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/*
* getnameinfo(3) (address->name lookup) tester.
*
* Compile with:
*
* cc -o getnameinfo getnameinfo.c (BSD, Linux)
*
* cc -o getnameinfo getnameinfo.c -lsocket -lnsl (SunOS 5.x)
*
* Run as: getnameinfo address
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*
* Author: Wietse Venema, IBM T.J. Watson Research, USA.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
char hostbuf[NI_MAXHOST]; /* XXX */
struct addrinfo hints;
struct addrinfo *res0;
struct addrinfo *res;
const char *host;
const char *addr;
int err;
#define NO_SERVICE ((char *) 0)
if (argc != 2) {
fprintf(stderr, "usage: %s ipaddres\n", argv[0]);
exit(1);
}
/*
* Convert address to internal form.
*/
host = argv[1];
memset((char *) &hints, 0, sizeof(hints));
hints.ai_family = (strchr(host, ':') ? AF_INET6 : AF_INET);
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags |= AI_NUMERICHOST;
if ((err = getaddrinfo(host, NO_SERVICE, &hints, &res0)) != 0) {
fprintf(stderr, "getaddrinfo %s: %s\n", host, gai_strerror(err));
exit(1);
}
/*
* Convert host address to name.
*/
for (res = res0; res != 0; res = res->ai_next) {
err = getnameinfo(res->ai_addr, res->ai_addrlen,
hostbuf, sizeof(hostbuf),
NO_SERVICE, 0, NI_NAMEREQD);
if (err) {
fprintf(stderr, "getnameinfo %s: %s\n", host, gai_strerror(err));
exit(1);
}
printf("Hostname:\t%s\n", hostbuf);
addr = (res->ai_family == AF_INET ?
(char *) &((struct sockaddr_in *) res->ai_addr)->sin_addr :
(char *) &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr);
if (inet_ntop(res->ai_family, addr, hostbuf, sizeof(hostbuf)) == 0) {
perror("inet_ntop:");
exit(1);
}
printf("Address:\t%s\n", hostbuf);
}
freeaddrinfo(res0);
exit(0);
}
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