how to determinate destination MAC address

Question

My application is running on CentOS 5.5 I need to send raw packets using libpcap API:

pcap_inject() or pcap_sendpacket()

To the specific IP add

Answer 1

It looks like what you want is ioctl and SIOCGARP. That should let you query your arp cache. I'm assuming that the host in question is on your local network or all you're going to get is your router.

You can also read from /proc/net/arp, which seems easier. You'll need to get an arp request returned first but you'll be doing that whether your tool does it or some third-party makes the request.