了解结构 sockaddr [英] Understanding struct sockaddr

问题描述

struct sockaddr {
    unsigned short sa_family;   // address family, AF_xxx
    char           sa_data[14]; // 14 bytes of protocol address
};

在这个结构中，sa_family所描述的address family究竟是什么意思?

In this structure what exactly is the meaning address family depicted by sa_family?

这是否意味着像 TCP/UDP 这样的协议有地址"?好吧，我认为协议可以是识别号而不是地址.

Does it mean that protocols like TCP/UDP have "addresses"? Well, the protocols can be identification numbers not addresses, I think.

无论如何，如果是，那么他们的家庭是根据什么划分的?

Anyway, if yes, then on what basis have their families been divided?

推荐答案

地址的格式和大小通常是特定于协议的.

The format and size of the address is usually protocol specific.

sockaddr 用作一组地址结构的基础，这些地址结构的作用类似于可区分的联合，请参阅 Beej 网络指南.你一般看sa_family，然后转换成合适的地址族的具体地址结构.

sockaddr is used as the base of a set of address structures that act like a discriminated union, see the Beej guide to networking. You generally look at the sa_family and then cast to the appropriate address family's specific address structure.

TCP 和 UDP 本身并没有特定的地址，而是 IP 级别对于 IPv4 和 IPv6 有不同大小的地址.

TCP and UDP do not have addresses specific to them as such, rather the IP level has different sizes of address for IPv4 and IPv6.

另见:

• http://en.wikipedia.org/wiki/AF_INET
• http://msdn.microsoft.com/en-us/library/ms740496(v=vs.85).aspx
• http://www.iana.org/assignments/address-family-numbers/address-family-numbers.xml

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