Re: Moving ethernet VLAN tags into the mbuf packet header (from mtags)
- From: Peter Jeremy <peterjeremy@xxxxxxxxxxxxxxxx>
- Date: Sat, 9 Sep 2006 08:07:09 +1000
On Thu, 2006-Sep-07 17:07:25 +0200, Andre Oppermann wrote:
With the recent addition of a 16bit field for TSO into the mbuf packet
header we've got 16bits left over. I've reserved these bits for the
ethernet VLAN tagging of packet to do away with the allocated mbuf mtag.
Sounds reasonable. My only comment is that there doesn't appear to
be any way for bpf(4) to filter/capture VLAN information.
Before hardware tagging, you could run tcpdump on the vlan parent device
and filter on the VLAN tag as well as see the VLAN associated with each
packet. I found this very useful for monitoring routed data as well as
finding cases where packets were appearing in the wrong VLAN.
With hardware tagging (with or without this patch), bpf doesn't have
access to the tag information. This is a PITA.
--
Peter Jeremy
Attachment:
pgpf8tYZzCYgy.pgp
Description: PGP signature
- References:
- Moving ethernet VLAN tags into the mbuf packet header (from mtags)
- From: Andre Oppermann
- Moving ethernet VLAN tags into the mbuf packet header (from mtags)
- Prev by Date: Re: Is it Core 2 Duo compatible?
- Next by Date: Re: Modularize kernel
- Previous by thread: Re: Moving ethernet VLAN tags into the mbuf packet header (from mtags)
- Next by thread: SCTP in FreeBSD 5.x/current
- Index(es):
Relevant Pages
- Re: [was] addition to ipfw (read vlans from bridge)..
... into the packet as well as the packet, then yes I like that idea, ... At the
moment I plan the ipfw code to be unaware of vlan headers. ... What we need to do
is make a convention so that vlan tags are always ... (freebsd-net) - expected behavior of PF_PACKET on NETIF_F_HW_VLAN_RX device?
... the complete packet with vlan tag included as the driver simply calls ... thing
vlan tag included and sends this through the socket. ... The packet socket gets
everything including the vlan tag as I'd ... (Linux-Kernel) - Re: addition to ipfw..
... I would like to add something similar in the case where a vlan ... tag is also
on the packet.. ... Then the vlan header is also held back so that the packet can
be ... This allows me to filter packets that are traversing my bridge, ... (freebsd-net) - Re: addition to ipfw..
... I would like to add something similar in the case where a vlan ... tag is also
on the packet.. ... Then the vlan header is also held back so that the packet can
be ... The ipfw will be ignoring the vlan contents.. ... (freebsd-net) - Re: addition to ipfw..
... I would like to add something similar in the case where a vlan tag ... is also
on the packet.. ... Then the vlan header is also held back so that the packet can
be ... This allows me to filter packets that are traversing my bridge, ... (freebsd-net)
