Merge the //depot/user/yar/vlan branch into CVS. It contains some collective

work by yar, thompsa and myself. The checksum offloading part also involves
work done by Mihail Balikov.

The most important changes:

o   Instead of global linked list of all vlan softc use a per-trunk
  hash. The size of hash is dynamically adjusted, depending on
  number of entries. This changes struct ifnet, replacing counter
  of vlans with a pointer to trunk structure. This change is an
  improvement for setups with big number of VLANs, several interfaces
  and several CPUs. It is a small regression for a setup with a single
  VLAN interface.
    An alternative to dynamic hash is a per-trunk static array with
  4096 entries, which is a compile time option - VLAN_ARRAY. In my
  experiments the array is not an improvement, probably because such
  a big trunk structure doesn't fit into CPU cache.
o   Introduce an UMA zone for VLAN tags. Since drivers depend on it,
  the zone is declared in kern_mbuf.c, not in optional vlan(4) driver.
  This change is a big improvement for any setup utilizing vlan(4).
o   Use rwlock(9) instead of mutex(9) for locking. We are the first
  ones to do this! :)
o   Some drivers can do hardware VLAN tagging + hardware checksum
  offloading. Add an infrastructure for this. Whenever vlan(4) is
  attached to a parent or parent configuration is changed, the flags
  on vlan(4) interface are updated.

In collaboration with:	yar, thompsa
In collaboration with:	Mihail Balikov <mihail.balikov interbgc.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/net/if.h b/sys/net/if.h
index 460f374..8e483cc 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -191,6 +191,7 @@ struct if_data {
 #define	IFCAP_VLAN_HWTAGGING	0x0010	/* hardware VLAN tag support */
 #define	IFCAP_JUMBO_MTU		0x0020	/* 9000 byte MTU supported */
 #define	IFCAP_POLLING		0x0040	/* driver supports polling */
+#define	IFCAP_VLAN_HWCSUM	0x0080	/* can do IFCAP_HWCSUM on VLANs */
 
 #define IFCAP_HWCSUM		(IFCAP_RXCSUM | IFCAP_TXCSUM)