linux c语言 获取ip

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <linux/if_link.h>

void get_ip_addresses() {
    struct ifaddrs *ifaddr, *ifa;
    int family, s;

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

    for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
        if (ifa->ifa_addr == NULL)
            continue;

        family = ifa->ifa_addr->sa_family;

        if (family == AF_INET || family == AF_INET6) {
            s = getnameinfo(ifa->ifa_addr,
                            (family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6),
                            ifa->ifa_name, NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
            if (s != 0) {
                printf("getnameinfo() failed: %s
", gai_strerror(s));
                continue;
            }

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

    freeifaddrs(ifaddr);
}

int main() {
    get_ip_addresses();
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <arpa/inet.h>
#include <sys/ioctl.h>

void get_ip_addresses() {
    int sockfd;
    struct ifconf ifc;
    char buf[1024];
    int success = 0;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    ifc.ifc_len = sizeof(buf);
    ifc.ifc_buf = buf;
    if (ioctl(sockfd, SIOCGIFCONF, &ifc) == -1) {
        perror("ioctl(SIOCGIFCONF)");
        exit(EXIT_FAILURE);
    }

    struct ifreq *it = ifc.ifc_req;
    const struct ifreq *const end = it + (ifc.ifc_len / sizeof(struct ifreq));

    for (; it != end; ++it) {
        char hostname[NI_MAXHOST];
        if (getnameinfo(it->ifr_addr,
                        sizeof(struct sockaddr_in),
                        hostname, NI_MAXHOST,
                        NULL, 0, NI_NUMERICHOST) == 0) {
            printf("%s: %s
", it->ifr_name, hostname);
        }
    }

    close(sockfd);
}

int main() {
    get_ip_addresses();
    return 0;
}