From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ward Subject: [PATCH] ip_gre: When TOS is inherited, use configured TOS value for non-IP packets Date: Sun, 27 Jan 2013 18:04:58 -0500 Message-ID: <1359327899-8153-1-git-send-email-david.ward@ll.mit.edu> Mime-Version: 1.0 Content-Type: text/plain Cc: Timo Teras , David Ward To: Return-path: Received: from MX2.LL.MIT.EDU ([129.55.12.46]:51352 "EHLO mx2.ll.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753080Ab3A0Xjm (ORCPT ); Sun, 27 Jan 2013 18:39:42 -0500 Sender: netdev-owner@vger.kernel.org List-ID: A GRE tunnel can be configured so that outgoing tunnel packets inherit the value of the TOS field from the inner IP header. In doing so, when a non-IP packet is transmitted through the tunnel, the TOS field will always be set to 0. Instead, the user should be able to configure a different TOS value as the fallback to use for non-IP packets. This is helpful when the non-IP packets are all control packets and should be handled by routers outside the tunnel as having Internet Control precedence. One example of this is the NHRP packets that control a DMVPN-compatible mGRE tunnel; they are encapsulated directly by GRE and do not contain an inner IP header. Under the existing behavior, the IFLA_GRE_TOS parameter must be set to '1' for the TOS value to be inherited. Now, only the least significant bit of this parameter must be set to '1', and when a non-IP packet is sent through the tunnel, the upper 6 bits of this same parameter will be copied into the TOS field. (The ECN bits get masked off as before.) This behavior is backwards-compatible with existing configurations and iproute2 versions. Signed-off-by: David Ward --- net/ipv4/ip_gre.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index 303012a..e4c8817 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -818,8 +818,8 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev ttl = tiph->ttl; tos = tiph->tos; - if (tos == 1) { - tos = 0; + if (tos & 0x1) { + tos &= ~0x1; if (skb->protocol == htons(ETH_P_IP)) tos = old_iph->tos; else if (skb->protocol == htons(ETH_P_IPV6)) -- 1.7.1