[34-longterm 089/247] bonding/vlan: Avoid mangled NAs on slaves without VLAN tag insertion

From: Paul Gortmaker
Date: Thu Jun 23 2011 - 14:20:25 EST

From: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>

This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.

This is related to commit f88a4a9b65a6f3422b81be995535d0e69df11bb8
upstream, but the bug cannot be properly fixed without the other
changes to VLAN tagging in 2.6.37.

bond_na_send() attempts to insert a VLAN tag in between building and
sending packets of the respective formats. If the slave does not
implement hardware VLAN tag insertion then vlan_put_tag() will mangle
the network-layer header because the Ethernet header is not present at
this point (unlike in bond_arp_send()).

Signed-off-by: Ben Hutchings <bhutchings@xxxxxxxxxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
drivers/net/bonding/bond_ipv6.c | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/net/bonding/bond_ipv6.c b/drivers/net/bonding/bond_ipv6.c
index 6dd64cf..a131d6f 100644
--- a/drivers/net/bonding/bond_ipv6.c
+++ b/drivers/net/bonding/bond_ipv6.c
@@ -69,6 +69,13 @@ static void bond_na_send(struct net_device *slave_dev,
struct sk_buff *skb;

+ /* The Ethernet header is built in ndisc_send_skb(), not
+ * ndisc_build_skb(), so we cannot insert a VLAN tag. Only an
+ * out-of-line tag inserted by the hardware will work.
+ */
+ if (vlan_id && !(slave_dev->features & NETIF_F_HW_VLAN_TX))
+ return;
icmp6h.icmp6_router = router;
icmp6h.icmp6_solicited = 0;
icmp6h.icmp6_override = 1;
@@ -87,7 +94,7 @@ static void bond_na_send(struct net_device *slave_dev,

if (vlan_id) {
- skb = vlan_put_tag(skb, vlan_id);
+ skb = __vlan_hwaccel_put_tag(skb, vlan_id);
if (!skb) {
pr_err("failed to insert VLAN tag\n");

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