How to read packet by packet from linux tun/tap

Question

I have connected to an existing Tap device using

fd = open(...)

Now i want to read from it packet by packet. if i use

read(fd,buffer,sizeof(buffer));

I wont read exactly 1 packet.

How can i read exactly 1 packet? Is there some kind of header that says the packet length or in the worst case i will have to parse the packet and figure the length myself?

Answer 1

I was wrong about the way read() reads bytes from a tap device. It turns out when I use read() it reads exactly 1 frame, (or n bytes if n is smaller then frame size)