redo most of the protocol (tcp/udp/...) checksum handling

-assume we have hardware checksum offloading. stop mucking with the
 checksum in most of the stack
-stop checksum mucking in pf, just set a "needs checksumming" flag if needed
-in all output pathes, very late, if we figure out the outbound interface
 doesn't have hw cksum offloading, do the cksum in software. this especially
 makes the bridge path behave like a regular output path
-little special casing for bridge still required until the broadcast path
 loses its disgusting shortcut hacks, but at least it's in one place now
 and not all over the stack
in6_proto_cksum_out mostly written by krw@
started at k2k11 in iceland more than 1.5 years ago - yes it took that
long, this stuff is everything but easy.
this happens to fix the infamous pf rdr bug that made us turn off proto
cksum offloading on almost all interface drivers.
ok camield sthen claudio, testing by many, thanks!

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/netinet6/in6.h b/sys/netinet6/in6.h
index 9bbec7df68d..ad01de151cb 100644
--- a/sys/netinet6/in6.h
+++ b/sys/netinet6/in6.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in6.h,v 1.59 2012/09/17 20:01:26 yasuoka Exp $	*/
+/*	$OpenBSD: in6.h,v 1.60 2012/11/01 07:55:56 henning Exp $	*/
 /*	$KAME: in6.h,v 1.83 2001/03/29 02:55:07 jinmei Exp $	*/
 
 /*
@@ -758,6 +758,7 @@ struct ip6_mtuinfo {
 struct cmsghdr;
 
 int	in6_cksum(struct mbuf *, u_int8_t, u_int32_t, u_int32_t);
+extern void in6_proto_cksum_out(struct mbuf *, struct ifnet *);
 int	in6_localaddr(struct in6_addr *);
 int	in6_addrscope(struct in6_addr *);
 struct	in6_ifaddr *in6_ifawithscope(struct ifnet *, struct in6_addr *, u_int);