accept执行后第二个参数可以看出来
addr
[out] Optional pointer to a buffer that receives the address of the connecting entity, as known to the communications layer. The exact format of the addr parameter is determined by the address family that was established when the socket was created
通常聊天工具应该都是通过中继服务器方式转发的,它给你传了,你才可以有可能获得的