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/*
* Based on code found at https://dev.openwrt.org/ticket/4876 .
* Extended by Jo-Philipp Wich <jow@openwrt.org> for use in OpenWrt.
*
* You may use this program under the terms of the GPLv2 license.
*/
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
static void abort_query(int sig)
{
exit(1);
}
static void show_usage(void)
{
printf("Usage:\n");
printf(" resolveip -h\n");
printf(" resolveip [-t timeout] hostname\n");
printf(" resolveip -4 [-t timeout] hostname\n");
printf(" resolveip -6 [-t timeout] hostname\n");
exit(255);
}
int main(int argc, char **argv)
{
int timeout = 3;
int opt;
char ipaddr[INET6_ADDRSTRLEN];
void *addr;
struct addrinfo *res, *rp;
struct sigaction sa = { .sa_handler = &abort_query };
struct addrinfo hints = {
.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_protocol = IPPROTO_TCP,
.ai_flags = 0
};
while ((opt = getopt(argc, argv, "46t:h")) > -1)
{
switch ((char)opt)
{
case '4':
hints.ai_family = AF_INET;
break;
case '6':
hints.ai_family = AF_INET6;
break;
case 't':
timeout = atoi(optarg);
if (timeout <= 0)
show_usage();
break;
case 'h':
show_usage();
break;
}
}
if (!argv[optind])
show_usage();
sigaction(SIGALRM, &sa, NULL);
alarm(timeout);
if (getaddrinfo(argv[optind], NULL, &hints, &res))
exit(2);
for (rp = res; rp != NULL; rp = rp->ai_next)
{
addr = (rp->ai_family == AF_INET)
? (void *)&((struct sockaddr_in *)rp->ai_addr)->sin_addr
: (void *)&((struct sockaddr_in6 *)rp->ai_addr)->sin6_addr
;
if (!inet_ntop(rp->ai_family, addr, ipaddr, INET6_ADDRSTRLEN - 1))
exit(3);
printf("%s\n", ipaddr);
}
freeaddrinfo(res);
exit(0);
}
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