add socket wrapper for at framework

you can use at framework to send/recv data in socket API
example: see examples\tcp_through_module_based_at_socket
project: see board\TencentOS_tiny_EVB_MX_Plus\KEIL\tcp_through_module_based_at_socket

net/socket_wrapper/include/tos_at_socket.h

@@ -0,0 +1,66 @@
+/*----------------------------------------------------------------------------
+ * Tencent is pleased to support the open source community by making TencentOS
+ * available.
+ *
+ * Copyright (C) 2019 THL A29 Limited, a Tencent company. All rights reserved.
+ * If you have downloaded a copy of the TencentOS binary from Tencent, please
+ * note that the TencentOS binary is licensed under the BSD 3-Clause License.
+ *
+ * If you have downloaded a copy of the TencentOS source code from Tencent,
+ * please note that TencentOS source code is licensed under the BSD 3-Clause
+ * License, except for the third-party components listed below which are
+ * subject to different license terms. Your integration of TencentOS into your
+ * own projects may require compliance with the BSD 3-Clause License, as well
+ * as the other licenses applicable to the third-party components included
+ * within TencentOS.
+ *---------------------------------------------------------------------------*/
+
+#ifndef  _TOS_AT_SOCKET_H_
+#define  _TOS_AT_SOCKET_H_
+
+#include "tos_at_socket_lib.h"
+#include "tos_at_socket_types.h"
+
+#define AF_INET             0
+
+#define AF_INET6            1
+
+#define AF_UNIX             2
+
+/* Provides sequenced, reliable, bidirectional, connection-mode byte streams, and may provide a transmission mechanism for out-of-band data. */
+#define SOCK_STREAM         0
+
+/* Provides datagrams, which are connectionless-mode, unreliable messages of fixed maximum length. */
+#define SOCK_DGRAM          1
+
+/* Peeks at an incoming message. The data is treated as unread and the next recv() or similar function shall still return this data. */
+#define MSG_PEEK            0x01
+
+/* Requests out-of-band data. The significance and semantics of out-of-band data are protocol-specific. */
+#define MSG_OOB             0x02
+
+/* On SOCK_STREAM sockets this requests that the function block until the full amount of data can be returned. The function may return the smaller amount of data if the socket is a message-based socket, if a signal is caught, if the connection is terminated, if MSG_PEEK was specified, or if an error is pending for the socket. */
+#define MSG_WAITALL         0x04
+
+int socket(int domain, int type, int protocol);
+
+int connect(int socket, const struct sockaddr *address, socklen_t address_len);
+
+int recv(int socket, void *buffer, size_t length, int flags);
+
+int recvfrom(int socket, void * buffer, size_t length, int flags, struct sockaddr *address, socklen_t *address_len);
+
+int send(int socket, const void *buffer, size_t length, int flags);
+
+int sendto(int socket, const void *message, size_t length, int flags, const struct sockaddr *dest_addr, socklen_t dest_len);
+
+int shutdown(int socket, int how);
+
+int read(int socket, void *buffer, size_t length);
+
+int close(int socket);
+
+int write(int socket, const void *buffer, size_t length);
+
+#endif /* _TOS_AT_SOCKET_H_ */
+