From a947b0a93efa9a25c012aa88848f4cf8d9b41280 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel Date: Fri, 22 Feb 2013 10:54:54 +0100 Subject: xfrm: allow to avoid copying DSCP during encapsulation By default, DSCP is copying during encapsulation. Copying the DSCP in IPsec tunneling may be a bit dangerous because packets with different DSCP may get reordered relative to each other in the network and then dropped by the remote IPsec GW if the reordering becomes too big compared to the replay window. It is possible to avoid this copy with netfilter rules, but it's very convenient to be able to configure it for each SA directly. This patch adds a toogle for this purpose. By default, it's not set to maintain backward compatibility. Field flags in struct xfrm_usersa_info is full, hence I add a new attribute. Signed-off-by: Nicolas Dichtel Signed-off-by: Steffen Klassert --- net/ipv4/xfrm4_mode_tunnel.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'net/ipv4/xfrm4_mode_tunnel.c') diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c index fe5189e2e114..eb1dd4d643f2 100644 --- a/net/ipv4/xfrm4_mode_tunnel.c +++ b/net/ipv4/xfrm4_mode_tunnel.c @@ -103,8 +103,12 @@ static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb) top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); - /* DS disclosed */ - top_iph->tos = INET_ECN_encapsulate(XFRM_MODE_SKB_CB(skb)->tos, + /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */ + if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) + top_iph->tos = 0; + else + top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos; + top_iph->tos = INET_ECN_encapsulate(top_iph->tos, XFRM_MODE_SKB_CB(skb)->tos); flags = x->props.flags; -- cgit v1.2.1