) {
    code = taosThreadCreate(&pServerObj->thread, &thattr, taosAcceptTcpConnection, (void *)pServerObj);
    if (code != 0) {
      tError("%s failed to create TCP accept thread(%s)", label, strerror(code));
    }
  }

  if (code != 0) {
    terrno = TAOS_SYSTEM_ERROR(errno);
    taosCleanUpTcpServer(pServerObj);
    pServerObj = NULL;
  } else {
    tDebug("%s TCP server is initialized, ip:0x%x port:%hu numOfThreads:%d", label, ip, port, numOfThreads);
  }

  taosThreadAttrDestroy(&thattr);
  return (void *)pServerObj;
}

static void taosStopTcpThread(SThreadObj *pThreadObj) {
  if (pThreadObj == NULL) {
    return;
  }
  // save thread into local variable and signal thread to stop
  TdThread thread = pThreadObj->thread;
  if (!taosCheckPthreadValid(thread)) {
    return;
  }
  pThreadObj->stop = true;
  if (taosComparePthread(thread, taosThreadSelf())) {
    pthread_detach(taosThreadSelf());
    return;
  }
  taosThreadJoin(thread, NULL);
}

void taosStopTcpServer(void *handle) {
  SServerObj *pServerObj = handle;

  if (pServerObj == NULL) return;
  pServerObj->stop = 1;

  if (pServerObj->pSocketServer != NULL) {
    taosShutDownSocketServerRD(pServerObj->pSocketServer);
  }
  if (taosCheckPthreadValid(pServerObj->thread)) {
    if (taosComparePthread(pServerObj->thread, taosThreadSelf())) {
      pthread_detach(taosThreadSelf());
    } else {
      taosThreadJoin(pServerObj->thread, NULL);
    }
  }

  tDebug("%s TCP server is stopped", pServerObj->label);
}

void taosCleanUpTcpServer(void *handle) {
  SServerObj *pServerObj = handle;
  SThreadObj *pThreadObj;
  if (pServerObj == NULL) return;

  for (int i = 0; i < pServerObj->numOfThreads; ++i) {
    pThreadObj = pServerObj->pThreadObj[i];
    taosStopTcpThread(pThreadObj);
  }

  tDebug("%s TCP server is cleaned up", pServerObj->label);

  taosMemoryFreeClear(pServerObj->pThreadObj);
  taosMemoryFreeClear(pServerObj);
}

static void *taosAcceptTcpConnection(void *arg) {
  TdSocketPtr        pSocket = NULL;
  struct sockaddr_in caddr;
  int                threadId = 0;
  SThreadObj *       pThreadObj;
  SServerObj *       pServerObj;

  pServerObj = (SServerObj *)arg;
  tDebug("%s TCP server is ready, ip:0x%x:%hu", pServerObj->label, pServerObj->ip, pServerObj->port);
  setThreadName("acceptTcpConn");

  while (1) {
    socklen_t addrlen = sizeof(caddr);
    pSocket = taosAcceptTcpConnectSocket(pServerObj->pSocketServer, (struct sockaddr *)&caddr, &addrlen);
    if (pServerObj->stop) {
      tDebug("%s TCP server stop accepting new connections", pServerObj->label);
      break;
    }

    if (pSocket == NULL) {
      if (errno == EINVAL) {
        tDebug("%s TCP server stop accepting new connections, exiting", pServerObj->label);
        break;
      }

      tError("%s TCP accept failure(%s)", pServerObj->label, strerror(errno));
      continue;
    }

    taosKeepTcpAlive(pSocket);
    struct timeval to = {5, 0};
    int32_t        ret = taosSetSockOpt(pSocket, SOL_SOCKET, SO_RCVTIMEO, &to, sizeof(to));
    if (ret != 0) {
      taosCloseSocket(&pSocket);
      tError("%s failed to set recv timeout fd(%s)for connection from:%s:%hu", pServerObj->label, strerror(errno),
             taosInetNtoa(caddr.sin_addr), htons(caddr.sin_port));
      continue;
    }

    // pick up the thread to handle this connection
    pThreadObj = pServerObj->pThreadObj[threadId];

    SFdObj *pFdObj = taosMallocFdObj(pThreadObj, pSocket);
    if (pFdObj) {
      pFdObj->ip = caddr.sin_addr.s_addr;
      pFdObj->port = htons(caddr.sin_port);
      tDebug("%s new TCP connection from %s:%hu, FD:%p numOfFds:%d", pServerObj->label,
             taosInetNtoa(caddr.sin_addr), pFdObj->port, pFdObj, pThreadObj->numOfFds);
    } else {
      taosCloseSocket(&pSocket);
      tError("%s failed to malloc FdObj(%s) for connection from:%s:%hu", pServerObj->label, strerror(errno),
             taosInetNtoa(caddr.sin_addr), htons(caddr.sin_port));
    }

    // pick up next thread for next connection
    threadId++;
    threadId = threadId % pServerObj->numOfThreads;
  }

  taosCloseSocketServer(&pServerObj->pSocketServer);
  return NULL;
}

void *taosInitTcpClient(uint32_t ip, uint16_t port, char *label, int numOfThreads, void *fp, void *shandle) {
  SClientObj *pClientObj = (SClientObj *)taosMemoryCalloc(1, sizeof(SClientObj));
  if (pClientObj == NULL) {
    tError("TCP:%s no enough memory", label);
    terrno = TAOS_SYSTEM_ERROR(errno);
    return NULL;
  }

  tstrncpy(pClientObj->label, label, sizeof(pClientObj->label));
  pClientObj->numOfThreads = numOfThreads;
  pClientObj->pThreadObj = (SThreadObj **)taosMemoryCalloc(numOfThreads, sizeof(SThreadObj *));
  if (pClientObj->pThreadObj == NULL) {
    tError("TCP:%s no enough memory", label);
    taosMemoryFreeClear(pClientObj);
    terrno = TAOS_SYSTEM_ERROR(errno);
  }

  int            code = 0;
  TdThreadAttr thattr;
  taosThreadAttrInit(&thattr);
  taosThreadAttrSetDetachState(&thattr, PTHREAD_CREATE_JOINABLE);

  for (int i = 0; i < numOfThreads; ++i) {
    SThreadObj *pThreadObj = (SThreadObj *)taosMemoryCalloc(1, sizeof(SThreadObj));
    if (pThreadObj == NULL) {
      tError("TCP:%s no enough memory", label);
      terrno = TAOS_SYSTEM_ERROR(errno);
      for (int j = 0; j < i; ++j) taosMemoryFree(pClientObj->pThreadObj[j]);
      taosMemoryFree(pClientObj);
      taosThreadAttrDestroy(&thattr);
      return NULL;
    }
    pClientObj->pThreadObj[i] = pThreadObj;
    taosResetPthread(&pThreadObj->thread);
    pThreadObj->ip = ip;
    pThreadObj->stop = false;
    tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
    pThreadObj->shandle = shandle;
    pThreadObj->processData = fp;
  }

  // initialize mutex, thread, fd which may fail
  for (int i = 0; i < numOfThreads; ++i) {
    SThreadObj *pThreadObj = pClientObj->pThreadObj[i];
    code = taosThreadMutexInit(&(pThreadObj->mutex), NULL);
    if (code < 0) {
      tError("%s failed to init TCP process data mutex(%s)", label, strerror(errno));
      break;
    }

    pThreadObj->pEpoll = taosCreateEpoll(10);  // size does not matter
    if (pThreadObj->pEpoll == NULL) {
      tError("%s failed to create TCP epoll", label);
      code = -1;
      break;
    }

    code = taosThreadCreate(&(pThreadObj->thread), &thattr, taosProcessTcpData, (void *)(pThreadObj));
    if (code != 0) {
      tError("%s failed to create TCP process data thread(%s)", label, strerror(errno));
      break;
    }
    pThreadObj->threadId = i;
  }
  if (code != 0) {
    terrno = TAOS_SYSTEM_ERROR(errno);
    taosCleanUpTcpClient(pClientObj);
    pClientObj = NULL;
  }
  return pClientObj;
}

void taosStopTcpClient(void *chandle) {
  SClientObj *pClientObj = chandle;

  if (pClientObj == NULL) return;

  tDebug("%s TCP client is stopped", pClientObj->label);
}

void taosCleanUpTcpClient(void *chandle) {
  SClientObj *pClientObj = chandle;
  if (pClientObj == NULL) return;
  for (int i = 0; i < pClientObj->numOfThreads; ++i) {
    SThreadObj *pThreadObj = pClientObj->pThreadObj[i];
    taosStopTcpThread(pThreadObj);
  }

  tDebug("%s TCP client is cleaned up", pClientObj->label);
  taosMemoryFreeClear(pClientObj->pThreadObj);
  taosMemoryFreeClear(pClientObj);
}

void *taosOpenTcpClientConnection(void *shandle, void *thandle, uint32_t ip, uint16_t port) {
  SClientObj *pClientObj = shandle;
  int32_t     index = atomic_load_32(&pClientObj->index) % pClientObj->numOfThreads;
  atomic_store_32(&pClientObj->index, index + 1);
  SThreadObj *pThreadObj = pClientObj->pThreadObj[index];

  TdSocketPtr pSocket = taosOpenTcpClientSocket(ip, port, pThreadObj->ip);
  if (pSocket == NULL) return NULL;

  struct sockaddr_in sin;
  uint16_t           localPort = 0;
  unsigned int       addrlen = sizeof(sin);
  if (taosGetSocketName(pSocket, (struct sockaddr *)&sin, &addrlen) == 0 && sin.sin_family == AF_INET && addrlen == sizeof(sin)) {
    localPort = (uint16_t)ntohs(sin.sin_port);
  }

  SFdObj *pFdObj = taosMallocFdObj(pThreadObj, pSocket);

  if (pFdObj) {
    pFdObj->thandle = thandle;
    pFdObj->port = port;
    pFdObj->ip = ip;

    char ipport[40] = {0};
    taosIpPort2String(ip, port, ipport);
    tDebug("%s %p TCP connection to %s is created, localPort:%hu FD:%p numOfFds:%d", pThreadObj->label, thandle,
           ipport, localPort, pFdObj, pThreadObj->numOfFds);
  } else {
    tError("%s failed to malloc client FdObj(%s)", pThreadObj->label, strerror(errno));
    taosCloseSocket(&pSocket);
  }

  return pFdObj;
}

void taosCloseTcpConnection(void *chandle) {
  SFdObj *pFdObj = chandle;
  if (pFdObj == NULL || pFdObj->signature != pFdObj) return;

  SThreadObj *pThreadObj = pFdObj->pThreadObj;
  tDebug("%s %p TCP connection will be closed, FD:%p", pThreadObj->label, pFdObj->thandle, pFdObj);

  // pFdObj->thandle = NULL;
  pFdObj->closedByApp = 1;
  taosShutDownSocketWR(pFdObj->pSocket);
}

int taosSendTcpData(uint32_t ip, uint16_t port, void *data, int len, void *chandle) {
  SFdObj *pFdObj = chandle;
  if (pFdObj == NULL || pFdObj->signature != pFdObj) return -1;
  SThreadObj *pThreadObj = pFdObj->pThreadObj;

  int ret = taosWriteMsg(pFdObj->pSocket, data, len);
  tTrace("%s %p TCP data is sent, FD:%p bytes:%d", pThreadObj->label, pFdObj->thandle, pFdObj, ret);

  return ret;
}

static void taosReportBrokenLink(SFdObj *pFdObj) {
  SThreadObj *pThreadObj = pFdObj->pThreadObj;

  // notify the upper layer, so it will clean the associated context
  if (pFdObj->closedByApp == 0) {
    taosShutDownSocketWR(pFdObj->pSocket);

    SRecvInfo recvInfo;
    recvInfo.msg = NULL;
    recvInfo.msgLen = 0;
    recvInfo.ip = 0;
    recvInfo.port = 0;
    recvInfo.shandle = pThreadObj->shandle;
    recvInfo.thandle = pFdObj->thandle;
    recvInfo.chandle = NULL;
    recvInfo.connType = RPC_CONN_TCP;
    (*(pThreadObj->processData))(&recvInfo);
  }

  taosFreeFdObj(pFdObj);
}

static int taosReadTcpData(SFdObj *pFdObj, SRecvInfo *pInfo) {
  SRpcHead rpcHead;
  int32_t  msgLen, leftLen, retLen, headLen;
  char *   buffer, *msg;

  SThreadObj *pThreadObj = pFdObj->pThreadObj;

  headLen = taosReadMsg(pFdObj->pSocket, &rpcHead, sizeof(SRpcHead));
  if (headLen != sizeof(SRpcHead)) {
    tDebug("%s %p read error, FD:%p headLen:%d", pThreadObj->label, pFdObj->thandle, pFdObj, headLen);
    return -1;
  }

  msgLen = (int32_t)htonl((uint32_t)rpcHead.msgLen);
  int32_t size = msgLen + tsRpcOverhead;
  buffer = taosMemoryMalloc(size);
  if (NULL == buffer) {
    tError("%s %p TCP taosMemoryMalloc(size:%d) fail", pThreadObj->label, pFdObj->thandle, msgLen);
    return -1;
  } else {
    tTrace("%s %p read data, FD:%p TCP malloc mem:%p", pThreadObj->label, pFdObj->thandle, pFdObj, buffer);
  }

  msg = buffer + tsRpcOverhead;
  leftLen = msgLen - headLen;
  retLen = taosReadMsg(pFdObj->pSocket, msg + headLen, leftLen);

  if (leftLen != retLen) {
    tError("%s %p read error, leftLen:%d retLen:%d FD:%p", pThreadObj->label, pFdObj->thandle, leftLen, retLen, pFdObj);
    taosMemoryFree(buffer);
    return -1;
  }

  memcpy(msg, &rpcHead, sizeof(SRpcHead));

  pInfo->msg = msg;
  pInfo->msgLen = msgLen;
  pInfo->ip = pFdObj->ip;
  pInfo->port = pFdObj->port;
  pInfo->shandle = pThreadObj->shandle;
  pInfo->thandle = pFdObj->thandle;
  pInfo->chandle = pFdObj;
  pInfo->connType = RPC_CONN_TCP;

  if (pFdObj->closedByApp) {
    taosMemoryFree(buffer);
    return -1;
  }

  return 0;
}

#define maxEvents 10

static void *taosProcessTcpData(void *param) {
  SThreadObj *       pThreadObj = param;
  SFdObj *           pFdObj;
  struct epoll_event events[maxEvents];
  SRecvInfo          recvInfo;

  char name[16] = {0};
  snprintf(name, tListLen(name), "%s-tcp", pThreadObj->label);
  setThreadName(name);

  while (1) {
    int fdNum = taosWaitEpoll(pThreadObj->pEpoll, events, maxEvents, TAOS_EPOLL_WAIT_TIME);
    if (pThreadObj->stop) {
      tDebug("%s TCP thread get stop event, exiting...", pThreadObj->label);
      break;
    }
    if (fdNum < 0) continue;

    for (int i = 0; i < fdNum; ++i) {
      pFdObj = events[i].data.ptr;

      if (events[i].events & EPOLLERR) {
        tDebug("%s %p FD:%p epoll errors", pThreadObj->label, pFdObj->thandle, pFdObj);
        taosReportBrokenLink(pFdObj);
        continue;
      }

      if (events[i].events & EPOLLRDHUP) {
        tDebug("%s %p FD:%p RD hang up", pThreadObj->label, pFdObj->thandle, pFdObj);
        taosReportBrokenLink(pFdObj);
        continue;
      }

      if (events[i].events & EPOLLHUP) {
        tDebug("%s %p FD:%p hang up", pThreadObj->label, pFdObj->thandle, pFdObj);
        taosReportBrokenLink(pFdObj);
        continue;
      }

      if (taosReadTcpData(pFdObj, &recvInfo) < 0) {
        taosShutDownSocketWR(pFdObj->pSocket);
        continue;
      }

      pFdObj->thandle = (*(pThreadObj->processData))(&recvInfo);
      if (pFdObj->thandle == NULL) taosFreeFdObj(pFdObj);
    }

    if (pThreadObj->stop) break;
  }

  if (pThreadObj->pEpoll != NULL) {
    taosCloseEpoll(&pThreadObj->pEpoll);
    pThreadObj->pEpoll = NULL;
  }

  while (pThreadObj->pHead) {
    pFdObj = pThreadObj->pHead;
    pThreadObj->pHead = pFdObj->next;
    taosReportBrokenLink(pFdObj);
  }

  taosThreadMutexDestroy(&(pThreadObj->mutex));
  tDebug("%s TCP thread exits ...", pThreadObj->label);
  taosMemoryFreeClear(pThreadObj);

  return NULL;
}

static SFdObj *taosMallocFdObj(SThreadObj *pThreadObj, TdSocketPtr pSocket) {
  struct epoll_event event;

  SFdObj *pFdObj = (SFdObj *)taosMemoryCalloc(sizeof(SFdObj), 1);
  if (pFdObj == NULL) {
    return NULL;
  }

  pFdObj->closedByApp = 0;
  pFdObj->pSocket = pSocket;
  pFdObj->pThreadObj = pThreadObj;
  pFdObj->signature = pFdObj;

  event.events = EPOLLIN | EPOLLRDHUP;
  event.data.ptr = pFdObj;
  if (taosCtlEpoll(pThreadObj->pEpoll, EPOLL_CTL_ADD, pSocket, &event) < 0) {
    taosMemoryFreeClear(pFdObj);
    terrno = TAOS_SYSTEM_ERROR(errno);
    return NULL;
  }

  // notify the data process, add into the FdObj list
  taosThreadMutexLock(&(pThreadObj->mutex));
  pFdObj->next = pThreadObj->pHead;
  if (pThreadObj->pHead) (pThreadObj->pHead)->prev = pFdObj;
  pThreadObj->pHead = pFdObj;
  pThreadObj->numOfFds++;
  taosThreadMutexUnlock(&(pThreadObj->mutex));

  return pFdObj;
}

static void taosFreeFdObj(SFdObj *pFdObj) {
  if (pFdObj == NULL) return;
  if (pFdObj->signature != pFdObj) return;

  SThreadObj *pThreadObj = pFdObj->pThreadObj;
  taosThreadMutexLock(&pThreadObj->mutex);

  if (pFdObj->signature == NULL) {
    taosThreadMutexUnlock(&pThreadObj->mutex);
    return;
  }

  pFdObj->signature = NULL;
  taosCtlEpoll(pThreadObj->pEpoll, EPOLL_CTL_DEL, pFdObj->pSocket, NULL);
  taosCloseSocket(&pFdObj->pSocket);

  pThreadObj->numOfFds--;
  if (pThreadObj->numOfFds < 0)
    tError("%s %p TCP thread:%d, number of FDs is negative!!!", pThreadObj->label, pFdObj->thandle,
           pThreadObj->threadId);

  if (pFdObj->prev) {
    (pFdObj->prev)->next = pFdObj->next;
  } else {
    pThreadObj->pHead = pFdObj->next;
  }

  if (pFdObj->next) {
    (pFdObj->next)->prev = pFdObj->prev;
  }

  taosThreadMutexUnlock(&pThreadObj->mutex);

  tDebug("%s %p TCP connection is closed, FD:%p numOfFds:%d", pThreadObj->label, pFdObj->thandle, pFdObj, pThreadObj->numOfFds);

  taosMemoryFreeClear(pFdObj);
}
#endif