I'm receiving TCP packets via a raw socket. Is this normal?

Hi

I'm developing an application that uses raw sockets to send TCP
headers. According to the latest version of the Unix Network
Programming book raw sockets *never* receive TCP packets since the
kernel doesn't pass them on after its processed them (book says you
should use a PF_PACKET datalink layer type socket to receive them).

However , I've noticed on linux that a raw socket DOES receive TCP
packets. Is this normal? It seems to happen on both kernels 2.4 and
2.6. Is this a quirk of Linux which is not seen on other unixes or is
it standard behaviour and the book is wrong?

Thanks for any info

B2003