o eliminate separate callback interface for h/w tagged input packets; instead

  drivers "tag packets" with an m_tag and the input packet handling recognizes
  such packets and does the right thing
o track the number of active vlans on an interface; this lets lots of places
  only do vlan-specific processing when needed
o track changes to ether_ifdetach/ether_ifattach
o track bpf changes
o eliminate the use of M_PROTO1 for communicating to drivers about tagged
  packets
o eliminate the use of IFF_LINK0 for drivers communicating to the vlan code
  that they support h/w tagging; replaced by explicit interface capabilities
o add ifnet capabilities for h/w tagging and support of "large mtu's"
o use new interface capabilities to auto-configure use of large mtu's and h/w
  tagging
o add support for proper handling of promiscuous mode
o document driver/vlan communication conventions

Reviewed by:	many
Approved by:	re

1 files changed, 57 insertions, 22 deletions

diff --git a/sys/net/if_vlan_var.h b/sys/net/if_vlan_var.h
index c74064a..42f2dcc 100644
--- a/sys/net/if_vlan_var.h
+++ b/sys/net/if_vlan_var.h
@@ -32,27 +32,6 @@
 #ifndef _NET_IF_VLAN_VAR_H_
 #define	_NET_IF_VLAN_VAR_H_	1
 
-#ifdef _KERNEL
-struct vlan_mc_entry {
-	struct ether_addr		mc_addr;
-	SLIST_ENTRY(vlan_mc_entry)	mc_entries;
-};
-
-struct	ifvlan {
-	struct	arpcom ifv_ac;	/* make this an interface */
-	struct	ifnet *ifv_p;	/* parent inteface of this vlan */
-	struct	ifv_linkmib {
-		int	ifvm_parent;
-		u_int16_t ifvm_proto; /* encapsulation ethertype */
-		u_int16_t ifvm_tag; /* tag to apply on packets leaving if */
-	}	ifv_mib;
-	SLIST_HEAD(__vlan_mchead, vlan_mc_entry)	vlan_mc_listhead;
-	LIST_ENTRY(ifvlan) ifv_list;
-};
-#define	ifv_if	ifv_ac.ac_if
-#define	ifv_tag	ifv_mib.ifvm_tag
-#endif /* _KERNEL */
-
 struct	ether_vlan_header {
 	u_char	evl_dhost[ETHER_ADDR_LEN];
 	u_char	evl_shost[ETHER_ADDR_LEN];
@@ -63,7 +42,6 @@ struct	ether_vlan_header {
 
 #define	EVL_VLANOFTAG(tag) ((tag) & 4095)
 #define	EVL_PRIOFTAG(tag) (((tag) >> 13) & 7)
-#define	EVL_ENCAPLEN	4	/* length in octets of encapsulation */
 
 /* sysctl(3) tags, for compatibility purposes */
 #define	VLANCTL_PROTO	1
@@ -79,4 +57,61 @@ struct	vlanreq {
 #define	SIOCSETVLAN	SIOCSIFGENERIC
 #define	SIOCGETVLAN	SIOCGIFGENERIC
 
+#ifdef _KERNEL
+/*
+ * Drivers that are capable of adding and removing the VLAN header
+ * in hardware indicate they support this by marking IFCAP_VLAN_HWTAGGING
+ * in if_capabilities.  Drivers for hardware that is also capable
+ * of handling larger MTU's that may include a software-appended
+ * VLAN header w/o lowering the normal MTU should mark IFCAP_VLA_MTU
+ * in if_capabilities; this notfies the VLAN code it can leave the
+ * MTU on the vlan interface at the normal setting.
+ */
+
+/*
+ * Drivers that support hardware VLAN tagging pass a packet's tag
+ * up through the stack by appending a packet tag with this value.
+ * Output is handled likewise, the driver must locate the packet
+ * tag to extract the VLAN tag.  The following macros are used to
+ * do this work.  On input, do:
+ *
+ *	VLAN_INPUT_TAG(ifp, m, tag,);
+ *
+ * to mark the packet m with the specified VLAN tag.  The last
+ * parameter provides code to execute in case of an error.  On
+ * output the driver should check ifnet to see if any VLANs are
+ * in use and only then check for a packet tag; this is done with:
+ *
+ *	struct m_tag *mtag;
+ *	mtag = VLAN_OUTPUT_TAG(ifp, m);
+ *	if (mtag != NULL) {
+ *		... = VLAN_TAG_VALUE(mtag);
+ *		... pass tag to hardware ...
+ *	}
+ *
+ * Note that a driver must indicate it supports hardware VLAN
+ * tagging by marking IFCAP_VLAN_HWTAGGING in if_capabilities.
+ */
+#define	MTAG_VLAN	1035328035
+#define	MTAG_VLAN_TAG	0		/* tag of VLAN interface */
+
+#define	VLAN_INPUT_TAG(_ifp, _m, _t, _errcase) do {		\
+	struct m_tag *mtag;					\
+	mtag = m_tag_alloc(MTAG_VLAN, MTAG_VLAN_TAG,		\
+			   sizeof (u_int), M_DONTWAIT);		\
+	if (mtag == NULL) {					\
+		(_ifp)->if_ierrors++;				\
+		m_freem(_m);					\
+		_errcase;					\
+	}							\
+	*(u_int *)(mtag+1) = (_t);				\
+	m_tag_prepend((_m), mtag);				\
+} while (0)
+
+#define	VLAN_OUTPUT_TAG(_ifp, _m)				\
+	((_ifp)->if_nvlans != 0 ?				\
+		m_tag_locate((_m), MTAG_VLAN, MTAG_VLAN_TAG, NULL) : NULL)
+#define	VLAN_TAG_VALUE(_mt)	(*(u_int *)((_mt)+1))
+#endif /* _KERNEL */
+
 #endif /* _NET_IF_VLAN_VAR_H_ */