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| author |   Hao Zheng <hzheng@nicira.com> | 2010-11-11 13:47:57 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-11-12 12:30:57 -0800 |
| commit | 0a85df004667c99efc31fab07386823eefce3be5 (patch) | |
| tree | 2fe059bc77f52e3cdb6ab665e41dd1eba9d4fc08 | |
| parent | virtio-net: init link state correctly (diff) | |
| download | linux-dev-0a85df004667c99efc31fab07386823eefce3be5.tar.xz linux-dev-0a85df004667c99efc31fab07386823eefce3be5.zip | |
vlan: Add function to retrieve EtherType from vlan packets.
Depending on how a packet is vlan tagged (i.e. hardware accelerated or
not), the encapsulated protocol is stored in different locations. This
provides a consistent method of accessing that protocol, which is needed
by drivers, security checks, etc.
Signed-off-by: Hao Zheng <hzheng@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/if_vlan.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index c2f3a72712ce..635e1faec412 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -339,6 +339,31 @@ static inline int vlan_get_tag(const struct sk_buff *skb, u16 *vlan_tci) } } +/** + * vlan_get_protocol - get protocol EtherType. + * @skb: skbuff to query + * + * Returns the EtherType of the packet, regardless of whether it is + * vlan encapsulated (normal or hardware accelerated) or not. + */ +static inline __be16 vlan_get_protocol(const struct sk_buff *skb) +{ + __be16 protocol = 0; + + if (vlan_tx_tag_present(skb) || + skb->protocol != cpu_to_be16(ETH_P_8021Q)) + protocol = skb->protocol; + else { + __be16 proto, *protop; + protop = skb_header_pointer(skb, offsetof(struct vlan_ethhdr, + h_vlan_encapsulated_proto), + sizeof(proto), &proto); + if (likely(protop)) + protocol = *protop; + } + + return protocol; +} #endif /* __KERNEL__ */ /* VLAN IOCTLs are found in sockios.h */ |