1 /*
2  * getaddrinfo(3) (name->address lookup) tester.
3  *
4  * Compile with:
5  *
6  * cc -o getaddrinfo getaddrinfo.c (BSD, Linux)
7  *
8  * cc -o getaddrinfo getaddrinfo.c -lsocket -lnsl (SunOS 5.x)
9  *
10  * Run as: getaddrinfo hostname
11  *
12  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
13  *
14  * Author: Wietse Venema, IBM T.J. Watson Research, USA.
15  */
16#include <sys/types.h>
17#include <sys/socket.h>
18#include <netinet/in.h>
19#include <arpa/inet.h>
20#include <netdb.h>
21#include <stdio.h>
22#include <unistd.h>
23#include <string.h>
24#include <stdlib.h>
25
26int     main(int argc, char **argv)
27{
28    char    hostbuf[NI_MAXHOST];	/* XXX */
29    struct addrinfo hints;
30    struct addrinfo *res0;
31    struct addrinfo *res;
32    const char *addr;
33    int     err;
34
35#define NO_SERVICE ((char *) 0)
36
37    if (argc != 2) {
38	fprintf(stderr, "usage: %s hostname\n", argv[0]);
39	exit(1);
40    }
41    memset((char *) &hints, 0, sizeof(hints));
42    hints.ai_family = PF_UNSPEC;
43    hints.ai_flags = AI_CANONNAME;
44    hints.ai_socktype = SOCK_STREAM;
45    if ((err = getaddrinfo(argv[1], NO_SERVICE, &hints, &res0)) != 0) {
46	fprintf(stderr, "host %s not found: %s\n", argv[1], gai_strerror(err));
47	exit(1);
48    }
49    printf("Hostname:\t%s\n", res0->ai_canonname);
50    printf("Addresses:\t");
51    for (res = res0; res != 0; res = res->ai_next) {
52	addr = (res->ai_family == AF_INET ?
53		(char *) &((struct sockaddr_in *) res->ai_addr)->sin_addr :
54		(char *) &((struct sockaddr_in6 *) res->ai_addr)->sin6_addr);
55	if (inet_ntop(res->ai_family, addr, hostbuf, sizeof(hostbuf)) == 0) {
56	    perror("inet_ntop:");
57	    exit(1);
58	}
59	printf("%s ", hostbuf);
60    }
61    printf("\n");
62    freeaddrinfo(res0);
63    exit(0);
64}
65