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/tos_at_socket_lib.c

@@ -0,0 +1,122 @@
+/*----------------------------------------------------------------------------
+ * 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.
+ *---------------------------------------------------------------------------*/
+
+#include "tos_at_socket_lib.h"
+
+s8_t
+inet_aton(const char *cp, struct in_addr *addr)
+{
+    u32_t val;
+    s32_t base, n;
+    char c;
+    u32_t parts[4];
+    u32_t* pp = parts;
+
+    c = *cp;
+    for (;;) {
+        /*
+         * Collect number up to ``.''.
+         * Values are specified as for C:
+         * 0x=hex, 0=octal, isdigit=decimal.
+         */
+        if (!isdigit(c))
+            return (0);
+        val = 0; base = 10;
+        if (c == '0') {
+            c = *++cp;
+            if (c == 'x' || c == 'X')
+                base = 16, c = *++cp;
+            else
+                base = 8;
+        }
+        for (;;) {
+            if (isdigit(c)) {
+                val = (val * base) + (s16_t)(c - '0');
+                c = *++cp;
+            } else if (base == 16 && isxdigit(c)) {
+                val = (val << 4) |
+                    (s16_t)(c + 10 - (islower(c) ? 'a' : 'A'));
+                c = *++cp;
+            } else
+            break;
+        }
+        if (c == '.') {
+            /*
+             * Internet format:
+             *  a.b.c.d
+             *  a.b.c   (with c treated as 16 bits)
+             *  a.b (with b treated as 24 bits)
+             */
+            if (pp >= parts + 3)
+                return (0);
+            *pp++ = val;
+            c = *++cp;
+        } else
+            break;
+    }
+    /*
+     * Check for trailing characters.
+     */
+    if (c != '\0' && (!isascii(c) || !isspace(c)))
+        return (0);
+    /*
+     * Concoct the address according to
+     * the number of parts specified.
+     */
+    n = pp - parts + 1;
+    switch (n) {
+
+    case 0:
+        return (0);     /* initial nondigit */
+
+    case 1:             /* a -- 32 bits */
+        break;
+
+    case 2:             /* a.b -- 8.24 bits */
+        if (val > 0xffffff)
+            return (0);
+        val |= parts[0] << 24;
+        break;
+
+    case 3:             /* a.b.c -- 8.8.16 bits */
+        if (val > 0xffff)
+            return (0);
+        val |= (parts[0] << 24) | (parts[1] << 16);
+        break;
+
+    case 4:             /* a.b.c.d -- 8.8.8.8 bits */
+        if (val > 0xff)
+            return (0);
+        val |= (parts[0] << 24) | (parts[1] << 16) | (parts[2] << 8);
+        break;
+    }
+    if (addr)
+        addr->s_addr = htonl(val);
+    return (1);
+}
+
+u32_t inet_addr(const char *cp)
+{
+    struct in_addr val;
+
+    if (inet_aton(cp, &val)) {
+        return (val.s_addr);
+    }
+
+    return INADDR_NONE;
+}
+