Make M_COPY_PKTHDR() macro into a wrapper for a m_copy_pkthdr()

function.  This permits conditionally compiled extensions to the
packet header copying semantic, such as extensions to copy MAC
labels.

Reviewed by:	bmilekic
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs

2 files changed, 21 insertions, 15 deletions

diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index 2c74a4c04fda..e8a679ed8d86 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -63,6 +63,25 @@ SYSCTL_INT(_kern_ipc, KIPC_MAX_DATALEN, max_datalen, CTLFLAG_RW,
 	   &max_datalen, 0, "");
 
 /*
+ * Copy mbuf pkthdr from "from" to "to".
+ * "from" must have M_PKTHDR set, and "to" must be empty.
+ * aux pointer will be moved to "to".
+ */
+void
+m_copy_pkthdr(struct mbuf *to, struct mbuf *from)
+{
+
+#if 0
+	KASSERT(to->m_flags & M_PKTHDR,
+	    ("m_copy_pkthdr() called on non-header"));
+#endif
+	to->m_data = to->m_pktdat;
+	to->m_flags = from->m_flags & M_COPYFLAGS;
+	to->m_pkthdr = from->m_pkthdr;
+	from->m_pkthdr.aux = NULL;
+}
+
+/*
  * Lesser-used path for M_PREPEND:
  * allocate new mbuf to prepend to chain,
  * copy junk along.
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 0f3669476b9c..437a19220c40 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -280,6 +280,7 @@ struct mbstat {
  * mbuf, cluster, and external object allocation macros
  * (for compatibility purposes).
  */
+#define	M_COPY_PKTHDR(to, from)	m_copy_pkthdr(to, from)
 #define	m_getclr		m_get_clrd
 #define	MGET(m, how, type)	(m) = m_get((how), (type))
 #define	MGETHDR(m, how, type)	(m) = m_gethdr((how), (type))
@@ -312,21 +313,6 @@ struct mbstat {
 #define	M_WRITABLE(m)	(!((m)->m_flags & M_RDONLY) && (!((m)->m_flags  \
 			    & M_EXT) || !MEXT_IS_REF(m)))
 
-/*-
- * Copy mbuf pkthdr from "from" to "to".
- * "from" must have M_PKTHDR set, and "to" must be empty.
- * aux pointer will be moved to "to".
- */
-#define	M_COPY_PKTHDR(to, from) do {					\
-	struct mbuf *_mfrom = (from);					\
-	struct mbuf *_mto = (to);					\
-									\
-	_mto->m_data = _mto->m_pktdat;					\
-	_mto->m_flags = _mfrom->m_flags & M_COPYFLAGS;			\
-	_mto->m_pkthdr = _mfrom->m_pkthdr;				\
-	_mfrom->m_pkthdr.aux = NULL;					\
-} while (0)
-
 /*
  * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
  * an object of the specified size at the end of the mbuf, longword aligned.
@@ -487,6 +473,7 @@ void		 m_copyback(struct mbuf *, int, int, caddr_t);
 void		 m_copydata(const struct mbuf *, int, int, caddr_t);
 struct	mbuf	*m_copym(struct mbuf *, int, int, int);
 struct	mbuf	*m_copypacket(struct mbuf *, int);
+void		 m_copy_pkthdr(struct mbuf *to, struct mbuf *from);
 struct	mbuf	*m_devget(char *, int, int, struct ifnet *,
 		    void (*copy)(char *, caddr_t, u_int));
 struct	mbuf	*m_dup(struct mbuf *, int);