네트워크프로그래밍 - 상대방의 접속정보를 알아내는 프로그램

#include <netdb.h>

#include <sys/socket.h>

#include <stdio.h>

int main(){

struct in_addr addr;

struct hostent *host;

const char *hostName;

int i;

printf("input url : ");

hostName = (char *)malloc(sizeof(char));          // 동적메모리 할당

scanf("%s",hostName);                                 //문자열을 받음

if((host = gethostbyname(hostName)) == NULL){

printf("gethostbyname() error - check network\n");

exit(-1);

}

printf("official name = %s\n", host->h_name);

i = 0;

while(host->h_aliases[i] != NULL){

printf("aliases = %s\n", host->h_aliases[i++]);

}

printf("address type = %d\n", host->h_addrtype);

printf("address length = %d\n", host->h_length);

i = 0;

while(host->h_addr_list[i] != NULL){

memcpy(&addr.s_addr, host->h_addr_list[i], 4);

printf("address = %s(0x%x)\n", inet_ntoa(addr), ntohl(*(long*)host->h_addr_list[i]));

i++;

}

return 0;

}