Thread: Use of htons() and ntohs()

How can i use these functions to convert nertwork data to host data? (im sure that was poorly worded but im fairly new to this). I have a captured ICMP packet and have read from the file into a buffer and then populated a structure representing ethernet, ip packet and icmp structures.

I think i need to use the above ntohs and nothl functions on some of the data to make sense of it. I am just assuming this because if i were to use the program backwards to craft a packet, i would need to use honts and hontl on things like the packet identification and packet length.

So how could i use this on data already stored in a structure.

Any pointers or example code would be very much appreciated.

Cheers

Andy

htons - Windows Sockets

xeddiex.

I had a look at the MSDN example of u_short ntohs(...etc), but i dont see how i can use that in my situation. I reckon im being dense.

printf(" type length is %x\n", ethernet.typelength);

i need to use ntohs on that structure element, can i use it in the printf statement somehow? Or is there a way of setting a condition on the structure element itself so that when data is entered into it the function is automatically used. Maybe something along the lines of:

<code>

struct ip_struct
{
unsigned int ver:4;
unsigned int ihl:4;
unsigned char tos:8; unsigned int ntohs(length):16;
unsigned int ntohs(identification):16;
</code>

I know that is far from correct but im a man clutching at straws!