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Message-ID: <20100412221645.8068.71073.stgit@localhost6.localdomain6>
Date: Mon, 12 Apr 2010 15:17:17 -0700
From: Chris Leech <christopher.leech@...el.com>
To: netdev@...r.kernel.org, Andy Gospodarek <andy@...yhouse.net>,
Patrick McHardy <kaber@...sh.net>
Cc: bonding-devel@...ts.sourceforge.net
Subject: Receive issues with bonding and vlans
Quick summary: VLANs and bonding are interacting in strange ways in the
receive path, VLAN devices do not act the same as real Ethernet devices,
hardware accelerated VLANs do not act the same as software tagged VLANs,
and I think frames are incorrectly being passed up to protocols from
inactive bonding links.
I've been looking at high availability configurations for converged LAN
+ SAN networking, trying to see what running FCoE and IP traffic looked
like with bonding and dm_multipath. The goal is to allow sysadmins to
use the tools they are already using with separate LAN and SAN adapters,
now on a single converged adapter.
The setup I'm trying to use looks like this; with IP traffic running on
bond0, storage VLANs created on eth0 and eth1, and FCoE running on the
VLANs. Both switches provide Fiber Channel Forwarder (FCF) services,
and connect to the same LAN and SAN.
.-----------------------------------------.
| .--------------. |
| | dm_multipath | |
| '--------------' |
| ^ |
| .----------. | .----------. |
| | fc_host0 |--------'------| fc_host1 | |
| '----------' '----------' |
| ^ ^ |
| | | |
| .----------. .-------. .----------. |
| | eth0.101 | | bond0 | | eth1.101 | |
| '----------' '-------' '----------' |
| ^ ^ ^ |
| | .------. | .------. | |
| '-| eth0 |---'----| eth1 |-' |
| '------' '------' |
'-------------|---------------|-----------'
| |
v v
.----------. .----------.
| switch A |----| switch B |
'----------' '----------'
| | | |
.--'--'------------'--'-.
| |
v v
.-,( ),-. .-,( ),-.
.-( )-. .-( )-.
( FC SAN ) ( IP LAN )
'-( ).-' '-( ).-'
'-.( ).-' '-.( ).-'
bond0 is in active-backup mode, but FCoE is actively running on both
links providing two different paths into the SAN. This configuration
matches a typical HA setup with separate Ethernet + FC adapters. In
this case I'm interested in software convergence where all traffic
passes through the standard network transmit and receive paths.
The VLANs aren't strictly required by FCoE, but it is the recommended
best practice by switch vendors. The FCF switches map FC VSANs to
VLANs.
Ever since this series of changes to net/core/dev.c
Author: Joe Eykholt <jre@...vasystems.com>
Date: Wed Jul 2 18:22:02 2008 -0700
net/core: Uninline skb_bond().
net/core: Allow certain receives on inactive slave.
net/core: Allow receive on active slaves.
it has been possible to receive directly on both active and inactive
slave links if the packet_type specifies the slave device. This
combined with the PACKET_ORIGDEV socket option allowed for FCoE to run
on the slave devices (DCB link configuration uses a userspace LLDP
agent, and FCoE includes a VLAN discovery protocol that is implemented
in userspace as well).
The problem is that it doesn't work for hardware accelerated VLAN
devices, because the VLAN receive paths have their own
skb_bond_should_drop calls that were not updated.
>>From what I can tell, VLAN receives always end up going through
netif_receive_skb anyway, so skb_bond_should_drop gets called twice if
the frame isn't dropped the first time. I think the bonding checks in
__vlan_hwaccel_rx and vlan_gro_common should just be removed.
@@ -11,9 +11,6 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
if (netpoll_rx(skb))
return NET_RX_DROP;
- if (skb_bond_should_drop(skb, ACCESS_ONCE(skb->dev->master)))
- goto drop;
-
skb->skb_iif = skb->dev->ifindex;
__vlan_hwaccel_put_tag(skb, vlan_tci);
skb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);
@@ -83,9 +80,6 @@ vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
{
struct sk_buff *p;
- if (skb_bond_should_drop(skb, ACCESS_ONCE(skb->dev->master)))
- goto drop;
-
skb->skb_iif = skb->dev->ifindex;
__vlan_hwaccel_put_tag(skb, vlan_tci);
skb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);
That fixes my setup ... but thinking about it raised some more
questions. The VLAN discovery tool I wrote shouldn't have worked, I
didn't bother to bind a packet socket to each interface I wanted to use.
So a single unbound packet socket is successfully passing traffic on
both active and inactive slave interfaces, which from my understanding
shouldn't work. It's easier for me this way, but it still seems wrong.
I think the problem was introduced with these changes.
Author: Andy Gospodarek <andy@...yhouse.net>
Date: Wed Jan 6 12:56:37 2010 +0000
fix bonding: allow arp_ip_targets on separate vlans to use arp validation
Date: Mon Dec 14 10:48:58 2009 +0000
bonding: allow arp_ip_targets on separate vlans to use arp validation
The use of null_or_bond in netif_receive_skb looks suspicious to me. In
the presence of both bonding and VLANs it probably does what was
intended. Without VLANs however, it is always set to NULL which matches
unbound packet_types. So unbound packet_types will process all frames
received on an inactive slave link, ignoring the result of
skb_bond_should_drop.
I haven't quite figured out what I think the correct change for
null_or_bond is. I suspect it involves not using NULL at all. I can
see how it addresses the arp_ip_target on a VLAN issue, but this is also
changing the receive matching rules for other traffic in unexpected
ways.
- Chris
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