Linux 扩展 IPv6 地址，以便我可以将其打印到标准输出
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expand an IPv6 address so I can print it to stdout
提问by Jessica
I am using getifaddrs() and inet_ntop() to get the ip addresses on the system. When the system is set to IPv6 the address returned is in the shortened version (using :: for zeros). Is there any way to expand that address to a full one?
我正在使用 getifaddrs() 和 inet_ntop() 来获取系统上的 IP 地址。当系统设置为 IPv6 时，返回的地址是缩短版本（使用 :: 表示零）。有没有办法将该地址扩展为完整地址？
This is the code I am using:
这是我正在使用的代码：
struct ifaddrs *myaddrs, *ifa;
void *in_addr;
char buf[64];
if(getifaddrs(&myaddrs) != 0)
{
perror("getifaddrs");
exit(1);
}
for (ifa = myaddrs; ifa != NULL; ifa = ifa->ifa_next)
{
if (ifa->ifa_addr == NULL)
continue;
if (!(ifa->ifa_flags & IFF_UP))
continue;
switch (ifa->ifa_addr->sa_family)
{
case AF_INET:
{
struct sockaddr_in *s4 = (struct sockaddr_in *)ifa->ifa_addr;
in_addr = &s4->sin_addr;
break;
}
case AF_INET6:
{
struct sockaddr_in6 *s6 = (struct sockaddr_in6 *)ifa->ifa_addr;
in_addr = &s6->sin6_addr;
break;
}
default:
continue;
}
if (!inet_ntop(ifa->ifa_addr->sa_family, in_addr, buf, sizeof(buf)))
{
printf("%s: inet_ntop failed!\n", ifa->ifa_name);
}
else
{
printf("IP address: %s\n", buf);
}
}
freeifaddrs(myaddrs);
Code is greatly appreciated.
非常感谢代码。
EDIT:
Since this is apparently very hard to comprehend I will give you an example:
编辑：
由于这显然很难理解，我会给你一个例子：
If I get abcd:12::3 I need to expand it to abcd:0012:0000:0000:0000:0000:0000:0003
The reason? because it's part of the requirements. Simple as that.
如果我得到 abcd:12::3 我需要将它扩展为 abcd:0012:0000:0000:0000:0000:0000:0003
原因？因为这是要求的一部分。就那么简单。
采纳答案by nategoose
void ipv6_to_str_unexpanded(char * str, const struct in6_addr * addr) {
sprintf(str, "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",
(int)addr->s6_addr[0], (int)addr->s6_addr[1],
(int)addr->s6_addr[2], (int)addr->s6_addr[3],
(int)addr->s6_addr[4], (int)addr->s6_addr[5],
(int)addr->s6_addr[6], (int)addr->s6_addr[7],
(int)addr->s6_addr[8], (int)addr->s6_addr[9],
(int)addr->s6_addr[10], (int)addr->s6_addr[11],
(int)addr->s6_addr[12], (int)addr->s6_addr[13],
(int)addr->s6_addr[14], (int)addr->s6_addr[15]);
}
回答by Arun Raj
#include<stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
struct in6_addrr
{
unsigned char addr[16];
};
void ipv6_expander(const struct in6_addr * addr)
{
char str[40];
sprintf(str,"%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",
(int)addr->s6_addr[0], (int)addr->s6_addr[1],
(int)addr->s6_addr[2], (int)addr->s6_addr[3],
(int)addr->s6_addr[4], (int)addr->s6_addr[5],
(int)addr->s6_addr[6], (int)addr->s6_addr[7],
(int)addr->s6_addr[8], (int)addr->s6_addr[9],
(int)addr->s6_addr[10], (int)addr->s6_addr[11],
(int)addr->s6_addr[12], (int)addr->s6_addr[13],
(int)addr->s6_addr[14], (int)addr->s6_addr[15]);
printf("\nExpanded ipv6 Addr %s\n",str);
}
int main(int argc,char *argv[])
{
struct in6_addrr ipv6;
printf("\nGiven IPv6 Addr %s\n",argv[1]);
if(inet_pton(AF_INET6,argv[1],&ipv6.addr))
{
ipv6_expander(&ipv6.addr);
}
else
{
printf("\n error\n");
}
return;
}
