1 #include <sys/types.h>

     2 #include <sys/socket.h>

     3 #include <netdb.h>

     4 #include <arpa/inet.h>

     5 

     6 #include <stdio.h>

     7 #include <stdlib.h>

     8 #include <string.h>

     9 

    10 int main(int argc, char **argv)

    11 {

    12     const char *node, *service, *proto;

    13     struct addrinfo *r, *results;

    14     struct addrinfo hints = { 0 };

    15     int e;

    16 

    17     if (argc < 2) {

    18 	fprintf(stderr, "Usage: %s hostname [service [protocol]]\n", argv[0]);

    19 	exit(1);

    20     }

    21 

    22     node = argc > 1 ? argv[1] : NULL;

    23     service = argc > 2 ? argv[2] : NULL;

    24     proto = argc > 3 ? argv[3] : NULL;

    25 

    26     hints.ai_socktype = proto == NULL ? 0

    27 	: strcmp(proto, "tcp") == 0 ? SOCK_STREAM

    28 	: strcmp(proto, "udp") == 0 ? SOCK_DGRAM

    29 	: 0;

    30 

    31     e = getaddrinfo(node, service, &hints, &results);

    32 

    33     if (e) {

    34 	fprintf(stderr, "%s: %s\n", argv[0], gai_strerror(e));

    35 	exit(3);

    36     }

    37 

    38 

    39     for (r = results; r != 0; r = r->ai_next) {

    40 	char host[1024];

    41 	char service[1024];

    42 	int e;

    43 	e = getnameinfo(r->ai_addr, r->ai_addrlen,

    44 	    host, sizeof(host),

    45 	    service, sizeof(service),

    46 	    NI_NUMERICHOST | NI_NUMERICSERV);

    47 

    48 	if (e) {

    49 	    fprintf(stderr, "getnameinfo: %s\n", gai_strerror(e));

    50 	    continue;

    51 	}

    52 

    53 	printf("%s, %s %d/%d\n", host, service, r->ai_socktype, r->ai_protocol);

    54     }

    55 

    56 

    57     return 0;

    58 

    59 }