Random IP Generation Program

Hello,I was Designing a Program that has two function the random_ip() and main()
the random_ip() returns an array of random generated ip address

Code:

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#include<stdio.h>
#include<netinet/in.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<errno.h>

char* random_ip(char figure,int size,int check)//a thousand,mil,bil etc
{
        printf("Figure %c Size %d\n",figure,size);
        int i=65536;       
        int j=0;
        int  BUFSIZE;
        struct sockaddr_in temp;
        switch(figure)
        {
                case 't':
                BUFSIZE=(size*1024);
                break;

                case 'm':
                BUFSIZE=(size*1024*1024);
                break;
       
                case 'b':
                BUFSIZE=(size*1024*1024*1024);
                break;

                default:printf("Choose btn choices available!\n");
        }       
        printf("BUFSIZE %d\n",BUFSIZE);
        char *ip_buffer[BUFSIZE];
        srand(i);//seed the randomizer
        while(j<BUFSIZE)
        {
                ip_buffer[j]=(char*)malloc(16);
                temp.sin_addr.s_addr=(unsigned long)rand()%4294967295;

                ip_buffer[j]=(char*)malloc(16);

                strcpy(ip_buffer[j],inet_ntoa(temp.sin_addr));
               
                j++;
       
        }
       
        if(check){
        int a;
        int repeated=0;
        char*ip;
        for(j=0;j<BUFSIZE;j++)
        {
                ip=(char*)malloc(16);
                strcpy(ip,ip_buffer[j]);
               
                for(a=++j;a<BUFSIZE;a++)
                {       
                        if((strcmp(ip,ip_buffer[a]))==0){//repeated ip       
                                repeated++;       
                                printf("\t\t\t\tFound %s repeated addresses.\n",ip);
                        }       
                }       
                ip=NULL;
        }
        if(repeated>0)
        printf("Found %d repetead Addresses in %d Addresses.\n",repeated,BUFSIZE);
        }
       
return ip_buffer;
}
main(int argc,char**argv)
{

        int i=9;
        int j=0;
        int BUFSIZE;
        srand(i);//seed the randomizer
        switch((char)*argv[1])
        {
                case 't':
                BUFSIZE=(atoi(argv[2])*1024);
                break;

                case 'm':
                BUFSIZE=(atoi(argv[2])*1024*1024);
                break;
       
                case 'b':
                BUFSIZE=(atoi(argv[2])*1024*1024*1024);
                break;

                default:printf("Choose btn choices available!\n");
        }
        printf("BUFSIZE MAIN:%d\n",BUFSIZE);
        char *ip_buffer[BUFSIZE];
        memcpy(ip_buffer,random_ip((char)*argv[1],atoi(argv[2]),0),BUFSIZE);
       
        while(j<BUFSIZE)
        {
        printf("%s\t\t\t %d\n",ip_buffer[j],j);
        //printf("%s\n",inet_addr((char*)ip_buffer[j]));
        j++;
       
        }printf("%d Addresses\n",j);
       
}

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it seems the code has a problem with the memcpy() function.Please Help figure this one out!
Thanks.

Care to share what the compiler error was exactly?

Why not save everyone a lot of time?

I have received compiler warnings that looks like

Code:

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random_ip.c: In function ‘random_ip’:
random_ip.c:51: warning: this decimal constant is unsigned only in ISO C90
random_ip.c:83: warning: return from incompatible pointer type
random_ip.c:83: warning: function returns address of local variable

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It has a 'Segmentation fault' Error At Runtime...

Did you do the math to figure out A) how big an IP address is and B) how big your buffers are?

Code:

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char *ip_buffer[BUFSIZE];

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Do you really expect to create a multi gigabyte (argv[2]*1024*1024*1024) array on the program's stack?

argv[2] is a pointer, you're treating it like a number, probably at least 5 digits... so lets assume conservativley it comes up with 10001...
How big is that array going to be?

10001 *1024 *1024 *1024 = 10,738,491,981,824

Got ram?

Thanks Tater!I tried once with 1024*1024 array size it work but too slow.


What size a program's stack is?It might be are reason why memcpy() fails

Quote:

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Originally Posted by lvandaz

Thanks Tater!I tried once with 1024*1024 array size it work but too slow.


What size a program's stack is?It might be are reason why memcpy() fails

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Probably about a tenth of a percent of what you're asking for... typically a megabyte.

Look, I don't know exactly what you're trying to do (although it looks suspiciously like a DOS Bomb) but you're going to have to figure out a way to do it without asking your system for (potentially) 10 terrabytes of ram.

STOP ... Explain your intentions immediately!

Anyone giving any advice here should think, would they be happy if this program, or whatever it evolved into or is really part of, happened to randomly generate your IP address? I mean what do any of you think is going to happen next?
The only possible thing I can think of for generating random IP Addresses is that this person is atempting to write a virus/worm etc.

You've got some major problems anyway:

Code:

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char* random_ip(...) /* return a pointer to char */
{
        ....
        char *ip_buffer[BUFSIZE]; /* make an array of pointers to characters ... local to this function */
        ....
return ip_buffer; /* oops */
}

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Or you could just you know:

Code:

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printf( "%d.%d.%d.%d", rand()&0xFF,rand()&0xFF,rand()&0xFF,rand()&0xFF );

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Quzah.

Thanks!I think I figure out some other solns for my "problem" :-)

Quote:

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Originally Posted by lvandaz

Thanks!I think I figure out some other solns for my "problem" :-)

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Ummm.... what is a "soln" ?