// reference: https://www.geekpage.jp/programming/winsock/getaddrinfo.php


#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

void dump(void *ptr, int len)
{
	int i;
	unsigned char *p = ptr;

	for (i = 0; i < len; i++) {
		if (i && !(i % 16)) printf("\t\t");
		printf("%02x ", *p++);
		if (!((i + 1) % 16)) printf("\n");
	}

	if (i % 16) printf("\n");
}

int main(int argc, char *argv[])
{
	struct addrinfo hints, *res, *rp;
	int err;

	if (argc < 2) {
		printf("%s [argument]\n", argv[0]);
		return 0;
	}

	memset(&hints, 0, sizeof(hints));
	hints.ai_socktype = SOCK_DGRAM;
	//hints.ai_family = AF_INET;
	//node is not NULL, so hints.ai_flags = AI_PASSIVE has no meaning
	hints.ai_flags = AI_CANONNAME;
	
	err = getaddrinfo(argv[1], NULL, &hints, &res);
	if (err) {
		printf("getaddrinfo %d\n", err);
		return 0;
	}

	for (rp = res; rp != NULL; rp = rp->ai_next) {
		printf("*\n");

		printf("ai_flags:	%#x\n", rp->ai_flags);
		printf("ai_family:	%#x\n", rp->ai_family);
		printf("ai_socktype:	%#x\n", rp->ai_socktype);
		printf("ai_addrlen:	%#x\n", rp->ai_addrlen);
		printf("ai_addr:	");
		dump(rp->ai_addr, rp->ai_addrlen);
		printf("ai_canonname:	%s\n", rp->ai_canonname);
	}

	freeaddrinfo(res);
	return 0;
}