I was looking through the code in netinet/udp_usrreq.c and noticed that
the mbuf chain was copied both for unicast and broadcast/multicast
packets in udp4_realinput() (the copy operation is invoked from
udp4_sendup()).  It seems to me that in the unicast case there is no
apparent reason for this.  Prior to rev. 1.53 the copying did only
happen for the broadcast/multicast case.

Does anyone know why the extra copying was introduced for the unicast
case?

Regards,
Pal Sommerhein