/*====================================================================
   UDP SCAN Ver1.00 
   The Shadow Penguin Security (http://shadowpenguin.backsection.net)
   Written by UNYUN (unewn4th@usa.net)
  ====================================================================
*/

#include    <stdio.h>
#include    <sys/socket.h>
#include    <netinet/ip_icmp.h>

#define SRC_PORT    10101

int main(int argc, char *argv[])
{
    struct icmphdr     *icmp_header;
    struct sockaddr_in target_info;
    int                target_info_len;
    fd_set             read_fd;
    int                scan_port;
    char               recvbuf[5000];
    struct sockaddr_in target_addr;
    int                icmp_socket;
    int                udp_socket;

    if (argc!=3){
        printf("[usage] %s [TargetIP] [TargetPort] \n",argv[0]);
        return -1;
    }
    icmp_header  = (struct icmphdr *)(recvbuf+sizeof(struct iphdr));
    scan_port    = atoi(argv[2]);
    target_addr.sin_family         = AF_INET;
    target_addr.sin_addr.s_addr    = inet_addr(argv[1]);
    target_addr.sin_port           = htons(scan_port);

    if ((udp_socket=socket(AF_INET,SOCK_DGRAM,0))==-1){
        printf("UDP Socket Creation Error.\n");
        return -1;
    }
    if ((icmp_socket=socket(AF_INET,SOCK_RAW,IPPROTO_ICMP))==-1){
        printf("RAW Socket Creation Error.\n");
        return -1;
    }

    sendto(udp_socket,NULL,0,0,(void *)&target_addr,sizeof(target_addr));
    FD_ZERO(&read_fd);
    FD_SET(icmp_socket,&read_fd);
    select(FD_SETSIZE,&read_fd,NULL,NULL,NULL);
    for (;;){
        if (FD_ISSET(icmp_socket,&read_fd)){
            target_info_len = sizeof(target_info);
            recvfrom(icmp_socket,recvbuf,5000,0,
                     (struct sockaddr *)&target_info,&target_info_len);
            if (target_info.sin_addr.s_addr == target_addr.sin_addr.s_addr
             && icmp_header->type == 3  && icmp_header->code<=12){
                     printf("Port %d : Close\n",scan_port);
                     exit(1);
            }
       }
    }
    return(0);
}