From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Gross Subject: [PATCH net-2.6 v2 1/3] vlan: Add function to retrieve EtherType from vlan packets. Date: Thu, 11 Nov 2010 15:47:57 -0800 Message-ID: <1289519279-20641-1-git-send-email-jesse@nicira.com> Cc: netdev , Hao Zheng To: David Miller Return-path: Received: from mail-vw0-f46.google.com ([209.85.212.46]:49442 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752518Ab0KKXsI (ORCPT ); Thu, 11 Nov 2010 18:48:08 -0500 Received: by vws13 with SMTP id 13so732754vws.19 for ; Thu, 11 Nov 2010 15:48:06 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: From: Hao Zheng 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 Signed-off-by: Jesse Gross -- Changes from v1: * Use skb_header_pointer() instead of pskb_may_pull() when retrieving possibly paged data inside the vlan header to avoid invalidating the pointers of callers. --- 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 c2f3a72..635e1fa 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 */ -- 1.7.1