at_device在下载大文件时出现数据错误的bug

我使用AT_device通过http从网站上下载大文件时，发现每次数据都不正常，数据中总是夹杂着大量无用的数据，通过查找，发现rt-thread/components/net/at/at_socket/at_socket.c这个文件中的
static size_t at_recvpkt_get(rt_slist_t *rlist, char *mem, size_t len)
中链表使用应该是存在问题的，修改后的代码如下：
static size_t at_recvpkt_get(rt_slist_t *rlist, char *mem, size_t len)
{
rt_slist_t *node = RT_NULL;
at_recv_pkt_t pkt = RT_NULL;
size_t content_pos = 0, page_pos = 0;

if (rt_slist_isempty(rlist))
{
return 0;
}

for (node = rt_slist_first(rlist); node; )
{
pkt = rt_slist_entry(node, struct at_recv_pkt, list);

page_pos = pkt->bfsz_totle - pkt->bfsz_index;

//rt_kprintf("at_recvpkt_get3:%d %d\n",pkt->bfsz_totle,pkt->bfsz_index);

if (page_pos >= len - content_pos)
{
    memcpy((char *) mem + content_pos, pkt->buff + pkt->bfsz_index, len - content_pos);
    pkt->bfsz_index += len - content_pos;
    if (pkt->bfsz_index == pkt->bfsz_totle)
    {
        at_recvpkt_node_delete(rlist, node);
    }

    content_pos = len - content_pos;
    break;
}
else
{
    memcpy((char *) mem + content_pos, pkt->buff + pkt->bfsz_index, page_pos);
    content_pos += page_pos;

    pkt->bfsz_index += page_pos;
    rt_slist_t *tmpnode = rt_slist_next(node);
    at_recvpkt_node_delete(rlist, node);
    node = tmpnode;
    //node = rt_slist_next(node);
}

}
static int at_recvpkt_all_delete(rt_slist_t *rlist)
这个函数同样有问题，在关闭socket时，清理接收消息列表时会报异常，导致系统中断，修改如下：
static int at_recvpkt_all_delete(rt_slist_t *rlist)
{
at_recv_pkt_t pkt = RT_NULL;
rt_slist_t *node = RT_NULL;

//rt_kprintf("at_recvpkt_all_delete1.\n");

if (rt_slist_isempty(rlist))
{
return 0;
}

rt_kprintf("at_recvpkt_all_delete2.\n");

for(node = rt_slist_first(rlist); node; )
{
rt_slist_t *tmpnode = rt_slist_next(node);
at_recvpkt_node_delete(rlist,node);
node = tmpnode;
}

//rt_kprintf("at_recvpkt_all_delete3.\n");

return 0;
}
通过测试，现在下载数据一切正常。