Commit d65f2fa6 authored Oct 21, 2016 by Shmulik Ladkani Committed by David S. Miller Oct 23, 2016

net/sched: em_meta: Fix 'meta vlan' to correctly recognize zero VID frames



META_COLLECTOR int_vlan_tag() assumes that if the accel tag (vlan_tci)
is zero, then no vlan accel tag is present.

This is incorrect for zero VID vlan accel packets, making the following
match fail:
  tc filter add ... basic match 'meta(vlan mask 0xfff eq 0)' ...

Apparently 'int_vlan_tag' was implemented prior VLAN_TAG_PRESENT was
introduced in 05423b24 "vlan: allow null VLAN ID to be used"
(and at time introduced, the 'vlan_tx_tag_get' call in em_meta was not
 adapted).

Fix, testing skb_vlan_tag_present instead of testing skb_vlan_tag_get's
value.

Fixes: 05423b24 ("vlan: allow null VLAN ID to be used")
Fixes: 1a31f204 ("netsched: Allow meta match on vlan tag on receive")

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1bac9381

net/sched/em_meta.c

+5 −4

Original line number	Diff line number	Diff line
		@@ -176,11 +176,12 @@ META_COLLECTOR(int_vlan_tag)
		{
		unsigned short tag;

		tag = skb_vlan_tag_get(skb);
		if (!tag && __vlan_get_tag(skb, &tag))
		*err = -1;
		else
		if (skb_vlan_tag_present(skb))
		dst->value = skb_vlan_tag_get(skb);
		else if (!__vlan_get_tag(skb, &tag))
		dst->value = tag;
		else
		*err = -1;
		}

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