PERFORCE change 39325 for review

[Sam Leffler]

http://perforce.freebsd.org/chv.cgi?CH=39325

Change 39325 by sam at sam_ebb on 2003/10/07 12:03:33

	Add notion of persistent tags and strip all non-persistent
	tags when mbufs are "turned around" through the loopback
	interface or in ICMP.

Affected files ...

.. //depot/projects/netperf/sys/kern/uipc_mbuf2.c#2 edit
.. //depot/projects/netperf/sys/net/if_loop.c#6 edit
.. //depot/projects/netperf/sys/netinet/ip_icmp.c#5 edit
.. //depot/projects/netperf/sys/sys/mbuf.h#3 edit

Differences ...

==== //depot/projects/netperf/sys/kern/uipc_mbuf2.c#2 (text+ko) ====

@@ -381,6 +381,23 @@
 	m_tag_delete(m, p);
 }
 
+/*
+ * Strip off all tags that would normally vanish when
+ * passing through a network interface.  Only persistent
+ * tags will exist after this; these are expected to remain
+ * so long as the mbuf chain exists, regardless of the
+ * path the mbufs take.
+ */
+void
+m_tag_delete_nonpersistent(struct mbuf *m)
+{
+	struct m_tag *p, *q;
+
+	SLIST_FOREACH_SAFE(p, &m->m_pkthdr.tags, m_tag_link, q)
+		if ((p->m_tag_id & MTAG_PERSISTENT) == 0)
+			m_tag_delete(m, p);
+}
+
 /* Find a tag, starting from a given position. */
 struct m_tag *
 m_tag_locate(struct mbuf *m, u_int32_t cookie, int type, struct m_tag *t)

==== //depot/projects/netperf/sys/net/if_loop.c#6 (text+ko) ====

@@ -266,6 +266,7 @@
 	int isr;
 
 	M_ASSERTPKTHDR(m);
+	m_tag_delete_nonpersistent(m);
 	m->m_pkthdr.rcvif = ifp;
 
 	/* BPF write needs to be handled specially */

==== //depot/projects/netperf/sys/netinet/ip_icmp.c#5 (text+ko) ====

@@ -728,6 +728,7 @@
 		bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
 			 (unsigned)(m->m_len - sizeof(struct ip)));
 	}
+	m_tag_delete_nonpersistent(m);
 	m->m_flags &= ~(M_BCAST|M_MCAST);
 	icmp_send(m, opts, ro);
 done:

==== //depot/projects/netperf/sys/sys/mbuf.h#3 (text+ko) ====

@@ -498,6 +498,21 @@
  *	struct m_tag *mtag = &p->tag;
  */
 
+/*
+ * Persistent tags stay with an mbuf until the mbuf is reclaimed.
+ * Otherwise tags are expected to ``vanish'' when they pass through
+ * a network interface.  For most interfaces this happens normally
+ * as the tags are reclaimed when the mbuf is free'd.  However in
+ * some special cases reclaiming must be done manually.  An example
+ * is packets that pass through the loopback interface.  Also, one
+ * must be careful to do this when ``turning around'' packets (e.g.
+ * icmp_reflect).
+ *
+ * To mark a tag persistent bit-or this flag in when defining the
+ * tag id.  The tag will then be treated as described above.
+ */
+#define	MTAG_PERSISTENT				0x800
+
 #define	PACKET_TAG_NONE				0  /* Nadda */
 
 /* Packet tag for use with PACKET_ABI_COMPAT */
@@ -535,7 +550,7 @@
 #define	PACKET_TAG_IPFW				16 /* ipfw classification */
 #define	PACKET_TAG_DIVERT			17 /* divert info */
 #define	PACKET_TAG_IPFORWARD			18 /* ipforward info */
-#define	PACKET_TAG_MACLABEL			19 /* MAC label */
+#define	PACKET_TAG_MACLABEL	(19 | MTAG_PERSISTENT) /* MAC label */
 
 /* Packet tag routines */
 struct	m_tag 	*m_tag_alloc(u_int32_t, int, int, int);
@@ -550,6 +565,7 @@
 void		 m_tag_init(struct mbuf *);
 struct	m_tag	*m_tag_first(struct mbuf *);
 struct	m_tag	*m_tag_next(struct mbuf *, struct m_tag *);
+void		 m_tag_delete_nonpersistent(struct mbuf *);
 
 /* these are for openbsd compatibility */
 #define	MTAG_ABI_COMPAT		0		/* compatibility ABI */