udp套接字到底接收什么？

Question

  #include <sys/socket.h>
  #include <netinet/in.h>
  #include <netinet/udp.h>

  udp_socket = socket(AF_INET, SOCK_DGRAM, 0);

当我使用 UDP 套接字时，我是只接收负载还是接收 UDP header？

Answer 1

您可以访问或不能访问的内容取决于套接字的创建方式。

这是文档中与您的问题相关的评论：

The recv() function shall receive a message from a connection-mode or connectionless-mode socket. It is normally used with connected sockets because it does not permit the application to retrieve the source address of received data.

（强调我的）

read more here...

编辑：如果访问 header 信息是您想要做的，请阅读此内容和以下内容 link。

...You cannot create a raw socket with IPPROTO_UDP and manipulate the UDP header; likewise with TCP. To manipulate the IP header as well as either the TCP or UDP header (or any other protocol encapsulated in IP), you must use the IP_HDRINCL socket option with a raw socket. ...

阅读more on the topic...

udp套接字到底接收什么？

What exactly does a udp socket receive?

c

sockets

networking

udp