Fix problem with UDP tunneling due to mishandled pktinfo structures.

Fix problem with UDP tunneling due to mishandled pktinfo structures.

In link_socket_write_udp_posix_sendmsg(), pktinfo structures for ipv4 and
ipv6 are going out of scope before actually calling sendmsg(), so depending
on compiler optimization, garbage is passed to sendmsg() - fix by using
"union openvpn_pktinfo" and having that in scope all the time.

Problem reported and patch provided by "danta" in trac#297

Signed-off-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Gert Doering <gert@greenie.muc.de>
Acked-by: Arne Schwabe <arne@rfc2549.org>
URL: https://community.openvpn.net/openvpn/ticket/297
Message-ID: <20130530184427.GP20843@greenie.muc.de>
URL: http://article.gmane.org/gmane.network.openvpn.devel/7629