Update snapshot(2017-11-23)
[platform/upstream/iotivity.git] / resource / csdk / connectivity / src / tcp_adapter / catcpserver.c
index d87beef..78b43bb 100644 (file)
 #include <sys/socket.h>
 #include <sys/select.h>
 #include <sys/ioctl.h>
+#ifdef __TIZENRT__
+#include <tinyara/config.h>
+#include <poll.h>
+#else
 #include <sys/poll.h>
+#endif
 #include <stdio.h>
 #include <unistd.h>
 #include <fcntl.h>
 #endif
 
 #include "catcpinterface.h"
-#include "pdu.h"
+#include "caipnwmonitor.h"
+#include <coap/pdu.h>
 #include "caadapterutils.h"
-#include "camutex.h"
+#include "octhread.h"
 #include "oic_malloc.h"
 
 #ifdef __WITH_TLS__
-#include "ca_adapter_net_tls.h"
+#include "ca_adapter_net_ssl.h"
 #endif
 
 /**
  * Logging tag for module name.
  */
-#define TAG "OIC_CA_TCP_SERVER"
+//#define TAG "OIC_CA_TCP_SERVER"
+#define TAG TCP_SERVER_TAG
 
 /**
  * Maximum CoAP over TCP header length
 #define TLS_HEADER_SIZE 5
 
 /**
+ * Max Connection Counts.
+ */
+#define MAX_CONNECTION_COUNTS   500
+
+/**
+ * Thread pool.
+ */
+static ca_thread_pool_t g_threadPool = NULL;
+
+/**
+ * An unique identifier of receive thread.
+ */
+static uint32_t g_recvThreadId = 0;
+
+/**
  * Mutex to synchronize device object list.
  */
-static ca_mutex g_mutexObjectList = NULL;
+static oc_mutex g_mutexObjectList = NULL;
 
 /**
  * Conditional mutex to synchronize.
  */
-static ca_cond g_condObjectList = NULL;
+static oc_cond g_condObjectList = NULL;
 
 /**
  * Maintains the callback to be notified when data received from remote device.
@@ -88,86 +110,46 @@ static CATCPErrorHandleCallback g_tcpErrorHandler = NULL;
  */
 static CATCPConnectionHandleCallback g_connectionCallback = NULL;
 
-static CAResult_t CATCPCreateMutex();
-static void CATCPDestroyMutex();
-static CAResult_t CATCPCreateCond();
-static void CATCPDestroyCond();
-static int CACreateAcceptSocket(int family, CASocket_t *sock);
+static CASocketFd_t CACreateAcceptSocket(int family, CASocket_t *sock);
 static void CAAcceptConnection(CATransportFlags_t flag, CASocket_t *sock);
 static void CAFindReadyMessage();
 static void CASelectReturned(fd_set *readFds);
 static void CAReceiveMessage(int fd);
 static void CAReceiveHandler(void *data);
-static int CATCPCreateSocket(int family, CATCPSessionInfo_t *tcpServerInfo);
+static CAResult_t CATCPCreateSocket(int family, CATCPSessionInfo_t *svritem);
+static void CATCPInitializeSocket();
 
 #define CHECKFD(FD) \
     if (FD > caglobals.tcp.maxfd) \
         caglobals.tcp.maxfd = FD;
 
-#define REALLOC(buffer, length) \
-{ \
-    unsigned char *tmpBuf = OICRealloc(buffer, length); \
-    if (!tmpBuf) \
+#define CLOSE_SOCKET(TYPE) \
+    if (caglobals.tcp.TYPE.fd != OC_INVALID_SOCKET) \
     { \
-        OIC_LOG(ERROR, TAG, "out of memory"); \
-        goto error; \
-    } \
-    buffer = tmpBuf; \
-}
+        close(caglobals.tcp.TYPE.fd); \
+        caglobals.tcp.TYPE.fd = OC_INVALID_SOCKET; \
+    }
 
-/**
- * Read length amount of data from socket fd
- * Made a few recv calls if required
- *
- * @param[in]  fd     - socket
- * @param[out] item   - used to update received message length
- * @param[out] data   - buffer to store data
- * @param[in]  length - length of data required to read
- * @param[in]  flags  - additional info about socket
- */
-#define RECV(fd, item, data, length, flags) \
-{ \
-    int remain_len = length; \
-    int len = 0; \
-    while (remain_len > 0) \
+#define CA_FD_SET(TYPE, FDS) \
+    if (caglobals.tcp.TYPE.fd != OC_INVALID_SOCKET) \
     { \
-        len = recv(fd, data + item->len, remain_len, flags); \
-        OIC_LOG_V(DEBUG, TAG, "recv len = %d", len); \
-        OIC_LOG_BUFFER(DEBUG, TAG, data + item->len, len); \
-        if (2 == len && 0 == data[item->len] && 0 == data[item->len + 1]) \
-        { \
-            OIC_LOG(DEBUG, TAG, "received RESET message. Skip it"); \
-            continue; \
-        } \
-        if (len < 0) \
-        { \
-            OIC_LOG_V(ERROR, TAG, "recv failed %s", strerror(errno)); \
-            goto error; \
-        } \
-        else if (0 == len) \
-        { \
-            OIC_LOG(INFO, TAG, "Received disconnect from peer. Close connection"); \
-            goto error; \
-        } \
-        item->len += len; \
-        remain_len -= len; \
-    } \
-}
+        FD_SET(caglobals.tcp.TYPE.fd, FDS); \
+    }
 
-static void CATCPDestroyMutex()
+void CATCPDestroyMutex()
 {
     if (g_mutexObjectList)
     {
-        ca_mutex_free(g_mutexObjectList);
+        oc_mutex_free(g_mutexObjectList);
         g_mutexObjectList = NULL;
     }
 }
 
-static CAResult_t CATCPCreateMutex()
+CAResult_t CATCPCreateMutex()
 {
     if (!g_mutexObjectList)
     {
-        g_mutexObjectList = ca_mutex_new();
+        g_mutexObjectList = oc_mutex_new();
         if (!g_mutexObjectList)
         {
             OIC_LOG(ERROR, TAG, "Failed to created mutex!");
@@ -178,20 +160,20 @@ static CAResult_t CATCPCreateMutex()
     return CA_STATUS_OK;
 }
 
-static void CATCPDestroyCond()
+void CATCPDestroyCond()
 {
     if (g_condObjectList)
     {
-        ca_cond_free(g_condObjectList);
+        oc_cond_free(g_condObjectList);
         g_condObjectList = NULL;
     }
 }
 
-static CAResult_t CATCPCreateCond()
+CAResult_t CATCPCreateCond()
 {
     if (!g_condObjectList)
     {
-        g_condObjectList = ca_cond_new();
+        g_condObjectList = oc_cond_new();
         if (!g_condObjectList)
         {
             OIC_LOG(ERROR, TAG, "Failed to created cond!");
@@ -211,9 +193,9 @@ static void CAReceiveHandler(void *data)
         CAFindReadyMessage();
     }
 
-    ca_mutex_lock(g_mutexObjectList);
-    ca_cond_signal(g_condObjectList);
-    ca_mutex_unlock(g_mutexObjectList);
+    oc_mutex_lock(g_mutexObjectList);
+    oc_cond_signal(g_condObjectList);
+    oc_mutex_unlock(g_mutexObjectList);
 
     OIC_LOG(DEBUG, TAG, "OUT - CAReceiveHandler");
 }
@@ -224,20 +206,17 @@ static void CAFindReadyMessage()
     struct timeval timeout = { .tv_sec = caglobals.tcp.selectTimeout };
 
     FD_ZERO(&readFds);
-
-    if (-1 != caglobals.tcp.ipv4.fd)
-    {
-        FD_SET(caglobals.tcp.ipv4.fd, &readFds);
-    }
-    if (-1 != caglobals.tcp.ipv6.fd)
-    {
-        FD_SET(caglobals.tcp.ipv6.fd, &readFds);
-    }
-    if (-1 != caglobals.tcp.shutdownFds[0])
+    CA_FD_SET(ipv4, &readFds);
+    CA_FD_SET(ipv4s, &readFds);
+    CA_FD_SET(ipv6, &readFds);
+    CA_FD_SET(ipv6s, &readFds);
+#ifndef __TIZENRT__
+    if (OC_INVALID_SOCKET != caglobals.tcp.shutdownFds[0])
     {
         FD_SET(caglobals.tcp.shutdownFds[0], &readFds);
     }
-    if (-1 != caglobals.tcp.connectionFds[0])
+#endif
+    if (OC_INVALID_SOCKET != caglobals.tcp.connectionFds[0])
     {
         FD_SET(caglobals.tcp.connectionFds[0], &readFds);
     }
@@ -247,7 +226,7 @@ static void CAFindReadyMessage()
     {
         CATCPSessionInfo_t *svritem =
                 (CATCPSessionInfo_t *) u_arraylist_get(caglobals.tcp.svrlist, i);
-        if (svritem && 0 <= svritem->fd)
+        if (svritem && 0 <= svritem->fd && CONNECTED == svritem->state)
         {
             FD_SET(svritem->fd, &readFds);
         }
@@ -257,7 +236,7 @@ static void CAFindReadyMessage()
 
     if (caglobals.tcp.terminate)
     {
-        OIC_LOG_V(DEBUG, TAG, "Packet receiver Stop request received.");
+        OIC_LOG_V(INFO, TAG, "Packet receiver Stop request received.");
         return;
     }
     if (0 >= ret)
@@ -281,11 +260,21 @@ static void CASelectReturned(fd_set *readFds)
         CAAcceptConnection(CA_IPV4, &caglobals.tcp.ipv4);
         return;
     }
+    else if (caglobals.tcp.ipv4s.fd != -1 && FD_ISSET(caglobals.tcp.ipv4s.fd, readFds))
+    {
+        CAAcceptConnection(CA_IPV4 | CA_SECURE, &caglobals.tcp.ipv4s);
+        return;
+    }
     else if (caglobals.tcp.ipv6.fd != -1 && FD_ISSET(caglobals.tcp.ipv6.fd, readFds))
     {
         CAAcceptConnection(CA_IPV6, &caglobals.tcp.ipv6);
         return;
     }
+    else if (caglobals.tcp.ipv6s.fd != -1 && FD_ISSET(caglobals.tcp.ipv6s.fd, readFds))
+    {
+        CAAcceptConnection(CA_IPV6 | CA_SECURE, &caglobals.tcp.ipv6s);
+        return;
+    }
     else if (-1 != caglobals.tcp.connectionFds[0] &&
             FD_ISSET(caglobals.tcp.connectionFds[0], readFds))
     {
@@ -298,7 +287,6 @@ static void CASelectReturned(fd_set *readFds)
             return;
         }
         OIC_LOG_V(DEBUG, TAG, "Received new connection event with [%s]", buf);
-        FD_CLR(caglobals.tcp.connectionFds[0], readFds);
         return;
     }
     else
@@ -313,7 +301,6 @@ static void CASelectReturned(fd_set *readFds)
                 if (FD_ISSET(svritem->fd, readFds))
                 {
                     CAReceiveMessage(svritem->fd);
-                    FD_CLR(svritem->fd, readFds);
                 }
             }
         }
@@ -322,8 +309,17 @@ static void CASelectReturned(fd_set *readFds)
 
 static void CAAcceptConnection(CATransportFlags_t flag, CASocket_t *sock)
 {
+    OIC_LOG_V(INFO, TAG, "In %s", __func__);
     VERIFY_NON_NULL_VOID(sock, TAG, "sock is NULL");
 
+    if (MAX_CONNECTION_COUNTS == u_arraylist_length(caglobals.tcp.svrlist))
+    {
+        OIC_LOG_V(INFO, TAG, "Exceeding the max connection counts limit, close listening port");
+        close(sock->fd);
+        sock->fd = OC_INVALID_SOCKET;
+        return;
+    }
+
     struct sockaddr_storage clientaddr;
     socklen_t clientlen = sizeof (struct sockaddr_in);
     if (flag & CA_IPV6)
@@ -331,8 +327,8 @@ static void CAAcceptConnection(CATransportFlags_t flag, CASocket_t *sock)
         clientlen = sizeof(struct sockaddr_in6);
     }
 
-    int sockfd = accept(sock->fd, (struct sockaddr *)&clientaddr, &clientlen);
-    if (-1 != sockfd)
+    CASocketFd_t sockfd = accept(sock->fd, (struct sockaddr *)&clientaddr, &clientlen);
+    if (OC_INVALID_SOCKET != sockfd)
     {
         CATCPSessionInfo_t *svritem =
                 (CATCPSessionInfo_t *) OICCalloc(1, sizeof (*svritem));
@@ -345,56 +341,176 @@ static void CAAcceptConnection(CATransportFlags_t flag, CASocket_t *sock)
 
         svritem->fd = sockfd;
         svritem->sep.endpoint.flags = flag;
+        svritem->sep.endpoint.adapter = CA_ADAPTER_TCP;
+        svritem->state = CONNECTED;
+        svritem->isClient = false;
         CAConvertAddrToName((struct sockaddr_storage *)&clientaddr, clientlen,
                             svritem->sep.endpoint.addr, &svritem->sep.endpoint.port);
 
-        ca_mutex_lock(g_mutexObjectList);
+        oc_mutex_lock(g_mutexObjectList);
         bool result = u_arraylist_add(caglobals.tcp.svrlist, svritem);
         if (!result)
         {
             OIC_LOG(ERROR, TAG, "u_arraylist_add failed.");
             close(sockfd);
             OICFree(svritem);
-            ca_mutex_unlock(g_mutexObjectList);
+            oc_mutex_unlock(g_mutexObjectList);
             return;
         }
-        ca_mutex_unlock(g_mutexObjectList);
+        oc_mutex_unlock(g_mutexObjectList);
 
         CHECKFD(sockfd);
+
+        // pass the connection information to CA Common Layer.
+        if (g_connectionCallback)
+        {
+            g_connectionCallback(&(svritem->sep.endpoint), true, svritem->isClient);
+        }
     }
+    OIC_LOG_V(INFO, TAG, "Out %s", __func__);
 }
 
+/**
+ * Clean socket state data
+ *
+ * @param[in/out] item - socket state data
+ */
+void CACleanData(CATCPSessionInfo_t *svritem)
+{
+    if (svritem)
+    {
+        OICFree(svritem->data);
+        svritem->data = NULL;
+        svritem->len = 0;
 #ifdef __WITH_TLS__
-static bool CAIsTlsMessage(const CATCPSessionInfo_t * recvinfo)
+        svritem->tlsLen = 0;
+#endif
+        svritem->totalLen = 0;
+        svritem->protocol = UNKNOWN;
+    }
+}
+
+/**
+ * Construct CoAP header and payload from buffer
+ *
+ * @param[in] svritem - used socket, buffer, current received message length and protocol
+ * @param[in/out]  data  - data buffer, this value is updated as data is copied to svritem
+ * @param[in/out]  dataLength  - length of data, this value decreased as data is copied to svritem
+ * @return             - CA_STATUS_OK or appropriate error code
+ */
+CAResult_t CAConstructCoAP(CATCPSessionInfo_t *svritem, unsigned char **data,
+                          size_t *dataLength)
 {
-    if (recvinfo->data == NULL || recvinfo->len == 0)
+    OIC_LOG_V(DEBUG, TAG, "In %s", __func__);
+
+    if (NULL == svritem || NULL == data || NULL == dataLength)
     {
-        OIC_LOG_V(ERROR, TAG, "%s: null input param", __func__);
-        return false;
+        OIC_LOG(ERROR, TAG, "Invalid input parameter(NULL)");
+        return CA_STATUS_INVALID_PARAM;
     }
 
-    unsigned char first_byte = recvinfo->data[0];
+    unsigned char *inBuffer = *data;
+    size_t inLen = *dataLength;
+    OIC_LOG_V(DEBUG, TAG, "before-datalength : %u", *dataLength);
+
+    if (NULL == svritem->data && inLen > 0)
+    {
+        // allocate memory for message header (CoAP header size because it is bigger)
+        svritem->data = (unsigned char *) OICCalloc(1, COAP_MAX_HEADER_SIZE);
+        if (NULL == svritem->data)
+        {
+            OIC_LOG(ERROR, TAG, "OICCalloc - out of memory");
+            return CA_MEMORY_ALLOC_FAILED;
+        }
 
-    //TLS Plaintext has four types: change_cipher_spec = [14], alert = [15],
-    //handshake = [16], application_data = [17] in HEX
-    const uint8_t tls_head_type[] = {0x14, 0x15, 0x16, 0x17};
-    size_t i = 0;
+        // copy 1 byte to parse coap header length
+        memcpy(svritem->data, inBuffer, 1);
+        svritem->len = 1;
+        inBuffer++;
+        inLen--;
+    }
 
-    for (i = 0; i < sizeof(tls_head_type); i++)
+    //if not enough data received - read them on next CAFillHeader() call
+    if (0 == inLen)
     {
-        if(tls_head_type[i] == first_byte)
+        return CA_STATUS_OK;
+    }
+
+    //if enough data received - parse header
+    svritem->protocol = COAP;
+
+    //seems CoAP data received. read full coap header.
+    coap_transport_t transport = coap_get_tcp_header_type_from_initbyte(svritem->data[0] >> 4);
+    size_t headerLen = coap_get_tcp_header_length_for_transport(transport);
+    size_t copyLen = 0;
+
+    // HEADER
+    if (svritem->len < headerLen)
+    {
+        copyLen = headerLen - svritem->len;
+        if (inLen < copyLen)
+        {
+            copyLen = inLen;
+        }
+
+        //read required bytes to have full CoAP header
+        memcpy(svritem->data + svritem->len, inBuffer, copyLen);
+        svritem->len += copyLen;
+        inBuffer += copyLen;
+        inLen -= copyLen;
+
+        //if not enough data received - read them on next CAFillHeader() call
+        if (svritem->len < headerLen)
         {
-            return true;
+            *data = inBuffer;
+            *dataLength = inLen;
+            OIC_LOG(DEBUG, TAG, "CoAP header received partially. Wait for rest header data");
+            return CA_STATUS_OK;
         }
+
+        //calculate CoAP message length
+        svritem->totalLen = CAGetTotalLengthFromHeader(svritem->data);
+
+        // allocate required memory
+        unsigned char *buffer = OICRealloc(svritem->data, svritem->totalLen);
+        if (NULL == buffer)
+        {
+            OIC_LOG(ERROR, TAG, "OICRealloc - out of memory");
+            return CA_MEMORY_ALLOC_FAILED;
+        }
+        svritem->data = buffer;
     }
 
-    return false;
+    // PAYLOAD
+    if (inLen > 0)
+    {
+        // read required bytes to have full CoAP payload
+        copyLen = svritem->totalLen - svritem->len;
+        if (inLen < copyLen)
+        {
+            copyLen = inLen;
+        }
+
+        //read required bytes to have full CoAP header
+        memcpy(svritem->data + svritem->len, inBuffer, copyLen);
+        svritem->len += copyLen;
+        inBuffer += copyLen;
+        inLen -= copyLen;
+    }
+
+    *data = inBuffer;
+    *dataLength = inLen;
+
+    OIC_LOG_V(DEBUG, TAG, "after-datalength : %u", *dataLength);
+    OIC_LOG_V(DEBUG, TAG, "Out %s", __func__);
+    return CA_STATUS_OK;
 }
-#endif
 
 static void CAReceiveMessage(int fd)
 {
-    // #1. get remote device information from file descriptor.
+    CAResult_t res = CA_STATUS_OK;
+
+    //get remote device information from file descriptor.
     size_t index = 0;
     CATCPSessionInfo_t *svritem = CAGetSessionInfoFromFD(fd, &index);
     if (!svritem)
@@ -403,76 +519,110 @@ static void CAReceiveMessage(int fd)
         return;
     }
 
-    // #2. allocate memory for message header (CoAP header size because it is bigger)
-    svritem->data = (unsigned char *) OICCalloc(1, COAP_MAX_HEADER_SIZE);
-    if (!svritem->data)
-    {
-        OIC_LOG(ERROR, TAG, "out of memory");
-        goto error;
-    }
-
-    // #3. read data (assume TLS header) from remote device.
-    RECV(fd, svritem, svritem->data, TLS_HEADER_SIZE, 0);
+    // read data
+    int len = 0;
 
-#ifdef __WITH_TLS__
-    if (CAIsTlsMessage(svritem))
+    if (svritem->sep.endpoint.flags & CA_SECURE)
     {
-        // #4.1 get tls body length from tls header. [3][4] bytes are length of tls body in header
-        unsigned int message_length = (unsigned int)((svritem->data[3] << 8) | svritem->data[4]);
-        OIC_LOG_V(DEBUG, TAG, "%s: message_length = %d", __func__, message_length);
+        svritem->protocol = TLS;
 
-        REALLOC(svritem->data, message_length + TLS_HEADER_SIZE);
+#ifdef __WITH_TLS__
+        size_t nbRead = 0;
+        size_t tlsLength = 0;
 
-        RECV(fd, svritem, svritem->data, message_length, 0);
+        if (TLS_HEADER_SIZE > svritem->tlsLen)
+        {
+            nbRead = TLS_HEADER_SIZE - svritem->tlsLen;
+        }
+        else
+        {
+            //[3][4] bytes in tls header are tls payload length
+            tlsLength = TLS_HEADER_SIZE +
+                            (size_t)((svritem->tlsdata[3] << 8) | svritem->tlsdata[4]);
+            OIC_LOG_V(DEBUG, TAG, "total tls length = %u", tlsLength);
+            if (tlsLength > sizeof(svritem->tlsdata))
+            {
+                OIC_LOG_V(ERROR, TAG, "total tls length is too big (buffer size : %u)",
+                                    sizeof(svritem->tlsdata));
+                if (CA_STATUS_OK != CAcloseSslConnection(&svritem->sep.endpoint))
+                {
+                    OIC_LOG(ERROR, TAG, "Failed to close TLS session");
+                }
+                CASearchAndDeleteTCPSession(&(svritem->sep.endpoint));
+                return;
+            }
+            nbRead = tlsLength - svritem->tlsLen;
+        }
 
-        int ret = CAdecryptTls(&svritem->sep, (uint8_t *)svritem->data, svritem->len);
+        len = recv(fd, svritem->tlsdata + svritem->tlsLen, nbRead, 0);
+        if (len < 0)
+        {
+            OIC_LOG_V(ERROR, TAG, "recv failed %s", strerror(errno));
+            res = CA_RECEIVE_FAILED;
+        }
+        else if (0 == len)
+        {
+            OIC_LOG(INFO, TAG, "Received disconnect from peer. Close connection");
+            svritem->state = DISCONNECTED;
+            res = CA_DESTINATION_DISCONNECTED;
+        }
+        else
+        {
+            svritem->tlsLen += len;
+            OIC_LOG_V(DEBUG, TAG, "nb_read : %u bytes , recv() : %d bytes, svritem->tlsLen : %u bytes",
+                                nbRead, len, svritem->tlsLen);
+            if (tlsLength > 0 && tlsLength == svritem->tlsLen)
+            {
+                //when successfully read data - pass them to callback.
+                res = CAdecryptSsl(&svritem->sep, (uint8_t *)svritem->tlsdata, svritem->tlsLen);
+                svritem->tlsLen = 0;
+                OIC_LOG_V(INFO, TAG, "%s: CAdecryptSsl returned %d", __func__, res);
+            }
+        }
+#endif
 
-        OIC_LOG_V(DEBUG, TAG, "%s: CAdecryptTls returned %d", __func__, ret);
-        goto success;
     }
     else
-#endif
     {
-        // #4.2 Seems CoAP data received. read full coap header.
-        coap_transport_type transport = coap_get_tcp_header_type_from_initbyte(svritem->data[0] >> 4);
-
-        size_t headerLen = coap_get_tcp_header_length_for_transport(transport);
+        svritem->protocol = COAP;
 
-        if (svritem->len < headerLen)
+        // svritem->tlsdata can also be used as receiving buffer in case of raw tcp
+        len = recv(fd, svritem->tlsdata, sizeof(svritem->tlsdata), 0);
+        if (len < 0)
         {
-            // read required bytes to have full CoAP header
-            // usually it is 1 bytes (COAP_MAX_HEADER_SIZE - TLS_HEADER_SIZE)
-            RECV(fd, svritem, svritem->data, headerLen - svritem->len, 0);
+            OIC_LOG_V(ERROR, TAG, "recv failed %s", strerror(errno));
+            res = CA_RECEIVE_FAILED;
         }
-
-        // #4.3 Calculate CoAP message length and read it
-        size_t total_length = CAGetTotalLengthFromHeader(svritem->data);
-        REALLOC(svritem->data, total_length);
-
-        RECV(fd, svritem, svritem->data, total_length - svritem->len, 0);
-
-        // #4.4. pass the received data information to upper layer.
-        if (g_packetReceivedCallback)
+        else if (0 == len)
         {
-            svritem->sep.endpoint.adapter = CA_ADAPTER_TCP;
-            g_packetReceivedCallback(&svritem->sep, svritem->data, svritem->len);
+            OIC_LOG(INFO, TAG, "Received disconnect from peer. Close connection");
+            res = CA_DESTINATION_DISCONNECTED;
+        }
+        else
+        {
+            OIC_LOG_V(DEBUG, TAG, "recv() : %d bytes", len);
+            //when successfully read data - pass them to callback.
+            if (g_packetReceivedCallback)
+            {
+                res = g_packetReceivedCallback(&svritem->sep, svritem->tlsdata, len);
+            }
         }
-        goto success;
     }
 
-    error:
-    CADisconnectTCPSession(svritem, index);
-
-    success:
-    // initialize data info to receive next message.
-    OICFree(svritem->data);
-    svritem->data = NULL;
-    svritem->len = 0;
+    //disconnect session and clean-up data if any error occurs
+    if (res != CA_STATUS_OK)
+    {
+        if (CA_STATUS_OK != CATCPDisconnectSession(&svritem->sep.endpoint))
+        {
+            OIC_LOG(ERROR, TAG, "Failed to disconnect TCP session");
+        }
 
-    return;
+        CASearchAndDeleteTCPSession(&svritem->sep.endpoint);
+        return;
+    }
 }
 
-static void CAWakeUpForReadFdsUpdate(const char *host)
+static ssize_t CAWakeUpForReadFdsUpdate(const char *host)
 {
     if (caglobals.tcp.connectionFds[1] != -1)
     {
@@ -486,7 +636,9 @@ static void CAWakeUpForReadFdsUpdate(const char *host)
         {
             OIC_LOG_V(DEBUG, TAG, "write failed: %s", strerror(errno));
         }
+        return len;
     }
+    return -1;
 }
 
 static CAResult_t CATCPConvertNameToAddr(int family, const char *host, uint16_t port,
@@ -528,15 +680,21 @@ static CAResult_t CATCPConvertNameToAddr(int family, const char *host, uint16_t
     return CA_STATUS_OK;
 }
 
-static int CATCPCreateSocket(int family, CATCPSessionInfo_t *svritem)
+static CAResult_t CATCPCreateSocket(int family, CATCPSessionInfo_t *svritem)
 {
+    VERIFY_NON_NULL(svritem, TAG, "svritem is NULL");
+
+    OIC_LOG_V(INFO, TAG, "try to connect with [%s:%u]",
+              svritem->sep.endpoint.addr, svritem->sep.endpoint.port);
+
     // #1. create tcp socket.
     int fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
     if (-1 == fd)
     {
         OIC_LOG_V(ERROR, TAG, "create socket failed: %s", strerror(errno));
-        return -1;
+        return CA_SOCKET_OPERATION_FAILED;
     }
+    svritem->fd = fd;
 
     // #2. convert address from string to binary.
     struct sockaddr_storage sa = { .ss_family = family };
@@ -544,8 +702,8 @@ static int CATCPCreateSocket(int family, CATCPSessionInfo_t *svritem)
                                             svritem->sep.endpoint.port, &sa);
     if (CA_STATUS_OK != res)
     {
-        close(fd);
-        return -1;
+        OIC_LOG(ERROR, TAG, "convert name to sockaddr failed");
+        return CA_SOCKET_OPERATION_FAILED;
     }
 
     // #3. set socket length.
@@ -568,20 +726,28 @@ static int CATCPCreateSocket(int family, CATCPSessionInfo_t *svritem)
     if (connect(fd, (struct sockaddr *)&sa, socklen) < 0)
     {
         OIC_LOG_V(ERROR, TAG, "failed to connect socket, %s", strerror(errno));
-        close(fd);
-        return -1;
+        CALogSendStateInfo(svritem->sep.endpoint.adapter, svritem->sep.endpoint.addr,
+                           svritem->sep.endpoint.port, 0, false, strerror(errno));
+        return CA_SOCKET_OPERATION_FAILED;
     }
 
-    OIC_LOG(DEBUG, TAG, "connect socket success");
-    CAWakeUpForReadFdsUpdate(svritem->sep.endpoint.addr);
-    return fd;
+    OIC_LOG(INFO, TAG, "connect socket success");
+    svritem->state = CONNECTED;
+    CHECKFD(svritem->fd);
+    ssize_t len = CAWakeUpForReadFdsUpdate(svritem->sep.endpoint.addr);
+    if (-1 == len)
+    {
+        OIC_LOG(ERROR, TAG, "wakeup receive thread failed");
+        return CA_SOCKET_OPERATION_FAILED;
+    }
+    return CA_STATUS_OK;
 }
 
-static int CACreateAcceptSocket(int family, CASocket_t *sock)
+static CASocketFd_t CACreateAcceptSocket(int family, CASocket_t *sock)
 {
     VERIFY_NON_NULL_RET(sock, TAG, "sock", -1);
 
-    if (sock->fd != -1)
+    if (OC_INVALID_SOCKET != sock->fd)
     {
         OIC_LOG(DEBUG, TAG, "accept socket created already");
         return sock->fd;
@@ -591,7 +757,7 @@ static int CACreateAcceptSocket(int family, CASocket_t *sock)
     struct sockaddr_storage server = { .ss_family = family };
 
     int fd = socket(family, SOCK_STREAM, IPPROTO_TCP);
-    if (fd < 0)
+    if (OC_INVALID_SOCKET == fd)
     {
         OIC_LOG(ERROR, TAG, "Failed to create socket");
         goto exit;
@@ -599,13 +765,16 @@ static int CACreateAcceptSocket(int family, CASocket_t *sock)
 
     if (family == AF_INET6)
     {
-        // the socket is restricted to sending and receiving IPv6 packets only.
+        // the socket is restricted to sending and receiving IPv6 packets only.
         int on = 1;
+//TODO: enable once IPv6 is supported
+#ifndef __TIZENRT__
         if (-1 == setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on)))
         {
             OIC_LOG_V(ERROR, TAG, "IPV6_V6ONLY failed: %s", strerror(errno));
             goto exit;
         }
+#endif
         ((struct sockaddr_in6 *)&server)->sin6_port = htons(sock->port);
         socklen = sizeof (struct sockaddr_in6);
     }
@@ -634,7 +803,17 @@ static int CACreateAcceptSocket(int family, CASocket_t *sock)
         goto exit;
     }
 
-    if (!sock->port)  // return the assigned port
+    if (sock->port) // use the given port
+    {
+        int on = 1;
+        if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, OPTVAL_T(&on), sizeof (on)))
+        {
+            OIC_LOG_V(ERROR, TAG, "SO_REUSEADDR failed: %s", strerror(errno));
+            close(fd);
+            return OC_INVALID_SOCKET;
+        }
+    }
+    else  // return the assigned port
     {
         if (-1 == getsockname(fd, (struct sockaddr *)&server, &socklen))
         {
@@ -653,12 +832,26 @@ exit:
     {
         close(fd);
     }
-    return -1;
+    return OC_INVALID_SOCKET;
 }
 
 static void CAInitializePipe(int *fds)
 {
     int ret = pipe(fds);
+// TODO: Remove temporary workaround once F_GETFD / F_SETFD support is in TizenRT
+/* Temporary workaround: By pass F_GETFD / F_SETFD */
+#ifdef __TIZENRT__
+    if (-1 == ret)
+    {
+        close(fds[1]);
+        close(fds[0]);
+
+        fds[0] = -1;
+        fds[1] = -1;
+
+        OIC_LOG_V(ERROR, TAG, "pipe failed: %s", strerror(errno));
+    }
+#else
     if (-1 != ret)
     {
         ret = fcntl(fds[0], F_GETFD);
@@ -685,6 +878,7 @@ static void CAInitializePipe(int *fds)
             OIC_LOG_V(ERROR, TAG, "pipe failed: %s", strerror(errno));
         }
     }
+#endif
 }
 
 #define NEWSOCKET(FAMILY, NAME) \
@@ -696,13 +890,47 @@ static void CAInitializePipe(int *fds)
     } \
     CHECKFD(caglobals.tcp.NAME.fd);
 
+void CATCPInitializeSocket()
+{
+#ifndef __WITH_TLS__
+        NEWSOCKET(AF_INET, ipv4);
+#else
+        NEWSOCKET(AF_INET, ipv4s);
+#endif
+
+//TODO Enable once TizenRT supports IPv6
+#ifndef __TIZENRT__
+#ifndef __WITH_TLS__
+        NEWSOCKET(AF_INET6, ipv6);
+#else
+        NEWSOCKET(AF_INET6, ipv6s);
+#endif
+#endif
+#ifndef __WITH_TLS__
+        OIC_LOG_V(DEBUG, TAG, "IPv4 socket fd=%d, port=%d",
+                  caglobals.tcp.ipv4.fd, caglobals.tcp.ipv4.port);
+        OIC_LOG_V(DEBUG, TAG, "IPv6 socket fd=%d, port=%d",
+                  caglobals.tcp.ipv6.fd, caglobals.tcp.ipv6.port);
+#else
+        OIC_LOG_V(DEBUG, TAG, "IPv4 secure socket fd=%d, port=%d",
+                  caglobals.tcp.ipv4s.fd, caglobals.tcp.ipv4s.port);
+        OIC_LOG_V(DEBUG, TAG, "IPv6 secure socket fd=%d, port=%d",
+                  caglobals.tcp.ipv6s.fd, caglobals.tcp.ipv6s.port);
+#endif
+}
+
 CAResult_t CATCPStartServer(const ca_thread_pool_t threadPool)
 {
+    oc_mutex_lock(g_mutexObjectList);
     if (caglobals.tcp.started)
     {
+        oc_mutex_unlock(g_mutexObjectList);
+        OIC_LOG(INFO, TAG, "Adapter is started already");
         return CA_STATUS_OK;
     }
 
+    g_threadPool = threadPool;
+
     if (!caglobals.tcp.ipv4tcpenabled)
     {
         caglobals.tcp.ipv4tcpenabled = true;    // only needed to run CA tests
@@ -712,100 +940,108 @@ CAResult_t CATCPStartServer(const ca_thread_pool_t threadPool)
         caglobals.tcp.ipv6tcpenabled = true;    // only needed to run CA tests
     }
 
-    CAResult_t res = CATCPCreateMutex();
-    if (CA_STATUS_OK == res)
-    {
-        res = CATCPCreateCond();
-    }
-    if (CA_STATUS_OK != res)
-    {
-        OIC_LOG(ERROR, TAG, "failed to create mutex/cond");
-        return res;
-    }
-
-    ca_mutex_lock(g_mutexObjectList);
+    caglobals.tcp.terminate = false;
     if (!caglobals.tcp.svrlist)
     {
         caglobals.tcp.svrlist = u_arraylist_create();
     }
-    ca_mutex_unlock(g_mutexObjectList);
 
     if (caglobals.server)
     {
-        NEWSOCKET(AF_INET, ipv4);
-        NEWSOCKET(AF_INET6, ipv6);
-        OIC_LOG_V(DEBUG, TAG, "IPv4 socket fd=%d, port=%d",
-                  caglobals.tcp.ipv4.fd, caglobals.tcp.ipv4.port);
-        OIC_LOG_V(DEBUG, TAG, "IPv6 socket fd=%d, port=%d",
-                  caglobals.tcp.ipv6.fd, caglobals.tcp.ipv6.port);
+        CATCPInitializeSocket();
     }
-
+#ifndef __TIZENRT__
     // create pipe for fast shutdown
     CAInitializePipe(caglobals.tcp.shutdownFds);
     CHECKFD(caglobals.tcp.shutdownFds[0]);
     CHECKFD(caglobals.tcp.shutdownFds[1]);
-
+#endif
     // create pipe for connection event
     CAInitializePipe(caglobals.tcp.connectionFds);
     CHECKFD(caglobals.tcp.connectionFds[0]);
     CHECKFD(caglobals.tcp.connectionFds[1]);
 
-    caglobals.tcp.terminate = false;
-    res = ca_thread_pool_add_task(threadPool, CAReceiveHandler, NULL);
+    CAResult_t res = CA_STATUS_OK;
+#ifndef __TIZENRT__
+    res = ca_thread_pool_add_task(g_threadPool, CAReceiveHandler, NULL, &g_recvThreadId);
+#else
+    res = ca_thread_pool_add_task(g_threadPool, CAReceiveHandler, NULL, &g_recvThreadId,
+                                 "IoT_TCPReceive", CONFIG_IOTIVITY_TCPRECEIVE_PTHREAD_STACKSIZE);
+#endif
     if (CA_STATUS_OK != res)
     {
+        g_recvThreadId = 0;
+        oc_mutex_unlock(g_mutexObjectList);
         OIC_LOG(ERROR, TAG, "thread_pool_add_task failed");
+        CATCPStopServer();
         return res;
     }
-    OIC_LOG(DEBUG, TAG, "CAReceiveHandler thread started successfully.");
 
     caglobals.tcp.started = true;
+    oc_mutex_unlock(g_mutexObjectList);
+
+    OIC_LOG(INFO, TAG, "CAReceiveHandler thread started successfully.");
     return CA_STATUS_OK;
 }
 
 void CATCPStopServer()
 {
-    // mutex lock
-    ca_mutex_lock(g_mutexObjectList);
+    oc_mutex_lock(g_mutexObjectList);
+    if (caglobals.tcp.terminate)
+    {
+        oc_mutex_unlock(g_mutexObjectList);
+        OIC_LOG(INFO, TAG, "Adapter is not enabled");
+        return;
+    }
 
-    // set terminate flag
+    // set terminate flag.
     caglobals.tcp.terminate = true;
 
-    if (caglobals.tcp.shutdownFds[1] != -1)
+    // close accept socket.
+#ifndef __WITH_TLS__
+    CLOSE_SOCKET(ipv4);
+    CLOSE_SOCKET(ipv6);
+#else
+    CLOSE_SOCKET(ipv4s);
+    CLOSE_SOCKET(ipv6s);
+#endif
+
+    close(caglobals.tcp.connectionFds[1]);
+    close(caglobals.tcp.connectionFds[0]);
+    caglobals.tcp.connectionFds[1] = OC_INVALID_SOCKET;
+    caglobals.tcp.connectionFds[0] = OC_INVALID_SOCKET;
+#ifndef __TIZENRT__
+    if (caglobals.tcp.shutdownFds[1] != OC_INVALID_SOCKET)
     {
         close(caglobals.tcp.shutdownFds[1]);
+        caglobals.tcp.shutdownFds[1] = OC_INVALID_SOCKET;
         // receive thread will stop immediately
     }
-
-    if (caglobals.tcp.connectionFds[1] != -1)
-    {
-        close(caglobals.tcp.connectionFds[1]);
-    }
-
+#endif
     if (caglobals.tcp.started)
     {
-        ca_cond_wait(g_condObjectList, g_mutexObjectList);
+        oc_cond_wait(g_condObjectList, g_mutexObjectList);
+        caglobals.tcp.started = false;
     }
-    caglobals.tcp.started = false;
-
-    // mutex unlock
-    ca_mutex_unlock(g_mutexObjectList);
-
-    if (-1 != caglobals.tcp.ipv4.fd)
+#ifndef __TIZENRT__
+    if (caglobals.tcp.shutdownFds[0] != OC_INVALID_SOCKET)
     {
-        close(caglobals.tcp.ipv4.fd);
-        caglobals.tcp.ipv4.fd = -1;
+        close(caglobals.tcp.shutdownFds[0]);
+        caglobals.tcp.shutdownFds[0] = OC_INVALID_SOCKET;
     }
-
-    if (-1 != caglobals.tcp.ipv6.fd)
+#endif
+    CAResult_t res = ca_thread_pool_remove_task(g_threadPool, g_recvThreadId);
+    if (CA_STATUS_OK != res)
     {
-        close(caglobals.tcp.ipv6.fd);
-        caglobals.tcp.ipv6.fd = -1;
+        OIC_LOG(ERROR, TAG, "ca_thread_pool_remove_task failed");
     }
+    g_recvThreadId = 0;
+    oc_mutex_unlock(g_mutexObjectList);
 
     CATCPDisconnectAll();
-    CATCPDestroyMutex();
-    CATCPDestroyCond();
+    sleep(1);
+
+    OIC_LOG(INFO, TAG, "Adapter terminated successfully");
 }
 
 void CATCPSetPacketReceiveCallback(CATCPPacketReceivedCallback callback)
@@ -818,55 +1054,85 @@ void CATCPSetConnectionChangedCallback(CATCPConnectionHandleCallback connHandler
     g_connectionCallback = connHandler;
 }
 
-static void sendData(const CAEndpoint_t *endpoint, const void *data,
-                     size_t dlen, const char *fam)
+size_t CACheckPayloadLengthFromHeader(const void *data, size_t dlen)
 {
-    // #1. get TCP Server object from list
-    size_t index = 0;
-    CATCPSessionInfo_t *svritem = CAGetTCPSessionInfoFromEndpoint(endpoint, &index);
-    if (!svritem)
+    VERIFY_NON_NULL_RET(data, TAG, "data", -1);
+
+    coap_transport_t transport = coap_get_tcp_header_type_from_initbyte(
+            ((unsigned char *)data)[0] >> 4);
+
+    coap_pdu_t *pdu = coap_new_pdu2(transport, dlen);
+    if (!pdu)
     {
-        // if there is no connection info, connect to TCP Server
-        svritem = CAConnectTCPSession(endpoint);
-        if (!svritem)
-        {
-            OIC_LOG(ERROR, TAG, "Failed to create TCP server object");
-            if (g_tcpErrorHandler)
-            {
-                g_tcpErrorHandler(endpoint, data, dlen, CA_SEND_FAILED);
-            }
-            return;
-        }
+        OIC_LOG(ERROR, TAG, "outpdu is null");
+        OIC_LOG_V(ERROR, TAG, "data length: %zu", dlen);
+        return 0;
+    }
+
+    int ret = coap_pdu_parse2((unsigned char *) data, dlen, pdu, transport);
+    if (0 >= ret)
+    {
+        OIC_LOG(ERROR, TAG, "pdu parse failed");
+        coap_delete_pdu(pdu);
+        return 0;
     }
 
-    // #2. check connection state
-    if (svritem->fd < 0)
+    size_t payloadLen = 0;
+    size_t headerSize = coap_get_tcp_header_length_for_transport(transport);
+    OIC_LOG_V(DEBUG, TAG, "headerSize : %zu, pdu length : %d",
+              headerSize, pdu->length);
+    if (pdu->length > headerSize)
+    {
+        payloadLen = (unsigned char *) pdu->hdr + pdu->length - pdu->data;
+    }
+
+    OICFree(pdu);
+
+    return payloadLen;
+}
+
+static ssize_t sendData(const CAEndpoint_t *endpoint, const void *data,
+                        size_t dlen, const char *fam)
+{
+    OIC_LOG_V(INFO, TAG, "The length of data that needs to be sent is %zu bytes", dlen);
+
+    // #1. find a session info from list.
+    CASocketFd_t sockFd = CAGetSocketFDFromEndpoint(endpoint);
+    if (OC_INVALID_SOCKET == sockFd)
     {
-        // if file descriptor value is wrong, remove TCP Server info from list
-        OIC_LOG(ERROR, TAG, "Failed to connect to TCP server");
-        CADisconnectTCPSession(svritem, index);
-        if (g_tcpErrorHandler)
+        // if there is no connection info, connect to remote device.
+        sockFd = CAConnectTCPSession(endpoint);
+        if (OC_INVALID_SOCKET == sockFd)
         {
-            g_tcpErrorHandler(endpoint, data, dlen, CA_SEND_FAILED);
+            OIC_LOG(ERROR, TAG, "Failed to create tcp session object");
+            return -1;
         }
-        return;
     }
 
-    // #4. send data to TCP Server
+    // #2. send data to remote device.
     ssize_t remainLen = dlen;
     do
     {
-        ssize_t len = send(svritem->fd, data, remainLen, 0);
+        size_t sendCounter = 0;
+#ifdef MSG_NOSIGNAL
+        ssize_t len = send(sockFd, data, remainLen, MSG_DONTWAIT | MSG_NOSIGNAL);
+#else
+        ssize_t len = send(sockFd, data, remainLen, MSG_DONTWAIT);
+#endif
         if (-1 == len)
         {
-            if (EWOULDBLOCK != errno)
+            if (EWOULDBLOCK != errno && EAGAIN != errno)
             {
                 OIC_LOG_V(ERROR, TAG, "unicast ipv4tcp sendTo failed: %s", strerror(errno));
-                if (g_tcpErrorHandler)
-                {
-                    g_tcpErrorHandler(endpoint, data, dlen, CA_SEND_FAILED);
-                }
-                return;
+                CALogSendStateInfo(endpoint->adapter, endpoint->addr, endpoint->port,
+                                   len, false, strerror(errno));
+                return len;
+            }
+            sendCounter++;
+            OIC_LOG_V(WARNING, TAG, "send blocked. trying %zu attempt from 100", sendCounter);
+            if(sendCounter >= 100)
+            {
+                return len;
             }
             continue;
         }
@@ -874,26 +1140,31 @@ static void sendData(const CAEndpoint_t *endpoint, const void *data,
         remainLen -= len;
     } while (remainLen > 0);
 
+#ifndef TB_LOG
+    (void)fam;
+#endif
     OIC_LOG_V(INFO, TAG, "unicast %stcp sendTo is successful: %zu bytes", fam, dlen);
+    CALogSendStateInfo(endpoint->adapter, endpoint->addr, endpoint->port,
+                       dlen, true, NULL);
+    return dlen;
 }
 
-void CATCPSendData(CAEndpoint_t *endpoint, const void *data, uint32_t datalen,
-                   bool isMulticast)
+ssize_t CATCPSendData(CAEndpoint_t *endpoint, const void *data, size_t datalen)
 {
-    VERIFY_NON_NULL_VOID(endpoint, TAG, "endpoint is NULL");
-    VERIFY_NON_NULL_VOID(data, TAG, "data is NULL");
+    VERIFY_NON_NULL_RET(endpoint, TAG, "endpoint is NULL", -1);
+    VERIFY_NON_NULL_RET(data, TAG, "data is NULL", -1);
 
-    if (!isMulticast)
+    if (caglobals.tcp.ipv6tcpenabled && (endpoint->flags & CA_IPV6))
     {
-        if (caglobals.tcp.ipv6tcpenabled && (endpoint->flags & CA_IPV6))
-        {
-            sendData(endpoint, data, datalen, "ipv6");
-        }
-        if (caglobals.tcp.ipv4tcpenabled && (endpoint->flags & CA_IPV4))
-        {
-            sendData(endpoint, data, datalen, "ipv4");
-        }
+        return sendData(endpoint, data, datalen, "ipv6");
     }
+    if (caglobals.tcp.ipv4tcpenabled && (endpoint->flags & CA_IPV4))
+    {
+        return sendData(endpoint, data, datalen, "ipv4");
+    }
+
+    OIC_LOG(ERROR, TAG, "Not supported transport flags");
+    return -1;
 }
 
 CAResult_t CAGetTCPInterfaceInformation(CAEndpoint_t **info, uint32_t *size)
@@ -904,35 +1175,27 @@ CAResult_t CAGetTCPInterfaceInformation(CAEndpoint_t **info, uint32_t *size)
     return CA_NOT_SUPPORTED;
 }
 
-CATCPSessionInfo_t *CAConnectTCPSession(const CAEndpoint_t *endpoint)
+CASocketFd_t CAConnectTCPSession(const CAEndpoint_t *endpoint)
 {
-    VERIFY_NON_NULL_RET(endpoint, TAG, "endpoint is NULL", NULL);
+    VERIFY_NON_NULL_RET(endpoint, TAG, "endpoint is NULL", OC_INVALID_SOCKET);
 
     // #1. create TCP server object
     CATCPSessionInfo_t *svritem = (CATCPSessionInfo_t *) OICCalloc(1, sizeof (*svritem));
     if (!svritem)
     {
         OIC_LOG(ERROR, TAG, "Out of memory");
-        return NULL;
+        return OC_INVALID_SOCKET;
     }
     memcpy(svritem->sep.endpoint.addr, endpoint->addr, sizeof(svritem->sep.endpoint.addr));
     svritem->sep.endpoint.adapter = endpoint->adapter;
     svritem->sep.endpoint.port = endpoint->port;
     svritem->sep.endpoint.flags = endpoint->flags;
     svritem->sep.endpoint.ifindex = endpoint->ifindex;
+    svritem->state = CONNECTING;
+    svritem->isClient = true;
 
-    // #2. create the socket and connect to TCP server
-    int family = (svritem->sep.endpoint.flags & CA_IPV6) ? AF_INET6 : AF_INET;
-    int fd = CATCPCreateSocket(family, svritem);
-    if (-1 == fd)
-    {
-        OICFree(svritem);
-        return NULL;
-    }
-
-    // #3. add TCP connection info to list
-    svritem->fd = fd;
-    ca_mutex_lock(g_mutexObjectList);
+    // #2. add TCP connection info to list
+    oc_mutex_lock(g_mutexObjectList);
     if (caglobals.tcp.svrlist)
     {
         bool res = u_arraylist_add(caglobals.tcp.svrlist, svritem);
@@ -941,70 +1204,87 @@ CATCPSessionInfo_t *CAConnectTCPSession(const CAEndpoint_t *endpoint)
             OIC_LOG(ERROR, TAG, "u_arraylist_add failed.");
             close(svritem->fd);
             OICFree(svritem);
-            ca_mutex_unlock(g_mutexObjectList);
-            return NULL;
+            oc_mutex_unlock(g_mutexObjectList);
+            return OC_INVALID_SOCKET;
         }
     }
-    ca_mutex_unlock(g_mutexObjectList);
+    oc_mutex_unlock(g_mutexObjectList);
 
-    CHECKFD(fd);
+    // #3. create the socket and connect to TCP server
+    int family = (svritem->sep.endpoint.flags & CA_IPV6) ? AF_INET6 : AF_INET;
+    if (CA_STATUS_OK != CATCPCreateSocket(family, svritem))
+    {
+        return OC_INVALID_SOCKET;
+    }
 
-    // pass the connection information to CA Common Layer.
+    // #4. pass the connection information to CA Common Layer.
     if (g_connectionCallback)
     {
-        g_connectionCallback(&(svritem->sep.endpoint), true);
+        g_connectionCallback(&(svritem->sep.endpoint), true, svritem->isClient);
     }
 
-    return svritem;
+    return svritem->fd;
 }
 
-CAResult_t CADisconnectTCPSession(CATCPSessionInfo_t *svritem, size_t index)
+CAResult_t CADisconnectTCPSession(size_t index)
 {
-    VERIFY_NON_NULL(svritem, TAG, "svritem is NULL");
-
-    ca_mutex_lock(g_mutexObjectList);
-
-    // close the socket and remove TCP connection info in list
-    if (svritem->fd >= 0)
+    CATCPSessionInfo_t *removedData = u_arraylist_remove(caglobals.tcp.svrlist, index);
+    if (!removedData)
     {
-        close(svritem->fd);
+        OIC_LOG(DEBUG, TAG, "there is no data to be removed");
+        return CA_STATUS_OK;
     }
-    u_arraylist_remove(caglobals.tcp.svrlist, index);
-    OICFree(svritem->data);
-    svritem->data = NULL;
 
-    // pass the connection information to CA Common Layer.
-    if (g_connectionCallback)
+    // close the socket and remove session info in list.
+    if (removedData->fd >= 0)
     {
-        g_connectionCallback(&(svritem->sep.endpoint), false);
+        shutdown(removedData->fd, SHUT_RDWR);
+        close(removedData->fd);
+        removedData->fd = -1;
+        removedData->state = (CONNECTED == removedData->state) ?
+                                    DISCONNECTED : removedData->state;
+
+        // pass the connection information to CA Common Layer.
+        if (g_connectionCallback && DISCONNECTED == removedData->state)
+        {
+            g_connectionCallback(&(removedData->sep.endpoint), false, removedData->isClient);
+        }
     }
+    OICFree(removedData->data);
+    removedData->data = NULL;
+
+    OICFree(removedData);
+    removedData = NULL;
 
-    OICFree(svritem);
-    ca_mutex_unlock(g_mutexObjectList);
+    OIC_LOG(DEBUG, TAG, "data is removed from session list");
 
+    if (caglobals.server && MAX_CONNECTION_COUNTS == u_arraylist_length(caglobals.tcp.svrlist) + 1)
+    {
+        CATCPInitializeSocket();
+    }
     return CA_STATUS_OK;
 }
 
 void CATCPDisconnectAll()
 {
-    ca_mutex_lock(g_mutexObjectList);
-    uint32_t length = u_arraylist_length(caglobals.tcp.svrlist);
+    oc_mutex_lock(g_mutexObjectList);
 
-    CATCPSessionInfo_t *svritem = NULL;
-    for (size_t i = 0; i < length; i++)
+    uint32_t length = u_arraylist_length(caglobals.tcp.svrlist);
+    for (ssize_t index = length; index > 0; index--)
     {
-        svritem = (CATCPSessionInfo_t *) u_arraylist_get(caglobals.tcp.svrlist, i);
-        if (svritem && svritem->fd >= 0)
-        {
-            shutdown(svritem->fd, SHUT_RDWR);
-            close(svritem->fd);
-
-            OICFree(svritem->data);
-            svritem->data = NULL;
-        }
+        // disconnect session from remote device.
+        CADisconnectTCPSession(index - 1);
     }
+
     u_arraylist_destroy(caglobals.tcp.svrlist);
-    ca_mutex_unlock(g_mutexObjectList);
+    caglobals.tcp.svrlist = NULL;
+
+    oc_mutex_unlock(g_mutexObjectList);
+
+#ifdef __WITH_TLS__
+    CAcloseSslConnectionAll(CA_ADAPTER_TCP);
+#endif
+
 }
 
 CATCPSessionInfo_t *CAGetTCPSessionInfoFromEndpoint(const CAEndpoint_t *endpoint, size_t *index)
@@ -1012,6 +1292,8 @@ CATCPSessionInfo_t *CAGetTCPSessionInfoFromEndpoint(const CAEndpoint_t *endpoint
     VERIFY_NON_NULL_RET(endpoint, TAG, "endpoint is NULL", NULL);
     VERIFY_NON_NULL_RET(index, TAG, "index is NULL", NULL);
 
+    OIC_LOG_V(DEBUG, TAG, "Looking for [%s:%d]", endpoint->addr, endpoint->port);
+
     // get connection info from list
     uint32_t length = u_arraylist_length(caglobals.tcp.svrlist);
     for (size_t i = 0; i < length; i++)
@@ -1028,17 +1310,53 @@ CATCPSessionInfo_t *CAGetTCPSessionInfoFromEndpoint(const CAEndpoint_t *endpoint
                 && (svritem->sep.endpoint.port == endpoint->port)
                 && (svritem->sep.endpoint.flags & endpoint->flags))
         {
+            OIC_LOG(DEBUG, TAG, "Found in session list");
             *index = i;
             return svritem;
         }
     }
 
+    OIC_LOG(DEBUG, TAG, "Session not found");
     return NULL;
 }
 
+CASocketFd_t CAGetSocketFDFromEndpoint(const CAEndpoint_t *endpoint)
+{
+    VERIFY_NON_NULL_RET(endpoint, TAG, "endpoint is NULL", OC_INVALID_SOCKET);
+
+    OIC_LOG_V(DEBUG, TAG, "Looking for [%s:%d]", endpoint->addr, endpoint->port);
+
+    // get connection info from list.
+    oc_mutex_lock(g_mutexObjectList);
+    uint32_t length = u_arraylist_length(caglobals.tcp.svrlist);
+    for (size_t i = 0; i < length; i++)
+    {
+        CATCPSessionInfo_t *svritem = (CATCPSessionInfo_t *) u_arraylist_get(
+                caglobals.tcp.svrlist, i);
+        if (!svritem)
+        {
+            continue;
+        }
+
+        if (!strncmp(svritem->sep.endpoint.addr, endpoint->addr,
+                     sizeof(svritem->sep.endpoint.addr))
+                && (svritem->sep.endpoint.port == endpoint->port)
+                && (svritem->sep.endpoint.flags & endpoint->flags))
+        {
+            oc_mutex_unlock(g_mutexObjectList);
+            OIC_LOG(DEBUG, TAG, "Found in session list");
+            return svritem->fd;
+        }
+    }
+
+    oc_mutex_unlock(g_mutexObjectList);
+    OIC_LOG(DEBUG, TAG, "Session not found");
+    return OC_INVALID_SOCKET;
+}
+
 CATCPSessionInfo_t *CAGetSessionInfoFromFD(int fd, size_t *index)
 {
-    ca_mutex_lock(g_mutexObjectList);
+    oc_mutex_lock(g_mutexObjectList);
 
     // check from the last item.
     CATCPSessionInfo_t *svritem = NULL;
@@ -1050,21 +1368,41 @@ CATCPSessionInfo_t *CAGetSessionInfoFromFD(int fd, size_t *index)
         if (svritem && svritem->fd == fd)
         {
             *index = i;
-            ca_mutex_unlock(g_mutexObjectList);
+            oc_mutex_unlock(g_mutexObjectList);
             return svritem;
         }
     }
 
-    ca_mutex_unlock(g_mutexObjectList);
+    oc_mutex_unlock(g_mutexObjectList);
 
     return NULL;
 }
 
+CAResult_t CASearchAndDeleteTCPSession(const CAEndpoint_t *endpoint)
+{
+    oc_mutex_lock(g_mutexObjectList);
+
+    CAResult_t result = CA_STATUS_OK;
+    size_t index = 0;
+    CATCPSessionInfo_t *svritem = CAGetTCPSessionInfoFromEndpoint(endpoint, &index);
+    if (svritem)
+    {
+        result = CADisconnectTCPSession(index);
+        if (CA_STATUS_OK != result)
+        {
+            OIC_LOG_V(ERROR, TAG, "CADisconnectTCPSession failed, result[%d]", result);
+        }
+    }
+
+    oc_mutex_unlock(g_mutexObjectList);
+    return result;
+}
+
 size_t CAGetTotalLengthFromHeader(const unsigned char *recvBuffer)
 {
     OIC_LOG(DEBUG, TAG, "IN - CAGetTotalLengthFromHeader");
 
-    coap_transport_type transport = coap_get_tcp_header_type_from_initbyte(
+    coap_transport_t transport = coap_get_tcp_header_type_from_initbyte(
             ((unsigned char *)recvBuffer)[0] >> 4);
     size_t optPaylaodLen = coap_get_length_from_header((unsigned char *)recvBuffer,
                                                         transport);