port scanner

gistfile1.txt

#include <string>
#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sstream>
#include <netdb.h>
#include <iostream>
#include <sstream>
#include <string>
#include <cstdio>
#include <vector>

using namespace std;
int current_port = 0;
void scan_open_ports(string hostname, vector<int>* ret_val)
{
  
  
  int _socket = socket(AF_INET, SOCK_STREAM, 0);
  if(_socket < 0) { cout << "Error opening socket..." << endl; return;}
  
  struct hostent *target_server = gethostbyname(hostname.c_str());
  struct sockaddr_in target_address;
  
  if(target_server == NULL) { cout << "Error no such host exists" << endl; return;};
  
  bzero((char*)&target_address, sizeof(target_address));
  target_address.sin_family = AF_INET;
  bcopy((char*)target_server->h_addr, (char*) &target_address.sin_addr.s_addr,target_server->h_length);
  
  target_address.sin_port = htons(current_port);
  
  if(connect(_socket, (struct sockaddr*) &target_address,sizeof(target_address)) < 0)
  {
    //something went wrong...
    close(_socket);
    cout << "Cannot connect to " << hostname << " on port " << current_port << endl;
    ++current_port;
    scan_open_ports(hostname, ret_val);
  }
  
  cout << "Established connection on port " << current_port << endl;
  ret_val->push_back(current_port);
  ++current_port;
  close(_socket);
  scan_open_ports(hostname,ret_val);
}
vector<int>* scan_ports(string input)
{
    vector<int>* ret_val = new vector<int>();
    
    scan_open_ports(input, ret_val);
    
}
int main(int argc, char **argv) {
    
    scan_ports("172.20.141.10");
    return 0;
}