[Olsr-users] olsr.org olsrd and nrlsmf

[Bernd Petrovitsch]

On Die, 2008-08-19 at 09:18 +0200, Roar Bjørgum Rotvik wrote:
[...]
> Or just use ioctl(), here is a short example:

Cute. But where does this actually work?
Because my recent Linux kernels needs the device name too as added below
(yes, one wants to make it a parameter of the function).
Otherwise I get a "No such device".

> Input is IPv4 address (ip argument), returned MAC is in hw_addr as a 6 byte unsigned char 
> array. Flags is for any arp-flags.
> 
> bool arp_get (const in_addr_t ip, unsigned char *hw_addr, int *flags)
> {
>     int                 ret;
>     int                 fd;
>     struct arpreq       arpreq = {0};
>     struct sockaddr_in *sin = NULL;
> 
>     fd = socket (PF_INET, SOCK_DGRAM, IPPROTO_IP);
>     if (fd == -1) {
>        return false;
>     }
>     sin = (struct sockaddr_in *)&arpreq.arp_pa;
>     sin->sin_family = AF_INET;
>     sin->sin_addr.s_addr = ip;
     strncpy(arpreq.arp_dev, "eth0", sizeof(arpreq.arp_dev));
> 
>     ret = ioctl (fd, SIOCGARP, &arpreq);
>     if (ret == -1) {
>        return false;
>     }
>     memcpy (hw_addr, &arpreq.arp_ha.sa_data[0], 6);
>     if (flags) {
>        *flags = arpreq.arp_flags;
>     }
>     close (fd);
>     return true;
> }

	Bernd
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