Question

printf(" Dst Address:\n");
for(i = 0;i < 4;i++)
printf(" %d ",((ip->ip_dst.s_addr)&(0x0FF<<(i*8)))>>(i*8));

by this i am able to print the destination ip address as 192.28.2.11 but i want just want the first two numbers 192 and 28 how can i get this two value.?

Answer 1

What’s wrong with just modifying the code you have:

int a[4];
for (i = 0; i < 4; i++)
    a[i] = ((ip->ip_dst.s_addr)&(0x0FF<<(i*8)))>>(i*8);

That should give them to you in a[0] and a[1].

---

The following code shows one way to do it. The IP address is reversed (0x0b0280c0) due to the x86 little-endian format:

#include <stdio.h>
int main (void) {
    int i;
    unsigned int addr = 0x0b0280c0;
    int a[4];
    for (i = 0; i < 4; i++)
        a[i] = ((addr)&(0x0FF<<(i*8)))>>(i*8);
    printf ("%d %d %d %d\n", a[0], a[1], a[2], a[3]);
    return 0;
}

It outputs:

192 128 2 11

and you can see that the components are placed in the individual array elements.