2 * Copyright (c) 2007-2011 Nicira, Inc.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 #include <linux/if_vlan.h>
23 #include <linux/skbuff.h>
24 #include <linux/version.h>
27 * DOC: VLAN tag manipulation.
29 * &struct sk_buff handling of VLAN tags has evolved over time:
31 * In 2.6.26 and earlier, VLAN tags did not have any generic representation in
32 * an skb, other than as a raw 802.1Q header inside the packet data.
34 * In 2.6.27 &struct sk_buff added a @vlan_tci member. Between 2.6.27 and
35 * 2.6.32, its value was the raw contents of the 802.1Q TCI field, or zero if
36 * no 802.1Q header was present. This worked OK except for the corner case of
37 * an 802.1Q header with an all-0-bits TCI, which could not be represented.
39 * In 2.6.33, @vlan_tci semantics changed. Now, if an 802.1Q header is
40 * present, then the VLAN_TAG_PRESENT bit is always set. This fixes the
41 * all-0-bits TCI corner case.
43 * For compatibility we emulate the 2.6.33+ behavior on earlier kernel
44 * versions. The client must not access @vlan_tci directly. Instead, use
45 * vlan_get_tci() to read it or vlan_set_tci() to write it, with semantics
46 * equivalent to those on 2.6.33+.
49 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
50 #define NEED_VLAN_FIELD
53 #ifndef NEED_VLAN_FIELD
54 static inline void vlan_copy_skb_tci(struct sk_buff *skb) { }
56 static inline u16 vlan_get_tci(struct sk_buff *skb)
58 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
60 return skb->vlan_tci | VLAN_TAG_PRESENT;
65 static inline void vlan_set_tci(struct sk_buff *skb, u16 vlan_tci)
67 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,33)
68 vlan_tci &= ~VLAN_TAG_PRESENT;
70 skb->vlan_tci = vlan_tci;
73 void vlan_copy_skb_tci(struct sk_buff *skb);
74 u16 vlan_get_tci(struct sk_buff *skb);
75 void vlan_set_tci(struct sk_buff *skb, u16 vlan_tci);
77 #undef vlan_tx_tag_present
78 bool vlan_tx_tag_present(struct sk_buff *skb);
80 #undef vlan_tx_tag_get
81 u16 vlan_tx_tag_get(struct sk_buff *skb);
83 #define __vlan_hwaccel_put_tag rpl__vlan_hwaccel_put_tag
84 struct sk_buff *__vlan_hwaccel_put_tag(struct sk_buff *skb, u16 vlan_tci);
85 #endif /* NEED_VLAN_FIELD */
87 static inline int vlan_deaccel_tag(struct sk_buff *skb)
89 if (!vlan_tx_tag_present(skb))
92 skb = __vlan_put_tag(skb, vlan_tx_tag_get(skb));
96 if (get_ip_summed(skb) == OVS_CSUM_COMPLETE)
97 skb->csum = csum_add(skb->csum,
98 csum_partial(skb->data + (2 * ETH_ALEN),
101 vlan_set_tci(skb, 0);