C语言 如何从c中的sock结构获取IP地址？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3060950/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to get ip address from sock structure in c?
提问by REALFREE
I'm writing simple server/client and trying to get client IP address and save it on server side to decide which client should get into critical section. I googled it several times but couldn't find proper way to get IP address from sock structure.
我正在编写简单的服务器/客户端并尝试获取客户端 IP 地址并将其保存在服务器端以决定哪个客户端应该进入临界区。我用谷歌搜索了好几次，但找不到从袜子结构中获取 IP 地址的正确方法。
I believe this is a way to get IP from sock struct after server accept request from client. More specifically in c after server execute
我相信这是一种在服务器接受客户端请求后从 sock 结构中获取 IP 的方法。更具体地说，在服务器执行后的 c 中
csock = accept(ssock, (struct sockaddr *)&client_addr, &clen)
Thanks
谢谢
回答by Goz
OK assuming you are using IPV4 then do the following:
好的，假设您使用的是 IPV4，然后执行以下操作：
struct sockaddr_in* pV4Addr = (struct sockaddr_in*)&client_addr;
struct in_addr ipAddr = pV4Addr->sin_addr;
If you then want the ip address as a string then do the following:
如果您希望将 IP 地址作为字符串，请执行以下操作：
char str[INET_ADDRSTRLEN];
inet_ntop( AF_INET, &ipAddr, str, INET_ADDRSTRLEN );
IPV6 is pretty easy as well ...
IPV6也很容易...
struct sockaddr_in6* pV6Addr = (struct sockaddr_in6*)&client_addr;
struct in6_addr ipAddr = pV6Addr->sin6_addr;
and getting a string is almost identical to IPV4
并且获取字符串几乎与 IPV4 相同
char str[INET6_ADDRSTRLEN];
inet_ntop( AF_INET6, &ipAddr, str, INET6_ADDRSTRLEN );
回答by Misha
The easier and correct way for extracting IP address and port number would be:
提取 IP 地址和端口号的更简单和正确的方法是：
printf("IP address is: %s\n", inet_ntoa(client_addr.sin_addr));
printf("port is: %d\n", (int) ntohs(client_addr.sin_port));
The SoapBox's accepted answer won't be correct for all architectures. See Big and Little Endian.
SoapBox 接受的答案并不适用于所有架构。请参阅大端和小端。
回答by SoapBox
Assuming client_addris a struct sockaddr_in(which it usually is). You can get the IP address (as a 32-bit unsigned integer) from client_addr.sin_addr.s_addr.
假设client_addr是一个struct sockaddr_in（通常是）。您可以从client_addr.sin_addr.s_addr.
You can convert it to a string this way:
您可以通过以下方式将其转换为字符串：
printf("%d.%d.%d.%d\n",
int(client.sin_addr.s_addr&0xFF),
int((client.sin_addr.s_addr&0xFF00)>>8),
int((client.sin_addr.s_addr&0xFF0000)>>16),
int((client.sin_addr.s_addr&0xFF000000)>>24));
