mirror of
https://github.com/openvswitch/ovs
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07ac71eaa8
Signed-off-by: Pravin B Shelar <pshelar@nicira.com> Acked-by: Jesse Gross <jesse@nicira.com>
66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
/*
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* Copyright (c) 2007-2011 Nicira, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#ifndef VLAN_H
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#define VLAN_H 1
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#include <linux/if_vlan.h>
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#include <linux/skbuff.h>
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#include <linux/version.h>
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/**
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* DOC: VLAN tag manipulation.
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*
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* &struct sk_buff handling of VLAN tags has evolved over time:
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*
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* In 2.6.26 and earlier, VLAN tags did not have any generic representation in
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* an skb, other than as a raw 802.1Q header inside the packet data.
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*
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* In 2.6.27 &struct sk_buff added a @vlan_tci member. Between 2.6.27 and
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* 2.6.32, its value was the raw contents of the 802.1Q TCI field, or zero if
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* no 802.1Q header was present. This worked OK except for the corner case of
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* an 802.1Q header with an all-0-bits TCI, which could not be represented.
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*
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* In 2.6.33, @vlan_tci semantics changed. Now, if an 802.1Q header is
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* present, then the VLAN_TAG_PRESENT bit is always set. This fixes the
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* all-0-bits TCI corner case.
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*
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* For compatibility we emulate the 2.6.33+ behavior on earlier kernel
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* versions. The client must not access @vlan_tci directly. Instead, use
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* vlan_get_tci() to read it or vlan_set_tci() to write it, with semantics
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* equivalent to those on 2.6.33+.
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*/
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static inline u16 vlan_get_tci(struct sk_buff *skb)
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{
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
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if (skb->vlan_tci)
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return skb->vlan_tci | VLAN_TAG_PRESENT;
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#endif
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return skb->vlan_tci;
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}
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static inline void vlan_set_tci(struct sk_buff *skb, u16 vlan_tci)
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{
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
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vlan_tci &= ~VLAN_TAG_PRESENT;
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#endif
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skb->vlan_tci = vlan_tci;
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}
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#endif /* vlan.h */
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