Single UDP sockets : duplex capable?

[Garrett Cooper]

Hello,

    Just wondering, abstractly..

 -------------------------
| A -[socket (UDP)]-> B |
 -------------------------

    A creates a UDP socket (call it 's1') to talk to B.

    Can B use the same socket ('s2') to talk to A using read(2) or 
recv(2), or does A have to accept(2) traffic from B using a different 
socket?

    The programming language I'm using is C (not C++).

Thanks,
-Garrett