From mboxrd@z Thu Jan 1 00:00:00 1970 From: greearb@candelatech.com Subject: [PATCH] af-packet: Add flag to distinguish VID 0 from no-vlan. Date: Wed, 25 May 2011 16:36:35 -0700 Message-ID: <1306366595-731-1-git-send-email-greearb@candelatech.com> Cc: Ben Greear To: netdev@vger.kernel.org Return-path: Received: from mail.candelatech.com ([208.74.158.172]:54858 "EHLO ns3.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752500Ab1EYXgl (ORCPT ); Wed, 25 May 2011 19:36:41 -0400 Sender: netdev-owner@vger.kernel.org List-ID: From: Ben Greear Currently, user-space cannot determine if a 0 tcp_vlan_tci means there is no VLAN tag or the VLAN ID was zero. Add flag to make this explicit. User-space can check for TP_STATUS_VLAN_VALID || tp_vlan_tci > 0, which will be backwards compatible. Older could would have just checked for tp_vlan_tci, so it will work no worse than before. Signed-off-by: Ben Greear --- :100644 100644 72bfa5a... 6d66ce1... M include/linux/if_packet.h :100644 100644 658edd1... 885d76d... M net/packet/af_packet.c include/linux/if_packet.h | 1 + net/packet/af_packet.c | 7 ++++++- 2 files changed, 7 insertions(+), 1 deletions(-) diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h index 72bfa5a..6d66ce1 100644 --- a/include/linux/if_packet.h +++ b/include/linux/if_packet.h @@ -70,6 +70,7 @@ struct tpacket_auxdata { #define TP_STATUS_COPY 0x2 #define TP_STATUS_LOSING 0x4 #define TP_STATUS_CSUMNOTREADY 0x8 +#define TP_STATUS_VLAN_VALID 0x10 /* auxdata has valid tp_vlan_tci */ /* Tx ring - header status */ #define TP_STATUS_AVAILABLE 0x0 diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 658edd1..885d76d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1772,7 +1772,12 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock, aux.tp_snaplen = skb->len; aux.tp_mac = 0; aux.tp_net = skb_network_offset(skb); - aux.tp_vlan_tci = vlan_tx_tag_get(skb); + if (vlan_tx_tag_present(skb)) { + aux.tp_vlan_tci = vlan_tx_tag_get(skb); + aux.tp_status |= TP_STATUS_VLAN_VALID; + } + else + aux.tp_vlan_tci = 0; put_cmsg(msg, SOL_PACKET, PACKET_AUXDATA, sizeof(aux), &aux); } -- 1.7.3.4