Files
getifaddr/src/getifaddr.c
2025-06-21 15:37:10 +01:00

54 lines
1.4 KiB
C

#define _GNU_SOURCE /* To get defns of NI_MAXSERV and NI_MAXHOST */
#include <ifaddrs.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/if_link.h>
#include <string.h>
char * get_if_addr(char *ifname)
{
struct ifaddrs * list, * plist;
int family, s;
char host[NI_MAXHOST];
char *result;
if (getifaddrs (&list)==-1)
{
fprintf(stderr, "no info");
return NULL;
}
plist = list;
while (plist!=NULL)
{
if (strcmp(plist->ifa_name,ifname)==0)
{
family = plist->ifa_addr->sa_family;
if (family == AF_INET || family == AF_INET6) {
s = getnameinfo(plist->ifa_addr,
(family == AF_INET) ? sizeof(struct sockaddr_in) :
sizeof(struct sockaddr_in6),
host, NI_MAXHOST,
NULL, 0, NI_NUMERICHOST);
if (s != 0) {
fprintf(stderr, "getnameinfo() failed: %s\n", gai_strerror(s));
exit(EXIT_FAILURE);
}
result = malloc(strlen(host)+1);
strcpy(result,host);
freeifaddrs (list);
return result;
}
}
plist = plist->ifa_next;
}
freeifaddrs (list);
return NULL;
}