Commit eb3f8b42 authored Nov 17, 2015 by David S. Miller

Merge branch 'vlan-reorder'



Vladislav Yasevich says:

====================
Fix issues with vlans without REORDER_HEADER

A while ago Phil Sutter brought up an issue with vlans without
REORDER_HEADER and bridges.  The problem was that if a vlan
without REORDER_HEADER was a port in the bridge, the bridge ended
up forwarding corrupted packets that still contained the vlan header.
The same issue exists for bridge mode macvlan/macvtap devices.

An additional issue with vlans without REORDER_HEADER is that stacking
them also doesn't work.  The reason here is that skb_reorder_vlan_header()
function assumes that it on ETH_HLEN bytes deep into the packet.  That
is not the case, when you a vlan without REORRDER_HEADER flag set.

This series attempts to correct these 2 issues.

1) To solve the stacked vlans problem, the patch simply use
skb->mac_len as an offset to start copying mac addresses that
is part of header reordering.

2) To fix the issue with bridge/macvlan/macvtap, the second patch
simply doesn't write the vlan header back to the packet if the
vlan device is either a bridge or a macvlan port.  This ends up
being the simplest and least performance intrussive solution.

I've considered extending patch 2 to all stacked devices (essentially
checked for the presense of rx_handler), but that feels like a broader
restriction and _may_ break existing uses.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

parents 6c606fa3 28f9ee22

include/linux/netdevice.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -3857,6 +3857,11 @@ static inline bool netif_is_bridge_master(const struct net_device *dev)
		return dev->priv_flags & IFF_EBRIDGE;
		}

		static inline bool netif_is_bridge_port(const struct net_device *dev)
		{
		return dev->priv_flags & IFF_BRIDGE_PORT;
		}

		static inline bool netif_is_ovs_master(const struct net_device *dev)
		{
		return dev->priv_flags & IFF_OPENVSWITCH;

net/8021q/vlan_core.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -30,7 +30,9 @@ bool vlan_do_receive(struct sk_buff **skbp)
		skb->pkt_type = PACKET_HOST;
		}

		if (!(vlan_dev_priv(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR)) {
		if (!(vlan_dev_priv(vlan_dev)->flags & VLAN_FLAG_REORDER_HDR) &&
		!netif_is_macvlan_port(vlan_dev) &&
		!netif_is_bridge_port(vlan_dev)) {
		unsigned int offset = skb->data - skb_mac_header(skb);

		/*

net/core/skbuff.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -4268,7 +4268,8 @@ static struct sk_buff skb_reorder_vlan_header(struct sk_buff skb)
		return NULL;
		}

		memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN);
		memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len,
		2 * ETH_ALEN);
		skb->mac_header += VLAN_HLEN;
		return skb;
		}

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