linuxcrtnetlinkRTM_GETADDR忽略ifaddrmsg结构中的ifa_index，并输出所有接口相关信息

使用getifaddrs()函数和ifaddrs结构体获取每个接口的相关信息，并通过筛选ifa_addr->sa_family == AF_INET6或AF_INET获取IPv6或IPv4地址。代码示例如下：

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <ifaddrs.h> #include <netdb.h> #include <netinet/in.h> #include <arpa/inet.h>

int main() { struct ifaddrs *ifaddr, *ifa; int family, s, n; char host[NI_MAXHOST];

if (getifaddrs(&ifaddr) == -1) {
    perror("getifaddrs");
    exit(EXIT_FAILURE);
}

// 遍历链表
for (ifa = ifaddr, n = 0; ifa != NULL; ifa = ifa->ifa_next, n++) {
    if (ifa->ifa_addr == NULL)
        continue;

    family = ifa->ifa_addr->sa_family;

    // 仅保留IPv6和IPv4地址
    if (family == AF_INET || family == AF_INET6) {
        s = getnameinfo(ifa->ifa_addr, (family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6), host, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
        if (s != 0) {
            printf("getnameinfo() failed: %s\n", gai_strerror(s));
            exit(EXIT_FAILURE);
        }

        printf("%s: %s\n", ifa->ifa_name, host);
    }
}

freeifaddrs(ifaddr);
exit(EXIT_SUCCESS);

}