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, 2 deletions

diff --git a/sys/netatm/port.h b/sys/netatm/port.h
index 83e0654..df599ad 100644
--- a/sys/netatm/port.h
+++ b/sys/netatm/port.h
@@ -178,8 +178,7 @@ typedef struct mbuf	KBuffer;
 }
 #define	KB_LINKHEAD(new, head) {			\
 	if ((head) && KB_ISPKT(new) && KB_ISPKT(head)) {\
-		M_COPY_PKTHDR((new), (head));		\
-		(head)->m_flags &= ~M_PKTHDR;		\
+		M_MOVE_PKTHDR((new), (head));		\
 	}						\
 	(new)->m_next = (head);				\
 }