Correct mbuf packet header propagation. Previously, packet headers

were sometimes propagated using M_COPY_PKTHDR which actually did
something between a "move" and a  "copy" operation.  This is replaced
by M_MOVE_PKTHDR (which copies the pkthdr contents and "removes" it
from the source mbuf) and m_dup_pkthdr which copies the packet
header contents including any m_tag chain.  This corrects numerous
problems whereby mbuf tags could be lost during packet manipulations.

These changes also introduce arguments to m_tag_copy and m_tag_copy_chain
to specify if the tag copy work should potentially block.  This
introduces an incompatibility with openbsd which we may want to revisit.

Note that move/dup of packet headers does not handle target mbufs
that have a cluster bound to them.  We may want to support this;
for now we watch for it with an assert.

Finally, M_COPYFLAGS was updated to include M_FIRSTFRAG|M_LASTFRAG.

Supported by:	Vernier Networks
Reviewed by:	Robert Watson <rwatson@FreeBSD.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/sys/netinet6/ip6_output.c b/sys/netinet6/ip6_output.c
index 94be84a..75ed4dc 100644
--- a/sys/netinet6/ip6_output.c
+++ b/sys/netinet6/ip6_output.c
@@ -2575,7 +2575,7 @@ ip6_splithdr(m, exthdrs)
 			m_freem(m);
 			return ENOBUFS;
 		}
-		M_COPY_PKTHDR(mh, m);
+		M_MOVE_PKTHDR(mh, m);
 		MH_ALIGN(mh, sizeof(*ip6));
 		m->m_flags &= ~M_PKTHDR;
 		m->m_len -= sizeof(*ip6);