need help with this small code... pls..

SuperGirl · 08-18-2002

Hi there, first of all, i want to make the "ip1" char, go 1 higher, and i don't know how to do that. (like from 127.0.0.1 to 127.0.0.2).

And second, i'd like to know how to use it in system(); (or something else that does the same). i've tried adding it to system, but i get this error,
error C2660: 'system' : function does not take 3 parameters

How can i do this, please help.... i've searched my ass off..... hehe

Code:

#include<iostream.h>
#include<process.h>

int main()
{
	char ip1[15];
	char ip2[15];

	cout << "Start IP: ";
	 cin >> ip1;

	cout << "Stop IP: ";
	 cin >> ip2;


	if (ip1<ip2)
	{
		cout << "Start IP can not be higher than Stop IP." << endl;
	}
	else
	{
		cout << "Scanning: [" << ip1 << "] -> [" << ip2 << "]" << endl;

		while(ip1!=ip2)
		{
			/* Here i want to add the "ip1" char to system(); */

			/* Here i want the "ip1" char to go 1 higher. */
		}
	}

	cin.get();
	
	return 0;
}

**SilentStrike** · 08-19-2002

Code:

if (ip1<ip2)

That isn't doing what you want it to do. It's not comparing them lexigraphically (IE, 'a' < 'b' < 'c'), but rather simply comparing the addresses.

It would be easiest to store the ips as 4 chars (think of them as bytes rather than letters, one for each octet in the IP), and then convert them to the human readable ip format

Code:

#include <iostream>
#include <cstdlib>
#include <sstream>

int main() {
	unsigned char ip[4];
	unsigned char upperLim;
	int tempInt;  // read stuff as integers rather than characters

	std::cout << "Enter space delimited IP, ie, 192 168 1 1\n";
	for (int i = 0; i < 4; ++i) {
		std::cin >> tempInt;
		ip[i] = (unsigned char) tempInt;
	}

	std::cout << "Enter upper limit (inclusive, last octet only): ";
	std::cin >> tempInt;
	upperLim = (unsigned char) tempInt;

	do {
		std::ostringstream out; // use ostringstream to write the bytes into a string
		for (int i = 0; i < 3; ++i) { // write out first 3 with a ,
			out << (int) ip[i] << '.';
		}
		out << (int) ip[3];
		std::cout << out.str() << '\n';
// unixesque ping args, dunno if windows supports the -c option to ping or output redirection
		std::string command_line_arg = "ping -c 1 " + out.str(); // + ">"  +out.str() + ".result";
		system(command_line_arg.c_str());
		ip[3]++;
	} while  (ip[3] < upperLim);

	return 0;
}

I sense some malicous use of this code... don't try to destroy stuff with it please.

**Eibro** · 08-19-2002

Before calling system() you'll need to combine the strings/integers/other stuff using sprintf();

Example:

char ip1[] = "127.0.0.1";
char pszBuffer[32];

sprintf(pszBuffer, "ping %s", ip1);
// pszBuffer now contains "ping 127.0.0.1;

Now, to increment the IP is going to be a little tricky. You could make your own structure / class for IP's which would encapsulate all this... but here goes.

Code:

char *incrementIP(char *pszIP)
{
	char cDelim = '.';
	unsigned int iIPField[4];

	int i = 0;
	do {

		iIPField[i] = atoi(strtok(NULL, cDelim));
		i++;

	} while (i < 4);
	i = 4;

	while (iIPField[i] == 255)
	{
		iIPField[i] = 0;
		i--;
	} else {
		iIPField[i]++;
	}

	char pszReturnIP[16];
	sprintf(pszReturnIP, "%s.%s.%s.%s", iIPField[0], iIPField[1], iIPField[2], iIPField[3]);

	return pszReturnIP;
}

Note, I didn't test this... it's almost 3AM, I have no clue why I just wrote that for you but I did... the function doesn't check for validity of the IP address... it assumes a real address is given (4 fields seperated by periods.

SuperGirl · 08-19-2002

wow, thx guys....... don't worry i'm not gonna 'destroy' anything.

**moi** · 08-19-2002

Originally posted by SuperGirl
wow, thx guys....... don't worry i'm not gonna 'destroy' anything.

i'm listening; what non-malicious use do you have for this code?

**Hammer** · 08-19-2002

Another approach:

Code:

#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

using namespace std;

int main(void)
{
    struct in_addr addr;
    unsigned long host_order;
    
    addr.s_addr = inet_addr("127.0.0.1");
    host_order = ntohl(addr.s_addr);
    
    for (int i = 0; i < 10; i++)
    {
        cout <<inet_ntoa(addr) <<endl;
        addr.s_addr = htonl(++host_order);
    }
    
	return 0;
}

The IP address is stored as a long, as returned from inet_addr(), but it's in network byte order. So, using ntohl(), convert it to host order in order to store a copy. Then increment the copy and update the network ordered version when you want to use it.

This code ain't bullet proof, and requires Unix style sockets. But it can be adapted for Winsock use if that's what you want.

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