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Commit 0a85df00 authored by Hao Zheng's avatar Hao Zheng Committed by David S. Miller
Browse files

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: default avatarHao Zheng <hzheng@nicira.com>
Signed-off-by: default avatarJesse Gross <jesse@nicira.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 167c25e4

include/linux/if_vlan.h

+25 −0
Original line number Diff line number Diff line
@@ -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 */