From 350947b190aeda54ca002e88c87373f2d43e6244 Mon Sep 17 00:00:00 2001
From: senduo <645958643@qq.com>
Date: Fri, 26 Jul 2019 18:33:33 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E6=94=B9at=5Fsocket.c=E6=96=87?=
 =?UTF-8?q?=E4=BB=B6=E4=B8=AD=E7=9A=84sendto=E5=87=BD=E6=95=B0=EF=BC=8Clen?=
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len值如果不给初始值0，到最后__exit的时候，result = len会导致result的值变成一个不可预估的值，进而导致mbedtls库的while循环无法正常结束，其中mebedtls中发生异常的地方在ssl_tls.c文件中的mbedtls_ssl_flush_output函数while( ssl->out_left > 0 )，因为out_left 是一个无符号整型，退出的条件只能是 out_left = 0,又因为这里面的len没有给初始值0，返回出来的值是一个很大的整型数字，导致了mbedtls中的死循环
---
 components/net/at/at_socket/at_socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/components/net/at/at_socket/at_socket.c b/components/net/at/at_socket/at_socket.c
index 804443fe32..72ff9a7aa3 100644
--- a/components/net/at/at_socket/at_socket.c
+++ b/components/net/at/at_socket/at_socket.c
@@ -856,7 +856,7 @@ int at_recv(int s, void *mem, size_t len, int flags)
 int at_sendto(int socket, const void *data, size_t size, int flags, const struct sockaddr *to, socklen_t tolen)
 {
     struct at_socket *sock = RT_NULL;
-    int len, result = 0;
+    int len = 0, result = 0;
 
     if (data == RT_NULL || size == 0)
     {